Forced-convergence decoding for LDPC-coded modulation

• Published in: Science China. Information sciences Vol. 56; no. 1; pp. 143 - 153
• Main Authors: Dai, LiYun, Yang, HongWen, Fan, JianXiao, Rao, WenYuan
• Format: Journal Article
• Language: English
• Published: Heidelberg SP Science China Press 2013; Springer Nature B.V
• Subjects: Algorithms; Channels; China; Complexity; Computer Science; Computer simulation; Constellations; Convergence; Decoding; Error correcting codes; Information Systems and Communication Service; LDPC; Modulation; Nodes; Parity; Research Paper; Tanner图; 低密度奇偶校验; 复杂度; 收敛; 编码调制; 解码算法; 译码; low-density parity-check code; coded modulation; forced-convergence; belief propagation decoding
• ISSN: 1674-733X; 1869-1919
• DOI: 10.1007/s11432-012-4710-8

Low-density parity-check （LDPC）-coded modulation has attracted much attention for its outstand- ing performance in a bandwidth-limited channel. However, it involves relatively high decoding complexity. Owing to different convergence behaviors of variable nodes, the nodes detected early can be deleted from the Tanner graph, which reduces the size of the parity-check matrix iteration by iteration and thus the decoding complexity. In this paper, we propose a new decoding algorithm for LDPC-coded modulation with reduced complexity. In addition, by deleting the converged bits from the modulation constellation and updating the hit metrics of the demapper with the reduced constellation, more accurate estimation of the bits can be achieved. Simulation results show that, compared with conventional decoding schemes, the proposed method not only greatly reduces the overall decoding complexity for LDPC-coded modulation but also significantly improves decoding performance.