Abstract: Over the erasure channel, the performance of the belief propagation decoding algorithm of LT codes with small message length is bad. An improved belief propagation decoding algorithm is proposed, which only uses the Gaussian elimination method to confirm a few guessing bits for realizing decoding successfully after belief propagation decoding fails. The simulation results demonstrate that, compared with the belief propagation decoding, the proposed algorithm can significantly improve the decoding performance. The cost is in some added decoding time.

Key words: fountain codes, LT codes, belief propagation decoding, binary erasure channels

摘要： 在删除信道上，短信息字长度的LT码采用置信传播译码算法性能较差。提出了一种改进的置信传播译码算法，此算法在置信传播译码失败时只需运用高斯消元法确定少数猜测比特就可实现成功译码。仿真结果显示，相比于置信传播译码，改进的置信传播译码算法在增加少量译码运行时间的代价下获得较大的译码性能改善。

关键词: 喷泉码, LT码, 置信传播译码, 二进制删除信道