Abstract: LT codes can effectively transfer information over erasure channel with unknown erasure rates due to their rateless properties. The cost of LT codes decoding is increasing with the probability of R-set with empty. This paper introduces an improved method of LT codes encoding and decoding which changes the degrees of input symbols, while the degrees of input symbols are according to uniform distribution and 4-cycle is eliminated. The algorithm can decrease the probability of R-set with empty. Simulation results show that the method can reduce the cost of LT codes decoding.

Key words: LT codes, erasure channel, R-set

摘要： LT码的无速率特性使其可在删除率未知的删除信道下高效传输信息，但译码代价会因R集合为空集概率的增加而增加。针对该问题，提出一种LT码编译的改进方法，使信息单元的度数近似服从均匀分布，并去除生成矩阵中出现长度为4的短环，从而降低R集合为空集的概率。仿真结果验证，采用该方法能降低LT码的译码代价。

关键词: LT码, 删除信道, R集合

CLC Number: 

• TP391