Patent ID: 8155044
Filing Date: 2012-04-10
Classification: H04W

Abstract:
1. A method for broadcasting an alert packet in a wireless multi-hop network of nodes, comprising: sensing an event in a source node of the network; broadcasting an alert packet in response to sensing the event; receiving the alert packet in a set of candidate nodes within a broadcast range of the source node; inferring, in each candidate node, a distance between the candidate node and the source node based on a receive power of the received alert packet; determining, in each candidate node, a priority for rebroadcasting the alert packet, wherein the priority is based on the distance to minimizing a probability of collisions while rebroadcasting the alert packet and extend a range of the rebroadcasting; and determining back-off times for rebroadcasting packets for the set of the candidate nodes based on the priority of each candidate node and a back-off probability distribution, wherein the back-off probability distribution is a non-uniform distribution among the nodes with the same priority, such that a cumulative probability for the nodes increases with the distance from the source node.