PBO based Enhancement of DSRC for VANET’s Safety Application

VANETs are a form of mobile ad-hoc networks to provide communications among nearby vehicles and between vehicles and nearby fixed equipment. Safety applications like collision alert merge assistance, road condition warning, etc requires messages to be propagated from the point of occurrence to the target vehicles with very low latency. DSRC is a two-way short-to-medium range wireless communication capability that permits very high data transmission critical in communications-based active safety applications. The previous work which we taken into consideration is to develope analytical model for the reliability of a dedicated short-range communication (DSRC) control channel (CCH) to handle safety applications in vehicular ad hoc networks (VANETs).In their work, they enhance the conventional dedicated short-range communication (DSRC) for VANET safety applications. They userealistic vehicular traces for simulation and validation of proposed model and enhanced algorithm.So in our work, we will enhance this by trained our system using back propagation model to increase system reliability in terms of the probability of successful reception of the packet and the delay of emergency messages in a harsh vehicular environment. Keywords— AMBA, PBO, CCH, DSRC, VANET Didar Singh et al, International Journal of Computer Science and Mobile Computing, Vol.4 Issue.8, August2015, pg. 33-43 © 2015, IJCSMC All Rights Reserved 34 INTRODUCTION A wireless ad hoc network is a decentralized type of wireless network [6]. The network is ad hoc because it does not rely on a pre existing infrastructure, such as routers in wired networks or access points in managed (infrastructure) wireless networks. Instead, each node participates in routing by forwarding data for other nodes, so the determination of which nodes forward data is made dynamically on the basis of network connectivity. Figure 1: Wireless Adhoc Network [6] VANET Today’s Internet has been developed for more than forty years. Recently many network researchers are studying networks based on new communication techniques, especially wireless communications. Wireless networks allow hosts to roam without the constraints of wired connections. People can deploy a wireless network easily and quickly. End users can move around while staying connected to the network. Wireless networks play an important role in both military and civilian systems [13]. VANETs stand for Vehicular Ad hoc Networks. Vehicular implies “mobility”. Ad hoc is a Latin word and it means “for this only”. VANET is an autonomous collection of Vehicular routers or nodes that communicate over wireless links. VANET is an Infrastructure-less wireless network. The routers or nodes moves randomly and organize themselves arbitrarily. The nodes directly communicate via wireless links within each other’s radio range, while that are distant apart use other nodes as relay, in a multi-hop routing function. As the nodes are Vehicular, the structure of the network changes dynamically and unpredictably over time. Ad-hoc networks are self-configuring and self-organizing, so to maintain communication between nodes in the network, each node behaves as a transmitter, a host and a router A Vehicular ad hoc network (VANET)[15] is a self-configuring infrastructure less network of Vehicular devices connected by wireless. Each device in a VANET is free to move independently in any direction, and will therefore change its links to other devices frequently. Each must forward traffic unrelated to its own use, and therefore be a router. The primary challenge in building a VANET is equipping each device to continuously maintain the information required to properly route traffic. Such networks may operate by themselves or may be connected to the larger Internet. PROTOCOL Ad–hoc on demand distance vector routing (AODV)[2] is a stateless on-demand routing protocol .The Ad-hoc On Demand Distance Vector (AODV) classified under reactive protocols. The operation of the protocol is divided in two functions, route discovery and route maintenance. In Ad-hoc routing, when a route is needed to some destination, the protocol starts route discovery. Then the source node sends route request (RREQ) message to its neighbors. And if those nodes do not have any information about the destination node, they will send the message to all its neighbors and so on. And if any neighbor node has the information about the destination node, the node sends route reply (RREP) message Didar Singh et al, International Journal of Computer Science and Mobile Computing, Vol.4 Issue.8, August2015, pg. 33-43 © 2015, IJCSMC All Rights Reserved 35 to the route request (RREQ) message initiator. On the basis of this process a path is recorded in the intermediate nodes. This path identifies the route and is called the reverse path. Since each node forwards route request (RREQ) message to all of its neighbors, more than one copy of the original route request (RREQ) message can arrive at a node. A unique id is assigned, when a route request (RREQ) message is created. When a node received, it will check this id and the address of the initiator and discarded the message if it had already processed that request. Node that has information about the path to the destination sends route reply(RREP) message to the neighbor from which it has received route request(RREQ) message. This neighbor does the same. Due to the reverse path it can be possible. Then the route reply message travels back using reverse path. When a route reply message reaches the initiator the route is ready and the initiator can start sending data packets. Figure 2: PropaGPBOtion of Route Request (RREQ) packet [2] Figure 3: Path taken by Route Reply (RREP) packet [2] Khalid Abdel Hafez [16] An analytical model for the reliability of a dedicated short-range communication (DSRC) control channel (CCH) to handle safety applications in vehicular ad hoc networks (VANETs)is proposed. Specifically, the model enables the determination of the probability of receiving status and safety messages from all vehicles within a transmitter’s range and vehicles up to a certain distance, respectively. The proposed model is built based on a new mobility model that takes into account the vehicle’s follow-on safety rule to derive accurately the relationship between the average vehicle speed and density. Moreover, the model takes into consideration 1) the impact of mobility on the density of vehicles around the transmitter, 2) The impact of the transmitter’s and receiver’s speeds on the system reliability, 3) The impact of channel fading by modeling the communication range as a random variable. 4) The hidden terminal problem and transmission Collisions from neighboring vehicles. It is shown that the current specifications of the DSRC may lead to severe performance degradation in dense and high-mobility conditions. Therefore, an adaptive algorithm is introduced to increase system reliability in terms of the probability of successful reception of the packet and the delay of emergency messages in a harsh vehicular environment. The proposed model and the enhancement algorithm are validated by simulation using realistic vehicular traces. 1 2