Iterative Demodulation and Decoding for Protected Satellite Communications

Military satellite communications Milsatcom systems use frequency hopping over a wide bandwidth to provide protection from hostile jamming, interception, and detection. These systems are being challenged to transport more information at higher rates, among smaller and more mobile terminals, with little or no increase in allocated bandwidth. Meeting these challenges requires advanced bandwidth-efficient and power-efficient signaling techniques. This article describes an approach to error-control coding and modulation that can help achieve the requirements of future Milsatcom systems. The receiver in this approach iterates between demodulation and decoding, which enables near-coherent performance with minimal reference symbol overhead. Also, the decoding process is augmented so that, in the presence of jamming, the receiver estimates the jammer state and combines information appropriately from different hops.