Outage-Constrained Beamforming for Two-Tier Massive MIMO Downlink with Pilot Reuse

Massive multiple-input multiple-output (MIMO) systems and small cell networks are both regarded as promising candidates to meet the exponential growth of mobile data traffic for the next generation (5G) wireless communications. Hence, a new kind of multitier networks which combine massive MIMO macro...

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Main Authors: Guozhen Xu, An Liu, Wei Jiang, Haige Xiang, Wu Luo
Format: Article
Language:English
Published: Wiley 2015-01-01
Series:International Journal of Antennas and Propagation
Online Access:http://dx.doi.org/10.1155/2015/840142
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author Guozhen Xu
An Liu
Wei Jiang
Haige Xiang
Wu Luo
author_facet Guozhen Xu
An Liu
Wei Jiang
Haige Xiang
Wu Luo
author_sort Guozhen Xu
collection DOAJ
description Massive multiple-input multiple-output (MIMO) systems and small cell networks are both regarded as promising candidates to meet the exponential growth of mobile data traffic for the next generation (5G) wireless communications. Hence, a new kind of multitier networks which combine massive MIMO macro cells with a secondary tier of small cells is proposed to resolve the contradiction of large network coverage and high data rate. In such multitier networks, it is inevitable to allocate nonorthogonal uplink pilot sequences to user equipment (UE) due to the large number of users. We propose a pilot reuse scheme by exploiting the unique architecture of this networks and analyse the special mixed channel state information (CSI) yielded by the pilot reuse scheme. Based on the mixed CSI, we formulate a downlink transmit beamforming problem of minimizing the total power consumption while satisfying the quality of service (QoS) requirements with outage constraints. After decomposing the original problem into simpler subproblems, we provide an efficient algorithm to combine these subproblems and solve them iteratively for generating the beamforming vectors. Monte Carlo simulations show that the average power consumption of the proposed pilot reuse scheme and its associated beamforming algorithm is close to that of the perfect CSI case.
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series International Journal of Antennas and Propagation
spelling doaj-art-96bc9f0b9ee84d9ea67fa94c98fe787d2025-08-20T02:09:52ZengWileyInternational Journal of Antennas and Propagation1687-58691687-58772015-01-01201510.1155/2015/840142840142Outage-Constrained Beamforming for Two-Tier Massive MIMO Downlink with Pilot ReuseGuozhen Xu0An Liu1Wei Jiang2Haige Xiang3Wu Luo4The State Key Laboratory of Advanced Optical Communication Systems and Networks, Peking University, Beijing 100871, ChinaDepartment of Electrical and Computer Engineering, Hong Kong University of Science and Technology, Hong KongThe State Key Laboratory of Advanced Optical Communication Systems and Networks, Peking University, Beijing 100871, ChinaThe State Key Laboratory of Advanced Optical Communication Systems and Networks, Peking University, Beijing 100871, ChinaThe State Key Laboratory of Advanced Optical Communication Systems and Networks, Peking University, Beijing 100871, ChinaMassive multiple-input multiple-output (MIMO) systems and small cell networks are both regarded as promising candidates to meet the exponential growth of mobile data traffic for the next generation (5G) wireless communications. Hence, a new kind of multitier networks which combine massive MIMO macro cells with a secondary tier of small cells is proposed to resolve the contradiction of large network coverage and high data rate. In such multitier networks, it is inevitable to allocate nonorthogonal uplink pilot sequences to user equipment (UE) due to the large number of users. We propose a pilot reuse scheme by exploiting the unique architecture of this networks and analyse the special mixed channel state information (CSI) yielded by the pilot reuse scheme. Based on the mixed CSI, we formulate a downlink transmit beamforming problem of minimizing the total power consumption while satisfying the quality of service (QoS) requirements with outage constraints. After decomposing the original problem into simpler subproblems, we provide an efficient algorithm to combine these subproblems and solve them iteratively for generating the beamforming vectors. Monte Carlo simulations show that the average power consumption of the proposed pilot reuse scheme and its associated beamforming algorithm is close to that of the perfect CSI case.http://dx.doi.org/10.1155/2015/840142
spellingShingle Guozhen Xu
An Liu
Wei Jiang
Haige Xiang
Wu Luo
Outage-Constrained Beamforming for Two-Tier Massive MIMO Downlink with Pilot Reuse
International Journal of Antennas and Propagation
title Outage-Constrained Beamforming for Two-Tier Massive MIMO Downlink with Pilot Reuse
title_full Outage-Constrained Beamforming for Two-Tier Massive MIMO Downlink with Pilot Reuse
title_fullStr Outage-Constrained Beamforming for Two-Tier Massive MIMO Downlink with Pilot Reuse
title_full_unstemmed Outage-Constrained Beamforming for Two-Tier Massive MIMO Downlink with Pilot Reuse
title_short Outage-Constrained Beamforming for Two-Tier Massive MIMO Downlink with Pilot Reuse
title_sort outage constrained beamforming for two tier massive mimo downlink with pilot reuse
url http://dx.doi.org/10.1155/2015/840142
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AT anliu outageconstrainedbeamformingfortwotiermassivemimodownlinkwithpilotreuse
AT weijiang outageconstrainedbeamformingfortwotiermassivemimodownlinkwithpilotreuse
AT haigexiang outageconstrainedbeamformingfortwotiermassivemimodownlinkwithpilotreuse
AT wuluo outageconstrainedbeamformingfortwotiermassivemimodownlinkwithpilotreuse