迭代接收机中软译码算法的低复杂度实现  

Low-complexity MAP Decoding for Iterative Receiver

作　　者：张君[1] 石铠源[1] 李静[1] 彭华[1] 

机构地区：[1]国家数字交换系统工程技术研究中心,郑州450002

出　　处：《系统仿真学报》2009年第9期2691-2695,共5页Journal of System Simulation

摘　　要：Max-Log-MAP算法因其更适于迭代处理已成为解决低信噪比条件下信号接收问题中的常用译码算法。提出一种新颖的性能/复杂度折衷策略来解决算法的实用化问题。新算法的巧妙之处在于利用MAP算法中误比特率最小的特点,通过简单的全局路径对比实现状态缩减;分析译码软输出对接收机迭代性能的影响,提出大噪声环境下的可靠度放大策略以改善性能。仿真结果表明,该算法在信噪比小于5dB时,能够十分逼近Log-MAP的误码性能,同时其实现复杂度只为Max-Log-MAP算法的40%～50%。A lower-complexity but higher-performance Max-Log-MAP decoding scheme for iterative detection in low SNR scenarios was proposed. As the two main contribution, one is a novel reduced-states approach, which only depends on these comparison results between two overall maximum likelihood paths at each epoch, is derived under the optimal bit MAP criterion; The other isproperly magnifying those soft-output values of decoder to achieve an improvement in terms of BER. Furthermore, simulation results show that the new decoding scheme has the BERperformance approaching that of Log-MAP, especially at the cost in computational complexity only 40%-50% of the traditional Max-Log-MAP＇s.

关 键 词：软输入软输出 BCJR算法 迭代译码 计算复杂度 

分 类 号：TN914.3[电子电信—通信与信息系统]