Department of Defense

Investigation of the Feasibility of Accommodating the

International Mobile Telecommunications (IMT) 2000

Within the 1755-1850 MHz Band

9 February 2001
DoD IMT-2000 Assessment

i

EXECUTIVE SUMMARY

In October 2000, President Clinton initiated an interagency process to consider the feasibility of

accommodating International Mobile Telecommunications for the Year 2000 (IMT-2000) within the

1755-1850 and 2500-2690 MHz radio frequency bands. The following report documents the Defense

Department’s regulatory, technical, operational, and cost assessment with respect to the feasibility of

accommodating IMT-2000 systems in the 1755-1850 MHz band.

The conclusions of this report are based on the fundamental principle that the Department of Defense

(DoD) cannot accept any degradation to mission capability resulting from a spectrum reallocation

action. Loss of access to spectrum, above and beyond that already relinquished as a result of the

Omnibus Budget Reconciliation Act of 1993 and the Balanced Budget Act of 1997, would jeopardize

the DoD’s ability to execute its mission. Congress, recognizing this principle in the National Defense

Authorization Act (NDAA) for Fiscal Year 2000, has directed that the Defense Department shall not

surrender use of a band of frequencies in which it is a primary user, as is the case with regard to the

1755-1850 band, unless an alternative band or bands are provided of comparable technical

characteristics that will ensure no loss of mission capability (as certified by the Secretary of Defense,

Chairman of the Joint Chiefs of Staff, and the Secretary of Commerce). Hence, any reallocation action

would have to meet the following specific conditions:

1. If a decision is made to vacate all or a part of the 1755-1850 MHz band, the DoD must

retain protected access until the last DoD system has migrated. Current regulatory

provisions that protect existing DoD operations in the band must continue throughout any

migration or transition period.

2. DoD must be provided regulatory protection in any new band associated with a

reallocation action equivalent to the protection currently provided in the 1755-1850 MHz

band.

3. DoD systems moving to a new band must receive timely domestic spectrum certification

and have reasonable prospect of achieving international coordination consistent with

mission requirements.

4. During any transition period in which DoD is moving out of the band or a portion thereof,

new users would be allowed to operate in the band only to the extent that their operations

do not interfere with DoD operations.

5. Timely cost reimbursement must be provided to the DoD per NDAA 1999.
DoD IMT-2000 Assessment

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The wide variety of systems the DoD operates in the 1755-1850 MHz band are unique to this band and

crucial to the defense of the United States (US) and its allies. The 1755-1850 MHz band is used for

critical national defense systems such as telemetry, tracking, and commanding of satellite systems (i.e.,

Global Positioning System (GPS), Milstar, and Defense Support Program (DSP), among others);

precision guided munitions; tactical radio relay communication systems; air combat training systems;

targeting; intelligence; and the real-time delivery of voice, video, and data information to warfighters

and their commanders. The US and its national defense forces would be at a substantial strategic and

tactical disadvantage in combat and the outcome of battles and peacekeeping operations could be

jeopardized if the DoD were to lose its use of the band without provision of comparable spectrum and

satisfaction of other conditions as presented in Section 2, Essential Conditions.

This report examines the feasibility of accommodating IMT-2000 systems by sharing the 1755-1850

MHz band with the DoD. Full band sharing was examined. Predicted interference to both IMT-2000

and DoD systems would preclude compatible operation at a large number of metropolitan areas and over

large geographic areas of the country. Unacceptable operational restrictions would be required to

mitigate the interference with IMT-2000 systems. Therefore, full band sharing is not possible.

This report also examines whether the DoD can fully vacate the 1755-1850 MHz band to accommodate

IMT-2000. The most optimistic estimates, based on funding being available in Fiscal Year 2002 (FY02)

to accomplish programmatic actions, indicate the DoD is unable to totally vacate this band until well

beyond the timelines established for this study (i.e., by 2003, 2006, or 2010). Estimates indicate that,

regardless of financial investment, vacating the band could not be accomplished for most non-space

systems until 2010 and beyond; and legacy space systems would require continued protected access to

this spectrum until 2017 and beyond. The preliminary estimated cost to transition DoD systems out of

the band in accordance with these acceptable DoD timelines, is in excess of $4.3B in Then Year dollars

(TY$). Migration prior to these dates would require premature system termination, which would have

extremely serious implications to the DoD’s ability to effectively execute its mission. Total relocation

from the band is impossible unless comparable spectrum that is operationally suitable with equivalent

regulatory protection is made available and the costs of relocation are fully reimbursed. This report,

however, indicates operationally suitable comparable spectrum may not be readily available.
DoD IMT-2000 Assessment

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Band segmentation options consistent with the options presented in the US Study Plan are also assessed.

The segmentation options are:

• Band segmentation/Partial Band Sharing

− 1755-1805 MHz retained for operation of government systems and 1805-1850 MHz

potentially reallocated to non-government use

− 1790-1850 MHz retained for operation of government systems, and 1755-1790 MHz

potentially reallocated to non-government use as part of a phased sharing approach (1710-

1755 MHz available immediately, 1755-1780 MHz available at some mid-term future date,

and 1780-1790 MHz would be made available in the long term ).

• Band segmentation/Partial Band sharing (as above) with the addition of access to Alternate

(comparable) Bands

Due to the potential for degradation to operational capability, losing access to any portion of the 1755-

1850 MHz band without access to additional comparable spectrum and adequate time to withdraw from

the specified band is unacceptable to the DoD. If the conditions of provision of comparable spectrum,

full cost reimbursement, on time program execution, and operationally protected use of the spectrum

through the course of any necessary transition are met, some band segmentation may be feasible. The

feasibility of any segmentation requires the full cooperation of, among other things, the Federal

Communications Commission, the National Telecommunications and Information Administration, the

IMT-2000 Industry, and other users of the radio spectrum. This cooperation entails acceptance of DoD

transition timelines and DoD’s continued unrestricted operation in the existing band during the course of

any transition. The timelines for accommodation of IMT-2000 in any segment of the 1755-1850 MHz

band by the DoD are comparable to those of full band sharing. Even if the above conditions are met,

transition by the DoD for this option could not be completed until 2010 and beyond for most non-space

systems and until 2017 and beyond for the space systems. The preliminary estimated cost to relocate

DoD systems in accordance with these acceptable DoD timelines, for the band segmentation options

range from at least $2.8B (TY$) to in excess of $4.3B (TY$). As in the case of vacating the total band,

migration prior to these dates would require premature system termination, which would have extremely

serious implications to the DoD’s ability to effectively execute its mission. These dates are also

predicated on funding availability in FY02.

The following bands were assessed for their ability to accommodate additional DoD systems migrated

from the 1755-1850 band due to IMT-2000 accommodation: 2025-2110 MHz; 2200-2290 MHz;

4.4-5.0 GHz; and 7-8 GHz. Preliminary review indicates these bands could not accommodate the

introduction of the additional non-space systems without operational degradation to and from critical

systems such as the Cooperative Engagement Capability, the Defense Satellite Communication System,
DoD IMT-2000 Assessment

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DoD satellite downlinks, and numerous fixed and mobile operations. The 2025-2110 MHz band may be

feasible for the introduction of the DoD satellite operations functions but there are specific regulatory

issues that must be addressed. Although other bands were not evaluated in this report, the availability of

sufficient comparable spectrum is suspect in light of the ever-growing demand and competition for

spectrum access.

In assessing the feasibility of sharing or segmentation of the designated band, or migration out of the

band, this report addressed only existing and planned DoD systems. Given the growing demand for

spectrum to support information-intensive operations, it is highly likely that new DoD requirements for

this band and other DoD bands will arise. Thus the full impact to DoD of surrendering all or a portion

of the band is likely to be greater than the assessment provided in this report.

The findings in this report are the result of a very compressed schedule, initiated by the 13 October 2000

Presidential Memorandum (PM) and the related 20 October Commerce Department Plan to Select

Spectrum for third-generation (3G) Wireless Systems in the Unites States, that did not provide time for

thorough analysis and review of the complex subject. Additional analysis may be required in some

areas. The results of this expedited study are especially sensitive to the assumptions used in the

assessment. Some of the more critical assumptions include: the relocation band selected for systems

that must move; no satellites will require replacement prior to programmed replenishment; and IMT2000 parameters. If these, or any other of the assumptions used in this assessment are altered, the results

presented will significantly differ and require reassessment. Furthermore, the timelines assumed

programming, budgeting, and contracting processes are successfully executed without schedule

perturbations. Finally, the costs estimated herein do not take into consideration the potential secondary

and tertiary costs of moving incumbent DoD users out of the band, with attendant operational changes in

tactics, training, doctrine, personnel, and long-lead procurement.
DoD IMT-2000 Assessment

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TABLE OF CONTENTS

Executive Summary ................................................................................................................i

Glossary...................................................................................................................................vii

1.0 Introduction

1.1 Background .............................................................................................................1-1

1.2 Objective .................................................................................................................1-2

1.3 Approach.................................................................................................................1-2

2.0 Essential Conditions

2.1 Conditions for Satellite Operations.........................................................................2-2

2.2 Conditions for Airborne and Terrestrial Systems ...................................................2-2

3.0 System Descriptions

3.1 IMT-2000 System Description................................................................................3-1

3.2 DoD System Descriptions.......................................................................................3-1

3.2.1 Satellite Operations (SATOPS)................................................................3-2

3.2.2 Tactical Radio Relay................................................................................3-3

3.2.3 Air Combat Training Systems (ACTS)....................................................3-4

3.2.4 Tactical Control Links/Precision Guided Munitions ...............................3-5

3.2.5 Other Systems ..........................................................................................3-6

4.0 Assessment Approach

4.1 Integration of Technical, Operational, and Cost Assessments................................4-1

4.2 Technical Assessment Approach ............................................................................4-1

4.3 Operational Impact Assessment Approach .............................................................4-3

4.4 Cost Assessment Approach.....................................................................................4-3

5.0 Critical Assumptions

5.1 Overall Study Assumptions ....................................................................................5-1

5.2 Technical Assumptions ...........................................................................................5-1

5.3 Operational Assumptions........................................................................................5-1

5.4 Cost Assumptions ...................................................................................................5-2

5.5 Schedule Assumptions ............................................................................................5-2

5.6 IMT-2000 Assumptions ..........................................................................................5-2

5.7 SATOPS Assumptions............................................................................................5-3

5.8 Tactical Radio Relay Assumptions .........................................................................5-3

5.9 ACTS Assumptions.................................................................................................5-3

5.10 Tactical Control Links/PGM Assumptions...........................................................5-4

5.11 Other System Assumptions...................................................................................5-4
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6.0 Summary of Results

6.1 Results for Considered Options ..............................................................................6-1

6.1.1 Full Band Sharing ....................................................................................6-3

6.1.2 Band Segmentation/Partial Band Sharing................................................6-3

6.1.3 Vacating the Band....................................................................................6-5

6.2 Results for Individual Systems................................................................................6-5

6.2.1 Satellite Operations ..................................................................................6-5

6.2.2 Tactical Radio Relay................................................................................6-6

6.2.3 Air Combat Training Systems..................................................................6-9

6.2.4 Tactical Control Links/Precision Guided Munitions ...............................6-10

6.2.5 Other Systems ..........................................................................................6-11

6.3 Alternate Bands.......................................................................................................6-13

Appendix A – IMT-2000 System Description

Appendix B – Potential Interference to and from Satellite Operations

Appendix C – Potential for Sharing between IMT-2000 and Tactical Radio Relay in the

1755-1850 MHz Frequency Band

Appendix D – Potential for Interference between IMT-2000 Environment and Air Combat

Training Systems (1755-1850 MHz)

Appendix E – Other Systems

Appendix F – Mobile Video/Control Links (separately bound)

Appendix G – Discussion of Mitigation Methods

Attachment 1

Tables

3-1. Examples of DoD Systems Operating in the 1755-1850 MHz Band..........................3-2

6-1. DoD Cost and Schedule Summary (TY$B) ................................................................6-2
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GLOSSARY

3G Third-Generation

A/A Air-to-Air

A/G Air-to-Ground

AAPG Aircraft Inter-Antenna Propagation with Graphics

AAU Alaska Upgrade

AAW Anti-Air Warfare

ACC Air Combat Command

ACE Army Corps of Engineers

ACMI Air Combat Maneuvering Instrumentation

ACTS Air Combat Training System

ACUS Army Common User System

ADT Applied Data Technology

AEHF Advanced Extremely High Frequency

AFB Air Force Base

AFFMA Air Force Frequency Management Agency

AFS Air Force Station

AFSATCOM Air Force Satellite Communications System

AFSCN Air Force Satellite Control Network

AFSPC Air Force Space Command

AFWTF Atlantic Fleet Warfare Training Facility

AGM-130 Air-to-Ground Missile 130

AIS Airborne (or Aircraft) Instrumentation Subsystem

AISI Airborne (or Aircraft) Instrumentation Subsystem Internal

AISI(K) Airborne (or Aircraft) Instrumentation Subsystem Internal Encrypted

AM Amplitude Modulated

AMRAAM Advanced Medium Range Air-to-Air Missile

ANGB Air National Guard Base

ARSR Air Route Surveillance Radar

ARTS Automated Remote Tracking Stations

ATC Aberdeen Test Center

ATM Aeronautical Telemetry

AW/NTC-IS Air Warrior/National Training Center Integration System

AWACS Airborne Warning and Control System

BAS Broadcast Auxiliary Service

BBA-97 Balanced Budget Act of 1997

BER Bit Error Rate

BG Battlegroup

BPSK Binary Phase Shift Keying

BRH Beyond Radio Horizon
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C/NOFS Communications/Navigation Outage Forecast System

C2 Command and Control

C3 Command, Control, and Communications

CAIG Cost Analysis Improvement Group

CATF Commander Amphibious Task Force

CBRNE Chemical, Biological, Radiological, Nuclear and High Yield Explosives

CDMA Code Division Multiple Access

CEC Cooperative Engagement Capability

CEP Cooperative Engagement Processor

CFR Code of Federal Regulations

CIDDS Combat Identification for the Dismounted Soldier

CJTF Commander Joint Task Force

CLF Commander Landing Force

Combat ID Combat Identification

COMSEC Communication Security

CONUS Continental United States

COTS Commercial-off-the-Shelf

CSEL Combat Survivor/Evader Locator

CTS Colorado Tracking Station

CU Cooperating Unit

CWCS Countermeasures Warning and Control System

DAMA Demand Assigned Multiple Access

dB Decibel

dBHz Decibel Hertz

dBi Decibel Above Isotropic

dBm Decibel Above a Milliwat

dBW Decibel Above a Watt

dBW Decibel Above a Watt per Hertz

DDS Data Distribution System

deg Degree

DISN Defense Information Services Network

DLT Data Link Terminal

DME Distance Measuring Equipment

DMSP Defense Meteorological Satellite Program

DoC Department of Commerce

DoD Department of Defense

DoE Department of Energy

DQPSK Differential Quadrature Phase Shift Keying

DRRTS Dynamically Reconfigured Real Time Software

DS Direct Sequence

DSCS Defense Satellite Communications System

DSN Deep Space Network

DSP Defense Support Program

DTED Digitized Terrain Elevation Data
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DWTS Digital Wideband Transmission System

E&MD Engineering and Manufacturing Development

EAC Echelons Above Corps

ECAC Electromagnetic Compatibility Analysis Center

ECB Echelons Corps and Below

EDGE Enhanced Data Rates for GSM Evolution

EES Earth Exploration Satellite

EHF Extremely High Frequency

EIRP Effective Isotropic Radiated Power

EMC Electromagnetic Compatibility

EME Electromagnetic Environment

EMI Electromagnetic Interference

ENG Electronic News Gathering

EVCF Eastern Vehicle Checkout Facility

EW Electronic Warfare

FAA Federal Aviation Administration

FARP Fighter Advanced Readiness Program

FCC Federal Communications Commission

FDR Frequency-Dependent Rejection

FDRCAL Frequency-Dependent Rejection Calculation

FEC Forward Error Correction

FLTSAT Fleet Satellite Communications

FM Frequency Modulated

FPA Federal Power Agency

FRRS Frequency Resource Record System

FRS Fleet Replacement Squadron

FSK Frequency Shift Keying

G/A Ground-to-Air

G/G Ground-to-Ground

G/T Gain-to-Temperature Ratio

GA Ground Antenna

GBS Global Broadcast Service

GBU Guided Bomb Unit

GCCS Global Command and Control System

GCCS-M Global Command and Control System – Maritime

GCS Ground Control System

GEOSAT Geostationary Satellite

GFO GEOSAT Follow-On

GHz Gigahertz

GMF Government Master File

GMSK Gaussian Minimum Shift Keying

GOES Geostationary Operational Environmental Satellite
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GPRS General Packet Radio Service

GPS Global Positioning System

GRDCS Gulf Range Drone Control System

GSM Global System for Mobile Communications (or Groupe Speciale Mobile)

GTS Guam Tracking Station

HCLOS High Capacity Line of Sight

HNA Host Nation Agreement

HP High Power

HPA High Power Amplifier

HTS Hawaii Tracking Station

Hz Hertz

I/N Interference-to-Noise Ratio

ID Identification

IDN Instrumentation Datalink Network

IEEE Institute of Electrical and Electronics Engineers

IF Intermediate Frequency

IITRI Illinois Institute of Technology (IIT) Research Institute

IMT-2000 International Mobile Telecommunications for the Year 2000

INMARSAT International Maritime Satellite

IR Infrared

ISEM Inverse Smooth Earth Model

ISM Industrial, Scientific, and Medical

ISR Intelligence, Surveillance, and Reconnaissance

ISYSCON Integrated System Control

It Interference Threshold

ITCS Integrated Target Control System

ITFS Instructional Television Fixed Service

ITU International Telecommunication Union

ITU-R ITU Radiocommunication Sector

ITU-T ITU Telecommunication Standardization

J/F 12 DD Form 1494, Application for Equipment Frequency Allocation

JSC Joint Spectrum Center

JTCTS Joint Tactical Combat Training System

JTF-CS Joint Task Force – Civil Support

JTIDS Joint Tactical Information Distribution System

JTRS Joint Tactical Radio System

kb/s Kilobits per Second

kbps Kilobits per Second

ksps Kilosymbols per Second

kHz Kilohertz

km Kilometer
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LAMPS Light Airborne Multipurpose System

LAN Local Area Network

LEO Low-Earth-Orbit

LEO&A Launch, Early Orbit Operations and Anomaly Resolution

LOS Line of Sight

LP Low Power

LPD Low Probability of Detection

LPE Low Probability of Exploitation

LPI Low Probability of Intercept

LRIP Low-Rate Initial Production

m Meter

MB Mainbeam

Mb/s Megabit per second

Mbps Megabit per second

MCAS Marine Corps Air Station

MCC Mission Control Complex

MCEB Military Communications-Electronics Board

MCS Master Control Station

MDS Multipoint Distribution Service

MEF Marine Expeditionary Force

MEO Medium Earth Orbit

MHz Megahertz

MMDS Multichannel Multipoint Distribution Service

MOD Modified

MS Master Station or Monitor Station

MSE Mobile Subscriber Equipment

MSK Minimum Shift Keying

MSX Midcourse Space Experiment

MTACS Multi-Object Tracking and Control System

MTC Major Training Center

MUOS Mobile User Objective System

MW Microwave

MW Milliwatt

NAS Naval Air Station

NASA National Aeronautics and Space Administration

NATO North Atlantic Treaty Organization

NAVAIR Naval Air Systems Command

NAVSOC Naval Satellite Operations Center

NAWCAD Naval Air Warfare Center Aircraft Division

NB Narrowband

NCA National Command Authorities

NDAA-99 National Defense Authorization Act of 1999
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NDAA-00 National Defense Authorization Act of 2000

NDI Non-Developmental Item

NDS Nuclear Detonation Detection System

NF Noise Figure

NHS New Hampshire Station

NIMA National Imagery and Mapping Agency

nmi Nautical Miles

NOAA National Oceanic and Atmospheric Administration

NPOESS National Polar-Orbiting Operating Satellite System

NPRM Notice of Proposed Rulemaking

NRZ Non-Return-to-Zero

NRZ-L Non-Retrun-to-Zero-Level

NSAWC Naval Strike and Air Warfare Center

NTIA National Telecommunications and Information Administration

NUDET Nuclear Detonation

OAS Onizuka Air Station

OBRA-93 Omnibus Budget Reconciliation Act of 1993

OC Operational Center

OCONUS Outside the Continental United States

OOBE Out-of-Band Emissions

OQPSK Offset Quadrature Phase Shift Keying

OSD Office of the Secretary of Defense

PAM Pulse Amplitude Modulation

PCM Pulse Code Modulation

PCS Personal Communications Services

PGM Precision Guided Munitions

PM Phase Modulation

PSK Phase Shift Keying

QPSK Quadrature Phase Shift Keying

R&D Research and Development

RF Radio Frequency

RFI Radio Frequency Interference

RHCP Right Hand Circular Polarization

RPV Remotely Piloted Vehicle

RS Reed-Solomon

RTS Remote Tracking Station

RTT Radiotransmission Technology

Rx Receiver

S/(I+N) Signal-to-Interference plus Noise Ratio

S/N Signal-to-Noise Ratio
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SA Situation Awareness

SAR Search and Rescue

SATCOM Satellite Communications

SATOPS Satellite Operations

SBIRS Space-Based Infrared System

SCADA Supervisory Control and Data Acquisition

SCT Single Channel Transponder

SEM Spherical Earth Model

SFARP Strike-Fighter Advanced Readiness Program

SGLS Space Ground Link Subsystem

SL Sidelobe

SLAM-ER Standoff Land Attack Missile – Expanded Response

SMC/TE Space and Missile Center/Test and Evaluation

SOH State of Health

SRI Stanford Research Institute

SS Spread Spectrum

STDN Space Tracking and Data Network

STGS S-band Transportable Ground Station

STS Space Transportation System

SV Space Vehicle

T&E Test and Evaluation

TACAN Tactical Air Navigation

TACTS Tactical Air Combat Training System

TAS Target Acquisition System

TCM Trellis Coded Modulation

TCTS Tactical Combat Training System

TCU Tracking and Communications Unit

TDMA Time Division Multiple Access

TIREM Terrain Integration Rough Earth Model

TIS Tracking Instrumentation Subsystem

TOC Tactical Operations Center

TOSS Television Ordnance Scoring System (TCM-601)

TRI-TAC Tri-Services Tactical Communications

TRR Tactical Radio Relay

TST Transportable S-band Terminal

TSTR Transportable Space Test and Evaluation Resource

TSV Thru Site Video

TT&C Telemetry, Tracking, and Commanding

Tx Transmitter

TY$ Then Year Dollars

TY$B Then Year Dollars in Billions

TY$M The Year Dollars in Millions

UAV Unmanned Aerial Vehicle
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UFO UHF Follow-On

UHF Ultra High Frequency

US United States

US&P United States and Possessions

USB Unified S-band

USJFCOM United States Joint Forces Command

USMC United States Marine Corps

USNDS United States Nuclear Detonation Detection System

VTS Vandenburg Tracking Station

W Watt

WARC-92 World Radiocommunication Conference of 1992

WB Wideband

WCDMA Wideband Code Division Multiple Access

WGS Wideband Gapfiller Satellite

WLAN Wireless Local Area Network

WMD Weapons of Mass Destruction

WRC 2000 World Radiocommunication Conference for Year 2000

WSMR White Sands Missile Range
DoD IMT-2000 Assessment

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1.0 INTRODUCTION

1.1 BACKGROUND

In recent years, mobile wireless telecommunications systems have experienced a growth that is matched

by few other technologies. Large-scale mobile wireless common carrier services began with cellular

systems, sometimes referred to as first-generation systems. Subsequently, second-generation systems,

Personal Communications Services (PCS), provided many enhancements to cellular-type service.

Advances in technologies have led to the development of advanced wireless technologies, sometimes

referred to as third-generation (3G) services or International Mobile Telecommunications for the Year

2000 (IMT-2000). Recently, the World Radiocommunication Conference 2000 (WRC 2000) identified

several frequency bands that administrations are urged to consider when developing additional advanced

mobile communications services.

The frequency bands identified by WRC 2000 to support advanced mobile communications services

include, but are not limited to, 698-960 MHz, 1710-1885 MHz, and 2500-2690 MHz. In the United

States (US), a Presidential memorandum mandated that the IMT-2000 studies focus on the two higher

frequency bands. However, 1755-1850 MHz is allocated exclusively to Government Fixed and Mobile

Services. Many Executive Branch agencies make substantial use of the 1755-1850 MHz frequency

range for fixed and mobile operations. Without question the predominant single user of the 1755-1850

MHz band is the Department of Defense (DoD).

The DoD employs the 1755-1850 MHz band to support a broad range of critical mobile/transportable

systems, all DoD space systems, a large number of installation infrastructure services, as well as

advanced wireless systems in development that are aimed at providing capabilities to support 21st

century US warfighting. Major functions supported in the band include Satellite Operations (SATOPS),

Tactical Radio Relay (TRR), Air Combat Training System (ACTS), Tactical Control Links/Precision

Guided Munitions (PGMs), and other systems. Specific systems include, but are not limited to, the

Space Ground Link Subsystem (SGLS) which provides launch, deployment, and telemetry, tracking and

commanding (TT&C) of vital military satellite systems, Mobile Subscriber Equipment (MSE) and

Digital Wideband Transmission System (DWTS) which support tactical communications, and the Air

Combat Training Systems (ACTS) and the Joint Tactical Combat Training System (JTCTS) used to

support air combat training.

In an October 2000 Memorandum, the President directed federal agencies to participate and cooperate in

the activities of a government-industry effort (led by the Secretary of Commerce in cooperation with the
DoD IMT-2000 Assessment

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Federal Communications Commision (FCC)) to identify spectrum for 3G. As part of this effort, federal

agencies have been asked to examine their use of the 1755-1850 MHz frequency band and to assess the

prospects for sharing spectrum with IMT-2000 systems. The DoD is complying with this request by

identifying all DoD systems that operate in the band of interest, assessing the technical feasibility of

sharing, examining the operational impact of sharing and/or relocation, and quantifying cost issues

associated with sharing and/or relocation. This report presents an assessment of the issues associated

with sharing and/or relocation by examining technical, operational, and cost issues associated with

selected DoD systems and several notional candidate IMT-2000 systems. While there is commercial

interest in worldwide deployment of IMT-2000 services, the focus of this effort was primarily sharing

issues in the US and possessions (US&P).

1.2 OBJECTIVE

The objective of this effort was to perform an assessment of technical, operational, and cost issues

associated with incumbent DoD systems in the US&P and the possible introduction of IMT-2000 mobile

wireless systems into the 1755-1850 MHz frequency band.

1.3 APPROACH

The approach used in this effort employed multiple steps to develop a final integrated product with

technical, operational, and cost assessments. The initial step was to identify DoD radio frequency (RF)

systems that operate in any or all of the 1755-1850 MHz band. The next step was to conduct technical

analyses to determine the potential for undesired interactions between DoD systems and IMT-2000

systems. The results of these analyses were then assessed for several band

sharing/segmentation/vacating scenario options, as described below. Based on the technical interference

analysis results and considering each scenario option, DoD elements responsible for using the various

systems defined the operational impacts of accommodating IMT-2000 systems into the 1755-1850 MHz

band. The final step involved the determination of cost impacts to DoD systems for each of the specific

accommodation scenarios.

The first step of identifying all DoD RF systems operating in the subject band was accomplished as

follows. An extensive survey was conducted of DoD spectrum management databases to identify all

DoD systems with the capability to operate in any portion of the band. Once systems were identified,

the “owning” military department was tasked to verify with operational and acquisition/support

commands the life-cycle status of the system (operational, obsolete, being replaced, etc.). The final list

of valid systems (operational or funded for production) became the basis of all subsequent study efforts.
DoD IMT-2000 Assessment

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In addition to building the list of valid systems, the DoD also collected technical and operational data on

each of the systems. This information included system radio frequency (RF) waveforms, transmitter

parameters, system losses, antenna patterns, antenna pointing angles, siting data, receiver selectivities,

and receiver performance criteria. Operational data included such information as geographical

locations, link lengths, and platform operating altitudes. Planned system upgrades were also

incorporated if available technical data was sufficient to support proper electromagnetic compatibility

(EMC) assessments.

The next step was to conduct the engineering analyses of the interactions of DoD systems and IMT-2000

systems. Technical parameters for the RF systems were used, and likely operational scenarios were

defined. Then desired and interfering signal levels were predicted at the receivers of interest, and

predictions were made with respect to the likelihood of undesired interactions. If undesired interactions

were predicted, then distance and/or frequency separations required to prevent interference were

calculated. In addition to frequency/distance separations, other potential means to mitigate interference

were also identified. The unique aspects of specific system interactions are discussed in the appendices.

In order to conduct the technical interference analyses described above, two interim steps were required.

The first interim step was to determine the specific technical parameters for IMT-2000 systems that

would be used in the EMC assessments. Since there is no IMT-2000 hardware in production in the US

at this time, it was necessary to develop the parameters for the analysis using technical literature,

selected aspects of existing wireless mobile systems, and calculations based on communications theory.

The basis for the final parameters used in the assessments was a Federal Communications Commission

(FCC) document presenting notional characteristics for various technologies that may be used to

implement IMT-2000 services.1

 Minor modifications were made to the FCC parameters following

discussions between the FCC and DoD technical staffs. The IMT-2000 technical parameters used are

presented in Appendix A.

The second interim step necessary to enable the accomplishment of the technical interference analyses

was the grouping or clustering of the large number of DoD systems into subsets referred to as “major

systems categories.” This grouping of systems was necessary for several reasons. There were over two

hundred systems identified as potentially being impacted by the accommodation of IMT-2000 systems

in the subject band. The study schedule did not allow sufficient time to conduct individual EMC

assessments for each of these systems. In addition to the time constraint factor, a number of the systems

 

1 Spectrum Study of the 2500-2690 MHz Band: The Potential for Accommodating Third Generation Mobile Systems,

Interim Report, FCC, 15 November 2000.
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were similar in both mission function and technical capabilities and that a technical interference analysis

conducted for one system would be useful in drawing conclusions for multiple similar systems. Lastly,

the grouping of systems into logical categories would facilitate the development of a high-level set of

study conclusions that would be much more useable for the national decision process. The major

categories of systems used for the study follow:

• Space/SGLS systems

• Tactical radio relay systems

• Air Combat Training Systems

• Precision Guided Munitions systems

• Miscellaneous “Other” systems

Once the technical analysis results were available for each of the major system categories, they were

used to assess the “technical” feasibility of the DoD systems operating in the 1755-1850 MHz band to

accommodate new IMT-2000 systems. The 3G-study plan developed in response to the Presidential

Memorandum of October 13, 2000 provides that the FCC and the National Telecommunications and

Information Administration (NTIA) will address band segmentation and sharing options. The following

options were assessed in this DoD impact study.

• Option 1: Full band sharing (IMT-2000 systems operating anywhere in the 1755-1850 MHz

band)

• Option 2: Band segmentation/Partial Band sharing

− 1755-1805 MHz retained for operation of government systems and 1805-1850 MHz

potentially reallocated to non-government use (Option 2A)

− 1790-1850 MHz retained for operation of government systems, and 1755-1790 MHz

potentially reallocated to non-government use as part of a phased sharing approach

(1710-1755 MHz available immediately, 1755-1780 MHz available at some mid-term future

date, and 1780-1790 MHz would be made available in the long-term). (Option 2B)

• Option 3: Band segmentation and other band combination (Options 3A/3B)

• Option 4: Vacating the Band

The next major step was to identify the operational impacts of the various sharing segmentation options.

The results of the technical feasibility sharing analyses were provided to the military commands and

operational communities that employ the various systems in accomplishing national security missions.

These organizations were tasked to develop the operational impacts to their missions based on the
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technical results of each of the sharing scenarios, as well as for the potential scenario of total band loss.

The operational impacts for each scenario were also required to be assessed for the three time frames of

2003, 2006, and 2010. The operational impact is defined to be the change from current or planned

operational capability (to support combat operations or the ability to be fully prepared, through training

and testing, to support combat operations) to the reduced level of operational capability expected once

IMT-2000 systems are deployed. The reduced level of operational capability would include, but is not

limited to, the applicable effects of sharing, mitigation measures, and/or migration.

Following the technical and operational assessments by major system category, the next step was to

perform cost impact studies. These studies were required to address the costs of interference mitigation

measures as well as band migration measures for the major systems impacted by each of the sharing

scenarios. The cost impacts were developed by acquisition program offices with the participation of

operational command representatives and military Service costing organization representatives. To

ensure consistency in costing approaches, costing guidelines were provided for all cost efforts by the

Office of the Secretary of Defense (OSD) Cost Analysis Improvement Group (CAIG).

The results of each of the three primary assessment efforts, technical, operational, and cost; were then

integrated into a synthesized DoD assessment for each of the major system categories and in accordance

with the tasked framework of sharing/segmentation/vacating options and the three time periods (2003,

2006, and 2010).
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2.0 ESSENTIAL CONDITIONS

The 1755-1850 MHz frequency range supports several functions critical to the DoD mission and the

security of the US. The compromise of any of these functions is unacceptable. Congress has recognized

the importance of adequate access to radio spectrum to the DoD mission and the security of the US and

has enacted legislation to provide particular protections. In particular, the National Defense

Authorization Act of 2000 (NDAA-00) directs that DoD shall not surrender use of a band of frequencies

of which it is a primary user unless (a) NTIA, in consultation with the FCC, has identified and made

available to the DoD for its primary use, if necessary, an alternative band or bands of frequencies with

comparable technical characteristics as a replacement, and (b) the Secretary of Commerce, the Secretary

of Defense, and the Chairman of the Joint Chiefs of Staff have jointly certified to the Committee on

Armed Services and the Committee on Commerce, Science and Transportation of the Senate; and the

Committee on Armed Services and the Committee on Commerce of the House of Representatives, that

the replacement band or bands of frequencies identified in (a) above provides comparable technical

characteristics to restore essential military capability that will be lost when the band of frequencies is

surrendered. The following general conditions cannot be compromised during the consideration of this

band.

• If a decision is made to vacate all or a part of the 1755-1850 MHz band, the DoD must retain

protected access until the last DoD system has migrated. Current regulatory provisions that

protect existing DoD operations in the band must continue throughout any migration or transition

period.

• DoD must be provided regulatory protection in any new band associated with a reallocation

action equivalent to the protection currently provided in the 1755-1850 MHz band.

• DoD systems moving to a new band must receive timely domestic spectrum certification and

have reasonable prospect of achieving international coordination consistent with mission

requirements.

• During any transition period in which DoD is moving out of the band or a portion thereof, new

users would be allowed to operate in the band only to the extent that their operations do not

interfere with DoD operations.

• Timely cost reimbursement must be provided to the DoD per NDAA 1999.
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• Schedules associated with Program execution cannot be altered.

• Time is a critical factor and at least a decade will be required to implement any changes.

2.1 CONDITIONS FOR SATELLITE OPERATIONS

This report is based on the following conditions with respect to transition or migration of space

operations from the 1755-1850 MHz to 2025-2110 MHz band.

• Mission capability provided to end users by US national security space systems will not be

degraded. The government will maintain assured access to the 1755-1850 MHz band to satisfy

mission objectives until the last 1755-1850 MHz satellite is no longer functioning. This may

continue until 2030.

• Domestic regulatory provisions will be implemented so that the DoD has assured access to the

2025-2110 MHz band for Launch, Early Orbit Operations and Anomaly Resolution (LEO&A)

and other operations currently operating in the 1755-1850 MHz band. Specifically, the

Broadcast Auxiliary Service (BAS) or Electronic News Gathering (ENG) services at

transportable and mobile locations shall not claim protection from DoD operations which have

been migrated to the 2025-2110 MHz band.

• Current domestic regulatory provisions that protect existing DoD operations in the 1755-1850

MHz band shall continue throughout any spectrum operations migration/transition period.

• DoD obtains appropriate regulatory protections approved national frequency spectrum

certifications and assignments in the 2025-2110 MHz band consistent with mission requirements

and acquisition timelines.

• The US concludes successful international coordination of DoD satellite networks in the

2025-2110 MHz band.

• DoD determines it is actually possible to successfully conduct satellite command and control

operations in the 2025-2110 MHz band.

2.2 CONDITIONS FOR AIRBORNE AND TERRESTRIAL SYSTEMS

The following conditions apply to all other systems with respect to transition or migration from the

1755-1850 MHz frequency band to any other frequency band.

• Mission capabilities provided to military end users will not be degraded. The government will

maintain assured access to the 1755-1850 MHz band to satisfy mission objectives until any
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capability supported by the 1755-1850 MHz band is successfully accommodated with equivalent

regulatory protection in a new frequency band.

• Current domestic regulatory provisions that protect existing DoD operations in the 1755-1850

MHz band shall continue throughout any spectrum migration/transition period.

• DoD obtains appropriate regulatory protections approved national frequency spectrum

certifications and assignments in any new frequency bands consistent with the mission

requirements and acquisition timelines of affected systems.
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3.0 SYSTEM DESCRIPTIONS

3.1 IMT-2000 SYSTEM DESCRIPTION

IMT-2000 and 3G services are the names commonly used to refer to advanced or next-generation

mobile wireless telecommunications services. Commercial interests have generally agreed that the 3G

family of services, and the systems that will provide them, are intended to reflect a high degree of

commonality and are to be compatible with each other. These services will support mobile and fixed

users employing a wide range of devices including small pocket terminals, handheld telephones, laptop

computers, and fixed-receiver equipment. Some commercial interests envision the 3G services to be

ubiquitous throughout the globe, as available in a remote part of a developing country as they are in an

urban area in a highly developed country. These entities believe there are significant benefits to

manufacturers and users of wireless systems to seamless roaming on a regional and global scale, hence

the desire for standardization in system design and service provision for 3G services. The detailed

technical parameters of IMT-2000 systems used in this assessment are contained in Appendix A.

3.2 DOD SYSTEM DESCRIPTIONS

The DoD has received spectrum certification for hundreds of communications-electronics systems in the

1755-1850 MHz frequency range and operates many thousands of these systems in the US and abroad.

Each of the military services has major, critical systems in this frequency band, as well as important

local systems for command and control, security, telemetry, target scoring, video links, and a variety of

other functions. This frequency range is used by these critical DoD systems due to a number of factors.

The propagation characteristics of the band enable reliable links with low power and low losses as well

as excellent penetration of foliage. The band provides wide beamwidths for quick path alignment,

inherently allows for inexpensive system components, enables simple equipment set-up methods, and

supports highly mobile applications. Table 3-1 identifies some of the major systems and the functions

the systems support.

Within the time and resources available for this assessment it was not possible to address all of the DoD

systems certified to operate in the 1755-1850 MHz band. Several critical systems were selected for the

assessments to help establish the scope of compatibility issues associated with the possible sharing of

the frequency band. Overviews of these systems are provided below. Detailed descriptions and the

technical parameters used in the assessments are presented in the associated appendix.
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Table 3-1. Examples of DoD Systems Operating in the 1755-1850 MHz Band

System Name Function

Space Ground Link Subsystem Satellite telemetry, tracking, and command

Some Typical Satellite Systems

 GPS

 Milstar

 Defense Meteorologica Satellite Program (DMSP)

 Defense Support Program (DSP)

 Navigational and Precise Time Data

 Satellite Communications

 Meteorological, oceanographic

 Missile launch detection

AN/GRC-103 Tactical radio relay

AN/GRC-226 Tactical radio relay

AN/GRC-245 Tactical radio relay

AN/MRC-142 Tactical radio relay

AN/SRC-57 Tactical radio relay

Tactical Air Combat Training System Air combat training

Air Force ACTS Air combat training

Joint Tactical Combat Training Systems Air combat training

Tactical Control Links/PGM Control of precision strike weapons

Land Warrior Wireless local area network for combat troops

AN/DSQ-37 Target scoring system

Combat Identification (ID) for the Dismounted Soldier Tactical communications

Intrusion Detection System Perimeter security

Robotics Control System Wireless remote control

3.2.1 Satellite Operations (SATOPS)

The DoD uses this band as the only communications link for initial contact with newly launched

satellites, for early orbit checkout of those satellites and for emergency access to spinning/tumbling

satellites. It is also vital for command and control, mission data retrieval, navigational data uploads for

GPS, and on-orbit maneuvering of its many satellites in all orbits from low earth to geostationary. The

SGLS, the primary component of this network, provides continuous, worldwide, command and control

of satellites used for missile warning, navigation, military communications, weather tracking and

reporting, and intelligence, surveillance, and reconnaissance (ISR). The information provided by these

satellites to our National Command Authority, Combatant Commanders, Military Services, and national

level decision-makers is crucial to successful execution of our national strategies. Additionally, other

federal government agencies, such as the Federal Aviation Administration (FAA), the National

Aeronautics and Space Administration (NASA), the Federal Emergency Management Agency, state and

local governments and the commercial sector benefit from the capabilities of the satellites controlled by

this network.
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3.2.2 Tactical Radio Relay

The Army, Navy, and Marine Corps operate tactical communications systems in this frequency band

providing high capacity, digital information to the battlefield. These systems are described below.

3.2.2.1 Mobile Subscriber Equipment (MSE)

The AN/GRC-103, AN/GRC-226, and AN/GRC-245 Radio Sets are line-of-sight (LOS) trunk radios

used to link nodes (switching centers) in the Army’s tactical telecommunications system or the Army

Common User System (ACUS). These radios operate in the 1755-1850 MHz spectrum band. The

ACUS is a seamless, tactical communications system that provides secure, highly reliable voice and data

communications for both mobile and fixed elements in a tactical or battlefield environment. The ACUS

operates from the front-line maneuver battalions to theater headquarters in rear areas. This

communication network is formed in two parts: the MSE and the Tri-Services Tactical Communications

(TRI-TAC) system. The MSE system is deployed from the corps-level headquarters to the maneuver

battalions and the TRI-TAC system is deployed from corps-level headquarters to higher levels of

command. These systems provide a digital microwave backbone to link mid level and lower level

battlefield commanders with upper level theater decision-makers. The system operates like a highcapacity PCS with rapidly transportable base stations. A corps-size deployment could deploy twelve or

more microwave links depending on the operational or exercise scenario. From command and control

traffic to intelligence imagery, logistics, medical, and morale and welfare support, MSE provides the

battlefield commanders the ability to maintain effective control over their forces. MSE is a tactical

system designed for rapid deployment in the field. This is because headquarters units, with their

signature electronic emissions, are targeted for artillery and missile attacks by the enemy. The ability to

set up, establish a link to higher headquarters and subordinate units and then take the link down and

move is key to the survivability of the headquarters units and supports the concept of maneuver warfare.

The microwave radio equipment and antennas are transportable and robust for field conditions. To

maintain the operator’s capability to quickly establish a tactical microwave link, continuous field

training is required.

3.2.2.2 Digital Wideband Transmission System (DWTS)

The Navy/Marine Corps DWTS provides a backbone digital communications capability supporting

amphibious operations and ground combat operations. The system supports command, control and data

transfer from the Marine Expeditionary Force (MEF) level down to the regimental level. The AN/MRC142 is the Marine Corps element of this radio system providing the digital backbone services (voice,
DoD IMT-2000 Assessment

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video and data). This link is the only transmission media available to the Marine Corps with sufficient

bandwidth to carry large quantities of critical data such as maps, overlays, intelligence pictures, and

other data to the battlefield commanders. The Navy ship-to-shore link of DWTS is the AN/SRC-57

radio. This link is essential for amphibious operations where most of the critical information flow is

from the ship to the landing forces. Like ACUS/MSE, DWTS is a tactical system designed to quickly

establish microwave links in support of combat operations and maneuver warfare.

3.2.3 Air Combat Training Systems (ACTS)

3.2.3.1 Tactical Air Combat Training System/Aircrew Combat Maneuvering and

Instrumentation (TACTS/ACMI)

TACTS/ACMI is a complex system of hardware and software components configured and interfaced to

measure, monitor, process, communicate, store, and display weapon and aircraft information in real-time

to provide realistic training for tactical aircrews. The US Air Force uses ACMI while TACTS supports

the US Navy and Marine Corps. TACTS/ACMI is comprised of airborne and ground-based components

linked through RF communications and operates within many prescribed training ranges in the US. The

TACTS/ACMI supports training aircrews in realistic warfighting scenarios. It supports simultaneous

engagement of multiple air combat participants in state-of-the-art air-to-air, air-to-ground, ground-to-air,

and electronic warfare (EW) environments. The system provides real-time monitoring, tracking and

recording of the training activities and includes post mission reconstruction capabilities so that crews

can receive accurate debriefing and critique of their mission thereby maximizing the benefit of the

training activities. The system provides aircrew training such as Aircraft Handling Capability, Basic

Fighter Maneuver, or Intercept and Air Combat Training sorties up to and including large composite

force training. TACTS/ACMI is the primary tool at virtually all air combat training ranges and supports

every level of training from initial schools where pilots first learn to fly the aircraft they will take into

battle to advanced tactics training schools that hone combat skills. Typical training bases, such as Luke

AFB, AZ, can average 200-plus sorties a day on their instrument range. To ensure interoperability,

training sorties are also conducted with Allied Forces, both inside and outside of the US.

3.2.3.2 Joint Tactical Combat Training System (JTCTS)

JTCTS is being developed as the next generation of aircrew training system. JTCTS will fulfill the same

functions as TACTS and will provide added flexibility to support “rangeless” training that the current

TACTS and certain ACMI systems cannot. JTCTS will employ the GPS for position determination,

thereby reducing the requirements for ground support infrastructure and allowing training to be
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accomplished without the need for a robust system of ground reference stations. The current JTCTS

development program is being restructured due to technical issues. When finished, JTCTS will support

more robust inter-service training, as the Services become more interdependent.

3.2.4 Tactical Control Links/Precision Guided Munitions

Tactical Control Links that support PGMs, like the Navy/Marine Corps Standoff Land Attack MissileExpanded Response (SLAM-ER) and the Air Force Air-to-Ground Missile-130 (AGM-130) and Guided

Bomb Unit 15 (GBU-15), provide a decisive combat edge to US forces. These weapons provide the

capability to attack single targets with one aircraft or one standoff weapon with greater probability of

success than by flying waves of aircraft dropping iron bombs. PGMs increase aircrew survivability by

allowing the launch of weapons outside of any enemy anti-air system threat envelope, thereby

significantly decreasing aircrew vulnerability. PGMs require regular testing and training in the

continental US (CONUS) sites by operational units to maintain operational readiness. Developmental

activities also require regular testing as the PGMs are updated for new missions, threats, and

capabilities. As documented in air campaigns such as those conducted in Iraq and Kosovo, PGMs were

key in the destruction of high value and highly defended targets with little or no collateral damage and

aircraft losses. The combatant commanders require this capability to successfully accomplish any

mission requiring the use of force.

3.2.4.1 SLAM-ER

The SLAM-ER program builds on the existing Harpoon and baseline SLAM weapon systems. SLAM is

a fielded system with proven combat performance in Operation Desert Storm and Bosnia, while SLAMER is intended to provide dramatic weapon system performance improvements. The benefits gained

from this retrofit are doubled flight range, communications range, and warhead penetration; improved

lethality, countermeasures resistance, target coverage, aimpoint selectivity, and accuracy; with a much

simpler mission planning and cockpit interface. SLAM-ER has provisions to store up to three preplanned missions, including Automatic Target Acquisition missions, and one Target of Opportunity

mission. Pre-planned missions are developed for fixed land targets or ships in harbor. Pre-planned

missions take into account known defenses and terrain. Target of Opportunity missions are generally

used for relocateable targets in both land attack missions and Anti-Surface Warfare ships-at-sea

missions.
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3.2.4.2 AGM-130 & GBU-15

In particular, the AGM-130 and GBU-15 precision guided weapons2 were designed for employment

against fixed, high-value targets in all weather conditions, day or night. These weapons, in the 2000-

pound class of weapons, are launched from F-15E aircraft from either low or high altitude at ranges

from 5 to in excess of 30 nautical miles. Equipped with TV or Infrared sensors and aided by GPS, these

weapons provide operators the ability to attack targets in all weather conditions, day or night. These

weapons can be controlled from either the launch aircraft or a standoff aircraft at a range of more than

100 nautical miles. Operators require access to video and command link frequencies at any time during

the mission, including ground operations, post take-off pre-launch operations, and post-launch weapon

flight operations. Access to the RF spectrum is critical during all training and testing operations-these

operations require use of the frequencies for two hours per mission.

3.2.5 Other Systems

The operations of a number of additional DoD systems rely on spectrum between 1755 and 1850 MHz

in addition to those of the four primary DoD functional capabilities. Long-range point-to-point

microwave system operations represent a majority of the systems. These systems primarily operate at

fixed locations and employ directional antennas. A number of mobile operations are also authorized in

this band. Two mobile systems, the Combat Identification for the Dismounted Soldier (CIDDS) and the

Land Warrior Local Area Network (LAN), are developmental systems whose operations also are

dependent on spectrum in this band segment. Land Warrior is a first-generation integrated fighting

system for dismounted soldiers. A number of Unmanned Aerial Vehicles (UAVs) such as the Pointer

(FQM-151A) and the Exdrone (BQM-147A) are authorized to operate in this band. These systems

transmit video and status data from the UAV to the ground control system (GCS) using analog

frequency modulated (FM) video and data on subcarriers. Fixed point-to-point microwave, CIDDS, the

Land Warrior LAN, and UAVs are believed to represent significant other uses of the 1755 to 1850 MHz

band.

3.2.5.1 Corps of Engineers

The Army Corps of Engineers (ACE) operates a nation-wide system of fixed point-to-point microwave

links providing connectivity for monitoring water levels, remote alarms, and communications for remote

 

2 Case Study: Impact Assessment on Precision Strike Weapon Data Link Systems to Accommodate IMT 2000, Eglin

AFB, FL: USAF, 5 January 2001. This case study is provided as reference material with the electronic version of this

document.
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locks, dams, and other water systems. This system provides microwave links where no commercial

communications connectivity exists. This system is essential to the ACE operations because it allows

for remote monitoring of critical waterway operations negating the need for full time, on-site personnel.

The systems provide key maintenance parameters, alarm indications, and provide personnel at the

facility with communications capability. The system helps ensure the safety and integrity of the nation’s

waterways and helps prevent catastrophic events that could cost lives and economic damage as well as

environmental damage.

3.2.5.2 Land Warrior

The Land Warrior system is a close combat communications system for infantrymen, combat medics,

combat engineers, forward observers, and scouts. With Land Warrior, the soldier can both send and

receive voice, video images, map overlay information, operational plan diagrams, etc. The system

provides situation awareness information among all team members, improves survivability and increases

mission effectiveness while reducing the soldier’s equipment load. Current program documentation

indicates a minimum of 41,000 units, with a potential increase to 71,000 units, are to be produced

commencing in calendar year 2003.

3.2.5.3 Combat Identification of the Dismounted Soldier

The purpose of CIDDS is to help prevent friendly forces from firing on friendly forces, otherwise known

as fratricide. CIDDS employs a laser interrogator with an RF response to provide identification of

friendly forces by individual and automatic weapons users to a range of over 1000 meters, depending on

visual conditions. Forward combat forces, in both open terrain and urban areas, use the system. The laser

interrogation signal message identifies a set of random frequency channels, spaced throughout the 1755-

1850 MHz band for the transponder to use in its response. Current program documentation indicates

approximately 100,000 CIDDS units will be procured to outfit dismounted soldiers of all three military

services. CIDDS entered into development in 1997 and the low-rate initial production of fifty units will

be tested in FY01.

3.2.5.4 Pointer Unmanned Aerial Vehicle

The Pointer UAV is a production-ready, electric, hand-launched UAV designed for remote monitoring

and surveillance. The UAV transmits real time images taken by a black and white, color or thermal

camera. A variety of alternative payloads such as air pollution sensing, chemical weapons detection,
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and unexploded land mine detection are currently being developed. The video link operates in the 1755-

1850 MHz frequency band.

3.2.5.5 Aberdeen Test Center

The Aberdeen Test Center (ATC) Range Telemetry System provides a multi-link radio telemetry

communication capability throughout the many test ranges and facilities of the ATC. It consists of

several fixed receiving stations located at the high-usage ranges/test areas and many transportable

(vehicle housed) receiving stations which are employed at any of the multitude of ATC test areas or

remote test sites when required to support testing projects. The test mission and workload of the ATC

requires daily support by the telemetry system. It is vital to the accomplishment of the test and

evaluation of military equipment, primarily combat and tactical vehicles, and many items of support

equipment. Testing under dynamic conditions is a requirement, and the telemetry system provides the

capability to transfer engineering measurements from the moving vehicle to a data collection center.

3.2.5.6 Television Ordnance Scoring System (TOSS)

The TOSS (TCM-601) system provides a television ordnance scoring capability to range users in

support of exercise and test missions at Nellis Range. TOSS is a field proven accurate weapons scoring

system with a night scoring capability using infrared cameras. Scoring can be done for live or inert

conventional weapons.
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4.0 ASSESSMENT APPROACH

The approach used in this effort required multiple steps in order to develop a final integrated product

with technical, operational, and cost assessments. The initial step was to identify DoD RF systems that

operate in any or all of the 1755-1850 MHz band. The next step was to conduct technical analyses to

determine the potential for undesired interactions between DoD systems and IMT-2000 systems. The

results of these analyses were then assessed for several band sharing/segmentation/vacating scenario

options. Based on the technical interference analysis results and considering each scenario option, DoD

elements responsible for the various systems then defined the operational and cost impacts of

accommodating IMT-2000 systems into the 1755-1850 MHz band.

4.1 INTEGRATION OF TECHNICAL, OPERATIONAL, AND COST

ASSESSMENTS

The compilation and integration of the various technical, operational, and cost assessments for the

numerous DoD systems were based on the following approach. At the highest level, the integration

framework addressed each major system category (ACTS, Tactical Radio Relay Networks, etc.) by each

of the four sharing/segmentation/vacating scenarios. The key technical assessment results from each

element of this framework were integrated with any applicable programmatic realities with respect to

system life-cycle projections (expected phase-out, replacement or upgrade date, new system fielding

dates, etc.) and potential mitigation measures. For each of the major system categories and the various

sharing scenarios, the associated operational and cost assessments were then addressed. If the

operational and cost assessments varied over the time frames of 2003, 2006, and 2010, they were

included as distinct potential impact situations.

4.2 TECHNICAL ASSESSMENT APPROACH

The goal of this effort was to assess the potential for sharing in the 1755-1850 MHz frequency band

from a technical perspective. Assessments were two-way assessments in that analysts considered both

interference from DoD systems to IMT-2000 receivers and interference from IMT-2000 emitters to DoD

receivers. The general technical approach was to predict undesired signal power at victim receivers by

considering appropriate interfering transmitter parameters, operational configurations, coupling between

systems considering antenna orientations and propagation losses, and frequency-dependent rejection

when appropriate. Undesired received power levels and victim receiver interference thresholds were

then used to assess the potential for interference. Interference thresholds may be either interference-to-
DoD IMT-2000 Assessment

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noise ratios, desired signal-to-interference plus noise ratios, or the degradation of link margins needed to

sustain acceptable bit or symbol energy-to-noise power densities. Desired signal levels were either

calculated or provided by system users based on their experience with the design and use of the subject

system.

It was recognized that a number of the assessment parameters may not yet be finalized or may vary

depending on operational configurations. Consequently parametric assessments were performed in

many cases. Many of the appendices contain either multiple figures showing variations in signal levels

for different values of selected parameters or tables with multiple entries for similar reasons. Parameters

that may vary include, but are not limited to, transmitter power, antenna gain, antenna pointing angles,

antenna heights, data rates, receiver selectivities, and desired signal levels.

Implementation of the general technical approach had variations depending on the particular DoD

systems being considered. For example, in the satellite operations (SATOPS)-to-IMT-2000 assessment,

the primary SATOPS sites are fixed in locations. In this case, a terrain-dependent propagation model

could be used to establish received signal level contours around the SATOPS earth station sites for

various IMT-2000 base stations and mobile units. Multiple contours are provided in Attachment 1 to

reflect variations in receive system parameters and different SATOPS transmit powers and antenna

elevation angles.

In the case of mobile or transportable DoD systems, terrain-dependent propagation modeling was not

appropriate and a smooth-earth propagation model was used. Also in these cases, this initial assessment

tended to place mobile and transportable units at distance separations or altitudes that either reflected

guidance from the appropriate program office or represented communications links that would be

operating near minimally acceptable conditions. The latter approach is somewhat conservative and was

used principally to bound the limits of sharing issues. In several cases, sharing is investigated where

desired signal levels are significantly better than minimally acceptable levels. These cases are so noted

in the appendices.

Source-to-victim configurations also varied in the assessments. In some cases one-to-one assessments

were performed where the principal source of interference was a single emitter of one system to a single

receiver of a victim system. Examples of these cases include a single AN/MRC-142 radio to a single

IMT-2000 mobile receiver (Appendix C) and a single IMT-2000 base station emitter to a single ACTS

ground receiver (Appendix D). In other cases, assessments addressed many-to-one interactions.

Examples of these cases include multiple IMT-2000 emitters to spaceborne SGLS receivers
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(Appendix B) and multiple IMT-2000 emitters to DoD aircraft participating in training exercises

(Appendix E).

As reflected in the description of IMT-2000 systems, mobile wireless networks are deployed over the

period of several years. When appropriate, the assessments considered the notional build-out schedule

contained in Table A-7. Consideration of this schedule gives an approximate estimate of when certain

systems may be affected, as IMT-2000 networks are built-out in the US. These estimates are not precise

and may be subject to debate but they do identify those systems particularly sensitive to large-scale

network development such as airborne and spaceborne receivers.

4.3 OPERATIONAL IMPACT ASSESSMENT APPROACH

A four-step process was performed to conduct the operational impact assessment for the introduction of

IMT-2000 systems into the 1755-1850 MHz band. The first step was to define the system capabilities

and associated mission for each of the major systems. Subsequently, DoD analysts assessed system and

programmatic changes dictated by the possible introduction of IMT-2000 systems. The next step was to

develop and distribute a series of questions to assess system impact based upon a previously identified

set of operational scenarios and IMT-2000 phase-in schedules. These questions were sent to the

appropriate program offices, Services, and Combatant Commands. Finally, the responses were

compiled and analyzed.

The evaluation of operational impacts included an assessment of the effects resulting from changes to

operating parameters, or procedures, and possible changes to concepts of operation. The evaluation also

addressed the effects of radio frequency interference (RFI), RFI mitigation techniques employed, and

possible changes to system hardware and/or software.

The system impact assessments were based upon the introduction of IMT-2000 systems in years 2003,

2006, and 2010 for each of the four options identified in Section 1.3, i.e., full band sharing, band

segmentation, band segmentation and combination with other bands, and vacating the band.

4.4 COST ASSESSMENT APPROACH

To determine the cost of transitioning incumbent DoD systems to a new band or the cost of some other

means of interference mitigation to 3G systems, it was first necessary to develop a program management

plan for implementing the transition. Since DoD will not accept operational degradation caused by the

introduction of 3G systems, any proposed program plan must ensure current levels of operational
DoD IMT-2000 Assessment

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capability are maintained. Furthermore, any proposed plan must be realistic in the sense of execution,

schedule, and risk. Additionally, since little is known regarding availability and location of possible

bands that DoD could relocate its systems to, assumptions must be made in this regard to carry out the

costing activity. It should be recognized that the costs are sensitive to the band selected and, to the

extent that the assumptions made turn out not to be the case, the costing activity may require refinement.

The methodology used to develop the estimates for cost reimbursement follow generally accepted cost

estimation practices used within the DoD and is consistent with the approach to cost reimbursement

proposed in the NTIA’s Notice of Proposed Rulemaking (NPRM) on Mandatory Reimbursement Rules

for Frequency Band or Geographic Relocation of Federal Spectrum-Dependent Systems (published in

the Federal Register on January 17, 2001). The cost estimates developed are meant to be preliminary

and representative, however, not conclusive. The costs reflect estimated funding for the candidate

relocation bands and time frames assumed for relocation.
DoD IMT-2000 Assessment

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5.0 CRITICAL ASSUMPTIONS

The following assumptions were key to the assessment process and the study results.

5.1 OVERALL STUDY ASSUMPTIONS

• Equipment/system modifications or physical relocations to support sharing, segmentation, or

vacating the band would not occur by the 2003 time frame due to the time required for program

budgeting, and contract preparation, award, and execution.

• Scenarios were not considered feasible if they resulted in a degradation of operational capability

for DoD systems.

5.2 TECHNICAL ASSUMPTIONS

• Systems grouped into major system categories (except “Other”) demonstrate similar radio

frequency interactions with IMT-2000 systems.

• Transportable, mobile and airborne DoD systems are assumed to operate over the full geographic

area of their associated military installations (i.e., emitters could be located along the installation

boundary).

• Aggressive schedules for system modifications, upgrades, or replacements were considered high

risk and unlikely to be successful.

5.3 OPERATIONAL ASSUMPTIONS

• US Armed Forces are vital to the security of the US and require assured spectrum access to

perform their missions.

• The ability of US Armed Forces to conduct operations and train in the US is essential to

maintaining effective combat capabilities.

• US Armed Forces must be able to operate and train with systems in the US the same way these

systems would be employed in the full range of missions worldwide.

• The loss of operational capability is directly linked to the potential for failure on the battlefield.

• Whatever mitigation techniques are implemented, they cannot restrict DoD systems from

meeting mission requirements, i.e., DoD systems must maintain the flexibility to support current

operations.

• Warfighting capabilities provided by systems addressed in this report (e.g., SATOPS, PGMs,

etc.) are essential elements of the combatant commanders’ ability to complete their missions.
DoD IMT-2000 Assessment

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5.4 COST ASSUMPTIONS

• Cost estimates for all systems and scenarios are preliminary and representative, not conclusive.

The costs reflect estimated funding for the candidate relocation bands and time frames assumed

for relocation.

• All costs are presented in Then Year dollars (TY$).

• The methodology for cost estimates follows generally accepted cost estimation practices of the

DoD and is generally consistent with the cost methodology set forth in the January 17, 2001

NTIA cost reimbursement NPRM.

• Costs are sensitive to band selection and will require revisiting upon actual band determination.

• Additional manpower, where required, was included in some cost figures.

• For satellite control systems, it was assumed that no matter to what extent the 3G systems are

built out, the SGLS link will remain viable. Therefore, the costs shown assume that no DoD

satellites nor supporting infrastructure will require accelerated or premature replacement due to a

lost TT&C link. If the SATOPS link becomes unusable at some point and, therefore, some DoD

satellites will need replacing and ground infrastructure will need modifications, the costs will

increase significantly relative to those presented here.

5.5 SCHEDULE ASSUMPTIONS

• Dates identified for DoD accommodation of IMT-2000 are predicated on funding for

programmatic actions being available in FY02.

5.6 IMT-2000 ASSUMPTIONS

• The technical parameters describing IMT-2000 equipment used in this report are a reasonable

representation of several candidate IMT-2000 systems that may be deployed in US markets.

• The spectrum requirements defined in ITU-R Report M.2023 reflect a reasonable estimate of the

deployment of IMT-2000 systems at full build-out.

• IMT-2000 networks will mature over the course of several years with urban areas maturing first.

• On occasion IMT-2000 base station and mobile receivers may operate near minimally acceptable

performance levels.
DoD IMT-2000 Assessment

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5.7 SATOPS ASSUMPTIONS

• SATOPS minimum antenna elevation angles may fall between 3 and 5 degrees above the

horizon.

• SATOPS uplink transmitter powers may range from 100 watts to 10 kW.

• Existing emission spectra and frequency plan of current SATOPS uplinks are as defined in the

SATOPS system description.

• SATOPS earth station antennas must support 360° azimuthal coverage.

• All spacecraft launched after 2010 will be Unified S-band (USB) capable.

• A space-qualified SGLS/USB capable commercial-off-the-shelf (COTS) transponder that meets

DoD communication security (COMSEC) and other requirements will not be available for

integration before July 2004. A transponder with program specific capabilities will not be

available until 2005. This assumes the decision to proceed with the transponder program will be

by July 2001.

5.8 TACTICAL RADIO RELAY ASSUMPTIONS

• Transmitter and receiver sites may occur anywhere within selected training ranges.

• National Guard and Reserve units will regularly train with radio relay systems at appropriate

sites throughout the country.

• Tactical radio relay systems may occasionally operate near minimally acceptable performance

levels.

• The AN/GRC-245 radio would be available in sufficient quantities to replace the AN/GRC-226

radio and the AN/GRC-103 radio before 2010.

• A new radio could be developed to support the DWTS function at frequencies above 2 GHz.

However, the antenna beamwidths at higher frequencies would be much narrower than those

provided by the current band. Operational needs would require the development of new antenna

technology to support these mobile command and control links.

5.9 ACTS ASSUMPTIONS

• Areas around two training ranges, Cherry Point Marine Corps Air Station (MCAS) in the eastern

US and Nellis Air Force Base (AFB) in the western US, may be considered typical locations for

determining IMT-2000 aggregate environments to ACTS airborne receivers.

• For determining desired signal levels at airborne receivers, 35 km and 78 km separations from

the ground transmitters are typical and near-maximum values, respectively, for the
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TACTS/ACMI. For the JTCTS, air-to-air transmitter-to-receiver separations of 78 km and 278

km are typical and near-maximum values, respectively.

• The 9000 m altitude used for the analysis is a typical aircraft altitude used for flight training,

although some altitudes as great as 20,000 m may be necessary.

• ACTS ground station antenna heights of 30 m are typical or near-maximum values.

• Specified maximum communications ranges and other capabilities of the ACTS are to remain

unchanged, as system components are redesigned to operate in frequency bands different from

those presently used.

5.10 TACTICAL CONTROL LINKS/PGM ASSUMPTIONS

• Operation without interference at the pod-to-terminal separation distance analyzed in the

classified appendix (Appendix F) is a requirement.

• Pod and terminal altitudes can be between ground and 30,000 ft above ground level.

5.11 OTHER SYSTEM ASSUMPTIONS

• Army Corps of Engineers Fixed Point-to-Point communications antenna towers are typically no

more than 80 m in height.

• Permanent frequency assignments recorded for Army Corps of Engineers Fixed Point-to-Point

communications operations are indicative of actual use (i.e., that 1755 to 1850 MHz and 1710 to

1755 MHz microwave links have not been replaced with other communications media as yet).

• Locations where the Land Warrior LAN and CIDDS will operate lie within all DoD test,

training, and operational areas within the US.

• Size, weight, and power will have to be minimized because of the small size of the UAV.

• The communications link budget must be maintained without added complexity.

• The Pointer and Exdrone altitudes may vary from 0 m to 3280 m above ground level.
DoD IMT-2000 Assessment

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6.0 SUMMARY OF RESULTS

6.1 RESULTS FOR CONSIDERED OPTIONS

The accommodation of IMT-2000 services into the 1755-1850 MHz band will have unacceptable

impacts to the current DoD systems operating in the band, even if accommodation were deferred until

2010 or beyond. The impacts are unacceptable with regard to the ability of the US military forces that

use DoD RF systems to achieve and maintain warfighting readiness. In addition, millions of civil and

international users of GPS timing and navigational services will be adversely impacted. Mitigation

measures would be required for both DoD systems and IMT-2000 systems for partial accommodation of

IMT-2000 services under certain sharing or segmentation options. These measures would have major

cost and functional impacts to the DoD and may prove unacceptable as a business case to IMT-2000

service providers. The potential for DoD to transition completely out of the band is not possible for all

non-space systems until at least 2010 or later, and for space systems, it is not possible until at least 2017

or beyond. However, the government must maintain assured access to the 1755-1850 MHz band until

all legacy systems operating in this band have completed their missions. These missions are expected to

last until the 2020-2030 timeframe. Therefore, vacating the band is not possible for the DoD according

to IMT-2000 timelines. The cost presented in Table 6-1 for total band loss (Option 4) is according to

DoD timelines (2020-2030). Transition out of the band would require cost reimbursement and provision

of sufficient bands of comparable spectrum below 3 GHz. Such replacement spectrum must provide

primary status and equivalent regulatory protection.

With respect to cost issues, Table 6-1 summarizes preliminary reimbursement cost estimates for the

options addressed in this study. Since DoD cannot modify any systems by 2003, and since operational

restrictions are considered unacceptable, accommodation of IMT-2000 in this band in that timeframe is

not considered feasible, thus no costs are presented. Under any 2003 scenario, the burden of mitigation

would need to be borne completely by IMT-2000 systems. For the 2006 timeframe modification of

DoD systems could be underway to accommodate band segmentation. However, any migration of DoD

systems will not be feasible until at least 2010 or beyond, thus costs are only shown for the 2010

timeframe. Under no schedule is full band sharing considered feasible, thus no costs are shown for that

option. All costs presented are extremely sensitive to the critical assumptions outlined in Section 5.

Although the costs of all affected systems are included, the differences between the band segmentation

options are preliminary in the affected satellites and their associated ground stations. The portion of the

band lost will determine which satellite systems will be unable to utilize SGLS in the future. The

biggest single satellite system that is affected by options 2B/3B, but not by options 2A/3A, is GPS.
DoD IMT-2000 Assessment

6-2

Because GPS uses the 1755-1850 MHz for its mission data uploads as well as TT&C, the loss of

government use of the GPS uplink channel is a major cost driver.

There are many key underlying assumptions for the costs provided in Table 6-1. From a costing

perspective, the most important observation is that the numbers in the table represent only one point on a

graph of expected cost versus risk. All of the cost figures are very sensitive to many complex technical

and budgetary unknowns. Time did not allow for the quantification of these risks and the resulting

simulation that would have established the range of cost and the probability of realizing a cost within the

range. Based, however, on apparent risk, it would be consistent to expect a significant range of probable

cost. Changes in any of the variables, including the development of the IMT-2000 systems themselves,

could cause significant changes in the results provided herein. Perhaps the most important assumption is

that the DoD will maintain access to this band to satisfy mission objectives until the last 1755-1850

MHz satellite is no longer functioning. This assumption is key because if this was not the case, many

DoD satellites would require replacement, increasing the overall cost many-fold. This would be

operationally unacceptable because it is unclear when replacement satellites could be developed, built,

and launched to maintain DoD satellite system capabilities or if industry even has the capacity to

provide these replacement satellites in a timely manner. Another extremely critical assumption

underlying the cost figures is that comparable alternate bands are made available for the systems that

require relocation, e.g., the weapon links and the tactical radios. If comparable alternate bands are not

identified, the DoD would lose the capability provided by these critical systems, which is unacceptable.

Finally, secondary and tertiary impacts have not been included in the costs presented. An example of

these costs includes increased comparable band coordination costs.

