强多径干扰下的水声通信均衡算法研究
Study of channel equalization of underwater acoustic communication in muitipath horizontal channel

水声信道的典型特点为强多径干扰、多普勒频移严重.锁相环-判决反馈均衡器(Phase-Lock Loop-Decision Feedback Equalization, PLL-DFE)是水声相干通信中克服信道多径干扰,消除码间干扰的主要技术手段.对抗多径干扰的判决反馈均衡自适应算法进行了改进,在快速自优化LMS算法的基础上进行了优化,提出了记忆快速自优化均衡(Memory Fast-Optimized LMS, MFOLMS)算法.该算法提高了均衡器的跟踪性能.在二阶锁相环和判决反馈均衡器的联合作用下,按照最小均方误差(Minimum Mean Square Error, MMSE)准则自动调节相应的参数,使均衡器达到最佳的性能.仿真和湖试数据处理结果均表明,该文提出的算法可以抵消多径的影响,提高通信系统的接收性能.
The underwater acoustic channel is characterized as a time-dispersive rapidly fading channel, which in addition exhibits Doppler instabilities. To eliminate intersymbol interference caused by multipath propagation, PLL-DFE is the main technical means. Based on the FOLMS, we optimize and improve the algorithm of equalization. MFOLMS can improve the tracking performance of equalizer. According to the MMSE, DFE can automatically adjust the corresponding parameter and achieve the best performance. The simulation and lake trial data processing results show that, the proposed algorithm can reduce the computational complexity, offset the impact of multipath, and improve the performance of communication system.