A Novel Geometric Handover Model for Aerial 4G Networks with WiFi-based X2 Interface

Given the temporary nature of radio communications for mission critical scenarios, the existing dedicated public safety network lacks the flexibility of cutting edge technologies to leverage on packet data services. In this context, new challenges arise such as high-capacity demand and low-latency flexible backhaul connection for public safety users. In this paper, we consider a scenario in which 4G LTE radio coverage is provisioned by aerial eNodeBs installed on low-altitude platforms raised in the sky and interconnected through WiFi links. We focus our attention on the critical aspect of the Third Generation Partnership Project handover mechanism studying the handover performance using a X2 interfaces over WiFi links. We develop a novel eometric model of the handover in the context of public safety communications but extensible also to other contexts. Relying on such a model, the handover failure probability is computed taking into account the different handover phases. The coverage area of an aerial eNodeB is studied using a suitable air-to-ground propagation model, while the average handover duration is computed taking into account the delay introduced by the WiFi communication dynamics.