Performance evaluation of receiver based routing protocols for infotainment services in vanets

Intelligent Co-operative Systems are the next big challenge in automotive electronics and Intelligent Transportation Systems (ITS). Intelligent Co-operative Systems, that are based on Inter-Vehicle Communication (IVC), hold the promise of great improvements both in the efficiency of the transport systems and in the safety of all road users. Intersection collision avoidance, lane keeping, and motion control are just a few of safety applications emerging after the development of IVC systems. Intelligent Co-operative Systems also offer traffic efficiency applications, such as automated highways, toll systems, group motion control, route optimization, adaptive acceleration and speed limiters where vehicles individually or co-operatively regulate their motion, adjusting their velocity and heading in response to others nearby and to the changes in the environment.Traffic safety and efficiency applications require the delivery of the packets generated by a vehicle to nearby vehicles in a timely manner. Routing protocols used in wired networks are not applicable for these types of networks. Thus, geographic routing protocols which use position information are required to perform routing in such networks.Recent advances in IVC systems enable the use of these systems for infotainment services besides traffic efficiency and safety applications. However, routing requirements of such services are different from the requirements of traffic efficiency and safety applications. Thus, in order to provide infotainment services over IVC systems, geographical routing protocols must be modified.In this thesis, we examined the existing geographical routing protocols which are categorized in two classes as sender-based and receiver-based. Although the existing research and standards mostly use the sender-based approach, it is also stated that the receiver-based approach must be carefully examined. In this thesis, we surveyed existing receiver-based routing protocols and examined the applicibility of these protocols for the infotainment services. After a careful examination, we chose three receiver-based protocols; Contention Based Forwarding (CBF), Location Aided Routing (LAR), and Receiver-based Opportunistic Forwarding (ROF). These protocols are implemented in a simulation environment and then their performance are compared with sender-based Greedy Forwarding (GF) protocol.During our simulations, it is clearly seen that receiver-based protocols perform better than the GF protocol in both city and highway scenarios. Among the receiver-based protocols, LAR protocol has the highest performance. During our simulations, we observed two anomalies about the receiver-based protocols. First, they have higher end-to-end packet delays compared to GF protocol. Second, to the contrary of the expectations, receiver-based protocols generate higher number of extra packets than the GF protocol. The reason for these two anomalies stems from the back-off timer mechanisms, which are used for relaying packets. Development of new mechanism for receiver-based protocols will improve the performance of receiver-based protocols.