TY - GEN
T1 - Subspace-Based Semi-Blind Channel Estimation for User-Centric Cell-Free Massive MIMO Systems
AU - Zhong, Bowen
AU - Zhu, Xu
AU - Lim, Eng Gee
N1 - Publisher Copyright:
© 2024 IEEE.
PY - 2024
Y1 - 2024
N2 - 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.
AB - 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.
KW - Cell-free massive MIMO
KW - EVD
KW - Pilot contamination
KW - Semi-blind channel estimation
UR - http://www.scopus.com/inward/record.url?scp=85206159842&partnerID=8YFLogxK
U2 - 10.1109/VTC2024-Spring62846.2024.10683682
DO - 10.1109/VTC2024-Spring62846.2024.10683682
M3 - Conference Proceeding
AN - SCOPUS:85206159842
T3 - IEEE Vehicular Technology Conference
BT - 2024 IEEE 99th Vehicular Technology Conference, VTC2024-Spring 2024 - Proceedings
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 99th IEEE Vehicular Technology Conference, VTC2024-Spring 2024
Y2 - 24 June 2024 through 27 June 2024
ER -