Communication device, communication system, and communication method

Abstract

[Problem] To efficiently transmit bidirectional signals with low power consumption. [Solution] This communication device comprises: a communication unit that transmit signals with a communication partner device; and a communication control unit that changes a signal ratio in a first direction, which is to the communication partner device, and a signal ratio in a second direction, which is from the communication partner device, depending on the state of signal transmission with the communication partner device.

Description

Technical Field

[0001] The present disclosure relates to a communication device, a communication system, and a communication method.

Background Art

[0002] A technology for transmitting a large amount of data at high speed and bidirectionally using a single cable has been proposed. In conventional high-speed transmission technologies, the FDD (Frequency Division Duplexing) method is often used. When performing bidirectional signal transmission between a master device and a slave device using the FDD method, the downlink signal for transmitting a signal from the master device to the slave device and the uplink signal for transmitting a signal from the slave device to the master device use different frequency bands. In the FDD method, bidirectional signals can be transmitted at the same timing. Since signals with a larger transmission capacity require a wider frequency band, it is common to perform signal transmission using a wide frequency band on the high-frequency side, and signals with a small transmission capacity are transmitted using a narrow frequency band on the low-frequency side.

[0003] In the receiving units of the master device and the slave device respectively, it is necessary to completely separate the signals in the uplink and downlink directions. However, securing a wide frequency band that is not used for signal transmission between the frequency bands used by the signals in each direction is not preferable because it deteriorates the frequency utilization efficiency. Therefore, it is conceivable to make a part of the frequency bands in each direction overlap. In this case, since the overlapping frequency region becomes an interference factor, a process of separating each signal with an echo canceler circuit is performed.

Prior Art Documents

Non-Patent Documents

[0004]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the echo cancellation circuit has problems of large circuit scale and high power consumption.

[0006] The present disclosure provides a communication device, a communication system, and a communication method capable of efficiently transmitting a two-way signal with low power consumption.

Means for Solving the Problems

[0007] The communication device according to the present disclosure includes a communication unit that performs signal transmission with a communication partner device, and a communication control unit that changes a signal ratio in a first direction to the communication partner device and a signal ratio in a second direction from the communication partner device according to a signal transmission state with the communication partner device. The signal transmission state may include at least one of a state of performing initial setting, security authentication, and key exchange of the communication partner device, a state in which the communication partner device transmits a signal after the initial setting, security authentication, and key exchange of the communication partner device are completed, and a state of stopping signal transmission with the communication partner device. The signal transmission state may at least include a state of turning on the power of at least one of the communication partner device and the communication device, or resetting at least one of the communication partner device and the communication device, a state of performing initial setting, security authentication, and key exchange of the communication partner device, a state in which the communication partner device transmits a signal after the initial setting, security authentication, and key exchange of the communication partner device are completed, and a state of stopping signal transmission with the communication partner device.

[0008] The communication unit may switch between signal transmission in the first direction and signal transmission in the second direction by time-division of a predetermined fixed period as a unit.

[0009] The communication control unit may adjust the signal ratios in the first direction and the second direction for each of the fixed periods.

[0010] The communication control unit selects one from a plurality of signal ratio patterns representing the types of signal ratios in the first direction and the second direction according to the signal transmission state, The communication unit may switch between signal transmission in the first direction and signal transmission in the second direction by time-division based on the signal ratio pattern selected by the communication control unit.

[0011] It includes a storage unit that stores the plurality of signal ratio patterns, The communication control unit selects one from the plurality of signal ratio patterns stored in the storage unit according to the signal transmission state, The communication unit may transmit a signal indicating the signal ratio pattern selected by the communication control unit to the communication partner device.

[0012] The communication unit transmits and receives signals with a predetermined frame structure, The frame structure may include information indicating whether to allow a change in a count value that defines the timing for changing the signal ratios in the second direction and the first direction, information indicating the count value, the currently selected signal ratio pattern, the signal ratio pattern to be selected next, and information indicating whether to allow a change in the signal ratio.

[0013] The frame structure may be included in OAM (Operation Administration and Maintenance).

[0014] When changing the signal ratio in the first direction and the second direction, the communication control unit may change the signal ratio in the first direction and the second direction after a period that is n times (n is an integer of 2 or more) the fixed period has elapsed.

[0015] The communication control unit may change the signal ratio in the first direction and the second direction only when it receives a response from the communication partner device indicating approval of the change in the signal ratio pattern within a period that is n times the fixed period.

[0016] The communication unit transmits and receives a signal having a frame structure including one or more containers in which the transmitted and received signals are stored every fixed period. The communication control unit may adjust the number of the containers according to the signal transmission state.

[0017] The frame structure may include a synchronization signal, at least one of the containers transmitted and received within the fixed period, and a parity signal.

[0018] The communication control unit may set the signal ratio in the first direction and the signal ratio in the second direction to 1:1 at least in one of the following cases: when the communication device and the communication partner device perform security authentication and key exchange, when the communication device performs initial settings, and when the communication partner device performs initial settings.

[0019] The signal ratio may be a ratio of signal amounts or a usage ratio of signals.

[0020] The communication unit can transmit the captured video signal. The communication control unit may make the signal ratio in the second direction higher than the signal ratio in the first direction during the period of receiving the video signal from the communication partner device.

[0021] The communication unit receives the video signal transmitted from the communication partner device in units of video frames. The communication control unit may make the signal ratio in the second direction during the period of receiving the video signal within one video frame higher than the signal ratio in the second direction during the vertical blanking period after receiving the video signal within one video frame.

[0022] The communication unit transmits the video signal to the communication partner device in units of video frames, The communication control unit may stop the signal transmission in the first direction and the second direction during the vertical blanking period after transmitting the video signal within one video frame.

[0023] The communication unit can transmit a video signal to be displayed on the display unit of the communication partner device or to be processed by the processing unit of the communication partner device, The communication control unit may make the signal ratio in the second direction during the period of transmitting the video signal to the communication partner device higher than the signal ratio in the first direction.

[0024] The communication partner device may be a slave device that performs signal transmission with the communication unit based on an instruction from the communication control unit.

[0025] The communication partner device may be a master device that performs signal transmission with the communication unit based on an instruction from the communication control unit.

[0026] The communication system according to the present disclosure is a master device, a slave device that performs signal transmission with the master device according to an instruction from the master device, and includes the master device and the slave device change the signal ratio in the first direction from the master device to the slave device and the signal ratio in the second direction from the slave device to the master device according to the signal transmission state between the master device and the slave device.

[0027] The communication method according to the present disclosure is performing signal transmission between the master device and the slave device according to an instruction from the master device, The master device and the slave device change the signal ratio in the first direction from the master device to the slave device and the signal ratio in the second direction from the slave device to the master device according to the signal transmission state between the master device and the slave device.

Brief Description of Drawings

[0028]

Figure 1

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Embodiments for Carrying Out the Invention

[0029] Hereinafter, embodiments of a communication device and a communication system will be described with reference to the drawings. Hereinafter, the description will focus on the main components of the communication device and the communication system, but there may be components and functions that are not illustrated or described in the communication device and the communication system. The following description does not exclude components and functions that are not illustrated or described.

