Multiple transceiver synchronous communication system

• US 8,193,915 B2
• Filed: 03/06/2008
• Issued: 06/05/2012
• Est. Priority Date: 03/06/2008
• Status: Expired due to Fees

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: McCall, Clark E., Proefke, David T., Biondo, William A.
• Primary Examiner(s): Bugg, George
• Assistant Examiner(s): OBINIYI, PAULSON IDOWU
• Application Number:
  US12/043,732
• Publication Number:
  US 20090224876A1
• Time in Patent Office: 1,552 Days
• Field of Search: 340/5.61, 340/7.38, 340/426.36, 340/426.35, 340/5.63, 340/7.37, 340/10.34, 340/10.33, 340/10.4, 340/10.3, 340/10.1
• US Class Current: 340/10.34
• CPC Class Codes: B60R 25/2009 Antitheft state indicator
• CPC Class Codes: B60R 25/24 using electronic identifiers containing a code not memorised by the user
• CPC Class Codes: B60R 25/403 Power supply in the vehicle
• CPC Class Codes: G07C 2009/00587 by battery
• CPC Class Codes: G07C 2009/00793 by Hertzian waves
• CPC Class Codes: G07C 9/00309 operated with bidirectional data transmission between data carrier and locks

Abstract

A vehicle transceiver module is provided for use in a synchronous communication system including the vehicle transceiver module and one or more key fobs, each of the key fobs including a key fob transceiver for transmitting and receiving signals. The vehicle transceiver module includes transceiver circuitry, a controller, a storage device and power control circuitry. The transceiver circuitry receives the signal transmitted by the key fob transceiver and provides it to the controller. The controller is coupled to the transceiver for determining an offset value associated with one of the key fobs in response to an offset time duration between a reception time of the signal from the key fob and a first expected reception time of the signal from the key fob. The storage device is coupled to the controller for receiving the offset value associated with the key fob from the controller and stores the offset value along with information identifying the key fob. The power control circuitry is coupled to the transceiver circuitry for providing operational power thereto. In addition, the controller is also coupled to the power control circuitry and provides a begin transmission signal thereto to power up the transceiver circuitry for transmission of a signal to the key fob at a transmission start time determined by the controller in response to the offset value associated with the key fob and a second expected reception time.

Claims

1. A method for providing power conservation in a first transceiver in synchronous communication with a second transceiver, the method comprising the steps of:

determining an offset value for the second transceiver in response to an offset time duration between a reception time of a signal from the second transceiver and a first expected reception time of the signal from the second transceiver;

storing the offset value along with information identifying the second transceiver; and

powering up the first transceiver for transmission of a signal to the second transceiver at a transmission start time determined in response to the offset value and a second expected reception time.

2. The method in accordance with claim 1 further comprising the step of powering down the first transceiver at a transmission stop time determined in response to the transmission start time and a transmission time duration.

3. The method in accordance with claim 2 wherein the step of storing the offset value along with the information identifying the second transceiver further comprises the step of storing the first expected reception time as a last reception time of the signal from the second transceiver, and wherein the step of powering down the first transceiver comprises the steps of:

calculating the transmission time duration in response to the last reception time of the signal from the second transceiver and the second expected reception time of the signal from the second transceiver; and

powering down the first transceiver at the transmission stop time determined in response to the transmission start time and the transmission time duration.

4. The method in accordance with claim 1 wherein the second transceiver is one of a plurality of second transceivers, the method comprising the steps of:

determining a plurality of offset values, each of the plurality of offset values corresponding to one of the plurality of second transceivers and each of the plurality of offset values determined in response to the offset time duration between a reception time of a signal from a corresponding one of the plurality of second transceivers and the first expected reception time of a most recent reception of the signal from the corresponding one of the plurality of second transceivers;

storing each of the plurality of offset values along with transceiver identification information identifying the corresponding one of the plurality of second transceivers corresponding thereto; and

powering up the first transceiver for transmission of a signal to one or more of the plurality of second transceivers at the transmission start time determined in response to all of the plurality of offset values and the second expected reception time.

5. The method in accordance with claim 4 further comprising the steps of:

calculating a transmission time duration in response to all of the plurality of offset values; and

powering down the first transceiver at a transmission stop time determined in response to the transmission start time and the transmission time duration.

6. The method in accordance with claim 5 wherein the step of storing each of the plurality of offset values comprises the step of storing each of the plurality of offset values along with the transceiver identification information identifying the corresponding one of the plurality of second transceivers corresponding thereto and a last reception time for a signal received from the corresponding one of the plurality of second transceivers, the last reception time identifying the first expected reception time of the signal from the corresponding one of the plurality of second transceivers when the signal was last received from the corresponding one of the plurality of second transceivers, and wherein the step of calculating the transmission time duration comprises the step of calculating the transmission time duration in response to all of the plurality of offset values, the last reception time of all of the plurality of second transceivers and the second expected reception time.

7. The method in accordance with claim 1 wherein the step of storing the offset value comprises the step of storing the offset value at a predetermined location in a storage device associated with the second transceiver, overwriting the offset value previously stored therein.

