TY - JOUR
T1 - Heterogeneous cellular networks with los and nlos transmissions-The role of massive MIMO and small cells
AU - Zhang, Qi
AU - Yang, Howard H.
AU - Quek, Tony Q.S.
AU - Lee, Jemin
N1 - Funding Information:
Manuscript received December 30, 2016; revised May 17, 2017 and August 3, 2017; accepted September 12, 2017. Date of publication September 29, 2017; date of current version December 8, 2017. This work was supported in part by the MOE ARF Tier 2 under Grant MOE2015-T2-2-104 and in part by the Zhejiang Provincial Public Technology Research of China under Grant 2016C31063. The work of J. Lee was supported in part by the National Research Foundation of Korea through the Korea Government (MSIP) under Grant 2017R1C1B2009280, in part by the Institute for Information and Communications Technology Promotion through the Korea Government, Resilient Cyber-Physical Systems Research, under Grant 2014-0-00065, and in part by the DGIST Research and Development Program of the Ministry of Science and ICT under Grant 17-ST-02. The associate editor coordinating the review of this paper and approving it for publication was W. Gerstacker. (Corresponding author: Jemin Lee.) Q. Zhang and H. H. Yang are with the Department of Information Systems Technology and Design, Singapore University of Technology and Design, Singapore 487372 (e-mail: qi_zhang@sutd.edu.sg; eehowardh@gmail.com).
Publisher Copyright:
© 2017 IEEE.
PY - 2017/12
Y1 - 2017/12
N2 - We develop a framework for downlink heterogeneous cellular networks with line-of-sight (LoS) and non-LoS transmissions. Using stochastic geometry, we derive tight approximation of average downlink rate that enables us to compare the performance between densifying small cells and expanding base station (BS) antenna arrays. Interestingly, we find that adding small cells into the network improves the downlink rate much faster than expanding antenna arrays at the macro BS. However, when the small cell density exceeds a critical threshold, the spatial densification will lose its benefits and further impair the network capacity. To this end, we provide the optimal small cell density that maximizes the rate via numerical results for practical deployment guidance. In contrast, expanding macro BS antenna array can always benefit the capacity until an upper bound caused by pilot contamination, and this bound also surpasses the peak rate obtained from the deployment of small cells. Furthermore, we find that allocating part of antennas to distributed small cell BSS works better than centralizing all antennas at the macro BS, and the optimal allocation proportion is also given numerically for practical configuration reference. In summary, this paper provides a further understanding on how to leverage small cells and massive MIMO in future heterogeneous cellular networks deployment.
AB - We develop a framework for downlink heterogeneous cellular networks with line-of-sight (LoS) and non-LoS transmissions. Using stochastic geometry, we derive tight approximation of average downlink rate that enables us to compare the performance between densifying small cells and expanding base station (BS) antenna arrays. Interestingly, we find that adding small cells into the network improves the downlink rate much faster than expanding antenna arrays at the macro BS. However, when the small cell density exceeds a critical threshold, the spatial densification will lose its benefits and further impair the network capacity. To this end, we provide the optimal small cell density that maximizes the rate via numerical results for practical deployment guidance. In contrast, expanding macro BS antenna array can always benefit the capacity until an upper bound caused by pilot contamination, and this bound also surpasses the peak rate obtained from the deployment of small cells. Furthermore, we find that allocating part of antennas to distributed small cell BSS works better than centralizing all antennas at the macro BS, and the optimal allocation proportion is also given numerically for practical configuration reference. In summary, this paper provides a further understanding on how to leverage small cells and massive MIMO in future heterogeneous cellular networks deployment.
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U2 - 10.1109/TWC.2017.2756044
DO - 10.1109/TWC.2017.2756044
M3 - Article
AN - SCOPUS:85030792547
VL - 16
SP - 7996
EP - 8010
JO - IEEE Transactions on Wireless Communications
JF - IEEE Transactions on Wireless Communications
SN - 1536-1276
IS - 12
ER -