Remote keyless entry system with two-way long range communication

• US 20060077037A1
• Filed: 10/07/2004
• Published: 04/13/2006
• Est. Priority Date: 10/07/2004
• Status: Active Grant

• Current Assignee: Lear Corporation
• Original Assignee: Lear Corporation
• Inventors: Ghabra, Riad, Luo, Yi, Tang, Qingfeng
• Granted Patent: US 8,026,793 B2
• Time in Patent Office: Days
• US Class Current: 340/5.720
• 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 2209/62 Comprising means for indicating the status of the lock
• CPC Class Codes: G07C 9/00309 operated with bidirectional data transmission between data carrier and locks
• CPC Class Codes: H04B 1/04 Circuits

Abstract

Vehicle information (e.g., status information, calibratable parameters, or diagnostic data) is transmitted from a base station mounted in a vehicle to a portable RKE fob via a radio-frequency signal within a specified average field strength limit. A multi-byte vehicle message is formed and then coded into a multi-bit coded message. The multi-bit coded message is framed into a plurality of packets. The radio-frequency signal is wirelessly transmitted from the base station with a plurality of spaced packet windows having a predetermined duty cycle, each packet window including a respective one of the plurality of packets. The radio-frequency signal within each of the packet windows has a predetermined field strength greater than the average field strength limit and a substantially zero field strength between the packet windows. The predetermined duty cycle results in an actual average field strength for transmitting all of the packets not exceeding the average field strength limit.

Claims

1. A method of transmitting vehicle information from a base station mounted in a vehicle to a portable RKE fob via a radio-frequency signal within a specified average field strength limit, said method comprising the steps of:

forming a multi-byte vehicle message;

coding said vehicle message into a multi-bit coded message;

framing said multi-bit coded message into a plurality of packets;

wirelessly transmitting said radio-frequency signal from said base station with a plurality of spaced packet windows having a predetermined duty cycle, each packet window including a respective one of said plurality of packets, wherein said radio-frequency signal within each of said packet windows has a predetermined field strength greater than said average field strength limit and a substantially zero field strength between said packet windows, and wherein said predetermined duty cycle results in an actual average field strength for transmitting all of said packets not exceeding said average field strength limit;

receiving said plurality of packets within said portable RKE fob; and

recovering said vehicle message in response to said received plurality of packets.

2. The method of claim 1 wherein said radio-frequency signal is transmitted within a specified peak field strength limit which is a predetermined decibel level above said average field strength limit, and wherein said predetermined duty cycle corresponds to said predetermined decibel level.

3. The method of claim 2 wherein said predetermined duty cycle has a ratio of one-half of a packet window width to a packet period which is substantially equal to a reciprocal of a ratio of said peak field strength limit to said average field strength limit.

4. The method of claim 3 wherein a ratio of said packet window width to said packet period is about one tenth.

5. The method of claim 1 wherein said vehicle message includes data indicative of a security alarm status.

6. The method of claim 1 wherein said vehicle message includes data indicative of a vehicle lock status.

7. The method of claim 1 wherein said vehicle message includes data indicative of a vehicle temperature status.

8. The method of claim 1 wherein said vehicle message includes data identifying said portable RKE fob for which said vehicle message is intended.

9. The method of claim 1 wherein said vehicle message is transmitted by said base station in response to a request message transmitted by said portable RKE fob.

10. The method of claim 9 wherein said vehicle message includes data identifying said portable RKE fob for which said vehicle message is intended, and wherein said data identifying said portable RKE fob is comprised of an identifying number previously transmitted from said portable RKE fob to said vehicle transmitter in said request message.

11. The method of claim 10 wherein said identifying number is generated as a random number by said portable RKE fob.

12. The method of claim 1 wherein a fob message is transmitted from said portable RKE fob to said base station according to the steps of:

coding said fob message into a multi-bit coded fob message;

framing said multi-bit coded fob message into a plurality of packets;

wirelessly transmitting a radio-frequency fob signal from said portable RKE fob with a plurality of spaced packet windows having said predetermined duty cycle, each packet window including a respective one of said plurality of packets, wherein said radio-frequency fob signal within each of said packet windows has said predetermined field strength greater than said average field strength limit and a substantially zero field strength between said packet windows, and wherein said predetermined duty cycle results in an actual average field strength for transmitting all of said packets not exceeding said average field strength limit.

13. A vehicle base station in a vehicle for wirelessly transmitting a radio-frequency signal to a portable fob, said radio-frequency signal being broadcast within a specified average field strength limit, said station comprising:

a message controller for forming a multi-byte vehicle message, coding said vehicle message into a multi-bit coded message, and framing said multi-bit coded message into a plurality of packets; and

a transceiver for wirelessly transmitting said radio-frequency signal from said base station with a plurality of spaced packet windows having a predetermined duty cycle, each packet window including a respective one of said plurality of packets, wherein said radio-frequency signal within each of said packet windows has a predetermined field strength greater than said average field strength limit and a substantially zero field strength between said packet windows, and wherein said predetermined duty cycle results in an actual average field strength for transmitting all of said packets not exceeding said average field strength limit.

14. The vehicle base station of claim 13 wherein said transceiver transmits said radio-frequency signal within a specified peak field strength limit which is a predetermined decibel level above said average field strength limit, and wherein said predetermined duty cycle corresponds to said predetermined decibel level.

15. The vehicle base station of claim 14 wherein said predetermined duty cycle has a ratio of one-half of a packet window width to a packet period which is substantially equal to a reciprocal of a ratio of said peak field strength limit to said average field strength limit.

16. The vehicle base station of claim 13 wherein said vehicle message includes data identifying said portable fob for which said vehicle message is intended.

17. A portable RKE fob for wirelessly receiving a radio-frequency signal broadcast from an RKE base station in a vehicle, wherein said radio-frequency signal encodes vehicle information, wherein said radio-frequency signal is broadcast as a plurality of packets within a plurality of spaced packet windows, wherein said radio-frequency signal has a predetermined field strength in each of said packet windows and has a substantially zero field strength between said packet windows, said spaced packet windows providing a predetermined duty cycle so that an average field strength for transmitting all of said packets falls within a specified average field strength limit, said portable RKE fob comprising:

a transceiver for wirelessly receiving said plurality of packets; and

a message controller for recovering said vehicle message by de-framing said plurality of packets into a multi-bit coded message, and decoding said multi-bit coded message into a multi-byte vehicle message; and

a display for displaying said vehicle information in response to said vehicle message.

18. The portable RKE fob of claim 17 further comprising a manually-activated control element, wherein said transceiver wirelessly transmits a status request message to said RKE base station in response to manual activation of said control element.

19. The portable RKE fob of claim 18 wherein said status request message includes an identifying number randomly generated by said portable RKE fob for being included in said vehicle message.

20. The portable RKE fob of claim 18 wherein said status request message is transmitted by coding said status request message into a multi-bit coded request message, framing said multi-bit coded request message into a plurality of request packets, and wirelessly transmitting a radio-frequency fob signal from said portable RKE fob with a plurality of spaced packet windows having said predetermined duty cycle, each packet window including a respective one of said plurality of request packets, wherein said radio-frequency fob signal within each of said packet windows has said predetermined field strength greater than said average field strength limit and a substantially zero field strength between said packet windows, and wherein said predetermined duty cycle results in an actual average field strength for transmitting all of said packets not exceeding said average field strength limit.