Multipoint Relay Selection using Trilateration Technique Jeril Kuriakose, and Sandeep Joshi School of Computing and Information Technology Manipal University Jaipur, India jeril@muj.manipal.edu Abstract— Mobile network had become the broad area in wireless network, because of its reduced deployment cost, easy to use, and relief from wires. Routing is carried out in a mobile network with the help of broadcasting. There are several broadcasting schemes among which multipoint relay (MPR) is found to be the effectual and uncomplicated scheme. The MPR broadcast scheme works with the help of selected MPR nodes. The selected node can be any node in the network, and provides no assurance about its honesty. In our paper, we have discussed a novel approach in MPR node selection, by adding a security feature before the node selection request is being sent to the neighboring node. Future events are also being discussed. Keywords— Multipoint relay; trilateration; attacks; security. I. INTRODUCTION A large consideration is being given to the mobile network these days, due to their self-organizing and infrastructure less capabilities. In using a mobile network, a network can formed anywhere and at any time without any additional requirements; whereas this would not be possible in a cellular or wired network. Routing in a mobile network is carried out with the help of broadcasting, and a MPR broadcasting scheme [1] is considered as the effectual and uncomplicated scheme. As a mobile network is an infrastructure less network, the data is transferred with the help of neighboring nodes. During routing a broadcast message is sent from the sender node for identifying the destination node. During a broadcast message consumes energy and floods the network, and this can be overcome by using MPR broadcast scheme. MPR scheme broadcasts the message only to the selected MPR nodes, which in turn uses other MPR nodes to identify the destination nodes, thus reducing flooding and conserving energy. Any of the neighboring nodes can be selected as the MPR node during MPR node selection, thus increasing the vulnerability during node selection. In this paper, we have added an additional security alternative during the node selection. Before the MPR node selection is carried out, the neighboring nodes are checked using trilateration technique to identify vulnerable node. Trilateration technique [2] uses location coordinates to identify the vulnerable node. In a mobile network, each mobile node is equipped with special hardware’s to identify its location reference, and by using trilateration technique in our work, need for additional hardware for security is not required. When a MPR node is under Sybil attack [3], the attacker can create various arbitrary identities or imitate other nodes identities in the network /MAC layer. A MPR node under black hole attack [4] makes the nodes to magnetize all the traffic in the network, it does that by publicity advertising that it has the shortest path to the destination. If a MPR node is under wormhole attack [5] it distracts the route from one section of network to a different section by using a wormhole link (tunnel) between two parts of the section. The rest of the paper is organized as follows: section 2 demonstrates how a MPR node is selected, section 3 discusses the mathematical scheming of trilateration technique. Section 4 shows the results and section 5 concludes the paper. II. MPR NODE SELECTION The selection of MPR nodes is began by choosing a random node r. To select the MPR nodes for the node r, the set all one hop proximity nodes are taken as P(r), and the set of all two hop neighboring nodes of the node r are taken as P 2 (r). All the two hop neighbors of the node r is represented with out-degree O(s), where s is the one hop neighbor of r. Fig. 1 shows initial flooding problem. The selection of MPR node is carried out as follows: [1] Fig. 1. Initial MPR selection  Initially MPR is an empty set MPR(r), where r is the random node.  For each node in P(r), the out-degree O(s) is calculated.  The nodes in P(r) are added to the MPR(r) set, which are the only node by which the nodes in P 2 (r) can be reached to r.  If some nodes are not covered in P 2 (r) through P(r), in the set MPR(r):