NTIA Report 05-432 

INTERFERENCE PROTECTION CRITERIA 

 Phase 1 - Compilation from Existing Sources 

technical report 

U.S. DEPARTMENT OF COMMERCE  National Telecommunications and Information Administration 

NTIA Report 05-432 

INTERFERENCE PROTECTION CRITERIA 

Phase 1 - Compilation from Existing Sources 

Alakananda Paul 

Gerald Hurt 

Thomas Sullivan 

Gary Patrick 

Robert Sole 

Larry Brunson 

Cou-Way Wang 

Bernard Joiner 

Edward Drocella 

Contributors 

Suzette Williams 

Gentiana Saam

U.S. Department of Commerce 

Carlos M. Guiterrez, Secretary 

Michael D. Gallagher, Assistant Secretary 

for Communications and Information 

October 2005 

EXECUTIVE SUMMARY 

The National Telecommunications and Information Administration (NTIA) 

launched this two-phase study of interference protection criteria (IPC) in order to 

compile, explain and validate, modify or supplement the levels of protection from 

interference that are generally expected and provided for various radiocommunication 

systems. The study is an integral part of President Bush’s Spectrum Policy Initiative 

that was established in May 2003 to promote the development and implementation of a 

United States spectrum policy for the 21st century. The Secretary of Commerce then 

established a Federal Government Spectrum Task Force and initiated a series of public 

meetings to address improvements in policies affecting spectrum use by the Federal 

Government, State, and local governments, and the private sector. The 

recommendations resulting from these activities were included in a two-part series of 

reports released by the Secretary of Commerce in June 2004, under the title Spectrum 

Policy for the 21st Century - The Presidents Spectrum Policy Initiative. Based on the 

recommendations contained in these Reports, the President directed the federal 

agencies on November 30, 2004, to plan the implementation of the 24 

recommendations contained in the Reports. There were several recommendations that 

will consider the interference protection criteria contained in this study including: 

• assessment of new technologies and their impact on incumbent 

radiocommunications; 

• managing interference; 

• development of a “Best Practices Handbook” for spectrum engineering; 

• establishment a pilot program and long-range plan for improved sharing of 

spectrum between federal and non-federal entities; and 

• creation of new analytical computer models that will facilitate spectrum 

engineering. 

The U.S. spectrum management process has evolved to meet the rapidly 

changing spectrum requirements of both the private sector and the federal government. 

Within this spectrum management process, the Federal Communications Commission 

(FCC), acting on behalf of the private sector, and the NTIA, acting on behalf of the 

federal agencies, provide spectrum planning, allocation and assignment in a manner 

that prevents interference. In the last five to ten years, spectrum usage and demand 

have increased significantly. Associated with the increased spectrum usage demand, 

came the increased geographic densities of transmitters and receivers, that means 

increased interference risks. One of the key elements in preventing interference is 

identification of the appropriate IPC. Implementation of a new technology often requires 

a significant amount of time to define and obtain agreement on an appropriate IPC. For 

example, it took several years to obtain sufficient measurement and analytical 

information on potential interference from ultrawideband (UWB) devices in order to 

define and apply the necessary IPC. To speed up the introduction of a new technology 

associated with the addition of licensed or unlicensed operations, means that 

advocates, incumbents and regulators will have to find more effective ways for 
ii 

analyzing the potential interference in a more timely manner. To this end, it is 

appropriate to predict and define the interfering signal levels at which radio systems 

may experience unacceptable degradation in performance, and to establish methods for 

protection of radio communications from interference. 

One of the key steps in any interference, electromagnetic compatibility, or 

spectrum sharing study is identifying IPC, to determine the necessary distance or 

frequency separations, or other frequency sharing constraints. The identification of IPC 

is often a confusing, time-consuming step with no single reference source from which to 

draw. The complexity of this process is exacerbated by the numerous terms used to 

define interference. For example, the NTIA, FCC, and International Telecommunication 

Union, Radiocommunication Sector or (ITU-R), define various terms relative to 

interference, including: Interference, Permissible Interference, Accepted Interference, 

and Harmful Interference. The diverse concepts behind these terms can lead to 

confusion when addressing potential interference between systems. Furthermore, since 

IPC normally depend upon details of the interfering and interfered-with systems as well 

as their operating environments, a very large number of combinations of frequency 

sharing situations must be considered with regard to a proposed new service or 

technology. 

NTIA reviewed publications of national, international, public and private 

organizations to compile established IPC for various radio services operating between 

30 MHz and 30 GHz. The results are presented in this Phase 1 report. One common 

feature was that for continuous, long-term interfering signal levels, nearly all established 

IPC were based on an interference-to-noise power ratio of –6 to –10 dB. Short-term 

IPC that accommodate relatively high interfering signal levels for small percentages of 

time or locations were not found for many services. For pulsed or intermittent interfering 

signals, the IPC for many of the radio services were not specified or the available IPC 

varied due to the specific types of desired and interfering signals being received. 

In the second phase of this study, NTIA will review the relevant federal 

government policies and practices regarding IPC and recommend regulatory and 

technical refinements that may improve IPC application’s scope, utility, clarity, or 

effectiveness. 
iii 

ACRONYMS AND ABBREVIATIONS 

 

AFTRCC Aerospace and Flight Test Radio Coordinating Council 

AI Articulation Index 

AMSS Aeronautical Mobile-Satellite Service 

AMS(OR)S Aeronautical Mobile-Satellite Service (Off-route) 

AMS(R)S Aeronautical Mobile-Satellite Service (Route) 

ANSI American National Standards Institute 

AP30 Appendix 30 of the ITU Radio Regulations 

APCO Association of Public-Safety Communications Officials 

APT Automatic Picture Transmission 

ARINC Aeronautical Radio Incorporated 

ATCRBS Air Traffic Control Radar Beacon System 

ATM Air Traffic Management 

ATPC Automatic Transmitter Power Control 

ATSC Advanced Television Systems Committee 

BBER Background Block Error Ratio 

BEP Bit Error Probability 

BER Bit Error Ratio 

BS Broadcasting Service 

BSS Broadcasting-Satellite Service 

BW Bandwidth 

C/A Coarse Acquisition 

CATV Community Antenna Television 

CCIR International Radio Consultative Committee (now called 

“ITU-R”) 

CDA Command and Data Acquisition System 

CD Color Decoding 

CDMA Code Division Multiple Access 

CEPT European Conference of Postal and Telecommunications 

Administrations 

CFR Code of Federal Regulations 

C/I Carrier-to-Interfering Signal Power Ratio 

C/(I+N) Carrier-to-Interference-plus-Noise Power Ratio 

C/N Carrier-to-Noise Power Ratio 

CW Continuous Wave 

DAQ Delivered Audio Quality 

dB Decibel 

dBi Antenna gain in dB over isotropic 

dBic Antenna gain in dB over isotropic (circular polarized) 

dBm Power in dB referred to 1 milliwatt 

dBμ Field strengths in dB above one microvolt per meter 

DBS Direct Broadcast Satellite 

dBW Power in dB referred to 1 watt 

dBZ Radar reflectivity factor in dB 
iv 

DME Distance Measuring Equipment 

DMS Digital Microwave System 

DNR Draft New Recommendation 

DOD Department of Defense 

DRS Data Relay Satellite 

DTV Digital Television 

D/U Desired-To-Undesired Signal Power Ratio 

DVB-T Digital Video Broadcasting-Terrestrial 

ECC Electronic Communications Committee 

EES Earth Exploration-Satellite 

EIA Electronics Industry Alliance 

EMC Electromagnetic Compatibility 

ERO European Radiocommunications Organization 

ESR Errored Second Ratio 

ETSI European Telecommunications Standards Institute 

EVA Extra-Vehicular Activity 

FAA Federal Aviation Administration 

FCC Federal Communications Commission 

FDMA Frequency Division Multiple Access 

FDP Fractional Degradation of Performance 

FEC Forward Error Correction 

FH Frequency Hopping 

FM Frequency Modulation 

FS Fixed Service 

FSS Fixed-Satellite Service 

GHz Gigahertz (109

 Hertz) 

GLONASS Global Navigation Satellite System (Russian) 

GNSS Global Navigation Satellite System 

GPS Global Positioning System 

GRD Global Recorded Data 

GSO Geostationary Satellite Orbit 

HDTV High Definition Television 

HRDP Hypothetical Reference Digital Path 

HRPT High Resolution Picture Transmission 

Hz Hertz 

IBOC In-band on-channel 

ICAO International Civil Aviation Organization 

IEC International Electrotechnical Commission 

IEEE Institute of Electrical and Electronics Engineers 

ILS Instrument Landing System 

IMO International Maritime Organization 

IMT-2000 International Mobile Telecommunications-2000 

I/N Interfering-to-Noise Power Ratio 

IP Internet Protocol 

IPC Interference Protection Criteria 

ISDB-T Integrated Service Digital Broadcasting-Terrestrial 
v 

ISDN Integrated Services Digital Network 

ISM Industrial, Scientific, and Medical 

ITU International Telecommunication Union 

ITU-R ITU Radiocommunication Sector 

ITU-T ITU Telecommunications Standardization Sector 

JSC Joint Spectrum Center 

JTF Joint Task Force 

K Kelvin 

Kbps Kilobits per second 

kHz Kilohertz (103 Hertz) 

LMSS Land Mobile-Satellite Service 

LEO Low Earth Orbit 

LRPT Low Resolution Picture Transmission 

m Meter 

Mb/s Megabits per second 

MEA Multiple Exposure Allowance 

METSAT Meteorological-Satellite 

MHz Megahertz (106

 Hertz) 

MIL-STD Military Standard 

MLS Microwave Landing System 

MMSS Maritime Mobile-Satellite Service 

MS Mobile Service 

MSS Mobile-Satellite Service 

MVDDS Multi-Channel Video Distribution and Data Service 

N/C Noise-to-Carrier Ratio 

NGSO Non-Geostationary Satellite Orbit 

NIB Non-Interference-Basis 

NPRM Notice of Proposed Rulemaking 

N/S Not Specified 

NTIA National Telecommunications and Information 

Administration 

NTSC National Television Standards Committee 

NWS National Weather Service 

NWP Numerical Weather Prediction 

OSM Office of Spectrum Management 

OSS One-Stop-Shopping Procedure 

PCM Pulse Code Modulation 

pfd Power Flux Density 

PLMR Private Land Mobile Radio 

QPSK Quadrature Phase Shift Keying 

RA United Kingdom Radiocommunications Agency 

RAS Radio Astronomy Service 

Rec Recommendation 

RF Radio Frequency 

RMS Root Mean Square 

RNSS Radionavigation-Satellite Service 
vi 

RR Radio Regulations 

RTCA Radio Technical Commission on Aeronautics 

RTCM Radio Technical Commission on Maritime 

SAR Synthetic Aperture Radars 

SCPC Single Channel Per Carrier 

SESR Severely Errored Second Ratio 

SG Study Group 

S/I Signal-to-Interference Power Ratio 

SINAD Signal to Interference, Noise, and Distortion Power Ratio 

SPTF Spectrum Policy Task Force 

TACAN Tactical Air Navigation 

TBD To Be Determined 

TDMA Time Division Multiple Access 

TIA Telecommunications Industry Association 

TSB Telecommunications Systems Bulletin 

UHF Ultra High Frequency – 300 to 3000 MHz 

USCG United States Coast Guard 

UWB Ultrawideband 

VHF Very High Frequency – 30 to 300 MHz 

VLBI Very Long Baseline Interferometry 

VOR Very-High-Frequency Omnidirectional Range 

VSAT Very Small Aperture Terminal 

WAAS Wide Area Augmentation System 

WEFAX Weather Facsimile 

WMO World Meteorological Organization 

WP8B ITU-R Working Party 8B 

WRC World Radiocommunication Conference 
vii 

TABLE OF CONTENTS 

EXECUTIVE SUMMARY I

ACRONYMS AND ABBREVIATIONS III

TABLE OF CONTENTS VII

SECTION 1 INTRODUCTION 1-1

1.1 BACKGROUND 1-1

1.2 OBJECTIVE 1-4

1.3 PHASE 1 APPROACH 1-5

1.4 SCOPE 1-5

SECTION 2 TECHNICAL PERSPECTIVES 2-1

2.1 INTRODUCTION 2-1

2.2 RELEVANT DEFINITIONS 2-1

2.3 ELEMENTS OF INTERFERENCE PROTECTION CRITERIA 2-2

SECTION 3 OVERVIEW 3-1

3.1 INTRODUCTION 3-1

3.2 FIXED AND FIXED-SATELLITE SERVICES 3-1

3.3 RADIODETERMINATION AND RADIODETERMINATION-SATELLITE 

SERVICES 3-1

3.4 BROADCASTING AND BROADCASTING-SATELLITE SERVICES 3-2

3.5 MOBILE AND MOBILE-SATELLITE SERVICES 3-2

3.6 SCIENCE SERVICES 3-3

SECTION 4 FIXED AND FIXED-SATELLITE SERVICES 4-1

4.1 INTRODUCTION 4-1

4.2 FIXED SERVICE 4-1

4.2.1 General 4-1

4.2.2 System Characteristics and Performance Objectives 4-1

4.2.3 Interference Protection Criteria 4-3

4.2.4 Possible Mitigating Factors 4-8

4.3 FIXED-SATELLITE SERVICE 4-9

4.3.1 General 4-9

4.3.2 System Characteristics and Performance Objectives 4-9

4.3.3 Error Performance Objective 4-11

4.3.4 Interference Protection Criteria Summary 4-14

4.4 SUMMARY 4-16
viii 

SECTION 5 RADIODETERMINATION AND RADIODETERMINATION-SATELLITE 

SERVICES 5-1

5.1 INTRODUCTION 5-1

5.2 RADIODETERMINATION SERVICE 5-1

5.2.1 Radars operated in the Radiolocation, Aeronautical Radionavigation, 

Meteorological Aids, and Maritime Radionavigation Services 5-1

5.2.2 CW and Noise-like Interfering Signals 5-2

5.2.3 Pulse-Like Interfering Signals 5-3

5.2.4 Impulse-Like Interfering Signals 5-3

5.2.5 Aeronautical Radionavigation Systems (other than radars using passive 

reflections) 5-4

5.3 RADIONAVIGATION-SATELLITE SERVICE 5-5

5.3.1 IPC Values for GPS Receivers 5-6

SECTION 6 BROADCASTING AND BROADCASTING-SATELLITE SERVICES 6-1

6.1 INTRODUCTION 6-1

6.2 BROADCASTING SERVICE 6-1

6.2.1 Broadcast Television 6-2

6.2.2 FM Radio Broadcast 6-7

6.3 BROADCASTING-SATELLITE SERVICE 6-9

6.3.1 Appendix 30 (AP30) of the ITU Radio Regulations 6-11

6.3.2 Recommendation ITU-R BO.1297 6-13

6.3.3 Recommendation ITU-R BO.1444 6-13

6.3.4 FCC Report and Order 00-418 6-14

6.3.5 Mitre Technical Report 6-14

6.3.6 Spectrum XXI 6-15

6.3.7 Further Study 6-15

6.4 SUMMARY 6-16

SECTION 7 MOBILE AND MOBILE SATELLITE SERVICES 7-1

7.1 INTRODUCTION 7-1

7.2 MOBILE SERVICE 7-1

7.2.1 Mobile Service in General 7-1

7.2.2 Land Mobile Service 7-3

7.2.3 Maritime Mobile Service 7-5

7.2.4 Aeronautical Mobile Service 7-6

7.3 MOBILE SATELLITE SERVICE 7-7

7.3.1 Geostationary Satellite Service 7-7

7.3.2 Nongeostationary Satellite Service - Downlink 7-8

7.3.3 NGSO Satellite Service (Cospas-Sarsat Uplink) 7-8

7.4 SUMMARY 7-8

SECTION 8 SCIENCE SERVICES 8-1
ix 

8.1 INTRODUCTION 8-1

8.2 SPACE RESEARCH SERVICE 8-1

8.2.1 Deep-Space Research 8-1

8.2.2 Near Earth Space Research 8-3

8.2.3 Data Relay Satellites 8-4

8.2.4 Telecommunication Links in the 37-40 GHz Bands 8-4

8.3 SPACE OPERATION SERVICE 8-5

8.4 METEOROLOGICAL AIDS 8-5

8.5 EARTH EXPLORATION-SATELLITE AND METEOROLOGICAL SATELLITE 

SERVICES 8-6

8.5.1 Space-to-Earth Data Transmission Systems Using Low-Earth Orbit 8-6

8.5.2 Data Dissemination and Direct Data Readout Systems Using Geostationary 

Satellites 8-7

8.5.3 Service Links in Data Collection Systems 8-7

8.5.4 Command and Data Transmission System 8-7

8.5.5 Satellite Passive Remote Sensing 8-8

8.5.6 Spaceborne Active Microwave Remote Sensors 8-8

8.6 RADIO ASTRONOMY 8-9

8.7 SUMMARY 8-10
x 

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1-1 

SECTION 1 

INTRODUCTION 

1.1 BACKGROUND 

The National Telecommunications and Information Administration (NTIA) 

is the Executive Branch agency responsible for developing and articulating 

domestic and international telecommunications policy. NTIA acts as the principal 

advisor to the President on telecommunications policies pertaining to the nation’s 

economic and technological advancement and regulation of the 

telecommunications industry. NTIA is also responsible for managing the federal 

government’s use of the radio spectrum. Federal agencies are highly dependent 

on interference-free spectrum access to support a wide variety of critical 

missions including weather forecasting and homeland security. 

The spectrum management process, originally established under the 

Communications Act of 1934,has been frequently faced with rapidly changing 

perceived spectrum requirements of both the private sector and the federal 

government. The Federal Communications Commission (FCC), and NTIA have 

coordinated their spectrum management efforts to ensure that policies, rules, and 

practices for spectrum usage adequately prevent interference. 

 

One of the primary goals in spectrum management is to plan, allocate and 

assign spectrum in a way that prevents interference. This goal was discussed at 

NTIA’s April 2002 Spectrum Summit of the federal and private sector spectrum 

management community as well as the radio service users and providers. In 

parallel, the FCC created a Spectrum Policy Task Force (SPTF) that focused on 

a number of issues, including interference, and formed an Interference Protection 

Working Group (IPWG). This forum posed several relevant questions. For 

example, how does one determine whether interference is harmful? What are the 

property rights of the licensed or assigned user? What are the property rights 

relative to freedom from interference? Many participants indicated that answers 

need to be developed with a clear view of the necessary spectrum management 

policies and conditions under which interference will be prevented. 

On June 6, 2002, the FCC SPTF issued a public notice seeking comment 

on issues related to the FCC’s spectrum policies.1

 The IPWG held several public 

workshops where the public was invited to present input. Over forty-eight 

companies provided comments on interference protection, suggesting that both 

licensed and unlicensed spectrum users should have clearly defined rights and 

obligations relating to interference. Participants also suggested that the United 

States integrates its domestic and international spectrum policy efforts on 

interference and concluded that interference protection was at the heart of many 

contentious debates before the FCC and NTIA. Furthermore, commenters 
1-2

suggested that both agencies should recognize and address several key 

interference principles:2

• some level of interference can be tolerated, which varies depending on the 

nature of the service involved and the nature of the interference; 

• due to advances in digital signal processing and antenna technology, 

communications systems and devices are becoming more tolerant of 

interfering signals through their ability to sense and adapt to the RF 

environment; 

• all systems require some degree of margin to ensure reliable 

communications; the regulators should not assume that eliminating that 

margin is acceptable; 

• the regulations and practices of interference protection differ between 

different radio services, with the rules of some services prescribing 

detailed criteria for predicting interference; 

• the regulators should consider interfering signal aggregation of multiple 

sources; 

• harmful interference is an extreme level and that just because interference 

does not rise to that level, it cannot be concluded that the interference is 

acceptable to the victim; and 

• the FCC should make clear that its spectrum policies are based on an 

“interference-limited” rather than “ambient noise-limited” environment. 

The SPTF provided a report of its findings and recommendations to the FCC in 

November 2002.3

In the last five to ten years, spectrum usage and demand have increased 

significantly. The major interference issues have required a substantial time to 

define and resolve. For example, in adopting rules for implementing the new 

technology referred to as ultrawideband (UWB), it took several years to obtain 

measurement and analytical information on interference susceptibility, sufficient 

to define the necessary Interference Protection Criteria (IPC). In order to 

accommodate new technologies and additional licensed and/or unlicensed 

operations more quickly, advocates, incumbents and regulators will have to find 

better ways to analyze the interference potential. Moreover, system designers 

need guidance on the levels of interfering signals that should be tolerated. To 

this end, it is appropriate to further define IPC. 

The identification of the appropriate IPC is often a confusing, timeconsuming process that is not supported by a single reference source. This 

process is further complicated by numerous relevant regulatory and technical 

terms. For example, the NTIA, FCC, and the International Telecommunication 

Union, Radiocommunication Sector, (ITU-R) define several terms relative to 

interference, including: Interference, Permissible Interference, Accepted 

Interference, Harmful Interference, and Protection Ratios. Other terms that are 

commonly used, but not specifically defined are: Allowable Performance 
1-3

Degradation, Interference Protection Criteria, and Spectrum Sharing Criteria. 

Furthermore, since spectrum-sharing criteria normally depend upon parameters 

of both the interfering and interfered-with systems and their operating 

environments, a very large number of combinations is possible. Consideration of 

interference is “at least a six dimensional problem, meaning spatial, x-y-z, 

frequency, time, and waveform, and of course since the waveform can be 

infinitely complicated, you can make it an n-fold problem, which basically has 

more variables than you have numbers.”4

In 1990, International Telecommunication Union, Radiocommunication 

sector, Study Group 1 attempted to reduce this complexity by adopting Rec. ITUR SM.669 that includes a matrix of protection ratios for various combinations of 

interfering and desired-signal modulation types.5 An earlier, but more 

comprehensive approach was undertaken jointly by NTIA and the Department of 

Defense (DOD) Joint Spectrum Center (JSC), resulting in the publication of the 

Communications Receiver Performance Degradation Handbook.6 However, the 

IPC presented in Rec. ITU-R SM.669 as well as the Degradation Handbook have 

become largely obsolete for several reasons, including: 

 

1)The Degradation Handbook and Rec. ITU-R SM.669 focus on analog 

and early digital modulations, which are in many cases being supplanted by more 

complex, digital modulations. 

2) Both efforts focused primarily on modulation with little regard to radio 

service requirements or factors stemming from the operating frequency, whereas 

most spectrum sharing studies today focus primarily on radio services and 

specific frequency bands. 

3) The IPC in these texts do not include temporal or spatial statistical 

allowances that should be considered in detailed analyses. 

Since the adoption of Rec. ITU-R SM.669 and completion of the 

Degradation Handbook, extensive spectrum sharing studies have been 

completed and documented within the International Telecommunication Union, 

Radiocommunication sector, and elsewhere. As part of on-going spectrum 

sharing studies within the International Telecommunication Union, 

Radiocommunication sector, the various service study groups have refined and 

documented IPC for their respective radio services within numerous International 

Telecommunication Union, Radiocommunication sector Recommendations. In 

light of these developments, NTIA launched a study of IPC. This Phase 1 report 

compiles available IPC. In the second phase of this study, NTIA will review the 

relevant federal government policy and practices regarding derivation of IPC, and 

recommend regulatory and technical refinements that may improve IPC 

application’s scope, utility, clarity, or effectiveness. 
1-4

1.2 OBJECTIVE 

 The National Telecommunications and Information Administration (NTIA) 

launched a two-phase study of interference protection criteria (IPC) to compile, 

explain and validate, modify or supplement the levels of protection from 

interference that are generally expected and provided for various 

radiocommunication systems. 

 The study is an integral part of President Bush’s Spectrum Policy Initiative 

that was established in May 2003 to promote the development and 

implementation of a United States spectrum policy for the 21st century. The 

Secretary of Commerce then established a Federal Government Spectrum Task 

Force and initiated a series of public meetings to address improvements in 

policies affecting spectrum use by the Federal Government, State, and local 

governments, and the private sector. The recommendations resulting from these 

activities were included in a two-part series of reports released by the Secretary 

of Commerce in June 2004, under the title Spectrum Policy for the 21st Century - 

The Presidents Spectrum Policy Initiative. Based on the recommendations 

contained in these Reports, the President directed the federal agencies on 

November 30, 2004, to plan the implementation of the 24 recommendations 

contained in the Reports. There were several recommendations that will 

consider the interference protection criteria contained in this study including: 

• assessment of new technologies and their impact on incumbent 

radiocommunications; 

• managing interference; 

• development of a “Best Practices Handbook” for spectrum engineering; 

• establishment a pilot program and long-range plan for improved sharing of 

spectrum between federal and non-federal entities; and 

• creation of new analytical computer models that will facilitate spectrum 

engineering. 

Based on the above, the objectives of this study are as follows: 

Phase 1: 

• Review publicly available texts to identify and document IPC for radio 

services that accommodate federal government radiocommunications and 

apply this information as applicable to the completion of the appropriate 

recommendations approved by President Bush. 

Phase 2: 

• Review federal government policy and practices regarding IPC and 

recommend regulatory refinements that may improve the scope, clarity or 
1-5

effectiveness of interference-protection provisions, as appropriate; 

• Review applications for IPC; 

• Develop a methodology for determining appropriate IPC that can be used 

to supplement, validate or refine existing IPC; 

 Additional objectives will be determined during Phase 2 of this study. 

These may include: 

• Apply the methodology for determining appropriate IPC to supplement or 

refine, as appropriate, IPC identified in Phase 1 to establish validated IPC 

for each radio service; 

• Incorporate findings in NTIA’s planned best practices handbook; 

• On a case-by-case basis, promote IPC and associated regulatory 

provisions for the private sector through rulemakings at the FCC; 

• Provide the results to ITU-R Study Group 1 for possible replacement of 

Rec. ITU-R SM.669. 

1.3 PHASE 1 APPROACH 

• Define IPC. 

• Compile IPC in five broad areas covering fixed and fixed-satellite services, 

radiodetermination and radiodetermination-satellite services, broadcasting 

and broadcasting–satellite services, mobile and mobile-satellite services, 

and science services. 

• Categorize IPC according to the type of interfering signal (continuous 

wave (CW), noise-like, pulse, and other) and, where available, associated 

statistical allowances (long-term or short-term). 

• Document results in an NTIA Phase 1 report. 

1.4 SCOPE 

This report includes IPC covering the frequency range 30 MHz to 30 GHz. 

Numerous sources of IPC are available from international agencies, government 

agencies, trade associations, academic institutions, and others. This report 

compiles IPC from generally accepted sources. The sources considered were as 

follows: 
1-6

• ITU-R. A role of the ITU-R is to provide guidance for the rational, 

equitable, efficient, and economical use of the radio-frequency spectrum 

by all radiocommunication services. The ITU-R carries out studies 

culminating in Recommendations, which serve as a repository of technical 

and procedural guidelines for the design, implementation and operation of 

radiocommunications systems. The ITU-R Study Groups (SG) listed 

below focus on particular radiocommunications services, as do the 

subsequent sections of this report. Working parties are established within 

each Study Group to address service issues such as performance 

objectives. 

 SG 1 - Spectrum management 

 SG 3 - Radiowave propagation 

 SG 4 - Fixed-satellite service 

 SG 6 - Broadcasting service 

 SG 7 - Science services 

 SG 8 - Mobile, radiodetermination, amateur and related satellite 

services 

 SG 9 - Fixed service 

• International Civil Aviation Organization (ICAO). One of the chief activities 

of the ICAO is the establishment of International Standards, 

Recommended Practices and Procedures covering the technical fields of 

aviation including aeronautical telecommunications, air traffic services, 

search and rescue, navigation, surveillance, and aeronautical information 

services. The principle document considered herein is the ICAO 

International Standards and Recommended Practices. 

• International Maritime Organization (IMO). The IMO was established with 

the chief task of developing a comprehensive body of the international 

conventions, codes and recommendations to be implemented by all 

member governments. The Maritime Safety Committee has subcommittees dealing with relevant subjects, including safety of navigation, 

radiocommunications and search and rescue. 

• International Electrotechnical Commission (IEC). The IEC is a global 

organization that prepares and publishes international standards for all 

electrical, electronic and related technologies. These serve as a basis for 

national standardization and as references when drafting international 

tenders and contracts. 

• World Meteorological Organization (WMO). The WMO coordinates global 

scientific activity to allow increasingly prompt and accurate weather 

information services for public, private and commercial use, including 

international airline and shipping industries. WMO's major scientific and 

technical programs include the World Weather Watch, which offers up-to-
1-7

the-minute world-wide weather information through member-operated 

observation systems and telecommunication links (presently using four 

polar-orbiting and five geostationary satellites, about 10,000 land 

observation stations, 7,000 ship stations and 300 moored and drifting 

buoys carrying automatic weather stations). 

• European Radiocommunications Organization (ERO). ERO is the 

permanent office supporting the Electronic Communications Committee 

(ECC) of the European Conference of Postal and Telecommunications 

Administrations (CEPT). ECC is the Committee that brings together the 

radio and telecommunications regulatory authorities of the 45 CEPT 

member countries. 

