The Research Of Underwater Acoustic Communication Based-on OFDM

It is demanding of exploiting the ocean that propels the development of underwater acoustic communication technology.However,underwater acoustic communication is at initial stage.The reverberation and the Doppler-spread are two main prominent characteristics of the underwater acoustic channels for communication. In the result of that,the exploitation of underwater acoustic communications must be attained in view of the characteristics of their own.Orthogonal Frequency Division Multiplex(OFDM)is a new technology that transmits data in at a high speed on wireless channel,It belongs to multi-carriers modulating technology,and its most remarkable character is the high-speed transmitting ability as well as the excellent resistibility to interface of signal interval and decline of channel selectivity.Therefore,it must be of good theoretical and practical value to conduct research on acoustic communication based on OFDM.This paper takes this one as the background,have carried on studying of and designing a underwater acoustic communications transmitter subsystem Based-on OFDM Technology. The main content in this paper are as follows:1. The article gives a brief introduction of underwater acoustic communication and the application of OFDM in it.It also presents a study on the principles of the OFDM technology and a OFDM communication system block diagram.2. A basic theoretical analysis about principles of the high Peak to Average power Ratio(PAR),which is one of the main defects of OFDM system,and a method is studied in this dissertation to reduce the high PAR problem:Partial Transmit Sequence(PTS).3. Hardware platform of communication system in this design applies the TMS320VC5509A chip that belongs to TMS320C5000 series made by TI to realize the OFDM modulation and other baseband signal processing, The power amplifier circuit of the this design applies the TK2350 that belongs to T-class digital audio amplifier made by Tripath Technology Inc, which offer both the audio fidelity of Class-AB and the power efficiency of Class-D amplifiers.4. Software design of communication system such as the Inverse FFT(IFFT) algorithms,bit interleaving algorithms,PTS,QPSK bit map and so on will be realized in this design.