System and method for short-distance wireless communications, and applications thereof

Abstract

A first portable wireless communication device enters a PICONET and establishes unencrypted communications with a second wireless communication device, the PICONET master. The first portable wireless communication device transmits identification information to the second wireless communication device using a conventional short-distance communications protocol. The second wireless communication device transmits, in a novel FEMTONET communications mode, an encryption key to the first portable wireless communication device. The first portable wireless communication device then securely transmits encrypted messages based on the encryption key to the second wireless communication device using the conventional short-distance communications protocol.

1 . A system for conducting sale transactions using short-range wireless communications, comprising: 
 a point-of-sale terminal that includes a wireless communication device having a locator that analyzes radio frequency signals received via a plurality of radio frequency paths to determine a spatial location from which the radio frequency signals originated; and    a portable consumer wireless communication device that communicates with the wireless communication device of the point-of-sale terminal using radio frequency signals,    wherein the wireless communication device of the point-of-sale terminal transmits a key by radio frequency signals that arrive via a plurality of radio frequency paths substantially in-phase within a selected communication space surrounding the portable consumer wireless communication device, the communications space being centered around the spatial location determined by the locator, and substantially out-of-phase at locations outside the selected communication space surrounding the portable consumer wireless communication device, thereby allowing the key to be received by the portable consumer wireless communication device.    
     
     
         2 . The system of  claim 1 , wherein the selected communication space surrounding the portable consumer wireless communication device is an approximately spherical volume.  
     
     
         3 . The system of  claim 2 , wherein the approximately spherical volume has a diameter of less than three feet.  
     
     
         4 . The system of  claim 3 , wherein the approximately spherical volume has a diameter of less than one foot.  
     
     
         5 . The system of  claim 1 , wherein the locator carries out a time-reversal-mirror function.