SOFTWARE-DEFINED MULTI-MODE RFID READ DEVICES

• US 20110187509A1
• Filed: 02/04/2010
• Published: 08/04/2011
• Est. Priority Date: 02/04/2010
• Status: Active Grant

• Current Assignee: Carefusion 303 Incorporated (Becton, Dickinson & Co)
• Original Assignee: Carefusion 303 Incorporated (Becton, Dickinson & Co)
• Inventors: Ross, Graham, Raptis, Mark
• Granted Patent: US 9,342,716 B2
• Time in Patent Office: Days
• US Class Current: 340/10.3
• CPC Class Codes: G06K 7/10069 the collision being resolved in the frequency domain, e.g. by hopping from one frequency to the other frequency hopping or spread spectrum techniques H04B7/00
• CPC Class Codes: G06K 7/10128 the step consisting of detection of the presence of one or more record carriers in the vicinity of the interrogation device
• CPC Class Codes: G06K 7/10356 using a plurality of antennas, e.g. configurations including means to resolve interference between the plurality of antennas

Abstract

Devices and methods for reading multiple types of RFID tags having different frequencies and/or encoding schemes are disclosed. One or more search signals covering a plurality of RFID bands are transmitted. A presence indication of an RFID tag in one of the plurality of RFID bands is detected. An interrogating signal having a carrier frequency tuned to a frequency at which the presence indication is detected is transmitted. A tag response signal comprising tag information associated with the RFID tag is received. A digital response signal based on the tag response signal is digital signal processed to obtain the tag information.

Claims

1. A method of reading a radio frequency identification (RFID) tag, the method comprising:

transmitting a search signal covering a plurality of RFID bands;

detecting a presence indication of an RFID tag in one of the plurality of RFID hands; and

reading the RFID tag.

2. The method of claim 1, wherein the search signal includes a collection of search signals for the plurality of RFID bands.

3. The method of claim 2, wherein transmitting a search signal for a particular RFID band comprises sweeping a frequency substantially over an entire bandwidth of the RFID band.

4. The method of claim 2, wherein transmitting a search signal for a particular RFID hand comprises transmitting a single search signal having a spectrum that substantially cover an entire bandwidth of the particular RFID band.

5. The method of claim 1, wherein the presence indication comprises a drop in the strength of a reflected signal.

6. The method of claim 1, wherein reading the RFID tag comprises:

generating a modulated interrogating signal having a carrier frequency set to a target frequency at which the tag presence indication is detected;

receiving a tag response signal from an MID tag, the tag response signal comprising tag information associated with the RFID tag;

producing a digital response signal based on the tag response signal; and

digital signal processing the digital response signal to obtain the tag information, wherein the digital signal processing comprises at least one of digital modulation, digital filtering, and digital decoding.

7. The method of claim 6, wherein generating the modulated interrogating signal comprises modulating a carrier signal oscillating at the target frequency with a modulation signal varying at a frequency lower than the target frequency.

8. The method of claim 7, wherein modulating the carrier signal is performed in a digital domain.

9. The method of claim 7, wherein modulating the carrier signal is performed in an analog domain.

10. The method of claim 6 further comprising demodulating the tag or digital response signal with a carrier signal oscillating at the target frequency.

11. The method of claim 10, wherein the demodulating is performed in a digital domain.

12. The method of claim 10, wherein the demodulating is performed in an analog domain.

13. A method of reading multiple types of RFID tags, the method comprising:

transmitting one or more search signals covering a plurality of RFID bands;

detecting a presence indication of an RFID tag in one of the plurality of RFID bands;

transmitting an interrogating signal having a carrier frequency tuned to a frequency at which the presence indication is detected;

receiving a tag response signal from the RFID tag, the tag response signal comprising tag information associated with the RFID tag; and

digital signal processing a digital response signal based on the tag response signal to obtain the tag information.

14. A radio frequency identification (RFID) device comprising:

an antenna; and

a processor configured to;

cause the antenna to transmit a search signal covering a plurality of RFID bands;

detect a presence indication of an RFID tag in one of the plurality of RFID bands, and

read the RFID tag based on a tag response signal comprising tag information associated with the RFID tag.

