Optimal Designing of Degree Distribution of AR Code in Collaborative Network

Channel coding with fixed rate in large-scale network communication has poor adaptability, which greatly affects the reliability of information transmission. In order to solve this problem, this paper proposed the cooperative transmission mechanism in Accumulate Rateless Code (AR Code). Then it made an overall analysis of soft information iterative decoding model with extrinsic information transfer (EXIT) chart, and designed the scheme of joint optimization of degree distribution of AR Code for the goals of maximizing the code rate. And three kinds of solution strategies was given. The method solved the problem of degree distribution optimization of AR code in collaborative network. The theoretical analysis and simulation results have shown that the degree distribution of AR code gave by our method is better than that of classical degree distribution of LT codes and the degree of existing AR code distribution optimization results in decoding performance. It can reduce the error floor below 10^-6, and get a 6.25% reduction of the reciprocals of code rate at least. Meanwhile, the cooperative transmission scheme based on AR code has the very good adaptive characteristics, and improves the network transmission performance of low signal to noise ratio (SNR).