Subspace-Based Semi-Blind Channel Estimation for User-Centric Cell-Free Massive MIMO Systems

Bowen Zhong*, Xu Zhu, Eng Gee Lim

*Corresponding author for this work

Research output: Chapter in Book or Report/Conference proceedingConference Proceedingpeer-review

Abstract

Recently, the user-centric (UC) cell-free (CF) massive multiple-input multiple-output (MIMO) system has emerged as one of the most promising enablers for future wireless networks. However, with the increase of the number of user equipments (UEs) in the network, pilot reuse for channel estimation causes interference, referred to as pilot contamination. In this paper, a subspace-based semi-blind channel estimation scheme is proposed for UC CF massive MIMO systems. By exploiting the uplink data signal received at each access point (AP), eigenvalue-decomposition (EVD) is employed on the covariance matrix of received signal to obtain the signal subspace. Based on the channel gains and pilot assignment results for each UE, a subspace selection scheme is developed to separate target signal from interference in subspace, which is followed by subspace projection to mitigate the pilot contamination. Simulations results verify the effectiveness of the proposed scheme in improving the uplink channel estimation accuracy of UC CF systems even without the prior knowledge of channel covariance matrix.

Original languageEnglish
Title of host publication2024 IEEE 99th Vehicular Technology Conference, VTC2024-Spring 2024 - Proceedings
PublisherInstitute of Electrical and Electronics Engineers Inc.
ISBN (Electronic)9798350387414
DOIs
Publication statusPublished - 2024
Event99th IEEE Vehicular Technology Conference, VTC2024-Spring 2024 - Singapore, Singapore
Duration: 24 Jun 202427 Jun 2024

Publication series

NameIEEE Vehicular Technology Conference
ISSN (Print)1550-2252

Conference

Conference99th IEEE Vehicular Technology Conference, VTC2024-Spring 2024
Country/TerritorySingapore
CitySingapore
Period24/06/2427/06/24

Keywords

  • Cell-free massive MIMO
  • EVD
  • Pilot contamination
  • Semi-blind channel estimation

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