Wireless activation system, method and device

• US 20060164207A1
• Filed: 11/19/2003
• Published: 07/27/2006
• Est. Priority Date: 11/30/2002
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Wilcox, Martin S.
• Granted Patent: US 7,646,283 B2
• Time in Patent Office: Days
• US Class Current: 340/5.610
• CPC Class Codes: B60R 25/24 using electronic identifiers containing a code not memorised by the user
• CPC Class Codes: G07C 2009/00555 comprising means to detect or avoid relay attacks
• CPC Class Codes: G07C 2009/00793 by Hertzian waves
• CPC Class Codes: G07C 2209/06 Involving synchronization or resynchronization between transmitter and receiver; reordering of codes
• CPC Class Codes: G07C 9/00182 operated with unidirectional data transmission between data carrier and locks
• CPC Class Codes: G07C 9/00309 operated with bidirectional data transmission between data carrier and locks

Abstract

A wireless activation system, such as a keyless car entry system, uses repeated code sequences (mk) for communication between a transmitter device (400) and a receiver device (200). By varying the sequence duration in a synchronism at the transmitter device and receiver device, either by varying the number of symbols or chips in the sequence, or by varying the symbol or chip rate, it is made more difficult for an unauthorised party to detect the code sequences and relay the code sequences to achieve unauthorised activation at the receive device (200).

Claims

1. A wireless activation system comprising a first device (400) having means (460,420) for generating and transmitting a code signal, wherein each successive transmission of the code signal comprises a successive code sequence from a succession of code sequences, and a second device (200) having means (210,240,250,260) for generating the succession of code sequences in synchronism with the first device, means (110) for receiving the code signal, means (160) for detecting the successive code sequence transmitted by the first device, means (210) for generating an indication of the time of flight of the code signal, and means (210) for generating an activation signal in response to the combination of the detected successive code sequence corresponding to the successive code sequence generated most recently by the second device and the indication of the time of flight being within a predetermined range of values, wherein the succession of code sequences comprises code sequences of different time durations.

2. A wireless activation system as claimed in claim 1, wherein the code sequences of different time durations comprise code sequences of different symbol or chip durations.

3. A wireless activation system as claimed in claim 1, wherein the code sequences of different time durations comprise code sequences of different numbers of symbols or chips.

4. A wireless activation system as claimed in claim 1, 2 or 3, wherein the means (460,420) for generating and transmitting the code signal comprises means (440) for changing the time duration of the transmitted successive code sequence in response to the elapse of a predetermined time period.

5. A wireless activation system as claimed in claim 1, 2 or 3, wherein the means for generating and transmitting the code signal comprises means (410) for changing the time duration of the transmitted successive code sequence in response to the transmission of a predetermined number of the code signals.

6. A wireless activation system as claimed in any one of claims 1 to 5, wherein the means (210) for generating the activation signal is responsive to the indication of the time of flight being below a predetermined limit.

7. A wireless activation system as claimed in claim 6, and wherein the second device (200) further comprises means (300) responsive to the activation signal for activating or deactivating a locking means.

8. A wireless activation system as claimed in claim 7, wherein the second device (200) further comprises the locking means (300).

9. A wireless activation system as claimed in claim 7, wherein the wireless activation system is a vehicle security system.

10. A wireless activation system as claimed in any one of claims 1 to 5, wherein the means (210) for generating the activation signal is responsive to the indication of the time of flight being above a predetermined limit.

11. A wireless activation system as claimed in claim 10, wherein the second device (200) further comprises means (300) responsive to the activation signal for generating an alert.

12. A wireless activation system as claimed in claim 11, wherein the wireless activation system is a system for tagging a person, animal or object.

13. A wireless activation system as claimed in any one of claims 1 to 12, wherein each code sequence comprises a spread spectrum sequence.

14. A wireless activation system as claimed in claim 13, wherein the spread spectrum sequence is a frequency hopping sequence.

15. A method of wireless activation comprising at a first device (400) generating and transmitting a code signal, wherein each successive transmission of the code signal comprises a successive code sequence from a succession of codes, and at a second device (200) generating the succession of code sequences in synchronism with the first device, receiving the code signal, detecting the successive code sequence transmitted by the first device (400), generating an indication of the time of flight of the code signal, and generating an activation signal in response to the combination of the detected successive code sequence corresponding to the successive code sequence generated most recently by the second device (200) and the indication of the time of flight being within a predetermined range of values, wherein the succession of code sequences comprises code sequences of different time durations.

16. A method of wireless activation as claimed in claim 15, wherein the code sequences of different time durations comprise code sequences of different symbol or chip durations.

17. A method of wireless activation as claimed in claim 15, wherein the code sequences of different time durations comprise code sequences of different numbers of symbols or chips.

18. A method of wireless activation as claimed in claim 15, 16 or 17, wherein the time duration of the transmitted code sequence is changed in response to the elapse of a predetermined time period.

19. A method of wireless activation as claimed in claim 15, 16 or 17, wherein the time duration of the transmitted code sequence is changed in response to the transmission of a predetermined number of the code signals.

20. A transmitter device (400) for use in wireless activation system, comprising means (460,420) for generating and transmitting a code signal wherein each successive transmission of the code signal comprises a successive code sequence from a succession of code sequences and wherein the succession of code sequences comprises code sequences of different time durations.

21. A transmitter device (400) as claimed in claim 20, wherein the code sequences having different time durations comprise code sequences having different symbol or chip durations.

22. A transmitter device (400) as claimed in claim 20, wherein the code sequences having different time durations comprise code sequences having different numbers of symbols or chips.

23. A receiver device (200) for use in a wireless activation system, comprising means (210,240,250,260) for generating a succession of code sequences, means (110) for receiving a code signal, means (160) for detecting a code sequence conveyed by the code signal, means (210) for generating an indication of the time of flight of the code signal, and means (210) for generating an activation signal in response to the combination of the detected code sequence corresponding to the code sequence generated most recently and the indication of the time of flight being within a predetermined range of values, wherein the succession of code sequences comprises code sequences having different time durations.

24. A receiver device (200) as claimed in claim 23, wherein the code sequences having different time durations comprise code sequences having different symbol or chip durations.

25. A receiver device (200) as claimed in claim 23, wherein the code sequences having different time durations comprise code sequences having different numbers of symbols or chips.

26. A receiver device (200) as claimed in claim 23, 24, or 25, further comprising means (240) to change the time duration of the generated code sequences in response to the elapse of a predetermined time period.

27. A receiver device (200) as claimed in claim 23, 24, or 25, further comprising means (210) to change the time duration of the generated code sequences in response to the generation of a predetermined number of the successive code sequences.

28. A receiver device (200) as claimed in any one of claims 23 to 27, wherein the means (210) for generating the activation signal is responsive to the indication of the time of flight being below a predetermined limit.

29. A receiver device (200) as claimed in any one of claims 23 to 27, wherein the means (210) for generating the activation signal is responsive to the indication of the time of flight being above a predetermined limit.