TY - JOUR
T1 - Initial Beam Association in Millimeter Wave Cellular Systems
T2 - Analysis and Design Insights
AU - Alkhateeb, Ahmed
AU - Nam, Young Han
AU - Rahman, Md Saifur
AU - Zhang, Jianzhong
AU - Heath, Robert W.
N1 - Funding Information:
Manuscript received February 22, 2016; revised July 27, 2016 and December 30, 2016; accepted January 23, 2017. Date of publication March 17, 2017; date of current version May 8, 2017. The work of A. Alkhateeb and R. W. Heath, Jr. was supported by the National Science Foundation under Grant 1319556. The associate editor coordinating the review of this paper and approving it for publication was Y. Jing.
Publisher Copyright:
© 2002-2012 IEEE.
PY - 2017/5
Y1 - 2017/5
N2 - Enabling the high data rates of millimeter wave (mmWave) cellular systems requires deploying large antenna arrays at both the basestations and mobile users. Prior work on coverage and rate of mmWave cellular networks focused on the case when basestations and mobile beamforming vectors are predesigned for maximum beamforming gains. Designing beamforming/combining vectors, though, requires training, which may impact both the SINR coverage and rate of mmWave systems. This paper evaluates mmWave cellular network performance while accounting for the beam training/association overhead. First, a model for the initial beam association is developed based on beam sweeping and downlink control pilot reuse. To incorporate the impact of beam training, a new metric, called the effective reliable rate, is defined and adopted. Using stochastic geometry, the effective rate of mmWave cellular networks is derived for two special cases: near-orthogonal pilots and full pilot reuse. Analytical and simulation results provide insights into the answers of two important questions. First, what is the impact of beam association on mmWave network performance? Then, should orthogonal or reused pilots be employed? The results show that unless the employed beams are very wide, initial beam training with full pilot reuse is nearly as good as perfect beam alignment.
AB - Enabling the high data rates of millimeter wave (mmWave) cellular systems requires deploying large antenna arrays at both the basestations and mobile users. Prior work on coverage and rate of mmWave cellular networks focused on the case when basestations and mobile beamforming vectors are predesigned for maximum beamforming gains. Designing beamforming/combining vectors, though, requires training, which may impact both the SINR coverage and rate of mmWave systems. This paper evaluates mmWave cellular network performance while accounting for the beam training/association overhead. First, a model for the initial beam association is developed based on beam sweeping and downlink control pilot reuse. To incorporate the impact of beam training, a new metric, called the effective reliable rate, is defined and adopted. Using stochastic geometry, the effective rate of mmWave cellular networks is derived for two special cases: near-orthogonal pilots and full pilot reuse. Analytical and simulation results provide insights into the answers of two important questions. First, what is the impact of beam association on mmWave network performance? Then, should orthogonal or reused pilots be employed? The results show that unless the employed beams are very wide, initial beam training with full pilot reuse is nearly as good as perfect beam alignment.
KW - Millimeter wave cellular systems
KW - beam association
KW - initial access
KW - stochastic geometry
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U2 - 10.1109/TWC.2017.2666806
DO - 10.1109/TWC.2017.2666806
M3 - Article
AN - SCOPUS:85028703511
SN - 1536-1276
VL - 16
SP - 2807
EP - 2821
JO - IEEE Transactions on Wireless Communications
JF - IEEE Transactions on Wireless Communications
IS - 5
M1 - 7880676
ER -