• National Telecommunications and Information Administration (NTIA). 

NTIA is the Executive Branch agency principally responsible for 

developing and articulating domestic and international telecommunications 

policy as well as managing and regulating federal government use of the 

spectrum. Accordingly, NTIA conducts studies and makes 

recommendations regarding telecommunications matters to Congress, the 

FCC, and the public. NTIA rules and publications include the NTIA 

Manual and the library of reports produced by the Office of Spectrum 

Management (OSM) and the Institute for Telecommunication Sciences 

(ITS).7

• Federal Communications Commission (FCC). The FCC manages and 

regulates use of the spectrum by non-federal entities. The FCC rules and 

regulations are codified in Title 47 of the Code of Federal Regulations 

(CFR). 

• Joint Spectrum Center (JSC). JSC conducts various frequency sharing 

studies for the Department of Defense (DOD). The Joint Staff J-6 of DoD 

directed the JSC to develop Spectrum XXI as a Windows-NT based 

application to address the spectrum management requirements of the 

Force Commanders, the Joint Task Force (JTF) commanders, the Military 

Departments, and the sustaining base elements. Spectrum XXI uses a 

table containing IPC for many services that is based on NTIA reports, FCC 

Rules and Regulations, ITU-R Recommendations and Reports, the 

DOD/JSC Degradation Handbook, and industry standards. 

• Military Standards (MIL-STDs). MIL-STDs generally impose requirements 

and instructions on the military. They are written primarily for the benefit 

of program offices and product centers. Compliance may not be 

mandatory. MIL-STDs were found through searching the DOD Index of 

Specifications and Standards (DODISS). 

• RTCA Inc. (formallyTechnical Commission on Aeronautics). The RTCA 

Inc., is an association of aeronautical organizations from the United States 
1-8

and other countries that seeks sound technical solutions to problems 

involving the application of electronics and telecommunications to 

aeronautical operations. 

• Radio Technical Commission on Maritime (RTCM). The RTCM is 

chartered in the District of Columbia, as a non-profit scientific and 

educational organization, focusing on all aspects of maritime 

radiocommunications, radionavigation, and related technologies. 

Participants are from government and private sectors. Since its 

establishment in 1946, the RTCM has been supported by its member 

organizations to serve as a focal point to collect and distribute information, 

and to serve as a catalyst in developing solutions to both national and 

international maritime radiocommunications and radionavigation issues. 

• Telecommunications Industry Association (TIA). TIA, in conjunction with 

the Electronics Industry Alliance (EIA), sponsors committees of experts to 

prepare standards dealing with performance testing and compatibility. TIA 

is accredited by the American National Standards Institute (ANSI) to 

develop voluntary industry standards for a wide variety of 

telecommunications products. 

• Aerospace and Flight Test Radio Coordinating Council (AFTRCC). 

AFTRCC provides recommendations to the FCC for non-government use 

of flight test voice and telemetry frequencies. Its role is strictly advisory. 

• Association of Public-Safety Communications Officials (APCO). APCO is 

an international non-profit professional organization dedicated to the 

enhancement of public safety communications. It serves the people who 

manage, operate, maintain, and supply public safety communications 

systems mainly at the state level. 

• Institute of Electrical and Electronics Engineers (IEEE). IEEE is a nonprofit, technical professional association in 150 countries. The IEEE is a 

leading authority in technical areas such as computer engineering and 

telecommunications. Through its technical publishing, conferences and 

consensus-based standards activities, IEEE produces 30 percent of the 

world's published literature in electrical engineering, computers and 

control technology, holds annually more than 300 major conferences and 

has nearly 900 active standards with 700 under development. 

• The European Telecommunications Standards Institute (ETSI). ETSI is 

the technical standards body under the European Conference of Postal 

and Telecommunications Administrations (CEPT). It publishes European 

technical standards that are adopted by most regulatory authorities in 

Europe as well as in some non-European countries. Having common 
1-9

standards facilitates equipment testing and type acceptance in these 

countries. 

• United Kingdom Radiocommunications Agency (RA). RA was an 

executive agency of the Department of Trade and Industry, United 

Kingdom. It was responsible for the management of the non-military radio 

spectrum in the United Kingdom, which involves international 

representation, commissioning research, allocating spectrum and 

licensing its use. Recently, office of communicatons (OFCOM), has taken 

over these responsibilities and assumed the powers of the five former 

regulators it has replaced - the Broadcasting Standards Commission, the 

Independent Television Commission, OFTEL, the Radio Authority and the 

Radiocommunications Agency. OFCOM is the regulator for the United 

Kingdom communications industries, with responsibilities across 

television, radio, telecommunications and wireless communications 

services.

• Eurocontrol. Eurocontrol is an organization consisting of 41 European 

states whose mission is to co-ordinate the development of a uniform 

system of air traffic management throughout Europe. Eurocontrol works 

with its members in the air transport industry to provide a range of 

services, including air traffic controller training; managing air traffic flow; 

regional control of airspace to development of innovative technologies and 

procedures; and collection of air navigation charges, civil/military among 

other things. 
1-10

REFERENCES

1 Spectrum Policy Task Force Seeks Public Comment on Issues Related to 

Commission’s Spectrum Policies, Public Notice, ET Docket No. 02-135, DA-02-

1311, 17 F.C.C. Rca. 10560, Federal Communications Commission (2002). 

2 Spectrum Policy Task Force, Interference Protection Working Group Report 

(Working Group Report), ET Docket No. 02-135, at www.fcc.gov/sptf/, Federal 

Communications Commission ( 2002). 

3 Spectrum Policy Task Force Report, ET Docket No. 02-135, DOC-228542, 

Federal Communications Commission ( 2002). 

4

 Working Group Report, at 5 (Remarks by Dr. Paul Steffes). 

5 Protection Ratios for Spectrum Sharing Investigations, Rec. ITU-R SM. 669-1, 

(1994). 

6

 Communications Receiver Performance Degradation Handbook, 

Electromagnetic Compatibility Analysis Center, Annapolis, Maryland (1987). 

7 Manual of Regulations & Procedures for Federal Radio Frequency 

Management (Manual), National Telecommunications and Information 

Administration, at Chapter 6 (September 2003). 
1-11

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2-1 

SECTION 2 

TECHNICAL PERSPECTIVES 

2.1 INTRODUCTION 

This section provides an overview definitions and relevant terms related to 

interference and IPC. 

2.2 RELEVANT DEFINITIONS 

The ITU Radio Regulations (Article 1), NTIA Manual (Chapter 6), and FCC Rules 

and Regulations (Part 2), define several terms related to interference, including:1 

1.166 

Interference: The effect of unwanted energy due to one or a combination of emissions, 

radiations, or inductions upon reception in a radiocommunication system, manifested by 

any performance degradation, misinterpretation, or loss of information which could be 

extracted in the absence of such unwanted energy. 

1.167 

Permissible Interference: Observed or predicted interference which complies with 

quantitative interference and sharing criteria contained in these Regulations or in ITU-R 

Recommendations or in special agreements as provided for in these Regulations. 

1.168 

Accepted Interference: Interference at a higher level than that defined as permissible 

interference and which has been agreed upon between two or more administrations 

without prejudice to other administrations. 

1.169 

Harmful Interference: Interference which endangers the functioning of a 

radionavigation service or of other safety services or seriously degrades, obstructs, or 

repeatedly interrupts a radiocommunication service operating in accordance with these 

Regulations (CS).

1.170 

Protection Ratios (R.F.): The minimum value of the wanted-to-unwanted signal ratio, 

usually expressed in decibels, at the receiver input determined under specified 

conditions such that a specified reception quality of the wanted signal is achieved at the 

receiver output. 

 The following terms are not formally defined in any regulatory documents. These 

terms have been in common use, in NTIA. 
2-2

• Allowable Performance Degradation: Agreed upon degradation in the 

performance of a radiocommunication system due to interference that is at a 

sufficiently low level such that the performance capabilities are not significantly 

compromised. This is often defined in terms of a percentage change in a key 

performance measure such as voice circuit noise, outage time, or target 

detection probability. 

• Interference Protection Criteria (IPC): A relative or absolute interfering signal 

level defined at the receiver input, under specified conditions, such that the 

allowable performance degradation is not exceeded. This is usually defined as 

an absolute interference power level I, interference-to-noise power ratio I/N, or 

carrier-to-interfering signal power ratio C/I. 

• Sharing Criteria: Broadly defined criteria that ensure compliance with IPC by 

specifying technical and operational constraints that permit sharing of a given 

portion of the spectrum between two or more radio systems or services. 

2.3 ELEMENTS OF INTERFERENCE PROTECTION CRITERIA 

All of the IPC compiled herein specify permissible interference. IPC are specified 

for aggregate interfering signals (i.e., total from all interferers) or single-entry interfering 

signals (i.e., from one interfering system). Aggregate IPC are generally derived from 

performance objectives and may be used to define the potential interfering signal 

environment in system design or performance analyses. Single-entry IPC, in turn, are 

derived from aggregate IPC and are used as “spectrum sharing criteria” directly or as 

the basis for other forms of sharing criteria (e.g., transmitter power and antenna pointing 

limits). 

IPC for many services are quite dependent upon the specific type of interfering 

signal received. Nevertheless, a relatively small number of generic classes of 

interfering signal modulation can define bounding situations. These bounding cases 

include continuous wave (CW), noise-like, and pulse. For some services, interfering 

signals characterized as “impulse” and “same as desired signal” are included. 

Additionally, for some radio services, “short-term” and “long-term” IPC are specified. 

Table 2-1 summarizes these categories. 

IPC are generally given in terms of (C/I) ratios or power (I/N) ratios. The former 

defines the interfering signal level relative to a known carrier level, whereas the latter 

defines the level of interfering signal level relative to the system noise level. Some IPC 

directly specify interfering signal power levels. 
2-3

Table 2-1 

Interfering Signal Types Typically Specified With IPC 

Type of 

Interfering 

Signal 

Definition 

Continuous 

Wave (CW) 

A continuous signal with a bandwidth much smaller than 

the receiver baseband (output) bandwidth. 

Noise-Like 

A continuous signal that resembles Gaussian white noise 

over the RF bandwidth of the receiver (uniform power 

spectral density) or produces the same effect as such a 

signal. 

Pulse 

A signal that is turned on and off over time and can be 

described in terms of a pulse width and pulse repetition 

rate. The pulses may occur with a constant or changing 

repetition rate. 

Impulse 

A pulsed signal having a very short pulse width (often 

much less than a microsecond). In general, any pulsed 

signal having a pulse width much smaller than the impulse 

response of the receiver bandpass under consideration 

can be considered as an impulse signal. 

Same as Desired 

Signal 

All signal modulation parameters are the same as the 

desired signal except baseband information content 

(carrier frequencies may differ). 

Long-Term Interfering signal levels that are present most of the time, 

e.g., levels not exceeded for more than 80% of the time. 

Short-Term Interfering signal levels that are rarely exceeded, e.g., 

levels not exceeded for more than 99.9% of the time. 

For a given service and type of system, IPC must include the parameters listed in 

Table 2-2 in order to rigorously define the intended degree of protection from 

interference and enable application of the IPC with detailed, statistical analysis models. 

Omission of any of the parameters comprising complete IPC may prevent proper 

analysis of potential interference or performance and could yield less or more than the 

intended degree of protection. 
2-4

Table 2-2 

Parameters Needed to Fully Specify Aggregate 

and Single-Entry IPC 

IPC 

Parameter 

Typical 

Units 

Description 

Power 

Threshold 

dBm, 

dBW, 

dB 

One or more levels of interfering signal power I, I/N, or 

C/I. 

Reference 

Bandwidth 

Hz, 

kHz, 

MHz 

Bandwidth in which interfering signal power should be 

calculated or measured. 

Percentage 

of Time 

% For each threshold, the percentage of time during 

which the threshold should (C/I) or should not (I or I/N) 

be exceeded. 

Percentage 

of Locations 

% For each threshold, the percentage of locations at 

which the threshold should (C/I) or should not (I or I/N) 

be exceeded. Used in some services to protect 

operations within a service area. 

Special 

Conditions 

various Information needed for interpretation or application of 

the thresholds, including as a minimum: whether the 

IPC are for aggregate or single-entry interference; the 

type of interfering signal (e.g., noise-like) for which the 

IPC apply; and for I/N and C/I thresholds the definition 

of the N or C reference levels. May include duration of 

permissible threshold exceedance (e.g, # seconds); 

specific category of victim or interfering stations; and 

frequency off-tuning associated with the thresholds. 
2-5

REFERENCES

1

 ITU, Radio Radio Regulations, Geneva, Volume I, Article 1 (2001); Manual, at Chapter 

6; 47 C.F.R. § 2.1. 
2-6 

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3-1 

SECTION 3 

OVERVIEW 

3.1 INTRODUCTION 

This section contains an overview of the detailed findings presented in Sections 4 

through 8. At the end of each of these sections, a table presents a summary of the IPC 

values. 

3.2 FIXED AND FIXED-SATELLITE SERVICES 

Section 4 presents the IPCs for fixed services (FS) and fixed-satellite services 

(FSS) with a focus on digital modulation. For the FS, the discussion includes system 

characteristics and performance objectives of point-to-point, line-of-sight, digital 

microwave systems (DMS) and IPC values that have been adopted nationally or 

internationally. The technical parameters of DMS vary over a wide range and cannot be 

simply characterized. The performance of DMS is generally defined in terms of error 

performance and availability objectives. DMS are designed to achieve very low bit error 

ratios with typical per hop availability of 99.999% and higher. As a general rule, IPC 

values have been developed based on limiting performance degradation due to 

interference to a small percentage of the design objective values. IPC values for DMS 

are generally defined in ITU-R Recommendations in terms of I/N, whereas TIA Bulletins 

and FCC Regulations define the IPC in terms of C/I. For DMS, IPC values are 

presented in three categories: long-term CW and noise-like interfering signals, shortterm CW and noise-like interfering signals, and pulse interfering signals. 

For FSS, the discussion first presents representative FSS system characteristics 

and IPC defined in ITU-R texts for purposes of triggering frequency coordination. Then 

the desired signal qualities, specified in the form of error performance requirements, are 

discussed. The IPC are specified as an apportionment of the total noise allowance, 

while the total noise allowance is indirectly specified as the error performance 

requirement. Aggregate and single-entry IPC for both long-term and short-term 

interfering signal levels are given. 

3.3 RADIODETERMINATION AND RADIODETERMINATION-SATELLITE 

SERVICES 

Section 5 specifies IPC for systems operating in the radiodetermination and 

radionavigation satellite services in terms of an I/N, S/I, or interfering signal power level 

(I). The ITU has developed Part 4 of the M series of ITU-R Recommendations that 

contain the IPC for radars that rely on reflections or scattering from targets to perform 

their mission. These IPC are based on CW-like and noise-like interfering signals. 

 IPC do not consider the statistical nature of the interfering signal power levels and they 

do not differentiate between long and short-term interfering signal levels. Systems that 
3-2

employ a data link or a transponder have IPC based on an S/I or I forms of IPC. These 

IPC come from national and international aviation advisory committees. The IPC for 

these systems tends to be more conservative because they are intended to protect 

aircraft flight and landing operations under unfavorable circumstances. Depending on 

the system, the IPC can be for CW, noise, or pulse-like interfering signals. 

IPC for radionavigation satellite service (RNSS) were developed to protect 

receivers that are designed to use the Global Positioning System (GPS) and the Global 

Navigation Satellite System (GLONASS) operated by the United States, DOD and the 

Russian Federation to obtain position fixes and timing information. The ITU has 

developed IPC in the form of I levels for both GPS and GLONASS receivers that are 

contained in Part 5 of the M series of ITU-R Recommendations. The RTCA has 

developed IPC for aviation GPS receivers that are also based on I criteria. 

3.4 BROADCASTING AND BROADCASTING-SATELLITE SERVICES 

Section 6 discusses IPC for broadcasting services (BS) and the broadcastingsatellite services (BSS). The BS involves radio or television transmissions from 

terrestrial stations for direct reception by the general public. IPC for television are 

contained primarily in ITU-R Recommendations and FCC Rules. IPC for digital 

television apply to continuous and/or tropospheric interfering signals. These continuous 

interfering signals are long-term interfering signals at levels that are not exceeded for a 

large percentage of the time (e.g., 50%) and generally serve as the baseline for 

establishing protection criteria. Tropospheric interfering signals are short-term 

interfering signals at levels exceeded for no more than 1% to 10% of the time. 

FCC Rules addressing Frequency Modulation (FM) radio broadcasting define 

sharing criteria between FM radio stations in terms of minimum distance separations 

and do not specify general IPC values. IPC are given for interference between Very 

High Frequency (VHF) television channel 6 and FM radio broadcasting as well as 

between public safety (land mobile service) and television broadcasting. 

 

IPC for BSS systems are in the forms of C/I, I/N, or power flux density (pfd). 

They are found primarily in international texts. IPC are listed for both co-channel and 

adjacent channel interfering signal sources. In some cases, the adjacent channel IPC 

are a linear function of carrier frequency offset. IPC are specified for BSS service links 

(space-to-Earth) and their associated feeder links (Earth-to-space). The majority of IPC 

are for long-term interference protection although statistical approaches are being 

developed to provide short-term IPC. 

3.5 MOBILE AND MOBILE-SATELLITE SERVICES 

Section 7 discusses the IPC for mobile service (MS) and mobile-satellite service 

(MSS). The MS includes land mobile, maritime mobile, and aeronautical mobile 
3-3

services. IPC values provided for the MS in this document have been adopted 

nationally or internationally. They cannot be characterized simply since the majority of 

these IPC vary depending on the reference and do not contain all of the parameters 

required to fully define IPC (e.g., the percentage of time that an interfering signal level 

can be exceeded, type of interfering signal, single-entry versus aggregate). Most of the 

IPC are for co-channel operations. 

For land mobile applications, TIA Telecommunications Systems Bulletin (TSB) 

88-A provides a methodology to determine IPC in terms of the carrier-to-interferenceplus-noise power ratio (C/(I+N)) needed for satisfactory voice applications. Specifically, 

IPC for different desired signal modulation types may be calculated based on the power 

spectrum of the given signal modulations and Intermediate Frequency (IF) filter 

selectivity as well as the C/N required to fulfill the specific Channel Protection Criterion 

(CPC). TIA is currently developing IPC that could be applicable to data applications. A 

limited number of IPC values are available for the maritime and aeronautical services. 

For the MSS, the only source found for IPC is the ITU-R M series of 

Recommendations. ITU-R does not have MSS IPC specifications for analog desired 

signals. For MSS systems using the geostationary orbit, IPC are specified as an 

apportionment of the total noise, while the total noise is indirectly specified as the error 

performance requirement. For digital signals of MSS systems using non-geostationary 

orbits, IPC are specified in terms of the maximum aggregate interfering signal level at 

the input of the receive antenna, and the IPC values depend on the type of service, 

earth station antenna size, modulation, reference bandwidth, and access method. 

3.6 SCIENCE SERVICES 

Section 8 discusses IPC for science services. Science services include the 

space research service, inter-satellite service, space operations, meteorological aids 

service, Earth exploration-satellite (EES) service, meteorological-satellite (METSAT) 

service, and radio astronomy. These services support various missions including 

manned space flights and routine data collection. IPC for science services vary widely 

and are specified in ITU-R Recommendations. 

IPC for science services are generally given as the power spectral density for 

noise-like interfering signals or the total power of CW interfering signals at the receiver 

terminals in a specified frequency band. In some cases, both long-term and short-term 

IPC values are specified. In the case of radio astronomy, IPC are given in the form of 

power flux density. 
3-4

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4-1

SECTION 4 

FIXED AND FIXED-SATELLITE SERVICES 

4.1 INTRODUCTION 

The IPC for fixed services (FS) and fixed-satellites service (FSS) have 

been extensively studied and are well documented in the ITU-R 

Recommendations (S, F and SF Series) and publications issued by the TIA and 

others. As previously discussed, key factors that influence the establishment of 

IPC values include: emission type, allocation status of the interferer, and the 

duration of the interfering signal. This section discusses IPC for the FS and FSS 

with a focus on digital modulation. 

4.2 FIXED SERVICE 

4.2.1 General 

This sub-section addresses systems in the FS, specifically point-to-point 

DMS. The following paragraphs discuss source documents defining FS 

characteristics and performance objectives that are associated with IPC values 

that have been adopted nationally or internationally. Within this sub-section, all 

interfering signal power levels are based on the average power unless explicitly 

stated as peak power. 

 

4.2.2 System Characteristics and Performance Objectives 

The technical parameters of DMS vary over a wide range and cannot be 

simply characterized even within a given frequency band. Typical parameters 

and characteristics for DMS operating in bands from 800 MHz to 52 GHz are 

described in Appendix 7 of the ITU-R Radio Regulations Rec. ITU-R/ F.758, 

F.1101, F.1102 and TIA-TSB 10-F.1 Appendix 7 of the ITU-R Radio Regulations 

applies the values shown in Table 4-1 for certain DMS receiver parameters that 

are used in determination of coordination distances between transmitting earth 

stations and DMS. 
4-2

Table 4-1 

FS DMS Default Values in Appendix 7 of ITU-R Radio Regulations 

Interference Criteriaii

Band 

(GHz) 

Receive 

Antenna 

Gain 

(dBi) 

Noise 

Temperaturei

 (K) 

Fade 

Margin 

(dB) 

I

 iii 

(dBW/MHz) 

Percent of 

Time (%) 

1.4 33 750 33 –107 0.01 

1.6-2.7 35 750 33 –107 0.01 

5.7-8.4 46 750 37 –103 0.005 

10.7-11.5 50 1100 40 –98 0.005 

12.5-14.8 52 1100 40 –98 0.005 

17.7-19.7 48 1100 25 iv –113 0.005 

24.7-29.5 50 2000 25 iv –111 0.005 

40-51.4 42 2600 25 iv –110 0.005 

47.2-50.2 46 2000 25 iv –111 0.001 

71-95 45 2000 25 iv –111 0.002 

i. System noise temperature defined at the input to the antenna terminal. 

ii. These criteria are applicable to only short-term interfering signals. The 

interfering signal power I is to be exceeded for no more than the specified 

percentage of time. 

iii. I: level of permissible short-term interfering signal power per MHz from all 

sources that may be exceeded for no more than the indicated percentage of 

time. Levels are defined at the input to the antenna terminals. This is based on 

the methodology defined for short-term interfering signals in RR Appendix 7 for 

DMS as follows: I = receiver noise + fade margin (all values in dB). 

iv. These values are net fade margin assuming the use of automatic transmitter 

power control (ATPC). 

TIA TSB 10-F defines default values for several key parameters that may 

be used for frequency coordination purposes when more specific information is 

not available; these parameters and their default values are listed in Table 4-2. 

Table 4-2 

FS DMS Default Values in TIA TSB 10-F 

Parameter Default Value 

Per Hop Annual Path Availability Objective 99.999% 

2 GHz band 35 dB 

6 GHz band 40 dB 

11 & 13 GHz bands 45 dB 

Fade Margin at 10-6 BER 

18 GHz band 40 dB 

Receiver Noise Figure 5 dB 
4-3

The performance of DMS is generally defined in terms of error 

performance and availability objectives. The performance objectives defined in 

the ITU-R for the DMS systems implemented at the national level are defined by 

a series of recommendations, with the most important one from the standpoint of 

interference considerations being Rec. ITU-R F.1189.2

 In this Recommendation, 

each direction of a multi-hop DMS system should meet the performance 

objectives listed in Table 4-3. 

Table 4-3 

Error Performance Objectives of National FS DMS Systems 

Bit Rate 

(Mb/s) 1.5 to 5 >5 to 15 >15 to 55 >55 to 160 >160 to 3500 

Errored 

Second Ratio 

(ESR) 

0.04A 0.05A 0.075A 0.16A Under study 

Severely 

Errored 

Second Ratio 

(SESR) 

0.002A 0.002A 0.002A 0.002A 0.002A 

Background 

Block Error 

Ratio (BBER) 

2A x 10-4 2A x 10-4 2A x 10-4 2A x 10-4 A x 10-4

A = 0.015 + 0.01L/500 for long haul systems 

 = 0.08 for short haul and local access systems 

L = total length of DMS network, rounded up to the next multiple of 500 km 

For definition of ESR, SESR, and BBER, see Rec. ITU-R F.1189. 

4.2.3 Interference Protection Criteria 

As described above, DMS are designed to achieve very low bit error ratios 

with typical per hop availability of 99.999% or higher. Equivalent outage times 

are measured in seconds per month. As a rule, IPC values have been 

developed based on limiting degradation of performance due to interfering 

signals to a designated percentage of the overall degradation allowance. IPC 

values for DMS are generally defined in ITU-R documentation in terms of I/N, 

whereas TIA TSB 10-F and FCC Rules define the criteria in terms of C/I.3

 For 

DMS, IPC values have been discussed in three areas, namely, long-term 

interfering signal levels, short-term interfering signal levels, and pulse interfering 

signals; no information was identified regarding impulse forms of interfering 

signals. 

4.2.3.1 Long-Term Interfering Signals 

Virtually all available studies addressing interference to DMS consider low 

levels of CW, noise-like, and modulated interfering signals as all having the same 
4-4

impact on system performance. For DMS, long-term interfering signals refers to 

signal levels that are exceeded for 20% or more of the time. One common 

misconception is that typical DMS design features including high fade margins, 

forward error correction (FEC), and ATPC circuitry impart a degree of immunity 

to interfering signals. Both theory and practice show that this is not the case for 

continuous long-term interfering signals. Both the large fade margins and FEC 

circuitry (when employed) are key elements in achieving the high reliability 

objectives; continuous interfering signals simply add to system noise resulting in 

a reduction in link fade margin. 

Regardless of the amount of fade margin or type of FEC designed into the 

link, any reduction in fade margin due to interfering signals will lead to a 

reduction in performance. As discussed later, large fade margins and FEC may 

under certain conditions improve immunity to short-term and pulse interfering 

signals, respectively. ATPC can actually increase the vulnerability of a DMS 

receiver to short-term interfering signals. It should be recognized that 

operationally measuring long-term performance degradation due to interfering 

signals in FS systems is often difficult, or impractical, because of the very long 

measurement time period required. 

Permissible levels of interference in FS receivers are commonly defined 

differently depending on the source of the interference. A key ITU-R document 

that defines performance degradation is Rec. ITU-R F.1094, which describes 

three categories of interference sources to DMS, namely,4

 

• sources within the FS, 

• other services sharing the same band on a primary basis, and 

• other emissions and radiations from sources having lesser rights then FS. 

The latter includes sources such as secondary allocations, adjacent band 

emissions, unlicensed systems, and industrial, scientific, and medical (ISM) 

operations. 

The different IPC levels for these three interference categories are derived 

in that Recommendation by allocating 89%, 10%, and 1% of total allowable 

degradation to interfering signals from these three categories, respectively. 

These three categories of interference are discussed below. 

• Interference from Other FS Systems: 

In this category, I/N should not exceed –6 dB for more than 20% of 

any month. 

The methodology defined in Rec. ITU-R F.1094 allocates the largest 

amount of performance loss, 89%, to factors within the FS, including outage due 

to propagation fades, equipment breakdown, as well as interfering signals, but 
4-5

provides no further allocation among these factors. Therefore, this 

Recommendation does not provide specific guidance for FS interferers. 

TIA TSB 10-F is widely recognized domestically and is explicitly accepted 

by both FCC and NTIA for FS sharing. The IPC specified in TSB 10-F are based 

on an increase in total noise of 1 dB or, equivalently, a reduction in fade margin 

of 1 dB. In most FS bands, simultaneous interfering signals from multiple FS 

transmitters is considered rare and therefore, this criterion is commonly used as 

a single-entry interference criterion. An exception is the non-government bands 

at 6 and 11 GHz where high equipment densities occur resulting in possible 

multiple interfering signal exposures. A multiple exposure allowance (MEA) for 

these two bands is defined in TIA TSB 10-F as follows: 

(I/N)se = – 6 – MEA (dB) (4-1) 

where (I/N)se = single-entry long-term interference criteria, 

MEA = greater of {5, 10Log(BWC/BWI)}, 

BWC = receive bandwidth of victim carrier, 

BWI = transmit bandwidth of interferer. 

• Interference from Other Primary Allocated Services: 

In this category, I/N should not exceed –10 dB for more than 20% of 

any month. 

This level corresponds to a reduction in overall fade margin of about 0.4 

dB. It can be shown that, under certain conditions, an I/N of –10 dB corresponds 

to the 10% performance degradation defined in Rec. ITU-R F.1094 for sharing 

with other primary services. 

• Interference from Non-Primary Allocated Services: 

In this category, I/N should not exceed –20 dB for more than 20% of 

any month. 

Rec. ITU-R F.1094 allocates 1% of the total performance degradation to 

non-primary interfering signal sources. It can be shown that under certain 

conditions this corresponds to an I/N ratio of –20 dB. 

