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ZTE Communications ›› 2015, Vol. 13 ›› Issue (1): 28-34.DOI: 10.3969/j.issn.1673-5188.2015.01.004

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Energy-Efficient Large-Scale Antenna Systems with Hybrid Digital-Analog Beamforming Structure

Shuangfeng Han1, Chih-Lin I1, Zhikun Xu1, Qi Sun1, and Haibin Li2   

  1. 1. Green Communication Research Center, China Mobile Research Institute, Beijing 100053, China;
    2. Department of Planning and Construction, China Mobile, Beijing 100053, China
  • Received:2014-09-15 Online:2015-03-25 Published:2015-03-25
  • About author:Shuangfeng Han (hanshuangfeng@chinamobile.com) received his MS and PhD degrees in electrical engineering from Tsinghua University in 2002 and 2006. He joined Samsung Electronics as a senior engineer in 2006 and worked on MIMO and MultiBS MIMO. Since 2012, he has been a senior project manager in the Green Communication Research Center of China Mobile Research Institute. His research interests include green 5G, massive MIMO, full-duplex, non-orthogonal multiple access, energy efficiency, and spectral efficiency co-design.
    Chih-Lin I (icl@chinamobile.com) received her PhD degree in electrical engineering from Stanford University. She has worked for numerous world-class companies and research institutes, including AT&T Bell Labs, AT&T HQ, ITRI Taiwan, and ASTRI Hong Kong. She was awarded the Stephen Rice Best Paper Award from IEEE Tranactions on Communications and is a winner of the CCCP National 1000 Talent program. Currently, she is China Mobile’s chief scientist of wireless technologies and has established the Green Communications Research Center, spearheading major initiatives including key 5G technology R&D; high EE system architectures, technologies and devices; green energy; and C-RAN and soft base stations. She was an elected Board Member of IEEE ComSoc, Chair of the ComSoc Meetings and Conferences Board, and Founding Chair of the IEEE WCNC Steering Committee. She is currently an Executive Board Member of GreenTouch and a Network Operator Council Member of ETSI NFV. Her research interests are green communications, C-RAN, network convergence, bandwidth refarming, EE-SE co-design, massive MIMO, and active antenna arrays.
    Zhikun Xu (xuzhikun@chinamobile.com) received his BSE and PhD degrees in signal and information processing from Beihang University (BUAA), China in 2007 and 2013. After graduation, he joined the Green Communication Research Center of China Mobile Research Institute as a project manager. His current interests include green technologies, cross-layer resource allocation, advanced signal processing, and transmission techniques.
    Qi Sun (sunqiyjy@chinamobile.com) received her BSE and PhD degrees in information and communication engineering from Beijing University of Posts and Telecommunications in 2009 and 2014. After graduation, she joined the Green Communication Research Center of China Mobile Research Institute. Her research interests include MIMO, cooperative communication, and green communications.
    Haibin Li (lihaibin@chinamobile.com) received her MS degree in project management from Beijing University of Posts and Telecommunications, China. She is currently the director of Division of Energy Conservation and Emission Reduction, Department of Planning and Construction, China Mobile Communications Corporation. She has been in charge of energy saving and emission reduction from April 2011 and has 19 years experience in the field of communications planning and construction. She is also the director of Resource Sharing Plan for CMCC and deputy head of the CCSA ST2 and ST4 group.

Energy-Efficient Large-Scale Antenna Systems with Hybrid Digital-Analog Beamforming Structure

