Load-Balanced Routing for Hybrid Fiber/Wireless Backhaul Networks

Dense deployment of small-cell base stations (BSs) requires a backhaul network to efficiently connect the BSs to the core network. In this paper, we focus on a hybrid backhaul architecture where some BSs connect with fiber to the core network and provide mmWave backhaul connections for the rest of the BSs. This architecture brings new challenges, e.g., how to prevent a large amount of traffic from becoming concentrated at certain egress BSs, thereby hurting overall backhaul performance. In this paper, we propose a load-balanced routing algorithm to address this challenge. We first define the concept of load balance factor (LBF) and address the challenge through a hill climbing procedure that attempts to minimize LBF. Results show that the proposed algorithm can distribute the dynamic traffic loads from different BSs nearly optimally among fiber-connected BSs for the simulated settings. We also present a variation of the algorithm that permits trade-offs between routing path length and load balance factor.