Non-Orthogonal Pilot Analysis for Single-Cell Massive MIMO Circumstances

Pengxiang LI  Yuehong GAO  Zhidu LI  Hongwen YANG  

IEICE TRANSACTIONS on Communications   Vol.E102-B   No.4   pp.901-912
Publication Date: 2019/04/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.2017EBP3459
Type of Manuscript: PAPER
Category: Wireless Communication Technologies
non-orthogonal pilots,  single-cell massive MIMO,  normalized channel estimation error,  achievable uplink capacity,  

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This paper analyzes the performance of single-cell massive multiple-input multiple-output (MIMO) systems with non-orthogonal pilots. Specifically, closed-form expressions of the normalized channel estimation error and achievable uplink capacity are derived for both least squares (LS) and minimum mean square error (MMSE) estimation. Then a pilot reconstruction scheme based on orthogonal Procrustes principle (OPP) is provided to reduce the total normalized mean square error (NMSE) of channel estimations. With these reconstructed pilots, a two-step pilot assignment method is formulated by considering the correlation coefficient among pilots to reduce the maximum NMSE. Based on this assignment method, a step-by-step pilot power allocation scheme is further proposed to improve the average uplink signal-to-interference and noise ratio (SINR). At last, simulation results demonstrate the superiority of the proposed approaches.