Joint link-level and network-level reconfiguration for urban mmWave wireless backhaul networks

Abstract

Due to the rapid densification of small cells in 5G and beyond cellular networks, deploying wired high-bandwidth connections to every small cell base station (BS) is difficult, particularly in older metropolitan areas where infrastructure for fiber deployment is lacking. For this reason, mmWave wireless backhaul has been proposed as a cost-effective and flexible alternative that has the potential to support the high data rates needed to accommodate backhaul traffic demands. To address the robustness of such networks, we investigate a novel relay-assisted backhaul architecture, where a number of small-cell BSs and relays are deployed, e.g. on the lampposts of urban streets. In this scenario, the interconnected logical links constitute a mesh network, which offers opportunities for both link-level and network-level reconfiguration to overcome blockages and/or node failures. We present two joint link-network level reconfiguration schemes for recovery after exceptional events. One prioritizes relay path (link-level) reconfiguration and uses alternate network-level paths only if necessary. The other splits traffic on both reconfigured logical links and backup network paths to improve throughput. Through simulation, the reconfiguration schemes are shown to not only provide near-optimal backhaul survivability but to also maintain high network throughput across a range of scenarios for urban mmWave backhaul networks. The schemes are also validated to significantly outperform existing purely link-level and purely network-level reconfiguration schemes.