Electronic identification system with forward error correction system

• US 20050237155A1
• Filed: 06/24/2005
• Published: 10/27/2005
• Est. Priority Date: 01/19/1998
• Status: Active Grant

• Current Assignee: Zebra Technologies Corporation
• Original Assignee: ZIH Corp. (Zebra Technologies Corporation)
• Inventors: Turner, Christopher Gordon Gervase, Hohberger, Clive Paul
• Granted Patent: US 7,327,218 B2
• Time in Patent Office: Days
• US Class Current: 340/10.100
• 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 7/10039 interrogator driven, i.e. synchronous

Abstract

An electronic radio frequency (RF) identification system 10 is disclosed and claimed. The system includes an interrogator 11 and a plurality of RF transponders 12.1 to 12.n. In use, each transponder is operative in response to an interrogation signal 14 to respond with a forward error correctable data message 16.1 including base data encoded as symbol characters in accordance with a forward error correcting code, such as a Reed Solomon Code, and check characters on the base data as defined in the forward error correcting code. The interrogator 11 utilizes data relating to the forward error correcting code, the symbol characters and check characters in the received forward error correctable data message, to reconstruct the base data in the event of corruption of the forward error correctable data message during transmission.

Claims

1. An electronic identification system including:

an interrogator for transmitting a radio frequency interrogation signal;

a plurality of radio frequency transponders;

each transponder being operative in response to the interrogation signal to respond by backscatter modulation of the interrogation signal with a forward error correctable data message, the message including base data encoded as a set of symbol characters in accordance with a forward error correcting code and a set of check characters based on the base data as defined in the forward error correcting code, for facilitating reconstruction of the base data in the event of corruption of the forward error correctable data message during transmission; and

the interrogator including

receiver means for receiving the forward error correctable data message; and

data processor means programmed to utilize data relating to the forward error correcting code, the symbol characters and the check characters in the received forward error correctable data message, to reconstruct the transponder identifying base data in the event of corruption of the received forward error correctable data message.

2. An electronic identification system as claimed in claim 1 wherein the forward error correcting code is a member of the class of trellis codes.

3. An electronic identification system as claimed in claim 2 wherein the forward error correcting code is a member of the class of convolutional codes.

4. An electronic identification system as claimed in claim 1 wherein the forward error correcting code is a member of the class of linear block codes.

5. An electronic identification system as claimed in claim 4 wherein the forward error correcting code is a Hamming Code.

6. An electronic identification system as claimed in claim 4 wherein the forward error correcting code is a Binary Golay Code.

7. An electronic identification system as claimed in claim 4 wherein the forward error correcting code is a Reed-Muller Code.

8. An electronic identification system as claimed in claim 1 wherein the forward error correcting code is a member of the class of cyclic block codes.

9. An electronic identification system as claimed in claim 8 wherein the forward error correcting code is a Fire Code.

10. An electronic identification system as claimed in claim 8 wherein the forward error correcting code is a Bose-Chaudauri-Hocquenghem Code.

11. An electronic identification system as claimed in claim 8 wherein the forward error correcting code is a Reed-Solomon Code.

12. An electronic identification system as claimed in claim 1 including a code generator means for generating the forward error correctable data message by encoding the base data as the set of symbol characters in accordance with the forward error correcting code and for generating the check characters on the based on the base data as defined in the forward error correcting code, the code generator means being separate from the transponders;

and wherein each transponder includes;

a data memory arrangement into which the forward error correctable data message generated by the code generator means is stored; and

control circuitry for causing the transponder to respond with the stored forward error correctable data message in response to the interrogation signal.

13. An electronic identification system as claimed in claim 12 wherein the code generator means forms part of the interrogator.

14. An electronic identification system as claimed in claim 1 wherein each transponder includes:

a data memory arrangement configured to be programmed with the transponder identifying base data and other base data for storage therein; and

local code generator means forming part of the transponder for locally generating the forward error correctable data message by encoding the base data the set of symbol characters in accordance with the error correcting code and for generating the check characters as defined in the forward error correcting code.

15. A transponder for use with an electronic identification system including an interrogator for transmitting a radio frequency interrogation signal and for receiving a response signal from the transponder, the transponder including

control means;

and

a data memory arrangement into which is programmable data associated with the transponder;

the control means being operative in response to an interrogation signal to utilize the data associated with the transponder to cause the transponder to respond by backscatter modulation of the interrogation signal with a forward error correctable data message, the message including;

i) base data relating to the transponder, the base data encoded as symbol characters in accordance with a forward error correcting code; and

check characters on the base data as defined in the forward error correcting code, for facilitating reconstruction of the base data in the event of corruption of the forward error correctable data message during transmission.

16. A transponder as claimed in claim 15 wherein the data memory arrangement is configured to be programmed with the forward error correctable data message as pre-generated by an external code generation means for storage therein;

and wherein the control means, in use, utilizes the stored forward error correctable data message to respond to the interrogation signal.

17. A transponder as claimed in claim 15 wherein the data memory arrangement is configured to be programmed with the base data;

wherein the transponder includes local code generator means for locally generating the forward error correctable data message by encoding the base data as symbol characters in accordance with the error correcting code and for generating the check characters based on the base data as defined in the forward error correcting code; and

wherein the control means, in use, utilizes the locally generated forward error correctable data message to respond to the interrogation signal.

18. A method of operating an electronic radio frequency identification system including an interrogator and at least one transponder;

the method including the steps of;

causing an interrogation signal to be transmitted by the interrogator;

causing the transponder to respond by backscatter modulation of the interrogation signal with a forward error correctable data message, the message including base data encoded as a set of symbol characters in accordance with the forward error correcting code and a set of check characters based on the base data in accordance with the forward error correcting code, for facilitating reconstruction of the base data in the event of corruption of the forward error correctable data message during transmission;

receiving the forward error correctable data message; and

causing an error correction means to utilize data relating to the forward error correcting code, the set of symbol characters and the set of check characters in the received forward error correctable data message, in order to reconstruct the base data in the event of corruption of the received forward error correctable data message.