Joint routing and resource allocation for wireless self-backhaul in an indoor ultra-dense network

To cope with the exponential growth in mobile data traffic, substantially denser deployments of base stations are anticipated in the future. The feasibility of such dense deployments is predicated on the existence of a high-data-rate transport network. Wireless self-backhaul, where the same radio spectrum is used for both access and transport, is an attractive solution due to its potentials of substantially reducing the deployment cost. With the limited range of radio signals in the high frequency bands where some future wireless systems are likely to be deployed, a wireless route of multiple hops may need to be established between each access node and an aggregation node where data traffic originates and terminates. To maximize the throughput of each of these routes, the route selection process should take into account the mutual interference among wireless links. In this paper, we investigate the feasibility of the wireless self-backhaul solution for an ultra-dense wireless network in an indoor environment with inter-node distance in the order of ten meters or less. A joint design approach is adopted here where the routes for all active access nodes, along with the radio resources associated with each link of these routes, are simultaneously selected. Simulation results based on a ray-tracing indoor channel model indicate that multi-hop self-backhaul is a viable backhaul solution. However, compared to wired backhaul, self-backhaul incurs significant limitation on total system throughput, especially at high load.