JP7645151B2 - Wireless transmission device and transmission system - Google Patents

Description

The present invention relates to a data transmission unit that transmits video data, and in particular to a data transmission unit, wireless transmission device, and transmission system that can notify a video data receiving device in advance of the suspension or resumption of video reception, improving convenience and enabling stable operation.

[Prior art description: FIG. 6]
A typical video transmission system will be described with reference to Fig. 6. Fig. 6 is an explanatory diagram showing a schematic configuration of a conventional video transmission system.
As shown in FIG. 6, the video transmission system includes a conventional video shooting and transmission device 10', a private wireless communication network 40, a wireless network 30, and a video data storage and display device 20, and transmits video data shot by the video shooting and transmission device 10' to the video data storage and display device 20.

The video shooting and transmission device 10' shoots video and transmits the video data by wireless communication.
The private wireless communication network 40 is a wireless communication network of 5G (fifth generation mobile communication system). Since the resolution of the video shooting unit 101 is improved to HD (High Definition) and 4K, and a bandwidth of about 15 Mbps for upload and about 7 Mbps for download is required, the private wireless communication network 30 uses local 5G, which has a larger transmission bandwidth than LTE (upstream 250 Mbps, downstream 500 Mbps).

The wireless network 30 includes a wireless transmitting/receiving section and a packet processing section, and performs wireless communication with the video shooting and transmitting device 1', and also performs communication with the video data storage and display device 20 via a cable.
The video data storage and display device 20 receives and stores the transmitted video data, and also displays it on the display unit.

[Configuration of a conventional video recording and transmission device: Fig. 7]
The configuration of a conventional video shooting and transmission device 10' will be described with reference to Fig. 7. Fig. 7 is an explanatory diagram showing the configuration of a conventional video shooting and transmission device 10'.
As shown in FIG. 7, a conventional video shooting and transmission device 10' is composed of a higher-level device 10'a and a lower-level device 10'b.
The higher-level device 10 ′ a includes a video shooting section 101 , a power supply section 102 , an operation section 103 , and a control section 104 , and each section of the higher-level device 10 ′ a is connected to each other via an internal bus 100 .
The higher-level device 10'a also includes a higher-level configuration (higher-level machine) of a data transmission section 107, which will be described later.

The lower-level device 10'b comprises a temperature detection section 105, a wireless circuit section 106, an antenna 109, and a power generation section 110, and each section of the lower-level device 10'b (device side) is connected by an internal bus .
The lower-level device 10'b also includes the lower-level configuration (lower-level machine) of the data transmission unit 107.
The upper bus 100 and the lower bus 108 are connected by a data transmission unit 107 .

The configuration of the higher-level device 10'a will now be described.
The video shooting unit 101 is, for example, a surveillance camera, which shoots video, converts it into an electrical signal, and sends the video data to the data transmission unit 107 .
The power supply unit 102 receives AC 100V power from the outside, and supplies the power required for the video shooting and transmission device 10 ′ via the internal bus 100 .

The operation unit 103 sets the resolution of the video capture unit, etc. The resolution can be, for example, HD or 4K.
The control unit 104 adjusts the shooting direction, focus, and light amount of the video shooting unit 101, processes the video data converted into an electrical signal, such as correcting the contours of the video data, and recognizes the subject.

The lower level device 10 ′ b constitutes a radio device, and the radio circuit section 106 receives the video data transmitted from the higher level device 10 ′ a via the data transmission section 107 and transmits it to the private radio 40 via the antenna 109 .
It also down-converts a high-frequency signal received by the antenna 109 and outputs it to the higher-level device 10 ′ a via the data transmission section 107 .

The power generation unit 110 receives power from the power supply unit 102 via the data transmission unit 10, and generates power to be supplied to the temperature detection unit 105 and wireless circuit unit 106 on the device side.
The temperature detection unit 105 detects the temperature of the wireless circuit unit 106, and if the temperature exceeds the standard, it notifies the data transmission unit 107 of this and outputs an instruction to the power generation unit 110 to stop supplying power to the wireless circuit unit 106.
In other words, radio circuit section 106 stops transmitting and receiving operations when the temperature exceeds a reference value.

