WO2019086706A1

WO2019086706A1 - Self-powered low-energy wireless node, vehicle tire pressure monitoring system as well as method for transmitting tire pressure information

Info

Publication number: WO2019086706A1
Application number: PCT/EP2018/080320
Authority: WO
Inventors: Xing Ping Lin
Original assignee: Trw Automotive Electronics & Components Gmbh
Priority date: 2017-11-06
Filing date: 2018-11-06
Publication date: 2019-05-09

Abstract

Self-powered low-energy wireless node, vehicle tire pressure monitoring system as well as method for transmitting tire pressure information A self-powered low-energy wireless node for a vehicle tire pressure monitoring system is described, comprising an energy source, a power management and control module as well as a radio frequency transceiver configured to communicate with an associated component of the vehicle tire pressure monitoring system. The at least one self-powered low-energy wireless node is configured to extend the transmission range of the associated component of the vehicle tire pressure monitoring system. Furthermore, a vehicle tire pressure monitoring system and a method for transmitting tire pressure information are described.

Description

Self-powered low-energy wireless node, vehicle tire pressure monitoring system as well as method for transmitting tire pressure information

The invention provides a self-powered low-energy wireless node and a vehicle tire pressure monitoring system. In addition, the invention provides a method for transmitting tire pressure information wirelessly in an energy-efficient manner.

Vehicle tire pressure monitoring (TPM) systems typically include a TPM sensor inside each tire. Each TPM sensor includes a radio frequency (RF) transmitter for communicating with a vehicle-based receiver. The TPM sensor senses pressure in the tire and transmits a pressure information signal via its RF transmitter. The TPM receiver in the vehicle receives the RF pressure information signal and relays the information to a vehicle control module. When the pressure low, the vehicle will be alerted.

Additionally, in large truck applications, there is a challenge for the TPM receiver to pick up TPM sensors located far away, such as on trailer tires. The invention inter alia provides a self-powered low-energy wireless node for a vehicle tire pressure monitoring system, comprising an energy source, a power management and control module as well as a radio frequency transceiver configured to communicate with an associated component of the vehicle tire pressure monitoring system, wherein the at least one self-powered low-energy wireless node is configured to extend the transmission range of the associated component of the vehicle tire pressure monitoring system.

The invention further provides a vehicle tire pressure monitoring system with at least one tire pressure monitoring sensor, a central control module and at least one self-powered low-energy wireless node as mentioned above. The at least one tire pressure monitoring sensor is configured to transmit a transmission signal to the at least one self-powered low-energy wireless node. The self-powered low-energy wireless node is configured to forward the transmission signal received from the tire pressure monitoring sensor to the central control module. The self-powered low-energy wireless node is substantially a range extender for signal transmission of the tire pressure monitoring sensor as the working range of the tire pressure monitoring sensor is extended by the self-powered low-energy wireless node. In other words, the self-powered low-energy wireless node may receive a transmission signal transmitted by the tire pressure monitoring sensor and, further, the self-powered low-energy wireless node may forward or rather relay the transmission signal originally received from the tire pressure monitoring sensor.

The energy source may be established by a battery, in particular a small single coin cell battery.

An antenna may be assigned to the radio frequency transceiver so that signals can be received via the antenna. Further, signals may be transmitted via the antenna.

The self-powered low-energy wireless node may have a sleep mode, a learning and synchronization mode as well as a normal operation mode. The sleep mode has low power consumption so that the electrical energy of the energy source can be saved as much as possible. For instance, the node wakes up in the sleep mode periodically for checking for commands sent, but the node is powered off for long durations so as to save energy or rather reduce the power consumption. In fact, energy is preserved. The node has long polling cycles in its sleep mode. The self- powered low-energy wireless node may be operated in the sleep mode when the vehicle is parked. The node wakes up periodically (long off time to preserve the energy).

In the learning and synchronization mode, synchronization with other components of the system may take place. Particularly, the node is synchronized with the tire pressure monitoring sensor. The node is operated in the learning and synchronization mode when the vehicle starts motion or the ignition is turned on. In the learning and synchronization mode, the wireless node synchronizes with tire pressure monitoring sensor transmission timing. Thus, energy-efficient data exchange is ensured between the wireless node and the tire pressure monitoring sensor. In the normal operation mode, also called tire pressure monitoring (TPM) mode, a transmission signal shall be received that is transmitted by the remote located tire pressure monitoring sensor. The transmission signal sent by the tire pressure monitoring sensor may comprise tire pressure information, temperature information and/or timer calibration information.

