LT码度分布改进及在认知无线电链路保持中的应用

摘要

度分布是影响Luby transform(LT)码性能的关键因素.基于认知无线电链路保持模型,采用双层寻优算法(THOA, two-layer hierarchical optimization algorithm),将译码开销较小时具有高译码成功率的改进的泊松分布(IPD, improved Poisson distribution)与译码开销较大时具有高译码成功率的顽健孤子分布(RSD, robust soliton distribution)的优点进行有机结合,构建新型LT码度分布.仿真结果表明,该新型度分布应用于基于LT码的认知无线电链路保持中,能有效提高次用户通信可靠性和有效性.%The degree distribution has a great influence on the performance of Luby transform (LT) codes. Based on the link maintain model of cognitive radio system,the novel degree distribution of LT codes was obtained by using the THOA (two-layer hierarchical optimization algorithm) to combine the IPD (improved poisson distribution) which achieved high decoding success rate with low overhead and the robust soliton distribution (RSD) which achieved high decoding success rate with high overhead. Simulation results show that the proposed method with application to link maintenance in cognitive radio system can improve the reliability and efficiency of secondary communication.