Performance of ZF and CB Precoding Techniques for Large-Scale MU-MIMO System
Jagtar Singh1, Deepak Kedia2 

1Jagtar Singh, Research Scholar, Department of Electronics and Communication Engineering, Guru Jambheshwar University of Science & Technology, Hisar, Haryana,
2Dr. Deepak Kedia, Professor, Department of Electronics and Communication Engineering, Guru Jambheshwar University of Science & Technology, Hisar, Haryana,

Manuscript received on 12 March 2019 | Revised Manuscript received on 16 March 2019 | Manuscript published on 30 July 2019 | PP: 5529-5536 | Volume-8 Issue-2, July 2019 | Retrieval Number: B3283078219/19©BEIESP | DOI: 10.35940/ijrte.B3283.078219
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© The Authors. Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP). This is an open access article under the CC-BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Abstract: Large Scale Multi User-MIMO (MU-MIMO) is a key technology with reference to 5G to achieve higher spectrum as well as energy efficiency. The new technology refers to the use of a large number of antennas at the base station serving many user terminals in the same time and frequency resource allowing the channel vectors nearly orthogonal as a result, there is a reduction in inter-user interference and users may be served with the significant data rate. The linear precoding techniques play a vital role in the reduction of interference among users and cells. In this paper, we have derived, analyzed and compared two important precoding techniques i.e. Zero-forcing (ZF) and Conjugate beamforming (CB) for large-scale multiuser-MIMO. We analyze these precoding techniques with respect to spectral efficiency and downlink power with imperfect channel state information (CSI) as well as with perfect CSI. It is shown that ZF performs better as compared to CB precoding for achieving higher spectral efficiency and requires lower downlink power. CB outperforms the ZF in terms of downlink transmit power when there is a requirement to achieve low spectral efficiency and also for cell- edge users, hence energy efficient in these cases. It is shown from simulation results that ZF precoding is the better choice for attaining higher spectral and energy efficiency for a large scale multiuser-MIMO communication system.
Index Terms: MU-MIO, Large Scale MU-MIMO, Precoding, Spectral Efficiency, Energy Efficiency, Downlink Power, Conjugate Beamforming, Zero Forcing

Scope of the Article: Performance Evaluation of Networks