Energy-efficient network protocol and node device for sensor networks

摘要

A method for changing routing responsibilities for a node in a tree-like wireless network 10 of nodes 200, 400 that exchange information between each other and ultimately with a main node 100, comprising: when communication with the upstream node is compromised, broadcasting a first message to inform downstream nodes that a repair is underway; and initiating a link to another node in a manner dependent on the power availability of the node. If attempts to join other nodes fail a second message, preferably a resign message, may be broadcast alerting downstream nodes to join at other nodes. Downstream nodes may receive messages from candidate upstream nodes indicating their routing responsibility which may be used to select a new upstream node. The available power may be compared with three thresholds. The comparison may result in: terminating all over-the-air transmissions; only transmitting local data; forwarding data to a node without joining that node.