Multi-Port Selection for FAMA: Massive Connectivity with Fewer RF Chains than Users

TL;DR

This paper introduces and compares port selection algorithms for fluid antenna multiple access (FAMA), demonstrating that low-complexity methods can achieve near-optimal performance in multi-port configurations for massive connectivity.

Contribution

It proposes three port selection algorithms for FAMA, including an optimal exhaustive search and two low-complexity suboptimal methods, enhancing multi-port FAMA performance analysis.

Findings

Proposed algorithms outperform existing multi-port FAMA techniques.

IPS achieves near-optimal performance with manageable complexity.

The study provides a general framework for port selection in FAMA systems.

Abstract

Fluid antenna multiple access (FAMA) is an emerging technology in massive access designed to meet the demands of future wireless communication networks by naturally mitigating multiuser interference through the utilization of the fluid antenna system (FAS) at RF-chain-limited mobile device. The transition from single-active-port to multi-active-port on a shared RF chain for slow FAMA can greatly enhance its multiplexing capability but is not well understood. Motivated by this, this paper proposes and studies three port selection methods: the optimal exhaustive-search port selection (EPS) as a performance upper bound, and two suboptimal, low-complexity algorithms, namely incremental port selection (IPS) and decremental port selection (DPS). Then the performance of multi-active-port slow FAMA is analyzed, and the complexity of the proposed methods is compared. Simulation results indicate that the proposed methods outperform current state-of-the-art multi-port FAMA techniques. In particular, IPS achieves near-optimal performance while maintaining manageable computational complexity. This research provides a more general framework for port selection in FAMA systems.