Performance of low-density parity-check coded modulation

This paper reports the performance of a family of nine accumulate-repeat-4-jagged-accumulate (AR4JA) low-density parity-check (LDPC) codes [4] when used in conjunction with binary phase-shift-keying (BPSK), quadrature PSK (QPSK), 8-PSK, 16-ary amplitude PSK (16-APSK), and 32-APSK. We also report the performance under various mappings of bits to modulation symbols, hard decision decoding, log-likelihood ratio (LLR) approximations, and decoder iterations. One of the simple and well-performing LLR approximations can be expressed in a general equation that applies to all of the modulation types.