Serial interpretation method for low density parity check code

Abstract

The invention provides a serial decoding method for low-density even-odd check code based on serial message schedule decoding algorithm; message weighting average method is adopted to update the message schedule from variable node to check node, namely when the message schedule from variable node to check point is updated each time, the check node message in last time and the current calculated check node message are weighed and summed to be used as the latest message of the current check node. The invention reduces the influence on normal BP message schedule due to message weighting average, effectively inhibits bit LLR value oscillation and improves the decoding performance; meanwhile, the decoding algorithm has lower decoding complexity.

Description

technical field [0001] The invention belongs to the decoding method of low-density parity-check codes in the communication field, and in particular relates to a serial decoding method of low-density parity-check codes. technical background [0002] Low-Density Parity-Check (LDPC, Low-Density Parity-Check) codes are usually decoded using a belief-propagation (BP, belief-propagation) algorithm. The algorithm can realize maximum likelihood decoding on the acyclic factor graph. On the circular factor graph, although the BP algorithm cannot accurately calculate the decoding information to ensure the optimality of decoding, it can still obtain better decoding performance. . For LDPC codes with medium and short lengths, due to the influence of short loops on the factor graph, some bit log-likelihood ratio (LLR, Log-Likelihood-Ratio) values ​​will oscillate during BP decoding, thereby reducing the decoding performance. S.H.Lee et al. studied the three types of bit message changes...

AI Technical Summary

Problems solved by technology

[0028] For short and medium length LDPC codes in the BP decoding process, due to the existence of short loops, the variable nodes in the loop get more information from other variable nodes in the same loop, and only a small number of variable nodes from outside the loop, so that It may cause cyclic oscillation of variable node messages in the ring

Once the variable node message oscillation occurs, even if the number of iterative decoding is increased, it cannot be decoded successfully, thus reducing the performance of BP decoding

For different code structures, different code lengths and different signal-to-noise ratios, the degree of degradation of decoding performance caused by bit LLR value oscillation is different, so it is necessary to improve the decoding method

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