Vehicu lar ad-hoc networks (VANETs) technology has emerged as an important research area over the last few years. Being ad-hoc in nature, VA NET is a type of networks that is created from the concept of establishing a network of cars for a specific need or situation. VA NETs have now been established as reliable networks that vehicles use for co mmunication purpose on highways or urban environments. Along with the benefits, there arise a large number of challenges in VANET such as provisioning of QoS, h igh connectivity and bandwidth and security to vehicle and individual privacy. This article presents state-of-the-art of VANET and discusses the related issues. Network architecture, signal modeling and propagation mechanis m, mobility modeling, routing protocols and network security are discussed in detail. Main findings of this paper are that an efficient and robust VANET is one wh ich satisfies all design parameters such as QoS, minimu m latency, low BER and high PDR. So me key research areas and challenges in VANET are presented at the end of the paper.

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Vehicular Ad-Hoc Networks (VANETs): An Overview and Challenges

The rise in the number of vehicles has led to a rapid increasing need for vehicle communication today. The emerging Vehicular Ad Hoc Network (VANET) is becoming more and more important, which can provide intelligent transportation application, comfort application and other services for people in vehicles. In order to provide stable routes and obtain good performance in VANET, proper routing protocols must be designed. At present, some kinds of routing protocol have been used in VANET. As one of the most important routing protocols used in Mobile Ad Hoc Networks (MANET), AODV routing protocol is also used in VANET, and is often evaluated with other kinds of protocols. However, due to the different characteristics of the two networks, AODV protocol suffers poor performances when it is applied in VANET directly. So in our improved AODV routing protocol in VANET, we make two steps optimization in route discovery and route selection process to improve the route stability and decrease overhead. Simulation results show that our proposed AODV protocol can get better performances in forms of link stability and packet delivery ratio.

An improved AODV routing protocol for VANETs

Vehicular ad hoc network (VANET) is an emerging wireless communications technology that is capable of enhancing driving safety and velocity by exchanging real-time transportation information. In VANETs, the carry-and-forward strategy has been adopted to overcome uneven distribution of vehicles. If the next vehicle located is in transmission range, then the vehicle forwards the packets; if not, then it carries the packets until meeting. The carry mostly occurs on sparsely populated road segments, with long carry distances having long end-to-end packet delays. Similarly, the dense condition could have long delays, due to queuing delays. The proposed intersection-based routing protocol finds a minimum delay routing path in various vehicle densities. Moreover, vehicles reroute each packet according to real-time road conditions in each intersection, and the packet routing at the intersections is dependent on the moving direction of the next vehicle. Finally, the simulation results show that the proposed Intersection-Based Routing (IBR) protocol has less end-to-end delay compared to vehicle-assisted data delivery (VADD) and greedy traffic aware routing protocol (GyTAR) protcols.

Intersection-Based Routing Protocol for VANETs

Vehicular Ad hoc Network (VANET) is a new communication paradigm that enables the communication between vehicles on the road network which falls in two categories: 1) Vehicle to Vehicle (V2V) and 2) Vehicle to Infrastructure (V2I). Various approaches of data dissemination in vehicular Network are used to inform vehicles about dynamic road traffic condition for achieving safe and efficient transportation system. Types of VANET applications and inherent characteristics such as unpredictable node density, fast movement of vehicles, constrained mobility make data dissemination quite challenging and general purpose ad hoc network routing protocols cannot work efficiently with it. In this paper, we propose a routing protocol IAODV (Improved AODV) that ensures giving timely and accurate information to drivers in V2V communication compare to AODV protocols in city scenarios of vehicular ad hoc networks. Proposed IAODV is defined as limited source routing up to two hops with backup route between source node and destination node. The performance of the proposed IAODV protocol is compared with basic AODV protocol in terms of Avg. End-to-End Delay, Packet Loss Ratio, Packet Delivery Ratio and Normalized Routing Load. Simulation results show that IAODV performs better than AODV protocol in given city scenarios of VANETs.

An improved AODV routing protocol for VANETs in city scenarios

Vehicular Ad Hoc Network (VANET) is appeared to be a new technology to integrate the susceptibility of vastly employed wireless networks to vehicles. The idea is to attain the ubiquitous connectivity for vehicles either through efficient vehicle-to-vehicle or vehicle-to-infrastructure communication that enables the Intelligent Transportation Systems (ITS). In order to design a suitable and efficient routing protocol in VANET, a comprehensive study on popular existing VANET routing protocols must be considered as a tangible need. In this paper, AODV, AOMDV, DSR, DSDV are exploited to be compared in terms of routing performance based on vehicle velocity and vehicle density.

http://isca.in/rjrs/archive/v2/i7/12.ISCA-RJRS-2013-054.pdf

Performance Analysis of AODV, AOMDV, DSR, DSDV Routing Protocols in Vehicular Ad Hoc Network

Vehicular Ad hoc networks are one of the most advanced technologies for intelligent transportation system that allow vehicle-vehicle to form multi-hop ad hoc networks. Routing is one of the challenges in vehicular ad hoc networks because of the frequent change of its topology structure. In this paper, we propose a routing protocol (AODV_BD) for vehicular ad hoc networks that improves the Ad hoc On-Demand Distance Vector (AODV) routing protocol by making it reduce the packet delay. The simulating experiments provide an efficient approach to estimate the routing protocol performance of a VANET.

Improved AODV routing protocol for vehicular Ad hoc networks

The paper presents the Vehicular Ad hoc Networks and the typical routing protocol: the ad hoc on-demand routing protocol (AODV) in mobile ad hoc networks and the optimized protocol AODV_OBD for protocol AODV; also presents a practical mobility model that enable the simulation experiment more veritable. Then it use network simulation tool(ns2) to simulate the two routing protocols in ad hoc networks based on Linux and then compares and analyses the simulation results and do performance evolution. We can infer that AODV_OBD routing protocol induces the packet delay to a certain extent compared with AODV routing protocol.

Baozhu Li

Papers

Improved AODV routing protocol for vehicular Ad hoc networks

Optimized AODV routing protocol for Vehicular Ad hoc Networks