Effect of low-weight seed sequences on low-code redistribution of Turbo codes

Turbo code;  code weight distribution;  Interlogators

The probability of seed sequences of different weights remaining seed sequences after interweaving was analyzed by probabilistic method, and the influence of low-weight seed input sequences on the low-code redistribution of Turbo codes was discussed. Through analysis and discussion, it is pointed out that if the period of feedback polynomial in the Turbo code generation polynomial is longer, the weight of the codeword generated by the heavy 2 input sequence will be larger, while the weight of other weight seed input sequences, especially the seed input sequence with weight 3 and 4, the weight of the code word produced is likely to be lower than that of the weight of the code word generated by the heavy 2 input sequence. The shorter the length of the interleaver, the greater the probability of this happening.