Design And Implementation Of Underwater Acoustic Communication Platform Based On OFDM

In the process of ocean development, as the information exchange technology for different platforms such as shore-underwater and underwater-underwater, underwater acoustic communications technology has become the research focus of engineering application in both military and commercial fields. The performance and quality of underwater acoustic communication is mainly affected by ocean acoustic channel, for the reason that its characteristics of random time-varying and space-varying are complex. Not only is the ambient noise strong,but also the phenomenon of decline and distortion during transmission is serious in ocean acoustic channel. The aim of underwater acoustic communication technology is to weaken and eliminate the impact of these unfavorable factors. Currently, the application research of orthogonal frequency division multiplexing(OFDM) technology in the field of underwater acoustic communication primarily shows the good performance in combating frequency selective fading, and possessing higher band utilization.This paper is to realize the signal acquisition,compression,OFDM modulation and demodulation, decompression, and recovery of voice on a hardware platform based on OFDM technology, and the learning of professional courses and DSP and other signal processing chips. The main works include simulation research of OFDM baseband system using MATLAB; welding and debugging of hardware circuit; development of OFDM modulation and demodulation program using C language on DSP and the initialization of corresponding onchip peripherals and configuration of AIC23B CODEC chip; generation of a FIFO buffer on FPGA and development of FIFO control timing using Verilog HDL language, and initialization and the POWER-ON reseting of AMBE-2000 VOCODER chip,control timing signals, and connection betweenr each two modules.Realization of each module is described in details in this paper, through the OFDM modulation and demodulation experiments of picture information, voice playback experiments, compression loopback test verifying that each module is designed to be correct, The joint testing of the whole system indicates there to be some practical values.