Low latency integrated point-to-multipoint and e-band point-to-point backhaul for mobile small cells

Wireless backhaul is one of the main challenges in small cell deployment. Current wireless backhaul systems have one or more limitations on capacity, link distance and supporting line-of-sight (LOS) links. In this paper, we propose a novel two-tier small-cell backhaul architecture which provides a future-proof, powerful, flexible and scalable solution by using aggregation nodes and integrating sub-6GHz point-to-multipoint (P2MP) and point-to-point E-band links. In the bottom tier of the proposed architecture, local small cells are connected to an aggregation node by P2MP and low-cost mega bits per second (Mbps) E-band links; in the top tier, aggregation nodes are inter-connected by LOS giga bits per second (Gbps) E-band links. PHY and higher layer protocols, which integrate the three different links into a comprehensive solution, are introduced. Designs of devices used in the architecture, which are being developed in CSIRO, are provided. Novel techniques that have been developed for achieving low-latency are detailed. Simulation results show that the backhaul latency can be as low as a few microseconds when only E-band backhaul links are involved.