Small LTE Base Stations Deployment in Vehicle-to-Road-Infrastructure Communications

In this work we study the application of LTE small base stations on roads characterized by high traffic density, as for example parts of national highways in the proximity of important cities. Small BSs respond to the necessity of obtaining excellent performance without high capital investments and with easy installment (e.g. on the already existing lattices for traffic signalling) and fast auto-configuration. It should be noted that cellular networks, whose infrastructure is already widely deployed, have been proposed several times for vehicular applications especially in the third generation radio network (UMTS). Nevertheless in LTE and in future next generation radio network, heterogeneous and scaled radio stations, covering overlapping areas of different sizes, will be one of the keys for an optimal, from a technical point of view, and cost effective usage of the bandwidth. So next generation LTE small BSs, specifically designed and dedicated only to the road coverage by means of small cells, could constitute a valid, inexpensive option at least for road scenarios characterized by high traffic and user densities. In this work, we investigate three fundamental features for the physical layer of V2I in LTE small cells: the topological layout, including the role of the antenna directivity function, the scheduling strategies for V2V connection performance and the impact of imperfect channel estimation in fast time varying scenarios.