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Feedback bit allocation for large distributed antenna systems in indoor WLAN

Massive MIMO is a key technique for next generation wireless networks due to its potential for significant capacity improvement. To achieve good performance, accurate channel state information (CSI) is needed, especially at the transmitter, to calculate the beamforming matrices. This problem exists...

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Main Authors:	Wang, Q., Debbarma, D., Lo, A., Niemegeers, I., De Groot, S. H.
Format:	Conference or Workshop Item
Published:	Institute of Electrical and Electronics Engineers Inc. 2016
Subjects:	QA Mathematics QA75 Electronic computers. Computer science
Online Access:	http://eprints.utm.my/id/eprint/73476/ https://www.scopus.com/inward/record.uri?eid=2-s2.0-84964894833&doi=10.1109%2fSCVT.2015.7374230&partnerID=40&md5=3d2e282c64207029b3b3ad9d1a1f90a7
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spelling	my.utm.734762017-11-20T08:43:00Z http://eprints.utm.my/id/eprint/73476/ Feedback bit allocation for large distributed antenna systems in indoor WLAN Wang, Q. Debbarma, D. Lo, A. Niemegeers, I. De Groot, S. H. QA Mathematics QA75 Electronic computers. Computer science Massive MIMO is a key technique for next generation wireless networks due to its potential for significant capacity improvement. To achieve good performance, accurate channel state information (CSI) is needed, especially at the transmitter, to calculate the beamforming matrices. This problem exists for traditional MIMO systems and becomes more challenging for Massive MIMO as the number of antennas is much larger. In this paper, we focus on Massive MIMO with distributed antenna system (DAS) architecture, which we refer as large DAS. In a large DAS, a large number of remote antenna units (RAUs), each equipped with a small antenna array, are distributed over the service area, cooperatively working for beamforming. Due to the large separation of the RAUs, the large scale fading factors of the RAUs for a given mobile station (STA) is different. This effect can be utilized for optimizing the feedback bit allocation considering that more bits should be allocated to dominant signal paths. So we propose two bit allocation algorithms, one that adaptively allocates different bits to the RAUs according to the large scale fading, termed adaptive allocation; and the other that allocates equal bits to a set of RAUs, termed equal allocation. They are applied for centralized and de-centralized zero-forcing beamforming (C- and D-ZFBF) respectively. The results show that with a proper bit allocation, the data rates can approximate that of perfect CSI with limited feedback rate. For C-ZFBF, adaptive allocation performs better than equal allocation with medium feedback rates, and similarly for low and high feedback rates. For D-ZFBF, adaptive allocation and equal allocation offer similar results. Institute of Electrical and Electronics Engineers Inc. 2016 Conference or Workshop Item PeerReviewed Wang, Q. and Debbarma, D. and Lo, A. and Niemegeers, I. and De Groot, S. H. (2016) Feedback bit allocation for large distributed antenna systems in indoor WLAN. In: 22nd IEEE Symposium on Communications and Vehicular Technology in the Benelux, SCVT 2015, 24 Nov 2015, Luxembourg. https://www.scopus.com/inward/record.uri?eid=2-s2.0-84964894833&doi=10.1109%2fSCVT.2015.7374230&partnerID=40&md5=3d2e282c64207029b3b3ad9d1a1f90a7
institution	Universiti Teknologi Malaysia
building	UTM Library
collection	Institutional Repository
continent	Asia
country	Malaysia
content_provider	Universiti Teknologi Malaysia
content_source	UTM Institutional Repository
url_provider	http://eprints.utm.my/
topic	QA Mathematics QA75 Electronic computers. Computer science
spellingShingle	QA Mathematics QA75 Electronic computers. Computer science Wang, Q. Debbarma, D. Lo, A. Niemegeers, I. De Groot, S. H. Feedback bit allocation for large distributed antenna systems in indoor WLAN
description	Massive MIMO is a key technique for next generation wireless networks due to its potential for significant capacity improvement. To achieve good performance, accurate channel state information (CSI) is needed, especially at the transmitter, to calculate the beamforming matrices. This problem exists for traditional MIMO systems and becomes more challenging for Massive MIMO as the number of antennas is much larger. In this paper, we focus on Massive MIMO with distributed antenna system (DAS) architecture, which we refer as large DAS. In a large DAS, a large number of remote antenna units (RAUs), each equipped with a small antenna array, are distributed over the service area, cooperatively working for beamforming. Due to the large separation of the RAUs, the large scale fading factors of the RAUs for a given mobile station (STA) is different. This effect can be utilized for optimizing the feedback bit allocation considering that more bits should be allocated to dominant signal paths. So we propose two bit allocation algorithms, one that adaptively allocates different bits to the RAUs according to the large scale fading, termed adaptive allocation; and the other that allocates equal bits to a set of RAUs, termed equal allocation. They are applied for centralized and de-centralized zero-forcing beamforming (C- and D-ZFBF) respectively. The results show that with a proper bit allocation, the data rates can approximate that of perfect CSI with limited feedback rate. For C-ZFBF, adaptive allocation performs better than equal allocation with medium feedback rates, and similarly for low and high feedback rates. For D-ZFBF, adaptive allocation and equal allocation offer similar results.
format	Conference or Workshop Item
author	Wang, Q. Debbarma, D. Lo, A. Niemegeers, I. De Groot, S. H.
author_facet	Wang, Q. Debbarma, D. Lo, A. Niemegeers, I. De Groot, S. H.
author_sort	Wang, Q.
title	Feedback bit allocation for large distributed antenna systems in indoor WLAN
title_short	Feedback bit allocation for large distributed antenna systems in indoor WLAN
title_full	Feedback bit allocation for large distributed antenna systems in indoor WLAN
title_fullStr	Feedback bit allocation for large distributed antenna systems in indoor WLAN
title_full_unstemmed	Feedback bit allocation for large distributed antenna systems in indoor WLAN
title_sort	feedback bit allocation for large distributed antenna systems in indoor wlan
publisher	Institute of Electrical and Electronics Engineers Inc.
publishDate	2016
url	http://eprints.utm.my/id/eprint/73476/ https://www.scopus.com/inward/record.uri?eid=2-s2.0-84964894833&doi=10.1109%2fSCVT.2015.7374230&partnerID=40&md5=3d2e282c64207029b3b3ad9d1a1f90a7
_version_	1643656670770888704
score	13.211869

Feedback bit allocation for large distributed antenna systems in indoor WLAN

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