Least-Squares Pilot Sequence Design for TDD Massive MIMO Systems under Inter-Cell Timing Misalignment

Wen Hsuan Li, Jwo-Yuh Wu, Chia Kang Hsu, Li-Chun Wang

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Pilot contamination (PC) is known as a dominant factor for the performance of time-division duplex massive MIMO systems. Most of the existing studies of PC assumed perfect inter-cell synchronization, which is too costly to achieve or even impossible in practice. In this paper, we consider the unsynchronized scenario, in which the reused pilot signals from other cells are subject to timing misalignment, and propose a method for pilot sequence design for reducing the mean square error (MSE) of the linear least squares (LS) channel estimation. An analytic MSE formula is first derived, which is a very complicated function of the pilot coefficients. To ease analysis, an upper bound on the MSE is then derived. Through minimization of this upper bound, an analytic solution is obtained. Computer simulations are used to illustrate the performance of the proposed pilot sequence.

Original languageEnglish
Title of host publication2018 IEEE 29th Annual International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC 2018
PublisherInstitute of Electrical and Electronics Engineers Inc.
ISBN (Electronic)9781538660096
DOIs
StatePublished - 18 Dec 2018
Event29th IEEE Annual International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC 2018 - Bologna, Italy
Duration: 9 Sep 201812 Sep 2018

Publication series

NameIEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC
Volume2018-September

Conference

Conference29th IEEE Annual International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC 2018
CountryItaly
CityBologna
Period9/09/1812/09/18

Keywords

  • Channel estimation
  • Least squares
  • Massive MIMO
  • Pilot contamination
  • Synchronization
  • Time-division duplex

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  • Cite this

    Li, W. H., Wu, J-Y., Hsu, C. K., & Wang, L-C. (2018). Least-Squares Pilot Sequence Design for TDD Massive MIMO Systems under Inter-Cell Timing Misalignment. In 2018 IEEE 29th Annual International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC 2018 [8580816] (IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC; Vol. 2018-September). Institute of Electrical and Electronics Engineers Inc.. https://doi.org/10.1109/PIMRC.2018.8580816