A Coding Identification Algorithm for code length and code rate of LDPC

In the channel coding identification system, in view of the low recognition rate of LDPC code parameters under low signal-to-noise ratio(SNR) environment, this paper proposes a coding identification algorithm for code length and code rate of LDPC codes. The algorithm uses the soft information of the channel output, establishes the relationship between coding parity relation and domain of the log-likelihood ratio, and uses the maximum mean square ratio (MSR) decision maker to recognize the finite set of LDPC. This algorithm makes full use of the statistical characteristics of the mean and variance of data, and effectively avoids the defect that the traditional algorithm is not ideal when the SNR is low. Moreover, for LDPC codes with high bit rate, the discrimination of the MSR judgment is very obvious, which can achieve a better recognition effect. Experimental results show that compared with existing algorithms, the proposed algorithm can still achieve better recognition results in low SNR environment, and the recognition gain can reach 2 dB to 5 dB. And when the SNR is higher than 5dB, the correct rate can reach 99%. For the recognition of high bit rate LDPC codes, the recognition effect of this algorithm is much better than that of the existing algorithm.