Wireless RFID networking systems and methods

• US 8,345,653 B2
• Filed: 01/19/2012
• Issued: 01/01/2013
• Est. Priority Date: 11/07/2005
• Status: Expired due to Fees

• Current Assignee: Radiofy, LLC
• Original Assignee: Radiofy, LLC
• Inventors: Shoarinejad, Kambiz
• Primary Examiner(s): Batista, Marcos
• Application Number:
  US13/354,288
• Publication Number:
  US 20120113902A1
• Time in Patent Office: 348 Days
• Field of Search: 455/404.2, 370/338
• US Class Current: 370/338
• CPC Class Codes: G01S 19/05 providing aiding data
• CPC Class Codes: G01S 19/09 providing processing capability normally carried out by the receiver
• 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 7/10079 the collision being resolved in the spatial domain, e.g. temporary shields for blindfolding the interrogator in specific directions
• CPC Class Codes: H04W 60/00 Affiliation to network, e.g. registration; Terminating affiliation with the network, e.g. de-registration
• CPC Class Codes: H04W 76/40 for selective distribution or broadcast
• CPC Class Codes: H04W 84/22 with access to wired networks
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

Embodiments of the present invention include a wireless access point that acquires and processes radio frequency identification (RFID) information. The wireless access point may be coupled to a network of RFID readers over a wireless network. The RFID readers may read a plurality of RFID tags and transmit information to one or more readers. The readers may, in turn, transmit the RFID information to a wireless access point. The wireless access point may include a middleware layer for performing a variety of RFID data processing functions. In one embodiment, the wireless RFID reader network may be used to improve positioning of readers and tags, and may include a GPS system or position assisted GPS system at the reader and/or tag level.

Claims

1. A system for distributed tag management, the system comprising:

a plurality of tags comprising tag data;

a set of tag readers to retrieve tag data, a plurality of tag readers in the set of tag readers comprising storage to store tag data and tag positions, each tag reader in the plurality of tag readers to receive signals from one or more tags and to calculate initial tag positions based on a measurement of the received signals and a position of the tag reader; and

a set of access points, each access point to receive tag data from one or more tag readers in the set of tag readers, at least one access point in the set of access points comprising storage, the access point to (i) receive, from two tag readers in the plurality of tag readers, measurements of the received signals of a particular tag residing in an overlapping coverage area of the two tag readers, and (ii) calculate a revised position of the particular tag based on a differential calculation of the measurements received from said two tag readers.

2. The system of claim 1, wherein calculating the particular tag position by the access point is further based on a known fixed location of at least one of the two tag readers.

3. The system of claim 1, wherein the access point is further to determine positions of tag readers in a coverage area of the access point.

4. The system of claim 3, wherein determining tag reader position is performed using data received at a Global Positioning System (GPS) module in at least one tag reader.

5. The system of claim 1 further comprising a server, the server comprising storage, the access point further to send positions of the tag readers to the server to store in said server storage.

6. The system of claim 5, wherein the server is further to send the positions of the tag readers received from each access point to other access points in the set of access points.

7. The system of claim 5, wherein the server is further to receive tag data from at least one access point.

8. The system of claim 5, wherein the server is further to determine tag reader positions based on distances between a particular tag reader and at least two access points with overlapping coverage areas.

9. The system of claim 1, wherein at least one tag reader in the plurality of tag readers is to determine tag positions by using data received from a Global Positioning System (GPS) module in at least one tag.

10. The system of claim 1, wherein said calculating the revised position by the access point is performed using data received from a Global Positioning System (GPS) module in at least one of the two tag readers.

11. The system of claim 1, wherein at least one access point comprises a Global Positioning System (GPS) module to assist at least one GPS enabled tag reader to determine a position of the tag reader.

12. The system of claim 1, wherein at least one access point comprises a Global Positioning System (GPS) module to assist at least one GPS enabled tag to determine a position of the tag.

13. The system of claim 1, wherein each tag comprises one of an active backscattering circuit and a passive backscattering circuit.

14. The system of claim 1, wherein the set of tag readers and the plurality of tags are communicatively coupled through a wireless sensor network.

15. The system of claim 1, wherein the access point is further to filter tag data, wherein filtering comprises removing redundant data received from the set of tag readers.

16. The system of claim 1, wherein the tag data is stored at an application layer of the access point.

17. The system of claim 1, wherein the tag data is stored in the access point storage.

18. The system of claim 1, wherein said access point and said set of tag readers are configured in a star network configuration.

19. The system of claim 1, wherein said access point and said set of tag readers are configured in a mesh network configuration.

20. The system of claim 1, wherein said access point and said set of tag readers are configured in a hybrid network configuration, wherein a hybrid network configuration comprises modifications of star and mesh network configurations.

21. The system of claim 1, wherein tag data received from at least one tag comprises a tag position.

22. The system of claim 1, wherein the measurement of the received signals comprises measurement of at least one of a received power of the signal, angle of reception of the signal, time of arrival of the signal, and a carrier phase of the signal.

23. The system of claim 1, the access point further to (i) store the received tag data in the access point storage, (ii) receive calculated tag positions from one or more tag readers in the plurality of tag readers, (iii) store tag positions in the access point storage, (iv) determine that a position of a tag has changed, and (v) transmit the changed tag position to one or more tag readers.

24. The system of claim 23, wherein determining that a tag position has changed comprises determining that the tag has moved in or out of a coverage area of a tag reader.

25. The system of claim 1, wherein the tags are radio frequency identification (RFID) tags.

26. A method of determining tag positions in a distributed tag processing system comprising a plurality of tag readers, the method comprising:

receiving tag signals comprising tag data at two tag readers in the plurality of tag readers from a particular tag residing in an overlapping coverage area of the two tag readers;

determining an initial position of the particular tag at each tag reader based on a measurement of the tag signals received at the tag reader and a position of the tag reader;

storing the tag data and the tag position at each of the two tag readers;

sending the measurement of the tag signals from each of the two tag readers to an access point; and

determining a revised position of the particular tag at the access point based on a differential calculation of the measurements of the tag signals received from the two tag readers.

27. The method of claim 26, wherein determining the initial position of the particular tag by at least one of the two tag readers further comprises:

receiving a plurality of signals from the particular tag at the reader;

measuring a value of a parameter for each signal of the plurality of received signals; and

calculating an improved value of the parameter based on a difference of the values of the parameter measured for each signal in the plurality of received signals.

28. The method of claim 27, wherein the parameter comprises at least one of a received power of the signal, an angle of reception of the signal, a time of arrival of the signal, and a carrier phase of the signal.

29. The method of claim 26 further comprising:

at the access point, determining that a position of the particular tag has changed when the particular tag moves in or out of a coverage area of a tag reader; and

transmitting the changed position to one or more tag readers.

30. The method of claim 26, wherein the tag is a radio frequency identification (RFID) tag.