Patent ID: 8363569

Claim:
A method of joining nodes from a first and a second subnet into a network, wherein each subnet includes two or more nodes and wherein each subnet is in a different, non-overlapping wake-sleep timeslot, the method comprising: establishing a probability that a node within the first subnet will enter scout mode during which the node will wake between regular synchronized wake periods of the subnet, wherein the probability is less than 100%; if the node enters scout mode, broadcasting a message from the node in scout mode to other nodes inviting nodes in other subnets to join with the first subnet, wherein the message includes the node's network identifier; and detecting, within a detecting node in the second subnet, the message broadcast by the node in scout mode; and determining whether nodes in the second subnet have the same network identifier as the network identifier in the message broadcast by the node in scout mode; and if the nodes in the second subnet have the same network identifier as the network identifier in the message broadcast by the node in scout mode, combining the nodes in the first and second subnets into a combined network; wherein each node generates a first and second random number during its sleep interval, wherein, if the first random number is less than a threshold value, the node enters scout mode during that sleep interval, wherein the second random number defines when the node enters scout mode during that sleep interval; and wherein combining includes: determining which subnet has fewer nodes; if the first subnet has fewer nodes than the second subnet, instructing all nodes in the first subnet to synchronize to the second subnet; and if the first subnet has more nodes than the second subnet, instructing all nodes in the second subnet to synchronize to the first subnet.