Degree distribution optimization method and coding and decoding method of system LT codes under erasure channel

Abstract

The invention discloses a degree distribution optimization method and a coding and decoding method of system LT codes under an erasure channel, and belongs to the technical field of digital communication. According to the invention, a degree distribution optimization model is determined by a system LT code asymptotic performance recursion formula; the coding method is characterized in that after any degree is randomly selected in a degree distribution optimization result, different data symbols identical with the selected degree value are selected from original data symbols, and coding data symbols are obtained by the different data symbols; the decoding method is characterized in that a bipartite graph is established according to the corresponding relation between the coding data symbols and the original data symbols, the coding data symbol with a degree of 1 is searched, the corresponding original data symbol is directly recovered, and the recovered original data symbols and edges connected with the recovered original data symbols are deleted in the bipartite graph. The theory performance of the system LT codes under the erasure channel can be conveniently calculated by the asymptotic performance recursion formula, and relatively good bit error rate performance is provided by the optimization result.

Description

technical field [0001] The invention discloses a degree distribution optimization method and a coding and decoding method of a system LT code under an erasure channel, and belongs to the technical field of digital communication. Background technique [0002] Because of its simplicity and easy theoretical analysis, the deleted channel is a channel model commonly used in coding theory and information theory. In the deletion channel, when the sending end sends a data packet (bit sequence of 0, 1), the receiving end can either receive the data packet correctly, or receive the information that the data packet is deleted. figure 1 A model of such a channel is given, where p is the deletion probability of deleting the channel. In order to solve the problem of data packet loss in the erasure channel, ARQ (Automatic Repeat reQuest, automatic repeat request) technology is widely used. If the channel condition becomes worse, that is, more data packets are deleted, the frequency of re...

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Problems solved by technology

[0030] The technical problem to be solved by the present invention is to aim at the deficiency of the above-mentioned background technology, provide a degree distribution optimization method and a coding method of the system LT code under the deletion channel, and propose a degree distribution optimization based on the progressive performance recursive formula of the system LT code scheme, and based on the degree distribution optimization scheme, the compilation method of the system LT code is given, which solves the technical problem that the traditional LT code degree distribution cannot provide good bit error rate performance for the system LT code

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