# Presentation: 109806

## DoD Interim ReportTechnical Feasibility of Accommodating IMT-2000
Within the 1755-1850 MHz Band

- DoD Interim ReportTechnical Feasibility of Accommodating IMT-2000
- Within the 1755-1850 MHz Band

*Mike Williams*
*Joint Spectrum Center*
*Senior Engineer*
- 1 December 2000
- (410) 293-2681
- williamsm@jsc.mil

## STUDY CONTEXT

**  ****Directed by the President**
**  ****Multiple Bands Under Consideration in U.S.**
** ****806 - 960 MHz;  ****1710 - 1885 MHz****;  ****2500 - 2690 MHz**
**  ****DoD focus is ****1755-1850 MHz**** **
**  ****Provide the Use, Cost and Operational Impacts **
**	****and Trade-offs**
**  ****Scrutinized by NTIA, OMB and FCC **
**  ****Released to the Public**

## DOD IMT-2000 STUDY PLAN STRUCTURE

**DoD IMT-2000 Working Groups**

**High Level IMT-2000 Team**
**(HLIT)**
**DoD, DoC(NTIA), FCC, OMB**

_**Presidential **_
_**Directive Memorandum**_
**Advanced Mobile Communications /**
**Third Generation Wireless Systems**
**(13 October 2000)**

**Mid-Level IMT-2000 Team**
**(MLIT)**
**DoD, DoC(NTIA), FCC, OMB**

**NTIA**

**Study Planning**
**and Management**

## DoD IMT-2000 WORKING GROUPS

**OPERATIONAL**
**(Joint Staff )**

**TECHNICAL**
**(JSC)**

**COST**
**(DoD CAIG)**

**Steering Committee**
**OSAM Chair**

## STUDY PURPOSE

**  ****Evaluate the Sharing/Segmentation Options**
**	****1.  Share the full band **
**	****2.  Segment the band (Gov retains 1755-1805 MHz)**
**	****3.  Segment the band (Gov retains 1790-1850 MHz)**
**	****4.  Vacate/Lose the entire band**
**  ****Identify interference interactions**
**  ****Investigate feasible mitigation possibilities**
**	**

## TECHNICAL APPROACH

**Identify major incumbent DoD systems**
**Identify principal DoD analysis factors**
**Tech parameters, including interference thresholds**
**Operational scenarios**
**Determine IMT-2000 analysis factors**
**Perform 2-way interference analysis for different sharing/segmentation options**
**Assess results**

## MAJOR DOD SYSTEMS OPERATING IN 1755 - 1850 MHz

** ****TACTS/ACMI**
** ****Joint Tactical Combat Training System (JTCTS)**** **
**	****  **
**Tactical Radio Network Systems**
** ****Army Mobile Subscriber Equipment (MSE)**
** ****Navy/USMC Digital Wideband Transmission System (DWTS)**
**Space Operations:  TT&C**
**Tactical Data Links**
**Other Equipment / Systems Impacted  (150 + ****Land Warrior,**
**	****CIDDS, Corps of Engineers, UAV****)**

**MAJOR DOD SYSTEMS ****OPERATING IN 1755 - 1850 MHz**

## TECHNICAL APPROACHINTERFERENCE ANALYSIS

**Antenna coupling**
**Mainbeam-to-mainbeam, mainbeam-to-sidelobe**
**Path loss**
**Terrain dependent for fixed, known locations**
**Smooth earth mode for transportables, mobiles**
**Considered frequency dependent rejection**
**Many-to-one for aggregate IMT-2000 envir**
**To spaceborne, airborne receivers**
**One-to-one for terrestrial situations**
**Separation distance to prevent interference ****	****	****	****	****	****	**

## SUMMARY OF INTERIM RESULTS

**Full band sharing appears very difficult**
**Substantial separation distances required for co-tuned operation**
**Over 100 km for terrestrial systems**
**Over 400 km for airborne systems**
**SGLS receivers may be degraded by 2006**
**Segmentation plans will require access to additional spectrum in a comparable band**
**Loss of channels for radios and control links**
**Loss of links for ACTS, SGLS**
**Vacating band will require replacement spectrum**

## MITIGATION CONSIDERATIONS

**Examine possible mitigation options - DoD**
**Antenna relocation, shrouding, radiation fences**
**Sharing of event scheduling**
**Limitations on training locations and operations**
**Must maintain full operational capability**
**Examine possible mitigation options - IMT**
**Selected antenna orientations**
**“****Listen-before-transmit” capability**
**Dynamic, event-dependent frequency management**

## REMAINING EFFORTS

**Gather and characterize operational impacts for each option**
**Determine cost impacts associated with sharing/vacating**
**Complete technical assessments including other systems**
**Consolidate final report**
**Technical, operational, cost**
**Coordinate final report within DoD**