Master Thesis

Research in the field of Intelligent Transport Systems (ITS) is emerging, motivated by the need for improved road safety and environmental concerns. In Europe, many traffic fatalities occur each year and the transportation industry is one of the largest emitting industry of greenhouse gases. These problems can be mitigated by the use of vehicular networks, safety applications can directly affect road safety and indirectly improve traffic flow resulting in less emission. Information dissemination in pure Vehicular Ad hoc NETworks (VANET) becomes problematic when the network is sparse. This is certainly the case in the early years of market introduction, because of the low market penetration. Moreover, in rural areas or during night-time the vehicular network can become sparse due to low traffic density. Sparse vehicular networks become fragmented, resulting in disconnected clusters of vehicles due to the limited communication range of Car-to-Car (C2C) technology. Therefore, information dissemination beyond these clusters is impossible or leads to massive delays by using techniques such as Store-Carry-Forward. This thesis proposes the addition of Car-to-Satellite (C2S) communication to solve this issue. The large coverage of C2S complements C2C, this way the satellite can be used to bridge communication between clusters, hence information dissemination can be improved. The impact of supplementing C2C with C2S is quantified by simulating a realistic real-world scenario. A rural area in the southern part of Germany has been simulated, by using OpenStreetMap and real traffic data from official traffic census. The simulation is executed using SUMO, for traffic simulation, in conjunction with ns-3, for simulating information dissemination. The information dissemination is evaluated with respect to the in-time reception of safety-related information, by means of a Road Hazard Warning (RHW) application. This application implies that a vehicle driving through a rural area detects a dangerous situation on the road and sends out a RHW to all vehicles in the vicinity. The RHW is kept alive within a certain area, called the area of validity, for some period of time, which is called the time of validity or Time to Live (TTL). The results show that information dissemination can be significantly improved through a limited number of C2C vehicles which are additionally equipped with C2S. In fact, if the results are related to the prediction of C2C market introduction, it is shown that adding C2S can have the same effect as pushing forward the market introduction of C2C significantly by up to 12 years. Hence, combining C2C with C2S can have great impact on the future of cooperative ITS.