BP-MR: Backpressure Routing for the Heterogeneous Multi-Radio Backhaul of Small Cells

Dense deployments of small cells (SC) will help satisfying the explosive growth of mobile data usage. However the deployment of such networks implies several challenges where point-to-point (PTP) and point-to-multipoint (PMP) wirelesss technologies will be combined forming multipoint-to-multipoint (MP2MP) wireless mesh backhauls. In this initial work produced within the SANSA project, we propose Backpressure for Multi-Radio (BP-MR), a distributed dynamic routing and load balancing protocol designed for MP2MP wireless mesh bakchauls where each node may embed a different number of multi-technology wireless interfaces.

In BP-MR, each SC maintains a data queue per interface and carries out the routing process in two stages. The first one distributes ingress packets with the goal of reducing the Head of Line (HoL) blocking effect in a multi-radio SC. The second stage determines the actual outgoing interface and the next-hop for each packet  at the head of the queues. Simulation results show improvements in throughput and latency with respect to other state-of-the-art approaches as a consequence of an improved wireless link usage efficiency. Future work within SANSA project will consider the enhancement of this protocol in the proposed LTE hybrid backhaul network.