Abstract
Reconfigurable intelligent surface (RIS) is widely accepted as a potential technology to assist in communication between base stations (BSs) and users in edge areas. We study the energy efficiency of a RIS-assisted multi-cell communication system with a realistic RIS power consumption model. With the goal of maximizing the energy efficiency of the system, we optimize the transmit beamforming vectors at the BS and the RIS phase shift matrix by a proposed alternative optimization algorithm. First, the transmit beamforming vector is optimized by solving the transformed weighted minimum mean square error (WMMSE) problem. Subsequently, to solve the inconvenience incurred by the discrete relationship between the RIS reflecting unit power consumption and its discrete phase shift, we use a continuous function to approximate their relationship. With this approximation, we can use the majorization minimization (MM) technique to optimize the continuous RIS phase shifts, and then quantize the obtained phase shifts to discrete ones. Simulation results demonstrate that the energy efficiency of the system is effectively optimized by the proposed algorithm.
摘要
可重构智能超表面(RIS)是一种被广泛认可能够辅助基站与边缘用户之间通信的潜在技术. 本文基于实际的RIS功耗模型, 研究了RIS辅助多小区通信系统的能量效率. 为了最大化系统的能量效率, 提出一种交替优化算法, 该算法联合优化了基站处的发射波束成形向量和RIS相移矩阵. 首先, 通过求解转换后的加权最小均方误差问题, 对发射波束成形向量进行优化. 随后, 为解决RIS单元功耗与其离散相移之间的离散关系所导致的计算困难问题, 使用一个连续函数来近似它们的关系. 利用这种近似关系, 采用优化最小化(MM)算法来优化连续的RIS相移, 然后将得到的相移量化为离散相移. 仿真结果表明, 该算法有效提升了系统的能量效率.
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Data availability
The data that support the findings of this study are available from the corresponding author upon reasonable request.
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Danning XU and Xiao LI designed the research. Jinghe WANG provided the data. Danning XU drafted the paper. Xiao LI, Yu HAN, and Shi JIN helped organize the paper. Yu HAN, Xiao LI, and Shi JIN revised and finalized the paper.
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Xiao LI is a corresponding expert of Frontiers of Information Technology & Electronic Engineering, and Shi JIN is an executive lead editor of this special issue; they were not involved with the peer review process of this paper. All the authors declare that they have no conflict of interest.
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Project supported by the National Natural Science Foundation of China (Nos. 62231009 and 61971126), the Natural Science Foundation of Jiangsu Province, China (No. BK20211511), and the Jiangsu Province Frontier Leading Technology Basic Research Project, China (No. BK20212002)
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Xu, D., Han, Y., Li, X. et al. Energy efficiency optimization for a RIS-assisted multi-cell communication system based on a practical RIS power consumption model. Front Inform Technol Electron Eng 24, 1717–1727 (2023). https://doi.org/10.1631/FITEE.2300136
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DOI: https://doi.org/10.1631/FITEE.2300136