[0030] (First Embodiment) FIG. 1 is a block diagram showing a schematic configuration of a communication system 2 including communication devices 1a and 1b according to the first embodiment. The communication system 2 in FIG. 1 includes a master device 3 and a slave device 4. In this specification, each of the master device 3 and the slave device 4 may be referred to as a communication device 1a or 1b. In FIG. 1, the flow of signals when transmitting a video signal from the slave device 4 to the master device 3 is indicated by an arrow. As will be described later, the communication system 2 in FIG. 1 may transmit a video signal from the master device 3 to the slave device 4.

[0031] The master device 3 and the slave device 4 in FIG. 1 are connected by a single cable 5, and signals are transmitted bidirectionally via this cable 5. More specifically, the master device 3 and the slave device 4 transmit signals bidirectionally using the TDD (Time Division Duplexing) method. In FIG. 1, the signal transmission from the master device 3 to the slave device 4 is called the Reverse channel, and the signal transmission from the slave device 4 to the master device 3 is called the Forward channel.

[0032] The master device 3 includes a host unit 6 and a Master SerDes unit 7. The host unit 6 transmits a transmission signal to be transmitted to the slave device 4 to the Master SerDes unit 7. Also, the host unit 6 transmits and receives control signals to and from the Master SerDes unit 7. The transmission and reception of control signals between the host unit 6 and the Master SerDes unit 7 are performed by, for example, I2C (Inter-Integrated Circuit) communication or GPIO (General Purpose Input / Output).

[0033] The Master SerDes unit 7 converts the parallel signal transmitted from the host unit 6 into a serial signal and transmits it to the slave device 4 via the cable 5. Also, the Master SerDes unit 7 receives the serial signal transmitted from the slave device 4 via the cable 5, converts it into a parallel signal, and transmits it to the host unit 6. In this way, the Master SerDes unit 7 functions as a communication unit that performs signal transmission with the slave device 4, which is the communication partner device.

[0034] The Master SerDes unit 7 includes a first MUX unit 8, a first receiving unit (Fw. Rx) 9, a first transmitting unit (Rv. Tx) 10, and a first LINK unit 11.

[0035] The first MUX unit 8 switches between the serial signal from the slave device 4 received via the cable 5 and the serial signal output from the first transmitting unit 10 according to the time division during the TDD cycle.

[0036] The first receiving unit 9 receives the serial signal (or multi - value signal) transmitted from the Slave SerDes unit 13 via the cable 5, performs equalization processing and error detection or error correction processing if necessary, and then converts it into a parallel signal and returns it to the original frame structure (see FIG. 7 described later). The first transmitting unit 10 converts the parallel signal having the frame structure of FIG. 7 described later into a serial signal or performs modulation in the case of a multi - value signal such as PAM4, and supplies it to the first MUX unit 8.

[0037] The first LINK unit 11 switches between the process of transmitting the transmission signal output from the host unit 6 to the first transmitting unit 10 and the process of transmitting the decoded signal output from the first receiving unit 9 to the host unit 6 according to time.

[0038] The slave device 4 includes a sensor 12 and a Slave SerDes unit 13. The sensor 12 includes one or more sensors. For example, the sensor 12 includes an image sensor that outputs, for example, a captured video signal. The sensor 12 outputs a parallel signal including a video signal or the like. Also, the sensor 12 transmits and receives control signals to and from the Slave SerDes unit 13. The transmission and reception of control signals between the sensor 12 and the Slave SerDes unit 13 are performed, for example, by I2C communication or GPIO.

[0039] The Slave SerDes unit 13 includes a second MUX unit 14, a second receiving unit (Rv. Rx) 15, a second transmitting unit (Fw. Tx) 16, and a second LINK unit 17.

[0040] The second MUX unit 14 switches between the serial signal from the master device 3 received via the cable 5 and the serial signal output from the second transmission unit 16 according to the time division during the TDD cycle.

[0041] The second reception unit 15 receives the serial signal (or multi-valued signal) transmitted from the Master SerDes unit 7 via the cable 5, performs equalization processing and error detection or error correction processing as necessary, and then converts it into a parallel signal and returns it to the frame structure of FIG. 7 described later. The second transmission unit 16 converts the parallel signal having the frame structure of FIG. 7 described later into a serial signal or performs modulation in the case of a multi-valued signal such as PAM4, and supplies it to the second MUX unit 14.

[0042] The second LINK unit 17 switches between the process of transmitting the parallel signal output from the sensor 12 to the second transmission unit 16 and the process of transmitting the decoded signal output from the second reception unit 15 to the sensor 12 according to time.

[0043] The host unit 6 functions as a communication control unit that controls the Master SerDes unit 7. More specifically, the host unit 6 can change the signal ratio in the downstream direction (first direction) to the slave device 4 and the signal ratio in the upstream direction (second direction) from the slave device 4 according to the signal transmission state with the slave device 4. The signal ratio changed by the host unit 6 is sent to the Master SerDes unit 7. The Master SerDes unit 7 stores its own signal ratio in the storage unit 11a and transmits a signal including the signal ratio of the slave device 4 to the slave device 4 via the cable 5. The slave device 4 stores the received signal ratio in the storage unit 17a in the Slave SerDes unit 13, for example. The storage units 11a and 17a can be configured by, for example, registers or semiconductor memories.

[0044] Here, the signal ratio mainly refers to the ratio of the signal amounts, but may also refer to the usage ratio of the signals. Further, the signal transmission state may include at least one of a state in which initial settings, security authentication, and key exchange are performed for a communication partner device (for example, slave device 4), a state in which the communication partner device transmits a signal after the initial settings, security authentication, and key exchange of the communication partner device are completed, and a state in which signal transmission with the communication partner device is stopped. Alternatively, the signal transmission state may include at least one of a state in which the communication partner device (for example, slave device 4) is powered on or reset, a state in which initial settings, security authentication, and key exchange are performed for the communication partner device, a state in which the communication partner device transmits a signal after the initial settings, security authentication, and key exchange of the communication partner device are completed, and a state in which signal transmission with the communication partner device is stopped.

[0045] Note that the control of the signal ratio between the master device 3 and the slave device 4 may be performed by the slave device 4 instead of the master device 3. In this case, a communication control unit is provided in the slave device 4. Hereinafter, an example in which the host unit 6 in the master device 3 functions as the communication control unit will be mainly described.

[0046] When switching the signal ratio between the master device 3 and the slave device 4, the host unit 6 may change the signal ratios in the downlink direction and the uplink direction after a period that is n times (n is an integer of 2 or more) the fixed period has elapsed when changing the signal ratios in the downlink direction and the uplink direction. In this case, the host unit 6 may change the signal ratios in the downlink direction and the uplink direction only when a response indicating acceptance of the change in the signal ratio pattern is received from the communication partner device within the period that is n times the fixed period.

