基于极限条件的VFLLT码系统设计与性能研究

DESIGN AND PERFORMANCE STUDY ON LIMITING CONDITION-BASED VFLLT CODE SYSTEM

针对LT(Luby Transform)码的编码效率不高、时延长且译码概率低等弊端,将数学极限分析方法引入到LT码的度数分布中,提出了一种不定帧长LT码VFLLT(variable frame length LT)编译码系统方案,其核心思想是将原始数据进行适当的帧长设计,通过不定帧长的方法对原始数据进行拆分编译码。在理论推导过程中,详细分析了该不定帧长LT码设计方法的编译码复杂度和平均度数。理论分析和仿真结果表明:与传统LT码相比,不定帧长LT码能够有效地提高编码效率和译码概率,降低其编译码运算量和度数分布值,增强了LT码在实际系统应用时的可行性。

LT code has the drawbacks of low encoding efficiency,long latency and poor decoding probability.To address the above issues,the mathematical limit analysis method is introduced into the degree distribution of LT code,and an encoding system scheme with variable frame length LT code is proposed,whose core idea is to make an appropriate design on the frame length of primitive data,and to encode by separating the primitive data with variable frame length method.In the process of theoretical deduction,the encoding complexity and average degree of the variable frame length LT codes designing approach are elaborately analysed.Theoretical analysis and simulation results show that,compared with conventional LT codes,the variable frame length LT codes can effectively improve the encoding efficiency and decoding probability,reduce the encoding and decoding computation and the degree distribution,and enhance the feasibility of LT code in actual system application.