Table 6-1. DoD Cost and Schedule Summary (TY$B)

Full Band Sharing

(Option 1)

Band Segmentation

Lose 1805-1850 MHz

(Option 2A/3A)

Notes 1,2,3,4

Band Segmentaion

Lose 1755-1790 MHz

(Option 2B/3B)

Notes 1,2,3,4

Total Band Loss

(Option 4)

Notes 1,2,3,4

Not Applicable $2.8 $3.9 $4.3

1 Requires provision of certified comparable spectrum (NDAA 00)

2 Requires cost reimbursement (NDAA 99)

3 Requires protected spectrum access to the band through any transition

4 Complete DoD migration is not possible until beyond 2010 for non-space systems and beyond

2017 for space systems

In summary, since the band sharing option introduces significant operational risks, no costs are

presented. The cost to reimburse DoD for the band segmentation options, given the assumptions and

mitigation strategies discussed in detail below, is either $2.8B or $3.9B, depending on which option is

chosen. If the entire band is lost, the cost would be at least $4.3B; however, total migration of DoD
DoD IMT-2000 Assessment

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systems from this band is not possible within any of the dates established by the Presidential study plan

and in fact could not be completed until well after 2020.

6.1.1 Full Band Sharing

Full band sharing between DoD and IMT-2000 systems is not feasible due to prohibitive separation

distances. The successful simultaneous operation of DoD and IMT-2000 systems in a number of

populated regions will be prevented by the interference interactions expected between DoD systems and

IMT-2000 systems. It is not known whether the potential impact or possible mitigation restrictions on

IMT-2000 systems are acceptable to industry, however those that may be imposed on DoD systems

would have unacceptable impacts. These include major limitations on airborne operations involving

aircrew training and weapons testing such that military mission requirements could not be met. Tactical

communication systems would be limited in operation to only remote areas and even then would require

significant coordination efforts. The ground network used for the primary control of critical DoD

satellites could be required to limit operational parameters (satellite contact frequency and duration,

contact time of day, transmitter power, etc.), which would put the health of all constellations at risk.

On-orbit spacecraft would be susceptible to interference from aggregate IMT-2000 system emissions to

the point that effective spacecraft control could be lost.

6.1.2 Band Segmentation/Partial Band Sharing

Band segmentation options consistent with those presented in the study plan were assessed. The first

segmentation option (Option 2A) evaluated is the accommodation of IMT-2000 systems into the 1805-

1850 MHz segment of the band while the government systems maintains its operation in the remaining

1755-1805 MHz portion of the band. This segmentation option with the addition of comparable

spectrum (Option 3A) for DoD operations was also considered. Another segmentation option that

allowed for a phased entry of IMT-2000 systems was addressed. In this segmentation scenario (Option

2B), government operations would be retained in 1790-1850 MHz while the 1755-1790 would

potentially be reallocated to non-government use as part of a phased introduction. The phasing

considered allowed IMT-2000 systems to be introduced into the 1710-1755 MHz portion of the band

immediately followed by additional access to 1755-1780 MHz at a mid-term future date, and 1780-1790

MHz would be made available in the long term. The final segmentation option (Option 3B) used the

same phased availability of spectrum for non-government use and also made additional comparable

spectrum available for DoD use.
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Options for DoD to vacate certain portions of the 1755-1850 MHz band to IMT-2000 operations will

also result in significant impacts to DoD system operations. Accommodation as a result of any

segmentation option would take many years and would require cost reimbursement. Absent provision of

comparable spectrum (and to date no such comparable spectrum has been identified), all of the DoD

major systems in the band would experience serious operating restrictions due to the loss of spectrum

access under either of the segmentation options. In order to support adequate mission capabilities, DoD

requires access to additional spectrum in the mid 2 GHz area and below on a primary basis with

equivalent regulatory protection to 1755-1850 MHz, in order to support large military exercises, aircraft

and missile testing, and fighter aircraft combat proficiency training. In addition, specific system

acquisition programs would require changes and additional funding to enable DoD systems to ensure

operating effectiveness under either segmentation option. These changes include program accelerations,

design modifications, and fielding of upgraded systems to installations or units that currently do not plan

to field the upgraded capability. While either segmentation option would have impacts to all major DoD

systems, the option that would take a phased approach with initial IMT-2000 services in the 1710-1755

MHz portion of the band would reduce the impacts to most systems for a number of years. This would

allow time for programs to receive funding through reimbursement to make equipment/band transitions

and implement mitigation measures. Elimination of OBRA-93 conditions, i.e., the continued existence

of protected federal government sites at a number of locations throughout the US at which DoD

operations can continue with the same level of regulatory protection as at present, would result in an

immediate impact to PGMs and other systems.

Due to the potential for degradation to operational capability, losing access to any significant portion of

the 1755-1850 MHz band without access to additional comparable spectrum and adequate time to

withdraw from the specified band is unacceptable to the DoD. If the conditions of full cost

reimbursement, on time program execution, and operationally protected use of the spectrum through the

course of any necessary transition are met, some band segmentation may be feasible. The feasibility of

any segmentation requires the full cooperation of the IMT-2000 industry. This cooperation entails

acceptance of DoD transition timelines and DoD’s continued unrestricted operation in the existing band

during the course of any transition. The timelines for accommodation of IMT-2000 in any significant

segment of the 1755-1850 MHz band by the DoD are comparable to those of full band sharing. Given

that the above conditions are met, transition by the DoD for this option could not be completed until

2010 or later for the most non-space systems and until 2017 and beyond for the space systems. As in the

case of vacating the total band, migration prior to these dates would require premature system

termination, which would have extremely serious implications to the DoD’s ability to effectively

execute its mission. These dates are also predicated on funding availability in FY02.
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6.1.3 Vacating the Band

DoD vacating the 1755-1850 MHz band in the near-term would cause serious national security impacts.

No amount of funding could mitigate the impacts in the near-term. Terrestrial systems would require at

least 10 years (no earlier than 2010) to completely transition out of this band and into a band of

comparable characteristics. To date, no bands or combination of bands surveyed by DoD or proposed

by NTIA have proven suitable for a relocation of DoD systems currently resident in 1755-1850 MHz.

Space systems are not expected to completely transition out of the band until after 2020-2030.

6.2 RESULTS FOR INDIVIDUAL SYSTEMS

6.2.1 Satellite Operations

The ability to support pre-launch, launch and early orbit activities, on-orbit operations, anomaly

resolution, and end-of-life management is absolutely critical to satellite control and management.

Impact to SATOPS functions is manifested in one of two areas: impact to the spacecraft receiver from

IMT-2000 terrestrial emission, and restrictions placed upon the DoD’s terrestrial uplink operations to

accommodate IMT-2000 operations. Unlike terrestrial-based systems, space-based hardware cannot

undergo a frequency change once the hardware is launched. Since all of the DoD satellites rely on

SGLS control afforded by the Air Force Satellite Control Network (AFSCN), Naval Satellite Operations

Center (NAVSOC), GPS, and DSP networks, continued protected access to the spectrum used by these

on-orbit assets is required to maintain control of the satellites and associated mission payloads.

Given that SATOPS functions are performed across the 1755-1850 MHz frequency band, band

segmentation or band vacating schemes have unacceptable impacts to existing satellites utilizing the

affected portions of the spectrum unless continued protected access is maintained through the course of

any transition. Even with assured access, unacceptable impacts to satellite uplink closure reliability are

expected starting in 2006 under typical uplink operating parameters. Under certain conditions, increased

uplink power may not provide adequate link margin.

Denying SATOPS the spectrum needed to support on-orbit assets will result in a partial or complete loss

of TT&C capability. This will result in varying degrees of impact to the spacecraft including orbitpositioning errors, loss of payload control leading to eventual malfunctions and mission failure, and

ultimately, complete loss of the satellite. Mission capabilities such as missile warning, navigation,

military communications, weather, and intelligence, surveillance and reconnaissance would be severely

impacted until such time that a replacement capability could be launched. Failure to support GPS and
DoD IMT-2000 Assessment

6-6

weather services satellites not only impacts military operations but also will have adverse consequences

for the civilian community.

For all three options, band segmentation, band sharing and vacating the band, the DoD must retain full

SATOPS operational capability and regulatory protection to support existing satellite systems until their

end-of-life. Mitigation techniques exclusive to the IMT-2000 community such as the establishment of

coordination zones (areas surrounding SATOPS uplink sites) allow access to the spectrum without

operational impact to the DoD. Other techniques such as IMT-2000 dynamic frequency reallocation

may have some operational and cost impacts depending upon the specific implementation.

6.2.2 Tactical Radio Relay

6.2.2.1 Mobile Subscriber Equipment and TRI-TAC

For the band sharing option in the 2003 time frame, the Army must continue to operate MSE and TRITAC in the 1755-1850 MHz band for realistic battlefield training. Because there are no material

solutions available in this time frame to facilitate sharing, it is anticipated that restrictions on military

systems would result, thereby impacting operations as they are conducted today. Restricting

transmitter/receiver locations and antenna pointing directions will limit realistic training of units and

limits the commanders’ ability to realistically deploy signal assets. Restricting training deployments to

pre-planned, pre-coordinated sites exercise-after-exercise reduces the microwave operator’s combat

skills. The learning curve for establishing tactical links in actual deployment situations will be steeper

and longer because of the lack of realistic field exercise training. The time required to establish

effective command and control, especially in the information intensive battleground today, may be a

deciding combat factor.

Army Guard and Reserve component units located primarily in urban/suburban areas with ACUS/MSE

and TRI-TAC systems may be severely restricted in training opportunities because of their proximity to

IMT-2000 base stations/mobile phone concentrations. If these units are restricted from training

operations at home locations, then the units must deploy to the nearest training area thereby imposing

increased costs on training that are accomplished today with relatively small investment.

If 3G systems were accommodated in this frequency band, the Army installation Frequency Managers

would need to coordinate with IMT-2000 system’s operators prior to conducting training exercises. The

frequency managers at most of the Army’s training ranges are already facing crowded frequency space

and further sharing restrictions will make any large-scale exercises unworkable.
DoD IMT-2000 Assessment

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For 2006 and 2010, the operational impact to US forces if IMT-2000 systems begin operation in the

1755-1850 MHz band are the same as 2003, unless access to additional spectrum in bands up to 2690

MHz is provided on an primary basis with equivalent regulatory protection. As the High Capacity Lineof-Sight (HCLOS) radios replace the current generation of MSE and TRI-TAC equipment, the

additional flexibility in frequency selection could reduce, but not eliminate, the impact resulting from

loss of the 1755-1850 MHz band provided access to an equal amount of additional spectrum and

operating frequencies between 1850 and 2690 MHz is granted.

By 2003 for the segmentation options, any reduction in available spectrum would further reduce the size

and scope of training exercises in training areas where frequency space is already at a premium.

Fielding of HCLOS radios would not be sufficient to provide any significant relief in this time frame.

Impacts to Army training would be similar to those described in the band sharing option around large

training areas; however, impact to Reserve and National Guard units will be minimal if access in the

remaining government spectrum is maintained.

For the 2006 time frame, some impact to training is expected, however, fielding of HCLOS radios will

improve the situation if access to frequencies up to the mid 2 GHz region is provided on a primary basis

with equivalent regulatory protection. By the 2010 time frame, HCLOS fielding should have replaced

current generation radios.

Vacating the entire 1755-1850 MHz band is not an acceptable option for the Army. This band is an

essential element of Army battlefield communication networks for the foreseeable future, including the

new HCLOS radio. Alternate higher frequency bands such as 4.4 – 5.0 GHz, are not suitable for tactical

communication systems like MSE. The 1700 MHz band is used for mobile communications because the

propagation characteristics allow for penetration of foliage, use of easy to handle coaxial cables instead

of expensive and fragile wave guides, and have a wide beam width allowing for quicker path alignment.

These characteristics are critical to tactical mobile communications units because of their mission to

provide the Army with the ability to relocate command centers quickly. Moving the communications

network to a higher frequency band would negate many of these factors, thus decreasing the operational

utility of the system. The operational implications from the inability to train in the US would directly

impact combat operations.
DoD IMT-2000 Assessment

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6.2.2.2 Digital Wideband Transmission System

The Navy/Marine Corps depend on the DWTS for information transfer between ships and troops ashore

as well as dissemination throughout the battlefield. There are no replacement radios planned for the

DWTS, so continued access to the 1755-1850 MHz band is crucial to amphibious operations training.

Full-band sharing between DWTS and 3G systems and segmentation options result in the same

challenges as described previously in the section on ACUS/MSE. Restrictions on DWTS operation that

would be expected under a full band-sharing scenario reduce or eliminate the utility of training in the

establishment and operation of this vital link.

Limiting the size of exercises severely restricts the utility of training activities. If the Marine Corps

could no longer stage MEF/division level exercises, it loses the ability to properly train its troops, and

also loses the capability to rehearse for deployments. This reduces the readiness of our warfighters by

increasing the time required to establish critical command and control links. Restricting training to

certain specified ranges would also severely impact operations. This requires large troop movements to

other training locations at an increase in both cost and lost time. This especially impacts the Reserve

units, as they would no longer be able to participate in training in areas where the density of IMT-2000

is high, but would have to travel to specified training locations or ranges.

These impacts would be essentially the same in both the 2003 and 2006 time frames. As stated

previously, no replacement radio is currently planned, and even if a replacement is leveraged with the

HCLOS radio, redesign would be required to meet the Marine Corps requirements for mobility and

platform suitability. Any replacement, incorporating the frequency flexibility of the HCLOS radio

would not be available in sufficient quantities before the 2010 time frame. If such a program is

executable and, if access to frequencies in bands up to the mid 2 GHz range is provided, the impact to

amphibious training may be significantly reduced. However, access to frequencies in the low end of the

DWTS range must be available to support the ship-to-shore communications requirements.

Vacating in either the 2003 or 2006 time frame would result in severe reductions in operational

readiness of troops responsible for amphibious communications. This is not considered a viable option

for the Marine Corps. Vacating the band would only be considered viable after a new specific frequency

band is identified and a new system is developed, tested and fielded.
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6-9

6.2.3 Air Combat Training Systems

Full band sharing of the 1755-1850 MHz spectrum with ACTS and 3G systems is not considered to be a

viable option. Distance separations needed to preclude interference are substantial. Coordination and

scheduling of shared spectrum between DoD training ranges and IMT-2000 is not possible due to

complex range operations and the requirement for immediate support of unplanned training exercises.

Sharing would limit or preclude large-scale joint training exercises and limit migration to rangeless airto-air operational training.

No replacement or modified ACTS could be deployed by 2003; thus, it is anticipated that under full

band sharing in this time frame, all current TACTS/ACMI would be forced to cease operation or face

such restrictions as to render their utility nearly zero. The absence of instrumentation to support live

tactical training would result in direct loss of readiness for combat forces.

Current plans call for existing ACTS to be operating well past 2010. Under the current plan, JTCTS

would not begin replacing fixed range systems until after 2006, with a replacement schedule into at least

the 2010 time frame. However, even with a conversion to JTCTS, there are no mitigation techniques

that could be implemented in either JTCTS, legacy ACTS, or IMT-2000 to allow successful cofrequency operation in the same geographic region.

For segmentation Option 2, interference between the ACTS data link and IMT-2000 equipment will

occur. The RF interference will adversely affect system operation. Interference with uplink frequencies

(1830 and 1840 MHz) will render ACTS airborne instrumentation inoperative while interference with

ACTS ground-to-ground RF links could vary with portions of the range becoming inoperative to total

system failure. Additionally, there is no current way to limit system operation to a portion of the band;

therefore, it must be assumed ACTS operation will adversely affect IMT-2000 systems. This would

likely cause severe restrictions to TACTS/ACMI emissions thus significantly reducing system utility.

If the ACTS loses access to the 1805-1850 MHz band in 2006, the impacts would be similar to those

described for 2003 unless modification to the existing frequency plan is pursued. A remanufacture of

existing ACTS hardware (updating for obsolescence and technology advances) might make operation of

the legacy systems within a reduced bandwidth feasible. It is estimated the fielding of the proposed

ACTS modifications could be accomplished for all ranges by 2006 provided these modifications begin

in FY02. For 2010, the assessment is the same as the assessment provided for 2006 except that risk is

reduced based on additional time to deploy. The operational impact can be minimized if no spectrum

conflicts arise with other incumbent systems and all the mitigation efforts are completely implemented
DoD IMT-2000 Assessment

6-10

by 2006 (schedule risk) or if turnover of the 1805-1850 MHz band is delayed at sites where mitigation

measures have not been completed by 2006. The replacement of the legacy ACTS by JTCTS is not

scheduled to begin until at least 2008. Any loss of current system use or functionality would impact the

training and readiness of the aircrews.

Under Option 3, if IMT-2000 build-out is contained below 1755 MHz until perhaps the 2006 time

frame, there would be little impact to ACTS operations during that time. If IMT-2000 equipment is

deployed to use frequencies above 1755 MHz, impacts to ACTS would occur. Under the current plan,

JTCTS would not begin replacing fixed range systems until after 2006, with a replacement schedule into

at least the 2010 time frame. The 2006 time frame would not allow for the replacement of legacy

TACTS even with a drastically accelerated JTCTS program. If started soon enough, a modification

program for the legacy TACTS may allow it to keep operating in the 1780-1850 MHz band. This may

allow sufficient time (i.e., until past 2010) for all legacy ACTS to be replaced by JTCTS. Once suitable

spectrum is identified, the ground-to-ground microwave links may be relocated. Operational impact is

none, if spectrum conflicts do not arise with other incumbent systems and all the mitigation efforts are

completely implemented by 2006 (schedule risk), or if turnover of the 1755-1780 MHz band can be

delayed at sites where mitigation measures have not been completed by 2006. Any loss of current

system use or functionality would impact the training and readiness of the aircrews.

For vacating the band entirely, one option presented is to upgrade all ACTS ranges and equipment with

a GPS tracking capability and replace existing RF hardware with new, state-of-the-art, digital

equipment. The 2200-2290 MHz band is congested and unlikely to accommodate ACTS operations.

This option could not be implemented by 2003. Therefore, vacating the current band in this time frame

would impose unacceptable impact to combat training. One of the above options for moving to an

alternate frequency band could possibly be implemented by 2006 with schedule risk or by 2010.

However, unless continued operation of legacy ACMI is assured in the interim, operational training for

aircrews would be severely restricted.

6.2.4 Tactical Control Links/Precision Guided Munitions

Co-frequency operation under full sharing of this frequency band with IMT-2000 systems could impose

significant restrictions on DoD operations because PGMs are not able to operate with IMT-2000 systems

on a non-interference basis. To accommodate IMT-2000, a modification to these data links must be

made to prevent IMT-2000 systems interfering with the weapon data link in target areas where IMT2000 systems are established. No replacement systems are currently planned for these PGM systems

and until one is fielded, current PGM training must continue to use this frequency band.
DoD IMT-2000 Assessment

6-11

Segmentation options are similarly unworkable. Due to the design of this system, any modification

would be as complex and costly as vacating the entire band.

If the PGM data links have to vacate the current frequency band in 2003, there would be immediate loss

of combat capability to the warfighter. The PGMs could not be used to their full potential due to

training shortfalls. These are the only systems that provide precision attack capability from a fighter

aircraft, and they represent the vast bulk of the total precision capability from all aircraft. By the end of

2007, all of the weapon control pods, support equipment and 20% of the weapon data terminal inventory

could be modified to operate with a new set of frequencies. By the end of 2011, modification of the

remaining weapon data terminals could be completed, assuming funding is available by FY02.

6.2.5 Other Systems

6.2.5.1 Corps of Engineers

Since the fixed point-to-point microwave links tend to be in remote areas, sharing should not present a

problem. For those links near population centers or IMT-2000 systems, frequency sharing could be

coordinated; otherwise, the link will have to be relocated in the spectrum. Band segmentation is

acceptable as long as the microwave system is capable of operating in that portion of the band. This

should apply to individual links, not the microwave system as a whole. Those links situated in a highdensity IMT-2000 environment may need to be relocated in the spectrum. During any relocation, the

current link must be kept operational until the new link is ready for cutover to prevent remote facilities

from being unmonitored.

6.2.5.2 Land Warrior

Any sharing or segmentation option would require the Army, in conjunction with the IMT-2000

industry, to develop acceptable frequency use coordination procedures. Although this option appears

attractive, the restrictions for sharing, such as limiting operations, locations, and link length, may inhibit

the full use of this system by the Army. The Army’s policy is to train as it fights; thus, limiting the size

and scope of the training exercises violates this mandate. Also, Army Guard and Reserve unit training

at home locations will be similarly affected. Fully vacating the band requires a system redesign and

delays fielding the system.
DoD IMT-2000 Assessment

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6.2.5.3 Combat Identification for the Dismounted Soldier

Like Land Warrior, any sharing or segmentation option would require the Army, in conjunction with the

IMT-2000 industry, to develop acceptable frequency use coordination procedures with the same

impacts. Fully vacating the band requires a system redesign and delays fielding the system. The

current operational impact is none, but delaying the fielding of the system may increase the likelihood of

continued fratricide during future conflicts.

6.2.5.4 Pointer Unmanned Aerial Vehicle

Sharing may be acceptable and possibly workable but would require the Army, in conjunction with the

IMT-2000 industry, to develop frequency use coordinating procedures. There may be restrictions for

use that will limit the effectiveness of the system. Vacating the band would require identifying a new

comparable band and equipment modification. Overall operational impact is minimal since only four

models have been made so far. However, a change will delay fielding and use by Army infantry units,

Air Force security forces, and NASA launch facilities monitoring.

6.2.5.5 Aberdeen Test Center

Without any mitigation, interference from IMT-2000 users operating at the same frequencies would

disrupt the acquisition of data in support of the testing of military vehicles and equipment, essentially

shutting down the test range. Segmentation will require modification or replacement of the range

equipment. Additional frequencies must be made available and selected to eliminate interference with

the current frequencies. Unless additional spectrum is allocated and current regulatory protections

extended until new equipment is procured and fielded, range operations will be affected adversely.

6.2.5.6 TOSS

If mitigation from IMT-2000 is not used or the system is not replaced, TOSS would be rendered nonoperational. Without the feedback from TOSS, range scoring would revert to manual methods. This

inability to produce near-instantaneous feedback negatively affects the quality of crew training.

Training missions involving multiple bombing runs would not have the benefit of feedback from

previous ordnance drops to correct any deficiencies before the next drop. Aircrew proficiency in

weapons delivery will be reduced.
DoD IMT-2000 Assessment

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6.3 ALTERNATE BANDS

Alternate bands identified in the study plan (2025-2110 MHz, 2200-2290 MHz, 4.4-5.0 GHz and 7-8

GHz) were evaluated to investigate the potential for housing DoD systems that may be displaced

through accommodation of IMT-2000. Review indicates these bands could not accommodate the

introduction of the additional non-space systems without operational degradation to and from critical

systems such as the Cooperative Engagement Capability, the Defense Satellite Communication System,

DoD satellite downlinks, and numerous fixed and mobile operations. The 2025-2110 MHz band may be

feasible for the introduction of the DoD satellite operations functions but there are specific regulatory

issues that must be addressed. Although other bands were not evaluated in this report, the availability of

sufficient comparable spectrum is unlikely in light of the ever-growing demand and competition for

spectrum access. Finally, availability of comparable spectrum must be certified in accordance with

NDAA 2000 prior to any reallocation decision involving some or all of the 1755-1850 MHz band.

In assessing the feasibility of sharing or segmentation of the designated band, or migration out of the

band, this report addressed only existing and planned DoD systems. Given the growing demand for

spectrum to support information-intensive operations, it is highly likely that new DoD requirements for

this band and other DoD bands will arise. Thus the full impact to DoD of surrendering all or a portion

of the band may be greater than the assessment provided in this report.
DoD IMT-2000 Assessment

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6.3 ALTERNATE BANDS

Alternate bands identified in the study plan (2025-2110 MHz, 2200-2290 MHz, 4.4-5.0 GHz and 7-8

GHz) were evaluated to investigate the potential for housing DoD systems that may be displaced

through accommodation of IMT-2000. Review indicates these bands could not accommodate the

introduction of the additional non-space systems without operational degradation to and from critical

systems such as the Cooperative Engagement Capability, the Defense Satellite Communication System,

DoD satellite downlinks, and numerous fixed and mobile operations. The 2025-2110 MHz band may be

feasible for the introduction of the DoD satellite operations functions but there are specific regulatory

issues that must be addressed. Although other bands were not evaluated in this report, the availability of

sufficient comparable spectrum is unlikely in light of the ever-growing demand and competition for

spectrum access. Finally, availability of comparable spectrum must be certified in accordance with

NDAA 2000 prior to any reallocation decision involving some or all of the 1755-1850 MHz band.

In assessing the feasibility of sharing or segmentation of the designated band, or migration out of the

band, this report addressed only existing and planned DoD systems. Given the growing demand for

spectrum to support information-intensive operations, it is highly likely that new DoD requirements for

this band and other DoD bands will arise. Thus the full impact to DoD of surrendering all or a portion

of the band may be greater than the assessment provided in this report.
DoD IMT-2000 Assessment

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APPENDIX A – IMT-2000 SYSTEM DESCRIPTION

The greater portion of the International Mobile Telecommunications for the Year 2000 (IMT-2000)

system description presented below has been provided by the Federal Communications Commission

(FCC). The last part of the system description presents specific technical parameters for selected

mobile wireless technologies. These technologies were selected primarily because more technical

data was available to describe these systems. The selection of these technologies for use in this

assessment does not represent an endorsement or advocacy of those systems. Some of the IMT-2000

parameters used in the assessments were calculated using communications theory and represent

notional parameters rather than the characteristics of existing hardware. The parameters contained in

this appendix were used in the assessment to help establish the scope of sharing issues. Calculated

distances, signal levels, and margins are principally intended to assist in further analyses and to help

initiate dialogue between government and industry interest groups.

IMT-2000 and third-generation (3G) services are the names commonly used to refer to the nextgeneration mobile wireless telecommunications services. The 3G family of services, and the systems

that will provide them, are intended to reflect a high degree of commonality and are to be compatible

with each other. These services will support mobile and fixed users employing a wide range of

devices including small pocket terminals, handheld telephones, laptop computers, and fixed-receiver

equipment. Some International Telecommunication Union (ITU) Member States and Sector

Members envision 3G services to be ubiquitous throughout the globe, as available in a remote part of

a developing country as they are in an urban area in a highly developed country. The

radiotransmission technologies (RTTs) providing for standardized 3G air-interfaces were initially

agreed upon in November 1998 by the ITU’s Radiocommunication Sector (ITU-R) Task Group 8/1

and were adopted as Recommendation M.1

 Sector Members and Member States are actively working

in the ITU’s Telecommunication Standardization (ITU-T) Sector to develop 3G signaling and

communication protocols, network requirements needed to support expected 3G services, and service

definitions for IMT-2000 applications. Table A-1, derived from ITU-T Draft Recommendation

Q.1701,2 describes selected essential capabilities of IMT-2000 systems.

 

1

 ITU-R Recommendation M. [IMT.SPEC], ITU-R Radiocommunication Assembly, Istanbul, Turkey, May 2000.

2

 ITU-T Draft Recommendation Q.1701, Geneva.
DoD IMT-2000 Assessment

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Table A-1. IMT–2000 Services/Capabilities

Capabilities to support circuit and packet data at high bit rates:

- 144 kb/s or higher in high mobility (vehicular) traffic

- 384 kb/s or higher for pedestrian traffic

- 2 Mb/s or higher for indoor traffic

Interoperability and roaming among IMT–2000 family of systems

Common billing/user profiles:

- Sharing of usage/rate information between service providers

- Standardized call detail recording

- Standardized user profiles

Capability to determine geographic position of mobiles and report it to both

the network and the mobile terminal

Support of multimedia services/capabilities:

- Fixed and variable rate bit traffic

- Bandwidth on demand

- Asymmetric data rates in the forward and reverse links

- Multimedia mail store and forward

- Broadband access up to 2 Mb/s

A.1 IMT-2000 SYSTEM CHARACTERISTICS

During preparations for the World Radiocommunication Conference 2000 (WRC 2000), the United

States (US) committed to studying the feasibility of using the 1755-1850 MHz and 2500-2690 MHz

bands (or parts thereof) for IMT-2000 operations. It was understood that such a study would include

determining the impact of the operation of IMT-2000 systems on the systems already authorized to

operate in these bands. The 1755-1850 MHz band is used in the US to support Government services,

mostly military space operations, air combat training missions, and tactical communications

operations. The 1710-1755 MHz portion of the 1700/1800 MHz band identified at WRC 2000 is

currently in the process of becoming available for commercial use and it could be made available for

IMT–2000 services. The 1850-1885 MHz portion of the same IMT-2000 band is already used to

support personal communications services (PCS) operations in the US. The 2500-2690 MHz band is

used to provide instructional television fixed services (ITFS) and multipoint distribution services

(MDS) throughout the US.

In order to determine the impact of operating IMT-2000 systems in bands that are encumbered, it is

necessary to assess to what degree the proposed and incumbent systems can co-exist in the same

band. Stated in simplistic radio engineering terms, it is necessary to determine whether or not

harmful interference is generated into one of the systems (incumbent or proposed) by the operation of

the other(s). Furthermore, if it is determined that harmful interference is likely to occur, it is

desirable to isolate the conditions under which it occurs and whether or not means exist to mitigate its

effects and the costs associated with implementing such mitigation techniques.
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The interference assessment mentioned above requires identification of the technical characteristics

for the systems being studied and the ability to quantify the systems’ performance. These

characteristics are readily available for existing systems operating in the bands of interest. This is not

the case however for all the parameters that are required to characterize IMT-2000 systems. These

systems, many of which are in the planning or development stage, do not have well-defined or

universally accepted values associated with every system parameter. Thus it is necessary to assume

values for certain of the IMT-2000 system parameters that are to be used in the conduct of the

interference studies. When assumptions had to be made concerning values to be used in

characterizing IMT-2000 systems, an attempt was made to adopt values that are consistent with

values documented in readily available material such as the reports and recommendations of the

ITU-R, and reports or findings of industry-led working groups addressing IMT-2000 issues. Absent

any other readily available information, FCC rules for second-generation (PCS) mobile systems were

used as guides for 3G systems. In addition to values for the technical parameters themselves, it is

also necessary to assume certain characteristics of the build-out of proposed IMT-2000 services, such

as when they are likely to occur, whether there will be a time-phasing of the build-out, what regions

of the globe are likely to support build-out earlier than others, and within a region, whether there will

be a geographical preference i.e., urban versus suburban versus rural, for the build-out. These

assumptions also were based on readily available material and information where possible.

In order to perform the compatibility assessments presented in the appendices, certain specific

technical parameters needed. In these cases, communications theory and reviews of secondgeneration systems were used to help develop the needed parameters. Tables A-2 through A-5

present the final version of the technical parameters used in the calculations documented in the

appendices. It should be noted that the assessments considered only one CDMA system simply to

limit the scope of the initial assessment. Further analyses and discussions of sharing should consider

all of the IMT-2000 technologies equally.
DoD IMT-2000 Assessment

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Table A-2. Characteristics of IMT-2000 Mobile Stations

Parameter CDMA-2000 CDMA-2000 UWC-136

(TDMA)

UWC-136

(TDMA)

GPRS/EDGE

W-CDMA

Carrier Spacing 1.25 MHz 3.75 MHz 30 kHz 200 kHz 5 MHz

Transmitter Power 100 mW 100 mW 100 mW 100 mW 100mW

Antenna Gain 0 dBi 0 dBi 0 dBi 0 dBi 0 dBi

Antenna Height 1.5 m 1.5 m 1.5 m 1.5 m 1.5 m

Body Loss 0 dB 0 dB 0 dB 0 dB 0 dBi

Access

Techniques CDMA CDMA TDMA TDMA CDMA

Data Rates

Supported 144 kb/s 384 kb/s 30 kb/s44 kb/s 384 kb/s 384 kb/s

Modulation Type QPSK/BPSK QPSK/BPSK π/4-DQPSK

8-PSK

GMSK

8-PSK QPSK

Emission

Bandwidth

-3 dB 1.1 MHz 3.3 MHzf 0.026 MHz 0.18 MHz 3 GPP

-20 dB 1.4 MHz 4.2 MHz 0.034 MHz 0.22 MHz TS25.101

-60 dB 1.5 MHz 4.5 MHz 0.036 MHz 0.24 MHz

Receiver Noise

Figure 9 dB 9 dB 9 dB 9 dB 9 dB

Receiver Thermal

Noise Level

-113. dBma

-105 dBmb -109 dBma-100 dBmb -121 dBma -113 dBma -109 dBm in

384 kb/s

Receiver

Bandwidth

-3 dB 1.10 MHz 3.30 MHz 0.03 MHz 0.18 MHz N/A

-20 dB 1.6 MHz 4.7 MHz 0.04 MHz 0.25 MHz N/A

-60 dB 3.7 MHz 11 MHz 0.09 MHz 0.58 MHz N/A

Eb/No for Pe = 10-3 6.6 dB 6.6 dB 7.8 dB 8.4 dB 3.1 dB*

Receiver

Sensitivityc -107 dBm -103dBm -113 dBm -104 dBm -106 dBm

Interference

Threshold 1d -119 dBm -115 dBm -127 dBm -119 dBm N/A

Interference

Threshold 2e -104 dBm -100dBm -111dBm -103dBm N/A

a

In bandwidth equal to data rate

b

In receiver bandwidth

c

For a 10-3 raw bit error rate, theoretical Eb/No d

Desired signal at sensitivity, I/N = -6 dB for a 10 percent loss in range

e

Desired signal 10 dB above sensitivity, S/(I+N) for a 10-3 bit error rate (BER) f

Shaded values were estimated.

* Assumes Eb/No for Pe = 10-6 without diversity

N/A – Not Available

3GPP – Third-generation Partnership Project

BPSK – Binary phase shift keying

DQPSK – Differential quadrature phase shift keying

EDGE – Enhanced date rates for GSM evolution

GMSK – Gaussian minimum shift keying

GPRS – General Packet Radio Service

GSM – Global System for Mobile Communications

PSK – phase shift keying

QPSK – Quadrature phase shift keying
DoD IMT-2000 Assessment

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Table A-3. Characteristics of IMT-2000 Base Stations

Parameter CDMA-2000 CDMA-2000 UWC-136

(TDMA)

UWC-136

(TDMA)

GPRS/EDGE

W-CDMA

Operating

Bandwidth 1.25 MHz 3.75 MHz 30 kHz 200 kHz 5 MHz

Transmitter Power 10 W 10 W 10 W 10 W 10 W

Antenna Gain 17 dBi per 120

deg. sector

17 dBi per 120

deg. sector

17 dBi per 120

deg. sector

17 dBi per 120

deg. sector

17 dBi per 120

deg. sector

Antenna Height 40 m 40 m 40 m 40 m 40 m

Tilt of Antenna 2.5 degs down 2.5 degs down 2.5 degs down 2.5 degs down 2.5 degs down

Access

Techniques CDMA CDMA TDMA TDMA CDMA

Data Rates

Supported 144 kb/s 384 kb/s 30 kb/s44 kb/s 384 kb/s 384 kb/s

Modulation Type QPSK/BPSK QPSK/BPSK π/4-DQPSK

8-PSK

GMSK

8-PSK QPSK

Emission

Bandwidth

-3 dB 1.1 MHz 3.3 MHzf 0.026 MHz 0.18 MHz 3 GPP

-20 dB 1.4 MHz 4.2 MHz 0.034 MHz 0.22 MHz TS25.104

-60 dB 1.5 MHz 4.5 MHz 0.036 MHz 0.24 MHz

Receiver Noise

Figure 5 dB 5 dB 5 dB 5 dB 5 dB

Receiver Thermal

Noise Level

-117dBma

-109dBmb -113 dBma-104 dBmb -125 dBma -117 dBma -113 dBm in

384 kb/s

Receiver

Bandwidth

-3 dB 1.10 MHz 3.3 MHz 0.03 MHz 0.18 MHz N/A

-20 dB 1.67 MHz 4.7 MHz 0.04 MHz 0.25 MHz N/A

-60 dB 3.7 MHz 11 MHz 0.09 MHz 0.58 MHz N/A

Eb/No for Pe = 10-3 6.6 dB 6.6 dB 7.8 dB 8.4 dB 3.4 dB*

Receiver

Sensitivityc -111 dBm -107 dBm -117 dBm -108 dBm -110 dBm

Interference

Threshold 1d -123dBm -119dBm -131 dBm -123 dBm N/A

Interference

Threshold 2e -108 dBm -104 dBm -115 dBm -107dBm N/A

a

In bandwidth equal to data rate

b

In receiver bandwidth

c

For a 10-3 raw bit error rate, theoretical Eb/No d

Desired signal at sensitivity, I/N = -6 dB for a 10 percent loss in range

e

Desired signal 10 dB above sensitivity, S/(I+N) for a 10-3 BER f

Shaded values were estimated.

* Assumes Eb/No for Pe = 10-6 without diversity

N/A = Not Available
DoD IMT-2000 Assessment

A-6

Table A-4. IMT-2000 Traffic Model Characteristicsa

Parameter Value

Traffic Environments Rural

Vehicular

Pedestrian

In-building (Central business district)

Maximum Data Rates Rural - 9.6 kb/s

Vehicular - 144 kb/s

Pedestrian - 384 kb/s

In-building - 2 Mb/s

Cell Size Rural - 10 km radius

Vehicular - 1000 m radius

Pedestrian - 315 m radius

In-building - 40 m radius

Users per cell during busy hour Rural - not significant

Vehicular - 4700

Pedestrian - 42300

In-building - 1275

Percent of total uplink traffic >64 kb/s during

busy hour

Rural - not significant

Vehicular - 34%

Pedestrian - 30%

In-building - 28%

Percent of total downlink traffic >64 kb/s during

busy hour

Rural - not significant

Vehicular - 78%

Pedestrian - 74%

In-building - 73%

Average number of users per cell per MHz

during busy hour assuming frequency duplex

operation

Rural - not significant

Vehicular

< 64 kb/s - 16

> 64 kb/s - 4

Pedestrian

< 64 kb/s - 150

> 64 kb/s - 64

In-building

< 64 kb/s - 4

> 64 kb/s - 2 a

 Values in the table are for a mature network.

Table A-5. Rate of IMT-2000 Network Deploymenta

Calendar Year

Local

Environment 2003 2006 2010

Urban 10% 50% 90%

Suburban 5% 30% 60%

Rural 0% 5% 10% a

 For some interactions the potential for interference will be influenced by the degree to which

IMT-2000 networks are built out. This table identifies assumptions that will be used in the

assessments with respect to the degree to which US IMT-2000 networks are developed following

the granting of licenses. The levels of aggregate emissions for a fully mature IMT-2000

environment were taken from ITU-R 687.2 or other reference material as appropriate.
DoD IMT-2000 Assessment

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APPENDIX B – POTENTIAL INTERFERENCE TO AND

FROM SATELLITE OPERATIONS

B.1 OPERATIONAL MISSION OVERVIEW

B.1.1 Satellite Operations Mission Overview

The United States (US) national security depends in significant measure on vital information provided

by Department of Defense (DoD) and other critical, high priority US Government satellites. Satellite

operations (SATOPS) allow for the control of more than 120 satellites and their payloads, transmission

of mission data, and functions required to enable pre-launch, launch, and early orbit activities; on-orbit

operations; anomaly resolution (emergency operations); and end-of-life management. The DoD

performs Telemetry, Tracking, and Commanding (TT&C) SATOPS functions through ten Air Force

Space Command (AFSPC) satellite control sites and through three Navy TT&C stations within the US

and Possessions (US&P). The DoD also performs SATOPS functions outside of the US&P. This

includes the Air Force Satellite Control Network (AFSCN) common user sites and dedicated Defense

Support Program (DSP) and Global Positioning System (GPS) networks. TT&C is conducted via the

space ground link subsystem (SGLS). Satellite control functions are absolutely critical to the operations

of the spacecraft and payload. Without such control, satellites that provide for missile warning,

navigation, military communications, weather, and intelligence, surveillance, and reconnaissance (ISR)

would be jeopardized. The National Command Authority, Combatant Commanders, Services, and

national level decision-makers would be severely impacted by a reduction or loss of the capability

provided by these systems. In addition, other agencies, such as the Federal Aviation Administration

(FAA), the National Aeronautics and Space Administration (NASA), and commercial interests, would

be adversely impacted as well as Allied forces.

Because of the vital information provided to the highest levels of the US Government by SATOPS

systems, and the associated spacecraft, the potential impacts resulting from any degradation or loss of

these systems must be carefully considered. The following factors were taken into account when

evaluating potential impacts:

1. TT&C functions are critical to the control and maintenance of spacecraft. S-band offers physical

advantages for TT&C operations, particularly in the areas of launch, early orbit, and anomaly

resolution.
DoD IMT-2000 Assessment

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2. Most DoD on-orbit satellites operate on one discrete crystal-controlled frequency that cannot be

changed after launch. Only a few satellites are capable of receiving commands on more than one

frequency.

3. Satellite lifetimes often significantly exceed the design lives.

4. National and international satellite frequency registrations and coordination are completed over a

period of years. Frequency changes to satellites scheduled for near-term launch may be unable

to secure the protection that has been achieved via these regulatory actions.

5. It will be at least three years before a space-qualified crypto-enabled dual or multi-band satellite

transponder is in production.

6. It will be 4-8 years before registration and regulatory actions for any additional SATOPS uplink

frequency band are completed. There is no guarantee that all national and international

frequency coordination will be successfully completed.

B.1.2 Mission Overview of Satellites Supported by SATOPS

The following paragraphs provide a mission overview for several satellite systems supported by

SATOPS. This section is not intended to be a complete list of all satellite systems supported by

SATOPS.

B.1.2.1 Global Positioning System

The Global Positioning System (GPS) provides navigational data and precise time transfer capability to

military and civilian users all over the world. Uses of GPS include search and rescue, satellite

radionavigation for aircraft, ship and terrestrial based navigation, communications, agriculture, and

recreation. US Armed Forces utilize GPS for precision guided munitions, navigation for aerial, ground,

sea-based, and underwater platforms, unmanned aerial and sea platforms, and Combat Survivor Evader

Locator (CSEL) for Search and Rescue (SAR) operations. In addition to its navigation and timing

missions, GPS provides essential nuclear detonation (NUDET) detection data integral to the United

States Nuclear Detonation Detection System (USNDS) mission. USNDS utilizes GPS data to support

Integrated Threat Warning and Attack Assessment, Nuclear Force Management, and Treaty Monitoring

missions. The nominal GPS operational constellation consists of 24 satellites that orbit the earth once

every 12 hours. GPS relies solely upon the 1755-1850 MHz frequency band for TT&C and mission

upload capabilities.

The GPS constellation operates at Medium Earth Orbit (MEO). Currently, all Block II/IIA satellites and

five of the twenty Block IIR satellites have been launched with the last IIR satellite to be launched in

July 2006. With about 10 years average life of GPS satellites launch rates of two to four satellites per
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year are planned in order to sustain the GPS constellation. A total of 12 Block IIF satellites are being

built. The launch of the first and the last IIF satellite are scheduled to be in January 2006 and January

2010 respectively. The first of the Block III satellites, that are being defined, is planned to be launched

in January 2009.

The GPS ground segment consists of a master control station with 4-ground antennas and 6 monitor

stations. The ground antennas currently use SGLS channel 6 with uplink frequency of 1783.74 ± 2 MHz

to provide space vehicle (SV) commands, navigation message uploads, state-of-health operations and

anomaly resolution.

The ground segment also uses AFSCN remote tracking stations to support satellite early orbit

operations, anomaly resolution and as backups to the GPS ground antennas (GAs).

There is no planned retirement of the GPS constellation, but replacement satellites are scheduled for

launch well past 2010. Some of these satellites have already been built and are ready for launch. Others

are on the assembly line or in the planning stage.

B.1.2.2 Defense Satellite Communications System

The Defense Satellite Communications System (DSCS) is an integral component of the global Defense

Information and Services Network (DISN). The DSCS, consisting of earth, space, and control segments

and numerous subsystems, provides a reliable, high-capacity, quality communications capability in

support of peacetime, contingency, and wartime operations. The DSCS is a geosynchronous satellite

based system engineered and configured to provide vital command, control, and communications (C3)

service including antijam connectivity for a number of high priority circuits to the US and Allied forces

throughout the world. Specifically, the DSCS provides high availability communications services

between the National Command Authorities (NCA) and the Combatant Commands; among the

Combatant Commanders and their service component commands; between component commands and

their organic combat forces; and, among early warning and sensor sites and command centers. DSCS

relies solely upon the 1755-1850 MHz frequency band for TT&C capabilities.

B.1.2.3 Milstar

The Milstar satellite is the space element of a communications network comprised of a series of

advanced satellites linked to mobile ground terminals providing assured command and control (C2)

capabilities to US forces worldwide. The system provides undeniable connectivity, antijam
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communications and interoperability for multi-service coordination. These features are crucial to

successful operations on the modern battlefield and are not available through existing military

communications networks. New third-world threats and regional conflicts require rapid command and

control capability providing multi-service interaction, fast deployment, and timely intelligence updates.

Milstar provides the NCA and DoD users with worldwide survivable extremely high frequency

communications. The system is flexible; on-board processing can reconfigure networks to suit evolving

command and control requirements. Satellite crosslinks and onboard point-to-point routing offer direct

connectivity between the NCA and deployed forces in the field. Advanced EHF is the follow-on to

Milstar and will provide worldwide, secure, survivable satellite communications to US strategic and

tactical forces and allied nations during all levels of conflict. It will sustain the military satellite

communications architecture by providing connectivity across the spectrum of mission areas to include

land, air, and naval warfare, special operations, strategic nuclear operations and defense, theater missile

defense, space operations, and intelligence. Milstar conducts routine TT&C operations in mission bands

but relies on S-band for launch, early orbit checkout and anomaly resolution.

B.1.2.4 Defense Support Program

The geosynchronous Defense Support Program (DSP) satellites help protect the US and its allies by

detecting missile launches, space launches, and nuclear detonations. The DSP satellites use an infrared

sensor to detect heat from missile and booster plumes against the Earth’s background. Numerous

improvement projects have enabled DSP to provide accurate, reliable data in the face of evolving missile

threats. On-station sensor reliability has provided uninterrupted service well past their design lifetime.

Recent technological improvements in sensor design include above-the-horizon capability for full

hemispheric coverage and improved resolution. Increased on-board signal-processing capability

improves clutter rejection. Enhanced reliability and survivability improvements were also incorporated.

DSP relies solely upon the 1755-1850 MHz frequency band for TT&C. The Space-Based Infrared

System (SBIRS) is the follow-on to DSP, but DSP operations will continue through 2020.

B.1.2.5 Midcourse Space Experiment

The Midcourse Space Experiment (MSX) satellite and its associated ground support infrastructure

provide deep space surveillance. The MSX space-based system improves AFSPC mission of collecting

data related to deep space orbits of military and commercial satellites without the limitations inherent in

ground systems. These ground system limitations include location sensitivity, dependence on weather,

and time of day requirements. MSX has helped to increase our revisit rates on militarily significant

objects by 50 percent and has helped to reduce the list of lost satellites by 80 percent. It has enabled the
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development of standardized search techniques. MSX relies solely upon the 1755-1850 MHz frequency

band for TT&C capabilities. There is currently no planned replacement for the MSX program when it

flies out, circa 2006.

B.1.2.6 Defense Meteorological Satellite Program

The Defense Meteorological Satellite Program (DMSP) provides timely global and infrared cloud data

and other meteorological, oceanographic and solar-geophysical data vital to DoD warfighting

operations. The DMSP system consists of operational satellites in a near polar orbiting, sun

synchronous orbit at an altitude of approximately 830 km. The current DMSP constellation consists of

five spacecraft. On-board sensors record environmental data which is stored onboard and later relayed

to strategic users through the use of several worldwide ground tracking stations. Military weather

forecasters use this data to monitor and predict regional and global weather patterns, including the

presence of severe thunderstorms, hurricanes, and typhoons. This information is used by meteorologists

and plays a significant role in the planning of US military operations worldwide. DMSP also provides

worldwide, real-time weather data to small tactical terminals in the battlefield.

The DMSP satellites also measure local charged particles and electromagnetic fields to assess the impact

of the ionosphere on ballistic missile early warning radar systems and long-range communications.

Additionally, this data is used to monitor global auroral activity and to predict the effects of the space

environment on military satellite operations.

A convergence effort of military and civilian weather satellites has formed a single, converged national

environmental satellite system, National Polar-orbiting Operating Satellite System (NPOESS),

scheduled for launch in the 2007-2010 time frame. The command, control and communications for the

DMSP have been combined with the control for Department of Commerce (DoC) satellites. In June

1998, DoC took over the primary responsibility for flying both satellites.

B.1.2.7 GEOSAT Follow-On

The Geostationary Satellite (GEOSAT) Follow-On (GFO) system provides global ocean surface height,

significant wave height and wind speed measurements to Navy ship and shore (AN/SMQ-11) terminals

in real time. Data is also stored on-board and later downlinked to the Naval Oceanographic Office for

input to critical oceanographic and meteorological models. These models are used to plan naval

operations, including ship routing, and to develop undersea environmental profiles that are critical to
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submarine operations. GFO relies solely upon the 1755-1850 MHz frequency band for telemetry and

commanding functions.

B.1.2.8 Fleet Satellite Communications and Ultra High Frequency Follow-On

The Fleet Satellite Communications (FLTSAT) and Ultra High Frequency Follow-On (UFO) Satellite

Communications systems provide a variety of communications capabilities to the DoD and other

government agencies in support of a multitude of missions. These missions include supporting

communications for the NCA, Joint Chiefs of Staff, and the Unified Combatant Commands.

The FLTSAT and UFO satellites support several different types of communications systems. These

systems are Ultra High Frequency (UHF), Extremely High Frequency (EHF) and Global Broadcast

Service (GBS). A brief technical description of these systems follows.

UHF Communications Systems support mobile users using small, inexpensive, low-power terminals,

omnidirectional antennas, and operate in most weather conditions and under foliage. They typically

function in a “bent-pipe” (frequency translation) mode, but one package, the Air Force Satellite

Communications System (AFSATCOM), has a processing capability. The users of this system use

Demand Assigned Multiple Access (DAMA) standards to maximize the use of the available channels.

UHF communications on FLTSAT and UFO provide worldwide coverage (no polar coverage).

EHF Communications Systems support users requiring protected communications. EHF system

characteristics include resistance to jamming and scintillation and provide Low Probability of Intercept,

Detection, and Exploitation (LPI/LPD/LPE). These are processed systems using spread spectrum

technology. The EHF system on UFO is capable of cross-banding to the UHF system on the satellite to

support Fleet Broadcast. The EHF systems on FLTSAT and UFO provide worldwide coverage.

The GBS system supports mobile users with high bandwidth requirements for data. GBS is a broadcast

system only, providing preplanned data products to a theater in a manner similar to direct broadcast

television technology. There is a provision for receiving specific data products through the system but

requires an alternate communications path back to the data providers. The characteristics of this system

include high power transponders, small antennas for the receiver, multimedia data, and variable data

rates. This system functions as a “bent-pipe.” GBS is presently available on three UFO satellites,

providing partial worldwide coverage.
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FLTSAT/UFO relies upon the 1755-1850 MHz frequency band for primary TT&C. FLTSAT and UFO

will eventually be supplemented then replaced by the Mobile User Objective System (MUOS). First

launch of a MUOS satellite is scheduled to occur in the 2007-2008 time frame.

B.1.2.9 NATO IV/Skynet 4

The North Atlantic Treaty Organization (NATO)/Skynet Systems provide communications to the British

and NATO military forces. The NATO/Skynet networks consist of earth, space, and control segments

and numerous subsystems and provide a reliable, high-capacity, quality communications capability in

support of peacetime, contingency, and wartime operations. The US satellite command and control

support is provided under international agreements. For US provided support, NATO/Skynet relies

solely upon the 1755-1850 MHz frequency band for TT&C capabilities.

B.1.2.10 SMC/TE

The Air Force Space and Missile Systems Center Test and Evaluation (SMC/TE) directorate operates a

series of research and development satellites and ground capabilities to test/demonstrate new technology

and operational concepts. SMC/TE relies on SGLS for launch, on orbit control, and mission data for

these satellites.

Several research and development (R&D) satellites using the SGLS uplink band (i.e., ARGOS and

TSX-5) are currently in orbit but should reach end-of-life before 2003. However, additional R&D

satellites are currently planned for launch in the 2003-2004 time frame. These include CORIOLIS,

Cloudsat, and Communications/ Navigation Outage Forecast System (C/NOFS). The CORIOLIS

mission, performing risk reduction for the NPOESS program, is scheduled to launch in mid-2002 with a

minimum lifetime of three years. Cloudsat is a multi-year interagency mission, led by NASA, with DoD

support that will profile cloud cover from space. Also, the C/NOFS is expected to launch in late 2003

with a minimum lifetime of three years. Both CORIOLIS and C/NOFS, which use the SGLS band, are

expected to have operational utility to the warfighter following completion of their R&D objectives but

should reach end-of-life before 2010.

B.1.2.11 Advanced EHF

The Advanced Extremely High Frequency (Advanced EHF) is the follow-on to Milstar and will provide

worldwide, secure, survivable satellite communication to US strategic and tactical forces and

International Partners during all levels of conflict. It will sustain the Military Satellite Communications
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architecture by providing connectivity across the spectrum of mission areas to include, land, air, and

naval warfare; special operation; strategic nuclear operations; strategic defense; theater missile defense;

and space operations and intelligence.

B.1.2.12 Wideband Gapfiller

The DSCS satellites provide responsive Super High Frequency (SHF) Wideband and Antijam

communication supporting high data rate, long haul and strategic and tactical service worldwide. The

objectives of the Wideband Gapfiller Satellite Program are to provide DoD wideband data services

focused on tactical users and to augment existing DSCS and GBS (Global Broadcast System consisting

of payloads on 3 UFO satellites) constellations.

B.2 SYSTEM DESCRIPTION

The DoD conducts SATOPS functions in the 1755-1850 MHz (uplink) and 2200-2290 MHz (downlink)

bands to launch, checkout, and operate over 120 satellites flying in both geostationary and nongeostationary orbits. The Air Force, Navy, and Army, conduct satellite operations from several control

nodes within the US&P and overseas. These control nodes communicate with satellites using a

combination of global antenna networks. The DoD SATOPS uplink functions, which include the

transmission of commanding and ranging signals, are performed in the 1755-1850 MHz band. Downlink

telemetry data is passed via the 2200-2290 MHz band. The Air Force Satellite Control Network

(AFSCN) and the Naval Satellite Operations Center (NAVSOC) serve as the primary DoD common-user

satellite control networks. The AFSCN performs the bulk of the satellite operations through a worldwide

network of US Air Force ground stations and control centers which provide telemetry, tracking, and

commanding (TT&C) services to DoD and other satellites. The AFSCN consists of two control nodes,

Schriever AFB, CO, and Onizuka Air Station (OAS) at Sunnyvale, CA, plus eight Automated Remote

Tracking Stations (ARTS) dispersed both within and outside the US. In addition, the US Air Force has

mobile (transportable) satellite ground stations that deploy worldwide and perform satellite control

functions.

The GPS dedicated ground control network consists of Ground Antennas (GA) and Monitor Stations

(MS) which are used to command, receive telemetry, monitor the navigation signals and provide

navigation mission data uploads to the satellite constellation. The MS passively track the GPS satellite

navigation signals. Signals collected by the MS are processed at the Master Control Station (MCS).

The MCS uploads the GPS satellites with corrected navigation information via the GPS-dedicated GA

and one modified AFSCN remote training station (RTS) using the SGLS band. In addition to
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performing the navigation mission data upload function, the GPS dedicated GAs are also the principal

facilities used to conduct the GPS TT&C function. GPS does use the AFSCN for LEO&A operations,

the same as most other DoD satellite systems.

NAVSOC remote TT&C facilities include Laguna Peak near Point Mugu; CA, Detachment ALFA at

Prospect Harbor, Maine; and Detachment CHARLIE at Finegayan, Guam. The Navy also conducts

TT&C operations from Blossom Point, MD, and Quantico, VA.

Figure B-1 depicts the locations of the fixed US&P DoD Satellite control stations. Table B-1 lists the

DoD US&P Fixed satellite control nodes. Table B-2 lists the DoD US&P tracking and control antennas.

Table B-1. US&P DoD Fixed Satellite Control Nodes

Agency/Program Location

Air Force Satellite Control Network Schriever Air Force Base (AFB), CO

Onizuka Air Force Station (AFS), CA

Defense Support Program Buckley Air National Force Base (AFB), CO

Research, Development, Test and Evaluation Spacecraft Kirtland AFB, NM

Navy Satellite Operations Centers Naval Research Laboratory Blossom Point Field Site, MD

Naval Satellite Operations Center at Pt. Mugu Naval Air Station, CA

Naval Satellite Operations Center, Detachment Delta, Schriever AFB, CO

Global Positioning System (GPS

Master Control Station (MCS)

Schriever AFB, CO

Vandenberg AFB, CA

Table B-2. US&P DoD Command, Control and Tracking Antennas

Agency/Program Location

Air Force Satellite Control Network - Guam Tracking Station (GTS) – Andersen AFB, Guam

- Colorado Tracking Station (CTS) – Schriever AFB, CO

- Vandenberg Tracking Station (VTS) - Vandenberg AFB, CA

- Hawaii Tracking Station (HTS) – Kaena Pt., Oahu, HI

- New Hampshire Tracking Station (NHS) - New Boston Air Force Station (AFS)

- Transportable antennas

- Vehicle Checkout Facility – Cape Canaveral, FL

- Camp Parks Communications Annex – Pleasanton, CA

Global Positioning System - Ground Antenna – Cape Canaveral, FL

- Ground Antenna – Kwajalein Island

Milstar (Milsatcom) - Contractor Facility – Sunnyvale, CA

Defense Support Program - Buckley AFB, CO

Navy Satellite Control Network - Laguna Peak, CA

- Prospect Harbor, ME

- Finegayan, Guam

- Blossom Point, MD
DoD IMT-2000 Assessment

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Figure B-1. Locations of the US&P DoD SATOPS Ground Stations

Table B-3 lists the 20 center frequencies for the standard AFSCN uplink frequency plan. It should be

noted that most SATOPS uplinks conform to the 20-channel plan; however, select missions tune to

channels in-between those reflected in the standard plan.

Table B-3. AFSCN SATOPS Uplink Frequency Plan

S-band

Channel

Uplink Frequency Transmission

(MHz)

S-band

Channel

Uplink Frequency Transmission

(MHz)

1 1763.720703 11 1803.759766

2 1767.724609 12 1807.763672

3 1771.728515 13 1811.767578

4 1775.732422 14 1815.771484

5 1779.736328 15 1819.775391

6 1783.740234 16 1823.779297

7 1787.744141 17 1827.783203

8 1791.748047 18 1831.787109

9 1795.751953 19 1835.791016

10 1799.755859 20 1839.794922
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B.3 COST ISSUES

B.3.1 Satellites

DoD recently established the long-term goal of transitioning (no earlier than 2020 to 2025) the uplink

frequency band for Launch, Early Orbit and Anomaly resolution (LEO&A) from 1761-1842 MHz to

2025-2110 MHz. In support of this goal, the DoD has included the requirement in two current and

planned DoD satellite contracts for the satellites to carry a USB transponder. The costs to do this were

not included in the cost estimates provided in this report. A final decision on the transition will be made

after more detailed study and a determination if this band could provide the assured access required for

DoD satellite operations.

GPS satellites use 1761-1842 MHz to both perform LEO&A and to upload their mission data. For the

purposes of this report, GPS III, the next generation GPS space and controls segment will include a USB

capability for LEO&A operations and a 5000-5030 MHz (5 GHz) capability to support upload of

navigation mission data and “in band” commanding. All the costs both to the space vehicles and to the

GPS ground stations to relocate to 5 GHz are attributable to IMT-2000 and are included here. The delta

cost to change from SGLS to USB for the GPS III satellite is negligible and no costs for this are

included in the report. No modifications to the Block II/IIA/IIR/IIF satellites with respect to TT&C

capabilities are planned, so costs are not included for these. Those satellites will use SGLS until they fly

out.

Any migration of DoD systems will not be feasible until at least 2010 or beyond. Hence, Table B-4

makes no cost distinction by introduction date. The costs of the segmentation and options differ by

which SGLS channels are lost to DoD and which are maintained. Of course, total loss of the band is not

possible for space systems until at least 2017 or beyond. Depending on the timing of the decision

concerning the introduction of IMT-2000 into this frequency band, costs for the Wideband Gapfiller and

Advanced EHF systems could vary greatly. The costs presented in Table B-4 for these programs reflect

a decision date by July 2001. Should the decision go beyond that date, these two programs may incur

substantial cost increases, which are not reflected in Table B-4.
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Table B-4. Satellite Reimbursement Cost for Vacating the Band (TY$M)

FY02 FY03 FY04 FY05 FY06 FY07 To Complete Total

Milstar 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

Wideband Gapfiller Satellite (WGS) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

DSCS 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

DMSP 0.0 6.3 14.9 7.7 9.2 2.5 1.4 42.0

Advanced EHF 0.0 0.0 0.0 0.8 0.0 1.7 1.7 4.2

SBIRS High 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

SBIRS Low 6.0 8.8 5.2 1.4 0.0 0.0 0.0 21.4

GPS 0.9 0.9 2.9 23.8 7.1 16.7 118.2 170.5

MUOS 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

UFO 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

FLTSAT 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

Total 6.9 16.0 23.0 33.7 16.3 20.9 121.3 238.1

B.3.2 Satellite Command and Control Ground Stations

The DoD currently has numerous programs which operate ground stations that broadcast over SGLS.

The Air Force Satellite Control Network (AFSCN) is the primary system and supports TT&C activities

for virtually all DoD systems as well as other agencies, civil users, and Allied nations. The US Navy

Satellite Control Network controls various Navy satellites. GPS operates several of their own ground

stations because, unlike other DoD satellite programs, GPS also uses SGLS to upload their mission data.

DSP, and the follow-on program SBIRS High, have a critical early warning function and maintain their

own SGLS ground system for TT&C to ensure their operations are not interrupted.

The proposed AFSCN/IMT-2000 mitigation options (band segmentation) require the local IMT-2000

service provider to implement a dynamic frequency allocation system. This system could sense if the

local AFSCN site was emitting and, on what channel, and could then dynamically allocate its users to

the unused portion of the band. Also, AFSCN could implement channel filters on its antennas to reduce

out-of-channel emissions and finally, if necessary, could relocate the ground stations to remote sites. It

is not possible to implement all of these ground station changes prior to 2003, or even 2006, but they

could be completed by 2010. AFSCN costs for band sharing assume coordination zones and are for

channel filters only. AFSCN costs for band segmentation/vacating the band include channel filters and

ground station relocation.

The strategy of ground site relocation of some US&P sites would be a consideration with band

segmentation; however, it is not clear that it will be possible to identify sites for which all of the

necessary paperwork can be obtained by 2010. This is because it will be necessary to obtain BRAC

permission to move, obtain regulatory and/or legislative protection of SATOPS use at the new site, and
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to obtain environmental permission for site development. Cost impacts for those issues have not been

provided.

Tables B-5 and B-6 show the costs for both filtering and relocation of the ground stations, respectively.

Table B-5. Satellite Ground Segment Filtering Costs (TY$M)

FY02 FY03 FY04 FY05 FY06 FY07 To Complete Total

Ground Segment Filtering 11.3 11.5 11.8 12.0 12.2 12.5 38.9 110

Table B-6. Satellite Ground Segment Relocation Costs (TY$M)

FY02 FY03 FY04 FY05 FY06 FY07 To Complete Total

AFSCN 33.6 34.1 41.8 42.5 43.3 44.1 245.5 485.0

GPS 0.0 0.0 13.3 18.5 7.4 366.6 540.7 946.5

SBIRS High 49.3 68.6 38.8 11.4 2.5 2.5 50.7 223.8

GFO / NAVSOC 20.5 1.2 1.2 1.2 1.2 1.2 18.0 44.5

IMT-2000 Reimbursement 103.4 103.9 95.1 73.6 54.4 414.4 854.9 1,699.8

As discussed in the satellite section, GPS Block III plans to use USB for LEO&A and 5 GHz for

navigation mission data uploads and “in band” commanding. SGLS will continue to be used for all

TT&C operations and mission data uploads for the Block II/IIA/IIR/IIF satellites. Under the band

sharing option there is no known cost impact. Similarly, since GPS operates on SGLS channel 6,

options 2A and 3A (band segmentation) would allow DoD to retain channel 6 so there would be no cost

impact to GPS. However, under band segmentation option 2B or 3B or if the entire band is lost, option

4, GPS would be required to move its mission data link to the 5 GHz band, which would entail

substantial effort and cost. This move would be done in concert with the GPS III program and so would

not differ significantly depending upon the introduction date of IMT-2000.

B.4 OPTION 1 – FULL BAND SHARING

B.4.1 Operational Impact

DoD must retain primary user status for SGLS SATOPS functions throughout the band for all on-orbit

satellites until their end-of-life. Legacy satellite systems are expected to require SGLS support through

2030. Denying SATOPS the spectrum required to support on-orbit assets will result in a partial or

complete loss of TT&C capability. This applies to any of the sharing, segmentation, or band vacating

schemes. Denied spectrum access will result in varying degrees of impact to the spacecraft including
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orbit-positioning errors, loss of payload control leading to eventual malfunctions and mission failure,

and ultimately, complete loss of the satellite. Mission capabilities for missile warning, navigation,

military communications, weather, and intelligence, surveillance and reconnaissance would be severely

impacted until such time as a combined satellite and ground station system in an alternate frequency

band could be built and put into operational service. This would include impacts to military

communications at all levels of conflict, Navy communications to the fleet, and national intelligence

data, and military communications for our NATO Allies under international support agreements.

Assuming that spectrum access is assured, the operational impact to SATOPS capabilities is dependent

upon two factors:

1. the impact to satellite uplink closure reliability as a result of the IMT-2000 emissions, and

2. the restrictions placed upon ground based uplink capability as a result of the mitigation

techniques required to preclude EMI to IMT-2000 receivers.

Operational impact to TT&C uplinks from IMT-2000 emissions is expected in the time period 2006 and

beyond when IMT-2000 system build-out has exceeded 50 % of ITU estimates for full capacity. In

2003, it is not expected that IMT-2000 build-out will be sufficient to impact SATOPS uplink operations.

These results are based upon near-worst case but realistic uplink parameters. It should be noted that if

uplinks were conducted from worst-case disadvantaged (size, power, restricted viewing, etc.) terminals

using antennas smaller than 33 feet or lower transmitter powers, there is a potential for impact to link

closure reliability in 2003. The degree of operational impact will vary as a function of the degree to

which link closure is affected. It is expected that impact would occur for only a small set of systems and

operating conditions, although at critical junctures such as launch or anomaly resolution, such impact

would be critical.

In the 2006 and beyond timeframe, IMT-2000 emissions are expected to impact uplink closure

reliability at all orbit heights with the greatest affect occurring at LEO (approximately 850 km) and

medium earth orbit (MEO), approximately 20,000 km, orbit heights. Systems most impacted by this

include GPS, DMSP, and certain ISR systems. Should link closure be degraded to the point where

commanding cannot be performed, the impacts enumerated previous for denied spectrum access would

occur. Note that there is no expected impact to MSX satellite in 2006 given that the satellite will have

reached end of its predicted life.

Operational impacts on the SATOPS ground assets are generally limited to issues associated with the

IMT-2000 RFI mitigation techniques. The primary mitigation technique exclusive to the IMT-2000
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community is the establishment of coordination zones, areas surrounding SATOPS uplink sites within

which IMT-2000 operations may be affected. The location and approximate size of these areas are

illustrated in the technical assessment section of the report. Assuming SATOPS functions continue

unencumbered at all current uplink locations, and that IMT-2000 systems accept the potential limitations

within these coordination zones, no operational impact to DoD SATOPS ground assets is anticipated

Other IMT-2000 RFI mitigation techniques such antenna elevation angle restrictions and SATOPS

uplink power restrictions offer limited benefit and in general prove operationally unacceptable due to

impacts to satellite contact time and link margin.

Dynamic frequency reallocation, a technique where the IMT-2000 systems change frequencies in real

time to take advantage of the SATOPS changing frequency requirements, may have varying impact on

DoD ground-based SATOPS operations depending upon the specific implementation schemes.

Techniques to implement this RFI mitigation scheme need to be explored in detail with the IMT-2000

community, however the impact to DoD operations may prove to be manageable.

In 2006 and beyond, the DoD will be continuing to work toward satellite control site upgrades; however,

it will be necessary to continue operating on SGLS frequencies until all on-orbit satellites requiring

SGLS commanding have reached their end of life.

By the 2010 time frame, two significant changes will occur:

1. most affected SGLS sites could be modified for SATOPS in an additional uplink band thus

allowing the flexibility of alternate frequency use for more recent launches, (provided that no

satellite or ground system program experienced delays) and

2. the IMT-2000 system build-out may have achieved levels that will quite likely result in the

inability to reliably close the TT&C command uplink.

Regardless of the alternate frequency capabilities at the ground sites available in 2010, SGLS uplinks

will still be required to control many on-orbit satellites. Legacy satellite systems are expected to require

SGLS support through 2020-2025. By 2010 the likelihood for SATOPS uplink receiver degradation

will increase as IMT-2000 nears full forecasted build out. Under these conditions, assured spectrum

access alone will not preclude the impact to spacecraft/payload commanding and the associated satellite

mission due to increased background power spectral density.
DoD IMT-2000 Assessment

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B.4.2 Technical Assessment

B.4.2.1 Interference from Ground Elements to IMT-2000

B.4.2.1.1 Assessment Approach

In order to assess the potential for interference to a geographically dispersed network of IMT-2000 fixed

and mobile receivers, an automated model was used to generate received signal overlays as a function of

transmitter and receiver parameters and terrain-dependent path loss. The results are displayed as a raster

or grid of color-coded signal levels overlaid on a map. The basis for the terrain-dependent path loss

calculations within the model is the Terrain-Dependent Path Loss Model (TIREM). This model considers

obstructions due to terrain but does not consider additional losses due to man-made structures or foliage.

In recognition of the significant variations in SATOPS transmitter uplink and IMT-2000 receiver

configurations, a parametric analysis was performed. For SATOPS uplink functions, minimum antenna

elevation angles of 3, 5, and 10 degrees were selected for comparative analysis purposes only. However,

10 degrees is not acceptable from an operational perspective. Additional higher minimum elevation

angles were not considered because the minimal benefit in sidelobe reduction was offset by the significant

impact to operations. Based on current antenna configurations, significant sidelobe reduction is not

realized until well outside of the mainbeam. These angles would be prohibitively large for typical

SATOPS functions, particularly for those conducted on satellites flying in non-geostationary orbits.

For the IMT-2000 receivers, separate overlays were generated for the base stations and mobiles/portables

in recognition of the differences in receiver antenna height, antenna gain, and interference threshold.

B.4.2.1.2 Analysis

The following equation was used to define the regions surrounding the SATOPS uplink sites where

impact to IMT-2000 receivers may occur.

I = Pt + Gt + Gr - Lp - Ls- FDR

where

I = Assumed interfering signal level, at the IMT-2000 receiver input, in dBm

Pt = SATOPS transmitter power, in dBm

Gt = SATOPS transmitter antenna gain at the horizon, in dBi
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Gr = IMT-2000 receiver antenna gain in the direction of the SATOPS transmitter, in dBi

Lp = Terrain-dependent path loss, in dB

Ls = IMT-2000 receiver system loss, in dB

FDR = Frequency-dependent rejection, in dB.

