Improving Semi-Blind Uplink Interference Suppression on Multicell Massive MIMO Systems: A Beamspace Approach

Chang-Jun AHN

IEICE TRANSACTIONS on Communications   Vol.E102-B    No.8    pp.1503-1511
Publication Date: 2019/08/01
Publicized: 2019/02/20
Online ISSN: 1745-1345
DOI: 10.1587/transcom.2018TTP0005
Type of Manuscript: Special Section PAPER (Special Section on Technology Trials and Proof-of-Concept Activities for 5G and Beyond)
massive MIMO,  multicell,  pilot contamination,  adaptive array,  constant modulus algorithm,  channel estimation,  decision feedback,  beamspace,  

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This paper improves our previously proposed semi-blind uplink interference suppression scheme for multicell multiuser massive MIMO systems by incorporating the beamspace approach. The constant modulus algorithm (CMA), a known blind adaptive array scheme, can fully exploit the degree of freedom (DoF) offered by massive antenna arrays to suppress inter-user interference (IUI) and inter-cell interference (ICI). Unfortunately, CMA wastes a lot of the benefit of DoF for null-steering even when the number of incoming signal is fewer than that of receiving antenna elements. Our new proposal introduces the beamspace method which degenerates the number of array input for CMA from element-space to beamspace. It can control DoF expended for subsequent interference suppression by CMA. Optimizing the array beamforming gain and null-steering ability, can further improve the output signal-to-interference and noise power ratio (SINR). Computer simulation confirmed that our new proposal reduced the required number of data symbols by 34.6%. In addition, the 5th percentile SINR was also improved by 14.3dB.