Reflective communication using radio-frequency devices

Abstract

The present invention relates to a reflective communication system that allows information from wireless communication devices, such as radio-frequency identification devices (RFID), to be reflectively communicated to a receiver in lieu of using a separate communication system. A transmitter transmits a communication signal, having a carrier frequency, to the wireless communication device to provide power. The wireless communication device modulates a data signal onto the communication signal to form a reflected data signal. The wireless communication device reflects the reflected data signal directly to the receiver. In this manner, the process of communicating information from a wireless communication device is accomplished in one communication system rather than two. If the receiver also directly receives the communication signal from the transmitter, the receiver can determine the location of the wireless communication device relative to the transmitters.

1 - 53 . (canceled)  
   
   
       54 . A reflective communication system comprising: 
 a Bluetooth transmitter operable to transmit a communication signal having a first modulation;    a wireless communication device configured to receive the communication signal from the Bluetooth transmitter and reflectively modulate the communication signal with a data signal having a second modulation to form a reflected data signal; and    a receiver configured to receive the reflected data signal and the communication signal, wherein the receiver is adapted to form the data signal using the communication signal.    
   
   
       55 . The system of  claim 54 , wherein the receiver comprises a first antenna for receiving the communication signal and a second antenna for receiving the reflected data signal.  
   
   
       56 . The system of  claim 54 , wherein the receiver further comprises a mixer configured to mix the communication signal and the reflected data signal to form the data signal.  
   
   
       57 . The system of  claim 54 , wherein the data signal includes information stored in the wireless communication device.  
   
   
       58 . The system of  claim 57 , wherein the information stored in the wireless communication device is related to a container associated with the wireless communication device.  
   
   
       59 . The system of  claim 56 , wherein the receiver further comprises: 
 at least one filter configured to suppress a multiple of a frequency of the communication signal, the multiple of the frequency resulting from the mixing of the communication signal and the reflected data signal;    an amplifier configured to amplify the reflected data signal; and    a demodulator configured to demodulate the reflected data signal to form the data signal.    
   
   
       60 . A receiver for receiving a reflected data signal, the receiver comprising: 
 a transistor biased to provide a negative resistance at a gate terminal of the transistor, the transistor having at least one feedback component coupled between the gate terminal and a second terminal of the transistor;    an antenna coupled with the gate terminal and operable to receive a communication signal, wherein the communication signal causes the transistor to operate in a non-linear region, and wherein in response to receiving the communication signal, the transistor mixes the communication signal with a reflected data signal; and    a tuned circuit coupled to a third terminal of the transistor tuned to a modulation frequency of the reflected data signal and operable to demodulate the reflected data signal to obtain a data signal used to modulate the communication signal.    
   
   
       61 . The receiver of  claim 60 , wherein the transistor comprises a GaAs field effect transistor.  
   
   
       62 . The receiver of  claim 61 , wherein the second terminal of the transistor is a source terminal of the transistor and the third terminal of the transistor is a drain of the transistor.  
   
   
       63 . The receiver of  claim 60 , wherein the at least one feedback component comprises a capacitor.  
   
   
       64 . The receiver of  claim 60 , wherein the tuned circuit comprises one resistor and one capacitor connected in parallel with respect to one another.  
   
   
       65 . The receiver of  claim 60 , wherein the communication signal is transmitted by a Bluetooth transmitter.  
   
   
       66 . A reflective communication device comprising: 
 a Bluetooth transmitter configured to transmit a communication signal having a first modulation;    a receiver combined with the Bluetooth transmitter, the receiver configured to receive a reflected data signal modulated with a data signal having a second modulation;    a first antenna operatively coupled with the Bluetooth transmitter to transmit the communication signal;    a second antenna operatively coupled with the receiver to receive the reflected data signal; and    a mixer combined with the Bluetooth transmitter and the receiver, the mixer configured to mix the communication signal and the reflected data signal to remove the first modulation from the reflected data signal to form the data signal.    
   
   
       67 . The device of  claim 66 , wherein the Bluetooth transmitter transmits the communication signal to a wireless communication device.  
   
   
       68 . The device of  claim 67 , wherein the wireless communication device is a transponder.  
   
   
       69 . The device of  claim 66 , wherein the reflected data signal is formed from reflectively modulating the communication signal with the data signal.  
   
   
       70 . The device of  claim 67 , wherein the data signal includes information stored in the wireless communication device.  
   
   
       71 . The device of  claim 70 , wherein the information stored in the wireless communication device is related to a container associated with the wireless communication device.  
   
   
       72 . The device of  claim 66 , wherein the communication signal is input to the mixer using a direct connection between the Bluetooth transmitter and the receiver.  
   
   
       73 . The device of  claim 72 , wherein the communication signal directly input to the mixer is used as a local oscillator for mixing the communication signal and the reflected data signal.  
   
   
       74 . The device of  claim 66 , wherein the receiver further comprises a low noise amplifier.  
   
   
       75 . The device of  claim 66 , wherein the mixer produces, in response to the mixing of the communication signal and the reflected data signal, a new signal having a multiple of the frequency of the communication signal.  
   
   
       76 . The device of  claim 75 , wherein the receiver further comprises a filter to filter out the new signal having the multiple of the frequency of the communication signal.  
   
   
       77 . The device of  claim 75 , wherein the multiple of the frequency of the communication signal is two times the frequency.  
   
   
       78 . The device of  claim 77 , wherein the receiver further comprises an amplifier operable to amplify the data signal.  
   
   
       79 . The device of  claim 77 , wherein the receiver further comprises a demodulator to demodulate the data signal to obtain data.  
   
   
       80 . A method of receiving a reflected data signal, the method comprising: 
 receiving a communication signal having a first modulation from a Bluetooth transmitter;    receiving a reflected data signal formed from reflectively modulating the communication signal with a data signal having a second modulation; and    removing said communication signal from said reflected data signal to form said data signal.    
   
   
       81 . The method of  claim 80 , wherein receiving the communication signal comprises receiving the communication signal using a first antenna.  
   
   
       82 . The method of  claim 80 , wherein receiving the reflected data signal comprises receiving the reflected data signal using a second antenna.  
   
   
       83 . The method of  claim 80 , wherein reflectively modulating the communication signal with the data signal comprises modulating the communication signal with the data signal including information stored in a wireless communication device.  
   
   
       84 . The method of  claim 80 , wherein removing the communication signal from the reflected data signal comprises demodulating the second modulation from the reflected data signal.