Given that the interference estimate varies as a function of the SATOPS transmitter/antenna configuration

and IMT-2000 receiver susceptibility thresholds, a parametric assessment was performed for several

representative SATOPS uplink sites. Table B-7 lists the SATOPS uplink sites included within this

assessment. These sites were selected to represent a variety of functions, orbit types, and local terrain

features over a geographically dispersed region. It is expected that the results achieved for these sites are

generally representative of the potential for EMI at all SATOPS uplink sites.

Table B-7. SATOPS Uplink Sites Included in this Assessment

Terminal Name Abbreviation Alt Name Location

Latitude/

Longitude

Number of

Terminals

Terminal Size

(feet)

Colorado Tracking Station CTS Pike Colorado Springs, CO 38 48 21 N

104 31 43 W 1 33

New Hampshire

Tracking Station NHS Boss Manchester, NH 42 56 52 N

071 37 37 W 3

60

46

33

Onizuka Air Station OAS Sun Sunnyvale, CA 37 24 25 N

122 0134 W 1 51

Eastern Vehicle Check-out

Facility EVCF EVCF Cape Canaveral, FL 28 27 29 N

080 34 32 W 1 23

Hawaii Tracking Station HTS Hula Kaena Point, Oahu, HI 21 33 48N

158 14 54W 2 60

46

Guam Tracking Station GTS Guam Anderson AFB Guam 13 36 54N

144 52 00E 2 60

46

Transmitter maximum powers in Table B-8 represent the maximum transmitter capability of the high

power amplifier connected to the terminal. A minimum power of 100 Watts was selected to represent

best-case EMI uplink powers under the assumption that link closure can be achieved at this level. In

many instances, a transmit power of 250 Watts, 500 Watts, or even 1 kW is required for link closure to a

healthy, stable, on orbit satellite. However, results from the overlays will indicate that several dB of

variation in the transmit power assumptions will not change the conclusions that can be drawn from the

data.

Antenna off-axis gains were determined from computer generated antenna patterns. Antenna off-axis

gain at the horizon was calculated assuming 3, 5, and 10-degree minimum elevation angles. As discussed

in the approach, these levels are considered to be within the range of acceptable values for analysis

purposes. From an operations concept perspective, 3 degrees is acceptable, 5 degrees is acceptable for

select missions, and 10 degrees is operationally unacceptable. Figures B-2 through B-5 are computer
DoD IMT-2000 Assessment

B-18

generated antenna patterns for the 60, 46, 33, and 23-foot antenna diameters. These figures were used to

calculate the off-axis antenna gains at the 3, 5, and 10-degree minimum elevation angles.”

Table B-8. SATOPS Model Inputs

Antenna off-axis gain

(dBi)

Effective Isotropic Radiated

Power (EIRP) (dBm)

Terminal

TX Powers

(Watts)

Antenna

Diameter

(ft) 3o 5o 10o 3o 5o 10o

CTS 2.25K max/100 min 33 8 5 3 72/58 69/55 67/53

NHS

10K max/100 min

2.5K max/100 min

1K max/100 min

60 (A)

46 (B)

33 (DLT)

24

18

8

17

5

5

12

3

3

91/71

82/68

68/58

87/67

69/55

65/55

82/62

67/53

63/53

OAS 2K max/100 min 51 (DLT) 18 5 3 81/68 68/55 66/53

EVCF 2.25K max/100 min 23 23 16 12 87/73 80/66 76/62

HTS* 2K/500/100 46 18 3 81/75/68 66/60/53

Guam* 7Kmax/100 min 46** 18

No

Analysis 3 90

No

Analysis 59

(A), (B), and (DLT – Data Link Terminal) are designators used to differentiate between unique site locations.

*Only a limited set of conditions were considered for the HTS and GTS sites.

**The actual configuration for the Guam site is a 7K maximum power, with a 60-foot antenna. The 46-foot

diameter was used for model inputs.

Table B-9 lists the IMT-2000 data used to generate the received signal overlays. This data has been

coordinated with the FCC and is consistent with IMT-2000 system specifications used to assess the other

types of DoD systems in the band. Receiver interference thresholds are grouped into 10-dB bins from the

most sensitive threshold provided (-121 dBm) up to greater than -71 dBm. This range of thresholds more

than encompasses the region of acceptable interference values.

Table B-9. IMT-2000 Receiver Data

IMT-2000

Platform

Receiver Interference

Thresholds Plotted (dBm)

Receiver Antenna

Height (Meters)

Receiver Antenna

Gain (dBi)

Fixed Base

Stations

<-121

-111 to –121

-101 to –111

-91 to –101

-81 to –91

-71 to –81

> -71

40 17

Mobiles and

Portables

<-105

-95 to –105

-85 to –95

-75 to –85

>-75

1.5 0
DoD IMT-2000 Assessment

B-19

Angle (Degrees)

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180

ARTS 60' Antenna: Gain vs. Angle

Gain (dB)

-50

-40

-30

-20

-10

0

10

20

30

40

50

Feed and Spar

Blockage Spar

Scattering

Peak Gain = 49.3 dB

Freq = 1.8 GHz

Range = 2.5 Miles

Far-Field = 2.5 Miles

 

Prime Fed Paraboloid:

Inclues feed blockage

and secondary spar 

blockage and scattering.

Raytrack

Parabolas:Arts60a.f

Time: Thu Oct 05 16:16:39 2000 Arts001005f.pgw

Figure B-2. Computer Generated Antenna Pattern for the Automated Remote Tracking Station

(ARTS) 60-foot Antenna Diameters (Antenna Gain Values are in dBi)
DoD IMT-2000 Assessment

B-20

ARTS 46' Antenna: Gain vs. Angle

-40

-30

-20

-10

0

10

20

30

40

50

Gain (dB)

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180

Angle (Degrees)

Peak Gain = 47.0 dB

Freq = 1.8 GHz

Range = 7.3 Miles

Far-Field = 1.5 Miles

Raytrack

Cassegrains:Arts46b.f

Arts001003d.pgw

Time: Tue Oct 03 12:12:27 2000

Figure B-3. Computer Generated Antenna Pattern for the 46-foot Antenna Diameters

(Antenna Gain Values are in dBi)
DoD IMT-2000 Assessment

B-21

Figure B-4. Computer Generated Antenna Patterns for the 33-Foot Antenna Diameters

(Antenna Gain Values are in dBi)

33 Ft. Cassegrain Antenna: Gain vs. Angle

-40

-30

-20

-10

0

10

20

Gain (dB)

30

40

50

Angle (Degrees)

0 5 10 15 20 25 30 35 40 45 50 55 60

Range (Miles)

R = 0.5

R = 5.0

Frequency = 1.8 GHz

Far-Field = 0.75 Miles

Raytrack

Cassegrains:Rh33ft1.f

Rh33ft001002d.pgw

IGRID=3, WLAMBDA=1.0

Time: Tue Oct 03 12:49:29 2000
DoD IMT-2000 Assessment

B-22

-30

-20

-10

0

10

20

30

Gain (dB)

40

50

Angle (Degrees)

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180

Datron 23' Antenna: Gain vs. Angle

Freq = 1.8 GHz

Peak Gain = 40.7 dB

Range = 0.4 Miles

Far-Field = 0.4 Miles

 

Prime Fed Paraboloid:

Includes feed blockage

and secondary spar

blockage and scattering

Spar

Scattering

Time: Fri Oct 06 16:12:44 2000

Raytrack

Parabolas:Dia23ft1.f

Dia23ft001006d.pgw

Figure B-5. Computer Generated Antenna Patterns for the 23-Foot Antenna Diameters

(Antenna Gain Values are in dBi)

B.4.2.1.3 Results

Results of the signal level predictions for the six sites analyzed, CTS, NHS, OAS, EVCF, Hawaii, and

Guam, are contained in Attachment 1. Three-dimensional topographic displays of the regions

surrounding the sites are included to illustrate the relationship between terrain and predicted received

signal level. The signal level plots do not reflect any additional attenuation due to blockage from manmade structures. In dense urban areas man-made structures may provide an additional 10-20 dB of

attenuation which could reduce the interference to mobile stations with low antenna heights. Several plots

are included within this section for discussion. A legend in the upper right corner of the overlays defines

the IMT-2000 received threshold plotted. It should be noted that the –121 dBm threshold, which is

depicted as white in the legend, is portrayed as yellow on the overlays. Below the legend are all of the

input parameters used to generate the overlay.
DoD IMT-2000 Assessment

B-23

Figure B-6 is an overlay for the worst-case conditions at NHS: maximum transmitter power (10 kW), and

minimum elevation angle (3 degrees). Worst case overlay conditions apply to the IMT-2000 base stations

vice the mobiles due to the increased antenna height (40 meters) and higher antenna gain (17 dBi)

associated with the fixed sites. As shown in the figure, no region within the 70 X 70 km area shown

meets the -121 dBm threshold. In fact, virtually all of the area depicted in the overlay experiences levels

in excess of -71 dBm, well in excess of what might be considered a reasonable threshold level for the

IMT-2000 receivers. Figure B-7 depicts the coverage for the same site under best-case transmitter

conditions, 100 Watt transmitter power, and a 10-degree minimum elevation angle. While there is a noted

reduction in the region exposed to levels in excess of -71 dBm, there is still no area that meets or even

approaches the -121 dBm threshold specified. Figure B-8 depicts the best case overall (from an

interference perspective) in that it depicts signal levels to a mobile receiver (reduced antenna height and

antenna gain) at the lowest SATOPS transmit power and highest antenna elevation angle. Under these

conditions, significant improvement is noted from the previous overlays; however, there are still

significant portions that extend out 70 km and beyond from the site that exceed the -105 dBm threshold.

Figure B-6. NHS-A, Antenna Elevation Angle: 3°, Transmitter Power: 10,000 W, IMT-2000

Base Station
DoD IMT-2000 Assessment

B-24

Figure B-7. NHS-A, Antenna Elevation Angle: 10°, Transmitter Power: 100 W, IMT-2000

Base Station
DoD IMT-2000 Assessment

B-25

Figure B-8. NHS-A, Antenna Elevation Angle: 10°, Transmitter Power: 100 W, IMT-2000

Mobile Station

A review of the other sites analyzed produces similar results. Figure B-9 represents worst-case SATOPS

uplink conditions (maximum power, low elevation angle) for the OAS site. Like the NHS overlays,

signals in excess of -71 dBm extend well beyond 70 km from the uplink terminal. Under these

conditions, electromagnetic interference (EMI) from OAS extends well beyond the highly populated and

highly desirable market regions of Oakland and San Francisco. Even under best case conditions

(10 degrees and 100 Watts), Figure B-10 illustrates that the areas in excess of -121 dBm extend well over

75 km from the site. Figure B-11 depicts impact to IMT-2000 mobile users under best-case SATOPS

uplink conditions. Like the NHS case, this represents the smallest potentially affected area. However, the

region impacted still encompasses highly desirable regions from an IMT-2000 market perspective.

One exception to the overlay results applies to the IMT-2000 mobiles surrounding the Hawaii Tracking

Station. At this location, terrain plays a significant role in attenuating the SATOPS undesired signal

levels in the populated areas of Oahu. Hence the potentially affected area is fairly limited. Figure B-12

illustrates that the impact to IMT-2000 mobiles on Oahu with a SATOPS transmitter power of 500 Watts

and a 10-degree antenna elevation angle. Most portions of the Island meet the desired interference

threshold of -105 dBm.
DoD IMT-2000 Assessment

B-26

Figure B-9. OAS, Antenna Elevation Angle: 3°, Transmitter Power: 2,000 W, IMT-2000 Base Station

Figure B-10. OAS, Antenna Elevation Angle: 10°, Transmitter Power: 100 W, IMT-2000 Base Station
DoD IMT-2000 Assessment

B-27

Figure B-11. OAS, Antenna Elevation Angle: 10°, Transmitter Power: 100 W, IMT-2000

Mobile Station

It should be noted that the assessment assumes 360-degree coverage for the HTS SATOPS antenna.

While for many sites this is true (including NHS), there are some sites that do concentrate activities

within specific azimuth ranges, thereby lessening the effects to IMT-2000 receivers at large off-axis

angles relative to the SATOPS mainbeam. It is also worthy of note that SATOPS uplink terminals only

transmit on one channel at a time thereby lessening the impact to IMT-2000 users on nearby operating

frequencies. This fact, coupled with the specific antenna azimuth operations, allows for the possibility of

sharing on a time/frequency basis.

To illustrate the variation in impact as a function of azimuth for a fixed pointing antenna, four additional

plots were generated. Figures B-13 and B-14 illustrate the base and mobile received signal levels for a

2000-Watt SATOPS uplink power and a 3-degree elevation angle. Figures B-15 and B-16 illustrate the

base and mobile received signals for a 10,000-Watt SATOPS uplink power and a 3-degree elevation

angle, plus an additional 50 dB of signal attenuation. In all four instances the antenna was fixed in

azimuth at 33 degrees.
DoD IMT-2000 Assessment

B-28

Figure B-12. HTS, Antenna Elevation Angle: 10° Transmitter Power: 500 W, IMT-2000

Mobile Station

As expected, the plots illustrate that impact to IMT-2000 receivers in the far sidelobes and backlobe of the

SATOPS antenna is far less than that closer to the mainbeam. This factor should be taken into

consideration when exploring mitigation techniques and frequency sharing options. It is also apparent

that the benefits realized from raising the minimum elevation angle are primarily in the regions

surrounding the mainbeam and first sidelobes.
DoD IMT-2000 Assessment

B-29

Figure B-13. OAS, Antenna Elevation Angle: 3°, Azimuth 33°, Transmitter Power: 2000 W,

IMT-2000 Mobile Station
DoD IMT-2000 Assessment

B-30

Figure B-14. OAS, Antenna Elevation Angle: 10°, Azimuth 33°, Transmitter Power: 2000 W,

IMT-2000 Mobile Station
DoD IMT-2000 Assessment

B-31

Figure B-15. NHS-A, Antenna Elevation Angle: 3°, Transmitter Power: 10,000 W, IMT-2000

Base Station, Plus an Additional 50 dB of Signal Attenuation
DoD IMT-2000 Assessment

B-32

Figure B-16. NHS-DLT, Antenna Elevation Angle: 10°, Transmitter Power: 100 W, IMT-2000

Mobile Station, Plus an Additional 50 dB of Signal Attenuation

SATOPS uplink power management, antenna elevation angle restrictions, and frequency off tuning help

to reduce the affected area around the SATOPS uplink transmitter. However, if coordination regions on

the order of 10 to 20 km are desired, and IMT-2000 specified interference thresholds are to be met, an

orders of magnitude decrease in the undesired signal level will be required. Additional measures for

reducing the uplink power at the IMT-2000 receiver coupled with power management and antenna

restrictions must be implemented to significantly limit the affected area surrounding the uplink site.

B.4.2.1.4 SATOPS Uplink to IMT-2000 Receivers Interference Mitigation Measures

Based upon the results of the signal level predictions, it is apparent that additional signal attenuation is

required if sharing between the services is desired. Potential mitigation techniques fall into one of three

categories: measures implemented solely by the DoD SATOPS community, measures implemented

solely by the IMT-2000 industry, and those techniques that require mutual implementation by both

parties. The following measures are presented for discussion and consideration. It is important to note

that not all costs of these mitigation techniques have been estimated. Employing any of these techniques
DoD IMT-2000 Assessment

B-33

would require a cost assessment and could dramatically alter the cost estimates presented earlier.

Further analysis is warranted to address viability, cost, and implementation issues.

B.4.2.1.4.1 DoD EMI Mitigation Techniques

Relocation of the SATOPS Uplink Antennas and/or SATOPS Transmission Off-loading.

Some of the current SATOPS terminals around the world are located in remote areas such as Diego

Garcia and Thule, Greenland. It is expected that these regions will have a relatively low IMT-2000 user

density. There are, however, several stations, such as New Hampshire or Sunnyvale, located near

population centers. For sites such as these, it may be useful to consider the cost and mission impacts of

moving the tracking stations, including antennas, and operations and maintenance personnel to more

remote locations with lower population densities that are less desirable from an IMT-2000 market

perspective. Similarly, where satisfactory visibility can be achieved, it may be possible that some of the

operations currently performed by terminals in populated areas could be off-loaded to more remote

terminals. It must be emphasized that relocating tracking stations and their antennas requires both time

and additional funding to achieve frequency protection, negotiate international agreements, perform

construction, and to acquire and install the SATOPS systems. Based on existing military construction

funding rules, Congressional review would be required for each affected site.

Reduction of the Out-of-Beam Energy of the SATOPS Antennas. Assuming that the

mainbeam emissions are highly focused in the SATOPS antennas, some control of the radiation in the

direction of the victim receivers would be beneficial. The most common approaches to this are (1)

antenna elevation angle restrictions and (2) intentional signal blockage and antenna redesign.

SATOPS Antenna Elevation Angle Restrictions. Like power management, restricting the

minimum elevation angle serves to limit the power at the horizon and hence reduce the undesired signal

into the IMT-2000 receiver. As illustrated in the overlays, a 10-degree minimum elevation angle

reduced the size of the affected areas. However, even when coupled with power management, these

measures are insufficient to reduce EMI regions to expected acceptable levels.

Signal Blockage and Antenna Redesign. Intentional signal blockage can be achieved via a

cylinder surrounding the dish to reduce spillover, modification of the feed, or modification of the

illumination taper to reduce sidelobes at the expense of gain.

SATOPS Power Management. SATOPS transmit power capabilities typically vary over a wide

range from as low as 100 Watts to as much as 10 kW. The high-power transmissions are typically
DoD IMT-2000 Assessment

B-34

reserved for emergency operations but are also radiated periodically for system checkout and training.

Link closure can typically be achieved at powers in the 100 to 500 Watt range for satellites on orbit and

under nominal operating conditions. As indicated in the signal level predictions, power management

does not in of itself solve the EMI problem; however, it does reduce the size of the affected regions.

It should be noted that this mitigation technique might not be possible if IMT-2000 emissions cause EMI

to satellite receivers and it becomes necessary to increase the power output of the ground terminal to

overcome the interference. Further, it should be noted that any increase in the transmitted power, to

reduce interference to the satellites, would have adverse effects on any collocated 3G capability.

B.4.2.1.4.2 IMT-2000 EMI Mitigation Techniques

Establishment of Keep-Out Zones. Short of complete frequency separation, there is a potential for

EMI to a mobile user (or fixed base station) if it is allowed to operate in proximity to an SATOPS uplink

transmitter. The signal level overlays clearly show the potential size of the affected areas. The

possibility of some keep-out zone, even if only a few kilometers surrounding the site, should be

considered to help mitigate the most challenging close in interactions.

Base Station Antenna Nulling. It is expected that IMT-2000 antenna implementation may be

similar to the current cellular/PCS designs; three-direction antenna segments each covering a 120-degree

sector. This scheme introduces the possibility to add an additional highly directive antenna in the

direction of the SATOPS terminal and to use that signal to null out the received signals on the

broadbeam antenna in the direction of the SATOPS terminal. The hole in coverage created by this

scheme could then be filled via an alternate antenna at a location such that a mainbeam interaction with

the SATOPS terminal is avoided.

Polarization Discrimination. Polarization discrimination mitigation takes advantage of the fact that

the mobile signals are linearly polarized, whereas the SATOPS uplinks are circularly polarized. By

measuring the received polarization and cross polarizing the IMT-2000 base station to that signal, a

significant reduction in interference is achievable (20 dB) with only a 3-dB reduction to the mobile

signal. This proposal obviously requires an investment in technology by the IMT-2000 community and

may be practical on a limited scale for base stations in specific problem areas.

B.4.2.1.4.3 Mutual EMI Mitigation Techniques

Cooperative scheduling is an attractive EMI mitigation technique that offers a potential benefit if mutual

agreement and coordination with the IMT-2000 industry can be achieved. Cooperative scheduling is not
DoD IMT-2000 Assessment

B-35

unlike band segmentation in that both approaches look toward frequency separation between the systems

as a technique for minimizing the potential for EMI. Note however the significant distinction between

cooperative scheduling, which assumes sharing of the entire SGLS uplink band via real-time frequency

deconfliction, and band segmentation, which assumes separation of systems into distinctly separate

portions of the spectrum. Unlike band segmentation, cooperative scheduling addresses EMI issues

associated with uplinks to currently flying systems for which only one S-band channel is available for

TT&C. In these instances, there is essentially no flexibility in terms of spectrum use from the SATOPS

perspective.

Cooperative scheduling takes advantage of the fact that SATOPS operations only use a limited amount

of spectrum at any given instant in time. That, coupled with the specific antenna pointing required for a

satellite contact, limits the affects on the environment. Therefore, at any instant, only a relatively small

portion of the IMT-2000 network maybe affected. The concept behind cooperative scheduling is to

allow the IMT-2000 network to dynamically assign spectrum usage to the network around the SATOPS

uplink transmissions. This technique would require software enhancements and dynamic switching

capabilities for the IMT-2000 systems. It also assumes that the IMT-2000 switching algorithm is fed

information on the SATOPS uplink schedule either in advance via pre-coordination, in real-time via

landline, or by monitoring the environment for SATOPS signal use. The requirement to pass SATOPS

scheduling information to IMT-2000 service providers in turn raises operations securities issues that

need to be addressed. While this mitigation technique is not without its challenges, it takes advantage of

the SATOPS unique time/frequency use of the electromagnetic spectrum and, therefore, could be one of

the more effective techniques to reduce EMI to the IMT-2000 users. This technique will also require

channel filters to be installed at US&P sites.

B.4.2.1.5 Summary

Further study is required to quantify the benefit of the aforementioned mitigation measures. Figures

B-15 and B-16 are provided to illustrate the benefit of mitigation techniques that provide an additional

50 dB of attenuation in the direction of the victim receiver. Note that under the worst-case conditions

for NHS, the affected area improvement is notable but still considerably large.
DoD IMT-2000 Assessment 

B-36 

B.4.2.2 Potential Interference to SATOPS uplinks from IMT-2000 

B.4.2.2.1 Assessment Approach 

The approach was to calculate the estimated interference environment into a spacecraft receiver based 

upon the power flux density per square kilometer per Hertz generated by IMT–2000 stations in an 

urban environment and the population density and urban area sizes visible from the spacecraft. ITU-R 

Recommendation M.687-2 gives the power flux density per square kilometer per Hertz generated by 

IMT-2000 base stations and mobile stations in a urban area. This power flux density was derived from 

an estimation of the spectrum needed for IMT-2000. ITU-R Report M.2023 provides an updated 

estimate of the spectrum required for IMT-2000. The power flux density used in this assessment was 

calculated from the updated spectrum requirements using the same procedure as was used in ITU-R 

Recommendation M.687-2. The power flux density from IMT-2000 base stations in Region 2 (North 

and South America) was calculated to be 41 ΦW/km2

/Hz. The power flux density from IMT-2000 

mobile stations in Region 2 was calculated to be 1 ΦW/km2/Hz. 

In addition to the IMT-2000 base stations in urban areas, some base stations will be deployed in rural 

areas to serve traffic on major highways and to serve small towns. These rural base stations may 

actually employ higher transmitter powers than their urban counterparts since they may be required to 

serve a larger area. The contribution from these rural stations was not considered in this report since 

there was no estimate available of their numbers. The effect of interference from these stations can 

only increase the impact on orbiting spacecraft from the IMT-2000 systems. 

The size of the world’s urban areas and their populations was estimated by taking data from a variety 

of sources, including United Nations statistical data and US Census Bureau data. The 2763 most 

populous urban centers are shown in Figure B-17. 
DoD IMT-2000 Assessment 

B-37 

Figure B-17. Most populous urban centers 

Although it was possible to identify the estimated populations of the 2763 most populous urban areas, 

data regarding their size was only available for less than ten percent of the areas. In order to 

approximate the area of each urban location, the population density of a number of cities can be used, 

and an average inverse population density can be derived. This is shown in Table B-10, and the 

resulting value is used in the computations. 

Table B-10. Approximate population density (inverse) used in the analysis 

City Size (km2) Population (millions) Ratio (km2/ millions) 

New York 780 7.3 106.8 

London 1500 7.0 214.3 

Paris 103 2.2 46.8 

Berlin 891 3.5 254.6 

Mexico 3000 20.9 143.5 

Chicago 591 7.8 75.8 

Toronto 650 5.0 130.0 

Las Vegas 218 1.2 181.7 

Average Ratio 144.2 

A computer simulation program was developed to calculate the estimated IMT-2000 interference 

environment into a spacecraft receiver. The orbit shell is defined by a matrix of spacecraft latitude and 

longitude positions (up to ±90o in latitude, and 360o in longitude). At each position on the orbit shell, 

the database of cities is searched for those that are visible from the spacecraft. Using their 

approximated geographic size, the total interfering power density into the spacecraft receiver is 

calculated from Equation B-1. 
DoD IMT-2000 Assessment 

B-38 

= ∑{ ⋅ [( )⋅( )⋅( )]− ( ) + ⋅ ( ) ⋅ − }

i

i i Le I(dBW / Hz) 10 log 41 W / km / Hz citypop 144.2km / millions 32.44 20 log range freq 2 2 μ

(B-1) 

where 

 citypopi = population of the ith visible city, in millions 

rangei = range to the ith visible city, in km 

freq = 1800 MHz in all calculations 

Le = environmental losses; 10 dB in all calculations 

and, though not shown, values are converted back to linear units before summation. 

A typical satellite link budget from a representative Air Force Satellite Control Network (AFSCN) 

transmitter to a satellite using a common telemetry, tracking, and commanding (TT&C) transponder 

(the L3–Com model CXS810–C) was used to compute the link margin in the absence of interference 

from IMT-2000 transmitters. The aggregate interference level from the IMT-2000 environment was 

then used to compute the net margin. 

B.4.2.2.2 Link Margin calculations 

Four satellite orbits were chosen for the assessment: 

• A 250-kilometer orbit, typical of the Space Transportation System (STS) 

• An 833-kilometer orbit, typical of meteorological satellites such as Defense Meteorological 

Satellite Program (DMSP) 

• A 20,200-kilometer orbit, typical of the Global Positioning System (GPS) 

• A 35,784-kilometer orbit, typical of geostationary satellites 

For the two lowest orbits, two hypothetical AFSCN transmitter powers, 250 W and 2000 W, were used 

in the assessment. For the other two orbits, only the 2000 W power was used. These power levels 

may not be the actual powers normally used in AFSCN operations, but are representative of AFSCN 

capabilities. 

The AFSCN uses a variety of antennas ranging in size from 23 ft to 60 ft. For this assessment, a 33-ft 

antenna with a gain of 41 dBi was selected for the AFSCN station. A spacecraft antenna with a -5 dBi 

gain was assumed as typical. Propagation losses took into account free-space path loss, cloud loss, 

rain loss, atmospheric loss, and polarization loss based on the slant-range to the spacecraft. Three 

AFSCN station elevation angles were used to determine the losses through the earth’s atmosphere. 
DoD IMT-2000 Assessment 

B-39 

A typical SGLS transponder, the L3 Communications CXS-810C, was used to represent the spacecraft 

receiver. The spacecraft effective receiver system temperature was 798° Kelvin. The threshold powers 

were calculated for the Command service and for the Carrier service based on the use of a 0.3 

modulation index for the Command and Ranging signals. 

Link margin calculations considering IMT-2000 interference were based on the IMT-2000 traffic 

loading characteristics of ITU Region 2 (the Americas). Since the power densities per square 

kilometer per Hertz from the other regions differed by less than 1 dB for the Base Stations and by 

approximately 3 dB for the Mobile Stations, it is reasonable to assume that the Region 2 values are 

indicative of the interference environment worldwide. 

An example of the link budget and the net margin calculations is shown in Table B-11. The results of 

the link margin calculations are shown in Tables B-12 through B-19. Analysis results for the ranging 

function are not shown in these tables. The degradation to the command capability is always more 

severe than to the ranging capability. The effect of interference on ranging is to increase the time 

required to integrate the pseudonoise code in order to determine the range. Separate tables are shown 

for interference from mobile stations and base stations for each of the years 2003, 2006, and 2010 as 

well as for a future full buildout of the IMT-2000 system. 
DoD IMT-2000 Assessment

B-40

Table B-11. Typical Link Budget

Freq 1800 MHz

TX Power 2000 Watts

TX Power 63 dBm

TX EIRP 105 dBm

TX Ant Dia 33 Ft

TX Ant Beamwidth 1 Deg

TX Ant Gain 42 dBi

Orbit Height 35784 Kilometers

Elevation Angle 3 Deg

Mean Earth Radius 6378 Kilometers

Slant Range 42220 Kilometers

Space Loss 190 dB

Cloud Loss 0.0 dB

Rain Loss 0.5 dB

Atmospheric Loss 0.6 dB

Polarization Loss 0.5 dB

Scintillation Loss 0.0 dB

Rx Antenna Gain -5 dB

Rx Antenna Temp 300 Deg K

Rx Diplexer Loss 0.3 dB

Rx Coupler Loss 1 dB

Rx Cable Loss 2 dB

Rx Cable Temp 170 Deg K

Total Rx Line Loss 3 dB

Receiver NF 5 dB

Receiver Temp 627 Deg K

Eff Rx Ant Temp 171 Deg K

Rx System Temp 798 Deg K

Rx System Temp 29 dBK

Rx System Gain -5 dB

Rx G/T -34 dB/K

Rx Isotropic Carrier Pwr -95 dBm

CMD Carrier Ranging

Mod Index 0.3 0.3

Mod Loss -14 -1

Threshold Power for a CXS810-C -99 -125 dBm

Data Rate 2000

Link Margin 4 30

System Noise -198 -198 dBW/Hz

IMT-2000 Interference + System Noise -190 -190 dBW/Hz

Net Margin -5 22
DoD IMT-2000 Assessment 

B-41 

Table B-12. Interference from IMT-2000 Mobile Stations in 2003 

Typical Orbit AFSCN Elevation Link Margin Net Margin 

Spacecraft Altitude TX Power Angle Without Interference (dB) With Interference (dB) 

 Command Carrier Command Carrier 

STS 250 km 250 W 3 deg 23.5 50.0 13.5 40.0 

 5 deg 25.0 51.4 15.0 41.4 

 10 deg 27.7 54.1 17.7 44.1 

 2000 W 3 deg 32.6 59.0 22.6 49.0 

 5 deg 34.0 60.4 24.0 50.4 

 10 deg 36.7 63.1 26.7 53.1 

DMSP 833 km 250 W 3 deg 17.4 43.8 13.7 40.1 

 5 deg 18.3 44.8 14.6 41.1 

 10 deg 20.0 46.4 16.3 42.7 

 2000 W 3 deg 26.4 52.8 22.7 49.1 

 5 deg 27.4 53.8 23.7 50.1 

 10 deg 29.0 55.5 25.3 51.8 

GPS 20,200 km 2000 W 3 deg 8.0 34.4 7.7 34.1 

 5 deg 8.4 34.9 4.2 34.6 

 10 deg 8.9 35.3 4.5 35.1 

GEO 35,784 km 2000 W 3 deg 3.8 30.2 3.7 30.1 

 5 deg 4.2 30.6 4.2 30.6 

 10 deg 4.6 31.0 4.5 31.0 

Table B-13. Interference from IMT-2000 Mobile Stations in 2006 

Typical Orbit AFSCN Elevation Link Margin Net Margin 

Spacecraft Altitude TX Power Angle Without Interference (dB) With Interference (dB) 

 Command Carrier Command Carrier 

STS 250 km 250 W 3 deg 23.5 50.0 6.5 33.0 

 5 deg 25.0 51.4 8.0 34.4 

 10 deg 27.7 54.1 10.7 37.1 

 2000 W 3 deg 32.6 59.0 15.6 42.0 

 5 deg 34.0 60.4 17.0 43.4 

 10 deg 36.7 63.1 19.7 46.1 

DMSP 833 km 250 W 3 deg 17.4 43.8 6.7 33.1 

 5 deg 18.3 44.8 7.7 34.1 

 10 deg 20.0 46.4 9.3 35.7 

 2000 W 3 deg 26.4 52.8 15.7 42.1 

 5 deg 27.4 53.8 16.7 43.1 

 10 deg 29.0 55.5 18.3 44.8 

GPS 20,200 km 2000 W 3 deg 8.0 34.4 6.8 33.2 

 5 deg 8.4 34.9 7.2 33.7 

 10 deg 8.9 35.3 7.7 34.1 

GEO 35,784 km 2000 W 3 deg 3.8 30.2 3.5 29.9 

 5 deg 4.2 30.6 3.9 30.4 

 10 deg 4.6 31.0 4.3 30.8 
DoD IMT-2000 Assessment 

B-42 

Table B-14. Interference from IMT-2000 Mobile Stations in 2010 

Typical Orbit AFSCN Elevation Link Margin Net Margin 

Spacecraft Altitude TX Power Angle Without Interference (dB) With Interference (dB) 

 Command Carrier Command Carrier 

STS 250 km 250 W 3 deg 23.5 50.0 4.0 30.4 

 5 deg 25.0 51.4 5.4 31.8 

 10 deg 27.7 54.1 8.1 34.5 

 2000 W 3 deg 32.6 59.0 13.0 39.4 

 5 deg 34.0 60.4 14.5 40.9 

 10 deg 36.7 63.1 17.1 43.6 

DMSP 833 km 250 W 3 deg 17.4 43.8 4.1 30.6 

 5 deg 18.3 44.8 5.1 31.5 

 10 deg 20.0 46.4 6.8 33.2 

 2000 W 3 deg 26.4 52.8 13.2 39.6 

 5 deg 27.4 53.8 14.1 40.6 

 10 deg 29.0 55.5 15.8 42.2 

GPS 20,200 km 2000 W 3 deg 8.0 34.4 6.0 32.4 

 5 deg 8.4 34.9 6.5 32.9 

 10 deg 8.9 35.3 6.9 33.4 

GEO 35,784 km 2000 W 3 deg 3.8 30.2 3.3 29.7 

 5 deg 4.2 30.6 3.7 30.2 

 10 deg 4.6 31.0 4.1 30.6 

Table B-15. Interference from IMT-2000 Mobile Stations at Full Buildout 

Typical Orbit AFSCN Elevation Link Margin Net Margin 

Spacecraft Altitude TX Power Angle Without Interference (dB) With Interference (dB) 

 Command Carrier Command Carrier 

STS 250 km 250 W 3 deg 23.5 50.0 3.5 30.0 

 5 deg 25.0 51.4 5.0 31.4 

 10 deg 27.7 54.1 7.7 34.1 

 2000 W 3 deg 32.6 59.0 12.6 39.0 

 5 deg 34.0 60.4 14.0 40.4 

 10 deg 36.7 63.1 16.7 43.1 

DMSP 833 km 250 W 3 deg 17.4 43.8 3.7 30.1 

 5 deg 18.3 44.8 4.6 31.1 

 10 deg 20.0 46.4 6.3 32.7 

 2000 W 3 deg 26.4 52.8 12.7 39.1 

 5 deg 27.4 53.8 13.7 40.1 

 10 deg 29.0 55.5 15.3 41.8 

GPS 20,200 km 2000 W 3 deg 8.0 34.4 5.8 32.2 

 5 deg 8.4 34.9 6.3 32.7 

 10 deg 8.9 35.3 6.8 33.2 

GEO 35,784 km 2000 W 3 deg 3.8 30.2 3.3 29.7 

 5 deg 4.2 30.6 3.7 30.1 

 10 deg 4.6 31.0 4.1 30.5 
DoD IMT-2000 Assessment 

B-43 

Table B-16. Interference from IMT-2000 Base Stations in 2003 

Typical Orbit AFSCN Elevation Link Margin Net Margin 

Spacecraft Altitude TX Power Angle Without Interference (dB) With Interference (dB) 

 Command Carrier Command Carrier 

STS 250 km 250 W 3 deg 23.5 50.0 -3.3 23.1 

 5 deg 25.0 51.4 -1.9 24.5 

 10 deg 27.7 54.1 0.8 27.2 

 2000 W 3 deg 32.6 59.0 5.7 32.1 

 5 deg 34.0 60.4 7.1 33.6 

 10 deg 36.7 63.1 9.8 36.3 

DMSP 833 km 250 W 3 deg 17.4 43.8 -3.2 23.2 

 5 deg 18.3 44.8 -2.2 24.2 

 10 deg 20.0 46.4 -0.5 25.9 

 2000 W 3 deg 26.4 52.8 5.9 32.3 

 5 deg 27.4 53.8 6.8 33.2 

 10 deg 29.0 55.5 8.5 34.9 

GPS 20,200 km 2000 W 3 deg 8.0 34.4 2.9 29.3 

 5 deg 8.4 34.9 3.4 29.8 

 10 deg 8.9 35.3 3.8 30.3 

GEO 35,784 km 2000 W 3 deg 3.8 30.2 1.7 28.1 

 5 deg 4.2 30.6 2.2 28.6 

 10 deg 4.6 31.0 2.6 29.0 

Table B-17. Interference from IMT-2000 Base Stations in 2006 

Typical Orbit AFSCN Elevation Link Margin Net Margin 

Spacecraft Altitude TX Power Angle Without Interference (dB) With Interference (dB) 

 Command Carrier Command Carrier 

STS 250 km 250 W 3 deg 23.5 50.0 -10.3 16.1 

 5 deg 25.0 51.4 -8.9 17.5 

 10 deg 27.7 54.1 -6.2 20.2 

 2000 W 3 deg 32.6 59.0 -1.3 25.1 

 5 deg 34.0 60.4 0.2 26.6 

 10 deg 36.7 63.1 2.8 29.3 

DMSP 833 km 250 W 3 deg 17.4 43.8 -10.2 16.3 

 5 deg 18.3 44.8 -9.2 17.2 

 10 deg 20.0 46.4 -7.5 18.9 

 2000 W 3 deg 26.4 52.8 -1.1 25.3 

 5 deg 27.4 53.8 -0.2 26.3 

 10 deg 29.0 55.5 1.5 27.9 

GPS 20,200 km 2000 W 3 deg 8.0 34.4 -4.1 22.3 

 5 deg 8.4 34.9 -3.6 22.8 

 10 deg 8.9 35.3 -3.1 23.3 

GEO 35,784 km 2000 W 3 deg 3.8 30.2 -1.7 24.7 

 5 deg 4.2 30.6 -1.2 25.2 

 10 deg 4.6 31.0 -0.8 25.6 
DoD IMT-2000 Assessment 

B-44 

Table B-18. Interference from IMT-2000 Base Stations in 2010 

Typical Orbit AFSCN Elevation Link Margin Net Margin 

Spacecraft Altitude TX Power Angle Without Interference (dB) With Interference (dB) 

 Command Carrier Command Carrier 

STS 250 km 250 W 3 deg 23.5 50.0 -12.9 13.6 

 5 deg 25.0 51.4 -11.4 15.0 

 10 deg 27.7 54.1 -8.7 17.7 

 2000 W 3 deg 32.6 59.0 -3.8 22.6 

 5 deg 34.0 60.4 -2.4 24.0 

 10 deg 36.7 63.1 0.3 26.7 

DMSP 833 km 250 W 3 deg 17.4 43.8 -12.7 13.7 

 5 deg 18.3 44.8 -11.8 14.7 

 10 deg 20.0 46.4 -10.1 16.3 

 2000 W 3 deg 26.4 52.8 -3.7 22.7 

 5 deg 27.4 53.8 -2.7 23.7 

 10 deg 29.0 55.5 -1.1 25.4 

GPS 20,200 km 2000 W 3 deg 8.0 34.4 -6.6 19.8 

 5 deg 8.4 34.9 -6.2 20.3 

 10 deg 8.9 35.3 -5.7 20.7 

GEO 35,784 km 2000 W 3 deg 3.8 30.2 -4.2 22.2 

 5 deg 4.2 30.6 -3.8 22.6 

 10 deg 4.6 31.0 -3.4 23.0 

Table B-19. Interference from IMT-2000 Base Stations at Full Buildout 

Typical Orbit AFSCN Elevation Link Margin Net Margin 

Spacecraft Altitude TX Power Angle Without Interference (dB) With Interference (dB) 

 Command Carrier Command Carrier 

STS 250 km 250 W 3 deg 23.5 50.0 -13.3 13.1 

 5 deg 25.0 51.4 -11.9 14.5 

 10 deg 27.7 54.1 -9.2 17.2 

 2000 W 3 deg 32.6 59.0 -4.3 22.1 

 5 deg 34.0 60.4 -2.9 23.6 

 10 deg 36.7 63.1 -0.2 26.3 

DMSP 833 km 250 W 3 deg 17.4 43.8 -13.2 13.2 

 5 deg 18.3 44.8 -12.2 14.2 

 10 deg 20.0 46.4 -10.5 15.9 

 2000 W 3 deg 26.4 52.8 -4.1 22.3 

 5 deg 27.4 53.8 -3.2 23.2 

 10 deg 29.0 55.5 -1.5 24.9 

GPS 20,200 km 2000 W 3 deg 8.0 34.4 -7.1 19.3 

 5 deg 8.4 34.9 -6.6 19.8 

 10 deg 8.9 35.3 -6.2 20.3 

GEO 35,784 km 2000 W 3 deg 3.8 30.2 -4.7 21.7 

 5 deg 4.2 30.6 -4.3 22.2 

 10 deg 4.6 31.0 -3.9 22.6 
DoD IMT-2000 Assessment 

B-45 

B.4.2.2.3 Summary 

Interference from IMT–2000 base stations is much more severe than from the mobile stations, but both 

represent potentially significant interference to SATOPS. The potential for interference is most 

evident at the low orbits for many of the less favorable operational scenarios. On average, the 

geostationary orbit interference will be quite severe. The negative net margins predicted indicate that 

cochannel sharing with IMT-2000 base stations may not be feasible for some systems even in the early 

stages of IMT-2000 implementation if the predicted levels of interference are realistic. Carrying that 

assumption forward for the 2006 timeframe, interference in all orbits is expected. Sharing with mobile 

stations will be less of a problem. Increasing transmitter power will minimize the interference on the 

uplink, but will increase interference to IMT-2000 receivers. Therefore, this has little practical benefit. 

The satellite characteristics and performance requirements used in this assessment are representative of 

typical characteristics of US military space systems. For specific space programs the actual 

characteristics may vary. Also, SATOPS terminal values used were also considered to be 

representative of current systems, but future systems may use smaller antennas and may not have the 

power capability assumed for this analysis. Therefore, results will vary as specific ground and space 

systems differ, but this analysis is indicative of the magnitude of the problem. 

Because this is a key element in any decision, a more comprehensive study is necessary. As stated 

previously, the assessment results presented in this report are based on a near worst-case scenario. 

Interference caused by introducing 3G users into the 1755-1850 MHz band can potentially have severe 

impacts to DoD satellite operations. DoD will continue to examine the impacts by conducting more 

comprehensive assessments to determine the impacts to DoD satellite missions. 

An estimate of the magnitude of the variation in the link results may be determined by using the 

variations given in Table B-20. 
DoD IMT-2000 Assessment 

B-46 

Table B-20. Tolerances on Link Margin Calculation 

Factor Value 

Used 

Upper 

Bound 

Lower 

Bound 

Explanation 

EIRP 111.5 dBm 116 dBm 104 EIRP is different at different RTS due to antenna 

size; Modernization contract for 2004 and beyond is 

limited to 104 dam at most RTS, 110 dBM at 4 sites 

worldwide 

Receive Antenna 

Gain 

-5 dBi 0 dBi -17 dBi Spacecraft antenna patterns differ; most contain null 

between Zenith and nadir. Depends on definition of 

gain at edge of coverage 

Receive Losses 3.3 dB 5 dB 1 dB Depends on spacecraft design; i.e coupler or no 

coupler, diplexer loss, cable length. 

Receiver NF 5.0 dB 6.0 dB 2.0 dB Depends on vendor and state of the art when that 

spacecraft was built 

Threshold 

Sensitivity 

(at 2Kbps & 

Mod index of .6 

Cmd: -

104.7dBm 

Carrier: -

124.8 dBm 

-98 dBm 

-120dBm 

-132dBm 

-126dBm 

Depends on vendor and state of the art when that 

spacecraft was built. Also directly dependent on mod 

index and data rate 

Mod index 0.3 1.0 0.3 Depends on System design for a particular program 

Mod Loss --14 dB -2.3dB -14 dB Depends on mod index 

Data Rate 

Effect of data 

Rate on margin 

2.0 Kbps 1.0 Kbps 

 

3 dB 

10 Kbps 

-7 dB 

Depends on System design for a particular program 

B.5 OPTION 2 – BAND SEGMENTATION/PARTIAL BAND SHARING 

B.5.1 Operational Impact 

In general, all of the operational impact statements regarding the full band sharing and denied 

spectrum access apply to those portions of the band segmented for non-government use. By retaining 

1755-1805 MHz for exclusive US Government use, SGLS channels 12 through 20 would potentially 

become shared with non-government users. Should this be implemented, assured access would still 

be required for the entire 1755-1850 MHz band (including the 1805-1850 MHz portion) to support 

the on-orbit assets utilizing the shared spectrum. Without such access, TT&C functions would be 

jeopardized and resultant satellite/payload and mission failure could occur as described above. 

Assuming SATOPS access to the non-government portion of the spectrum is retained, the mitigation 

techniques and operational impacts associated with the full band sharing option would apply. This 

includes those issues associated with impact to the SATOPS uplink from IMT-2000 noise levels 

emanating from the surface of the earth as a function of the IMT-2000 build out schedule. Impacts of 

course would be limited to those satellite systems operating in the spectrum occupied by nongovernment users. In a few rare exceptions, systems possessing two TT&C frequencies may be able 
DoD IMT-2000 Assessment 

B-47 

to mitigate RFI by operating on a channel in the government-only portion of the band if applicable. 

In addition to the aforementioned mitigation options, it may be necessary to implement SATOPS 

transmitter filtering on those exclusive government channels adjacent to the non-government 

spectrum. 

The satellite systems currently utilizing or scheduled to use SGLS channels 12-20 include DSCS, 

Milstar, FLTSAT, DMSP, ISR, TE, Advanced EHF, Wideband Gapfiller Satellite (WGS), UHF 

Follow-On (UFO), SBIRS, and MSX. For the satellites ready for launch or already on-orbit, their 

uplink frequencies are fixed. Inability to use those frequencies without interference will eventually 

cause mission failure. DSCS, Milstar, and UFO satellites already built or on-orbit are expected to 

remain operational past 2017. Mission capabilities potentially impacted include communications 

systems and space-based surveillance systems. Therefore, in the 2010 time frame, there will still be a 

large number of on-orbit satellites that require SGLS channel 12-20 for operations. 

B.5.2 1755-1805 MHz Retained – Technical Assessment 

This option would allow retention of SATOPS functions in the 1761-1805 MHz band (SGLS 

channels 1-11) and IMT-2000 operations in the 1805-1850 MHz band. This option would reduce the 

potential for electromagnetic interference (EMI) by maintaining a frequency separation between 

transmitters and receivers. Given that SATOPS functions currently support satellites operating 

throughout the 1761-1842 MHz band, a segmentation scheme alone would reduce but not eliminate 

the potential for EMI to IMT-2000 receivers. The potential for EMI would remain for those systems 

operating in the IMT-2000 portion of the spectrum (SGLS channels 12-20) until the requirement to 

support such satellites no longer exists and the band can be vacated. In some instances however, 

satellite programs are supported via two S-band channels. This introduces the added benefit of 

frequency flexibility and provides an EMI mitigation possibility if one of the two channels lies 

outside the IMT-2000 spectrum. Finally, for those satellites that have not yet been launched, the 

opportunity exists to outfit the vehicle with SATOPS transponders in the band segment allocated for 

TT&C. 

To illustrate the impact of off-tuning the SATOPS uplink and IMT-2000 receivers on the relative size 

of the coordination regions, three sample overlays were generated for the New Hampshire B terminal 

operating at 2.5 kilowatts with a 10 degrees elevation angle. Figures B-18 through B-20 illustrate the 

coordination regions for IMT-2000 base station receivers assuming frequency separations of 4, 8, and 

12 MHz respectively (1, 2, and 3 SATOPS uplink channels). Beyond 12 MHz, the uplink emission 

rolls off gradually such that additional frequency separation yields minimal benefit. 
DoD IMT-2000 Assessment 

B-48 

Figure B-18. Coordination Overlay for 4-MHz Frequency Separation 
DoD IMT-2000 Assessment 

B-49 

Figure B-19. Coordination Overlay for 8-MHz Frequency Separation 
DoD IMT-2000 Assessment 

B-50 

Figure B-20. Coordination Overlay for 12-MHz Frequency Separation 

As can be viewed from the overlays, frequency separation clearly reduces the coordination regions, 

however, like other mitigation techniques discussed, it does not singly provide sufficient isolation 

between the systems to eliminate the potential for EMI. The limited benefit achieved through offtuning is reflective of the typically wide/unfiltered emission spectra in the current SGLS signal 

structure, which is in part due to the unwanted spectral components generated via a class C amplifier. 

Even with a band segmentation scheme additional filtering of the AFSCN terminals will be required 

to mitigate interference to the IMT-2000 systems in the adjacent band. It is expected that the more 

spectrally efficient signal structures that are being considered for future SATOPS uplinks would yield 

greater benefit in a band segmentation scheme. 
DoD IMT-2000 Assessment 

B-51 

B.5.3 1790-1850 MHz Retained – Technical Assessment 

This option would allow retention of SATOPS functions in the 1790-1842 MHz band (SGLS 

channels 8-20) and IMT-2000 operations in the 1755-1790 MHz band. The effects of this option are 

similar to that of Option 2, but a different set of SGLS channels would be affected. Systems 

operating on SGLS channels 1-7 would continue to require support and the potential for EMI would 

remain until the requirement to support such satellites no longer exists. 

B.6 OPTION 3 – PARTIAL BAND SEGMENTATION/OTHER BAND 

COMBINATION 

B.6.1 Operational Impact 

This band sharing scheme involves a phased-in approach granting non-government access to the 

1755-1780 MHz portion of the spectrum in 2006 and access to the 1780-1790 MHz portion of the 

spectrum in 2010. By retaining 1790-1850 MHz for exclusive US Government use, SGLS channels 

1-7 would potentially become shared with non-government users. 

Under this option, there is no impact to SATOPS functions in the 2003 timeframe. By 2006, assured 

access to 1755-1780 MHz portion of the spectrum for SATOPS is required to conduct TT&C for 

those on-orbit assets operating in the affected portions of the band. Without such access, TT&C 

functions in channels 1-7 would be jeopardized and resultant satellite/payload and mission failures 

associated with denied SATOPS spectrum access and SATOPS uplink EMI would occur. The same 

is true for those systems in the 1780-1790 MHz portion of the spectrum (channels 6 and 7) in 2010. 

The satellite systems currently using or scheduled to use SGLS channels 1-5 in the 1755-1780 MHz 

portion of the band include NATO/Skynet, GFO, ISR, DMSP, and SBIRS. The potential interference 

from NATO/Skynet, DMSP, and SBIRS operations can be reduced by use of their alternate channel; 

however, Advanced EHF and GFO lack an alternate channel. Mission capabilities potentially 

impacted include critical US Armed Forces communications and ISR capabilities. 

In 2010, SGLS channels 1-7 would be impacted. Like the other band segmentation options, a lack of 

assured access to this spectrum for SATOPS functions and degradation to the uplink will lead to 

satellite/payload and mission failure. The impacts from RFI mitigation options and IMT-2000 uplink 

EMI parallel those in the previous band segmentation discussions. The satellite systems currently 
DoD IMT-2000 Assessment 

B-52 

using or scheduled to use SGLS channels 1-7 include those mentioned above, plus those using 

channels 6 and 7: GPS, DMSP, NPOESS, and SBIRS. 

B.6.2 Technical Assessment 

If a partial band segmentation option combined with migration of some satellite operations to another 

band is selected, the technical assessments discussed above would apply to the portion of the band 

retained for SATOPS. The technical assessment presented in section B.7.2 would apply to the 

SATOPS migrated to another band. 

B.7 OPTION 4 – VACATE 1755-1850 MHZ 

In addition to considering sharing possibilities between IMT-2000 and DoD systems, the identification 

and assessment of candidate frequency bands for the potential migration of existing and planned DoD 

S-band SATOPS uplink functions is required. This section discusses the issues associated with a 

migration from the current SGLS 1761-1842 MHz band to the band referred to as Unified S-Band 

(2025-2110 MHz). It should be noted that total loss of the band is not possible for space systems until 

at least 2017 or beyond. 

The following are critical assumptions/conditions used when considering the migration of current 

DoD satellite operations to an alternate frequency band: 

• Launch, early orbit, and anomaly (LEO&A) resolution support are critical functions that must 

be maintained throughout the life of a spacecraft 

• Given the current implementations, S-band is uniquely suited for conducting critical, nonroutine SATOPS functions 

• Mission capability provided to end users by US national security space systems will not be 

degraded. The government will maintain assured access to the 1755-1850 MHz band to 

satisfy mission objectives until the last 1755-1850 MHz satellite is no longer functioning. 

This may continue until 2030. 

• Domestic regulatory provisions will be implemented so that the DoD has assured access to the 

2025-2100 MHz band for Launch, Early Orbit Operations and Anomaly Resolution 

(LEO&A), and other operations currently operating in the 1755-1850 MHz band. 

Specifically, the Broadcast Auxiliary Service (BAS) or Electronic News Gathering (ENG) 

services at transportable and mobile locations shall not claim protection from DoD operations 

which have been migrated to the 2025-2100 MHz band. 
DoD IMT-2000 Assessment 

B-53 

• The electromagnetic compatibility (EMC) between SATOPS uplink systems and incumbent 

users of the spectrum must be at least equal to that which currently exists in the SGLS 

frequency band 

• Time must be allotted to make an orderly transition 

B.7.1 Operational Impact 

As indicated, SATOPS functions are absolutely critical for the control and maintenance of the 

spacecraft. Without alternate spectrum to command the satellite, spacecraft and payload failure 

would result. Without the use of SGLS in the US&P after 2003, there would be eventual mission 

failure for a wide range of satellites as described in Option 1. Specific mission functions impacted 

include missile warning, navigation, military communications, weather, and intelligence; surveillance 

and reconnaissance; R&D; and international systems. 

Without the use of SGLS in 2006, similar results would occur, as insufficient time would be allotted 

for launching sufficient dual band satellite capabilities and off-loading TT&C functions to non-US 

sites would not achieve the desired connectivity. All of the systems identified in 2003 would be 

impacted in 2006, including: missile warning, navigation, military communications, weather, and 

intelligence; surveillance and reconnaissance; R&D; and international systems. Even with assured 

spectrum assess, uplink EMI will impact some spacecraft command reliabilities, particularly at the 

LEO and MEO orbits. 

By 2010, there still will be a large number of on-orbit satellites that will require SGLS for operations. 

The operational impact for Advanced EHF, DSCS, Milstar, DSP, UFO, and GPS of turning off SGLS 

in 2010 would be the same as turning it off in 2003. These programs will require SGLS past 2017. 

The FLTSAT, MSX, R&D, and NATO/Skynet programs will have reached end of life, therefore 

there should be minimal to no impact to these programs. The satellites still on orbit requiring SGLS 

during this time frame cannot be adequately supported by non-US&P ground sites and therefore 

would suffer loss of their mission should the US Government be required to vacate 1755-1850 MHz 

by 2010.

B.7.1.1 GPS 

Specific operational impacts associated with the potential loss of various DoD satellites is provided in 

the next subsections. 
DoD IMT-2000 Assessment 

B-54 

Civilian

• Loss of navigation and timing on land, sea, and air 

Military

• Loss of navigation for military applications 

• Loss of GPS aided/guided munitions 

• Loss of GPS aided/guided manned/unmanned aerial platforms 

• Loss of GPS aided/guided manned/unmanned land-based platforms 

• Loss of GPS aided/guided manned/unmanned seaborne platforms 

• Loss of GPS aided/guided manned/unmanned submarine platforms 

• Loss of CSEL used in search and rescue (SAR) and all other SAR-related missions 

Time Transfer Impact

• Loss of global synchronization for a wide range of military and civilian systems 

• Increased risk during aerial refueling rendezvous 

Civilian

• Loss of commercial and private aircraft navigational data increasing risks to safety of flight 

• Loss of required navigational accuracy and signal availability to a huge number of other civil 

users like geo-spatial surveying, emergency vehicle dispatch, agricultural crop rotations, 

oil/petroleum exploration and mapping, and wildlife locations 

Timing Synchronization 

• A significant number of users of commercial applications require precise (GPS) timing. 

• Loss of the required precise timing would severely impact Personnel Communications 

Services capabilities and worldwide financial institutions’ computer operations (including 

automatic bank machines) 
DoD IMT-2000 Assessment 

B-55 

B.7.1.2 DSCS 

• Loss of launch and early orbit capabilities for the remaining DSCS satellites 

• Loss of platform control and the Single Channel Transponder (SCT) capability for DSCS 

• Severe impact to DoD capability to communicate at all levels of conflict 

B.7.1.3 Milstar 

• Severe impact to DoD capability to communicate at all levels of conflict 

• Loss of capability to perform emergency recovery 

B.7.1.4 DSP 

• Degradation of space based missile warning capability, critical to national security 

B.7.1.5 MSX 

• Loss of capability to collect data on deep space orbits of military and commercial satellites 

• Loss of its unique capability to revisit (sightings) on militarily significant objects 

• Impacts ability to reduce the number of lost satellites 

• Increases risk to the space operations (space shuttle and other satellites) due to undetected/lost 

space objects 

B.7.1.6 DMSP 

• Loss of capability to monitor and predict regional and global weather patterns, including the 

presence of severe thunderstorms, hurricanes, and typhoons 

• Loss of imagery of cloud cover 

• Loss of moisture and temperature measurement capability 

• Loss of capability to assess the impact of the ionosphere on early warning radar systems and 

long-range communications 

• Loss of capability to monitor global auroral activity and to predict the effects of the space 

environment on military satellite operations 

• Loss of support to civilian weather bureau 
DoD IMT-2000 Assessment 

B-56 

• Loss of direct support to battlefield units 

B.7.1.7 NATO/Skynet 

• Unable to continue to support longstanding international agreements 

• Unable to perform backup satellite control of the UK's Skynet 4 constellation 

B.7.1.8 FLTSAT/UFO 

• Degradation of capability to perform anomaly resolution, including loss of capability to 

recover from a failure of normal nadir pointing, causing loss of mission capability 

• Loss of critical communications for fleet operations and DoD support for GBS 

B.7.1.9 GFO 

• Loss of platform control for GFO satellite, causing loss of mission capability 

• Loss of capability to measure ocean surface heights 

B.7.1.10 RESEARCH AND DEVELOPMENT SATELLITES 

• Loss of platform control and mission data for the CORIOLIS satellite would result in loss of 

early capability to measure wind surface speed and direction at the ocean surface. Increased 

risk to operational sensor on NPOESS. 

• Loss of platform control and mission data for the C/NOFS satellite would result in loss of 

capability to predict GPS outages as well as outages in ground-space communication links 

due to ionospheric conditions 

• Loss of platform control for Cloudsat will result in loss of capability to profile clouds with 

unprecedented accuracy. Increased risk to future weather predicting sensors. 

B.7.2 Technical Assessment 

B.7.2.1 Frequency Allocation and Regulatory Protection Issues 

From a frequency allocation standpoint, telemetry, tracking and commanding (TT&C) functions fall 

under the category of “Space Operation Service.” Therefore spectrum appropriately allocated for 

space operation would most often be required to secure primary status and maximum regulatory 
DoD IMT-2000 Assessment 

B-57 

protection. It should be noted that frequency allocation provisions currently exist which allow fully 

protected TT&C functions to be conducted on a primary basis in-band with mission data. In some 

instances, DoD satellite programs have elected to, or plan to conduct routine satellite TT&C functions 

in mission bands at considerably higher frequencies. However in most instances, the 1761-1842 MHz 

band is retained as the primary band for conducting daily operations (tracking and telemetry) in 

addition to LEO&A resolution and also as the primary for SGLS operations. 

B.7.2.1.1 SGLS Uplink Frequency Band 

Within the US&P, the 1761-1842 MHz SGLS uplink frequency band is contained within spectrum that 

is reserved for Federal Government use only. This band has primary status for military space 

operation functions (Earth-to-space) via US Footnote G42. The 1761-1842 MHz band shares primary 

status with US Government Fixed and Mobile Services. SGLS frequency use is registered in the US 

Government Master File (GMF) and DoD’s Frequency Resource Record System (FRRS). SGLS 

operations within the US&P are fully compliant with existing national spectrum regulations. SGLS 

use has been coordinated with other federal spectrum users and has full regulatory protection within 

the US. 

Outside the US, the 1761-1842 MHz band is allocated on a primary basis for Space Operation (Earthto-space) in ITU Region 2 (The Americas), Australia, India, Indonesia, and Japan via Footnote S5.386. 

Outside of these areas, space operations functions are not allocated. This band shares primary status 

internationally with the Fixed and Mobile Services (including Aeronautical Public Correspondence: 

1800-1805 MHz). 

In addition to the international regulatory allocation status, the DoD has established Host Nation 

Agreements (HNAs) with the countries within which SGLS operations are conducted. These HNAs 

have been developed to ensure maximum regulatory and RFI protection for SGLS operations overseas. 

Through coordination with host country government/military and civil frequency management 

authorities, the DoD has successfully secured a protected status for existing S-band operations. At the 

international level, the US SGLS uplinks have been registered with the International 

Telecommunication Union (ITU) and have been fully coordinated with all other potentially affected 

satellite systems. Given that the DoD is essentially the only user of the SGLS uplink band for TT&C, 

registration of satellite uplinks requires minimal coordination effort. 
DoD IMT-2000 Assessment 

B-58 

B.7.2.1.2 Unified S-band (USB)

Within the US&P, Unified S-band is contained within spectrum that is shared between government and 

civil users. Although a primary allocation to the Space Operations Service has been added to the US 

National Table of Allocations, US government TT&C transmissions are further governed by footnotes 

US222 and US346.1

 US222 allows for TT&C operations on a co-equal basis in the band 2025-2035 

MHz for uplinks from Geostationary Operational Environmental Satellite Earth stations in the Space 

Research and Earth Exploration Satellite Service. Further these uplinks are limited to three sites within 

the US: Wallops Island, VA, Seattle WA, and Honolulu HI. Footnote US346 restricts uplink 

operations throughout the remaining areas within CONUS by requiring that government space 

operations not constrain the deployment of the non-government fixed and mobile use of the spectrum. 

It requires coordination between government and non-government stations to facilitate compatible 

operations. The primary non-government (civil) user of the band is the Electronic News Gathering 

Systems operating under the Broadcast Auxiliary Service (BAS). NASA and NOAA have coordinated 

government use of USB with the ENG community for TT&C uplinks at specific US sites. 

US346 means that DoD SATOPS uplinks in USB would not have the same degree of regulatory 

protection as currently exists in the 1761-1842 MHz band. This footnote provides the civil operations 

with regulatory priority should successful coordination not be possible and denies assured equal access 

for government space operations. Although over 97% of the ENG systems are transmit only and 

NASA and NOAA have successfully coordinated with these non-government operations, coordination 

with DoD TT&C uplinks may prove more challenging given the number and location of uplink sites, 

coupled with the requirement for greater transmission times, increased bandwidth, and varied antenna 

azimuth/elevation pointing angles. 

Currently, DoD SGLS uplink operations are the incumbent user in the 1761-1842 MHz frequency band 

and as such, new federal spectrum users must demonstrate compatibility with existing SGLS 

operations. In USB however, DoD SATOPS would be required to protect existing incumbent fixed 

users, to coordinate on a continuing basis with and protect existing transportable or mobile users, and 

to coordinate with and not constrain the deployment of future civil users. Therefore, from a regulatory 

 1 US346--Except as provided by footnote US222, the use of the band 2025-2110 MHz by the Government space 

operation service (Earth-to-space), Earth exploration-satellite service (Earth-to-space), and space research service (Earthto-space) shall not constrain the deployment of the Television Broadcast Auxiliary Service, the Cable Television Relay 

Service, or the Local Television Transmission Service. To facilitate compatible operations between non-Government 

terrestrial receiving stations at fixed sites and Government earth station transmitters, coordination is required. To 

facilitate compatible operations between non-government terrestrial transmitting stations and Government spacecraft 

receivers, the terrestrial transmitters shall not be high-density systems (see Recommendations ITU-R SA.1154 and 

ITU-R F.1247). 
DoD IMT-2000 Assessment 

B-59 

protection standpoint, USB does not currently afford the DoD the same status that it currently enjoys in 

SGLS band. If DoD is to enjoy the same protection as in the existing SGLS band, as a minimum, a 

change to US346 must be negotiated. After negotiations are completed, the FCC must, to comply with 

the Administrative Procedures Act (APA), solicit public and industry comments on any possible 

changes to the footnote via a Notice of Proposed Rule Making and Report and Order. 

Internationally, USB shares its primary status with the Earth Exploration Satellite, Fixed, Mobile, and 

Space Research Services. NASA and the international science community as well as others make 

extensive use of this band for uplink TT&C operations. Hence SATOPS uplink functions in USB 

enjoy primary status and regulatory protection overseas. While USB enjoys primary status for TT&C 

overseas, its use for such functions is extensive. Hence the new DoD space operations registrations in 

this band will meet with more international registration/coordination challenges than experienced in 

the current SGLS uplink band, where little if any SATOPS outside the US DoD are performed. The 

challenges will be similar to those currently experienced in registration and coordination of the SGLS 

downlinks. In addition, the requirement for an orderly transition to an alternate band will require 

satellites to be launched with dual mode capabilities as the ground support infrastructure is developed. 

Such dual mode satellites may further complicate registration and coordination procedures. 

B.7.2.1.3 Host Nation Agreements

All operations within a foreign nation’s borders require host nation approval regardless of the ITU 

allocation status. Therefore, the DoD’s migration to USB would require the establishment of a new set 

of HNAs to ensure protected operations on foreign soil. While this may not be an obstacle to success, 

it nevertheless requires new agreements to be established at sites where USB will be used. 

Consideration should be given to the likelihood of successfully completing such HNAs in the overall 

migration assessment. 

B.7.2.1.4 National and International Registrations

A migration to USB will require filing the appropriate national and international registration 

paperwork. With the US, filing of DD Form 1494 Application for Equipment Frequency Allocation as 

well as frequency assignment paperwork will be required. Internationally, registration of the desired 

geostationary nodes for USB with the ITU will be critical. The extensive timeline required for the 

national, and more importantly international registration process requires that these efforts be initiated 

as soon as practical. 
DoD IMT-2000 Assessment 

B-60 

B.7.2.1.5 Government SATOPS Regulatory Issues Summary 

• Domestic regulatory provisions must be implemented so that the DoD has assured access to 

the 2025-2100 MHz band for Launch, Early Orbit Operations and Anomaly Resolution 

(LEO&A), and other operations currently operating in the 1755-1850 MHz band. 

Specifically, the Broadcast Auxiliary Service (BAS) or Electronic News Gathering (ENG) 

services at transportable and mobile locations shall not claim protection from DoD operations 

which have been migrated to the 2025-2100 MHz band. 

• Mission capability provided to end users by US national security space systems must not be 

degraded. The government must maintain assured access to the 1755-1850 MHz band to 

satisfy mission objectives until the last 1755-1850 MHz satellite is no longer functioning. 

This may continue until 2030. 

• Current domestic regulatory provisions that protect existing DoD operations in the 1755-1850 

MHz band must continue throughout any spectrum operations migration/transition period. 

• New HNAs in USB would have to be established. 

• DoD must file and successfully conclude international coordination of satellite networks in 

the 2025-2100 MHz band. 

B.7.2.2 Electromagnetic Compatibility Issues 

B.7.2.2.1 Interference to Incumbent Users – Electronic News Gathering Systems 

System Description.2

 The primary user of the 2025-2110 MHz frequency band by the nonFederal government users is the Electronic News Gathering (ENG) systems operating within the 

Broadcast Auxiliary Service. In addition to the 2025-2110 MHz, ENG systems also operate in the 

6.4-7.1 GHz and 12.77-13.2 GHz bands. This flexibility allows for the possibility of alternate 

frequency band use in instances where SATOPS uplinks are in proximity to ENG receiver sites. 

ENG systems include both mobile point-of-view and transportable ENG systems that provide video 

from a variety of locations and activities. The ENG systems are used for on-location coverage of 

news events or live-action video during sports and entertainment events. The point-of-view systems 

are small light-weight microwave transmitters used for mobile and close-up video. These systems 

utilize essentially omnidirectional antennas with 0-3 dBi of gain with linear or circular polarization. 

The transportable ENG systems are used by most local television stations for on-location coverage 

are generally mounted in vans and operate in a stationary mode transmitting video to a fixed receive 

 2 Document USTG 7-1/102, Analysis of Antenna Gain as a Sharing Criterion between Mobile Services and the 

Space Research Service, Space Operations Service, and Earth Exploration Satellite Services in the 2015-2110 MHz Band, 

Horne, William, D, 10 September 1993. 
DoD IMT-2000 Assessment 

B-61 

site. These systems utilize directional antennas with gains between 20-22 dBi mounted on top of a 

pneumatic mast of up to 15 m in height. ENG systems may employ linear or circular polarization to 

provide additional interference protection from each other. There are also a small number of 

mobile/transportable receivers operating in the BAS service as well (less than 3% of all ENG 

receivers in this band). These mobile/transportable ENG systems are used on helicopters and placed 

in locations with adequate line of sight to relay the broadcast to the base station receiver. 

Although used throughout the day, transportable ENG systems operate primarily during weekday 

local news broadcasts, which usually occur around 1200-1230, 1700-1900, and 2300-2330 local time. 

In most markets before the afternoon news hours around 1500-1700, ENG use is also significant. 

The popularity of local morning shows from 0600-0900 is increasing in various markets, and these 

shows also use ENG systems. Transportable ENG transmitters are operated approximately twice per 

day. Broadcast engineers estimate that each ENG operation transmits an average of 15 minutes per 

operation but can vary from about 5 minutes to perhaps as long as 5 hours. 

The total number of 2 GHz ENG systems in the US exceeds 4000. Although it may seem intuitive to 

assume that all ENG systems would transmit and receive, the vast majority of transportable ENG 

systems (97% according to one ENG manufacturer) posses transmit only capabilities and do not have 

receivers in the 2025-2110 MHz band. Potential victims of interference from SATOPS uplinks are 

therefore generally limited to the much smaller number of fixed receiver sites within the US. 

Table B-21 lists the types of ENG systems typically employed in the US. Figure B-21 shows the 

ENG frequency channelization plan. In the US, the ENG frequency band is divided into seven 

channels each with 17 MHz, except the first channel, which is 18 MHz. ENG systems are usually 

operated at the center of each channel, but the lower offset and upper offset channels are also used. 