[0047] FIGS. 2A and 2B are diagrams for explaining the TDD method. In the TDD method, signal transmission from the master device 3 to the slave device 4 and signal transmission from the slave device 4 to the master device 3 are performed in a time-division manner. More specifically, with a predetermined fixed period as a unit, the fixed period is time-divided to switch between signal transmission from the master device 3 to the slave device 4 and signal transmission from the slave device 4 to the master device 3.

[0048] Figure 2A is a diagram showing the uplink signal transmission period from the slave device 4 to the master device 3 and the downlink signal transmission period from the master device 3 to the slave device 4 in the TDD mode. In Figure 2A, the above-described fixed period is referred to as 1 TDD cycle. Within 1 TDD cycle, the uplink signal transmission period and the downlink signal transmission period are provided so as not to overlap. In the example of Figure 2A, an example is shown in which the signal transmission period of the downlink signal (referred to as Rv or Reverse channel) from the master device 3 to the slave device 4 is extremely shorter than the signal transmission period of the uplink signal (referred to as Fw or Forward channel) from the slave device 4 to the master device 3, that is, an example in which the signal ratio of signal Rv is extremely smaller than the signal ratio of signal Fw. For example, when transmitting the video signal captured by the sensor 12 in the slave device 4 to the master device 3, the signal ratio is as shown in Figure 2A.

[0049] Figure 2B is a diagram showing the frequency band used for uplink signal transmission and the frequency band used for downlink signal transmission in the TDD mode. The horizontal axis of Figure 2B is frequency, and the vertical axis is signal strength. As shown in Figure 2B, in the uplink Fw signal transmission and the downlink Rv signal transmission, most of the frequency bands overlap. For example, when transmitting the video signal captured by the sensor 12 in the slave device 4 to the master device 3, since the uplink Fw signal transmission with a large signal amount requires a wider frequency band than the downlink Rv signal transmission, it is performed using a wider frequency band including the frequency band used for the downlink Rv signal transmission. In the TDD mode, as shown in Figure 2A, since the signal transmission period of the uplink signal Fw does not overlap with the signal transmission period of the downlink signal Rv, an echo canceler circuit for separating the two signals becomes unnecessary.

[0050] The master device 3 and the slave device 4 in FIG. 1 assume signal transmission in the TDD mode. However, in some cases, signal transmission may also be performed in the FDD mode. FIGS. 2C and 2D are diagrams for explaining the FDD mode. In the FDD mode, the frequency band used for signal transmission from the master device 3 to the slave device 4 is different from the frequency band used for signal transmission from the slave device 4 to the master device 3. Therefore, signal transmission from the master device 3 to the slave device 4 and signal transmission from the slave device 4 to the master device 3 can be performed at the same timing.

[0051] FIG. 2C is a diagram showing the uplink signal transmission period from the slave device 4 to the master device 3 and the downlink signal transmission period from the master device 3 to the slave device 4 in the FDD mode. As shown in the figure, both the uplink signal transmission and the downlink signal transmission are performed using the entire period within one FDD cycle.

[0052] FIG. 2D is a diagram showing the frequency band used for uplink signal transmission and the frequency band used for downlink signal transmission in the FDD mode. The horizontal axis in FIG. 2D is the frequency, and the vertical axis is the signal intensity. As shown in FIG. 2D, the uplink signal transmission with a large signal amount is performed using a wide frequency band on the high-frequency side. The downlink signal transmission with a small signal amount is performed using a narrow frequency band on the fixed-receipt side. In FIG. 2D, in order to improve the frequency utilization efficiency, the frequency band used for uplink signal transmission and the frequency band used for downlink signal transmission are partially overlapped. Due to this overlapping part, an echo cancellation circuit is required. The echo cancellation circuit is a circuit that accurately separates the uplink signal and the downlink signal.

[0053] FIG. 3 is a diagram showing the format of a signal output by an image sensor, which is an example of the sensor 12. An image sensor that captures a moving image repeats imaging at a cycle of, for example, 60 video frames or 120 video frames per second. One video frame data has a frame start (FS), packets for a plurality of horizontal lines, and a frame end (FE).

[0054] The packets of each horizontal line have a packet header (PH), pixel data for one horizontal line, and a packet footer (PF). In this specification, a packet may sometimes be referred to as a video signal.

[0055] One horizontal line period includes the transmission period of the above-described packet and a horizontal blanking period. The horizontal blanking period is about several percent to 10% of the length of one horizontal line period and is a period during which no video signal (packet) is transmitted.

[0056] One video frame period includes a plurality of horizontal line periods and a frame blanking period (also referred to as a vertical blanking period). The frame blanking period is about 10% of the length of one video frame period and is a period during which no video signal (packet) is transmitted.

[0057] When the slave device 4 transmits the video signal captured by the image sensor to the master device 3, it transmits the packets of each horizontal line in order from the topmost line according to the format of FIG. 3.

[0058] FIG. 4 is a diagram showing the timing of signals transmitted and received between the master device 3 and the slave device 4 when the slave device 4 includes an image sensor. When the power of the communication system 2 in FIG. 1 is turned on at time t1, then at a subsequent time t2, the master device 3 transmits a signal for initializing the slave device 4 and a control signal for performing security authentication and key exchange with the slave device 4 to the slave device 4 via the cable 5. When the initialization of the slave device 4 is completed and the security authentication and key exchange between the master device 3 and the slave device 4 are successful, from time t3, the slave device 4 starts transmitting the video signal via the cable 5. As shown in FIG. 3, the video signal transmitted by the slave device 4 includes blanking periods (t4 to t5) here and there. During the blanking period, there may be no signal, null data may be transmitted, or a signal other than the video signal may be transmitted.

[0059] During the time period from t3 to t4, a video signal for one video frame is transmitted. When the master device 3 changes the operating state of the slave device 4, for example, when changing the operation mode of the image sensor, within the frame blanking period after transmitting the video signal for one video frame, the master device 3 transmits a control signal to the slave device 4 via the cable 5. The slave device 4 that has received the control signal can change, for example, the operation mode of the image sensor according to the content of the control signal. The control signal from the master device 3 may be transmitted during the horizontal blanking period within one horizontal line period.

[0060] In this way, since the master device 3 transmits the control signal for controlling the slave device 4 during the frame blanking period or the horizontal blanking period, it is possible to transmit and receive the control signal with the slave device 4 without adversely affecting the transmission of the video signal.

[0061] In the communication system 2 according to the present embodiment, according to the signal transmission state between the master device 3 and the slave device 4, the downlink signal ratio transmitted from the master device 3 to the slave device 4 and the uplink signal ratio transmitted from the slave device 4 to the master device 3 are changed. The control for changing the signal ratio is performed, for example, by the host unit 6 in the master device 3. Alternatively, this control may be performed by the slave device 4.

[0062] FIG. 5 is a diagram showing in detail the signal ratio when transmitting a video signal from the slave device 4 to the master device 3. The upper part of FIG. 5 shows the signal (Fw, Forward channel) transmitted from the slave device 4 to the master device 3, and the lower part shows the signal (Rv, Reverse channel) transmitted from the master device 3 to the slave device 4. As shown in the figure, at times t1 to t2, for example, a control signal is transmitted from the master device 3 to the slave device 4. The control signal is, for example, a signal for initializing the slave device 4. The time period from t2 to t3 is a signal-free period.

