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Hybrid beamforming in uplink massive MIMO systems in the presence of blockers

Xinlin Zhang (Institutionen för signaler och system, Signalbehandling) ; M. Coldrey ; Thomas Eriksson (Institutionen för signaler och system, Kommunikationssystem) ; Mats Viberg (Institutionen för signaler och system, Signalbehandling)
ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings (1520-6149). p. 6503-6507. (2017)
[Konferensbidrag, refereegranskat]

Hybrid beamforming (HBF) is a potential solution to reduce the baseband hardware cost in massive multiple-input multiple-output (MIMO) systems that has drawn considerable attention recently. In this paper, we consider the uplink of a multiuser massive MIMO system in the presence of blockers. Such blockers, which arise from, for example, users served by other non-cooperative base stations (BSs), can limit the system performance if not handled properly. We propose a HBF scheme that can remove the impact of blockers, while preserving signals from intended users. Specifically, in our two-step receive beamforming scheme, the analog beamformer (ABF) is designed based on channel covariance matrices to minimize the powers of blockers, while the digital beamformer (DBF) deals with inter-user interference. We propose an iterative algorithm that efficiently gives a good sub-optimal solution to the NP-hard problem in the ABF design. Moreover, we consider a more complete BS architecture by incorporating automatic gain control (AGC) and analog-to-digital converter (ADC). As we show in the simulations, for a system with full-precision ADCs, our scheme approaches the sum rate of an ideal fully-digital system. Interestingly, for a system with low-resolution ADCs, our HBF scheme can even outperform a fully-digital system.



Denna post skapades 2017-07-28.
CPL Pubid: 250842

 

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Institutioner (Chalmers)

Institutionen för signaler och system, Signalbehandling (1900-2017)
Institutionen för signaler och system, Kommunikationssystem (1900-2017)

Ämnesområden

Signalbehandling

Chalmers infrastruktur