Problem
Research questions and friction points this paper is trying to address.
Slow Fluid Antenna Multiple Access
HARQ-CC
Quality of Service
Joint Optimization
User Concurrency
QoS-Aware Joint Concurrency and HARQ-Limit Design for HARQ-CC-Aided Slow Fluid Antenna Multiple Access
🤖 AI Summary
This study addresses the challenge that the number of concurrent users and HARQ retransmissions in slow fluid antenna multiple access (FAS) systems are constrained by quality-of-service (QoS) requirements, necessitating joint optimization. To this end, a QoS-aware two-stage joint design framework is proposed. First, the decoding failure probability is analytically derived to establish signal-to-interference ratio distribution analysis and a multi-round decoding model. Subsequently, it is proven that identifying the first feasible concurrency level minimizes service duration, enabling an optimal binary search algorithm. This work significantly expands the QoS-feasible region of FAS. Simulation results demonstrate that the proposed scheme supports six concurrent users and outperforms conventional fixed-configuration approaches, validating the effectiveness of jointly adapting user concurrency and retransmission limits.
📝 Abstract
Hybrid automatic repeat request with Chase combining (HARQ-CC) improves the reliability of slow fluid antenna multiple access (sFAMA), but its transmission limit must be jointly optimized with user concurrency. This paper proposes a quality-of-service (QoS)-aware joint design of concurrency level U and HARQ limit C for downlink HARQ-CC-aided sFAMA. Based on the selected-port signal-to-interference ratio (SIR) distribution, we derive multi-round decoding failure probabilities and develop a two-stage optimization that maximizes feasible concurrency and then selects the minimum C satisfying outage and mean-service constraints. We prove that the first feasible C minimizes service duration for a given U, and that feasible U values form an initial segment, enabling optimal bisection search. Numerical results agree with Monte Carlo simulations under full Jakes spatial covariance. The proposed adaptive FAS design supports six concurrent users, compared with three to five for fixed-HARQ FAS and two for HARQ-adaptive fixed-position-antenna (FPA), demonstrating that joint concurrency and HARQ adaptation expands the QoS-feasible region of FAS.
Innovation
Methods, ideas, or system contributions that make the work stand out.
Fluid Antenna Systems
HARQ with Chase Combining
Joint Concurrency Optimization
QoS-Aware Design
Slow FAMA
🔎 Similar Papers
No similar papers found.
