ABSTRACT Reconfigurable Intelligent Surface (RIS) is emerging as a potential solution for Tera Hertz communication. It supports a re‐configurable and smart wireless environment by enhancing the signal strength and reflecting it to the desired receiver which aids in improving energy efficiency. This article presents a novel mathematical framework of a mixed integer nonlinear programming (MINLP) problem to maximize the energy efficiency (EE) of a RIS‐based multi‐user network having a multi‐antenna base station (BS). The formulated problem is a concave fractional programming problem (CFP) which is transformed into a concave program using the proposed Charnes–Cooper transformation (CCT). MINLP problems are generally NP‐hard in nature and their complexity increases with the number of users, therefore, an outer approximation algorithm (OAA) is applied which gives.
Abid et al. (2026) studied this question.