基于LDPC译码软信息的迭代载波恢复.pdf

第31 卷第10 期 电 子 与 信 息 学 报 Vol.31No.10 2009 年10 月 Journal of Electronics Information Technology Oct. 2009 基于LDPC 译码软信息的迭代载波恢复 包建荣① 詹亚锋② 陆建华①② ①(清华大学电子工程系 北京 100084) ②(清华大学宇航技术研究中心 北京 100084) 摘 要：针对较低信噪比(≤2 dB )下载波恢复难题，该文提出了基于LDPC 软信息的迭代载波恢复算法。该算法 以最大化LDPC 软信息绝对值的和为准则，对载波频差用有哪些信誉好的足球投注网站窗辅助的单纯形算法进行有哪些信誉好的足球投注网站，得到较准确的载波 估计并补偿。且它还采用 LDPC 软信息辅助的科斯塔斯环，来纠正残留载波偏差。仿真表明，它能有效纠正载波 偏差及克服相位模糊、跳周等问题，并以一定计算复杂度的代价，获得距理想QPSK 编码系统0.1 dB 以内的误码 性能。 关键词： LDPC 码；载波同步；迭代载波恢复 中图分类号：TN911.22 文献标识码：A 文章编号：1009-5896(2009)10-2416-05 Iterative Carrier Recovery Based on Soft Decision Metrics of LDPC Decoding ① ② ①② Bao Jian-rong Zhan Ya-feng Lu Jian-hua ① (Department of Electronic Engineering, Tsinghua University, Beijing 100084, China) ② (Tsinghua Space Center, Tsinghua University, Beijing 100084, China) Abstract: It is difficult to recovery carrier at rather low SNR (≤2 dB). An iterative carrier recovery via soft decision metrics of LDPC decoding is proposed. By maximizing the sum of the absolute value of the soft decision metrics of LDPC decoding with search window aided simplex algorithm, it can obtain accurate carrier estimate which will be compensated. Meanwhile, it can be combined with the Costas loop with LDPC decoding feedback to eliminate the residual carrier offsets. Simulation results indicate that it can overcome the problems of phase ambiguity, cycle slip and so on, and the performance of the QPSK system with it under carrier offsets is just within 0.1 dB of the ideal perfor