LT码新型度分布及其在电力线通信中的应用

Luby变换(Luby Transform,LT)码作为信道编码应用于电力线通信(Power Line Communication,PLC)，可实现电信号的可靠传输。度分布对LT码编译码性能的影响至关重要。为了得到更优的度分布，首先调整二进制指数分布(Binary Exponential Distribution,BED)中的度数比例，获得一种译码性能更优的改进的二进制指数分布(Improved BED,IBED)。然后，根据IBED在冗余度较小时译码成功率高，而冗余度增大后鲁棒孤子分布(Robust Soliton Distribution,RSD)的译码性能表现更佳的特点，通过求和归一化的方式将IBED与RSD两种度分布的优势进行有机结合，提出一种新型二进制鲁棒孤子分布(Binary RSD,BRSD)。仿真结果表明，与其他方法及传统的RSD相比，采用新度分布进行LT编码，可明显降低译码开销，并节约编译码耗时。将新型度分布应用于基于LT码的PLC系统中，能有效地抑制PLC信道中各种噪声对电信号的干扰，并提高通信效率。

A novel degree distribution of LT codes and its application in power line communication

As a channel coding,Luby transform (LT) codes can be applied in the reliable transmission of telecommunication signal in power line communication (PLC).The degree distribution greatly influences the performance of LT codes.In order to gain a better degree distribution,an improved binary exponential distribution (IBED) with better decoding performance is obtained by adjusting the degree fractions of binary exponential distribution (BED).The decoding performance of IBED outperforms robust soliton distribution (RSD) when the overhead is small,while RSD performs better as the overhead increases.Then,binary-robust soliton distribution (BRSD) is proposed by the normalization method to combine the advantages of IBED and RSD.Simulation results show that compared with other optimized degree distributions and RSD,the new degree distribution reduces the overhead,and saves the average consuming time per encoding/decoding process.Application of BRSD in PLC can effectively restrain the interference of all kinds of noise to the telecommunication signal in the PLC channel,and improve the communication efficiency.