一种基于低码率LDPC码的编码与导频联合辅助载波同步算法

晏辉; 唐发建; 张忠培

doi:10.3724/SP.J.1146.2010.00352

一种基于低码率LDPC码的编码与导频联合辅助载波同步算法

doi: 10.3724/SP.J.1146.2010.00352

基金项目:

国家863计划项目(2009AA01Z234)资助课题

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出版历程
- 收稿日期: 2010-04-06
- 修回日期: 2010-10-27
- 刊出日期: 2011-02-19

A Joint Assisted Carrier Synchronization Algorithm with Code and Pilot Based on Low Rate LDPC Code

摘要

摘要: 针对深空通信系统中编码和导频辅助载波同步算法分别存在同步范围与精度受限的问题，该文提出一种基于编码与导频联合辅助的载波同步算法。首先按照最优导频放置方式设计了一种基于相关函数和的粗同步算法，其频率估计量的精度接近CRB界；然后分析了导频结构对算法估计精度与范围的影响机理；接着通过加入导频及频率积分器的方式对基于期望最大的细同步算法进行了改进；最后用码率为1/12的低码率LDPC-Hadamard码对算法进行了仿真验证。结果表明新算法可以大幅提高同步参数的估计范围与精度，在一定的导频长度下能达到理想同步。
- 深空通信 /
- 载波同步 /
- 编码辅助 /
- LDPC-Hadamard码
Abstract: Considering that the code-aided and data-aided carrier recovery algorithms perform small synchronization range and big inaccuracy in low Signal to Noise Ratio (SNR) deep space communication systems, a joint assisted carrier synchronization algorithm with code and pilot is proposed. First a coarse synchronization algorithm with optimal pilot placement is constructed based on the sum of autocorrelation function of the pilots, whose frequency estimator can approximate Cramer-Rao Bound. The impact mechanism of pilot type on the trade-off between range and accuracy of estimation is analyzed. And then, a modified expectation maximization fine carrier synchronization is got with means of inserting pilot symbols and adding an integrator. Finally the simulations with the LDPC-Hadamard code with rate 1/12 verify that the new algorithm can increase synchronization range and improve accuracy, and achieve perfect synchronization with a certain amount of pilots at very low Signal to Noise Ratio.
- Deep space communications /
- Carrier synchronization /
- Code-Aided (CA) /
- LDPC-Hadamard code

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参考文献(1)

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