| 摘要: |
| 传统导频辅助的短数据包中用于包检测、同步的前导训练序列占比开销过大，造成传输效率严重下降。基于循环码移位键控调制（Cyclic Code Shift Keying，CCSK）的短数据包可以消除前导同步序列开销，有效提高短包的传输效率，然而，其基于CCSK循环相关的盲定时同步在较低信噪比（Signal-to-Noise Ratio，SNR）下性能受限。为了解决上述问题，提出了一种基于非二进制低密度奇偶校验（Non Binary Low Density Parity Check，NB-LDPC）码的CCSK短数据包盲定时同步方案。该方案利用NB-LDPC的校验矩阵构造目标函数，以累加目标函数满足校验矩阵的总数作为同步度量准则，通过NB-LDPC译码校验实现了短数据包码片级盲定时估计值。同时，为了降低码辅助同步的运算量，通过提取码片级盲定时同步误差的错误概率分布规律，设计了低复杂度码辅助校正方案。仿真结果表明，基于NB-LDPC的码辅助短数据包能克服低信噪比情况下盲定时误差造成的译码错误平台，对比无码辅助同步的情况在误码率10－3时性能提升约2 dB，比现有码辅助同步方法提升约0.4 dB，在26有限域中计算量降低了81.25%。 |
| 关键词: NB-LDPC 短数据包 定时同步 CCSK 码辅助同步 |
| DOI：10.20079/j.issn.1001-893x.240417001 |
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| 基金项目:国家自然科学基金资助项目（61871473）；海军工程大学自主研发计划项目（2023503090） |
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| A Multi-binary LDPC Code-assisted Blind Timing Synchronization Algorithm for Short Packets |
| WANG Zhen,SONG Guangming,DOU Gaoqi,WANG Hao,ZHANG Yufei |
| (1.Institute of Electronic Engineering,Naval University of Engineering,Wuhan 430033,China;2.Unit 91977 of PLA,Beijing 100036,China) |
| Abstract: |
| The leading training sequences for packet detection and synchronization account for too much overhead in the traditional guide frequency-assisted short packets,resulting in a serious degradation of transmission efficiency.Short packets based on cyclic code shift keying(CCSK)can eliminate the overhead of the pilot synchronization sequence and effectively improve the transmission efficiency of short packets,however,its blind timing synchronization based on CCSK cyclic correlation has a limited performance at lower signal-to-noise ratio(SNR).In order to solve above problems,a blind timing synchronization scheme based on nonbinary low density parity check code(NB-LDPC)for CCSK short packets is proposed.The scheme utilizes the check matrix of NB-LDPC to construct the objective function,takes the total number of accumulated objective functions satisfying the check matrix as the synchronization metric criterion,and achieves the short packet code-slice level blind timing estimation value through the NB-LDPC decoding and checking.Meanwhile,in order to reduce the arithmetic of code-assisted synchronization,a low-complexity code-assisted correction scheme is designed by extracting the error probability distribution law of the code-slice-level blind timing synchronization error.The simulation results show that the NB-LDPC-based code-assisted short packets can overcome the decoding error platform caused by the blind timing error in low SNR,performance improvement of about 2 dB at bit error rate 10－3 is achieved compared with the case without code-assisted synchronization.Approximate0.4 dB improvement over existing code-assisted synchronization methods is realized,and the computation is reduced by 81.25%in 26 finite domain. |
| Key words: NB-LDPC short data packet blind synchronization CCSK code-assisted synchronization |
