Fluid Antenna Systems

By Kai‐Kit Wong, Arman Shojaeifard, Kin-Fai Tong, Yangyang Zhang. IEEE Transactions on Wireless Communications, 2020

901 citations recorded by the source corpus.

Over the past decades, multiple antenna technologies have appeared in many different forms, most notably as multiple-input multiple-output (MIMO), that have transformed wireless communications for extraordinary diversity and multiplexing gains. The various MIMO technologies have been based on placing a number of antennas at some fixed locations which dictate the fundamental limit on the achievable performance. By contrast, this paper envisages the scenario in which the physical position of an antenna can be switched freely to one of the <inline-formula> <tex-math notation="LaTeX">$N$ </tex-math></inline-formula> positions over a fixed-length line space to pick up the strongest signal in the manner of traditional selection diversity. We refer to this system as a <italic>fluid antenna system</italic> (FAS) for tremendous flexibility in its possible shape and position. The aim of this paper is to study the achievable performance of a single-antenna FAS system with a fixed length and <inline-formula> <tex-math notation="LaTeX">$N$ </tex-math></inline-formula> in arbitrarily correlated Rayleigh fading channels. Our contributions include exact and approximate closed-form expressions for the outage probability of FAS. We also derive an upper bound for the outage probability, from which it is discovered that a single-antenna FAS given any arbitrarily small space can outperform an <inline-formula> <tex-math notation="LaTeX">$L$ </tex-math></inline-formula>-antenna maximum ratio combining (MRC) system if <inline-formula> <tex-math notation="LaTeX">$N$ </tex-math></inline-formula> is large enough. Our analysis also reveals the minimum required size of the FAS, and how large <inline-formula> <tex-math notation="LaTeX">$N$ </tex-math></inline-formula> is considered enough for the FAS to surpass MRC.

Subfields: Aerospace Engineering, Computer Networks and Communications, Electrical and Electronic Engineering

View Paper: https://www.semanticscholar.org/paper/be5ac53abcbaaace45f2abdf37dc077cbbf986e6

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Aerospace Engineering

1. Rui Zhang
2. Lipeng Zhu
3. Wenyan Ma
4. Robert Schober
5. Zhiguo Ding
6. H. Vincent Poor
7. Boyu Ning
8. Kai‐Kit Wong

In Computer Networks and Communications

1. Robert Schober
2. H. Vincent Poor
3. Zhiguo Ding
4. Lipeng Zhu
5. Rui Zhang
6. Wenyan Ma
7. Kai‐Kit Wong
8. Yong Zeng

In Electrical and Electronic Engineering

1. Rui Zhang
2. Robert Schober
3. Zhiguo Ding
4. H. Vincent Poor
5. Lipeng Zhu
6. Wenyan Ma
7. Yuanwei Liu
8. Kai‐Kit Wong

Citations in the corpus

• Fluid Antenna Multiple Access (2020, background): “It is worth emphasizing that the above-mentioned analysis was not required in [36], [37] in which the aim was to understand the diversity gain and how much it could be translated into the signal-to-noise ratio (SNR) based outage probability performance and ergodic capacity.”
• Movable-Antenna Enhanced Multiuser Communication via Antenna Position Optimization (2023, methodology): “On the other hand, in [21]– [24], the port-based channel model in a 1D line space under the uniform scattering assumption may not be applicable to practical systems with finite number of scatters and multi-paths in the 3D space.”
• Modeling and Performance Analysis for Movable Antenna Enabled Wireless Communications (2022, background): “However, the discrete port-based channel model employed in [30] and [31] cannot completely characterize and fully exploit the wireless channel spatial variation in continuous regions.”
• MIMO Capacity Characterization for Movable Antenna Systems (2022, background): “By using conductive fluids as materials for antennas, the position of a receive antenna can be switched freely among all candidate ports over a fixed-length line, and thus the signal with the highest signal-to-noise ratio (SNR) can be received [15].”
• A Tutorial on Fluid Antenna System for 6G Networks: Encompassing Communication Theory, Optimization Methods and Hardware Designs (2024, methodology): “To obtain the best performance, the port with the maximum amplitude should be activated [52], i.e., By choosing the optimal port, the rate of Tx-SISO-FAS can be computed as where SNR is the signal-to-noise ratio (SNR) and the outage probability of Tx-SISO-FAS can be expressed as where R min is the…”
• Flexible-Antenna Systems: A Pinching-Antenna Perspective (2024, positive): “As the latest members of the flexible-antenna system family, both fluid antennas and movable antennas are based on the idea to change the locations of the antennas at the transceivers, such that more favorable channel conditions are experienced by the transceivers [12], [13], [14], [15].”