A Study On Fast Arithmetic Of Underwater Spread Spectrum Communication

In the human society, communication is not only the most common but also the most important way to interchange the information. With the development of information technology and internet, net communication, satellite communication, all kinds of conference call and in some special conditions, like underwater acoustic communication demand it more reliable and can keep secret and be low probability of interception. Because of the effect of multipath and Doppler shift, the signals through the channel fade rapidly. Especially in the shallow sea, the character is more distinctive. The traditional adaptive equalization technique may not be able to compensate the changes brought by the underwater channel. Thus, I lucubrate the arithmetic of the underwater spread spectrum communication to solve these problems. The system adopts the technique of direct sequence spread spectrum (DSSS). My work list as the following several points:In this paper, emphasis is the theory of the spread spectrum technique, especially in some details for application. I have simulated the m sequence and the corresponding arithmetic in the personal computer. The advantages of the arithmetic are got through the outcome of the simulation.Reed-Solomon code is adopted in the system and the coding and decoding programs are realized here. The executive time of the programs are dramaticallyshorted by searching the root of the equation and applying the iterative arithmetic. Introduce the characters of FPGA and VHSIC hardware description language, design the fast Walsh-Hadamard transfer on the EPF10K30 chip, analyze the problems brought by the improper parts of the program design and give the solution.