Transmit Beamforming Strategies with Iterative Equalization for Hybrid mmW Systems

摘要

The aim of this manuscript is to compare the performance of two transmit beamforming approaches with an iterative equalizer for millimeter wave (mmW) systems. At the transmitter, we assume two hybrid beamforming: a sparse beamforming approach recently proposed and fixed random beamforming which the coefficients are computed independently of the instantaneous channel realization. At the receiver, we consider a hybrid iterative block space-time structure to efficiently separate the spatial streams. We consider that both the transmitter and the received are equipped with a large antenna array and the number of radio frequency (RF) chains is lower that the number of antennas. The hardware limitations impose several constraints in the analog domain that are considered when the transmit beamforming/precoder is generated. Our performance results have shown that the performance of the sparse precoder is better for low signal-to-noise ratio (SNR) regime while random precoder outperforms sparse based one for medium to high SNR regime.