REFLECTIVE COMMUNICATION USING RADIO-FREQUENCY DEVICES

• US 20080045150A1
• Filed: 09/14/2007
• Published: 02/21/2008
• Est. Priority Date: 06/04/2002
• Status: Active Grant

• Current Assignee: Mineral Lassen LLC (Intellectual Ventures LLC)
• Original Assignee: Mineral Lassen LLC (Intellectual Ventures LLC)
• Inventors: Forster, Ian
• Granted Patent: US 7,630,684 B2
• Time in Patent Office: Days
• US Class Current: 455/41.2
• CPC Class Codes: G01S 13/003 Bistatic radar systems; Multistatic radar systems
• CPC Class Codes: G01S 13/325 using transmission of coded signals, e.g. P.S.K. signals
• CPC Class Codes: G01S 13/756 using a signal generator for modifying the reflectivity of the reflector G01S13/758 takes precedence
• CPC Class Codes: G01S 13/758 using a signal generator powered by the interrogation signal
• CPC Class Codes: G01S 13/878 Combination of several spaced transmitters or receivers of known location for determining the position of a transponder or a reflector G01S13/874 takes precedence
• CPC Class Codes: G06K 17/0022 arrangements or provisions for transferring data to distant stations, e.g. from a sensing device "transfer between computer elements G06F13/00 "; data-transmission H04L
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G06K 7/10079 the collision being resolved in the spatial domain, e.g. temporary shields for blindfolding the interrogator in specific directions
• CPC Class Codes: G06K 7/10316 using at least one antenna particularly designed for interrogating the wireless record carriers antennas in general H01Q1/22
• CPC Class Codes: G06K 7/10346 the antenna being of the far field type, e.g. HF types or dipoles

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.

Claims

1. A reflective communication system, comprising:

a transmitter that transmits a communication signal, comprising;

a cable having a plurality of openings in different sections of said cable; and

an antenna enclosed in said cable;

said cable having a plurality of openings in different sections so that said communication signal is transmitted at a plurality of points along said plurality of openings in said cable;

a wireless communication device that receives said communication signal from said transmitter and reflectively modulates said communication signal with a data signal having a second modulation to form a reflected data signal; and

a receiver that receives said reflected data signal.

2. The system of claim 1, wherein said receiver is adapted to remove said second modulation from said data signal to form data.

3. The system of claim 1, wherein said receiver further comprises a mixer that mixes said communication signal with said reflected data signal to remove said first modulation from said reflected data signal to form said data signal.

4. The system of claim 3, wherein said receiver further comprises a demodulator that demodulates said second modulation from said data signal to form data.

5. The system of claim 1, wherein said receiver determines the approximate location of said wireless communication device that reflected said reflected data signal by determining the delay in said reflected data signal.

6. The system of claim 1, wherein said plurality of openings each have a conductive sleeve that opens and closes to open and close said openings to control whether said communication signal radiates out of said openings.

12. The system of claim 1, wherein the communication signal transmitted at the plurality of points along the plurality of openings in the cable arrives at the receiver at a different time for each of the plurality of openings in the cable.

13. The system of claim 12, wherein the receiver is adapted to determine which one of a plurality of wireless communication devices formed the reflected data signal based on the different time for each of the plurality of openings in the cable.

7. A method of reflectively communicating a data signal from a wireless communication device using a communication signal from a transmitter as a communication medium, comprising the steps of:

transmitting communication signals having a first modulation through a plurality of openings in a cable to a plurality of reflectors;

receiving said communication signals;

reflectively modulating said communication signals with data signals having a second modulation to form reflected data signals; and

receiving said reflected data signals at a receiver.

8. The method of claim 7, further comprising removing said second modulation from said data signal to form data.

9. The method of claim 7, further comprising mixing said communication signal with said reflected data signal to remove said first modulation from said reflected data signal to form said data signal.

10. The system of claim 9, further comprising demodulating said second modulation from said data signal to form data.

11. The method of claim 7, further comprising determining the approximate location of said wireless communication device that reflected said reflected data signal by determining the delay in said reflected data signal.

14. The method of claim 7, wherein the communication signal transmitted at the plurality of points along the plurality of openings in the cable arrives at the receiver at a different time for each of the plurality of openings in the cable.

15. The method of claim 14, further comprising determining which one of a plurality of wireless communication devices formed the reflected data signal based on the different time for each of the plurality of openings in the cable.

16. A transmitter for transmitting a communication signal, the transmitter comprising:

a cable having a plurality of openings in different sections of said cable, so that said communication signal is transmitted at a plurality of points along said plurality of openings in said cable; and

an antenna enclosed in said cable.

17. The transmitter of claim 16, wherein said plurality of openings have a conductive sleeve configured to open and close said openings to control whether said communication signal radiates out of said openings.