Consequently, 21 carrier frequencies are possible, but all carrier frequencies cannot be used 

simultaneously. ENG systems may operate at the center channel, the lower offset channel, the higher 

offset channel, or the lower and higher offset channels simultaneously, depending on the need and 

adjacent channel use at any time. 
DoD IMT-2000 Assessment 

B-62 

Table B-21. Typical 1 GHz ENG systems in use in the United States of America 

+

2 071.75

Channel +

2 088.75

Channel +

2 105.75

Channel 7 +

Channel 1 Channel 2 Channel 3 Channel 4 Channel 5 Channel

–

2 012.25

Channel 2 –

2 029.25

Channel 3 –

2 046.25

Channel 4 –

2 063.25

Channel 5 –

2 080.25

Chann

+

2 054.75

Channel 4 5

el 6 –

2 097.25

Channel 7 –

1 999.00 2 016.50 2 033.50 2 050.50 2 067.50 2 084.50 2 101.50

Channel 1 Channel 2 Channel 3 Channel 4 Channel 5 Channel 6 Channel 7

2 003.25

Channel 1 +

2 020.75

Channel 2 +

2 037.75

Channel 3 6

1 990 2 008 2 025 2 042 2 059 2 076 2 093 2 110

Center carrier frequencie

Offset low carrier frequency (MHz)

Offset high carrier frequency (MHz)

Frequency (MHz)

1 994.75

Channel 1

s

6 Channel 7

(MHz)

Figure B-21. US ENG Frequency Plan

Type of use 

Transmitter 

location 

Transmit 

power 

Antenna 

gain 

(dBi) 

Receiver 

location 

ENG transportable 

 (van) 

Van mast 12 W 22 Tower 

Temporary fixed link Roof 12 W 25 Roof 

Convention Floor of convention hall 100 mW 0-5 Hall rafters 

Point-of-view 

 (e.g., skier) 

On body/helmet 100 mW 0 Hillside or helicopter 

Sports venues 

 Playing field Field 1 W 12 Press box 

 Golf course (system 1) On golf course 3 W 16 Tethered blimp 

 Golf course (system 2) On golf course 12 W 12 Crane 

 Racecam In car 3 W 7 Helicopter 

 Helicopter Relay helicopter 12 W 7 Ground receive 

Marathon 

 Motorcycle Motorcycle 3 W 7 Helicopter 

 Relay vehicle Pick-up truck 12 W 12 Helicopter 

 Helicopter Relay helicopter 12 W 7 Roof 
DoD IMT-2000 Assessment 

B-63 

EMI Assessment. To assess the potential for interference from SATOPS uplinks to ENG 

receivers, calculations were performed to determine the required separation distances between the 

SATOPS uplink sites and the ENG receivers as a function of antenna coupling. The size of the 

required coordination coupled with ENG FCC license data provides an indication of the number of 

systems potentially affected and hence the level of coordination required. The following equation 

was used to estimate the undesired ENG receiver signal level from the SATOPS uplinks: 

Sr = Pt + Gt + Gr - Lp - Ls - FDR 

(B-2) 

where 

 Sr = Undesired signal level, at the ENG receiver input, in dBm 

 Pt = SATOPS transmitter peak power, in dBm 

 Gt = SATOPS transmitter antenna gain at the horizon, in dBi 

 Gr = ENG Receiver antenna gain in the direction of the SATOPS transmitter, in dBi 

 Lp = Path loss, in dB 

 Ls = ENG receiver system loss, in dB 

 FDR = Frequency-dependent rejection, in dB. 

For the analysis, an average SATOPS transmitter uplink power of 2250 Watts was assumed. Off axis 

antenna gains corresponding to minimum elevation angles of 3, and10 degrees were assumed. These 

levels are consistent with the minimum and maximum values used to generate the signal overlays for 

the IMT-2000 receiver analysis. Both a mainbeam gain of 22 dBi and a sidelobe gain of 2 dBi were 

assumed for the ENG receivers. Given the wideband receiver of the ENG systems (17 MHz) as 

compared to the SATOPS uplink signal, no FDR was assumed. A typical receiver sensitivity of -108 

dBm was used as the threshold for interference. The path loss was determined using a smooth-earth 

approximation assuming an ENG antenna height of 30 meters and accounting for the curvature of the 

earth. Table B-22 is a summary of the typical ENG characteristics. Table B-23 contains the 

SATOPS transmitter parameters used in the calculations. 
DoD IMT-2000 Assessment 

B-64 

Table B-22. Parameters of a Typical Electronic News Gathering Systems

Data Value 

Frequency range 1990-2110 MHz 

Transmit power 12 W 

Channel Bandwidth (MHz) 17.0 

Antenna gain 22 dBi (mainbeam), 2 dBi (sidelobe) 

Antenna height 15 m (Transportable), 30 m (Fixed Receive) 

Receiver bandwidth (MHz) 17.0 (-3dB) 

Receiver noise figure 3 dB 

Receiver sensitivity NA 

Receiver noise power -99 dBm 

Interfering signal threshold -108 dBm 

Cable losses 2 dB 

Table B-23. SATOPS Uplink Parameters 

Data Value 

Transmit power 2250 W 

Transmitter Frequency 2075 MHz 

Antenna Size 46 foot 

Antenna Gain 18 dBi (3 degrees); 3 dBi (10 Degrees) 

EIRP 82 dBm (3 degrees); 67 dBm (10 degrees) 

Antenna Feedpoint Height 15 m 

Table B-24 lists the required separation distances as a function of antenna coupling. It should be 

noted that the distances provided do not account for signal attenuation from terrain or man made 

obstructions. These factors in some instances will make the required distance separations 

significantly less. Airborne ENG receivers (relay helicopters) were excluded from this assessment, 

however it should be noted that their usage is an increasing concern to SATOPS. A higher receiver 

antenna height lessons the attenuation from terrain and creates the potential for line of sight (LOS) 

interactions. Under these conditions, separation distances greatly exceed those specified in 

Table B-24 due to the additional line-of-sight distance from airborne platforms. 

Table B-24. Required Distance Separations (km) to Preclude EMI to ENG Receivers 

Required Distance Separations (km) SATOPS Minimum 

Elevation Angle (Degrees) ENG Mainbeam Antenna Coupling ENG Sidelobe Antenna Coupling 

3 201 108 

10 88 59 

Table B-25 lists the approximate number of fixed ENG receivers within the distance separations 

specified in Table B-24. It is apparent that Guam and Colorado may prove to be the least difficult to 

coordinate while ENG activity around the Cape is fairly extensive and therefore will require more 

extensive coordination. The number of receivers indicated in Table B-25 should only be used as an 

indication of the level of coordination required. Several factors including specific channel use, time 
DoD IMT-2000 Assessment 

B-65 

of use, terrain dependent signal attenuation, as well as the possibility of receiver data omission in the 

FCC database will factor into the coordination efforts. Should DoD SATOPS functions migrate to 

USB, a spectrum sharing strategy should be developed in coordination with the ENG community. 

Table B-25. Approximate Number of ENG Fixed Receivers Surrounding SATOPS Uplink Sites 

Approximate Number of Registered ENG Receivers within the Specified Separation 

Requirement 

SATOPS Uplink Site 

201 km Separation 

Requirement 

88 km Separation 

Requirement 

108 km Separation 

Requirement 

59 km Separation 

Requirement 

Manchester, NH (NHS) 22 7 7 7 

Colorado Springs CO (CTS) 2 1 1 1 

Cape Canaveral, FL (EVCF) 34 15 21 11 

Sunnyvale, CA (OAS) 10 2 4 1 

HTS 6 6 6 5 

Guam (GTS) 1 1 1 1 

It should be noted that NASA currently employs SATOPS uplinks within the US that have been 

coordinated with the ENG/BAS community. The DoD should include NASA in its coordination 

activities with the BAS to ensure a unified government approach to band sharing. 

B.7.2.3 EMI Issues Summary 

• There is a potential for EMI from DoD SATOPS uplinks to the ENG services in USB 

• Coordination with the ENG and other communities is essential to preclude EMI 

• Coordination with NASA’s current SATOPS USB uplinks is also recommended 

• A spectrum sharing strategy for USB should be developed in concert with NASA and the 

BAS/ENG community 

• Coordination regions on the order of 50-200 km may be required to address EMI issues to 

fixed ENG receivers. Greater coordination distances may be required when considering 

airborne ENG receivers 
DoD IMT-2000 Assessment

C-1

APPENDIX C – POTENTIAL FOR SHARING BETWEEN

IMT-2000 AND TACTICAL RADIO RELAY IN THE

1755-1850 MHZ FREQUENCY BAND

A large number of existing Department of Defense (DoD) line-of-sight (LOS) microwave (MW)

systems operate in the 1755-1850 MHz frequency band. This appendix addresses the potential for

interference between the International Mobile Telecommunications for the Year 2000 (IMT-2000)

systems and the DoD tactical radio relay (TRR) systems.

The LOS MW systems operating in the band are too numerous to analyze individually, and some of

the fixed systems do not have unique requirements limiting the systems to frequencies below 3 GHz.

One class of systems with requirements constraining operations to frequencies near the 1755-1850

MHz band are the DoD TRR systems, and these systems were analyzed in the assessment.

The military services require efficient methods of exchanging large quantities of digital data

throughout the battlefield. The increased use of computers, digital video, and facsimile equipment in

command and control, intelligence, and logistics will generate more data in the future. The military

radios are deployable, transportable, point-to-point radio systems using low-to-moderate gain

antennas. The military TRR equipment uses broad beamwidth antennas for quick link setup during

deployments. The movement of the lightweight, flexible masts that support the antennas or the

movement of shipboard antennas preclude the use of narrowbeam type antennas. The requirements

for low/moderate power levels for the transportable radios and the broad beamwidth antenna limits

applicable frequency band to below 3 GHz. The primary DoD TRR systems operating in the 1755-

1850 MHz band are the United States (US) Army Mobile Subscriber Equipment (MSE), Tri-Services

Tactical Communications (TRI-TAC), and the Navy/Marine Corps Digital Wideband Transmission

System (DWTS).

C.1 MISSION OVERVIEW

C.1.1 Mobile Subscriber Equipment

The AN/GRC-103, AN/GRC-226, and AN/GRC-245 radio sets are LOS trunk radios used to link

nodes (switching centers) in the Army’s tactical telecommunications system or the Army Common

User System (ACUS). These radios operate in the 1755-1850 MHz spectrum band and would be

degraded by the introduction of IMT-2000 systems into the band. The ACUS is a seamless, tactical

communications system that provides secure, highly reliable voice and data communications for both

mobile and fixed users in a tactical environment. The ACUS operates from the front-line maneuver
DoD IMT-2000 Assessment

C-2

battalions to the theater headquarters in the rear areas. This communication network is formed in two

parts; the MSE and the TRI-TAC system. The MSE system is deployed at corps-level units to

maneuver battalions and the TRI-TAC system is deployed at Echelon Above Corps (corps-level units

to higher headquarters). The system operates like a high capacity personal communications system

with rapidly transportable base stations. A three Division corps-size deployment could deploy up to

eighteen microwave links depending on the operational or exercise scenario.

From command and control traffic to intelligence imagery, logistics, medical, and morale and welfare

support, MSE and TRI-TAC provide the force commanders the ability to maintain effective control

over their forces. MSE and TRI-TAC are tactical systems for rapid deployment in the field. This is

because headquarters units, with their signature electronic emissions, are targeted for artillery and

missile attacks by the enemy. The ability to set up a link to higher headquarters and subordinate units

and then take down the link and move is key to the survivability of the headquarters and supports the

concept of maneuver warfare. The microwave radio equipment and antennas are transportable and

robust for field conditions. To maintain the operator’s capability to quickly establish a tactical

microwave link, continuous field training is required.

ACUS/MSE is planned for use by the US Joint Forces Command (USJFCOM) to support Joint Task

Force Civil Support (JTF-CS) in the event of a Weapons of Mass Destruction (WMD) incident. JTFCS is tasked to provide support to a Designated Lead Federal Agency in the conduct of consequence

management operations in response to a Chemical, Biological, Radiological, Nuclear and High Yield

Explosives (CBRNE) incident or accident in the Continental United States (CONUS), Alaska,

Hawaii, US territories and possessions.

Additionally, ACUS/MSE is used for other contingency operations within the US to include disaster

relief, national emergencies, and other DoD support requirements to civil authorities, as directed from

the National Command Authority.

C.1.2 Digital Wideband Transmission System

The Navy/Marine Corps DWTS provides a backbone digital communications capability, supporting

amphibious operations and ground combat operations. The system supports command, control, and

data transfer from the Marine Expeditionary Force (MEF) level down to the regimental level. The

AN/MRC-142 is the Marine Corps element of this radio system, providing the digital backbone

services (voice, video and data). This link is the only transmission media available to the Marine

Corps with sufficient bandwidth to carry large quantities of critical data such as maps, overlays,

intelligence pictures, and other data to the battlefield commanders. From command and control

traffic to intelligence imagery, logistics, medical, and morale and welfare support, DWTS provides
DoD IMT-2000 Assessment

C-3

the force commanders the ability to maintain effective control over their forces. DWTS is a tactical

systems designed to set up in the field quickly, similar to the Army’s ACUS. Headquarters units,

with their signature electronic emissions, are targeted for artillery and missile attacks by the enemy.

The ability to set up a link to higher headquarters and subordinate units and then take the link down

and move is key to the survivability of the headquarters and supports the concept of maneuver

warfare. The microwave radio equipment and antennas are transportable and robust for field

conditions. To maintain the operator’s capability to quickly establish a tactical microwave link,

continuous field training is required. The Navy ship-to-shore link of DWTS is the AN/SRC-57 radio.

This is essential for amphibious operations where most of the critical information flow is from the

ship to the landing forces. The anticipated service life of the AN/MRC-142 extends beyond the 2010

time frame.

DWTS is a MSE equivalent system planned for use by the USJFCOM to support JTF-CS in the event

of a WMD incident. JTF-CS is tasked to provide support to a designated Lead Federal Agency in the

conduct of consequence management operations in response to a CBRNE incident or accident in the

CONUS, Alaska, Hawaii, US and possessions (US&P).

Additionally, DWTS is used for other contingency operations within the US to include disaster relief,

national emergencies, and other DoD support requirements to civil authorities, as directed from the

National Command Authority.

C.2 TACTICAL RADIO RELAY SYSTEM DESCRIPTIONS

MSE. The MSE is a multi-band, tactical LOS radio system, more accurately described as a “systemof-systems,” because it is composed of several components, each of which are fully operational

systems. The individual components that make up the MSE are dependent upon several portions of

the radio frequency spectrum (e.g., 30-88 MHz, 225-400 MHz, 1350-1850 MHz, and

14.5-15.35 GHz). The inability of any of these components to operate successfully would result in

the failure of the overall system. One critical component of the MSE, the AN/GRC-226(V)2 radio,

operates in the 1755-1850 MHz frequency band. It is used to connect radio access units to the node

center switch of the network. Operational use plans call for 465 units per Army Corps, giving a total

of 2,325 units for five Corps. The AN/GRC-226(V)2 is a digital radio that can tune to any of 4000

available channels, spaced at 125 kHz, between 1350-1850 MHz; however, due to the allocation of

most of this band to other services, users rarely have access to spectrum outside of 1350-1390 MHz

and 1710-1850 MHz. The AN/GRC-226(V)2 requires a 50.125-MHz minimum frequency separation

between the site transmitter and receiver for a duplex link. The technical parameters of the AN/GRC226(V)2 used in the analysis are presented in Table C-1.
DoD IMT-2000 Assessment

C-4

Table C-1. AN/GRC-226 (V)2 Parameters (J/F 12/6102/2)

Frequency range 1350 – 1850 MHz

Transmit power 0.5 - 5 W

Emission Bandwidth (MHz)* 1.25 (-3dB), 3.5 (-20dB), 10.55 (-60dB)

Antenna gain 20 dBi (MB), 11 dBi (20-90 deg), 2 dBi (90-180 deg)

Antenna height 30 m

Receiver bandwidth (MHz)* 0.85 (-3dB), 1.6 (-20dB), 4.4 (-60dB)

Receiver noise figure 8 dB

Receiver sensitivity -93 dBm @ BER = 10E–5 (S/N = 14 dB)

Receiver noise power -107 dBm

Interfering signal threshold -113 dBm

Cable losses 2.4 dB (estimated)

Waveform 2M40F9W*, 256 – 2048 kb/s MSK *

2048 kb/s is the maximum bit rate.

MB – mainbeam

MSK – minimum shift keying

TRI-TAC. The TRI-TAC system uses the AN/GRC-103(v)3 TRR unit to provide connectivity to

Army Echelons Above Corps. There are over 600 of these radios in use by the Army and reserve

units throughout the US. With respect to the technical assessment addressed in this appendix, the

technical parameters of the AN/GRC-103(v)3 are similar to those of the AN/GRC-226. The results

of the interference assessment of the AN/GRC-226 is considered to be generally applicable to the

AN/GRC-103(v)3.

HCLOS. The High Capacity LOS (HCLOS) radio system is expected to eventually replace the

AN/GRC-226(V)2 radios in the MSE for the ACUS. The HCLOS radio, the AN/GRC-245(V),

operates in the 225-400 MHz and 1350-2690 MHz bands with increased spectral efficiency and

higher data rates compared to the current radio. The AN/GRC-245(V) requires a 50.125-MHz

minimum frequency separation between the site transmitter and receiver for a duplex link. The

technical parameters of the AN/GRC-245(V) used in the assessment are presented in Table C-2.

Table C-2. AN/GRC-245 (V) Parameters (J/F 12/7601)

Frequency range 1350 – 2690 MHz

Transmit power 31 mW - 1.6 W

Emission Bandwidth (MHz)* 2.0 (-3dB), 2.9 (-20dB), 7.2 (-60dB)

Antenna gain 23 dBi (mainbeam)

Antenna height 30 m

Receiver bandwidth (MHz)* 6.7 (-3dB), 8.1 (-20dB), 10.0 (-60dB)

Receiver noise figure 7 dB

Receiver sensitivity* -86 dBm @ 8192 Kb/s and BER = 10E-5

Receiver noise power* -99 dBm

Interfering signal threshold* -105 dBm

Cable losses 4 dB @ 1850 MHz

Waveform 2M50W1D*,320-8256 kb/s, 32 TCM, rate 4/5 code *

8256 kb/s is the maximum bit rate.

TCM – trellis coded modulation
DoD IMT-2000 Assessment

C-5

DWTS. The DWTS is a LOS tactical radio system providing point-to-point (shore based AN/MRC142), ship-to-ship (ship based AN/SRC-57) and ship-to-shore (AN/SRC-57 and AN/MRC-142 or the

Army AN/GRC-226) communications. The DWTS provides communications vital to the

Commander Joint Task Force (CJTF), Commander Amphibious Task Force (CATF), Commander

Landing Force (CLF), Amphibious Forces afloat, and US Forces ashore. The system provides afloat

and ashore commanders with entry into the Global Command and Control System – Maritime

(GCCS-M) to ensure common access to intelligence, mapping, order of battle, and logistics

information. The DWTS provides data transmissions for Battlegroup (BG) planning, video teleconferences, BG e-mail connectivity, Internet connectivity and intra-BG telephone connectivity.

DWTS provides tactical digital wideband transmissions for voice, video, and data to support landing

force command elements to include Marine regiment or Expeditionary Unit and higher and Army

brigade and higher. The DWTS consists of two components, the shore based USMC AN/MRC-142

and the ship based US Navy AN/SRC-57.

AN/MRC-142. The shore based component of the DWTS, the AN/MRC-142, typically uses the

frequency bands 1350-1390 MHz, 1432-1435 MHz, and 1710-1850 MHz. In addition, the AN/MRC142 ship-to-shore links have further frequency restrictions caused by ship-based interference to the

AN/SRC-57 located on ships. The AN/MRC-142 requires a 63-MHz minimum frequency separation

between the site transmitter and receiver for a duplex link. The technical parameters of the

AN/MRC-142 used in the evaluation are presented in Table C-3.

Table C-3. AN/MRC-142 Parameters (J/F 12/6461)

Frequency range 1350 – 1850 MHz

Transmit power 3.0 W

Emission Bandwidth (MHz) 0.4 (-3dB), 1.05 (-20dB), 3.15 (-60dB)

Antenna gain 20 dBi (mainbeam), 6.3 dBi (26 deg)

Antenna height 30 m

Receiver bandwidth (MHz) 0.8 (-3dB), 1.0 (-40 dB), 4.4 (-60 dB)

Receiver noise figure 8 dB

Receiver sensitivity -93 dBm BER = 10E-4

Receiver noise power -107 dBm

Interfering signal threshold -113 dBm

Waveform 610K0F7W, 576kb/s FSK

FSK – frequency shift keying

AN/SRC-57. The ship-based AN/SRC-57 uses an omnidirectional antenna to communicate with

other ships and shore-based radios. The AN/SRC-57 can tune over the 1350-1850 MHz frequency

band for operations in international waters. However, the AN/SRC-57 was granted stage four

spectrum certification to operate in the bands of 1350-1390 MHz and 1755-1850 MHz within the

US&P. The AN/SRC-57 can experience shipboard interference interactions that could eliminate

additional frequency bands. The AN/SRC-57 can receive interference from shipboard systems such

as the Target Acquisition System (TAS) MK 23 radar, AN/SPS-49 radar, and International Maritime
DoD IMT-2000 Assessment

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Satellite (INMARSAT) and can cause interference to Global Positioning System (GPS),

INMARSAT, and AN/SMQ-11 Weather Satellite receivers.

The AN/SRC-57 requires a 50-MHz minimum frequency separation between the site transmitter and

receiver for ship-to-ship duplex links; however, ship-to-shore links must conform to the 63 MHz

separation requirements of the AN/MRC-142. The technical parameters of the AN/SRC-57 used in

the assessment are presented in Table C-4.

Table C-4. AN/SRC-57 Parameters (J/F 12/7652)

Frequency range 1350 – 1850 MHz

Transmit power 5 – 250 W

Emission Bandwidth (MHz) 1.0 (-3dB), 3.0 (-20 dB), 8.0 (-60 dB)

Antenna gain 1.5 dBi Omni

Antenna height 30 m

Receiver bandwidth (MHz) 1.6 (-3 dB), 4.0 (-20 dB), 9.2 (-60 dB)

Receiver noise figure 7 dB

Receiver sensitivity -84 dBm BER = 10E-5

Receiver noise power -105 dBm

Interfering signal threshold -111 dBm

Waveform 2M85F7D, 144-2304 kb/s binary FSK

C.3 COST ISSUES

There are two major equipment types in this category, the Army’s MSE and TRI-TAC, and the

Navy/Marine Corps DWTS. Both of these systems rely on the 1755-1850 MHz band to provide the

high-end frequency component of their full-duplex channel pairs. Although both equipment sets tune

over an extended frequency range, loss of this particular band would significantly reduce the number

of radios which could be netted together during training exercises due to non availability of alternate

bands to provide the high-end frequency component of the duplex channel. The Army has already

encountered this problem with their MSE and TRI-TAC systems in Europe. To alleviate the

problem, they have begun the acquisition and fielding of a new generation of radio called High

Capacity Line of Sight (HCLOS) or AN/GRC-245. HCLOS tunes over an even wider range than

baseline MSE and TRI-TAC, and offers the potential to mitigate the IMT-2000 third-generartion

(3G) problem as well. Similar to the combat aircraft training systems, the HCLOS mitigation

strategy assumes that the wider tuning range will cover some new bands that can be used by the

Army to setup MSE and TRI-TAC radio links. If no such bands are provided this proposed solution

is not viable. DoD’s mitigation strategy for the Army’s MSE and TRI-TAC equipment calls for

accelerating the procurement of HCLOS considerably over the baseline program DoD currently has

in place. As per the cost reimbursement rules defined in NTIA’s Notice of Proposed Rulemaking

(NPRM), the difference in the accelerated budget requirements over and above the baseline

requirements are reimbursable and so are included in the cost estimate for IMT-2000. The same

MSE and TRI-TAC program plan would be implemented under either band segmentation option,
DoD IMT-2000 Assessment

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band sharing, or if access to the band was lost completely. The same plan would also be

implemented regardless of the 3G introduction date.

The DoD plan for mitigating the effect of the Navy/Marine Corps DWTS system on IMT-2000 is

slightly more complex than the strategy for the Army's MSE. The Navy/Marine Corps rely heavily

upon these links for point to point land communications and the ship to shore links. Therefore, each

option (band sharing, segmentation, band loss) must be viewed independently and with reference to

operational considerations and cost. The band sharing option would require the Marine Corps to

operate using fixed locations and antenna orientations or power constraints, all of which are

inconsistent with the Marine Corps operational doctrine for maneuver warfare. In the event of

segmentation or band loss, the Marine Corps envisions replacing the existing MRC-142 with either a

modified non-developmental item (NDI) (possibly a HCLOS-like) system or a new development

system based on the newly assigned spectrum. Note: Since HCLOS was never designed to work

with DWTS, it would require non-recurring integration effort. Tables C-5 and C-6 present

reimbursement cost data.

Table C-5. Mobile Subscriber Equipment (HCLOS) Reimbursement Cost (TY$M)

FY02 FY03 FY04 FY05 FY06 FY07 To Complete Total

HCLOS Acceleration 40.1 49.0 48.7 11.6 0.0 0.0 0.0 149.5

Table C-6. Digital Wideband Transmission System Reimbursement Cost (TY$M)

DWTS Band Segmentation Options Reimbursement Cost (TY$M)

FY02 FY03 FY04 FY05 FY06 FY07 To Complete Total

Marine Corps 9.9 5.1 50.6 53.6 65.6 65.6 270.0 520.4

Navy 4.0 5.0 1.5 0.5 0.5 0.5 7.0 19.0

Total 13.9 10.1 52.1 54.1 66.1 66.1 277.0 539.4

DWTS Band Vacation Option Reimbursement Cost (TY$M)

FY02 FY03 FY04 FY05 FY06 FY07 To Complete Total

Marine Corps 10.0 15.0 15.0 55.6 53.6 65.6 320.6 535.4

Navy 5.4 6.7 11.5 10.7 10.7 10.7 9.8 65.5

Total 15.4 21.7 26.5 66.3 64.3 76.3 330.4 600.9

DWTS Band Sharing Option Reimbursement Cost (TY$M)

FY02 FY03 FY04 FY05 FY06 FY07 To Complete Total

Marine Corps 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

Navy 5.4 6.7 11.5 10.7 10.7 10.7 7.0 62.7

Total 5.4 6.7 11.5 10.7 10.7 10.7 7.0 62.7
DoD IMT-2000 Assessment

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C.4 OPTION 1 – FULL BAND SHARING

C.4.1 Technical Assessment

The DoD TRR systems potential for sharing the 1755-1850 MHz frequency band with the IMT-2000

systems was investigated on a one-to-one basis. A distance separation required to protect each of

four radio relay systems from each of the four candidate IMT-2000 systems and each of the four

candidate IMT-2000 systems from the four radio relay systems was determined. The IMT-2000

mobiles and base stations (including main-beam and side-lobe antenna gains) were analyzed versus

the radio relay main-beam and side-lobe antenna gains. The ship-based DWTS uses an

omnidirectional antenna, and the DWTS was analyzed at the highest and lowest transmitter power

setting.

The technical parameters for the tactical radios (see the System Description section) were obtained

from the Spectrum Certification Applications and from data provided by the program manager for

each radio. The technical parameters for the IMT-2000 radios used in the sharing assessment are

presented in a previous section of this report. The interference threshold values of the IMT-2000

code division multiple access (CDMA) system receivers are referenced to the data rate of the CDMA

modulation. The interference threshold referenced to the receiver bandwidth would be increased by

the ratio of the receiver bandwidth to the data rate. The revised interference thresholds (It) are

presented in Table C-7.

Table C-7. CDMA-2000 Receiver Interference Thresholds

CDMA-2000 Narrowband (NB)

(1.25 MHz)

CDMA-2000 Wideband (WB)

(3.75 MHz)

Base Mobile Base Mobile

Interference

Threshold 1

-114.6 dBm -110.6 dBm -109.9 dBm -105.9 dBm

Interference

Threshold 2

-99.1 dBm -95.1 dBm -94.4 dBm -90.4 dBm

The interference thresholds for the DoD tactical radio receivers were based on the Recommendation

ITU-R F.1334, which limits the degradation due to interference in the fixed service receiver to 1 dB.

This value corresponds to an allowed interference-to-noise power ratio (I/N) of –6 dB. Also, for one

example, an additional, higher threshold was used, assuming a desired signal level of –75 dBm, and

an signal-to-interference plus noise ratio (S/(I+N)) of 14 dB.

The analysis was performed to identify the required distance separation to protect the TRR receivers

from the IMT-2000 transmitters and the IMT-2000 receivers from the TRR transmitters. The
DoD IMT-2000 Assessment

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required propagation loss was calculated using transmitter powers, transmitter and receiver antenna

gains, frequency-dependent rejection, and the receiver interference threshold as follows:

 LP = PT + GT + GR + LS – FDR – IT (C-1)

where:

LP = required propagation path loss to preclude interference (dB)

PT = output power of the source transmitter (dBm)

GT = source transmit antenna gain in the direction of the victim receiver (dBi)

GR = victim receive antenna gain in the direction of the source transmitter (dBi)

LS = transmitter and receiver line losses (dB)

FDR = frequency-dependent rejection (dB)

IT = receiver interference threshold (dBm).

The Spherical Earth Model (SEM) was used to determine the required distance separation to preclude

interference. The SEM is applicable to paths over a smooth, spherical, homogenous, and imperfectly

conducting earth. The dominant mode of propagation can be either LOS, diffraction, or tropospheric

forward-scatter. The SEM calculates the required distance separation based on the required

propagation loss, link frequency, and transmitter/receiver antenna heights.

The above assessment was used to evaluate the frequency separation versus distance separation

requirements for one sample case of the AN/GRC-226 and the CDMA WB (3.75 MHz). The

receiver selectivity and the transmitter emission spectrum were off-tuned, and the FDR was

determined for several values of frequency separation.

C.4.2 Results

The IMT-2000 to TRR distance separation requirements are presented in Table C-8, the TRR to IMT2000 (minimum interference threshold) distance requirements are presented in Table C-9, and the

TRR to IMT-2000 (more typical interference threshold) distance separation requirements are

presented in Table C-10.

For the minimum interference threshold case, the distance separation requirements between the TRR

and the IMT-2000 base stations would be approximately 92 km if random antenna orientations were

allowed for both systems. With the same interference threshold, the distance separation requirements

between the TRR and the IMT-2000 base stations would be approximately 55 km if side-lobe antenna

orientations were constrained for each system toward the other system (assumes low-power operation

for the AN/SRC-57).
DoD IMT-2000 Assessment

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With the minimum interference threshold, the distance separation requirements between the TRR and

the IMT-2000 mobiles would be approximately 38 km, if random antenna orientations were allowed

for the TRR. If TRR main-beam antenna orientations (assumes low-power operation for the

AN/SRC-57) were constrained away from areas of IMT-2000 operations and IMT-2000 mobiles

were restricted from some areas of operations, the distance separation requirements would be

approximately 23 km. The above distance separation requirements cannot be accommodated in many

areas of TRR operations in the US.

Table C-8. IMT-2000 to Tactical Radio Relay Distance Separation Requirements

Co-Channel Operation

Interference Path CDMA NB CDMA WB IS-136 GSM

Source Victim Distance (Km) Distance (Km) Distance (Km) Distance (Km)

IMT-2000 Base GRC-226 MB 87.1 78.1 91.9 91.1

IMT-2000 Base GRC-226 SL 63.9 60.7 65.5 65.2

IMT-2000 Base SL GRC-226 SL 52.3 49.0 53.9 53.7

IMT-2000 Mobile GRC-226 MB 22.5 19.8 23.8 23.6

IMT-2000 Mobile GRC-226 SL 11 9.2 11.9 11.8

IMT-2000 Base GRC-245 MB 75.2 74.7 75.5 75.5

IMT-2000 Base GRC-245 SL 56.8 56.5 57.0 57.0

IMT-2000 Base SL GRC-245 SL 45.0 44.6 45.1 45.1

IMT-2000 Mobile GRC-245 MB 18.8 18.5 19.0 19

IMT-2000 Mobile GRC-245 SL 7.4 7.2 7.5 7.5

IMT-2000 Base MRC-142 MB 85.5 75.7 91.9 91.1

IMT-2000 Base MRC-142 SL 63.4 59.8 65.5 65.2

IMT-2000 Base SL MRC-142 SL 51.8 48.0 53.9 53.7

IMT-2000 Mobile MRC-142 MB 22.0 19.0 23.8 23.6

IMT-2000 Mobile MRC-142 SL 10.7 8.7 11.9 11.8

 

IMT-2000 Base SRC-57 62.0 59.0 63.3 63.1

IMT-2000 Base SL SRC-57 50.3 47.2 51.7 51.5

IMT-2000 Mobile SRC-57 10 8.4 10.6 10.5
DoD IMT-2000 Assessment

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Table C-9. Tactical Radio Relay to IMT-2000 Distance Separation Requirements

Co-Channel Operation

Minimum Interference Threshold 

Interference Path CDMA NB CDMA WB IS-136 GSM

Source Victim* Distance (Km) Distance (Km) Distance (Km) Distance (Km)

GRC-226 MB IMT-2000 Base 82 75.4 85.0 84.2

GRC-226 SL IMT-2000 Base 62.2 59.6 63.2 62.9

GRC-226 SL IMT-2000 Base SL 50.5 47.9 51.6 51.3

GRC-226 MB IMT-2000 Mobile 34 31.5 35.0 34.7

GRC-226 SL IMT-2000 Mobile 19.5 17.5 20.4 20.2

GRC-245 MB IMT-2000 Base 73.7 71.9 75.2 74.1

GRC-245 SL IMT-2000 Base 55.4 53.5 56.1 55.9

GRC-245 SL IMT-2000 Base SL 43.5 41.6 44.3 44.1

GRC-245 MB IMT-2000 Mobile 30.0 28.3 30.7 30.5

GRC-245 SL IMT-2000 Mobile 14.5 13.3 15.0 14.9

MRC-142 MB IMT-2000 Base 81.3 73.6 91.4 90.5

MRC-142 SL IMT-2000 Base 61.9 58 65.6 65

MRC-142 SL IMT-2000 Base SL 50.2 46.2 54.1 53.5

MRC-142 MB IMT-2000 Mobile 33.7 29.9 37.4 36.8

MRC-142 SL IMT-2000 Mobile 19.4 16.3 22.5 21.9

 

SRC-57 HP IMT-2000 Base 79.8 74.0 83.5 82.7

SRC-57 LP IMT-2000 Base 62.2 59.3 63.6 63.3

SRC-57 HP IMT-2000 Base SL 65.7 62.9 67.0 66.8

SRC-57 LP IMT-2000 Base SL 50.6 47.6 52.0 51.7

SRC-57 HP IMT-2000 Mobile 33.2 30.3 34.5 34.2

SRC-57 LP IMT-2000 Mobile 19.6 17.3 20.7 20.5

*Desired signal at sensitivity, I/N = - 6 dB
DoD IMT-2000 Assessment

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Table C-10. Tactical Radio Relay to IMT-2000 Distance Separation Requirements

Co-Channel Operation

For one example interaction, the distance separation requirements were also determined for the case

of a TRR link with a typical received signal level. The example uses CDMA WB (3.75 MHz)

interference to an AN/GRC-226 receiver. The AN/GRC-226 link with an elevated site location and

favorable weather parameters could receive a faded desired signal level of -75 dBm with a

corresponding interference threshold of -89 dBm, for an S/(I+N) = 14 dB. The required distance

separation values for this example are presented in Table C-11.

If an interference threshold for a typical received signal level (approximately 10 dB above receiver

sensitivity for the IMT-2000 or -75 dBm for the AN/GRC-226) is used, the separation requirements

are 68 km and 40 km for random antenna orientations (mainbeam) and sidelobe antenna orientations,

respectively. These less conservative separation distances would still be difficult to implement at

most TRR operations areas.

Typical Interference Threshold

Interference Path CDMA NB CDMA WB IS-136 GSM

Source Victim* Distance (Km) Distance (Km) Distance (Km) Distance (Km)

GRC-226 MB IMT-2000 Base 64.3 61.8 65.4 65.1

GRC-226 SL IMT-2000 Base 48.2 45.6 49.3 49.0

GRC-226 SL IMT-2000 Base SL 36.2 33.6 37.4 37.1

GRC-226 MB IMT-2000 Mobile 21.3 19.2 22.2 22.0

GRC-226 SL IMT-2000 Mobile 10.2 8.9 10.8 10.7

GRC-245 MB IMT-2000 Base 60.3 58.4 61.0 60.8

GRC-245 SL IMT-2000 Base 41.2 39.3 42.0 41.8

GRC-245 SL IMT-2000 Base SL 29.3 27.4 30.0 29.8

GRC-245 MB IMT-2000 Mobile 18.1 16.7 18.6 18.5

GRC-245 SL IMT-2000 Mobile 7.0 6.2 7.3 7.2

MRC-142 MB IMT-2000 Base 64.1 60.2 67.8 67.2

MRC-142 SL IMT-2000 Base 47.9 43.9 51.8 51.2

MRC-142 SL IMT-2000 Base SL 36.0 31.9 39.9 39.3

MRC-142 MB IMT-2000 Mobile 21.1 18.0 24.4 23.8

MRC-142 SL IMT-2000 Mobile 10.1 8.1 12.3 11.9

SRC-57 HP IMT-2000 Base 63.6 60.7 64.9 64.6

SRC-57 LP IMT-2000 Base 48.3 45.3 49.7 49.4

SRC-57 HP IMT-2000 Base SL 52.0 48.9 53.3 53.0

SRC-57 LP IMT-2000 Base SL 36.3 33.3 37.7 37.5

SRC-57 HP IMT-2000 Mobile 20.7 18.3 21.8 21.6

SRC-57 LP IMT-2000 Mobile 10.3 8.7 11.0 10.9

*Desired Signal 10 dB above sensitivity and BER = 10E-3
DoD IMT-2000 Assessment

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Table C-11. CDMA-2000 NB (1.25 MHz) to AN/GRC-226

Co-Channel Operation

The frequency separation verses distance separation requirements for one sample case of the

AN/GRC-226 and the CDMA WB (3.75 MHz) are presented in Table C-12. The frequency

separation was limited to 5 MHz because data was not available on the IMT-2000 systems that are

under development. These preliminary calculations indicate that separation distances of 34.5 km are

required for one channel separation (5MHz) between the AN/GRC-226 and the CDMA WB

(3.75 MHz) base station.

Table C-12. Frequency Vs. Distance Separation Requirements for the

AN/GRC-226 and the CDMA-2000 WB (3.75 MHz)

Interference Path Off-tuning Separation

Distance

Source Victim MHz Km

AN/GRC-226 MB CDMA WB Base 0 75.3

1.0 75.3

2.0 70.6

3.0 58.3

4.0 45.6

5.0 34.5

CDMA WB Base AN/GRC-226 MB 0 78.1

1.0 75.3

2.0 69.9

3.0 55.7

4.0 20.5

5.0 16.4

C.4.3 Operational Impact

C.4.3.1 Mobile Subscriber Equipment

For the 2003 time frame, the Army must continue to operate MSE and TRI-TAC in the

1755-1850 MHz band for battlefield training. Accommodating 3G systems in the 1755-1850 MHz

Interference Path Source Transmitter Data Victim Receiver Data FDR

Path 

Loss Distance

Source Victim Power Antenna TX Cable Int Thresh Antenna RX Cable SEM

dBm dBi dB dBm dBi dB dB dB Km

CDMA NB Base GRC-226 MB 40 15 1 -89 20 2.4 1.8 158.8 58.6

CDMA NB Base GRC-226 SL 40 15 1 -89 2 2.4 1.8 140.8 42.2

CDMA NB Base SL GRC-226 SL 40 2 1 -89 2 2.4 1.8 127.8 30.3

CDMA NB Mobile GRC-226 MB 20 0 0 -89 20 2.4 1.8 124.8 8.2

CDMA NB Mobile GRC-226 SL 20 0 0 -89 2 2.4 1.8 106.8 3.0
DoD IMT-2000 Assessment

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band will compound the difficulties the Army experiences today. Restricting transmitter/receiver

locations and antenna-pointing directions will limit realistic training of units and will limit the

commanders’ ability to realistically deploy signal assets. Not setting up links in exercise scenario

dependent locations, but instead setting them up in pre-planned, pre-coordinated sites exercise after

exercise, reduces the microwave operator’s combat skills. The learning curve for setting up the links

in actual deployment situations will be steeper and longer because of the lack of realistic field

exercise training. The time required to get effective command and control established, especially in

the information intensive battleground today, can be a deciding combat factor. Because of this,

realistic training operations for microwave systems must continue.

US Army Guard and Reserve units are deploying at a greater pace, and keeping their training current

is vital. Guard and Reserve component units with ACUS/MSE and TRI-TAC systems may be

severely restricted in training opportunities because of their proximity to IMT-2000 base

stations/mobile phone concentrations. There are 10 Army National Guard Division Signal Battalions

with MSE AND TRI-TAC located throughout the US and a number of Army Reserve Signal units

(companies, battalions, brigades, commands) with ACUS/TRI-TAC systems using the AN/GRC-103

(V)4 radio. Army Reserve Air Defense units in the also use the AN/GRC-103 (V)4 radio. If these

units are restricted from training operations at home locations, then the units must deploy to the

nearest training area, thereby imposing significant cost on training that can be accomplished today

with relatively small investment.

If 3G is accommodated in this frequency band, and mitigation techniques are imposed on the Army

ACUS, the installation Frequency Managers would need to coordinate with the IMT-2000 system

operators prior to conducting training exercises to determine acceptable frequencies for use. At bases

near population centers, this will be difficult because of the large separation distances required to

preclude interference under co-frequency operation and because of how ACUS is deployed. The

frequency managers at Ft Hood, TX, Ft Bragg, NC, and the National Training Center at Ft Irwin, CA,

are already facing crowded frequency space and further sharing restrictions will make any large-scale

exercises unworkable. Restricting the size of exercises could reduce the radiation problem but could

preclude full scale training exercises. If IMT-2000 systems are deployed in significant numbers

around the base, the only choice is to reduce the size and scope of training exercises—directly

affecting military readiness.

For 2006 and 2010, the operational impact to US forces, if IMT-2000 systems begin operation in the

1755-1850 MHz band, are the same as 2003, unless access to additional spectrum in bands up to

2690 MHz is provided on a primary basis with equivalent regulatory protection. As HCLOS radios

replace the current generation of MSE and TRI-TAC equipment, additional flexibility in frequency

selection could reduce, but not eliminate, the impact resulting from loss of the 1755-1850 MHz band.
DoD IMT-2000 Assessment

C-15

C.4.3.2 Digital Wideband Transmission System

The option for full band sharing is extremely difficult, as described previously in the section on

ACUS/MSE. The Navy/Marine Corps depend on the DWTS for information transfer between ships

and troops ashore as well as dissemination throughout the battlefield. There are no replacement

radios planned for the DWTS, so continued access to the 1755-1850 MHz band is crucial to

amphibious operations training. Marine Corps training/warfare doctrine is based on maneuver

warfare. The ability of the Fleet Marine Force and its commanders to effectively train troops would

be severely degraded if restrictions on flexibility were imposed to allow 3G systems to operate in the

same band as DWTS.

By restricting the location of transmitters and receivers, restricting the direction in which antennas

can be pointed, limiting link lengths, or limiting transmitter power levels, the Marine Corps capability

for training maneuver warfare and command and control is greatly reduced. The whole premise

behind maneuver warfare is rapid movement and quick-strike engagement of the enemy. The

communications network must remain as mobile as the rest of the command and control elements.

The Marine Corps would immediately lose the capability to train Marines as they would fight.

DWTS also serves as the link between Navy amphibious support ships and the Marine Corps troop

ashore. Restrictions on transmitter power, antenna pointing angles, link lengths, and other factors

would reduce or eliminate the utility of this vital link. Ship movement requires broad beamwidth

antennas for the shore system so that communications can be maintained while the ship retains

freedom of movement for self-protection.

Limiting the size of exercises severely restricts the utility of training activities. If the Marine Corps

could no longer stage MEF/division level exercises, it would lose the ability to properly train its

troops and also lose the capability to rehearse for deployments. This would reduce the readiness of

our warfighters by increasing the time required to establish critical command and control links.

Restricting training to certain specified ranges would also severely impact operations. This will

require large troop movements to other training locations at a significant price in both cost and lost

time.

This especially impacts the Reserve units, as they would no longer be able to participate in local

training but would have to travel to specified training locations or ranges. Given the proximity of

Camp Pendleton to San Diego and other populous areas in Southern California, the entire base may

become off limits to large-scale training operations. Training at Yuma, AZ, may be curtailed as well

because of its location. Training at Quantico would also be in jeopardy because of its proximity to
DoD IMT-2000 Assessment

C-16

Northern Virginia and Washington, DC. Before long, training at Camp Lejeune would likely meet a

similar fate.

As stated previously, band sharing is not an option for the Marine Corps. There is no planned

replacement for the AN/MRC-142 prior to a Joint Tactical Radio System (JTRS) compliant

replacement, therefore any implementation of band sharing prior to 2010 results in the inability of

DWTS to support the way the Navy/Marine Corps trains and fights.

C.5 OPTION 2 – BAND SEGMENTATION/PARTIAL BAND SHARING

C.5.1 1755-1805 MHz Retained

The first band segmentation option would divide the 1755-1850 MHz band into two segments with

3G in 1710-1755 MHz and 1805-1855 MHz, and TRR in the 1755-1805 MHz band. This

segmentation plan would eliminate the 1805-1850 MHz band at all DoD TRR sites and possibly

eliminate 1710-1755 MHz at the 16 sites at which Federal systems are to be protected indefinitely as

specified in the Omnibus Budget Reconciliation Act of 1993 (OBRA-93). The TRR are currently

allocated the 1350-1390 and 1755-1850 MHz bands in CONUS and will receive protection

indefinitely in the 1432-1435 and 1710-1755 MHz bands at specific sites. The TRR is currently

allocated between 135 and 183 MHz of spectrum depending on the location. The Army can require

access to all the spectrum in the two 1350-1390 and 1755-1850 MHz sub-bands in order to satisfy

data requirements at the Corps and Division level. The US Marine Corps (USMC) has similar

spectrum requirements to support Marine Expeditionary Unit exercises and a requirement for

shipboard-compatible frequencies for ship-to-shore links. The spectrum lost in this option would

constitute 33% to 49% of the frequencies in the 1350-1850 MHz band used for the higher data rate

TRR communications networks. In addition, TRR duplex link frequency assignments would not be

possible at sites without access to 1350-1435 MHz frequencies because of the requirement for a

minimum of 50.125-63 MHz frequency separation between transmit and receive frequencies.

Sufficient band separation between transmit and receive frequencies is required by TRR systems for

acceptable operation.

2003 Time Frame. Any significant loss of access to spectrum in the band 1755-1850 MHz will have

unacceptable operational impact on radio relay operations.

2006 Time Frame. The IMT-2000 system is estimated at a 50% development level in urban areas

and 30% level in suburban areas. The development along interstate highways is expected to be in the

same range. The two sub-bands 1710-1755 and 1805-1850 MHz could be unavailable for TRR use at

this time frame. As a result, spectrum would not be available to support the number of TRR
DoD IMT-2000 Assessment

C-17

communications links required in large exercises. Any significant loss of access to spectrum in the

band 1755-1850 MHz will have unacceptable operational impact on radio relay operations.

The loss of access to the 1710-1755 and 1805-1850 MHz bands in 2006 would reduce the spectrum

to support TRR communications network by 33% to 49%. This loss of spectrum would have a

corresponding impact on the number of communications links available to support large exercises.

The impact between the TRR and the IMT-2000 systems at the band edges is addressed by a

frequency-distance separation analysis. The estimates for the IMT-2000 network in 2006 are for a

50% development in urban areas and along major interstate highways. At some TRR sites, the 1755-

1805 MHz band available for the TRR would have increasing power densities at the band edges from

the 3G transmitters in the surrounding bands. The frequency-distance separation requirement to

preclude interference was determined for both the TRR and the IMT-2000. The frequency-distance

separation requirements for CDMA-WB (spread spectrum) interference to the TRR is provided in

Figure C-1, and requirements for GSM (time division multiple access (TDMA)) interference to the

TRR is provided in Figure C-2. TRR interference to CDMA-WB is identified in Figure C-3, and

TRR interference to GSM is identified in Figure C-4.

0

10

20

30

40

50

60

70

80

90

0123456789

Off Tuned (MHz)

Distance Separation (km)

AN/GRC-245

AN/GRC-226

AN/MRC-142

AN/SRC-57

Figure C-1. Frequency-Distance Separation for CDMA-WB to TRR
DoD IMT-2000 Assessment

C-18

0

10

20

30

40

50

60

70

80

90

100

012345678

Off Tuned (MHz)

Distance Separation (km)

AN/GRC-245

AN/GRC-226

AN/MRC-142

AN/SRC-57

Figure C-2. Frequency-Distance Separation for IMT-2000 GSM to TRR

0

10

20

30

40

50

60

70

80

01234567

Off Tuned (MHz)

Distance Separation (km)

AN/GRC-226

AN/GRC-245

AN/MRC-142

AN/SRC-57

Figure C-3. Frequency-Distance Separation for TRR to CDMA-WB
DoD IMT-2000 Assessment

C-19

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

100

0123456

O ff Tuned (M Hz)

Distance Separation (km)

AN /G RC -226

AN /G RC -245

AN /M RC -142

AN /SR C -57

Figure C-4. Frequency-Distance Separation for TRR to GSM

The frequency-distance separation requirements in Figure C-1 to C-4 are for mainbeam antenna

interactions for both the TRR and the IMT-2000 radios. The data indicates that the TRR and the

IMT-2000 channel assignments at the edges of the 1755-1805 MHz would have to be controlled to

avoid interference impact to the TRR and an additional loss of spectrum. For example in Figure C-1,

the AN/GRC-226, AN/MRC-142 and AN/SRC-57 radios require approximately 30 km of separation

with CDMA-WB base stations for frequency assignments separated by 3.75 MHz (approximately the

band edge channel frequency separation) to provide compatible operations. However, the AN/GRC245 would require 70 km of separation for band edge channels to obtain compatible operations and

would have to increase the frequency separation to 6.25 MHz off tuned (approximately two channels

of separation) to obtain the 30 km distance separation. The interference from the TRR transmitters to

the IMT-2000 receivers in Figures C-3 and C-4 does not indicate a large difference in the separation

requirement between the four TRR transmitters. In urban areas, channels on the band edges could be

eliminated for TRR use if the AN/GRC-245 is assigned to the channels at the band edges.

2010 Time Frame. In the 2010 time frame, the IMT-2000 development level would be 100%, and

only 1755-1805 MHz frequencies would be available for the TRR. The spectrum lost in this option

would constitute 33% to 49% of the frequencies used for the higher data rate TRR communications

networks. The AN/GRC-245 could experience the loss of one additional 2.5 MHz channel at each

edge of the 1755-1805 MHz band at sites with high IMT-2000 traffic. In addition, TRR duplex link

frequency assignments would not be possible at sites without access to 1350-1435 MHz frequencies
DoD IMT-2000 Assessment

C-20

because of the requirement for a minimum of 50.125-63 MHz frequency separation between transmit

and receive frequencies.

C.5.2 Phased Segmentation to 1790-1850 MHz Retained

This band segmentation proposal would locate IMT-2000 in 1710-1790 MHz and TRR in

1790-1850 MHz. The spectrum lost in this option would constitute 26% to 44% of the frequencies in

the 1350-1850 MHz band used for higher data rate tactical radio relay. The technical assessment is

the same as in subsection C.5.1.

2003 Time Frame. Any significant loss of access to spectrum in the band 1755-1850 MHz will have

unacceptable operational impact on radio relay operations.

2006 and 2010 Time Frame. This band segmentation proposal would locate IMT-2000 in

1710-1790 MHz and TRR in 1790-1850 MHz. The IMT-2000 frequencies are not expected to be

available for TRR use in this time frame. The spectrum lost in this option would constitute 26% to

44% of the frequencies used for higher data rate tactical radio relay. The AN/GRC-245 could

experience the loss of one additional 2.5 MHz channel at each edge of the 1790-1850 MHz band at

sites with high IMT-2000 traffic. A limited number of duplex links would be available for the

AN/GRC-226, AN/GRC-245 and AN/SRC-57 radios using only the 1790-1850 MHz band. The

AN/MRC-142 radios could not obtain frequency assignments using only the 1790-1850 MHz band

because of the minimum 63 MHz frequency separation between the receiver and the transmitter on

duplex links.

C.5.3 Operational Impact

C.5.3.1 Mobile Subscriber Equipment

By 2003, any reduction in available spectrum would further reduce the size and scope of training

exercises in training areas where frequency space is already at a premium. Fielding of HCLOS radios

would not be sufficient to provide any significant relief in this time frame. Inputs to Army training

would be similar to those described in Option 1, around large training areas; however, the impacts to

Reserve and National Guard activities may be minimal if access in the remaining government

spectrum is maintained.

For the 2006 time frame, some impact to training is still expected; however, fielding of HCLOS

radios could improve the situation if access to frequencies up to 2690 MHz is provided on a primary

basis with equivalent regulatory protection. By the 2010 time frame, HCLOS fielding should have
DoD IMT-2000 Assessment

C-21

replaced current generation radios and if access to frequencies up to 2690 MHz is provided,

operational impacts to the Army ACUS will be minimal.

C.5.3.2 Digital Wideband Tactical System

This phased-segmentation scenario would not support the amphibious and general battlefield training

requirements because of the inherent limitations as specified in Option 1. The 50 MHz of continuous

frequency allocation listed in both scenarios does not allow for the requisite frequency separations

needed for collocated transmit and receive operation, and access to other portions of the DWTS

tuning range is already severely restricted. This would be true until a replacement radio could be

developed and fielded in significant numbers, which could not be accomplished until at least the 2010

time frame.

C.6 OPTION 3 – PARTIAL BAND SEGMENTATION/COMBINATION WITH

2025-2110, 2200-2290, AND 2500-2690 MHZ BANDS

C.6.1 Technical Assessment

The first band segmentation option would divide the 1755-1850 MHz band into two segments with

IMT-2000 in 1710-1755 MHz and 1805-1855 MHz, and TRR in the 1755-1805 MHz band. This

segmentation plan would eliminate the 1805-1850 MHz band at all TRR sites and eliminate

1710-1755 MHz at the 16 sites at which Federal systems are to be protected indefinitely as specified

in OBRA-93. The TRR are currently allocated the 1350-1390 and 1755-1850 MHz bands in CONUS

and will receive protection indefinitely in the 1432-1435 and 1710-1755 MHz bands at specific sites.

The TRR is currently allocated between 135 and 183 MHz of spectrum depending on the location.

The spectrum lost in this option would constitute 33% to 49% of the frequencies in the

1350-1850 MHz band used for the higher data rate TRR communications networks. In addition, TRR

duplex link frequency assignments would not be possible at sites without access to 1350-1435 MHz

frequencies because of the requirement for a minimum of 50.125-63 MHz frequency separation

between transmit and receive frequencies.

The second band segmentation proposed would locate IMT-2000 in 1710-1790 MHz and TRR in

1790-1850 MHz. The spectrum lost in this option would constitute 26% to 45% of the frequencies

used for higher data rate tactical radio relay.

The spectrum lost to the TRR through one of the partial band segmentation options (between 45 and

90 MHz) could possibly be replaced by spectrum above 2000 MHz if the existing TRR are replaced
DoD IMT-2000 Assessment

C-22

by radios operating at frequencies up to 2690 MHz. The 2025-2110, 2200-2290, 2500-2690 MHz

bands are evaluated for compatibility between the existing users of the band and the TRR.

2003 Time Frame. Any significant loss of access to spectrum in the band 1755-1850 MHz will have

unacceptable operational impact on radio relay operations.

2006 Time Frame. The IMT-2000 system is estimated at a 50% development level by in urban areas

and 30% level in suburban areas. The development along interstate highways is expected to be in the

same range. The IMT-2000 frequencies are not expected to be available for TRR use in this time

frame. The new TRR operating at frequencies above 2000 MHz are not expected to be available in

significant numbers by 2006, which would allow for the use of frequencies above 2000 MHz. As a

result, spectrum would not be available to support the number of TRR communications links required

in large exercises.

The loss of access to the 1710-1755 and 1805-1850 MHz bands in 2006 would reduce the spectrum

to support TRR communications network by 33% to 49%. The 1710-1790 MHz spectrum lost in the

second option would eliminate 26% to 45% of the frequencies used for higher data rate tactical radio

relay. This loss of spectrum would have a corresponding impact on the number of communications

links available to support large exercises.

The development and fielding of new TRR operating at frequencies above 2000 MHz would not be

possible before 2006. The Army has developed and received the initial procurement of the AN/GRC245 radios that can operate from 1350-2690 MHz. The AN/GRC-245 is not expected to be procured

in sufficient quantities to replace the AN/GRC-226 until near 2008. The USMC and the Navy have

recently fielded the AN/MRC-142 and AN/SRC-57 DWTS radios. A replacement DWTS radio with

an extended frequency range to 2690 MHz is not in development and the procurement of new radios

(if technically feasible) would extend beyond the 2006 time frame.

2010 Time Frame. In the 2010 time frame the IMT-2000 development would be complete and only

the 1350-1390 and 1755-1805 MHz frequency bands or the 1350-1390 and 1790-1850 MHz

frequency bands would be available for TRR use. The new TRR operating at frequencies above

2 GHz could be available by 2010. If sufficient spectrum is available for operations in the higher

bands, the communications requirements for large exercises could be supported. The AN/GRC-245

could experience the loss of one additional 2.5 MHz channel at each edge of the 1755-1805 MHz

band at sites with high IMT-2000 traffic.

The frequency bands above 2000 MHz available for DoD operations were investigated for suitability

for TRR operations. This investigation is discussed below.
DoD IMT-2000 Assessment

C-23

C.6.1.1 2025-2110 MHz Band

The 2025-2110 MHz band is used by the non-government fixed and mobile service, specifically

Electronic News Gathering (ENG) systems, by space research, by space operations (earth to space)

and Earth exploration-satellite services. The band would have to be allocated with equivalent

regulatory protection for government fixed and mobile services. The above incumbent systems in the

band were analyzed for compatibility with the TRR.

C.6.1.1.1 Electronic News Gathering

The ENG systems are used for on-location coverage of news events or live-action video during sports

and entertainment events. The transportable ENG, used by most local television stations for onlocation coverage, are generally mounted in vans and operate in a stationary mode transmitting video

to a fixed receive site. The total number of 2 GHz ENG systems in the US exceeds 4000. The

parameters of a typical ENG system are provided in Table C-13.1, 2

Table C-13. Parameters of a Typical Electronic News Gathering System

Frequency range 1990-2110 MHz

Transmit power 12 W

Channel Bandwidth (MHz) 17.0

Antenna gain 22 dBi (mainbeam), 2 dBi (sidelobe)

Antenna height 15 m (Transportable), 30 m (Fixed Receive)

Receiver bandwidth (MHz) 17.0 (-3dB)

Receiver noise figure 3 dB

Receiver sensitivity NA

Receiver noise power -99 dBm

Interfering signal threshold -108 dBm

Cable losses 2 dB

The interference power from the TRR to the ENG receiver was calculated using the standard received

power equation. The distance separation required to reduce the TRR power to a level below the ENG

interference threshold was calculated and provided in Table C-14. The reverse (ENG to TRR)

interference interactions were calculated and are provided in Table C-15.

 

1

 W. Horne, Characteristics and Model of Electronic News Gathering Systems Operating in the 1990-2110 MHz

Band, USTG 7-1/101, Greenbelt, MD: GSFC, 10 September 1993.

2

 Lloyd Apirian, et al., EMC and Personnel Exposure Analysis of Proposed Backup GOES Earth Station, JSC-CR97-035, Annapolis, MD: DoD JSC, October 1997.
DoD IMT-2000 Assessment

C-24

Table C-14. Interference Calculations TRR Transmitter to Electronic News Gathering (ENG) Receiver

2025-2110 MHz Band

Interference Path Source Transmitter Data Victim Receiver Data FDR

Path 

Loss Distance

Source Victim TX Power TX Antenna TX Cable** Inter Threshold*** RX Antenna* RX Cable SEM

dBm dBi dB dBm dBi dB dB dB Km

GRC-245 MB ENG Mainbeam 32 25 4 -108 22 2 0 181.0 75.2

GRC-245 MB ENG Sidelobe 32 25 4 -108 2 2 0 161.0 56.0

GRC-245 SL ENG Sidelobe 32 2 4 -108 2 2 0 138.0 37.3

*ENG receive station sidelobe gain is 2 dBi, receive station antenna height is 30 meters

** Cable loss from J/F 12 for GRC-245

***Desired signal at sensitivity, I/N = - 9 dB

Table C-15. Interference Calculations For Transportable Electronic News Gathering (ENG) to TRR Receiver

2025-2110 MHz Band

Interference Path Source Transmitter Data Victim Receiver Data FDR

Path 

Loss Distance

Source Victim TX Power TX Antenna* TX Cable Inter Threshold*** RX Antenna RX Cable** SEM

dBm dBi dB dBm dBi dB dB dB Km

ENG Mainbeam GRC-245 MB 40.8 22 2 -105 25 4 3.4 183.4 71.1

ENG Sidelobe GRC-245 MB 40.8 2 2 -105 25 4 3.4 163.4 50.2

ENG Sidelobe GRC-245 SL 40.8 2 2 -105 2 4 3.4 140.4 31.9

*ENG transmit station sidelobe gain is 2 dBi, transmit station antenna height is 15 meters

** Cable loss from J/F 12 for GRC-245

***Desired signal at sensitivity, I/N = - 6 dB

The distance separation requirement of 75.2 km between the TRR and the ENG fixed receive site

would be difficult to accomplish. The ENG receive sites are typically in urban areas, but many TRR

sites are within 75.2 km of urban areas. The distance separation requirements of 71.1 km between

the transportable ENG transmitter and the TRR would be more difficult to meet because the

transportable ENG range can extend into rural areas. Because of the distance separation requirements

to avoid interference and the large number of ENG systems, band sharing would not be possible

between the TRR and the ENG.

C.6.1.1.2 Space Ground Link Subsystem (SGLS) Uplink

The SGLS uplink operating in the 2025-2110 MHz band is assumed to have parameters that are the

same as the 1755-1850 MHz uplink. The parameters of the SGLS uplink have been provided in the

previous section. The analysis calculated the interference power from the SGLS transmitter to the

TRR using the standard received power equation. Green shading identifies the regions on the figures

where the SGLS interference exceeds the interference threshold of the TRR receiver.
DoD IMT-2000 Assessment

C-25

The plots for the New Hampshire Station (NHS), the Colorado Tracking Station (CTS), the Eastern

Vehicle Checkout Facility (EVCF) and the Onizuka Air Station (OAS) SGLS sites are provided in

Figures C-5 to C-8, respectively.

Figure C-5. Plot of NHS SGLS Interference to TRR Receivers
DoD IMT-2000 Assessment

C-26

Figure C-6. Plot of CTS SGLS Interference to TRR Receivers
DoD IMT-2000 Assessment

C-27

Figure C-7. Plot of EVCF SGLS Interference to TRR Receivers
DoD IMT-2000 Assessment

C-28

Figure C-8. Plot of OAS SGLS Interference to TRR Receivers

The analysis of the SGLS uplink interference to the TRR was based on the maximum transmit power

and a 3-degree elevation angle for the antenna at each SGLS site. This situation represented the

worst case interference from the SGLS transmitter to the TRR receiver. The TRR sites within the

green interference areas have a potential to receive interference during some SGLS operations for cochannel frequency assignments. The SGLS also uses transportable terminals, which can operate, at

any location in the US to provide additional coverage during launches, early orbit operations,

anomaly resolution, and critical orbit insertion maneuvers. The parameters of the transportable SGLS

terminals are similar to the parameters of the fixed SGLS systems and comparable interference

contours would be generated about the temporary SGLS location. The distance separation

requirements between the transportable SGLS (with the parameters of the EVCF earth terminal) and

the TRR would vary between 216 km and 59 km depending on the orientation of the SGLS and TRR

antennas as provided in Table C-16.
DoD IMT-2000 Assessment

C-29

Coordination between SGLS and TRR frequency managers could allow some frequencies to become

available for the TRR within the contour regions. However, TRR frequency usage in this band would

be subjected to positive control requiring possible shut down during SGLS emergencies. This level

of control would be difficult to accomplish during large-scale exercises.

C.6.1.1.3 Space Research

The 2025-2110 MHz band is also used for earth-to-space transmissions by other government space

research earth stations at Corpus Christi, TX; Fairbanks, AK; Goldstone, CA; Greenbelt, MD; Kauai,

HI; Merritt Is., FL; Roseman, NC and Wallops Is., MD. The Geostationary Operational

Environmental Satellite (GOES) earth stations uses the 2025-2035 MHz band at Wallops Is. for

tracking, telemetry and telecommand. The distance separation requirements between the GOES earth

terminal (parameters obtained from reference 2) and the TRR is provided in Table C-17.

 Table C-16. Interference Calculations for SGLS Transmitter to Tactical Radio Relay Receiver

2025-2110 MHz

Interference Path Source Transmitter Data Victim Receiver Data FDR

Path 

Loss Distance

Source Victim TX Power TX Antenna TX Cable Inter Threshold RX Antenna RX Cable**** SEM

dBm dBi dB dBm dBi dB dB dB Km

SGLS* GRC-245 MB 63.5 12 0 -105 23 4 0 199.5 134

SGLS* GRC-245 SL 63.5 12 0 -105 2 4 0 178.5 59

SGLS** GRC-245 SL 63.5 16 0 -105 2 4 0 182.5 63

SGLS*** GRC-245 MB 63.5 23 0 -105 23 4 0 210.5 216

*SGLS antenna diameter is 7 m, antenna height is 10 m, antenna gain is 12 dBi for a 10 degree antenna elevation angle

**SGLS antenna gain is 16 dBi for a 5 degree antenna elevation angle

***SGLS antenna gain is 23 dBi for a 3 degree antenna elevation angle

  Cable loss from J/F 12 for GRC-245

 Table C-17. Interference Calculations for GOES Transmitter to Tactical Radio Relay Receiver

2025-2035 MHz

Interference Path Source Transmitter Data Victim Receiver Data FDR

Path 

Loss Distance

Source Victim TX Power TX Antenna TX Cable Inter Threshold RX Antenna RX Cable** * SEM

dBm dBi dB dBm dBi dB dB dB Km

GOES* GRC-245 MB 51 14 0 -105 23 4 0 189 83

GOES* GRC-245 SL 51 14 0 -105 2 4 0 168 51

GOES** GRC-245 MB 51 7 0 -105 23 4 0 182 62

GOES** GRC-245 SL 51 7 0 -105 2 4 0 161 45

GOES BL GRC-245 SL 51 -10 0 -105 2 4 0 144 32

*GOES antenna diameter is 16 m, antenna height is 10 m, antenna gain is 14 dBi for a 5 degree antenna elevation angle

**GOES antenna gain is 7 dBi for a 10 degree antenna elevation angle

*** Cable loss from J/F 12 for GRC-245
DoD IMT-2000 Assessment

C-30

C.6.1.2 2025-2110 MHz Band Assessment

The TRR systems do not have spectrum available to operate in the 2025-2110 MHz band. The 2025-

2110 MHz band must be allocated for Government fixed and mobile operations to allow the TRR

access to the band. In addition, the TRR can not share the band with the ENG because of the large

number of ENG systems and the large distance separation required for compatible operations. If the

ENG were moved to a different frequency band, the TRR would have access to most of the band at

sites that were 216 km from SGLS sites and 83 km from space research earth-terminal sites.

C.6.1.3 2200-2290 MHz Band

The 2200-2290 MHz band is a government band and the DoD is the principal user. The band is

allocated to government fixed and mobile services on a primary basis, constrained to LOS systems

only, and to space research, space operations, and earth exploration satellite (EES), also on a primary

basis, specified for satellite-to-earth and satellite-to-satellite paths. The SGLS functions in the band

include tracking launch and space vehicles, telemetry from both launch and space vehicles, and

command operations. The SGLS downlink in the band provides tracking return signal and telemetry

functions. This band is used for the downlink of the NASA Tracking and Data Relay Satellite with

more than 15 frequencies used at White Sands Missile Range (WSMR), Greenbelt, MD, and Merritt

Is., FL. Critical guided missile (weapons) telemetry is also included in the band.

C.6.1.3.1 SGLS Downlink

The downlink associated with the 2025-2110 MHz and 1760-1840 MHz SGLS uplinks operates in

the 2200-2290 MHz band. The SGLS downlink supports transponded range code, range rate

determination, space vehicle State of Health (SOH) and mission data. The SGLS locations analyzed

are the same as for the uplink analysis, the New Hampshire Station (NHS), the Colorado Tracking

Station (CTS), the Eastern Vehicle Checkout Facility (EVCF) and the Onizuka Air Station (OAS).

The data on the SGLS receiver is provided in Table C-18.3

 

3

 Space and Missile Systems Center, Standardized Interface Specification between AF Satellite Control Network

Common User Element and Comm/range Segment and Space Vehicle, AFSCN SIS-000502A, El Segundo, CA: AFSCN,

22 October 1997.
DoD IMT-2000 Assessment

C-31

Table C-18. SGLS Receiver Parameters

Desired Signal Telemetry 1024 kb/s

Receiver Bandwidth (MHz) 1.0 (-3 dB)

Receiver Noise Power Density -178 dBm/Hz

Receiver Noise -118 dBm

Sensitivity -108 dBm

Interference Threshold (I/N = -10 dB) -128 dBm

Mainbeam Antenna Gain (7 m parabola) 41.5 dBi

Antenna Gain Off Boresight 23 dBi (3 deg), 16 dBi (5 deg), 12 dBi (10 deg)

The interference power from the TRR transmitter to the SGLS downlink receiver is calculated using

the standard received power equation and the results are provided in Table C-19. The distance

separation requirements between the TRR and the SGLS are more restrictive for the SGLS uplink to

TRR interference interactions. The distance separation between TRR and SGLS to avoid interference

range from 216 to 59 km in the 2025-2110 MHz band and from 132 to 49 km in the 2200-2290 MHz

band. The TRR may have difficulty gaining access to spectrum in either frequency band at TRR sites

such as Fort Carson which are near SGLS sites.

