Fluid Antennas Assisted RIS-NOMA Communication Networks

TL;DR

This paper proposes integrating fluid antennas into RIS-assisted NOMA networks, formulating a sum rate maximization problem and developing an iterative optimization algorithm, demonstrating significant throughput improvements in simulations.

Contribution

Introducing a novel FAS-RIS-NOMA framework with an optimized joint design, enhancing system throughput over traditional methods.

Findings

FAS-RIS-NOMA outperforms traditional antenna systems and OMA at high SNR.

Increasing RIS elements and FAS size boosts sum rate.

The proposed iterative algorithm effectively optimizes fluid ports, RIS deployment, and phase shifts.

Abstract

This paper introduces a fluid antenna system (FAS) into reconfigurable intelligent surface (RIS) assisted non-orthogonal multiple access (NOMA) communication networks, where the non-orthogonal users are equipped with planar fluid antennas. Specifically, we formulate a sum rate maximization problem for FAS-RIS-NOMA networks, which jointly optimizes the fluid ports, the RIS deployment, and the phase shift matrix. To solve the resulting non-convex optimization problem involving highly coupled variables, an iterative algorithm based on alternating optimization is employed to decompose the original problem into three subproblems. Exhaustive search is employed for optimizing the fluid ports, particle swarm optimization is used for the RIS deployment, and semidefinite relaxation with successive convex approximation is adopted for optimizing the phase shift matrix. Finally, the simulation results show that: 1) compared with traditional antenna systems and orthogonal multiple access, the FAS-RIS-NOMA networks achieve higher system throughput under high signal-to-noise ratio conditions; and 2) by increasing the number of RIS elements and enlarging the FAS size, the sum rate of FAS-RIS-NOMA networks can be significantly enhanced.