Reconstructing RFID waveform shape for reuse in individual channel

• US 7,432,814 B2
• Filed: 04/25/2006
• Issued: 10/07/2008
• Est. Priority Date: 04/13/2004
• Status: Active Grant

• Current Assignee: Impinj, Inc.
• Original Assignee: Impinj, Inc.
• Inventors: Diorio, Christopher J., Sundstrom, Kurt E., Dietrich, Paul, Humes, Todd E.
• Primary Examiner(s): Bugg; George A
• Assistant Examiner(s): Walk; Samuel J
• Application Number:
  US11/412,171
• Publication Number:
  US 20060261954A1
• Time in Patent Office: 896 Days
• Field of Search: 340/10.1, 340 103- 104, 340/572.1, 340/572.4
• US Class Current: 340/572.4
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• 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, software, devices, and methods are described for an RFID reader system to communicate with RFID tags. RF energy detected in conjunction with using a selected channel is detected and used to adjust a waveform shaping parameter. The waveform shaping parameter can be additionally stored, and then reconstructed for later use in the same channel. Reconstruction can optionally be also from derived channel performance data. RF waves can be transmitted from the reader to the RFID tags and RF waves can be backscattered from the RFID tags. At least some of the RF waves transmitted to or backscattered from the RFID tags have a waveform with a shape according to the reconstructed waveform shaping parameter.

Claims

1. An RFID reader system comprising:

an antenna; and

an operational processing block coupled to the antenna and operable to

select a first one of a plurality of communication channels;

adjust an own waveform shaping parameter responsive to RF energy detected in conjunction with using the selected channel;

cause the antenna to transmit to RFID tags first RF waves in the selected channel such that second RF waves are backscattered from the RFID tags in response to the first RF waves, in which at least some of one of the first RF waves and the second RF waves have a waveform with a shape according to the adjusted own waveform shaping parameter;

store a first channel parameter value associated with the adjusted waveform shaping parameter;

then select a second one of the channels;

operate in the selected second channel by transmitting to the RFID tags third RF waves in the second channel and receiving fourth RF waves backscattered from the RFID tags in response to the third RF waves;

readjust the own waveform shaping parameter concurrently with operating in the selected second channel;

reselect the first channel and reconstruct the own waveform shaping parameter from the stored first channel parameter value; and

then transmit to the RFID tags fifth RF waves in the reselected first channel and receive sixth RF waves backscattered from the RFID tags in response to the fifth RF waves, at least some of the fifth and the sixth RF waves having a waveform with a shape according to the reconstructed own waveform shaping parameter.

2. The system of claim 1, in which the own waveform shaping parameter controls a choice of a modulation format.

3. The system of claim 1, in which

the own waveform shaping parameter controls a choice of a preamble.

4. The system of claim 1, in which

the own waveform shaping parameter controls a choice of a signal encoding.

5. The system of claim 4, in which

the own waveform shaping parameter communicates one or a combination:

of a data rate, a mode, attributes of a calibration pulse, a rise time, a fall time, a pulse shaping, a pulse width, and a preamble.

6. The system of claim 1, in which

the own waveform shaping parameter represents a protocol parameter for an RFID system according to a communications protocol.

7. The system of claim 6, in which

the protocol parameter includes a command for a tag to change its state machine.

8. The system of claim 6, in which

the protocol parameter includes a command for a tag to respond in a certain manner according to the protocol.

9. The system of claim 1, in which

the first channel parameter value includes at least one of a designator for the first channel, a designator for a parameter of the first channel, settings for a parameter of the first channel, and last tried settings for a parameter of the first channel.

10. The system of claim 1, in which the processing block is further operable to:

assemble first channel usage data from at least one of the detected RF energy, the first RF waves and the second RF waves, and

in which the own waveform shaping parameter is reconstructed also according to the assembled first channel usage data.

11. The system of claim 10, in which

the first channel usage data includes at least one of a designator for the first channel, a designator for a parameter of the first channel, measurements about the detected RF energy, measurements about the second RF waves, settings for a parameter of the first channel, last tried settings for a parameter of the first channel, performance statistics for a parameter of the first channel, and a preference rank for the first channel.

12. The system of claim 10, in which the processing block is further operable to:

store the assembled first channel performance data, and

recall the stored first channel usage data to reconstruct the waveform shaping parameter.

13. The system of claim 10, in which the processing block is further operable to:

associate the first channel usage data with an event; and

discount the usage data according to an age of the event, when reconstructing the waveform shaping parameter.

14. The system of claim 10, in which the processing block is further operable to:

assemble second channel usage data from at least one of the third RF waves and the fourth RF waves;

store the assembled second channel usage data; and

recall the stored second channel usage data.

15. An article comprising:

a storage medium, the storage medium having instructions stored thereon, in which when the instructions are executed by at least one component of an RFID reader system that is operable to communicate with RFID tags, they result in;

selecting a first one of a plurality of communication channels;

detecting RF energy encountered in conjunction with using the selected channel;

adjusting an own waveform shaping parameter responsive to the detected RF energy;

transmitting to the RFID tags first RF waves in the selected channel and receiving second RF waves backscattered from the RFID tags in response to the first RF waves, at least some of one of the first RF waves and the second RF waves having a waveform with a shape according to the adjusted own waveform shaping parameter;

storing a first channel parameter value associated with the adjusted waveform shaping parameter;

then selecting a second one of the channels;

operating in the selected second channel by transmitting to the RFID tags third RF waves in the second channel and receiving fourth RF waves backscattered from the RFID tags in response to the third RF waves;

readjusting the own waveform shaping parameter concurrently with operating in the selected second channel;

reselecting the first channel and reconstructing the own waveform shaping parameter from the stored first channel parameter value; and

then transmitting to the RFID tags fifth RF waves in the reselected first channel and receiving sixth RF waves backscattered from the RFID tags in response to the fifth RF waves, at least some of one of the fifth and the sixth RF waves having a waveform with a shape according to the reconstructed own waveform shaping parameter.

