一种LT码编码生成矩阵的伪随机产生方案

常用的LT码编码生成矩阵的传输方案是在每个编码数据包的头部额外增加一个开销,用于放置该数据包对应的编码生成矢量.该方案会产生较大的开销,造成传输效率降低.给出了一种编码生成矩阵在编码器和译码器间伪随机同步产生的方案.采用该方案时,只要编码器和译码器伪随机数发生器的算法相同,种子也相同,就能产生一样的均匀伪随机数序列,将其进行转化后就能得到相同的编码生成矩阵.种子数据量小,且只需要在伪随机数发生器初始化时编码器和译码器间交换一次即可.实验结果显示,生成的伪随机度值符合指定的度分布函数,数据包的伪随机选择也符合泊松分布.相比较传统方案,该方案避免了编码生成矩阵的直接传输,减少了传输开销,提高了传输效率.

A pseudo-random scheme to generate the generator matrix of LT codes

The generator vector of LT codes is transmitted by using an overhead in the header of each encoded packet to place code generation vector correspondingly in the traditional scheme.This scheme brings a large overhead, which causes the decline of transmission efficiency. Based on this, a pseudo-random generation scheme is given in this paper, which generates the generator matrix at encoder and decoder synchronously. The generator matrices generated in this way will be identical to each other, as long as the encoder and decoder use the same pseudo-random generator and the same seed. The seed is small data-wise, and it only needs to be exchanged once between the encoder and decoder when the pseudo-random generators are initialized. Experimental results show that the generated pseudo-random values are in accordance with the specified degree distribution, and the pseudo-random indices of source packets for encoding obey Poisson distribution values. Compared with traditional methods, this scheme avoids direct transmission of the generator matrix, which can reduce transmission cost and improve transmission efficiency.