Dynamic Reflections: Optimizing Energy Efficiency in Multi-IRS Empowered Green Networks

• Main Authors: Khorasgani, Alireza Qazavi, Tabataba, Foroogh S, Soorki, Mehdi Naderi, Fazel, Mohammad Sadegh
• Format: Journal Article
• Language: English
• Published: 14-02-2023
• DOI: 10.48550/arxiv.2302.06865

Intelligent Reflecting Surface (IRS) technology is revolutionizing wireless
communications by shifting from channel adaptation to a responsive wireless
environment. This paper introduces a multi-IRS assisted millimeter wave
(mm-wave) system, allowing intelligent on/off control of individual IRS
elements. Our objective is to optimize energy efficiency under Quality of
Service (QoS) constraints. We propose an algorithm where the Access Point (AP)
adjusts transmit beamforming, and IRS elements control phaseshifts and on/off
status until convergence. Utilizing a fractional programming (FP) approach for
AP beamforming and Simulated Annealing (SA) for IRS subproblems, we achieve a
suboptimum optimal solution. A modified nested FP approach addresses the
beamforming subproblem. Performance analysis in a practical scenario reveals a
significant up to 132.16\% improvement in energy efficiency compared to
scenarios with randomly selected IRS on/off status. This highlights the
efficacy of our algorithm in enhancing mm-wave communication systems' overall
efficiency.