Decoding Algorithms of LDPC Coded Superposition Modulation
Shancheng Zhao, Xiao Ma, Baoming Bai · IEEE Communications Letters · 2014
This paper is concerned with the design of decoding algorithms for superposition modulation systems in which all levels are coded with an identical binary low-density parity-check (LDPC) code. First, we present a computing-based iterative multistage decoding algorithm (CB-IMSDA). Then, we show that the considered system can be treated as a nonbinary LDPC (NB-LDPC) coded modulation system. Based on this, a joint decoding algorithm (JDA) is proposed. As a by-product, we propose a time-varying signaling scheme for the JDA. Numerical results show that 1) both the CB-IMSDA and JDA perform better than the standard iterative multistage decoding algorithm, and 2) extra coding gain can be obtained when the time-varying signaling scheme is employed.