WGS Air-Interface for AISR Missions

Wideband Global SATCOM (WGS) system will provide a new generation of wideband military satellite communication (MILSATCOM) capability. In response to the bandwidth demand set forth by Airborne Intelligence Surveillance Reconnaissance (AISR) requirements, a Channelizer radio frequency (RF) Bypass mode is being added to the payloads of WGS flights 4 and 5. The proposed architecture enhancement to the baseline WGS payload allows two high data rate services to be uplinked from unmanned aerial vehicles (UAVs) to the satellite. These high data rate services are routed through two 400-MHz payload channels, and downlinked to ground receive terminals. The major objective of this paper is to identify waveforms that can support AISR missions and optimize the WGS resources. The results of WGS system analysis and technical constraints for implementing AISR missions are described. The critical design requirements are derived and a new waveform with power-efficient modulation and channel capacity-approaching codes is proposed. In addition, an innovative receiver is depicted, which is unique that the demodulation is involved in the iterative detection. The description expands the waveform design philosophy of pursuing a simple implementation at the size, weight and power (SWAP) constrained transmitter and achieving superb link performances with advanced receiver functions at the ground terminals, which may possess more powerful processing resources. In addition, a time division multiple access (TDMA) based channel-sharing scheme is proposed to use the RF Bypass mode for low data rate transmissions.