高速移动环境下OTSM迭代检测算法研究

Research on OTSM Iterative Detection Algorithm in High-speed Mobile Environment

正交时序复用(Orthogonal Time Sequency Multiplexing,OTSM)通过级联时分和沃尔什-哈达玛(WHT)复用将信息符号在时延和序列域进行复用。由于WHT在调制解调过程不需要进行复杂的乘法运算,相比于正交时频空(OTFS)调制有更低的调制复杂度。该文针对高速移动环境下的OTSM系统提出了一种二级均衡器:首先利用信道矩阵的稀疏性和带状结构在时域逐块进行低复杂度MMSE检测;随后采用高斯-赛德尔(GS)迭代检测进一步消除残余符号干扰。仿真结果表明,所提算法与基于单抽头频域均衡的GS迭代检测算法相比,采用16QAM调制且误码率为10–4时有1.8 dB性能增益。

Orthogonal Time Sequency Multiplexing(OTSM)multiplexes information symbols in the delaysequence domain through concatenated time division and Walsh-Hadamard multiplexing.Due to the Walsh-Hadamard Transform(WHT)does not require complex multiplication operations in the modulation and demodulation process,it has lower modulation complexity than Orthogonal Time-Frequency Space(OTFS).In this paper,a two-stage equalizer is proposed for OTSM systems in high-speed mobile environments.First,lowcomplexity MMSE detection is performed block-by-block in the time domain by utilizing the sparsity and band structure of the channel matrix;Then Gauss-Seid(GS)iterative detection further removes residual symbol interference.The simulation results show that,compared with the GS iterative detection algorithm based on single-tap frequency domain equalization,the proposed algorithm has a performance gain of 1.8 dB when 16QAM modulation is used and the bit error rate is 10–4.