Design Of Underwater Acoustic Voice Communication System Based On OFDM

In recent years, with the development and utilization of ocean, people are paying more and more attention on research and development of the underwater voice communication system. Sound is the only energy form which is transmission in the water for long distance and is the effective underwater information transport carrier, thus underwater acoustic communication become a hot topic research inevitably. With the characteristics of narrow bandwidth, variant space-time-frequency and multi-path interference, the development of underwater acoustic communication is different from wireless communication. So it's an important research direction to find an effective way of underwater acoustic communication.As a result of resisting multi-path interference, resisting frequency selective fading and high frequency spectrum utilization, etc, orthogonal frequency division multiplexing (OFDM) technology is widely applied in underwater acoustic communication. After analyzes the theory of OFDM technology, a digital voice communication system is designed that is suit for underwater acoustical channel environment. In hardware platform, AMBE-2000 is used as compressed encoding and decompressed encoding. The chip TMS320VC5509A is used for modulating and demodulating, transmitting digital and analog signal with CODEC in digital communication scheme. In the design of software, speech signals are processed by IFFT/FFT OFDM technology, channel coding, interleaving technology and digital modulation in sub-carrier. And then the system is realized the real-time transmission of speech signals through physical layer interface program, combined with transmitting and receiving controlling programs.Through simulation analyses of the system principle and performance the feasibility of the system is verified. Finally, through the debugging tests system function and put forward some improved measures to the existing problems.