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|Title||Improved AODV Routing Protocol to Cope with High Overhead in High Mobility MANETs|
Ad-hoc On-demand Distance Vector (AODV) is the most popular routing protocol for mobile ad-hoc networks (MANETs). According to its nature, AODV makes route discovery when there is data to send at source and source doesn’t have route to the specified destination. To discover a route to a destination, AODV floods the network with control messages like RREQ, and RREP which may result in unnecessarily large number of control messages that travel through the network and consume network resources such as bandwidth, and node processing power. This thesis improves AODV protocol by limiting the number of AODV control messages forwarded though the network during the route discovery process. By using Global Positioning System (GPS), each node knows its location and its traveling speed stamped by time. Each source node propagates its location and speed stamped by time to other nodes in the network by adding its location information to the generated RREQ packet and HELLO messages. Each node in the network stores location information of other nodes. We propose two protocols to limit control messages flooding in the Ad-hoc networks. The first proposed protocol which is called AODV-LAR uses alternative request region defined in LAR. It uses location information to estimate the location of the destination and then estimates the rectangular search region. To increase the accuracy of the estimation of the search region, the first proposed protocol takes into account the distance that destination node moves during discovery process by adding tolerance factor to the search region. In the second proposed protocol which is called AODV-Line, the intermediate nodes decide to participate in route discovery process according to their distance from the line connecting the source and destination locations without the need of the information about the destination traveling speed. The route discovery search region is adjusted based on the location information of both source and destination. To reduce the delay of route discovery process, AODV-LAR defines an equation to estimate the initial TTL of the RREQ message. We evaluate the performance of the two proposed protocols using two simulation scenarios. The simulation was done using JIST/SWANS simulator. Different performance metrics were measured including routing overhead, number of RREQ messages, delivery ratio, normalized routing load, and delay. The results were compared to the original AODV routing protocol. The results shows that the two proposed protocols outperform the original AODV, where the results report a valuable reduction of overhead , number of RREQ messages sent through the network, and reduction in delay compared to the original AODV. Results also show that the delivery ratio in the proposed protocols is comparable to the delivery ratio in the original AODV protocol.
|Publisher||the islamic university|
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