16. The article of claim 15, in which

the own waveform shaping parameter controls a choice of a modulation format.

17. The article of claim 15, in which

the own waveform shaping parameter controls a choice of a preamble.

18. The article of claim 15, in which

the own waveform shaping parameter controls a choice of a signal encoding.

19. The article of claim 18, in which

the own waveform shaping parameter communicates one or a combination:

of a data rate, a mode, attributes of a calibration pulse, a rise time, a fall time, a pulse shaping, a pulse width, and a preamble.

20. The article of claim 15, in which

the own waveform shaping parameter represents a protocol parameter for an RFID system according to a communications protocol.

21. The article of claim 20, in which

the protocol parameter includes a command for a tag to change its state machine.

22. The article of claim 20, in which

the protocol parameter includes a command for a tag to respond in a certain manner according to the protocol.

23. The article of claim 15, in which

the first channel parameter value includes at least one of a designator for the first channel, a designator for a parameter of the first channel, settings for a parameter of the first channel, and last tried settings for a parameter of the first channel.

24. The article of claim 15, in which when the instructions are executed, they further result in:

assembling first channel usage data from at least one of the detected RF energy, the first RF waves and the second RF waves, and

in which the own waveform shaping parameter is reconstructed also according to the assembled first channel usage data.

25. The article of claim 24, in which

the first channel usage data includes at least one of a designator for the first channel, a designator for a parameter of the first channel, measurements about the detected RF energy, measurements about the second RF waves, settings for a parameter of the first channel, last tried settings for a parameter of the first channel, performance statistics for a parameter of the first channel, and a preference rank for the first channel.

26. The article of claim 24, in which when the instructions are executed, they further result in:

storing the assembled first channel usage data, and

recalling the stored first channel usage data to reconstruct the waveform shaping parameter.

27. The article of claim 24, in which when the instructions are executed, they further result in:

associating the first channel usage data with an event; and

discounting the usage data according to an age of the event, when reconstructing the waveform shaping parameter.

28. The article of claim 24, in which when the instructions are executed, they further result in:

assembling second channel usage data from at least one of the third RF waves and the fourth RF waves;

storing the assembled second channel usage data; and

recalling the stored second channel usage data.

29. A method for an RFID reader system to communicate with RFID tags, comprising:

selecting a first one of a plurality of communication channels;

detecting RF energy encountered in conjunction with using the selected channel;

adjusting an own waveform shaping parameter responsive to the detected RF energy;

transmitting to the RFID tags first RF waves in the selected channel and receiving second RF waves backscattered from the RFID tags in response to the first RF waves, at least some of one of the first RF waves and the second RF waves having a waveform with a shape according to the adjusted own waveform shaping parameter;

storing a first channel parameter value associated with the adjusted waveform shaping parameter;

then selecting a second one of the channels;

operating in the selected second channel by transmitting to the RFID tags third RF waves in the second channel and receiving fourth RF waves backscattered from the RFID tags in response to the third RF waves;

readjusting the own waveform shaping parameter concurrently with operating in the selected second channel;

reselecting the first channel and reconstructing the own waveform shaping parameter from the stored first channel parameter value; and

then transmitting to the RFID tags fifth RF waves in the reselected first channel and receiving sixth RF waves backscattered from the RFID tags in response to the fifth RF waves, at least some of one of the fifth and the sixth RF waves having a waveform with a shape according to the reconstructed own waveform shaping parameter.

30. The method of claim 29, in which

the own waveform shaping parameter controls a choice of a modulation format.

31. The method of claim 29, in which

the own waveform shaping parameter controls a choice of a preamble.

32. The method of claim 29, in which

the own waveform shaping parameter controls a choice of a signal encoding.

33. The method of claim 32, in which

the own waveform shaping parameter communicates one or a combination:

of a data rate, a mode, attributes of a calibration pulse, a rise time, a fall time, a pulse shaping, a pulse width, and a preamble.

34. The method of claim 29, in which

the own waveform shaping parameter represents a protocol parameter for an RFID system according to a communications protocol.

35. The method of claim 34, in which

the protocol parameter includes a command for a tag to change its state machine.

36. The method of claim 34, in which

the protocol parameter includes a command for a tag to respond in a certain manner according to the protocol.

37. The method of claim 29, in which

the first channel parameter value includes at least one of a designator for the first channel, a designator for a parameter of the first channel, settings for a parameter of the first channel, and last tried settings for a parameter of the first channel.

38. The method of claim 29, further comprising:

assembling first channel usage data from at least one of the detected RF energy, the first RF waves and the second RF waves, and

in which the own waveform shaping parameter is reconstructed also according to the assembled first channel usage data.

39. The method of claim 38, in which

the first channel usage data includes at least one of a designator for the first channel, a designator for a parameter of the first channel, measurements about the detected RF energy, measurements about the second RF waves, settings for a parameter of the first channel, last tried settings for a parameter of the first channel, performance statistics for a parameter of the first channel, and a preference rank for the first channel.

40. The method of claim 38, further comprising:

storing the assembled first channel usage data, and

recalling the stored first channel usage data to reconstruct the waveform shaping parameter.

41. The method of claim 38, further comprising:

associating the first channel usage data with an event; and

discounting the usage data according to an age of the event, when reconstructing the waveform shaping parameter.

42. The method of claim 38, further comprising:

assembling second channel usage data from at least one of the third RF waves and the fourth RF waves;

storing the assembled second channel usage data; and

recalling the stored second channel usage data.