一种基于混合NOMA的IRS-MEC系统能量效率优化方案  

Energy efficiency optimization scheme of IRS-MEC system based on hybrid NOMA

作　　者：赵宇[1] 唐冬[1] 周发升 赵赛 黄高飞[1] Zhao Yu;Tang Dong;Zhou Fasheng;Zhao Sai;Huang Gaofei(School of Electronics&Communication Engineering,Guangzhou University,Guangzhou 510006,China)

机构地区：[1]广州大学电子与通信工程学院,广州510006

出　　处：《计算机应用研究》2023年第2期544-548,560,共6页Application Research of Computers

基　　金：国家自然科学基金资助项目(61902084,61872098);国家重点研发计划资助项目(2021YFB2012403);广东省自然科学基金资助项目(2021A1515011812);广州市重点创新创业平台项目(2020PT104)

摘　　要：在移动边缘计算系统(MEC)中结合智能反射面(IRS)和资源分配策略以提高系统能量效率是当前国内外研究的热点。基于混合非正交多址(NOMA)传输模式,通过对用户的本地运算频率、传输功率、传输时间和智能反射面离散相移的联合优化,实现智能反射面辅助的移动边缘计算系统能量效率最大化。由于优化过程涉及难以求解的非凸分式规划问题,提出了Dinkelbach-SCA的两步迭代算法:首先利用Dinkelbach方法将初始问题转换成易于求解的形式,通过分离变量对智能反射面离散相移进行优化;其次为了解耦传输功率与时间之间的耦合关系,引入辅助变量,并结合逐次凸逼近(SCA)方法将非凸问题转换成凸问题,求出优化解。仿真结果表明采用的系统方案的能量效率优于其他对比方案,并发现系统的能量效率随用户2的最小计算数据量减少而提升。In MEC combining IRS and resource allocation strategies to improve system energy efficiency is a current hot topic of research at home and abroad.This paper aimed to maximize energy efficiency in IRS-assisted MEC system through joint optimization of the computing frequency at users,transmit power and time,and the IRS discrete phase-shift based on the transmission mode of hybrid non-orthogonal multiple access.Since the optimization process involved non-convex fractional programming problems that are difficult to solve,this paper proposed a Dinkelbach-SCA algorithm with two iterative-steps.Firstly,this paper converted the initial problem into a tractable form via Dinkelbach’s method,optimization of IRS discrete phase shift by separating variables.Then,by introducing auxiliary variables,and leveraging successive convex approximation,the paper decoupled the relationship between transmit power and time while converted the non-convex problem to a convex one.Hence,the paper could obtain optimal solution.The simulation results show that the energy efficiency of the proposed system scheme is better than other comparison ones,and the energy efficiency of the system increases with the decrease of the minimum computational data amount of user 2.

关 键 词：智能反射面 能量效率 混合NOMA 移动边缘运算 资源分配 

分 类 号：TP393.04[自动化与计算机技术—计算机应用技术]