[Configuration of a conventional data transmission unit: Figure 8]
Next, the configuration of the conventional data transmission unit 107 used in the conventional video shooting and transmission device of Fig. 7 will be described with reference to Fig. 8. Fig. 8 is an explanatory diagram showing the configuration of the conventional data transmission unit 108.
As shown in FIG. 8, the conventional data transmission unit 107 uses a USB cable 206 that complies with USB 2.0 or USB 3.0.
In the USB 2.0 or USB 3.0 interface, the side that realizes the parent functions of power supply and data communication is the host 200, and the side that realizes the child functions is the device 201.

The host 200 includes a USB data transmission/reception unit 202 and is connected to the bus 100 shown in FIG.
The device 201 includes a USB data transmission/reception unit 203 and is connected to the bus 108 .
The data transmission/reception units 202 and 203 transmit and receive data via a USB cable 206 .

Here, the USB cable 26 is regulated to be able to supply 2.5W of power with a rated voltage of 5V and a maximum current of 500mA in the case of USB2.0, and 4.5W with a rated voltage of 5V and a maximum current of 900mA in the case of USB3.0.
When local 5G is used as the private wireless system, the power in the wireless circuit unit 106 becomes larger than when LTE (Long Term Evolution) is used, and the peak power becomes 15 W.
Therefore, in addition to the USB cable 206 for data transmission, at least two power supply lines 204 are required: a power line and a GND line.

Furthermore, when the temperature detection section 105 detects a temperature rise in the wireless circuit section 106 and notifies the host side, at least a signal line and GND are required as the contact signal line 205 in addition to the USB cable 206 .
That is, the conventional data transmission unit 107 requires the power supply line 204 and the contact signal line 205 in addition to the USB cable 206 for data transmission, and thus requires three types of cables and connectors.

Furthermore, in order to prevent the device from becoming larger in size, if the temperature detection unit 105 detects an increase in temperature in the wireless circuit unit 106 but does not notify the host side, the contact signal line becomes unnecessary. However, if the operation of the wireless circuit unit 106 stops without warning, the image on the receiving side's video data storage and display device 20 will suddenly stop, and the receiving side will not know the cause and will have difficulty dealing with the situation.

[Related Technology]
Incidentally, a conventional technique relating to the transmission of video data is disclosed in Japanese Patent Laid-Open Publication No. 2009-100246 entitled "Display Device" (Patent Document 1).
Japanese Patent Laid-Open No. 2003-233693 describes a technique for acquiring video information from an external device, such as a mobile phone, connected to a display device by transmitting a video acquisition request at predetermined periodic intervals to the external device.

JP 2009-100246 A

As mentioned above, conventional data transmission units use USB 2.0 or USB 3.0, which requires power supply lines and contact signal lines in addition to the data transmission cable, resulting in increased device costs and larger circuit boards.

In addition, in conventional video capture and transmission devices, if the temperature detection unit 105 detects a temperature rise in the wireless circuit unit 106 but does not notify the host side, the operation of the wireless circuit unit 106 will stop without warning, causing the video on the receiving side's video data storage and display device to suddenly stop, and since the cause of this is unknown, it is difficult to respond.

Patent document 1 does not describe a data transmission section that includes a host machine, a subordinate machine, and a single cable that connects the host machine and the subordinate machine, and that transmits control information related to the power required by the subordinate device to the host machine and notifies the subordinate device of fluctuations that occur in the subordinate device.

The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a data transmission unit, wireless transmission device, and transmission system that can improve convenience by notifying a control unit and a destination video data storage and display device in advance of the suspension or resumption of data transmission from the wireless circuit unit, while preventing increases in device costs and increases in the size of the board.

The present invention, which solves the problems of the above-mentioned conventional examples, transmits specific data and comprises a host machine, a subordinate machine, and only one cable connecting the two, the host machine transmits specific data input from the host machine to the subordinate machine, the subordinate machine has a data transmission unit which transmits control information related to power to the host machine and notifies the subordinate machine of fluctuations occurring on the side of the subordinate machine, the host device including the host machine has a control unit which controls the transmission of the specific data, the subordinate device including the subordinate machine has a wireless circuit unit which wirelessly transmits the specific data and a temperature detection unit which detects the temperature of the subordinate device, the temperature detection unit outputs an instruction to stop the supply of power to the wireless circuit unit depending on the temperature situation, and the subordinate machine monitors the temperature information from the temperature detection unit and notifies the control unit of the host device that the supply of power to the wireless circuit unit is stopped .

