Performance Improvement for Multi-User Millimeter-Wave Massive MIMO Systems

• Published in: IEEE access Vol. 8; pp. 87735 - 87748
• Main Authors: Carrera, Diego Fernando, Vargas-Rosales, Cesar, Villalpando-Hernandez, Rafaela, Galaviz-Aguilar, Jose Alejandro
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 2020; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: 5G NR; antenna array; Antenna arrays; Array signal processing; Beamforming; Channel estimation; Hardware; Interference; massive MIMO; Millimeter waves; millimeter-wave; MIMO (control systems); MIMO communication; Radio frequency; Receivers
• ISSN: 2169-3536; 2169-3536
• DOI: 10.1109/ACCESS.2020.2994176

In this paper, we study the problem of optimizing the performance of multi-user millimeter-wave (mmWave) communications in three steps. The first one is given by the use of a new pilot mapping to reduce the inter-user interference effect and to perform more accurate channel estimation. In the second step, we designed a hybrid receiver that, based on the accuracy of the channel state information, chooses between the minimum mean square error (MMSE) and the multi-user regularized zero-forcing beamforming (RZFBF) receivers, to combine/precode the massive multiple-input multiple-output (MIMO) signal. In the third step, we propose to improve the beam direction with a slight change in the azimuth angle during the uplink communications to increase the multi-user efficiency and reduce inter-user interference. Numerical results show the performance increase using the proposed solutions in terms of the spectral efficiency by comparing the MMSE, RZFBF, and hybrid receivers.