Turbo码的一种全新的SOVA译码算法  

A new SOVA based decoding scheme for Turbo codes

作　　者：张路[1] 万蕾[1] 匡镜明[1] 

机构地区：[1]北京理工大学,北京100081

出　　处：《通信学报》2002年第8期24-32,共9页Journal on Communications

摘　　要：SOVA算法因其译码时延低于MAP算法已成为Turbo码的实用译码算法。本文提出了一种放弃软判决值更新处理的全新的SOVA算法。该算法的独到之处在于,综合利用对栅格图的正向和反向搜索,从而实现了通过全局路径比较来产生软输出值。仿真结果表明,与传统SOVA算法相比这种全新的SOVA算法在不会明显增加译码计算量的前提下,显著地改善了译码性能。同时,其误码率性能在高信噪比时略优于Max-Log-MAP算法,并且已经逼近MAP算法。SOVA is more practical than MAP in the algorithms for decoding Turbo codes, because of its shorter decoding delay. This paper proposes a new SOVA to improve the performance of general SOVA. The new algorithm abandons updating process for soft value and produces soft value by comparing metrics between two integral pathes, based on synthetically utilizing forward and backward searching in trellis. The computer imitation results show that the new SOVA obviously improves BER performance compared with general SOVA, while decoding complexity would not increase obviously. Moreover, BER performance of the new SOVA is a little superior to that of Max-Log-MAP at higher SNR and hasapproached that of MAP.

关 键 词：TURBO码 第三代移动通信 SOVA译码算法 软输出维特比算法 全局最大似然路径 

分 类 号：TN929.5[电子电信—通信与信息系统]