[0063] Thereafter, from time t3 to t4, a video signal is transmitted from the slave device 4 to the master device 3. Here, for example, a video signal for one video frame is transmitted. Time t1 to t4 is one TDD cycle, and thereafter, the signal Fw and the signal Rv are switched and transmitted in a time-division manner at a predetermined signal ratio for each TDD cycle.

[0064] In the example of FIG. 5, the signal ratio of the signal transmitted from the slave device 4 to the master device 3 is overwhelmingly larger than the signal ratio of the signal transmitted from the master device 3 to the slave device 4. This is because the amount of the video signal transmitted from the slave device 4 to the master device 3 is large. As will be described later, outside the signal transmission state for transmitting the video signal, the signal ratio of the signals transmitted and received between the master device 3 and the slave device 4 may be different from that in FIG. 5.

[0065] FIG. 6 is a flowchart showing an example of the processing procedure of the communication system 2 in FIG. 1. This flowchart shows the processing procedure when an image sensor is provided on the slave device 4 side and a video signal captured by the image sensor is transmitted from the slave device 4 to the master device 3. The master device 3 is, for example, an ECU (Electronic Control Unit) mounted on a vehicle, and the slave device 4 is a camera equipped with an image sensor.

[0066] First, turn on or reset the power supply of the communication system 2 in FIG. 1 (step S1). Next, synchronize the physical layer between the master device 3 and the slave device 4 to establish the connection between the Master SerDes unit 7 and the Slave SerDes unit 13 (step S2). Next, perform security authentication and key exchange between the master device 3 and the slave device 4 (step S3). Here, for example, the master device 3 and the slave device 4 mutually authenticate that each other is a legitimate communication partner. For example, they mutually send and receive an authentication protocol such as SSL / TLS, and after establishing mutual authentication, they perform key exchange to share a secret key. Thereby, encrypted communication can be performed between the master device 3 and the slave device 4 hereafter. When performing the processes of steps S2 to S3, the amount of signals transmitted and received between the master device 3 and the slave device 4 is approximately equal, and the signal ratio of signal Fw and signal Rv is about 1:1.

[0067] Next, set the operation control register of at least one of the master device 3 and the slave device 4 (step S4). For example, information for appropriately operating the image sensor or camera of the slave device 4 is set in the operation control register. The operation control register is provided, for example, in at least one of the first LINK unit 11 and the second LINK unit 17. In FIG. 1, storage units 11a and 17a are provided in the first LINK unit 11 and the second LINK unit 17 respectively, but these storage units 11a and 17a may also serve as the operation control register. When the operation control register is provided in the slave device 4, the master device 3 transmits a control signal to the slave device 4 via the cable 5, and this control signal is used to set the operation control register in the slave device 4. Also, the slave device 4 transmits a response signal indicating whether the setting of the operation control register has been completed to the master device 3 via the cable 5. When performing the process of step S4, the amount of signal Rv transmitted from the master device 3 to the slave device 4 is much larger than the amount of signal Fw transmitted from the slave device 4 to the master device 3, and the signal ratio is also significantly different.

[0068] Next, the operation of the slave device 4 is started (step S5). If the slave device 4 is a camera, imaging by the image sensor is started. The slave device 4 sequentially transmits video signals to the master device 3 in video frame units (step S6). While the process of step S6 is being performed, the signal amount and signal ratio of the signal Fw transmitted from the slave device 4 to the master device 3 are much larger than the signal amount and signal ratio of the signal Rv transmitted from the master device 3 to the slave device 4.

[0069] Hereafter, except when an abnormality such as the loss of synchronization in the physical layer between the Master SerDes unit 7 and the Slave SerDes unit 13 occurs, the slave device 4 transmits video signals to the master device 3 in video frame units.

[0070] During the transmission of the video signal, it is monitored whether the above-described loss of synchronization in the physical layer or forced reset has occurred (step S7). If the loss of synchronization or forced reset has occurred, the processes after step S2 are performed. Also, it is monitored whether the power supply of at least one of the master device 3 and the slave device 4 has been turned off (step S8). If the power supply has been turned off, the process of FIG. 6 is terminated.

[0071] During the continuation of the processes of steps S5 to S6, it is determined whether there is a need to change the operation of the communication system 2 in FIG. 1 (step S9). If there is no need to change the operation, the operations after step S6 are continued. If there is a need to change the operation, the setting of the operation control register of at least one of the master device 3 and the slave device 4 is changed (step S10). Thereafter, the processes after step S5 are continued.

[0072] As described above, in the present embodiment, the signal ratio of the signal Rv from the master device 3 to the slave device 4 and the signal ratio of the signal Fw from the slave device 4 to the master device 3 are changed according to the signal transmission state of the communication system 2 in FIG. 1. For example, as shown in FIG. 5, when transmitting a video signal from the slave device 4 to the master device 3, the signal ratio of the signal Fw becomes overwhelmingly larger than the signal ratio of the signal Rv. However, if the signal ratio in this case is always maintained, when it is necessary to transmit and receive signals evenly between the master device 3 and the slave device 4 as in step S2 of FIG. 6, or when the signal amount of the signal Rv is larger than the signal amount of the signal Fw as in step S4 of FIG. 6, it takes time to transmit a signal from the master device 3 to the slave device 4, and it takes extra time for the initial setting, security authentication, and key exchange of the slave device 4, or the setting of the operation control register of the slave device 4 cannot be performed quickly, resulting in a decrease in communication efficiency.

[0073] The video signal in step S6 of FIG. 6 is transmitted in video frame units, and there is a frame blanking period for each video frame. Even if a video signal is transmitted from the slave device 4 to the master device 3 during this frame blanking period, the master device 3 does not use the video signal within the frame blanking period. Therefore, it is desirable not to transmit a video signal from the slave device 4 to the master device 3 during the frame blanking period. Therefore, it is desirable to stop the transmission of the video signal from the slave device 4 to the master device 3 during the frame blanking period, and instead, enable the master device 3 to transmit a control signal or the like for changing the operation of the slave device 4 to the slave device 4.

[0074] In this way, when signal transmission is performed between the master device 3 and the slave device 4 in the TDD mode, the amount of signals transmitted and received between the master device 3 and the slave device 4 varies greatly depending on the signal transmission state. Therefore, by making the signal ratio of the signals transmitted and received between the master device 3 and the slave device 4 variable according to the signal transmission state, the communication efficiency can be improved and the power consumption can also be reduced.

[0075] FIG. 7 is a diagram showing an example of the frame structure of signals transmitted and received between the master device 3 and the slave device 4. The frame structure of the signal transmitted from the master device 3 to the slave device 4 is the same as the frame structure of the signal transmitted from the slave device 4 to the master device 3, and is shown in FIG. 7.

[0076] The frame structure of FIG. 7 includes a plurality of containers between the Sync pattern and the Parity. The Sync pattern is a signal pattern for synchronizing the physical layers of the Master SerDes unit 7 and the Slave SerDes unit 13. The plurality of containers includes, for example, about 2 to 100 containers. The number of containers included in the frame structure changes according to the signal transmission state. Parity is a bit or a bit string for error detection or error correction processing.

