Optimizing Fluid Antenna Configurations for Constructive Interference Precoding

Fuente: arXiv
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Main Authors: Sun, Wenxuan, Shao, Mingjie, Zhu, Luteng, Ge, Yao, Zhang, Tong, Liu, Zhi
Format: Preprint
Published: 2025
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author Sun, Wenxuan
Shao, Mingjie
Zhu, Luteng
Ge, Yao
Zhang, Tong
Liu, Zhi
author_facet Sun, Wenxuan
Shao, Mingjie
Zhu, Luteng
Ge, Yao
Zhang, Tong
Liu, Zhi
contents The fluid antenna system (FAS) has emerged as a new physical-layer concept to provide enhanced propagation conditions for multiuser multiple-input multiple-output (MIMO) communications over conventional fixed arrays. This work focuses on minimizing the maximum symbol error probability (SEP) under $M$-ary phase shift keying (MPSK) signaling in a multiuser downlink equipped with FAS, where each antenna moves within nonoverlapping intervals. This specific problem of joint SEP minimization with FAS and constructive interference (CI) precoding has not been previously addressed. The resulting problem turns out to be a nonconvex and nonsmooth optimization challenge. We transform the SEP minimization problem into a safety margin maximization problem in constructive interference precoding. Then, we customize a smoothing technique and a block coordinate descent (BCD) algorithm, with emphasis on low computational complexity. Simulation results show that our approach can reduce bit error rate (BER) compared to both the fixed arrays and FAS designed by existing particle swarm optimization (PSO). Also, our approach shows attractively low computational complexity compared to PSO benchmarks.
format Preprint
id arxiv_https___arxiv_org_abs_2507_11093
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Optimizing Fluid Antenna Configurations for Constructive Interference Precoding
Sun, Wenxuan
Shao, Mingjie
Zhu, Luteng
Ge, Yao
Zhang, Tong
Liu, Zhi
Signal Processing
Information Theory
The fluid antenna system (FAS) has emerged as a new physical-layer concept to provide enhanced propagation conditions for multiuser multiple-input multiple-output (MIMO) communications over conventional fixed arrays. This work focuses on minimizing the maximum symbol error probability (SEP) under $M$-ary phase shift keying (MPSK) signaling in a multiuser downlink equipped with FAS, where each antenna moves within nonoverlapping intervals. This specific problem of joint SEP minimization with FAS and constructive interference (CI) precoding has not been previously addressed. The resulting problem turns out to be a nonconvex and nonsmooth optimization challenge. We transform the SEP minimization problem into a safety margin maximization problem in constructive interference precoding. Then, we customize a smoothing technique and a block coordinate descent (BCD) algorithm, with emphasis on low computational complexity. Simulation results show that our approach can reduce bit error rate (BER) compared to both the fixed arrays and FAS designed by existing particle swarm optimization (PSO). Also, our approach shows attractively low computational complexity compared to PSO benchmarks.
title Optimizing Fluid Antenna Configurations for Constructive Interference Precoding
topic Signal Processing
Information Theory
url https://arxiv.org/abs/2507.11093