Resource Allocation for Multi-Cell IRS-Aided NOMA Networks
Resource Allocation for Multi-Cell IRS-Aided NOMA Networks
复制标题
DOI：
10.1109/twc.2021.3057232
复制
发表时间：
2021-07-01
影响因子：
10.4
通讯作者：
Chen, Yue
中科院分区：
文献类型：
--
作者：
Ni, Wanli;Liu, Xiao;Chen, Yue
本文提出了一种新的资源分配框架，在多小区智能反射面（IRS）辅助非正交多址接入（NOMA）网络，IRS部署，以提高无线服务。联合用户关联，子信道分配，功率分配，相移设计和解码顺序确定的问题制定最大化可实现的和速率。将具有挑战性的混合整数非线性问题分解为连续变量的优化子问题（P1）和整数变量的匹配子问题（P2）。为了解决非凸优化问题（P1），提出了利用凸上界替换、逐次凸逼近和半定松弛等松弛方法来分配发射功率、设计反射矩阵和确定译码顺序的迭代算法。根据组合问题（P2），提出了基于交换匹配的算法，以实现用户、基站和子信道之间的双边交换稳定状态。数值结果表明：（1）IRS的引入使多小区NOMA网络的总速率提高了35%;（2）与传统NOMA网络相比，本文提出的多小区IRS辅助NOMA网络算法的能量效率提高了22%;（3）IRS的位置选择可以在频谱效率和覆盖面积之间进行权衡.
This article proposes a novel framework of resource allocation in multi-cell intelligent reflecting surface (IRS) aided non-orthogonal multiple access (NOMA) networks, where an IRS is deployed to enhance the wireless service. The problem of joint user association, subchannel assignment, power allocation, phase shifts design, and decoding order determination is formulated for maximizing the achievable sum rate. The challenging mixed-integer non-linear problem is decomposed into an optimization subproblem (P1) with continuous variables and a matching subproblem (P2) with integer variables. In an effort to tackle the non-convex optimization problem (P1), iterative algorithms are proposed for allocating transmission power, designing reflection matrix, and determining decoding order by invoking relaxation methods such as convex upper bound substitution, successive convex approximation, and semidefinite relaxation. In terms of the combinational problem (P2), swap matching-based algorithms are developed for achieving a two-sided exchange-stable state among users, BSs and subchannels. Numerical results demonstrate that: i) the sum rate of multi-cell NOMA networks is capable of being increased by 35% with the aid of the IRS; ii) the proposed algorithms for multi-cell IRS-aided NOMA networks can enjoy 22% higher energy efficiency than conventional NOMA counterparts; iii) the trade-off between spectrum efficiency and coverage area can be tuned by judiciously selecting the location of the IRS.