This article puts forward a new scheme to control message redundancy efficiently in delay tolerant mobile Ad-hoc networks （MANET）. The class of networks generally lacks end-to-end connectivity. In order to improve t...This article puts forward a new scheme to control message redundancy efficiently in delay tolerant mobile Ad-hoc networks （MANET）. The class of networks generally lacks end-to-end connectivity. In order to improve the efficiency that messages are delivered successfully, multiple message copies routing protocols are usually used, but the network load is increased due to a large number of message redundancies. In the study, by using counter method, every node adds an encounter counter based on epidemic routing scheme. The counter records the number which the node encounters other nodes with the same message copy. If the counter of a node reaches tbe installed threshold, the node removes the copy. Theoretical analysis gives a lower bound of threshold in delay tolerant MANET. According to the lower bound of threshold, a rational threshold is installed in real environment. With proposed scheme message copies decrease obviously and are removed completely finally. The successful delivery efficiency is still the same as epidemic routing and the redundant copies are efficiently controlled to a relatively low level Computer simulations give the variation of message copies concerning different thresholds in fast and slow mobility scenes.展开更多
A fault-tolerant and heuristic routing algorithm for faulty hypercube sys-tems is described. To improve the efficiency, the algorithm adopts a heuristic backtracking strategy and each node has an array to record its a...A fault-tolerant and heuristic routing algorithm for faulty hypercube sys-tems is described. To improve the efficiency, the algorithm adopts a heuristic backtracking strategy and each node has an array to record its all neighbors'faulty link information to avoid unnecessary searching for the known faulty links. Furthermore, the faulty link information is dynamically accumulated and the technique of heuristically searching for optimal link is used. The algo rithm routes messages through the minimum feasible path between the sender and receiver if at Ieast one such path ekists, and ta.kes the optimal path with higher probability when faulty links exist in the faulty hypercube.展开更多
基金supported by the Hi-Tech Research and Development Program of China (2007AA01Z429,2007AA01Z405)the National Natural Science Foundation of China (60702059,60872041,11061035)
文摘This article puts forward a new scheme to control message redundancy efficiently in delay tolerant mobile Ad-hoc networks （MANET）. The class of networks generally lacks end-to-end connectivity. In order to improve the efficiency that messages are delivered successfully, multiple message copies routing protocols are usually used, but the network load is increased due to a large number of message redundancies. In the study, by using counter method, every node adds an encounter counter based on epidemic routing scheme. The counter records the number which the node encounters other nodes with the same message copy. If the counter of a node reaches tbe installed threshold, the node removes the copy. Theoretical analysis gives a lower bound of threshold in delay tolerant MANET. According to the lower bound of threshold, a rational threshold is installed in real environment. With proposed scheme message copies decrease obviously and are removed completely finally. The successful delivery efficiency is still the same as epidemic routing and the redundant copies are efficiently controlled to a relatively low level Computer simulations give the variation of message copies concerning different thresholds in fast and slow mobility scenes.
文摘A fault-tolerant and heuristic routing algorithm for faulty hypercube sys-tems is described. To improve the efficiency, the algorithm adopts a heuristic backtracking strategy and each node has an array to record its all neighbors'faulty link information to avoid unnecessary searching for the known faulty links. Furthermore, the faulty link information is dynamically accumulated and the technique of heuristically searching for optimal link is used. The algo rithm routes messages through the minimum feasible path between the sender and receiver if at Ieast one such path ekists, and ta.kes the optimal path with higher probability when faulty links exist in the faulty hypercube.
