基于信道估计的判决反馈均衡器在时变水声信道中的应用研究

Implementation of channel-estimation-based adaptive decision feedback equalization in time-varying underwater acoustic channels

基于信道估计的自适应判决反馈均衡器,简称CE-DFE均衡器,能根据信道估计结果自适应更新判决反馈均衡器的前馈和反馈抽头系数,具有较强的信道跟踪能力.将CE-DFE均衡器应用水声相干通信,研究了其在非时变和时变浅海水声信道中的均衡效果,比较了其与传统的最小二乘回归-判决反馈均衡器(RLS-DFE)的性能差异.仿真表明:在非时变浅海水声信道中,两种均衡器的性能基本相同,在所研究的信道中,信噪比大于10dB时,输出误比特率小于10^(-3);在时变浅海水声信道中,CE-DFE均衡器由于能根据信道参数自适应调节判决反馈均衡器的参数,其性能优于RLS-DFE均衡器.

To solve poor-performance problems of recursive least squares decision feedback equalizer(RLS-DFE)in time-varying underwater environment,channel-estimation based decision feedback equalization,termed as CE-DFE equalizer is introduced for coherent underwater acoustic communication in this paper.The performance of CE-DFE equalizer is simulated and compared with that of RLS-DFE equalizer over two different shallow water acoustic channel:time-invariant and time-varying channels.Computer simulations show that both the CE-DFE and RLS-DFE equalizers have good performance over time-invariant shallow water acoustic channel.RLS-DFE equalizer has poor performance over the time-varying shallow acoustic channel.However,CE-DFE equalizer holds good performance due to its ability to track the variation of the channels.