Low-complexity joint source-channel encoding and decoding method based on space lattice diagram

Abstract

The invention relates to a low-complexity joint source-channel encoding and decoding method based on a space lattice diagram. In a low-complexity joint source-channel encoding and decoding system based on the space lattice diagram, each symbol in an information source assembly is endowed with a weight (named a symbol weight) in probability correlation with the symbol. At the encoding end, the symbol sequence has three constraint values, namely an accumulated symbol number, an accumulated bit number and an accumulated symbol weight, after being subjected to variable-length encoding. At the decoding end, the three constraint values are utilized to construct the space lattice diagram, the three-dimensional coordinates of the space lattice diagram respectively signify 'symbol number index', 'bit status index' and 'weight status index'. A redundant status transfer path on the space lattice diagram is removed firstly, then status nodes and status transfer branches on the space lattice diagram are projected on a two-dimensional plane to generate a simplified variable-length information source code lattice diagram, and the symbol-level maximum posterior probability decoding algorithm is adopted to realize the low-complexity joint source-channel encoding and decoding method.

Description

technical field [0001] The invention relates to a joint source-channel codec method in the field of communication codec, in particular to a low-complexity joint source-channel codec method based on a space grid graph. Background technique [0002] In the current communication system, Shannon's "Separation Theory" is generally followed, that is, source coding and channel coding are independently optimized and designed, so that the communication system can obtain the best coding performance. However, the premise of "separation theory" is: regardless of source coding or channel coding, it is assumed that an infinite delay can be tolerated (allowing the coding block to be infinitely long); the statistical characteristics of the transmission channel are known in advance. In reality, the constraints of codec complexity, hardware and software resources, and communication delay make the actual communication system unable to meet this condition, and the source coding and channel codi...

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Problems solved by technology

[0005] In order to solve the problem of many state transition branches and high computational complexity in the traditional variable-length signal source code planar grid graph, the present invention proposes a space-based A low-complexity joint source-channel encoding and decoding method for grid graphs. This method designs a construction method for spatial grid graphs and a corresponding encoding and decoding method

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