Improvement of Bi-Directional Communications using Solar Powered Reconfigurable Intelligent Surfaces


Recently, there has been a flurry of research on the use of Reconfigurable Intelligent Surfaces (RIS) in wireless networks to create dynamic radio environments. In this paper, we investigate the use of an RIS panel to improve bi-directional communications. Assuming that the RIS will be located on the facade of a building, we propose to connect it to a solar panel that harvests energy to be used to power the RIS panel's smart controller and reflecting elements. Therefore, we present a novel framework to optimally decide the transmit power of each user and the number of elements that will be used to reflect the signal of any two communicating pair in the system (user-user or base station-user). An optimization problem is formulated to jointly minimize a scalarized function of the energy of the communicating pair and the RIS panel and to find the optimal number of reflecting elements used by each user. Although the formulated problem is a mixed-integer nonlinear problem, the optimal solution is found by linearizing the non-linear constraints. Besides, a more efficient close to the optimal solution is found using Bender decomposition. Simulation results show that the proposed model is capable of delivering the minimum rate of each user even if line-of-sight communication is not achievable.

Meeting Name

2021 International Conference on Computer Communications and Networks, ICCCN (2021: Jul. 19-22, Athens, Greece)


Electrical and Computer Engineering


This research was supported in part by grant 1827211 from the National Science Foundation, USA.

Keywords and Phrases

Bender Decomposition; Optimization; Reconfigurable Intelligent Surfaces; Two-Way Communications

International Standard Book Number (ISBN)


International Standard Serial Number (ISSN)


Document Type

Article - Conference proceedings

Document Version


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Publication Date

22 Jul 2021