Effective service delivery and group management in integrated terrestrial-HAP systems for multicast communications

Multicast service delivery can be easily guaranteed to users in disadvantaged areas by effectively integrating HAPs (High Altitude Platforms) into the terrestrial cellular system. HAPs are meant to be as unmanned aerial vehicles, airships or aircrafts, which remain relatively stationary in the stratosphere at short distance from Earth compared to satellites. In the scientific literature, there is evidence of the effectiveness of a UMTS (Universal Mobile Telecommunications Systems) system augmented by the presence of HAPs, which are equipped with UMTS payloads and play the role of additional base stations. This integrated terrestrial-space platform intrinsically fits the exigencies of rural and emergency scenarios, which are characterized by network resource scarcity, due to either geographical reasons (such as in rural areas) or to temporary resource over-utilization/reduction (due to emergency status). In this paper, the focus is on the delivery of Multimedia Broadcast/Multicast Services (MBMS) in the reference integrated architecture. Main objectives are designing resource allocation policies to manage multicast groups between space and terrestrial coverages, and analysing their feasibility and performances in terms of offered grade of service.