mw-HierBack: A Cost-Effective and Robust Millimeter Wave Hierarchical Backhaul Solution for HetNets

Dense deployments of small cells in heterogeneous networks (HetNets) massively increase spectral efficiency and capacity. Since ubiquitous fiber availability is prohibitively expensive, wireless backhaul technique via millimeter wave (mmWave) is regarded as a practical solution. Additionally, mmWave with huge under-utilized bandwidth is able to provide multi-Gbps data rate comparable to fiber lines. In this paper, we propose an mmWave hierarchical small cell base station backhauling (mw-HierBack) system to organize densely deployed base stations (BSs) in HetNet. A group of Super-BSs (S-BSs) are selected to minimize the resource cost on the gateways and to robustly relay backhaul traffic of the remaining BSs to the core network against any blockage or link failure. Under this network structure, we present a path protection strategy to balance backhaul traffic among S-BSs and to minimize the fluctuations incurred by rerouting. The simulation results show our solution can efficiently scale with the growth of BSs and properly route the backhaul traffic without overloading any one of the S-BSs.