Performance simulation and analysis of alternative Automatic Link Establishment and Link-16/JTIDS waveforms with Reed Solomon encoding and hybrid soft decision-hard decision decoding

Hybrid hard decision-soft decision (HD/SD) decoding is a novel decoding technique for Reed Solomon (RS) codes. HD/SD decoding utilizes traditional hard decision RS decoding where the received block is either decoded correctly or a decoding failure exists. In the event of a decoding failure, channel reliability information is used to identify received code symbols with a low probability of being correctly received and to generate new code symbol estimates that are used in the traditional RS decoding algorithm. HD/SD RS decoding was developed for use with bandwidth efficient modulation schemes such as M-ary phase-shift keying and has been examined only in an additive white Gaussian noise (AWGN) environment. This paper presents the performance simulation and analysis of proposed alternative waveforms for Automatic Link Establishment and the Link-16/Joint Tactical Information Distribution System utilizing orthogonal signaling and Reed Solomon (RS) encoding. The proposed modulation scheme is double-symbol 8-FSK, where two modulation symbols are used to transmit a single RS code symbol, and hybrid HD/SD decoding. In addition to AWGN, the effects of pulse-noise interference (PNI) are considered. An interesting result is that hybrid HD/SD decoding has better performance and error correction capability than either traditional HD decoding or other RS SD techniques that have been examined in the literature, especially when PNI is present. The proposed alternative waveforms provide more robust communication links and increased throughput.