In the normal operation mode, the wireless node wakes up periodically with timing matching the tire pressure monitoring sensor transmission schedule. It recalibrates the timer once a while.

In fact, the transmission signal is sent regularly once the tire pressure monitoring sensor is waked up. Hence, the synchronization may be done via the transmission signal due to the calibration information encompassed.

The at least one self-powered low-energy wireless node and the at least one tire pressure monitoring sensor may be synchronized with each other in the normal operation mode so that information can be submitted in an energy-efficient manner.

For instance, the self-powered low-energy wireless node is configured to automatically enter the learning and synchronization mode provided that no transmission signal is received in the normal operation mode.

The power management and control module may be configured to power on/off the self-powered low-energy wireless node at one or more defined times, in particular periodically and/or at predicted times. Hence, the power consumption can be reduced appropriately since the node is only operated at dedicated times.

The respective operation times may be pre-defined, in particular periodically.

Furthermore, the node may predict its operation times due to signals and/or information received, in particular from the tire pressure monitoring sensor.

Another aspect provides that the power management and control module is configured to adapt the one or more defined times. Thus, the times may be adjusted over time so as to take deviations into account. Those deviations may occur due to different temperatures, in particular different temperatures of the tire pressure monitoring sensor. In fact, the temperature may vary widely and so the sensor timing of the tire pressure monitoring sensor. According to an embodiment, the self-powered low-energy wireless node comprises a vibration sensor. The vibration sensor may be used to issue a trigger condition for waking up the node, namely stopping the sleep mode. The vibration sensor may be assigned to a vibration circuit. Generally, the vibration sensor may sense movement of the vehicle.

The self-powered low-energy wireless node may comprise a synchronizing timer for establishing a synchronized communication with a component of the vehicle tire pressure monitoring system, in particular a central control module of the vehicle tire pressure monitoring system. The synchronizing timer may be used to synchronize with the vehicle center control module. In case of several wireless nodes, all the wireless nodes will wake up at predetermined time(s) and listen the command from the vehicle center module. In this manner, more efficient information can be exchanged between the vehicle center control module and wireless nodes.

The synchronized communication between the center control module and the at least one wireless node can also be used for providing information with regard to the vehicle condition. For instance, the center control module will inform the wireless node vehicle is moving or not so the wireless node can be operating in different mode to save energy. Hence, no separately formed vibration sensor is necessary.

The at least one tire pressure monitoring sensor may be configured to transmit the transmission signal periodically. The transmission signal may be used for providing tire pressure information, e.g. every minute. In addition, the transmission signal can be used for synchronizing the tire pressure monitoring sensor and the wireless node.

According to an embodiment, a plurality of self-powered low-energy wireless nodes are provided that are positioned in a certain pattern, wherein the vehicle tire pressure monitoring system is configured to determine the location of the at least one tire pressure monitoring sensor with regard to the vehicle by evaluating the forwarded transmission signals. In general, it is desirable to identify which tire has low pressure, given that the tire positions are rotated routinely. For instance, the at least one wireless node receives some or all transmission signals of the tire pressure monitoring sensors. By properly arranging the locations of the wireless nodes, the system can identify the location of the sensors and associate them with a tire location on the vehicle.

Moreover, the vehicle tire pressure monitoring system may have a sleep mode, a learning and synchronization mode as well as a normal operation mode. In the sleep mode, the wireless node has a long polling cycle whereas the sensor does not send any information.

A trigger condition wakes the center control module as well as the sensor up. The sensor automatically enters the learning and synchronization mode in which information for synchronizing is transmitted. The center control module issues a command to the wireless node to put it into its respective learning and synchronization mode in which the wireless node synchronized with the sensor.

In the normal operation mode, the wireless node has wake up times being synchronized with the sensor which has been done in the learning and synchronization modes. Furthermore, a method for transmitting tire pressure information wirelessly in an energy-efficient manner is provided by using a vehicle tire pressure monitoring system, with the following steps:

Sensing tire pressure information via at least one tire pressure monitoring sensor, - Transmitting the tire pressure information sensed to at least one self- powered low-energy wireless node via the at least one tire pressure monitoring sensor, and

Forwarding the tire pressure information sensed to a central control module via the at least one self-powered low-energy wireless node. According to an aspect, the vehicle tire pressure monitoring system is waked up by a trigger condition, in particular by a vehicle motion and/or an ignition start.