[0077] The structure of the container includes a Header, a Payload, and a Parity. The Header includes address information indicating the destination of the Payload, etc. The Payload is the main body part of the signal to be transmitted and received. The Payload includes OAM (Operations, Administration, Maintenance) for SerDes control in addition to the video signal. Parity is a bit or a bit string for error detection or error correction processing of the Payload.

[0078] To change the signal ratio of the signal Rv from the master device 3 to the slave device 4 and the signal ratio of the signal Fw from the slave device 4 to the master device 3 within one TDD cycle, it can be achieved by changing the number of containers included in each frame structure. Note that for the signals Rv and Fw, the sizes of the containers may be the same or different.

[0079] FIG. 8 is control information (hereinafter referred to as frame structure control information) for controlling the signal ratio from the master device 3 to the slave device 4 and the signal ratio from the slave device 4 to the master device 3 in one TDD cycle, and is a diagram showing the control information included in the transmission frame structure and transmitted. This frame structure control information is included in OAM.

[0080] As shown in FIG. 8, the frame structure control information includes Count Down EN / DS, Count Down, Current Pattern, Next Pattern, and OK / NG. Count Down EN / DS is information indicating whether the count-down value for counting the number of TDD cycles until the signal ratio of the signal Rv from the master device 3 to the slave device 4 and the signal Fw from the slave device 4 to the master device 3 is changed is functioning properly. When it is functioning properly, it becomes EN meaning Enable, and when the function has stopped, it becomes DS meaning Disable. In this embodiment, it is counted down from the initial value of the counter for each TDD cycle, and when the count value becomes zero, the signal ratio of the signal Rv and the signal Fw is changed.

[0081] Count Down indicates the number of TDD cycles until the signal ratio of the signal Rv and the signal Fw is changed, and is the count value after the count-down. When Count Down becomes zero from 1, the signal Rv and the signal Fw are switched to a new signal ratio.

[0082] Current pattern is a signal ratio pattern representing the current signal ratio of the signals Rv and Fw being transmitted. FIG. 9 is a diagram showing an example of the types of signal ratio patterns. Patten #1 is a signal ratio pattern in which the signal ratio of the signals Rv and Fw is approximately 1:1 and the signal-free period within one TDD cycle is long. Pattern #1 is selected when the number of containers included in the signals Rv and Fw is about several each, and information for maintaining synchronization between the master device 3 and the slave device 4 is transmitted and received.

[0083] Pattern #2 is a signal ratio pattern where the signal ratio of signal Fw is extremely larger than that of signal Rv. Pattern #2 is selected when a large amount of video signals are transmitted from the slave device 4 to the master device 3, etc.

[0084] Pattern #3 has a signal ratio of signal Rv and signal Fw of approximately 1:1. Pattern #3 is selected when transmitting a control signal for setting an operation control register from the master device 3 to the slave device 4, or when performing security authentication and key exchange between the master device 3 and the slave device 4.

[0085] Pattern #4 is a signal ratio pattern where the entire 1 TDD cycle is a signal-free period. Pattern #4 is selected when stopping the transmission of signal Rv and signal Fw.

[0086] OK / NG means that when the slave device 4 or the master device 3 that has received the frame structure control information with Count Down EN / DS being EN from the master device 3 or the slave device 4 that wants to change the signal ratio of signal Rv and signal Fw agrees to change the signal ratio, it returns OK; otherwise, it returns NG.

[0087] FIG. 10 is a diagram showing a first example of control for changing the signal ratio of signal Rv and signal Fw during 1 TDD cycle. FIG. 10 shows an example of changing the signal ratio when switching from the state of performing security authentication, key exchange, and setting of the operation control register between the master device 3 and the slave device 4 to the state of transmitting video signals from the slave device 4 to the master device 3.

[0088] FIG. 10 shows an example of setting the initial value of the counter to 2 during the period of performing security authentication, key exchange, and setting of the operation control register, counting down every TDD cycle, and changing the signal ratio when the count value becomes zero.

[0089] The 1 TDD cycle from time t1 to t2, the 1 TDD cycle from time t2 to t3, and the 1 TDD cycle from time t3 to t4 are periods for performing security authentication, key exchange, and setting the operation control register. In the 1 TDD cycle from time t1 to t2, in the frame structure control information of signal Rv, Count Down EN / DS is Disable, Count Down is zero, Current Pattern is Pattern #3, Next Pattern is Pattern #3, and OK / NG is don't care. For signal Fw, Count Down EN / DS is Disable, Count Down is zero, Current Pattern is Pattern #3, Next Pattern is Pattern #2, and OK / NG is OK.

[0090] In the 1 TDD cycle from time t2 to t3, in the frame structure control information of signal Rv, Count Down EN / DS is Enable, Count Down is 2, Current Pattern is Pattern #3, Next Pattern is Pattern #2, and OK / NG is don't care. For signal Fw, Count Down EN / DS is Enable, Count Down is 2, Current Pattern is Pattern #3, Next Pattern is Pattern #2, and OK / NG is OK.

[0091] In the 1 TDD cycle from time t3 to t4, Count Down in the frame structure control information of signal Rv changes to 1. Also, Count Down of signal Fw also changes to 1.

[0092] In the 1 TDD cycle from time t4 to t5, in the frame structure control information of signal Rv, Count Down EN / DS is Disable, Count Down is zero, Current Pattern is Pattern #2, Next Pattern is Pattern #2, and OK / NG is don't care. For signal Fw, Count Down EN / DS is Disable, Count Down is zero, Current Pattern is Pattern #2, Next Pattern is Pattern #2, and OK / NG is OK.

[0093] As described above, within the period from time t1 to t3, since the Current Pattern is Pattern #3, as shown in FIG. 9, a signal ratio suitable for setting the operation control register, security authentication, and key exchange between the master device 3 and the slave device 4 is selected. Also, when time t4 arrives, since the Count down becomes zero, the Current Pattern switches from Pattern #3 to Pattern #2, resulting in a signal ratio suitable for transmitting a large amount of video signals from the slave device 4 to the master device 3.

[0094] FIG. 11 is a diagram showing a second example of control for changing the signal ratio of signal Rv and signal Fw during a 1 TDD cycle. FIG. 11 shows an example of switching the signal ratio during the frame blanking period between transmissions of video signals from the slave device 4 to the master device 3.

[0095] The 1 TDD cycle from time t1 to t2, the 1 TDD cycle from time t2 to t3, and the 1 TDD cycle from time t3 to t4 are periods for transmitting video signals from the slave device 4 to the master device 3. After time t4, it is a period for transmitting signals other than video signals between the master device 3 and the slave device 4, such as switching the signal ratio during the frame blanking period.

[0096] In one TDD cycle from time t1 to t2, in the frame structure control information of signal Rv, Count Down EN / DS is Disable, Count Down is zero, Current Pattern is Pattern #2, Next Pattern is Pattern #2, and OK / NG is don't care. For signal Fw, Count Down EN / DS is Enable, Count Down is 3, Current Pattern is Pattern #2, Next Pattern is Pattern #1, and OK / NG is OK.

