Ultra-Dense Networks for 5G and Beyond

4Inband Full‐duplex Self‐backhauling in Ultra‐dense Networks

Dani Korpi¹, Taneli Riihonen² and Mikko Valkama²

¹Nokia Bell Labs, Espoo, Finland

²Laboratory of Electronics and Communications Engineering, Tampere University of Technology, Finland

4.1 Introduction

Traditionally, the backhauling of data in cellular networks has been handled by connecting the base station (BS) or access node (AN) to a core network via a physical cable. This ensures high data rates for the backhaul link, but requires the installation of cables, which entails a high cost. This is an especially significant issue in the ultra‐dense networks, where the number of ANs is too high for a physical backhaul link to be commercially feasible. To this end, the prospect of wireless backhaul connections has been brought up. It would mean that no cables were required, making the corresponding cellular networks more easily scalable to higher densities.

In the current systems, the basic principle behind the wireless backhaul links has been to ensure line‐of‐sight (LOS) and to use a center frequency different to that utilized in the actual access link between the AN and the user equipments (UEs). Although some of the benefits of wireless connectivity can still be obtained with such an approach, careful planning and additional spectral resources are required. Together, these aspects reduce the cost‐efficiency of the wireless backhauling solution, hindering the commercial feasibility of utilizing such an approach in very ...