Method of transmitting data with optimized transmission rate using packet header that defines data encoding parameters

• US 20030133435A1
• Filed: 01/28/2003
• Published: 07/17/2003
• Est. Priority Date: 08/03/2001
• Status: Active Grant

• Current Assignee: Atmel Corporation (Microchip Technology Incorporated)
• Original Assignee: Atmel Germany GmbH (Microchip Technology Incorporated)
• Inventors: Friedrich, Ulrich
• Granted Patent: US 7,385,950 B2
• Time in Patent Office: Days
• US Class Current: 370/349
• 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 7/10297 arrangements for handling protocols designed for non-contact record carriers such as RFIDs NFCs, e.g. ISO/IEC 14443 and 18092 cryptographic protocols H04L9/00; network security protocols H04L63/00; real-time communication protocols in data switching networks H04L65/00; network protocols for data switching network services H04L67/00
• CPC Class Codes: H04L 1/0014 by adapting the source coding

Abstract

For transmitting data between a base station and a transponder, information packets modulated onto an electromagnetic carrier wave each include a header section, a middle section, and an end section. The data are encoded in the middle section using information symbols, e.g. representing digital “1s” and “0s”. The header section of at least the first packet defines the number and unique identifications of all of the symbols that will be used for encoding the data in the middle section of this and/or subsequent packets. This transmission protocol defined in the header section can be varied in subsequent packets to adaptively adjust the transmission rate depending on the existing communication conditions and requirements such as high frequency regulations prescribed by national law. The transmission rate can be considerably increased, in comparison to a transmission rate that would otherwise be necessary for achieving a reliable transmission even under unfavorable conditions.

Claims

1. A method of transmitting data between a base station and a transponder, one of which may operate as a transmitter and another of which may operate as a receiver, comprising the following steps:

transmitting an electromagnetic carrier wave from said transmitter to said receiver;

in said transmitter, modulating a succession of information packets onto said electromagnetic carrier wave, wherein each one of said information packets comprises a header section, a middle section, and an end section, wherein said header section of at least a selected beginning one of said information packets includes a respective identification defining each information symbol of a set of information symbols, wherein said respective identification of at least one of said information symbols is a variable identification, and wherein said middle section of said selected beginning information packet or of one or more subsequent information packets after said selected beginning information packet includes said data that is encoded by said information symbols including said at least one information symbol defined by said variable identification and that is modulated onto said carrier wave;

in said receiver, receiving said electromagnetic carrier wave with said information packets modulated thereon;

evaluating said header section of said selected beginning information packet in said receiver to determine said respective identification of each said information symbol of said set of information symbols; and

decoding said data in said receiver based on said identifications of said information symbols.

2. The method according to claim 1, wherein said header section of said selected beginning information packet further indicates the number of said information symbols included in said set.

3. The method according to claim 1, wherein said respective identification respectively defining each said information symbol comprises a time duration of a modulation condition used for said modulating, onto said carrier wave, of said data encoded by said information symbols, and wherein said method further comprises changing said time duration of said modulation condition of said variable identification to a changed time duration.

4. The method according to claim 1, wherein said information symbols include a first symbol representing a binary one value and a second symbol representing a binary zero value.

5. The method according to claim 4, wherein said first symbol comprises a first signal pulse modulated onto said electromagnetic carrier wave, said second symbol comprises a second signal pulse modulated onto said electromagnetic carrier wave, said respective identification of said first symbol comprises a first parameter that characteristically defines said first signal pulse, and said respective identification of said second symbol comprises a second parameter that characteristically defines said second signal pulse.

6. The method according to claim 5, wherein said modulating is carried out as a pulse width modulation, said first parameter is a first pulse duration of said first signal pulse, and said second parameter is a second pulse duration of said second signal pulse.

7. The method according to claim 6, wherein said first and second pulse durations included in said header section are respective nominal values of a pulse duration of said first signal pulse representing said binary one value and of said second signal pulse representing said binary zero value, respectively.

8. The method according to claim 6, wherein said first and second pulse durations included in said header section are respective maximum or minimum limit values of a pulse duration of said first signal pulse representing said binary one value and of said second signal pulse representing said binary zero value, respectively.

9. The method according to claim 1 wherein each said respective identification of any given one of said information symbols in said header section comprises a minimum limit value or a maximum limit value of a duration of a modulation internal of said modulating that is characteristic of said given one of said information symbols.

10. The method according to claim 9, wherein said data are encoded with said information symbols in said middle section by modulating said electromagnetic carrier wave with respective modulation intervals having respective nominal durations greater than said minimum limit value and less than said maximum limit value that are characteristic for each given one of said information symbols respectively.

11. The method according to claim 1, wherein a first value is allocated to said identification of at least a given one of said information symbols in said header section, and a second value different from said first value is allocated to said given information symbol used for encoding said data with said given information symbol in said middle section.

12. The method according to claim 1, wherein said transmitter specifies and fixes a transmission protocol to be used in said transmitting of said data at a beginning of said transmitting by specifying said identifications of said information symbols in said header section, which define said transmission protocol.