Shuangfeng Han1, Chih-Lin I1, Zhikun Xu1, Qi Sun1, and Haibin Li2   

  1. 1. Green Communication Research Center, China Mobile Research Institute, Beijing 100053, China;
    2. Department of Planning and Construction, China Mobile, Beijing 100053, China
  • 作者简介:Shuangfeng Han (hanshuangfeng@chinamobile.com) received his MS and PhD degrees in electrical engineering from Tsinghua University in 2002 and 2006. He joined Samsung Electronics as a senior engineer in 2006 and worked on MIMO and MultiBS MIMO. Since 2012, he has been a senior project manager in the Green Communication Research Center of China Mobile Research Institute. His research interests include green 5G, massive MIMO, full-duplex, non-orthogonal multiple access, energy efficiency, and spectral efficiency co-design.
    Chih-Lin I (icl@chinamobile.com) received her PhD degree in electrical engineering from Stanford University. She has worked for numerous world-class companies and research institutes, including AT&T Bell Labs, AT&T HQ, ITRI Taiwan, and ASTRI Hong Kong. She was awarded the Stephen Rice Best Paper Award from IEEE Tranactions on Communications and is a winner of the CCCP National 1000 Talent program. Currently, she is China Mobile’s chief scientist of wireless technologies and has established the Green Communications Research Center, spearheading major initiatives including key 5G technology R&D; high EE system architectures, technologies and devices; green energy; and C-RAN and soft base stations. She was an elected Board Member of IEEE ComSoc, Chair of the ComSoc Meetings and Conferences Board, and Founding Chair of the IEEE WCNC Steering Committee. She is currently an Executive Board Member of GreenTouch and a Network Operator Council Member of ETSI NFV. Her research interests are green communications, C-RAN, network convergence, bandwidth refarming, EE-SE co-design, massive MIMO, and active antenna arrays.
    Zhikun Xu (xuzhikun@chinamobile.com) received his BSE and PhD degrees in signal and information processing from Beihang University (BUAA), China in 2007 and 2013. After graduation, he joined the Green Communication Research Center of China Mobile Research Institute as a project manager. His current interests include green technologies, cross-layer resource allocation, advanced signal processing, and transmission techniques.
    Qi Sun (sunqiyjy@chinamobile.com) received her BSE and PhD degrees in information and communication engineering from Beijing University of Posts and Telecommunications in 2009 and 2014. After graduation, she joined the Green Communication Research Center of China Mobile Research Institute. Her research interests include MIMO, cooperative communication, and green communications.
    Haibin Li (lihaibin@chinamobile.com) received her MS degree in project management from Beijing University of Posts and Telecommunications, China. She is currently the director of Division of Energy Conservation and Emission Reduction, Department of Planning and Construction, China Mobile Communications Corporation. She has been in charge of energy saving and emission reduction from April 2011 and has 19 years experience in the field of communications planning and construction. She is also the director of Resource Sharing Plan for CMCC and deputy head of the CCSA ST2 and ST4 group.

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Abstract: A large-scale antenna system (LSAS) with digital beamforming is expected to significantly increase energy efficiency (EE) and spectral efficiency (SE) in a wireless communication system. However, there are many challenging issues related to calibration, energy consumption, and cost in implementing a digital beamforming structure in an LSAS. In a practical LSAS deployment, hybrid digital-analog beamforming structures with active antennas can be used. In this paper, we investigate the optimal antenna configuration in an N × M beamforming structure, where N is the number of transceivers, M is the number of active antennas per transceiver, where analog beamforming is introduced for individual transceivers and digital beamforming is introduced across all N transceivers. We analyze the green point, which is the point of maximum EE on the EE-SE curve, and show that the log-scale EE scales linearly with SE along a slope of -lg2/N. We investigate the effect of M on EE for a given SE value in the case of fixed NM and independent N and M. In both cases, there is a unique optimal M that results in optimal EE. In the case of independent N and M, there is no optimal (N, M) combination for optimizing EE. The results of numerical simulations are provided, and these results support our analysis.

Key words: digital beamforming, analog beamforming, hybrid beamforming, energy efficiency, spectral efficiency

摘要： A large-scale antenna system (LSAS) with digital beamforming is expected to significantly increase energy efficiency (EE) and spectral efficiency (SE) in a wireless communication system. However, there are many challenging issues related to calibration, energy consumption, and cost in implementing a digital beamforming structure in an LSAS. In a practical LSAS deployment, hybrid digital-analog beamforming structures with active antennas can be used. In this paper, we investigate the optimal antenna configuration in an N × M beamforming structure, where N is the number of transceivers, M is the number of active antennas per transceiver, where analog beamforming is introduced for individual transceivers and digital beamforming is introduced across all N transceivers. We analyze the green point, which is the point of maximum EE on the EE-SE curve, and show that the log-scale EE scales linearly with SE along a slope of -lg2/N. We investigate the effect of M on EE for a given SE value in the case of fixed NM and independent N and M. In both cases, there is a unique optimal M that results in optimal EE. In the case of independent N and M, there is no optimal (N, M) combination for optimizing EE. The results of numerical simulations are provided, and these results support our analysis.

关键词: digital beamforming, analog beamforming, hybrid beamforming, energy efficiency, spectral efficiency