[0097] In one TDD cycle from time t2 to t3, in the frame structure control information of signal Rv, Count Down EN / DS is Enable, Count Down is 2, Current Pattern is Pattern #2, Next Pattern is Pattern #1, and OK / NG is don't care. For signal Fw, Count Down EN / DS is Enable, Count Down is 2, Current Pattern is Pattern #2, Next Pattern is Pattern #1, and OK / NG is OK.

[0098] In one TDD cycle from time t3 to t4, Count Down in the frame structure control information of both signal Rv and signal Fw becomes 1.

[0099] In one TDD cycle from time t4 to t5, in the frame structure control information of signal Rv, Count Down EN / DS is Disable, Count Down is zero, Current Pattern is Pattern #1, Next Pattern is Pattern #1, and OK / NG is don't care. For signal Fw, Count Down EN / DS is Disable, Count Down is zero, Current Pattern is Pattern #1, Next Pattern is Pattern #1, and OK / NG is don't care.

[0100] In this way, the slave device 4 transmits the video signal to the master device 3 in video frame units. For each video frame, a frame blanking period is provided after transmitting the video signals of all lines in the video frame. Since no valid video signal is transmitted from the slave device 4 during the frame blanking period, this period can be used for other signal transmissions. For example, it can be used to transmit a control signal for the master device 3 to switch the operation mode of the slave device 4.

[0101] In the above description, an example of switching the signal ratio during the frame blanking period has been described. However, as shown in FIG. 3, since each horizontal line has a horizontal blanking period, the signal ratio can also be switched during this horizontal line blanking period.

[0102] In the above description, an example of transmitting the video signal captured by the image sensor in the slave device 4 to the master device 3 via the cable 5 from the slave device 4 to the master device 3 has been described. However, this embodiment is also applicable, for example, when the slave device 4 has a display unit or a processing unit, and the video signal is transmitted from the master device 3 to the slave device 4 via the cable 5 and is displayed on the display unit or processed by the processing unit. In this case, a new signal ratio pattern in which the signal ratio of the signal Rv is overwhelmingly larger than the signal ratio of the signal Fw is provided, and when transmitting the video signal from the master device 3 to the slave device 4, this newly provided signal ratio pattern is selected.

[0103] When displaying the video signal on the display unit, since there are horizontal blanking periods and frame blanking periods, signals other than the video signal may be transmitted and received between the master device 3 and the slave device 4 during these blanking periods. For example, a signal for switching the display resolution of the display unit may be transmitted and received.

[0104] As described above, in the first embodiment, when signal transmission is performed between the master device 3 and the slave device 4 using the TDD method, the signal ratio of the signal Rv transmitted from the master device 3 to the slave device 4 and the signal ratio of the signal Fw transmitted from the slave device 4 to the master device 3 are switched according to the signal transmission state. Thereby, efficient signal transmission can be performed between the master device 3 and the slave device 4, and power consumption can also be reduced.

[0105] In particular, since the signal ratios of the signal Fw and the signal Rv can be greatly changed according to the signal transmission state, a large amount of signals can be transmitted in a short time, and high-speed transmission can be realized.

[0106] Also, by switching the signal ratio during the frame blanking period or the horizontal blanking period between the times when the slave device 4 transmits a video signal to the master device 3, various signals other than the video signal can be efficiently transmitted between the master device 3 and the slave device 4 without adversely affecting the transmission of the video signal.

[0107] (Second Embodiment) In the second embodiment, the frame structure control information of the signal is different from that of the first embodiment. The communication system 2 according to the second embodiment is configured in the same manner as in FIG. 1. Also, the system according to the second embodiment performs signal transmission between the master device 3 and the slave device 4 in the same processing procedure as in FIG. 6.

[0108] In the communication system 2 according to the second embodiment, the frame structure of the signals transmitted and received by the master device 3 and the slave device 4 is the same as in FIG. 7, but the frame structure control information is different from that in FIG. 8.

[0109] FIG. 12 is a diagram showing frame structure control information of the second embodiment. The frame structure control information in FIG. 12 is also included in, for example, OAM. As shown in FIG. 12, the frame structure control information of the second embodiment includes Count Down EN / DS, Count Down, Current Fw Number of Container, Current Rv Number of Container, Next Fw Number of Container, Next Rv Number of Container, and OK / NG. Current Fw Number of Container is the number of containers included in the current signal Fw. Current Rv Number of Container is the number of containers included in the current signal Rv. Next Fw Number of Container is the number of containers included in the signal Fw when the signal ratio is changed next. Next Rv Number of Container is the number of containers included in the signal Rv when the signal ratio is changed next.

[0110] Since the frame structure control information of FIG. 8 described above includes a signal ratio pattern and it is known that there are a plurality of types of signal ratio patterns as shown in FIG. 9, the number of containers of signal Rv and signal Fw can be specified by the signal ratio pattern in the frame structure control information. On the other hand, in the second embodiment, since the information on the number of containers is directly included in the frame structure control information, the signal ratio of signal Fw and signal Rv can be easily specified without using the signal ratio pattern.

[0111] After starting signal transmission between the master device 3 and the slave device 4, for some reason, signal transmission may be temporarily stopped and then restarted. In such a case, after stopping signal transmission, it may be possible to specify in the frame structure control information how much time has elapsed before restarting signal transmission.

[0112] FIG. 13 is a diagram showing an example of adding information regarding restart of signal transmission to the frame structure control information of FIG. 8. The frame structure control information of FIG. 13 includes a Restart count and a Restart Pattern between the Next pattern and OK / NG in the frame structure control information of FIG. 8. The Restart count is the number of TDD cycles from when signal transmission is stopped until signal transmission is started. The Restart Pattern is the type of signal ratio pattern when restarting signal transmission.

[0113] FIG. 14 is a diagram showing an example of adding information regarding restart of signal transmission to the frame structure control information of FIG. 12. The frame structure control information of FIG. 14 has a Restart count, a Restart Fw Number of Container, and a Restart Rv Number of Container between the Next Rv Number of Container and OK / NG in the frame structure control information of FIG. 12. The Restart Fw Number of Container is the number of signal Fw containers when restarting signal transmission. The Restart Rv Number of Container is the number of signal Rv containers when restarting signal transmission.

[0114] FIG. 15 is a diagram showing an example of restarting signal transmission after stopping it. The time periods from time t1 to t2 and from time t2 to t3 in FIG. 15 are periods during which the slave device 4 transmits a video signal to the master device 3. The time period from time t3 to t4 is a frame blanking period. An example of restarting signal transmission after the frame blanking period ends is shown.

[0115] In the 1 TDD cycle from time t1 to t2 in FIG. 15, in the frame structure control information of signal Rv, Count Down EN / DS is Enable, Count Down is 2, Current Pattern is Pattern #2, Next Pattern is Pattern #4, Restart count is 10, Restart Pattern is Pattern #2, and OK / NG is don't care. For signal Fw, Count Down EN / DS is Enable, Count Down is 2, Current Pattern is Pattern #2, Next Pattern is Pattern #4, Restart count is 10, Restart Pattern is Pattern #2, and OK / NG is OK.

