基于时反镜能量检测法的循环移位扩频水声通信

海面的起伏和多普勒效应使得接收信号的载波相位发生跳变以及水声信道的多途扩展使得接收信号波形发生畸变,这严重影响循环移位扩频系统的性能.本文提出循环移位能量检测器算法,通过检测循环移位匹配滤波器的输出能量对系统进行解码,可有效解决载波相位跳变对循环移位扩频系统的影响;将时间反转镜技术与循环移位能量检测器相结合,进一步提出时反镜能量检测器算法,利用已检测到的符号对信道进行实时估计并进行时反处理,抑制了水声信道多途扩展的影响,保证了循环移位扩频系统可在低信噪比条件下工作.通过大连海上试验以及莲花湖湖上试验验证,在复杂水声信道多途扩展、载波相位跳变和低信噪比条件下实现了低误码水声通信.

Cyclic shift keying spread sp ectrum underwater acoustic communication using time reversal energy detector

The fluctuation of sea surface and the Doppler effect cause carrier phase fluctuations of received signal, and the multipath expansion of the underwater acoustic channel makes received signal distorted, which can seriously influence the decoding performance of the cyclic shift spread spectrum system. In this paper, we propose cyclic shift energy detector (CS-ED) algorithm for cyclic shift keying spread spectrum system, which can solve the problem about the influence of carrier phase fluctuation by detecting the output energy of cyclic shift matched filter. The CS-ED combined with time reversal mirror is further proposed and analyzed in this paper by using a time-updated channel impulse-response estimate as a (match) filter to do time reversal processing to mitigate the multipath-induced interferences. Time reversal CS-ED method is simple and robust, which can make the system work in low SNR. Dalian Sea test validation and Lianhua lake test validation are carried on, showing that the low bit error rate underwater acoustic communication is achieved under the condition of multi-path extension, carrier phase fluctuation and low signal-to-noise ratio.