WIFI Internet of Things communication device and intelligent terminal

Abstract

The embodiment of the invention provides a WI FI Internet of Things communication device and an intelligent terminal, and the device comprises a receiving and transmitting antenna which is used for obtaining an electromagnetic wave signal in a space; the WI FI core board is used for converting the electromagnetic wave signal into electric energy and storing the electric energy so as to supply power to the WI FI core board; wherein the transmitting and receiving antenna is a dual-frequency antenna, a first electromagnetic wave signal in a space is acquired by using a low-frequency band to supply power to the WI FI core board, and a second electromagnetic wave signal is transmitted and received by using a high-frequency band to perform signal transmission. According to the invention, the problem that the communication device needs an external power supply and the power supply is difficult to replace in the prior art is solved.

Description

Technical Field

[0001] Embodiments of the present invention relate to the field of communications, and more particularly, to a WIFI Internet of Things communication device and an intelligent terminal. Background Art

[0002] In recent years, with the rapid development of the Internet of Things field, the number of Internet of Things devices has shown an exponential growth trend. However, at present, the vast majority of Internet of Things devices need to be externally powered by batteries. Due to the limited battery capacity, the batteries need to be replaced regularly to ensure the normal operation of the devices. Especially in some special cases, when the devices are installed underground, in walls or in toxic and harmful areas, it is extremely difficult to replace the batteries, which will bring huge maintenance costs. Summary of the Invention

[0003] Embodiments of the present invention provide a WIFI Internet of Things communication device and an intelligent terminal to at least solve the problem in the related art that the communication device needs an external power supply and the power supply replacement is difficult.

[0004] According to an embodiment of the present invention, a WIFI Internet of Things communication device is provided, including:

[0005] A transceiver antenna for acquiring electromagnetic wave signals in space;

[0006] A WIFI core board for converting the electromagnetic wave signals into electric energy and storing the electric energy to supply power to the WIFI core board;

[0007] Wherein, the transceiver antenna is a dual-band antenna, which uses the low-frequency band to acquire the first electromagnetic wave signal in space to supply power to the WIFI core board, and uses the high-frequency band to receive and transmit the second electromagnetic wave signal for signal transmission.

[0008] According to another embodiment of the present invention, an intelligent terminal is further provided, including the above device.

[0009] Through the present invention, due to the WIFI core board and transceiver antenna technology, the WIFI Internet of Things communication device can make full use of the electromagnetic wave signals in the environment for autonomous charging, and no longer completely rely on external batteries, thus solving the problem in the related art that the communication device needs an external power supply and the battery replacement is difficult, and achieving the effect of convenient charging. Brief Description of the Drawings

[0010] Figure 1 is an application scenario diagram of the device according to an embodiment of the present invention;

[0011] Figure 2 is a schematic structural diagram of a WIFI Internet of Things communication device according to an embodiment of the present invention;

[0012] Figure 3Schematic diagram of a radio frequency energy harvesting module, a power management module, and a WIFI scatter communication module according to an embodiment of the present invention;

[0013] Figure 4 Flowchart of software configuration for implementing an embodiment of the present invention. Detailed implementation manners

[0014] In the following, embodiments of the present invention will be described in detail with reference to the accompanying drawings and in conjunction with the embodiments.

[0015] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily need to be used to describe a specific order or sequence.

[0016] Figure 1 Application scenario diagram of the device according to an embodiment of the present invention, as Figure 1 shown, the device receives the electromagnetic wave signal sent by the base station and uses the electromagnetic wave signal for autonomous charging. The device can also detect the environmental information around the device (such as physical parameters such as temperature and humidity). When the device is bound to cultural relics, precious exhibits, etc., it can detect the abnormal movements of cultural relics, precious exhibits, etc., and obtain abnormal movement data. Then, after processing the environmental information and abnormal movement data, it is sent to the WIFI receiving device to remind the user holding the WIFI receiving device. Or when the device is placed around underground, inside the wall, a radiation source, a toxic and harmful area, the device can perform autonomous power supply, thus solving the problem of difficult battery replacement.