The present invention is also characterized in that in the wireless transmission device, the control unit of the higher-level device receives a notification from the lower-level device that the power supply to the wireless circuit unit has been stopped, and notifies the destination of the specific data of the stoppage.

The present invention is also characterized in that in the wireless transmission device, the specific data is image data, and the control unit of the higher-level device stores the image data in a connected memory unit while the power supply to the wireless circuit unit is stopped, and transmits the stored image data after the power supply to the wireless circuit unit is resumed.

The present invention also provides a transmission system that includes any of the wireless transmission devices described above and an image processing device as a destination of the wirelessly transmitted data, and the wireless circuit unit wirelessly transmits specific data using 5G.

According to the present invention, a wireless transmission device transmits specific data and comprises a host machine, a subordinate machine, and only one cable connecting the two, the host machine transmits specific data input from the host machine to the subordinate machine, and the subordinate machine is provided with a data transmission unit that transmits control information related to power to the host machine and notifies the host machine of fluctuations occurring on the subordinate machine side, the host device including the host machine is provided with a control unit that controls the transmission of the specific data, and the subordinate device including the subordinate machine is provided with a wireless circuit unit that wirelessly transmits the specific data and a temperature detection unit that detects the temperature of the subordinate device, the temperature detection unit outputs an instruction to stop the supply of power to the wireless circuit unit depending on the temperature situation, and the subordinate machine monitors the temperature information from the temperature detection unit and notifies the control unit of the host device that the supply of power to the wireless circuit unit is stopped.Therefore, without increasing the cost of the device, the control unit of the host device can grasp the operating state of the subordinate device based on the state of power required by the subordinate device, and it is possible to recognize in advance that the operation of a component that consumes a lot of power, such as the wireless circuit unit, will be stopped or resumed.

In addition, according to the present invention, the control unit of the upper device is the wireless transmission device that receives a notification from the lower device that the power supply to the wireless circuit unit has been stopped and notifies the destination of the specific data of the stop, so that the destination can recognize in advance that the transmission of the specific data will be stopped, which has the effect of improving the convenience of system operation.

In addition, according to the present invention, the specific data is image data, and the control unit of the higher-level device stores the image data in the connected storage unit while the power supply to the wireless circuit unit is stopped, and the wireless transmission device transmits the stored image data after the power supply to the wireless circuit unit is resumed. This has the effect of ensuring that image data during the period when the transmission operation of the wireless circuit unit is stopped can be transmitted to the destination.

1 is a configuration block diagram of a video shooting and transmission device according to an embodiment of the present invention (the present video shooting and transmission device). FIG. 2 is an explanatory diagram showing the configuration of the data transmission unit. FIG. 2 is an explanatory diagram showing the configuration of a USB PD control unit. 4 is an explanatory diagram showing messages transmitted and received between a DFP/source 400 and a UFP/sink 401. FIG. FIG. 11 is an explanatory diagram showing a sequence in the data transmission unit 307. FIG. 1 is an explanatory diagram showing a schematic configuration of a video transmission system. FIG. 1 is an explanatory diagram showing the configuration of a conventional video shooting and transmission device 10'. FIG. 1 is an explanatory diagram showing a configuration of a conventional data transmission unit 108.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings.
[Outline of the embodiment]
The data transmission unit of an embodiment of the present invention (this data transmission unit) comprises a host unit, a subordinate unit, and a single cable connecting the host unit and the subordinate unit, and the host unit transmits specific data such as video data input from the host device to the subordinate unit, and the subordinate unit transmits control information regarding the power required by the subordinate unit to the host device to notify it of fluctuations occurring in the subordinate device.Therefore, without using multiple types of cables, the host device can grasp the operating status of the subordinate device based on the power required by the subordinate device, and can recognize in advance that operation of a component that consumes a lot of power, such as a radio circuit unit, will stop or resume.

