Abstract: A first sensor node 100 includes a radio for wireless communications; a sensor module 204 to sense a selected parameter; and a scheduler 228 that selects a listen time for the first sensor node, such that, during the listen time, the radio is activated and able to receive wireless signals and, during a time other than the listen time, the radio is deactivated and unable to receive wireless signals, and causes transmission to a second sensor node of a first message. The first message includes a time offset from a transmission time of the first message, the time offset indicating a timing of a first listen time for the first sensor node. The first node 100 receives, from the second sensor node, a responsive second message including a time based on the time offset to transmit the second message.

Abstract: In one embodiment, a first sensor node 100 includes a radio to effect wireless communications; a sensor module 204 to sense a selected parameter; and a scheduler 228 that selects a listen time for the first sensor node, such that, during the listen time, the radio is activated and able to receive wireless signals and, during a time other than the listen time, the radio is deactivated and unable to receive wireless signals, and causes transmission to a second sensor node a first message. The first message includes a time offset from a transmission time of the first message, the time offset indicating a timing of a first listen time for the first sensor node. In response, the node 100 receives, from the second sensor node, a second message, with the time selected by the second sensor node to transmit the second message to the first sensor node being based on the time offset.