Table C-19. Interference Calculations For Tactical Radio Relay to SGLS Receiver

2200-2290 MHz Band

Interference Path Source Transmitter Data Victim Receiver Data FDR

Path 

Loss Distance

Source Victim TX Power TX Antenna TX Cable* Inter Threshold** RX Antenna* RX Cable SEM

dBm dBi dB dBm dBi dB dB dB Km

GRC-245 MB SGLS *** 32 25 5 -128 23 0 3 200.0 132

GRC-245 MB SGLS  32 25 5 -128 16 0 3 193.0 97

GRC-245 MB SGLS** *** 32 25 5 -128 12 0 3 189.0 80

GRC-245 SL SGLS *** 32 2 5 -128 23 0 3 177.0 58

GRC-245 SL SGLS  32 2 5 -128 16 0 3 170.0 52

GRC-245 SL SGLS** *** 32 2 5 -128 12 0 3 166.0 49

* Cable loss from J/F 12 for GRC-245

** Desired signal at sensitivity, I/N = - 10 dB

***SGLS antenna diameter is 7 m, antenna height is 10 m, antenna gain is 23 dBi for a 3 degree antenna elevation angle

 SGLS antenna gain is 16 dBi for a 5 degree antenna elevation angle

** ***SGLS antenna gain is 12 dBi for a 10 degree antenna elevation angle

C.6.1.3.2 Telemetry

Telemetry is heavily used in this band for such purposes as airborne weapons testing, aircraft flight

testing, and a wide variety of experimental and research projects. The parameters of a typical

telemetry link are provided in Table C-20. The airborne telemetry transmitter and the ground-based

telemetry receiver were analyzed to determine the required distance separation with the TRR radios.
DoD IMT-2000 Assessment

C-32

The results of the analyses are provided in Table C-21 for airborne telemetry interference to TRR

receivers and in Table C-22 for TRR interference to ground-based telemetry receivers.

Table C-20. Parameters of a Typical Telemetry Link

Frequency range 2200-2290 MHz

Transmitter Aydin Vector T400 Series Telemetry (J/F 12/6260)

Transmit power 20 W

Emission Bandwidth (MHz) 5.8 (-3dB), 5.9 (-20 dB), 13.0 (-60 dB)

Antenna gain (Transmit) 0 dBi

Antenna height 9144 m (Airborne)

Receiver Microdyne 1200 MR (J/F 12/5608

Receiver bandwidth (MHz) 6.0 (-3dB), 9.0 (-20 dB), 21.0 (-60 dB)

Receiver noise figure 5 dB (Assumed)

Receiver sensitivity -98 dBm (Receiver bandwidth not listed)

Receiver noise power -101dBm

Interfering signal threshold -107 dBm

Antenna gain (Receive) 28 dBi (Mainbeam), 20 dBi (Major Sidelobe)

Antenna height 5 m

 Table C-21. Interference Calculations for Airborne Telemetry Transmitter to Tactical Radio Relay Receiver

2200-2290 MHz Band

Interference Path Source Transmitter Data Victim Receiver Data FDR

Path 

Loss Distance

Source*** Victim TX Power TX Antenna TX Cable Inter Threshold* RX Antenna RX Cable** SEM

dBm dBi dB dBm dBi dB dB dB Km

Airborne Telemetry GRC-245 MB 43 0 0 -105 25 4.0 0 169.0 416

Airborne Telemetry GRC-245 SL 43 0 0 -105 2 4.0 0 146.0 372

*I/N = -6 dB

** Cable loss from J/F 12 for GRC-245

***Aircraft Telemetry, J/F 12/6260, aircraft height is 9144 meters, emission 6M00F1D 

Table C-22. Interference Calculations For Tactical Radio Relay to Telemetry Ground Receiver (J/F 12/5608)

2250 MHz

Interference Path Source Transmitter Data Victim Receiver Data FDR

Path 

Loss Distance

Source Victim TX Power TX Antenna TX Cable** Inter Threshold*** RX Antenna* RX Cable SEM

dBm dBi dB dBm dBi dB dB dB Km

GRC-245 MB Telemetry RX (10 MHz) 32 25 4 -107 20 0 0 180.0 55.1

GRC-245 SL Telemetry RX (10 MHz) 32 2 4 -107 20 0 0 157.0 36.7

*Telemetry receive antenna gain is 20 dBi (major sidelobe), antenna height is 5 meters 

** Cable loss from J/F 12 for GRC-245

*** 6 MHz BW, desired signal at sensitivity, I/N = - 6 dB
DoD IMT-2000 Assessment

C-33

The airborne telemetry transmitter has the potential to interfere with TRR receivers at a range of

416 km. The telemetry equipment is used at China Lake, CA; WSMR; Yuma, AZ; Eglin AFB, FL;

Utah Test Range, UT; Tonapoh, NV; Edwards AFB, CA; Barksdale AFB, AR; Nellis AFB, NV;

Point Mugu, CA, and Tyndal, FL. The TRR radios are expected to have little access to the 2200-

2290 MHz band within 416 km of test ranges because of the heavy use of telemetry frequencies at

ranges.

C.6.1.4 2200-2290 MHz Band Assessment

The 2200-2290 MHz is a critical band for SGLS and other satellite link operations because

interference can disrupt satellite control. The separation distance of 132 km is required between TRR

transmitters and the satellite downlink receivers to avoid interference. The large number of satellite

control frequencies and the large separation distance is expected to eliminate most frequencies from

TRR use around earth terminal sites in the 2200-2290 MHz band. In addition, TRR radios are

expected to have little access to the 2200-2290 MHz band within 416 km of test ranges because of

potential interference from telemetry operations. The allocation of the Air Combat Training System

(ACTS) to the 2200-2290 MHz band would restrict TRR operations in the band at many TRR sites.

Many of the current ACTS 1755-1850 MHz sites are the same sites (or are near sites) that are

protected with indefinite 1710-1755 MHz band protection under OBRA-93 to accommodate the

TRR. The incompatibility between the TRR and the ACTS is expected to continue for operations in

the 2200-2290 MHz band.

C.6.1.5 2500-2690 MHz Band

In the United States, the 2500-2690 MHz band is currently used by the Instructional Television Fixed

Service (ITFS), Multipoint Distribution Service (MDS), and Multichannel Multipoint Distribution

Service (MMDS). The terms MDS and MMDS are often used interchangeably. The ITFS provides

formal classroom instruction, distance learning, and videoconference capability to educational users

throughout the nation. The MDS provides a commercial video programming service in this

frequency band, often using leased ITFS spectrum There are four basic service offerings by

ITFS/MDS: analog video, digital video, unidirectional digital data, and bi-directional digital data.

Traditional one-way ITFS/MDS systems provide one-way multichannel video programming to users

or subscribers. The main station transmitter broadcasts to multiple receive sites located within the

56.3 kilometers service area. A 125 kHz response station transmitter may be located at the receive

site.
DoD IMT-2000 Assessment

C-34

In a two-way MDS/ITFS system, a main station transmitter is used to send data using digital

modulation to numerous users. Each user has at least one response station transceiver with its receive

antenna oriented towards the main station and its transmit antenna oriented towards its associated hub

station.

There are 2,175 ITFS licenses throughout the United States with over 70,000 locations serving as

registered receive sites and MDS currently has 2,570 station licensees and conditional licensees.

The technical parameters of the ITFS/MDS one-way main station transmitter/receiver and one-way

response station transmitter/receiver are provided in Table C-23 and C-24, respectively.4

Table C-23. ITFS/MDS One-way Main Station Transmitter and Receiver

Transmitter Spectrum 2500-2686 MHz

Emission Bandwidth 6 MHz

Power (EIRP) 2000 Watts

Modulation Video/Audio

Receiver Spectrum 2686-2690 MHz

Receiver Bandwidth 125 kHz

Modulation AM or FM

Antenna Gain 20 dBi (assumed)

Noise Figure 2.5 dB

Receiver Noise - 120.5 dBm (typical –107 dBm to –127 dBm)

Interference Threshold -126.5 dBm

Table C-24. ITFS/MDS One-way Response Station Transmitter and Receiver

Transmitter Spectrum 2686-2690 MHz

Emission Bandwidth 125 kHz

Power (EIRP) 40 Watts

Modulation AM or FM

Receiver Spectrum 2500-2686 MHz

Receiver Bandwidth 6 MHz

Modulation Video/Audio

Antenna Gain 20 dBi (Assumed)

Noise Figure 2.5 dB

Receiver Noise -103.5 dBm

Interference Threshold* -98 dBm

*Based on a 45 dB desired/undesired ratio with response station 35 miles from main station

 

4

 Federal Communications Commission, Interim Report, Spectrum Study of the 2500-2690 MHz Band, 15 November

2000.
DoD IMT-2000 Assessment

C-35

The interference analysis of interactions between the TRR and the ITFS/MDS one-way main station

and response station is provided in Tables C-25 to C-28. The two-way ITFS/MDS system was not

analyzed because the systems are still in development and interference thresholds have not been

finalized for the ITFS/MDS digital modulations.

Table C-25. Interference Calculations ITFS/MDS Main Station Transmitter to AN/GRC-245

ITFS/MDS main station transmitter authorized 2500-2686 MHz with a 6 MHz signal bandwidth

Interference Path Source Transmitter Data Victim Receiver Data FDR

Path 

Loss Distance

Source Victim TX EIRP TX Antenna* TX Cable Inter Threshold*** RX Antenna RX Cable** SEM

dBm dBi dB dBm dBi dB dB dB Km

ITFS/MDS GRC-245 MB 63 0 1 -105 25 5 0 187.0 97.0

ITFS/MDS GRC-245 SL 63 0 1 -105 2 5 0 164.0 73.0

*ITFS/MDS MainStation antenna height is 90 meters

** Cable loss from J/F 12 for GRC-245

***Desired signal at sensitivity, I/N = - 6 dB

Table C-26. Interference Calculations for AN/GRC-245 to ITFS/MDS Main Station Receiver

ITFS/MDS main station receiver authorized 2686-2690 MHz with a 125 kHz signal bandwidth

Interference Path Source Transmitter Data Victim Receiver Data FDR

Path 

Loss Distance

Source Victim TX Power TX Antenna TX Cable**Inter Threshold*** RX Antenna* RX Cable SEM

dBm dBi dB dBm dBi dB dB dB Km

GRC-245 MB ITFS/MDS 32 25 5 -126.5 20 1 12 185.5 94.0

GRC-245 SL ITFS/MDS 32 2 5 -126.5 20 1 12 162.5 72.0

*ITFS/MDS MainStation antenna height is 90 meters, antenna gain assumed 20 dBi

** Cable loss from J/F 12 for GRC-245

***Based on I/N= -6dB, receiver bandwidth = 125 kHz and noise figure = 2.5 dB

Table C-27. Interference Calculations for AN/GRC-245 Transmitter to ITFS/MDS Response Station Receiver

ITFS/MDS response station receiver authorized 2500-2686 MHz with a 6 MHz signal bandwidth

Interference Path Source Transmitter Data Victim Receiver Data FDR

Path 

Loss Distance

Source Victim TX Power TX Antenna TX Cable** Inter Threshold*** RX Antenna* RX Cable SEM

dBm dBi dB dBm dBi dB dB dB Km

GRC-245 MB ITFS/MDS MB 32 25 5 -98 20 1 0 169.0 50

GRC-245 SL ITFS/MDS MB 32 2 5 -98 20 1 0 146.0 32

GRC-245 MB ITFS/MDS SL 32 25 5 -98 2 1 0 151.0 36

GRC-245 SL ITFS/MDS SL 32 2 5 -98 2 1 0 128.0 19

*ITFS/MDS Response Station antenna height is 10 meters, antenna gain assumed 20 dBi

** Cable loss from J/F 12 for GRC-245

***Based on S/I = 45dB, receiver bandwidth = 6 MHz
DoD IMT-2000 Assessment

C-36

Table C-28. Interference Calculations for ITFS/MDS Response Station Transmitter to AN/GRC-245 Receiver

ITFS/MDS response station transmitter authorized 2686-2690 MHz with a 125 kHz signal bandwidth

Interference Path Source Transmitter Data Victim Receiver Data FDR

Path 

Loss Distance

Source Victim TX EIRP TX Antenna* TX Cable Inter Threshold*** RX Antenna RX Cable** SEM

dBm dBi dB dBm dBi dB dB dB Km

ITFS/MDS MB GRC-245 MB 46 0 1 -105 25 5 0 170.0 51.0

ITFS/MDS MB GRC-245 SL 46 0 1 -105 2 5 0 147.0 33.0

ITFS/MDS SL GRC-245 MB 28 0 1 -105 25 5 0 152.0 37.0

ITFS/MDS SL GRC-245 SL 28 0 1 -105 2 5 0 129.0 20.0

*ITFS/MDS Response Station antenna height is 10 meters

** Cable loss from J/F 12 for GRC-245

***Desired signal at sensitivity, I/N = - 6 dB

C.6.1.6 2500-2690 MHz Band Assessment

The distance separation required to avoid interference between the TRR and the ITFS/MDS main

stations is 97 km. The distance separation required to avoid interference between the TRR and the

ITFS/MDS response stations is 51 km. However, the response stations are distributed around the

main station at a distance of up to 56.3 km. As a result, the distance separation requirement between

the TRR and the ITFS/MDS main station, based on the response station interference threshold, is

107.3 km. The 2175 ITFS and 2570 MDS main stations would require a separation distance of

107.3 km for TRR in-band operations. If the band can be segmented to provide some frequencies for

exclusive TRR operations, the TRR could successfully utilize that portion of the band. The band

made available for military use would have to be allocated to government use on a primary basis with

equivalent regulatory protection.

C.6.2 Operational Impact

The MSE AND TRI-TAC impacts under this option are virtually the same as those described under

Option 2.

The impacts to amphibious and general Marine Corps battlefield training would be virtually the same

as those desribed under Option 2.

C.7 Option 4 – Vacate 1755-1850 MHz

C.7.1 Technical Assessment

The elimination of the 1755-1850 MHz band at all DoD TRR sites would stop operations of TRR

duplex links at all sites where the 1710-1755 MHz band is not protected indefinitely by OBRA-93.
DoD IMT-2000 Assessment

C-37

TRR duplex frequency assignments would not be possible without access to 1710-1850 MHz

frequencies because of the requirement for a minimum of 50.125 to 63.0 MHz frequency separation

between transmit and receive frequencies. The only band available for TRR operations,

1350-1390 MHz, can not provide the needed frequency separation. The sites without spectrum for

TRR operations would include Fort Hood and Fort Carson. Some sites have access to the

1432-1435 MHz band and one high data-rate duplex link could operate at these sites.

The 2025-2110 and 2500-2690 MHz bands have been assessed for TRR use and no spectrum was

identified for the TRR. The 2200-2290 MHz band is allocated for government fixed and mobile

operations, but the current users of the band must be protected. The separation distance of 132 km is

required between TRR transmitters and the satellite downlink receivers to avoid interference. The

large number of satellite control frequencies and the large separation distance is expected to eliminate

most frequencies from TRR use around earth terminal sites in the 2200-2290 MHz band. In addition,

TRR radios are expected to have little access to the 2200-2290 MHz band within 416 km of test

ranges because of potential interference from telemetry operations. The 2200-2290 MHz band is

being investigated for ACTS use as an alternate to the current 1755-1850 MHz band. The frequencydistance separation requirements between the ACTS and the TRR are comparable to the requirements

for airborne telemetry. As a result, the 4400-4940 MHz band was assessed as an alternate frequency

band for TRR operation.

2003 and 2006 Time Frame. The loss of the 1755-1850 MHz band would disrupt TRR operations at

sites without access to the 1710-1755 MHz band until AN/GRC-245 type radios with an ability to

operate above 2000 MHz become widely available after 2006.

2010 Time Frame. The replacement of current TRR equipment with AN/GRC-245 type radios

operating above 2000 MHz could be accomplished after the 2006 time frame. The government

spectrum available above 2000 MHz and the non-government 2500-2690 MHz frequency band were

investigated in the previous section to see if training requirements could be met in these bands and

little spectrum was identified. The 4400-4940 MHz band was investigated as a candidate for TRR.

C.7.1.1 4400-4940 MHz Band

The 4400-4940 MHz band was investigated for TRR operations; however, this study did not

investigate the 4400–4940 MHz band for worldwide spectrum availability for the TRR. Migration of

TRR systems that operate in the 1755-1850 MHz band to the 4400-4940 MHz band is not feasible

due to the operational impacts resulting from the significant difference in technical characteristics of

the bands and due to the limitations required to protect incumbent users in the 4400-4940 MHz band.
DoD IMT-2000 Assessment

C-38

The 4400–4940 MHz band supports the operations of many fixed and transportable line-of-sight and

tropospheric scatter radio relay systems, for the exchange of weapons sensor data, telemetry, and

command links for weapons and range systems. The systems are generally wideband, multichannel

systems and are used by all the services.

The relocation of TRR operations to the 4400 – 4940 MHz band would involve a design of a new

series of radios, significant changes in operational doctrine, and manpower increases to restore

essential military capabilities currently supported by operations in the 1755-1850 MHz band.

Parameters of notional TRR systems are provided in Table C-29.

Table C-29. Parameters of Notional Tactical Radio Relay Systems in the 4400-5000 MHz Band

Frequency range 4400 – 5000 MHz

Transmit power 1.6 W

Emission Bandwidth (MHz)* 2.0 (-3 dB)

Antenna gain 32 dBi at 4.4 GHz

Antenna height 30 m

Receiver bandwidth (MHz)* 6.7 (-3 dB)

Interfering signal threshold* -105 dBm

Cable losses 6 dB @ 4700 MHz

A high antenna gain is needed to compensate for the increased link losses at 4400-4940 MHz.

However, the 4400–4940 MHz antenna would have a beamwidth of approximately 3.5 degrees. The

narrow-beam antenna will significantly reduce the mobility and survivability of military personnel

and units. In some situations, link distances would be significantly reduced thereby resulting in

increased numbers of TRR systems with associated increases in manpower.

A notional TRR system (Table C-29) was evaluated for electromagnetic compatibility (EMC) with the

incumbent equipment in the 4400–4940 MHz band. The incumbent equipment analyzed included the

AN/TRC-170, AN/GRC-222, and the Cooperative Engagement Capability (CEC).

AN/TRC-170. The AN/TRC-170 is a transportable radio terminal providing full-duplex digital voice

and data at ranges up to 330 km by means of line-of-sight or tropospheric scatter modes of

propagation in the 4400–4999 MHz band. The parameters of the AN/TRC-170 used in the analysis

are presented in Table C-30.
DoD IMT-2000 Assessment

C-39

Table C-30. Parameters of the AN/TRC-170 From J/F 12/4480/4

Frequency range 4400 – 4999.9 MHz

Transmit power 2 KW

Emission Bandwidth (MHz) 5.0 (-3dB), 7.0 (-20dB), 13.0 (-60dB)

Antenna gain 40.5 dBi (mainbeam)

Antenna height 5 m

Receiver bandwidth (MHz) 4.0 (-3dB), 6.0 (-20dB), 10.0 (-60dB)

Receiver noise figure 5 dB (estimate)

Receiver sensitivity NA

Receiver noise power -103 dBm

Interfering signal threshold -109 dBm

Cable losses NA

Waveform 7M00M7D

The AN/TRC-170 has the greatest number of frequency assignments in the band and there are three

versions currently in use. The AN/TRC-170(V2) version has typical parameters based on a review of

the frequency assignment data files and this version was used in the analysis. The AN/TRC-170

provides high capacity backbone communications in tactical, strategic and administrative

environments and operates in close proximity to the MSE, TRI-TAC, and DWTS systems. The

distance separation required to eliminate interference between the AN/TRC-170 and a notional TRR

system was calculated using the standard interference equation and the results are provided in Figures

C-9 and C-10.
DoD IMT-2000 Assessment

C-40

0

20

40

60

80

100

120

140

0 5 10 15 20 25 30 35

Off Tuned (MHz)

Distance Separation (km)

SL-MB

SL-SL

BL-SL

Figure C-9. Frequency-Distance Separation for AN/TRC-170 to a TRR

0

10

20

30

40

50

60

01234567

Off Tuned (MHz)

Distance Separation (km)

MB-SL

SL-SL

SL-BL

Figure C-10. Frequency-Distance Separation for a TRR to AN/TRC-170
DoD IMT-2000 Assessment

C-41

The frequency separation requirements for AN/TRC-170 transmitters and TRR receivers are in the

range of 12 to 18 MHz for co-located radios (distance separations of approximately 200 meters) with

sidelobe or backlobe antenna orientations. The frequency-distance separation requirements for the

AN/TRC-170 high power mode are larger (by a factor of two or three) than the separation

requirements for LOS microwave radios and additional spectrum will be required to provide

compatible frequency assignments.

AN/GRC-222. The AN/GRC-222 is a high traffic digital radio that operates in a LOS mode of

propagation. The AN/GRC-222 has a capacity to 18.72 mbps of data using 8-level phase shift keying

(PSK) modulation. The radio parameters of the AN/GRC-222 are provided in Table C-31, and the

results of the analysis are provided in Figures C-11 and C-12. The collocated frequency-separation

requirement between the AN/GRC-222 and a TRR receiver is approximately 8 MHz.

Table C-31. Parameters of the AN/GRC-222 J/F 12/6204

Frequency range 4400 – 5000 MHz

Transmit power 0.8 W

Emission Bandwidth (MHz)* 5.8 (-3dB), 7.6 (-20dB), 12.2 (-60dB)

Antenna gain 33 dBi (mainbeam)

Antenna height 30 m

Receiver bandwidth (MHz)* 12.0 (-3dB), 19.0 (-20dB), 46.0 (-60dB)

Receiver noise figure 7 dB (assumed)

Receiver sensitivity* -66 dBm @ 18720 Kb/s and BER = 10E-5

Receiver noise power* -91 dBm (assumed)

Interfering signal threshold* -97 dBm (assumed)

Cable losses 6 dB @ 4700 MHz (assumed)

Waveform 7M00G2D, 8 PSK

*18720 kb/s
DoD IMT-2000 Assessment

C-42

0

5

10

15

20

25

30

35

40

45

50

0 2 4 6 8 10 12

Off Tuned (MHz)

Distance Separation (km)

SL-MB

SL-SL

Figure C-11. Frequency-Distance Separation for AN/GRC-222 to a TRR
DoD IMT-2000 Assessment

C-43

Frequency-Distance Separation for AN/GRC-245 to AN/GRC-222

0

5

10

15

20

25

30

35

40

45

50

0 5 10 15 20 25 30

Off Tuned (MHz)

Distance Separation (km)

SL-MB

SL-SL

Figure C-12. Frequency-Distance Separation for a TRR to AN/GRC-222

Cooperative Engagement Capability (CEC). CEC is a system that provides the means to conduct

coordinated Anti-Air Warfare (AAW) area defense. All Cooperating Units (CU) that participate in a

CEC network exchange sensor data in near real time to form an identical composite track and

identification air surveillance picture on each CU. This sensor cooperation function allows targets to

be detected and compositely tracked that a single individual sensor could not track. The composite

air picture provides the means for a battle force to accomplish optimized weapon system assignments

and the coordinated engagements of threats. CEC is implemented via a Cooperative Engagement

Processor (CEP) and a Data Distribution System (DDS). The CEP is a computer system responsible

for forming the composite track and identification data base, and for coordinating engagements. The

DDS is an radio frequency (RF) network responsible for the secure, environmentally resistant transfer

of sensor and weapon data among the CUs. CEC is currently being deployed aboard Navy E-2C

aircraft and the major Navy surface combatants, carriers, and amphibious class ships. CEC is also
DoD IMT-2000 Assessment

C-44

now in development for deployment with the USA PATRIOT, USAF AWACS, and USMC AN/SPS59 radar systems. The parameters for CEC are provided in Table C-32.5

Table C-32. Parameters of the Cooperative Engagement Capability (CEC) from FCC-00-63

Frequency 4929 MHz and Below

Emission Bandwidth 22 MHz

Maximum Transmit Power (EIRP) 630 kW

Out-of-Band Emissions +/- 7.65 MHz (-3 dBc), +/- 12.1 MHz (-30 dBc)

Transmitter Noise +/- 25.6 MHz Less Than –145 dBc/Hz

The analysis of CEC interference to a relocated TRR concluded that band sharing and band

segmentation are not feasible. For band sharing, the separation distance required to reduce CEC inband signals to a maximum allowed interference level was determined to be beyond the RF horizon,

which could exceed 200 NM for airborne CEC platforms. Since both TRR and CEC may operate in

close proximity, that separation distance is not acceptable. For band segmentation, the distance may

reduce to 30 nmi (55 km), which is again unacceptable. Most significant, for band segmentation, CEC

may have to incur a 250 MHz reduction in usable spectrum. That spectrum reduction would have

significant and unacceptable impacts on CEC combat readiness and operation.

C.7.1.2 4400-4940 MHz Band Assessment

Battle Space management doctrine and tactics will require collocation of CEC and TRR aboard Navy

ships and ashore elements of Marine and Army Air Defense radars and Missile Batteries, among

other things. However, relocation of TRR systems from the 1755-1850 MHz band into the 4400-

4940 band would preclude simultaneous use of CEC and TRR during, among other things, carrier

battle group operations, amphibious operations, and joint operations ashore. It is contrary to battle

space management doctrine and tactics to forgo the simultaneous use of critical warfighting systems.

Trade-offs between use of anti-air warfare systems (like CEC) and systems for the exchange of

tactical data (TRR) are unacceptable.

If AN/TRC-170 systems and the TRR systems both operate in this same frequency band, additional

spectrum would be required to provide larger guardbands around the AN/TRC-170 emissions. An

additional spectrum requirement of 50 MHz would be necessary to provide the guardband with CEC.

 

5

 Federal Communications Commission, FCC Proposes Licensing and Service Rules for the 4.9 GHz Spectrum

Band, NPRM FCC-00-63, 29 February 2000.
DoD IMT-2000 Assessment

C-45

Accommodating the TRR in the 4400-4940 MHz band could require a 200 to 250 MHz reduction in

CEC spectrum and have a significant impact on CEC combat readiness and operations. The major

operational impact of a decrease in RF spectrum is a decrease in the number of CUs that can

simultaneously participate in a CEC network. Each CU increases the warfighting effectiveness of the

battle force by providing: (1) sensors that uniquely contribute to the formation and update of a

composite track and identification data base, and/or (2) weapon systems that uniquely contribute to

target engagement based on that composite data base. The decrease in bandwidth, then, degrades the

overall warfighting capabilities of a CEC network, the individual combatants that comprise the

network, and the individual combatants that must be purposely omitted from the network.

C.7.2 Operational Impact

Vacating the entire 1755-1850 MHz band is not an option for the Army. This band is a key element

of Army battlefield communication networks for the foreseeable future, including the new HCLOS

radio. Alternate frequency bands above the mid 2 GHz area may not be suitable for tactical

microwave systems. The 1700 MHz band is used for mobile communications because the

propagation characteristics allow for better penetration of foliage, use of inexpensive coaxial cables

instead of expensive wave guides, and have a wide beam width allowing for quicker path alignment.

These characteristics are critical to tactical mobile communications units because of their mission to

provide the Army with the ability to relocate command centers quickly. Moving the communications

network to a higher frequency band would negate many of these factors, thus decreasing the

operational utility of the system. Otherwise, over the air training exercises would be severely

restricted at most of the training locations available to the Army. The operational implications from

the inability to train in the US would directly impact combat operations. Deployment and

maintenance of the ACUS/MSE system during a crisis and network management of large

brigade/division/corps level units will be degraded because of the lack of trained operators.

Vacating the entire 1755-1850 MHz band is unacceptable for the Marine Corps until new frequency

space is identified and a new system is developed. No existing materiel solutions are available for

fielding until at least the 2010 time frame. Operational impacts are worse than Option 1, as no

capability would remain for amphibious and battlefield training.
DoD IMT-2000 Assessment

D-1

APPENDIX D – POTENTIAL FOR INTERFERENCE

BETWEEN IMT-2000 ENVIRONMENT AND AIR COMBAT

TRAINING SYSTEMS (1755-1850 MHZ)

The 1755-1850 MHz frequency band is used by Air Combat Training Systems (ACTS) such as the Air

Force’s Air Combat Maneuvering Instrumentation (ACMI) and the identical Navy Tactical Air Combat

Training System (TACTS). These existing ACTS systems transmit data to the aircraft on either 1830 or

1840 MHz and receive data from the aircraft on either 1778 MHz or 1788 MHz. Phase-modulated

ranging tones and 198.4 kb/s data, using frequency shift keying, are transmitted. Point-to-point links in

this band are also used to communicate the data from remote sites to a central location.

Current plans call for existing ACTS to be operating well past 2010. Under the current plan, the Joint

Tactical Combat Training System (JTCTS) would not begin replacing existing ACTS until after 2006,

with a replacement schedule into at least the 2010 time frame. The JTCTS data links operate air-toground, ground-to-air, and ground-to-ground, and can tune across the band 1710-1850 MHz in 5 MHz

increments. The JTCTS data link signal structure is l6-ary, orthogonal signaling, with 0.351, 0.703, and

1.406 Mb/s data rates combined with either 5.63 or 22.5 Mc/s pseudorandom spreading codes.

This appendix addresses the possible interference between IMT-2000 base and mobile stations and the

ACTS, also described as the TACTS/ACMI and the JTCTS operating in the frequency band

1755-1850 MHz.

D.1 OPERATIONAL MISSION OVERVIEW

The mission of the Air Force ACTS ranges, as prescribed in Air Combat Command (ACC) regulation

23-24, is to “maximize the combat readiness, capability, and survivability of participating units by

providing realistic training in a combined air, ground, and electronic threat environment while providing

for a free exchange of ideas between forces.” Specifically, the range objectives are to force the

crewmember to cope with an action-reaction sequence of threat events that (1) reflects the realities of

imperfect intelligence and the limitations of operational plans, (2) yields an opportunity to practice

handling larger amounts of information under stress, and (3) provides recognition that other players are

influencing the scenario, the threat, and the outcome.

The ACTS supports simultaneous engagement of multiple air combat participants in state-of-the-art airto-air, air-to-ground, ground-to-air, and electronic warfare (EW) environments. The system provides

real-time monitoring and post mission reconstruction capabilities to enhance debriefing of combat
DoD IMT-2000 Assessment

D-2

aircrews. The system provides aircrew training such as aircraft handling capability, basic fighter

maneuver, or intercept and air combat training sorties up to and including large composite force training.

Live air combat training is essential in order to expose pilots and combat systems operators to the

complexities and stresses under which they are expected to execute their intended missions in actual

combat. A key part of this training is the capability to provide accurate feedback directly to the aircrews

and the probable or actual results of their actions. The required training environment and feedback

capability can only be provided with special instrumentation such as ACTS and JTCTS. The timerelated data, provided by this instrumentation—aircraft instantaneous position, velocity vector and

accelerations, maneuvering history, and combat system activity history—forms the only possible

objective information for feedback. This data supports weapons engagements performed with simulated

weapons fly-outs and endgame results, instead of utilizing real weapons for obvious safety reasons and

the prohibitive cost of expending actual weapons in a training situation. The ability to provide this type

of support ensures each flight hour flown is maximized in terms of effectiveness and cost efficiency.

Without the training feedback from ACTS, aircrews may develop the habit of launching their air-to-air

or air-to-ground weapons “out of the envelope” or not maintaining radar-lock throughout the simulated

launch of a weapon. These bad habits can be deadly in air combat. Aircrews can deploy and fly in

support of the combatant commanders without ACTS training, but in the words of one Air Force fighter

pilot, “It’s like sending a little league baseball player straight into the big leagues. With little or no

training and experience, the player will most likely strike out. In our case, we don’t strike out, we get

shot down.” In addition, both the Air Force and Navy systems are used by allied nations during training

in the US. This opportunity to train in coalition operations is invaluable as air operations over Kosovo

showed.

In the early 1990s, the Navy began development of a system that would not only replace and upgrade

their “legacy” TACTS but also provide a capability to take the TACTS function to sea with a carrier

battlegroup. Subsequently, the Office of the Secretary of Defense (OSD) mandated expansion of the

Navy’s Tactical Combat Training System (TCTS) program to cover Joint Air Force and Navy

requirements for the next-generation ACTS. The initial focus of the Joint TCTS (JTCTS) program is on

development and production of the mobile (“rangeless”) configuration, which does not impact the

continental US (CONUS)-based IMT-2000 deployment. Development and production of the fixed

range configuration (and replacement of all the legacy ACTS within CONUS) is not currently scheduled

until the 2008-2017 time frame. While some existing “fixed” ranges may be replaced by rangeless

capability, Major Training Centers (MTCs) of all services provide infrastructure that are planned to be

preserved and modernized with JTCTS derived “fixed applications.”
DoD IMT-2000 Assessment

D-3

TACTS is the primary tool at the Navy Fleet Replacement Squadron (FRS) and Marine Training

Squadron level, where the aircrews first learn how to fly and fight with the specific aircraft they will

operate in the Fleet. ACTS is essential to the advanced tactical training—Strike-Fighter Advanced

Readiness Program (SFARP), Fighter Advanced Readiness Program (FARP), and Top Gun—that the

F/A-18 and F-14 aircrews go through as their squadrons prepare for eventual carrier deployment.

TACTS is critical to the ability of the Naval Strike and Air Warfare Center (NSAWC) and Marine

Aviation Weapons And Tactics Squadron One (MAWTS-1) to prepare and evaluate the ability of carrier

air wings and Marine aviation tactical squadrons to carry out complex coordinated combat operations.

Similar Air Force schools and large air exercises like Red Flag at Nellis Range rely on ACMI systems to

conduct similar training regimen.

JTCTS systems will be fielded more widely in the future to support more robust “joint” training, as the

Services become more interdependent. JTCTS will fulfill the same functions as ACTS with added

flexibility to support the rangeless training concept with fewer constraints than what is currently

associated with the ACTS ground infrastructure.

D.2 SYSTEM DESCRIPTIONS

Technical characteristics of the TACTS/ACMI and JTCTS, together with relevant operational

assumptions, are given in the following paragraphs.
DoD IMT-2000 Assessment

D-4

D.2.1 TACTS/ACMI Characteristics

D.2.1.1 System Characteristics

Characteristics of the TACTS/ACMI system are given in Tables D-1, D-2, and D-3. Values are those in

the frequency allocation applications,1,2,3,4

 unless noted otherwise. Unique radio frequency (RF)

parameters of some of the Air Force ACTS ranges are not considered in this analysis. Certain

parameters of the internal AIS units were not available. The values were estimated based on the

corresponding parameters of the Airborne Instrumentation Subsystem (AIS) pod units, and the shaded

cells of Tables D-1 and D-2 indicate these parameters. For transmitter emission bandwidths and

receiver IF bandwidths, as well as harmonic and spurious levels, the DD Form 1494 values were used

instead of the specified values.5

 It was felt the specified values represented a limit not to be exceeded,

while the 1494 values more closely represented actual system characteristics. TACTS/ACMI

frequencies and the link types associated with their use are listed in Table D-4.

D.2.1.2 Operational Considerations

In an earlier analysis for the Air Force Frequency Management Agency (AFFMA),6

 ground-to-air

separation distances of 78 and 35 km were used. These values correspond to 48.5 mi (42.1 nmi) and

21.75 mi (18.9 nmi) respectively. The specified nominal maximum range appears to be 65 nmi.7

 The

separation distances of 78 km (42.1 nmi) and 35 km (18.9 nmi) were used in the TACTS/ACMI portion

of this analysis.8

 1

Application for Equipment Frequency Allocation (DD Form 1494) for AN/TSQ-T4 Master Station and subsequent Notes to Holders,

J/F 12/4321, Washington, DC: MCEB, April 1975.

2

Application for Equipment Frequency Allocation (DD Form 1494) for AN/TSQ-T4 Remote Stations and subsequent Notes to

Holders, J/F 12/4322, Washington, DC: MCEB, April 1975.

3

Application for Equipment Frequency Allocation (DD Form 1494) for AN/TSQ-T4 Up Link and subsequent Notes to Holders, J/F

12/4323, Washington, DC: MCEB, April 1975.

4

Application for Equipment Frequency Allocation (DD Form 1494) for TACTS, ACMI AIS Pods and subsequent Notes to Holders,

J/F 12/4324/2, Washington, DC: Naval Air Systems Command, May 1987.

5

Fred Williar, Naval Air Systems Command, e-mail to Allan Baker, IITRI, Subject: More TACTS Data, Patuxent River NAS, MD,

September 27, 2000.

6

Wayne Wamback, The Potential for Interference Between IMT-2000 Systems and US DoD Systems Operating in the Frequency

Band 1755-1850 MHz, Annex 2, Alexandria, VA: AFFMA, 28 February 2000.

7

James E. Keeler, AAC/WMRR, e-mail to J. Don Simmons, Civ AAC/WMRR, Subject: DoD Forms for 1755 – 1850 MHz IMT-2000

Study, September 13, 2000.

8

 Fred Williar, Naval Air Systems Command, e-mail to Allan Baker, IITRI, Subject: TACTS AIS Data, Patuxent River NAS, MD,

September 27, 2000.
DoD IMT-2000 Assessment

D-5

Table D-1. TACTS/ACMI Transmitter Characteristics

Transmitter

Characteristic

TIS

Master

TIS

Remote

TIS

Uplink

AIS

Downlink

(Pod)a

AIS

Downlink

(Internal)d

Power (W) 20 1 or 5b 5 c 20 10-15 (min)e

Modulation Type FSK,PM FSK,PM FSK,PM FSK,PM FSK,PM

Modulation

Indices

0.9,0.3,0.3 0.9,0.3,0.3 9,3,3 9,3,3 8.2,2.7,2.7

Carrier Deviation

(FSK)

± 74.4 kHz ± 74.4 kHz ± 74.4 kHz ± 74.4 kHz ± 74.4 kHz

Data Rate (kb/s) 198 198 198 198 198

Widest Emission

Bandwidth (MHz)

-3 dB 0.6 0.6 3.0 2.0 3.0

-20 dB 0.8 0.8 7.0 8.0 7.0

-60 dB 2.1 2.1 12.0 12.0 12.0

Harmonic

Attenuation (dB)

70 70 70 85 85

Spurious

Attenuation (dB)

70 70 70 70 70

a

The calibration transponder at the master station is electronically identical to the AIS pod.

b

Depends on manufacturer. Cubic Corp. uses 1 W, ADT uses 5 W (Ref. 5).

c

20 W at Tyndall ACMI and Yukon MDS ranges (Ref. 5).

d

Data consolidated from Ref. 8.

e

15 W applies to AISI(K) (Ref. 8).

Table D-2. TACTS/ACMI Receiver Characteristics

Receiver

Characteristic

TIS

Master

TIS

Remote

TIS

Downlink

AISa

(Pod)

AIS

(Internal)d

Sensitivity

(dBm)

-95

(BER =

1x10-5)

-95

(BER =

1x10-5)

-95

(BER =

1x10-5)

-99

(10 dB S/N)

(BER =

1x10-5)

-95 dBm (100%

response), -99

dBm (50%

response)

Noise Levele

(dBm)

-110 -110 -110 -111 -111

IF Bandwidthb

(MHz)

-3 dB 1.5 1.5 1.5 1.2 1.2

-20 dB 5.0 5.0 5.0 3.0 3.0

-60 dB 12.0 12.0 12.0 8.0 8.0

Receiver

Selectivityc

(MHz)

-3 dB 1.5 1.5 1.5 1.2 1.2

-20 dB 2.9 2.9 2.9 3.0 3.0

-60 dB 7.4 7.4 7.4 6.8 6.8

Spurious

Response (dB)

60 60 85 85 85

a

The calibration transponder at the master station is electronically identical to the AIS pod.

b

Second IF bandwidth

c

Bandwidth of combined first and second IF stages.

d

Data consolidated from Ref. 8.

e

Calculated using 2.7 dB noise figure, from Ref. 5.
DoD IMT-2000 Assessment

D-6

Table D-3. TACTS/ACMI Antenna Characteristics

Antenna

Characteristic

TIS

Master

TIS

Remote

TIS

Uplink/

Downlink

AIS

(Pod)

AIS

(Internal)

Type Parabolic

(Dipole

Arrays)/

Broad

Beamwidth

Parabolic Crossed

Dipole

Array

Dipole Dipole

Gain (dBi) 28,24,

20d

/14.5

26 3.0 0 0

Polarization V & H V,H RHCP RHCP RHCP

Height (ft) 75

(300 max)e 100-150 160(100-150)e 30,000a,c 55,000-60,000a,b

a

Maximum altitude above mean sea level

b

From Reference 8.

c

Reference 5 gives a range of 10,000 to 30,000 ft. This reference also states that the tracking

instrumentation subsystem (TIS) is specified to track aircraft within altitudes of 500 ft. to 40,000

ft above the range floor.

d

Different values are given. The 20-dB value is given in Reference 1. Although a broad

beamwidth is usually desired, the antenna gain may depend on the installation.

e

Antenna height is site-dependent.

Table D-4. TACTS/ACMI Frequencies and Usage

Type of Link Frequencies (MHz)

Master-to-Remote 1768 or 1769

AIS-to-Remote (Downlink) 1788 “A” Pod or 1778 “B” Pod

Remote-to-Master 1797, 1802, 1807, 1812, 1817, 1822

Remote-to-AIS (Uplink) 1840 “A” Pod or 1830 “B” Pod

The maximum number of aircraft is stated to be 36 (Reference 7). For the Nellis ACTS and the Alaska

Upgrade (AAU), as many as 100 aircraft can be supported. In this analysis, the effect of the number of

aircraft flying at a given time was not considered.

Altitudes of 5000 m (16,400 ft) and 9000 m (29,530 ft) were used in Reference 6. A somewhat higher

maximum altitude of 40,000 feet above range floor is given in Reference 5, and altitudes of 55,000 to

60,000 feet are given for the internal AIS equipment (Reference 8). The 9000 m (approximately 30,000

ft) altitude was used in this analysis.

A representative sample of TACTS and ACMI training center sites is shown in Figure D-1.
DoD IMT-2000 Assessment

D-7

Figure D-1. Representative Sample of Air Combat Training Center Sites

D.2.2 JTCTS Characteristics

D.2.2.1 System Characteristics

Tables D-5, D-6, and D-7 contain characteristics of the JTCTS. Characteristics were obtained from the

frequency allocation application,9

 SRI International reports10,11 and material from the system

manufacturer which was provided by SRI International.12,13 The high-power mode of operation

(67.6 W) was assumed. The shaded boxes contain assumed values.

 9

Application for Equipment Frequency Allocation (DD Form 1494) for Joint Tactical Combat Training System (JTCTS)

Instrumentation Data Network, (Stage 4), J/F 12/06999/2, Patuxent River, MD, NAWCAD, 10 July 1998.

10David Hanz, Results from Phase 1a of the GSM-1800/JTCTS Datalink Signal Compatibility Test Program, Special Report 10240-

99-SR-110, Menlo Park, CA: SRI International, November 1999.

11US DoD Air Combat Training Systems Development Roadmap for Next Generation & Spectrum Compatibility Issues, dated 12

January 2000. Briefing given by D. Hanz of SRI International, 11 September 2000.

12Raytheon Systems Company, JTCTS Data Link Overview, Slide Package, undated, attachment to D. Hanz, SRI International, e-mail

to A. Baker, IITRI/JSC, September 25, 2000. Subject: Reference Material #1.

13 Dave Hanz, SRI International, e-mail to Allan Baker, IITRI, Subject: More Reference, 25 September 2000, with attachment

Raytheon Specification G644379 8 February 1996 CAGE Code 49956 Rev. A: 31 December 1996.
DoD IMT-2000 Assessment

D-8

Table D-5. JTCTS Transmitter Characteristics

Transmitter Characteristic Narrowband Wideband

Power (W) 7.6 or 67.6 7.6 or 67.6

Tuning Frequencies are selectable from 1710-1850 MHz in 5-MHz increments

(1755-1850 MHz in US&P).

Modulation Type OQPSK with DS spread spectrum, 16-ary orthogonal Walsh signaling

Data Rate (kb/s) 351.5625, 703.125, 1406.25 351.5625, 703.125, 1406.25

Chip Rate (Mc/s) 5.63 22.5

Protocol TDMA-100 ms frame,

Primary IDN: 25 slots/frame

Secondary IDN: 10 slots/frame

Error Detection and Correction Reed-Solomon FEC

Short Data Slots: (116,100)

Long Data Slots: (128,100)

Relay Slots: (56,40)

Emission Bandwidth (MHz)

-3 dB 2.1 4.8

-20 dB 5.63 22.5

-60 dB 22.5 90

Harmonic Attenuation (dB)

(2 & 3) 70 70

Other 80 80

Spurious Attenuation (dB) 80 80

Table D-6. JTCTS Receiver Characteristics

Receiver Characteristic

Sensitivity (dBm) -106.5 @ 14.1 dB Eb/No, 351.56 kb/s, RS coding

Noise Figure (dB) 4.5

Receiver Noise Level, dBmb -114.0 (352.6 kb/s), -111.0 (703 kb/s), -108 dBm

(1406 kb/s)

First IF Bandwidth (MHz) Narrowbandc Wideband

-3 dB 22.5 22.5

-20 dB 45 45

-60 dB 60 60

Implementation Losses (dB) 2

Spurious Response (dB) 60

Image Rejection (dB) 100

Intermediate Frequency (MHz) 400 a

It is expected that additional selectivity is present, at the second IF or baseband

b

In bandwidth equal to the bit rate.

c

No additional filtering is used for the narrowband mode.14

 14 David Hanz, SRI International, e-mail to Allan Baker, IITRI/JSC, 9 October 2000, Subject: JTCTS Characteristics.
DoD IMT-2000 Assessment

D-9

Table D-7. JTCTS Antenna Characteristics

Antenna

Characteristic

Instrumentation Data

Link

(Aircraft Fuselage

Mounted)

Instrumentation Data

Link

(Aircraft Pod

Mounted)

Ship-to-Shore

Link

Type 1⁄4 λ monopole blade 1⁄2 λ crossed dipoles Stacked dipole array

Gain (dBi) 2 6 8

Polarization V H,V V

Height (ft) 30,000 30,000

D.2.2.1.2 Operational Considerations

In Reference 6, ground-to-air separation distances of 78 and 35 km were used for both the

TACTS/ACMI and JTCTS analyses. These values correspond to 48.5 mi (42.1 nmi) and 21.75 mi (18.9

nmi) respectively. However, it is realized that for the JTCTS, the ground-to-air links are secondary and

tertiary links. The primary link is the air-to-air link, with a maximum distance of 150 nmi (278 km). A

separation distance of this magnitude plus a smaller one (78 km or approximately 50 mi) were used in

the analysis.

The maximum number of aircraft is stated to be 100 for JTCTS, according to discussions at a 25

September 2000 meeting with Naval Air Systems Command (NAVAIR) and SRI International

personnel and to Reference 7. Typical numbers of aircraft may be somewhat less. In this analysis, the

effect of the number of aircraft flying at a particular time was not considered.

Altitudes of 5000 m (16,400 ft) and 9000 m (29,530 ft) were used in Reference 6. Some of the material

provided for the TACTS system indicates that maximum altitudes may be higher (e.g., 40,000 to 60,000

feet). However, after coordination with JTCTS engineering and operational personnel, an altitude of

9000 m (approximately 30,000 ft) was used in both the TACTS/ACMI and JTCTS parts of the analysis.

D.3 COST ISSUES

D.3.1 Aircraft Combat Training Systems

The DoD is developing the next generation air combat training system to replace the existing ACTS

equipment. This system, called the Joint Tactical Combat Training System (JTCTS), is a Global

Positioning System (GPS)-based system. JTCTS, as designed, utilizes the 1755-1850 MHz band.

However, JTCTS can be retuned to a segment of the 1755-1850 MHz band or relocated to another band
DoD IMT-2000 Assessment

D-10

of comparable spectrum, given one’s availability. This is the key assumption regarding DoD proposed

mitigation approach for tactical aircraft training systems under the full-band loss option. If a

comparable band in S-band is not made available a much more expensive, complicated, and yet to be

defined alternative, will be required.

The proposed DoD mitigation plan for ACTS is to retune to the segmented band or relocate to an

alternate JTCTS band, accelerate immediately the development work necessary to reconfigure JTCTS

equipment to the operating band, and then to accelerate to the extent possible fielding of the system

considering the large number of aircraft affected and the number of ranges that utilize TACTS/ACMI

equipment. The acceleration can be large, as in the 2006 IMT-2000 build-out case, or more gradual in

the 2010 case. Given the current JTCTS program, relocating and fielding JTCTS for all legacy ACTS in

2006 is high risk (questionable feasibility) or in 2010 is medium to high risk even with immediate

funding. Table D-8 shows the cost impact of relocating JTCTS under the 2010 option assuming total

band loss to DoD.

Table D-8. Joint Tactical Combat Training System (JTCTS) (TY$M)

FY02 FY03 FY04 FY05 FY06 FY07 To Complete Total

JTCTS Acceleration 15.2 55.7 44.8 68.6 48.6 34.8 173.0 440.7

D.4 OPTION 1 – FULL BAND SHARING

D.4.1 TACTS/ACMI Technical Assessment

D.4.1.1 Interference from IMT-2000 into TACTS/ACMI Airborne Receivers

The calculation of aggregate IMT-2000 interference into the TACTS/ACMI and JTCTS airborne

receivers was done in a manner similar to that in Reference 6, which was based on the levels used in

Recommendation ITU-R M.687-2.15 Two training ranges were selected, Cherry Point Marine Corps Air

Station (MCAS), in the eastern US, and Nellis Air Force Base (AFB) in the western US. Both training

ranges were within LOS of at least one major metropolitan area. For each training range, a point within

the boundary of the flight area was selected, and metropolitan areas within the radio line of sight (LOS)

of this point were selected. The assumed aircraft receiver altitude was 9000 m (approximately 30,000

ft). For each city, the equivalent area was calculated, and the propagation loss was calculated using the

 15 International Telecommunication Union, International Mobile Telecommunications-2000 (IMT-2000), Recommendation ITU-R

M.687-2, 1997.
DoD IMT-2000 Assessment

D-11

JSC Spherical Earth Model (SEM)16 with the modified free space option. Antenna heights used were 40

m for the IMT-2000 base stations and 9000 m for the airborne receiver. For these antenna heights and

an assumed smooth earth, the radio LOS was calculated to be approximately 260 miles.

The total power at the airborne receiver was calculated using Equation D-1 (Adapted from Reference 6):

I(dBW/Hz) = ∑

=

n

i 1

Pd Pmi Dpl lpi (D-1)

where:

Pd = power density per square kilometer per Hertz generated by IMT-2000 stations in an

urban environment. Given by Reference 15 as 38 μW/km2/Hz

Pmi = population of the ith visible metropolitan area, in millions

Dpl = average inverse population density, in km2 per million

lpi = path loss from the ith metropolitan area, equal to 10-L/10, where L is the path loss from

the JSC SEM, in dB

Values of Pm used were the populations of the Ranally Metropolitan Areas, taken from the Rand

McNally Commercial Atlas and Marketing Guide.17 The values used are population estimates for 1

January 1999.

In Reference 6, the average population density was determined by averaging the population densities of

the metropolitan areas or central cities for eight world cities. The average ratio was calculated to be

144.2 km2/million.

As in Reference 6, a factor for environmental losses, 10 dB, was subtracted from the results of Equation

D-1. Use of a lesser value, such as 0 dB, was also considered.

The results of the calculations using Equation D-1 are given in Tables D-9 and D-10 for Nellis AFB and

Cherry Point, respectively.

 

16 David Eppink and Wolf Kuebler, TIREM/SEM Handbook, ECAC-HDBK-93-076, Annapolis, MD: DoD ECAC, March 1994.

17 Rand McNally & Co., Rand McNally 2000 Commercial Atlas & Marketing Guide, 131st Edition, 2000, pp. 124-125.
DoD IMT-2000 Assessment

D-12

Table D-9. Power Levels from Nearby Cities, Nellis AFB ACMI Range

City Distance

Miles km

Population

(Metro

Area)

(mil.)

Equiv.

Area

(km2

)

Path Loss,

dB

Received

Power

Density

(dBW/Hz)

Las Vegas, NV 58 93 1.2575 181.3 137 -158.6

Los Angeles, CA 260 418.4 13.11 1890.5 169.7 -181.1

Bakers-field, CA 234 376.6 0.404 58.24 149.1 -175.6

Fresno, CA 253 407.1 0.726 104.7 159.7 -183.7

Riverside, CA 234 376.6 1.536 221.5 149.1 -169.8

The total power density is -158.2 dBW/Hz; with a 10-dB factor for environmental losses, it is -168.2

dBW/Hz.

Table D-10. Power Levels from Nearby Cities, Cherry Point MCAS

City Distance

Miles km

Population

(Metro

Area)

(mil.)

Equiv.

Area

(km2

)

Path Loss,

dB

Received

Power

Density

(dBW/Hz)

Richmond, VA 200 322 .861 124.1 147.7 -171.0

Norfolk, VA 140 225 1.006 144.9 144.6 -167.2

Newport News, VA 140 225 0.476 68.6 144.6 -170.4

Fayetteville, NC 135 217 0.319 46.1 144.3 -171.9

Charlotte, NC 240 386 1.215 175.3 149.3 -171.1

Charleston, SC 240 386 0.4782 69.1 149.3 -175.1

Columbia, SC 260 418 0.4924 71.0 169.4 -195.1

Raleigh, NC 140 225 0.6733 97.1 144.6 -168.9

Durham, NC 140 225 0.3273 47.2 144.6 -172.1

The total power was calculated to be -161.4 dBW/Hz; with a 10-dB factor for environmental losses, it is

-171.4 dBW/Hz.

Results of the interference calculations are given in Table D-11 for TACTS/ACMI air-to-ground

separation distances of 35 and 78 km, for the aggregate interfering signal without environmental losses,

the interfering signal with 10 dB losses, and the interfering signal attenuated by 10 dB, with the 10 dB

loss factor. The 10-dB attenuation may approximate a situation where the IMT-2000 system is near the

beginning of its full-scale implementation.

The results in Table D-11 show that the TACTS/ACMI link margins are degraded to -22 to -29 dB, with

the full aggregate interfering signal, with 10 dB of environmental losses. With 10 dB less interfering

power than predicted with the full operational implementation, link margins are still degraded to -12 dB

at the 35 km TACTS/ACMI transmitter-to-receiver separation distance and -19 dB at the 78-km
DoD IMT-2000 Assessment

D-13

separation distance. Since a number of factors could cause the calculated numbers to be higher than

those shown, the results suggest that sharing in a full IMT-2000 environment is not feasible.

Table D-11. TACTS/ACMI Airborne Receiver Link Margins With and Without

IMT-2000 Interference

Aircraft Altitude 9000 m 9000 m

Distance from Ground Transmitter 78 km 35 km

Range Between A/C and Ground

Transmitter

78.52 km 36.14 km

Ground Transmitter Power 7 dBW 7 dBW

Transmit Antenna Gain 0 dBi 0 dBi

Transmitter System Losses 2 dB 2 dB

Transmitter Data Rate (198.4 kb/s) 53.0 dB/Hz 53.0 dB/Hz

Transmit Eb -48 dBW -48 dBW

Free Space Path Loss

(1800 MHz)

135.4 dB 128.7 dB

Airborne Receiver Antenna Gain 0 dBi 0 dBi

Rx Noise (3 dB NF) -201 dBW/Hz -201 dBW/Hz

Eb/No 17.6 dB 24.3 dB

Criterion

(Eb/No for BER = 10-5)

13.35 dB 13.35 dB

Margin (No Interference) 4.2 dB 10.9 dB

Io -158 dBW/Hz -158 dBW/Hz

Eb/(No + Io) -25.4 dB -18.7 dB

Degraded Below Criterion 38.8 dB 32.1 dB

Io -168 dBW/Hz -168 dBW/Hz

Eb/(No + Io) -15.4 dB -8.7 dB

Degraded Below Criterion 28.8 dB 22.1 dB

Io -178 dBW/Hz -178 dBW/Hz

Eb/(No + Io) -5.4 dB 1.3 dB

Degraded Below Criterion 18.8 dB 12.1 dB

Io -188 dBW/Hz -188 dBW/Hz

Eb/(No + Io) 4.6 dB 11.3

Degraded Below Criterion 8.8 dB 2.1 dB

D.4.1.2 Interference from IMT-2000 into TACTS/ACMI Ground-Based Receivers

To analyze interference from IMT-2000 into TACTS/ACMI ground-based receivers, the required

separation distance to preclude interference into a ground receiver from a single IMT-2000 base and

mobile transmitter was calculated. The IMT-2000 parameters used in the calculations are given in

Tables A-4 and A-5. The TACTS/ACMI ground receiver and antenna parameters are given in Tables

D-1, D-2, and D-3.

As was assumed in Reference 6, TACTS/ACMI operations are link-margin limited. The volume of

space usable for flight training is determined by the available link margin. It was assumed that the

maximum range between ground-based and airborne equipment, which determines the maximum

aircraft-to-aircraft separation, cannot be reduced by more than ten percent due to interference from IMT2000 systems. This condition equates to an allowed degradation in the TACTS/ACMI link margin of
DoD IMT-2000 Assessment

D-14

approximately 1 dB and an I/N of –6 dB. It is noted, as in Reference 6, that the full amount of

interference degradation is made available to IMT-2000, rather than only ten percent of the total

interference budget, as is often considered reasonable.

Interference between ground-based transmitters and receivers was calculated using Equation D-2:

I = PT + GT + GR – LP – LS – LSP – FDR (D-2)

where

I = interference power in receiver, in dBm

PT = transmitter power, in dBm

GT = transmitter antenna gain in direction of receiver, in dBi

GR = receiver antenna gain in direction of transmitter, in dBi

LP = propagation loss, in dB

LS = system losses, in dB

LSP = processing loss of interference in a spread spectrum receiver, in dB

FDR = frequency-dependent rejection, in dB.

The interference power I was set to a maximum allowable value, the interference threshold It, which is

set for the TACTS/ACMI receivers at 6 dB below the receiver noise level, and Equation D-2 was

rearranged to form Equation D-3:

LP = PT + GT + GR – LS – LSP – FDR – It (D-3)

where quantities are as previously defined.

The factor LSP, for a direct-sequence spread spectrum receiver such as those used for CDMA versions of

the IMT-2000, is given by Equation D-4:

LSP = 10 log (Rc/Rd) (D-4)

where:

Rc = chip rate of receiver, chips/s

Rd = data rate of system, bits/s.

Frequency-dependent rejection (FDR) for the ontune cases considered here is given by Equation D-5:
DoD IMT-2000 Assessment

D-15

FDR = 10 log (Bt/Br) for Bt > Br

0 for Bt ≤ Br (D-5)

where:

Bt = transmitter 3-dB emission bandwidth, in Hertz

Br = receiver bandwidth, in Hertz.

The receiver bandwidth for use in Equation D-5 was assumed equal to the chip rate, for code division

multiple access (CDMA) IMT-2000 receivers and other direct-sequence spread-spectrum receivers. For

time division multiple access (TDMA) receivers, the receiver bandwidth and bit rate were assumed

equal for this analysis, at 30 kHz for the IS-136 and 176 kHz for the Groupe Speciale Mobile (GSM)

system, and the LSP term is not applicable.

The required separation distance to preclude interference was calculated using the required propagation

loss from Equation D-3 and the JSC Inverse Smooth Earth Model. Antenna heights used were 40 m and

1.5 m for the IMT-2000 base station and mobile transmitters respectively, and 30 m for the

TACTS/ACMI receivers. The required separation distances are given in Table D-12. The distances

shown are the maximum for all versions of the IMT-2000 listed in Tables A-4 and A-5. For one case,

the wideband CDMA, a FDR of 3 dB would lower the separation distances slightly. For the other three

IMT-2000 versions, the FDR is 0 dB. TACTS/ACMI antenna gain values of 26 dBi and 0 dBi were

used. The 26 dBi gain represents either the master or the remote station in a ground-to-ground

interaction. The 0-dBi gain represents the remote station used as a TIS uplink. It is expected that the 3-

dBi gain shown in Table D-3 would be reduced by 3 dB for polarization differences between the righthand circular polarization of the TACTS/ACMI antenna and the linear polarization of the interfering

signal.

Table D-12. Distances, in km, from IMT-2000 Transmitters to Preclude Interference to

TACTS/ACMI Ground-Based Receivers

TACTS/ACMI Antenna Gain IMT-2000 Station

(dBi) Mobile Base

0 20.0 70.1

26 38.9 146.1
DoD IMT-2000 Assessment

D-16

D.4.1.3 Interference from TACTS/ACMI Ground-Based Transmitters into IMT-2000

System

Separation distances to be maintained by IMT-2000 receivers from TACTS/ACMI ground transmitters

to preclude interference were calculated using the path loss from Equation D-3 and the inverse SEM

propagation model. Parameters for the IMT-2000 receivers are taken from Tables A-4 and A-5 and

parameters for the TACTS/ACMI transmitters and antennas were taken from Tables D-1 and D-3. For

the IMT-2000 receiver interference criteria, the two values in Tables A-4 and A-5 were used, plus an

additional, higher value, corresponding to the desired signal 20 dB above the receiver sensitivity level.

It was felt that the two higher thresholds used would represent a range of realistic received signal levels.

Separation distances for each interference threshold and TACTS/ACMI transmitter-antenna combination

are given in Table D-13. For the highest interference threshold, only one value, the worst-case, was

calculated. Distances for the other IMT-2000 versions are expected to be slightly less, as was the case

for the lower thresholds.

For the narrowband TACTS/ACMI signals, the Master Station (MS) and TIS ground-to-ground links,

the separation distances for the CDMA WB and NB IMT-2000 implementations are slightly smaller

than for the TDMA implementation. This is because the CDMA implementations offer some processing

loss to the narrowband TACTS/ACMI signal, due to the correlation of the desired signal and subsequent

narrowband filtering in the receiver. The separation distances for both TDMA implementations were

practically identical.

Table D-13. Distances, in km, from TACTS/ACMI Ground-Based Transmitters to Preclude

Interference to IMT-2000 Receivers

IMT-2000 Station

Mobile Base

TACTS/ACMI Antenna Gain

and Tx Power

CDMA

WB

CDMA

NB

TDMA CDMA

WB

CDMA

NB

TDMA

IMT-2000 Interference Criterion I/N = -6 dB

MS 26 dBi/20 W 46 48.4 50.7 132.1 157.9 180.3

TIS 26 dBi/1 W 38.5 41.3 43.2 85.1 98.4 110

G/A 0 dBi/5 W 25.2 25.9 26 63.2 63.9 64

IMT-2000 Interference Criterion for S = Sensitivity + 10 dB

MS 26 dBi/20 W 36.9 39.8 41.8 80 90.8 101

TIS 26 dBi/1 W 27.9 31.4 33.7 66 69.7 72.5

G/A 0 dBi/5 W 11.9 12.7 12.8 49.2 50.1 50.2

IMT-2000 Interference Criterion for S = Sensitivity + 20 dB

MS 26 dBi/20 W 35.3 74.6

TIS 26 dBi/1 W 26.0 64.3

G/A 0 dBi/5 W 5.7 39.1
DoD IMT-2000 Assessment

D-17

D.4.1.4 Interference from TACTS/ACMI Airborne Transmitters into IMT-2000 System

The required separation distances between an airborne TACTS/ACMI transmitter (at 9000 m altitude)

and IMT-2000 base and mobile stations were calculated in a manner similar to those for the groundbased ACTS transmitters. For each value of required path loss, the JSC inverse smooth-earth

propagation model was used to calculate the required separation distance. For the IMT-2000 base

stations, a 2.5-degree downtilt angle was assumed and a maximum antenna gain, at the horizon or above,

of 5 dBi was used in the analysis. Results of the calculations are shown in Table D-14. Because of the

relatively wide bandwidth of the AIS downlink signal, little processing gain is realized by the CDMA

implementations, and the separation distances for the three versions are not significantly different. The

required separation distances for the base stations approach LOS for the lowest interference threshold,

and they are in the neighborhood of 180 km for the middle interference threshold. These distances could

significantly reduce the area of IMT-2000 usage near TACTS/ACMI training ranges.

Table D-14. Required Separation Distances, in km, to Preclude Interference from TACTS/ACMI

Airborne Transmitters into IMT-2000 Receivers

IMT-2000 Station

Mobile Base

CDMA

WB

CDMA

NB

TDMA CDMA

WB

CDMA

NB

TDMA

IMT-2000 Interference Criterion I/N = -6 dB

318.9 320.1 322.7 404.4 405.4 405.5

IMT-2000 Interference Criterion for S = Sensitivity + 10 dB

57.1 63.5 64.3 162.8 180.6 182.7

IMT-2000 Interference Criterion for S = Sensitivity + 20 dB

14.7 16.9 17.1 47.8 53.2 53.9

D.4.2 JTCTS Technical Assessment

D.4.2.1 Interference from IMT-2000 into JTCTS Airborne Receivers

The JTCTS data link signal structure is 16-ary, orthogonal signaling, with 0.351, 0.703, and 1.406 Mb/s

data rates combined with either 5.63 or 22.5 Mc/s pseudorandom spreading codes. Symbol rates are

89.9, 175.8, and 351.5 kb/s. The required Es/No, including Reed-Solomon forward error-correcting code

gain, is 11.0 dB.

Table D-15 contains the calculations of the JTCTS link margins for the aircraft altitude of 9000 m

(approximately 30,000 feet), and two separation distances, in the absence of interference. The first

separation distance, 78 km, is the same as used in the TACTS/ACMI analysis. The second distance, 150

nmi (277.8 km) represents the specified maximum separation distance for the JTCTS air-to-air link
DoD IMT-2000 Assessment

D-18

(Reference 12), which is its primary communications link. In the absence of interference, link margins

vary, depending on the symbol rate, from 16 to 22 dB for the 78-km distance, and from 5 to 11 dB for

the 278-km distance.

It was assumed that the JTCTS was subjected to the same aggregate IMT-2000 interference levels as

those calculated earlier for the TACTS/ACMI systems. Table D-16 shows the received Es/(No + Io) and

resulting link margins in the presence of the aggregate IMT-2000 RF environment. With Io = -168

dBW/Hz, negative link margins of from –10 to –16 dB result, depending on the data rate, for the 78 km

distance. For the 150 nmi (278 km) separation, the link margins are 11 dB less, from –21 to –27 dB.

For a 10-dB lower aggregate interference level, expected to occur before a mature usage rate is

developed, negative link margins exist for all but the lowest symbol rate (87.9 ksps) at the 78 km

separation, and at all symbol rates at the 278 km separation.

Comparison of the results for the JTCTS and TACTS/ACMI systems show that the JTCTS link margins

are somewhat higher in the presence of interference, than are those of the TACTS/ACMI. However, the

effect is still such that, even with an incomplete buildup of the IMT-2000 environment, operation of the

systems at typical training ranges will be degraded.
DoD IMT-2000 Assessment

D-19

Table D-15. JTCTS Airborne Receiver Link Margins Without IMT-2000 Interference

Aircraft Altitude 9000 m 9000 m

Distance from Tx 78 km 277.8 km (150 nmi)

Transmitter Power 18.3 dBW 18.3 dBW

Transmit Antenna Gain 2 dBi 2 dBi

Tx System Losses 2 dB 2 dB

Transmit Symbol Rate

87.9 ksps 49.5 dBHz 49.5 dBHz

175.8 ksps 52.5 dBHz 52.5 dBHz

351.6 ksps 55.5 dBHz 55.5 dBHz

Transmit Energy per Symbol

87.9 ksps -31.2 dBW -31.2 dBW

175.8 ksps -34.2 dBW -34.2 dBW

351.6 ksps -37.2 dBW -37.2 dBW

Free Space Path Loss (1800 MHz) 135.4 dB 146.4 dB

Airborne Receiver Antenna Gain 2 dBi 2 dBi

Received Es

87.9 ksps -164.6 dBW -175.6 dBW

175.8 ksps -167.6 dBW -178.6 dBW

351.6 ksps -170.6 dBW -181.6 dBW

Rx No (4.5 dB NF) -199.5 dBW/Hz -199.5 dBW/Hz

Es/No

87.9 ksps 34.9 23.9

175.8 ksps 31.9 20.0

351.6 ksps 28.9 17.9

Implementation Losses 2.0 dB 2.0 dB

Required Es/No 11.0 dB 11.0 dB

Margin

87.9 ksps 21.9 dB 10.9 dB

175.8 ksps 18.9 dB 7.9 dB

351.6 ksps 15.9 dB 4.9 dB
DoD IMT-2000 Assessment

D-20

Table D-16. JTCTS Airborne Receiver Link Margins and Degradation Due to IMT-2000

Aircraft Altitude 9000 m 9000 m

Distance from Transmitter 78 km 277.8 km

Received Es/No

87.9 ksps -164.6 dB -175.6 dB

175.8 ksps -167.6 dB -178.6 dB

351.6 ksps -170.6 dB -181.6 dB

Io -158 dBW/Hz -158 dBW/Hz

Es/(No + Io)

87.9 ksps -6.6 dB -17.6 dB

175.8 ksps -9.6 dB -20.6 dB

351.6 ksps -12.6 dB -23.6 dB

Margin

87.9 ksps -19.6 dB -30.6 dB

175.8 ksps -22.6 dB -33.6 dB

351.6 ksps -25.6 dB -36.6 dB

Io -168 dBW/Hz -168 dBW/Hz

Es/(No + Io)

87.9 ksps 3.4 dB -7.6 dB

175.8 ksps 0.4 dB -10.6 dB

351.6 ksps -2.6 dB -13.6 dB

Margin

87.9 ksps -9.6 dB -20.6 dB

175.8 ksps -12.6 dB -23.6 dB

351.6 ksps -15.6 dB -26.6 dB

Io -178 dBW/Hz -178 dBW/Hz

Es/(No + Io)

87.9 ksps 13.4 dB 2.4 dB

175.8 ksps 10.4 dB -0.6 dB

351.6 ksps 7.4 dB -3.6 dB

Margin

87.9 ksps 0.4 dB -10.6 dB

175.8 ksps -2.6 dB -13.6 dB

351.6 ksps -5.6 dB -16.6 dB

Io -188 dBW/Hz -188 dBW/Hz

Es/(No + Io)

87.9 ksps 23.4 dB 12.4 dB

175.8 ksps 20.4 dB 9.4 dB

351.6 ksps 17.4 dB 6.4 dB

Margin

87.9 ksps 10.4 dB -0.6dB

175.8 ksps 7.4 dB -3.6 dB

351.6 ksps 4.4 dB -6.6 dB
DoD IMT-2000 Assessment

D-21

D.4.2.2 Interference from IMT-2000 into JTCTS Ground-Based Receivers

As was done for the TACTS/ACMI, it was assumed for the JTCTS that the maximum range between

ground and air stations (which in turn determines the maximum aircraft-to-aircraft separation) cannot be

reduced by more than about 10 percent due to interference from IMT-2000 systems. This condition

equates to an allowed degradation in the JTCTS link margin of approximately 1 dB and an interferenceto-noise power ratio criterion of –6 dB. It again is noted that the full amount of interference

degradation is made available to IMT-2000, rather than apportioning only 10 percent of the total

interference budget to this system, as is sometimes considered reasonable. Although a high (26 dBi)

antenna gain was not given in the JTCTS system description, it was assumed that an antenna of this type

could be used in a tertiary, or ground-to-ground, link.

All IMT-2000 transmitters considered were narrower in bandwidth than the narrower-bandwidth JTCTS

chip rate. A processing loss equal to the ratio of the chip rate to the data rate was applied to the

interfering signal level, as described earlier. For each chip rate, the separation was the same for each

data rate considered. This is due to the processing loss compensating for the change in noise level. The

processing loss is proportional to the data rate, while the noise power, and hence the interference

threshold, is inversely proportional to the data rate. See Table D-17.