4.2.3.2 Short-Term Interfering Signals 

The effects of short-term interfering signal levels have been shown to 

differ depending on whether the DMS performance in the absence of interfering 

signals is limited mainly by multipath fading or rain fading. The former occurs in 

frequency bands below about 13 GHz and the latter above about 17 GHz, with a 
4-6

transition zone between these frequencies. 

• Below 13 GHz 

The generally accepted procedure for assessing the effects of short-term 

or time varying interfering signal levels on DMS performance in bands below 13 

GHz is found in Rec. ITUR F.1108.5 This methodology, called fractional 

degradation of performance (FDP), results in very simple equations for nondiversity DMS links as follows: 

 [(I/N)ave(dB)]/10 FDP = 10 (4-2) 

 

 (I/N)max ≤ 20 dB 

where FDP = Fractional degradation of performance (corresponds to 

the percentages defined in Rec. ITU-R F.1094), 

 (I/N)ave = I/N from all sources, averaged over a sufficiently long 

period of time to account for any periodicity in the 

interfering signal, 

 (I/N)max = Maximum instantaneous value of I/N. 

In this application, the average I/N does not refer to an average as may 

result from pulsed type interfering signals, but rather to a CW or noise-like 

interfering signals that are time varying or intermittent, such as a mobile 

transmitter or low orbiting satellite. Evaluated in this manner, the FDP 

methodology accounts for magnitudes of both long-term and short-term 

interfering signals in any combination. 

 

• Above 17 GHz 

Rec. ITU-R F.1495 describes IPC to protect the DMS from time varying 

aggregate interfering signal from other primary services in the 18 GHz band.6

 

These IPC include the following two constraints: 

I/N ≤ NFM – 5 (dB) not exceeded more than 0.01% of the time, 

≤ NFM – 1 (dB) not exceeded more than 0.0003% of the time, 

 

where NFM is the net fade margin taking into account any use of ATPC. 

 No standardized methodology was identified for the transition region 

between the above short percentages of time and long-term values. 
4-7

4.2.3.3 Pulse Interfering Signals 

The following discusses interference to DMS systems from pulse 

interfering signals. 

• DMS Not Employing Forward Error Correction 

As a rule, pulse interfering signal power should be evaluated in terms of 

peak envelope power over the entire necessary bandwidth of a radio channel of 

the interfered-with system.7

 Pulse interfering signals in DMS not employing FEC 

can often be just as damaging to performance, or nearly so, as a continuous 

noise-like interferer. However, except for the special case described below, few 

measurements or studies were identified that address pulse interfering signals to 

DMS not employing FEC. As default criteria, the criteria identified for noise-like 

interfering signals may be used for pulse interfering signals, but using the peak 

interfering signal power within the receiver passband. 

Rec. ITU-R F.1190 identifies IPC for DMS operated below 7 GHz from 

fixed and mobile radar systems. It did not take into account the possible use of 

FEC. Based on the fact that radar antenna mainbeams either rotate or 

continuously vary, the worst-case, peak interfering signal values only occur 

intermittently. Consequently, short-term interference criteria may be applied. For 

mobile radars, the fraction of time that the peak interfering signal levels would 

occur is further reduced as a result of the radar mobility. The following criteria 

were established: 

Fixed or transportable radar interfering signals : Ipk/N = 0 dB, 

Maritime or land mobile radar interfering signals: Ipk/N = 10 dB. 

• DMS Employing Forward Error Correction 

 

Several studies have documented measurements demonstrating that 

under certain conditions, a receiver employing FEC will be more immune to pulse 

interfering signals than simple CW or noise-like interfering signals. NTIA 

completed measurements on a digital satellite receiver that would be similar in 

functionality to a DMS.8

 For the single case studied, the digital receiver was 

quite robust in the presence of low duty cycle pulse interfering signals when the 

duty cycle is less than 0.5%. The NTIA report gives guidance as to the degree of 

immunity for various pulse widths and duty cycles but additional study would be 

useful. 

The NTIA study shows that for continuous pulse interfering signals having 

a high duty cycle and/or long pulse characteristic, defined in terms of peak 
4-8

power, resulted in the same degree of degradation as a CW signal. 

4.2.4 Possible Mitigating Factors 

The technical literature describes a number of situations where the criteria 

discussed above may be relaxed as follows: 

• Excess Link Margin 

While designers and operators of FS equipment, as is the case of all radio 

services, aim to achieve the highest possible reliability, in practice each link and 

the overall network as a whole are normally designed to meet specified error 

performance and availability objectives. From a practical standpoint, some links 

in the network may be implemented with excess link margin, higher than 

necessary to achieve these design objectives. For example: 

 A multi-hop microwave network may be designed around the single worst 

link in the network using common equipment (transmitters and antennas) 

for all links. The result is that all but one link in the network may have 

excess link margin. 

 FS transmitters are generally available in only one or two transmitter 

power options. The link designer must, in some cases, use the next 

higher power available, again resulting in possible excess link margin. 

As described in TIA TSB 10-F, if excess fade margin is available, the IPC may be 

relaxed dB for dB.9

Using the C/I methodology and default values for fade margin described in 

TIA TSB 10-F may also allow for relaxed IPC when excess fade margin is 

present.10

• Relaxed Degradation Criteria 

As described above, the baseline ITU-R degradation allowance for coprimary sharing with DMS FS systems is 10%, or the equivalent I/N of –10 dB. 

This criterion has been relaxed to 25%, or the equivalent I/N of –6 dB, under 

certain situations to facilitate sharing, especially in the 1-3 GHz region. 

• Time Sharing 

Most FS systems are operated 100% of the time. Therefore time-sharing 

in the conventional sense is generally not possible. However, microwave fading 

due to multipath (i.e., in bands below about 13 GHz) generally occurs during the 

period midnight to 8:00 am. If a potential interfering system only operates during 
4-9

the 8:00 am to midnight time period, some relaxation of the long-term IPC may 

be possible for DMS operations below 13 GHz.11 

• Short-haul Paths 

The established IPC for the DMS are generally based on long-haul 

performance requirements with many links connected in tandem. However, 

interfering signal levels 1-10 dB or more above these IPC values are usually 

acceptable on shorter or other minimally fading digital paths since long-term 

performance is not adversely affected.12

4.3 FIXED-SATELLITE SERVICE 

4.3.1 General 

This subsection presents IPC for the FSS. The satellite can be in either 

the geostationary orbit (GSO) or non-GSO (NGSO). Because of the advantages 

of digital signal processing, most FSS traffic is digital, or is expected to be digital 

after earth station receiver upgrades. Therefore, only IPC of digital applications 

are presented. 

A telecommunication satellite channel includes an uplink, the satellite, and 

a downlink; noise is included in each portion. The signal quality, in terms of error 

performance requirement, is discussed. The IPC are specified as an 

apportionment of the total noise allowance, while the total noise allowance is 

indirectly specified as the error performance requirement. 

4.3.2 System Characteristics and Performance Objectives 

4.3.2.1 System Characteristics 

As in the case of the FS, FSS system characteristics vary over a wide 

range and cannot be easily characterized. However, Appendix 7 of the ITU-R 

Radio Regulations defines certain receiver technical parameters for use in 

determination of coordination distances between receiving FSS earth stations 

and FS systems. These values, summarized in Table 4-4, may be useful in other 

spectrum sharing studies. 
4-10

Table 4-4 

FSS Default Values in Appendix 7 of ITU-R Radio Regulations 

Interference 

Criteriaiv

Band (GHz)i

Mainbeam 

Antenna 

Gain 

(dBi) 

Minimal 

Elevation 

Angle 

(Deg) 

Equivalent 

Uplink 

Noise, 

Nup

(dB)ii

Noise 

Temperatureiii

(K) 

Fade 

Margin, 

FM 

(dB) 

I

 v

(dBW/

MHz) 

Duration 

(%) 

2.5-2.69 N/S 3 1 75 2 –151 0.003 

3.4-4.2 N/S 3 1 75 2 –151 0.005 

4.5-4.8 N/S 3 1 75 2 –151 0.005 

5.15-5.216 N 48.5 3 1 75 2 –151 N/S 

6.7-7.075 50.7 3 1 75 2 –151 0.005 

7.25-7.75 N/S N/S 1 75 2 –151 0.005 

10.7-12.75 N/S 5 1 150 4 –144 0.003 

10.7-11.7 N 51.9 6 1 150 4 –144 0.003 

12.5-12.75 N 31.2 10 1 150 4 –144 0.003 

15.4-15.7 N 48.4 5 1 150 4 –141 0.003 

17.7-18.8 58.6 5 1 300 6 –138 0.003 

18.8-19.3 N/S N/S 0 300 5 –141 0.003 

19.3-19.7 N 53.2 5 0 300 5 –141 0.01 

19.3-19.7 49.5 10 1 300 6 –138 0.003 

i. Bands indicated with an “N” refer to FSS systems using non-geostationary 

orbits. 

ii. Nup is an approximation for the portion of the noise in an earth station receiver 

due to the uplink and satellite intermodulation noise. 

iii. Noise temperature defined at the input to the receiving antenna terminals. 

iv. These criteria are applicable to only short-term interfering signals. v. I : level of permissible short-term interfering signal power per MHz from all 

sources that may be exceeded for no more than the indicated percentage of 

time (“Duration”). The levels are defined at the input to the antenna terminals. 

This is based on the methodology defined for short-term interfering signals in 

Appendix 7 for Digital FSS as follows: I = receiver noise power density + Nup

+ 10 Log(10FM/10 – 1) .

4.3.2.2 Performance Objectives 

In satellite communications, interference regulation is typically an 

international issue. Thus, FSS frequency coordination procedures, sharing 

criteria, and IPC have been established by the ITU-R in its “S series” of 

Recommendations. A satellite operator, an administration, or an entire ITU-R 

Region may impose more stringent IPC to meet their interference suppression or 
4-11

frequency reuse requirements. 

The signal quality of a digital channel is the bit error ratio (BER) after 

decoding. Different coding schemes yield different BER for the same C/N at the 

input of the demodulator. Since coding schemes are implemented by system 

designers, and can vary even during operation, the total noise allowance can be 

specified only indirectly by the BER requirement. Therefore, in ITU-R 

Recommendations, the digital channel performance requirement is specified in 

terms of an array of BER and availabilities. Each transmission link has its own 

C/N requirement that will enable compliance with the required BER. The IPC are 

determined by budgeting total system noise allowance to the interfering signal 

power, where the total system noise is defined as the noise level giving rise to 

certain BER under clear sky conditions. A summary of these Recommendations 

are listed in Table 4-5 for various digital channels. 

Table 4-5 

List of ITU-R Recommendations Related to IPC 

 ITU-R Recommendations 

Signal 

Error 

Performance 

Objective 

Interfering Signal 

Power 

Apportionment 

Digital connection as part of 

international network at or 

above T1 rate 

S.1062 13, i S.1323 14

S.1429 15, ii

Digital connection as part of 

international Integrated Service 

Digital Network (ISDN) 

S.614 16 S.735 17

Digital Pulse Code Modulation 

(PCM) telephony, non-ISDN S.522 18 S.523 19

Digital Single Channel per 

Carrier (SCPC) interfered with 

by TV/FM 

N/S S.671 20

i. Performance objectives specific to Asynchronous Transfer Mode (ATM) 

transmission are in S.1420.21

ii. For short-term interfering signals occurring between GSO/FSS and 

NGSO/FSS systems. 

4.3.3 Error Performance Objective 

4.3.3.1 Long-term Interfering Signals 

FSS digital signal transmission is generally classified as broadband or 

narrowband. Broadband transmission is defined as data rate of 1.5 Mb/s or 

above (1.5 Mb/s is called T1 rate in the U.S. and primary rate in ITU-R 

documents.) Narrowband transmission can be either ISDN at data rate of 64 
4-12

kb/s, or multiples thereof. 

The end-to-end error performance objective of a broadband international 

connection and the error performance apportionment to a satellite hypothetical 

reference digital path (HRDP) are given in Rec. ITU Telecommunications Sector 

(ITU-T) G.826.22 Based on the G.826 requirements, Rec. ITU-R S.1062 specifies 

the allowable error performance of a FSS satellite HRDP as follows: the 

allowable BER at the output of a HRDP should not exceed the mask given in 

Table 4-6. 

Table 4-6 

FSS Error Performance Objectives 

Bit Rate (Mb/s) % Total Time, 

Worst Month 

BER/α i

0.2 7x10-7

2 3x10-8 1.5 

10 5x10-9

0.2 7x10-6

2 2x10-8 2 

10 2x10-9

0.2 8x10-7

2 1x10-8 6 

10 1x10-9

0.2 4x10-7

2 2x10-9 51 

10 2x10-10

0.2 1x10-7

2 1x10-9 155 

10 1x10-10

i. α: average number of errored bits in a burst of errors. 

The specification applies to systems operating below 30 

GHz. 

 Rec. ITU-T G.826 uses bit-error-probability (BEP) instead of 

BER. 

The end-to-end error performance objective of a 64 kb/s ISDN 

international connection and the error performance apportionment to a satellite 

HRDP are given in Rec. ITU-T G.821.23 Based on the G.821 requirements, Rec. 

ITU-R S.614 specifies the error performance of a 64 kb/s satellite HRDP as 

follows: the BER at the output of a satellite HRDP operating below 15 GHz 

should not exceed: 

• 10-7 for more than 10% of any month, 

• 10-6 for more than 2% of any month, 
4-13

• 10-3 for more than 0.03% of any month. 

The performance requirement for PCM telephony is given in Rec. ITU-R 

S.522 as follows: the allowable BER at the output of the HRDP should not 

exceed: 

• 10-6, 10-minute mean value for more than 20% of any month, 

• 10-4, 1-minute mean value for more than 0.3% of any month, 

• 10-3, 1-second mean value for more than 0.05% of any month. 

4.3.3.2 Short-term Interfering Signals 

Rec. ITU-R S.1323 specifies that interfering signals between FSS 

networks (GSO/FSS, NGSO/FSS, NGSO/MSS feeder link) which are considered 

short-term and time-variant should: 

• be responsible for at most 10% of the time allowance for the BER (or C/N) 

specified in the short-term performance objectives and corresponding to 

the shortest percentage of time (or lowest C/N value), 

• not lead to loss of synchronization for more than once per x days, with the 

value of x for further study. 

Since ITU-R documents consider the interfering signals between 

GSO/FSS and NGSO/FSS systems to be short-term, it is specified in Rec. ITU-R 

S.1429 that 10% of the error performance objective should be allotted to the 

short-term interfering signals between GSO/FSS and NGSO/FSS systems. 

Specifically, the allotment is listed in Table 4-7. 
4-14

Table 4-7 

FSS Error Performance Objectives 

for Short-term Interfering Signals 

Bit Rate (Mb/s) % Total Time, Worst Month BER/α

0.02 7x10-7

0.2 3x10-8 1.5 

1 5x10-9

0.02 7x10-6

0.2 2x10-8 2 

1 2x10-9

0.02 8x10-7

0.2 1x10-8 6 

1 1x10-9

0.02 4x10-7

0.2 2x10-9 51 

1 2x10-10

0.02 1x10-7

0.2 1x10-9 155 

1 1x10-10

Applicable to transmissions below 15 GHz. 

4.3.4 Interference Protection Criteria Summary

ITU-R documents describe a unified interfering signal noise apportionment 

for all digital FSS channels. Rec. ITU-R S.1432 summarizes the IPC from Recs. 

ITU-R S.523, S.671, S.735 and S.1323 as follows:24

For FSS systems operating below 15 GHz, the apportionment of the 

allowable aggregate interfering signal is limited to: 

• 32% of the clear sky satellite system noise for systems not practicing 

frequency reuse; 

• 27% of the clear sky satellite system noise for systems practicing 

frequency reuse. 

The aggregate interfering signal is further partitioned as follows: 

• 25% for other FSS systems for victim system not practicing frequency 

reuse; 

• 20% for other FSS systems for victim system practicing frequency reuse; 

• 6% for other systems having co-primary status; 

• 1% for all other sources. 
4-15

Frequency reuse is a technique to utilize either electromagnetic wave 

polarization isolation or antenna direction isolation (sometimes called coverage 

area spatial isolation) characteristics to reuse the same frequency band multiple 

times on the same satellite network. Almost all FSS systems use polarization 

isolation to use the frequency band twice, and some use direction isolation to 

further reuse the frequency band multiple times. For example, most of the 

INTELSAT satellites utilize both isolation characteristics to use the same 

frequency band 6 times. Frequency reuse generates additional intra-system 

noise. 

Recs. ITU-R S.523, S.671, S.735 and S.1323 specify that the single-entry 

interfering signal power apportionment is 6%. 

Rec. ITU-R S.1323 also specifies that short-term interfering signals 

between the FSS systems should account for only 10% of the error performance 

allotment. Rec. ITU-R S.1429 provides more specific information. 

4.3.4.1 Coordination Trigger 

For a proposed FSS system sharing the same frequency bands with 

existing or other proposed FSS systems, there is a need to determine if 

coordination is required to prevent unacceptable mutual interference. The ITU-R 

provides two methodologies to calculate trigger levels for determining if 

coordination action is required. 

From Rec. ITU-R S.738, the trigger level to determine if coordination 

action is required between two GSO/FSS systems is:25

ΔT/T ≥ 6%, (4-3) 

Where: ΔT = Increase in system noise temperature due to interfering 

 signals, 

 T = receiver noise temperature, 

 k(ΔT)B = I, 

 kTB = N , 

 k = Boltzmann’s constant, 

 B = carrier bandwidth. 

From Rec. ITU-R S.739, a less conservative trigger level to determine if 

coordination action is required between two GSO/FSS systems is the normalized 

ΔT/T value, which modifies the ΔT/T value by taking into account the interferedwith and the interfering carriers.26
4-16

4.3.4.2 IPC for Fixed Satellite Service Broadband Digital Signals 

The IPC for broadband digital signal transmission are given in Rec. ITU-R 

S.1323. The maximum permissible level of interference between GSO/FSS 

satellite networks is considered time-invariant and should not exceed, under 

clear-sky conditions, 

• for aggregate interfering signal power: 

• 25% of total system noise power level for systems not practicing 

frequency reuse; 

• 20% of total system noise power level for systems practicing frequency 

reuse; 

• for single-entry interfering signal power: 6% of total system noise power 

level. 

Here the total system noise power level is defined as the noise power at 

the input of the demodulator, which gives rise to BER of 10-6. The criteria apply 

to transmissions below 30 GHz. 

4.3.4.3 IPC for Fixed Satellite Service Narrowband Digital Signals 

The IPC for ISDN transmission are given in Rec. ITU-R S.735. The 

maximum permissible level of interference from other FSS systems to a 64 kb/s 

GSO/FSS satellite ISDN link should not exceed, under clear-sky conditions, 

• for aggregate interfering signal power: 

 25% of total noise power level for systems not practicing frequency 

reuse; 

 20% of total noise power level for systems practicing frequency reuse; 

• for single-entry interfering signal power: 6% of total noise power level. 

Here the total noise power level is defined as the noise power at the input 

of the demodulator which gives rise to BER of 10-6. The criteria apply to systems 

operating below 15 GHz. 

4.4 SUMMARY 

Tables 4-7 and 4-8 present summaries of IPC for the FS and FSS. 
Table 4-7 

Summary of IPC for FS Digital Channels 

4-17

Systems/ Interference Protection Criteria 

Services 

Frequency 

Bands CW/Noise Pulse/Other 

Reference 

Bandwidth 

% Time Source 

Documen

I/N ≤ –6 dB 

(Other FS 

systems) 

I/N ≤ –10 dB 

(Other primary 

services) 

All FS 

bands 

I/N ≤ –20 dB 

(Non-primary 

sources) 

see rows below 1 MHz 20 (of any month) 

TIA TSB 1

ITU-R F.10

NTIA Rep

02-393 

(I/N)av ≤ –10 dB 

(Other Primary 

Services) 

All FS 

bands 

below 13 

GHz 

(I/N) av ≤ –20 dB 

(Non-primary 

sources) 

see rows below 1 MHz Any Rec. ITU

F.1108 

I/N ≤ NFMi – 5 dB 0.01 

FS (DMS) 

All FS 

bands 

above 17 

GHz I/N ≤ NFM – 1 dB

see rows below 1 MHz 

0.003 

Rec. ITU

F.1495 
Table 4-7 

Summary of IPC for FS Digital Channels (cont) 

4-18

Systems/ Interference Protection Criteria 

Services 

Frequenc

y Bands CW/Noise Pulse/Other 

Reference 

Bandwidth 

% Time Source 

Document(s

All FS 

bands see rows above 

Same criteria 

as noise using 

peak interfering 

signal power 

IF Passband N/S Rec. ITU-R F.1190 

I/N ≤ 0 dB 

(Fixed radar 

source) 

FS (DMS 

without FEC) 

Below 6 

GHz see rows above I/N ≤ 10 dB 

(Mobile radar 

source) 

IF Passband N/S Rec. ITU-R F.1190 

FS (DMS 

with FEC) 

All FS 

bands see rows above See text IF Passband Long- term NTIA Repo

02-393 

i. NFM = Net fade margin taking into account the use of ATPC 
Table 4-8 

Summary of IPC for FSS Digital Channels 

4-19

Systems/ Interference Protection Criteria 

Services 

Frequency 

Bands 

CW/Noise Pulse/Other

Reference 

Bandwidth 

% Time Source 

Document(s

All FSS 

bands 

below 15 

GHz 

Itotal/NBER ≤ –5.7 dB 

 Iagg, FSS/NBER ≤ –7 dB 

Ise, FSS/NBER ≤ –12 dB

Ico-prim/NBER ≤ –12 dB 

Iothers/NBER ≤ –20 dB 

N/S IF Passband 20 (of any month) 

ITU-R S.523 ITU-R S.671 ITU-R S.735 

ITU-R S.132ITU-R S.143

FSS 

All FSS 

bands 

10% of error 

performance 

objective 

N/S IF Passband Short-term ITU-R S.142

Frequency reuse: a satellite reuses the same frequency band multiple times, Itotal total interfering signal power, Iagg, FSS total interfering signal power from other FSS systems, 

Ise, FSS interfering signal power from another FSS system, 

Ico-prim total interfering signal power from services of co-primary status, 

Iothers total interfering signal power from all other sources, 

NBER total clear sky noise power giving rise to the BER objective. 
 

4-20

REFERENCES

1

 Radio Regulations, Appendix 7; Rec. ITU-R F.758, Consideration in the development of criteria 

for sharing between the terrestrial fixed services and other services (2003); Rec ITU-R F.1101, 

Characteristics of digital fixed wireless systems below about 17 GHz (1994); Rec ITU-R F.1102-1, 

Characteristics of fixed wireless systems operating in frequency bands above about 17 GHz

(2002); TIA TSB 10-F, Interference Criteria for Microwave Systems (TIA TSB 10-F), 

Telecommunications Industry Association, Arlington, Virginia (1994). 

2

 Rec. ITU-R F.1189-1, Error performance objectives for constant bit rate digital paths at or above 

the primary rate carried by digital radio-relay systems which may form part or all of the national 

portion of a 27 500 km hypothetical reference path (1997). 

3

 47 CFR §101.105.

4

 Rec. ITU-R F.1094, Maximum allowable error performance and availability degradations to digital 

radio-relay systems arising from interference from emissions and radiations from other sources

(1995). 

5

 Rec. ITU-R F.1108, Determination of the criteria to protect fixed service receivers from the 

emissions of space stations operating in non-geostationary orbits in shared frequency bands

(2000). 

6

 Rec. ITU-R F.1495, Interference criteria to protect the fixed service from time varying aggregate 

interference from other services sharing the 17.7-19.3 GHz band on a co-primary basis (2000). 

7

 Rec. ITU-R F.1190, Protection criteria for digital radio-relay systems to ensure compatibility with 

radar systems in the radiodetermination service (1995). 

8

 NTIA, Report 02-393, Measurements of Pulsed Co-Channel Interference in a 4-GHz Digital Earth 

Station Receiver (2002). 

9

 TIA TSB 10-F, at Sec. 4.2.3. 

10 TIA TSB 10-F, at Sec. 2.5.5 & Appendix B. 

11 TIA TSB 10-F, at Annex F-3.5. 

12 TIA TSB 10-F, at Sec. 2.5.6. 

13 Rec. ITU-R S.1062-2, Allowable error performance for a hypothetical reference digital path 

operating at or above the primary rate (1999). 

14 Rec. ITU-R S.1323-1, Maximum permissible levels of interference in a satellite network 

(GSO/FSS; non-GSO/FSS; non-GSO/MSS feeder links) in the fixed-satellite service caused by 

other codirectional networks below 30 GHz (2003). 
 

4-21

15 Rec. ITU-R S.1429, Error performance objectives due to internetwork interference between GSO 

and non-GSO FSS systems for hypothetical reference digital paths operating at or above the 

primary rate carried by systems using frequencies below 15 GHz (2000). 

16 Rec. ITU-R S.614-3, Allowable error performance for a hypothetical reference digital path in the 

fixed-satellite service operating below 15 GHz when forming part of an international connection in 

an integrated services digital network (1994). 

17 Rec. ITU-R S.735-1, Maximum permissible levels of interference in a geostationary-satellite 

network for an HRDP when forming part of the ISDN in the fixed-satellite service caused by other 

networks of this service below 15 GHz (1995). 

18 Rec. ITU-R S.522-5, Allowable bit error ratios at the output of the hypothetical reference digital 

path for systems in the fixed-satellite service using pulse-code modulation for telephony (1994). 

19 Rec. ITU-R S.523-4, Maximum permissible levels of interference in a geostationary-satellite 

network in the fixed-satellite service using 8-bit PCM encoded telephony, caused by other 

networks of this service, (1992). 

20 Rec. ITU-R S.671-3, Necessary protection ratios for narrow-band single channel-per-carrier 

transmissions interfered with by analogue television carriers (1994). 

21 Rec. ITU-R S.1420, Performance for broadband integrated services digital network 

asynchronous transfer mode via satellite (1999). 

22 Rec. ITU-T G.826, (End-to-end error performance parameters and objectives for international, 

constant bit-rate digital paths and connections (2002). 

23 Rec. ITU-T G.821, Error performance of an international digital connection operating at a bit rate 

below the primary rate and forming part of an Integrated Services Digital Network (2002). 

24 Rec. ITU-R S.1432, Apportionment of the allowable error performance degradations to fixed 

satellite service (FSS) hypothetical reference digital paths arising from time invariant interference 

for systems operating below 15 GHz (2000). 

25 Rec. ITU-R S.738, Procedure for determining if coordination is required between geostationarysatellite networks sharing the same frequency bands (1992). 

26 Rec. ITU-R SF.739, Additional methods for determining if detailed coordination is necessary 

between geostationary-satellite networks in the fixed-satellite service sharing the same frequency 

bands, (1992). 
 

4-22

This page intentionally blank. 
 

5-1

SECTION 5 

RADIODETERMINATION AND RADIODETERMINATION-SATELLITE 

SERVICES 

5.1 INTRODUCTION 

Various types of systems operate in the radiodetermination and 

radiodetermination-satellite services from 30 MHz to 30 GHz. These systems 

perform a variety of functions in the United States, including monitoring weather 

phenomena, surveillance of the national airspace and waterways, and providing 

navigation safety-of-life services. 

The radiodetermination service includes radiolocation, aeronautical 

radionavigation and maritime radionavigation services. With the exception of 

aeronautical and maritime radionavigation systems that use transponders or transmit 

information to and from ground stations, these systems rely on passively reflected or 

scattered radar signal returns to detect and/or track point targets (e.g., planes, 

ships,). Meteorological aids (weather radars) are also included here because of 

certain commonalties they have with radars that are operated in the 

radiodetermination service (i.e., pulse width, pulse rate, and type of transmitter 

output device). However, weather radars are designed to detect/monitor distributed 

targets such as clouds, rain, hail, and other weather phenomena. Radar altimeters 

are unique in that they radiate towards the earth so that aircraft can determine their 

height above ground. 

The form of the IPC for radiodetermination systems that rely on reflected 

returns is I/N. For aeronautical radionavigation systems that employ a data-link 

between ground stations and aircraft, the IPC are in the form of S/I, an absolute 

interfering signal power limit, or other form. 

5.2 RADIODETERMINATION SERVICE 

5.2.1 Radars operated in the Radiolocation, Aeronautical Radionavigation, 

Meteorological Aids, and Maritime Radionavigation Services 

The technical characteristics and IPC for systems operating in the 

radiolocation and radionavigation services are contained in Part 4 of the M series of 

the ITU-R Recommendations. Rec. ITU-R. M.1461 contains the general IPC for 

these systems if no other IPC are identified in a Recommendation that addresses a 

particular frequency band.1

 Rec. ITU-R M.1461 also contains guidance on the 

methodology for analysis of potential interfering signals between radars and systems 

operating in other services. Table 5-1 lists the relevant ITU-R Recommendations 

that are in effect and the preliminary and draft new Recommendations (DNR). 
 

