多元速率兼容LDPC码的自适应编码调制系统研究

Adaptive Coded Modulation System Based on Non-binary Rate-compatible LDPC Codes

本文设计了一种基于有限域GF(q)上的多元速率兼容LDPC(RC-LDPC)码结合高阶调制的自适应编码调制(Adaptive Coded Modulation,ACM)系统。并提出了多元RC-LDPC码在独立和相关衰落信道下的增量冗余型自适应编码调制方案。本方案中多元LDPC码码率从1/3到5/6灵活变化,以较低的系统复杂度,有效提高了系统的频带利用率。仿真结果表明:随着系统吞吐率提高,多元ACM系统相对于二元ACM系统具有越来越明显的编码增益,最高可达约9 d B。

In this paper, high-order adaptive coded modulation （ACM） schemes based on non-binary rate-compatible （RC） LDPC codes over GF（q） were designed. Further, the incremental redundancy schemes of non-binary RC-LDPC-based ACM system over independent and correlative fading channels were proposed. In the proposed schemes, the LDPC encoder can pro- vide a flexible code-rate range from 1/3 to 5/6 by shortening and puncturing algorithm. And the proposed schemes can im- prove the spectrum efficiency of system with little extra complexity. Simulations show that, with higher throughput rate, much more visible even 9 dB coding gain can be obtained by proposed non-binary ACM system than binary system.