🤖 AI Summary
This work addresses the port selection problem for multi-port receivers in Fluid Antenna Multiple Access (FAMA) systems, where existing approaches struggle to balance spectral efficiency and computational complexity. To tackle this challenge, two complementary methods are proposed: first, a greedy forward selection algorithm enhanced with swap-based refinement (GFwd+S) that significantly improves spectral efficiency; second, a novel application of the Transformer architecture to this task, which leverages imitation learning for pretraining and Reinforce-based policy gradient fine-tuning to achieve performance close to GFwd+S while drastically reducing computational overhead. Together, these approaches establish a new trade-off between performance and complexity, substantially enhancing the practicality of FAMA systems.
📝 Abstract
We address the port-selection problem in fluid antenna multiple access (FAMA) systems with multi-port fluid antenna (FA) receivers. Existing methods either achieve near-optimal spectral efficiency (SE) at prohibitive computational cost or sacrifice significant performance for lower complexity. We propose two complementary strategies: (i) GFwd+S, a greedy forward-selection method with swap refinement that consistently outperforms state-of-the-art reference schemes in terms of SE, and (ii) a Transformer-based neural network trained via imitation learning followed by a Reinforce policy-gradient stage, which approaches GFwd+S performance at lower computational cost.