5-2

Table 5-1 

List of Relevant ITU-R Recommendations 

for Radiodetermination Service 

Frequency Band And 

Service 

IPC for CW and 

Noise-like 

Interfering Signals 

ITU-R Recommendation

420-450 MHz Radiolocation I/N ≤ –6 dB M. 14622

1215-1400 MHz 

Radiodetermination I/N ≤ –6 dB M. 14633

2700-2900 MHz 

Radionavigation and 

Meteorological Aids 

I/N ≤ –10 dB M. 14644 

2900-3100 MHz Maritime 

Radionavigation I/N ≤ –6 dB M. 13135 

2900-3100 MHz 

Radiodetermination and 

Meteorological Aids 

I/N ≤ –6 dB M. 14606

3100-3700 MHz 

Radiodetermination I/N ≤ –6 dB M. 14657

5250-5850 MHz 

Radiolocation, Aeronautical 

Radionavigation, and 

Meteorological Aids 

I/N ≤ –6 dB M. 16388 

8500-10500 MHz 

Radiodetermination I/N ≤ –6 dB Preliminary DNR (Doc.# 8B/282) 

13.75-14 GHz Radiolocation 

and Radionavigation I/N ≤ –6dB M. 16449 

31.8-33.4 GHz 

Radionavigation I/N ≤ –6 dB M. 146610

33.4-36 GHz 

Radiodetermination I/N ≤ –6 dB M. 164011 

All except as noted I/N ≤ –6 dB M. 1461 

5.2.2 CW and Noise-like Interfering Signals 

The baseline ITU-R IPC for interfering signals that appear CW or noise-like in 

the radar receiver are an I/N of –6 dB for single entry and aggregate interfering 

signals if multiple interferers are present. The I/N is calculated within the 3 dB IF 

bandwidth of the victim receiver. The IPC represents a 1 dB increase in the effective 

noise power of the radar receiver. These IPC do not apply to interfering signals that 

appear pulse-like in the radar receiver. The I/N of -6 dB applies 100% of the time, 

and so, it is applied for both long-term and short-term interfering signals. In the ITU, 

Work Party 8B has developed a work program to address the feasibility of 

determining IPC based on statistical methods. 
 

5-3

The IPC in the ITU-R Recommendations are not referenced to particular 

radar performance standards such as a decrease in the target probability of 

detection or an increase in the number of false targets. However, the performance 

degradation can be determined once the specific system characteristics are known 

along with the IPC. For maritime radars, the International Maritime Organization 

(IMO) specifies that radars operating on a vessel must be able to detect a target of 

10 square meters at a distance of 2 nautical miles.12 A European standard exists for 

the performance of aeronautical surveillance radars that specifies the minimum 

probability of target detection is 0.90.13

NTIA, with assistance from the Federal Aviation Administration (FAA), 

National Weather Service (NWS) and the United States Coast Guard (USCG), 

performed tests with maritime radars in the 2900-3100 MHz band and with 

aeronautical radionavigation radars and meteorological aids in the 2700-2900 MHz 

band to determine if the current ITU-R I/N IPC are stringent enough to protect their 

operations. The results of these tests were submitted to the ITU as contributions to 

Working Party 8B (WP8B) as United States contributions (WP8B Documents 8B/275 

and 8B/272 (available from NTIA)). Eurocontrol also submitted a similar contribution 

to WP8B concerning the aeronautical radionavigation radars (WP8 B Documents 

8B/137, 8B/137, 8B/139 (available from NTIA)). Generally, the results of the tests 

show that the current I/N IPC of –6 dB is not sufficient to protect radar operations in 

those bands and that the IPC should be no higher than an I/N of –10 dB. The ITU 

Radiocommunication Assembly has reviewed the contributions and the protection 

criteria in Rec. ITU-R M.1464 has been changed to an I/N of –10 dB. 

5.2.3 Pulse-Like Interfering Signals 

IPC for radiolocation and radionavigation receivers for pulse-like interfering 

signals have not been specifically addressed by the ITU in the M series of 

Recommendations. However, test results submitted to the ITU by NTIA have shown 

that radars that contain Interference Rejection (IR) circuitry and/or software can 

operate in the presence of other similar low duty cycle (< 2%) radars with I/N up to 

60 dB without detrimental effect (WP8B documents 8B/207 and 8B/124 (available 

from NTIA)). These results have been published by the ITU as a Report.14 Rec. 

ITU-R M.1372 contains methods for radars to operate in a more efficient manner 

with other radars.15 This includes descriptions of typical interference rejection 

mechanisms that are capable of limiting the effects of pulsed interfering signals in 

radars. 

5.2.4 Impulse-Like Interfering Signals 

Neither the ITU, ICAO, RTCA, RTCM, nor the IEC have published any 

recommendations concerning IPC for impulse-like, ultrawideband (UWB) interfering 

signals. However, ITU Task Group 1/8 has been formed by the ITU to address the 

issue of UWB signal characteristics and protection criteria. The ITU has directed 
 

5-4

that any compatibility studies between UWB devices and systems in other services 

must be submitted through Task Group 1/8. 

In NTIA Special Publication 01-43, NTIA performed compatibility analyses 

between federal government systems and UWB devices for the FCC UWB rulemaking.16 NTIA chose to use the existing and proposed ITU thresholds for the 

radiodetermination receiver protection criteria which was an I/N of –6 dB or –10 dB, 

as per Table 5-6.17

The I/N values were based on the average interfering signal power within the 

IF passband calculated with the RMS voltage. After the UWB Rulemaking was 

completed, NTIA, USCG, and the British Coast Guard performed interference 

susceptibility tests on maritime radionavigation radars that operate in the 2900-3100 

and 9200-9500 MHz bands with UWB devices. The full results of those tests have 

been submitted to the ITU and were used for modifying the Recommendations. 

Generally, the test results show that marine radars in these bands require an I/N of –

10 to –6 dB based on average power of the UWB transmitter. 

5.2.5 Aeronautical Radionavigation Systems (other than radars using passive 

reflections) 

The IPCs for aeronautical radionavigation systems using transponders or 

beacons are in the form of S/I, S/(N+I), an absolute interfering signal power limit in 

dBm, or I/N. The IPCs for some of these systems are published by the ITU, FAA, 

RTCA, and ICAO. These systems include the Instrument Landing System (ILS) 

localizer and VOR, Distance Measuring Equipment (DME), Air Traffic Control Radio 

Beacon (ATCRBS), and the Microwave Landing System (MLS). IPCs for these 

systems are shown in Table 5-2. 

The FAA has developed procedures for coordinating the use and positioning 

of VOR, DME, TACAN, and ILS localizer systems in FAA publication 6050.32.18 The 

material contained in the document is intended to be used by FAA personnel for 

determining frequency and/or distance separations for these types of systems. The 

IPCs for these systems, when considering interfering signals from another system of 

the same type, are in the form of a desired-to-understand signal power ratio (D/U). 

These D/U-s are based on an availability of 95 percent. The D/U-s are specified for 

different frequency separations. The D/U is the greatest when the systems are cochannel and is lessened as the frequency separation increases. 
 

5-5

Table 5-2 

Aeronautical Radionavigation Protection Criteria 

System Frequency Band IPC 

ILS 

Localizer 108-112 MHz 

Signal Dependent, see 

ITU-R SM.1009-1,19

ITU-R SM.114020 

ILS 

VOR 108-117.95 MHz 

Signal Dependent, see 

ITU-R SM.1009-1, 

ITU-R SM.1140 

ILS 

Marker Beacon 74.8-75.2 MHz I/N ≤ 0 dB21

ILS 

Glide Slope 328.6-335.4 MHz N/S 

DME 962-1213 MHz I ≤ –99 dBm22

MLS 5030-5091 MHz I ≤ –134 dBm23

Radar Altimeters 4200-4400 MHz 

S/(N+I) ≥12 dB for FM-CW type 

altimeters, 

S/(N+I) ≥ 6 dB for Pulsed type 

altimeters 

ATCRBS 1030 and 1090 MHz S/I ≥ 12 dB for Interrogator24 

S/I ≥12 dB for Transponder25

The IPC in Table 5-2 are for a continuous type of signal and are not 

apportioned for interference allotment to other services. They are not defined in 

terms of short- and long-term criteria. The references for each system in Table 5-2 

further define the exact nature of the interfering signals. 

5.3 RADIONAVIGATION-SATELLITE SERVICE 

The primary systems operating in the radionavigation satellite service (RNSS) 

are GPS, launched and maintained by the United States, and GLONASS, launched 

and maintained by the Russian Federation. In addition there are space-based 

augmentation systems (SBAS) and ground-based augmentation systems (GBAS) 

operating in the RNSS frequency bands.a

 These augmentation systems provide 

additional information that enhances the integrity, accuracy, continuity, and reliability 

 

a

 In the United States the SBAS is the Wide Area Augmentation System (WAAS) and the GBAS is 

the Local Area Augmentation System (LAAS). These augmentation systems are capable of 

supporting both GPS and GLONASS signal formats. 
 

5-6

of the RNSS systems. The GPS and GLONASS RNSS systems allow users 

equipped with appropriate receivers to determine position, velocity, and time (PVT) 

information free of charge. 

GPS is a Code Division Multiple Access (CDMA) based system. That is, 

each satellite broadcasts ranging signals with different coding sequences to allow 

the receiver to access the individual satellite signals. GLONASS is a Frequency 

Division Multiple Access (FDMA) based system. That is, each satellite that is visible 

to a user receiver broadcasts ranging signals on different frequencies to allow 

access to individual satellite signals. The various ranging signals are coded at clock 

rates from 1.023 MHz up to 10.23 MHz. 

The frequency bands allocated internationally to the RNSS are 1164-1215 

MHz, 1215-1350 MHz, 1559-1610 MHz, and 5000-5030 MHz. GPS provides a 

ranging signal centered at 1227.6 MHz (L2) and two ranging signals centered at 

1575.42 MHz (L1). In the future, GPS is to add ranging signals at 1176.45 MHz (L5) 

and 1227.6 MHz for civil use. Additional ranging signals will also be added at L1 for 

military use. GLONASS provides ranging signals in the 1559-1610 MHz and 1215-

1350 MHz RNSS bands. 

The European Union is also developing a RNSS system referred to as Galileo 

that will provide ranging signals in the three frequency bands allocated for RNSS. 

Galileo will use CDMA and will provide ranging signals for both public and restricted 

use. The operators of this system will charge some kind of user fee or excise tax for 

the service. 

5.3.1 IPC Values for GPS Receivers 

GPS receivers are used in a myriad of applications including navigation 

(aviation, space, maritime, rail, and vehicular), position determination (surveying, 

asset tracking, enhanced-911), and timing (banking, power distribution, Internet 

synchronization). The IPC values for GPS receivers will depend on: 1) the receiver 

application; 2) the category of interfering signal (noise-like, CW, or pulse-like); 3) 

receiver architecture (coarse/acquisition (C/A), semi-codeless, narrow correlator C/A 

code); and 4) performance criteria (break-lock, reacquisition, pseudorange error). 

Since the IPC for GPS receivers are better organized by the type of 

application rather than the type of interfering signal, the IPC are presented below for 

Aviation, Maritime, Land-based, and Space-based uses of RNSS. 

5.3.1.1 Aviation Applications 

The ITU-R and the RTCA are the primary sources of published IPC values for 

GPS receivers used in aeronautical applications. General receiver characteristics 

and IPC values are contained in Rec. ITU-R M.1477 for aeronautical and ground-
 

5-7

based receivers. 26 The RTCA has also published IPC values for GPS receivers that 

are used for aviation applications in RTCA DO-229B. 27 

The GPS IPC in Rec. ITU-R M.1477 are based on a minimum desired signal 

and are specified for the signal tracking and signal acquisition modes of a GPS 

receiver. The IPC are applicable to GPS receivers used for airborne navigation (enroute and Category I precision approach)b

 and GPS receivers used in a groundbased network (WAAS reference stations). The airborne receivers are intended for 

use with the C/A code signal at 1575.42 MHz. The ground-based network receiver 

employs the semi-codeless architecture that processes both the C/A code and 

Precision code (P-code) signals at 1575.42 MHz and the P-code signal at 1227.6 

MHz. The P-code signals are cross-correlated (does not require knowledge of the 

coding sequence) to provide a measure of the ionospheric delay to improve the 

accuracy of the range determination. The cross-correlation is made possible by the 

fact that the two P-code signals from a given satellite have identical, synchronized 

code sequences. For each of the receivers addressed in Rec. ITU-R M.1477, IPC 

are specified for narrowband (CW) and wideband (noise-like) interfering signals. In 

this context, narrowband is defined as a bandwidth of less than 700 Hz, and 

wideband is defined as a bandwidth of between 100 kHz to 1 MHz. 

The GPS IPC presented in Rec. ITU-R M.1477 are specified in terms of 

interfering signal power threshold and are summarized in Table 5-3. These IPC are 

referenced to the input of the GPS receiver and are based on a minimum available 

GPS C/A code signal level of –134.5 dBm (–130 dBm minimum guaranteed signal 

level into a –4.5 dBic antenna). The associated performance criteria for GPS 

aeronautical receivers are in the form of pseudorange error. 

The ITU-R is the primary source of published IPC values for GLONASS 

receivers used in aeronautical applications. General receiver characteristics and 

IPC are contained in Rec. ITU-R M.1477 for aeronautical receivers. Rec. ITU-R 

M.1477 specifies IPC applicable to four types of GLONASS aeronautical receivers. 

These receivers are used for en-route navigation and Category I approaches, SBAS, 

and Category I/II/III approaches. The GLONASS IPC values in Rec. ITU-R M.1477 

are contained in Table 5-4. 

 

b

 Category I, II, and III approaches are required for different landing visibility conditions in terms of 

vertical visibility ceiling and runway visual ranges; the visibility decreasing with increasing category 

numbers. 
 

5-8

Table 5-3 

ITU-R Aeronautical GPS Receiver IPC Values for Wideband 

 and Narrowband Interfering Signals 

Receiver Application and Mode Interfering Signal Power Threshold 

Narrowband Signal Wideband Signal 

Airborne Navigation 

Tracking Mode –150.5 dBW –140.5 dBW/MHz 

Acquisition Mode –156.5 dBW –146.5 dBW/MHz 

Ground-Based Network 

Tracking Mode –154.5 dBW –146.5 dBW/MHz 

Acquisition Mode –156.5 dBW –146.5 dBW/MHz 

Note: The IPC values in this table are in terms of the highest aggregate interfering 

signal power at the receiver input at which the receiver is to operate without 

unacceptable performance degradation. 

Table 5-4 

ITU-R Aeronautical GLONASS Receiver IPC Values for Wideband 

and Narrowband Interfering Signals 

Receiver Mode Interfering Signal Power Threshold 

Narrowband Signal Wideband Signal 

Tracking Mode –149 dBW –146 dBW/MHz 

Acquisition Mode –155 dBW –152 dBW/MHz 

Note: The IPC values in this table already take into account the effects of GLONASS 

intra-system interference based on analysis of random codes. The IPC values must 

account for the aggregate of all other interfering signals. 

The RTCA IPC thresholds are meant to be applied to only aviation GPS 

receivers. RTCA has developed IPC for initial satellite acquisition, satellite 

reacquisition, and steady state conditions. They are shown below in Table 5-5, and 

apply to broadband noise-like interfering signal sources centered at the L1 frequency 

of 1575.42 MHz. The test procedures for the RTCA IPC are quite extensive and 

detailed. RTCA DO-229B should be thoroughly reviewed before application of these 

IPC. The IPC values specified by RTCA are referenced to the input of the GPS 

receiver and are based on a minimum available GPS C/A code signal level of –134.5 

dBm (–130 dBm minimum guaranteed signal level into a –4.5 dBic antenna). 

RTCA has published IPC for CW-like signals for aviation GPS receivers in 

DO-229B that are shown below in Table 5-6. They only apply to receiver steady 

state conditions. 
 

5-9

Table 5-5 

Noise-like IPC values for Aviation GPS Receivers 

Initial Satellite Acquisition i

Noise Bandwidth Total Power Threshold 

100 kHz 

20 MHz 

I ≤ –116.5 dBm 

I ≤ –103.5 dBm 

 i Single Trial Pass criteria: The sensor provides a valid position fix within 5 

minutes and maintains an accuracy of 15 meters for 95 percent of the time 

for the next 60 seconds. 

Satellite Reacquisitionii

Noise Bandwidth Total Power Threshold 

100 kHz 

20 MHz 

I ≤ –110.5 dBm 

I ≤ –97.5 dBm 

ii Single Trial Pass criteria: The sensor includes the reacquired satellite into 

the position solution within 10 seconds and maintains an accuracy of 15 

meters for 95 percent of the time for the next 60 seconds. 

Steady State Accuracy IPCiii

Noise Bandwidth Total Power Threshold 

100 kHz 

20 MHz 

I ≤ –110.5 dBm 

I ≤ –97.5 dBm 

iii The pass/fail criteria are based on the normalized RMS range error statistic 

of the satellite pseudorange. 

Table 5-6 

CW IPC Values for Aviation GPS Receivers 

Frequency (MHz) Interfering Signal Power 

Threshold (dBm) 

Corresponding I/S (dB) 

1525.0 –12.0 122.5 

1555.42 –89.5 45.0 

1575.42 –120.5 14.0 

1595.42 –89.5 45.0 

1610.0 –30.0 104.5 

1618.0 –12.0 122.5 

1626.0 +8.0 142.5 

The pass/fail criteria are based on the normalized RMS range error statistic 

of the satellite pseudorange. 

RTCA has published IPC in DO-229B for pulse-like signals for aviation GPS 

receivers that are summarized in Table 5-7. These IPC apply only to steady state 

conditions. These IPC are specified as a function of interfering pulse width, duty 

cycle, and carrier power. 
 

5-10

Table 5-7 

Pulsed Interfering Signal IPC for Aviation GPS Receivers 

Frequency 

(MHz) 

GPS only Interfering Signal 

Pulse Width 

GPS and WAAS 

Interfering Signal Pulse 

1575.42 

Pulse 

width 

1 

millisecond

I ≤ 20 

dBm 

Duty 

Cycle 

10 % 

Pulse 

Width 

125 

μS 

I ≤ 20 

dBm 

Duty 

Cycle 

10 % 

The pass/fail criteria are based on the normalized RMS range error statistic 

of the satellite pseudorange. 

5.3.1.2 Maritime Applications 

Maritime GPS receivers are used for navigation in constricted waterways, 

harbor navigation, docking operations, navigation around bridges, lock operations. 

IEC has adopted a maximum permissible interference level based on the levels 

developed by RTCA for aviation receivers.28 The IPC are specified for a GPS L1 

narrow correlator C/A code receiver. For in-band broadband noise-like interfering 

signals, the IEC has specified that the interfering signal power density should not 

exceed –140 dBW/MHz in a GPS maritime receiver operating in the tracking mode.

5.3.1.3 Space Based Applications 

GPS and GLONASS receivers are used for navigation of spacecraft (real-time 

and post-processed), spacecraft attitude determination, orbit determination, time 

synchronization, launch vehicle range safety, and launch vehicle guidance. GPS 

receivers for space-based applications use the C/A code signal at 1575.42 MHz and 

the P-code at 1227.6 MHz. IPC for space-based GPS and GLONASS receivers are 

provided in Rec. ITU-R M.1479.29

The GPS IPC for aggregate interfering signal power spectral density at the 

antenna output from Rec. ITU-R M.1479 are: –135 dBW/MHz for wideband 

interfering signals and –135 dBW/100 kHz for narrowband interfering signals. These 

IPC were derived from the 34 dB(Hz) carrier-to-noise density threshold for L1 C/A 

code acquisition and assume certain desired GPS signal power levels and GPS cochannel interfering signal levels experienced by receivers in low-earth orbit (receiver 

< 2000 km altitude). 

The front-end of a GPS receiver is affected by interfering signals in two ways. 

The first mechanism affects the high-level limiter diode in the RF front-end. The 

diode will saturate and prevent burnout of the following receiver stages. Rec. ITU-R 

M.1479 specifies a preamplifier limiting level of –70 dBW, which causes a temporary 

loss of signal. If the average RF power at the receiver input exceeds 0 dBW or peak 

RF power exceeds 10 dBW, the high-level limiter diode may fail because of burnout. 
 

5-11

In Rec. ITU-R M.1479, the in-band wideband interfering signal power density 

at the receiving antenna output of a GLONASS space-based receiver should not 

exceed –140 dBW/MHz. 

 

5.4 Summary 

Table 5-10 presents a summary of IPC for the radiodetermination services. 
Table 5-10 

 Summary of IPC for Radiodetermination Services 

5-12

Systems Interference Protection Services 

Frequency 

Bands CW/Noise Pulse 

Other

Reference 

bandwidth 

% 

Time 

Source Document

Aeronautical 

Radionavigation 

(ILS Beacon) 

74.8-75.2 

MHz I/N ≤ 0 dB N/S System IF Bandwidth N/S RTCA DO-143, NTIA Tech Report 

Radiolocation 420-450 MHz I/N ≤ –6 dB N/S System IF Bandwidth N/S Rec. ITU-R M.1462 

Aeronautical 

Radionavigation 

(DME) 

962-1213 

MHz I ≤ –99 dBm N/S System IF Bandwidth N/S RTCA DO-189, NTIA RPT 01-143 

Aeronautical 

radionavigation 

(ATCRBS) 

1030 and 

1090 MHz S/I ≤ 12 dB N/S System IF Bandwidth N/S RTCA DO-181A, FAA-E-2716 

Radiodetermination All unless otherwise noted I/N ≤ –6 dB N/S System IF Bandwidth N/S Rec. ITU-R M.146Radiodetermination 1215-1400 MHz I/N ≤ –6 dB N/S System IF Bandwidth N/S Rec. ITU-R M.1463 

Radionavigation 

and 

Meteorological 

2700-2900 

MHz I/N ≤ –10 dB N/S System IF Bandwidth N/S Rec. ITU-R M.1464 

Maritime 

Radionavigation 

2900-3100 

MHz I/N ≤ –6 dB N/S System IF Bandwidth N/S Rec. ITU-R M.1313

NTIA RPT 01-143 

Radiodetermination and 

Meteorological 

2900-3100 

MHz I/N ≤ –6 dB N/S System IF Bandwidth N/S Rec. ITU-R M.1460 

Radiodetermination 3100-3700 MHz I/N ≤ –6 dB N/S System IF Bandwidth N/S Rec. ITU-R M.1465 
Table 5-10 

 Summary of IPC for Radiodetermination Services 

5-13

Systems Interference Protection Services 

Frequency 

Bands CW/Noise Pulse 

Other

Reference 

bandwidth 

% 

Time 

Source Document

Radar Altimeters 4200-4400 MHz 

S/(N+I) ≥ 12 dB 

CW Systems, 

S/(N+I) ≥ 6 dB 

Pulsed Systems

N/S System IF Bandwidth N/S Manufacturers Brochures 

Aeronautical 

Radionavigation 

(MLS) 

5030-5091 

MHz I ≤ –134 dBm N/S 26 kHz N/S 

ICAO 

Radionavigation 

Aids Annex 10 Vol

1, 

NTIA RPT 01-143 

Radiolocation, 

Aeronautical 

Radionavigation, 

and 

Meteorological 

5280-5850 

MHz I/N ≤ –6 dB N/S System IF Bandwidth N/S Rec. ITU-R M.1638 

Radiodetermination 8500-10500 MHz I/N ≤ –6 dB N/S System IF Bandwidth N/S REC. ITU-R M.XXX 

Radionavigation 

and 

Radionavigation 

13.75-14 

GHz I/N ≤ –6 dB N/S System IF Bandwidth N/S Rec. ITU-R M.1644 

Radionavigation 31.8-34.4 GHz I/N ≤ –6 dB N/S System IF Bandwidth N/S Rec. ITU-R M.1466 

Radiodetermination 33.4-36 GHz I/N ≤ –6 dB N/S System IF Bandwidth N/S Rec. ITU-R M.1640 
5-14

REFERENCES

1

 Rec. ITU-R M. 1461, Procedures for Determining the Potential for Interference 

Between Radars Operating in the Radiodetermination Service and Systems in Other 

Services (2003). 

2

 Rec. ITU-R M. 1462, Characteristics of and Protection Criteria for radars operating 

in the Radiolocation Service in the Frequency Range 420-450 MHz (2000). 

3

 Rec. ITU-R M. 1463, Characteristics of and Protection Criteria for Radars 

Operating in the Radiodetermination Service in the Frequency Band 1215-1400 MHz

(2000).

4

 Rec. ITU-R M. 1464, Characteristics of and Protection Criteria for Radionavigation 

and Meteorological Radars Operating in the Band 2700-2900 MHz (2003). 

5

 Rec. ITU-R M. 1313, Technical and Operational Characteristics and Protection 

Criteria of Maritime Radionavigation Radars in the Band 2900-3100 MHz (2000) 

6

 Rec. ITU-R M. 1460, Technical and Operational Characteristics and Protection 

Criteria of Radiodetermination and Meteorological Radars in the 2900-3100 MHz 

band (2000). 

7

 Rec. ITU-R M. 1465, Characteristics of, and Protection Criteria for Radars 

Operating in the Radiodetermination Service in the Frequency Band 3100-3700 MHz

(2000). 

8

 Rec. ITU-R M. 1638, Characteristics of and protection criteria for sharing studies 

for radiolocation, aeronautical radionavigation and meteorological radars operating 

in the frequency bands between 5250 and 5850 MHz (2003). 

9

 Rec. ITU-R M. 1644, Technical and operational characteristics, and criteria for 

protecting the mission of radars in the radiolocation and radionavigation service 

operating in the frequency band 13.75-14 GHz (2003). 

10 Rec. ITU-R M. 1466, Technical and Operational Characteristics of Radars 

Operating in the Radionavigation Service in the Frequency Band 31.8-33.4 GHz

(2003). 

11 Rec. ITU-R M. 1640, Characteristics of, and protection criteria for sharing studies 

for radars operating in the radiodetermination service in the frequency band 33.4-36 

GHz (2003). 

12 Regulation 12, Chapter V of the International Convention for the Safety of Life at 

Sea (SOLAS), as amended (1974). 
5-15

13 SUR.ET1.ST01.1000-STD-01-01, Standard Document for Radar Surveillance in 

en-Route Airspace and Major Terminal Areas, Eurocontrol (March 1997). 

14 Report ITU-R M.2032, Tests illustrating the Compatibility between Maritime 

Radionavigation radars and Emissions from radiolocation Radars in the Band 2900-

3100 MHz (2002).

15 Rec. ITU-R M. 1372-2, Efficient Use of the Radio Spectrum by Radar Stations in 

the Radiodetermination Service (2003). 

16Revision of Part 15 of Commission’s Rules Regarding Ultra-Wide-Band 

Transmissions Systems, First Report and Order, ET Docket No. 98-153, 17 F.C.C. 

Rcd. 7435 (2002) 

17 NTIA Special Publication 01-43, Assessment of Compatibility Between 

Ultrawideband Devices and Selected Federal Systems, (2001). 

18 FAA 6050.32A, Spectrum Management Regulations and Procedures Manual, 

Federal Aviation Administration (May 1998). 

19 Rec. ITU-R SM. 1009-1, Compatibility between the Sound-Broadcasting Service in 

the Band 87-108 MHz and the Aeronautical Services in the Band 108-137 MHz

(1995). 

20 Rec. ITU-R SM. 1140, Test Procedures for Measuring Aeronautical Receiver 

Characteristics used for Determining Compatibility Between the Sound-Broadcasting 

Service in the Band of about 87-108 MHz and the Aeronautical Services in the Band 

108-118 MHz (1995). 

21 RTCA/DO-143, Minimum Operational Performance Standards Airborne Radio 

Marker Beacon Receiving Equipment Operating on 75 MHz, RTCA, at 5 (1970). 

22 RTCA DO-189, Minimum Operational Performance Standards for Airborne 

Distance Measuring Equipment (DME) Operating within the Radio Frequency Range 

of 960-1215 MHz, RTCA (1985). 

23 International Standards and Recommended Practices Annex 10 to the Convention 

on International Civil Aviation, Volume 1 (Radio Navigation Aids) Fifth Edition (1996). 

24 FAA-E-2716, Specification for Mode Select Beacon System (Mode S) Sensor, 

Federal Aviation Administration, Amendment 2 (1983). 

25 RTCA/DO-181A, Minimum Operational Performance Standards for Air Traffic 

Control Radar Beacon System/ Mode Select (ATCRBS/Mode S) Airborne 

Equipment, RTCA (January 1992). 
5-16

26 Rec. ITU-R M. 1477, Technical and Performance Characteristics of Current and 

Planned Radionavigation-Satellite Service (Space-to-Earth) and Aeronautical 

Radionavigation Service Receivers to be considered in Interference Studies in the 

Band 1559-1610 MHz (2000). 

27 RTCA/DO-229B, Minimum Operational Performance Standard for GPS/Wide area 

Augmentation System Airborne Equipment, RTCA (January 1996). 

28 IEC 61108-1, Global Navigation Satellite System (GNSS), Part 1: Global 

Positioning System (GPS) Receiver Equipment Performance Standard, Methods of 

Testing and Required Results, International Electrotechnical Commission (July 

2003). 

