Optimisation of wireless communications of a tyre-pressure-monitoring system for a motor vehicle

1. A method for adjusting the reaction time of wireless communications between a tire pressure monitoring system of a motor vehicle and a smart device of a user of said motor vehicle, said tire pressure monitoring system comprising a plurality of units including a central unit and a plurality of wheel units, said communications taking place between said units of said tire pressure monitoring system and said smart device by means of ultra high frequency signals in which, in a given period, phases permitting the activation of two-way communications alternate with standby phases, said method comprising:

when the smart device is located in a first area of the environment of the vehicle and approaches the vehicle, the central unit sets the period of wireless communications between the units of the tire pressure monitoring system and with the smart device to a first given value;

when the smart device is located in a second area of the environment of the vehicle, nearer to the vehicle than the first area, the central unit establishes a connection using two-way wireless communications between said central unit and the smart device, and:

if the smart device is moving in the second area, the central unit sets the period of wireless communications between the wheel units of the tire pressure monitoring system and the smart device to a second given value, lower than the first given value; or

if the smart device is stationary in the second area for a period that exceeds a specified threshold, the central unit causes the wheel units of the tire pressure monitoring system to switch to a standby phase only.

2. The method as claimed in claim 1 , wherein the first area is an area covered by a network using ultra high frequency radio waves, with a frequency exceeding 1 gigahertz, said network being a Wifi or 4G network.

3. The method as claimed in claim 1 , wherein the second area is an area covered by the range of ultra high frequency radio waves, having a frequency of more than 1 GHz, from the units of the tire pressure monitoring system, said range corresponding to the range of a Bluetooth® or Bluetooth® Low Energy signal from said units of the tire pressure monitoring system.

4. The method as claimed in claim 1 , wherein, when the smart device is located in a first area of the environment of the vehicle, the method further comprises the collecting and updating by the central unit of information relating to the tires received from the wheel units and the transmission of this information to the smart device.

5. The method as claimed in claim 1 , wherein, when the smart device is located in the first area of the environment of the vehicle, the central unit also uses information concerning the habits of the user of the vehicle associated with the smart device, stored in a memory of a unit of the tire pressure monitoring system, to initiate the setting of the period of the wireless communications between the wheel units of the tire pressure monitoring system and the smart device to a first given value.

6. The method as claimed in claim 1 , wherein the first value of the wireless communications period is between 1 and 5 seconds.

7. The method as claimed in claim 1 , wherein the second value of the wireless communications period is between 20 and 200 milliseconds.

8. The method as claimed in claim 1 , wherein the distance between the vehicle and the smart device and/or the movement of the smart device, in the first and second areas, are determined by the central unit of the tire pressure monitoring system, for example by using the GPS coordinates of the central unit and of the smart device, by measuring the power of the signal transmitted by the smart device and received by the central unit, or by using at least one accelerometer incorporated into the smart device.

9. The method as claimed in claim 8 , wherein information concerning the distance between the vehicle and the smart device and/or the movement of the smart device is determined by the central unit and is retrieved by a computing cloud, which controls the central unit on the basis of said information.

10. The method as claimed in claim 1 , wherein the smart device is included in the set comprising a smartphone, a tablet and a smart watch.

11. A central unit of a tire pressure monitoring system of a motor vehicle, said tire pressure monitoring system comprising a plurality of units including said central unit and a plurality of wheel units, said communication taking place between said units of said tire pressure monitoring system and said smart device by ultra high frequency signals in which, in a given period, transmission phases alternate with standby phases, said central unit comprising means for implementing all the steps of the method as claimed in claim 1 .

12. A motor vehicle driver-assistance system comprising a central unit of a tire monitoring system of a motor vehicle according to the central unit as claimed in claim 11 .