International Journal of Technical Research and Applications e-ISSN: 2320-8163, www.ijtra.com Volume 2, Issue 5 (Sep-Oct 2014), PP. 78-81 78 | Page MINIMUM DELAY BASED ROUTING PROTOCOL IN MANET Abhishek Jain, Ashish Jain, Rohit Thete, Akshay Shelke, Harshada Mare BE, Department of Computer Science, MIT Academy of Engineering, Pune, India abhi.jain2210@gmail.com, ashishomatic@gmail.com, rt90thete@gmail.com, shelkeakshay@gmail.com, harsha_mare@hotmail.com Prof. S.A. Jain Asst. Professor, Department of Computer Science, MIT Academy of Engineering, Pune, India sajain@comp.maepune.ac.in Abstract—Broadcasting is a fundamental and effective broadcasting technique in mobile ad hoc networks (MANET). Simple flooding technique is used in conventional ad hoc protocols for route discovery in which the mobile node blindly rebroadcast the packets until route to destination is established. But this causes redundant transmission of control packets leading to collision and contention in network. This problem is referred as broadcasting storm problem. To overcome this problem, neighbor coverage based probabilistic rebroadcasting protocol is used which combines the merits of neighbor coverage knowledge and probabilistic method. In order to effectively exploit the neighbor coverage knowledge, rebroadcast delay is used to determine the forwarding order and then we calculate rebroadcast probability by combining additional coverage ratio and connectivity factor. This approach can significantly reduce the end-to-end delay by reducing the routing overhead and increasing packet delivery ratio to improve routing performance of the network. Index Terms—MANET, Rebroadcast Probability, Control Packets, Neighbor Coverage Knowledge, Broadcasting, Routing Overhead. I. INTRODUCTION MANET is a self-configuring, infrastructure-less network of mobile nodes which are connected without wires. But due to high mobility of nodes, link breakages may occur which will lead to frequent path failures and route discoveries. This increases the overhead of routing protocols, effectively increasing end-to-end delay and reduces the packet delivery ratio [1]. So reducing the routing overhead in MANET is essential problem. In conventional ad hoc on-demand distance vector routing protocol (AODV) [2] method, simple flooding is used for route discovery where nodes blindly rebroadcast received route request (RREQ) packet until route to the destination is established. While this method has many advantages, but due to redundant retransmission causes broadcast storm problem [3]. Some methods have been proposed to optimize broadcast problem and Williams and Camp [4] has categorized broadcasting protocol into four classes: “simple flooding, probability-based methods, area based methods and neighbor knowledge methods.” Since limiting the number of rebroadcast can effectively optimize the broadcasting [3]; and the neighbor knowledge methods perform better than the area-based method and the probability based method [6]. Combining merit of neighbor knowledge and probabilistic based method we propose neighbor coverage based probabilistic rebroadcast (NCPR) protocol. So, (1) In order to effectively exploit the neighbor coverage knowledge, rebroadcast delay is used to determine the forwarding order, (2) with the help of uncovered neighbor (UCN) set, additional coverage ratio and connectivity factor is calculated the determine the rebroadcast probability. Additional coverage ratio is a ratio of the covered node by single broadcast to the total number of neighbor and connectivity factor is relationship of network connectivity and number of neighbor of given node. The rest of this paper is organized as follows: Section 2 describes the proposed system and implementation Detail. Section 3 is Simulation Results. In Section 4 we have concluded with our observations. II. PROPOSED SYSTEM In this section, first calculate rebroadcast delay to determine it forwarding order and set the timer according to the delay. Second, calculate rebroadcast probability with the help of neighbor knowledge method by multiplying additional coverage ratio and connectivity factor, which requires that each node needs its 1-hop neighborhood information. A. Uncovered Neighbor Set and Rebroadcast Delay When source node S send RREQ packet to the node ni, it attaches its neighbor list along with RREQ packet. Node ni uses the neighbor list in the RREQ packet to estimate the number of neighbor nodes that are not covered by RREQ packet of node S. The uncovered neighbor set U(ni) of node ni is given as: } { )] ( ) ( [ ) ( ) ( S S N n N n N n U i i i     (1) Where N(ni) and N(S) are neighbor set of node S and ni. S is the node which send the RREQ packet to node ni. But due to broadcasting characteristics, node may receive duplicate RREQ from its neighbor. So when node receives RREQ packet, a rebroadcast delay is set according to the neighbor list in RREQ packet and its own neighbor list. The rebroadcast delay T(ni) is defined as follows: ) ( * ) ( ) ( ) ( ) ( 1 ) ( i i i i i r n Tr MaxDelay n T n N n N S N n T     (2) Where Tr (ni) is delay ratio of node ni and MaxDelay is a small constant delay in the network.|.| is the number of elements in a set.