[0017] In one implementation manner, the device modulates the single-frequency electromagnetic wave emitted from the base station into a WIFI signal conforming to the IEEE 802.11 standard protocol by means of scattering, and is received by the WIFI receiving device for demodulation and decoding. Among them, the WIFI receiving device can be a wireless device such as a smart phone, a tablet computer, a router, a UFI (Universal Flash Storage), a CPE (Customer Premises Equipment), etc.

[0018] In an embodiment of the present invention, a WIFI Internet of Things communication device is provided, Figure 2 Schematic diagram of the WIFI Internet of Things communication device according to an embodiment of the present invention, as Figure 2 shown, the device includes:

[0019] A transceiver antenna for acquiring the electromagnetic wave signal in space;

[0020] A WIFI core board for converting the electromagnetic wave signal into electrical energy and storing it to supply power to the WIFI core board;

[0021] In an exemplary embodiment, the WIFI core board can be powered by a battery or not. For example, when the WIFI core board is powered by a battery, the battery is used to supply power to the WIFI core board. When the battery power is insufficient, the electromagnetic wave signal is converted into electrical energy to supply power to the WIFI core board. When the WIFI core board is not powered by a battery, the electromagnetic wave signal is converted into electrical energy and stored by the WIFI core board, and the stored electrical energy is used to supply power to the WIFI core board.

[0022] Among them, the transceiver antenna is a dual-band antenna. The low-frequency band is used to obtain the first electromagnetic wave signal in space, convert it, and then supply power to the WIFI core board. The high-frequency band is used to receive and transmit the second electromagnetic wave signal for signal transmission.

[0023] In an exemplary embodiment, the transceiver antenna is a single-port dual-band antenna, that is: the 2.4 GHz band is used in the scattering communication mode, and the 433 MHz band is used in the energy harvesting mode to reduce signal attenuation and collect as much radio frequency energy as possible. Among them, the 2.4 GHz band and the 433 MHz band are only exemplary illustrations, and the selection of frequency band data can be set according to actual situations.

[0024] In one embodiment, the WIFI core board includes:

[0025] A power management module, which is used to receive the DC electrical energy converted by the radio frequency energy harvesting module of the WIFI core board, regulate and store the DC electrical energy, and supply power to the WIFI core board.

[0026] Figure 3 It is a schematic structural diagram of the radio frequency energy harvesting module, power management module, and WIFI scattering communication module according to an embodiment of the present invention. In one embodiment, as Figure 3 shown, the power management module includes:

[0027] An input energy storage device, which is used to store DC electrical energy;

[0028] A sampling and regulation module, which is used to regulate the power output by the input energy storage device and output a regulated voltage;

[0029] An output energy storage device, which is used to store the regulated voltage to output a regulated power to supply power to the WIFI core board.

[0030] In an exemplary embodiment, as Figure 3 shown, the input energy storage device can be a capacitor C1, which is used to store the electrical energy output by the radio frequency energy harvesting module.

[0031] In one embodiment, the sampling regulation module includes a sampling circuit and a boost charging chip. The sampling circuit includes a first resistor and a second resistor. Among them,

[0032] One end of the first resistor is connected to the input energy storage device and the voltage acquisition pin of the boost charging chip.

[0033] In an exemplary embodiment,

[0034] One end of the second resistor is connected to the other end of the first resistor and the voltage sampling pin of the boost charging chip, and the other end is grounded.

[0035] The voltage filtering pin of the boost charging chip is grounded through a capacitor.

[0036] The voltage output pin of the boost charging chip is connected to the output energy storage device.

[0037] In an exemplary embodiment, the input energy storage device is used to store the energy collected by the front-stage radio frequency energy harvesting module. Since the output current may be small when the output voltage of the front-stage radio frequency DC conversion circuit is the highest, it is not the maximum power output point. The input voltage of the BQ25504 chip can be adjusted through the sampling circuit to ensure that the front-stage circuit can output at the maximum power. The BQ25504 chip is mainly used to charge the output energy storage device. Since the front-stage energy harvesting is often unstable or changes with the environment, the output energy storage device can ensure a constant power supply when the device needs it. At the same time, the energy stored in it can also supply power to the device when the peak current is generated during the operation of the post-stage device, avoiding abnormal power-off of the device.

