Patent ID: 8718923

Claim:
A method of estimating a number of physical objects clustered together, wherein each object includes wireless communication circuitry capable of receiving and transmitting radio frequency (RF) signals, the method comprising: causing each of a plurality of physical objects to generate a radio frequency (RF) transmission during a respective transmission timeslot; by each physical object, generating Received Signal Strength Indication (RSSI) values for the RF transmissions received by that respective physical object from the other physical objects, such that each physical object receives a transmission from, and generates an RSSI value for, every other physical object of the plurality of physical objects; by a node, collecting and collectively analyzing the RSSI values generated by the plurality of physical objects, wherein collectively analyzing the RSSI values comprises applying a clustering algorithm; and estimating how many of the plurality of physical objects are clustered together based on the collective analysis of the RSSI values generated by the plurality of physical objects.