Radio Resource Management Considerations for 5G Millimeter Wave Backhaul and Access Networks

Millimeter-wave frequencies between 6 and 100 GHz provide orders of magnitude larger spectrum than current cellular allocations and allow usage of large numbers of antennas for exploiting beamforming and spatial multiplexing gains. In this article, we describe the main design concepts when integrating mmWave RANs into 5G systems, considering aspects such as spectrum, architecture, and backhauling/fronthauling. The corresponding RRM challenges, extended RRM functionalities for 5G mmWave RAN, and RRM splits are addressed. Finally, based on these discussions, a framework is proposed that allows joint backhaul and access operation for 5G mmWave RAN, which we envisage as one of the key innovative technologies in 5G. The proposed framework consists of a joint scheduling and resource allocation algorithm to improve resource utilization efficiency with low computational complexity and to fully exploit spatial multiplexing gain for fulfilling user demands.