Communication system, communication device, program, and communication method

Abstract

To provide a communication system, a communication device, a program, and a communication method capable of increasing certainty of wireless data transmission.SOLUTION: A communication system 100 includes a base station 2 and an in-vehicle device 1. The in-vehicle device 1 includes a reference signal acquisition unit 103 that acquires a reference signal from the base station 2, a propagation path state determination unit 104 that determines a propagation path state on the basis of the reference signal, a CQI report transmission processing unit 116 that generates a CQI report regarding the propagation path state on the basis of the determined propagation path state and transmits the CQI report to the base station 2, and a reception processing unit 102 that receives data transmitted in a communication mode corresponding to the propagation path state indicated by the CQI report from the base station 2. When downloading predetermined data via the base station 2, the CQI report transmission processing unit 116 generates a CQI report indicating a propagation path state that is worse than an actual propagation path state and transmits the generated CQI report to the base station 2.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a communication system, a communication device, a program, and a communication method. [Background technology]

[0002] In recent years, technologies have been developed to improve the quality of communication between terminals using voice, images, etc. during calls and data transmission for driving assistance, remote control, and automatic driving of mobile objects such as automobiles. For example, Patent Document 1 describes a technology in which, since the estimation accuracy of channel information between wireless communication terminals decreases, a modulation mode consisting of a modulation method and a coding rate used for data transmission from one wireless communication terminal to another wireless communication terminal is changed to one with a lower transmission bit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5520756 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, in remote control of a moving object such as an automobile, it is important from the viewpoint of safety and practicality that a control signal, etc. transmitted from a server device, etc. via a base station is delivered to the moving object reliably. Although Patent Document 1 claims that it is possible to reduce the possibility of packet errors occurring due to interference signals, there is still room for improvement in terms of more reliable data transmission between communication devices.

[0005] An object of the present invention is to provide a communication system, a communication device, a program, and a communication method that can increase the reliability of wireless data transmission. [Means for solving the problem]

[0006] (1) A communication system includes a first communication device and a second communication device which wirelessly transmit data to each other, wherein the first communication device includes a reference signal transmitting unit which transmits to the second communication device a reference signal for determining a propagation path state, which is the state of a propagation path of data between the first communication device and the second communication device, and the second communication device includes a reference signal acquiring unit which acquires the reference signal from the first communication device, a determining unit which determines the propagation path state based on the acquired reference signal, a propagation path information transmitting unit which generates propagation path information regarding the propagation path state based on the propagation path state determined by the determining unit and transmits the propagation path information to the first communication device, and a receiving processing unit which receives data transmitted from the first communication device in a communication mode corresponding to the propagation path state indicated by the propagation path information, wherein when downloading specified data via the first communication device, the propagation path information transmitting unit generates propagation path information indicating a propagation path state which is lower than the actual propagation path state determined by the determining unit, and transmits the propagation path information to the first communication device.

[0007] (2) In the communication system described in (1), the second communication device is an in-vehicle device mounted on a moving body capable of operating in a plurality of operating modes, and further includes a operating mode determination unit that determines whether the operating mode of the moving body is set to a predetermined operating mode, and when the operating mode determination unit determines that the operating mode of the moving body is set to the predetermined operating mode, the propagation path information transmission unit determines that this corresponds to a case where predetermined data is downloaded via the first communication device.

[0008] (3) In the communication system described in (1) or (2), the second communication device is an in-vehicle device mounted on a moving body, and further includes a movement information acquisition unit that acquires movement information including at least a movement speed of the moving body, and the propagation path information transmission unit generates the propagation path information by taking into account the movement information.

[0009] (4) In a communication system described in any one of (1) to (3), the second communication device is an in-vehicle device mounted on a moving body, and further includes a weather information acquisition unit that acquires weather information about the surroundings of the moving body, and the propagation path information transmission unit generates the propagation path information by taking into account the weather information.

[0010] (5) In a communication system described in any one of (1) to (4), the second communication device is an in-vehicle device mounted on a moving body, and further includes a route information acquisition unit that acquires route information regarding a route along which the moving body is scheduled to move, and the propagation path information transmission unit generates the propagation path information by taking into account the route information.

