Sum-Rate Maximization for RIS-Assisted Integrated Sensing and Communication Systems With Manifold Optimization
Sum-Rate Maximization for RIS-Assisted Integrated Sensing and Communication Systems With Manifold Optimization
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DOI：
10.1109/tcomm.2023.3277872
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发表时间：
2023-08
影响因子：
8.3
通讯作者：
Eyad Shtaiwi;Hongliang Zhang;Ahmed Abdelhadi;A. L. Swindlehurst;Zhu Han;H. Poor
中科院分区：
文献类型：
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作者：
Eyad Shtaiwi;Hongliang Zhang;Ahmed Abdelhadi;A. L. Swindlehurst;Zhu Han;H. Poor
集成传感和通信 (ISAC) 是下一代无线通信系统提高频谱效率的关键推动因素。然而，传感和通信功能的共存可能会造成有害干扰。在本文中，我们建议结合使用可重构智能表面（RIS）和 ISAC 来解决这个问题。 RIS由大量低成本元件组成，可以调整撞击信号的幅度和相移，从而提供相对较高的波束形成增益。为了最大化通信系统的总速率，我们联合优化基站（BS）的波束形成器和RIS的相移，受到干扰功率阈值、发射功率的单位范数约束和RIS相移的单位模数约束。为了有效地解决这个 NP 难题，我们首先使用分数规划（FP）技术将问题重新表述为更容易处理的形式。然后，我们利用约束的几何特性并采用基于交替流形的优化来分别计算最佳有源波束形成器和 RIS 相移。仿真结果表明，所提出的RIS辅助设计显着降低了通信系统的相互干扰并提高了系统总速率。
Integrated sensing and communication (ISAC) is a key enabler for next-generation wireless communication systems to improve spectral efficiency. However, the coexistence of sensing and communication functionalities can cause harmful interference. In this paper, we propose to use a reconfigurable intelligent surface (RIS) in conjunction with ISAC to address this issue. The RIS is composed of a large number of low-cost elements that can adjust the amplitude and phase shift of impinging signals, thus providing a relatively high beamforming gain. To maximize the sum-rate of the communication system, we jointly optimize the beamformer at the base station (BS) and the phase shifts at the RIS, subject to a threshold on the interference power, the unit-norm constraint of the transmit power, and the unit modulus constraint of the RIS phase shifts. To efficiently tackle this NP-hard problem, we first reformulate the problem into a more tractable form using the fractional programming (FP) technique. Then, we exploit the geometrical properties of the constraints and adopt an alternating manifold-based optimization to compute the optimal active beamformer and the RIS phase shifts, respectively. Simulation results demonstrate that the proposed RIS-assisted design significantly reduces the mutual interference and improves the system sum-rate for the communication system.