Guo, Wei;
Liang, Kai;
Zheng, Gan;
Chu, Xiaoli;
Zhou, Guorong;
Wong, Kai-Kit;
Chae, Chan-Byoung;
(2025)
LLM-Based Port Selection and Beamforming for Multiuser MISO With Fluid Antenna Systems.
IEEE Transactions on Network Science and Engineering
pp. 1-17.
10.1109/TNSE.2025.3626002.
(In press).
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Abstract
Fluid antenna systems (FAS) introduce additional spatial degrees of freedom (DoF) by dynamically adjusting antenna positions. When integrated with multiple-input multiple-output (MIMO) technologies (forming MIMO-FAS), this capability significantly enhances wireless communication performance. However, the joint optimization of high-dimensional port selection and beamforming in MIMO-FAS presents a challenging nonconvex combinatorial problem. In this paper, we propose a novel large language model (LLM)-based intelligent framework for jointly optimizing port selection and beamforming in multiuser MIMO-FAS systems. The objective is to maximize the sum rate under base station (BS) power and port activation constraints. Departing from the conventional two-stage approaches, where port selection and beamforming are handled sequentially, we adopt a parallel output strategy that simultaneously determines port indices and beamforming coefficients, leveraging the multi-task learning capabilities of LLMs. To enhance efficiency, we incorporate low-rank adaptation (LoRA) for fine-tuning pre-trained LLMs, significantly reducing training cost while maintaining generalization performance. Also, we employ Gumbel-Sinkhorn stochastic relaxation to make discrete port selection differentiable, enabling end-to-end optimization. Numerical results demonstrate that the proposed method outperforms state-of-the-art techniques in terms of sum rate, validating the effectiveness of the LLM-driven joint optimization approach.
| Type: | Article |
|---|---|
| Title: | LLM-Based Port Selection and Beamforming for Multiuser MISO With Fluid Antenna Systems |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1109/TNSE.2025.3626002 |
| Publisher version: | https://doi.org/10.1109/tnse.2025.3626002 |
| Language: | English |
| Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | Fluid antenna system, large language model (LLM), multiuser MISO, port selection, LoRA fine-tuning |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Electronic and Electrical Eng |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10217540 |
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