[0011] (6) A communication device is a communication device that wirelessly transmits data between a specific communication device and the specific communication device, and includes a reference signal acquisition unit that acquires a reference signal for determining a propagation path state, which is the state of a propagation path of data to the specific communication device, a judgment unit that judges the propagation path state based on the acquired reference signal, a propagation path information transmission unit that generates propagation path information regarding the propagation path state based on the propagation path state judged by the judgment unit and transmits the propagation path information to the specific communication device, and a reception processing unit that receives data transmitted from the specific communication device in a communication mode corresponding to the propagation path state indicated by the propagation path information, and when downloading specified data via the specific communication device, the propagation path information transmission unit generates the propagation path information indicating the propagation path state that is lower than the actual propagation path state judged by the judgment unit, and transmits the propagation path information to the specific communication device.

[0012] (7) The program causes a computer included in a communication device that wirelessly transmits data between the specific communication device to execute an acquisition step of acquiring a reference signal for determining a propagation path state, which is the state of a propagation path of data to the specific communication device; a determination step of determining the propagation path state based on the acquired reference signal; a propagation path information transmission step of generating propagation path information regarding the propagation path state based on the propagation path state determined in the determination step and transmitting the propagation path information to the specific communication device; and a receiving step of receiving data transmitted from the specific communication device in a communication mode corresponding to the propagation path state indicated by the propagation path information. In the propagation path information transmission step, when specific data is downloaded via the specific communication device, a process is executed to generate propagation path information indicating a propagation path state that is lower than the actual propagation path state determined in the determination step, and transmit the propagation path information to the specific communication device.

[0013] (8) A communication method is a communication method executed by a communication device that wirelessly transmits data between the specific communication device, and includes an acquisition step of acquiring a reference signal for determining a propagation path state, which is the state of a propagation path of data to the specific communication device, a determination step of determining the propagation path state based on the acquired reference signal, a propagation path information transmission step of generating propagation path information regarding the propagation path state based on the propagation path state determined in the determination step and transmitting the propagation path information to the specific communication device, and a receiving step of receiving data transmitted from the specific communication device in a communication mode corresponding to the propagation path state indicated by the propagation path information, wherein in the propagation path information transmission step, when downloading specified data via the specific communication device, a process is executed to generate propagation path information indicating a propagation path state that is lower than the actual propagation path state determined in the determination step, and transmit the propagation path information to the specific communication device. Effect of the Invention

[0014] According to the present invention, it is possible to increase the reliability of wireless data transmission. [Brief description of the drawings]

[0015] [Figure 1] 1 is a schematic diagram showing a communication system according to an embodiment of the present invention and a mobile object using the communication system moving on a road. [Diagram 2] 2 is a block diagram showing the configuration of hardware and functional blocks of a base station of a communication system according to one embodiment of the present invention. FIG. [Diagram 3] FIG. 13 is a diagram illustrating an example of a CQI table. [Figure 4] 1 is a block diagram showing a configuration of hardware and functional blocks of an in-vehicle device of a communication system according to an embodiment of the present invention; [Diagram 5] 4 is a sequence diagram showing an example of a flow until downlink transmission data is transmitted from a base station to an in-vehicle device in the communication system according to the embodiment of the present invention. FIG. [Figure 6] 5 is a flowchart showing an example of a safety communication process executed by an in-vehicle device of the communication system according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] A communication system 100 according to an embodiment of the present invention will be described below. Note that the present invention is not limited to the following embodiment. Also, each drawing referred to in the following description merely shows a schematic shape, size, and positional relationship to the extent that the contents of the present disclosure can be understood. In other words, the present invention is not limited to only the shape, size, and positional relationship exemplified in each drawing.

[0017] An overall configuration of a communication system 100 according to a first embodiment will be described with reference to Fig. 1. Fig. 1 is a schematic diagram showing the communication system 100 and a mobile object 4 using the communication system 100 moving on a road 5.

