Methods and apparatus for analyzing signal conditions affecting operation of an RFID communication device

• US 8,207,826 B2
• Filed: 10/03/2006
• Issued: 06/26/2012
• Est. Priority Date: 10/03/2006
• Status: Active Grant

• Current Assignee: NCR Voyix Corporation
• Original Assignee: NCR Corporation
• Inventors: Crooks, John Frederick, Adamec, Andrew Jeremy
• Primary Examiner(s): Wu, Daniel
• Assistant Examiner(s): POINT, RUFUS C
• Application Number:
  US11/538,299
• Publication Number:
  US 20080088416A1
• Time in Patent Office: 2,093 Days
• Field of Search: 340/10.1, 340/10.4, 340/10.41, 340/10.42, 340/825.71, 340/572.1, 340/517, 340/518, 340/540, 340/522, 340/539.31, 340/572.3, 340/572.4, 340/13.26, 340/10.3, 455/73
• US Class Current: 340/10.3
• 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

Abstract

Systems and techniques for generating data showing a signal environment experienced by a radio frequency identification (RFID) communication device. A transceiver within the communication device sweeps through a frequency range of interest in order to receive signals within the frequency range. Depending on the nature of the signals of interest, the signals detected may be reflected signals generated in response to a carrier signal produced by the communication device, or active signals produced by active sources. Baseband analysis is performed in order to detect and identify reflective signals, and spectrum analysis is performed in order to detect and identify active signal sources.

Claims

1. A radio frequency identification (RFID) reader, comprising:

a transmitter for transmitting a carrier signal to an RFID device at a relatively high carrier frequency range of 900 MHz or above;

a receiver for receiving electromagnetic signals present in an environment in which the reader is operating, including a return signal from an RFID device being read by the RFID reader; and

a processor operative to collect signal data providing information relating to the signals received by the receiver, the processor being operative to identify signal data representing the return signal from the RFID device and process the data to identify the RFID device, the processor being further operative to collect signal data representing the return signal and other signal data providing information relating to additional signals and electromagnetic phenomena present in the environment experienced by the reader, the data being collected including data relating to signals and electromagnetic phenomena interfering with the carrier signal and data relating to signals and electromagnetic phenomena interfering with the return signal, the processor being further operative to perform both baseband and spectrum analysis on the collected signal data in order to show characteristics of signals present in the environment experienced by the reader and tending to interfere with reading of RFID devices by the RFID reader.

2. The reader of claim 1, wherein the receiver is operative to receive a reflected carrier signal imposing information on the carrier signal.

3. The reader of claim 2, further comprising a downconversion unit to downconvert the signals so as to generate a lower frequency signal in a baseband frequency range around 64 kHz representing modulated information imposed on the carrier signal in order to generate the reflected carrier signal.

4. The reader of claim 3, further comprising an analog to digital converter for receiving signal information from the downconversion unit and converting the signal data to a downconverted digital signal for use by the processor.

5. The reader of claim 4, wherein the processor is operative to collect the downconverted digital signal and make the downconverted digital signal available for analysis to identify passive interference experienced by the reader.

6. The reader of claim 4, wherein the processor is operative to direct the transmitter to transmit the carrier signal so that the carrier signal sweeps through frequencies in a frequency range specified so as to produce reflected carrier signals providing desired information relating to passive interference experienced by the reader.

7. The reader of claim 1, wherein the receiver is able to receive active signals transmitted by active sources and wherein the processor is operative to collect the signals transmitted by active sources and make them available for analysis.

8. The reader of claim 7, further comprising a power detector receiving the output of the receiver in order to determine signal power of active signals received by the receiver.

9. The reader of claim 8, further comprising a second analog to digital converter for receiving a power detector output from the power detector and converting the power detector output to digital format for use by the processor.

10. The reader of claim 9, wherein the processor is operative to direct the receiver to conduct a relatively rapid sweep through a predefined frequency range.

11. The reader of claim 10, wherein the processor is operative to analyze the signal information received across the predefined frequency range in order to create a profile of active sources generating the signals.

12. A server for receiving information from a radio frequency identification (RFID) reader, comprising:

an interface for receiving signal data relating to radio frequency signals in a relatively high carrier frequency range of 900 mHz or above and present in an environment in which the reader is operating where the signal data comprises return signal data from an RFID device being read by the reader and other signal data related to additional signals not returned from an RFID device being read by the reader and electromagnetic phenomena not related to the RFID device being read by the reader but present in the environment experienced by the reader and tending to interfere with a carrier signal transmitted by the reader and return signals from RFID devices being read by the reader; and

a processor for performing of baseband and spectrum analysis on the signal data so as to provide information showing a signal environment experienced by the reader including sources of interference and the nature of the interference produced by the sources.

13. The server of claim 12, wherein the signal data received is processed signal data and wherein the processor is operative to manage the processed signal data for storage, display and analysis.

14. The server of claim 12, wherein the signal data received is raw signal data and wherein the processor is operative to perform processing on the raw signal data.

15. The server of claim 14, wherein the processor is operative to perform a fast Fourier transform operation on the raw signal data.

16. A method of signal analysis, comprising the steps of:

receiving signals experienced by a radio frequency identification (RFID) reader having a relatively high carrier frequency range of 900 mHz or above;

processing the signals to detect and identify return signals produced in response to an interrogation by the RFID reader and signals and electromagnetic phenomena tending to interfere with transmission of carrier signals by the RFID reader and reception and processing of the return signals; and

further processing the signals and electronic phenomena to generate signal data related thereto and to analyze the signal data using baseband and spectrum analysis to provide signal information showing the signal environment experienced by the reader including sources of interference and the nature of the interference produced by the sources.

17. The method of claim 16, wherein receiving of the signals includes receiving passive signals representing reflections of a carrier signal by an electronic shelf label communicating in a 2.4 GHz carrier frequency range.

18. The method of claim 17, wherein processing of the signals includes generating signal information for display, storage and analysis.

19. The method of claim 18, wherein processing of the signals includes performing a fast Fourier transform on digitized signal data reflecting a digitization of signals received at a receiver used by the reader.

20. The method of claim 16, wherein receiving of the signals further comprises receiving active signals transmitted by active sources.

21. The method of claim 16, wherein receiving of the signals further includes rapid detection of signals across a predefined frequency range.

22. The method of claim 21, wherein rapid detection of the signals across a predefined frequency range includes rapid successive examination of narrow frequency bands within the frequency range.