Region-based Geocast routing protocols for VANETs: Summary, evaluation methods and simulation models

Vehicular Ad hoc Networks (VANETs) is a technology to support communication among vehicles or between vehicles and infrastructure in order to exchange traffic information and avoid accidents. Many applications in VANETs need to transmit messages to vehicles within a specific geographic region. This behaviour is called Geocast. Several Geocast routing protocols have been proposed for VANETs. In this paper, some important and representative Geocast routing protocols are summarized and theoretically compared. In order to evaluate the performance of these protocols, the evaluation methods are also defined, which include both the Packet Delivery Ratio (PDR) and the Packet Delivery Time (PDT). Additionally, some important and new models, such as the influences of city lights, and the distance between buildings potentially acting as free line of sight obstacles, are proposed to create a more realistic city environment for Geocast routing simulation.