论文标题
多群体IRS-NOMA网络中波束形成，相移和功率分配的联合优化
Joint Optimization of Beamforming, Phase-Shifting and Power Allocation in a Multi-cluster IRS-NOMA Network
论文作者
论文摘要
非正交多重访问（NOMA）和智能反射表面（IRS）的组合是显着提高无线通信系统能源效率的有效解决方案。在本文中，我们关注一个下行链路多群体NOMA网络，在该网络中，每个集群都由一个IRS支持。我们的目标是通过共同优化每个IRS的波束形成，功率分配和相移来最大程度地减少发射功率。该法式问题是由于耦合变量，即射击向量，功率分配系数和相移矩阵而解决的非凸面和挑战。为了解决这个非凸问题，我们提出了一种基于优化的算法。具体而言，我们将原始问题划分为两个子问题，以进行波束形成优化和相位转移的偏见，其中两个子问题迭代解决。此外，为了确保波束形成优化问题的可行性，提出了迭代算法来搜索可行的初始点。为了降低复杂性，我们还基于对该系统模型的部分详尽搜索提出了一种简化的算法。模拟结果表明，所提出的交替算法比具有随机IRS相移的部分详尽搜索算法，OMA-IRS和NOMA可以产生更好的性能增长。
The combination of non-orthogonal multiple access (NOMA) and intelligent reflecting surface (IRS) is an efficient solution to significantly enhance the energy efficiency of the wireless communication system. In this paper, we focus on a downlink multi-cluster NOMA network, where each cluster is supported by one IRS. We aim to minimize the transmit power by jointly optimizing the beamforming, the power allocation and the phase shift of each IRS. The formulated problem is non-convex and challenging to solve due to the coupled variables, i.e., the beamforming vector, the power allocation coefficient and the phase shift matrix. To address this non-convex problem, we propose an alternating optimization based algorithm. Specifically, we divide the primal problem into the two subproblems for beamforming optimization and phase shifting feasiblity, where the two subproblems are solved iteratively. Moreover, to guarantee the feasibility of the beamforming optimization problem, an iterative algorithm is proposed to search the feasible initial points. To reduce the complexity, we also propose a simplified algorithm based on partial exhaustive search for this system model. Simulation results demonstrate that the proposed alternating algorithm can yield a better performance gain than the partial exhaustive search algorithm, OMA-IRS, and NOMA with random IRS phase shift.
