papers

Publications (39)

cs.IT2020

Fluid Antenna Systems

Kai-Kit Wong, Arman Shojaeifard, Kin-Fai Tong +1

Over the past decades, multiple antenna technologies have appeared in many different forms, most notably as multiple-input multiple-output (MIMO), to transform wireless communicati…

eess.SP2026

DOA Estimation for Low-Altitude Networks: HAD Architectures, Methods, and Challenges

Ye Tian, Tuo Wu, Jintao Wu +4

With the rapid expansion of low-altitude economy (LAE) services and the growing demand for integrated sensing and communication (ISAC) in air-ground networks, reliable direction-of…

eess.SP2025

Toward Practical Fluid Antenna Systems: Co-Optimizing Hardware and Software for Port Selection and Beamforming

Sai Xu, Kai-Kit Wong, Yanan Du +4

This paper proposes a hardware-software co-design approach to efficiently optimize beamforming and port selection in fluid antenna systems (FASs). To begin with, a fluid-antenna (F…

eess.SP2024

A Pixel-based Reconfigurable Antenna Design for Fluid Antenna Systems

Jichen Zhang, Junhui Rao, Zhaoyang Ming +5

Fluid Antenna Systems (FASs) have recently been proposed for enhancing the performance of wireless communication. Previous antenna designs to meet the requirements of FAS have been…

eess.SP2025

Reimagining Wireless Connectivity: The FAS-RIS Synergy for 6G Smart Cities

Tuo Wu, Kai-Kit Wong, Jie Tang +6

Fluid antenna system (FAS) represents the concept of treating antenna as a reconfigurable physical-layer resource to broaden system design and network optimization and inspire next…

cs.IT2025

Fluid Antenna System-Assisted Self-Interference Cancellation for In-Band Full Duplex Communications

Hanjiang Hong, Kai-Kit Wong, Hao Xu +5

In-band full-duplex (IBFD) systems are expected to double the spectral efficiency compared to half-duplex systems, provided that loopback self-interference (SI) can be effectively…

eess.SP2026

Scalable Fluid Antenna Systems: A New Paradigm for Array Signal Processing

Tuo Wu, Ye Tian, Jie Tang +8

Most existing antenna array-based source localization methods rely on fixed-position arrays (FPAs) and strict assumptions about source field conditions (near-field or far-field), w…

cs.IT2020

Performance Limits of Fluid Antenna Systems

Kai-Kit Wong, Arman Shojaeifard, Kin-Fai Tong +1

Fluid antenna represents a concept where a mechanically flexible antenna can switch its location freely within a given space. Recently, it has been reported that even with a tiny s…

eess.SP2026

Physical Layer Security for FAS-Aided Short-Packet Systems: A Variable Block-Correlation Approach

Jianchao Zheng, Tuo Wu, Kai-Kit Wong +5

This paper presents a comprehensive physical layer security (PLS) framework for fluid antenna system (FAS)-aided short-packet communications under the variable block-correlation mo…

eess.SP2026

Fundamental Analysis of Scalable Fluid Antenna Systems: Identifiability Limits, Information Theory, and Joint Processing

Tuo Wu, Kai-Kit Wong, Jie Tang +8

Unlike fixed-position arrays with static observation entropy, the scalable fluid antenna system (S-FAS) can dynamically adjust its aperture to form different observation spaces wit…

eess.SP2025

Fluid Antennas: Reshaping Intrinsic Properties for Flexible Radiation Characteristics in Intelligent Wireless Networks

Wen-Jun Lu, Chun-Xing He, Yongxu Zhu +4

Fluid antennas present a relatively new idea for harnessing the fading and interference issues in multiple user wireless systems, such as 6G. Here, we systematically compare their…

cs.IT2024

Cache-Enabled Millimetre-Wave Fluid Antenna Systems: Modeling and Performance

Farshad Rostami Ghadi, Kai-Kit Wong, Kin-Fai Tong +1

This letter investigates the performance of content caching in a heterogeneous cellular network (HetNet) consisting of fluid antenna system (FAS)-equipped mobile users (MUs) and mi…

cs.IT2026

Enormous Fluid Antenna Systems (E-FAS) under Correlated Surface-Wave Leakage: Physical Layer Security

