Impact of wireless NLOS backhaul design on small-cells deployment and end-user experience

This paper presents a study on the performance of a dense urban small-cell densification, where the limitations and design challenges related to the wireless small-cell backhaul are considered. While most evaluations of the small-cell capability to increase the end-user experience do simply assume ideal backhaul, here a wireless and capacity-limited backhaul is introduced. The design methodology, that is analyzed and illustrated in the paper, addresses the joint small-cell and backhaul wireless deployment thanks to new techniques designed in EU-funded European projects. An advanced system simulation tool embeds 3D ray-tracing and computes both the user-interface and wireless backhaul layers, where limitations on backhaul links impact the end-user throughput. Different backhaul design options are compared, based on the user downlink and uplink throughputs, on the hub and small-cell loads, and on the ElectroMagnetic Field (EMF) exposure. The paper also illustrates how an automated backhaul design can achieve improved performance for both the end-user and operator point of views.