摘要
针对较低信噪比(≤2dB)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,对载波频差用搜索窗辅助的单纯形算法进行搜索,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0.1dB以内的误码性能。
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 performance at the cost of some more computation complexity.
出处
《电子与信息学报》
EI
CSCD
北大核心
2009年第10期2416-2420,共5页
Journal of Electronics & Information Technology
基金
国家自然科学基金(60532070
60525107)
国家基础研究计划(2007CB310601)资助课题
关键词
LDPC码
载波同步
迭代载波恢复
LDPC code
Carrier synchronization
Iterative carrier recovery