Farshad Rostami Ghadi, Kai-Kit Wong, Masoud Kaveh +3

Enormous fluid antenna systems (E-FAS) have recently emerged as a surface-wave (SW)-enabled architecture that can induce controllable large-scale channel gains through guided elect…

eess.SP2025

Fluid Antenna System Empowering 5G NR

Hanjiang Hong, Kai-Kit Wong, Haoyang Li +5

Fluid antenna system (FAS) is an emerging technology that uses the new form of shape- and position-reconfigurable antennas to empower the physical layer for wireless communications…

cs.IT2023

Fluid Antenna-Assisted Dirty Multiple Access Channels over Composite Fading

Farshad Rostami Ghadi, Kai-Kit Wong, F. Javier Lopez-Martinez +3

This letter investigates the application of the emerging fluid antenna (FA) technology in multiuser communication systems when side information (SI) is available at the transmitter…

cs.IT2013

Performance of Joint Channel and Physical Network Coding Based on Alamouti STBC

Yi Fang, Lin Wang, Kai-Kit Wong +1

This work considers the protograph-coded physical network coding (PNC) based on Alamouti space-time block coding (STBC) over Nakagami-fading two-way relay channels, in which both t…

eess.SP2025

Intelligent Sky Mirrors: SAC-Driven MF-RIS Optimization for Secure NOMA in Low-Altitude Economy

Sai Zhao, Fanjin Kong, Dong Tang +5

Low-altitude economy (LAE) has become a key driving force for smart cities and economic growth. To address spectral efficiency and communication security challenges in LAE, this pa…

eess.SP2025

Variable Block-Correlation Modeling and Optimization for Secrecy Analysis in Fluid Antenna Systems

Tuo Wu, Kwai-Man Luk, Jie Tang +9

Fluid antenna systems (FAS) are emerging as a transformative enabler for sixth-generation (6G) wireless communications, providing unprecedented spatial diversity through dynamic re…

cs.IT2020

Fluid Antenna Multiple Access

Kai-Kit Wong, Kin-Fai Tong

Fluid antenna is a novel technology that can make an antenna appear instantly at one of N preset locations in a predefined space. An important application is to adopt fluid antenna…

physics.app-ph2025

Be Water, My Antennas: Riding on Radio Wave Fluctuation in Nature for Spatial Multiplexing using Programmable Meta-Fluid Antenna

Baiyang Liu, Kin-Fai Tong, Kai-Kit Wong +2

Interference and scattering, often deemed undesirable, are inevitable in wireless communications, especially when the current mobile networks and upcoming sixth generation (6G) hav…

eess.SP2025

The Future is Fluid: Revolutionizing DOA Estimation with Sparse Fluid Antennas

He Xu, Tuo Wu, Ye Tian +8

This paper investigates a design framework for sparse fluid antenna systems (FAS) enabling high-performance direction-of-arrival (DOA) estimation, particularly in challenging milli…

cs.IT2023

An Information-Theoretic Characterization of MIMO-FAS: Optimization, Diversity-Multiplexing Tradeoff and -Outage Capacity

Wee Kiat New, Kai-Kit Wong, Hao Xu +2

Multiple-input multiple-output (MIMO) system has been the defining mobile communications technology in recent generations. With the ever-increasing demands looming towards the sixt…

eess.SP2025

Meta Fluid Antenna: Architecture Design, Performance Analysis, Experimental Examination

Baiyang Liu, Jiewei Huang, Tuo Wu +7

Fluid antenna systems (FAS) have recently emerged as a promising solution for sixth-generation (6G) ultra-dense connectivity. These systems utilize dynamic radiating and/or shaping…

cs.IT2025

A Contemporary Survey on Fluid Antenna Systems: Fundamentals and Networking Perspectives

Hanjiang Hong, Kai-Kit Wong, Hao Xu +8

The explosive growth of teletraffic, fueled by the convergence of cyber-physical systems and data-intensive applications, such as the Internet of Things (IoT), autonomous systems,…

cs.IT2023

Copula-based Performance Analysis for Fluid Antenna Systems under Arbitrary Fading Channels

Farshad Rostami Ghadi, Kai-Kit Wong, F. Javier Lopez-Martinez +1

In this letter, we study the performance of a single-user fluid antenna system (FAS) under arbitrary fading distributions, in which the fading channel coefficients over the ports a…

cs.IT2013

Performance Analysis of Protograph LDPC Codes for Nakagami- Fading Relay Channels

