Hybrid Beamforming with G2+1+1 Transmission Scheme and Modified SIC Design for Milimeter Wave Channel

Abstract

The use of massive multiple input multiple output (MIMO) has been considered as a key enabler to achieve the 5G requirements [1]. With the large array of antennas, the beamformers’ uses have become very attractive, specially when the energy is concentrated in a specific direction. However, implementing large arrays becomes prohibitive since the digital-analog converters (DAC) are power hungry devices connected to every radio frequency (RF) chain. So to deal with this bottleneck, the number of RF chains is reduced by using the hybrid beamforming (HB) solution whose implementation enables us to use fewer RF chains than the digital solution while maintaining a high number of antennas. In this work, we propose to extend a diversity-multiplexing transmission scheme called as G2+1+1 for massive MIMO systems in millimeter wave (mmWave) channel. To implement such scheme, we design a Hybrid Beamforming at the base station and a nonlinear decoder at the receiver. Compared with the traditional G2+1+1, our transmission scheme combines diversity, multiplexing and array gains into one unique device. We show in our simulations that our scheme outperforms in terms of bit-error rate (BER) other solutions that only exploit massive MIMO multiplexing gain. Such results show that the proposed solution is very attractive to increase the system reliability and provides enhanced robustness in low and high SNR scenarios.