一种针对深海远程信道的M元扩频接收算法

An M-ary Spread Spectrum Receiver Algorithm for Long Range Deep Sea Channels

摘要:

深海远程水声信道具有多径时延长、信道非最小相位等特点，当扩频增益不足以抑制多径干扰时，信道均衡是必要的。将双向判决反馈均衡技术应用于 M 元扩频水声通信系统，减小判决反馈均衡错误传播概率，提高常规符号判决反馈均衡器输出信噪比。通过正交 M 元扩频解扩结果比较正向和反向信道特性， 调整分集合并权重因子。和等增益合并正反向均衡输出结果的传统双向判决反馈均衡方法相比，该算法可进一步提高接收处理增益。通过仿真深海远程水声信道获得的试验结果证实了算法的有效性。

Abstract:

Deep-sea long-range underwater acoustic channels have the characteristics of multipath time-delay and non-minimum phase. When the spreading gain is not enough to suppress the multi-path interference，channel equalization is necessary. In this paper，bi-directional decision feedback equalization (BiDFE) technique is applied to the M-ary spread spectrum underwater acoustic communication system to reduce the decision feedback equalization error propagation probability and improve the output signal-to-noise ratio of the conventional symbol decision feedback equalizer. The despreading results of orthogonal M-ary spread spectrum are used to compare the characteristics of forward and reverse channels，then the diversity and weight factor is adjusted. Compared with the traditional BiDFE method of combining equal gain with forward and backward equalizing output，the proposed algorithm further improves the received processing gain. The validity of the algorithm is verified by the simulation results of deep-sea long-distance underwater acoustic channel.