非理想同步下BCH码盲识别的改进算法

为实现信道差错概率未知和非理想同步条件下BCH码的盲识别，本文提出了一种改进的盲识别算法。首先，结合调制方式和信噪比估计算法估计出信道差错概率；然后，根据该信道差错概率推导出一个最佳判决界，以判断测试域指数下某个最小多项式是否为生成多项式的因式，完成码长的识别；最后，比较各测试同步偏差下全部行多项式中被最小多项式整除的个数识别出实际同步偏差，并找到满足判决界的全部最小多项式完成生成多项式的识别。仿真结果表明，在信道差错概率未知和非理想同步条件下，本文算法能够有效的完成对BCH码的识别，且识别性能优于已有算法。 

Improved Algorithm for Blind Recognition of BCH Codes Under Imperfect Synchronization

In order to realize blind recognition of BCH codes in the case of unknown channel error probability and imperfect synchronization, an improved blind recognition algorithm was proposed. Firstly, estimated channel error probability by combining modulation scheme and SNR estimation algorithm. Then, deduced an optimal decision threshold for deciding whether a minimal polynomial under the testing field index was a factor of the generator polynomial or not according to the estimated channel error probability, and completed the recognition of the code length. At last, recognized the real synchronization deviation by comparing the number that the row polynomials were divisible by the minimal polynomial under each tested synchronization deviation, and completed the recognition of the generator polynomial by finding all the minimal polynomials that satisfied the decision threshold. Simulation results demonstrate that the proposed algorithm can recognize the BCH codes efficiently in the case of unknown channel error probability and imperfect synchronization, and the recognition performance outperforms the previous algorithms.