Achieving Fully-Digital Performance by Hybrid Analog/Digital Beamforming in Wide-Band Massive-Mimo Systems

In this paper, we study the realization of any given fully-digital precoder (FDP) by hybrid analog/digital precoding (HADP) in wide-band mmWave systems. We first formulate the massive-MIMO OFDM-based HADP system design and then, introduce the notion of perfect reconstruction at sampling point (PRSP) for FDP realization. Furthermore, the minimum number of required RF chains and its trade-off with the bandwidth of the transmitted signal is discussed. Next, we present a novel FDP realization with two RF chains. Finally, simulation results are presented showing the superiority of the proposed hybrid design to recently published works.