The wireless transmission device according to the embodiment of the present invention (the wireless transmission device) includes the data transmission unit, and includes a wireless circuit unit that wirelessly transmits data to the lower-level device including the lower-level device, and a temperature detection unit that detects the temperature of the wireless circuit unit. The temperature detection unit outputs an instruction to stop the power supply to the wireless circuit unit depending on the temperature situation, and the lower-level device monitors the temperature information from the temperature detection unit and notifies the control unit of the upper-level device including the upper-level device that the power supply to the wireless circuit unit is stopped, and the control unit notifies the destination of the data transmission of the stop. This prevents increases in device costs and increases in the size of the board, and allows the control unit to recognize that the wireless circuit unit has stopped or resumed operation and notify the destination of the data transmission. Since the destination can recognize the stop or resume of data in advance, no special measures are required, improving convenience and enabling stable operation.

The transmission system according to the embodiment of the present invention (the present transmission system) is a transmission system equipped with the present wireless transmission device.

[Configuration of a video shooting and transmission device according to an embodiment: FIG. 1]
FIG. 1 is a block diagram showing the configuration of a video shooting and transmission device according to an embodiment of the present invention (the video shooting and transmission device).
This video recording and transmission device is used in the transmission system shown in FIG. 6, and corresponds to the wireless transmission device recited in the claims.
The video recording and transmission device transmits video data as the specific data described in the claims. In this embodiment, the video recording and transmission device is described as an example of a wireless transmission device, but it may be a device that transmits other data, not limited to video data.

As shown in FIG. 1, the basic configuration of the video shooting and transmission device 10 is the same as that of the conventional video shooting and transmission device 10' shown in FIG. 7, and includes a higher-level device 10a and a lower-level device 10b.
The parts similar to those of the conventional video capture and transmission device 10' include a video capture unit 301, a power supply unit 302, an operation unit 303, and a bus 300 of the higher-level device 10a, and a temperature detection unit 305, a wireless circuit unit 306, a power generation unit 310, and a bus 308 of the lower-level device 10b, while the characteristic parts of this video capture and transmission device 10 include a control unit 304, a memory unit 311, and a data transmission unit 307 of the higher-level device 10a.
As will be described later, a higher-level device, which is a configuration on the higher side of the data transmission section 307, is included in a higher-level device 10a, and a lower-level device, which is a configuration on the lower side, is included in a lower-level device 10b.
Detailed description of the parts similar to those of the conventional video shooting and transmission device 10' will be omitted.

The control unit 304 operates partially differently from the control unit 104 provided in the conventional video shooting and transmission device 10'.
Moreover, the data transmission unit 307 is different in configuration and operation from the conventional data transmission unit 307 .
As described below, the storage unit 311 accumulates video data captured while the wireless circuit unit 306 is stopped.

[Configuration of this data transmission unit: Figure 2]
The configuration of the data transmission unit 307, which is a characteristic part of the video shooting and transmission device 10, will be described with reference to Fig. 2. Fig. 2 is an explanatory diagram showing the configuration of the data transmission unit.
First, a feature of the data transmission unit 307 is that a USB Type-C cable conforming to USB PD (USB Power Delivery) is used as the USB cable 406. The USB cable 406 is capable of transmitting video data, supplying power, contact signals, and various messages through a single cable.

Conventionally, three types of cables and connectors were required to transmit video data, power, and contact signals, but with this data transmission unit 307, transmission can be achieved using one type of cable, reducing the cost and size of the device.

As shown in FIG. 2, the data transmission unit 307 includes a downstream facing port (DFP) on the upstream side connected by a USB cable 406, which serves as the host for data transmission, and an upstream facing port (UFP) on the downstream side, which serves as the slave for data transmission. It also includes a source for supplying power on the upstream side, and a sink for receiving power on the downstream side.

The upper-level DFT and source are integrally provided to constitute a DFP/source (upper-level machine) 400. The DFP/source 400 corresponds to the upper-level machine recited in the claims.
The lower-level UFP and sink are also integrally provided to constitute a UFP/sink (lower-level machine) 401. The UFP/sink 401 corresponds to the lower-level machine recited in the claims.
1. Moreover, the DFP/source 400 is connected to the bus 300 shown in FIG.

