论文标题

具有分布式重新配置的智能表面的节能无线通信

Energy-Efficient Wireless Communications with Distributed Reconfigurable Intelligent Surfaces

论文作者

Yang, Zhaohui, Chen, Mingzhe, Saad, Walid, Xu, Wei, Shikh-Bahaei, Mohammad, Poor, H. Vincent, Cui, Shuguang

论文摘要

本文研究了具有可分布的可重构智能表面(RISS)的无线通信网络的资源分配问题。在该网络中,多个RIS在空间上分布以服务于无线用户,并且通过动态控制每个RIS的开关状态并优化RISS的反射系数矩阵,通过动态控制每个RIS的开关状态来最大化网络的能效。该问题被认为是传输光束成型和RIS控制的关节优化问题,其目标是在用户的最低利率约束下最大化能源效率。为了解决此问题,为单用户案例和多用户案例提出了两种迭代算法。对于单用户案例,使用连续的凸近似方法解决了相优化问题,该方法在每个步骤中都接受封闭形式的解决方案。此外,使用双重方法获得了最佳的RIS开关状态。对于多用户案例,提出了一种低复杂性贪婪的搜索方法来解决RIS On-Ow-On-Off优化问题。仿真结果表明,与常规RIS方案和放大和前向继电器方案相比,该方案在单用户和多用户案例的能源效率方面最多可获得33 \%和68 \%的收益。

This paper investigates the problem of resource allocation for a wireless communication network with distributed reconfigurable intelligent surfaces (RISs). In this network, multiple RISs are spatially distributed to serve wireless users and the energy efficiency of the network is maximized by dynamically controlling the on-off status of each RIS as well as optimizing the reflection coefficients matrix of the RISs. This problem is posed as a joint optimization problem of transmit beamforming and RIS control, whose goal is to maximize the energy efficiency under minimum rate constraints of the users. To solve this problem, two iterative algorithms are proposed for the single-user case and multi-user case. For the single-user case, the phase optimization problem is solved by using a successive convex approximation method, which admits a closed-form solution at each step. Moreover, the optimal RIS on-off status is obtained by using the dual method. For the multi-user case, a low-complexity greedy searching method is proposed to solve the RIS on-off optimization problem. Simulation results show that the proposed scheme achieves up to 33\% and 68\% gains in terms of the energy efficiency in both single-user and multi-user cases compared to the conventional RIS scheme and amplify-and-forward relay scheme, respectively.

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