Method for data transmission in RFID or remote sensor systems
A method and apparatus for transmitting data in a radio frequency identification system, which includes a reader and at least one transponder, is provided. The reader transmits data sequences to the transponder including at least command data, associated check data, and a subsequent return link header data. Upon receiving unrecognized command data and/or unsupported parameter and address data the transponder notifies the reader of this condition. The notification takes place at times when the reader transmits end signals indicating an end of a data sequence, transmits an optional parameter and address data, or transmits the return link header data. Thus, communication between the reader and other transponders is not disrupted when a transponder cannot execute a command.
1. A method for transmitting data in a radio frequency identification system having a reader and at least one transponder, or for transmitting data between a reader and a remote sensor, the method comprising:
transmitting a data sequence from the reader to the transponder or the remote sensor, the data sequence including command data accompanied by associated check data and/or parameter and address data accompanied by correct check data, and return link header data for providing a return link from the transponder or the remote sensor to the reader;
determining by the transponder or the remote sensor of an unrecognized command data and/or unsupported parameter and address data accompanied in each case by correct check data; and
notifying the reader of the unrecognized command data and/or unsupported parameter and address data while the reader transmits end signals indicating an end of the data sequence or an end of the parameter and address data, or while the return link header data is transmitted.
2. The method according to claim 1 , wherein the reader is notified of the unrecognized command data and/or the unsupported parameter and address data at different respective times within the data sequence.
3. The method according to claim 1 , wherein a transmission from the reader is modulated in order to notify the reader.
4. The method according to claim 1 , wherein a transmission from the transponder or sensor to the reader is terminated in order to notify the reader.
5. The method according to claim 4 , wherein, after the termination of the transmission from the transponder or sensor, the reader terminates a transmission in progress and transmits a new data sequence.
6. The method according to claim 5 , wherein the new data sequence contains command data recognized by all transponders or sensors that are associated with the system and/or parameter and address data supported by all the transponders or sensors.
7. The method according to claim 1 , wherein, after notifying the reader, the transponder or sensor withdraws from communication with the reader until new recognized command data is received.
8. The method according to claim 1 , wherein the data sequence further includes optional parameter and address data.
9. The method according to claim 1 , wherein the reader is notified of the unrecognized command data and/or the unsupported parameter and address data upon transmission of the end signals or the transmission of the return link header data as header data.
10. A transponder comprising:
an antenna; and
an integrated circuit being electrically connected to the antenna,
wherein the transponder receives by the antenna at least a transmitted data sequence, the transmitted data sequence including an end of data portion and a return link header portion,
wherein, upon detection of an unrecognized command data and/or unsupported parameter and address data accompanied in each case by correct check data, an unrecognized command code is transmitted during receipt of the end of data portion or the return link header portion, and
wherein when no unrecognized command data and/or unsupported parameter and address data is detected, the transponder transmits data after receipt of the return link header portion.
11. The transponder according to claim 10 , wherein the transmitted data sequence further includes a command data portion, a check data portion, an additional parameter and address data portion, and an additional check data portion.
12. The transponder according to claim 11 , wherein the command data portion, the check data portion, the additional parameter and address data portion, and the additional check data portion precede the end of data portion and the return link header portion in the data sequence.
13. The transponder according to claim 10 , wherein the unrecognized command code is transmitted to a reader.
14. The transponder according to claim 13 , wherein the reader transmits the data sequence to the transponder.
15. The transponder according to claim 10 , wherein, upon detection of the unrecognized command data and/or unsupported parameter and address data, the unrecognized command code is transmitted only during receipt of the end of data portion or the return link header portion.
16. The transponder according to claim 10 , wherein the unrecognized command code is selectively transmitted during the receipt of the end of data portion or the return link header portion based on a cause of the unrecognized command data and/or unsupported parameter and address data.
17. The method according to claim 1 , wherein a time when the reader is notified of the unrecognized command data and/or unsupported parameter and address data is based on a cause of the unrecognized command data and/or unsupported parameter and address data.
18. The method according to claim 1 , wherein, if the received data sequence includes the unrecognized command data, the reader is notified of the error at a first time within the data sequence, and
wherein, if the received data sequence includes the unsupported parameter and address data, the reader is notified of the unrecognized command data and/or unsupported parameter and address data at a second time within the data sequence.
19. The method according to claim 1 , wherein, if the received data sequence includes the unrecognized command data, the reader is notified of the error only when the reader is transmitting the end signals, and
wherein, if the received data sequence includes the unsupported parameter and address data, the reader is notified of the unrecognized command data and/or unsupported parameter and address data only when the reader is transmitting the return link header data.
20. The method according to claim 1 , further comprising:
determining a cause of the unrecognized command data and/or unsupported parameter and address data based on whether the reader is notified of the unrecognized command data and/or unsupported parameter and address data when the reader transmits the end signals indicating the end of the data sequence or the end of the parameter and address data, or when the return link header data is transmitted.
21. The method according to claim 1 , wherein the data sequence further includes header data, and
wherein the header data, the command data, the associated check data, the parameter and address data, and the correct check data each precede the end signals and the return link header data in the data sequence.
22. The method according to claim 1 , wherein the reader is a multi-protocol reader.
23. the method according to claim 1 wherein said at least one transponder comprises at least two transponders.