[0038] In an exemplary embodiment, for example, as Figure 2 and Figure 3 shown, the boost charging chip can be a BQ25504 chip. The positive electrode of capacitor C1 is connected to the output end of the radio frequency to DC conversion circuit of the radio frequency energy harvesting module, one end of the first resistor R1, and the Vin_DC pin of the BQ25504 chip. The negative electrode of capacitor C1 is connected to one end of the second resistor R2 and is grounded. The other end of the second resistor R2 is connected to one end of the first resistor R1 and the VDC_SAMP pin of the BQ25504 chip. The VREF_SAMP pin of the BQ25504 chip is grounded through capacitor C2. The output energy storage device can be capacitor C3. The VOUT pin of the BQ25504 chip is connected to the positive electrode of capacitor C3 and the input end of the WIFI scattering communication module, and the negative electrode of capacitor C3 is grounded.

[0039] Among them, the radio frequency energy harvesting module includes an impedance matching module and a radio frequency to DC conversion circuit. The impedance matching module and the radio frequency to DC conversion circuit can adopt known technologies disclosed in related technologies, and will not be elaborated in the embodiments of the present invention.

[0040] The BQ25504 chip can be used for intelligent integrated energy harvesting and power consumption management, and is suitable for ultra-low power applications. Its design starts with a DC-DC boost converter / charger that can start working with only microwatt power. It can harvest and manage power in the range of microwatts (μW) to milliwatts (mW) generated by various DC sources such as photovoltaic (solar) generators or thermoelectric generators. The BQ25504 chip takes the lead among similar devices in implementing an efficient boost converter / charger for products and systems with strict power supply and operation requirements (such as wireless sensor networks (WSNs)). The boost converter can be started with a VIN as low as 330 mV, and after startup, it can continue to harvest energy with a VIN as low as 80 mV.

[0041] The BQ25504 chip also implements a programmable maximum power point tracking sampling network to optimize power transfer to the device. The VIN_DC open-circuit voltage sampling is programmed through an external resistor and held by an external capacitor (CREF). For example, for a solar cell with a maximum power point of 80% of the open-circuit voltage, the resistor divider can be set to 80% of the VIN_DC voltage, and at this time, the network will control VIN_DC near the sampled reference voltage. Alternatively, an external reference voltage can also be provided by a microcontroller (MCU) to generate a more complex MPPT algorithm.

[0042] To prevent damage to the energy storage element, the device monitors the maximum and minimum voltages with reference to the user-programmed undervoltage (UV) and overvoltage (OV) levels. When the voltage in the energy storage battery or capacitor drops below the preset critical value, the BQ25504 chip will switch the battery normal status flag and send it to the connected microprocessor. This warning signal should trigger a decrease in the load current to prevent the system from entering the undervoltage state. The OV, UV, and battery normal thresholds are all programmed separately.

[0043] In one embodiment, the WIFI core board further includes a WIFI scattering communication module and a sensor module; wherein,

[0044] The sensor module is used to collect physical parameters in the space and output the measurement results;

[0045] The WIFI scattering communication module includes:

[0046] A microprocessor, which is used to receive the measurement results output by the sensor module and the second electromagnetic wave signal received and transmitted by the transceiver antenna, fuse the measurement results into the second electromagnetic wave signal to obtain a fused signal, and send the fused signal to the mobile terminal.

[0047] In an exemplary embodiment, the microprocessor can adopt the low-power MSP430FR5959. After the microprocessor completes the digital modulation of the information, it outputs from the port of the controller at a rate of 44 Mbps, which is used to drive the radio frequency switch device to change the matching state of the antenna of the WIFI device, so as to scatter the UDP packet to be sent according to the WIFI protocol standard, and achieve WIFI scatter communication. Since the energy that the radio frequency energy harvesting module can collect is limited, the WIFI scatter communication module modulates the existing electromagnetic wave signals in the space through the backscattering method, replacing the traditional method of actively transmitting electromagnetic wave signals, which can greatly reduce the communication power consumption to ensure that the entire device truly realizes the self-powered effect. Of course, the rate of 44 Mbps is only an exemplary illustration, and the specific data can be set according to the actual situation.

[0048] For example, the following method can be adopted:

[0049] The sensor module collects temperature data: The temperature sensor module is used to collect the temperature data in the environment. The sensor module converts the measured temperature into an electrical signal and outputs it to the WIFI scatter communication module.

