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On the Downlink Capacity of Cell-Free Massive MIMO with Constrained Fronthaul Capacity
We investigate the downlink of a cell-free massive multiple-in multiple-out system in which all access points (APs) are connected in a linear-topolpgy fronthaul with constrained capacity and send a common message to a single receiver. By modeling the system as an extension of the multiple-access cha...
Autores principales: | , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2020
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7516895/ https://www.ncbi.nlm.nih.gov/pubmed/33286191 http://dx.doi.org/10.3390/e22040418 |
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author | Zhang, Peng Willems, Frans M. J. |
author_facet | Zhang, Peng Willems, Frans M. J. |
author_sort | Zhang, Peng |
collection | PubMed |
description | We investigate the downlink of a cell-free massive multiple-in multiple-out system in which all access points (APs) are connected in a linear-topolpgy fronthaul with constrained capacity and send a common message to a single receiver. By modeling the system as an extension of the multiple-access channel with partially cooperating encoders, we derive the channel capacity of the two-AP setting and then extend the results to arbitrary N-AP scenarios. By developing a cooperating mode concept, we investigate the optimal cooperation among the encoders (APs) when we limit the total fronthaul capacity, and the total transmit power is constrained as well. It is demonstrated that achieving capacity requires a water-pouring distribution of the total available fronthaul capacity over the fronthaul links. Our study reveals that a linear growth of total fronthaul capacity results in a logarithmic growth of the beamforming capacity. Moreover, even if the number of APs would be unlimited, only a finite number of them need to be activated. We found an expression for this number. |
format | Online Article Text |
id | pubmed-7516895 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-75168952020-11-09 On the Downlink Capacity of Cell-Free Massive MIMO with Constrained Fronthaul Capacity Zhang, Peng Willems, Frans M. J. Entropy (Basel) Article We investigate the downlink of a cell-free massive multiple-in multiple-out system in which all access points (APs) are connected in a linear-topolpgy fronthaul with constrained capacity and send a common message to a single receiver. By modeling the system as an extension of the multiple-access channel with partially cooperating encoders, we derive the channel capacity of the two-AP setting and then extend the results to arbitrary N-AP scenarios. By developing a cooperating mode concept, we investigate the optimal cooperation among the encoders (APs) when we limit the total fronthaul capacity, and the total transmit power is constrained as well. It is demonstrated that achieving capacity requires a water-pouring distribution of the total available fronthaul capacity over the fronthaul links. Our study reveals that a linear growth of total fronthaul capacity results in a logarithmic growth of the beamforming capacity. Moreover, even if the number of APs would be unlimited, only a finite number of them need to be activated. We found an expression for this number. MDPI 2020-04-07 /pmc/articles/PMC7516895/ /pubmed/33286191 http://dx.doi.org/10.3390/e22040418 Text en © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Zhang, Peng Willems, Frans M. J. On the Downlink Capacity of Cell-Free Massive MIMO with Constrained Fronthaul Capacity |
title | On the Downlink Capacity of Cell-Free Massive MIMO with Constrained Fronthaul Capacity |
title_full | On the Downlink Capacity of Cell-Free Massive MIMO with Constrained Fronthaul Capacity |
title_fullStr | On the Downlink Capacity of Cell-Free Massive MIMO with Constrained Fronthaul Capacity |
title_full_unstemmed | On the Downlink Capacity of Cell-Free Massive MIMO with Constrained Fronthaul Capacity |
title_short | On the Downlink Capacity of Cell-Free Massive MIMO with Constrained Fronthaul Capacity |
title_sort | on the downlink capacity of cell-free massive mimo with constrained fronthaul capacity |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7516895/ https://www.ncbi.nlm.nih.gov/pubmed/33286191 http://dx.doi.org/10.3390/e22040418 |
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