Node Transition Probability based routing protocol for Mobile Adhoc Networks- Implementation and a Comparitive Performance Analysis for Various Mobility Models 

 u Deepa.T  v  Gayathri Narayanan     w   Jayanthi.T        x  Renuka.P.T

                   Mobile ad hoc network is an autonomous system of mobile nodes connected dynamically in an arbitrary manner by wireless links. The mobile nodes can dynamically form a network without the aid of any pre-existing infrastructure or centralized administration. There is no static infrastructure such as base station. Ad hoc networks are characterized by multi-hop wireless connectivity, frequently changing network topology and the need for efficient adaptive routing protocols.

                        Routing algorithms for existing networks have to be designed specifically to provide the kind of dynamic, self-starting and self-organizing behaviour needed for ad hoc networks. In the existing protocols such as DSR and AODV, the control packets contribute to the network congestion during times of high load. To overcome this drawback, a new algorithm, which minimizes control overhead during high traffic and scalable to large networks has been proposed. The performance of these algorithms is studied under various mobility models.

                        In all existing algorithms, the control overhead contributes to the overall inefficiency of bandwidth and power utilization. We propose a new algorithm based on what is called Node Transition Probability (NTP), which is computed using the received power at a particular node from all other nodes.

                        Initially all the nodes including the newly joined ones perform flooding to construct a node transition probability matrix. A node floods to all other nodes within its transmission range. All nodes that hear the flooding packets reply to their corresponding source node. Flooding is performed ‘n’ times and each node obtains the values of power with which its neighbour nodes responded during each flooding and computes the NTP and form a matrix. A node forwards a packet, if it is not the target, to its neighbour node. This process is repeated until the destination is reached. The node that has replied with the highest power level for the maximum number of times has the highest probability of being the next hop to the source node. Each node sends back an acknowledgement packet.                  

                        In the performance evaluation of a protocol for an ad hoc network, the protocol should be tested under realistic conditions and realistic movements of the mobile users (i.e., a mobility model). Thus, NTP is implemented and a comparative performance analysis of the NTP based routing protocol for mobile ad hoc networks is made using the various mobility models.