The fundamental intelligent reflecting surface (IRS) deployment problem is investigated for IRS-assisted networks, where one IRS is arranged to be deployed in a specific region for assisting the communication between an access point (AP) and multiple users. Specifically, three multiple access schemes are considered, namely non-orthogonal multiple access (NOMA), frequency division multiple access (FDMA), and time division multiple access (TDMA). The weighted sum rate maximization problem for joint optimization of the deployment location and the reflection coefficients of the IRS as well as the power allocation at the AP is formulated. The non-convex optimization problems obtained for NOMA and FDMA are solved by employing monotonic optimization and semidefinite relaxation to find a performance upper bound. The problem obtained for TDMA is optimally solved by leveraging the time-selective nature of the IRS. Furthermore, for all three multiple access schemes, low-complexity suboptimal algorithms are developed by exploiting alternating optimization and successive convex approximation techniques, where a local region optimization method is applied for optimizing the IRS deployment location. Numerical results are provided to show that: 1) near-optimal performance can be achieved by the proposed suboptimal algorithms; 2) asymmetric and symmetric IRS deployment strategies are preferable for NOMA and FDMA/TDMA, respectively; 3) the performance gain achieved with IRS can be significantly improved by optimizing the deployment location.

中文翻译：

---

智能反射面辅助网络的联合部署和多址设计

研究了 IRS 辅助网络的基本智能反射面 (IRS) 部署问题，其中一个 IRS 被安排部署在特定区域以辅助接入点 (AP) 和多个用户之间的通信。具体地，考虑了三种多址方案，即非正交多址(NOMA)、频分多址(FDMA)和时分多址(TDMA)。制定了用于联合优化部署位置和 IRS 反射系数以及 AP 功率分配的加权和速率最大化问题。NOMA 和 FDMA 的非凸优化问题是通过采用单调优化和半定松弛找到性能上限来解决的。IRS 的时间选择性。此外，对于所有三种多址方案，通过利用交替优化和连续凸逼近技术开发了低复杂度次优算法，其中局部区域优化方法用于优化IRS部署位置。提供的数值结果表明：1）所提出的次优算法可以实现接近最优的性能；2)不对称和 对称 IRS 部署策略分别适用于 NOMA 和 FDMA/TDMA；3) 通过优化部署位置，可以显着提高 IRS 实现的性能增益。