An Interference-Robust Channel Estimation Method for Transparent MU-MIMO Transmission in LTE-Advanced System

Won-Jun HWANG  Jun-Hee JANG  Seong-Woo AHN  Hyung-Jin CHOI  

IEICE TRANSACTIONS on Communications   Vol.E97-B   No.7   pp.1412-1421
Publication Date: 2014/07/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E97.B.1412
Type of Manuscript: PAPER
Category: Wireless Communication Technologies
channel estimation,  interference detection,  LTE-Advanced,  MU-MIMO,  SIC,  

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In LTE (Long Term Evolution)-Advanced system, a transparent MU-MIMO (Multi-User Multiple-Input Multiple Output) scheduling is basically considered, so the performance degradation in channel estimation may occur due to the unpredictable interference from co-scheduled layers. In order to detect and mitigate the interference, traditional binary hypothesis testing based interference detection method and iterative channel estimation method can be applied. However, there are two major problems. First, the binary hypothesis testing based interference detection is not suitable solution for LTE-Advanced system which has four dynamically changing interference hypotheses. Second, the conventional iterative operation does not guarantee sufficient performance gain with limited iteration time due to the estimation error in initial estimation stage. To overcome these problems, we introduce an enhanced iterative channel estimation method which considers simple matrix operation-based partial interference estimation. Based on the outcomes of the partial interference estimation, we can not only detect interference layers individually, but also partially eliminate the interference in initial channel estimation stage. Consequently, the proposed method can effectively mitigate the interference adaptively to the dynamically changing interference condition.