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

2025-11-21

AI Summary

This work addresses the spectral efficiency and connectivity limitations of fluid antenna multiple access (FAMA) systems under radio-frequency (RF) chain constraints in mobile devices, focusing specifically on how multi-port activity selection enhances FAMA’s multiplexing capability—particularly for slow-FAMA scenarios. Method: We propose a unified multi-port FAMA modeling framework and design three port-selection algorithms: exhaustive search (optimal benchmark), incremental port selection (IPS), and decremental port selection (DPS). IPS achieves near-optimal performance with low computational complexity by iteratively activating ports to mitigate inter-user interference. Contribution/Results: Theoretical analysis and simulations demonstrate that the proposed multi-port FAMA significantly outperforms conventional single-port FAMA in both spectral efficiency and connection capacity. IPS delivers near-optimal gains at acceptable complexity, offering a practical, RF-resource-efficient paradigm for enhancing multi-access capability in fluid antenna systems.

Technology Category

• Multiagent Systems: Mechanism Design
• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Intelligent Robots: Multi-Robot Systems

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Data management and stream processing for Web, mobile and wireless applications
• User Modeling, Personalization and Recommendation: Federated recommendation systems and personalization
• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs

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.

Problem

• Optimizing multi-port selection for enhanced FAMA multiplexing capability
• Developing low-complexity algorithms for RF-chain-limited massive connectivity
• Analyzing performance and complexity trade-offs in fluid antenna systems

Innovation

• Proposes exhaustive-search port selection for upper bound
• Introduces incremental port selection for near-optimal performance
• Develops decremental port selection with low complexity