Furthermore, the at least one tire pressure monitoring sensor and the at least one self-powered low-energy wireless node may be synchronized prior to the transmitting step by operating the self-powered low-energy wireless node and/or the tire pressure monitoring sensor in a learning and synchronization mode, in particular wherein the tire pressure monitoring sensor and the self-powered low- energy wireless node synchronize with each other when both are operated in their respective learning and synchronization mode, further particularly both are operated in their respective normal operation mode after completion of the synchronization.

The learning and synchronization mode of the self-powered low-energy wireless node may be initiated by the center control module issuing a synchronize command.

The learning and synchronization mode of the tire pressure monitoring sensor may be initiated by a trigger condition.

Another aspect provides that the self-powered low-energy wireless node is powered on/off at predicted times which are obtained in the respective learning and synchronization mode and/or wherein the self-powered low-energy wireless node is powered on/off at defined times submitted by the tire pressure monitoring sensor.

In other words, a self-powered wireless node is implemented to improve the TPM RF link and help perform sensor auto-location, i.e., correlating a TPM RF pressure information signal with the tire location (e.g., front-left FL, front-right FR, rear-left RL, rear-right RR). The device is powered by a small energy source, for instance a battery cell, so that no connection to the vehicle power is required. It includes three/four main parts: battery, power management and control, vibration sensor (optional), and a RF transceiver.

Generally, the transmission range of the system is extended due to the self- powered low-energy wireless node(s). The power consumption of the self-powered low-energy wireless node(s) is minimized due to the synchronization. In fact, the self-powered low-energy wireless node(s) is/are synchronized with the TPM sensor(s) and/or the central control module so that the self-powered low-energy wireless node(s) is/are only powered on when signal transmission of the TPM sensor(s) and/or the central control module is expected or rather it is expected that the central control module is in its receiving mode.

In the sleep mode of the wireless node, the polling time is reduced so that the energy consumption is minimized. The foregoing aspects and many of the attendant advantages of the claimed subject matter will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein: - Figure 1 schematically shows a self-powered low-energy wireless node according to the invention,

Figure 2 schematically shows a vehicle tire pressure monitoring system according to the invention,

Figure 3 schematically shows a vehicle tire pressure monitoring system according to the invention,

Figure 4 shows a flow-chart illustrating a method for transmitting tire pressure information wirelessly in an energy-efficient manner by using a vehicle tire pressure monitoring system according to the invention,

Figure 5 shows an overview illustrating the different modes of the vehicle tire pressure monitoring system according to the invention,

Figure 6 shows a schematic time chart illustrating the method according to the invention using a vehicle tire pressure monitoring system according to the invention,

Figure 7 schematically illustrates one block of the normal operation mode, and

Figure 8 schematically illustrates n blocks of the normal operation mode.

In Figure 1 , a self-powered low-energy wireless node 10 is shown.

The self-powered low-energy wireless node 10 comprises an energy source 12, a power management and control module 14 as well as a radio frequency transceiver 16 connected to an antenna 18.

The node 10 can be implemented in a vehicle tire pressure monitoring system 20 shown in Figure 2 that comprises several nodes 10, a central control module 22 connected with a control module antenna 24 as well as tire pressure monitoring (TPM) sensors 24 assigned to the tires of the vehicle equipped with the tire pressure monitoring system 20.

Generally, each node 10 is configured to communicate with an associated component of the vehicle tire pressure monitoring system 12 via the radio frequency transceiver 18, namely the TPM sensor(s) 24 as well as the central control module 22 as will be explained later.

Therefore, the self-powered low-energy wireless node 10 is generally configured to extend the transmission range of the associated component of the vehicle tire pressure monitoring system 12. In the tire pressure monitoring (TPM) application, the power management component, namely the power management and control module 14, is powered on/off at one or more certain pre-arranged times as shown in Figure 6 to which reference is made later.

Since the node10 is not required to be connected to the vehicle. The node 10 can be applied anywhere in the vehicle as shown in Figure 2.

In the shown embodiment, there are four wireless nodes 10 distributed about the vehicle which, in this case, is a truck with an attached trailer. Even though not shown in Figure 2, each tire of the vehicle can have associated with it a TPM sensor 24. In this implementation, each wireless node 10 can receive some or all TPM sensor transmissions, namely transmission signals of one or all TPM sensors 24.

