RFID READERS CO-EXISTING WITH OTHER ISM-BAND DEVICES

• US 20080266098A1
• Filed: 03/26/2008
• Published: 10/30/2008
• Est. Priority Date: 04/18/2007
• Status: Abandoned Application

• Current Assignee: Impinj, Inc.
• Original Assignee: Impinj, Inc.
• Inventors: Diorio, Christopher J., Khwaja, Omar, Aiouaz, Ali, Esterberg, Aanand, Ord, David, Thomas, Mike, Jain, Harsh
• Application Number:
  US12/056,120
• Publication Number:
  US 20080266098A1
• Time in Patent Office: Days
• US Class Current: 340/572.1
• CPC Class Codes: H04W 52/16 Deriving transmission power values from another channel
• CPC Class Codes: H04W 52/245 taking into account received signal strength
• CPC Class Codes: H04W 52/246 where the output power of a terminal is based on a path parameter calculated in said terminal
• CPC Class Codes: H04W 52/247 where the output power of a terminal is based on a path parameter sent by another terminal

Abstract

Radio Frequency IDentification (RFID) reader system, software, and methods are provided, such that an operational processing block for the RFID reader to communicate with an RFID tag uses a RF spectrum portion subdivided into a set of channels. The communication takes place in the presence of a foreign device that uses a subset of first channels of the RF spectrum and does not use a subset of second channels of the spectrum. The methods cause a radiating power directed towards the tag to be reduced and a radiating dwell time to be changed. This is to assure that co-existing systems can operate without compromising their functionality and operational quality. In some embodiments, the radiating power is reduced to zero.

Claims

1. An operational processing block for a Radio Frequency Identification (RFID) reader to communicate with an RFID tag using a frequency spectrum portion subdivided into a set of channels, in which the communication takes place in the presence of a foreign device that uses a subset of first channels of the spectrum and does not use a subset of second channels of the spectrum, comprising:

a component for radiating towards the tag with at least 10% less power in some of the first channels than in some of the second channels.

2. The operational processing block of claim 1, in which

an average radiated power in the first channels is less than an average radiated power in the second channels.

3. The operational processing block of claim 1, in which

there is zero power radiated in some of the first channels.

4. The operational processing block of claim 1, in which

there is non-zero power radiated in some of the first channels.

5. The operational processing block of claim 1, in which

there is approximately zero dBm power in some of the first channels.

6. The operational processing block of claim 1, in which

the power in some of the first channels is determined from a measured signal characteristic of the foreign device, the characteristic being one of a strength and a modulation of the measured signal.

7. The operational processing block of claim 1, in which

the power in some of the first channels is determined from a feedback from the foreign device.

8. The operational processing block of claim 1, in which

the power in some of the first channels is less by a predetermined amount than the power in some of the second channels.

9. The operational processing block of claim 1, in which

the number of first channels is no more than sixteen.

10. The operational processing block of claim 1, further comprising:

a component for adjusting a configuration of the RFID reader for the foreign device.

11. The operational processing block of claim 10, in which

adjusting is done using a pre-configuring setting.

12. The operational processing block of claim 10, in which

adjusting is performed based on results of occasional checking for a foreign device.

13. The operational processing block of claim 12, in which

the checking is performed by communicating with another reader over a wire and learning about the first channels.

14. The operational processing block of claim 12, in which

the checking is performed by analyzing a received RF wave energy from the foreign device.

15. The operational processing block of claim 12, in which

checking is performed by analyzing a received RF wave signal modulation from the foreign device.

16. The operational processing block of claim 12, in which

the checking includes:

transmitting a unique interrogation signal to a foreign device;

determining a presence of the foreign device from a received response; and

determining the first channels being used by the foreign device.

17. The operational processing block of claim 1, in which

the first channels include central channels and marginal channels, and

the foreign device is more susceptible to interference in the central channels than in the marginal channels.

18. The operational processing block of claim 17, in which

radiating in some of the central channels takes place with less power than in some of the marginal channels.

19. The operational processing block of claim 17, in which

radiating takes place pursuant to a channel hopping sequence, according to which radiating in each one of the first channels is immediately preceded and immediately followed by radiating in one of the second channels during a complete pass, the pass being complete when all the channels have been dwelled in at least once.

20. The operational processing block of claim 1, in which

radiating is such that a dwell time in some of the first channels is briefer than a dwell time in some of the second channels.

21. The operational processing block of claim 20, in which

a total dwell time in each of the first channels is approximately the same as the dwell time in each of the second channels during a complete pass, the pass being complete when all the channels have been dwelled in at least once.

22. The operational processing block of claim 20, in which

the dwell times for the first channels depend on a comparison of a number of the first channels to a number of the second channels.

23. The operational processing block of claim 20, in which

the dwell times for the second channels are independent from a number of the first channels.

24. An article comprising:

a storage medium, the storage medium having instructions stored thereon, in which when the instructions are executed by at least a Radio Frequency Identification (RFID) reader system component to communicate with an RFID tag using a frequency spectrum portion subdivided into a set of channels, in which the communication takes place in the presence of a foreign device that uses a subset of first channels of the spectrum and does not use a subset of second channels of the spectrum, the instructions result in actions, comprising;

radiating towards the tag with at least 10% less power in some of the first channels than in some of the second channels.

25. A method for a Radio Frequency Identification (RFID) reader system component to communicate with an RFID tag using a frequency spectrum portion subdivided into a set of channels, in which the communication takes place in the presence of a foreign device that uses a subset of first channels of the spectrum and does not use a subset of second channels of the spectrum, comprising:

radiating towards the tag with at least 10% less power in some of the first channels than in some of the second channels.