Study On Serial Concatenated Coding Technology In Underwater Acoustics Communication

Ocean channel is such a complex environment that it varies in space, time and frequency. Narrow band, multipath and fading are the three main obstacles in reliable high data rate communication. How to transmit information reliably and in high data rate in underwater environment is a hot topic. Besides advanced modulation and demodulation and channel equalization techniques etc., underwater acoustic communication must use error-correcting coding whose capability is good to ensure the reliability of information transmission and reduce bit error rate. The serial concatenated code which contains two short codes is an excellent channel code whose efficiency is closed to Shannon bounds. It has good performance of correcting random and burst error and combined error with random and burst error without adding coding and computing complexity. In this paper, according to the characteristics of underwater acoustic channel, statistical feature, characteristics of channel error and the performance requirement of communication system, the principle and structure and capability of serial concatenated code are studied in detail. The capability which interleaver deal with burst error is studied, an error-correcting coding applied in underwater acoustic communication is built up. The method is verified to be reliable and applicable by simulation and lake experiments.Main research and achievements are summarized as follows:1. The characteristics of underwater acoustic channel, statistical feature and characteristics of channel error are studied. The study show that underwater acoustic channel is a memorial channel in which random errors and burst errors occur simultaneously and dense burst errors predominate in most of time.This gives the theory foundation of how to design error-correcting code in the underwater acoustic communication system.2. The principle and performance and arithmetic of coding and decoding of RS code and convolutional code and serial RS concatenated convolutional code are studied. The results show that RS code has the ability of dealing with burst errors and convolutional code can use relativity of codes, so the length of coding increase comparatively and Viterbi soft-decision decoding can obtain 2dB coding gain than hard-decision decoding.3. According to the characteristics of underwater acoustic channel, the principle...