حداکثر طول عمر شبکه مبتنی بر مسیریابی بهره وری انرژی در شبکه های ادهاک Maximizing the Network Life Time Based on Energy Efficient Routing in Ad Hoc Networks

1 Introduction In ad hoc networks, the operations of nodes are based on the transmission range and battery power. Each node on the networks performs routing operations which provides the communication between different nodes. All nodes in the network can transmit their data to their intermediate nodes or to the destination, if it has enough energy and the nodes are within the transmission range. If the mobile node does not have the energy it cannot transmit the data or participate in the network operation. So node energy consumption should be provided for efficient data transmission. The network liftime can be increased by using energy efficient routing mechanism in multi hop networks for data transfer. The extension of battery life time of node improves the nodal energy which increases the network performances. The mobile nodes in ad hoc networks are self-managed where they can work in remote areas without any maintenance or repair. Usually the data transfer from source to sink is carried out by using multiple hops where minimum energy consumption should be provided per packet transfer between the intermediate nodes which results in a reduction of total expenditure of energy per packet transmission. The death of mobile nodes in the ad hoc networks will adversely affect services. Figure 1 shows multi hop data transmission where the source will send route request to all the nodes participating in the network, when the request reaches the destination it will send route reply along with acknowledgement. The mobile nodes will dissipate energy when data’s are transmitted or received by the nodes. In multi hop transmission, the data from source to sink is reached through different intermediate nodes by considering the route request and route reply. The route request (RREQ) is sent by the source to the destination as to whether it will have free routes for data transmission for providing multi hop communication [1] from source to destination. The destination will send a route reply (RREP) to the source which will have the information whether a free route is available or not. Based on the RREP the source will find a route with minimum hop count. The above multi hop communication only four hops are required for the data from source to reach destination. Here the source will send the data to node 1–node2–node3 and finally to the destination. Minimum number of hops from source to destination will decrease the time delay which improves the network performances. The mobile nodes in ad hoc networks can be function as both the data router and data originator, if some nodes does not have enough energy there may occur changes in topology which reorganize the network, necessitating data to be rerouted and resulting in high energy consumption, calling for more energy from other nodes and causing decrease in network life time. By considering the residual energy for data transfer, the network life time can be improved.