水声信道是较为复杂的数据通信信道,为了满足水下安全可靠通信和组网的要求,提出了一种基于跳频技术的水下通信系统方案,建立了系统仿真模型和多径Rayleigh衰落水声信道模型。方案中采用了FH/MFSK调制技术,自适应跳频序列控制,信道纠错编码分别采用RS,卷积码,接收机采用空间分集,跳频序列控制的可控滤波器组以及基于周期图谱分析解码,并通过仿真研究比较了这些技术在水下多径信道中对系统性能的影响。结果表明采用该模型的通信系统水下跳频系统的具有很强稳健性,可以在低信噪比下具有良好的误码率性能。
The underwater acoustic channel is the more complex data communication channel.To satisfy the requirements on the security and reliability of underwater real-time communication and network,a kind of underwater frequency-hopping communications system was proposed,and the system simulation model as well as the Rayleigh fading multi-path additive underwater acoustic channel model were also constructed.FH/MFSK modulation,RS and Convolutional code and spatial diversity techniques were used in this system.Simulations were conducted to investigate the performances of them.The results show that the space division and variable filter Banks controlled by the frequency-hopping sequence as well as the spectrum estimation based on periodogram can improve the robustness of the system and have good BER performance under low SNR and multi-path conditions.