非理想Nakagami-m信道下DF协作系统的最优功率分配  

Optimal power allocation of the DF cooperation system over imperfect Nakagami-m fading channels

作　　者：张南[1] 葛建华[1] 宫丰奎[1] 高明[1] 

机构地区：[1]西安电子科技大学综合业务网理论及关键技术国家重点实验室,陕西西安710071

出　　处：《西安电子科技大学学报》2012年第2期17-23,共7页Journal of Xidian University

基　　金：国家自然科学基金资助项目(61001207,61101144,61101145);国家重点基础研究发展计划资助项目(2012CB316100);长江学者和创新团队发展计划资助项目(IRT0852);中央高校基本科研业务费专项资金资助项目(K50510010008,K50511010015);高等学校学科创新引智计划资助项目(B08038)

摘　　要：针对Nakagami-m衰落信道下的多中继DF协作系统,研究信道估计误差存在时功率分配对系统性能的影响.首先基于全概率公式和矩母函数(MGF)方法,给出M-QAM调制下的近似误符号率(SER)和渐进SER解析式;其次,基于简洁的渐进解析式,将功率分配问题转换为典型的凸优化求解问题.得出了在总功率一定的条件下,最小化系统SER的最优功率分配的理论计算公式.计算机仿真结果表明:信道估计误差存在时,相比较等功率分配策略,最优功率分配能显著提高中低信噪比下的协作系统性能,但不能改善高信噪比下系统的错误平层.The impacts of power allocation under imperfect channel estimation on the symbol-error-rate（SER） are investigated for a cooperative network with multiple decode-and-forward（DF） relays over Nakagami-m fading.First,the approximate SER and asymptotic SER for M-QAM are provided by using the Theorem of Total Probability and the moment generating function（MGF）.Then based on the presented compact asymptotic SER,the optimal power allocation is transformed to a typical convex optimization problem so that the optimal power allocation is reached to minimize the SER under the total power constraints.Simulations show that compared to the uniform allocation scheme,optimal power allocation scheme can significantly improve the performance of the cooperative system at the low to medium SNR,but can not improve the error floor at the high SNR under the imperfect channel estimation.

关 键 词：协作通信 译码转发 M-QAM 信道估计误差 误符号率 功率分配 

分 类 号：TN911[电子电信—通信与信息系统]