水声OFDM系统多普勒频移和信道的联合估计

Joint Doppler Frequency Offset Mitigation and Channel Estimation for Underwater Acoustic OFDM

水声通信是近年来研究的热点,但由于水声信道本身的问题,如多径延迟、多普勒频移、信号衰减、窄带宽、时变等特点,使得水声通信传输数据速率低,传输误码率(BER)高.正交频分复用(OFDM)在水声通信中具有很大优势,但它对载波频率偏移(CFO)敏感.基于循环前缀正交频分复用(CP-OFDM)的水声通信系统,对多普勒引起的CFO进行补偿,同时利用延迟-多普勒域中的稀疏性对水声双选信道进行压缩感知信道估计.通过计算机仿真和水池实验,验证了这种双选信道估计的有效性和可靠性.

Underwater acoustic communication is a research hotspot in recent years. However, the problem of underwater acoustic channel itself,such as severe multipath delay, doppler shift, signal attenuation, narrow bandwidth, time-varying, led to low data rate and high rate of transmission error. Orthogonal frequency division multiplexing （OFDM） has a great advantage in the underwater a- coustic communication. But it is sensitive to carrier frequency offset （CFO）. We first discuss cyclic prefix orthogonal frequency divi- sion multiplexing （CP-OFDM） system model,then compensate for the CFO caused by the doppler and make CS-based channel esti- mation by exploiting sparsity in the delay-doppler domain. Through computer simulation and pool experiments verified the validity and reliability of this doubly selective channels estimation.