[0050] The WIFI scatter communication module receives the data of the sensor module: The microprocessor in the WIFI scatter communication module is responsible for receiving the temperature data output by the sensor module. The microprocessor communicates with the sensor module through a serial port or other interfaces and receives the temperature data.

[0051] The transceiver antenna of the WIFI scatter communication module conducts communication: The transceiver antenna in the WIFI scatter communication module is used to receive and transmit the second electromagnetic wave signal for communicating with the mobile terminal. The transceiver antenna receives the signal from the mobile terminal and transmits the signal to the microprocessor for processing.

[0052] Integrate the measurement result into the second electromagnetic wave signal: The microprocessor integrates the received temperature data into the second electromagnetic wave signal. The specific method can be to add a specific data packet to the second electromagnetic wave signal and pack the temperature data into information in a specific format.

[0053] Send the fused signal to the mobile terminal: The microprocessor sends the fused signal to the mobile terminal. The signal is sent through the transceiver antenna, and the mobile terminal receives the second electromagnetic wave signal containing the temperature data.

[0054] In summary, the mobile terminal can receive the fused signal and extract the temperature data therein. In this process, the WIFI core board realizes the functions of sensor data acquisition, data fusion, and signal transmission.

[0055] In one embodiment, the sensor module includes:

[0056] A temperature and humidity sensor, which is used to collect the physical parameters of temperature and humidity in a space and output the measurement results.

[0057] In an exemplary embodiment, the following method can be adopted:

[0058] The temperature and humidity sensor collects data: The temperature and humidity sensor module is responsible for sensing the temperature and humidity in the environment and converting these physical parameters into corresponding electrical signals. The sensor measures the temperature and humidity of the environment through sensitive elements (such as thermistors, humidity sensors) or other technologies.

[0059] Output the measurement results: The temperature and humidity sensor module converts the measured temperature and humidity data into electrical signals and outputs them to the WIFI scattering communication module. This can be achieved through an analog voltage or a digital interface.

[0060] The microprocessor receives the sensor output signal: The microprocessor in the WIFI scattering communication module is responsible for receiving the electrical signals output by the temperature and humidity sensor module. The microprocessor has corresponding analog / digital conversion functions or digital interfaces to receive and parse the output signals of the sensor module.

[0061] Fuse the temperature and humidity data into the second electromagnetic wave signal: The microprocessor fuses the received temperature and humidity data into the second electromagnetic wave signal in the WIFI scattering communication module. For example, the temperature and humidity data can be encoded into data packets in a specific format and added to the second electromagnetic wave signal.

[0062] Send the fused signal to the mobile terminal: The fused signal is sent to the mobile terminal by the transceiver antenna of the WIFI scattering communication module. The mobile terminal receives the second electromagnetic wave signal containing the fused temperature and humidity data.

[0063] Through the above method, the mobile terminal can receive the fused signal and extract the temperature and humidity data from it. The temperature and humidity sensor works in coordination with other modules of the WIFI core board to achieve the function of collecting the physical parameters of temperature and humidity in a space and outputting the measurement results.

[0064] In one embodiment, the sensor module includes:

[0065] An acceleration sensor, which is used to collect the acceleration of the device. When the acceleration is greater than or equal to a preset threshold, an interrupt signal is triggered to wake up the microprocessor in the standby state.

[0066] In an exemplary embodiment, the following method can be adopted:

[0067] Acceleration of the acquisition device: The acceleration sensor module is responsible for sensing the acceleration of the acquisition device and converting these physical parameters into corresponding electrical signals. The acceleration sensor measures the acceleration of the device through sensitive elements (such as microelectromechanical systems) or other technologies.

[0068] Trigger an interrupt signal: When the acceleration value detected by the acceleration sensor is greater than or equal to a preset threshold, an interrupt signal is generated. This interrupt signal can wake up the microprocessor in the standby state and make it enter the working state.

[0069] Wake up the microprocessor: The acceleration sensor successfully wakes up the microprocessor in the standby state by triggering an interrupt signal. After receiving the interrupt signal, the microprocessor immediately enters the working state for subsequent processing.

[0070] Data processing and fusion: The awakened microprocessor is responsible for receiving the interrupt signal output by the acceleration sensor module and performing corresponding data processing. According to specific requirements, the microprocessor may fuse the acceleration data into the second electromagnetic wave signal in the WIFI scattering communication module to obtain a fused signal.