[0018] The communication system 100 is a system for performing wireless communication between an in-vehicle device (communication device) 1 and a base station 2. The communication system 100 includes the in-vehicle device 1 and a server device 3 communicably connected to the base station 2 via a communication network NW. In this embodiment, the communication system 100 will be described using an example of data transmission between the in-vehicle device 1 mounted on a moving body 4, which is a vehicle, and the base station 2. Note that FIG. 1 shows a state in which the moving body 4 mounting the in-vehicle device 1 is moving in a moving direction X while communicating wirelessly with the base station 2. That is, the in-vehicle device 1 wirelessly communicates with the base station 2 while moving in the moving direction X due to the movement of the moving body 4. Note that the moving body 4 may communicate with the base station 2 while not moving and while stopped.

[0019] The in-vehicle device 1 has a function of using, for example, car navigation, an ITS (Intelligent Transportation System), and V2X communication. The in-vehicle device 1 wirelessly transmits data to a base station 2 and receives data transmitted from the base station 2. The type and attribute of data transmitted between the in-vehicle device 1 and the base station 2 are not particularly limited. For example, the type of data to be transmitted may be data indicating the surroundings of the mobile object 4 including the road 5, data for controlling the driving of the mobile object 4, or data indicating information about the mobile object 4. The attribute of the data to be transmitted may be image data, point cloud data, voice data, text data, or a signal.

[0020] The moving body 4 on which the in-vehicle device 1 of the present embodiment is mounted can be driven in a plurality of driving modes. Examples of driving modes set for the moving body 4 include a normal driving mode and an automatic driving mode. The normal driving mode is a mode in which the driving of the moving body 4 is controlled by the driver's operation. The automatic driving mode includes, for example, a remote control mode and an autonomous driving mode. The remote control mode is a mode in which the driving of the moving body 4 is controlled by a control signal transmitted from an external device such as a server device 3 via a base station 2 or the like. The autonomous driving mode is a mode in which the moving body 4 itself controls the driving of the moving body 4 based on information on the surrounding environment, etc., and can travel by itself. The driving mode is not limited to the above, and may include a mode in which the driver's operation is assisted.

[0021] The server device 3 generates data for controlling or assisting the driving of the in-vehicle device 1 in response to data received from the in-vehicle device 1 via the base station 2, and performs processing to transmit the data to the in-vehicle device 1 via the base station 2. The server device 3 acquires data from the in-vehicle device 1 via the base station 2 and the communication network NW, generates various data to be returned to the in-vehicle device 1 in response to the data, and transmits the data to the in-vehicle device 1 via the base station 2 and the communication network NW. For example, the server device 3 may generate a control signal for remotely controlling the moving object 4 based on image data transmitted from the in-vehicle device 1, and transmit the control signal to the in-vehicle device 1 via the base station 2 and the communication network NW.

[0022] The base station 2 transmits data to and from an in-vehicle device 1 mounted on a moving object 4 traveling within an area where wireless communication is possible (hereinafter, referred to as a communication area), and also transmits data to and from a server device 3 via a communication network NW. The base station 2 receives image data indicating the surrounding conditions of the moving object 4, for example, from the in-vehicle device 1, and transmits the received image data via the communication network NW to the server device 3. The base station 2 then receives a control signal for the moving object 4 generated based on the image data from the server device 3, and transmits the received control signal wirelessly to the in-vehicle device 1.

[0023] Here, in communication between the in-vehicle device 1 mounted on a moving body 4 such as a traveling vehicle and the base station 2, the position of the in-vehicle device 1 changes, so the state of the data propagation path between the in-vehicle device 1 and the base station 2 (hereinafter referred to as the propagation path state) changes in real time. Even if the moving body 4 does not move, the state of the data propagation path between the in-vehicle device 1 and the base station 2 changes in real time due to an increase or decrease in the number of other moving bodies in the vicinity. For example, the propagation path state changes due to a change in the distance from the in-vehicle device 1 to the base station 2, radio wave interference due to the presence of other communication devices communicating with the base station 2, the presence or absence of obstacles between the in-vehicle device 1 and the base station 2, etc. For this reason, there is a risk that communication between the in-vehicle device 1 and the base station 2 will be interrupted or communication quality will be degraded. In remote control of the moving body 4 such as a vehicle, it is important from the standpoint of safety and practicality that the control signal of the moving body 4 transmitted from the base station 2 is reliably delivered to the in-vehicle device 1. In this embodiment, in substantially real-time data transmission between communication devices realized by wireless communication systems such as LTE and 5G, the reliability of data transmission between the communication devices can be increased by the secure communication processing described below.

