Electronic identification system with forward error correction system

• US 6,686,829 B1
• Filed: 01/19/1999
• Issued: 02/03/2004
• Est. Priority Date: 01/19/1998
• Status: Expired due to Term

• Current Assignee: Zebra Technologies Corporation
• Original Assignee: ZIH Corp. (Zebra Technologies Corporation)
• Inventors: Hohberger, Clive Paul, Turner, Christopher Gordon Gervase
• Primary Examiner(s): Horabik; Michael
• Assistant Examiner(s): BROWN, VERNAL U
• Application Number:
  US09/234,149
• Time in Patent Office: 1,841 Days
• Field of Search: 340/10.1,10.3,10.4,10.41,10.51,3.43,3.44 724/750,754,776,726,755,7.44,751,752,786,807,756,758,792
• US Class Current: 340/10.1
• 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 first radio frequency (RF) interrogation signal;

a plurality of radio frequency transponders;

each transponder being operative in response to the interrogation signal to respond with a forward error correctable data message including;

base data in the form of identification code data unique to the transponder encoded as a first set of symbol characters in accordance with a first forward error correcting code, a first set of check characters on the identification code data as defined in the first forward error correcting code, other base data encoded as a second set of symbol characters in accordance with a second forward error correcting code and a second set of check characters on the other base data as defined in the second forward error correcting code, for facilitating reconstruction of the identification code data and other 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 messages; and

data processor means programmed to utilize data relating to the first forward error correcting code, the first set of symbol characters and the first set of check characters in the received forward error correctable data message; and

further programmed to utilize data relating to the second forward error correcting code, the second set of symbol characters and the second set of check characters in the received forward error correctable data message, to reconstruct the identity code data and the other base data respectively, 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 first forward error correcting code and the second forward error correcting code are of different types.

3. A system as claimed in claim 1 wherein the interrogator is controllable to transmit the first and a second interrogation signal;

wherein each transponder is operative in response to the first interrogation signal to respond with a first forward error correctable data message including the first set of symbol characters and the first set of check characters;

wherein each transponder is further responsive in response to the second interrogation signal to respond with a second error correctable data message including the second set of symbol characters and the second set of check characters; and

wherein the data processor means is programmed to utilize the data relating to the first error correcting code, the first set of symbol characters and the first set of check characters in the received first forward error correctable data message to reconstruct the identification code data in the event of corruption of the received first forward error correctable data message; and

wherein the data processor means is further programmed to utilize the data relating to the second error correcting code, the second set of symbol characters and the second set of check characters in the received second forward error correctable data message, to reconstruct the other base data in the event of corruption of the received second forward error correctable data message.

4. 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 a first interrogation signal to be transmitted by the interrogator; and

causing the transponder to respond to the interrogation signal with a forward error correctable data message including;

base data in the form of identification code data unique to the transponder encoded as a first set of symbol characters in accordance with a first forward error correcting code, a first set of check characters on the identification code data as defined in the first forward error correcting code, other base data encoded as a second set of symbol characters in accordance with a second forward error correcting code and a second set of check characters on the other base data as defined in the second forward error correcting code;

receiving the forward error correctable data message; and

causing an error correction means to utilize data relating to the first forward error correcting code, the first set of symbol characters and the first set of check characters in the received forward error correctable data message; and

further to utilize data relating to the second forward error correcting code, the second set of symbol characters and the second set of check characters in the received forward error correctable data message, in order to reconstruct the identity code data and the other base data respectively, in the event of corruption of the received forward error correctable data message.

5. A method as claimed in claim 4 wherein the first forward error correcting code and the second forward error correcting code are of different types.

6. A method as claimed in claim 5, including the steps of:

causing a selected one of the first and a second interrogation signal to be transmitted;

causing each transponder in response to the first interrogation signal to respond with a first forward error correctable data message including the first set of symbol characters and the first set of check characters;

causing each transponder in response to the second interrogation signal to respond with a second error correctable data message including the second set of symbol characters and the second set of check characters;

causing the first and second error correctable data messages to be received;

causing the error correction means to utilize data relating to the first error correcting code, the first set of symbol characters and the first set of check characters in the received first forward error correctable data message to reconstruct the identification code data in the event of corruption of the received first forward error correctable data message; and

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