Table D-17. Separation Distances, in km, from JTCTS Ground Receivers to Preclude

Interference from IMT-2000 Transmitters

JTCTS Antenna Gain, IMT-2000 Station

(dBi)

JTCTS

Receiver

Chip Rate

(MChips/

s)

Data Rate, Mb/s

Mobile Base

5.63 0.3516 13.0 65.4

1.406 13.0 65.4

0.3516 8.1 58.7

0

22.5

1.406 8.1 58.7

5.63 0.3516 33.8 117.3

1.406 33.8 117.3

0.3516 29.6 89.5

26

22.5

1.406 29.6 89.5

D.4.2.3 Interference from JTCTS Ground-Based Transmitters into IMT-2000 System

Separation distances which may need to be maintained by IMT-2000 receivers to preclude interference

from JTCTS ground transmitters were calculated in a manner similar to those corresponding distances

for the TACTS/ACMI ground transmitters. The JSC inverse SEM propagation model was used, with

the JTCTS characteristics of Tables D-5 and D-7 and the IMT-2000 characteristics of Tables A-4 and
DoD IMT-2000 Assessment

D-22

A-5. Separation distances were calculated for both the narrowband and wideband JTCTS signal, and

each of the four IMT-2000 variations considered, for both mobile and base stations. Results are given in

Tables D-18 and D-19. In Table D-18, the separation distances for each version of the IMT-2000,

against the wideband JTCTS signal, were the same. In Table D-19, the wideband CDMA version gave

slightly more processing loss to the narrowband JTCTS signal, resulting in slightly smaller separation

distances, when compared to the other versions, whose separation distances were identical.

Table D-18. Distances, in km, from JTCTS Wideband Ground-Based Transmitters to Preclude

Interference to IMT-2000 Receivers

JTCTS Antenna Gain (dBi) IMT-2000 Station

Mobile Base

IMT-2000 Interference Criterion I/N = -6 dB

0 32.1 71.3

12 40.3 93.4

26 48.1 154.2

IMT-2000 Interference Criterion for S = Sensitivity + 10 dB

0 20.8 58.6

12 30.2 68.5

26 39.5 89.2

IMT-2000 Interference Criterion for S = Sensitivity + 20 dB

0 11.7 48.9

12 22.1 60.0

26 32.8 71.4

Table D-19. Distances, in km, from JTCTS Narrowband Ground-Based Transmitters to Preclude

Interference to IMT-2000 Receivers

IMT-2000 Station

Mobile Base

JTCTS Antenna Gain (dBi)

WB CDMA Others WB CDMA Others

IMT-2000 Interference Criterion I/N = -6 dB

0 33.5 35.2 72.3 74.4

12 41.1 42.5 97.1 105.7

26 48.7 50.6 161.7 178.8

IMT-2000 Interference Criterion for S = Sensitivity + 10 dB

0 21.8 23.9 59.6 61.8

12 31.1 32.8 69.4 71.5

26 40.2 41.7 92.5 100.4

IMT-2000 Interference Criterion for S = Sensitivity + 20 dB

0 12.6 14.8 50.0 52.4

12 23.1 25.1 60.9 63.0

26 33.5 35.2 72.3 74.4
DoD IMT-2000 Assessment

D-23

D.4.2.4 Interference from JTCTS Airborne Transmitters into IMT-2000 System

The interference from airborne JTCTS transmitters into IMT-2000 receivers was calculated using the

same approach and path loss model as was done in a preceding section for the TACTS/ACMI system.

As in the preceding section, results are given for both narrowband and wideband JTCTS waveforms.

Results are given in Tables D-20 and D-21. Again, for the wideband JTCTS waveform, distances are

equal for all IMT-2000 versions, while for the narrowband JTCTS waveform, the wideband CDMA

IMT-2000 implementation results in a slightly lower separation distance.

Tables D-20 and D-21 show that the required separation distances are quite high (100 to 400 km), even

for the higher interference thresholds. They are higher than those shown for the TACTS/ACMI

transmitters, primarily because of the higher EIRP of the JTCTS equipment. Depending on the

interference criterion used, coordination to line of sight distances may be necessary to avoid interference

from the airborne system to the IMT-2000 receivers.

Table D-20. Required Separation Distances, in km, to Preclude Interference from JTCTS

Wideband Airborne Transmitters into IMT-2000 Receivers

IMT-2000 Station

Mobile Base

CDMA

WB

CDMA

NB

TDMA CDMA

WB

CDMA

NB

TDMA

IMT-2000 Interference Criterion I/N = -6 dB

343.6 343.6 343.6 415.9 415.9 415.9

IMT-2000 Interference Criterion for S = Sensitivity + 10 dB

187.0 187.0 187.0 399.7 399.7 399.7

IMT-2000 Interference Criterion for S = Sensitivity + 20 dB

55.2 55.2 55.2 157.3 157.3 157.3

Table D-21. Required Separation Distances, in km, to Preclude Interference from JTCTS

Narrowband Airborne Transmitters into IMT-2000 Receivers

IMT-2000 Station

Mobile Base

CDMA

WB

CDMA

NB

TDMA CDMA

WB

CDMA

NB

TDMA

IMT-2000 Interference Criterion I/N = -6 dB

346 351.4 351.4 417 420 420

IMT-2000 Interference Criterion for S = Sensitivity + 10 dB

212 283.7 283.7 400 402 402

IMT-2000 Interference Criterion for S = Sensitivity + 20 dB

62.8 84.1 84.1 179 238 238
DoD IMT-2000 Assessment

D-24

D.4.3 Mitigation Techniques

Possible methods to mitigate interference between IMT-2000 and ACTS equipment include the

following. These techniques were generally found to be not practical or operationally unacceptable.

• Coordination of antenna orientation of IMT-2000 base stations with the location of the training

ranges. The mainbeams of the IMT-2000 antennas should not point in the direction of training

range ground stations or of major flight activity, and the IMT-2000 base stations should not be

illuminated by the mainbeams of high-gain ACTS ground station antennas.

• Coordination of training range aircraft training schedules with IMT-2000 operations, such that

IMT-2000 power levels, frequencies, or antenna orientations could be adjusted to avoid mutual

interference.

• Use of polarization diversity between IMT-2000 base stations and ACTS equipment, to reduce

interference levels for mainbeam-to-mainbeam interactions between IMT-2000 and ACTS

equipment.

D.4.4 Results – Option 1

1. Because of the large separation distances needed to avoid interference from airborne ACTS

transmitters to IMT-2000 receivers, and because of the effect of the aggregate IMT-2000 ground

environment on the link margins of the airborne ACTS receivers, sharing of the two systems, without

frequency separation, does not appear feasible.

2. Interference between airborne ACTS transmitters and IMT-2000 receivers and between the aggregate

IMT-2000 environment and ACTS airborne receivers seem to be the worst, or most limiting, cases, for

band sharing.

3. A 10 dB reduction of aggregate interference power, as might be associated with an incomplete

buildup of a mature IMT-2000 environment, still results in negative link margins for TACTS/ACMI and

JTCTS airborne receivers.

4. For ground-to-ground interactions, separation distances to avoid interference appear to be of the same

order of magnitude for ACTS-to-IMT-2000 and IMT-2000-to-ACTS interactions. Effects on system

operation depend on interference thresholds used and the location of the ACTS ground equipment.
DoD IMT-2000 Assessment

D-25

D.4.5 Operational Impact

Full band sharing of the 1755-1850 MHz spectrum with ACTS and IMT-2000 is not considered to be a

viable option. As reported in the DoD IMT-2000 Technical Working Group Interim Report, the results

of the full band sharing electromagnetic compatibility (EMC) assessment indicates that significant

undesired interactions may occur both to and from ACTS. Distance separations needed to preclude

interference can be substantial, particularly in the case of airborne platforms. Overseas ACTS ranges

experiencing undesired interactions from cellular phone communications confirm this assessment.

Coordination and scheduling of shared spectrum between DoD training ranges and IMT-2000 is not

possible due to mission classification, complex range operations, and allowing immediate support of

unplanned training exercises. Also, training missions continue to require increased range airspace.

Operational limitations and constraints cannot be placed on missions supporting warfighter training.

Spectrum sharing would further negatively impact-training operations by restricting tethered RF

connectivity & operations of ACTS pods with the range ground system infrastructure. It would also

restrict available range airspace, which negatively affects training in the use of simulated munitions

systems. It limits training mission scheduling and live monitoring capabilities. It would constrain

ACTS interoperability and compatibility. Sharing would limit or preclude large-scale joint training

exercises and limit migration to rangeless air-to-air operational training.

Under the program of record, JTCTS will not be deployed in CONUS by 2003. It is anticipated that

under full band sharing in this time frame, all current TACTS/ACMI would be forced to cease operation.

The absence of instrumentation to support live tactical training would result in direct loss of readiness

for combat forces. The ability to observe, evaluate, and provide feedback for complex, multi-faceted

training exercises would be virtually eliminated. Losing the instrumentation capabilities would remove

the source of objective information. Lack of simulation capabilities would negate the ability to

determine force attrition in real-time for realistic evaluation of tactics and tactical execution.

Under current plans the replacement of legacy TACTS/ACMI by JTCTS will not begin until post 2006

although fixed range development will be ongoing. In the 2006 time frame some data link modifications

could be made, and if started soon enough, an acceleration of the program to replace the legacy

TACTS/ACMI could make significant progress by 2006—but complete conversion of legacy systems by

that time frame is not considered achievable. However, even with a conversion to JTCTS, there are no

mitigation techniques that could be implemented in either JTCTS, legacy TACTS/ACMI, or IMT-2000

in the same geographic region.
DoD IMT-2000 Assessment

D-26

D.5 OPTION 2 – BAND SEGMENTATION/PARTIAL BAND SHARING

The analysis described in the previous sections assumed no separation in frequency between the IMT2000 and ACTS systems. If the present band is segmented, with separate but adjacent segments

allocated separately to ACTS and IMT-2000 systems, the effect of frequency separation between the

two systems becomes of importance.

Two proposed methods for operating within the 1755 to 1850 MHz band were examined briefly, and the

feasibility of satisfactory operation of the ACTS and IMT-2000 equipment was assessed.

In the first plan (Option 2A), the 1755-1805 MHz portion of the band remains allocated to ACTS. The

rest of the band is allocated to IMT-2000 systems. In the second plan (Option 2B), ACTS and IMT2000 are allowed to operate in the present band. The ACTS systems operate as they presently do, and

the IMT-2000 systems must operate in the 1755-1790 MHz portion of the band and coordinate in the

areas where ACTS operates and where interference is a possibility. The 1790-1850 MHz portion of the

band is retained for use by ACTS systems.

D.5.1 Option 2A – 1755-1805 MHz Retained

D.5.1.1 TACTS/ACMI Technical Assessment

Under plan 1 (Option 2A), the TACTS/ACMI would lose six of the 11 frequencies now available to it

across the 1768 to 1840 MHz range. It would lose use of the 1840 MHz (A) or 1830 MHz (B) groundto-air link transmit frequencies, and four of the six frequencies (1807, 1812, 1817, and 1822 MHz) used

for transmitting from the remote ground transmitters to the master receiver. Typically, the

TACTS/ACMI uses eight or more frequencies for its necessary functions. Loss of all but the 1755-1805

MHz portion of the band does not appear feasible for satisfactory operation of the present

TACTS/ACMI system.

A short EMC analysis to determine the feasibility of modifying the TACTS/ACMI to operate in the

1755-1805 MHz band was performed. Minimum frequency and distance separations such that an

interference threshold was not exceeded were calculated. The interference thresholds used were the

same as those in the sharing analysis. The minimum frequency separation to avoid interference between

adjacent ranges was calculated to be 5 MHz, for the AIS transmitter and TIS downlink receiver. It was

also determined that a frequency separation of 4.8 MHz from the band edge is necessary to avoid
DoD IMT-2000 Assessment

D-27

interference from the AIS transmitter to IMT-2000 base station receivers at the band edge, with no

distance constraints.

Frequency and distance separation constraints are expected to be similar between the AIS transmitter

and remote ground receivers, as between the A/G downlink transmitter and G/A downlink receiver.

It is assumed that the master station transmitter frequency is 3 MHz from the band edge, and the "B"

downlink frequency is 5 MHz removed from that. Further, the "A" uplink frequency is assumed to be 5

MHz removed from the upper band edge, with the remote transmitter frequencies at least 5 MHz from

the uplink or downlink frequencies. With these assumptions, the frequency plan of Table D-22 is

possible.

Table D-22. Possible TACTS/ACMI Frequency Plan for 1755-1805 MHz

Frequency, MHz Link Description

1758 Master to Remotes

1763 AIS-to-Remote Downlink "B"

1768 AIS-to-Remote Downlink "A"

1773 Remote-to-Master 1

1778 Remote-to-Master 2

1783 Remote-to-Master 3

1788 Remote-to-Master 4

1795 Remote-to-AIS Uplink B

1800 Remote-to-AIS Uplink A

Using the arrangement of Table D-22, four remote G/G frequencies are available, compared to the six

presently used. The possibility of compressing six G/G frequencies into the 27 MHz of available

spectrum between the downlink "A" and uplink "B" frequencies was not analyzed. Also, a more

detailed EMC analysis of the TACTS/ACMI components should be conducted. The frequency

separation between collocated AIS transmitters and receivers is reduced from 52 MHz to 32 MHz. A

4 dB increase in transmitter-to-receiver isolation from that now employed, to compensate for decreased

rejection due to offtuning, would be necessary.

Without modification of the TACTS/ACMI emission bandwidth or receiver selectivity characteristics,

the electromagnetic interference (EMI) margin of the modified system will be reduced from that of the

present system. A major modification of the TACTS/ACMI, such as using GPS for position

determination, would allow the bandwidths of the air-to-ground (A/G) and ground-to-air (G/A) signals

to be reduced from 3 MHz to a value closer to the present data rate, 198 kHz. Thereby, the amount of
DoD IMT-2000 Assessment

D-28

spectrum needed would be reduced further. Also, since multilateration is no longer needed, the number

of ground-to-ground (G/G) frequencies would be reduced from the six presently used to one or two.

D.5.1.2 JTCTS Technical Assessment

The JTCTS normally uses one to three frequencies between 1710 and 1850 MHz. This range is further

restricted to 1755-1850 MHz in the US and Possessions. One frequency is used for air-to-air

communications, the primary link. A second frequency is often used for the secondary link, for groundto-air communications. The third frequency is used for a tertiary data link for ground to ground

communications. This link is not always used.

In conversations with JTCTS engineers at SRI International, it has been stated that it may be possible for

the JTCTS to operate with two 22.5 MHz channels separated by 5 MHz at the –20 dB points of the

spectrum. The total occupied bandwidth for the wideband mode would be approximately 22.5 x 2 + 5 =

50 MHz. The third frequency, for the tertiary link, could be reassigned to a different, probably a higher,

band. It may be possible that the two channels can operate without mutual interference, as has been

stated. However, the effect of JTCTS interactions with IMT-2000 equipment near the edges of the band

must also be investigated. A preliminary assessment of the effects of frequency separation was made by

generating frequency-distance curves for JTCTS-to-IMT-2000 and IMT-2000-to-JTCTS interactions.

The curves generated are for wideband CDMA and wideband JTCTS versions. The middle CDMA

interference threshold was used, corresponding to a desired signal 10 dB above sensitivity. These

curves are given as Figures D-2 and D-3. Although conservative interference thresholds were used in

generating these curves, they show that, at the band edges, 11.25 MHz from the JTCTS wideband center

frequency, significant separation distances are needed to avoid interference. Further investigations of

these interactions would be necessary to determine the feasibility of this band segmenting plan.
DoD IMT-2000 Assessment

D-29

F-D CURVE-JTCTS AIR TO IM T-2000 BASE 

0

5 0

100

150

200

250

300

350

400

450

0 5 10 15 20 25 30

Frequency Separation, M H z

Distance, km

-

Figure D-2. Frequency-Distance Curve for JTCTS Airborne to IMT-2000 Interaction

F-D CURVE-IMT-2000 BASE TO JTCTS AIR

0

50

100

150

200

250

300

350

400

450

0 10 20 30 40 50 60 70 80 90

Frequency Separation, MHz

Distance, km

Figure D-3. Frequency-Distance Curve for IMT-2000 to JTCTS Airborne Interaction
DoD IMT-2000 Assessment

D-30

D.5.1.3 Operational Impact

Interference with the ACTS data link will occur dependent on frequency, location, and transmitter power

of future IMT-2000 equipment. The RF interference will adversely affect system operation.

Interference with uplink frequencies (1830 and 1840 MHz) will render ACTS airborne instrumentation

inoperative while interference with ACTS ground-to-ground RF links could vary with portions of the

range becoming inoperative. Additionally, there is no current way to limit system operation to a portion

of the band, therefore it must be assumed ACTS operation will adversely affect IMT-2000 systems.

This would likely cause severe restrictions to TACTS/ACMI emissions thus significantly reducing

system utility.

If the ACTS loses access to the 1805-1850 MHz band in 2006, the impacts would be similar to those

described for 2003 unless modification to the existing frequency plan is pursued. A remanufacture of

existing TACTS/ACMI hardware (updating for obsolescence and technology advances) could make

operation of the legacy systems within a reduced bandwidth feasible. It is estimated the fielding of the

proposed ACTS modifications could be accomplished for all ranges by 2006. However, operational

training will be impacted because of range downtime during installation and checkout of the

modifications. Each range will be completely down for at least 1-3 months with limited capability up to

6 months due to modification of range equipment. A moderate schedule risk is assessed in modifying all

the ACTS ranges by 2006. For 2010, the assessment is the same as the assessment for provided 2006

except that risk is reduced based on additional time to deploy.

The operational impact can be minimized if no spectrum conflicts arise with other Government systems

and all the mitigation efforts are completely implemented by 2006 (schedule risk) or if turnover of

1805-1850 MHz band can be delayed at sites where mitigation measures have not been completed by

2006.

The replacement of the legacy ACTS by JTCTS is scheduled to begin after 2006. The 2010 time frame

may allow for an accelerated JTCTS program to provide replacement ACTS, provided actions are taken

sufficiently early. A modification program for the legacy ACTS could also be completed by that time

frame—but that would be moot if all systems have been replaced by JTCTS. Any loss of current system

use or functionality would impact the training and readiness of the aircrews, with the impact directly

related to the historical tactical training role/function of the system at a given site.
DoD IMT-2000 Assessment

D-31

D.5.2 Option 2B – Phased Segmentation to 1790-1850 MHz Retained

D.5.2.1 TACTS/ACMI Technical Assessment

In Option 2B, which involves coordination within the same band, IMT-2000 systems would be forced to

coordinate their operation in areas where present ACTS systems operate and interference is a possibility.

In the first segment of the band to be made available, 1710 to 1755 MHz, no TACTS/ACMI frequencies

exist, and JTCTS does not normally operate in this range in the US and Possessions. For the other

segments (1755 to 1780 and 1780 to 1790 MHz), airborne and ground-based TACTS/ACMI frequencies

are used. The results of the previous sharing analysis show that, for the airborne ACTS transmitters,

coordination distances to avoid interference to an IMT-2000 receiver are sometimes at line-of-sight

distances (400 km for 9000 m altitude). Distances needed to avoid interference from aggregate IMT2000 environments to an airborne ACTS receiver are more difficult to calculate. However, with a single

metropolitan area the size of Las Vegas, NV, and ignoring the effects of other cities, preliminary

calculations indicate that separation distances of the same magnitude or larger may be needed.

The possibility of modifying the TACTS/ACMI such that all frequencies, A/G, G/A, and G/G, are

within the 1790-1850 MHz band, and sharing is not necessary, was also considered. The analysis,

results, and frequency plan described in Section 5.1.2.1 apply to this case also, with one exception. That

is, the amount of spectrum available between the downlink "A" and uplink "B" frequencies, for remote

(G/G) links, is increased from 27 to 37 MHz. Allowing 10 MHz for protection between G/G and A/G or

G/A links, 27 MHz are left. This amount of spectrum allows for six G/G frequencies separated by

5 MHz, which is the present arrangement. The frequency separation between collocated AIS

transmitters and receivers is reduced from 52 to 42 MHz. A 2 dB increase in transmitter-to-receiver

isolation, to compensate for decreased rejection due to offtuning, would be necessary. As with the

1755-1805 MHz band the EMI margin would be reduced when compared to that of the present system,

with the present emission bandwidth and receiver characteristics. Further modification of the

TACTS/ACMI, to provide position determination by GPS, would reduce the bandwidth of the A/G and

G/A emissions, and greatly reduce the number of G/G frequencies needed.

D.5.2.2 JTCTS Technical Assessment

Although JTCTS is capable of operating in the first part of the band to be shared in this option, 1710-

1755 MHz, it does not normally operate in this segment in the US and Possessions. For the rest of the

proposed shared band, 1755 to 1780 and 1780 to 1790 MHz, separation distances needed to avoid

interference from the airborne JTCTS and IMT-2000 receivers, as well as from an aggregate
DoD IMT-2000 Assessment

D-32

environment of IMT-2000 transmitters to the JTCTS receiver, are estimated to approach line of sight

magnitudes. Operation in the 1790-1850 MHz band, the part left unshared, would allow at most two of

the three data links to operate compatibly.

D.5.2.3 Operational Impact

Under this option, if IMT 2000 build out is contained below 1755 MHz until perhaps the 2006 time

frame, there would be little impact to DoD operations during that time as ACTS frequencies begin above

1755 MHz. As IMT 2000 equipment is deployed to use frequencies above 1755 MHz, impacts to

TACTS/ACMI would occur. Under the program of record, the replacement of the legacy

TACTS/ACMI by JTCTS will not yet have begun in 2006 although fixed range development will be

ongoing. The 2006 time frame may allow for the replacement of legacy TACTS/ACMI only by a

drastically accelerated JTCTS program, but the schedule realism for replacement of all legacy

TACTS/ACMI by either the current JTCTS or a modified JTCTS in that time frame is questionable. If

started soon enough, a simple modification program for the legacy TACTS/ACMI could allow it to keep

operating in 1780-1850 MHz band. This would allow sufficient time (i.e., until 2010) for all legacy

TACTS/ACMI to be replaced by JTCTS. The ground-to-ground microwave links can be relocated once

suitable spectrum is identified. Operational impact is none if no spectrum conflicts arise with other

Government systems and all the mitigation efforts are completely implemented by 2006 (schedule risk)

or if turnover of 1755-1780 MHz band can be delayed at sites where mitigation measures have not been

completed by 2006. Any loss of current system use or functionality would impact the training and

readiness of the aircrews, with the impact directly related to the historical tactical training role/function

of the system at a given site.

The replacement of the legacy ACTS by JTCTS is scheduled to begin after 2006. The 2010 time frame

may allow for an accelerated JTCTS program to provide replacement of ACTS, provided actions are

taken sufficiently early. A modification program for the legacy ACTS could also be completed by that

time frame—but that would be moot if all systems have been replaced by JTCTS. Any loss of current

system use or functionality would impact the training and readiness of the aircrews, with the impact

directly related to the historical tactical training role/function of the system at a given site.

D.5.3 Results – Option 2

1. Of the band-segmenting plans proposed, plan 1 (Option 2A) involves use of only the

1755-1805 MHz portion of the band. Operation of the present TACTS/ACMI does not appear feasible

with this plan. Operation of a modified TACTS/ACMI may be feasible, with a reduced number of G/A
DoD IMT-2000 Assessment

D-33

link frequencies and/or reduced EMI margin. Further, modification of TACTS /ACMI to use GPS for

position determination would greatly reduce the number of required G/G frequencies. Operation of the

JTCTS may be possible with reassignment of one of the three channels. Interactions of JTCTS with

IMT-2000 equipment in adjacent bands need to be investigated further before feasibility of this option

can be demonstrated.

2. Segmentation plan 2 (Option 2B) involves coordination of IMT-2000 operations in regions where

ACTS systems presently operate and interference is possible. For the portions of the band above

1755 MHz, preliminary analysis, as discussed in this report, indicates that, because of the use of airborne

ACTS transmitters and receivers, coordination distances from flight areas may exceed 400 km, making

partial band sharing with this plan difficult to implement. Operation of a TACTS/ACMI modified such

that all frequencies are within the 1790-1850 MHz band may be feasible, with a somewhat reduced EMI

margin, or with position determination using GPS.

3. Interference problems exist in implementing both segmenting Options 2A and 2B, with the present

TACTS/ACMI. With Option 2A, operation of the present TACTS/ACMI is not feasible. With Option

2B, partial band sharing with the present TACTS/ACMI would lead to required separation distances

approaching radio line-of-sight. Modifications of TACTS/ACMI may make operation in the restricted

bands feasible, for both Options 2A and 2B. For both Options 2A and 2B, operation of JTCTS, with the

tertiary data link assigned to a different band, may be feasible. However, further investigation is needed

to verify this conclusion.

D.6 OPTION 3 – PARTIAL BAND SEGMENTATION/OTHER BAND

COMBINATION

D.6.1 Technical Assessment

In the analysis described here, the effects of loss of part of the 1755-1850 MHz band are treated.

Operation is permitted for ACTS in the 1755-1805 MHz (or 1790-1850 MHz) portion of the band, while

the remainder of the band is reallocated to IMT-2000 use. The focus of this analysis was on the 1755-

1805 MHz portion of the band. Both the 1755-1805 and 1790-1850 MHz portions of the band are in the

frequency ranges of the TACTS/ACMI and JTCTS. Although the 1790-1850 MHz portion is 10 MHz

larger than the 1755-1805 MHz portion considered, most of the conclusions should be generally

applicable to both plans. The ground-to-air (G/A), air-to-ground (A/G), and air-to-air (A/A) links are

assumed to remain in the 1755-1805 (or 1790-1850) MHz band, while the ground-to-ground (G/G) links

of each system are moved in frequency to higher bands. The two bands considered for G/G fixed point-
DoD IMT-2000 Assessment

D-34

to-point communication are 4400-4940 MHz and 7250-8400 MHz. Feasibility, self-interference, and

interference to and from incumbent systems in the band were considered.

D.6.1.1 TACTS/ACMI

D.6.1.1.1 SELF-COMPATIBILITY ANALYSIS

For each system, the reduced available bandwidth means not only that components of the system must

be reassigned to another band, but also that the frequency separations between those components

remaining in the band are reduced. In both the TACTS/ACMI and JTCTS systems at present, the A/G

and G/A (or A/A) link frequencies are generally near the band edge, with G/G link frequencies in the

gap between the two sets. Under the proposed partial segmenting plan, the frequency gap is removed

and the A/G, G/A, and/or A/A links are much closer together. This situation increases the potential for

interference, both within the collocated transceivers and between adjacent ranges.

The TACTS/ACMI A/G and G/A links presently use four frequencies in the 1755-1850 MHz range.

The two uplink frequencies (1840 MHz and 1830 MHz) are called A and B frequencies, respectively,

and are separated by 10 MHz to avoid mutual interference problems at adjoining training ranges. The

two downlink frequencies, 1788 and 1778 MHz, are also A and B frequencies, and are separated for the

same reason. The transmit and receive frequencies are separated by 52 MHz to allow for isolation

between the collocated airborne or ground-based transmitter and receiver.

The feasibility of using a set of four frequencies with reduced separation to fit within the 1755-1805

MHz band was investigated. A frequency plan for the 50-MHz band segment was proposed for study.

The G/A frequencies are 1763 MHz (B) and 1773 MHz (A) and the A/G frequencies are 1787 MHz (B)

and 1797 MHz (A). The 10-MHz frequency separation between B and A frequencies is preserved, the

separation between transmitter and receiver frequencies is reduced from 52 to 24 MHz, and the

separation from band edges is reduced from 15 to 8 MHz.

Frequency Separations Needed for Adjacent Ranges. Calculations of necessary frequency

and distance separation to avoid interference were made. For the AIS transmitter and TIS receiver, it

was found that 5 MHz separation is needed between adjacent ranges, to avoid the necessity of a

specified distance separation.

Frequency Separation or Isolation Needed for Simultaneous A/G and G/A

Communication. For the collocated transmitter and receiver, airborne or ground-based, with the
DoD IMT-2000 Assessment

D-35

52-MHz separation used at present, a rejection of 82.3 dB due to off-tuning was calculated. An

additional 77.7 dB of isolation is needed to avoid interference. Reducing the frequency separation to 24

MHz leads to a 76 dB value of FDR, or a 84 dB loss needed from other isolation. This value is 6.3 dB

more than that attained at present. If TACTS/ACMI were redesigned to use GPS for position

determination, the bandwidths of the A/G and G/A signals could be reduced from 3 MHz to a value

closer to that of the present data rate, 198 kHz, and further reduce the amount of spectrum needed in the

reduced band.

Analysis of System EMI at Band Edges with IMT-2000 Equipment. For the TACTS/ACMI

AIS transmitter, a frequency separation of 4.8 MHz from the band edge is necessary for no distance

constraints to avoid interference to IMT-2000 base station receivers at the band edge. Again the IMT2000 interference threshold assumes the desired signal is 10 dB above the sensitivity level. The

frequency plan for the TACTS/ACMI in the 1755-1805 MHz band, postulated earlier, assumes an

8-MHz frequency separation from the edge of the band. Hence the interference is below the IMT-2000

threshold.

Analysis of EMC with Other Systems in the 1755-1850 MHz or 1790-1850 MHz Band. The

1755-1850 MHz band is currently shared by TACTS/ACMI with tactical radio relay links and missile

video and control links. Reduction of the available spectrum from 95 MHz to 50 (or 60) MHz means,

for the TACTS/ACMI systems, that the G/G links would migrate to other bands. The A/G, and G/A

links, because one or both ends are on an aircraft at an altitude that may reach 30,000 feet or more, may

cause or suffer interference out to distances approaching radio line of sight (390 km at 30,000 ft.). EMC

of the TACTS/ACMI with itself is difficult to attain in this band, especially when adjacent ranges are

considered. For the JTCTS, self-compatibility, when adjacent ranges are considered, has not been

predicted to be attainable through frequency separation alone. For the TACTS/ACMI, although EMC

with itself is predicted to be attainable, interference from or to other systems in this band, such as

tactical radio and missile control links, would add to a compatibility situation that is marginal at best.

D.6.1.1.2 Issues of Moving Ground-to-Ground Links to Other Bands

Issues of moving G/G links to higher bands are similar for both TACTS/ACMI and JTCTS. The

exception to this rule is that TACTS/ACMI uses a large number, up to 20 or more, of ground-to-ground

links to provide position location by multilateration, while JTCTS uses only one ground-to-ground link

to transmit data to the control station for monitoring or other purposes. The main part of the analysis

will be included under the TACTS/ACMI section, with exceptions to the conclusions noted for JTCTS.
DoD IMT-2000 Assessment

D-36

Issues associated with moving the ground-to-ground links of the TACTS/ACMI and JTCTS to other

frequency bands include feasibility, e.g., propagation phenomena and hardware issues that may affect

link redesign, and potential EMC problems with equipment presently in the band of concern. These

issues were explored for the 4400-4940 MHz and 7250-8400 MHz bands.

Feasibility Assessment—Fade Margin and Link Length. An approximation of the relationship

between link reliability, fade margin, link length, and frequency is given by Equation D-6:18

Undp = a b (2.5 x 10-6) f D3 10-F/10 (D-6)

Where:

Undp = annual outage probability (1 - reliability)

a = terrain factor

b = climate factor

F = fade margin, to the "minimum acceptable" point, in dB

D = path length, in miles

f = frequency, in GHz

The product of a and b equals 0.25, for a normal or average path.

A previous Electromagnetic Compatibility Analysis Center (ECAC) report dealt with site selection of

proposed ACMI facilities at Holloman AFB, NM.19 The length of the master-to-remote paths varies

from 8 to 50 km (5 to 31 mi). For a 50 km (31 mi) path, and a link reliability of 99.99 percent (Undp =

0.0001), use of Equation D-6 results in a 25.3 dB fade margin needed for 1.8 GHz. To preserve the

same link reliability with the same fade margin at 4.4 GHz, the link length would have to be reduced

from 50 km to 36.6 km (22.75 mi). To retain the same link length, and hence the same tower sites, the

fade margin would have to be increased to 29 dB. As an example, increasing the fade margin could be

accomplished by increasing the effective radiated power output by 3.7 dB, or more than doubling the

power.

To operate in the 7.25-8.4 GHz band, use of Equation D-6 shows that a 50 km link would have to be

reduced to 30.8 km (19.1 mi) to preserve a 99.99 percent link reliability with a 25.3 dB fade margin, as

 18 GTE Lenkurt Incorporated, Engineering Considerations for Microwave Communications Systems, San Carlos, CA, 1975, pp. 59-

60.

19 John Covert, ACMI Siting and EMC Study for Holloman Air Force Base, ECAC-CR-79-007, Annapolis, MD: DoD ECAC,

January 1979.
DoD IMT-2000 Assessment

D-37

predicted to occur at 1.8 GHz. To retain the same link length, the fade margin would have to be

increased from 25.3 dB to 31.7 dB. As an example, increasing the fade margin could be accomplished

by increasing the effective radiated power, by about 6 dB, or a factor of x4.

Feasibility Assessment—Power, Noise Figure, and Antenna Gain Considerations. The

TACTS/ACMI TIS remotes use transmitters with 1 to 5 watts (30-37 dBm) of power. Transmitter

powers in this range appear to be readily available throughout the frequency ranges from 1 to 8 GHz.20

If the link lengths were kept the same and the fade margin increased, say, to 29 dB as calculated above,

this would be an increase of 4 dB. A total of 20 log (4800/1800) = 8.5 dB of additional path loss would

be expected. The antenna gain for a parabolic antenna of a given size would increase by 8.5 dB also.

Use of matching high-gain antennas on each end of the link could increase the total coupling gain by

8.5 dB, so the transmitter power would not need to be increased.

The TACTS/ACMI receivers at 1.8 GHz have noise figures in the order of 2-3 dB. While Reference 20

shows a number of available receivers with noise figures in that range at 2 GHz, they are much less

common at higher frequencies. At 4 GHz, they range from 5 to 8 dB, and at 8 GHz, from 8 to 8.5 dB.

More recent manufacturers' data, however, shows that low-noise amplifiers with noise figures less than

2 dB are readily available, at least in commercial versions, for frequencies at and above 10 GHz.21

To provide the increased fade margin needed, an increase of 6.4 dB in received power would be needed.

At the higher frequency, an increase in 12.7 dB in antenna gain could be realized for a given antenna

size. If matching antennas were used on each end of the link, the coupling loss would be decreased by

this amount, making up for the necessary 6.4 dB increase in received power to attain the same link

reliability. As was stated previously, amplifiers with noise figures less than or equal to the 2.3 dB

known to be used by the TACTS/ACMI systems should be readily available.

Self-Interference Potential. Issues associated with interference between the ACTS links should be

no different than for their present configuration. With the TACTS/ACMI, the problem at certain ranges,

such as Fallon, which lists 23 links,22 using six frequencies among them, is expected to be severe but

apparently tractable. If more bandwidth is available, however, the resulting increase in frequency

resources would lessen the problem. A proposed modification to TACTS/ACMI, to use GPS for

 20 MSN Microwave Radio System Matrix, Microwave Systems News, June 1980, pp. 92-108.

21 Manufacturers Data from JCA Technology and MITEQ, Microwaves & RF, September 2000.

22 Mike Ryan, Mid-Atlantic Area Frequency Coordination Office, Naval Air Warfare Center Aircraft Division, facsimile to Bob

Martin and Al Baker, JSC/IITRI, , Patuxent River, MD, October 2000.
DoD IMT-2000 Assessment

D-38

position determination, would also reduce the number of links to one, eliminating the potential for selfinterference.

Self-interference potential in the 7250-8400 MHz band should be similar to that described for the 4400-

4940 MHz band. Because the band is larger (1150 MHz) than at 4400 MHz (540 MHz) more frequency

resources may be available than at the lower band, as well as in the present 95-MHz band

(1755-1850 MHz).

EMC with Incumbent Equipment—4400-4940 MHz. The AN/TRC-170 and AN/GRC-222 are

tactical radios used in both line-of-sight (LOS) and troposcatter modes. They use high-gain antennas,

and compatibility of the ACTS fixed G/G links with these systems should be attainable using a

combination of frequency and distance separation and antenna pointing discrimination.

 The Light Airborne Multipurpose System (LAMPS) is operated primarily in an ocean environment and

is not expected to interact with G/G links at training ranges under most conditions. For CEC, band

sharing is not possible between CEC and the relocated ground-to-ground links that support an air

combat training system for sites where both systems operate simultaneously. Band segmentation would,

among other things, preclude fully integrated training with an attendant and unacceptable reduction in

readiness.

Other equipment in the 4400-4940 MHz range includes threat simulators, which are assigned

frequencies in the 4900-4990 MHz range at the Naval Air Station (NAS) Oceana training range

(Reference 22). In selecting operating frequencies for the ACTS G/G links, the part of this segment

overlapping the 4400-4940 MHz frequency range would need to be avoided.

EMC with Incumbent Equipment—7250-8400 MHz. Equipment presently in this band includes

point-to-point communications links, and earth-to-space and space-to-earth communications links.

According to Reference 22, a number of frequency assignments associated with US Navy training

ranges are in this band. These assignments include those for threat simulators at NAS Oceana (7800-

8500 MHz) and MCAS Yuma (7950-8020 MHz). A number of microwave links are also operating at

frequencies throughout the 7250-8400 MHz range. Frequency assignments for these links include five

at Cherry Point, 15 at Camp Lejeune, and nine at Fallon. EMC with these existing threat simulators and

any associated airborne jammers, as well as with the existing point-to-point links at the three bases

mentioned would have to be considered. Since a number of bands appear to be used for these point-topoint links at different ranges, it may be feasible to reassign the existing point-to-point links to a band

higher than 7250-8400 MHz, in order to effect common TACTS/ACMI or JTCTS frequencies.
DoD IMT-2000 Assessment

D-39

D.6.1.2 JTCTS

D.6.1.2.1 Self-Compatibility Analysis

The present JTCTS, when the maximum number of frequencies are used, consists of three links, the

primary channel, or air-to-air link, the secondary channel, or ground-to-air link, and the tertiary channel,

or ground-to-ground link. Each channel can be tuned to a center frequency between 1710 MHz and

1850 MHz (in 5-MHz increments) (In the US and possessions, the frequency range of operation is

1755-1850 MHz.) However, an example of spectrum usage that has been proposed has the primary and

secondary channels near each edge of the range, with the tertiary channel frequency between the other

two (Reference 11). With a 50-MHz frequency range available, the tertiary channel will be reassigned

to another band, and it has been proposed that the remaining channels will be assigned so that their -20

dB emission levels are at the band edges. For the JTCTS wideband mode, the -20 dB points are at

11.25 MHz from the center frequencies. Therefore, the center frequencies of the primary and secondary

links will be separated by 27.5 MHz. The analysis in this section was conducted assuming the JTCTS

wideband mode was used.

Provisions for Adjacent Ranges. Calculations were made of the distance separations necessary to

avoid interference, for the JTCTS G/A transmitter to the JTCTS air-to-air receiver, with a 27.5 MHz

separation between frequencies. The interference threshold used was an interference-to-noise ratio of

-6 dB, which leads to a 10 percent decrease in maximum communications range. This frequency

separation allows the transmitter spectrums for both transmitters to be 20 dB down at the edge of the

1755-1805-MHz band. With this frequency separation, 76 km distance separation is needed to avoid

interference. The same distance separation applies to the cases of an airborne transmitter and a ground

based receiver, and to an airborne transmitter to an airborne receiver. A frequency separation of

35 MHz is necessary to lower the distance to 20 km. The above distance assumed all transmitters used

the high-power wideband mode of JTCTS. If the low-power mode is used, the separation distance at

27.5 MHz frequency separation is lowered to 25 km, and a 28.4 MHz frequency separation is needed at

20 km.

Several TACTS/ACMI ranges on the east coast are approximately 100 nmi (185 km) apart and use

alternating A and B frequency sets.23 At 185 km a 22.8 MHz frequency separation is necessary, to avoid

interference between two JTCTS systems. While this separation would allow two air-to-air links in the

same band, interference to the ground-to-air links of the adjacent range, if present, would occur.

 23 James C. Hodges, Frequency Management and Avoidance of Mutual Interference Between the TACTS and ACMI Ranges in the

Eastern United States, SRI International, 12 December 1983.
DoD IMT-2000 Assessment

D-40

Frequency separation between adjacent ranges is not practical if both primary (A/A) and secondary

(G/A) links occupy the same band.

Two other ideas are being explored for using JTCTS at adjacent ranges.24 They are: using different

spreading codes that are nearly orthogonal to provide additional isolation, and using timing

discrimination between adjacent ranges, where combined usage of the two ranges does not exceed the

maximum capacity of the system.

If it is possible to control the relative timing of the transmitted signals, the coded signals can be made

nearly orthogonal, the effect of the added signal will be minimal, and only the noise added by the

channel will be significant.25 It may be possible to control this relative timing in cases where two ranges

have access to a common control center, as is the case for the present two-master-station Charleston

TACTS range (Reference 23). However, most adjacent ranges do not at present operate with common

control elements. If the timing between two adjacent ranges is not controlled, the interfering signal will

appear to be noiselike. It will be equivalent to that analyzed in this study, and will be subject to the

same frequency and distance constraints to avoid interference. The presence of dispersion due to

multipath also degrades the orthogonality and increases the noise-like nature of the interfering signal.

The second technique mentioned requires timing discrimination at adjacent ranges and also assumes that

the combined usage of the two ranges would not exceed the total capacity of the system (100 aircraft).

For example, it is not envisioned that either the Yuma or Goldwater ranges would ever use more than 50

aircraft each during a training operation (Reference 24). The time-division multiple access scheme

would provide enough time slots for aircraft in the two ranges. They could conceivably be run as one

range (all on the same primary frequency) with a subset of data being routed to each. This technique

would depend on the ability to coordinate the timing between the two ranges. A detailed examination of

the feasibility of timing coordination was not conducted in this study.

Frequency Separation or Isolation Needed for Simultaneous A/A and G/A

Communication. For the high-power transmitter situation, a 76-km separation in distance is needed

to avoid interference at a 27.5 MHz frequency separation from the G/A transmitter to the A/A receiver,

or from the A/A transmitter to a ground-based receiver. If operation in the low-power mode is used, as

is presently being suggested for the secondary link (Reference 24), the necessary distance separation is

 24 David Hanz, SRI International, e-mail to Allan Baker, JSC/DWD, Re: Additional Questions on JTCTS, Menlo Park, CA, 6

December 2000.

25 B. Paris, "Access Methods," Chapter 79 of J. Gibson, ed., The Communications Handbook, IEEE Press, 1999.
DoD IMT-2000 Assessment

D-41

reduced to 25 km. The significance of this interference would depend on the period of time the

secondary link is transmitting, and the airborne operations that are occurring during this time.

Analysis of System EMI at Band Edges with IMT-2000 Equipment. If the JTCTS signal is

11.25 MHz from the edge of the band, 42.4 km separation is needed from the IMT-2000 base station

receivers at the band edge frequencies, to avoid interference. If no distance separation is observed, a

frequency separation of 18.8 MHz is necessary. The interference threshold used assumed the desired

signal was 10 dB above the sensitivity level. These distances may be significant, with training ranges

near populated areas.

Analysis of EMC with Other Systems in the 1755-1850 MHz or 1790-1850 MHz Band. The

1755-1850 MHz band is currently shared by JTCTS with tactical radio relay links and missile video and

control links. Reduction of the available spectrum from 95 MHz to 50 (or 60) MHz means, for the

JTCTS systems, that the G/G, or tertiary, link would migrate to another band. The A/A and G/A links,

because one or both ends are on an aircraft at an altitude that may reach 30,000 feet or more, may cause

or suffer interference out to distances approaching radio line of sight (approximately 390 km at

30,000 ft.). EMC of the JTCTS with itself is difficult to attain in this band, especially when adjacent

ranges are considered. For the JTCTS self-compatibility, when adjacent ranges are considered, has not

been predicted to be attainable through frequency separation alone. If the interference margin is

completely taken up by self-interference, addition of interference from other systems would lead to an

incompatible situation..

D.6.1.2.2 Issues of Moving Ground-to-Ground Links to Other Bands

Feasibility Assessment—Fade Margin and Link Length. For the JTCTS, since position

determination is done by the Global Positioning System (GPS) and not through multilateration, only one

microwave link is needed for the tertiary link, to transmit data for monitoring purposes. The amount of

equipment to be changed in frequency is therefore much less than for TACTS/ACMI. The power,

antenna gain, and fade margin effects are expected to be the same. Modifications to TACTS/ACMI to

use GPS for position determination have been suggested also. If such a modification were implemented,

the number of microwave links needed for that system would also be decreased.

Feasibility Assessment—Power, Noise Figure, and Antenna Gain Considerations. The

JTCTS receiver noise figure is 4.5 dB. Receivers with noise figures in this range in the 4 GHz band

appear to be readily available.
DoD IMT-2000 Assessment

D-42

Self-Interference Potential. With the JTCTS, if only one link is used, the potential for selfinterference between ground-to-ground links should not exist.

EMC With Incumbent Equipment-4400-4940 MHz. For the JTCTS G/G link, the EMC situation

with incumbent equipment in the 4400-4940 MHz band is similar to that with TACTS/ACMI, only with

a single link instead of multiple links.

EMC With Incumbent Equipment-7250-8400 MHz. As was the case for the 4400-4940 MHz

band, for the JTCTS G/G link, the EMC situation with incumbent equipment in the 7250-8400 MHz

band is similar to that with TACTS/ACMI, only with a single link instead of multiple links.

D.6.1.3 Results – Option 3

1. It appears to be possible for the A/G and G/A links of TACTS/ACMI to operate in the 1755-1805

MHz (or 1790-1850 MHz) band compatibly, both within the same range and between adjacent

ranges.

2. Operation of the A/A and G/A links of JTCTS within these restricted frequency bands may be

feasible within the same training range, although some distance separation is necessary to avoid

interference to IMT-2000 receivers at the band edges. Compatibility between adjacent ranges has

not been demonstrated, and may not be attainable through frequency separation alone.

3. Because of the reduced spectrum available for all systems, and because the links remaining in the

band have airborne transmitters and receivers, compatibility with equipment remaining in the band is

expected to be made much more difficult to attain.

4. It appears to be feasible to move the G/G links of TACTS/ACMI and JTCTS to either the 4400-4940

MHz or 7250-8400 MHz band. Some equipment at training ranges is assigned frequencies in these

ranges, including threat simulators and point-to-point microwave links. EMC problems with this

equipment are expected to be tractable.

5. Redesigning the TACTS/ACMI to use GPS instead of multilateration for position determination

would reduce the A/G and G/A signal bandwidths from 3 MHz to a value nearer the data rate (198

kHz) and make compatibility with itself and other systems easier to attain. It would also greatly

reduce the number of G/G links to be redesigned to operate in another band.
DoD IMT-2000 Assessment

D-43

D.6.2 Operational Impact

Interference with the ACTS data link will occur dependent on frequency, location, and transmitter power

of future IMT-2000 equipment. The RF interference will adversely affect system operation.

Interference with uplink and downlink frequencies will render ACTS airborne instrumentation

inoperative while interference with ACTS ground-to-ground RF links could vary with portions of the

range becoming inoperative. Additionally, there is no current way to limit system operation to a portion

of the band, therefore it must be assumed ACTS operation will adversely affect IMT-2000 systems.

This would likely cause severe restrictions to TACTS/ACMI emissions thus significantly reducing

system utility.

If the ACTS loses access to parts of the 1755-1850 MHz band in 2006, the impacts would be similar to

those described for 2003 unless modification to the existing frequency plan is pursued. A remanufacture

of existing TACTS/ACMI hardware (updating for obsolescence and technology advances) could make

operation of the legacy systems within a reduced bandwidth feasible. It is estimated the fielding of the

proposed ACTS modifications could be accomplished for all ranges by 2006. However, operational

training will be impacted because of range downtime during installation and checkout of the

modifications. Each range will be completely down for at least 1-3 months with limited capability up to

6 months due to modification of range equipment. A moderate schedule risk is assessed in modifying all

the ACTS ranges by 2006. For 2010, the assessment is the same as the assessment for provided 2006

except that risk is reduced based on additional time to deploy.

The operational impact can be minimized if no spectrum conflicts arise with other Government systems

and all the mitigation efforts are completely implemented by 2006 (schedule risk) or if turnover of

1805-1850 MHz band can be delayed at sites where mitigation measures have not been completed by

2006. The operational impact may be further minimized if ground-to-ground links can be successfully

relocated to other frequency bands. Compatibility with incumbent systems in the bands supporting

relocation may be a major issue.

The replacement of the legacy ACTS by JTCTS is scheduled to begin after 2006. The 2010 time frame

may allow for an accelerated JTCTS program to provide replacement ACTS, provided actions are taken

sufficiently early. A modification program for the legacy ACTS could also be completed by that time

frame—but that would be moot if all systems have been replaced by JTCTS. Any loss of current system

use or functionality would impact the training and readiness of the aircrews, with the impact directly

related to the historical tactical training role/function of the system at a given site.
DoD IMT-2000 Assessment

D-44

D.7 OPTION 4 – VACATING THE 1755-1850 MHZ BAND

In Option 4, the 1755-1850 MHz band is unavailable, and all equipment must be redesigned to operate

in other frequency bands that are allocated to their functions. For this option, both 2200-2290 MHz and

4400-4940 MHz were considered for moving the A/G, A/A, and G/A links. The two bands considered

in Option 3, 4400-4940 MHz and 7250-8400 MHz, were again considered for the G/G links. Again,

feasibility, self-interference, and interference to and from incumbent systems in the band were

considered.

D.7.1 TACTS/ACMI Assessment

D.7.1.1 OPTION 4A – Move A/G and G/A Links to 2200-2290 MHz Band, and Move G/G

Links to 4400-4940 or 7250-8400 MHz Band

With Option 4A, the entire 1755-1850 MHz band is no longer available for ACTS use. Instead of

remaining in a reduced (50 MHz) portion of the present band, the A/G and G/A links of the

TACTS/ACMI will be moved to a higher band. Two candidate bands were considered for this study.

They are the 2200-2290 MHz and 4400-4940 MHz bands. For relocation of a system, especially one

with airborne components, a number of issues must be addressed. The two primary categories of issues

include the feasibility of redesigning equipment to perform its function in the new band, and potential

EMC problems with equipment already using the band. The 2200-2290 MHz band was considered as a

prime candidate for relocation. Because it is closest in frequency to the present band, it is expected to

present a minimum number of redesign problems. However, it is already occupied by a number of

systems considered to be of prime importance to the DoD and others. In addition, compatibility with

other systems operating on board the platforms (aircraft or ship) where the system is installed, need to be

investigated.

Systems presently residing in the 2200-2290 MHz band include Space-Ground Link Subsystem (SGLS)

downlink receivers, missile telemetry links, threat simulators, and the NASA Goldstone Deep Space

Network (DSN) and Space Tracking and Data Network (STDN) receivers located near one of the

training ranges, at Fort Irwin, CA. At the Beaufort MCAS, eight microwave links are assigned

frequencies from 2208 to 2285 MHz. On aircraft and ships, interference from the harmonics of

collocated Joint Tactical Information Distribution System (JTIDS) and Tactical Air Navigation

(TACAN) transmitters need to be considered. In addition, the effect of harmonics of the redesigned

ACTS transmitter on collocated receivers needs to be assessed.
DoD IMT-2000 Assessment

D-45

The effects of moving the G/G links to the 4400-4940 MHz or 7250-8400 MHz band has been treated in

the previous section. For the 4400-4940 MHz band, an additional EMC issue has been created, because

harmonics of transmitters in the 2200-2290 MHz band lie within this frequency range.

Feasibility Assessment. In the 2200-2290 MHz band, the free-space propagation loss is 1.9 dB

higher than in the 1755-1850 MHz band. For G/A and A/G links, omnidirectional antennas are

desirable, and no additional antenna gain can be achieved at the higher frequency, as may be the case

with a dish antenna. Therefore, to maintain the same maximum communications range, the transmitter

power needs to be raised by 1.9 dB. The TACTS/ACMI airborne transmitter power needs to be

increased from 20 to about 30 watts. This power level is lower than the present JTCTS transmitter

power of 67.6 watts, and therefore is considered to be feasible.

Self-Compatibility. In the analysis for the 1755-1850 MHz band, self-compatibility within this band

segment was predicted for the TACTS/ACMI A/G and G/A links. Self-compatibility should still be

attainable in a similar (50-MHz) portion of the 2200-2290 MHz band. For the case of interference to

adjacent ranges, the additional transmitter power should be cancelled by the revised path loss.

EMC with Incumbent Equipment—SGLS Downlink Receivers. The Air Force Satellite

Control Network (AFSCN) provides telemetry, tracking, commanding, control, and communications

functions for manned and unmanned DoD and non-DoD satellite operations and other space vehicle

missions. The terrestrial components of the AFSCN include operations control nodes, common-user

control nodes, remote ground facilities, remote tracking stations, and automated remote tracking

stations. One element of the AFSCN is the SGLS, which provides telemetry, tracking, and commanding

(TT&C), as well as data and voice communications. The SGLS uplink operates between 1760-1845

MHz and the downlink operates between 2200-2290 MHz.

The SGLS downlink signal format can include any combination of ranging code and three subcarriers

(carrier 1), telemetry (carrier 2), and wideband data (carrier 3). Selected downlink signal parameters

relevant to this assessment are provided in Table D-23 below. Certain space vehicles may include a

special S-band communications package that accommodates three carriers on a standard SGLS link.

This is referred to as the M2P1 configuration and provides additional voice and data communications.

For the terminals examined in this analysis, a review of the M2P1 characteristics shows the standard

SGLS downlink to be more susceptible to interference than the M2P1 downlink. Consequently, the

M2P1 receiver analysis is not presented here.
DoD IMT-2000 Assessment

D-46

Table D-23. Nominal SGLS Downlink Signal Characteristics

Nominal SGLS Earth Station

Parameter Value

3 dB Bandwidth/Bit Rate Carrier 1 1.024 MHz subcarrier

PCM telemetry 7.8 bps -128 kbps

1.25 MHz subcarrier

Voice 100 Hz - 3.5 kHz

Analog data 100 Hz - 20 kHz

1.7 MHz subcarrier

PCM/PAM telemetry 125 bps - 256 kbps

PAM telemetry to 20 kHz

2.05 kHz

Carrier 2 128 - 1024 kbps

Carrier 3 0.2 - 10 MHz

AFSCN earth stations that receive the SGLS downlink signals are limited in number and are normally

fixed facilities located at government controlled sites. A list of the fixed terminals is given in

Appendix B. The fixed terminals generally include large, high gain, directional antennas. Within the

control network there are smaller, transportable terminals that function as remote tracking stations and

may be used for range operations and special events. These transportable terminals were the initial

focus of this assessment as these terminals are the most likely to be near an uncontrolled environment,

have lower link margins due to smaller antennas, and consequently may be more subject to interference.

The transportable terminals include the S-band transportable ground station (STGS), the transportable

S-band terminal (TST), and the transportable space test and evaluation resource (TSTR). Of these

terminals, the TST has the smallest antenna, the lower figure of merit, lowest link margin, and has the

lowest interference thresholds. This analysis was performed on carrier 1 (Telemetry) and carrier 2 (1024

kbps) of the TST, using information on link margin and the resulting interference threshold taken from

an earlier JSC analysis.26 Other information was taken from the system frequency allocation

application.27 Separation distances for these terminals were expected to be representative. Relevant

SGLS parameters for a number of TST functions are included in Table D-24 below.

 26 Lloyd Apirian, Ben Benedick, and Ray Dizon, Siting Analysis Supporting Proposed AFSCN MCC Relocation to Kirtland AFB,

JSC-CR-95-015, Annapolis, MD: DoD JSC, May 1995.

27 Application for Equipment Frequency Allocation (DD Form 1494) for Space Ground Link Subsystem (SGLS), J/F 12/1520/4,

Washington, DC, 11 December 1967.
DoD IMT-2000 Assessment

D-47

Table D-24. SGLS Link Budget Values

Item TST Carrier 1 TST Carrier 2

Telemetry Comm Ranging 512 kb/s 1024 kb/s

Effective Received Power (dBm) -110.6 -113.2 -108.1 -101.1 -101.1

Effective Noise Temperature (dBk) 22.9 22.9 22.9 22.9 22.9

N0 (dBm/Hz) -175.7 -175.7 -175.7 -175.7 -175.7

Bandwidth (dBHz) 45.0 43.0 60.0 57.1 60.1

Eb/ N0 (dB)

C/ N0 (dB)

20.1

22.1 67.6

17.5 14.5

Eb/ N0 Required (dB)

C/ N0 Required (dB)

9.6

-23.0 47

9.6 9.6

Link Margin (dB) 10.5 25.1 20.6 7.9 4.9

Required Margin (dB) 3.0 3.0 3.0 3.0 3.0

Excess Margin (dB) 7.5 22.0 17.6 4.9 1.9

N (dBm) -130.7 -132.7 -115.7 -118.6 -115.6

I/Nth (dB) 6.7 8.5 17.5 3.2 -2.6

Interference threshold, Ith, dBm -124.0 -110.7 -98.2 -115.4 -118.2

For the TACTS/ACMI A/G links, if no frequency coordination is assumed, a separation distance of 383

km is necessary to avoid interference to the TST downlink receiver using Carrier 1, and 392 km to avoid

interference to the TST downlink receiver using Carrier 2. To avoid distance separation constraints,

5 MHz and 12 MHz separations are necessary from Carriers 1 and 2, respectively, for the situations

analyzed. The SGLS downlink uses frequencies at 5 MHz intervals throughout the 2200-2290 MHz

band (Reference 26).

EMC with Incumbent Equipment—Missile Telemetry Links. Various systems, such as the

AN/DKT-XX series, the Aydin Vector T-series, etc. are used to telemeter the performance data of a

missile weapon back to a monitoring station. A typical example is the T-802, used in the Advanced

Medium Range Air-to-Air Missile (AMRAAM). This system has a transmitter with a nominal

bandwidth of 2.4 MHz and an output power of about 4 watts. An omnidirectional antenna is normally

used. The telemetry signals are received by range ground terminals, using receivers typified by the

Defense Electronics TR-109. As these systems are generally one-way data links, there is no associated

receiver on board the missile.

For telemetry use at missile test ranges, the band is divided into 89 one-MHz channels, from

2200.5 MHz to 2289.5 MHz. The missile telemetry systems are used principally on or near DoD
DoD IMT-2000 Assessment

D-48

training and weapons ranges. In some circumstances the missiles will be launched from one range and

fly into an impact on another range.

At one of the major ACTS training ranges, Nellis AFB, NV, a number of frequencies throughout the

2200-2290 MHz range are assigned to specific telemetry transmitters. A large number of frequencies

are assigned to the AN/DKT-37D. Information on this transmitter was obtained from the frequency

allocation application28 and frequency-distance separation criteria for avoidance of its interference to the

TACTS/ACMI and JTCTS receivers were calculated. An similar analysis was performed of the effects

of the TACTS/ACMI and JTCTS airborne transmitters on a typical ground-based telemetry receiver, the

Microdyne Model 1100R. Information on this receiver was also taken from its frequency allocation

application.29 For each receiver, an interference threshold of 6 dB below the noise level was used.

For the TACTS/ACMI AIS transmitter interfering with the ground-based telemetry receiver, a 5 MHz

frequency separation or a 392 km distance separation is needed to avoid exceeding the interference

threshold. The AN/DKT-37D missile transmitter is relatively low power (2 W) and narrowband

(0.5 MHz). Therefore the required separation distances and frequencies to avoid interference to the

ACTS receivers are somewhat smaller compared to the ACTS-to-telemetry receiver distance. For the

TACTS/ACMI AIS receiver, the minimum separation distance is 308 km, and the minimum frequency

separation is 3 MHz.

Cosite Equipment at Subharmonics and Harmonics for the F/A-18 Aircraft. An assessment

of the potential interference from equipment collocated with the ACTS on a typical aircraft, the F/A-18,

was performed. The 2200-2290 MHz band contains second harmonics of Tactical Air

Navigation/Distance Measuring Equipment (TACAN/DME) and Joint Tactical Information Distribution

System (JTIDS) frequencies. Both of these equipments are located on the F/A-18 aircraft. The 2200-

2290 MHz band is also a fourth subharmonic of the band occupied by the collocated AN/APN-202

beacon.

The JSC Aircraft inter-Antenna Propagation with Graphics (AAPG) computer program30 was used to

model the F/A-18 aircraft to determine the path loss between antennas on the aircraft structure. The

 28 Application for Equipment Frequency Allocation (DD Form 1494) for AN/DKT-37 Telemetry, J/F 12/5971, Washington, DC,

MCEB, 23 April 1985.

29 Application for Equipment Frequency Allocation (DD Form 1494) for Microdyne Corporation Model 1100R Receiver, J/F 12/2702,

Washington, DC, MCEB, 3 January 1969.

30 W. Klocko, D. Katz, P. Hussar, and E. Smith-Rowland, User Guide for AAPG 2000, JSC-UM-98-094, Annapolis, MD: DoD JSC,

March 1999.
DoD IMT-2000 Assessment

D-49

amount of frequency-dependent rejection (FDR) was then calculated using Equation D-7, derived from

Equation E-3 with Ls and LSP = 0.

FDR = Pt + Gt + Gr - Lp - It (D-7)

where Lp is the path loss from AAPG 2000 and other quantities are as previously defined. An

interference threshold 6 dB below receiver noise, which results in a loss of ten percent of

communications range, was used for the ACTS systems. The value of FDR from Equation D-7, the

transmitter emission spectrum, and the receiver selectivity characteristics were then input to the JSC

Frequency-Dependent Rejection Calculation (FDRCAL) model to determine the amount of frequency

separation necessary for the interference threshold It not to be exceeded.

Cosite Equipment—TACAN/DME. Use of the AAPG model resulted in a path loss of 39 dB

between the TACTS fuselage-mounted antenna (on the nose wheel door) used for the internal TACTS

and the lower TACAN/DME antenna, which is also used for JTIDS. Characteristics of the TACAN

component of the AN/USQ-140 were used in the analysis.31 For TACAN/DME interference to the

TACTS, 63 MHz separation between the TACAN/DME harmonic and the TACTS frequency is needed

for It not to be exceeded. For example, if the TACTS receiver operates on 2250 MHz, TACAN/DME

interrogator frequencies between 1093 and 1156 MHz must be avoided. Any interrogation channels

above 69 would cause the threshold to be exceeded. Channels 1-16 and 60-69, which are designated for

use by the military services for tactical purposes, lie outside this range. Blanking of the TACTS receiver

by the TACAN transmitter could also be investigated.

Cosite Equipment—JTIDS. To avoid JTIDS harmonic interference to TACTS, JTIDS harmonics

must be separated by 31.6 MHz from the TACTS frequency. JTIDS transmitter characteristics were

those of the AN/USQ-140(V) taken from the frequency allocation application (Reference 31). For

example, for TACTS operation at 2250 MHz, JTIDS frequencies between 1109 and 1141 MHz need to

be avoided. A loss of 10 of the 51 available JTIDS frequencies would occur. As with TACAN,

blanking of the TACTS receiver when JTIDS transmits could be investigated.

Cosite Equipment—AN/APN-202. The AN/APN-202 may operate in the 8800-9500 MHz

frequency range, although it often receives on 9310 MHz. A path loss of 48.5 dB was calculated using

 31 Application for Frequency Allocation (DD Form 1494) for Joint Tactical Information Distribution System, Multi Functional

Information Distribution System (JTIDS/MIDS), J/F 12/4413/4 (Draft).
DoD IMT-2000 Assessment

D-50

AAPG-2000. The resulting TACTS harmonic is calculated to be -87.5 dBm. This value is 22.5 dB

below the AN/APN-202 sensitivity of -65 dBm, which was used as the interference threshold.

Therefore, no interference problem is expected.

Other Collocated Systems. Other collocated systems that may be affected by the reassigned

TACTS AIS transmitter include the AN/ALQ-165 jammer and the AN/ALR-067 countermeasures

warning and control system (CWCS). Compatibility with these systems will be assessed in the

classified supplement.

Goldstone Deep Space Network and GSTDN Receivers (Ft. Irwin only). The NASA Deep

Space Network (DSN) receiver at Goldstone, CA is located within the boundaries of Fort Irwin. The

Air Warrior/National Training Center Integration System (AW/NTC-IS) is also located there. One of

the components of the AW/NTC-IS is an ACMI. If this ACMI is moved in frequency to the 2200-2290

MHz band, the DSN receivers will have to be protected.

The primary S-band frequency range used for Deep Space spacecraft communication at Goldstone is

2290-2300 MHz, adjacent to the proposed 2200-2290 MHz band. These frequencies must be protected

during sensitive events. However, the receivers are capable of operating from 2200-2300 MHz,32 and a

number of authorized frequencies of low-earth-orbit (LEO) satellites are listed in the Goldstone

Authorized Frequency Database.33 These frequencies must also be protected.

An assessment of the effects of the ACMI remote and airborne systems on the Goldstone receiver was

done in a manner similar to that done in an earlier analysis.34 For the Goldstone receivers, an

interference threshold of -192 dBm/Hz and an antenna gain of 32 dBi were used. For the ACMI AIS

transmitter at a 9000 km altitude, 432 km of distance separation would be needed to avoid exceeding the

interference threshold. At a point 60 dB down from the maximum peak of the emission spectrum, at ±6

MHz from the carrier frequency, the minimum separation distance would be 106 km. For the ACMI

TIS remote G/A link transmitter, the corresponding separation distances are 93 km and 22 km for the

on-tune and -60 dB points, respectively.

 32 Goddard Space Flight Center, Mission Requirements and Data Systems Support Forecast, Document 501-803, Greenbelt Maryland,

August 1996, p. 7-14.

33 “NTIA S-Band Authorized Frequencies at Goldstone,” [NTIA Web page], 19 May 1999 [cited 29 November 2000]. Available from

http://gts.gdscc.nasa.gov/GFACSEC/GFACFreqs.htm; INTERNET.

34 J. Colaw, V. Casto, and G. Goodwyn, EMC Analysis of the ASET-IV Equipment at Ft. Irwin, Hohenfels, and Ft. Chaffee (U),

ECAC-CR-91-037, Annapolis, MD: DoD ECAC, August 1991, (SECRET) (Declassify on: OADR).
DoD IMT-2000 Assessment

D-51

Threat Simulators. A description of threat simulators operating in this band and EMC issues with a

relocated TACTS/ACMI are included in the classified supplement to this report.

Other Incumbent Equipment. Other equipment operating in the 2200-2290 MHz band includes

point-to-point microwave links at one of the training ranges, Beaufort MCAS. Of the six training ranges

described in Reference 22, only one has microwave links in this band. If the TACTS/ACMI A/G and

G/A links were to move to this band, compatibility with these links is expected to be an issue. It may be

desirable to reassign the microwave link frequencies to a higher band.

EMC with Other Systems That May Migrate to This Band. Other systems considering

migration to this band include weapons control data links. The ACTS coexisted with these systems in a

similar sized piece of spectrum in the 1755-1800 MHz band. Only the A/A, A/G, and G/A links would

move to the 2200-2290 MHz band, so the compatibility situation would be somewhat simpler than in the

present band, if other equipment were not already in the band. However, the existence of other systems,

such as the SGLS downlink receiver, missile telemetry links, and threat radar simulators, already

severely limits the amount of interference-free spectrum available. The addition of weapons control

data links, along with ACTS, would only add more interference possibilities to an extremely crowded

band.

D.7.1.2 OPTION 4B – Move A/G and G/A Links to 4400-4940 MHz Band, and Move G/G

Links to 4400-4940 or 7250-8400 MHz Band

With Option 4B, as with Option 4A, the entire 1755-1850 MHz band is no longer available for ACTS

use. Instead of remaining in a reduced (50 MHz) portion of the present band, the A/G and G/A links of

the TACTS/ACMI will be moved to a higher band. For relocation of a system, especially one with

airborne components, a number of issues must be addressed. The two primary categories of issues

include the feasibility of redesigning equipment to perform its function in the new band, and potential

EMC problems with equipment already using the band. Along with the 2200-2290 MHz band, the

4400-4940 MHz band was considered as a candidate for relocation. Because it is farther in frequency

from the present band, it is expected to present more redesign problems than the 2200-2290 MHz band.

Although the 4400-4990 MHz band offers more spectrum than the 2200-2290 MHz band, it is also

already occupied by a number of systems considered to be of prime importance to the DoD and others.

As with the lower band, compatibility with other systems operating on board the platforms (aircraft or

ship) where the system is installed, need to be investigated.
DoD IMT-2000 Assessment

D-52

Major systems presently residing in the 4400-4940 MHz band include the AN/TRC-170 and AN/GRC222 tactical line-of-sight and troposcatter radios, the US Navy Light Airborne Multipurpose System

(LAMPS) and Cooperative Engagement Capability (CEC). Other systems in the band include HAVE

NAP, which is used on the B-52 aircraft, the Integrated Target Control System (ITCS), which is used at

the Atlantic Fleet Warfare Training Facility (AFWTF), and UAV links, such as the Pioneer UAV. As

with the 2200-2290 MHz band, on aircraft and ships, interference from the harmonics of collocated Joint

Tactical Information Distribution System (JTIDS) and Tactical Air Navigation (TACAN) transmitters

need to be considered. In addition, the effect of harmonics of the redesigned ACTS transmitter on

collocated receivers needs to be assessed. Threat simulators have also been assigned frequencies in the

4900-4990 MHz range at the NAS Oceana training range.

The effects of moving the G/G links to the 4400-4940 MHz or 7250-8400 MHz band has been treated in

the previous section. For G/G links in the 4400-4940 MHz band, an additional EMC issue has been

created, because all links of the ACTS systems, A/G, G/A, and A/A would have to coexist in this band.

Feasibility Assessment. To maintain the same communications range at 4.4 GHz with

omnidirectional antennas, the transmitter powers would have to be increased by 7.8 dB. The

TACTS/ACMI AIS transmitter would have to be increased in power from 20 to 121 watts. Devices in

this power range for 2200-2290 MHz are apparently available, although not built to military

specifications. Going to the higher frequency band adds an extra level of difficulty, and it is not known

if transmitters at this power level can meet the power and weight constraints of fighter aircraft. It may

be possible to use lower power, with the addition of a high-gain antenna with tracking capabilities at the

ground station. The feasibility of this arrangement and the ability to track maneuvering aircraft would

need to be determined.

Self-Compatibility. In the analysis for the 1755-1850 MHz band, self-compatibility within this band

segment was predicted for the TACTS/ACMI A/G and G/A links. Self-compatibility for these links

should still be attainable in a similar (50-MHz) portion of the 4400-4940 MHz band. For the case of

interference to adjacent ranges, the additional transmitter power needed should be cancelled by the

revised path loss. If the G/G links were also to be in this band, more than 72 MHz would be needed, as

was the case for 1755-1850 MHz band.

