DVB-RCS Spotbeam Handover Using Residence Time Estimations in Vehicular Satellite Networks

Satellite systems are viewed as viable access providers for the growing collective user communities on board aircrafts, high speed trains, and maritime vessels that expect communication services while outside the coverage of terrestrial communication infrastructure. This paper analyses handover management in vehicular satellite networks with a particular emphasis on mobility adaptations required by the DVB-RCS standard. The proposed strategy relies on a distributed position- based mechanism for spotbeam handover detection and a centralised decision. An accurate GPS-derived mobility pattern description is periodically conveyed via SYNC bursts to the NCC, which uses estimations of the residual residence time within the current spotbeam to assign priorities to handover requests. The NCC implements a threshold-based queuing mechanism to refine resource assignment and minimise handover failures. Through an accurate NS-2 modelling of existing DVB-RCS signalling mechanisms, we show that our handover scheme outperforms position-based solutions operating a first-come-first-served policy under different congestion levels and channel conditions. Results are achieved at no change to the signalling messages that are already laid out in the DVB-RCS specification.