Yi Fang, Kai-Kit Wong, Lin Wang +1

In this paper, we investigate the error performance of the protograph (LDPC) codes over Nakagami- fading relay channels. We first calculate the decoding thresholds of the protog…

cs.IT2023

Fluid Antenna System: New Insights on Outage Probability and Diversity Gain

Wee Kiat New, Kai-Kit Wong, Hao Xu +2

To enable innovative applications and services, both industry and academia are exploring new technologies for sixth generation (6G) communications. One of the promising candidates…

eess.SP2024

A Tutorial on Fluid Antenna System for 6G Networks: Encompassing Communication Theory, Optimization Methods and Hardware Designs

Wee Kiat New, Kai-Kit Wong, Hao Xu +9

The advent of the sixth-generation (6G) networks presents another round of revolution for the mobile communication landscape, promising an immersive experience, robust reliability,…

eess.SP2026

Taming the Bessel Landscape: Joint Antenna Position Optimization for Spatial Decorrelation in Fluid MIMO Systems

Tuo Wu, Kai-Kit Wong, Baiyang Liu +2

When the concept of fluid antenna system (FAS) is applied to multiple-input multiple-output (MIMO) systems, this gives rise to MIMO-FAS, a.k.a.~fluid MIMO. Under rich scattering, t…

eess.SP2024

Design and Implementation of mmWave Surface Wave Enabled Fluid Antennas and Experimental Results for Fluid Antenna Multiple Access

Yuanjun Shen, Boyi Tang, Shuai Gao +4

While multiple-input multiple-output (MIMO) technologies continue to advance, concerns arise as to how MIMO can remain scalable if more users are to be accommodated with an increas…

eess.SP2025

FAS-ARIS: Turning Multipath Challenges Into Localization Opportunities

Hua Chen, Tao Gong, Tuo Wu +5

Traditional single-input single-output (SISO) systems face fundamental limitations in achieving accurate three-dimensional (3D) localization due to limited spatial degrees of freed…

eess.SP2025

An Fluid Antenna Array-Enabled DOA Estimation Method: End-Fire Effect Suppression

Jiaji Ren, Ye Tian, Baiyang Liu +5

Direction of Arrival (DOA) estimation serves as a critical sensing technology poised to play a vital role in future intelligent and ubiquitous communication systems. Despite the de…

eess.SP2025

Fluid Antenna Enabled Direction-of-Arrival Estimation Under Time-Constrained Mobility

He Xu, Tuo Wu, Ye Tian +8

Fluid antenna (FA) technology has emerged as a promising approach in wireless communications due to its capability of providing increased degrees of freedom (DoFs) and exceptional…

cs.IT2024

A Gaussian Copula Approach to the Performance Analysis of Fluid Antenna Systems

Farshad Rostami Ghadi, Kai-Kit Wong, F. Javier Lopez-Martinez +3

This paper investigates the performance of a single-user fluid antenna system (FAS), by exploiting a class of elliptical copulas to describe the dependence structure amongst the fl…

cs.IT2026

Enormous Fluid Antenna Systems (E-FAS)--Part II: Channel Estimation

Farshad Rostami Ghadi, Kai-Kit Wong, Masoud Kaveh +4

Enormous fluid antenna systems (E-FAS) have recently emerged as a new wireless architecture in which intelligent metasurfaces act as guided electromagnetic interfaces, enabling sur…

eess.SP2020

A Vision to Smart Radio Environment: Surface Wave Communication Superhighways

Kai-Kit Wong, Kin-Fai Tong, Zhiyuan Chu +1

Complementary to traditional approaches that focus on transceiver design for bringing the best out of unstable, lossy fading channels, one radical development in wireless communica…

eess.SP2026

How Many Independent Modes Does a Fluid Antenna Have? A Closed-Form Outage Analysis via Equivalent Degrees of Freedom

Tuo Wu, Junteng Yao, Kai-Kit Wong +5

In a fluid antenna system (FAS), a single reconfigurable antenna is able to activate one of correlated ports to exploit spatial diversity. However, outage analysis is challengi…

math.OC2022

Port Selection for Fluid Antenna Systems

Zhi Chai, Kai-Kit Wong, Kin-Fai Tong +2

Fluid antenna system promises to obtain enormous diversity in the small space of a mobile device by switching the position of the radiating element to the most desirable position f…

cs.IT2026

Enormous Fluid Antenna Systems (E-FAS) for Wireless Sensing: Channel Modeling and Conditional Estimation Limits

Farshad Rostami Ghadi, Kai-Kit Wong, Jose D. Vega-Sanchez +2

In this paper, we develop a fundamental analytical framework for integrated sensing and communications (ISAC) enabled by the Enormous Fluid Antenna System (E-FAS), which transforms…