13. The method according to claim 12, wherein said transmission protocol remains in effect, and said information symbols of said header section of said selected beginning information packet are used for encoding said data in said middle section of said selected beginning information packet and in said middle sections of said subsequent ones of said information packets.

14. The method according to claim 13, wherein said header sections of said subsequent ones of said information packets do not include an identification of said information symbols.

15. The method according to claim 13, wherein said header section of a further successive one of said information packets following after said subsequent information packets includes only an identification of only any one or more of said information symbols that has changed or differs from said information symbols of said set of information symbols of which said identifications were included in said header section of said selected beginning information packet.

16. The method according to claim 1, wherein said header sections of said subsequent information packets respectively include only an identification of only any one or more of said information symbols that has changed or differs from said information symbols of said set of information symbols of which said identifications were included in said header section of said selected beginning information packet.

17. The method according to claim 1, wherein said header section of each given one of said information packets includes a respective identification of each information symbol that is to be used for encoding said data in said middle section of that said given one of said information packets, and wherein said middle section of that said given one of said information packets includes said data encoded by said information symbols of which said respective identification is included in said header section of that said given one of said information packets.

18. The method according to claim 1, wherein said identifications of said information symbols in said header section determine a data transmission rate of said transmitting of said data, and further comprising changing said data transmission rate by changing said identifications of said information symbols in said header section of at least one of said subsequent information packets relative to said selected beginning information packet without carrying out any hardware modifications in said base station or said transponder.

19. The method according to claim 18, further comprising carrying out said changing of said data transmission rate responsive to transmission conditions so as to achieve a fastest value of said data transmission rate while still reliably performing said receiving, evaluating and decoding steps.

20. The method according to claim 1, further comprising, after said step of receiving said electromagnetic carrier wave, a step of transmitting a response signal from said receiver back to said transmitter.

21. The method according to claim 20, wherein said response signal includes a field strength information that is indicative of a field strength of said electromagnetic carrier wave being received by said receiver.

22. The method according to claim 21, wherein said receiver is said transponder, which is a passive transponder, and wherein said field strength information is derived from a present value of a supply voltage of said passive transponder.

23. The method according to claim 20, wherein said receiver is said transponder, which is a passive transponder, and wherein said response signal includes a supply voltage that is indicative of a present value of a supply voltage of said passive transponder.

24. The method according to claim 23, wherein said transmitter is said base station, and further comprising, in said base station,

evaluating said supply voltage information so as to compare said present value of said supply voltage of said passive transponder to a prescribed maximum threshold value or a prescribed minimum threshold value, and

if said present value of said supply voltage falls above said maximum threshold value or below said minimum threshold value, then changing at least one of said identifications so that a header section of a following one of said information packets includes a different identification of at least one information symbol that is different in comparison to said header section of said selected beginning information packet.

25. The method according to claim 23, wherein said identifications of said information symbols in said header section determine a data transmission rate of said transmitting of said data, and further comprising changing said data transmission rate by changing said identifications of said information symbols in said header section of at least one of said subsequent information packets relative to said selected beginning information in response to and dependent on said supply voltage information included in said response signal.

26. The method according to claim 20, wherein said response signal includes receiver information indicative of at least one of an optimum transmission protocol of said receiver and a reception characteristic of said receiving of said electromagnetic carrier wave by said receiver, and further comprising, in said transmitter, successively changing at least one of a number of said information symbols and said identifications of said information symbols in said header sections of successive ones of said information packets responsive to and dependent on said receiver information in said response signal until said receiver information corresponds to a prescribed encoding.

27. The method according to claim 26, wherein said step of successively changing comprises successively increasing or decreasing said number of said information symbols in said header sections of said successive ones of said information packets beginning from a prescribed starting value of said number of said information symbols.

28. The method according to claim 26, wherein said identifications comprise respective unique durations of respective modulation intervals characterizing said information symbols, and said step of successively changing comprises successively increasing or decreasing said of said modulation intervals in said header sections of said successive ones of said information packets beginning from respective prescribed starting values of said durations of said information symbols.

29. The method according to claim 26, wherein said step of successively changing is re-initiated and carried out repeatedly.

30. The method according to claim 1, wherein said transmitter is said base station, said receiver is said transponder which is a passive transponder, said identifications of said information symbols define a transmission protocol, and said transmission protocol is specified by said base station and is adopted and followed by said passive transponder.

31. A method of transmitting data between a base station and a transponder by means of an electromagnetic wave, with information packets including various symbols modulated onto the electromagnetic wave, wherein the information packets respectively comprise a header section, a middle section with a data section, and an end section, characterized in that

the number and the identification of the symbols is given in the header section of at least one of the information packets, and at least one of the symbols is defined by a variable identification;

and

the data are encoded by means of the variable identification and are transmitted in the middle section of the at least one information packet, or a subsequent information packet following the at least one information packet.

32. A method according to claim 31, characterized in that the variable identification comprises a variable time duration of an existing modulation condition, which is changed to a changed time duration to provide the next modulation condition.