The DFP/source 400 includes a USB PD control unit 402 and a USB data transceiver unit 403, and similarly, the UFP/sink 401 includes a USB PD control unit 404 and a USB data transceiver unit 405.

The USB PD control unit 402 and the USB PD control unit 404 transmit and receive messages related to power. The messages related to power will be described later.
For example, the USB PD control unit 404 of the UFP/sink 401 notifies the USB PD control unit 402 of the DFP/source 400 of the voltage and current required by the lower device 10 b connected to the UFP/sink 401 based on temperature information from the temperature detection unit 305.

In addition to transmitting and receiving video data, the USB data transmission/reception unit 403 and the USB data transmission/reception unit 405 are characterized in that the data transmission unit 307 transmits data notifying that the transmission operation of the wireless circuit unit 306 will stop and data notifying that the transmission operation will resume from the control unit 304 of the higher-level device 10a to the video data storage and display device 20, which is the destination of the video data.

[Configuration of USB PD control unit: Figure 3]
The configuration of the USB PD control units 402 and 404 will be described with reference to Fig. 3. Fig. 3 is an explanatory diagram showing the configuration of the USB PD control units.
As shown in FIG. 3 , the USB PD control units 402 and 404 include a CPU (Central Processing Unit) 501, a volatile memory 502, a non-volatile memory 503, a power monitoring unit 504, a general-purpose input/output terminal 505, an ADC (Analog Digital Converter) 506, and a PD communication PHY 507.

The CPU 501 starts a program stored in the non-volatile memory 503 and controls the entire USB PD control unit 402 .
The non-volatile memory 503 stores the programs executed by the CPU 501 .
The volatile memory 501 operates as a main memory, expands programs, and holds data.

The USB PD control unit 402 and the USB PD control unit 404 have the same configuration, but perform different operations because the programs stored in the non-volatile memory 503 are different, or, among the stored programs, the programs that are activated according to the settings are different.
That is, the USB PD control unit 402 realizes the function of DFP/source, and the USB PD control unit 404 realizes the function of UFP/sink.

The power monitoring unit 504 operates differently in the DFP/source 400 and the UFP/sink 401, and in the USB PD control unit 402 of the DFP/source 400, the power monitoring unit 504 monitors whether the power from the power supply unit 302 shown in FIG. 1 is in an overvoltage or overcurrent state.
Furthermore, in the USB PD control unit 404 of the UFP/sink 401, a power monitoring unit 504 monitors the power supplied to the power generating unit 310 in FIG. 1 for overvoltage and overcurrent.

A general-purpose input/output terminal 505 performs input/output to the outside, and outputs a change in the state of a signal at an external terminal to the CPU 301 via the internal bus 500 .
The ADC 506 converts analog signals, such as external temperature changes, into digital data.
The CPU 501 can detect signals and temperature information from external terminals via the bus 500 .
The PD communication PHY 507 is connected to the signal lines CC1 and CC2 of the USB cable 406 , and transmits signals between the USB PD control unit 402 and the USB PD control unit 404 .

[Outline of operation of the data transmission unit and the video recording and transmission device: Figures 1 to 3]
Here, the operation of the data transmission unit 307 and the video shooting and transmission device 10 will be described with reference to FIGS.
In this video shooting and transmission device 10, similarly to the conventional video shooting and transmission device 10', the temperature detection unit 305 detects the temperature of the wireless circuit unit 306 and outputs the temperature information to the data transmission unit 307, and if the detected temperature information is higher than a reference value, outputs an instruction to the power generation unit 310 to stop supplying power to the wireless circuit unit 306.

In the data transmission unit 307 of the video shooting and transmission device 10, the USB PD control unit 404 of the UFP/sink 401 monitors temperature information from the temperature detection unit 305, and if the temperature is higher than a set value, notifies the USB PD control unit 402 of the DFP/source 400 that the power required by the lower device 10b will be significantly reduced. This notification is sent before the wireless circuit unit 306 actually stops.
In the data transmission unit 307, the information relating to this power is exchanged using a specific message as described below.

