09-10-2012, 04:09 PM
Vehicular ad hoc network (VANET)
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INTRODUCTION
OVERVIEW
Vehicular ad hoc network (VANET), a subclass of mobile ad hoc networks (MANETS), is a promising approach for future intelligent transportation system (ITS). VANET is a promising approach for facilitating road safety, traffic management, and infotainment dissemination for drivers and passengers. These networks have no fixed infrastructure and instead rely on the vehicles themselves to provide network functionality.
VANETS consist of a set of vehicles equipped with onboard units (OBUs) and roadside units (RSUs) that communicate wirelessly. Nodes in the VANET have routing capabilities that facilitate multihop communication, especially designed for gathering and disseminating road safety and efficiency related information.
VANET routing protocols are responsible for the selection of paths from the source to the destination or destinations. This is a challenging task due to the intrinsic properties of VANETS, which include the variability of the network topology, high speed of the vehicles, network partitioning into clusters of vehicles or uneven network density, security and quality of service. Many VANET-specific routing solutions have been proposed in recent years. The key to all these protocols is to take advantage of additional information available in the vehicles, such as position, digital maps, or even planned routes.
To improve the performance of routing mechanisms, this project presents a solution named Geographic Source Routing with VISIONS: Vehicular Communication Improvement: Solution based on IMS Operational Nodes and Services (GSRV), which selects appropriate nodes for routing using the additional information provided by VISIONS. The VISIONS architecture involves OnBoard modules and Infrastructure modules. The OnBoard module includes GPS receiver, Vehicle Information Base (VIB), Location client, Terminal capabilities client, Multimedia Broadcast Multicast Service (MBMS) receiver and Prediction module. The Infrastructure module includes Location server, Terminal capabilities enabler, MBMS enabler, PHOTO adapter, Location DB, PHOTO DB and Capabilities DB. The VISIONS architecture collects and disseminates information using 3G technology.
OBJECTIVE
Goal of this project is to minimize the time delay and improve the packet delivery ratio in VANET by adaptive routing.
The existing protocol named Geographic Source Routing (GSR) has insufficient information so to ensure data connectivity, it selects its direct neighbors for routing, this results in more time delay. So, a solution is required to decrease the time delay and increase the packet delivery ratio.
The proposed solution named Geographic Source Routing with VISIONS (GSRV), selects appropriate nodes for routing using the additional information provided by VISIONS: Vehicular communication Improvement: Solution based on IMS Operational Nodes and Services, which collects and disseminates information using 3G technology. This decreases the time delay between the source and destination vehicles.
Thus, by using the proposed solution, the issues in VANET routing protocols like time delay has been reduced to improve the packet delivery ratio.
PROBLEM DEFINITION
LITERATURE REVIEW
Information Dissemination and Information Assurance in Vehicular Networks: A Survey
Vehicular networks aimed towards providing roadside services such as traffic alerts, estimated time to reach a destination, alternative routes, and in general improve the efficiency and safety on roads. Information exchange in such network occurs between vehicles (inter-vehicle communication) in an Ad Hoc manner and also with roadside base stations using so called dedicated short range communication links.
In vehicular networks, there will be limited access to an infrastructure network, supported by roadside base stations. Such access is limited in its nature for two reasons. First, the deployment of the infrastructure is expected to be slow and incremental leading to wide areas where there is no access to the infrastructure. Second, a complete deployment is expected to be sparse because of cost. The coverage provided by a roadside base station may be on the order of 200-300m while roadside base stations may be placed every km or so. Consequently, not all vehicles will be connected to the infrastructure at all times. To obtain access to safety or other types of information, it becomes necessary to rely on vehicle-to-vehicle communications.
vehicles A, B, C have access to a roadside infrastructure, which has limited coverage. These vehicles can obtain information from the roadside base station. However, vehicles D, E and F have no communications with the fixed infrastructure. For instance, vehicle F will have to rely upon information from vehicle E, which in turn has obtained information that has passed through vehicles A and D.