Frequency hopping for passive start and entry systems

• US 20060202798A1
• Filed: 02/02/2006
• Published: 09/14/2006
• Est. Priority Date: 03/08/2005
• Status: Abandoned Application

• Current Assignee: Siemens VDO Automotive Corporation (Siemens AG)
• Original Assignee: Siemens VDO Automotive Corporation (Siemens AG)
• Inventors: Baumgartner, Josef, Muma, Charles F.
• Application Number:
  US11/345,884
• Publication Number:
  US 20060202798A1
• Time in Patent Office: Days
• US Class Current: 340/5.610
• CPC Class Codes: B60R 25/2072 with means for preventing jamming or interference of a remote switch control signal
• CPC Class Codes: B60R 25/24 using electronic identifiers containing a code not memorised by the user
• CPC Class Codes: G07C 2009/00793 by Hertzian waves
• CPC Class Codes: G07C 2209/61 Signal comprising different frequencies, e.g. frequency hopping
• CPC Class Codes: G07C 9/00309 operated with bidirectional data transmission between data carrier and locks
• CPC Class Codes: G08C 25/00 Arrangements for preventing or correcting errors; Monitoring arrangements

Abstract

A passive start and entry system (PASE) monitors several RF frequencies to detect a fob signal and for noise at each of the several frequencies. When the PASE system detects noise on the default frequency another RF channel is selected for communication. A vehicle unit sends a signal to a fob indicating which frequency the fob should use to transmit. The fob resets an RF sender to the selected frequency. At the same time the vehicle unit resets the RF receiver to receive on that frequency.

Claims

1. A passive start and entry system comprising:

a vehicle unit for scanning a plurality of RF channels; and

a fob having an LF channel receiver to receive a communication from said vehicle unit and a RF channel sender to return a communication to said vehicle unit using one of said plurality of RF channels.

2. The system of claim 1, wherein said vehicle unit includes a signal strength indicator to scan said plurality of RF channels and determine a selected RF channel.

3. The system of claim 1, wherein said RF channel sender includes multiple RF channels.

4. The system of claim 2, wherein said selected RF channel is said channel having said least interference.

5. The system of claim 2, wherein said selected RF channel comprises said default channel.

6. The system of claim 1, wherein said vehicle unit includes an LF channel sender to send a communication to said fob and multiple RF channel receivers to receive a communication from said fob on one of said plurality of RF channels.

7. A method of communication for a vehicle passive entry and start system comprising:

a) scanning a plurality of RF channels using a vehicle receiver;

b) selecting one of the plurality of RF channels;

c) sending a signal to a fob using an LF channel; and

d) returning a signal to the vehicle receiver using the selected RF channel.

8. The method of claim 7, wherein said step a) includes initiating the scan by touching a door handle.

9. The method of claim 7, wherein said step a) includes initiating the scan at predetermined intervals of time.

10. The method of claim 7, wherein said step b) includes comparing the noise levels on each of the plurality of RF channels to one another.

11. The method of claim 10, wherein said step b) includes selecting the RF channel having the least amount of noise.

12. The method of claim 7, further including the step of:

setting the selected RF channel as a default transmission channel.

13. The method of claim 7, wherein said step d) includes setting an RF sender located in the fob to the selected RF channel and setting an RF receiver located in the vehicle unit to the selected RF channel.

14. A method of communication for a vehicle passive entry and start system comprising:

a) scanning a default RF channel using a vehicle receiver;

b) comparing the noise level on the default RF channels to a predetermined threshold level;

c) selecting one of a plurality of RF channels based upon said step b)

d) sending a signal to a fob using an LF channel; and

e) returning a signal to the vehicle receiver using the selected RF channel.

15. The method of claim 14, wherein said step a) includes initiating the scan by touching a door handle.

16. The method of claim 14, wherein said step a) includes initiating the scan at predetermined intervals of time.

17. The method of claim 14, wherein said step c) includes comparing the noise levels on each of the plurality of RF channels to one another.

18. The method of claim 17, wherein said step c) includes selecting the RF channel having the least amount of noise.

19. The method of claim 14, including the step of:

setting the selected RF channel as a default transmission channel.

20. The method of claim 14, wherein said step e) includes setting an RF sender located in the fob to the selected RF channel and setting an RF receiver located in the vehicle unit to the selected RF channel.