Encoder and decoder by LDPC encoding

A decoder and coding scheme technology, applied in the field of decoders and encoders, which can solve the problems of unrealistic moving objects and deterioration of characteristics.

Inactive Publication Date: 2008-07-30
NEC CORP
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Problems solved by technology

However, there is a problem that even if high performance close to the Shannon limit can be achieved, it is not realistic for a moving body
[0009] Also, a bold approximation of the Min(Max)Log region has been adopted instead of the sum-product to achieve a feasible circuit scale, but there arises a problem that this approximation causes non-negligible deterioration of characteristics

Method used

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  • Encoder and decoder by LDPC encoding
  • Encoder and decoder by LDPC encoding
  • Encoder and decoder by LDPC encoding

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Embodiment Construction

[0174] Next, before describing the embodiments of the present invention with reference to the formula and the accompanying drawings, the analysis as the background of the present invention and the analysis results of the density evolution (hereinafter abbreviated as "DE") including the Non-linear processing resulting from approximation (also known as the "minSum algorithm").

[0175] First, general DE using Gaussian approximation (hereinafter abbreviated as "GA") and DE including nonlinear processing will be described.

[0176] A normal GA is performed by tracking the mean of the LLRs to be propagated under the premise of an iterative decoding process utilizing sum-products. Specifically, for the symbol v of column weight i i , whose mean m v，i for:

[0177] [Formula 10]

[0178] m v , i = E [ v i ] = ...

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Abstract

Provided is an LDPC encoding method for realizing an error correction code encoder and decoder suitable for the communication field of mobile communication with high performance, high speed, and high efficiency. A Tanner graph for expressing codes using variable nodes and check nodes is used to classify each node into a plurality of categories. In the probability propagation calculation in iterative decoding, for the log-likelihood ratio (LLR) to be propagated, predetermined weighting for each class is performed.

Description

technical field [0001] The invention relates to a decoder and an encoder of an LDPC (Low-Density Parity-Check, Low Density Parity Check) coding scheme, and the LDPC coding scheme is an error correction coding scheme. Background technique [0002] The LDPC coding scheme was proposed by Gallager in 1962. The LDPC code refers to a linear code having a test matrix whose elements are mostly "0". In classical coding theory, test matrices are determined to design codes. A similar definition can also be made for the LDPC coding scheme derived from the turbo principle which is said to usher in a new era of coding theory. However, the present invention adopts a definition based on a Tanner diagram that captures the essence more. [0003] A Tanner graph is a two-part graph in which the code is represented by two types of nodes called variable nodes and check nodes, where the branches connected to each node are called "edges", And the number of branches connected to each node is cal...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H03M13/19
CPCH03M13/1111H03M13/1117H03M13/112H03M13/1122H03M13/1137H03M13/114H03M13/1185H03M13/3723H03M13/616H03M13/19
Inventor 丸次夫
Owner NEC CORP
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