Multicell MIMO communications relying on intelligent reflecting surfaces
Multicell MIMO communications relying on intelligent reflecting surfaces
Intelligent reflecting surfaces (IRSs) constitute a disruptive wireless communication technique capable of creating a controllable propagation environment. In this paper, we propose to invoke an IRS at the cell boundary of multiple cells to assist the downlink transmission to cell-edge users, whilst mitigating the inter-cell interference, which is a crucial issue in multicell communication systems. We aim for maximizing the weighted sum rate (WSR) of all users through jointly optimizing the active precoding matrices at the base stations (BSs) and the phase shifts at the IRS subject to each BS's power constraint and unit modulus constraint. Both the BSs and the users are equipped with multiple antennas, which enhances the spectral efficiency by exploiting the spatial multiplexing gain. Due to the non-convexity of the problem, we first reformulate it into an equivalent one, which is solved by using the block coordinate descent (BCD) algorithm, where the precoding matrices and phase shifts are alternately optimized. The optimal precoding matrices can be obtained in closed form, when fixing the phase shifts. A pair of efficient algorithms are proposed for solving the phase shift optimization problem, namely the Majorization-Minimization (MM) Algorithm and the Complex Circle Manifold (CCM) Method. Both algorithms are guaranteed to converge to at least locally optimal solutions. We also extend the proposed algorithms to the more general multiple-IRS and network MIMO scenarios. Finally, our simulation results confirm the advantages of introducing IRSs in enhancing the cell-edge user performance.
Intelligent reflecting surface (IRS), manifold optimization, MIMO, multicell communications, reconfigurable intelligent surfaces
5218-5233
Pan, Cunhua
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Ren, Hong
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Wang, Kezhi
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Xu, Wei
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Elkashlan, Maged
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Nallanathan, Arumugam
d255cda5-a015-4bb9-9f17-88614a544396
Hanzo, Lajos
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1 August 2020
Pan, Cunhua
9ee3d968-c5c2-42ba-8041-d54667205d5b
Ren, Hong
0cd70e56-a7d7-478e-bcd8-54c13866bb48
Wang, Kezhi
338ae80c-5b3d-4c9b-b536-f8def4b858b5
Xu, Wei
d012c621-8510-4ac3-bd83-9da7515b98d2
Elkashlan, Maged
27c756ff-bfd3-4844-8769-ace5ad28c840
Nallanathan, Arumugam
d255cda5-a015-4bb9-9f17-88614a544396
Hanzo, Lajos
66e7266f-3066-4fc0-8391-e000acce71a1
Pan, Cunhua, Ren, Hong, Wang, Kezhi, Xu, Wei, Elkashlan, Maged, Nallanathan, Arumugam and Hanzo, Lajos
(2020)
Multicell MIMO communications relying on intelligent reflecting surfaces.
IEEE Transactions on Wireless Communications, 19 (8), , [9090356].
(doi:10.1109/TWC.2020.2990766).
Abstract
Intelligent reflecting surfaces (IRSs) constitute a disruptive wireless communication technique capable of creating a controllable propagation environment. In this paper, we propose to invoke an IRS at the cell boundary of multiple cells to assist the downlink transmission to cell-edge users, whilst mitigating the inter-cell interference, which is a crucial issue in multicell communication systems. We aim for maximizing the weighted sum rate (WSR) of all users through jointly optimizing the active precoding matrices at the base stations (BSs) and the phase shifts at the IRS subject to each BS's power constraint and unit modulus constraint. Both the BSs and the users are equipped with multiple antennas, which enhances the spectral efficiency by exploiting the spatial multiplexing gain. Due to the non-convexity of the problem, we first reformulate it into an equivalent one, which is solved by using the block coordinate descent (BCD) algorithm, where the precoding matrices and phase shifts are alternately optimized. The optimal precoding matrices can be obtained in closed form, when fixing the phase shifts. A pair of efficient algorithms are proposed for solving the phase shift optimization problem, namely the Majorization-Minimization (MM) Algorithm and the Complex Circle Manifold (CCM) Method. Both algorithms are guaranteed to converge to at least locally optimal solutions. We also extend the proposed algorithms to the more general multiple-IRS and network MIMO scenarios. Finally, our simulation results confirm the advantages of introducing IRSs in enhancing the cell-edge user performance.
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Accepted/In Press date: 23 April 2020
e-pub ahead of print date: 8 May 2020
Published date: 1 August 2020
Additional Information:
Funding Information:
Manuscript received August 31, 2019; revised March 7, 2020; accepted April 23, 2020. Date of publication May 8, 2020; date of current version August 12, 2020. The work of Wei Xu was supported by the NSFC under Grant 61941115 and Grant 61871109. The work of Arumugam Nallanathan was supported by the U.K., Engineering and the Physical Sciences Research Council under Grant EP/N029666/1. L. Hanzo would like to acknowledge the financial support of the Engineering and Physical Sciences Research Council projects EP/N004558/1, EP/P034284/1, EP/P034284/1, EP/P003990/1 (COALESCE), of the Royal Society’s Global Challenges Research Fund Grant as well as of the European Research Council’s Advanced Fellow Grant QuantCom. The associate editor coordinating the review of this article and approving it for publication was M. S. Alouini. (Corresponding authors: Hong Ren; Lajos Hanzo.) Cunhua Pan, Hong Ren, Maged Elkashlan, and Arumugam Nallanathan are with the School of Electronic Engineering and Computer Science, Queen Mary University of London, London E1 4NS, U.K. (e-mail: c.pan@qmul. ac.uk; h.ren@qmul.ac.uk; maged.elkashlan@qmul.ac.uk; a.nallanathan@ qmul.ac.uk).
Publisher Copyright:
© 2002-2012 IEEE.
Keywords:
Intelligent reflecting surface (IRS), manifold optimization, MIMO, multicell communications, reconfigurable intelligent surfaces
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Local EPrints ID: 439684
URI: http://eprints.soton.ac.uk/id/eprint/439684
ISSN: 1536-1276
PURE UUID: eea52a86-673d-455e-9107-b42fd8362e50
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Date deposited: 29 Apr 2020 16:31
Last modified: 18 Mar 2024 02:36
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Author:
Cunhua Pan
Author:
Hong Ren
Author:
Kezhi Wang
Author:
Wei Xu
Author:
Maged Elkashlan
Author:
Arumugam Nallanathan
Author:
Lajos Hanzo
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