Fluid Antenna-Empowered Receive Spatial Modulation

2025-06-09

AI Summary

This paper addresses three key challenges in integrating fluid antennas (FAs) with receive spatial modulation (RSM): difficult port selection, lack of theoretical performance analysis, and high detection complexity. To this end, we propose a novel FA-RSM system that deeply integrates the dynamically reconfigurable multi-port capability of FAs with RSM’s spatial-domain information encoding mechanism. We design a capacity-optimal port selection algorithm and two low-complexity alternatives, and establish the first theoretical framework for analyzing port selection performance. Furthermore, we propose two near-optimal detectors with significantly reduced computational complexity. Simulation results demonstrate that FA-RSM substantially outperforms conventional RSM; increasing the number of FA ports yields performance gains that eventually saturate; and the proposed algorithms achieve substantial implementation cost reduction with negligible performance loss.

Technology Category

• Intelligent Robots: Multimodal Perception & Sensor Fusion
• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Multiagent Systems: Agent Communication

Application Category

• Search and Retrieval-Augmented AI: Retrieval-Augmented Generation (RAG) and multi-modal RAG
• Security and Privacy: Large-scale security measurements
• Systems and Infrastructure for Web, Mobile and WoT: Data management and stream processing for Web, mobile and wireless applications

Abstract

Fluid antenna (FA), as an emerging antenna technology, fully exploits spatial diversity. This paper integrates FA with the receive spatial modulation (RSM) scheme and proposes a novel FA-empowered RSM (FA-RSM) system. In this system, the transmitter is equipped with an FA that simultaneously activates multiple ports to transmit precoded signals. We address three key challenges in the FA-RSM system: port selection, theoretical analysis, and detection. First, for port selection, an optimal algorithm from a capacity maximization perspective are proposed, followed by two low-complexity alternatives. Second, for theoretical analysis, performance evaluation metrics are provided for port selection, which demonstrate that increasing the number of activated ports enhances system performance. Third, regarding detection, two low-complexity detectors are proposed. Simulation results confirm that the FA-RSM system significantly outperforms the conventional RSM system. The proposed low-complexity port selection algorithms facilitate minimal performance degradation. Moreover, while activating additional ports improves performance, the gain gradually saturates due to inherent spatial correlation, highlighting the importance of effective port selection in reducing system complexity and cost. Finally, both proposed detectors achieve near-optimal detection performance with low computational complexity, emphasizing the receiver-friendly nature of the FA-RSM system.

Problem

• Integrates fluid antenna with receive spatial modulation for enhanced performance
• Addresses port selection, theoretical analysis, and detection challenges in FA-RSM
• Proposes low-complexity algorithms for port selection and near-optimal detection

Innovation

• FA-RSM system integrates fluid antenna with receive spatial modulation
• Optimal and low-complexity port selection algorithms proposed
• Low-complexity detectors achieve near-optimal performance