Joint Energy Efficiency Optimization for Uplink Multiuser Movable Antenna-Based Wireless Systems Assisted by Movable-Element RIS

TL;DR

This paper proposes a joint optimization framework for energy efficiency in uplink multiuser systems with movable antennas and RIS, using an AO approach to optimize multiple system parameters.

Contribution

It introduces a novel joint optimization method for movable antennas and RIS in uplink systems, enhancing energy efficiency beyond fixed configurations.

Findings

Significant EE gains over fixed-antenna and fixed-RIS benchmarks.

Effective joint optimization of antennas, RIS phase shifts, and transmit powers.

AO framework with Dinkelbach's method and SCA effectively solves the non-convex problem.

Abstract

This paper investigates energy efficiency (EE) optimization for an uplink multiuser system assisted by a movable-element reconfigurable intelligent surface (ME-RIS) and a base station equipped with movable antennas (MA-BS). We jointly optimize the uplink postcoder vectors, user transmit powers, RIS phase shift, and the positions of both the BS antennas and RIS elements to maximize the system EE. The resulting non-convex fractional problem is solved using an alternating optimization (AO) framework, where subproblems are handled via Dinkelbach's method combined with successive convex approximation (SCA). Simulation results show that the proposed scheme achieves significant EE gains over fixed-antenna BS and fixed-element RIS benchmarks.