Identification method of code parameter of BCH (broadcast channel) shortened code

Abstract

The invention discloses an identification method of a code parameter of a BCH (broadcast channel) shortened code. The identification method comprises the following steps of: analyzing a frame structure of a message bit stream and determining a grouping starting point of the BCH shortened code; taking a code group serial number N, taking a fixed m on a GF (generator field) (2<m>), and selecting an m-order primitive polynomial; carrying out code length nd traverse in a sustaining code length range, supplementing 2<m>-1-nd 0 to the front of each code word, and finishing a non-shortened code of a BCH shortened code word; calculating a corresponding fiducial probability value P corresponding to the selected m and the code length n; for the selected significance level alpha, if P is larger than or equal to alpha, judging the m and nd as an actual coding parameter; determining the code length at the range of 0-(n-1) code root, and calculating the probability of each code root, wherein the probability of the code root is greater than 0.9 in each code group root, and a polynomial g(x) root is generated; determining m-order primitive polynomial as a foundation, and determining the generating polynomial g(x) of the BCH shortened code; and obtaining a message bit length kd of the BCH shortened code from the order number nd-kd of the generating polynomial of the BCH shortened code in combination with the code length nd.

Description

technical field [0001] The invention relates to the communication field, in particular to a method for identifying encoding parameters of a BCH shortening code. Background technique [0002] The parameter identification of the BCH code is to estimate the coding parameters, that is, the code length, the information bit length, and the polynomial parameters by processing and analyzing the coded bit stream sequence when only the BCH code code sequence is given, so as to facilitate the subsequent Protocol analysis and information recovery. [0003] Yang Xiaojing and Wen Niancheng proposed a better method based on code root difference in the article "BCH code identification method based on code root information difference entropy and code root statistics" in "Journal of Detection and Control" Volume 32 Issue 3 in 2010. Entropy parameter identification method, this method first uses the defined code root difference entropy function to identify the BCH code length, and then uses t...

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Problems solved by technology

[0005] Although the above studies are identifying (n,k)BCH codes (n=2 m -1) The parameters have a good effect, but for the (n-i, k-i) BCH shortening code (i is the number of reduced symbols) that is often applied in actual engineering, the above research does not provide a solution

In addition, for the identification of the code length, the qualitative identification method of finding the maximum value of the code root difference entropy function is adopted in the above research. The generator polynomial is obtained by performing finite field multiplication on the obtained code root. The calculation process is complicated and The amount is large, which is not conducive to computer realization

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