FORWARD ERROR CORRECTION CODING WITHOUT BANDWIDTH EXPANSION

This chapter focuses on two modulation waveforms that provide coding gain without requiring additional bandwidth beyond that of the transmitted information symbol. The two waveforms are M‐ary multi‐h continuous phase modulation (CPM) and multiphase shift keying (MPSK) trellis‐coded modulation (TCM). The coding gain for these waveforms is provided by the inclusion of redundant phase states that behave much like the redundant parity bits in conventional bandwidth expansion with forward error correction (FEC) coding techniques. The chapter provides a case study that focuses on the 2‐h 4‐ary full response CPM waveform. This case study describes the processing requirements for 2‐h 4‐ary full response modulation (1REC) CPM waveform modulation and demodulation and presents some performance results for the U.S Navy UHF satellite relay communication system. This study focuses on the communication data rates, modulation indices, and the resulting bit‐error and spectral performance through the 25 kHz satellite channel.