| Summary: | 碩士 === 國立臺灣師範大學 === 資訊工程學系 === 102 === In geographic routing, not much effort has been given to improving position update mechanism used by nodes in wireless Ad-Hoc networks which is an important issue in order to precisely maintain the geographic position of nodes. Nodes are periodically broadcasting beacon updates that contain geographic location coordinates to the nodes in their vicinity. This is an accepted scheme for maintaining neighbor’s positions. We are solving the problem of high beacon overhead caused by generation of beacons while considering mobility and traffic load of the network. For example, if the beacon interval is too short for nodes that move very slow, i.e. not rapidly changing position, periodic beaconing will create unnecessary amount of beacon updates. In the same way, nodes which are broadcasting lot of data packets will generate the same amount of beacons as the nodes that have fewer data packet to transmit which leads to needless waste of energy. To make progress on these problems, we propose Adaptive Energy-Efficient (AEE) mechanism for geographic routing. Based on mobility and traffic load of the network, AEE adapts the beaconing interval to the value that corresponds to the network’s demands. We have embedded AEE into well know Greedy Perimeter Stateless Routing protocol (GPSR), and compared it with regular GPSR. We ran extensive simulations in Network Simulator 2 (NS-2) for both networks with high and low initial energy level. Results have shown that AEE reduces beacon overhead up to 90 percent, AEE also reduces energy consumption and the number of packet collision up to 83 percent, without worsening packet delivery fraction of the network. This adaptive method that reduces the number of collision and prolongs the battery usage of each node in the network can be very useful for MANET or VANET where system is completely ad-hoc and no infrastructure is used and nodes are relying on their own power sources.
|
|---|
