An investigation of relationships between side information and information rate in slow-frequency-hop communications

Abstract

The erasure of unreliable symbols prior to decoding can significantly improve the performance of coded slow frequency-hop (SFH) systems. Four methods for obtaining side information, which is used to determine which symbols to erase, are considered. Two of the methods require the transmission of extra symbols. The other two methods require no overhead in the transmissions. Instead, they rely on soft outputs of the demodulator in making symbol decisions. The performance of each of these methods is investigated for SFH communications over channels with Rayleigh fading, partial-band interference, and wideband noise. The throughput of SFH systems that use Reed-Solomon coding is determined. The maximum information rate that may be achieved by a SFH system is determined for each of the methods of obtaining side information. This performance measure is based on channel capacity considerations, and it is therefore not restricted to Reed-Solomon codes.