[0116] In the 1 TDD cycle from time t2 to t3, the Count Down of the frame structure control information for both signal Rv and signal Fw becomes 1.

[0117] Thereafter, the period from time t3 to t4 is a frame blanking period, and Pattern #4 is selected as the signal ratio pattern during this period. As shown in FIG. 9, Pattern #4 indicates that no signal transmission is performed, and signal transmission is stopped. Therefore, the Restart count value counts up from 0 for each TDD cycle, and at time t4 when the count value reaches 9, it becomes the 10 counts specified by the Restart count in the frame structure control information. Thus, the signal ratio of signal Rv and signal Fw is set to the Pattern #2 specified by the Restart Pattern in the frame structure control information, and the transmission of the video signal from the slave device 4 to the master device 3 is restarted.

[0118] FIG. 15 shows an example in which the information of the signal ratio pattern is included in the frame structure control information, but the information of the number of containers may be included as shown in FIG. 14.

[0119] Thus, in the second embodiment, since the number of containers of the signal Rv and the signal Fw is specified by the frame structure control information, the signal ratio of the signal Rv and the signal Fw can be easily set.

[0120] Also, in the second embodiment, when the signal transmission is once stopped during the signal transmission and then the signal transmission is resumed, since the timing of resuming the signal transmission and the signal ratio at the time of resumption are set in the frame structure control information, the resumption of the signal transmission can be performed smoothly.

[0121] Note that the present technology can take the following configuration. (1) The communication device includes a communication unit that performs signal transmission with a communication partner device, and a communication control unit that changes the signal ratio in the first direction to the communication partner device and the signal ratio in the second direction from the communication partner device according to the signal transmission state with the communication partner device. (2) In the communication device according to (1), the signal transmission state includes at least one of a state in which the communication partner device and the communication device perform initial setting, security authentication, and key exchange, a state in which the communication partner device transmits a signal after the initial setting, security authentication, and key exchange of the communication partner device are completed, and a state in which signal transmission between the communication partner device and the communication device is stopped. (3) In the communication device according to (1), the signal transmission state includes at least a state in which at least one of the communication partner device and the communication device is powered on, or at least one of the communication partner device and the communication device is reset, a state in which the communication partner device and the communication device perform initial setting, security authentication, and key exchange, a state in which the communication partner device transmits a signal after the initial setting, security authentication, and key exchange of the communication partner device are completed, and a state in which signal transmission between the communication partner device and the communication device is stopped. (4) In the communication device according to any one of (1) to (3), The communication unit switches between signal transmission in the first direction and signal transmission in the second direction by time-division of a predetermined fixed period as a unit. (5) In the communication device according to (4), The communication control unit adjusts the signal ratio in the first direction and the second direction for each fixed period. (6) In the communication device according to (4) or (5), The communication control unit selects one from a plurality of signal ratio patterns representing the types of signal ratios in the first direction and the second direction according to the signal transmission state, The communication unit switches between signal transmissions in the first direction and the second direction by time-division based on the signal ratio pattern selected by the communication control unit. (7) In the communication device according to (6), It includes a storage unit that stores the plurality of signal ratio patterns, The communication control unit selects one from the plurality of signal ratio patterns stored in the storage unit according to the signal transmission state, The communication unit transmits a signal including the signal ratio pattern selected by the communication control unit to the communication partner device. (8) In the communication device according to (6) or (7), The communication unit transmits and receives signals with a predetermined frame structure, The frame structure includes information indicating whether to allow a change in a count value that defines the timing for changing the signal ratios in the second direction and the first direction, information indicating the count value, the signal ratio pattern being selected, the signal ratio pattern to be selected next, and information indicating whether to allow a change in the signal ratio. (9) In the communication device according to (8), The frame structure is included in OAM (Operation Administration and Maintenance). (10) In the communication device according to any one of (4) to (9), When changing the signal ratio in the first direction and the second direction, the communication control unit changes the signal ratio in the first direction and the second direction after a period that is n times (n is an integer of 2 or more) the fixed period has elapsed. In the communication device according to (11)(10), The communication control unit changes the signal ratio in the first direction and the second direction only when it receives a response from the communication partner device indicating approval of the change in the signal ratio pattern within a period that is n times the fixed period. In the communication device according to (12)(4) or (5), The communication unit transmits and receives a signal having a frame structure including one or more containers in which the transmitted and received signals are stored every fixed period. The communication control unit adjusts the number of the containers according to the signal transmission state. In the communication device according to (13)(12), The frame structure includes a synchronization signal, at least one of the containers transmitted and received within the fixed period, and a parity signal. In the communication device according to any one of (14)(4) to (13), The communication control unit sets the signal ratio in the first direction and the signal ratio in the second direction to 1:1 at least in one of when the communication device and the communication partner device perform security authentication and key exchange, when the communication device performs initial setting, and when the communication partner device performs initial setting. In the communication device according to any one of (15)(1) to (14), The signal ratio is a ratio of signal amounts or a usage ratio of signals. In the communication device according to any one of (16)(1) to (15), The communication unit can transmit the captured video signal. The communication control unit makes the signal ratio in the second direction higher than the signal ratio in the first direction during the period of receiving the video signal from the communication partner device. In the communication device according to (17)(16), The communication unit receives a video signal transmitted from the communication partner device in units of video frames, The communication control unit makes the signal ratio in the second direction during the period of receiving the video signal within one video frame higher than the signal ratio in the second direction during the vertical blanking period after transmitting the video signal within one video frame. (18)(16) In the communication device according to the above, The communication unit transmits a video signal to the communication partner device in units of video frames, The communication control unit stops the signal transmission in the first direction and the second direction during the vertical blanking period after transmitting the video signal within one video frame. (19)(1) In the communication device according to any one of (18), The communication unit can transmit a video signal to be displayed on the display unit of the communication partner device or to be processed by the processing unit of the communication partner device, The communication control unit makes the signal ratio in the second direction during the period of transmitting the video signal to the communication partner device higher than the signal ratio in the first direction. (20)(1) In the communication device according to any one of (19), The communication partner device is a slave device that performs signal transmission with the communication unit based on an instruction from the communication control unit. (21)(1) In the communication device according to any one of (19), The communication partner device is a master device that performs signal transmission with the communication unit based on an instruction from the communication control unit. (22) The communication system is A master device, A slave device that performs signal transmission with the master device according to an instruction from the master device, and is provided with, The master device and the slave device change the signal ratio in the first direction from the master device to the slave device and the signal ratio in the second direction from the slave device to the master device according to the signal transmission state between the master device and the slave device. (23) The communication method is In accordance with an instruction from the master device, signal transmission is performed between the master device and the slave device. The master device and the slave device change a signal ratio in a first direction from the master device to the slave device and a signal ratio in a second direction from the slave device to the master device according to a signal transmission state between the master device and the slave device.