For instance, one of the wireless nodes 10 is located at the rear of the vehicle, e.g., on the back of the trailer, to cover the rear tire sensors' transmissions and some or all transmissions from the rest of the TPM sensors 24. This wireless node 10 receives the signal from the rear tire and relays the information back to the central control module 20. In this manner, this wireless node 10 expands the system range.

Additionally, by properly arranging the locations of the wireless nodes 10, the system 20 can identify the location of the TPM sensors 24 with respect to the vehicle and associate them with a tire location on the vehicle. The one main challenge for this arrangement is how to minimize the power consumption so the energy source 12, for instance a small single coin cell battery, can last a long life, such as 10 years.

Each TPM sensor 24 transmits periodically to inform the vehicle the tire pressure information. For example, it transmits every 1 minute.

This timing is controlled by a TPM sensor timer that may be integrated in each TPM sensor 24.

The wireless nodes 10 need to be awake during this transmission in order to receive and process the transmission signal sent by the respective TPM sensor 24.

Ideally, the wireless nodes 10 and TPM sensors 24 are synchronized so that the wireless nodes 10 are on only when the TPM sensors 24 are transmitting. Synchronizing this timing is, however difficult.

It is very often that the TPM sensor timer is part of its RC circuit and is executed during the polling mode of the TPM sensor 24.

The timer accuracy is dependent on the tolerance of the component and also the temperature in the application. The temperature can vary widely and, therefore, so can the TPM sensor timing. The timing can be calibrated by implementing a more accurate clock, such as a crystal, in the TPM sensor 24 so as to help minimize power consumption.

To save the energy, the wireless node 10 needs to be powered on and off and stay off as long as possible.

So, we the wireless node 10 is configured to track and calibrate when to expect TPM sensor transmissions, namely signal transmissions of the respective TPM sensor 24, in a highly accurate manner. In this manner, the wireless node 10 will try to be on for a short time as possible, and yet still receive the TPM sensor signal, namely the transmission signal.

The system 20 may have an initial learning mode that is illustrative shown in Figure 5. In the initial learning mode, the node 10 will enter into this learning mode if the wireless node 10 hasn't received a TPM sensor transmission in certain window, namely a transmission signal of the TPM sensor 24. In this initial learning mode, the wireless node 10 will be on more frequently and so it can capture the new TPM sensor transmission, namely the next transmission signal.

Based on the timing of the TPM sensor transmission and temperature information, the wireless node 10 can register each sensor clock characteristics at different temperatures, namely the ones of the TPM sensor timer being part of the TPM sensor 24. Since the change in the sensor timing clock due to temperature has a uniform, constant pattern, the learned information can be used for estimation of the timing of the TPM sensor future transmission(s).

Once the wireless node 10 has learned the timing of the TPM sensor future transmission(s), the wireless node 10 will wake up at the predicted time to capture the sensor transmission, namely the transmission signals.

This predicted time is adaptive over time and calibrated each time or periodically.

In this way, more accurate timing can be predicted and it reduces the wireless node 10 on time so that the power consumption is reduced. At the TPM sensor side, it can also send the timer calibration results out along with the pressure and temperature information.

As shown in Figure 1 , the wireless node 10 can include a vibration sensor 26 or rather a vibration circuit for sensing movement of the vehicle so that the wireless node 10 can be in different modes when driving versus parking modes. The wireless node 10 can also have another timer, also called synchronizing timer, to synchronize with the vehicle center control module 20. Hence, a synchronized communication channel 28 may be established as indicated in Figure 3.

All the wireless nodes 10 will be waked up at a predetermined time(s) and listen the command from the vehicle center module 20 as shown in Figure 6. In this manner, more efficient information can be exchanged between the vehicle center control module 20 and the wireless nodes 10.

The synchronized communication 28 between the center control module 20 and wireless nodes 10 can also be used for the center control module 20 to inform the wireless node 10 the vehicle condition as also illustrated in Figure 3.

To reduce the cost, the vibration sensor can be taken off. In fact, advantage is taken of the synchronized center control module 20 and wireless nodes 10, namely the synchronized communication 28.

The center control module 20 will inform the wireless node 10 whether vehicle is moving or not so the wireless node 10 can be operating in different mode to save energy.

Generally, the distributed wireless nodes 10 demand less the power from the TPM sensor 24 so that the TPM sensor 24 can be lighter and cheaper.

The calculation and calibration of the TPM sensor timer can be also carried out at the center module side, namely the center control module 20, to save the power consumption on the TPM sensor side.