15. The device of claim 14, further comprising an analog-to-digital converter configured to produce a digital response signal based on the tag response signal;

wherein;

the processor is further configured to digital signal process the digital response signal to obtain the tag information, and

the digital signal processing comprises at least one of digital modulation, digital filtering, and digital decoding.

16. The device of claim 15, wherein the processor is further configured to output a signal indicative of a target frequency associated with a target frequency at which the presence indication is detected, and a digital modulation signal, the device further comprising:

a local oscillator configured to receive the signal indicative of the target frequency, and to generate a carrier signal oscillating at the target frequency;

a digital-to-analog converter configured to receive the digital modulation signal, and to generate an analog modulation signal, the analog modulation signal varying at a frequency lower than the target frequency; and

an analog modulator configured to receive the carrier signal and the analog modulation signal, and to generate a modulated interrogating signal by mixing the carrier signal with the analog modulation signal.

17. The device of claim 16, wherein the local oscillator comprises a phase-locked loop (PLL) synthesizer.

18. The device of claim 16, wherein the analog modulation signal is a quadrature-encoded signal.

19. The device of claim 16, wherein the analog modulation signal provides a frequency modulation of the carrier signal.

20. The device of claim 16, wherein the analog modulation signal provides an amplitude-modulation of the carrier signal.

21. The device of claim 16 further comprising an analog demodulator configured to receive the response signal and to demodulate the same with the carrier signal to generate an intermediate frequency (IF) response signal, wherein the IF response signal is converted into the digital response signal by the analog-to-digital converter.

22. The device of claim 15, wherein the processor is further configured to output a signal indicative of a target frequency at which the presence indication is detected, and a digital modulation signal, the device further comprising:

a local oscillator configured to receive the signal indicative of the target frequency and to generate a carrier signal oscillating at the target frequency; and

one or more electronic components configured to receive the carrier signal and the digital modulation signal, and to generate a modulated interrogating signal by amplitude-modulating the carrier signal with the digital modulation signal.

23. The device of claim 22, wherein the one or more electronic components comprise an output amplifier having a digital on/off control input configured to receive the digital modulation signal.

24. The device of claim 22, wherein the one or more electronic components comprise an output amplifier, and an analog switch connected to the output amplifier and having a digital on/off control input configured to receive the digital modulation signal.

25. The device of claim 22 further comprising an analog demodulator configured to receive the response signal, and to demodulate the same with the carrier signal to generate an intermediate frequency (IF) response signal, wherein the IF response signal is converted into the digital response signal by the analog-to-digital converter.

26. The device of claim 15, wherein the processor is further configured to output a digital interrogating signal, the device further comprising a digital-to-analog (D/A) converter configured to receive the digital interrogating signal, and to generate an analog modulated interrogating signal having its carrier frequency set at a target frequency .at which the presence indication is detected.

27. The device of claim 26 further comprising an output amplifier configured to amplify the analog modulated interrogating signal before the signal is wirelessly transmitted.

28. The device of claim 26 further comprising an input amplifier configured to receive the response signal, and to amplify the same, wherein the amplified response signal is converted into the digital response signal by the analog-to-digital converter.

29. The device of claim 14, wherein the processor is configured to be initially programmed to read a set of multiple types of RFID tags, and then subsequently reprogrammed to read a new type of RFID tag.

30. The device of claim 29, wherein the multiple types of RFID tags comprise RFID tags based on different encoding schemes.

31. The device of claim 29, wherein the multiple types of RFID tags comprise RFID tags having different RFID bands.

32. The device of claim 31, wherein the RFID bands comprise 125 kHz, 13.56 MHz, 915 MHz, and 2.4 GHz bands.

33. The device of claim 14, wherein the tag response signal comprises a signal reflected from a passive RFID tag.

34. The device of claim 14, wherein the tag response signal comprises a signal generated by an active RFID tag.

35. The device of claim 14, wherein the antenna comprises a set of transceiver antennas, each of the transceiver antennas configured to transmit and receive a signal in a different RFID band.

36. The device of claim 14, wherein the antenna comprises a single transceiver antenna having a fundamental frequency covering one of the plurality of RFID bands and one or more harmonic frequencies covering one or more remaining RFID hands.