[0071] Send the fused signal to the mobile terminal: The fused signal is sent to the mobile terminal by the transceiver antenna of the WIFI scattering communication module. The mobile terminal receives the second electromagnetic wave signal containing the fused acceleration data.

[0072] In the above manner, the mobile terminal can receive the fused signal and extract the acceleration data from it. The acceleration sensor works in coordination with other modules of the WIFI core board to achieve the acceleration of the acquisition device. When the acceleration is greater than or equal to the preset threshold, an interrupt signal is triggered to wake up the microprocessor in the standby state.

[0073] For example, when the device is carried by a patient or an elderly person, when the patient or the elderly person suddenly falls, the acceleration collected by the acceleration sensor is greater than or equal to the preset threshold, then an interrupt signal is triggered to wake up the microprocessor in the standby state, so that the microprocessor sends a warning signal and sends the warning signal to the mobile terminal of the nurse or family member to remind the nurse or family member. Among them, the preset threshold can be set according to the actual situation.

[0074] In one embodiment, the WIFI scattering communication module further includes:

[0075] A timer for changing the working mode of the antenna from supplying power to the WIFI core board by obtaining the first electromagnetic wave signal in the low frequency band in the first preset time period to transmitting signals by using the high frequency band to receive and transmit the second electromagnetic wave signal after the first preset time period.

[0076] In an exemplary embodiment, the following method may be adopted:

[0077] In the initial state, the entire device is in the standby state. In this state, the WIFI core board obtains energy from the first electromagnetic wave signal in the low frequency band through the transceiver antenna for power supply.

[0078] After the first preset time period, the timer is triggered, and the working mode of the antenna is changed from using the low frequency band for power supply to using the high frequency band for signal transmission.

[0079] At this time, signal transmission is carried out through the electromagnetic wave signal in the high frequency band, and power supply is carried out using the energy storage of the WIFI core board.

[0080] For example, assume that the device is used for exhibit monitoring, and the sensor module includes a temperature and humidity sensor and an acceleration sensor. The device is connected to the exhibit. When an event such as the exhibit falling off the display stand occurs, the acceleration sensor detects that the acceleration of the exhibit exceeds the preset threshold. At this time, the microprocessor is awakened, receives the temperature and humidity data collected by the temperature and humidity sensor, and integrates these data into the second electromagnetic wave signal. After the first preset time period, the timer is triggered, and the working mode of the antenna is changed from the low frequency band to the high frequency band. In the changed working mode, the device transmits the signal integrated with the temperature and humidity data to the mobile terminal by sending the electromagnetic wave signal in the high frequency band, thus achieving the purpose of data transmission. After the data transmission is completed, the timer can re-time and repeat the above process when the next trigger condition is met.

[0081] In one embodiment, the timer is further configured to cause the microprocessor to switch from the working state to the standby state after a second preset time period.

[0082] In an exemplary embodiment, after the device finishes working triggered by an event, the microprocessor is caused to switch from the working state to the standby state after a second preset time period. At this time, the microprocessor enters the standby sleep state, thus effectively saving the power consumption of the microprocessor.

[0083] In an exemplary embodiment, in order to minimize power consumption, the WIFI communication device enters the low-power mode standby state immediately after system initialization and completion of basic settings. All functional functions are based on the interrupt service interface. One of the interrupt signals is triggered by the abnormal vibration of the acceleration sensor, and the other interrupt is triggered by the TPL5000 timer once every 10s.

[0084] Figure 4 It is a flowchart of the software configuration for implementing the embodiment of the present invention. In one embodiment, as Figure 4 shown, the process of software configuration is as follows:

[0085] 1. System initialization;

[0086] 2. Temperature, humidity and acceleration sensor configuration;

[0087] 3. Set the timer trigger time interval;

[0088] 4. The microprocessor enters the standby mode;

[0089] 5. Determine whether an interrupt trigger signal is received. If so, determine whether the interrupt is triggered by acceleration data. If the interrupt trigger signal is not received, keep the microprocessor in the standby state;

[0090] 6. If it is determined that the interrupt is triggered by acceleration data, send a vibration alarm data packet to make the microprocessor work;

[0091] 7. If it is determined that the interrupt is not triggered by acceleration data, determine whether the energy is sufficient. If it is sufficient, enter the data acquisition, encoding and modulation process of the temperature and humidity sensor. If the energy is insufficient, keep the microprocessor in the standby state.

