System and method for media access control for a duty cycle network

1. 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.

2. The method of claim 1 further comprising the step of:

at each node in the communication path, returning to the original duty cycle of the node by transmitting an alert message to each wireless node adjacent to the transmitting node in the communication path to indicate the change in duty cycle.

3. The method of claim 1 wherein the alert event is provided by a sensor.

4. The method of claim 3 wherein the sensor monitors environment conditions.

5. The method of claim 3 wherein the sensor is an intrusion detector.

6. A method of medium access control for a wireless communication network having a plurality of wireless nodes, each wireless node having a sleep mode and a wake-up mode and being powered by an energy source, the method comprising:

classifying some of the plurality of nodes into backbone nodes and some of the plurality of nodes as non-backbone nodes based as a function of the remaining amount of energy at each node, wherein a backbone node has a remaining energy that is greater than a pre-determined energy threshold, and a non-backbone node has a remaining energy that is less than or equal to the pre-determined energy threshold;

making the backbone nodes available for relaying data for other nodes; and

making the non-backbone nodes available to exchange information with other nodes and making the non-backbone nodes not available for relaying data for other nodes.

7. The method of claim 6 wherein the step of classifying is performed periodically.

8. The method of claim 6 wherein the backbone nodes and the non-backbone nodes are made available for transferring their own data.

9. A system providing medium access control for a wireless communication network, the system comprising:

a plurality of wireless nodes, each wireless node having a duty cycle which controls a sleep mode and a wake-up mode; and

a processor programmed to:

detect an alert event at a source node;

classify 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;

classify 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;

determine a communication path between a source node and a destination node;

identify each node in the communication path;

at each node in the communication path, change 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, store the duty cycle change of the transmitting node; and

transmit a message from the source node to the destination node via one or more of the backbone nodes through the identified communication path.

10. A system for providing medium access control for a wireless communication network, the system comprising:

a plurality of wireless nodes, each wireless node having a sleep mode and a wake-up mode and being powered by an energy source; and

processor programmed to:

classify some of the plurality of nodes into backbone nodes and some of the plurality of nodes as non-backbone nodes based as a function of the remaining amount of energy at each node, wherein a backbone node has a remaining energy that is greater than a pre-determined energy threshold, and a non-backbone node has a remaining energy that is less than or equal to the pre-determined energy threshold;

make the backbone nodes available for relaying data for other nodes; and

make the non-backbone nodes available to exchange information with other nodes and making the non-backbone nodes not available for relaying data for other nodes.