29 Rec. ITU-R M.1479, Technical Characteristics and Performance Requirements of 

Current and Planned Radionavigation-Satellite Service (Space-to-Space) Receivers 

to be Considered in Interference Studies in the Frequency Bands 1215-1260 MHz 

and 1559-1610 MHz (2000).
6-1

SECTION 6 

BROADCASTING AND BROADCASTING-SATELLITE SERVICES 

6.1 INTRODUCTION 

This section describes the IPC from various sources for the broadcasting service 

(BS) and broadcasting-satellite service (BSS). Although there are several frequency 

bands below 30 MHz allocated to terrestrial broadcasting for federal use, none are 

allocated for use by the federal government above 30 MHz for either terrestrial or 

satellite broadcasting. The IPC are provided herein to facilitate sharing feasibility 

studies with non-federal BS or BSS receivers. With few exceptions, available IPC 

values for the BS and BSS are limited to consideration of interfering signals from within 

the same radio service. The IPC for the BS and BSS are generally specified in terms of 

C/I values. 

6.2 BROADCASTING SERVICE 

The BS consists of radio or television broadcasting from terrestrial stations for 

direct reception by the general public.a

 The BS is presently limited to the frequency 

bands between 30 MHz and 30 GHz shown in Table 6-1.b

Table 6-1 

U.S. BS Allocations between 30 MHz and 30 GHz 

Bands (MHz) Service 

54-72 TV (channels 2-4) 

76-88 TV (channels 5-6) 

88-108 FM radio (channels 201-300) 

174-216 TV (channels 7-13) 

470-608 TV (channels 14-36) 

614-746 TV (channels 38-59) 

746-806 TV (channels 60-69)c

This table shows all of the BS allocations in the United States within the defined 

frequency range, which are discussed in the following subsections. 

 

a In addition to broadcasting, other types of transmissions are permissible including various data services 

under FCC regulations. 

b All bands are exclusively for non-federal use. 

c Television channels 60 through 69 are to be reallocated for commercial LMR and public safety use after 

the digital television transition date, which is no earlier than December 31, 2006. 
 6-2

6.2.1 Broadcast Television 

Spectrum allocated for broadcast television is divided into 6 MHz channels 

ranging from television channels 2 through 69. Conventional analog transmissions will 

be replaced by digital television (DTV) over time. Under the transition plan, 

broadcasters are assigned a locally vacant channel for DTV while temporarily keeping 

their current analog channel. 

The IPC for television are contained primarily in ITU-R Recommendations and 

FCC Rules (Title 47 CFR, Part 73). In the ITU-R Recommendations, the IPC are listed 

for 3 different digital television standards: ATSC (Advanced Television Systems 

Committee), DVB-T (Digital Video Broadcasting-Terrestrial), and ISDB-T (Integrated 

Service Digital Broadcasting-Terrestrial). DVB-T was adopted by Europe, Africa, 

Australia, and Greenland. ISDB-T was adopted by Japan. ATSC was adopted by the 

United States and Canada, thus, this report will focus on ATSC IPC. Analog TV 

resolutions of 525 and 625 lines are addressed in the ITU, but this report will address 

only the 525 line M/NTSC analog standard used within the United States. 

IPC for DTV have been developed for continuous and tropospheric interfering 

signals. Continuous interfering signals are defined as long-term interfering signals that 

are exceeded for 50% or more of the time and generally serve as the baseline for 

establishing protection criteria. Tropospheric interfering signals are defined as shortterm interfering signals that are exceeded for no more than 1 to 10% of the time. In all 

cases, the IPC for short-term tropospheric interference permit a lower C/I, than that for 

continuous interfering signals. 

6.2.1.1 Television IPC in ITU-R Recommendations 

Rec. ITU-R BT.1368 provides IPC for the planning of DTV with respect to analog 

television.1

 Different IPC are required for planning DTV because the geographic 

distributions of field strength for DTV signals are not the same as those applicable to 

analog television signals. Table 6-2 defines IPC for protection of ATSC from ATSC for 

co-channel and adjacent channel conditions. 
 6-3

Table 6-2 

IPC for Protection of ATSC from ATSC Interference 

Unwanted Digital 

Channel 

Continuous and 

Tropospheric 

Interfering Signals 

Lower Adjacent C/I ≥ –27 dB 

Co-Channel C/I ≥ 15, 19i dB 

Upper Adjacent C/I ≥ –27 dB 

i

Based on I/N = 0 dB 

Table 6-3 defines IPC for protection of ATSC from NTSC for cochannel and 

adjacent channel conditions. 

Table 6-3 

IPC for Protection of ATSC from NTSC Interference 

Unwanted Digital 

Channel 

Continuous and 

Tropospheric 

Interfering Signals 

Lower Adjacent C/I ≥ –48 dB 

Co-Channel C/I ≥ 2, 7i dB 

Upper Adjacent C/I ≥ –49 dB 

i

Based on use of a comb filter and C/N ≥ 19 dB 

Table 6-4 defines IPC for protection of NTSC from ATSC under cochannel and 

adjacent channel sharing conditions and only short-term IPC are specified. 

. 

Table 6-4 

IPC for Protection of NTSC from ATSC Interference 

Unwanted Digital 

Channel 

Tropospheric Interfering 

Signals 

(1-10% of time) 

Lower Adjacent C/I ≥ –16 dB 

Co-Channel C/I ≥ 34 dB 

Upper Adjacent C/I ≥ –17, –12i dB 

i

For protection of NTSC sound signals 

In the case of interfering signals using an upper adjacent digital channel into an 

NTSC channel in Table 6-4, the NTSC audio signal degrades more than the video 

signal and requires a more restrictive IPC. 

Rec. ITU-R BT.655 lists IPC for protection of analog television from analog vision 

and sound signals.2 Unless otherwise stated, these IPC address tropospheric 
 6-4

interfering signals. Where IPC for continuous interfering signals are not available, yet 

required due to substantially non-fading unwanted signals, the tropospheric values of 

Table 6-5 increased by 10 dB may be used. 

Table 6-5 

IPC for Protection of NTSC from NTSC Interference 

Unwanted Channel Tropospheric Interfering Signals 

(1-10% of Time) 

Lower Adjacent C/I ≥ –13 dB 

Co-Channel C/I ≥ 45 dB 

Upper Adjacent C/I ≥ –10 dB 

When the interfering source is a CW signal, a vision signal positive modulated, or 

FM-sound, and the wanted signal is a vision signal negative modulated, the IPC in 

Table 6-6 apply.d

 If the interferer is a vision signal negative modulated or an AM-sound 

signal, a –2 dB and +4 dB offset, respectively, can be applied to the IPC values in Table 

6-6. 

Table 6-6 

IPC for Protection of Negative Modulated Vision NTSC Signal from CW, Positive 

Modulated Vision NTSC, and FM Sound Signals 

Δf (MHz) –1.5 –1.0 –.75 0.3 1.0 2.5 3.0 3.5 3.7 4.1 4.5 

C/I (dB) 0 30 40 50 50 37 45 50 50 45 15 

Δf = unwanted carrier frequency minus wanted carrier frequency 

Table 6-7 describes IPC for the case of a wanted FM sound signal and unwanted 

CW or FM sound carrier with various frequency offsets. 

 

d Vision modulation may be either positive or negative. With positive modulation, the sync pulse tips are 

held at the zero-modulation level, whilst peak white is 100% and black level around 30%. With negative 

modulation, the sync tips are at 100%, black level around 77% and peak white 20%. This method has 

the advantage that there is a portion of the waveform that is always at 100% modulation, so that the 

receiver can measure the carrier strength and adjust its automatic gain control accordingly. 
 6-5

Table 6-7 

IPC for an NTSC Wanted FM Sound Signal Interfered 

 with by an Unwanted CW or FM Sound Carrier 

Frequency Difference between Unwanted 

Wanted Sound Signal Carrier and Wanted Sound Carrier (kHz) 

0 15 50 250 

Tropospheric (C/I): 32 dB 30 dB 22 dB –6 dB FM Continuous (C/I): 39 dB 35 dB 24 dB –6 dB 

6.2.1.2 Television IPC in FCC Rules 

Section 73.525 of the FCC Rules defines protection requirements for NTSC TV 

channel 6 from FM radio signals for cochannel and adjacent channel operation as 

shown in Table 6-8.3

Table 6-8 

IPC for Protection of NTSC Channel 6 from FM Radio Interference 

Unwanted Channel C/I 

Co-channel: 

no offset 39 dB 

normal offseti 22 dB 

Adjacent-Channel: –12 dB 

i

 TV carrier offset by 10 kHz (Section 73.606) 

Section 73.623 of the FCC Rules defines IPC for various combinations of analog 

and DTV as shown in Table 6-9.4
 6-6

Table 6-9 

IPC for Protection of Analog and DTV 

Unwanted Channel C/I 

Co-channel: 

DTV into analog TV 34 dB 

Analog TV into DTV 2 dB 

DTV into DTV 15 dB 

 

First Adjacent Channel: 

Lower DTV into analog TV –14 dB 

Upper DTV into analog TV –17 dB 

Lower analog TV into DTV –48 dB 

Upper analog TV into DTV –49 dB 

Lower DTV into DTV –28 dB 

Upper DTV into DTV –26 dB 

According to Section 90.545 of the FCC regulations, public safety base, control, 

and mobile transmitters in the 764-776 MHz and 794-806 MHz bands are subject to the 

IPC to protect existing analog TV and DTV broadcast stations transmitting on TV 

channels 62, 63, 64, 65, 67, 68, and 69 as described in Table 6-10.5

Table 6-10 

IPC for Protection of Analog and DTV Stations 

from Public Safety Transmissions in 764-776 and 794-806 MHz Bands 

Unwanted Channel C/I

Co-channel:

Analog TVi 40 dB 

DTVii 17 dB 

 

First Adjacent Channel:

Analog TVi 0 dB 

DTVii –23 dB 

i At the hypothetical Grade B contour (64 dBμV/m) (85.5 km) of the analog 

TV station 

ii At the equivalent Grade B contour (41 dBμV/m) (88.5 km) of the DTV 

station 
 6-7

6.2.2 FM Radio Broadcast 

There is a similar thrust toward digital in the FM radio broadcast band except that 

there are no plans for reallocation. There are and will continue to be 101 FM radio 

channels numbered from 200 to 300 with each channel being 200 kHz wide. Channel 

200 is centered at 87.9 MHz; channel 201 is 88.1 MHz, and so forth through channel 

300, which is centered at 107.9 MHz. Channels 200 to 220 (87.9 to 91.9 MHz) are 

available for non-commercial educational purposes.e

 The transition to digital will allow 

broadcasters to transmit both analog and digital versions of their signal in the same 200 

kHz channel. This method, called IBOC (in-band on-channel), allows FM stations to 

transmit the digital signal on the sidebands above and below the FM band center 

frequency. During hybrid operation, existing (analog) receivers still continue to receive 

the analog signal. New receivers being developed are expected to incorporate both 

modes of reception. If the digital signal cannot be decoded or is lost by the receiver, the 

new receiver will automatically switch to the analog FM signal. 

The following subsections list IPC (C/I) of radio frequency signals at the receiver 

input, and are specifically chosen such that they achieve a defined level of demodulated 

audio frequency S/I at the receiver output. 

6.2.2.1 Broadcast FM Radio IPC in ITU-R Recommendations 

Rec. ITU-R BS.412 shows a list of IPC to protect monophonic and stereophonic 

desired signals from continuous and tropospheric interfering signal sources.6 The 

interfering signal sources are other broadcast FM radio signals. As expected the IPC 

shown in Table 6-11 decrease with increasing frequency separation between the 

desired and undesired carriers, with the exception of the stereophonic case where the 

IPC decreases only after first increasing through the first 50 kHz of separation. The 75 

kHz maximum deviation associated with the IPC in Table 6-11 corresponds to the limit 

for FM radio broadcasting within the United States.f

 

e

 Channel 200 (87.9 MHz) is available by certain Class D stations only on a non-interference basis to TV 

Channel 6 and adjacent channel non-commercial educational FM stations. 

f

 The 75 kHz maximum frequency deviation is specified under “Percentage modulation” in 47 CFR 

73.310. 
 6-8

Table 6-11 

FM Radio Broadcasting IPC 

C/I (dB) Using Maximum Frequency Deviation of ±75 kHz

Monophonic Stereophonic 

Carrier 

Frequency 

Separation 

(kHz) Continuous Tropospheric Continuous Tropospheric

0 

25 

50 

75 

100 

125 

150 

175 

200 

225 

250 

275 

300 

325 

350 

375 

400 

36.0 

31.0 

24.0 

16.0 

12.0 

9.5 

8.0 

7.0 

6.0 

4.5 

2.0 

–2.0 

–7.0 

–11.5 

–15.0 

–17.5 

–20.0 

28.0 

27.0 

22.0 

16.0 

12.0 

9.5 

8.0 

7.0 

6.0 

4.5 

2.0 

–2.0 

–7.0 

–11.5 

–15.0 

–17.5 

–20.0 

45.0 

51.0 

51.0 

45.0 

33.0 

24.5 

18.0 

11.0 

7.0 

4.5 

2.0 

–2.0 

–7.0 

–11.5 

–15.0 

–17.5 

–20.0 

37.0 

43.0 

43.0 

37.0 

25.0 

18.0 

14.0 

10.0 

7.0 

4.5 

2.0 

–2.0 

–7.0 

–11.5 

–15.0 

–17.5 

–20.0 

6.2.2.2 Broadcast FM Radio IPC in FCC Regulations 

The FCC Part 73 Rules define sharing criteria between FM radio stations in 

terms of minimum distance separations and do not specify general IPC values. 

However, as an exception defined in Sections 73.213 and 73.215, stations at locations 

authorized prior to November 16, 1964, that did not meet the separation distances 

required by Section 73.207 and have remained continuously short-spacedg

 since that 

time must meet the requirements defined in Table 6-12.7

 g

A site that does not meet the minimum separation requirement is “short spaced”. 
 6-9

TABLE 6-12 

IPC for Protection of Broadcast Radio from 

other Broadcast Radio Stationsh

Unwanted Channel C/I 

Co-channel i 20 dB 

First Adjacent Channel ii 6 dB 

I where the desired signal is based on field strength levels at 50% 

of all locations for 50% of the time 

iiwhere the undesired signal is based on a field strength levels at 

50% of their locations for 10% of the time 

6.3 BROADCASTING-SATELLITE SERVICE 

The Broadcasting-Satellite Service (BSS) broadcasts radio or television 

programming from earth orbiting satellites either directly to individual consumer 

households or to community antenna television (CATV) feeds. Currently there are BSS 

allocations between 30 MHz and 30 GHz serving the United States and Possessions in 

the following bands:i 

2310-2360 MHzj 

2500-2690 MHzk 

12.2-12.7 GHz

17.3-17.7 GHzl

The IPC for the BSS are typically expressed as wanted-to-unwanted signal 

power ratios (C/I) at the receiver input. The majority of these IPC are intended to 

protect against long-term interfering signals. Short-term IPC allow higher interfering 

signal levels, but for only a limited percentage of time. Some of these short-term IPC 

also limit the maximum amount by which the threshold may be exceeded so that the 

degradation may not actually result in a loss of service (outage) under otherwise ideal 

conditions. The IPC can also be expressed as a power flux density (pfd) within the BSS 

 

h

 IPC for radio stations not meeting the distance separation requirements. 

i

 All of these bands are allocated to the BSS for non-federal use only. j

 According to allocation footnote US327, the band 2310-2360 MHz is allocated to the BSS (sound) and 

complementary terrestrial BS on a primary basis. Such use is limited to digital audio broadcasting and is 

subject to the provisions of Resolution 528 of the ITU RR. k

 According to allocation footnote NG101, the band 2310-2360 MHz is allocated to the BSS (sound) and 

complementary terrestrial BS on a primary basis. Such use is limited to digital audio broadcasting and is 

subject to the provisions of Resolution 528 of the ITU RR. l

 This allocation will come into effect in 2007 (see allocation footnote NG163). 
 6-10

service area. In most of these cases the pfd is determined from C/I criteria, thus, C/I is 

the primary IPC listed in this section. 

One form of BSS IPC is expressed as overall C/I. The overall C/I value is the 

ratio of the wanted carrier power to the sum of all interfering signals in a given channel 

including both the feeder up links and service down links. This is depicted in equation 

(6-1). 

1 1 1 − − −

⎟

⎟

⎠

⎞

⎜

⎜

⎝

⎛ ⎟

⎠

⎞ ⎜

⎝

⎛ ⎟ + ⎠⎞ ⎜

⎝

⎛ ⎟ = ⎠⎞ ⎜

⎝

⎛

Overall Up Down I

C

I

C

I

C (6-1)

Where (C/I)overall, (C/I)up, and (C/I)down are numerical (not decibel) carrier to 

interfering signal power ratios for the overall end-to-end link, the up link, and down link, 

respectively. 

IPC for the BSS are expressed for adjacent channel as well as co-channel 

interfering signals. Co-channel IPC have no carrier frequency offset, which is defined 

as the difference between the unmodulated carrier frequencies of the unwanted and 

wanted signals if the same type of modulator is used in both channels. Adjacentchannel IPC are determined through a series of measurements made with frequencies 

of the unwanted signal varying approximately ±30 MHz from the wanted signal. Rec. 

ITU-R BO.1293 gives instructions on how to create adjacent channel interfering signal 

masks for protection of the BSS.8

IPC for video signals are determined through subjective means as described in 

Rec. ITU-R BO.600.9 The only noise that should be present on the picture when 

assessing protection ratios is the receiver thermal noise. The protection ratios are 

determined based on pictures having a signal-to-unweighted-noise ratio of not less than 

36 dB, in order that system performance should not be limited by possible masking of 

interfering signals by noise. 

The IPC for sound transmissions are determined through measurement by 

means of an objective method. Noise is measured after demodulation in order to obtain 

the condition that the signal-to-weighted-noise ratio within the sound channel does not 

exceed a specified value.m Table I of ITU-R BO.634-4 lists the parameters influencing 

the protection ratio for sound signal together with a suggested reference case to 

establish a common set of test conditions for measurements made by different 

administrations.10 ex-CCIR Report 796 specifies a measurement method for 

determination of IPC for sound.11 

 

m Weighting refers to the practice of filtering prior to measurement to reduce certain noise frequency 

components in a manner corresponding to human audio perception. Without weighting, the true S/N 

would be underestimated, because humans cannot perceive all the noise entering the measurement 

equipment. 
 6-11

The majority of IPC for BSS are defined for protecting analog signals. However, 

in the United States, BSS is implemented using digital techniques. 

The IPC for the BSS are primarily found in the Radio Regulations (RR) and ITUR Recommendations of the BO Series. The following sections describe the IPC by 

source. Key factors that influence the establishment of IPC values, including interfering 

signal type, allocation status of the interferer, and duration of the interfering signals, are 

also provided when available. 

6.3.1 Appendix 30 (AP30) of the ITU Radio Regulations12

Annex 3 of AP30 shows the IPC applicable for protecting the BSS from all types 

of terrestrial interfering signals.13 Figure 6-1 depicts the IPC and shows that there is a 

carrier frequency offset dependence for all terrestrial interfering signals except from 

amplitude modulated multi-channel television systems, in which case the IPC is a 

constant C/I = 35 dB. For all cases, the IPC are only applied when the necessary 

bandwidth of the terrestrial station overlaps the necessary bandwidth of the BSS 

assignment. 

0

10

20

30

40

-50 -40 -30 -20 -10 0 10 20 30 40 50

Carrier frequency difference (MHz)

Minimum C/I (dB)

Figure 6-1. Protection Ratio for BSS against a single entry terrestrial service 

(except AM multi-channel TV systems) 

In Section 3.4 of Annex 5 of AP30, the following aggregate IPC specify C/I values 

for protection of analog and digital assignments from analog television signals: 24 dB 

(co-channel), 16 dB (adjacent channel). The following IPC specify C/I values for 

protection of digital assignments from digital emissions: 21 dB (co-channel) 16 dB 

(adjacent channel). 

For protection of FM-TV from other FM-TV transmissions, Figure 6-2 shows an 

IPC template of C/I values as a function of carrier frequency offset. 
 6-12

-16

-8

0

8

16

24

32

-30 -20 -10 0 10 20 30

Carrier frequency difference (MHz)

Minimum C/I (dB)

Figure 6-2. Protection Ratio template (FMTV/FMTV), 

for planning of BSS systems in Region 2 

Section 3 of Annex 1 of AP30 includes a section on IPC protecting the BSS in 

Regions 1 and 2 in the band 12.2-12.5 GHz and in Region 3 in the band 12.5-12.7 GHz 

from other proposed like assignments.14 These IPC are intended to protect 

assignments in Regions 1 and 3 from proposals in Region 2, and vice versa. 

Annex 6 of AP30 provides protection requirements for sharing between services 

in the 12 GHz band. The IPC are provided as C/I with the stipulation that interfering 

signal levels shall not be exceeded for 99% of the worst month. The C/I values for BSS 

protect TV/FM signals from TV/FM signals of the BSS, FSS, FS, and BS. The C/I 

values listed are 30 dB for aggregate interfering signals, and 35 dB for single-entry 

interfering signals. Figure 6-3 shows how much these values are reduced as a function 

of carrier frequency offset. 

-30

-20

-10

0

-30 -20 -10 0 10 20 30

Carrier frequency difference (MHz)

Relative protection ratio (dB)

Figure 6-3. Reference case protection ratios relative to co-channel values 
 6-13

6.3.2 Recommendation ITU-R BO.129715

This Recommendation suggests that the IPC in RR AP30 and AP30A for BSS 

and associated feeder links were inadequate due to technological improvements made 

in the BSS. It proposes the IPC shown in Table 6-13. All IPC are specified as C/I 

where I represents the aggregate interfering signal. The IPC for the overall path are 

based on equation (6-1). 

Table 6-13 

Aggregate Protection Ratios for Planning Revision of RR AP30 and AP30A 

in Regions 1 and 3 

Co-channel Protection 

Criteria 

Adjacent Channel 

Protection Criteria 

Feeder link path C/I ≥ 30 dB C/I ≥ 22 dB 

Down link path C/I ≥ 24 dB C/I ≥ 16 dB 

Overall path C/I ≥ 23 dB C/I ≥ 15 dB 

6.3.3 Recommendation ITU-R BO.144416

This Recommendation provides guidance for protecting the 12 GHz BSS and 

associated 17 GHz feeder links from the earth and space station emissions of all nonGSO (NGSO) FSS satellite networks operating in the same frequency band. It states 

that these NGSO FSS emissions may be responsible for at most 10% of the time 

allowance(s) for unavailability of the given C/N value(s) as specified in the performance 

objectives of the desired network, where N is the total noise level in the noise bandwidth 

associated with the wanted carrier including all other non-time-varying interfering 

signals. This seems to indicate that NGSO FSS can exceed a C/(N+I) which is equal to 

the required BSS C/N (including margins) for 10% of the permitted outage, where I only 

includes the aggregate of NGSO FSS emissions. This is less strict than requiring that I 

include other unwanted NGSO FSS networks. 

The Recommendation also indicates that at no time should interfering signals 

lead to a loss of video picture continuity in the desired digital GSO BSS and associated 

feeder-link network under clear-sky conditions. Loss of video picture continuity includes 

error concealment mechanisms such as “freeze frame” (repeat last frame), blank (black) 

frame, or other techniques. The clear sky link margins above these video picture 

continuity thresholds must also be specified. If none are indicated, 1.5 dB is assumed. 

ITU-R BO.1444 also points out that the impact of interfering signals on degradation is 

dependent on rain. Specifically, rain increases system noise temperature and 

attenuates the interfering and desired signals. 
 6-14

6.3.4 FCC Report and Order 00-41817

Pursuant to this document, Section 101.105 of CFR Title 47 allows MVDDS 

transmitters to increase Direct Broadcast Satellite (DBS) outage at 12 GHz by up to 

2.86% or up to 10 minutes per month.n

 Certain DBS providers have proposed that the 

10% additional outage applied to the aggregate from all other competing uses of the 12 

GHz band, whereas the 2.86% additional outage applied to any one provider (e.g. 

MVDDS).18 Included in that document is a section (Appendix H) that proposes a 

method for converting percentage of unavailable time into a C/I value. 

6.3.5 Mitre Technical Report19 

The Mitre Corporation was hired by the FCC to study the DBS and MVDDS 

compatibility issue.20 Among other things, the report created a rain attenuation model 

and used it to determine minimum C/I criteria for various U.S. cities as a function of 

percentage increase of unavailability of a particular DBS satellite. Table 6-14 

represents the case where MVDDS increases DBS unavailability by 10%. These values 

are based on equation (6-2) below, where the effects of MVDDS are included in an 

effective rain margin, AeRm. For their study, Mitre assumed that the interfering signal 

was not attenuated during a DBS rain event.o 

Table 6-14 

Minimum C/I to Satisfy 10% Additional Link Outage (MVDDS interfering with DBS) 

Location Minimum C/I 

(dB) 

Boston, MA 23.8 

Chicago, IL 23.7 

Denver, CO 27.3 

Fargo, ND 25.7 

Houston, TX 22.4 

Los Angeles, CA 22.1 

Miami, FL 21.9 

Phoenix, AZ 21.6 

Seattle, WA 25.5 

Washington, D.C. 22.9 

eRm

required rainy sky

A

I

C

I

C ⎟ + ⎠

⎞ ⎜

⎝

⎛ ⎟ = ⎠⎞ ⎜

⎝

⎛ (6-2)

 

n

 MVDDS refers to Multi-channel Video Distribution and Data Service. o

 DBS earth stations were pointed toward the southern hemisphere, whereas MVDDS sites were 

assumed to be to the north, and possibly unaffected by the same rain fronts. 
 6-15

In Equation (6-2), (C/I)required is the minimum acceptable single-entry clear-sky 

IPC, (C/I)rainy sky are the IPC in the presence of rain without considering the effects of 

MVDDS, and AeRm is the effective rain margin plus another margin to account for the 

increased aggregate due to the presence of MVDDS.p

6.3.6 Spectrum XXI 

Spectrum XXI is a program intended for use by all government agencies to aid in 

submitting systems for spectrum authorization by NTIA. Included in the program is an 

IPC table to aid in interference analyses. To protect broadcasting systems Spectrum 

XXI recommends the use of I/N = –10 dB. This IPC is believed to be a conservative 

value intended for an initial test for harmful interference. If a potential interference 

source passes this test, compatibility is assumed without any further analyses. 

6.3.7 Further Study 

More work must be done to determine appropriate IPC involving digital signals. 

ITU-R Report 634-4 suggests the test matrix given in Table 6-15: 

Table 6-15 

Wanted and Unwanted Signal Interactions Requiring Further Study 

Wanted Signal Unwanted Signal 

Digital Digital 

Digital FM 

FM Digital 

Digital AM-VSBq

AM-VSB Digital 

Rec. ITU-R BO.600 provides a basis for further studies needed to define more 

precisely the test conditions and procedures for developing BSS IPC for digital 

modulation. More study is also needed to determine IPC for protection of digital BSS 

signals from pulsed interfering signals due to planned adjacent band reallocation at 17 

GHz. 