[0024] Next, a description will be given of the functional configuration of the base station 2. Fig. 2 is a block diagram illustrating an example of the configuration of hardware and functional blocks of the base station 2.

[0025] As shown in FIG. 2, the base station 2 includes a processing unit 20, a communication I / F unit 21, a wireless communication unit 22, and a storage unit 23.

[0026] The communication I / F unit 21 is an interface for the base station 2 to communicate via the communication network NW. The base station 2 is connected to the server device 3 via the communication I / F unit 21 so as to be able to communicate with each other.

[0027] The wireless communication unit 22 executes a process for the base station 2 to wirelessly communicate with surrounding wireless terminal devices. The wireless communication unit 22 includes an antenna for transmitting and receiving radio waves. The wireless communication unit 22 performs wireless communication with a mobile object 4 that moves within the communication area of ​​the base station 2.

[0028] The storage unit 23 is a storage area for various programs for causing the hardware group to function as the base station 2, various data, etc., and can be configured with a ROM, a RAM, a flash memory, a solid-state drive (SSD), a hard disk drive (HDD), etc. Specifically, the storage unit 23 stores a program for causing the processing unit 20 to execute each function of this embodiment, a control program for the base station 2, various parameters, etc.

[0029] The processing unit 20 is, for example, a processor, and is a central part of a computer that performs operations such as calculations and control necessary for the operation of the base station 2, and performs various calculations and processes. The processor is a central processing unit (CPU), a micro processing unit (MPU), a system on a chip (SoC), a digital signal processor (DSP), a graphics processing unit (GPU), an application specific integrated circuit (ASIC), a programmable logic device (PLD), or a field-programmable gate array (FPGA). Alternatively, the processor is a combination of a plurality of these. The processor may also be a combination of these with a hardware accelerator. The processor controls each part to realize various functions of the base station 2 based on programs such as firmware, system software, and application software stored in a ROM (not shown) or an auxiliary storage device (not shown). Note that a part or all of the programs may be incorporated in the circuit of the processor.

[0030] The processing unit 20 includes a transmission processing unit 201 , a reception processing unit 202 , a reference signal transmitting unit (standard signal transmitting unit) 203 , a CQI (Channel Quality Indicator) report acquiring unit 204 , and a communication mode selecting unit 205 .

[0031] The transmission processing unit 201 executes a process of transmitting data via the communication I / F unit 21 and the wireless communication unit 22. The transmission processing unit 201 receives data from the server device 3 via the communication I / F unit 21, and controls the wireless communication unit 22 to modulate and transmit the data received from the server device 3 to the in-vehicle device 1.

[0032] The reception processing unit 202 executes a process of receiving data from the server device 3 and the in-vehicle device 1 via the communication I / F unit 21 and the wireless communication unit 22 .

[0033] The reference signal transmission unit 203 transmits a reference signal to the in-vehicle device 1. The reference signal is a reference signal for determining a propagation path state between the base station 2 and the in-vehicle device 1. For example, when the base station 2 and the in-vehicle device 1 start communication, the reference signal transmission unit 203 may transmit a reference signal for determining a propagation path state when transmitting data from the base station 2 to the in-vehicle device 1.

[0034] The CQI report acquisition unit 204 executes a process of acquiring propagation path information regarding the state of the propagation path between the base station 2 and the vehicle-mounted device 1. In this embodiment, the CQI report acquisition unit 204 acquires a CQI report transmitted from the vehicle-mounted device 1 as the propagation path information. The CQI is an index indicating the state of the propagation path between the base station 2 and the vehicle-mounted device 1.