As already mentioned, there are basically three different operation modes for the wireless nodes 10 as well as the whole system 20 as also illustrated in Figure 5. Sleep mode: when the vehicle is parked. It wakes up periodically (long off time to preserve the energy)

Learning and synchronization mode: when the vehicle starts motion or the ignition is turned on. The wireless node synchronized with TPM sensor transmission timing Normal TPM operation mode: the wireless node wakes up periodically with timing matching the TPM sensor transmission schedule. It recalibrates the timer once a while.

In Figure 4, the method is illustrated illustratively according to which the system 20 changes its respective operation modes. In Figure 6, the respective steps are also shown wherein the signal exchange is illustrated. Accordingly, Figures 4 to 6 illustrate the different operation modes of the system 20, in particular the different operation modes of the respective components and how the components communicate with each other.

As shown, each wireless node 10 has a long polling cycle in its sleep mode. Once a trigger condition occurs, the system 20 wakes up. For instance, an acceleration of the vehicle is the respective trigger condition that might be sensed by the vibration sensor 26 or rather the central control module 20 as shown in Figure 6.

The moving vehicle also wakes up the respective TPM sensor(s) 26 as shown in Figure 6.

The central control module 20 issues a command to trigger communication with the respective wireless node 10 as shown in Figure 6.

Once the communication between the central control module 20 and the respective wireless node 10 is synchronized (command synchronized), the wireless node 10 is operated in its learning and synchronization mode as shown in Figure 6. Further, the central control module 20 may be operated in its receiving mode as also shown in Figure 6.

In this mode, the wireless node 10 is on more frequently and so it can capture the new TPM sensor transmission, namely the next transmission signal of the TPM sensor 24, as shown in Figure 6.

The waked up TPM sensor 24 is directly operating in its learning and synchronization mode in which transmission signals may be sent more frequently so as to ensure fast synchronization with the wireless node 10.

Once the TPM sensor 24 and the wireless node 10 are synchronized, both are operated in their normal operation modes. The polling cycle of the wireless node 10 matches the transmission cycle of the TPM sensor 24 so that the respective communication is synchronized.

As shown in Figure 6, the transmission cycle Tx norm of the TPM sensor 24 in the normal operation mode is larger than the transmission cycle Tx sync in the learning and synchronization mode. Further, the polling cycle T norm of the wireless node 10 in the normal operation mode is shorter than the polling cycle T sleep in the sleep mode.

This generally ensures that the power consumption is minimized appropriately.

One block of the wireless node receiver on timing is shown in Figure 7 in the normal operation mode, namely the time when the wireless node 10 is ready for receiving a signal.

The wireless node 10 will be on for Rx on at the beginning and the end of each block. In this manner, the wireless node 10 will be guaranteed to receive one transmission frame of the TPM sensor 24 if the synchronization between the TPM sensor 24 and the wireless node 10 is within Tp rx window.

When a wireless node 10 repeat "n" blocks before going back to sleep, then the synchronization error between the wireless node 10 and the TPM sensor 24 can be expressed by n^*Rx_on. This is shown in Figure 8.

Assume a TPM sensor 24 transmits every minute a transmission signal Tx, wherein Tx=10ms and Tx_norm+Tx corresponds to 1 minute while Tx norm corresponds to the time between two transmission signals.

Tx_norm=1 minute-Tx=1 minute-10ms=1 minute

The allowed synchronization error between the wireless node 10 and the TPM sensor 24 is Tsync_window=nRx=nTd=n[mTx+(m-1 )Toff]

The ratio: Ratio=Tsync_window/Tx_norm determines the percentage error of the clock allowed, namely the percentage error of the synchronization, also called deviation.

For example, if n=3, m=8 (the TPM sensor 24 transmits 8 frames), Tx=10ms; Toff=1 10ms, then

Ratio=(Tsync_window)/(Tx_norm )=n[mTx+(m-1 )Toff]/(Tx_norm )=3[8χ 10+(8- 1 )1 10]/(60x 1000)=0.0425

Or the accepted sensor timer error percentage is Time_error=Ratio 100%=4.25%

Since the initial sensor clock timer error already be zeroed out during the wireless node's learning and synchronization processing and the time between a sensor message transmission is short, such as 1 minute, so only clock error from the sensor side would be oscillator frequency drift due to the temperature change over 1 minute interval time.

