Optimisation design of systematic LT codes over AWGN multiple access channel
Dachun Deng, Dazhuan Xu, Shengkai Xu · IET Communications · 2018
Systematic Luby transform (SLT) codes over the additive white Gaussian noise (AWGN) multiple access channels (MACs) are analysed in this study. The authors introduce a novel optimisation model extending from the point‐to‐point AWGN channels to design the degree distributions over the AWGN MACs, which dramatically improve the bit‐error‐rate (BER) performance of SLT codes. First, they extend the Gaussian approximation analysis of SLT codes to the AWGN MACs to analyse the asymptotic BER performance where the symmetric condition of log‐likelihood ratio message can no longer be assumed. Second, based on the asymptotic BER analysis over the AWGN MACs, they extend the existing optimisation model from the point‐to‐point AWGN channels to the AWGN MACs. Simulation results show that the degree distributions obtained in this study outperform other common degree distributions (optimised for single‐user AWGN channels) over the two‐user AWGN MACs.