[0035] The communication mode selection unit 205 selects a communication mode for transmitting data from the base station 2 to the vehicle-mounted device 1 based on the CQI report acquired by the CQI report acquisition unit 204, and allocates resources for transmitting the data to the vehicle-mounted device 1. The communication mode is determined by the CQI index, and is a mode defined by a modulation method, a coding rate, and frequency utilization efficiency. The communication mode selection unit 205 may select a communication mode corresponding to the acquired CQI report by referring to a CQI table as shown in FIG. 3, for example. In the example shown in FIG. 3, QPSK (Quadrature Phase Shift Keying), 16QAM (Quadrature Amplitude Modulation), 64QAM, and 256QAM are shown as modulation methods, and coding rates of error correction codes ranging from 78×1024 to 948×1024 are shown. For example, when the CQI value (CQIindex in FIG. 3) indicated by the CQI report is 9, the communication mode selection unit 205 selects a communication mode in which the modulation method is 64QAM and the coding rate is 666×1024. The communication mode selection unit 205 selects a communication mode in which the CQI value is higher and the modulation order and coding rate are higher when the propagation path state is better, i.e., the propagation path state is higher, and selects a communication mode in which the CQI value is lower and the modulation order and coding rate are lower when the propagation path state is worse, i.e., the propagation path state is lower. That is, the communication mode selection unit 205 selects a communication mode in which the communication speed is faster but the noise resistance is lower when the propagation path state is higher, and selects a communication mode in which the communication speed is slower but the noise resistance is higher when the propagation path state is lower. Noise resistance is the resistance of data transmission to the influence of noise.

[0036] Next, a description will be given of the functional configuration of the in-vehicle device 1. Fig. 4 is a block diagram illustrating the configuration of the hardware and functional blocks of the in-vehicle device 1.

[0037] The in-vehicle device 1 includes a sensor unit 11, a wireless communication unit 12, a communication I / F 13, a storage unit 14, and a processing unit 10.

[0038] The sensor unit 11 is a device that detects the movement information of the moving body 4 and the information of the surroundings of the moving body 4. The sensor unit 11 may be configured to include various sensors that acquire the movement information of the moving body 4, such as a vehicle speed sensor, an acceleration sensor, and an angular velocity sensor, a camera, a radar, a LiDAR (Light Detection And Ranging), and the like. Examples of the movement information of the moving body 4 include the traveling speed and traveling direction of the moving body 4. The camera detects the surrounding information of the object by capturing an image such as a still image or a video of the surroundings of the moving body 4. The radar and LiDAR detect the distance, direction, relative speed, and the like of the object existing around the moving body 4 based on the transmission wave transmitted to the surroundings of the moving body 4 and the reflected received wave. The LiDAR irradiates a laser light around the moving body 4 and detects the surrounding objects as point cloud data. The LiDAR can detect the position, shape, and the like of the surrounding objects with high accuracy. The sensor unit 11 transmits the detected movement information, image data, and point cloud data of the moving body 4 to the processing unit 10.

[0039] The sensor unit 11 may have a function of detecting the movement of a wiper. If the wiper is moving, it means that it is raining or snowing, and the communication environment may be worse than in a sunny day. For example, when the wiper is moving, the CQIindex may be changed to a lower order than normal, thereby improving the security of communication. Also, for example, since it can be predicted that the faster the wiper moves, the heavier the amount of rainfall or snowfall, the security of communication may be improved by changing the CQIindex to a lower order than normal.

[0040] The sensor unit 11 may also be configured to have a function of cooperating with a car navigation system, i.e., a route information generating unit that generates a route (route information) from the current position to the destination. In this configuration, the sensor unit 11 receives route information on the planned route along which the mobile object 4 is to move from the car navigation system. For example, if there is a place on the route along which the mobile object 4 is to move where the communication environment is degraded, the CQIindex can be changed to a lower order than normal when the mobile object 4 arrives at or passes through that place, thereby improving the security of communication.

[0041] The wireless communication unit 12 executes a process for the in-vehicle device 1 to perform wireless communication with the base station 2, etc. The wireless communication unit 12 includes an antenna for transmitting and receiving radio waves. The wireless communication unit 12 transmits data generated by the processing unit 10 to the base station 2.

