Millimeter Wave Communications over Relay Networks

Abstract

Relays are expected be an important factor in the implementation of millimeter wave (mmWave) based cellular networks due to the limited coverage of mmWave communications. Adding a single or multiple relays in the link between
two nodes is an inevitable step towards high capacity wireless access and/or backhaul links. In this paper we suggest employing two-hop multiple relay networks as a solution to link two points using mmWave frequencies. Hybrid (Analog and Digital) precoding is used at the two terminal nodes with analog beamformers/ combiners at the relays. The proposed design algorithm requires no channel information with relatively limited training overhead. The performance of the system is examined under different channel and system layouts. The results highlight the positive impact of employing relays in mmWave link as well as the effect of array size on the overall system performance.

Index Terms—Millimeter wave, Hybrid beamforming, Relay Networks, Channel Sounding, 5G.