水声扩频通信中多假设反馈自适应均衡算法研究

Study on Multi-Hypothesis Decision Feedback Equalization for DS/SS-CDMA Underwater Acoustic Communication

研究了复杂多变的水声信道条件下直接序列扩频-码分复用(DS/SS-CDMA)通信技术。本文将空间分集-多普勒频移补偿-自最佳自适应判决反馈均衡算法应用到水声DS/SS-CDMA通信,提出了基于码片速率的多假设反馈自适应均衡算法。应用该均衡算法可以恢复经过水声信道传输后扩频信号的相关特性。对实际的海上试验数据分析结果表明:算法以增加计算复杂性为代价显著提高了通信性能,在时变的多途扩散、多普勒扩散以及低信噪比的水声信道条件下可以保证低的通信误码率,算法性能良好。

A study of chi Prate muhi -hypothesis decision feedback equalization algorithm for DS/SS -CDMA underwater acoustic communication is presented. Underwater acoustic communication channel is a delay - Doppler double spreading channel. Fading and Doppler spreading severely degrade the correlation characteristic of the spread spectrum signals, so Doppler shift compensation and equalization are needed before decoding. By applying Space diversity - Doppler compensation - Fast Self - Optimized adaptive decision feedback equalization algorithm into DS/SS- CDMA communication, a chi Prate multi- hypothesis adaptive decision feedback equalization algorithm for DS/SS - CDMA underw-ater acoustic communication is proposed and its performance is analyzed with real sea - trial data. At the price of computational complexity, the algorithm dramatically improves DS/SS- CDMA communication quality. Very low bit error rate is achieved under fast changing multi - path and Doppler shift condition, and the equalizer is stable under low SNR. The overall performance of this algorithm is a satisfactory.