Benefits of Beamforming Training Scheme in Distributed Large-Scale MIMO Systems

The downlink training yields rather modest performance gains due to the high degree of channel hardening effect in co-located large-scale multi-input multi-output (MIMO) systems. However, in distributed large-scale MIMO systems, the potential benefits of the downlink training become larger, since there is a high probability that each user is very close to only a part of remote antenna units and is effectively served by them which results in less channel hardening effect. In this paper, we study the benefits of the beamforming training (BT) scheme (users estimate the channel state information by using the received training symbols, which are processed by linear beamforming in advance) in distributed large-scale MIMO systems. We derive accurate and tractable closed-form analytical expressions for the spectral efficiency (SE) of the BT scheme in distributed large-scale MIMO systems with maximum ratio transmission and zero-forcing (ZF) beamforming. Based on these expressions, we analyze the benefits of the BT scheme and investigate how the number of transmit antennas and the length of coherence interval affect the SE of the BT scheme in the co-located and distributed large-scale MIMO systems. The analytical results show that the BT scheme is more suitable for distributed large-scale MIMO systems with ZF beamforming, and a less number of transmit antennas and longer coherence interval can improve the performance gain of BT scheme.

[1]  Wei-Ping Zhu,et al.  Optimal Beamformer Design for Dual-Hop MIMO AF Relay Networks over Rayleigh Fading Channels , 2012, IEEE Journal on Selected Areas in Communications.

[2]  Huiling Zhu,et al.  Performance Comparison Between Distributed Antenna and Microcellular Systems , 2011, IEEE Journal on Selected Areas in Communications.

[3]  Emil Björnson,et al.  Linear Precoding Based on Polynomial Expansion: Large-Scale Multi-Cell MIMO Systems , 2013, IEEE Journal of Selected Topics in Signal Processing.

[4]  Xiaohu You,et al.  An overview of transmission theory and techniques of large-scale antenna systems for 5G wireless communications , 2016, Science China Information Sciences.

[5]  Sooyong Choi,et al.  Study on effect of training for downlink massive MIMO systems with outdated channel , 2015, 2015 IEEE International Conference on Communications (ICC).

[6]  S. Kay.  Fundamentals of statistical signal processing: estimation theory , 1993 .

[7]  Xiaohu You,et al.  Spectral efficiency analysis of large-scale distributed antenna system in a composite correlated Rayleigh fading channel , 2015, IET Commun..

[8]  Emil Björnson,et al.  Massive MIMO: ten myths and one critical question , 2015, IEEE Communications Magazine.

[9]  Erik G. Larsson,et al.  Scaling Up MIMO: Opportunities and Challenges with Very Large Arrays , 2012, IEEE Signal Process. Mag..

[10]  Wei Yu,et al.  Modeling and analysis of ergodic capacity in network MIMO systems , 2014, 2014 IEEE Globecom Workshops (GC Wkshps).

[11]  Wei Yu,et al.  A Stochastic Analysis of Network MIMO Systems , 2016, IEEE Transactions on Signal Processing.

[12]  Robert W. Heath,et al.  Multiuser MIMO in Distributed Antenna Systems With Out-of-Cell Interference , 2011, IEEE Transactions on Signal Processing.

[13]  Giuseppe Caire,et al.  Performance Analysis of Massive MIMO for Cell-Boundary Users , 2013, IEEE Transactions on Wireless Communications.

[14]  Tommy Svensson,et al.  Adaptive Multicell 3D Beamforming in Multi-Antenna Cellular Networks , 2014 .

[15]  Erik G. Larsson,et al.  Massive MIMO for next generation wireless systems , 2013, IEEE Communications Magazine.

[16]  Xiaohu You,et al.  Downlink spectral efficiency of multi-cell multi-user large-scale DAS with pilot contamination , 2015, 2015 IEEE International Conference on Communications (ICC).

[17]  Chau Yuen,et al.  Multicell Multiuser Massive MIMO Transmission With Downlink Training and Pilot Contamination Precoding , 2016, IEEE Transactions on Vehicular Technology.

