Optimized operation of a dense reader system

• US 20070139163A1
• Filed: 12/21/2005
• Published: 06/21/2007
• Est. Priority Date: 12/21/2005
• Status: Active Grant

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Arneson, Michael, Powell, Kevin, Bandy, William
• Granted Patent: US 7,969,282 B2
• Time in Patent Office: Days
• US Class Current: 340/10.200
• CPC Class Codes: G06K 7/10356 using a plurality of antennas, e.g. configurations including means to resolve interference between the plurality of antennas
• CPC Class Codes: G06K 7/10475 arrangements to facilitate interaction with further interrogation devices, e.g. such that at least two interrogation devices may function and cooperate in a network of such devices
• CPC Class Codes: H04W 8/26 Network addressing or numbering for mobility support
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks
• CPC Class Codes: H04W 88/02 Terminal devices

Abstract

Methods, systems and apparatuses for RFID readers forming a reader network are described. In an aspect of the present invention, a plurality of RFID readers are configured to interrogate tags. Furthermore, the readers are configured to communicate with one another. Each of the readers include a ID number which identifies that particular reader within a reader network during communications. Each reader includes a network interface module and an optimization module to receive and process statistical data obtained from other readers in the network. Aspects of the present invention include a ‘primary/secondary’ reader network configuration, as well as a ‘distributed elements’ reader network configuration. A set of operational rules for the environment is indicated, and tag interrogations are optimized according to the rules. Readers may communicate according to a “Listen Before Talk” (LBT) protocol to avoid undesirable interference. Individual readers are capable of dynamically establishing and joining a network, and leaving the network in a self-configured and semi-autonomous or autonomous manner.

Claims

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

a plurality of readers that form a network, wherein each reader of the plurality of readers comprises;

(a) at least one antenna;

(b) a tag communications module coupled to the at least one antenna and configured to interrogate tags within a communication range of the reader;

(c) an identification (ID) number that identifies the reader;

(d) a reader network interface module coupled to the at least one antenna and configured to communicate with readers of the network;

(e) a memory, wherein the memory stores at least one set of local reader network rules.

2. The system of claim 1, wherein each reader of the plurality of readers further comprises:

an optimization module that uses logic to optimize interrogations of tags by the reader in the reader network.

3. The system of claim 1, further comprising:

a population of RFID tags, wherein each tag of the population is in communication range of at least one of the readers.

4. The system of claim 1, wherein a first reader of the plurality of readers is configured to transmit information regarding a tag within a communication range of the first reader to a second reader of the plurality of readers.

5. The system of claim 4, wherein the first reader and the second reader communicate with the at least one common tag according to one of the following communication protocols:

Gen 2, Class 0, or Class 1.

6. The system of claim 1, wherein the plurality of readers comprises a primary reader.

7. The system of claim 6, wherein the primary reader is a first reader to enter the network.

8. The system of claim 6, wherein the plurality of readers other than the primary reader each receives a set of local network rules from the primary reader.

9. The system of claim 6, wherein the primary reader instructs each reader of the plurality of readers to use a particular set of local network rules stored in the memory.

10. The system of claim 1, wherein a reader of the plurality of readers listens for communications before transmitting a communication signal.

11. The system of claim 1, wherein each reader uses a selected rule set of the at least one set of local network rules to regulate communications with other readers of the network.

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

(a) at least one antenna;

(b) a tag communications module coupled to the at least one antenna and configured to interrogate tags;

(c) an identification number (ID) that identifies the reader in a reader network;

(d) a reader network interface module coupled to the at least one antenna configured to communicate with readers in the reader network; and

(e) a memory, wherein the memory stores at least one set of local network rules.

13. The device of claim 12, wherein the reader further comprises:

an optimization module that uses logic to optimize interrogations of tags by the reader in the reader network.

14. The device of claim 12, wherein the device is configured to operate as primary reader.

15. A method of communication for a reader in a reader network, comprising:

(a) transmitting a request to the reader network to interrogate a tag, the request including an identification number for the reader;

(b) receiving a response from the reader network; and

(c) interrogating the tag.

16. The method of claim 15, further comprising:

(d) prior to step (c), listening to communications between at least one reader of the reader network and at least one tag; and

(e) determining whether the communications would interfere with a tag interrogation.

17. The method of claim 15, wherein step (c) comprises:

interrogating the tag if it is determined in step (e) of claim 16, that the communications would not interfere.

18. The method of claim 16, further comprising:

(d) entering the reader network.

19. The method of claim 18, wherein step (d) further comprises:

(1) determining whether a reader network exists;

(2) initiating the reader network if the reader network does not exist; and

(3) providing the identification number for the reader to the reader network.

20. The method of claim 15, further comprising:

(d) receiving a set of rules dictating interaction of the reader with the reader network.

21. The method of claim 15, further comprising:

(d) exiting the reader network.

22. The method of claim 21, wherein step (d) comprises:

(1) transmitting a request to exit the reader network;

(2) receiving an acknowledgement and approval of the exit request from the reader network; and

(3) exiting the reader network.

23. The method of claim 15, further comprising:

(d) receiving information in the response regarding requests to interrogate the tag by other readers of the reader network; and

(e) using the information to optimize an interrogation of the tag in step (c).