EMC with Incumbent Equipment—AN/TRC-170/AN/GRC-222. Frequency and distance

separations necessary to avoid interference from the TACTS/ACMI AIS transmitter to the AN/TRC-170

receiver in the line-of-sight (LOS) and troposcatter configurations were calculated using characteristics
DoD IMT-2000 Assessment

D-53

and thresholds from an earlier analysis.35 For the LOS mode, an interference threshold of -76 dBm,

corresponding to a reliability of 99.99% for a link length of 20 km, was used. For the troposcatter mode,

a threshold of -100 dBm, corresponding to 99.99% reliabiliity for a link length of 100 km, was used.

Thresholds were determined from Figures 1 and 2 of Reference 35. Calculations for the AN/TRC-170

mainbeam (44 dBi), near-sidelobe (10 dBi) and backlobe (0 dBi) gains were made. Results are given in

Table D-25. Distance separations in Table D-25 assume no off-tuning, and frequency separations

assume a 1 km separation distance. Values in parentheses are for the power raised by the amount to

achieve the same communications range at 4600 MHz as at 1800 MHz.

Table D-25. Distance and Frequency Separations Necessary to Avoid Interference From

TACTS/ACMI AIS Transmitter to AN/TRC-170 Receivers

Mode AN/TRC-170 Gain, dBi Distance, Km Frequency, MHz

0 00

10 8 2

LOS

44 386 6

0 60 (155) 4 (4.7)

10 192 (384) 5 (5.9)

Troposcatter

44 404 (410) 12.7 (19.1)

From Table D-25 it can be seen that a reasonable amount of frequency separation between

TACTS/ACMI and AN/TRC-170 equipment should be observed, especially when the TACTS/ACMI

aircraft may fly through the mainbeam of the AN/TRC-170 transmitter antenna.

EMC with Incumbent Equipment—Pioneer UAV. The Pioneer unmanned aerial vehicle (UAV)

has RF links at UHF and C band. There is a primary C band link at 4 GHz and an alternate link at

5 GHz. The 4430-4590 MHz frequency range supports the primary uplink and 4750-4950 MHz

supports the downlink. The downlink data may be video, infrared sensor information, or telemetry data,

and the uplink is command data. In CONUS, use of the Pioneer UAV generally occurs at the test ranges

of the Southwest or at sea. Pioneer flights take place on an intermittent basis. Two methods of

addressing compatibility issues with Pioneer are coordinating times of Pioneer flights with ACTS

training missions, and using the alternate (5 GHz) link.

EMC with Incumbent Equipment—AGM-142 (HAVE NAP). The AGM-142 missile is operational

on B-52 aircraft. Training missions for this missile can occur anywhere over the US, but generally in

 35 Suresh Agarwal, Analysis of the AN/TRC-170 When Deployed As Part of the Tactical Air Control System, ECAC-PR-78-071,

Annapolis, MD, DoD ECAC, December 1978.
DoD IMT-2000 Assessment

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Western regions. Live launches usually occur at White Sands Missile Range and at the Utah Test and

Training Range. Maintenance and checkout is usually performed at Barksdale AFB, LA. Specific

frequency ranges and other characteristics of this system are classified. The AGM-142 will not be

addressed further in this study.

EMC with Incumbent Equipment—LAMPS. Compatibility issues with LAMPS are described in

the classified supplement.

EMC with Incumbent Equipment—CEC. CEC is a system that provides the means to conduct

coordinated Anti-Air Warfare (AAW) area defense. All Cooperating Units (CU) that participate in a

CEC network exchange sensor data in near real time to form an identical composite track and

identification air surveillance picture on each CU. This sensor cooperation function allows targets to be

detected and compositely tracked that a single individual sensor could not track. The composite air

picture provides the means for a battle force to accomplish optimized weapon system assignments and

the coordinated engagements of threats. CEC is implemented via a Cooperative Engagement Processor

(CEP) and a Data Distribution System (DDS). The CEP is a computer system responsible for forming

the composite track and identification data base, and for coordinating engagements. The DDS is an RF

network responsible for the secure, environmentally resistant transfer of sensor and weapon data among

the CUs. CEC is currently being deployed aboard Navy E-2C aircraft and the major Navy surface

combatants, carriers, and amphibious class ships. CEC is also now in development for deployment with

the USA PATRIOT, USAF Airborne Warning and Control System (AWACS), and USMC AN/SPS-59

radar systems. The parameters for CEC are provided in Table C-30.

EMC with Incumbent Equipment—Threat Simulators. Threat simulators in the 4900-4990 MHz

frequency range have been assigned frequencies at the NAS Oceana training range (Reference 22). This

band overlaps part of the 4400-4940 MHz band. At Oceana, and at other ranges that may use threat

simulators in this band, assignment of ACTS frequencies in the 4900-4940 MHz range should be

avoided. A list of threat radars in the 4400-4940 MHz band is given in the classified supplement.

Cosite Equipment at Subharmonics and Harmonics for the F/A-18 Aircraft. An assessment

of the potential interference from equipment collocated with the ACTS on a typical aircraft, the F/A-18,

was performed. The 4400-4940 MHz band contains fourth harmonics of Tactical Air

Navigation/Distance Measuring Equipment (TACAN/DME) and Joint Tactical Information Distribution

System (JTIDS) frequencies. Both of these equipments are located on the F/A-18 aircraft. The 4400-

4940 MHz band is also a second subharmonic of the band occupied by the collocated AN/APN-202

beacon and AN/APG-65/73 fire control radar.
DoD IMT-2000 Assessment

D-55

As was done for the 2200-2290 MHz band, the JSC Aircraft inter-Antenna Propagation with Graphics

(AAPG) computer program was used to model the F/A-18 aircraft to determine the path loss between

antennas on the aircraft structure. An analysis to determine the frequency constraints on the

fundamental emitter to avoid potential interference from its harmonic was then performed.

Cosite Equipment—TACAN/DME. Use of the AAPG model resulted in a path loss of 45 dB

between the TACTS fuselage-mounted antenna (on the nose wheel door) used for the internal TACTS

and the lower TACAN/DME antenna, which is also used for JTIDS. For TACAN/DME interference to

the TACTS, 31.6 MHz separation between the TACAN/DME harmonic and the TACTS frequency is

needed for It not to be exceeded. For example, if the TACTS receiver operates on 4600 MHz,

TACAN/DME interrogator frequencies above 1142 MHz must be avoided. Any interrogation channels

above 118 would cause the threshold to be exceeded.

Cosite Equipment—JTIDS. To avoid JTIDS harmonic interference to TACTS, JTIDS harmonics

must be separated by 8.8 MHz from the TACTS frequency. A rejection value of 80 dB was assumed for

the fourth harmonic (Reference 31). For example, for TACTS operation at 4600 MHz, JTIDS

frequencies between 1148 and 1152 MHz need to be avoided. A loss of two of the 51 available JTIDS

frequencies would occur.

Cosite Equipment—AN/APN-202. The TACTS, in the 4400-4940 MHz band, lies at the second

subharmonic of the AN/APN-202 beacon frequency range. The TACTS second harmonic is calculated

to be -87.5 dBm, 22.5 dB lower than the AN/APN-202 sensitivity of -65 dBm. Interference to the

AN/APN-202 is not expected.

Cosite Equipment—Fire Control Radar. The TACTS, in the 4400-4940 MHz band, lies at the

second subharmonic of the AN/APG-65/73 radar tuning range. An assessment of interference to the

radar is included in the classified supplement.

Cosite Equipment—AN/APN-194 Radar Altimeter. The AN/APN-194 Doppler radar altimeter

operates at a center frequency of 4300 MHz. At least 61 dB rejection of the TACTS AIS signal is

necessary for the signal to be below the -85 dBm sensitivity level of the AN/APN-194. This rejection

should be attainable at a frequency separation of less than 100 MHz. At least 101 dB of rejection is

needed for the AN/APN-194 signal peak power to be below the TACTS AIS interference threshold. If

this amount of FDR is not attainable, because of the low duty cycle of the altimeter, (.00072), blanking

of the TACTS receiver may be a feasible mitigation technique.
DoD IMT-2000 Assessment

D-56

Other Collocated Systems. Other collocated systems that may be affected by the reassigned

TACTS AIS transmitter include the AN/ALQ-165 jammer and the AN/ALR-067 CWCS.

Compatibility with these systems will be assessed in the classified supplement.

Compatibility with Other Systems Migrating to This Band. The 4400-4940 MHz band contains

more spectrum (540 MHz) compared to the lower bands, so compatibility with the additional equipment,

such as weapons control data links, that may migrate to the 4400-4940 MHz band would be more readily

achieved than at the lower bands. This situation would occur even if the G/G links were moved to the

band. However, the presence of the systems already in the band may negate most of the advantage

given by the wider bandwidth.

D.7.2 JTCTS A/A and G/A Links Technical Assessment

D.7.2.1 OPTION 4A – Move G/A and A/A Links to 2200-2290 MHz Band, and Move G/G

Links to 4400-4940 or 7250-8400 MHz Band

With Option 4A, the entire 1755-1850 MHz band is no longer available for ACTS use. Instead of

remaining in a reduced (50 MHz) portion of the present band, the G/A and A/A links of the JTCTS will

be moved to a higher band. Two candidate bands were considered for this study. They are the 2200-

2290 MHz and 4400-4940 MHz bands. For relocation of a system, especially one with airborne

components, a number of issues must be addressed. The two primary categories of issues include the

feasibility of redesigning equipment to perform its function in the new band, and potential EMC

problems with equipment already using the band. The 2200-2290 MHz band was considered as a prime

candidate for relocation. Because it is closest in frequency to the present band, it is expected to present

a minimum number of redesign problems. However, it is already occupied by a number of systems

considered to be of prime importance to the DoD and others. In addition, compatibility with other

systems operating on board the platforms (aircraft or ship) where the system is installed, need to be

investigated.

Systems presently residing in the 2200-2290 MHz band include Space Ground Link Subsystem (SGLS)

downlink receivers, missile telemetry links, threat simulators, and the NASA Goldstone Deep Space

Network (DSN) and Space Tracking and Data Network (STDN) receivers located near one of the

training ranges, at Fort Irwin, CA. At the Beaufort MCAS, eight microwave links are assigned

frequencies from 2208 to 2285 MHz. On aircraft and ships, interference from the harmonics of

collocated Joint Tactical Information Distribution System (JTIDS) and Tactical Air Navigation
DoD IMT-2000 Assessment

D-57

(TACAN) transmitters need to be considered. In addition, the effect of harmonics of the redesigned

ACTS transmitter on collocated receivers needs to be assessed.

The effects of moving the G/G links to the 4400-4940 MHz or 7250-8400 MHz band has been treated in

the previous section. For the 4400-4940 MHz band, an additional EMC issue has been created, because

harmonics of transmitters in the 2200-2290 MHz band lie within this frequency range.

Feasibility Assessment. As was the case for the TACTS/ACMI, the JTCTS transmitter powers

would have to be increased by 1.9 dB, or, in the case of JTCTS, to 105 watts. According to JTCTS

program consultants (Reference 24), high power devices for this band are available, but they do not meet

military specifications for packaging or temperature range. Although individual parts may need to be

screened, implementation is believed to be feasible.

Self-Compatibility. In the analysis for the 1755-1805 MHz band, it was found that compatibility

within the same range could be attained at a 20-km distance between G/A and A/A links, if the

frequency separation between the two links was 35 MHz or more. Compatibility could therefore be

attained in a 58-MHz portion of the 2200-2290 MHz band. Compatibility between links of adjacent

ranges requires an additional 22.8 MHz for each link. Adding the additional 45.6 MHz to the 58 MHz

needed for compatibility within the same range results in 103.6 MHz, greater than 90 MHz. Therefore,

even if compatibility with other systems within the band were of no concern, compatibility between

adjacent ranges cannot be achieved by frequency separation alone in the 2200-2290 MHz band.

EMC with Incumbent Equipment—SGLS Downlink Receivers. An analysis of interference

from the JTCTS air-to-air link to the SGLS downlink receivers was conducted in a manner similar to

that described for the TACTS/ACMI air-to-ground link transmitter. For TST Carrier 1, a 392 km

distance separation is needed for no frequency separation constraints, and for TST Carrier 2, 402 km

separation is needed. The frequency separation constraints are somewhat larger than for the

TACTS/ACMI, because of the wider bandwidth of the JTCTS. For Carrier 1, 27 MHz separation is

needed at minimal distance, and for Carrier 2, 37 MHz separation is needed.

EMC with Incumbent Equipment—Missile Telemetry Links. An analysis for required

frequency and distance separations between the JTCTS airborne transmitter and a ground-based

telemetry receiver, the Microdyne 1100R, and between the AN/DKT-37 missile telemetry transmitter

and the JTCTS airborne receiver was conducted, using methodology similar to that used for the

TACTS/ACMI equipment described above.
DoD IMT-2000 Assessment

D-58

For the JTCTS A/A transmitter interfering with the ground-based telemetry receiver, a 35-MHz

frequency separation or a 401 km distance separation is needed to avoid exceeding the interference

threshold. The larger frequency separation and separation distance for the JTCTS, as compared to the

TACTS/ACMI, are due to its broader bandwidth and higher power level. The JTCTS high power and

wideband modes were assumed for this analysis. To avoid the missile telemetry transmitter signal

exceeding the interference threshold of the JTCTS airborne receiver, a distance separation of 117 km or

a frequency separation of 27 MHz must be maintained.

Cosite Equipment at Subharmonics and Harmonics for the F/A-18 Aircraft. An

investigation of JTCTS transceiver interference effects from and to collocated transmitters and receivers

on the F/A-18 aircraft was performed in the same manner as described for the TACTS/ACMI. The

results are discussed below.

Cosite Equipment—TACAN/DME. To avoid TACAN/DME interference to JTCTS, about 100

MHz of frequency separation would be needed. The increased frequency separation, compared to

TACTS, is largely due to the wider bandwidth of the JTCTS receiver. All TACAN/DME channels

above 50 would cause harmonics above the threshold level. The military-only channels 1-16 would

continue to generate harmonics below the interference threshold.

Cosite Equipment—JTIDS. To avoid JTIDS harmonic interference to JTCTS, about 63 MHz

frequency separation is needed. JTIDS frequencies between 1093 and 1157 MHz would cause the

interference threshold to be exceeded for the hypothetical situation of JTCTS operating at 2250 MHz.

Of the 51 JTIDS frequencies, 21 would exceed the interference threshold.

Cosite Equipment—AN/APN-202. The second harmonic of the JTCTS at the AN/APN-202

receiver input is calculated to be -71.2 dBm, lower than the -65 dBm sensitivity of the AN/APN-202

receiver. Interference to the AN/APN-202 from JTCTS in the 2200-2290 MHz band is not expected to

be a problem.

Other Collocated Systems. Other collocated systems that may be affected by the reassigned

JTCTS airborne transmitter include the AN/ALQ-165 jammer and the AN/ALR-067 CWCS.

Compatibility with these systems will be assessed in the classified supplement.

Collocated Shipboard Systems. The JTCTS, when used for exercises at sea, is expected to have a

transmitter and possibly a receiver on board ship. Compatibility of these systems with other shipboard

equipment would need to be assessed.
DoD IMT-2000 Assessment

D-59

Goldstone Deep Space Network and GSTDN Receivers (Ft. Irwin only). An assessment of

the effects of the JTCTS airborne transmitter on the Goldstone receiver was done in a manner similar to

that described above for the ACMI systems. At a 9000 m altitude, 439 km of separation is needed to

avoid exceeding the interference threshold with no offtuning, and 309 km separation is needed at the -60

dB spectral level, ± 11.25 MHz.

Threat Simulators. A description of threat simulators operating in this band and EMC issues with a

relocated JTCTS are included in the classified supplement to this report.

Other Incumbent Equipment. Other equipment operating in the 2200-2290 MHz band includes

point-to-point microwave links at one of the training ranges, Beaufort MCAS. Of the six training ranges

described in Reference 22, only one has microwave links in this band. If the JTCTS A/A and G/A links

were to move to this band, compatibility with these links is expected to be an issue. It may be desirable

to reassign the microwave link frequencies to a higher band.

EMC with Other Systems That May Migrate to This Band. As with the TACTS/ACMI,

addition of weapons control data links, or other systems, to this band due to overall reduction of

spectrum available to DoD only adds more interference possibilities to an already overcrowded band.

D.7.2.2 OPTION 4B – Move G/A and A/A Links to 4400-4940 MHz Band, and Move G/G

Links to 4400-4940 or 7250-8400 MHz Band

With Option 4B, as with Option 4A, the entire 1755-1850 MHz band is no longer available for ACTS

use. Instead of remaining in a reduced (50 MHz) portion of the present band, G/A and A/A links of the

JTCTS will be moved to a higher band. For relocation of a system, especially one with airborne

components, a number of issues must be addressed. These issues for the JTCTS are much the same as

for the TACTS/ACMI, described earlier. The two primary categories of issues include the feasibility of

redesigning equipment to perform its function in the new band, and potential EMC problems with

equipment already using the band. Because the 4400-4940 MHz band is farther in frequency from the

present band, it is expected to present more redesign problems than the 2200-2290 MHz band. Although

the 4400-4990 MHz band offers more spectrum than the 2200-2290 MHz band, it is also already

occupied by a number of systems considered to be of prime importance to the DoD and others. As with

the lower band, compatibility with other systems operating on board the platforms (aircraft or ship)

where the system is installed, need to be investigated.
DoD IMT-2000 Assessment

D-60

Major systems presently residing in the 4400-4940 MHz band have been listed in the TACTS/ACMI

discussion, and will be repeated here for convenience. They include the AN/TRC-170 and AN/GRC222 tactical line-of-sight and troposcatter radios, the US Navy Light Airborne Multipurpose System

(LAMPS) and Cooperative Engagement Capability (CEC). Other systems in the band include HAVE

NAP, which is used on the B-52 aircraft, the Integrated Target Control System (ITCS), which is used at

the Atlantic Fleet Warfare Training Facility (AFWTF), and UAV links, such as the Pioneer UAV. As

with the 2200-2290 MHz band, on aircraft and ships, interference from the harmonics of collocated Joint

Tactical Information Distribution System (JTIDS) and Tactical Air Navigation (TACAN) transmitters

need to be considered. In addition, the effect of harmonics of the redesigned ACTS transmitter on

collocated receivers needs to be assessed. Threat simulators have also been assigned frequencies in the

4900-4990 MHz range at the NAS Oceana training range.

The effects of moving the G/G links to the 4400-4940 MHz or 7250-8400 MHz band has been treated in

the previous sections. For G/G links in the 4400-4940 MHz band, an additional EMC issue has been

created, because all links of the ACTS systems, A/G, G/A, and A/A would have to coexist in this band.

Feasibility Assessment. To operate without reduced communications range in the 4400-4940 MHz

band, the JTCTS transmitter would have to be increased in power to 400 watts. According to JTCTS

program consultants (Reference 24), for aircraft using the pod version of the JTCTS, the prime power

available at the wing station is not sufficient to provide this amount of transmitter power. Operating the

JTCTS at this frequency band with omnidirectional antennas, as is necessary for the air-to-air link, may

not be feasible.

Self-Compatibility. According to analyses referred to for the 2200-2290 MHz band, 103 MHz was

predicted to be necessary for compatibility of both G/A and A/A links in the same range and adjacent

ranges. Although this amount of spectrum was not available in the lower bands, it should be available,

barring interference problems with incumbent systems, in the 4400-4940 MHz band. If compatibility

with incumbent systems can be managed, the available spectrum should be able to include the tertiary

(G/G) link as well.

EMC with Incumbent Equipment—AN/TRC-170/AN/GRC-222. Frequency and distance

separations necessary to avoid interference from the JTCTS airborne transmitter to the AN/TRC-170

receiver in the line-of-sight (LOS) and troposcatter configurations were calculated using the methods

described for the TACTS/ACMI analysis. The results are given in Table D-26. Frequency separations

to be observed are somewhat larger than for the TACTS/ACMI AIS. Frequency separations of up to 20

MHz should be observed, even if the mainbeam of the AN/TRC-170 is avoided. In Table D-26,
DoD IMT-2000 Assessment

D-61

numbers in parentheses are for the JTCTS transmitter power raised to meet the same communications

range as at 1800 MHz.

Table D-26. Distance and Frequency Separations Necessary to Avoid Interference From JTCTS

Airborne Transmitter to AN/TRC-170 Receivers

Mode AN/TRC-170 Gain, dBi Distance, Km Frequency, MHz

0 5 2.2

10 33 (86) 6 (11.2)

LOS

44 393 29

0 171 (383) 14 (18.9)

10 385 (391) 20 (26.5)

Troposcatter

44 411 (416) 67 (69)

EMC with Incumbent Equipment—LAMPS. Compatibility issues with LAMPS are described in

the classified supplement.

EMC with Incumbent Equipment—CEC. Compatibility issues between the JTCTS and the CEC

are described in the classified supplement.

EMC with Incumbent Equipment—Threat Simulators. As mentioned earlier,threat simulators in

the 4900-4990 MHz frequency range have been assigned frequencies at the NAS Oceana training range

(Reference 22). This band overlaps part of the 4400-4940 MHz band. At Oceana, and at other ranges

that may use threat simulators in this band, assignment of ACTS frequencies in the 4900-4940 MHz

range should be avoided. A list of threat radars in the 4400-4940 MHz band is given in the classified

supplement.

Cosite Equipment at Subharmonics and Harmonics for the F/A-18 Aircraft. An

investigation of JTCTS transceiver interference effects from and to collocated transmitters and receivers

on the F/A-18 aircraft was performed in the same manner as described for the TACTS/ACMI. The

results are discussed below.

Cosite Equipment—TACAN/DME. To avoid TACAN/DME interference to JTCTS, about 54.5

MHz of frequency separation would be needed. The increased frequency separation, compared to

TACTS, is largely due to the wider bandwidth of the JTCTS receiver. For JTCTS operation at mid-band

(4600 MHz), all TACAN/DME channels above 112 would cause harmonics above the threshold level.
DoD IMT-2000 Assessment

D-62

Cosite Equipment—JTIDS. To avoid JTIDS harmonic interference to JTCTS, 27.4 MHz of

frequency separation is needed. JTIDS frequencies between 1143 and 1157 MHz would cause the

interference threshold to be exceeded for the hypothetical situation of JTCTS operating at 4600 MHz.

Of the 51 JTIDS frequencies, five would exceed the interference threshold.

Cosite Equipment—AN/APN-202. The JTCTS, in the 4400-4940 MHz band, lies at the second

subharmonic of the AN/APN-202 beacon frequency range. The JTCTS second harmonic is calculated

to be -71.2 dBm, 6.2 dB lower than the AN/APN-202 sensitivity of -65 dBm. Interference to the

AN/APN-202 is not expected.

Cosite Equipment—Fire Control Radar. The JTCTS, in the 4400-4940 MHz band, lies at the

second subharmonic of the AN/APG-65/73 radar tuning range. An assessment of interference to the

radar is included in the classified supplement.

Cosite Equipment—AN/APN-194 Radar Altimeter. The AN/APN-194 Doppler radar altimeter

operates at a center frequency of 4300 MHz. At least 72 dB rejection of the JTCTS signal is necessary

for the signal to be below the -85 dBm sensitivity level of the AN/APN-194. This rejection should be

attainable at a frequency separation of less than 100 MHz. At least 98 dB of rejection is needed for the

AN/APN-194 signal peak power to be below the JTCTS interference threshold. If this amount of

rejection is not attainable through frequency separation, the low duty cycle of the altimeter, (.00072),

may allow blanking of the JTCTS receiver as a feasible mitigation technique.

Other Collocated Systems. Other collocated systems that may be affected by the reassigned JTCTS

airborne transmitter include the AN/ALQ-165 jammer and the AN/ALR-067 CWCS. Compatibility

with these systems will be assessed in the classified supplement

Compatibility with Other Systems Migrating to This Band. The same situation applies to the

JTCTS as to TACTS/ACMI. As this band contains more spectrum (540 MHz) compared to the lower

bands, compatibility with the additional equipment, such as weapons control data links, in the band

would be more readily achieved than at the lower bands. This situation would occur even if the G/G

links were moved to the band. However, the presence of the systems already in the band may negate

most of the advantage given by the wider bandwidth. Since the JTCTS uses more transmitter power and

receiver bandwidth, compatibility appears to be more difficult to achieve than is the case with

TACTS/ACMI.
DoD IMT-2000 Assessment

D-63

D.7.3 Results – Option 4

1. It is generally feasible to redesign the TACTS/ACMI or JTCTS airborne transmitters to attain the

present system ranges at 2200-2290 MHz.

2. A number of systems operating in the 2200-2290 MHz band would present compatibility problems

and possibly operational constraints. They include:

a. Missile telemetry links, at Nellis AFB and elsewhere

b. SGLS fixed and transportable S-band downlink terminals

c. NASA Goldstone DSN and GSTDN receivers, at Fort Irwin, CA

d. Threat radar simulators (see classified supplement)

e. Point-to-point microwave links (Beaufort MCAS)

3. Use of the redesigned system at 2200-2290 MHz on a typical fighter aircraft presents potential cosite

EMC problems with other systems on that aircraft. These systems include:

a. TACAN/DME interrogators

b. JTIDS

c. Jammers

d. Radar Warning Receivers

4. It is probably not feasible to redesign the JTCTS transmitter to operate in the 4400-4940 MHz band

with a 150-nmi range to be installed on present-day fighter aircraft.

5. The number of systems already operating in the 4400-4940 MHz band is somewhat smaller than at

2200-2290 MHz. These systems include:

a. Tactical point-to-point and troposcatter radios

b. Unmanned aerial vehicles

c. Cooperative Engagement Capability (CEC) (See classified supplement)

d. Threat simulators (See classified supplement)

6. The CEC is expected to be the primary contender for spectrum in this band.

7. As with the 2200-2290 MHz band, use of the redesigned system on a fighter aircraft, if feasible,

presents a number of cosite interference problems, similar to the ones mentioned for 2200-2290

MHz.

8. EMC issues with G/G links, migrating to the 4400-4940 MHz or 7250-8400 MHz band, are expected

to be tractable, as was the case for Option 3.

D.7.4 Operational Impact

One option presented by the Air Force is to upgrade all ACTS ranges and AIS pods with a GPS tracking

capability and replace existing RF hardware with new, state of the art, digital equipment. AIS pod
DoD IMT-2000 Assessment

D-64

uplink and downlink frequencies could also be moved to the 2200-2290 MHz band. Use of GPS for

position determination will reduce the bandwidth of the uplinks and downlinks, from greater than

7 MHz to less than 1.2 MHz and also eliminate the use of multiple frequency assignments for ground-toground communications resulting in reduced total bandwidth required for ACTS ranges. Moving the

TACTS/ACMI to a different band could not be implemented by 2003 or likely by 2006. Therefore,

vacating the current band in those time frames would impose unacceptable impact to combat training.

One of the above options for moving to an alternate frequency band could possibly be implemented by

2010. However, unless continued operation of legacy TACTS/ACMI is assured in the interim,

operational impacts would be severe.

By 2003, JTCTS will not yet be deployed in the US and it would be difficult to make any significant

modifications to the legacy TACTS/ACMI.Operational impact to US forces is the same as in Option 1.

In 2010,the replacement of the legacy TACTS/ACMI by JTCTS will have just begun (2008).The 2010

time frame may allow for an accelerated JTCTS program to provide replacement TACTS/ACMI. A

modification program for the legacy TACTS/ACMI could also be completed by that time frame—but

that would be moot if all systems have been replaced by JTCTS. Operational impact is none if no

spectrum conflicts arises with other systems and all the mitigation efforts are completely implemented

by 2010 or if turnover of 1755-1850 MHz can be delayed at sites where mitigation measures have not

been completed by 2010. Compatibility issues with incumbent systems in the 2200-2290 and 4400-

4940 MHz frequency bands may prevent the implementation of this option.
DoD IMT-2000 Assessment

E-1

APPENDIX E – OTHER SYSTEMS

The operations of a number of additional Department of Defense (DoD) systems rely on spectrum

between 1755 and 1850 MHz in addition to those of the four primary DoD functional capabilities.

Long-range, low-capacity (data rate), point-to-point microwave system operations represent a majority

of the systems. These systems primarily operate at fixed locations and employ directional antennas. A

number of mobile operations are also authorized in this band although few are considered to represent

dominant uses. Two mobile systems, the Combat Identification for the Dismounted Soldier (CIDDS)

and the Land Warrior Wireless Local Area Network (WLAN), are developmental systems whose

operations also are dependent on spectrum in this band segment. CIDDS entered into development in

1997 and the low-rate initial production of fifty units will be tested in FY01. Current program

documentation indicates approximately 100,000 CIDDS units will be procured to outfit dismounted

soldiers of all three military services. Land Warrior is a first-generation integrated fighting system for

dismounted soldiers. Current program documentation indicates a minimum of 41,000 units, with a

potential increase to 71,000 units, are to be produced commencing in calendar 2003. A number of

Unmanned Aerial Vehicles (UAVs), such as the Pointer (FQM-151A) and the Exdrone (BQM-147A),

are also authorized in this band. These systems transmit video and status data from the UAV to the

ground control system (GCS) using analog frequency modulated (FM) video and data on subcarriers.

Fixed point-to-point microwave, CIDDS, the Land Warrior WLAN, and UAVs are believed to represent

significant other uses of the 1755 to 1850 MHz band.

Technical, cost, and operational impact analyses have been provided for each of the aforementioned

systems. Impact assessments associated with the 1755 to 1850 MHz band reallocation have also been

provided for the Aberdeeen Test Center (ATC) telemetry system and the Nellis Air Force Base

TCM-601 television ordnance scoring system (TOSS).

E.1 POTENTIAL FOR INTERFERENCE TO AND FROM FIXED POINT-TOPOINT COMMUNICATIONS

The 1755-1850 MHz band is considered to be the Federal Government’s general purpose, long-range,

low-capacity, point-to-point microwave band. These systems provide a small number of voice, digital

control, or monitoring channels through which information is routed to and from remote locations.

Typical uses for this band include backbone communications at military test and training ranges, and

supervisory control and data acquisition (SCADA) for electrical power generation, locks, and dams.

Most of these microwave systems are capable of operation between 1710 and 1900 MHz. Originally
DoD IMT-2000 Assessment

E-2

allocated to operate between 1710 and 1855 MHz, the lower band segment was to be reallocated in

accordance with the Omnibus Budget Reconciliation Act of 1993 (OBRA-93) between January 1999

and January 2004. Recently, the Federal Communications Commission (FCC) published their intent to

reassign the lower band segment by 30 September 2002, although a small number of special operations

were exempted from reassignment.1

 Exempted operations include those at 333 Federal power agency

(FPA) sites and 111 additional sites located outside 25 densely-populated US cities where emergency,

disaster response, safety-of-life, and other critical operations exist.

E.1.1 Operational Mission Overview

Point-to-point microwave systems whose operations require access to spectrum in the 1755-1850 MHz

band are employed by the DoD for the transmission of voice and data communications to and from

military hydrologic and range facilities. While their data throughput is minimal, compared to the

throughput of other current-day transmission media, their relative importance remains quite high due to

the nature of their mission. Dams are employed to protect lives and property of downstream inhabitants

and, in some instances, are also employed to generate electrical power. River locks are employed to

facilitate shipborne navigation between and along United States (US) waterways. Most of the point-topoint communications that have hydrologic-related functions are operated by the Army Corps of

Engineers (ACE). All three services also rely on point-to-point microwave systems for backbone

communications at military operating areas in the continental US (CONUS). It is through such

communications networks that range telemetry data and voice communications are routed to facilities

where the particular test or exercise is being scored or monitored. Most installations of microwave

systems that employ spectrum in this band are legacy in nature. Typical replacement media include

point-to-point systems that employ higher regions of radio frequency (RF) spectrum and fiber-optic

cable. Figure E-1 depicts the locations of military point-to-point communications systems in CONUS.

E.1.2 System Descriptions

Typical characteristics of DoD point-to-point microwave systems, which require spectrum in the

1755-1850 MHz are contained in Table E-1.

 

1

 Policy Statement, Principles for Reallocation of Spectrum to Encourage the Development of Telecommunications

Technologies for the New Millenium, FCC 99-354, Washington, DC: Federal Communications Commission, 22 November

1999.
DoD IMT-2000 Assessment

E-3

Table E-1. Typical DoD Point-to-Point Microwave System Characteristics2

Frequency Range 1700 to 1900 MHz

Average Power 1 to 10 watts

Bandwidth 0.5 to 10 MHz

Transmission Capacity 24 to 600 channels

Transmit/Receive Spacing (common antenna) 20 to 50 MHz

Antenna Gain 28 to 34 dBi

Antenna Height 10 to 100 m

Excluding systems employed by ACE, which are discussed in further detail hereafter, the majority of

DoD microwave operations are located in the Desert Southwest (e.g., Arizona, California, Nevada, New

Mexico, and Utah) and the Southeast (e.g., Alabama, Florida, Georgia, North Carolina, and South

Carolina). Including ACE operations, locations where all three military services are authorized by

permanent frequency assignment to employ fixed point-to-point microwave systems in CONUS are

depicted in Figure E-1.

Figure E-1. DoD 1755 to 1850 MHz Point-to-Point Communications Locations

 

2

 R. Matheson, Spectrum Usage for the Fixed Services, NTIA Report 00-378, Washington, DC: US Department of

Commerce, March 2000.
DoD IMT-2000 Assessment

E-4

E.1.3 Army Corps of Engineers

Officially a branch of the military, fully 80% of the works performed by the ACE represent civilian

efforts.3

 They manage an intracoastal and inland network of 12,000 miles of commercial navigation

channels. They also operate more than 200 locks and dams for navigation. More than two billion tons

of commerce are moved on these waterways annually. The ACE also operates 368 reservoirs for flood

control, from which one fourth of the nation's hydropower is produced. The $20 billion investment in

flood control during the 1990s was credited with the prevention of $168 billion in flood damage. One of

the means they employ to support this widespread network of facilities throughout the US are point-topoint microwave communications systems. ACE maintains 346 permanent frequency assignments

within the 1755 to 1850 MHz band to support these operations. ACE operations in this band represent

approximately one-half of the DoD fixed point-to-point microwave system operations that are

authorized in this band by permanent frequency assignment.

E.1.3.1 Operational Mission Overview

ACE operates a nationwide system of fixed point-to-point microwave links providing connectivity for

monitoring water levels, remote alarms, and communications for remote locks, dams, and other water

systems. This system provides microwave links where no commercial communications connectivity

exists. This system is essential to ACE operations because it allows for remote monitoring of critical

waterway operations negating the need for full time, on-site personnel. The systems provide key

maintenance parameters, alarm indications, and provide personnel at the facility with communications

capability. The system helps ensure the safety and integrity of the nation’s waterways and helps prevent

catastrophic events that could cost lives and economic damage as well as environmental damage.

ACE employs fixed point-to-point microwave communications systems to accomplish a number of

functions in CONUS. Information provided within permanent frequency assignments recorded for these

operations indicate their majority support backbone communications; the remainder support civil works,

miscellaneous microwave, administrative, energy control and utilities, hydrologic, survey, construction,

and contingency functions. Additional information indicates these assignments support remote

hydropower and ship-traffic control, and ACE inter-district voice and data connections. Several indicate

they were coordinated with the Department of Energy (DOE). The CONUS region that is most densely

populated with ACE operations is the Mississippi River basin. The second and third most densely

 

3

 “US Army Corps of Engineers Home Page,” [USACE Web Page], Washington, DC: USACE, 12 December 2000

[cited 19 December 2000]. Available from http://www.usace.army.mil/; INTERNET.
DoD IMT-2000 Assessment

E-5

populated regions include the Sierra Nevada and Northern Coastal Ranges in California, and the

Columbia Plateau in Washington, respectively. Locations where the ACE is authorized by permanent

frequency assignment to employ fixed point-to-point microwave systems in CONUS are depicted in

Figure E-2.

Figure E-2. Army Corps of Engineers 1755 to 1850 MHz Point-to-Point

Communications Locations

E.1.3.2 Technical Assessment

Sharing between fixed ACE point-to-point microwave and IMT-2000 systems was determined on a oneto-one basis. Distances beyond which compatible operations of these systems could be attained were

calculated for all receiver and transmitter pairings. IMT-2000 base and mobile configurations were

assessed. The fixed point-to-point microwave antenna and IMT-2000 base station antennas were all

assessed as having a two-step antenna pattern comprised of mainbeam and median gain levels.

Fully 90% of the fixed ACE point-to-point microwave communications systems are manufactured by

the Motorola Corporation and Granger Associates. The Motorola K16RBF, Motorola K26RBF,

Granger 6015-AE, and Granger 6018A microwave systems constitute the majority of these systems. Of

these four, the technical characteristics of the Granger 6015-AE were deemed representative of the

median system characteristics identified in permanent frequency assignment data for all ACE systems.

The characteristics of this system are identified in Table E-2. The interference threshold for this system,

an I/N level of –6dB, was based on ITU-R F.1334, which limits the degradation due to interference in a

fixed service receiver to +1 dB.
DoD IMT-2000 Assessment

E-6

Table E-2. ACE Fixed Point-to-Point Microwave Characteristics4, 5

Frequency Range 1700 to 1850 MHz

Mean Power 10 watts

Emission Designator 2M17F8E

Emission Bandwidth (MHz) 0.5 (-3 dB), 1.8 (-20 dB), 2.9 (-40 dB), and 4.0 (-60 dB)

IF Bandwidth (MHz) 4.5 (-3dB), 7.0 (-20 dB), and 25 (-60 dB)

Receiver Noise Figure 7 dB

Receiver Sensitivity -94 dBm (30 dB S/N)

Receiver Noise Power -108 dBm

Transmission Capacity 72 channels

Transmit/Receive Spacing 20 MHz

Antenna Gain 29 dBi (Mainbeam); -6 dBi (>30 degrees off-axis)

Antenna Height 80 m

The technical parameters for the IMT-2000 radios are presented elsewhere in this report. The IMT-2000

receiver thresholds were modified in the same manner described in the Tactical Radio Relay Assessment

of Interference.

As was done in previous sections, an assessment was performed to quantify the distance separation at

which compatible on-tune operations of fixed point-to-point microwave and IMT-2000 systems would

exist. The necessary propagation loss to ensure compatible operations for mainbeam (MB) and median

sidelobe (SL) antenna-to-antenna couplings was calculated by summing the corresponding transmitter

power, transmitter and receiver antenna gain, and frequency dependent rejection. The corresponding

receiver interference threshold was subtracted from this value to ascertain the minimum propagation

path loss at which compatible operations would exist. Next, the Spherical Earth Model (SEM) was

employed to calculate the distance separation between transmitter and receiver antennas, which would

produce the minimum propagation path loss for the corresponding transmitter and receiver antenna pair.

Lastly, the frequency dependent rejection term was varied to introduce effects relating to off-tuned

operations of the two systems. The IMT-2000 (transmitter) to fixed point-to-point microwave (receiver)

distance separation values beyond which compatible operations would exist are contained in Table E-3.

The fixed point-to-point microwave (tranmitter) to IMT-2000 (receiver) distance separation values

beyond which compatible operations would exist are contained in Table E-4.

 

4 Granger Model 6015-3A/E/72 Microwave Terminal, Application for Equipment Frequency Allocation (DD Form

1494) J/F 12/5441,14 September 1984.

5

 Manufacturer’s Brochure, 1800 MHz Terminals – Model 6015/AE, Santa Clara, CA: Granger Associates, n.d.
DoD IMT-2000 Assessment

E-7

Table E-3. IMT-2000 Transmitter to Fixed Point-to-Point Microwave Receiver Distance

Separations Beyond Which Compatible Operations Would Exist

Transmitter-to-Receiver Coupling Distance Separation for Compatible Operations (km)

IMT-2000 6015-AE CDMA(NB) CDMA(WB) ISM-136 GSM

Base MB MB 131 131 131 131

Base MB SL 71 71 71 71

Base SL MB 91 91 91 91

Base SL SL 59 59 59 59

Mobile MB 41 41 41 41

Mobile SL 11 11 11 11

Table E-4. Fixed Point-to-Point Microwave Transmitter to IMT-2000 Receiver Distance

Separations Beyond Which Compatible Operations Would Exist

Transmitter-to-Receiver Coupling Distance Separation for Compatible Operations (km)

6015-AE IMT-2000 CDMA(NB) CDMA(WB) ISM-136 GSM

MB Base MB 160 137 178 178

MB Base SL 105 94 115 115

MB Mobile 62 58 64 64

SL Base MB 76 72 79 79

SL Base SL 64 60 67 67

SL Mobile 29 25 32 32

A review of the results in these two tables yields several interesting findings. The separation distances

of most consequence are tied to operations of the fixed point-to-point microwave system. Irrespective of

the IMT-2000 system, larger distance separations are required for compatible operations of both system

classes in all cases of antenna coupling from the 6015-AE transmitter but for the lone exception

involving the mainbeam of the 6015-AE receiver. Thus, the technical characteristics of fixed-point-topoint microwave systems will dictate the minimum distance at which compatible operations will exist.

Lastly, simultaneous on-tune operations of both system classes are not projected to be compatible

without significant distance separation.

The employment of frequency separation will surely decrease the distance separations at which

compatible operations could exist. It will not, however, enable both classes of systems to operate

without some form of coordination between their fixed operations. Given the modeling of the

transmitter and receiver bandwidth characteristic fall-off curves below –60 dB, the maximum

attenuation realizable for a frequency separation of 95 MHz is on the order of -73 dB. This amount of

attenuation is more than sufficient to decrease the required separation distance values for compatible

operations cases involving sidelobe coupling between directional antennas and omnidirectional mobile
DoD IMT-2000 Assessment

E-8

antennas below 3 km. For mainbeam-to-mainbeam coupling between directional antennas, however, it

is not sufficient to decrease the required separation distance values much below 25 km.

E.1.3.2.1 Results Option 1 – Full Band Sharing. A frequency separation on the order of 5 MHz

would decrease the required separation to approximately 10 km for transmitter to receiver couplings

between the 6015-AE mainbeam and mobile IMT-2000 systems. A frequency separation between 25

and 30 MHz would decrease the required distance separation between a 6015-AE and an IMT-2000 base

station to approximately 10 km, given mainbeam-to-sidelobe coupling. While these separations in

distance and frequency are not prohibitive, their significance will depend on the proliferation of IMT2000 devices in regions where fixed-point-to-point microwave antennas are located. It may not be

practical to continue operations of ACE point-to-point microwave systems along the populated portions

of the Mississippi River, but the converse might prove true along the Columbia plateau or along the

Sierra Nevada Range.

Since the microwave links tend to be in remote areas, sharing should not present a problem. For those

links near population centers or IMT-2000 systems, frequency sharing could be coordinated; otherwise

the link will have to be relocated in the spectrum.

E.1.3.2.2 Results Option 2 – Band Segmentation/Partial Band Sharing. Fixed point-topoint communications systems could, most likely, coexist in the 1755 to 1850 MHz band, if larger

segments of the band were retained on an exclusive basis. Retention of these segments on a shared basis

is less feasible. Irrespective of how the band is shared, the concerns involving frequency separation,

outlined in Option 1, Full Band Sharing, must still be addressed. The simultaneous operations of fixed

point-to-point microwave systems and IMT-2000 base stations would have to be coordinated on a oneon-one basis to preclude interference effects.

Consideration must be given to the microwave system requirement that distinct transmit and receive

frequencies are required for each point-to-point link. These frequencies are typically separated by 20 to

50 MHz, as denoted in Table E-1. Segments to be retained must accommodate this channel separation

requirement. They must also accommodate multiple transmit and receive links at sites where more than

two microwave systems are in use.

Additionally, the permanent frequency assignments for a significant number of 1755 to 1850 MHz ACE

links denote their second frequency lies within the 1710 to 1755 MHz band. While this lower band

segment was reallocated in accordance with OBRA-93, it has yet to be reassigned, and the former

population of users has been allowed to retain use of their assignments until the 1710 to 1755 MHz band
DoD IMT-2000 Assessment

E-9

is reassigned. Band segments to be retained must also accommodate the pending loss of assignments in

the lower adjacent band.

Of final note, most of the 1710 to 1855 MHz fixed point-to-point microwave systems in use today are

legacy equipment from the 1970s and 1980s. Crystal oscillators and other components that may be

required to retune their transmit and receive frequencies might not be commercially available any more.

Band segmentation is acceptable as long as the microwave system is capable of operating in that portion

of the band.

E.1.3.2.3 Results Option 3 – Partial Band Segmentation/Other Band Combination (if

viable). In a variation of Option 2, Band Segmentation/Partial Band Sharing, an opportunity does exist

to employ spectrum between 1700 and 1710 MHz. This segment is currently allocated to the

Government Fixed and Meteorological-Satellite (space-to-Earth) Services on a shared basis with similar

Nongovernment services. By footnote (G118), Government fixed stations may be authorized in the

1700 to 1710 MHz band only if spectrum is not available in the 1710 to 1850 MHz band. It is likely this

small segment of spectrum could be employed to accommodate displaced users of the 1710 to

1850 MHz bands, who could not readily be accommodated in band segments that are retained on an

exclusive or shared basis between 1755 and 1850 MHz.

Additional issues are similar to those discussed under Results for Option 2.

E.1.3.2.4 Results Option 4 – Vacate 1755-1850 MHz. A significant amount of frequency

spectrum is already allocated to the Government on an exclusive basis for Fixed Service operations in

higher frequency ranges. The 4400 to 4990 MHz and 7125 to 8500 MHz bands are already employed

by the DoD for fixed point-to-point microwave communications in CONUS. The median 1755 to 1850

MHz ACE point-to-point link length is 40 km. Fully 84% of these links are less than 64 km in length.

Based on engineering judgement, point-to-point microwave equipment from the two alternate bands

could replace existing 1710 to 1850 MHz equipment without the installation of additional antenna

towers for links of 64 km or less in length. The remainder, whose length is between 64 and 120 km, are

potentially long enough to require the installation of an additional antenna to complete the link. A scan

of permanent frequency assignments for the 4400 to 4990 MHz band indicates all three DoD services

employ the Terra-Com TCM-602 and TCM-620. A similar scan of the 7125 to 8500 MHz band

indicates the DoD employs the Terra-Com TCM-604 (Air Force, Army, and Navy), Collins MW-518

(Air Force, Army, and Navy), Collins MDR-8-5N (Air Force), and the Alcatel MDR-4308 (Air Force

and Navy). Much like the equipment DoD already employs in the 1755 to 1850 MHz band, most are
DoD IMT-2000 Assessment

E-10

legacy equipment from the 1970s and 1980s. A quick search of point-to-point microwave equipment,

whose form and functions might suffice as replacement equipment, indicates the systems identified in

Table E-5 are commercially available today. Lastly, consideration should also be given to the

replacement of RF-based links with cable-based links. The use of fiber optic cable might prove to be a

viable alternative for replacement of RF links in less remote regions of the CONUS.

Table E-5. Commercially Available Point-to-Point Microwave Equipment

(commercial brochures and web pages)

Corporation Model Frequency Range Purpose

Harris Corporation ConstellationTM 7125 to 8275 MHz Point-to-Point Digital

Alcatel 9647LH 4400 to 5000 MHz Long Haul Digital Links

9674LH 7125 to 7700 MHz Long Haul Digital Links

9681LH 7700 to 8400 MHz Long Haul Digital Links

MDR-6X07/08 7125 to 8500 MHz Long Haul/Low Capacity

MDR-4X05 4500 to 5000 MHz Medium Capacity Digital

MDR-4X08 7100 to 8500 MHz Medium Capacity Digital

Vacating the band is an unnecessary option unless sharing or segmentation does not work. This should

apply to individual links and not the microwave system as a whole. Those links situated in a high

density IMT-2000 environment may need to be relocated in the spectrum. During any relocation, the

current link must be kept operational until the new link is ready for cutover, to prevent remote facilities

from being unmonitored.

E.2 POTENTIAL FOR INTERFERENCE TO AND FROM LAND WARRIOR

Land Warrior is a twenty-first century fighting system for military operations in urban terrain. Under

development since 1991 by the US Army and Marine Corps, this system will integrate digital

technologies into dismounted forward combat troops at the squad, platoon, and company level. Land

Warrior incorporates advanced weaponry, communications, and intelligence systems into a composite,

soldier-based fighting system. The primary subsystems include the M-16/M-4 Modular Carbine,

integrated helmet assembly, protective clothing and integrated equipment, computer/radio, and software.

The Land Warrior Wireless Local Area Network (WLAN) is designated as the communications portion

of this system. A pre-production version of the system was successfully demonstrated in calendar year

2000; production quantities of Land Warrior are scheduled for delivery starting in calendar year 2003.
DoD IMT-2000 Assessment

E-11

E.2.1 Operational Mission Overview

Land Warrior represents the next generation of combat capability for the soldier. The Land Warrior

system is a close combat fighting system for infantrymen, combat medics, combat engineers, forward

observers, and scouts. As a system, the soldier can both send and receive voice, video images, map

overlay information, operational plan diagrams, etc. The system also provides situation awareness (SA)

information among all team members, improves survivability, and increases lethality while reducing the

soldier’s load. The current maneuver forces have no such capability today at the lowest echelons.

Land Warrior is designed to enhance the ‘situational awareness’ of dismounted troops. Currently, this is

accomplished through voice communications or hand signals. Land Warrior will supplement ordinary

voice communications with video imagery and data transmissions. The resultant combination of

communications capabilities will enable the squad leader to monitor troop progress and mission success.

Conversely, Land Warrior will offer troops the capability to receive information formerly available to

the squad leader alone. The Land Warrior WLAN is the sole communications subsystem through which

all voice, data , and video imagery will be transmitted and received.

E.2.2 System Descriptions

The technical characteristics of the Land Warrior WLAN are identified in Table E-6. One parameter

bears additional discussion. The LAN is basically a commercial-off-the-shelf item. The key difference

is that its baseband has been downconverted to the 1750 to 1850 MHz band. The IEEE 802.11

channelization scheme it employs was devised to support direct-sequence spread spectrum wireless

telephony in the 2400 to 2483.5 MHz industrial, scientific, and medical (ISM) band. These operations

are type-certified in accordance with FCC Part 15. Eleven channels, spaced at 5-MHz intervals,

constitute this channel plan between 2412 and 2462 MHz.6

 The frequency range of the downconverted

Land Warrior WLAN channel plan lies between 1772 and 1822 MHz. In accordance with IEEE 802.11,

a diphase binary phase-shift keyed modulation is applied with an 11-megachip per second chipping rate

and a 1-megabit per second (Mb/s) bit rate. In practice, no more than three channels are available for

use in close proximity to one another and the channel throughput is reduced from 11 Mb/s to something

on the order between 2 and 5 Mb/s.7

 

6 “The IEEE 802.11 Wireless LAN Standard” [The Wireless LAN Association Web Page], Willoughby, OH, 2000 [cited

4 December 2000]. Available from http://www.wlana.com/learn/; INTERNET.

7

 J. Conover, “Wireless LANS Work Their Magic” [Network Computing – The Technology Solution Center Web Page],

CMP Media, Incorporated, 10 July 2000 [cited 21 December 2000]. Available from

http://www.networkcomputing.com/1113/1113f2.html; INTERNET.
DoD IMT-2000 Assessment

E-12

Table E-6. Land Warrior WLAN Characteristics8

Frequency Range: 1750 to 1850 MHz

Mean Power: 2 watts

Emission Designator 20M0G9W

Emission Bandwidth (MHz) 10 (-3 dB), 20 (-20 dB), 35 (-40 dB), and 40 (-60 dB)

IF Bandwidth (MHz): 17 (-3dB), and 35 (-60 dB)

Receiver Noise Figure 7 dB

Receiver Sensitivity -100 dBm (30 dB S/N)

Receiver Noise Power -103 dBm

System Capacity: 11 overlapped channels (IEEE 802.11 channelization)

Antenna Gain: 6 dBi (Omnidirectional)

Antenna Height 1.5 m

E.2.3 Technical Assessment

Sharing between the Land Warrior WLAN and IMT-2000 systems was determined on a one-to-one

basis. Distances beyond which compatible operations of these systems could be attained were

calculated for all receiver and transmitter pairings. IMT-2000 base and mobile configurations were

assessed. The IMT-2000 base station antennas was assessed as having a two-step antenna pattern

comprised of mainbeam and median gain levels. The Land Warrior WLAN and IMT-2000 mobile

station antennas were both assessed as having an omnidirectional antenna pattern.

The technical parameters for the IMT-2000 radios are presented elsewhere in this report. The IMT-2000

receiver thresholds were modified in the same manner described in the Tactical Radio Relay Assessment

of Interference.

As was done in previous sections, an assessment was performed to quantify the distance separation at

which compatible on-tune operations of the Land Warrior WLAN and IMT-2000 systems would exist.

The necessary propagation loss to ensure compatible operations for mainbeam (MB) and median

sidelobe (SL) antenna-to-antenna couplings was calculated by summing the corresponding transmitter

power, transmitter and receiver antenna gain, and frequency dependent rejection. The corresponding

receiver interference threshold was subtracted from this value to ascertain the minimum propagation

path loss at which compatible operations would exist. Next, the Spherical Earth Model (SEM) was

employed to calculate the distance separation between transmitter and receiver antennas, which would

produce the minimum propagation path loss for the corresponding transmitter and receiver antenna pair.

 

8 Land Warrior WLAN, Application for Equipment Frequency Allocation (DD Form 1494) J/F 12/7786, October 2000.
DoD IMT-2000 Assessment

E-13

Lastly, the frequency dependent rejection term was varied to introduce effects relating to off-tuned

operations of the two systems. The IMT-2000 (transmitter) to Land Warrior WLAN (receiver) distance

separation values beyond which compatible operations would exist are contained in Table E-7. The

Land Warrior WLAN (transmitter) to IMT-2000 (receiver) distance separation values beyond which

compatible operations would exist are contained in Table E-8.

Table E-7. IMT-2000 Transmitter to Land Warrior WLAN Receiver Distance Separations

Beyond Which Compatible Operations Would Exist

Transmitter-to-Receiver Coupling Distance Separation for Compatible Operations (km)

IMT-2000 Land Warrior WLAN CDMA(NB) CDMA(WB) ISM-136 GSM

Base MB Mobile 38 38 38 38

Base SL Mobile 28 28 28 28

Mobile Mobile 2.5 2.5 2.5 2.5

Table E-8. Land Warrior WLAN Transmitter to IMT-2000 Receiver Distance Separations

Beyond Which Compatible Operations Would Exist

Transmitter-to-Receiver Coupling Distance Separation for Compatible Operations (km)

Land Warrior WLAN IMT-2000 CDMA(NB) CDMA(WB) ISM-136 GSM

Mobile Base MB 34 34 34 34

Mobile Base SL 23 23 23 23

Mobile Mobile 5 5 5 5

The employment of frequency separation does reduce the distance separations beyond which compatible

operations of the two systems would exist, albeit not very much. Table E-9 contains several discrete

combinations of frequency and distance separation which would ensure compatible simultaneous

operations. Note: the separations contained in Table E-9 pertain to the transmitter/receiver pairings

which require the furthest separations. A review of the data indicates IMT-2000 base stations could not

operate in close proximity to ranges where the Land Warrior WLAN is to be employed without prior

frequency planning and coordination. Whereas off-frequency tuning will decrease the separation

distance beyond which the two mobile stations could operate compatibly, its effects are minimal.

However, on-tune operations of IMT-2000 mobile stations should be of little consequence to Land

Warrior operations provided these two systems are separated by a small distance.
DoD IMT-2000 Assessment

E-14

Table E-9. Frequency and Distance Separations Beyond Which Simultaneous Operations of the

Land Warrior WLAN and IMT-2000 Would Exist

Frequency Separation Distance Separation (km)

(MHz) Base MB Base SL Mobile

0.0 38 27 5

4.5 38 27 4.5

5.0 38 27 4.1

6.0 38 27 3.1

7.0 38 27 2.5

8.0 38 26 2.4

9.0 32 22 1.7

10.0 25 16 1.5

15.0 6 2.0 0.6

20.0 2.4 0.5 0.2

E.2.3.1 Results Option 1 – Full Band sharing

Simultaneous on-tune operations of IMT-2000 and the Land Warrior WLAN might be practicable if

certain geographic constraints can be established. IMT-2000 base stations must not be installed within

40 km of the perimeter of military test and training facilities where Land Warrior WLAN operations will

be authorized. The likelihood this requirement could be fulfilled is reasonable. Additionally, IMT-2000

connectivity must be prohibited within the confines of these same facilities. The likelihood this

requirement could be fulfilled is far from certain as it may be impossible to police such a prohibition.

While potentially practicable, full band sharing poses too much risk.

Potential risk mitigation techniques applicable to full or partial band sharing would require the Army, in

conjunction with the IMT-2000 industry, to develop acceptable frequency use coordination procedures

and implement them in software in the Integrated System Control (ISYSCON) (used by tactical forces

during training and to coordinate sharing with line-of-sight (LOS) radio networks) and Spectrum XXI

(for use by Army frequency managers to work frequency assignments). Although this option appears

attractive, the restrictions for sharing, such as limiting operations, locations, and link length, may inhibit

the full use of this system by the Army. The restrictions may end up being unworkable at some

locations and would require software supportability through ISYSCON and Spectrum XXI. If the Army

wants to train as it fights, limiting the size and scope of the training exercises is counterproductive.

Large-scale maneuver of forces for training is already limited to specific locations. Also, Army Guard

and Reserve unit training at home locations will be similarly affected.
DoD IMT-2000 Assessment

E-15

E.2.3.2 Results Option 2 – Band segmentation/partial band sharing

Simultaneous operations of IMT-2000 and the Land Warrior WLAN in segregated portions of spectrum

are more practicable than full band sharing. The amount of frequency separation that will be required to

ensure compatible operations will depend on the relative location where Land Warrior WLAN

operations are authorized. If the location of these operations is well within the perimeter of a military

test or training facility, no further coordination would be required; otherwise, some form of coordination

may be required to ensure IMT-2000 base station operations do not pose conflicts. No matter the

location, IMT-2000 mobile operations must still be prohibited within the immediate vicinity of the area

where Land Warrior WLAN operations are authorized.

One requirement that must still be addressed is the number of Land Warrior WLAN channels that will

be required to support a given test or exercise. As was stated previously, no more than three Institute of

Electrical and Electronics Engineers (IEEE) 802.11 channels are available for collocated use irrespective

of band segmentation. The implementation of band segmentation could further reduce the number of

available channels such that the full capability of the Land Warrior WLAN is unattainable during test

and training operations. The likelihood that multiple Land Warrior WLANs will be required to operate

in the same environment must be ascertained.

The 50-MHz block would give the current Land Warrior radio reduced room to operate and will

continue to require close frequency coordination in ISYSCON and Spectrum XXI for sharing the band

with LOS radio networks.

E.2.3.3 Results Option 3 – Partial band segmentation/Other band combination (if viable)

The current design of the Land Warrior WLAN is such that it is only capable of tuning within the 1772

to 1822 MHz sub-band. Given the current system design, it would not be possible to combine the use of

band segments in adjacent spectrum with band segments in the 1755 to 1850 MHz to fulfill Land

Warrior WLAN operational requirements.

This option frees up 10 MHz more, but the same restrictions and coordination issues apply. See

Option 2.
DoD IMT-2000 Assessment

E-16

E.2.3.4 Results Option 4 – Vacate 1755-1850 MHz

The current Land Warrior WLAN frequency band is a compromise between competing requirements.

The band must support omnidirectional connectivity between soldiers. Spectrum below 2000 MHz most

readily accommodates this requirement without the use of complicated antenna arrays. Such arrays

would be prohibitively difficult to integrate into the vest that houses the bulk of the Land Warrior

system on the warfighter’s body. The use of spectrum below 1000 MHz would pose a similar difficulty

as the antenna size would be too large to integrate effectively and factors associated with body loading

would be a concern. To minimize development costs and risk, a choice was made to employ a

commercial-off-the-shelf (COTS) RF assembly as the heart of the baseband local area network (LAN)

system. Initially designed to operate in the 2400 to 2483.5 MHz band, the frequency band of this

assembly is downconverted to reach the 1755 to 1850 MHz band. System weight is already nearing its

maximum level. No more batteries can be integrated without surpassing the Land Warrior system

weight requirement, yet power remains to be a concern as the LAN subsystem just meets its range

requirement of 1.3 kilometers. The resultant choice of Government exclusive spectrum between 1755

and 1850 MHz successfully fulfilled the majority of these system requirements.

Little spectrum exists between 1000 and 2000 MHz to accommodate the Government Mobile Services

on a primary or secondary basis. Excluded through recent or pending reallocation initiatives in

accordance with OBRA-93 mandates are 1427 to 1429 MHz, and 1710 to 1755 MHz. Included are 1350

to 1400 MHz, 1432 to 1435 MHz, and 1435 to 1535 MHz.

The 1350 to 1400 MHz band is allocated to the Government Mobile Services on a primary basis

between 1350 and 1390 MHz and on a secondary basis between 1390 and 1400 MHz. Both

domestically and internationally, spectrum in the lower and upper adjacent bands is not allocated to

accommodate the Mobile Services on any basis.

Thus, there is insufficient spectrum to accommodate all eleven channels of the COTS baseband RF

assembly. As was discussed under band segmentation options, no more than three of eleven IEEE

802.11 channels are available for collocated use given the full operational band is available for use. The

use of any sub-band could further reduce the number of available channels even further. The full

capability of the Land Warrior system might be unattainable if multiple Land Warrior WLAN nets are

required to operate in the same environment simultaneously.

The 1432 to 1435 MHz is much too small in bandwidth to accommodate a single Land Warrior WLAN

channel.
DoD IMT-2000 Assessment

E-17

The 1435 to 1535 MHz band is allocated to the Government Mobile Services on a primary basis

between 1435 and 1525 MHz and on a secondary basis between 1525 and 1535 MHz. Unfortunately,

aeronautical telemetry (ATM) is the only Mobile Service authorized in these band segments. In

accordance with US footnote 78 (US 78), the frequencies between 1435 and 1535 MHz will be assigned

for ATM and associated telecommand operations for flight testing of manned or unmanned aircraft and

missiles, or their major components. Permissible usage is defined to include telemetry associated with

launching and reentry into the earth’s atmosphere as well as an incidental orbiting prior to reentry of

manned objects undergoing flight tests. The DoD test and evaluation (T&E) community has become

increasingly defensive of the spectrum that remains to support ATM operations in CONUS. They

contend their spectrum requirements will exceed the amount of spectrum allocated to their operations in

the next few years given the projected amount of data they expect to download during future single

aircraft and multiple-aircraft flight tests. Insufficient spectrum will result in increased aircraft

development program costs when testing schedules are slipped or stretched in duration. The allocation

status of this band must be satisfactorily addressed before any attempt is made to expand the existing

allocation to include the ground-based mobile services, even for an operation so low-powered and shortrange as the Land Warrior WLAN. On a more positive note, spectrum between 1427 and 1525 MHz is

allocated internationally to the Mobile Services on a primary basis, which would be conducive to Land

Warrior WLAN outside the continental US (OCONUS) operations.

Fully vacating the band is not acceptable for the Land Warrior, since it will require redesigning of the

radio. Depending upon the new band, this may have a severe impact on the ability of the system to meet

its required 1.3 km operating range (on open, flat, uncluttered terrain). However, if the Land Warrior

was forced to migrate to another portion of the spectrum, then the optimum plan/schedule for

implementing such a move is now. The system is fast paced and will be building 41,000 units beginning

in FY03. Any move decision would delay the schedule about six months. The radio and antenna will

have to be redesigned and system testing reaccomplished. Evolutionary growth of the system through

field testing will be interrupted if Land Warrior is forced to move to another band. The impact to

current operations is none, but the impact to our future soldiers is unknown at this time and requires

further study.

E.3 POTENTIAL FOR INTERFERENCE TO AND FROM CIDDS

Combat identification is the ability to differentiate friend, foe, or neutral, with high confidence, beyond

engagement range, and in sufficient time to support successful engagement and weapon release

decisions. Several means by which combat identification is performed include RF interrogation, laser

interrogation, and electronic surveillance measures. Dismounted ground-maneuver forces traditionally
DoD IMT-2000 Assessment

E-18

have employed vision-oriented means to perform combat identification. The range at which positive

identification can be reliably accomplished through visual means, relative to the range of the forces

weaponry, is considered to be marginal in daylight conditions and inadequate in darkness, foul weather,

or when vision is compromised by obscurants or smoke. The CIDDS system is being developed to

improve the ability of dismounted forces to aid in the determination of friendly and unfriendly

dismounted forces. An engineering and manufacturing development (E&MD) program since 1997, this

program will culminate in the delivery of fifty CIDDS units prior to the initiation of low-rate initial

production (LRIP). Current projections indicate as many as 100,000 CIDDS units will be procured at

the outset to full-scale production.9

E.3.1 Operational Mission Overview

The purpose of CIDDS is to help prevent friendly forces from firing on friendly forces, otherwise known

as fratricide. CIDDS represents a huge leap forward in reducing fratricide among our forces. CIDDS is

a laser interrogate, RF response system designed to provide identification of friendly forces by

individual and automatic weapons users to a range of 1000 meters or more, depending on visual

conditions. The system is used by forward combat forces, in both open terrain and urban areas. The

laser interrogation signal message identifies a set of random frequency channels for the transponder to

use in its response. The CIDDS is to be employed by combat, combat support, and combat service

support soldiers. The CIDDS will be used to supplement existing target identification procedures,

enhance Situational Awareness, and help prevent the attack of friendly soldiers which may have been

attacked under existing rules of engagement. The combination of existing target identification

techniques and CIDDS will reduce fratricide and increase soldier survivability. Fratricide represented a

not so insignificant portion of the combat deaths experienced in Operation DESERT STORM. Any

opportunity to reduce this potential loss of life is considered critical to the combatant commanders.

CIDDS is a secure laser interrogation and RF response system which will permit the warfighter to

ascertain whether a targeted individual is friendly or unknown. In concert with existing visual-based

means, CIDDS will complement target identification procedures, but will not be employed as the sole

determinant for target identification. Warfighters from all three DoD services may eventually be

equipped with CIDDS to support a broad gamut of military operations. Employable as a stand-alone

capability or an integral capability within the Land Warrior System, CIDDS will fill a long-lasting

identification gap, and, it is hoped, increase survivability while reducing fratricide.

 

9

 “Combat ID Dismounted Soldier,” [USA PM CI Web Page], Ft Monmouth, NJ, August 2000 [cited 20 November

2000]. Available from http://peoiews.monmouth.army.mil/ci/; INTERNET.
DoD IMT-2000 Assessment

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E.3.2 System Descriptions

The CIDDS system has two major component groups.10 The weapon-mounted subsystem contains an

infrared (IR) laser interrogator, radio receiver, IR aiming laser, and Multiple Integrated Laser

Engagement System-compatible laser. The helmet-mounted subsystem contains laser detectors, flatpatch antennae, and a radio transmitter. When a soldier spots a target, he activates the CIDDS laser. The

laser interrogator directs its beam towards the unknown target. If the target is CIDDS-equipped (i.e.,

friendly), their helmet-mounted laser detectors will decode the interrogating signal, and enable an

encoded radio response from the CIDDS radio transmitter, thus identifying the target as friendly. The

helmet transmitter employs redundant transmissions on three frequencies to increase the probability of

identification.11 The combined interrogation and response time is less than one second. The

weapon-borne radio receiver of the interrogating soldier and the helmet-borne transmitter of the

responding soldier are the two CIDDS components which employ the 1755 to 1850 MHz band. The

weapon-borne receiver employs a directional receive antenna; the helmet-borne transmitter employs

four patch antennas whose combined coverage approximates an omnidirectional pattern. The technical

characteristics of CIDDS are identified in Table E-10.

Table E-10. CIDDS Characteristics

Frequency Range: 1755 to 1850 MHz

Mean Power: 1 watts

Emission Designator 37K8F1D

Emission Bandwidth (kHz) 19 (-3 dB), 53 (-20 dB), 161 (-40 dB), and 506 (-60 dB)

IF Bandwidth (kHz): 25 (-3dB), 150 (-20dB), and 500 (-60 dB)

Receiver Noise Figure 7 dB

Receiver Sensitivity -108 dBm (0.01 bit error rate; 16 dB S/N)

Receiver Noise Power -129 dBm

Channelization: From 1755.0125 MHz in 25 kHz increments

Antenna Gain (transmit): +2 dBi

Antenna Gain (receive): +6 dBi (mainbeam); –3 dBi (sidelobe)

Antenna Height 1.5 m

 

10 “Combat Identification Systems” [Motorola Corporation Integrated Systems Division Web Page], Scottsdale, AZ,

2000 [cited 27 December 2000]. Available from http://www.motorola.com/GSS/SSTG/ISD/ws/cidds.html; INTERNET.

11 Combat Identification for the Dismounted Soldier, Application for Equipment Frequency Allocation (DD Form 1494)

J/F 12/7554, 12 August 1998.
DoD IMT-2000 Assessment

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E.3.3 Technical Assessment

Sharing between CIDDS and IMT-2000 systems was determined on a one-to-one basis. Distances

beyond which compatible operations of these systems could be attained were calculated for all receiver

and transmitter pairings. IMT-2000 base and mobile configurations were assessed. The IMT-2000 base

station antennas were assessed as having a two-step antenna pattern comprised of mainbeam and median

gain levels. The CIDDS helmet-borne transmit antenna and IMT-2000 mobile station antennas were

both assessed as having omnidirectional antenna patterns. The CIDDS weapon-borne receive antenna

was modeled as having a two-step antenna pattern due to reflect its directionality.

The technical parameters for the IMT-2000 radios are presented elsewhere in this report. The IMT-2000

receiver thresholds were modified in the same manner described in the Tactical Radio Relay assessment

of interference.

As was done in previous sections, an assessment was performed to quantify the distance separation at

which compatible on-tune operations of CIDDS and IMT-2000 systems would exist. The necessary

propagation loss to ensure compatible operations for mainbeam (MB) and median sidelobe (SL)

antenna-to-antenna couplings was calculated by summing the corresponding transmitter power,

transmitter and receiver antenna gain, and frequency dependent rejection. The corresponding receiver

interference threshold was subtracted from this value to ascertain the minimum propagation path loss at

which compatible operations would exist. Next, the Spherical Earth Model (SEM) was employed to

calculate the distance separation between transmitter and receiver antennas, which would produce the

minimum propagation path loss for the corresponding transmitter and receiver antenna pair. Lastly, the

frequency dependent rejection term was varied to introduce effects relating to off-tuned operations of the

two systems. The IMT-2000 (transmitter) to CIDDS (receiver) distance separation values beyond which

compatible operations would exist are contained in Table E-11. The CIDDS (transmitter) to IMT-2000

(receiver) distance separation values beyond which compatible operations would exist are contained in

Table E-12.
DoD IMT-2000 Assessment

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Table E-11. IMT-2000 Transmitter to CIDDS Receiver Distance Separations Beyond Which

Compatible Operations Would Exist

Transmitter-to-Receiver Coupling Distance Separation for Compatible Operations (km)

IMT-2000 CIDDS CDMA(NB) CDMA(WB) ISM-136 GSM

Base MB Mobile MB 48 44 60 55

Base SL Mobile MB 36 32 50 44

Mobile Mobile MB 5 4 10 7

Base MB Mobile SL 40 36 53 48

Base SL Mobile SL 28 25 42 36

Mobile Mobile SL 3 2 7 4

Table E-12. CIDDS Transmitter to IMT-2000 Receiver Distance Separations Beyond Which

Compatible Operations Would Exist

Transmitter-to-Receiver Coupling Distance Separation for Compatible Operations (km)

CIDDS IMT-2000 CDMA(NB) CDMA(WB) ISM-136 GSM

Mobile Base MB 36 32 51 43

Mobile Base SL 25 21 39 32

Mobile Mobile 6 4 12 9

The separation distances beyond which compatible on-tune operations will result are relatively large,

when compared to the assessment of Land Warrior WLAN compatibility, for all couplings involving

IMT-2000 base station operations. The distance separations beyond which compatible on-tune

operations of IMT-2000 mobile station and CIDDS will result are significantly less and appear to be

more readily attainable. Given these results, it appears unlikely that simultaneous on-tune operations

can be authorized without some form of prior geographic coordination.

