Hybrid Beamforming in Multiple User Massive Multiple Input Multiple Output 5G Communications System

In order to enhance the coverage and capacity of fifth generation cellular networks (5G) which is expected to be employed soon, massive multiple-input multiple-output (m-MIMO) and millimeter-wave (mm-Wave) technologies are being developed as solutions for these challenges. However, for large-scale antenna arrays that are anticipated in MIMO technology, the utilization of traditional fully-digital MIMO beam-forming methods is not practical, requiring one radio frequency (RF) chain per antenna element, leading to high cost and high power consumption. In order to reduce the RF chains number, hybrid analog and digital beam-forming has been studied and proposed. In this paper, a hybrid beam-forming structure is proposed in a massive MIMO communication channel with multiple users, each user having different number of data streams, with additive white Gaussian noise (AWGN) interfering with the signal throughout the path. The bit error rate (BER) of each transmitter for each user will be studied and compared under different circumstances for the proposed system VS different fully digital beam-forming methods, along with the spectral efficiency of the proposed hybrid beam-forming structure for each channel compared to fully digital, or in other words optimal beam-forming. Results of these comparisons will be shown and discussed to conclude the advantages and disadvantages of the proposed scheme.