When the USB PD control unit 402 of the DFP/source 400 receives a notification that the power required by the lower device 10b is decreasing, it outputs the notification to the control unit 304 of the upper device 10a, and the control unit 304 determines that the wireless circuit unit 306 is shutting down, and notifies the video data storage and display device 20, which is the destination of the video data, that the transmission of the video data will stop.

As a result, the video data storage and display device 20 recognizes that the video data will stop before the wireless circuit unit 306 stops transmitting due to a rise in temperature, and displays this information on the display screen, for example, allowing the operator to respond calmly.

[Messages between DFP/Source 400 and UFP/Sink 401: FIG. 4]
Next, messages relating to power information exchanged between the DFP/source 400 and the UFP/sink 401 of the data transmission unit 307 will be described with reference to Fig. 4. Fig. 4 is an explanatory diagram showing messages transmitted and received between the DFP/source 400 and the UFP/sink 401.
As shown in FIG. 4, USB PD messages include control messages and data messages.
A control message is a message that does not require any control messages or data to manage the flow.
A data message is a message used to transfer data such as power supply information.

Source_Capabilities is a data message from a source to a sink that indicates the type of voltage and current the source can supply.
A Request is a data message from the sink to the source that specifies the voltage and current required by the sink from the Source_Capabilities sent immediately before.

Sink_Capabilities is a data message from the sink to the source, notifying the sink of the voltage and current required. For example, when the wireless circuit unit 308 is operating normally, the maximum settable values for voltage and current are notified. On the other hand, when the wireless circuit unit 308 becomes too hot and is about to stop operating, a value of "0" is notified for both the current and voltage.

Accept is a control message transmitted in both directions, from source to sink and from sink to source, to indicate acceptance of a data message.
Reject is a control message transmitted in both directions, from source to sink and from sink to source, to indicate that a data message is not accepted.
PS_RDY is a control message from source to sink that indicates that the VBUS has been powered on or off.

[Sequence in the data transmission section: Figure 5]
Next, the sequence in data transmission section 307 according to the temperature state of radio circuit section 306 will be described with reference to Fig. 5. Fig. 5 is an explanatory diagram showing the sequence in data transmission section 307.
Note that while Figure 5 mainly shows the exchange between the USB PD control unit 402 of the DFP/source 400 and the USB PD control unit 404 of the UFP/sink 401, other transmission information is also described in order to make the operation of this video shooting and transmission device easier to understand.

When the USB PD control unit 402 of the DFP/source 400 (hereinafter simply referred to as the DFP/source 400) receives a USB attach notification by connecting the USB cable 406 (S1), it transmits to the USB PD control unit 404 of the UFP/sink 401 (hereinafter simply referred to as the UFP/sink 401) the amount of power (type of voltage and current) that can be supplied from the higher-level device 10a by a Source Capabilities message (S2).

The UFP/sink 401 receives the Source_Capabilities message and transmits the amount of power (type of voltage and current) required by the lower device 10b from the Source_Capabilities message to the DFP/source 400 in a Request message (S3).
Under normal circumstances (when the temperature of the wireless circuit section 306 is normal), information indicating "maximum voltage, maximum current" is transmitted by a Request message.

When the DFP/source 400 receives the Request, it sends an Accept message indicating that it can accept the request (S4), then sends a PS_RDY message (S5), and starts supplying power to the power generation unit 310 via the UFP/sink 401 (S6).

On the other hand, the temperature detection section 305 detects the temperature of the wireless circuit section 306 and outputs the temperature information to the UFP/sink 401 .
Then, when the UFP/sink 401 compares the temperature from the temperature detection unit 305 with a preset threshold value and determines that the temperature of the wireless circuit unit 306 has increased (S10), the UFP/sink 401 sends a Sink_Capabilities message to the DFP/source 400 to notify it that there has been a change in the amount of power required (S11).

Specifically, since the amount of power required will be extremely small due to the wireless circuit unit 306 being shut down, the UFP/sink 401 transmits a Sink_Capabilities message indicating "Voltage 0, Current 0". In other words, this message indicates that the wireless circuit unit 306 will soon be shut down.

