基于STFT的水声双扩展畸变信道检测算法

Approach to signal detection in doubly-spread channels based on STFT

针对主动声纳中时延扩展和多普勒扩展同时存在的双扩展畸变信道,提出了一种基于短时傅里叶变换(short-time Fourier transform,STFT)的时频副本相关器(time-frequency replica correlator,TFRC)。分析表明,时延扩展信道及多普勒扩展信道的最佳似然比检测器副本相关积分器(replica correlator integration,RCI)和分段副本相关器(segmented replica correlator,SRC)都是TFRC的特殊情况。数值仿真验证了TFRC的有效性,这种时-频处理方法为畸变信道稳健检测器的设计提供了一种新的思路。

In doubly-spread acoustic underwater channels,the received signal is dispersed in both time and frequency,which makes signal detection particularly challenging. The existing receiver performance is signaificantly degraded. A time-frequency framework is introduced, the proposed time frequency replica correlator （TFRC） based on short-time Fourier transform（STFT） generalizes existing receivers and considers that both the segmented replica correlator （SRC） and the replica correlation integration （RCI） are the special cases of the TFRC. Computer simulations are carried out to show the efficiency of the TFRC, and a promising substantial improvement in performance is obtained compared with existing receivers over doubly spread channels.