Fluid Antenna Multiple Access with Simultaneous Non-unique Decoding in Strong Interference Channel

TL;DR

This paper explores fluid antenna multiple access combined with simultaneous non-unique decoding to improve data rates in strong interference channels, showing significant benefits over traditional systems.

Contribution

It introduces a novel combination of FAMA and SND for strong interference channels and analyzes their performance metrics.

Findings

FAMA with SND outperforms traditional fixed-position systems.

Derived key statistics for SNR and INR in two-user IC.

Numerical results demonstrate substantial capacity gains.

Abstract

Fluid antenna system (FAS) is gaining attention as an innovative technology for boosting diversity and multiplexing gains. As a key innovation, it presents the possibility to overcome interference by position reconfigurability on one radio frequency (RF) chain, giving rise to the concept of fluid antenna multiple access (FAMA). While FAMA is originally designed to deal with interference mainly by position change and treat interference as noise, this is not rate optimal, especially when suffering from a strong interference channel (IC) where all positions have strong interference. To tackle this, this paper considers a two-user strong IC where FAMA is used in conjunction with simultaneous nonunique decoding (SND). Specifically, we analyze the key statistics for the signal-to-noise ratio (SNR) and interference-to-noise ratio (INR) for a canonical two-user IC setup, and subsequently derive the delay outage rate (DOR), outage probability (OP) and ergodic capacity (EC) of the FAMA-IC. Our numerical results illustrate huge benefits of FAMA with SND over traditional fixed-position antenna systems (TAS) with SND in the fading IC.