 

p

 Rain margin (ARm) simply accounts for the decrease in C due to rain. AeRm also accounts for the 

increase in I due to the presence of MVDDS. 

q

 VSB refers to vestigial side-band. 
 6-16

6.4 SUMMARY 

Table 6-16 contains a summary of IPC for the BS and BSS.
TABLE 6- 16 

Co-channel IPC Summary Table for BS and BSS 

6-17

Service/Systems Frequency 

Bands 

Interference Protection

CW and 

Noise 

Pulse/ 

Other i

Reference 

Bandwidth 

% 

Time 

Source 

Document 

BS (ATSC) 54-794 MHz N/S C/I ≥ 15 dB N/S >50 Rec. ITU-R BT.1368 BS (ATSC) 54-794 MHz N/S C/I ≥ 19 dB N/S >50 Rec. ITU-R BT.1368 BS (ATSC) 54-794 MHz N/S C/I ≥ 2 dB N/S >50 Rec. ITU-R BT.1368 BS (ATSC) 54-794 MHz N/S C/I ≥ 7 dB N/S >50 Rec. ITU-R BT.1368 

BS (NTSC vision) 54-794 MHz N/S C/I ≥ 34 dB N/S Rec. ITU-R BT.1368 

BS (NTSC) 54-794 MHz N/S C/I ≥ 45 dB N/S 1-10 Rec. ITU-R BT.655 BS (NTSC) 54-794 MHz N/S C/I ≥ 55 dB N/S >50 Rec. ITU-R BT.655 

BS (TV FM sound) 54-794 MHz C/I ≥ 32 dB C/I ≥ 32 dB N/S 1-10 Rec. ITU-R BT.655 BS (TV FM sound) 54-794 MHz C/I ≥ 39 dB C/I ≥ 39 dB N/S >50 Rec. ITU-R BT.655 

BS (TV channel 6) 54-794 MHz N/S D/U ≥ 39 dB N/S N/S Part 73.525 

BS (analog TV) 54-794 MHz N/S D/U ≥ 34 dB N/S N/S Part 73.623 

BS (DTV) 54-794 MHz N/S D/U ≥ 2 dB N/S N/S Part 73.623 BS (DTV) 54-794 MHz N/S D/U ≥ 15 dB N/S N/S Part 73.623 
TABLE 6- 16 

Co-channel IPC Summary Table for BS and BSS 

6-18

Service/Systems Frequency 

Bands 

Interference Protection

CW and 

Noise 

Pulse/ 

Other i

Reference 

Bandwidth 

% 

Time 

Source 

Document 

BS (NTSC) 764-776 MHz 794-806 MHz N/S D/U ≥ 40 dB N/S N/S Part 90.545 

BS (DTV) 764-776 MHz 794-806 MHz N/S D/U ≥ 17 dB N/S N/S Part 90.545 

BS (stereo FM 

radio) 88-108 MHz N/S C/I ≥ 45 dB N/S N/S Rec. ITU-R BS.412 

BS (stereo FM 

radio) 88-108 MHz N/S C/I ≥ 37 dB N/S N/S Rec. ITU-R BS.412 

BSS earth station 11.7-12.5 GHz N/S C/I ≥ 21 dB N/S N/S Article 11, AP30-61 BSS earth station 12.2-12.7GHz (Region 2) C/I ≥ 35 dB N/S N/S N/S Annex 3, AP30-88 BSS earth station 

(analog and digital) Any N/S C/I ≥ 24 dB N/S N/S AP30-109 

BSS earth station 

(digital) All Bands N/S C/I ≥ 21 dB N/S N/S AP30-110 

BSS earth station 

(FM/TV) All Bands N/S C/I ≥ 28 dB N/S N/S AP30-111 
TABLE 6- 16 

Co-channel IPC Summary Table for BS and BSS 

6-19

Service/Systems Frequency 

Bands 

Interference Protection

CW and 

Noise 

Pulse/ 

Other i

Reference 

Bandwidth 

% 

Time 

Source 

Document 

BSS space station 17.3-18.1 GHz N/S I/N ≥ –14 dB N/S N/S AP30A-128 BSS space station 17.8-18.1 GHz N/S I/N ≥ –15.2 dB N/S N/S AP30A-128 

BSS TV/FM 12 GHz N/S 

C/I ≥ 30 dB 

aggregate 

C/I ≥ 35 dB 

single-entry 

N/S N/S AP30-131 

BSS earth stations 17.3-17.8 GHz N/S I/N ≥ –18 dB N/S N/S ITU-R Doc 4-9-11/90-E 

BSS Feeder Link All Bands N/S C/I ≥ 30 dB N/S N/S Rec. ITU-R BO.1297 

BSS earth stations 12 GHz N/S C/I ≥ 27.3 dB N/S 10% Mitre Technical Report 

Broadcasting All Bands I/N = -10 dB I/N ≤ -10 dB N/S N/S Spectrum XX

I Other refers to interference from BS and BSS system. 
6-20 

REFERENCES 

1

 Rec. ITU-R BT.1368, Planning criteria for digital terrestrial television services in the 

VHF/UHF bands (2002). 

2

 Rec. ITU-R BT.655, Radio-frequency protection ratios for AM vestigial sideband 

terrestrial television systems interfered with by unwanted analog vision signals and their 

associated sound signals (2000). 

3

 47 CFR 73.525, TV Channel 6 protection, Federal Communications Commission 

(October 2002). 

4

 Telecommunications, Part 73, Section 623, DTV applications and changes to DTV 

allotments, Federal Communications Commission (October 2002). 

5

 47 CFR 90.545, TV/DTV interference protection criteria, Federal Communications 

Commission (October 2002). 

6

 Rec. ITU-R BS.412, Planning standards for terrestrial FM sound broadcasting at VHF

(1998). 

7

 47, CFR 73.213, Federal Communications Commission (2002); 47 CFR 73.215, 

Contour protection for short spaced assignments, Federal Communications (2002). 

8

 Rec. ITU-R BO.1293-1, Protection Masks and Associated Calculation Methods for 

Interference into Broadcast-Satellite Systems Involving Digital Emissions (2000). 

9

 Rec. ITU-R BO.600-1, Standardized set of test conditions and measurement 

procedures for the subjective and objective determination of protection ratios for 

television in the terrestrial broadcasting and the broadcasting-satellite services (1986). 

10 Reports of the CCIR, Annex to Volumes X and XI – Part 2, Report 634-4, 

Broadcasting-Satellite Service (Sound and Television) Measured interference protection 

ratios for planning television broadcasting systems (1990). 

11 Recommendations and Reports of the CCIR, Volume X, Broadcasting Service 

(Sound), Report 796, Determination of Radio-Frequency Protection Ratio for 

Frequency-Modulation Broadcasting Receivers (1978). 

12 Appendix 30, of the ITU Radio Regulations, Provisions for all services and associated 

Plans and List for the broadcasting-satellite service in the frequency bands 11.7-12.2 

GHz (n Region 3), 11.7-12.5 GHz (in Region 1) and 12.2-12.7 GHz (in Region 2) 

(2001). 
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6-21

13 Appendix 30 of the ITU Radio Regulations, Annex 3, Method for determining the 

limiting interfering power flux-density at the edge of a broadcasting-satellite service area 

in the frequency bands 11.7-12.2 GHz. (in Region 3), 11.7-12.5 GHz (in Region 1) and 

12.2-12.7 GHz (in Region 2) and for calculating the power flux-density produced there 

by a terrestrial station (2001). 

14 Appendix 30 of the ITU Regulations, Annex 1, Section 3, Limits to the change in 

power flux-density to protect the broadcasting-satellite service in Regions 1 and 2 in the 

band 12.2-12.5 GHz and in Region 3 in the band 12.5-12.7 GHz (2001).

15 Rec. ITU-R BO.1297, Protection Ratios to be Used for Planning Purposes in the 

Revision of the Appendices 30 (Orb-85) and 30A (Orb-88) Plans of the Radio 

Regulations in Regions 1 and 3 (1997). 

16 Rec. ITU-R BO.1444, Protection of the BSS in the 12 GHz band and associated 

feeder links in the 17 GHz band from interference caused by non GSO FSS systems

(2000). 

17 Authorizing Multi Video Distribution and Data Service in the Direct Broadcast Satellite 

Band at 12 Ghz, First Report and Order and Further Notice of Proposal Rule Making, 

ET Docket No. 98-206, RM-9147, RM-9245, FCC 00-418, 16 F.C.C. Rcd 4096 (2000). 

18 Amendments of parts 2 and 25 of the Commission ‘s Rules to permit operation of 

NGSO FSS systems co-frequency with GSO and terrestrial systems in the Ku-band 

frequency range; For the Memorandum Opinion and Order, ET Docket No. 98-206. 

FCC, 03-97, 18 F.C.C. Rcd.8428, 8435, n. 47 (2003).FCC 03-97 (FCC 03-97), page 7, 

footnote 47 for more information. 

19 Mitre Technical Report, Analysis of Potential MVDDS Interference to DBS in the 12.2-

12.7 GHz Band, Mitre Corporation, McLean, Virginia (April 2001). 

20 FCC 03-97, §7. 
6-22 

This page intentionally blank
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7-1

SECTION 7 

MOBILE AND MOBILE SATELLITE SERVICES 

7.1 INTRODUCTION 

Various station classes operate in the Mobile Service (MS) and the Mobile 

Satellite Service (MSS) within the 30 MHz to 30 GHz frequency range. The MS is 

further subdivided into the following services: land mobile (LMS), maritime mobile 

(MMS), aeronautical mobile (AMS), aeronautical mobile route (AM(R)S),a

 and 

aeronautical mobile off-route (AM(OR)S) services.b

 The MSS includes the following 

services: land mobile-satellite (LMSS), maritime mobile-satellite (MMSS), aeronautical 

mobile-satellite (AMSS), aeronautical mobile-satellite route (AMS(R)S), and 

aeronautical mobile-satellite off-route (AMS(OR)S) services. 

7.2 MOBILE SERVICE 

7.2.1 Mobile Service in General 

For the MS, the nature of the interfering signal source (i.e., CW, noise, pulse, and 

impulse) was not always defined with the IPC in the various reference sources. The 

IPC extracted from the references are for co-channel operations unless otherwise 

stated. The percentages of time and locations for which the IPC apply were not 

provided in most cases. 

• NTIA Manual (Annex I) 

Annex I of the NTIA Manual describes a procedure to evaluate interference in the 

162-174 MHz and 406-420 MHz bands, both of which have a primary allocation for the 

MS.1

 Annex I provides receiver sensitivity (desired signal power) values in the presence 

of low, average, and high noise environments.c These values are also intended to 

represent interfering signal thresholds. Table 1 of Annex I states that unacceptable 

interference may result if predicted received interfering signal power levels exceeds this 

threshold for more than 10% of the time at 50% of the locations. 

• Spectrum XXI 

For digital mobile systems Spectrum XXId uses I/N = –6 dB for the MS.2 This is 

 

a

 The R designation indicates communications relating to safety and regularity of flights primarily along 

national or international civil air routes.

b The (OR) designation indicates communications primarily outside national or international civil air 

routes. c

 This noise refers to the RF noise environment. 

d Spectrum XXI is a program intended for use by all government agencies to aid in submitting systems for 

spectrum approval by NTIA. 
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7-2

based on allowing interfering signals to cause a 1 dB increase in the receiver noise 

level. For analog mobile systems, an IPC of I/N = 0 dB is specified. 

• ITU Report 

CCIR Report 826 shows IPC for AM and FM voice systems and interfering 

signals from direct sequence (DS) and frequency hopping (FH)e

 spread spectrum 

transmissions and similar interfering signal sources.3 Characteristics of the desired 

signals analyzed are shown in Table 7-1. 

Table 7-1 

Characteristics of Mobile Systems Analyzed 

Modulation 

Typei

Receiver 

IF 

Bandwidth 

(kHz) 

Receiver 

Antenna 

Gain 

(dBi) 

Receiver 

Noise 

Figure 

(dB) 

Modulation 

Index 

Peak 

Deviation 

(kHz) 

E.I.R.P. 

(dBm) 

A3E 8 3 6 1.0 N/S 50 

F3E 16 3 6 1.67 ±5 50 

 i A3E indicates amplitude modulated double-sideband analog voice. F3E indicates 

frequency modulated analog voice. 

Table 7-2 provides the range of pulse widths and repetition rates over which the 

measurements were taken to determine the IPC for FH interfering signals. All IPC 

associated with this source are listed in Table 7-3 according to two performance levels. 

The two performance levels were taken to be articulation index (AI) values of 0.7 and 

0.9, where AI is a measure of voice intelligibility. The 0.7 AI threshold value marks the 

point at which degradation to intelligibility begins to appear, and the 0.9 value is the 

threshold between marginally commercial and good commercial quality. The IPC stated 

are conservative values insofar as they are the greatest S/I required to ensure an AI of 

at least 0.7 or 0.9 for all values of pulse width, pulse repetition frequency and off-tuning 

for which measurements had been performed. 

Table 7-2 

Parameter Ranges for FHSS Interfering Signal Measurements 

Pulse Width (μs) Pulse Repetition Frequency 

(pps) Modulation 

Type From To From To 

A3E 5 1000 10 400 

F3E 1 1000 40 1000 

 

e

 The FH signal was treated as a pulsed signal. 
SWITCH 

7-3

Table 7-3 

IPC to Protect against Various Interfering Signal Types 

IPC for Interference Typei Modulation 

Type Same DSSS FHSS 

Comments 

S/I ≥ 7 dB for 

AI = 0.7 

S/I ≥ 21 dB 

for AI = 0.7 

S/I ≥ 19 dB 

for AI = 0.7 A3E S/I ≥ 13 dB 

for AI = 0.9 

S/I ≥ 28 dB 

for AI = 0.9 

S/I ≥ 31 dB 

for AI = 0.9 

S/N ≥ 45 dB is assumed for 

the protected system. 

S/I ≥ 6 dB 

for AI = 0.7 

S/I ≥ 8 dB 

for AI = 0.7 

S/I ≥ 19 dB 

for AI = 0.7 F3E S/I ≥ 20 dB 

for AI = 0.9 

S/I ≥ 15 dB 

for AI = 0.9 

S/I ≥ 30 dB 

for AI = 0.9 

S/N ≥ 22 dB is assumed for 

the protected system. 

i DSSS is direct sequence spread spectrum, FHSS is frequency hopping spread 

spectrum, “Same” indicates that the interfering signal has the same modulation as 

the desired signal.

7.2.2 Land Mobile Service 

The following subsections describe IPC for protection of the LMS. 

7.2.2.1 Federal Government Standards 

• National Telecommunications and Information Administration 

Appendix D of NTIA Spectrum Reallocation Final Report listed indoor and 

outdoor interfering signal thresholds at –117 and –119 dBm, respectively for personal 

communications services (PCS) operating at 1850-1990 MHz.4

 This assumed an 

allocation of 10% of the total interference budget to external interfering signal sources. 

These threshold values were extracted from Rec. ITU-R M.687.5

NTIA Special Publication 01-46 “The Potential for Accommodating Third 

Generation Mobile Systems in the 1710-1850 MHz Band” provides two IPC thresholds 

for IMT-2000 Mobile and Base Stations that are listed in Table 7-5, depending on the 

type of modulation and access technique.6

 For example, for mobile stations, an I value 

of -110 dBm for Code Division Multiple Access (CDMA) for a bandwidth of 1.25 MHz, 

and an I value of -131 dBm (Enhanced Data Rates for GSM Evolution Edge) for a 0.03 

MHz bandwidth for land mobile base stations. The thresholds provided in the report 

were the most recent industry-approved characteristics, but actual 3G systems may 

have different parameters. 

NTIA TM 87-122 presents operational and performance characteristics of radios 

equipped with the Data Encryption Standard.7

 A portion of the report describes a 

capture effect inherent in FM systems that causes the wanted signal to reduce 
SWITCH 

7-4

interference from the unwanted signal when the received wanted signal is stronger than 

the unwanted signal by the amount of the capture ratio. For the analog mode the 

capture ratio varied from 2 dB at a high S/N to 5 dB at a low S/N. In the digital mode 

the capture ratios ranged between 2 and 15 dB for high and low S/N conditions 

respectively. 

• Federal Communications Commission 

The following FCC Rules from Title 47 of the Code of Federal Regulations, were 

investigated for potential IPC: Part 22 (Public Mobile Services), Part 24 (Personal 

Communications Services), Part 27 (Miscellaneous Wireless Communications 

Services), Part 80 (Stations in the Maritime Service) Part 90 (Private Land Mobile Radio 

Services), Part 95 (Personal Radio Services). 

Section 90.187 of the Commission Rules discusses interference from trunked 

systems to conventional VHF and UHF networks. A subsection defines objectionable 

interference as occurring when the interfering signal contour (19 dBμ for VHF, and 21 

dBμ for UHF) of a proposed trunked station would intersect the service contour (37 dBμ

for VHF, and 39 dBμ for UHF) of an existing station. This is equivalent to a protection 

ratio of 18 dB. 

Section 80.773 of the Commission Rules states that a VHF public coastal station 

that shares a frequency with an incumbent private land mobile radio (PLMR), the 

coastal station must provide a 10 dB or greater protection ratio with respect to the 

PLMR signal level. 

7.2.2.2 Industry Association Standards 

Telecommunications Industry Association (TIA) 

TIA TSB 88-A provides a section called “Interference Prediction” which states: “It 

is assumed that for any modulation combination, it is valid to treat adjacent channel 

interference as additional noise power that enters a receiver’s IF filter”.8

 Interference 

between different modulation types may be calculated based on the power spectrum of 

the given transmitter modulation and the IF filter selectivity and IF C/N for a specified 

channel performance criterion (CPC)f in a Rayleigh faded channel. The C/(I+N) then 

becomes a predictor of CPC.” TIA TSB 88-A provides a list of various modulation types 

with associated IPC for various delivered audio quality (DAQ)g ratings and desired BER. 

Portions of the contents of this table are listed in Table 7-5. 

 

f

 CPC is a measure of the BER and vehicular Doppler fading rate required to deliver a specific mean 

opinion score (MOS) for the specific modulation. 

g

 DAQ is a measure similar to Circuit Merit with additional definitions for digitized voice and a static 

SINAD equivalent intelligibility when subjected to multipath fading. 
SWITCH 

7-5

7.2.2.3 International Recommendations 

International Telecommunication Union 

Rec. ITU-R M.687-2 estimates the level of interfering signals in IMT-2000 

receivers that can be tolerated using a link power budget based on personal mobile 

systems being interference limited, rather than noise limited. As a basis for IPC, 10% of 

the total interference budget is allocated to the external interfering signal sources. The 

IPC specify maximum permissible aggregate interfering signal power levels that can be 

received by personal stations without significantly degrading the quality of service. 

Rec. ITU-R M.1073 deals with LMS cellular communications in the bands at 800, 

900, 1800, and 1900 MHz ranges.9

 Section 4.4 indicates that a co-channel protection 

ratio of C/I = 9 dB is permissible and accommodates a possible cellular frequency reuse 

corresponding to a 9-cell cluster. 

Rec. ITU-R M.1388 provides a coordination threshold level to protect a digital 

system in the LMS, which is already operating in the 1452-1492 MHz band in one 

country from proposed space stations in the Broadcasting Satellite Service.10 The 

threshold is –150 dB(W/m2) in 4 kHz bandwidth for all angles of arrival and applies as a 

general protection criterion for the LMS in that band until additional studies are 

completed. 

Annex 2 of Rec. ITU-R SM.851 provides IPC for protection of land mobile 

services from the BS.11 The listed IPC protect only analog and some digital voice land 

mobile systems from analog AM vestigial sideband television and analog FM audio 

broadcasting signals. For television signals, IPC are specified for land mobile channels 

that fall within 0.5 MHz of the vision carrier. For FM audio broadcasting signals, IPC are 

listed as a function of frequency separation between carriers of the two services. Rec. 

ITU-R SM. 851 also notes that since the IPC are based on interfering signals using the 

same type of modulation as the wanted signal, correction factors may be required 

before applying them to sharing with the BS. The IPC from this source are listed in 

Table 7-5. 

7.2.3 Maritime Mobile Service 

The following subsections list IPC for protection of MMS systems. 

7.2.3.1 Federal Agencies 

• National Telecommunications Information Administration 

NTIA Report 99-362 evaluates the performance of various 25 kHz marine 

radios.12 Specifically, the objectives of this report were to: 

1) measure the SINAD of marine radios operating in a shipboard environment; 
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7-6

2) identify the sources of interference and interference mechanisms; and 

3) investigate ways to mitigate and preclude the interference. 

NTIA Report 00-376 investigates EMC between marine automatic identification 

(AIS) and public correspondence (PC) systems in the maritime mobile VHF band.13 

Both closed system and radiated tests were performed on PC and AIS operations for 

different frequency offsets. The test results were given in terms of interference-to-signal 

(I/S) power ratios for different test conditions and scenarios. Further evaluation is 

required to determine if IPC can be developed from the test results. 

NTIA Report 00-343 assesses the compatibility between 25 and 12.5 kHz 

channelized marine VHF radios.14 Specifically, the objectives of the report were to: 

 1) determine the susceptibility of various 12.5 kHz and 25 kHz radios to 

adjacent/interstitial channel interference, and 

2) evaluate the interoperability of various 12.5 kHz and 25 kHz radios. 

Both bench and radiated tests and results were conducted and results were provided in 

terms of S/I values. Further evaluation is required to determine if IPC can be developed 

from the test results. 

NTIA Report 99-363 assesses various 25 kHz radios to determine compliance 

with the performance standards for marine VHF radio receivers contained in 

International Electrotechnical Commission (IEC) document 1097-7.15 Specifically, tests 

were performed to determine: sensitivity, co-channel rejection ratio, adjacent channel 

selectivity, intermodulation response, and blocking. Testing results are provided in 

terms of I/S power ratios. Further evaluation is required to determine if IPC can be 

developed from the test results. 

• Federal Communications Commission 

Section 80.773 of the FCC Rules “Co-channel interference protection” states 

“Where a VHF public coast station geographic area licensee shares a frequency with an 

incumbent VHF public coast station licensee, the ratio of desired to undesired signal 

strengths must be at least 12 dB within the service area of the station.” These IPC are 

listed in Table 7-5. 

7.2.4 Aeronautical Mobile Service 

The following subsections describe IPC for protection of AMS systems. 

7.2.4.1 International Recommendations 

International Civil Aviation Organization (ICAO) 

ICAO Annex 10, Volume V specifies provisions concerning the deployment of 
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7-7

VHF frequencies and avoidance of harmful interference.16 Section 4.1.5.1 indicates that 

points at the protection heights and at the limit of the functional service range of each 

facility are separated by distances not less than that required to provide a desired to 

undesired signal power ratio of 14 dB. Attachment A to that section states that the 

application of the 14 dB planning criteria assumes that it is highly unlikely that two 

aircraft will be at the maximum edge of their respective service volumes and at the 

closest point between these two volumes. 

7.3 MOBILE SATELLITE SERVICE 

For the MSS, the only sources of IPC are the ITU-R M series Recommendations. 

For digital MSS carriers, the IPC are specified as apportionment of the total noise. A 

summary of these Recommendations for various types of systems is listed in Table 7-4. 

Table 7-4 

List of ITU-M Recommendations Related to IPC for the MSS 

ITU-R Recommendations 

System Performance 

Objective 

Interfering Signal 

Power Apportionment 

MMSS voice circuit M.54717 N/S 

MMSS telegraph M.55218 N/S 

GSO/AMSS non-ISDN M.122919 M.118320

GSO/AMS(R)S M.103721 M.123422

GSO/MSS ISDN M.147623 M.1183 

GSO/MSS non-ISDN M.118124 M.1183 

NGSO/MSS downlink M.123025 M.123126, M.123227

NGSO/MSS Cospas-SarSat uplink M.147828 M.1478 

7.3.1 Geostationary Satellite Service 

From Rec. ITU-R M.1183, for a GSO/MSS digital channel in the 1-3 GHz band, 

the permissible levels of interference caused by other GSO/MSS systems and 

GSO/FSS systems should exceed the levels shown in Table 7-6 for no more than (100-

x)% of any month. Here x is the percentage of time availability as defined under the 

relevant ITU-R Recommendations on performance objectives (Table 7-4). The total 

noise power is defined as the noise power at the input of the demodulator, which gives 

rise to the desired performance. 

From Rec. ITU-R M.1234, for a GSO/AMS(R)S digital channel in the bands 1545 

to 1555 MHz and 1646.5 to 1656.5 MHz, the permissible level of interference caused by 

other AMS(R)S, AMSS, and FSS should not exceed: 

• for aggregate interfering signals, 20% of total noise power, 
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7-8

• for single-entry interfering signals, 6% of total noise power. 

Here the total noise power is defined as the noise power at the input to the 

demodulator, which would give rise to the BER performance objective specified in Rec. 

ITU-R M.1037. 

7.3.2 Nongeostationary Satellite Service - Downlink 

From Rec. ITU-R M.1231, for FDMA and spread spectrum multiple access 

(SSMA) NGSO/MSS downlinks in the 137-138 MHz band, the maximum aggregate 

interfering signal level at the input of the receiving antenna is specified in Table 7-6. 

The data are derived based on two sample systems addressed in Rec. ITU-R M.1231. 

From Rec. ITU-R M.1232, for FDMA or SSMA NGSO/MSS downlinks in the 137-

138 MHz band, the maximum single-entry interfering signal level at the input of the 

receiving antenna from a NGSO/MSS system or any non-MSS system is specified in 

Table 7-6. These IPC are derived assuming two interfering NGSO/MSS systems and 

one interfering terrestrial system. 

7.3.3 NGSO Satellite Service (Cospas-Sarsat Uplink) 

From Rec. ITU-R M.1478, the protection criteria for Cospas-Sarsat uplinks 

operating in the 406-406.1 MHz band are specified in terms of interfering signal power 

flux density (pfd) or spectral pfd (spfd) at the Cospas-Sarsat satellite receive antenna. 

These IPC are listed in Table 7-6. 

7.4 SUMMARY 

A summary of the IPC for the MS and MSS are provided in Tables 7-5 and 7-6 

respectively. 
SWITCH 

Table 7-5 

Summary of IPC for Digital Channels in the Mobile Services 

7-9

Systems/ Interference Protection 

Services 

Frequency 

Bands CW/Noise Pulse/ 

Other 

Reference 

bandwidth

% 

Time 

Source 

Document

Mobile 

162-174 and 

406.1-420 

MHz 

I/N ≤ 0 dB N/S IF Passband 10 NTIA Manual Annex I I/N of 

exce

5

Mobile 

(Digital) 

30-1215 

MHz I/N ≤ –6 dB N/S IF Passband N/S Spectrum XXI 

Mobile 

(Analog) 

30-1215 

MHz I/N ≤ 0 dB N/S IF Passband N/S Spectrum XXI 

S/I ≥ 21 dB 

(AI = 0.7) 

S/I ≥ 19 dB 

(AI = 0.7) 

S/I ≥ 28 dB 

(AI = 0.9) 

S/I ≥ 31 dB 

(AI = 0.9) 

N/S N/S 

Assu

IPC f

for 

S/I ≥ 7 dB 

(AI = 0.7) 

Mobile 

(AM DoubleSideband 

Voice) 

All 

N/S S/I ≥ 13 dB 

(AI = 0.9) 

N/S N/S 

CCIR 

Report 

826 Assu

IPC f

for A3

S/I ≥ 8 dB 

(AI =0.7) 

S/I ≥ 19 dB 

(AI = 0.7) 

S/I ≥ 15 dB 

(AI = 0.9) 

S/I ≥ 30 dB 

 (AI = 0.9) 

N/S N/S 

Assu

IPC f

for 

S/I ≥ 6 dB 

(AI = 0.7) 

Mobile 

(FM Voice) All 

N/S S/I ≥ 20 dB 

(AI = 0.9) 

N/S N/S 

CCIR 

Report 

826 

Assu

IPC f

for F3
SWITCH 

Table 7-5(cont) 

Summary of IPC for Digital Channels in the Mobile Services 

7-10

CW/Noise Pulse/ 

Other 

I ≤ –117 

dBm 

(Indoor) 

Land Mobile 

(IMT-2000 

and PCS 

personal 

stations) 

Below 3 

GHz I ≤ –119 

dBm 

(Outdoor) 

N/S N/S N/S 

Rec. ITU-R 

M.687 and 

NTIA 

Special 

Publication 

95-32 

Max

agg

sign

can 

signifi

q

I ≤ –110 

dBm (CDMA 

2000 1X) 

N/S 1.25 MHz 

I ≤ –105 

dBm (CDMA 

2000 3X) 

N/S 3.75 MHz 

I ≤ –111 

dBm (TDCDMA) N/S 3.84 MHz 

Land Mobile 

(IMT 2000 

Mobile 

Stations) 

Below 3 

GHz 

I ≤ –105 

dBm 

(W-CDMA) 

N/S N/S 

N/S 

NTIA 

Special 

Publication 

01-46 

D

s
SWITCH 

Table 7-5(cont) 

Summary of IPC for Digital Channels in the Mobile Services 

7-11

Systems/ Interference Protection 

Services 

Frequency 

Bands 

CW/Noise Pulse/ 

Other 

Reference 

bandwidth

% 

Time 

Source 

Document 

I ≤ –94 dBm 

(CDMA 2000 

1X) 

N/S 1.25 MHz N/S 

I ≤ –90 dBm 

(CDMA 2000 

3X) 

N/S 3.75 MHz 

I ≤ –92 dBm 

(TD-CDMA) N/S 3.84 MHz 

Land Mobile 

(IMT 2000 

Mobile 

Stations) Below 3 GHz 

I ≤ –89 dBm 

(W-CDMA) N/S N/S 

N/S 

NTIA 

Special 

Publication 

01-46 

De

abo

I ≤ –114 dBm 

(CDMA 

2000 1X) 

N/S 1.25 MHz 

I ≤ –109 

dBm (CDMA 

2000 3X) 

N/S 3.75 MHz 

I ≤ –131 

dBm (UWC) N/S 0.03 MHz 

I ≤ –123 

dBm (UWC)* N/S 0.22 MHz 

Land Mobile 

(IMT 2000 

Base 

Stations) 

Below 3 

GHz 

I ≤ –115 

dBm (TDCDMA) N/S 3.84 MHz 

N/S 

NTIA 

Special 

Publication 

01-46. 

D

s
SWITCH 

Table 7-5(cont) 

Summary of IPC for Digital Channels in the Mobile Services 

7-12

Systems/ Interference Protection 

Services 

Frequency 

Bands 

CW/Noise Pulse/ 

Other 

Reference 

bandwidth

% 

Time 

Source 

Document 

I ≤ –98 dBm 

(CDMA 2000 

1X) 

N/S 1.25 MHz 

I ≤ –93 dBm 

(CDMA 2000 

3X) 

N/S 3.75 MHz 

I ≤ –115 

dBm 

(UWC) 

N/S 0.03MHz 

I ≤ –107 

dBm (UWC) N/S 0.22 MHz 

Land Mobile 

(IMT 2000 

Base 

Stations) 

Below 3 

GHz 

I ≤ –96 dBm 

(TD-CDMA) N/S 3.84 MHz 

N/S 

NTIA 

Special 

Publication 

01-46. 