In addition, since the UFP/sink 401 needs to notify the DFP/source 400 that the wireless circuit unit 306 will soon stop before the temperature detection unit 305 issues an instruction to the power generation unit 310 to stop the power supply to the wireless circuit unit 306, the threshold value of the temperature information in the UFP/sink 401 is set to a temperature lower than the standard for the instruction to stop the power supply in the temperature detection unit 305.

In addition, if the temperature information momentarily exceeds the threshold due to a sudden error or the like, a message is not sent immediately; instead, a message is sent only if the state where the threshold is exceeded continues for a certain period of time.

When the DFP/source 400 receives a Sink_Capabilities message indicating "Voltage 0, Current 0", it transmits an Accept message (S12) and outputs specific information indicating that the wireless circuit unit 306 is to be stopped to the control unit 304 of the higher-level device 10a shown in FIG. 1.

When the control unit 304 receives the information indicating that the wireless circuit unit 306 has been stopped, it transmits information (a video transmission stop message) notifying the video data storage and display device 20 in advance that the wireless circuit unit 304 will be stopped (S13).
The video transmission stop message is transmitted in a different system from the power control message.
Then, in response to an instruction from the temperature detection section 305, the power generation section 310 stops the power supply to the wireless circuit section 306, and the wireless circuit section 306 stops operating (S14).

The temperature detection unit 305 continues to detect the temperature even after the wireless circuit unit 306 stops operating, and the UFP/sink 401 compares the temperature information with a threshold value to detect the temperature of the wireless circuit unit 306 and outputs the temperature information to the DFP/source 400.
When the temperature of the radio circuit section 306 falls to a reference value or lower, the temperature detection section 305 outputs an instruction to the power generation section 310 to start supplying power to the radio circuit section 306 .

The UFP/sink 401 monitors the temperature information from the temperature detection unit 305, and when it determines that the temperature information has fallen below the threshold and the temperature of the wireless circuit unit has returned to normal (S20), the UFP/sink 401 notifies the DFP/source 400 that the amount of power required has changed by using a Sink_Capabilities message (S21).

Specifically, because the wireless circuit unit 306 resumes operation and power consumption increases, the UFP/sink 401 transmits a Sink_Capabilities message indicating "maximum voltage, maximum current." In other words, this message indicates that the wireless circuit unit 306 will soon resume transmission and reception operations.

Then, when the DFP/source 400 receives a Sink_Capabilities message indicating "maximum voltage, maximum current", it sends an Accept message (S22) and outputs specific information indicating that the wireless circuit unit 306 will resume operation to the control unit 304 of the higher-level device 10a.

When the control unit 304 receives information indicating that the wireless circuit unit 306 will resume operation, it transmits information (video transmission resumption message) to the video data storage device 20 to notify in advance that the wireless circuit unit 306 will resume operation (S23).
In this manner, the data transmission section and the video shooting and transmission device operate.

In addition, the video data captured while the wireless circuit unit 306 is stopped operating may be stored in the memory unit 311, and transmitted after the temperature of the wireless circuit unit 306 returns to normal, the power supply is resumed, and operation is resumed.
When storing in the storage unit 311, the amount of data may be reduced by appropriately thinning out the video data before storing, or by lowering the resolution before storing.

[Effects of the embodiment]
This data transmission unit comprises a DFP/source 400 as a higher-level device, a UFP/sink 401 as a lower-level device, and a single USB cable 406 compliant with USB PD that connects the two, and the DFP/source 400 transmits specific data such as video data input from the higher-level device 10a to the UFP/sink 401, and the UFP/sink 401 serves as a data transmission unit that transmits control information related to the power required by the lower-level device 10b to the higher-level device 10a and notifies the higher-level device 10a of fluctuations that occur in the lower device 10b. This has the effect of allowing the higher-level device 10a to grasp the operating state of the lower device 10b based on the state of the power required by the lower device 10b without increasing device costs, and being able to recognize in advance that operation of a component that consumes a lot of power, such as the wireless circuit unit 306, will stop or resume.

