Adaptive decode strategy for remote keyless entry and tire pressure monitoring system

• US 20070046447A1
• Filed: 09/01/2005
• Published: 03/01/2007
• Est. Priority Date: 09/01/2005
• Status: Active Grant

• Current Assignee: Schrader Electronics Incorporated (Sensata Technologies Holding Plc)
• Original Assignee: Lear Corporation
• Inventors: Nantz, John, Conner, Bruce, Kovac, Zoran
• Granted Patent: US 7,414,522 B2
• Time in Patent Office: Days
• US Class Current: 340/426.330
• CPC Class Codes: B60C 23/0408 transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver
• CPC Class Codes: B60C 23/0462 Structure of transmission protocol
• CPC Class Codes: B60R 25/24 using electronic identifiers containing a code not memorised by the user

Abstract

A system and method for decoding signals from a tire pressure monitoring (TPM) system and a remote keyless entry (RKE) system includes determining a signal strength of the signal. The method also includes evaluating at least a first bit and the signal strength of the signal. The method further includes determining a first bit threshold based on the evaluated first bit and the signal strength. The method includes storing the first data bit threshold in a memory of the controller and determining a logic state of a second bit of a signal based on the first data bit threshold.

Claims

1. A method for decoding a signal having a plurality of bits, through the use of a controller, wherein the signal is generated by a tire pressure monitoring (TPM) system and/or a remote keyless entry (RKE) system, the method comprising:

determining a signal strength of the signal;

evaluating at least a first bit and the signal strength of the signal;

determining a first data bit threshold based on the first bit and the signal strength;

storing the first data bit threshold in a memory of the controller; and

determining a logic state of a second bit of the signal based on the first data bit threshold.

2. A method according to claim 1, wherein the logic state of the second bit includes the second bit being a logic zero or a logic one.

3. A method according to claim 1, wherein evaluating at least the first bit and the signal strength of the signal includes measuring at least the first bit and the signal strength of the signal.

4. A method according to claim 3, wherein measuring at least the first bit includes measuring bits of a preamble section and a header section of the signal.

5. A method according to claim 1, wherein the second bit is a bit within a data section of the signal.

6. A method according to claim 1, wherein determining the logic state of the second bit of the signal based on the first data bit threshold includes determining a second data bit threshold based on the first bit;

and

storing the second data bit threshold in the memory of the controller.

7. A method according to claim 1, wherein determining the signal strength of the signal includes generating a received signal strength indicator (RSSI) signal.

8. A method according to claim 1, wherein determining the signal strength of the signal includes measuring a variance in pulse width between the plurality of bits.

9. A method according to claim 1, wherein storing the first data bit threshold in a memory of the controller includes storing the first data bit within a look-up table located within the memory of the controller.

10. A vehicle system for decoding a signal having a plurality of bits, through the use of a controller, wherein the signal is generated by a tire pressure monitoring (TPM) system and/or a remote keyless entry (RKE) system, the system being configured to:

determine a signal strength of the signal;

evaluate at least a first bit and the signal strength of the signal;

determine a first data bit threshold based on the evaluated first bit and the signal strength;

store the first data bit threshold in a memory of the controller; and

determine a logic state of a second bit of the signal based on the first data bit threshold.

11. A system according to claim 10, wherein the system being configured to evaluate at least the first bit and the signal strength of the signal includes measuring at least the first bit and the signal strength of the signal.

12. A system according to claim 11, wherein the system being configured to measure at least the first bit includes measuring bits of a preamble section and a header section of the signal.

13. A system according to claim 10, wherein the second bit is a bit within a data section of the signal.

14. A system according to claim 10, wherein the system being configured to determine the logic state of the second bit of the signal based on the first data bit threshold includes the system being configured to:

determine a second data bit threshold based on the evaluated first bit; and

store the second data bit threshold in the memory of the controller.

15. A system according to claim 10, wherein the system being configured to determine the signal strength of the signal includes the system being configured to generate a received signal strength indicator (RSSI) signal.

16. A system according to claim 10, wherein the system being configured to determine the signal strength of the signal includes the system being configured to measure a variance in pulse width between the plurality of bits.

17. A system according to claim 10, wherein the system being configured to store the first data bit threshold in a memory of the controller includes storing the first data bit threshold within a look-up table located within the memory of the controller.

18. A method for decoding a signal having a plurality of bits, through the use of a controller, wherein the signal is generated by a tire pressure monitoring (TPM) system and a remote keyless entry (RKE) system, the method comprising:

receiving the signal having the plurality of bits, wherein the plurality of bits have a format that includes a preamble section, a header section, and a data section;

generating a received signal strength indicator (RSSI) signal based on the signal;

measuring bits of the preamble section and the header section;

determining a first data bit threshold based on the measured preamble section bits and the header section bits;

storing the first data bit threshold in a look-up table of the controller;

measuring a first data bit of the data section; and

comparing the measured first data bit to the first data bit threshold; and

determining a logic state of the first data bit based on the comparison between the measured first data bit and the first data bit threshold.

19. A method according to claim 18, further comprising:

determining a second data bit threshold based on the first data bit threshold and the logic state of the first data bit;

measuring a second data bit;

comparing the measured second data bit to the second data bit threshold;

determining a logic state of the second data bit based on the comparison between the measured second data bit and the second data bit threshold; and

storing the second data bit threshold in the look-up table of the controller.