浅海远程水声Turbo编码跳频通信研究

A Turbo coded frequency hopping system for long-distance shallow water acoustic communications

结合Turbo编码和水声跳频通信技术，基于数字信号处理（DSP）成功地研制出了一种高效的抗多途、抗噪声浅海远程水声通信系统。该系统针对浅海远程水声信道的低信噪比、强多途及快速时变衰落特点，采用一种联合有限脉冲响应（FIR）数字窄带滤波和线性调频信号互相关检测的快速、精确的帧同步方法；利用快速频谱分析进行解调，使用复杂度较低的软输出维特比算法（SOVA）进行译码，并对其译码流程进行改进和优化，充分保证接收水声信号DSP处理的实时性。厦门港超浅海水声数据传输试验获得了其传输距离5km，通信速率250bit／s，误比特率10^-5的良好通信性能，证实了该水声通信系统的有效性、可靠性和稳健性。

A high efficienct anti-multipath, anti-noise long-distance underwater acoustic communication system based on digital signal processing （DSP） was designed successfully by combinative use of the Turbo code technique and the frequency hopping technique. This system uses a new rapid and exact frame synchronization technique based on the joint of the narrowband filter and the linear frequency modulation signals to overcome the low signal to noise ratio, strong multipath and rapidly time-varying fading of the long-distance shallow water acoustic channels. To assure the real-time of data processing by DSP, the FFT is used to demodulate the received signals, and an improved and optimized soft-out Viterbi algorithm （SOVA） with a low complexity is adopted for decoding. The communication system achieved its performances of the communication distance of 5kin, the data rate of 250bits/s, and the bit error ratio of 10^-5 in the Xiamen harbor test, which proved its validity, reliability and stabilization.