Performance analysis of sphere detection combined with the LDPC decoding

In this paper, we investigate the low density parity-check (LDPC) decoding algorithms and the detection methods of the multiple-input multiple-output (MIMO) systems. For LDPC codes, min-sum and layered decoding algorithms are discussed, and for MIMO detection, the maximum likelihood (ML) decision based on the sphere decoding algorithm is mainly analyzed. Also, the performance of the combination of the channel coding and space time coding is presented, which use the preceding methods respectively. In this LDPC coded system, the log-likelihood ratio (LLR) is propagated from LDPC decoder to the MIMO detector and then fed back, which would increase the decoding efficiency.