Patent ID: 8767696

Claim:
A method of medium access control for a wireless communication network having a plurality of wireless nodes, each wireless node having a duty cycle which controls a sleep mode and a wake-up mode, the method comprising: detecting an alert event at a source node; classifying each node of the plurality of nodes as a backbone node if a remaining energy of the node is greater than a pre-determined energy threshold, wherein the backbone nodes are available for relaying data for other nodes; classifying each node of the plurality of nodes as a non-backbone node if a remaining energy of the node is less than or equal to the pre-determined energy threshold, wherein the non-backbone nodes are available to exchange information with other nodes and are not available for relaying data for other nodes; determining a communication path between a source node and a destination node; identifying each node in the communication path; at each node in the communication path, changing the duty cycle of the node and transmitting an alert message to each wireless node adjacent to the transmitting node to indicate the change in duty cycle; at each adjacent node, storing the duty cycle change of the transmitting node; and transmitting a message from the source node to the destination node via one or more of the backbone nodes through the identified communication path.