提高多址接入性能的功率与LDPC码的优化设计  

Design Optimization for Multiple Access via Power and LDPC Code

作　　者：张京席[1,2] 别志松[1] 吴伟陵[1] 

机构地区：[1]北京邮电大学信息与通信工程学院,北京100876 [2]华北电力大学电子系,河北保定071053

出　　处：《北京邮电大学学报》2011年第4期56-60,共5页Journal of Beijing University of Posts and Telecommunications

基　　金：国家自然科学基金项目(60902048);国家重点基础研究发展计划项目(2007CB310604);中央高校基本科研业务费资助项目(BUPT2011RC0109);国家科技重大专项项目(2008ZX03003-005;2010ZX03003-003-01)

摘　　要：为了逼近多址接入信道的容量限,对功率与低密度校验阵(LDPC)码的度分布进行了优化.基于互信息最大化准则设计了功率分配算法,并得出分配方案,利用高斯近似来近似取得因子图上消息的概率密度函数,得到功率分配条件下优化的LDPC码的度分布.采用迭代的检测与译码算法进行多址干扰的消除.仿真结果表明,经功率和LDPC码优化后的误码性能在误码率为10-5时比等功率只优化LDPC码度分布时的性能提升了1.6 dB.A study on approach multiple access channel capacity by means of power allocation and low density parity check （LDPC） codes optimization is presented. The power allocation scheme is designed based on the maximization of mutual information and then the power profile is obtained. The probability density function of message on factor graph is obtained by Gaussian approximation. The optimized LDPC code degree profiles are obtained by using the power profile. Iterative detection and decoding algorithm is also applied to combat multiple access interference. Simulation showes that the bit error probability performance can be improved by 1.6 dB at 10^-5 with the proposed method compared with that of only optimization of LDPC code.

关 键 词：多址接入信道 低密度校验阵码 高斯近似 交织多址 功率分配 码优化 

分 类 号：TN929.53[电子电信—通信与信息系统]