无线传输中短码长喷泉码的度分布优化算法

数字喷泉码是针对大规模网络数据分发而提出的一种新的信道编码方式。度分布是决定数字喷泉码译码性能的关键因素。为提高译码性能，针对应用于无线信道的喷泉码提出了一种度分布优化的算法。首先，根据理想孤子分布和鲁棒孤子分布产生度值序列，然后将该度值序列截短，在此基础上根据优化算法求解该序列中每个度值的最优概率，最后得到优化的度分布。仿真结果表明，本算法产生的度分布进行编译码产生的误码率低于鲁棒孤子分布和固定度分布，提高了译码性能。

A degree distribution optimization algorithm for small size fountain codes in wireless transmission

Digital fountain code is a popular class of erasure code,which is often used in the case of large network data transmission.The performance of Luby Transform(LT) code is mainly decided by the degree distribution.To improve the decoding performance,a degree distribution optimization algorithm is designed for wireless transmission.Firstly,based on classical soliton distribution and robust soliton distribution,the set of degree values is determined.Then the degree distribution that minimizes the number of un-recovered source symbols is found.The optimal degree distribution can be solved by evolutionary strategy.The experimental results show that compared with LT code with robust soliton distribution and the fixed degree distribution,the proposed algorithm improves the number of the recovered symbols obviously with the same overhead.