TY - JOUR
T1 - Superimposed Pilot Optimization Design and Channel Estimation for Multiuser Massive MIMO Systems
AU - Jing, Xiaorong
AU - Li, Mengwan
AU - Liu, Hongqing
AU - Li, Shaoqian
AU - Pan, Gaofeng
N1 - Publisher Copyright:
© 1967-2012 IEEE.
PY - 2018/12
Y1 - 2018/12
N2 - For massive multiuser multiple input multiple output (MIMO) (MU-MIMO) systems, pilot contamination (PC) and data interference (DI) are two main factors that affect the accuracy of the superimposed pilot (SP) based channel estimation, provided that the channel coherence time is less than the total number of users. In this paper, to tackle the effect of the PC, we propose a block-diagonal Grassmannian line packing (GLP) approach, in which the specific sequences for different cells are first designed based on the GLP, and then are block-diagonally extended to form the SP matrices for the users in different cells. To also alleviate the effect of DI on the channel estimation, with the designed SP matrices, an iterative channel estimation (ICE) method based on Tikhonov regularization is presented. The impact that the proposed ICE method has on the signal-To-interference-plus-noise ratio with matched filtering receiver is theoretically analyzed. Moreover, the optimal power allocation factor to the SP by maximizing the spectral efficiency (SE) of the target cell is also derived. Numerical results show that the proposed ICE method with the designed SP matrices effectively mitigates the effects of the PC and DI, and hence, improves the accuracy of channel estimation and further the SE of the massive MU-MIMO systems.
AB - For massive multiuser multiple input multiple output (MIMO) (MU-MIMO) systems, pilot contamination (PC) and data interference (DI) are two main factors that affect the accuracy of the superimposed pilot (SP) based channel estimation, provided that the channel coherence time is less than the total number of users. In this paper, to tackle the effect of the PC, we propose a block-diagonal Grassmannian line packing (GLP) approach, in which the specific sequences for different cells are first designed based on the GLP, and then are block-diagonally extended to form the SP matrices for the users in different cells. To also alleviate the effect of DI on the channel estimation, with the designed SP matrices, an iterative channel estimation (ICE) method based on Tikhonov regularization is presented. The impact that the proposed ICE method has on the signal-To-interference-plus-noise ratio with matched filtering receiver is theoretically analyzed. Moreover, the optimal power allocation factor to the SP by maximizing the spectral efficiency (SE) of the target cell is also derived. Numerical results show that the proposed ICE method with the designed SP matrices effectively mitigates the effects of the PC and DI, and hence, improves the accuracy of channel estimation and further the SE of the massive MU-MIMO systems.
KW - Grassmannian line packing (GLP)
KW - Massive multiuser multiple input multiple output (MU-MIMO)
KW - Tikhonov regularization (TR)
KW - iterative channel estimation (ICE)
KW - spectral efficiency (SE)
KW - superimposed pilot (SP)
UR - http://www.scopus.com/inward/record.url?scp=85054610762&partnerID=8YFLogxK
U2 - 10.1109/TVT.2018.2875480
DO - 10.1109/TVT.2018.2875480
M3 - Article
AN - SCOPUS:85054610762
SN - 0018-9545
VL - 67
SP - 11818
EP - 11832
JO - IEEE Transactions on Vehicular Technology
JF - IEEE Transactions on Vehicular Technology
IS - 12
M1 - 8489887
ER -