De

abo

S/I ≥ 2 dB 

(A) S/I = 4 

dB (D) 

N/S N/S N/S 

Land Mobile N/S S/I ≥ 5 dB 

(A) S/I = 15 

dB (D) 

N/S N/S N/S 

NTIA TM 

 87-122 

Land Mobile N/S N/S S/I ≥ 18 dB N/S N/S 47 CFR 90.187 Interfe

a 

Land Mobile VHF N/S S/I ≥ 10 dB N/S N/S 47 CFR 80.773b Interfe
SWITCH 

Table 7-5(cont) 

Summary of IPC for Digital Channels in the Mobile Services 

7-13

Systems/ Interference Protection 

Services 

Frequency 

Bands 

CW/Noise Pulse/ 

Other 

Reference 

bandwidth

% 

Time 

Source 

Document 

C4FMI

(IMBE) VHF, UHF I N

C

+

≥16.5 

dB II N/S 12.5 kHz N/S TSB88-A Table A-1 

CQPSKIII

(IMBE) VHF, UHF I N

C

+

≥16.5 

dB II N/S 12.5 kHz N/S TSB88-A Table A-1 

π/4IV

DQPSK 

(IMBE) 

TDMA 

VHF, UHF I N

C

+

≥15.2 

dB II N/S 12.5 kHz N/S TSB88-A Table A-1 

EDACS®V

(IMBE) VHF, UHF I N

C

+

≥16.7 

dB VI N/S 12.5 kHz N/S TSB88-A Table A-1 

CVSD 

“XL”VII VHF, UHF I N

C

+

≥ 12 dB 

VIII N/S 25 kHz N/S TSB88-A Table A-1 

C4FMIX

(VSELP) VHF, UHF I N

C

+

≥17.4 

dB X N/S 12.5 kHz N/S TSB88-A Table A-1 

Valu

3.4. 

as

gover

th

protestated 

1). 

differin

in TS

Cellular 800, 900, 1800, 1900 C/I≥9 dB N/S N/S N/S Rec. ITU-R M.1073 

Digital LMS 1452-1492 pfd ≤ –150 W/m2/4 kHz N/S N/S N/S Rec. ITU-R M.1388 Rec. n

deve
SWITCH 

Table 7-5(cont) 

Summary of IPC for Digital Channels in the Mobile Services 

7-14

Frequency Interference Protection 

Bands 

CW/Noise Pulse/ 

Other 

Reference 

bandwidth

% 

Time 

Source 

Document 

Analog 

speech, 

12.5-25 kHz 

channels 

VHF, UHF C/I ≥ 10 dB N/S N/S N/S 

For 

an

sid

so

C/I ≥ 11 dB N/S N/S N/S 

For 

an

sid

soun

C/N 

π/4 QPSK, 

50 kHz 

channels, 3 x 

10-2 BER 

VHF, UHF 

C/I ≥ 17 dB N/S N/S N/S 

For 

an

sid

soun

GMSK, BT = 

0.3, 200 kHz 

channels 

VHF, UHF C/I ≥ 9 dB N/S N/S N/S 

Rec. ITU-R 

SM.851-1 

(provides 

additional 

IPC for 

non-cochannel 

operation) 

For 

an

sid

sou

Public 

Correspondence and 

Automatic 

Identification 

Systems 

VHF N/S I/S Values N/S N/S 

NTIA 

Report 00-

376 

Fu

requ

IPC 
SWITCH 

Table 7-5(cont) 

Summary of IPC for Digital Channels in the Mobile Services 

7-15

Systems/ Interference Protection 

Services 

Frequency 

Bands 

CW/Noise Pulse/ 

Other 

Reference 

bandwidth

% 

Time 

Source 

Document 

25 kHz/12.5 

kHz 

VHF Radios 

VHF N/S S/I Values N/S N/S 

NTIA 

Report 97-

343 

Fu

requ

IPC 

25 kHz Radios VHF N/S S/I Values N/S N/S 

NTIA 

Report 99-

363 

Fu

requ

IPC 

Public coast 

station VHF N/S C/I ≥ 12 dB N/S N/S 47 CFR 80.773a 

T

subse

allo

within 

the inc

AMS 17.975-137 MHz N/S D/U ≥ 14 dB N/S N/S 

ICAO 

Annex 10, 

Vol. 5, 

4.1.5.1, 

page 8 

Inte

dis

betw
SWITCH 

Table 7-5(cont) 

Summary of IPC for Digital Channels in the Mobile Services 

7-16

D= Digital; A=Analog * UWC refers to the IMT-2000 Radio Interface “UWC-136”. 

I C4FM/IMBE/VSELP = A 4-ary FM modulation technique that produces the same phase shift as a com

modulation technique. Consequently, the same receiver may receive either modulation. IMBE-The aImproved Multi Band Excitation, the project 25 standard vocoder per ANSI/TIA/EIA-102.BABA. “A vo

based on Sinusoidal Transform Coding (analog to digital voice conversion).” 

II BER = 2% III CQPSK: = The acronym for Compatible, Quadrature Phase Shift Key (QPSK) AM. An emitter that us

modulation that allows compatibility with a frequency discriminator detection receiver. 

IV π/4 DQPSK = The acronym for “Differential Quadrature Phase Shift Keying”, “Quadrature” indicates 

of the modulation is a multiple of 90 degrees. Differential indicates that consecutive symbols are phadegrees (π/4) from each other. 

V EDACS = Enhanced Digital Access Communication System VI BER = 2.8 % VII CVSD = Continuously variable slope delta modulation: A type of delta modulation in which the size o

approximated signal is progressively increased or decreased as required to make the approximated 

the input analog wave. 

VIII BER = 3% IX VSELP -Vector-Sum-Excited Linear Prediction X BER = 1.4% 
SWITCH 

Table 7-6 

Summary of IPC for Digital Channels in the MSS 

7-17

Services /Systems Frequency Interference Protection 

Bands CW/ 

Noise-like 

Pulse/ 

Other 

Reference 

Bandwidth 

% Time Source 

Docume

Iagg/NBERi ≤

 –6.2 dB 

Iagg/NBER ≤

 –7 dB 

GSO/MSS, 

GSO/AMS(R)S 1-3 GHz 

Ise/NBER ≤

 –12.2 dB 

N/S N/S N/S 

Recs. ITU

R M.118

M.1234 

GSO/AMS(R)S 

1545-1555 

and 1646.5- 

1656.5 MHz 

Iagg/NBER ≤

 –7 dB, 

Ise/NBER ≤

 –12.2 dB 

N/S N/S N/S Rec. ITU-

M.1234 

Iagg ≤

–142.1 dBW 

Ise, NGSO/MSSii ≤

–146.2 dBW 

NGSO/MSS 

downlink 

137-138 

MHz 

Ise, terrestrial iii ≤

–147.3 dBW 

N/S 44 kHz 20 

Recs. ITU

R M.123

M.1232 
SWITCH 

Table 7-6(cont) 

Summary of IPC for Digital Channels in MSS 

7-18

Services /Systems Frequency Interference Protection 

Bands 

CW/ 

Noise-like 

Pulse/ 

Other 

Reference 

Bandwidth 

% Time Source 

Docume

Iagg ≤–133.4 

dBW 0.25 

Ise, NGSO/MSS ≤

–133.8 dBW 0.0625 

Ise, terrestrial ≤

–133.8 dBW 

N/S 44 kHz 

0.125 

Iagg ≤

–155.3 dBW 

Ise, NGSO/MSS ≤

–159.9 dBW 

Ise, terrestrial ≤

–160.6 dBW 

20 

Iagg ≤

–144. 5 dBW 0.25 Ise, NGSO/MSS ≤

–144.7 dBW 0.0625 

Ise, terrestrial ≤

–144.8 dBW 

N/S 19.2 kHz 

0.125 

Iagg ≤

–134.5 dBW 

Ise, NGSO/MSS ≤

–138.5 dBW 

Ise, terrestrial ≤

–141.5 dBW 

20 

NGSO/MSS 

downlink 

137-138 

MHz 

Iagg ≤

–128.5 dBW 

N/S 885 kHz 

0.25 

Recs. ITU

R M.123

M.1232 
SWITCH 

Table 7-6(cont) 

Summary of IPC for Digital Channels in MSS 

7-19

Services /Systems Frequency Interference Protection 

Bands 

CW/ 

Noise-like 

Pulse/ 

Other 

Reference 

Bandwidth 

% Time Source 

Documen

Ise, NGSO/MSS ≤

–129 dBW 0.0625 NGSO/MSS 

downlink 

137-138 

MHz Ise, terrestrial ≤

–129.5 dBW 

N/S 885 kHz 

0.125 

Recs. ITU

R M.1231

M.1232 

Max spfd ≤

–198.6 

dBW/(m2·Hz) 

N/A 

COSPAS/SARSAT Max pfd = 

–185.8 

dBW/m2

19 Hz 

Max spfd = 

–200.8 

dBW/(m2·Hz) 

N/A 

COSPAS/SARSAT 

406-406.1 

MHz 

Max pfd = 

–176.6 

dBW/m2

N/S 

40 Hz 

N/S Rec. ITU-R M.1478 

i. Iagg: aggregate interfering signal power; NBER: total noise power giving rise to the objective BER; Is

interfering signal power. 

ii. Ise, NGSO/MSS: single-entry interfering signal from other NGSO/MSS systems. iii. Ise, terrestrial: single-entry interfering signal from terrestrial systems. iv. Victim system A: OQPSK/FDMA transmission to gateway, 15 dBi horn antenna, elevation angle eq

20 ̊. 

v. Victim system B: BPSK/FDMA transmission to subscriber, 0 dBi monopole antenna with cos2 radia

angle equal to or greater than 20 ̊. 

vi. Victim system C: Minimum shift keying/direct sequence (MSK/DS)-SSMA transmission to gateway, 

elevation angle equal to or greater than 20 ̊. 

vii. Interfering system A: broadband system using adjacent frequency bands. viii. Interfering system B: spurious emission from narrow-band system below 406 MHz. 
SWITCH 

7-20

REFERENCES

1

 NTIA Manual, Annex I, (September 2003). 

2

 JSC-CR-96-016B, 1998, JSMSW Interference Analysis Algorithms Consulting Report, 

Department of Defense, Joint Spectrum Center, Annapolis, Maryland (April 1998). 

3

 CCIR Study Programme 18B/1, Report 826-1, “Examples of Band by Employing 

Spread-Spectrum Techniques,” Reports of the CCIR, 1990 Annex to Volume 1, Printed 

in Geneva, Switzerland (1990). 

4

 NTIA Special Publication 95-32, Spectrum Reallocation Final Report, Response to 

Title VI - Omnibus Budget Reconciliation Act of 1993 (February 1995). 

5

 ITU-R Rec. M.687-2, 02, International Mobile Telecommunications-2000, Part 2 (1997) 

6

 NTIA Special Publication 01-46, The Potential for Accommodating Third Generation 

Mobile Systems in the 1710-1850 MHz Band: Federal Operations, Relocation Costs 

and Operational Impacts, Final Report (March 2001). 

7

 NTIA Technical Memorandum 87-122, Assessment of Digital Radio Voice Protection 

for Government Land-Mobile Use (July 1987). 

8

 TSB-88A, Wireless Communications Systems - Performance in Noise and 

Interference-Limited Situations - Recommended Methods for Technology-Independent 

Modeling, Simulation, and Verification, Telecommunications Industry Association, 

Arlington, Virginia (1999). 

9

 Rec. ITU-R M.1073-1, Digital Cellular Land Mobile Telecommunication Systems 

(1997). 

10 Rec. ITU-R M.1388, Threshold Levels to Determine the Need to Coordinate Between 

Space Stations in the Broadcasting-Satellite Service (Sound) and Particular Systems in 

the Land Mobile Service in the Band 1452-1492 MHz (1999). 

11 Rec. ITU-R SM.851-1, Sharing Between the Broadcasting Service and the Fixed 

and/or Mobile Services in the VHF and UHF Bands (1993). 

12 NTIA Report 99-362, Evaluation of Marine VHF Radios: Performance in the 

Savannah, Ga., and New Orleans, La., Port Areas (April 1999). 

13 NTIA Report 00-376, Electromagnetic Compatibility Between Marine Automatic 

Identification and Public Correspondence Systems in the Maritime Mobile VHF Band

(August 2000). 
SWITCH 

7-21

14 NTIA Report 00-343, Assessment of Compatibility Between 25 and 12.5 kHz 

Channelized Marine VHF Radios (August 1997). 

15 NTIA Report 99-363, Evaluation of Marine VHF Radios: Compliance to IEC Receiver 

Standards (April 1999); IEC 1097-7, Global Maritime Distress and Safety System 

(GMDSS): Shipborne VHF radiotelephone transmitter and receiver Operational and 

performance requirements Methods of testing and required test results, International 

Electrotechnical Commission (1996). 

16 ICAO Annex 10 Volume V Chapter 4 Utilization of Frequencies Above 30 MHz, 

International Civil Aviation Organization (July 1996). 

17 Rec. ITU-R M.547, Noise objectives in the hypothetical reference circuit for systems 

in the maritime mobile-satellite service (1978). 

18 Rec. ITU-R M.552, Quality objectives for 50-baud start-stop telegraph transmission in 

the maritime mobile-satellite service (1978).

19 Rec. ITU-R M.1229, Performance objectives for the digital aeronautical mobilesatellite service (AMSS) channels operating in the bands 1 525 to 1 559 MHz and 1 

626.5 to 1 660.5 MHz not forming part of the ISDN (1997). 

20 Rec. ITU-R M.1183, Permissible levels of interference in a digital channel of a 

geostationary network in mobile-satellite service in 1-3 GHz caused by other networks 

of this service and fixed-satellite service (1995). 

21 Rec. ITU-R M.1037, Bit error performance objectives for aeronautical mobile-satellite 

(R) service (AMS(R)S) radio link (1994). 

22 Rec. ITU-R M.1234, Permissible level of interference in a digital channel of a 

geostationary satellite network in the aeronautical mobile-satellite (R) service 

(AMS(R)S) in the bands 1 545 to 1 555 MHz and 1 646.5 to 1 656.5 MHz and its 

associated feeder links caused by other networks of this service and the fixed-satellite 

service (1997). 

23 Rec. ITU-R M.1476, Performance objectives for narrow-band digital channels using 

geostationary satellites to serve transportable and mobile Earth stations in the 1-3 GHz 

range forming part of the integrated services digital network (2000). 

24 Rec. ITU-R M.1181, Minimum performance objectives for narrow-band digital 

channels using geostationary satellites to serve transportable and vehicular mobile 

earth stations in the 1-3 GHz range, not forming part of the ISDN (1995). 
SWITCH 

7-22

25 Rec. ITU-R M.1230, Performance objectives for space-to-Earth links operating in the 

mobile-satellite service with non-geostationary satellites in the 137-138 MHz band

(1997). 

26 Rec. ITU-R M.1231, Interference criteria for space-to-Earth links operating in the 

mobile-satellite service with non-geostationary satellites in the 137-138 MHz band

(1997). 

27 Rec. ITU-R M.1232, Sharing criteria for space-to-Earth links operating in the mobilesatellite service with non-geostationary satellites in the 137-138 MHz band (1997). 

28 Rec. ITU-R M.1478, Protection criteria for Cospas-Sarsat search and rescue 

processors in the band 406-406.1 MHz (2004).
SWITCH 

8-1

SECTION 8 

SCIENCE SERVICES 

8.1 INTRODUCTION 

Science services include the space research service, inter-satellite 

service, space operations service, meteorological aids service, Earth explorationsatellite (EES) and meteorological-satellite (METSAT) services, and radio 

astronomy service. Space research services include deep space, near earth and 

data relay satellite (DRS) satellite services. EES and METSAT services include 

command and data, space-to-Earth data, data dissemination and direct readout, 

and passive and active sensors. Various ITU-R Recommendations specify IPC 

for these services for noise-like or CW-type interfering signals in a specified 

reference bandwidth. No IPC were found for pulse or impulse type interfering 

signals. 

8.2 SPACE RESEARCH SERVICE 

The space research service supports diverse scientific and technology 

programs that provide information about the solar system, the nature and 

structure of the universe, and the origin and fate of matter. The systems include 

manned and unmanned spacecraft, communication networks on the surface of 

the Earth, and spacecraft in various orbits or trajectories. Spacecraft further than 

2 X 106

 km from the Earth are referred to as “deep space” spacecraft. 

The phases of space research missions potentially having different 

requirements include pre-launch checkout, launch operations, transfer 

operations, on-orbit operations and landing operations. Communication links for 

command, telemetry and tracking data are variously required between co-orbiting 

spacecraft and between the spacecraft and earth stations either directly or 

through Data Relay Satellites (DRS). 

Phase-lock loops are extensively used in space research communication 

systems. Because a strong interfering signal component can cause the receiver 

to lock to the interfering signal rather than the desired signal, narrow reference 

bandwidths are specified in the IPC. Protection criteria for space research 

services are given in Recs. ITU-R SA.363, SA.609, SA.1155, SA.1157, and 

SA.1396.1

8.2.1 Deep-Space Research 

IPC for deep-space research systems are given in Rec. ITU-R SA.1157. 

There are four receiver subsystems in deep-space earth stations that are 

particularly sensitive to interfering signals: maser pre-amplifier, carrier tracking 
SWITCH 

8-2

loop, telemetering subsystem and ranging subsystem. To ensure proper 

operation, each of the four subsystems must be protected against interference. 

The IPC specifies the amount of interfering signal power that will result in a 

maximum acceptable degradation of performance. 

The gain of maser pre-amplifiers typically used in deep space earth 

station receivers is reduced by strong interfering signals, which also results in 

non-linear operation. The response of the carrier tracking loop is an increase in 

phase error and jitter that can cause loss of lock. The degradation of telemetry 

bit error performance and ranging accuracy as a result of interfering signals can 

be expressed in terms of a reduction in signal-to-noise ratio. Table 8-1 

summarizes the maximum acceptable performance degradation. 

Table 8-1 

Maximum Acceptable Degradation of Receiver Subsystems 

Receiving Subsystem Maximum Acceptable Degradation 

Maser pre-amplifier 

Carrier tracking 

1 dB gain compression 

10o loop static phase error or peak 

phase jitter 

Telemetry 

1 dB equivalent reduction in symbol 

energy to noise spectral density 

increase (ΔE/No = –1 dB) 

Ranging 

1 dB equivalent reduction in symbol 

energy to noise spectral density 

increase (ΔE/No = –1 dB) 

The amount of interfering signal power that can cause the degradation 

shown in Table 8-1 is given in Annex 2 of Rec. ITU-R SA.1157 for CW and noiselike interfering signals. Table 8-2 shows the maximum allowable interference-tocarrier ratio (I/C), interference-to-signal ratio (I/S) or interference-to-noise ratio 

(I/N) that corresponds to maximum acceptable degradation of carrier tracking, 

telemetry and ranging subsystems. From Table 8-2, the maximum allowable CW 

interfering signal power is dictated by the carrier tracking loop. For carrier 

tracking, the maximum permissible power of noise-like interfering signals have 

been calculated from maximum I/C, receiver noise spectral density, carrier 

tracking loop bandwidth and minimum C/N ratio required for carrier tracking. 

The resulting IPC are summarized in Table 8-3. 
SWITCH 

8-3

Table 8-2 

Basis for IPC for CW and Noise-like Interfering Signals 

at Deep Space Earth Stations 

Subsystem (criterion) Interfering Signal 

Type 

IPC 

Carrier tracking 

(10o added peak phase 

jitter) 

CW 

Noise-like 

I/C ≤ – 15 dB 

I/N ≤ + 2.3 dB 

Telemetry 

(1 dB reduction in E/No

from interfering signal in 

carrier tracking loop) 

CW I/C ≤ – 1.5 dB 

Telemetry 

(1 dB reduction in E/No

from interfering signal in 

telemetry detection 

bandwidth) 

CW 

Noise-like 

I/S ≤ –11 dB 

I/N ≤ – 5.9 dB 

Ranging 

(1 dB reduction in E/No

from interfering signal in 

carrier tracking loop) 

CW I/C ≤ – 5 dB 

Ranging 

(1 dB reduction in E/No

from interfering signal in 

range estimator 

bandwidth) 

CW 

Noise-like 

I/S ≤ – 7.1 dB 

I/N ≤ – 5.9 dB 

The IPC for deep-space station receivers are based on an I/N of 0 dB. 

Unlike for the space-to-Earth links, substantial power margins are available on 

the Earth-to-space links. 

8.2.2 Near Earth Space Research 

The permissible I/N ratio in a near-earth space research communication 

link is determined by the portion of the link margin allocated to interfering signals. 

Typical link margins range from 3 to 6 dB for frequencies below 10 GHz and 

larger margins are used at higher frequencies. Interference can be harmful if the 

link power margin is decreased by more than 1 dB. This corresponds to an I/N of 

–6 dB. The reference bandwidth for the IPC depends upon the smallest 

bandwidth likely to be employed. For manned space missions, a loss of more 

than 5 minutes of communication during critical periods of the mission would 

seriously affect the mission. To prevent interference for longer than 5 minutes 

per day, it is necessary not only to consider the worst hour in the year, but the 
SWITCH 

8-4

worst 5 minutes within that hour. This corresponds to 0.001% of the time for 

manned space missions, whereas, for unmanned space missions up to 0.1% of 

outage can be tolerated. 

In the 1-20 GHz range, the system noise temperature of receiving earth 

stations is typically as low as 70 K. Below about 1 GHz, cosmic noise increases 

the operating noise temperature of the system at a rate of about 20 dB per 

decade of decreasing frequency. The system noise temperature of a permissible 

space-station receiver is usually 600 K or more, partly due to the fact that the 

spacecraft antenna points at the Earth (290 K). The resulting IPC for near-earth 

research are given in Rec. ITU-R SA.609 and summarized in Table 8-3. 

8.2.3 Data Relay Satellites 

Data relay satellites operate in the space research, space operation, Earth 

exploration-satellite (EES) and the fixed-satellite (FSS) services. A link margin 

reduction of 0.4 dB has been used as a basis for the IPC. This corresponds to 

an I/N within the reference bandwidth of –10 dB. The IPC for data relay satellite 

systems are given in Rec. ITU-R SA.1155, and summarized in Table 8-3. 

8.2.4 Telecommunication Links in the 37-40 GHz Bands 

The frequency bands 37-38 GHz and 40-40.5 GHz have been allocated to 

the space research service on a primary basis worldwide. These bands are 

intended to be used for high-rate digital data transfer of telemetry, voice, and 

video between the Earth and other planetary bodies such as the Moon and Mars 

to support manned exploration. Further, the 37-38 GHz band is to be used for 

high-rate data transfer from an earth-orbiting S-VLBI station. Data rates of the 

order of 100 Mbits/s from planetary ranges, 500 Mbits/s for lunar ranges and 

1000 Mbits/s from S-VLBI station to earth are expected. 

For space-to-Earth links, typical link power margins are 2 to 4 dB. 

Therefore, during desired signal fading, interference can be severe if the link 

margin is lowered by more than 1 dB. This corresponds to an I/N ratio of about 

-6 dB. For Earth-to-space links, which are not power limited, up to 3 dB 

degradation may be tolerated (I/N of 0 dB). The reference bandwidths for earthstation and space-station receivers are 1 Hz and 20 Hz respectively. The 

percentage of time during which these thresholds may be exceeded are 0.001% 

of time for manned missions and 0.1% of time for unmanned missions. 

In the 37-38 GHz region, the IPC are based on a 60 K system noise 

temperature for receiving earth stations. In the 40-40.5 GHz range, the IPC for 

space research space station are derived from a noise temperature of 200 K and 

an I/N ratio of 0 dB. The IPC for space research service in the 37-40 GHz range 

are given in Rec. ITU-R SA.1396 and are summarized in Table 8-3. 
SWITCH 

8-5

8.3 SPACE OPERATION SERVICE 

The space operation service is a radiocommunication service concerned 

exclusively with the operation of spacecraft, in particular tracking, telemetry and 

telecommand. These functions are normally provided within the frequency 

allocations for the services in which the space station is operating. The preferred 

frequency bands for space operations lie approximately between 1 and 8 GHz. 

Lower frequencies are sometimes used for spacecraft that do not require high 

precision tracking. Frequencies above 10 GHz are suitable for space operation 

services during the re-entry of spacecraft into the atmosphere of the Earth. 

The reference bandwidth is based on phase-locked loop receivers having 

equivalent noise bandwidths of between a few hundred Hz and a few kilohertz. A 

value of 1 kHz has been adopted for the reference bandwidth. Generally, the 

percentage of time during which space operation links can tolerate interfering 

signal power above the protection level is fixed at 1% per day, approximately 

equivalent to 15 minutes per day. However, interference lasting for 15 

consecutive minutes may be intolerable during critical stages. 

Above 1 GHz, the total noise temperature of earth stations is 100 K. The 

IPC are based on that noise temperature and an I/N of –5 dB. Since the power 

of earth station transmitters can generally be increased within limits imposed by 

the Radio Regulations on-board receivers do not always operate at maximum 

sensitivity. The protection of space station receivers is therefore expressed in 

terms of protection ratios and the IPC are based on an S/I ratio of 20 dB. IPC for 

space operation systems are given in Rec. ITU-R SA.363 and are summarized in 

Table 8-3. 

8.4 METEOROLOGICAL AIDS 

The term MetAids is used to describe a variety of meteorological 

equipment, such as, radiosondes, dropsondes, rocketsondes and weather 

radars. IPC for weather radars are discussed separately in Section 5 due to their 

similarity to radiodetermination service radars. Other MetAids are flown 

worldwide for the collection of upper atmosphere meteorological data for weather 

forecasts, ozone monitoring, and other applications. 

IPC for MetAids are based on the link margin at the maximum slant range. 

The first level of interfering signal power is the level associated with loss of 

receiver lock, which may be exceeded only for 0.02% of time. The second level 

of interfering signal power is the level at which loss of data will occur. The 

percentage of time for this occurrence may be obtained from the user’s data 

availability objectives, typically 1.25% of time for radiosondes and 0.03% for 

dropsondes. The third interfering signal level will be the long-term level, at 20% 

of the time, which may result in data loss during desired signal fading. The IPC 

and underlying calculation methodology are given in Rec. ITU-R SA.1263.2
SWITCH 

8-6

8.5 EARTH EXPLORATION-SATELLITE AND METEOROLOGICAL 

SATELLITE SERVICES 

Systems in earth exploration-satellite service (EES) and meteorological 

satellite service (METSAT) utilize transmission systems having various Earth-tospace, space-to-space, and space-to-Earth links. These services support data 

collection, data dissemination, interrogation of data collection platforms, passive 

sensing, active sensing, direct data readout and recorded data acquisition. The 

methodology for determining IPC is given in Rec. ITU-R SA.1022.3 

8.5.1 Space-to-Earth Data Transmission Systems Using Low-Earth Orbit 

Using the performance criteria for space-to-Earth data transmission 

systems given in Rec. ITU-R SA.1025 and the methodology given in Rec. ITU-R 

SA.1022, IPC have been developed for METSAT and EES in different bands. 4

For METSAT service in the 137-138 MHz band, the automatic picture 

transmission (APT) system uses analog modulation with a bandwidth of 50 kHz 

and is planned to be phased out in 2005. Its replacement is the low resolution 

picture transmission (LRPT) system which uses digital modulation with a nominal 

data rate of 72 kbit/s. Two types of earth stations are used in this band, one with 

an unsteered low gain antenna for reception of local data and the other with a 

steerable medium gain antenna for reception of regional data. 

For METSAT service in the 400.15-401 MHz band, data from spacecraft 

sensors is multiplexed into a data stream at a rate of 88.75 kb/s. The typical 

earth stations are mobile with 0 dBi antenna gain. 

For METSAT service in the 1670-1710 MHz band and EES in the 1690-

1710 MHz band, the high resolution picture transmission (HRPT) system and the 

command and data acquisition system (CDA) use small and large earth stations 

respectively. For the large station, a 2.667 Mbit/s data rate is used and for the 

small station a data rate of 0.667 Mbit/s is used, and higher data rates are 

planned. 

In the 7450-7550 MHz a global recorded data (GRD) system expected to 

be implemented around 2005. IPC are based on the system design parameters. 

The EES service at 8025-8400 MHz uses two systems. For “System A,” a 

major data acquisition facility receives stored data and the low cost facility 

receives real time regional data. For “System B,” a major data acquisition facility 

is also used to receive wideband (420 Mbit/s) direct data readout. 
SWITCH 

8-7

The IPC for space-to-Earth data transmission systems operating in 

METSAT and EES services using satellites in low-Earth orbits are given in Rec. 

ITU-R SA.1026 and are summarized in Table 8-3.5

8.5.2 Data Dissemination and Direct Data Readout Systems Using 

Geostationary Satellites 

For direct readout systems, all of the interfering signals enter the receiving 

earth station directly. (The data originates at the satellite and none is received 

via satellite retransmission.) Dissemination of high-resolution processed data 

and lower resolution weather facsimile (WEFAX) data is affected by the 

interfering signal power received at the station via the satellite as well as directly 

by the earth station in the 1670-1710 MHz band. These data are up-linked to the 

satellite in the 2025-2110 MHz band, and relayed, along with interfering signals 

entering the satellite in the same band, to the earth station receivers via fixed 

gain satellite transponders. 

