Wireless Transport for Centralised Mobile Network Architectures

The objectives of this work aim to understand the role of wireless transport systems in future mobile network architectures. Mobile network deployments to date have been heavily dependent on point-to-point microwave radio links to connect geographically distributed cell sites into the network. New network architectures promise improved efficiency and cost reduction through centralisation of base station baseband functionality away from the traditional cell site. The extent to which wireless transport can fulfil the higher performance requirements of the resulting fronthaul connectivity is explored in this work. A high resolution 3D environmental model is developed to facilitate the analysis of high frequency, line-of-sight wireless links across UK towns and cities. The model is used to determine the statistical properties of cell site infrastructure both in terms of physical environment and the probability of achieving line-of-sight radio conditions. These statistical results allow for a more detailed deployment analysis of smaller area to be reliably scaled to equivalent environments. The possibility of routing high capacity wireless links between newly built street level cell sites and existing fibre locations using the discovered line-of-sight propagation paths is subsequently analysed. The performance requirements of emerging fronthaul transport interfaces and the capabilities of new mmWave and sub-THz spectrum bands (71 GHz - 174.8 GHz) are used as routing criteria in the geo-spatial deployment model in order to identify which combination of fronthaul interface and spectrum band could maximise the potential of wireless transport. Incremental results in this work have demonstrated that the concept of wireless fronthaul networks are not only theoretically achievable but experimentally proven and practically realisable. The conclusions of this work have determined the optimum combinations of fronthaul interface and wireless spectrum which should be pursued in order to maximise the opportunity of wireless transport to support future centralised deployment architectures.