In addition, according to the video shooting and transmission device, the lower device 10b, which is equipped with the above-mentioned data transmission unit and is connected to the lower device UFP/sink 401, is equipped with a wireless circuit unit 306 that wirelessly transmits data and a temperature detection unit 305 that detects the temperature of the wireless circuit unit, and the temperature detection unit 305 outputs an instruction to stop the power supply to the wireless circuit unit 306 depending on the temperature situation, and the UFP/sink 401 monitors the temperature information from the temperature detection unit 305 and notifies the upper device 10a, which is connected to the upper device DFP/source 400, that the power supply to the wireless circuit unit 306 is stopped. The video capture and transmission device notifies the control unit 304, which then notifies the video data storage and display device 20, which is the data transmission destination, of the stoppage. This allows the control unit 304 to recognize the stoppage or restart of the wireless circuit unit 306 and notify the video data storage and display device 20 before it is stopped or resumed, without increasing the cost of the device. The video data storage and display device 20 can recognize the stoppage or restart of data in advance and does not need to take any special measures, which improves the convenience of system operation and enables stable operation.

In the above example, a configuration was described in which the video data storage and display device 20 is notified of the stop of operation due to the detection of an abnormality caused by a temperature rise in the wireless circuit unit 306. However, by configuring the device to be able to detect other abnormal conditions (e.g., an abnormality in the power generation unit 310) below the UFP/sink 401 and configuring the program in the USB PD control unit 404 to send a message to the DFP/source 400 when the abnormal condition is detected, the abnormal condition can be easily notified to the upper control unit 304, and further notified to the video data storage and display device 20 in the same way as in the case of a temperature rise, thereby improving convenience.

The present invention is suitable for a data transmission unit, a wireless transmission device, and a transmission system that can notify a video data receiving device in advance of the suspension or resumption of video reception, improving convenience and enabling stable operation.

10, 10'...Video capture and transmission device, 10a, 10'a...Higher-level device, 10b, 10'b...Lower-level device, 20...Video data storage and display device, 30...Wireless network, 101, 301...Video capture unit, 102, 302...Power supply unit, 103, 303...Operation unit, 104, 304...Control unit, 105, 305...Temperature detection unit, 106, 306...Wireless circuit unit, 107, 307...Data transmission unit, 110, 310...Power generation unit, 200...Host, 201...Device, 311...Memory unit, 400...DFP/source, 401...UFP/sink, 402, 404...USB PD control unit, 202, 203, 403, 405...USB data transmission and reception unit, 204...power supply line, 205...contact signal line, 206, 406...USB cable, 300, 308, 500...bus, 501...CPU, 502...volatile memory, 503...non-volatile memory, 504...power monitoring unit, 505...general-purpose input/output terminal, 506...ADC, 507...PD communication PHY

Claims (4)

a data transmission section for transmitting specific data, comprising a host machine, a subordinate machine, and only one cable connecting the two, the host machine transmitting the specific data input from the host machine to the subordinate machine, and the subordinate machine transmitting control information related to power to the host machine and informing the subordinate machine of fluctuations occurring on the side of the subordinate machine ;
The host device includes a control unit for controlling transmission of specific data,
A lower-level device including the lower-level machine includes a wireless circuit unit for wirelessly transmitting the specific data and a temperature detection unit for detecting a temperature of the lower-level device,
the temperature detection unit outputs an instruction to stop power supply to the wireless circuit unit according to a temperature state;
The wireless transmission device is characterized in that the lower device monitors temperature information from the temperature detection unit and notifies the control unit of the higher device that power supply to the wireless circuit unit is stopped. 2. The wireless transmission device according to claim 1 , wherein the control unit of the higher-level device receives a notice from the lower-level device that power supply to the wireless circuit unit has been stopped, and notifies a destination of transmission of specific data of the stoppage. the specific data is image data,
A wireless transmission device as described in claim 1 or 2, characterized in that the control unit of the higher-level device stores image data in a connected memory unit while power supply to the wireless circuit unit is stopped, and transmits the stored image data after power supply to the wireless circuit unit is resumed. 4. A wireless communication system comprising: a wireless transmission device according to claim 1 ; and an image processing device as a destination of the wirelessly transmitted data;
A transmission system characterized in that the wireless circuit unit wirelessly transmits specific data using 5G.

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