For links in the EES and MetSat services using geostationary orbits, the 

performance objectives are given in Rec. ITU-R SA.1159.6 IPC have been 

determined using the methodology given in Rec. ITU-R SA.1022. The IPC for 

data dissemination and direct data readout systems in the EES and METSAT 

services are given in Rec. ITU-R SA.1160-2 and are summarized in Table 8-3.7 

8.5.3 Service Links in Data Collection Systems 

Systems for data collection and platform location in the EES and METSAT 

services collect data for users needing information from a variety of sources, 

which may be located anywhere in the world. Two types of orbits are used: low 

earth orbits (LEO) and geostationary-satellite orbit (GSO). The GSO systems 

provide data with a delivery delay of typically 5 minutes, but do not cover the 

polar region. The LEO systems offer worldwide coverage as well as the platform 

location with a delivery delay of up to 1 to 3 hours. 

Telecommunication requirements and performance objectives for service 

links in data collection and platform location are given in Rec. ITU-R SA.1162.8

 

Using the methodology described in Rec. ITU-R SA.1022, the IPC are given in 

Rec. ITU-R SA.1163 and are summarized in Table 8-3.9

8.5.4 Command and Data Transmission System 

For all command and data transmission systems in bands other than 

those treated in Recs. SA.1026, SA.1160 and SA.1163, the IPC for earth 

receiving sites and for near-earth spacecraft are given in Rec. ITU-R SA.514 and 

are summarized in Table 8-3.10
SWITCH 

8-8

8.5.5 Satellite Passive Remote Sensing 

Passive sensing is the measurement of natural emissions from the Earth 

and its atmosphere. Certain frequency bands coinciding with these emissions 

have been allocated for spaceborne passive microwave remote sensing. These 

include some absorption bands for atmospheric gases (O2 and H2O). 

Measurements in the absorption band are extremely vulnerable to interference 

because there is very little possibility to detect and reject data that are 

contaminated by interference. The use of contaminated data in numerical 

weather prediction (NWP) would have an adverse effect on the quality of weather 

forecasting. 

The sensitivities of radiometric passive sensors are generally expressed 

as a temperature differential, ΔTe. The minimum discernable power change is 

given by: 

ΔP = k ΔTe B Watts (8-3) 

Where, k is the Boltzmann’s constant and B is the receiver bandwidth in 

Hz. Harmful interference to passive sensors may occur when unwanted signal 

levels exceed 20% of ΔP, which is a basis for the IPC. Measurement 

sensitivities suitable for passive sensing of land, oceans and atmosphere within 

their allocated bands are given in Rec. ITU-R SA.1028.11 The permissible 

interference levels and reference bandwidths are given in Rec. ITU-R SA.1029, 

and are summarized in Table 8-3.12

8.5.6 Spaceborne Active Microwave Remote Sensors 

The performance requirements for active sensors can be stated in terms 

of measurement precision and availability. The performance criteria for various 

active sensors are as follows. 

Synthetic Aperture Radars (SAR): near 400 MHz, a performance criterion 

for SARs is to collect SAR imagery with a minimum reflectivity of –39 dB. 

Altimeters: near 5.3 GHz, 13-14 GHz and 35.5-36.0 GHz, a performance 

criterion for altimeters is to measure the sea level with a precision of at least 3 

cm. An increase in height noise of 0.1 cm, corresponding to 4% degradation in 

height noise in the presence of a systematic height noise of 2-2.4 cm, would be 

consistent with mission objectives. 

Scatterometers: near 5.3 GHz, 13-14 GHz and 35.5-36.0 GHz, the 

performance criterion for scatterometers is measurement of wind speeds greater 

than or equal to 3 m/s. 
SWITCH 

8-9

Precipitation radars: the science requirement for precipitation radars is to 

achieve, after data processing, measurement of rain rates equal to or greater 

than 0.7 mm/h in the 13-14 GHz band and 0.15 mm/h in the 35.5-36.0 GHz band. 

An increase in measurable rain rate to 0.75 mm/h in the 13-14 GHz band and 0.2 

mm/h in the 35.5-36.0 GHz band would not materially affect the data and would 

be acceptable as a basis for IPC. 

Cloud profiling radars: at 35.5-36.0 GHz and 94-94.1 GHz, the 

performance criterion for cloud profiling radars is to measure the reflectivity 

profile for all clouds within the field of view with a minimum reflectivity of 

-30 dBZ. A degradation of minimum measurable reflectivity (Zmin) by less than 

10% due to interference would be consistent with mission objectives. 

IPC for active sensors and their technical bases are given in Rec. ITU-R 

SA.1166-2.13 The IPC are given in Table 8-3. 

8.6 RADIO ASTRONOMY 

Radio astronomical measurements are made from the Earth’s surface 

from 2 MHz to 800 GHz and from space platforms at frequencies which extend 

down to lower than 10 kHz. 

The sensitivity of the receivers used for radio astronomy greatly exceeds 

the sensitivity of typical communications and radar equipment. The sensitivity is 

defined by the smallest power level change ΔP at the input which can be 

detected and measured. The interfering signal threshold levels are defined as 

the interfering signal level which introduces an error of 10% in the measurement 

of ΔP. The IPC are based on assumed integration time of 2000 seconds and 0 

dBi antenna gain toward the interferer. Integration times actually used in 

astronomical observations cover a wide range of values. The IPC for radio 

astronomical measurements are given in Rec. ITU-R RA.769.14

Interfering signals received by widely-spaced antennas used for Very 

Long Baseline Interferometry (VLBI) will undergo different relative time delays 

before they are recombined. Compared to a single antenna radio telescope, the 

interferometer has a greater degree of immunity, which increases with the size of 

the array in wavelengths. In VLBI, the separation of antennas is such that the 

chance of occurrence of correlated interfering signals is very small. The tolerable 

interfering signal level is determined by the requirement that the power level of 

the interfering signals should be less than 1% of the receiver noise power to 

prevent serious errors. Large interferometers and arrays are generally used to 

study discrete high brightness sources, with angular dimensions no more than a 

few tenths of a second of arc for VLBI. The IPC for VLBI are given in Rec. ITU-R 

RA.769. 
SWITCH 

8-10

8.7 SUMMARY 

 

Table 8-3 provides a summary of the IPC for the science services.
Table 8-3 

Summary of Interference protection criteria for science services 

8-11

Interference Protectioni Services 

Systems 

Frequency 

Bands CW & 

Noiselike 

Pulse Other 

Reference 

BW 

% 

Time 

Source 

Document 

SPACE RESEARCH SERVICE 

2.3 GHz I ≤ –222 dBW N/S 8.4 GHz I ≤ –220 dBW N/S 

13.0 GHz I ≤ –220 dBW N/S 

Deep Space 

Research 

Earth Stations 32.0 GHz I ≤ –216 dBW N/S 

1 Hz 0.001 Rec. ITU-R 

SA.1157 

2.1 GHz I ≤ –191 dBW N/S 7.2 GHz I ≤ –189 dBW N/S 

17.0 GHz I ≤ –186 dBW N/S 

Deep Space 

Research 

Space Stations 34.5 GHz I ≤ –184 dBW N/S 

20 Hz 0.001 Rec. ITU-R SA.1157 

1-20 GHz I ≤ –216 dBW N/S Near Earth 

Research 

Earth Stations Below 1 GHz See comments N/S 1 Hz 

0.001 

Manned 

0.1 Unmanned 

Rec. ITU-R 

SA.609I 

Near Earth 

Research 

 Space Stations 

100 MHz30 GHz I ≤ –177 dBW N/S 1 kHz 0.1 Rec. ITU-R SA.609 

I Unless otherwise indicated, IPC represents maximum allowable power density at the receiver termina
Table 8-3(cont) 

Summary of Interference protection criteria for science services 

8-12

Services Interference Protection Systems 

Frequency 

Bands CW & 

Noiselike 

Pulse Other 

Reference 

BW 

% 

Time 

Sourc

Docume

2.025-2.110 GHz I ≤ –181 dBW N/S 

13.5-13.8 GHz I ≤ –178 dBW N/S 

Data Relay 

Satellite 

Forward 

Inter-Orbit Link 

User 

Spacecraft 

22.55-23.55 GHz I ≤ –178 dBW N/S 

1 kHz 0.1 Rec. ITU

SA.115

2.200-2.290 GHz I ≤ –181 dBW N/S 14.89-15.18 GHz I ≤ –178 dBW N/S 

Data Relay 

Satellite Return 

Inter-Orbit-Link 25.25-27.5 GHz I ≤ –178 dBW N/S 

1 kHz 0.1 Rec. ITU

SA.115

Data Relay 14.35-15.35 GHz I ≤ –167 dBW N/S 

Satellite 

Forward 

Feeder Link 

27.0-30.0 GHz I ≤ –169 dBW N/S 1 kHz 0.1 Rec. ITU

SA.115

10.81-10.86 GHz I ≤ –176 dBW N/S 

13.4-14.05 GHz I ≤ –176 dBW N/S 

Data Relay 

Satellite Return 

Feeder Link 17.2-21.2 GHz I ≤ –172 dBW N/S 

1 kHz 0.1 Rec. ITU

SA.115

Space 

Research 

Earth Station 

37-38 GHz I ≤ –217 dBW N/S 1 Hz 

0.1 Unmanned 

0.001 

Manned 

Rec. ITU

SA.139

Space 

Research 

Space Station

40-40.5 GHz I ≤ –193 dBW N/S 20 Hz 0.1 Rec. ITU

SA 139
Table 8-3(cont) 

Summary of Interference protection criteria for science services 

8-13

Services Interference Protection Systems 

Frequency 

Bands CW & Noiselike Pulse 

Other 

Reference 

BW 

% 

Time 

Source 

Documen

SPACE OPERATIONS SERVICE 

1-30 GHz I ≤ -184 dBW N/S 

Earth Station 0.1-1 GHz See Comments N/S 1 kHz 1 Rec. ITU-R SA.1263 

Space Station 100 MHz-30 GHz S/I ≥ 20 dB N/S 1 kHz 1 Rec. ITU-R SA.363-5 

METEOROLOGICAL AIDS 

1669.4-1700 

MHz I ≤ –135.3 dBW N/S 0.02 

1669.4-1700 

MHz I ≤ –148.5 dBW N/S 1.25 

Radio Direction 

Finding 

Radiosonde 1669.4-1700 

MHz I ≤ –149.4 dBW N/S 

1.3 MHz 

20 

Rec. ITU-R 

SA.1263 

400.15-406 

MHz I ≤ –140.6 dBW N/S 0.02 

400.15-406 

MHz I ≤ –149.6 dBW N/S 1.25 

NAVAID 

Radiosonde 

Directional 

Receiver 

Antenna 400.15-406 MHz I ≤ –154.9 dBW N/S 

300 kHz 

20 

Rec. ITU-R 

SA.1263 

400.15-406 

MHz I ≤ –141.9 dBW N/S 0.02 

400.15-406 

MHz I ≤ –154.4 dBW N/S 1.25 

OmniDirectional 

Receiver 

Antenna 400.15-406 

MHz I ≤ –156.1 dBW N/S 

300 kHz 

20 

Rec. ITU-R 

SA.1263 
Table 8-3(cont) 

Summary of Interference protection criteria for science services 

8-14

Services Interference Protection Systems 

Frequency 

Bands CW & 

Noiselike 

Pulse Other 

Reference 

BW 

% 

Time 

Sourc

Docume

400.15-406 

MHz 

I ≤ –153.3 

dBW N/S 0.02 

400.15-406 

MHz 

I ≤ –161.5 

dBW N/S 0.03 Airborne Dropsonde 

400.15-406 

MHz 

I ≤ –167.1 

dBW N/S 

20 kHz 

20 

Rec. ITU

SA.126

400.15-406 

MHz 

I ≤–124.9 

dBW N/S 0.02 

400.15-406 

MHz 

I ≤ –125.5 

dBW Rocketsonde N/S 0.03 

400.15-406 

MHz 

I ≤ –134.7 

dBW N/S 

3 MHz 

20 

Rec. ITU

SA.126

EARTH EXPLORATION AND METEOROLOGICAL SATELLITE SERVICES (EES/M

1-10 GHz I ≤ –154 dBW N/S Command Data 

Earth Station Below 1 GHz See Comments N/S 1 MHz 1 Rec. ITU

SA.514 

0.3-10 GHz I ≤ –161 dBW Command Data N/S Near Earth 

Spacecraft Below 0.3 GHz See comments N/S 1 kHz 0.1 Rec. ITU

SA.514 
Table 8-3(cont) 

Summary of Interference protection criteria for science services 

8-15

Services Interference Protection Systems 

Frequency 

Bands CW & 

Noiselike 

Pulse Other 

Reference 

BW 

% 

Time 

Sourc

Docume

137-138 MHz I ≤ –151 dBW N/S 20 137-138 MHz I ≤ –145 dBW N/S 50 kHz 0.025 137-138 MHz I ≤ –141 dBW N/S 20 137-138 MHz I ≤ –133 dBW N/S 0.25 137-138 MHz I ≤ –142 dBW N/S 20 137-138 MHz I ≤ –136 dBW N/S 

150 kHz 

0.025 

400.15-401.00 

MHz 

I ≤ –158 

dBW N/S 20 

400.15-401.00 

MHz 

I ≤ –147 

dBW N/S 

177.5 kHz 

0.025 

1696-1710 MHz I ≤ –147 dBW N/S 20 1696-1710 MHz I ≤ –138 dBW N/S 2668 kHz 0.025 

Space to Earth 

Data 

Earth Stations 

Direct Data 

Readout 

8025-8400 MHz I ≤ –136 dBW N/S 40 MHz 20 

Rec. ITU

SA.102

ii For analog and digital receivers with 2 dBic antenna gain, the interfering signal power levels (dBW) in 

bandwidths are specified for reception at elevation angles greater than or equal to 25o. 
Table 8-3(cont) 

Summary of Interference protection criteria for science services 

8-16

Services Interference Protection Systems 

Frequency 

Bands CW & 

Noiselike 

Pulse Other 

Reference 

BW 

% 

Time 

Sour

Docum

8025-8400 MHz I ≤ –125 dBW N/S 0.25 8025-8400 MHz I ≤ –125 dBW N/S 20 8025-8400 MHz I ≤ –116 dBW N/S 

40 MHz 

0.25 

25.5-27.0 GHz I ≤ –137 dBW N/S 20 

Space to Earth 

Data 

Earth Stations 

Direct Data 

Readout 

(cont.) 25.5-27.0 GHz I ≤ –120 dBW N/S 10 MHz 0.25 

Rec. IT

SA. 1

High-speed 25.5-27.0 GHz I ≤ –136 dBW N/S 20 

Direct 

Data Readout 25.5-27.0 GHz I ≤ –122 dBW N/S 10 MHz 0.25 Rec. IT

SA. 1

1696-1710 MHz I ≤ –128 dBW N/S 20 1696-1710 MHz I ≤ –121 dBW N/S 5334 kHz 0.025 7750-7850 MHz I ≤ –128 dBW N/S 20 7750-7850 MHz I ≤ –115 dBW N/S 0.025 8025-8400 MHz I ≤ –131 dBW N/S 20 

Recorded Data 

Acquisition 

8025-8400 MHz I ≤ –117 dBW N/S 

100 MHz 

0.025 

Rec. IT

SA. 1
Table 8-3(cont) 

Summary of Interference protection criteria for science services 

8-17

Services Interference Protection Systems 

Frequency 

Bands CW & 

Noiselike 

Pulse Other 

Reference 

BW 

% 

Time 

Sourc

Docume

25.5-27.0 GHz I ≤ –134 dBW Recorded Data N/S 20 Acquisition 

(cont.) 25.5-27.0 GHz I ≤ –118 dBW N/S 10 MHz 0.25 Rec. ITU

SA. 102

1670-1710 MHz I ≤ –153.8 dBW N/S 20 1670-1710 MHz I ≤ –148.6 dBW N/S 2.6 MHz 0.025 

25.5-27.0 GHz I ≤ –131.7 dBW N/S 20 

Direct Data 

Readout 

Space-to-earth 

25.5-27.0 GHz I ≤ –116.3 dBW N/S 10 MHz 0.25 

Rec. ITU

SA. 116

1670-1710 MHz I ≤ –167.5 dBW N/S 20 1670-1710 MHz I ≤ –160.4 dBW N/S 4 kHz 0.025 1670-1710 MHz I ≤ –153.4 dBW N/S 20 

Data 

Dissemination 

Space-to-earth 

1670-1710 MHz I ≤ –148.1 dBW N/S 2.11 MHz 0.025 

Rec. ITU

SA. 116

2025-2110 MHz I ≤ –136.7 dBW N/S 20 Command Data Acquisition 

(CDA) Station 

Earth-to-space 2025-2110 MHz I ≤ –133.4 dBW N/S 2.11 MHz 0.025 Rec. ITU

SA. 116
Table 8-3(cont) 

Summary of Interference protection criteria for science services 

8-18

Services Interference Protection Systems 

Frequency 

Bands CW & 

Noiselike 

Pulse Other 

Reference 

BW 

% 

Time 

Sourc

Docume

2025-2110 MHz I ≤ –147.8 dBW N/S 20 Command Data Acquisition 

(CDA) Station 

Earth-to-space 

(cont.) 

2025-2110 MHz I ≤ –140.7 dBW N/S 

4 kHZ 

0.025 

Rec. ITU

SA. 116

401-403 MHz I ≤– 178.8 dBW N/S 20 Service Data Collection Links 

Non-GSO 

Space Station 401-403 MHz I ≤ –174.7 dBW N/S 1.6 kHZ 0.1 Rec. ITU

SA.116

401-403 MHz I ≤ –187.4 dBW N/S 100 Hz 20 Service Data Collection Links 

GSO Space 

Station 401-403 MHz I ≤ –173.4 dBW N/S 4 kHz 0.1 

Rec. ITU

SA.116

2025-2110 MHz I ≤ –188.9 dBW N/S 20 Command and Data 

Acquisition 

Station (CDA) 2025-2110 MHz I ≤ –183.7 dBW N/S 100 Hz 0.025 Rec. ITU

SA.116

137-138 MHz I ≤ –158.3 dBW N/S 20 137-138 MHz I ≤ –151.1 dBW N/S 8.32 kHz 0.1 

1670-1690 MHz I ≤ –194.0 dBW N/S 20 

Service Links 

Earth Station 

Non-GSO Data 

Collection 

GSO Data 

Collection 

CDA Station 1670-1690 MHz I ≤ –181.5 dBW N/S 100 Hz 0.025 

Rec. ITU

SA.116
Table 8-3(cont) 

Summary of Interference protection criteria for science services 

8-19

Services Interference Protection Systems 

Frequency 

Bands CW and 

Noiselike 

Pulse Other 

Reference 

BW 

% 

Time 

Sour

Docum

460-470 MHz I ≤ –187.3 dBW N/S 20 GSO Data Platform 

Collection 

Integration 460-470 MHz I ≤ –182.1 dBW N/S 100 Hz 0.1 Rec IT

SA.11

Near 1.4 GHz I ≤ –171 

dBW N/S 27 MHz 

Near 2.7 GHz I ≤ –174 dBW N/S 10 MHz 

Near 4 GHz I ≤ –161 dBW N/S Near 6 GHz I ≤ –164 dBW N/S 100 MHz 

Near 11 GHz I ≤ –163 dBW N/S 20 MHz Near 15 GHz I ≤ –166 dBW N/S 50 MHz Near 18 GHz I ≤ –155 dBW N/S Near 21 GHz I ≤ –163 dBW N/S 

Passive 

 Sensor 

22.235 GHz I ≤ –160 dBW N/S 

100 MHz 

See 

Footnoteiii

Rec. IT

SA. 1

iii In shared bands, the specified interfering signal power levels may be exceeded for no more than 5% 

cells where data loss occurs randomly and for no more than 1% where loss occurs systematically. Tinterfering signal levels may be exceeded for no more than 0.001% time for three dimensional measuatmospheric temperature or gas concentration. 
Table 8-3(cont) 

Summary of Interference protection criteria for science services 

8-20

Services Interference ProtectionSystems 

Frequency 

Bands CW & 

Noiselike 

Pulse Other 

Reference 

BW 

% 

Time 

Source 

Documen

Near 24 GHz I ≤ –163 dBW N/S Near 31 GHz I ≤ –163 dBW N/S 100 MHz See Footnoteiv Rec. ITU-R SA. 1029 Near 37 GHz I ≤ –156 dBW N/S 100 MHz See Footnote iv Rec. ITU-R SA. 1029 

50.2-50.4 GHz I ≤ –161 dBW N/S 52.6-59.0 GHz I ≤ –161 dBW N/S 60.3-61.3 GHz I ≤ –161 dBW N/S 

100 MHz N/S N/S 

Near 90 GHz I ≤ –153 dBW N/S 200 MHz Rec. ITU-R SA. 1029 

Passive 

 Sensor 

(cont). 

100.49-380.20 

GHz 

I ≤ –160 

dBW N/S 200 MHz 

See 

Footnoteiv Rec. ITU-R 

SA. 1029 

Active Sensors 

Synthetic 

Aperture 

Radar (SAR) 

Near 400 MHz I ≤ –138 dBW N/S 10 MHz N/S Rec. ITU-R SA.1166 

iv In shared bands, the specified interfering signal levels may be exceeded for no more than 5% of all m

where data loss occurs randomly and for no more than 1% where loss occurs systematically. The sp

signal levels can be exceeded for no more than 0.001% time for three dimensional measurements of temperature or gas concentration. 
Table 8-3(cont) 

Summary of Interference protection criteria for science services 

8-21

Service Interference Protection 

Systems 

Frequency 

Bands CW & 

Noiselike 

Pulse Other

Reference 

BW 

% 

Time 

Sourc

Docume

Near 5.3 GHz I ≤ –123 dBW N/S 100 MHz

13.0-14.0 GHz I ≤ –119 dBW N/S 320 MHz Altimeters 

35.5-36.0 GHz I ≤ –112 dBW N/S 450 MHz 

N/S Rec. ITU

SA.116

Near 5.3 GHz I ≤ –155 dBW N/S 

13.0-14.0 GHz I ≤ –155 dBW N/S Scatterometers Spot-beam antenna 

35.5-36.0 GHz I ≤ –158 dBW N/S 

10 kHz N/S Rec. ITU

SA.116

13.0-14.0 GHz I ≤ –150 dBW N/S Precipitation 

Radars 35.0-36.0 GHz I ≤ –152 dBW N/S 600 kHz N/S Rec. ITU

SA.116

35.5-36.0 GHz I ≤ –155 dBW N/S Cloud Profiling 

Radars 94-94.1 GHz I ≤ –155 dBW N/S 300 kHz N/S Rec. ITU

SA.116
Table 8-3(cont) 

Summary of Interference protection criteria for science services 

8-22

Services Interference Protection Systems 

Frequency 

Bands CW & 

Noiselike 

Pulse Other 

Reference 

BW 

% 

Time 

Sourc

Docume

RADIO ASTRONOMICAL MEASUREMENTS 

13.36-13.41 

MHz 

I ≤ –248 

dBW N/S 

25.55-26.70 MH I ≤ –249 dBW N/S 

73.0-74.6 MHz I ≤ –258 dBW N/S 

150.05-153.0 

MHz 

I ≤ –259 

dBW N/S 

322.0-328.6 

MHz 

I ≤ –258 

dBW N/S 

406.1-410.0 

MHz 

I ≤ –255 

dBW N/S 

608-614 MHz I ≤ –253 dBW N/S 

1400-1427 MHz I ≤ –255 dBW N/S 

1610.6-1613.8 

MHz 

I ≤ –238 

dBW N/S 

1.66-1.67 GHz I ≤ –251 dBW N/S 

2.69-2.7 GHz I ≤ –247 dBW N/S 

Radio 

Astronomy 

4.99-5.0 GHz I ≤ –241 dBW N/S 

1 Hz N/S Rec. ITU

RA.76
Table 8-3(cont) 

Summary of Interference protection criteria for science services 

8-23

Services Interference Protection Systems 

Frequency 

Bands CW & 

Noiselike 

Pulse Other 

Reference 

BW 

% 

Time 

Sourc

Docume

10.6-10.7 GHz I ≤ –240 dBW N/S 

15.35-15.4 GHz I ≤ –233 dBW N/S 

22.1-22.5 GHz I ≤ –233 dBW N/S 23.6-24.0 GHz I ≤ –233 dBW N/S 31.3-31.8 GHz I ≤ –228 dBW N/S 42.5-43.5 GHz I ≤ –227 dBW N/S 

86-92 GHz I ≤ –222 dBW N/S 

105-116 GHz I ≤ –222 dBW N/S 182-185 GHz I ≤ –216 dBW N/S 217-231 GHz I ≤ –215 dBW N/S 

Radio 

Astronomy 

 (cont.) 

265-275 GHz I ≤ –213 dBW N/S 

1 Hz N/S Rec. ITU

RA.76
Table 8-3(cont) 

Summary of Interference protection criteria for science services 

8-24

Services Interference Protection Systems 

Frequency 

Bands CW & 

Noiselike 

Pulse Other 

Reference 

BW 

% 

Time 

Sourc

Docume

325.3 MHz I ≤ –215 dBW N/S 

611 MHz I ≤ –211 dBW N/S 

1413.5 MHz I ≤ –209 dBW N/S 

2695 MHz I ≤ –204 dBW N/S 4995 MHz I ≤ –198 dBW N/S 

10650 MHz I ≤ –192 dBW N/S 15375 MHz I ≤ –187 dBW N/S 23800 MHz I ≤ –192 dBW N/S 43000 MHz I ≤ –173 dBW N/S 

Very Long 

Baseline 

Interferometry 

(VLBI) 

86000 MHz I ≤ –166 dBW N/S 

1 Hz N/S Rec. ITU

RA.76
8-25

REFERENCES: 

1

 Rec. ITU-R SA.363-5, Space Operation Systems: Frequencies, bandwidths and 

protection criteria (1994); Rec. ITU-R SA.609-1, Protection Criteria for 

Telecommunication Links for Manned and Unmanned Near-Earth Research 

Satellites (1992); Rec. ITU-R SA.1155, Protection Criteria Related to the Operation 

of Data Relay Satellite Systems (1995); Rec. ITU-R SA.1157, Protection Criteria for 

Deep-Space Research (1995), Rec. ITU-R SA.1396, Protection Criteria for the 

Space Research Service in the 37-38 GHz and 40-40.5 GHz bands (1999). 

2 Rec. ITU-R SA.1263, Interference Criteria for Meteorological Aids Operated in the 

400.15-406 MHz and 1668.4-1700 MHz Bands (1997).

3 Rec. ITU-R SA.1022-1, Methodology for Determining Interference Criteria for 

Systems in the Earth Exploration-Satellite and Meteorological-Satellite Services

(1999).

4 Rec. ITU-R SA.1025-3, Performance Criteria for Space-to-Earth Data Transmission 

Systems Operating in the Earth Exploration-Satellite and Meteorological-Satellite 

Services using Satellite in Low-Earth Orbit (1999).

5 Rec. ITU-R SA.1026-3, Interference Criteria for Space-to-Earth Data Transmission 

Systems Operating in the Earth Exploration-Satellite and Meteorological-Satellite 

Services using Satellite in Low-Earth Orbit (1999). 

6 Rec. ITU-R SA.1159-2, Performance Criteria for Data Transmission and Direct 

Data Readout Systems Operating in the Earth Exploration-Satellite and 

Meteorological-Satellite Services using Satellites in Geostationary Orbit (1999).

7 Rec. ITU-R SA.1160-2, Interference Criteria for Data Transmission and Direct Data 

Readout Systems Operating in the Earth Exploration-Satellite and MeteorologicalSatellite Services using Satellites in Geostationary Orbit (1999). 

8 Rec. ITU-R SA.1162-1, Telecommunication Requirements and Performance 

Criteria for Service Links in Data Collection and Platform Location Systems in the 

Earth Exploration-Satellite and Meteorological-Satellite Services (2003). 

9 Rec. ITU-R SA.1163-2, Interference Criteria for Service Links in Data Collection 

Systems in the Earth Exploration-Satellite and Meteorological-Satellite Services

(1999).

10 Rec. ITU-R SA.514-3, Interference Criteria for Command and Data Transmission 

Systems Operating in the Earth Exploration-Satellite and Meteorological-Satellite 

Services (1997).
8-26

11 Rec. ITU-R SA.1028-1, Performance Criteria for Satellite Passive Remote Sensing

(2003). 

12 Rec. ITU-R SA.1029-1, Interference Criteria for Satellite Passive Remote Sensing

(2003).

13 Rec. ITU-R SA.1166-2, Performance and Interference Criteria for Active 

Spaceborne Sensors (1999).

14 Rec. ITU-R RA.769-1, Protection Criteria Used for Radioastronomical 

Measurements (2003).