水声通信多通道最大似然联合均衡译码方法

水平阵是水声通信中常见的阵列接收形式，但垂直阵也有重要的应用场合。文章提出了一种适用于垂直阵的水声通信多通道最大似然联合均衡译码方法，相比现有仅在信道均衡中叠加各通道信号的多通道判决反馈均衡方法(Multichannel Decision Feedback Equalizer, M-DFE)，该方法利用最大似然准则，在一体化联合均衡译码过程中融合空间多通道接收信息，将空间增益直接用于抵抗水声信道多途衰落和译码纠错，有效提升了水声通信的性能。仿真结果表明，在误码率同样达到 10^-3的条件下，该方法所需信噪比相比 M-DFE方法可下降 2 dB。海上实验结果显示，在多种信道条件下，该方法实现正确译码的通信速率是 M-DFE方法的 1.25倍以上。

A multichannel maximum-likelihood joint equalization and channel decoding algorithm for underwater acoustic communication

Horizontal arrays is the common array form in underwater acoustic communication (UAC), however vertical arrays also has important application occasions. In this paper, a multichannel maximum-likelihood joint equalization and channel decoding algorithm for vertical array is proposed. Compared with the multichannel decision feedback equalization algorithm (M-DFE), which only superimposes the signals of each channel in the channel equalization, the proposed algorithm adopts the maximum-likelihood rule as the decoding criterion and integrates the information of each channel to calculate the decoding metric. In this way, the spatial gain is directly used for correction of decoding error and resistance of multipath fading, and the performance of UAC can be improved effectively. The simulation results show that when the error rate reaches 10^-3, the SNR required by the proposed algorithm can be reduced by 2 dB than the M-DFE algorithm. The experimental results show that, under different channel conditions, the communication rate of the proposed algorithm is more than 1.25 times higher than that of the M-DFE.