Apparatus and method for enabling communications among unsynchronized wireless devices

A device for communicating over wireless network, configured to periodically rendezvous with at least one other device over the wireless network, where an activation schedule of the device is not synchronized with an activation schedule of the at least one other device, the device comprising:

• a memory for storing a rendezvous algorithm and information identifying a number of time units in each cycle of a plurality of cycles;
• and
• a processor for creating an activation sequence having a plurality of active time units in each cycle, according to the rendezvous algorithm, during which the device enters an active mode, the activation sequence having a first active time unit of the plurality of active time units in each cycle occupy a same position in the cycle as an active time unit in a previous consecutive cycle, and a second active time unit of the plurality of active time units in each cycle occupy a different position in the cycle than any active time unit in the previous consecutive cycle,
• wherein the device is in an inactive mode during a plurality of inactive time units of each cycle, a sum of the plurality of active time units and the plurality of inactive time units equaling the number of time units in each cycle.

A method of enabling a first wireless device to rendezvous with a second wireless device over a wireless network, where activation schedules of the first wireless device and the second wireless device are not synchronized, the method comprising:

• determining two super-frames [Xi, Xi+1] in each cycle of a plurality of communication cycles, during which the first wireless device enters an active mode, according to the following equation, in which i is an integer, C is a number of super-frames in each cycle and S is a constant having a value between 1 and C−1:
• Xi+1=(Xi+S)mod C,
• and
• determining two super-frames [X′i, X′i+1] for each cycle during which the second wireless device enters an active mode, according to the following equation, in which S′ is a constant having a value between 1 and C−1 and S′ is not necessarily equal to S:
• X′i+1=(X′i+S′)mod C,
• wherein the first wireless device and the second wireless device are able to at least one of locate and communicate with each other when both the first wireless device and the second wireless device are in the active mode simultaneously.