[0092] In an embodiment of the present invention, an intelligent terminal is further provided, including the above device.

[0093] It should be noted that the above-mentioned various modules can be implemented by software or hardware. For the latter, it can be implemented in the following ways, but not limited to this: the above modules are all located in the same processor; or, the above-mentioned various modules are respectively located in different processors in any combination form.

[0094] Obviously, those skilled in the art should understand that the above-mentioned modules or steps of the present invention can be implemented by a general-purpose computing device. They can be concentrated on a single computing device, or distributed on a network composed of multiple computing devices. They can be implemented by program codes executable by the computing device. Thus, they can be stored in a storage device and executed by the computing device. And in some cases, the steps shown or described can be executed in a different order from here, or they can be made into individual integrated circuit modules respectively, or multiple modules or steps among them can be made into a single integrated circuit module to implement. In this way, the present invention is not limited to any specific combination of hardware and software.

[0095] The above is only the preferred embodiment of the present invention and is not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A WIFI Internet of Things communication device, characterized in that, Comprising: A transceiver antenna for acquiring electromagnetic wave signals in space; A WIFI core board for converting the electromagnetic wave signals into electric energy and storing same to supply power to the WIFI core board; Wherein, the transceiver antenna is a dual-band antenna, and uses the low-frequency band to acquire a first electromagnetic wave signal in space to supply power to the WIFI core board, and uses the high-frequency band to receive and transmit a second electromagnetic wave signal for signal transmission.

2. The device according to claim 1, characterized in that, The WIFI core board includes: A power management module for receiving the DC electric energy converted by the radio frequency energy harvesting module of the WIFI core board, regulating and storing the DC electric energy to supply power to the WIFI core board.

3. The device according to claim 2, wherein The power management module includes: An input energy storage device for storing the DC electric energy; A sampling and regulation module for regulating the power output by the input energy storage device and outputting a regulated voltage; An output energy storage device for storing the regulated voltage to output a regulated power to supply power to the WIFI core board.

4. The device according to claim 3, characterized in that The sampling and regulation module includes a sampling circuit and a boost charging chip, and the sampling circuit includes a first resistor and a second resistor; wherein, One end of the first resistor is connected to the input energy storage device and the voltage acquisition pin of the boost charging chip; One end of the second resistor is connected to the other end of the first resistor and the voltage sampling pin of the boost charging chip, and the other end is grounded; The voltage filtering pin of the boost charging chip is grounded through a capacitor; The voltage output pin of the boost charging chip is connected to the output energy storage device.

5. The device according to claim 1, characterized in that, The WIFI core board further includes a WIFI scattering communication module and a sensor module; wherein, The sensor module is used for collecting physical parameters in space and outputting a measurement result; The WIFI scattering communication module includes: A microprocessor for receiving the measurement result output by the sensor module and the second electromagnetic wave signal received and transmitted by the transceiver antenna, fusing the measurement result into the second electromagnetic wave signal to obtain a fused signal, and sending the fused signal to a mobile terminal.

6. The device according to claim 5, wherein The sensor module includes: A temperature and humidity sensor for collecting physical parameters of temperature and humidity in space and outputting a measurement result.

7. The device according to claim 5, characterized in that, The sensor module includes: An acceleration sensor for collecting the acceleration of the device, and triggering an interrupt signal to wake up the microprocessor in the standby state when the acceleration is greater than or equal to a preset threshold.

8. The device according to claim 5, characterized in that, The WIFI scattering communication module further includes: A timer for changing the working mode of the antenna from using the low-frequency band to acquire a first electromagnetic wave signal in space to supply power to the WIFI core board to using the high-frequency band to receive and transmit a second electromagnetic wave signal for signal transmission after a first preset time period.

9. The device according to claim 8, wherein The timer is further used for changing the microprocessor from the working state to the standby state after a second preset time period.

10. An intelligent terminal, characterized in that, Including the device according to any one of claims 1 to 9 above.

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