Autonomous tuning method to improve radio frequency performance

• US 9,767,328 B2
• Filed: 03/14/2014
• Issued: 09/19/2017
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Assa Abloy AB
• Original Assignee: Assa Abloy AB
• Inventors: Padilla, Toby Mark, Milbrandt, Ryan, Holloway, Bryan Stephen, Edwards, Geoffrey
• Primary Examiner(s): Alizada, Omeed
• Application Number:
  US14/212,846
• Publication Number:
  US 20140266627A1
• Time in Patent Office: 1,285 Days
• 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
• CPC Class Codes: G06K 7/10138 the step consisting of determining the type of record carrier, e.g. to determine if the record carrier is an RFID tag of the long or short range type, or to determine the preferred communication protocol of the RFID tag
• CPC Class Codes: G06K 7/10148 the step consisting of dynamically tuning the resonant circuit of the interrogation device that is emitting the interrogation signal, e.g. for impedance matching inside of the interrogation device for tuning related to loop aerials in general H01Q7/00
• CPC Class Codes: G06K 7/10198 setting parameters for the interrogator, e.g. programming parameters and operating modes

Abstract

Methods and systems are provided for an RFID system that can be tuned dynamically and/or in real-time during a coupling event between a reader and a transponder. The reader can comprise an antenna assembly, a signal driver, and a controller. The antenna assembly may include a tuning circuit and an antenna coupled to the tuning circuit. The tuning circuit can include registers that may be set to adjust one or more characteristics of the reader. A controller is coupled to the antenna assembly to determine characteristics of the received signal and to set hardware or firmware functions that improve the coupling of the reader and transponder and/or improve the reception of the signal(s) from the transponder.

Claims

1. A method of improving performance of a reader in a radio frequency identification (RFID) system, comprising:

a reader antenna assembly, of the reader, receiving an initial detection of a transponder;

the reader receiving initial information about the transponder;

based on the initial information, determining a best configuration for the reader antenna assembly while the transponder is at least first distance away from the reader;

based on the best configuration and while the transponder is at least the first distance away from the reader, setting one or more registers that change at least one parameter associated with operation of the reader antenna assembly, wherein the one or more registers are integral to a tuning circuit of the reader; and

after the transponder is less than the first distance away from the reader, switching at least one setting of the one or more registers.

2. The method of claim 1, further comprising:

monitoring a signal associated with the transponder; and

based on the monitored signal, determining a second best configuration of the reader antenna assembly.

3. The method of claim 2, further comprising, based on the second best configuration, adjusting the one or more registers to change the at least one parameter associated with operation of the reader antenna assembly.

4. The method of claim 3, further comprising reading a credential provided by the transponder.

5. The method of claim 4, further comprising storing the settings of the one or more registers along with a time at which the one or more registers were set.

6. The method of claim 5, wherein the initial information includes one of an identifier for the transponder or an indication of a type of transponder.

7. The method of claim 6, further comprising:

based on one of the identifier for the transponder or the indication of the type of transponder, retrieving stored settings determined during a previous connection with the transponder; and

providing the stored settings as the best configuration.

8. The method of claim 5, wherein the initial information includes one or more environmental conditions encountered when detecting the transponder.

9. The method of claim 6, further comprising:

based on the one or more environmental conditions, retrieving second stored settings determined during a second previous connection with a second transponder, wherein the second previous connection had one or more similar environmental conditions as the one or more environmental conditions; and

providing the second stored settings as the best configuration.

10. The method of claim 1, wherein the at least one parameter is associated with one of a gain, a filter level, a threshold level, capacitance, or an impedance.

11. A receiver, comprising:

a reader antenna assembly comprising;

an antenna;

a tuning circuit in communication with the antenna, the tuning circuit operable to change at least one parameter associated with operation of the reader antenna assembly, the tuning circuit comprising;

one or more registers, when set, operable to change the at least one parameter;

an exciter/reader circuit in communication with the reader antenna assembly, the exciter/reader circuit comprising;

a transponder signal receiver circuit comprising;

a monitor circuit operable to;

receive the initial detection;

receive initial information about the transponder;

an adjuster operable to;

based on the initial information, determine a best configuration for the reader antenna assembly while the transponder is at least a first distance away from the reader antenna assembly;

a controller in communication with the reader antenna assembly and the exciter/reader circuit, the controller operable to;

receive the best configuration for the reader antenna assembly while the transponder is at least the first distance away from the reader assembly;

based on the best configuration, setting the one or more registers of the tuning circuit as long as the transponder is at least the first distance away; and

after the transponder is less than the first distance away from the reader antenna assembly, switching at least one setting of the one or more registers of the tuning circuit.

12. The receiver of claim 11, wherein the monitor circuit is further operable to monitor a signal associated with the transponder;

wherein the adjuster is further operable to, based on the monitored signal, determine a second best configuration of the reader antenna assembly; and

wherein the controller is further operable to, based on the second best configuration, adjust the one or more registers to change the at least one parameter associated with operation of the reader antenna assembly.

13. The receiver of claim 12, wherein the reader antenna assembly is further operable to read a credential provided by the transponder.

14. The receiver of claim 13, wherein the adjuster is further operable to store the settings of the one or more registers;

wherein the initial information includes one of an identifier for the transponder or an indication of a type of transponder;

wherein, based on one of the identifier for the transponder or the indication of the type of transponder, the adjuster operable to;

retrieve stored settings determined during a previous connection with the transponder; and

provide the stored settings as the best configuration.

15. The receiver of claim 13, wherein the adjuster is further operable to store the settings of the one or more registers;

wherein the initial information includes one or more environmental conditions encountered when detecting the transponder;

wherein, based on one or more environmental conditions, the adjuster operable to;

retrieve stored settings determined during a second previous connection with a second transponder, wherein the second previous connection had one or more similar environmental conditions as the one or more environmental conditions; and

provide the stored settings as the best configuration.

16. A non-transitory computer readable medium including instructions stored in a memory and read by a processor of a reader, wherein the instructions cause the reader to execute a method comprising:

receiving an initial detection of a transponder;

receiving initial information about the transponder;

based on the initial information, determining a best configuration for a reader antenna assembly while the transponder is at least a first distance away from the reader;

based on the best configuration and while the transponder is at least the first distance away from the reader, setting one or more registers that change at least one parameter associated with operation of the reader antenna assembly, wherein the one or more registers are included in a tuning circuit of the reader;

monitoring a signal associated with the transponder and determining that the transponder is less than the first distance away from the reader;

based on the monitored signal, determining a second best configuration of the reader antenna assembly;

based on the second best configuration, adjusting the one or more registers of the tuning circuit to change the at least one parameter associated with operation of the reader antenna assembly; and

reading a credential provided by the transponder.

17. The computer readable medium of claim 16, further comprising storing the settings of the one or more registers.

18. The computer readable medium of claim 17, wherein the initial information includes one of an identifier for the transponder or an indication of a type of transponder;

wherein the method further comprises;

based on one of the identifier for the transponder or the indication of the type of transponder, retrieving stored settings determined during a previous connection with the transponder; and

providing the stored settings as the best configuration.

19. The computer readable medium of claim 18, wherein the initial information includes one or more environmental conditions encountered when detecting the transponder;

wherein the method further comprises;

based on the one or more environmental conditions, retrieving second stored settings determined during a second previous connection with a second transponder, wherein the second previous connection had one or more similar environmental conditions as the one or more environmental conditions; and

providing the second stored settings as the best configuration.

20. The computer readable medium of claim 19, wherein the at least one parameter is associated with one of a gain, a filter level, a threshold level, capacitance, or an impedance.