论文标题
IRS辅助上行链路NOMA的总和率最大化
Sum Rate Maximization for IRS-assisted Uplink NOMA
论文作者
论文摘要
智能反射表面（IRS）由大量的低成本反射元素组成，可以通过被动光束形成来协同指导入射信号。这样，IRS会重新配置无线环境以提高系统性能。在本文中，我们考虑了IRS辅助上行链路非正交多访问（NOMA）系统。目的是最大化所有用户在个人功率约束下的总和率。所考虑的问题需要在用户处进行联合功率控制，并在IRS处进行横梁成形设计，并且是非convex。为了处理它，采用了半决赛松弛，提供了近乎最佳的解决方案。提出的数值结果表明，所提出的基于NOMA的方案的总和速率比基于正交的多访问（OMA）的总和更高。此外，揭示了反射元素数量对总和率的影响。
An intelligent reflecting surface (IRS) consists of a large number of low-cost reflecting elements, which can steer the incident signal collaboratively by passive beamforming. This way, IRS reconfigures the wireless environment to boost the system performance. In this paper, we consider an IRS-assisted uplink non-orthogonal multiple access (NOMA) system. The objective is to maximize the sum rate of all users under individual power constraint. The considered problem requires a joint power control at the users and beamforming design at the IRS, and is nonconvex. To handle it, semidefinite relaxation is employed, which provides a near-optimal solution. Presented numerical results show that the proposed NOMA-based scheme achieves a larger sum rate than orthogonal multiple access (OMA)-based one. Moreover, the impact of the number of reflecting elements on the sum rate is revealed.
