Wireless Backhaul in Small Cell Networks: Modelling and Analysis

Consumer demand for data traffic has increased tremendously, and small cell networks are increasingly being considered as one of the key technology drivers to cope with the so-called mobile date tsunami. The deployment of small cell networks within the conventional macro cellular networks creates a significant amount of heterogeneity compared to conventional cellular networks, and in this context, backhaul- related issues have important implications in terms of both cost and system performance. In this paper, we consider a hierarchical network structure to model the wireless backhaul in small cell networks. We derive the total expected delay by taking into account retransmission over the wireless links, as well as the backhaul delay in the wireless backhaul link. As for the total expected deployment cost, we take into account infrastructure cost as well as the construction cost of laying backhaul links. Specifically, we are able to characterize the behavior of delay and deployment cost using our simple and tractable model. In summary, our analysis provides a fundamental understanding of the wireless backhaul and its effect on the deployment cost and the system performance in heterogeneous cellular networks.