Wireless activation system, method and device

• US 7,646,283 B2
• Filed: 11/19/2003
• Issued: 01/12/2010
• 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.
• Primary Examiner(s): Brown; Vernal U
• Application Number:
  US10/536,246
• Publication Number:
  US 20060164207A1
• Time in Patent Office: 2,246 Days
• Field of Search: 340/5.61, 340/5.64, 340/10.1, 340/5.6, 340/825.22, 340/5.1, 340/5.2, 340/5.21, 340/5.8, 341/67, 341/51, 341/114
• US Class Current: 340/5.61
• 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 for communication between a transmitter device and a receiver device. 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.

Claims

1. A wireless activation system comprising:

a first device that is configured to generate and transmit a code signal, wherein each successive transmission of the code signal includes a successive code sequence from a succession of code sequences, and

a second device that is configured to;

generate the succession of code sequences in synchronism with the first device,

receive the code signal,

detect the successive code sequence transmitted by the first device,

generate an indication of a time of flight of the code signal, and

generate 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 includes code sequences of different time durations, and wherein the successive code sequence includes a concatenation of the code sequence with itself a plurality of times.

2. The wireless activation system of claim 1, wherein the code sequences of different time durations include code sequences of different symbol or chip durations.

3. The wireless activation system of claim 1, wherein the code sequences of different time durations include code sequences of different numbers of symbols or chips.

4. The wireless activation system of claim 1, wherein the first device is configured to change the time duration of the transmitted successive code sequence in response to the elapse of a predetermined time period.

5. The wireless activation system of claim 1, wherein the first device is configured to change the time duration of the transmitted successive code sequence in response to the transmission of a predetermined number of the code signals.

6. The wireless activation system of claim 1, wherein the second device is configured to generate the activation signal in response to the indication of the time of flight being below a predetermined limit.

7. The wireless activation system of claim 6, wherein the second device is configured to activate or deactivate a lock in response to the activation signal.

8. The wireless activation system of claim 7, wherein the second device includes the lock.

9. The wireless activation system of claim 7, wherein the wireless activation system is a vehicle security system.

10. The wireless activation system of claim 1, wherein the second device is configured to generate the activation signal in response to the indication of the time of flight being above a predetermined limit.

11. The wireless activation system of claim 10, wherein the second device is configured to generate an alert in response to the activation signal.

12. The wireless activation system of claim 11, wherein the wireless activation system is a system for tagging a person, animal or object.

13. The wireless activation system of claim 1, wherein each code sequence includes a spread spectrum sequence.

14. The wireless activation system of claim 13, wherein the spread spectrum sequence is a frequency hopping sequence.

15. A method of wireless activation comprising:

at a first device, generating and transmitting a code signal, wherein each successive transmission of the code signal includes a successive code sequence from a succession of codes, and

at a second device;

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,

generating an indication of a 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 and the indication of the time of flight being within a predetermined range of values,

wherein the succession of code sequences includes code sequences of different time durations, and wherein the successive code sequence includes a concatenation of the code sequence with itself a plurality of times.

16. The method of wireless activation of claim 15, wherein the code sequences of different time durations include code sequences of different symbol or chip durations.

17. The method of wireless activation of claim 15, wherein the code sequences of different time durations include code sequences of different numbers of symbols or chips.

18. The method of wireless activation of claim 15 wherein the time duration of the transmitted code sequence is changed in response to the elapse of a predetermined time period.

19. The method of wireless activation of claim 15 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 for use in a wireless activation system, comprising:

a code generator that is configured to generate a code signal,

a transmitter that is configured to transmit the code signal,

wherein each successive transmission of the code signal includes a successive code sequence from a succession of code sequences and wherein the succession of code sequences includes code sequences of different time durations, and wherein the successive code sequence includes a concatenation of the code sequence with itself a plurality of times.

21. The transmitter device of claim 20, wherein the code sequences having different time durations include code sequences having different symbol or chip durations.

22. The transmitter device of claim 20, wherein the code sequences having different time durations include code sequences having different numbers of symbols or chips.

23. A receiver device for use in a wireless activation system, comprising:

a generator that is configured to generate a succession of code sequences,

a receiver that is configured to receive a code signal,

a detector that is configured to detect a code sequence conveyed by the code signal,

an other generator that is configured to generate an indication of a time of flight of the code signal, and

a further generator that is configured to generate 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 includes code sequences having different time durations, and wherein the successive code sequence includes a concatenation of the code sequence with itself a plurality of times.

24. The receiver device of claim 23, wherein the code sequences having different time durations include code sequences having different symbol or chip durations.

25. The receiver device of claim 23, wherein the code sequences having different time durations include code sequences having different numbers of symbols or chips.

26. The receiver device of claim 23, including means to change the time duration of the generated code sequences in response to the elapse of a predetermined time period.

27. The receiver device of claim 23, including means 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. The receiver device of claim 23, wherein the further generator generates the activation signal in response to the indication of the time of flight being below a predetermined limit.

29. The receiver device of claim 23, wherein the further generator generates the activation signal in response to the indication of the time of flight being above a predetermined limit.