TECHNOLOGY AREAS: Electronics

ACQUISITION PROGRAM: Mobile User Objective System (MUOS), ACAT I program

The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), which controls the export and import of defense-related material and services. Offerors must disclose any proposed use of foreign nationals, their country of origin, and what tasks each would accomplish in the statement of work in accordance with section 3.5.b.(7) of the solicitation.

OBJECTIVE: Develop methods and algorithms for mitigating wideband interference in UHF SATCOM channels.

DESCRIPTION: Interference is one of the major impediments to Satellite Communications (SATCOM). Interference comes from sporadic unregulated RF transmission such as pirate radio and TV stations or other devices, as well as other sources. When strong interference is inside SATCOM channels, signals may be corrupted so that mission critical communications via satellite are disrupted. This impediment exists in both commercial and military systems.

Various methods and algorithms for mitigation of narrowband interference in UHF SATCOM systems have been proposed and implemented. However, wideband interference mitigation remains a difficult task. Coding and interleaving can only achieve limited mitigation. If some information about the wideband interference is available, e.g. its modulation format, then one could try to estimate the wideband interference and subtract it from the received signal. If no prior information is available, however, mitigation of wideband interference seems very difficult. This topic solicits innovative ideas for wideband interference mitigation in SATCOM channels without prior knowledge of the interference. For example, time and/or spatial diversity could be considered.

The developed system should operate as a "black box", which sits in between the original SATCOM antenna system and SATCOM receiver. The system should be able to mitigate multiple narrowband as well as wideband interferences, located anywhere within the UHF SATCOM frequency range. The interferences may appear and disappear sporadically, and the system should be able to adapt quickly to mitigate emerging interference with minimal communication down time. For signals received from the satellite, the mitigation system should be transparent to the receiver, simply passing the SATCOM signal from the antenna output to the receiver input with wideband interference removed. The ideal system should operate in real-time and require no operating parameter information from the antenna system or receiver.

PHASE I: Develop methods and algorithms for mitigating wideband interference in UHF SATCOM channels.

Tasks under this phase could include:
� Develop methods and algorithms
� Validate the proposed approach by computer simulation
� Estimate performance metrics such as bit error rate (BER), the effect of interference bandwidth and strength on BER, and adaptation time for effective mitigation
� Create an initial design of a prototype system

PHASE II: Implement and demonstrate the method(s) or algorithm(s) in a prototype device.

Tasks under this phase could include:
� Implement the new design and demonstrate its performance against expectations
� Evaluate measured performance characteristics versus expectations and make design/process adjustments as necessary
� Using a SATCOM simulator and/or actual over-the-air satellite signal, demonstrate the operation of the system and its effectiveness in mitigating various wideband interference scenarios in UHF SATCOM channels.

PHASE III: This phase will focus on further testing and integrating the technology with existing military SATCOM systems such as the Mobile User Objective System (MUOS).

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: The technologies produced under this program could be applied to any commercial SATCOM channels/systems that experience similar kinds of interference.

REFERENCES:
1. MacMullen, S.J., Strachan, B., "Interference on UHF SATCOM channels," MILCOM 1999

2. L Castanet, A Bolea-Alamañac, M Bousquet, "Interference and fade mitigation techniques for Ka and Q/V band satellite communication systems," Proc. 2nd International Workshop of COST Action, 2003

3. Kohl, M.; Wiesler, A.; Jondral, F., "Suppression of interferences over SATCOM links with transparent transponders," IEEE PIMRC conference, 1997

4. Oak, A. and Jen, T. "MUOS QoS Offerings and the Impact on Future UHF SATCOM". MILCOM 2006

KEYWORDS: MUOS; SATCOM; UFO; Interference Mitigation; Wideband

** TOPIC AUTHOR (TPOC) **

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