8. The method in accordance with claim 1 wherein the step of storing the offset value comprises the step of storing the offset value as one of multiple offset values associated with the second transceiver wherein an immediately previous offset value is stored as another one of the multiple offset values associated with the second transceiver.

9. The method in accordance with claim 8 wherein the step of powering up the first transceiver comprises the step of powering up the first transceiver for transmission of the signal to the second transceiver at the transmission start time, wherein the transmission start time is determined in response to the second expected reception time and a difference between the offset value and the immediately previous offset value.

10. The method in accordance with claim 9 wherein the step of storing the offset value as one of the multiple offset values associated with the second transceiver comprises the step of storing the first expected reception time as a reception time of the signal from the second transceiver associated with the offset value, the method further comprising the steps of:

calculating a transmission time duration in response to the reception time of the signal from the second transceiver associated with the offset value stored immediately prior to the second expected reception time of the signal from the second transceiver and the second expected reception time; and

powering down the first transceiver at a transmission stop time determined in response to the transmission start time and the transmission time duration.

11. A vehicle transceiver module for use in a synchronous communication system including the vehicle transceiver module and one or more key fobs, each of the one or more key fobs including a key fob transceiver for transmitting a signal, the vehicle transceiver module comprising:

transceiver circuitry for transmitting a signal to the key fob transceiver and for receiving the signal transmitted by the key fob transceiver;

a controller coupled to the transceiver circuitry for determining an offset value associated with one of the one or more key fobs in response to an offset time duration between a reception time of the signal from the one of the one or more key fobs and a first expected reception time of the signal from the one of the one or more key fobs;

a storage device coupled to the controller and storing the offset value along with information identifying the one of the one or more key fobs associated therewith; and

power control circuitry coupled to the transceiver circuitry for providing operational power thereto, wherein the controller is also coupled to the power control circuitry and provides a begin transmission signal to the power control circuitry to power up the transceiver circuitry for transmission of the signal to one of the one or more key fobs at a transmission start time determined by the controller in response to the offset value associated with the one of the one or more key fobs and a second expected reception time.

12. The vehicle transceiver module in accordance with claim 11 wherein the controller provides an end transmission signal to the power control circuitry to power down the transceiver circuitry for power conservation at a transmission stop time determined in response to the transmission start time and a transmission time duration.

13. The vehicle transceiver module in accordance with claim 11 wherein the controller calculates a transmission time duration in response to two or more offset values stored in the storage device, each of the two or more offset values being associated with different ones of the one or more key fobs and provides an end transmission signal to the power control circuitry to power down the transceiver circuitry for power conservation at a transmission stop time determined in response to the transmission start time and the transmission time duration.

14. The vehicle transceiver module in accordance with claim 13 wherein the controller calculates the transmission time duration in response to all of the two or more offset values stored in the storage device.

15. The vehicle transceiver module in accordance with claim 14 wherein the storage device stores a last reception time of the signal from each of the one or more key fobs in response to receiving the first expected reception time of the signal from one of the one or more key fobs from the controller when the signal was last received from the one of the one or more key fobs, the storage device storing the last reception time along with the offset value associated with the one of the one or more key fobs and the information identifying the one of the one or more key fobs, and wherein the controller calculates the transmission time duration in response to all of the two or more offset values, the last reception time associated with all of the one or more key fobs and the second expected reception time.

16. The vehicle transceiver module in accordance with claim 11 wherein the storage device, when receiving the offset value associated with the one of the one or more key fobs from the controller for storing therein, stores the offset value as one of multiple offset values associated with the one of the one or more key fobs, an immediately previous offset value being stored as another one of the multiple offset values associated with the one of the one or more key fobs, and wherein the controller calculates the transmission start time in response to the second expected reception time and a difference between the offset value and the immediately previous offset value.

17. The vehicle transceiver module in accordance with claim 16 wherein the storage device when receiving the offset value for storage therein also receives the first expected reception time from the controller for storing therein, the storage device storing the first expected reception time as a reception time of the signal from the one of the one or more key fobs associated with the offset value being stored in the storage device, and wherein the controller calculates a transmission time duration in response to the reception time of the signal from the one of the one or more key fobs associated with the offset value stored immediately prior to the second expected reception time of the signal from the one of the one or more key fobs and the second expected reception time and provides an end transmission signal to the power control circuitry to power down the transceiver circuitry for power conservation at a transmission stop time determined in response to the transmission start time and the transmission time duration.

18. A key fob for two-way communication with a vehicle transceiver module including a vehicle transceiver for transmitting a first radio frequency (RF) signal, the key fob comprising:

transceiver circuitry for receiving the first RF signal transmitted by the vehicle transceiver and for transmitting a second RF signal to the vehicle transceiver;

power control circuitry coupled to the transceiver circuitry for providing operational power thereto in response to receiving a transceiver power control signal;

a motion detection device for generating a motion detected signal in response to detecting movement of the key fob; and

a controller coupled to the motion detection device and the power control circuitry for providing the transceiver power control signal to the power control circuitry only within a predetermined time period after receiving the motion detected signal from the motion detection device.

19. The key fob in accordance with claim 18 wherein the predetermined time period is defined in accordance with a software configurable value.

20. The key fob in accordance with claim 18 wherein the predetermined time period is ten hours.