FAS-RIS Communication: Model, Analysis, and Optimization

TL;DR

This paper explores a novel FAS-RIS communication system, deriving outage probability bounds and optimizing RIS phase shifts to improve reliability, with simulations confirming the effectiveness of the proposed methods.

Contribution

It introduces a new FAS-RIS system model, derives outage probability bounds, and proposes an optimized phase shift scheme to enhance system performance.

Findings

Proposed outage probability bounds closely match simulations.

Optimized phase shifts significantly reduce system outage.

The FAS-RIS scheme outperforms existing benchmarks.

Abstract

This correspondence investigates the novel fluid antenna system (FAS) technology, combining with reconfigurable intelligent surface (RIS) for wireless communications, where a base station (BS) communicates with a FAS-enabled user with the assistance of a RIS. To analyze this technology, we derive the outage probability based on the block-diagonal matrix approximation (BDMA) model. With this, we obtain the upper bound, lower bound, and asymptotic approximation of the outage probability to gain more insights. Moreover, we design the phase shift matrix of the RIS in order to minimize the system outage probability. Simulation results confirm the accuracy of our approximations and that the proposed schemes outperform benchmarks significantly.