[18]  Emil Björnson,et al.  Massive MIMO with Non-Ideal Arbitrary Arrays: Hardware Scaling Laws and Circuit-Aware Design , 2014, IEEE Transactions on Wireless Communications.

[19]  Wei-Ping Zhu,et al.  Joint Beamforming and Power Control for Device-to-Device Communications Underlaying Cellular Networks , 2016, IEEE Journal on Selected Areas in Communications.

[20]  Geoffrey Ye Li,et al.  An Overview of Massive MIMO: Benefits and Challenges , 2014, IEEE Journal of Selected Topics in Signal Processing.

[21]  Amin Khansefid,et al.  Achievable Downlink Rates of MRC and ZF Precoders in Massive MIMO With Uplink and Downlink Pilot Contamination , 2015, IEEE Transactions on Communications.

[22]  Ming Chen,et al.  Cooperative distributed antenna systems for mobile communications [Coordinated and Distributed MIMO] , 2010, IEEE Wireless Communications.

[23]  Erik G. Larsson,et al.  How Much Do Downlink Pilots Improve Cell-Free Massive MIMO? , 2016, 2016 IEEE Global Communications Conference (GLOBECOM).

[24]  Xiaohu You,et al.  Downlink Spectral Efficiency of Distributed Massive MIMO Systems With Linear Beamforming Under Pilot Contamination , 2017, IEEE Transactions on Vehicular Technology.

[25]  Lin Dai.  An Uplink Capacity Analysis of the Distributed Antenna System (DAS): From Cellular DAS to DAS with Virtual Cells , 2014, IEEE Transactions on Wireless Communications.

[26]  Erwin Riegler,et al.  Optimum MIMO-OFDM Detection With Pilot-Aided Channel State Information , 2009, IEEE Journal of Selected Topics in Signal Processing.

[27]  Jiangzhou Wang,et al.  Uplink Spectral Efficiency Analysis of In-Building Distributed Antenna Systems , 2015, IEEE Transactions on Wireless Communications.

[28]  Wei Yu,et al.  Large-scale MIMO versus network MIMO for multicell interference mitigation , 2014, 2014 IEEE 15th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC).

[29]  Mérouane Debbah,et al.  Massive MIMO in the UL/DL of Cellular Networks: How Many Antennas Do We Need? , 2013, IEEE Journal on Selected Areas in Communications.

[30]  Emil Björnson,et al.  Joint Power Allocation and User Association Optimization for Massive MIMO Systems , 2016, IEEE Transactions on Wireless Communications.

[31]  Emil Björnson,et al.  Massive MIMO for Maximal Spectral Efficiency: How Many Users and Pilots Should Be Allocated? , 2014, IEEE Transactions on Wireless Communications.

[32]  Jeffrey G. Andrews,et al.  Downlink performance and capacity of distributed antenna systems in a multicell environment , 2007, IEEE Transactions on Wireless Communications.

[33]  Thomas L. Marzetta,et al.  Pilot Contamination and Precoding in Multi-Cell TDD Systems , 2009, IEEE Transactions on Wireless Communications.

[34]  Thomas L. Marzetta,et al.  Noncooperative Cellular Wireless with Unlimited Numbers of Base Station Antennas , 2010, IEEE Transactions on Wireless Communications.

[35]  Lin Dai.  A Comparative Study on Uplink Sum Capacity with Co-Located and Distributed Antennas , 2011, IEEE Journal on Selected Areas in Communications.

[36]  Tommy Svensson,et al.  Joint transmission mode and tilt adaptation in coordinated small-cell networks , 2014, 2014 IEEE International Conference on Communications Workshops (ICC).

[37]  Erik G. Larsson,et al.  Massive MU-MIMO downlink TDD systems with linear precoding and downlink pilots , 2013, 2013 51st Annual Allerton Conference on Communication, Control, and Computing (Allerton).