[0122] At least a part of the communication device and the communication system described in the above-described embodiment may be configured by hardware or may be configured by software. When configured by software, a program for realizing at least a part of the functions of the communication device and the communication system may be stored in a recording medium such as a flexible disk or a CD-ROM, and read and executed by a computer. The recording medium is not limited to a removable one such as a magnetic disk or an optical disk, and may be a fixed-type recording medium such as a hard disk device or a memory.

[0123] Also, a program for realizing at least a part of the functions of the communication device and the communication system may be distributed via a communication line (including wireless communication) such as the Internet. Further, the program may be distributed in an encrypted, modulated, or compressed state via a wired or wireless line such as the Internet or stored in a recording medium.

[0124] Aspects of the present disclosure are not limited to the above-described individual embodiments, but include various modifications that can be conceived by those skilled in the art, and the effects of the present disclosure are not limited to the above-described content. That is, various additions, changes, and partial deletions are possible without departing from the conceptual ideas and spirits of the present disclosure derived from the content defined in the claims and their equivalents.

Description of Reference Numerals

[0125] 1a, 1b Communication devices, 2 Communication system, 3 Master device, 4 Slave device, 6 Host section, 7 Master SerDes section, 8 First MUX section, 9 First receiving section, 10 First transmitting section, 11 First LINK section, 11a Memory section, 12 Sensor, 13 Slave SerDes section, 14 Second MUX section, 15 Second receiving section, 16 Second transmitting section, 17 Second LINK section, 17a Memory section

Claims

1. A communication unit that performs signal transmission with a communication partner device, A communication control unit that changes a signal ratio in a first direction to the communication partner device and a signal ratio in a second direction from the communication partner device according to a signal transmission state with the communication partner device, The communication unit switches between signal transmission in the first direction and signal transmission in the second direction by time-division of a predetermined fixed period as a unit. The communication control unit adjusts signal ratios in the first direction and the second direction for each fixed period. A communication device.

2. The signal transmission state includes at least one of a state in which initial setting, security authentication, and key exchange of the communication partner device are performed, a state in which the communication partner device transmits a signal after the initial setting, security authentication, and key exchange of the communication partner device are completed, and a state in which signal transmission with the communication partner device is stopped. The communication device according to claim 1.

3. The signal transmission state includes at least a state in which at least one of the communication partner device and the communication device is powered on, or at least one of the communication partner device and the communication device is reset, a state in which initial setting, security authentication, and key exchange of the communication partner device are performed, a state in which the communication partner device transmits a signal after the initial setting, security authentication, and key exchange of the communication partner device are completed, and a state in which signal transmission with the communication partner device is stopped. The communication device according to claim 1.

4. The communication control unit selects one from a plurality of signal ratio patterns representing types of signal ratios in the first direction and the second direction according to the signal transmission state, The communication unit switches between signal transmission in the first direction and signal transmission in the second direction by time-division based on the signal ratio pattern selected by the communication control unit. The communication device according to any one of claims 1 to 3.

5. A storage unit that stores the plurality of signal ratio patterns, The communication control unit selects one from the plurality of signal ratio patterns stored in the storage unit according to the signal transmission state, The communication device according to claim 4, wherein the communication unit transmits a signal indicating the signal ratio pattern selected by the communication control unit to the communication partner device.

6. The communication unit transmits and receives signals having a predetermined frame structure, The frame structure includes information indicating whether to allow a change in a count value that defines a timing for changing signal ratios in the second direction and the first direction, information indicating the count value, the signal ratio pattern being selected, the signal ratio pattern to be selected next, and information indicating whether to allow a change in the signal ratio. The communication device according to claim 4.

7. The frame structure is included in OAM (Operation Administration and Maintenance). The communication device according to claim 6.

8. When the communication control unit changes the signal ratios in the first direction and the second direction, after a period that is n times (n is an integer of 2 or more) the fixed period has elapsed, the communication control unit changes the signal ratios in the first direction and the second direction. The communication device according to any one of claims 1 to 7.

9. The communication control unit changes the signal ratios in the first direction and the second direction only when it receives a response from the communication partner device approving a change in the signal ratio pattern within a period that is n times the fixed period. The communication device according to claim 8.

10. The communication unit transmits and receives signals having a frame structure including one or more containers in which the signals transmitted and received are stored every fixed period, The communication control unit adjusts the number of the containers according to the signal transmission state. The communication device according to any one of claims 1 to 9.

11. The communication device according to claim 10, wherein the frame structure includes a synchronization signal, at least one of the containers transmitted and received within the fixed period, and a parity signal.

12. The communication control unit makes the signal ratio in the first direction and the signal ratio in the second direction 1:1 in at least one of the cases where the communication device and the communication partner device perform security authentication and key exchange, when the communication device performs initial setting, and when the communication partner device performs initial setting. The communication device according to any one of claims 1 to 11.

13. The signal ratio according to any one of claims 1 to 12 is a ratio of signal amounts or a usage ratio of signals. The communication device according to any one of claims 1 to 12.

14. The communication unit can transmit the captured video signal. The communication control unit makes the signal ratio in the second direction during the period of receiving the video signal from the communication partner device higher than the signal ratio in the first direction. The communication device according to any one of claims 1 to 13.

15. The communication unit receives the video signal transmitted from the communication partner device in units of video frames. The communication control unit makes the signal ratio in the second direction during the period of receiving the video signal within one video frame higher than the signal ratio in the second direction during the vertical blanking period after receiving the video signal within one video frame. The communication device according to claim 14.

16. The communication unit transmits the video signal to the communication partner device in units of video frames. The communication control unit stops the signal transmission in the first direction and the second direction during the vertical blanking period after transmitting the video signal within one video frame. The communication device according to claim 14.

17. The communication unit can transmit a video signal to be displayed on the display unit of the communication partner device or to be processed by the processing unit of the communication partner device. The communication control unit makes the signal ratio in the second direction during a period in which a video signal is transmitted to the communication partner device higher than the signal ratio in the first direction. The communication device according to any one of claims 1 to 16.

18. The communication partner device is a slave device that performs signal transmission with the communication unit based on an instruction from the communication control unit. The communication device according to any one of claims 1 to 17.

19. The communication partner device is a master device that performs signal transmission with the communication unit based on an instruction from the communication control unit. The communication device according to any one of claims 1 to 17.

20. A master device, A slave device that performs signal transmission with the master device according to an instruction from the master device, and The master device and the slave device change the signal ratio in the first direction from the master device to the slave device and the signal ratio in the second direction from the slave device to the master device according to the signal transmission state between the master device and the slave device, using a predetermined fixed period as a unit, time-divide the fixed period, and switch between the signal transmission in the first direction and the signal transmission in the second direction, and adjust the signal ratios in the first direction and the second direction for each fixed period. A communication system.

21. Performs signal transmission between the master device and the slave device according to an instruction from the master device, The master device and the slave device change the signal ratio in the first direction from the master device to the slave device and the signal ratio in the second direction from the slave device to the master device according to the signal transmission state between the master device and the slave device, using a predetermined fixed period as a unit, time-divide the fixed period, and switch between the signal transmission in the first direction and the signal transmission in the second direction, A communication method for adjusting signal ratios in the first direction and the second direction for each of the fixed periods.

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