The employment of frequency separation does reduce the distance separations beyond which compatible

operations of the two systems would exist. Table E-13 contains several discrete combinations of

frequency and distance separation which would ensure compatible simultaneous operations. Note: the

separations contained in Table E-13 pertain to the transmitter/receiver pairings which require the

furthest separations, irrespective of transmitter and receiver assignation as well as IMT-2000

modulation. No attempt was made to differentiate between the mainbeam and sidelobe gain levels of

the CIDDS receive antenna in Table E-13 as its beamwidth (60 degrees), coupled with its mobility, were

assumed representative of an omnidirectional antenna pattern in this summary of off-tuned results.
DoD IMT-2000 Assessment

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Table E-13. Frequency and Distance Separations Beyond Which Compatible Operations of

CIDDS and IMT-2000 Would Exist

Frequency Separation Distance Separation (km)

(MHz) Base MB Base SL Mobile

0.0 60 50 12

2.0 29 19 2.1

3.0 10 5 0.7

4.0 4.9 1.3 0.3

5.0 3.6 0.8 0.2

6.0 3.1 0.7 0.2

A review of the data indicates IMT-2000 base and mobile stations could not operate in close proximity

to ranges where CIDDS is to be employed without prior frequency planning and coordination.

However, frequency separation considerably decreases the separation distance beyond which the two

mobile stations could operate compatibly.

E.3.3.1 Results Option 1 – Full Band sharing

Simultaneous operations of IMT-2000 and CIDDS might be practicable if certain geographic or

frequency constraints can be established. For on-tune operations, IMT-2000 base stations must not be

installed within 60 km and IMT-2000 mobile stations must not be employed within 12 km of military

test and training facilities where CIDDS operations will be authorized. For off-tuned operations, these

distance requirements would be relaxed considerably although IMT-2000 connectivity must be

prohibited within several kilometers of CIDDS operating areas given frequency separations of several

megahertz. The likelihood either of these requirements could be fulfilled is far from certain as it may be

impossible to police a prohibition on IMT-2000 use on military bases. While potentially practicable,

full band sharing poses too much risk.

Full band sharing may be acceptable but would require the Army, in conjunction with the IMT-2000

industry, to develop acceptable frequency use coordination procedures and implement them in software

on the ISYSCON (for use by the tactical forces during training and to coordinate sharing with the line of

sight radio network) and Spectrum XXI (for use by Headquarters Army and installation spectrum

managers to work day-to-day issues). Some adaptation would be needed to the CIDDS system to ease

the frequency selection and assignment process. However, although this option looks attractive,

frequency use and location restrictions may inhibit the Army’s CIDDS training.

If the amount of frequencies available limits the size and scope of the training exercises, or if the

propagation restrictions forces limits where in the training ranges CIDDS can be used, this will reduce
DoD IMT-2000 Assessment

E-23

effective CIDDS training. Limiting operations, locations, link lengths, and size of the exercise would be

counterproductive to the purpose of the training. Large-scale maneuver of forces for training is already

limited to certain locations in the US. The major operational concern with this option is that if CIDDS is

limited to a single RF channel, it will affect performance and may actually increase the probability of

fratricide. CIDDS relies on frequency agility to decrease RF collisions and increase probability of

correct identification.

E.3.3.2 Results Option 2 – Band segmentation/partial band sharing

Simultaneous operations of IMT-2000 and CIDDS in segregated portions of spectrum are more

practicable than full band sharing. The amount of frequency separation that will be required to ensure

compatible operations will depend on the relative location where CIDDS operations are authorized. If

the location of these operations is well within the perimeter of a military test or training facility, little

further coordination would be required; otherwise, some form of coordination will be required to ensure

IMT-2000 base station operations do not pose conflicts. One unknown of this estimation is CIDDS

frequency reuse. Each CIDDS equipment requires three discrete relatively-narrow (38 kHz occupied

bandwidth) channels for response to interrogation. The total number of frequencies that will be required

to support a large-scale training exercise is unknown. Attempts to segment the 1755 to 1850 MHz band

to accommodate CIDDS operations must include consideration for the sum total spectrum required to

stage the operation as well as the upper and lower guardbands to ensure compatibility with IMT-2000

operations.

Partial band sharing would pose the same risks as full band sharing and are not recommended for

consideration for the same reasons.

The use of 50 MHz gives the current CIDDS radio some room to operate without having to shift bands

but will continue to require close frequency coordination in ISYSCON for sharing the band with LOS

radio networks. See Option 1.

E.3.3.3 Results Option 3 – Partial band segmentation/Other band combination (if viable)

The current design of CIDDS is such that it is only capable of tuning within the 1772 to 1822 MHz subband. Given the current system design, it would not be possible to combine the use of band segments in

adjacent spectrum with band segments in the 1755 to 1850 MHz to fulfill CIDDS operational

requirements.
DoD IMT-2000 Assessment

E-24

Additional issues are similar to those discussed under Results for Option 2.

E.3.3.4 Results Option 4 – Vacate 1755-1850 MHz

The current CIDDS frequency band is a compromise between competing requirements. The band must

support omnidirectional connectivity between soldiers, but must be capable of supporting the use of

small, weapon-borne, directional antennas for receipt of responses to laser interrogation. Spectrum

below 2000 MHz most readily accommodates omnidirectional connectivity. Spectrum above 1000 MHz

most readily accommodates the use of small, directional antennas. CIDDS must also be interoperable

with the combat identification capability of the Land Warrior system, which shares use of this band.

The resultant choice of Government exclusive spectrum between 1755 and 1850 MHz successfully

fulfilled the majority of these system requirements.

Little spectrum exists between 1000 and 2000 MHz to accommodate the Government Mobile Services

on a primary or secondary basis. Excluded through recent or pending reallocation initiatives in

accordance with OBRA-93 mandates are 1427 to 1429 MHz, and 1710 to 1755 MHz. Included are 1350

to 1400 MHz, 1432 to 1435 MHz, and 1435 to 1535 MHz.

The 1350 to 1400 MHz band is allocated to the Government Mobile Services on a primary basis

between 1350 and 1390 MHz and on a secondary basis between 1390 and 1400 MHz. The same tactical

radio-relay systems that operate in the 1755 to 1850 MHz band employ this band. Compatibility

concerns with these systems are considered doubtful for this reason. Fixed-frequency long-range

surveillance radars also employ this band, but conflicts with the aforementioned radio-relay operations

have already been deconflicted in CONUS and it is likely CIDDS equipment will be employed at the

same military training areas where radio-relay operations are authorized. Airborne target control and

range applications datalinks employ this band, too. While these systems are not electronically identical

to the weapons datalinks and air combat training systems in use in the 1755 to 1850 MHz band, their

operations are believed to be representative of one another and their collocated operations may prove

equally benign to one another. The one contrary note is that the 1350 to 1400 MHz band will not

support operations of the Land Warrior system with which CIDDS must be interoperable.

The 1432 to 1435 MHz band is not capable of adequately supporting CIDDS operations in providing

accuracy of correct identification (ID). The same radio relay and datalink systems whose operations

were addressed in the previous paragraph employ this band as well.
DoD IMT-2000 Assessment

E-25

The 1435 to 1535 MHz band is allocated to the Government Mobile Services on a primary basis

between 1435 and 1525 MHz and on a secondary basis between 1525 and 1535 MHz. Unfortunately,

aeronautical telemetry (ATM) is the only Mobile Service authorized in these band segments. In

accordance with US footnote 78 (US 78), the frequencies between 1435 and 1535 MHz will be assigned

for ATM and associated telecommand operations for flight testing of manned or unmanned aircraft and

missiles, or their major components. Permissible usage is defined to include telemetry associated with

launching and reentry into the earth’s atmosphere as well as an incidental orbiting prior to reentry of

manned objects undergoing flight tests. The DoD test and evaluation (T&E) community has become

increasingly defensive of the spectrum that remains to support ATM operations in CONUS. They

contend their spectrum requirements will exceed the amount of spectrum allocated to their operations in

the next few years given the projected amount of data they expect to download during future single

aircraft and multiple-aircraft flight tests. Insufficient spectrum will result in increased aircraft

development program costs when testing schedules are slipped or stretched in duration. The allocation

status of this band must be satisfactorily addressed before any attempt is made to expand the existing

allocation to include the ground-based mobile services, even for an operation so low-powered and shortrange as CIDDS. On a more positive note, spectrum between 1427 and 1525 MHz is allocated

internationally to the Mobile Services on a primary basis, which would be conducive to CIDDS

OCONUS operations.

Vacating the band will require a re-engineering effort on CIDDS, which is due to begin field testing in

Summer 2001. Delaying the deployment of CIDDS will increase the opportunity that our front line

soldiers will continue to fight without a fratricide prevention system.

E.4 POTENTIAL FOR INTERFERENCE BETWEEN IMT-2000 AND

UNMANNED AERIAL VEHICLES

A number of UAVs, such as the Pointer (FQM-151A) and the Exdrone (BQM-147A), currently use

spectrum between 1755 and 1850 MHz. These systems transmit video and status data from the UAV to

the GCS using analog FM video and data on subcarriers.

This section addresses the potential for interference between IMT-2000 base and mobile stations and the

UAV systems operating in the 1755 to 1850 MHz band, identifies possible electromagnetic interference

(EMI) interactions, and offers recommendations on how to obtain electromagnetic compatibility (EMC).

For this assessment, systems that operate within the 1350 to 1380, 2200 to 2290, and 4400 to 4940 MHz

frequency bands and are located within 200 nmi of China Lake were identified using the JSC Frequency
DoD IMT-2000 Assessment

E-26

Usage database. After compiling a complete listing of systems, the list was reduced to a number of key

systems. Mitigation techniques and interference link budget analyses were completed to determine if

the IMT-2000 systems operating in the 1755 to 1850 MHz band would interfere with the UAVs and to

determine if migrating the UAVs to a different frequency band, such as the 1350 to 1380, 2200 to 2290,

or 4400 to 4940 MHz band, would result in possible EMI.

E.4.1 Operational Mission Overview

The Pointer UAV is a production-ready, electric, hand launched UAV designed for remote monitoring

and surveillance. The 8.5 pound UAV transmits real-time video to the pilot and observer on the ground

as well as remote viewing stations, using a black and white color, or thermal cameras. A variety of

alternative payloads such as air pollution sensing, chemical weapons detection, and unexploded land

mine detection are currently being developed. The Pointer can carry a 1.5 pound payload and can

operate for 60 minutes on a non-rechargeable battery, or for 45 minutes with a rechargeable battery.

The Pointer has an operational range of 5-10 km.

E.4.2 System Descriptions

Characteristics of the FQM-151A and BQM-147A systems are identified in Tables E-14 and E-15. The

data values were obtained from the frequency allocation applications, unless noted otherwise.

Parameters of the BQM-147A downlink receiver were not available; however, the values were estimated

to be the same as those for the FQM-151A downlink receiver. For transmitter emission bandwidths and

receiver intermediate frequency (IF) bandwidths, as well as harmonic and spurious levels, the DD Form

1494 values were used instead of the specified values. The specified values represented a limit not to be

exceeded, while the 1494 values more closely represented actual system characteristics. The

BQM-147A specified, nominal maximum range is 50 km (31.1 mi, 27.0 nm), and the FQM-151A

communications range is 5 km (3.1 mi, 2.7 nm). The potential number of aerial vehicles in

simultaneous operation is three and five for BQM-147A and FQM-151A, respectively. Altitudes of

10,000 ft (3048 m) and 1,000 ft (305 m) were used for the BQM-147A and FQM-151A, respectively.

The IMT-2000 parameters used in the calculations are identified in Tables A-4 and A-5.
DoD IMT-2000 Assessment

E-27

Table E-14. BQM-147A and FQM-151A Airborne Transmitter Characteristics

Transmitter Characteristics

Platform BQM-147A FQM-151A

Frequencies in MHz 1755 – 1850 MHz 1737.5, 1787.5, and 1837.5 MHz

Power in W 10 1

Emission Bandwidth in MHz

-3 dB 3.0 8.7

-20 dB 15.0 19.9

-60 dB 29.1 40.7

Harmonic Attenuation in dB 65 55

Spurious Attenuation in dB 80 55

Antenna Characteristics

Type Yagi Dipole

Gain in dBi 2 2

Polarization V V

Height in ft 10,000 1,000

Table E-15. BQM-147A and FQM-151A Ground Receiver Characteristics

Receiver Characteristics

Platform BQM-147A FQM-151A

Sensitivity in dBm * -76 (20 dB S/N)

Noise Level in dBm * -96.0

RF Bandwidth in MHz

-3 dB * 150

-20 dB * 210

-60 dB * 280

1st IF Receiver Selectivity in MHz

-3 dB * 60

-20 dB * 90

-60 dB * 135

2nd IF Receiver Selectivity in MHz

-3 dB * 20

-20 dB * 24

-60 dB * 28

Spurious Response in dB * 60

Antenna Characteristics

Type Yagi Yagi

Gain in dBi 15 14

Polarization V V

Height in ft 6 6

* BQM-147A data not available, assumed identical to FQM-151A

E.4.3 Option 1 – Full Band Sharing

E.4.3.1 Technical Assessment

To analyze interference from IMT-2000 into BQM-147A and FQM-151A ground-based receivers, the

required separation distance to preclude interference into a ground receiver from a single IMT-2000 base
DoD IMT-2000 Assessment

E-28

and mobile transmitter was calculated. The BQM-147A and FQM-151A operational range is linkmargin limited. It was assumed that the maximum range between ground-based and airborne

equipment, which determines the maximum aircraft-to-aircraft separation, cannot be reduced by more

than ten percent due to interference from IMT-2000 systems. This condition equates to an allowed

degradation in the UAV link margins of approximately 1 dB and an I/N of -6 dB.

Interference between ground-based transmitters and receivers was calculated using Equation E-1:

I = PT + GT + GR – LP – LS – FDR (E-1)

where

I = interference power in receiver, in dBm

PT = transmitter power, in dBm

GT = transmitter antenna gain in direction of receiver, in dBi

GR = receiver antenna gain in direction of transmitter, in dBi

LP = propagation loss, in dB

LS = system losses, in dB

FDR = frequency-dependent rejection, in dB.

The interference power (I) was set to a maximum allowable value, the interference threshold It, which

for the BQM-147A and FQM-151A GCS receiver is 6 dB below the receiver noise level.

Equation E-1 was rearranged to:

LP = PT + GT + GR – LS – FDR – It (E-2)

where

LP = propagation loss, in dB

PT = transmitter power, in dBm

GT = transmitter antenna gain in direction of receiver, in dBi

GR = receiver antenna gain in direction of transmitter, in dBi

LS = system losses, in dB

FDR = frequency-dependent rejection, in dB

I = interference power in receiver, in dBm.
DoD IMT-2000 Assessment

E-29

Frequency-dependent rejection (FDR) for the on-tune cases considered here is given by Equation E-3:

FDR = 10 log (Bt/Br) for Bt > Br

0 for Bt ≤ Br (E-3)

where

Bt = transmitter 3-dB emission bandwidth, in Hertz

Br = highest-order intermediate frequency 3-dB receiver bandwidth, in Hertz.

The required separation distances to preclude interference between the IMT-2000 mobile and base

receivers verses the BQM-147A and FQM-151A airborne transmitters, and the BQM-147A and FQM151A GCS receivers verses the IMT-2000 mobile and base transmitters, were calculated using the

required propagation loss from Equation E-2 and the JSC Inverse Smooth Earth Model (ISEM).

Antenna heights used were: 40 m for the IMT-2000 base station transmitter and receiver, 1.5 m for the

IMT-2000 mobile transmitter and receiver, 2 m for the BQM-147A and FQM-151A receivers, 3048 m

for the BQM-147A transmitter, and 305 m for the FQM-151A transmitter.

E.4.3.2 Results

The required separation distances between the IMT-2000 mobile and base transmitters and the

BQM-147A, FQM-151A GCS receivers are given in Table E-16. The required separation distances

between the BQM-147A and FQM-151A airborne transmitters and the IMT-2000 mobile and base

receivers are given in Table E-17.

Table E-16. Distances, in km, from IMT-2000 Transmitters to Preclude Interference to BQM147A and FQM-151A GCS Receivers

Platform IMT-2000 Station

Mobile Base

BQM-147A 1.2 29.2

FQM-151A 1.2 28.4
DoD IMT-2000 Assessment

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Table E-17. Distances, in km, from BQM-147A and FQM-151A Airborne Transmitters to

Preclude Interference to IMT-2000 Receivers

IMT-2000 Station

Mobile Base

CDMA WB CDMA NB TDMA CDMA WB CDMA NB TDMA

Platform IMT-2000 Interference Criterion I/N = -6 dB

BQM-147A 236.2 235.8 222.3 269.5 270.2 260.9

FQM-151A 65.6 65.1 53.0 99.5 100.4 89.4

Platform IMT-2000 Interference Criterion for S = Sensitivity + 10 dB

BQM-147A 185.6 184.6 97.1 242.1 243.1 92.8

FQM-151A 30.1 29.6 9.7 32.6 35.3 9.3

Platform IMT-2000 Interference Criterion for S = Sensitivity + 20 dB

BQM-147A 107.7 162.5 30.6 102.9 111.5 29.2

FQM-151A 10.8 10.4 3.1 10.3 11.2 2.9

NB = Narrow Band

WB = Wide Band

I/N = Interference to Noise ratio

E.4.3.3 Operational Impact

Sharing would be acceptable and possibly workable but would require the Army, in conjunction with the

IMT-2000 industry, to develop frequency use coordinating procedures. There may some restrictions for

use that may limit the effectiveness of the system. Given the nature of the Pointer UAV and its concept

of operations for close in aerial surveillance, coordination with other civilian users seems possible.

E.4.4 Options 2 and 3 – Band Segmentation/Partial Band Sharing/Other

Band Combination

E.4.4.1 Technical Assessment

It was proposed to segment the current 1755 to 1850 MHz frequency band to allow concurrent

operations of the UAV systems and IMT-2000 equipment. In subsection E.4.3, the IMT-2000 and UAV

systems were assumed to be on-tune. Here, the 1755 to 1805 MHz portion of the band would remain

allocated to UAV systems, and either the 1805 to 1850 MHz or 1755-1790 MHz portion would be

allocated to the IMT-2000 systems.

E.4.4.2 Results

If the 1755 to 1850 MHz frequency band is segmented into adjacent bands, where one segment is strictly

allocated to the UAV systems and the other segment is allocated to the IMT-2000 systems, the effect of
DoD IMT-2000 Assessment

E-31

frequency separation between the two systems decreases the minimum required separation to preclude

EMI. With the reduction in bandwidth, only two BQM-147A and FQM-151A can operate

simultaneously. Use of two aerial vehicles will require channel spacing of at least 21 MHz, resulting in

minimal spectrum remaining for other systems. Frequency separation of at least 10 MHz and 14 MHz is

required between UAV systems and mobile and base stations, respectively, to achieve compatible IMT2000 operations.

Option three consisted of utilizing a portion of the 1755-1850 MHz frequency for shared IMT-2000 and

UAV use and utilizing a separate band for UAV use. The single air-to-ground data link mission can

only be accomplished in one contiguous band. Therefore, option three is not feasible.

E.4.4.3 Operational Impact

The 50 MHz would give the Pointer UAV video and telemetry space to operate without having to shift

bands. It will still require close frequency coordination for sharing the remaining portions of the band

with other DoD systems.

E.4.5 Option 4 – Vacate 1755-1850 MHz 

E.4.5.1 Migrating to the 1350-1390 MHz Frequency Band

The systems located within the electromagnetic environment (EME) are listed in Table E-18. The

analyzed 1350 to 1390 MHz systems are identified below.

Table E-18. Systems Located Within the EME

Nomenclature Number of systems

active

AN/GRC-226 7

AN/GRC-226 (V) 2

AN/GRC-50 10

AN/PPQ-2 3

AN/TPS-59 2

Gulf Range Drone Control

System (GRDCUS) 3

Nuclear Detonation Detection

System (NDS) 7

QUC101002 17

QUC1011002 1
DoD IMT-2000 Assessment

E-32

Table E-19 lists transmitter characteristics of primary 1350 to 1390 MHz systems, and Table E-20 lists

the receiver characteristics of the 1350 to 1390 MHz systems.

Table E-19. 1350-1390 MHz Systems Transmitter Characteristics

Transmitter Characteristics Antenna Characteristics

Emission Bandwidth

Platform (MHz) Frequency

(MHz) Power (W)

-3 dB -20 dB -60 dB

Gain (dB) Polarization

AN/FPS-108 NB 1175-1375 16.8 X 1065.0 10.0 200 47.9 V

AN/FPS-108 WB 1175-1375 16.8 X 106190 200 300 47.9 V

AN/FPS-117 NB 1215-1400 4 X 1030.625 0.8 4.6 39.1 V

AN/FPS-117 WB 1215-1400 4 X 1031.25 1.8 19.2 39.1 V

AN/FPS-124 1218-1398 700 3.0 19.0 597 30.9 V

AN/GRC-103 1350-1849 120 0.3 0.7 3.0 16 V

AN/GRC-226 1350-1850 5 1.0 2.0 6.0 20 V

AN/MRC-142 1350-1850 3 0.45 1.05 3.16 20.3 V

Air Route Surveillance

Radar (ARSR)

1215-1400 93 X 103 1.09 1.61 8.87 32 V

GPS L3 1350-1400 V

Multi-Object Tracking and

Control System (MTACS)

1350-1850 400 10.0 22.0 50.0 2.1 V

Table E-20. 1350-1390 MHz Systems Receiver Characteristics

Receiver Characteristics

RF Bandwidth (MHz) 1

st IF Receiver

Selectivity (MHz)

2

nd IF Receiver

Platform Selectivity (MHz)

Noise

Figure

(dB) -3 dB -20 dB -60 dB -3 dB -20 dB -60 dB -3 dB -20 dB -60 dB

Antenna

Gain

(dBi)

AN/FPS-108 NB 7 225 300 1000 68 90 137 18 47 121 47.9

AN/FPS-108 WB 7 225 300 1000 68 90 137 18 47 121 47.9

AN/FPS-117 NB 7 284 452 1350 20 40 120 20 40 120 39.7

AN/FPS-117 WB 7 284 452 1350 20 40 120 20 40 120 39.7

AN/FPS-124 7 218 303 630 10 32 320 2.4 6.4 12.3 30.2

AN/GRC-103 7 7 12 27 0.75 2.0 4.2 16

AN/GRC-226 7 30 45 110 0.85 2.0 6.0 20

AN/MRC-142 8 8.0 35 80 2.0 4.4 8.0 0.8 0.9 1.0 20.3

ARSR 7 58 71 121 0.69 1.9 5.3 0.69 1.9 5.3 32

GPS L3 7

MTACS 3.2 22 36 110 12 30 60 0

E.4.5.1.1 Technical Assessment. To analyze interference from the BQM-147A and FQM-151A

transmitters into incumbent 1350 to1390 MHz receivers, and interference from the incumbent 1350 to

1390 MHz transmitters into the BQM-147A and FQM-151A receivers, the required separation distances

to preclude interference were calculated. It was assumed that the incumbent 1350 to 1390 MHz

receivers, the BQM-147A receiver and the FQM-151A receiver, were noise limited. This condition
DoD IMT-2000 Assessment

E-33

equates to an allowed degradation in the link margins of approximately 1 dB and an I/N of -6 dB. The

assessment methodology is similar to that described previously. The required propagation loss was

determined from Equation E-3, and the required separation distance was calculated using the standard

free-space path loss equation shown in Equation E-4, rather than using ISEM, since the operational

altitude was unknown for the incumbent 1350 to 1390 MHz systems.

LP = 20Log10(Fr) + 20Log10(D) + 32.45 (E-5)

where

LP = propagation loss, in dB

Fr = receiver frequency, in MHz

D = separation distance between the transmitter antenna and the receiver antenna, in km

E.4.5.1.2 Results. The required separation distances between the incumbent 1350 to 1390 MHz

transmitters and the BQM-147A and FQM-151A receivers are contained in Table E-21 (for 10 MHz and

20 MHz of transmitter/receiver frequency separation). The required separation distances between the

BQM-147A and FQM-151A transmitters and the incumbent 1350 to 1390 MHz receivers are contained

in Table E-22 (for 10 MHz and 20 MHz of transmitter/receiver frequency separation).

Table E-21. Required Separation Distances (km) for 1350-1390 MHz Receivers

Receiver Platforms

FQM-151A BQM-147A FQM-151A BQM-147A

Frequency Off Tune Incumbent Systems 10 10 20 20

Transmitter: NGTCS BRH BRH BRH BRH

Transmitter: RAJPO BRH BRH 14.8 14.8

Transmitter: TAS MK-23 BRH BRH BRH BRH

Transmitter: AN/FPS-108 NB BRH BRH BRH BRH

Transmitter: AN/FPS-108 WB BRH BRH BRH BRH

Transmitter: AN/FPS-117 NB BRH BRH BRH BRH

Transmitter: AN/FPS-117 WB BRH BRH BRH BRH

Transmitter: AN/FPS-124 BRH BRH BRH BRH

Transmitter: AN/GRC-103 BRH BRH 91.1 91.1

Transmitter: AN/GRC-226 BRH BRH 16.6 16.6

Transmitter: AN/MRC-142 BRH BRH 16.0 16.0

Transmitter: ARSR BRH BRH BRH BRH

Transmitter: MTACS BRH BRH 216.7 216.7

Transmitter: AN/TPS-59 BRH BRH 127.7 127.7

BRH = Beyond Radio Horizon
DoD IMT-2000 Assessment

E-34

Table E-22. Required Separation Distances (km) for 1350-1390 MHz Tramsmitters

Transmitter Platforms

FQM-151A BQM-147A FQM-151A BQM-147A

Frequency Off Tune Incumbent Systems 10 10 20 20

Receiver: NGTCS 11.8 37.6 11.8 37.6

Receiver: RAJPO 6.0 9.1 0.1 0.4

Receiver: TAS MK-23 79.2 73.1 1.2 5.4

Receiver: AN/FPS-108 NB BRH BRH BRH BRH

Receiver: AN/FPS-108 WB BRH BRH BRH BRH

Receiver: AN/FPS-117 NB BRH BRH 118.3 207.9

Receiver: AN/FPS-117 WB BRH BRH 118.3 207.9

Receiver: AN/FPS-124 205.0 258.1 3.0 12.1

Receiver: AN/GRC-103 29.0 27.0 0.4 1.9

Receiver: AN/GRC-226 46.1 43.0 0.9 3.3

Receiver: AN/MRC-142 40.4 36.9 0.6 2.7

Receiver: ARSR 207.3 191.3 3.1 13.9

Receiver: MTACS 26.8 60.8 1.0 1.5

Receiver: AN/TPS-59 BRH BRH 9.7 39.2

BRH = Beyond Radio Horizon

Modifications to the BQM-147A and FQM-151A transmitters and receivers would be necessary to

migrate the systems to the 1350 to 1390 MHz band. There are several high-power radars currently

operating in this band; thus, even with 20-MHz frequency separation, some systems would require a

beyond radio horizon (BRH) separation distance, and the BQM-147A and FQM-151A would require

forward error correction (FEC) to maintain a marginal communications link.

E.4.5.2 Migrating to the 2200-2290 MHz Frequency Band

The systems located within the EME are listed in Table E-23. The analyzed 2200 to 2290 MHz systems

are identified below. Table E-24 lists the transmitter characteristics of the 2200 to 2290 MHz systems,

and Table E-25 lists the receiver characteristics of the 2200 to 2290 MHz systems.

In addition to the incumbent 2200 to 2290 MHz systems listed in Table E-25, the National Aeronautics

and Space Administration (NASA) maintains a Deep Space Network (DSN) at Goldstone, CA, near Fort

Irwin, CA. The DSN 2200 to 2290 MHz receiver front-ends have very low noise characteristics

(-192 dB/Hz) and use a 32-dBi parabolic dish antenna to track spacecraft from horizon to 90o

 zenith.
DoD IMT-2000 Assessment

E-35

Table E-23. Systems Located Within the EME

Nomenclature Number of

Systems

Nomenclature Number of

Systems

Nomenclature Number of

Systems

AAC AR3605S 1 CXS 610 XPNDR 2 MOT TDRSS XPNDR 1

AN/DKT-023 (V) 4 DRA DESIGN 2 NASA DESIGN 4

AN/DKT-031 (V) 4 EOS AM/TDRSS 4 NASA DSN DESIGN 2

AN/DKT-038 1 ESA DESIGN 5 NASA NEAR EARTH TR 9

AN/DKT23 6 FASDSN TELEMETRY 3 NASA SMEX XPNDR 4

AN/DKT-23 1 FECLR42000 6 NASA XPNDR 12

AN/DKT30 2 GENTRANSPONDER 4 NASA/ESA DESIGN 1

AN/DKT-30 1 GERMAN SATELLITE 2 PHI GOES 3

AN/DKT-31 60 GRA60183A/24 2 PHI GOES XPNDR 1

AN/DKT-31(V) 4 HUGT802 16 RAYRTT-601 2

AN/DKT37 2 ISAS DESIGN 1 RCA TRANSMITTER 1

AN/DKT-37 16 L3 COMM CSX-600B 8 RCAMULTIBNDTRNSL 1

AN/DKT37D 19 LOCCTS905 1 RIETRANSPONDER 12

AN/DKT-49 4 LOCCTS-905 3 SEOTTS1A 3

AN/DKT-56 10 LOE CTS-905 1 SMWTTX135-5A 4

AN/DKT-73 18 LOE CXS-600A STDN 1 SOVXM-LTA 4

AN/DKT-80 91 LOE LORAL CONIC 1 SPACE INNOVATIONS 2

AN/DNQ1 1 LOECONIC LC-CTS-10 2 ST-402-S 3

APIT1478D 8 LOECTS515C5 2 STD NEAR EARTH XPN 4

API-T1478D 4 LOECTS905 9 STDN XPNDR 7

AYD ST408S 1 LOECTS-905 1 TDC1098V 3

AYDST402S 12 MCCM903 1 TDE/TAP TRANSMITTE 1

AYDST408S 2 MCCT1025S 1 TELTR2202 3

AYDST409 4 MCCT4X-2 1 TERTCM601 3

AYDT105 12 MCCT4X-S 4 TRW TRANSPONDER 14

AYDT105S 3 MCCT-60 1 TRW XPNDR 1

AYDT400 1 MCCT70 2 TRWTLMTX 1

AYDVECTORT-805S 1 MCCT702 1 TRWTRANSPONDER 2

CANADIAN DESIGN 2 MCCT705 2 TRWTWIDEBAND 1

CEL TLM XMTR 1 MCCT705HR 12 TSC TR2400 3

CIN MODEL TTC 701 1 MCCT705S 4 TSCTR 2202 3

CNC L-3 COMM 1 MCCT802 10 TTSDR2D 1

CNCAIM9X ATE 7 MCCTV1205 1 VEC105S 1

CNCCTMUHF302 9 MCOT702 1 VECST405S 3

CNCCTMUHF310 1 MCT TDRSS NE 3 VECT-1025 11

CNCCTMUHF401 1 MDC1400MR 3 VECT-102S 13

CNCCTS402 24 MICROCOMT70 1 VECT1055 11

CNCCTS705 13 MODEL CXS-600 STDN 3 VECT105S 11

CNCCTS905 4 MOT 2ND 1 VECT-105S 4

CNCSA2747-1 2 MOT MODEL USB 1 VECT110S 5

CONIC CXS-600B 2 MOT STDN XPNDR 2 VECT1O2S 2

CUB TR-38 1 MOT TDRSS TRNSPDR 7 VECT402L 2
DoD IMT-2000 Assessment

E-36

Table E-24. 2200-2290 MHz Systems Transmitter Characteristics

Transmitter Characteristics Antenna

Characteristics

Emission Bandwidth (MHz) Platform Power (W) Modulation Type -3 dB -20 dB -40 dB -60 dB Gain (dBi)

AN/DKT-xx 2 FSK 0.100 0.200 0.400 0.980 5

AN/DKT-37D(v) 2 FM 0.250 0.600 N/A 1.2 0

AN/DKT-31(v) 5 PAM NRZ 0.600 1.28 N/A 1.6 2

Loral CXS-800 5 BPSK NRZ-L 3.8 6.9 11.2 17 0

RF1

0.400 1.9 N/A 3.7 5

RF2 AN/DKT-27 (MOD) 5 N/A

0.200 1 N/A 2.5 0

AN/DKT-56 2 FM 0.100 0.200 0.400 0.980

AN/DKT-23 2-5 PAM FM 1.6 4.8 N/A 9.6 5

PROG 777 1 PCM PM 2 5 N/A 8 5.3

DMSP 3.7 PM weather data 2 13.5 37 38.7 1

DMSP 3.7 PM weather data 0.157 0.480 N/A 5.6 1

DMSP 2 PM telemetry 0.930 6.8 9.8 12.4 4

Aydin Vector T/ST 400 20 FM 5.8 5.9 N/A 13 0

NRZ – Non-Return-to Zero (modulation)

NRZ – Non-Return-to-Zero-Level

Table E-25. 2200-2290 MHz Systems Receiver Characteristics

Receiver Characteristics

RF Bandwidth (MHz) 1st IF Receiver

Selectivity (MHz)

2nd IF Receiver

Platform Selectivity (MHz)

Noise

Figure

(dB) -3 dB -20 dB -60 dB -3 dB -20 dB -60 dB -3 dB -20 dB -60 dB

Antenna

Gain

(dBi)

AN/DKT-xx 10 6 N/A N/A 4 6.1 12 1 1.5 3 20.9

AN/DKT-37D(v) 10 6 N/A N/A 4 6.1 12 1 1.5 3 20.9

AN/DKT-31(v) 10 6 N/A N/A 4 6.1 12 1 1.5 3 20.9

Loral CXS-800 10 6 N/A N/A 4 6.1 12 1 1.5 3 20.9

AN/DKT-27

Modified (MOD) 10 6 N/A N/A 4 6.1 12 1 1.5 3 20.9

AN/DKT-56 10 6 N/A N/A 4 6.1 12 1 1.5 3 20.9

AN/DKT-23 10 6 N/A N/A 4 6.1 12 1 1.5 3 20.9

PROG 777 10 6 N/A N/A 4 6.1 12 1 1.5 3 20.9

DMSP 8 100 N/A N/A 10 12 100 N/A N/A 3 20.9

DMSP 8 20 50 100 2 5 10 0.200 0.500 3 20.9

DMSP 8 22 50 130 17 23 29 4 7.9 3 20.9

Aydin Vector

T/ST 400 10 225 350 500 45 86 292 20 24 3 20.9
DoD IMT-2000 Assessment

E-37

E.4.5.2.1 Technical Assessment. To analyze interference from the BQM-147A and FQM-151A

transmitters into incumbent 2200 to 2290 MHz receivers, and interference from the incumbent 2200 to

2290 MHz transmitters into the BQM-147A and FQM-151A receivers, the required separation distances

to preclude interference were calculated. It was assumed that the incumbent 2200 to 2290 MHz

receivers, the BQM-147A receiver and the FQM-151A receiver, were noise limited. This condition

equates to an allowed degradation in the link margins of approximately 1 dB and an I/N of -6 dB. The

assessment methodology is similar to that described previously. The required propagation loss was

determined from Equation E-3, and the required separation distance was calculated using Equation E-4,

rather than using ISEM, since the operational altitude was unknown for the incumbent 2200 to 2290

MHz systems.

E.4.5.2.2 Results. The required separation distances between the incumbent 2200 to 2290 MHz

transmitters and the BQM-147A, FQM-151A receivers are contained in Table E-26 (for 10 MHz and 20

MHz of transmitter/receiver frequency separation). The required separation distances between the

BQM-147A and FQM-151A transmitters and the incumbent 2200 to 2290 MHz receivers are contained

in Table E-27 (for 10 MHz and 20 MHz of transmitter/receiver frequency separation).

In addition to the incumbent systems, the minimum separation distances were calculated using Equation

E-2 and Equation E-4 for interference from the UAV to the DSN receivers. Results are provided in

Table E-27.
DoD IMT-2000 Assessment

E-38

Table E-26. Distances, in km, from Incumbent 2200-2290 MHz Airborne Transmitters to

Preclude Interference to BQM-147A and FQM-151A Ground Receivers

Receiver Platforms

BQM-147A FQM-151A BQM-147A FQM-151A

Incumbent Systems Frequency Off Tune

10 MHz 10 MHz 20 MHz 20 MHz

Transmitter: AN/DKT-xx BRH BRH 1.7 1.7

Transmitter: AN/DKT-37D (v) 167 167 0.8 0.8

Transmitter: AN/DKT-31 (v) BRH BRH 1.3 1.3

Transmitter: PROG 777

Transmitter: AN/DKT-27 (MOD) BRH BRH 0.5 0.5

Transmitter: AN/DKT-56 168 168 0.9 0.9

Transmitter: AN/DKT-23 BRH BRH 2.3 2.3

Transmitter: PROG 777 227 227 1.1 1.1

Transmitter: DMSP 263 263 6.9 6.9

Transmitter: DMSP 254 254 3.9 3.9

Transmitter: DMSP 270 270 1.5 1.5

Transmitter: Aydin Vector T/ST 400 BRH BRH 2.9 2.9

BRH = Beyond Radio Horizon

Table E-27. Distances, in km, from BQM-147A and FQM-151A Airborne Transmitters to

Preclude Interference to Incumbent 2200-2290 Receivers

Transmitter Platform

BQM-147A FQM-151A BQM-147A FQM-151A

Incumbent Systems Frequency Off Tune

10 MHz 10 MHz 20 MHz 20 MHz

Receiver: AN/DKT-xx 23.2 23.5 1.6 0.3

Receiver: AN/DKT-37D (v) 23.2 23.5 1.6 0.3

Receiver: AN/DKT-31 (v) 23.2 23.5 1.6 0.3

Receiver: AN/DKT-27 (MOD) 19.3 19.6 1.3 0.3

Receiver: AN/DKT-56 23.2 23.2 1.6 0.3

Receiver: AN/DKT-23 23.2 23.2 1.6 0.3

Receiver: DMSP BRH BRH BRH BRH

Receiver: DMSP 18.4 18.9 1.35 0.3

Receiver: DMSP 166 288 9.6 2.5

Receiver: Aydin Vector T/ST 400 2 2 0.2 0.02

Receiver: DSN BRH* BRH*

BRH = Beyond Radio Horizon

* - On Tune, FDR was 0 dB
DoD IMT-2000 Assessment

E-39

By maintaining at least 10-MHz frequency separation, the BQM-147A and FQM-151A can operate

within a reasonable separation distance from the incumbent 2200 to 2290 MHz systems. To migrate to

the 2200 to 2290 MHz frequency band and maintain a link margin, the BQM-147A and FQM-151A

must increase either the transmitter antenna gain, transmitter power, or receiver antenna gain by 1.9 dB.

Failure to maintain this link margin could result in up to a 24% reduction in communication range.

E.4.5.3 Migrating to the 4400-4940 MHz Frequency Band

The systems located within the EME are listed in Table E-28. The analyzed 4400 to 4940 MHz systems

are identified below.

Table E-29 lists the transmitter characteristics of the 4400 to 4490 MHz systems, and Table E-30 lists

the receiver characteristics of the 4400 to 4940 MHz systems.

E.4.5.3.1 Technical Assessment. To analyze interference from the BQM-147A and FQM-151A

transmitters into incumbent 4400 to 4940 MHz receivers, and interference from the incumbent 4400 to

4940 MHz transmitters into the BQM-147A and FQM-151A receivers, the required separation distances

to preclude interference were calculated. It was assumed that the incumbent 4400 to 4940 MHz

receivers, the BQM-147A receiver and the FQM-151A receiver, were noise limited. This condition

equates to an allowed degradation in the link margins of approximately 1 dB and an I/N of -6 dB. The

analysis methodology is similar to that described previously. The required propagation loss was

determined from Equation E-3, and the required separation distance was calculated using Equation E-4,

rather than using ISEM, since the operational altitude was unknown for the incumbent 4400 to 4940

MHz systems.

E.4.5.3.2 Results. The required separation distances between the incumbent 4400 to 4940 MHz

transmitters and the BQM-147A and FQM-151A receivers are contained in Table E-31 (for 10 MHz and

20 MHz of transmitter/receiver frequency separation). The required separation distances between the

BQM-147A and FQM-151A transmitters and the incumbent 4400 to 4940 MHz receivers are contained

in Table E-32 (for 10 MHz and 20 MHz of transmitter/receiver frequency separation).
DoD IMT-2000 Assessment

E-40

Table E-28. 4400-4940 MHz Systems Located Within the EME

Nomenclature Number of

Systems

Nomenclature Number of

Systems

Nomenclature Number of

Systems

AAC AR3605S 1 CUB TR-38 TRANSPON 1 MOT TDRSS XPNDR 1

AN/DKT-023 (V) 4 CXS 610 XPNDR 2 NASA DESIGN 4

AN/DKT-031 (V) 4 DRA DESIGN 2 NASA DSN DESIGN 2

AN/DKT-038 1 EOS AM/TDRSS 4 NASA NEAR EARTH TR 9

AN/DKT23 6 ESA DESIGN 5 NASA SMEX XPNDR 4

AN/DKT-23 1 FASDSN TELEMETRY 3 NASA XPNDR 12

AN/DKT30 2 FECLR42000 6 NASA/ESA DESIGN 1

AN/DKT-30 1 GENTRANSPONDER 4 PHI GOES 3

AN/DKT-31 60 GERMAN SATELLITE 2 PHI GOES XPNDR 1

AN/DKT-31(V) 4 GRA60183A/24 2 RAYRTT-601 2

AN/DKT37 2 HUGT802 16 RCA TRANSMITTER 1

AN/DKT-37 16 ISAS DESIGN 1 RCAMULTIBNDTRNSL 1

AN/DKT37D 19 L3 COMM CSX-600B 8 RIETRANSPONDER 12

AN/DKT-49 4 LOCCTS905 1 SEOTTS1A 3

AN/DKT-56 10 LOCCTS-905 3 SMWTTX135-5A 4

AN/DKT-73 18 LOE CTS-905 1 SOVXM-LTA 4

AN/DKT-80 91 LOE CXS-600A STDN 1 SPACE INNOVATIONS 2

AN/DNQ1 1 LOE LORAL CONIC 1 ST-402-S 3

APIT1478D 8 LOECONIC LC-CTS-10 2 STD NEAR EARTH XPN 4

AN/GRC-222 1 LOECTS515C5 2 STDN XPNDR 7

AN/TRC-170 1 LOECTS905 9 TDC1098V 3

API-T1478D 4 LOECTS-905 1 TDE/TAP TRANSMITTE 1

AYD ST408S 1 MCCM903 1 TELTR2202 3

AYDST402S 12 MCCT1025S 1 TERTCM601 3

AYDST408S 2 MCCT4X-2 1 TRW TRANSPONDER 14

AYDST409 4 MCCT4X-S 4 TRW XPNDR 1

AYDT105 12 MCCT-60 1 TRWTLMTX 1

AYDT105S 3 MCCT70 2 TRWTRANSPONDER 2

AYDT400 1 MCCT702 1 TRWTWIDEBAND 1

AYDVECTORT-805S 1 MCCT705 2 TSC TR2400 3

CANADIAN DESIGN 2 MCCT705HR 12 TSCTR 2202 3

CEL TLM XMTR 1 MCCT705S 4 TTSDR2D 1

CIN MODEL TTC 701 1 MCCT802 10 VEC105S 1

CNC L-3 COMM 1 MCCTV1205 1 VECST405S 3

CNCAIM9X ATE 7 MCOT702 1 VECT-1025 11

CNCCTMUHF302 9 MCT TDRSS NE 3 VECT-102S 13

CNCCTMUHF310 1 MDC1400MR 3 VECT1055 11

CNCCTMUHF401 1 MICROCOMT70 1 VECT105S 11

CNCCTS402 24 MODEL CXS-600 STDN 3 VECT-105S 4

CNCCTS705 13 MOT 2ND 1 VECT110S 5

CNCCTS905 4 MOT MODEL USB 1 VECT1O2S 2

CNCSA2747-1 2 MOT STDN XPNDR 2 VECT402L 2

CONIC CXS-600B 2 MOT TDRSS TRNSPDR 7
DoD IMT-2000 Assessment

E-41

Table E-29. 4400-4940 MHz Systems Transmitter Characteristics

Transmitter Characteristics Antenna

Characteristics

Emission Bandwidth (MHz) Platform Power (W) Modulation

Type -3 dB -20 dB -40 dB -60 dB Gain (dBi)

AN/TRC-97 1000 FM 0.780 1 N/A 1.5 9

AN/TRC-97 1000 FM 0.966 1.5 N/A 2 38

Pioneer SR RPV 30 (TCU)

10 (PCS) SS PSK 12.5 32.5 37 60 30

Pioneer SR RPV 30 FM 2 13.5 25.3 38.7 30

TUAV BMS D/V Link 3 FM 0.0745 0.1008 0.242 0.7366 29

TUAV BMS D/V Link 10 FM 3 15 23 29 5.5

Pioneer SR Remotely Piloted

Vechicle (RPV) (MOD)

2000 (ship,land)

4000 (air) FM SS 11 17.7 36.9 73.8 21

Pioneer SR RPV (MOD) 2000 (ship,land)

4000 (air) FM SS 11 17.7 36.9 73.8 21

PCS – Portable Communications System

SS – Spread Spectrum

TCU – Tracking and Communications Unit

Table E-30. 4400-4940 MHz Systems Receiver Characteristics

Receiver Characteristics

RF Bandwidth (MHz) 1st IF Receiver

Selectivity (MHz)

2nd IF Receiver

Platform Selectivity (MHz)

Noise

Figure

(dB) -3 dB -20 dB -60 dB -3 dB -20 dB -60 dB -3 dB -20 dB -60 dB

Antenna

Gain

(dBi)

AN/TRC-97 7 20 40 120 1.5 2.8 8 0.220 1.2 N/A 38

AN/TRC-97 7 20 40 120 1.5 2.8 8 0.220 1.2 N/A 38

Pioneer SR RPV 7 180 205 280 30 45 100 1.2 4.5 10 34

Pioneer SR RPV 7 66 100 190 32 60 280 22 40 84 10

2nd

7 8 25

3rd

TUAV BMS D/V

Link 2 225 350 500 45 86 292

20 24 30

5.5

TUAV BMS D/V

Link 3.5 225 350 500 45 86 292 20 24 30 29

1st 2nd

810 950 1680 15.3 21 50

2nd 3rd

Pioneer SR RPV

(MOD) 8

30 42.5 70

25 50 150

2.2 3 7

20

1st

810 950 1680

2nd

Pioneer SR RPV

(MOD) 6

30 42.5 70

25 50 150 0.728 1.2 1.6 3.7
DoD IMT-2000 Assessment

E-42

Table E-31. Distances, in km, from Incumbent 4400-5000 MHz Airborne Transmitters to

Preclude Interference to BQM-147A and FQM-151A Receivers

Receiver Platform

BQM-147A FQM-151A BQM-147A FQM-151A

Incumbent Systems Frequency Off Tune

10 MHz 10 MHz 20 MHz 20 MHz

Transmitter: AN/TRC-97 BRH BRH BRH BRH

Transmitter: AN/TRC-97 BRH BRH BRH BRH

Transmitter: Pioneer SR RPV BRH BRH BRH BRH

Transmitter: TUAV BMS D/V Link 263.4 263.4 6.9 6.9

Transmitter: TUAV BMS D/V Link 254.5 254.5 3.9 3.9

Transmitter: Pioneer SR RPV (MOD) 270.4 270.4 1.5 1.5

Transmitter: Pioneer SR RPV (MOD) BRH BRH 29.5 29.5

BRH = Beyond Radio Horizon

Table E-32. Distances, in km, from BQM-147A and FQM-151A Airborne Transmitters to

Preclude Interference to Incumbent 4400-5000 Receivers

Transmitter Platforms

BQM-147A FQM-151A BQM-147A FQM-151A

Incumbent Systems Frequency Off Tune

10 MHz 10 MHz 20 MHz 20 MHz

Transmitter: AN/TRC-97 134.6 213.4 9.9 2.8

Transmitter: AN/TRC-97 134.6 137.8 9.9 2.1

Transmitter: Pioneer SR RPV 104.4 93.1 6.6 1.6

Transmitter: TUAV BMS D/V Link BRH BRH BRH BRH

Transmitter: TUAV BMS D/V Link 18.4 18.9 1.4 0.3

Transmitter: Pioneer SR RPV (MOD) 288.6 166.1 9.6 2.5

Transmitter: Pioneer SR RPV (MOD) 4.6 4.7 0.3 0.1

BRH = Beyond Radio Horizon

Maintaining a link margin and migrating to the 4400 to 4940 MHz frequency band would require a

8.1 dB increase of transmitter antenna gain, transmitter power, or receiver antenna gain. If

modifications are not completed, the communication range could be reduced up to 61%. This

requirement may be prohibitive without extensive modifications. At this frequency band the increased

transmitter power and very directional antennas with tracking systems cost more and may be weight

prohibitive. Since the beam width of an antenna is proportional to the gain, a higher gain antenna will

have a narrower beam width, which may not be feasible for some systems.
DoD IMT-2000 Assessment

E-43

This option is not attractive to the Army since a new band would have to be found and a determination

made to the availability of appropriate transmitter modules of the size and weight needed for the Pointer

UAV. Overall operational impact is minimal since only four models have been fielded, so far.

However, a change will require a delay in the continued fielding, delaying use by Army infantry units,

Air Force security forces, and NASA launch facilities monitoring.

E.5 US ARMY ABERDEEN TEST CENTER

E.5.1 Operational Mission

The ATC Range Telemetry System provides a multi-link radio telemetry communication capability

throughout the many test ranges and facilities of the Aberdeen Test Center (ATC). It consists of several

fixed receiving stations located at the high-usage ranges/test areas and many transportable (vehicle

housed) receiving stations which are emplaced at any of the multitude of ATC test areas or remote test

sites when required to support testing projects. Transmitters are installed on the items being tested on

the ranges and communicate the various data (video, high-rate vetronics, analog, digital) to the receiving

station. The test mission and workload of the ATC requires daily support by the telemetry system; it is

vital to the accomplishment of the test and evaluation of military equipment, primarily combat and

tactical vehicles, and many items of support equipment. Testing under dynamic conditions is a

requirement, and the telemetry system provides the capability to transfer engineering measurements

from the moving vehicle to a data collection center.

E.5.2 OPTION 1 – FULL BAND SHARING

This is not a workable solution. Telemetry transmits continuously during the work day. Interference

from IMT-2000 users operating at the same frequencies would disrupt the acquisition of data in support

of the testing of military vehicles and equipment, essentially shutting down the test range. This inhibits

the development and testing on new combat applications for combat units.

E.5.3 OPTION 2 – BAND SEGMENTATION/PARTIAL BAND SHARING

This band contains approximately 50% of the assets of the ATC range telemetry. Inside this band a

portion of the equipment cannot be modified to operate in the band segment and must be replaced; other

equipment can be adapted or tuned and made usable. Additional frequencies must be made available

and selected to eliminate interference with the current frequencies.
DoD IMT-2000 Assessment

E-44

E.5.4 OPTION 3 – PARTIAL BAND SEGMENTATION/OTHER BAND

COMBINATION (IF VIABLE)

See Option 2.

E.5.5 OPTION 4 – VACATE 1755-1850 MHZ

Unless additional spectrum is allocated and new equipment is procured and fielded, range operations

will be affected adversely. Also, the propagation characteristics of any new band for relocation needs to

carefully studied. The current band allows the use of wide beam width antennas, helical antennas

resistant to wind and water movement, use of non-expensive radar-slaved antennas for tracking aircraft,

and foliage penetration.

E.6 TCM-601

E.6.1 OPERATIONAL MISSION

The TCM-601 (TOSS) provides a television ordinance scoring capability to range users in support of

exercise and test missions at Nellis Range. For the year 2001, sixteen one-week sessions will occur for

Red Flag exercises alone. The average number of missions using TOSS at Nellis Range exceeds 50,000

per year for both US and Allied forces. TOSS is a field-proven, accurate weapons scoring system with a

night scoring system using infrared cameras. Scoring can be done for live or inert conventional

weapons. The operational employment of TOSS provides scoring for over 21 targets with over 100 aim

points. There is no planned replacement for this system.

E.6.2 OPTION 1 – FULL BAND SHARING

Since the TOSS system can not share with IMT-2000, the system would be rendered non-operational.

Without the feedback from TOSS, range scoring would revert to manual methods. This inability to

produce near-instantaneous feedback negatively affects the quality of crew training. Training missions

involving multiple bombing runs would not have the benefit of feedback from previous ordnance drops

to correct any deficiencies before the next drop.
DoD IMT-2000 Assessment

E-45

E.6.3 OPTION 4 – VACATE 1755-1850 MHZ

TOSS has no planned replacement system. Until a replacement system is developed and fielded, TOSS

must remain operational to ensure quality training is maintained. The only workaround is manual range

scoring which reverts aircrew training back to 1950s technology.

E.7 COST ISSUES FOR OTHER SYSTEMS

E.7.1 Army Corps of Engineers

The primary DoD user of point-to-point microwave links in the band is the ACE. They have over 300

links, mostly in very isolated regions, throughout the US. Under either the band segmentation option or

the band vacation option these links would be relocated to 6 GHz, requiring more towers and replacing

virtually of the equipment. Refer to Table E-33 for reimbursement cost data.

Table E-33. Army Corps of Engineers Point-to-Point Microwave Links (TY$M)

Service FY02 FY03 FY04 FY05 FY06 FY07 To Complete Total

Reimbursement Cost Army 0.0 0.0 0.0 0.0 0.0 0.0 125.0 125.0

E.7.2 Land Warrior/CIDDS

The Land Warrior and CIDDS Army programs are still in the development phase. The modification to

either program would be much more extensive if the entire band was lost versus the band segmentation

options. Since both systems are planning to begin production in the FY02-03 period, delaying their

modification will only cause a much larger fraction of the equipment being procured to require

retrofitting—a much more expensive process than initiating the modification prior to the production

start. For this reason, the cost for delaying the modification of these systems to be more coincident with

either a 2006 or 2010 introduction of IMT-2000 systems is not included in Table E-34. Instead, only the

most economical, (i.e., earliest possible modification), plan is presented for the band segmentation and

total band loss options for these systems.

Table E-34. Land Warrior and CIDDS Systems (TY$M)

Service FY02 FY03 FY04 FY05 FY06 FY07 To Complete Total

Land Warrior (Band Segmentation Options) Army 1.1 0.0 0.0 0.0 0.0 0.0 0.0 1.1

Land Warrior (Band Vacation Options) Army 5.3 0.0 0.0 0.0 0.0 0.0 0.0 5.3

CIDDS (Band Segmentation Options) Army 1.1 2.0 0.7 0.0 0.0 0.0 0.0 3.8

CIDDS (Band Vacation Options) Army 32.4 16.7 1.8 0.2 0.2 0.2 7.0 58.5
DoD IMT-2000 Assessment

E-46

E.7.3 Miscellaneous Systems

Many small systems also utilize the 1755-1850 MHz band, from perimeter security systems to scoring

systems for combat training. Each of these will require modification to some extent in either the band

segmentation or band vacation options. Because by and large these systems utilize non-developmental

commercial equipment they typically require replacement regardless of the loss of some or all of the

band. They, of course, would not have any significant cost associated with the band sharing option.

Table E-35 represents the costs to replace these systems under both the segmentation and total band loss

options. The various fixed point-to-point microwave links mentioned in the table do not include any of

the links associated with the Army Corps of Engineers, ACTS ranges, TOSS, MSE, or TRI-TAC

systems that have been addressed previously. Of course, for the various introduction dates some or all

of these replacement costs could be deferred but typically at higher cost. Therefore, for economic

reasons immediate replacement was assumed regardless of the IMT-2000 introduction date.

Table E-35. Miscellaneous Equipment Cost Data (TY$M)

Service FY02 FY03 FY04 FY05 FY06 FY07 To Complete Total

Tayburn Video Data Link Army 0.4 0.0 0.0 0.0 0.0 0.0 0.0 0.4

AN/DSQ-024A/B Scoring System Army 1.8 0.0 0.0 0.0 0.0 0.0 0.0 1.8

AN/DSQ-040 Miss Distance Indicator Army 0.5 0.0 0.0 0.0 0.0 0.0 0.0 0.5

Thru Sight Video (TSV) System Army 1.5 0.0 0.0 0.0 0.0 0.0 0.0 1.5

GTE Lenkurt 79F1 Microwave Radio Army 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.1

Simplex Microwave Data Link Army 0.2 0.0 0.0 0.0 0.0 0.0 0.0 0.2

Conic CTM-UHF-402V Video Transmitter Army 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

AN/DSQ(XMG-1) Missile Scoring Set Army 0.4 0.0 0.0 0.0 0.0 0.0 0.0 0.4

Security Video Systems AF 0.3 0.0 0.0 0.0 0.0 0.0 0.0 0.3

Security Video Systems Navy 0.3 0.0 0.0 0.0 0.0 0.0 0.0 0.3

ATC Range Telemetry System Army 2.1 1.0 0.0 0.0 0.0 0.0 0.0 3.1

Dynamically Reconfigured Real Time Software Army 7.7 0.0 0.0 0.0 0.0 0.0 0.0 7.7

Various Fixed Mircrowave Links All 45.0 0.0 0.0 0.0 0.0 0.0 0.0 45.0

Total Reimbursement 60.3 1.0 0.0 0.0 0.0 0.0 0.0 61.3
DoD IMT-2000 Assessment

F-1/F-2

APPENDIX F – MOBILE VIDEO/CONTROL LINKS

(This classified appendix is bound separately.)
DoD IMT-2000 Assessment

G-1

APPENDIX G – DISCUSSION OF MITIGATION METHODS

Individual system design considerations, environmental site planning, cooperative frequency planning,

and other cooperative measures can often mitigate the potential for harmful interference between radio

frequency systems. The implementation of interference mitigation measures can greatly enhance

opportunities for spectrum sharing. The assessments contained in Appendices B through E and the

classified supplement include suggested means to mitigate possible harmful interference, if undesired

interactions were predicted. A complete exploration and quantification of the technical, cost, and

operational impact of the indicated mitigation measures was not possible given the uncertainty of some

International Mobile Telecommunications for the Year 2000 (IMT-2000) technical parameters and

schedule limitations on this assessment. The operational risks associated with possible mitigation

measures are either addressed in the appendices and results or require further investigation. Many of the

techniques were found not to be practical or operationally acceptable. It is important to note that costs

for these mitigation techniques have not been calculated. Employing any of these techniques would

require a cost assessment and may dramatically alter the cost estimates presented earlier.

• In selected areas, implement an IMT-2000 network design that eliminates base station mainbeam

illumination of Department of Defense (DoD) operational areas.

• In selected areas, implement an IMT-2000 network design using minimally acceptable

transmitter power levels.

• In selected areas, investigate possible IMT-2000 base station antenna nulling.

• Relocate the satellite operations (SATOPS) uplink antennas and/or SATOPS transmission offloading.

• Implement SATOPS antenna elevation angle restrictions.

• Reduce the out-of-beam energy of the SATOPS antennas.

• Investigate SATOPS signal blockage, use of radio frequency absorptive material, and antenna

redesign.

• Investigate SATOPS power management.

• Identify keep-out zones for IMT-2000 mobile units around designated DoD sites.

• Consider polarization discrimination between SATOPS antennas and IMT-2000 base station

antennas.

• Implement cooperative scheduling of SATOPS transmissions with IMT-2000 network operations

centers, allowing real-time frequency management.

• Investigate segmenting the 1755-1850 MHz frequency band; however, segmentation of the 1755-

1850 MHz band may result in spectrum spillover into adjacent bands.
DoD IMT-2000 Assessment

G-2

• Investigate cross-polarization between IMT-2000 base stations and tactical radio relay to reduce

the level of interference interactions.

• Investigate the possibility of using less conservative interference thresholds by insuring that

neither IMT-2000 systems nor DoD systems operate near minimally acceptable signal levels.

• Coordinate antenna orientation of IMT-2000 base stations with the location of the test ranges.

The mainbeams of the IMT-2000 antennas should not point in the direction of training range

ground stations or of major flight activity, and the IMT-2000 base stations should not be

illuminated by the mainbeams of high-gain Air Combat Training Systems (ACTS) ground station

antennas.

• Use polarization diversity between IMT-2000 base stations and ACTS equipment, to reduce

interference levels for mainbeam-to-mainbeam interactions between IMT-2000 and ACTS

equipment.
DoD IMT-2000 Assessment

ATTACHMENT 1
1

Topography Around CTS, Colorado Springs, Colorado
2

CTS, Antenna Elevation Angle: 3°, Transmitter Power: 100 W, IMT-2000 Base Station

CTS, Antenna Elevation Angle: 3°, Transmitter Power: 2,250 W, IMT-2000 Base Station
3

CTS, Antenna Elevation Angle: 5°, Transmitter Power: 100 W, IMT-2000 Base Station

CTS, Antenna Elevation Angle: 5°, Transmitter Power: 2,250 W, IMT-2000 Base Station
4

CTS, Antenna Elevation Angle: 10°, Transmitter Power: 100 W, IMT-2000 Base Station

CTS, Antenna Elevation Angle: 10°, Transmitter Power: 2,250 W, IMT-2000 Base Station
5

CTS, Antenna Elevation Angle: 3°, Transmitter Power: 100 W, IMT-2000 Mobile Station

CTS, Antenna Elevation Angle: 3°, Transmitter Power: 2,250 W, IMT-2000 Mobile Station
6

CTS, Antenna Elevation Angle: 5°, Transmitter Power: 100 W, IMT-2000 Mobile Station

CTS, Antenna Elevation Angle: 5°, Transmitter Power: 2,250 W, IMT-2000 Mobile Station
7

CTS, Antenna Elevation Angle: 10°, Transmitter Power: 100 W, IMT-2000 Mobile Station

CTS, Antenna Elevation Angle: 10°, Transmitter Power: 2,250 W, IMT-2000 Mobile Station
8

Topography Around NHS, Manchester, New Hampshire
9

NHS-DLT, Antenna Elevation Angle: 3°, Transmitter Power: 100 W, IMT-2000 Base Station

NHS-B, Antenna Elevation Angle: 3°, Transmitter Power: 100 W, IMT-2000 Base Station
10

NHS-A, Antenna Elevation Angle: 3°, Transmitter Power: 100 W, IMT-2000 Base Station

NHS-DLT, Antenna Elevation Angle: 3°, Transmitter Power: 1,000 W, IMT-2000 Base Station
11

NHS-B, Antenna Elevation Angle: 3°, Transmitter Power: 2,500 W, IMT-2000 Base Station

NHS-A, Antenna Elevation Angle: 3°, Transmitter Power: 10,0000 W, IMT-2000 Base Station
12

NHS-DLT, Antenna Elevation Angle: 5°, Transmitter Power: 100 W, IMT-2000 Base Station

NHS-B, Antenna Elevation Angle: 5°, Transmitter Power: 100 W, IMT-2000 Base Station
13

NHS-A, Antenna Elevation Angle: 5°, Transmitter Power: 100 W, IMT-2000 Base Station

NHS-DLT, Antenna Elevation Angle: 5°, Transmitter Power: 1,000 W, IMT-2000 Base Station
14

NHS-B, Antenna Elevation Angle: 5°, Transmitter Power: 2,500 W, IMT-2000 Base Station

NHS-A, Antenna Elevation Angle: 5°, Transmitter Power: 10,000 W, IMT-2000 Base Station
15

NHS-DLT, Antenna Elevation Angle: 10°, Transmitter Power: 100 W, IMT-2000 Base Station

NHS-B, Antenna Elevation Angle: 10°, Transmitter Power: 100 W, IMT-2000 Base Station
16

NHS-A, Antenna Elevation Angle: 10°, Transmitter Power: 100 W, IMT-2000 Base Station

NHS-DLT, Antenna Elevation Angle: 10°, Transmitter Power: 1,000 W, IMT-2000 Base Station
17

NHS-B, Antenna Elevation Angle: 10°, Transmitter Power: 2,500 W, IMT-2000 Base Station

NHS-A, Antenna Elevation Angle: 10°, Transmitter Power: 10,000 W, IMT-2000 Base Station
18

NHS-DLT, Antenna Elevation Angle: 3°, Transmitter Power: 100 W, IMT-2000 Mobile Station

NHS-B, Antenna Elevation Angle: 3°, Transmitter Power: 100 W, IMT-2000 Mobile Station
19

NHS-A, Antenna Elevation Angle: 3°, Transmitter Power: 100 W, IMT-2000 Mobile Station

NHS-DLT, Antenna Elevation Angle: 3°, Transmitter Power: 1,000 W, IMT-2000 Mobile Station
20

NHS-B, Antenna Elevation Angle: 3°, Transmitter Power: 2,500 W, IMT-2000 Mobile Station

NHS-A, Antenna Elevation Angle: 3°, Transmitter Power: 10,000 W, IMT-2000 Mobile Station
21

NHS-DLT, Antenna Elevation Angle: 5°, Transmitter Power: 100 W, IMT-2000 Mobile Station

NHS-B, Antenna Elevation Angle: 5°, Transmitter Power: 100 W, IMT-2000 Mobile Station
22

NHS-A, Antenna Elevation Angle: 5°, Transmitter Power: 100 W, IMT-2000 Mobile Station

NHS-DLT, Antenna Elevation Angle: 5°, Transmitter Power: 1,000 W, IMT-2000 Mobile Station
23

NHS-B, Antenna Elevation Angle: 5°, Transmitter Power: 2,500 W, IMT-2000 Mobile Station

NHS-A, Antenna Elevation Angle: 5°, Transmitter Power: 10,000 W, IMT-2000 Mobile Station
24

NHS-DLT, Antenna Elevation Angle: 10°, Transmitter Power: 100 W, IMT-2000 Mobile Station

NHS-B, Antenna Elevation Angle: 10°, Transmitter Power: 100 W, IMT-2000 Mobile Station
25

NHS-A, Antenna Elevation Angle: 10°, Transmitter Power: 100 W, IMT-2000 Mobile Station

NHS-DLT, Antenna Elevation Angle: 10°, Transmitter Power: 1,000 W, IMT-2000 Mobile Station
26

NHS-B, Antenna Elevation Angle: 10°, Transmitter Power: 2,500 W, IMT-2000 Mobile Station

NHS-A, Antenna Elevation Angle: 10°, Transmitter Power: 10,000 W, IMT-2000 Mobile Station
27

Topography Around OAS, San Jose, California
28

OAS, Antenna Elevation Angle: 3°, Transmitter Power: 100 W, IMT-2000 Base Station

OAS, Antenna Elevation Angle: 3°, Transmitter Power: 2,000 W, IMT-2000 Base Station
29

OAS, Antenna Elevation Angle: 5°, Transmitter Power: 100 W, IMT-2000 Base Station

OAS, Antenna Elevation Angle: 5°, Transmitter Power: 2,000 W, IMT-2000 Base Station
30

OAS, Antenna Elevation Angle: 10°, Transmitter Power: 100 W, IMT-2000 Base Station

OAS, Antenna Elevation Angle: 10°, Transmitter Power: 2,000 W, IMT-2000 Base Station
31

OAS, Antenna Elevation Angle: 3°, Transmitter Power: 100 W, IMT-2000 Mobile Station

OAS, Antenna Elevation Angle: 3°, Transmitter Power: 2,000 W, IMT-2000 Mobile Station
32

OAS, Antenna Elevation Angle: 5°, Transmitter Power: 100 W, IMT-2000 Mobile Station

OAS, Antenna Elevation Angle: 5°, Transmitter Power: 2,000 W, IMT-2000 Mobile Station
33

OAS, Antenna Elevation Angle: 10°, Transmitter Power: 100 W, IMT-2000 Mobile Station

OAS, Antenna Elevation Angle: 10°, Transmitter Power: 2,000 W, IMT-2000 Mobile Station
34

Topography Around EVCF, Melbourne, Florida
35

EVCF, Antenna Elevation Angle: 3°, Transmitter Power: 100 W, IMT-2000 Base Station

EVCF, Antenna Elevation Angle: 3°, Transmitter Power: 2,250 W, IMT-2000 Base Station
36

EVCF, Antenna Elevation Angle: 5°, Transmitter Power: 100 W, IMT-2000 Base Station

EVCF, Antenna Elevation Angle: 5°, Transmitter Power: 2,250 W, IMT-2000 Base Station
37

EVCF, Antenna Elevation Angle: 10°, Transmitter Power: 100 W, IMT-2000 Base Station

EVCF, Antenna Elevation Angle: 10°, Transmitter Power: 2,250 W, IMT-2000 Base Station
38

EVCF, Antenna Elevation Angle: 3°, Transmitter Power: 100 W, IMT-2000 Mobile Station

EVCF, Antenna Elevation Angle: 3°, Transmitter Power: 2,250 W, IMT-2000 Mobile Station
39

EVCF, Antenna Elevation Angle: 5°, Transmitter Power: 100 W, IMT-2000 Mobile Station

EVCF, Antenna Elevation Angle: 5°, Transmitter Power: 2,250 W, IMT-2000 Mobile Station
40

EVCF, Antenna Elevation Angle: 10°, Transmitter Power: 100 W, IMT-2000 Mobile Station

EVCF, Antenna Elevation Angle: 10°, Transmitter Power: 2,250 W, IMT-2000 Mobile Station
41

HTS Topography

HTS, Antenna Elevation Angle: 5°, Transmitter Power: 2000 W, IMT-2000 Base Station
42

HTS, Antenna Elevation Angle: 5°, Transmitter Power: 2000 W, IMT-2000 Mobile Station

HTS, Antenna Elevation Angle: 10°, Transmitter Power: 500 W, IMT-2000 Mobile Station
43

Guam Topography

GTS, Antenna Elevation Angle: 3°, Transmitter Power: 7000 W, IMT-2000 Base Station
44

GTS, Antenna Elevation Angle: 10°, Transmitter Power: 100 W, IMT-2000 Mobile Station
Department of Defense

United States Army

United States Marines Corps

United States Navy

United States Air Force

Requests for copies of this document shall be referred to Defense Information

Systems Agency, Office of Spectrum Analysis and Management.