The 4% requirement in this example is very reasonable. It is quite feasible that the requirement could be less if the system 20 is recalibrated every time the wireless node 10 receiving the sensor information. In this manner, when the vehicle is in motion mode, the total on time during one wireless cycle period is

Node_on=(n+1 )xRx_on=(n+1 )x(2Tx+Toff)=4x(2x10+1 10)=520ms

The % on time for the wireless node 10 during normal TPM mode (vehicle in motion) is Rx_(duty_cycle )=Nodeon/(Tx(1 minute))=520/60000=0.008667=0.87%

When the vehicle in parking mode, the wireless node 10 will be in sleep mode and wake up to detect the center module signal once a while (much longer off time, for example: every 5 minutes). The duty cycle will be even lower.

Claims

1 . A self-powered low-energy wireless node for a vehicle tire pressure monitoring system, comprising an energy source, a power management and control module as well as a radio frequency transceiver configured to communicate with an associated component of the vehicle tire pressure monitoring system, wherein the at least one self-powered low-energy wireless node is configured to extend the transmission range of the associated component of the vehicle tire pressure monitoring system.

2. The self-powered low-energy wireless node according to claim 1 , wherein the self-powered low-energy wireless node has a sleep mode, a learning and synchronization mode as well as a normal operation mode.

3. The self-powered low-energy wireless node according to claim 2, wherein the self-powered low-energy wireless node is configured to automatically enter the learning and synchronization mode provided that no transmission signal is received in the normal operation mode.

4. The self-powered low-energy wireless node according to any of the preceding claims, wherein the power management and control module is configured to power on/off the self-powered low-energy wireless node at one or more defined times, in particular periodically and/or at predicted times.

5. The self-powered low-energy wireless node according to claim 4, wherein the power management and control module is configured to adapt the one or more defined times.

6. The self-powered low-energy wireless node according to any of the preceding claims, wherein the self-powered low-energy wireless node comprises a vibration sensor.

7. The self-powered low-energy wireless node according to any of the preceding claims, wherein the self-powered low-energy wireless node comprises a synchronizing timer for establishing a synchronized communication with a component of the vehicle tire pressure monitoring system, in particular a central control module of the vehicle tire pressure monitoring system.

8. A vehicle tire pressure monitoring system with at least one tire pressure monitoring sensor, a central control module and at least one self-powered low- energy wireless node according to any of the preceding claims, wherein the at least one tire pressure monitoring sensor is configured to transmit a transmission signal to the at least one self-powered low-energy wireless node, and wherein the self- powered low-energy wireless node is configured to forward the transmission signal received from the tire pressure monitoring sensor to the central control module.

9. The vehicle tire pressure monitoring system according to claim 8, wherein the at least one tire pressure monitoring sensor is configured to transmit the transmission signal periodically.

10. The vehicle tire pressure monitoring system according to claim 8 or 9, wherein a plurality of self-powered low-energy wireless nodes are provided that are positioned in a certain pattern, and wherein the vehicle tire pressure monitoring system is configured to determine the location of the at least one tire pressure monitoring sensor with regard to the vehicle by evaluating the forwarded transmission signals.

1 1 . The vehicle tire pressure monitoring system according to any of claims 8 to 10, wherein the vehicle tire pressure monitoring system has a sleep mode, a learning and synchronization mode as well as a normal operation mode.

12. A method for transmitting tire pressure information wirelessly in an energy- efficient manner by using a vehicle tire pressure monitoring system, with the following steps:

- Sensing tire pressure information via at least one tire pressure monitoring sensor, - Transmitting the tire pressure information sensed to at least one self- powered low-energy wireless node via the at least one tire pressure monitoring sensor, and

Forwarding the tire pressure information sensed to a central control module via the at least one self-powered low-energy wireless node.

13. The method according to claim 12, wherein the vehicle tire pressure monitoring system is waked up by a trigger condition, in particular by a vehicle motion and/or an ignition start.

14. The method according to claim 12 or 13, wherein the at least one tire pressure monitoring sensor and the at least one self-powered low-energy wireless node are synchronized prior to the transmitting step by operating the self-powered low-energy wireless node and/or the tire pressure monitoring sensor in a learning and synchronization mode, in particular wherein the tire pressure monitoring sensor and the self-powered low-energy wireless node synchronize with each other when both are operated in their respective learning and synchronization mode, further particularly both are operated in their respective normal operation mode after completion of the synchronization.

15. The method according to any of claims 12 to 14, wherein the self-powered low-energy wireless node is powered on/off at predicted times which are obtained in the respective learning and synchronization mode and/or wherein the self- powered low-energy wireless node is powered on/off at defined times submitted by the tire pressure monitoring sensor.