A combined source-channel decoding method for underwater acoustic communication

Abstract

The invention discloses an underwater acoustic communication information source channel joint decoding method, which comprises the following steps: acquiring information data sent by an encoding end,demodulating the information data, and determining a receiving symbol sequence and an information source contribution degree, the information source contribution degree being a ratio of redundancy ofa sending information source sequence to a redundancy mean value; generating a joint decoding tree by utilizing a recursive chaos model according to the encoding parameters of the encoding end, and calculating a part of encoding symbol sequences corresponding to each branch in the decoding tree and a part of information sequences corresponding to decoding paths in the decoding tree layer by layer;calculating a branch metric value of eac information sequence of the decoding tree by adopting an information source channel joint maximum posteriori probability criterion and combining noise energy,information source prior information, the information source contribution degree and the receiving symbol sequence; and calculating a path metric sum value corresponding to each branch in the decoding tree, and selecting the branch corresponding to the maximum path metric sum value to obtain a decoding information sequence. According to the method, the correlation between signal source symbols isfully utilized, channel decoding is corrected, and the decoding performance of underwater acoustic communication is improved.

Description

technical field [0001] The present application relates to the technical field of underwater acoustic communication, and in particular, relates to a joint decoding method of information sources and channels of underwater acoustic communication. Background technique [0002] In a traditional underwater acoustic communication system, the sending end performs source coding and channel coding on the sending source sequence successively, and sends it to the receiving end. Estimation of source sequence correspondence. [0003] Moreover, due to the characteristics of the underwater acoustic communication system, in actual underwater acoustic communication, there is usually a certain correlation between the source symbols in the transmitted source sequence. When a source symbol A is determined, the source symbol set The probability that each source symbol appears as a subsequent symbol of source symbol A presents a certain regular distribution, and the distribution depends on the va...

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Problems solved by technology

However, these two decoding methods, on the one hand, are difficult to be practically applied due to the high complexity of the algorithm when dealing with a large set of source symbols.

[0005] On the other hand, due to the difference in the size of the correlation redundancy contained in the actual source sequence sent, the above two methods cannot adjust the proportion of the source prior information in the decoding process, and it is difficult for all possible source sequences to be transmitted. Guaranteed performance of the joint decoding method

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