Optimal, Low-Complexity Beamforming for Discrete Phase Reconfigurable Intelligent Surfaces
Sanchez, Juan LU ; Bengtsson, Erik L LU ; Rusek, Fredrik LU ; Flordelis i Minguez, José LU ; Zhao, Kun and Tufvesson, Fredrik LU
(2021)
IEEE Global Communications Conference, GLOBECOM 2021
- Abstract
- Reflective reconfigurable intelligent surface (RIS) technology is regarded as an innovative, cost- and power-effective solution that aims at influencing the wireless channel through controlled scattering. The technology can be realized by using metamaterials and/or resonant elements that scatter electromagnetic waves with a configurable phase shift. Most of the previous work on beamforming techniques for RIS assumes ideal hardware and, thus, continuous phase shifts. However, hardware constraints limit the phase shift resolution, manifested into the amount of discrete phase shifts that can be configured into each RIS element. This paper aims to offer a discrete phase shift beamforming algorithm for reflective RISs that targets minimization... (More)
- Reflective reconfigurable intelligent surface (RIS) technology is regarded as an innovative, cost- and power-effective solution that aims at influencing the wireless channel through controlled scattering. The technology can be realized by using metamaterials and/or resonant elements that scatter electromagnetic waves with a configurable phase shift. Most of the previous work on beamforming techniques for RIS assumes ideal hardware and, thus, continuous phase shifts. However, hardware constraints limit the phase shift resolution, manifested into the amount of discrete phase shifts that can be configured into each RIS element. This paper aims to offer a discrete phase shift beamforming algorithm for reflective RISs that targets minimization of the quantization error resulting from discretization of continuous phase shifts. The beamforming solution proves to be optimal under perfect channel knowledge for any discrete set of uniformly distributed phase shifts. The required complexity to find the optimal beamforming vector for our approach is found to be linear with the number of RIS elements, the minimum needed to obtain optimal results. Simulated behavior is validated by measurements, showing robustness against angle misalignments and distance variations. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/889db4c0-c52e-4dd1-a519-ccf6bfe01df7
- author
- Sanchez, Juan
LU
; Bengtsson, Erik L
LU
; Rusek, Fredrik
LU
; Flordelis i Minguez, José
LU
; Zhao, Kun
and Tufvesson, Fredrik
LU
- organization
- publishing date
- 2021-12-08
- type
- Chapter in Book/Report/Conference proceeding
- publication status
- published
- subject
- keywords
- reconfigurable intelligent surface, low complexity, passive beamforming, optimal beamforming, discrete phase shifts, quantization error, experimental validation
- host publication
- 2021 IEEE Global Communications Conference, GLOBECOM 2021 - Proceedings
- pages
- 6 pages
- publisher
- IEEE - Institute of Electrical and Electronics Engineers Inc.
- conference name
- IEEE Global Communications Conference, GLOBECOM 2021
- conference location
- Madrid, Spain
- conference dates
- 2021-12-07 - 2021-12-11
- external identifiers
-
- scopus:85127303825
- ISBN
- 978-172818104-2
- DOI
- 10.1109/GLOBECOM46510.2021.9685226
- language
- English
- LU publication?
- yes
- id
- 889db4c0-c52e-4dd1-a519-ccf6bfe01df7
- date added to LUP
- 2021-12-16 03:39:21
- date last changed
- 2022-05-16 17:00:44
@inproceedings{889db4c0-c52e-4dd1-a519-ccf6bfe01df7,
abstract = {{Reflective reconfigurable intelligent surface (RIS) technology is regarded as an innovative, cost- and power-effective solution that aims at influencing the wireless channel through controlled scattering. The technology can be realized by using metamaterials and/or resonant elements that scatter electromagnetic waves with a configurable phase shift. Most of the previous work on beamforming techniques for RIS assumes ideal hardware and, thus, continuous phase shifts. However, hardware constraints limit the phase shift resolution, manifested into the amount of discrete phase shifts that can be configured into each RIS element. This paper aims to offer a discrete phase shift beamforming algorithm for reflective RISs that targets minimization of the quantization error resulting from discretization of continuous phase shifts. The beamforming solution proves to be optimal under perfect channel knowledge for any discrete set of uniformly distributed phase shifts. The required complexity to find the optimal beamforming vector for our approach is found to be linear with the number of RIS elements, the minimum needed to obtain optimal results. Simulated behavior is validated by measurements, showing robustness against angle misalignments and distance variations.}},
author = {{Sanchez, Juan and Bengtsson, Erik L and Rusek, Fredrik and Flordelis i Minguez, José and Zhao, Kun and Tufvesson, Fredrik}},
booktitle = {{2021 IEEE Global Communications Conference, GLOBECOM 2021 - Proceedings}},
isbn = {{978-172818104-2}},
keywords = {{reconfigurable intelligent surface; low complexity; passive beamforming; optimal beamforming; discrete phase shifts; quantization error; experimental validation}},
language = {{eng}},
month = {{12}},
publisher = {{IEEE - Institute of Electrical and Electronics Engineers Inc.}},
title = {{Optimal, Low-Complexity Beamforming for Discrete Phase Reconfigurable Intelligent Surfaces}},
url = {{https://lup.lub.lu.se/search/files/111043754/2021005109_3_.pdf}},
doi = {{10.1109/GLOBECOM46510.2021.9685226}},
year = {{2021}},
}