去蜂窝大规模MIMO-NOMA系统能效优化算法

Energy Efficiency Optimization Algorithm for Cell-Free Massive MIMO-NOMA Systems

针对去蜂窝大规模多输入多输出(Multiple-Input Multiple-Output,MIMO)非正交多址接入(Non-Orthogonal Multiple Access,NOMA)系统能耗较大的问题,提出一种兼顾功率消耗和用户服务质量的能效优化算法.首先建立下行链路总能效最大化的资源分配模型,将该非凸能效优化问题分解为用户分组和功率分配两个子问题,然后利用统计学理论提出最大化信道增益差与最小化信道相关度的用户分组算法.基于分组结果,利用连续凸近似法将原非凸功率分配子问题转化为凸优化问题,求解得到最优的功率分配因子.仿真结果表明,与传统的正交多址接入系统相比,应用所提算法的NOMA系统可以获得更高的能效性能和用户吞吐量性能,同时有效提升用户公平性.

Aiming at the problem of high energy consumption for non-orthogonal multiple access(NOMA)based cell-free massive multiple-input multiple-output(MIMO)system,a energy efficiency optimization algorithm considering both power consumption and users'quality of service is proposed.A total downlink energy efficiency maximization re⁃source allocation model is formulated,the non-convex energy efficiency optimization problem is decomposed into two subproblems of user grouping and power allocation,and the user grouping algorithm that maximizes the channel gain differ⁃ence and minimizes the channel correlation is proposed by using the statistical theory.Based on the grouping result,the nonconvex power allocation sub-problem is transformed into a convex one by using the successive convex approximation(SCA)method.Simulation results show that,NOMA system with the proposed algorithm can obtain higher energy efficien⁃cy performance and user throughput performance compared with traditional orthogonal multiple access(OMA)system,and effectively improve user fairness.