[0042] The communication I / F unit 13 is an interface for the in-vehicle device 1 to communicate via the communication network NW. The in-vehicle device 1 is connected to an ECU (Electronic Control Unit) 41 of the moving object 4 and the like via the communication I / F unit 13 so as to be able to communicate with each other.

[0043] The storage unit 14 is a storage area for various programs and various data for making the hardware group function as the in-vehicle device 1, and can be configured with a ROM, a RAM, a flash memory, a solid-state drive (SSD), a hard disk drive (HDD), etc. Specifically, the storage unit 14 stores a program for making the processing unit 10 execute each function of the present embodiment, a control program for the in-vehicle device 1, various parameters, identification information such as the IP address and MAC address of the in-vehicle device 1, a table indicating the relationship between the type of data transmitted from the in-vehicle device 1 and the type of data transmitted from the base station 2 in response to the data, a CQI table, etc.

[0044] The processing unit 10 is, for example, a processor, and is a central part of a computer that performs processing such as calculations and control necessary for the operation of the in-vehicle device 1, and performs various calculations and processing. The processor is a central processing unit (CPU), a micro processing unit (MPU), a system on a chip (SoC), a digital signal processor (DSP), a graphics processing unit (GPU), an application specific integrated circuit (ASIC), a programmable logic device (PLD), or a field-programmable gate array (FPGA). Alternatively, the processor is a combination of a plurality of these. The processor may also be a combination of these with a hardware accelerator or the like. The processor controls each part to realize various functions of the in-vehicle device 1 based on programs such as firmware, system software, and application software stored in a ROM (not shown) or an auxiliary storage device (not shown). Note that a part or all of the programs may be incorporated in the circuit of the processor.

[0045] As shown in FIG. 4, the processing unit 10 includes a transmission processing unit 101, a reception processing unit 102, a reference signal acquisition unit (standard signal acquisition unit) 103, a propagation path condition determination unit (determination unit) 104, and a CQI processing unit 110.

[0046] The transmission processing unit 101 executes a process of transmitting data to a wireless communication device such as the base station 2 via the wireless communication unit 12. For example, the transmission processing unit 101 controls the wireless communication unit 12 to modulate image data, point cloud data, etc., indicating the situation around the mobile object 4 detected by the sensor unit 11, and transmits the data to the base station 2. In addition, for example, the transmission processing unit 101 transmits a control signal received from the base station 2 to the ECU 41 via the communication I / F unit 13.

[0047] The reception processing unit 102 executes a process of receiving data from a wireless communication device such as the base station 2 via the wireless communication unit 12. For example, the reception processing unit 102 controls the wireless communication unit 12 to demodulate and receive data such as a control signal transmitted from the base station 2 in a communication mode corresponding to the propagation path information indicated by the CQI report.

[0048] The reference signal acquisition unit 103 executes a process of acquiring a reference signal from the base station 2 via the wireless communication unit 12 .

[0049] The propagation path state determination unit 104 executes a process of determining the propagation path state based on a reference signal received from the base station 2. The propagation path state determination unit 104 may, for example, detect information of the reference signal received from the base station 2 and compare the detected information with information of the reference signal of the base station 2 stored in advance in the storage unit 14 to determine the propagation path state.

[0050] The CQI processing unit 110 has a propagation path condition acquisition unit 111, a movement information acquisition unit 112, a weather information acquisition unit 113, a route information acquisition unit 114, a communication mode determination unit (operating method determination unit) 115, and a CQI report transmission processing unit (propagation path information transmission unit) 116.

[0051] The propagation path condition acquisition unit 111 acquires propagation path information indicating the propagation path condition determined by the propagation path condition determination unit 104 .

[0052] The movement information acquisition unit 112 acquires movement information including at least the movement speed and movement direction of the moving object 4 from the sensor unit 11 .

[0053] The weather information acquisition unit 113 executes a process of acquiring weather information around the mobile object 4. The CQI report transmission processing unit (propagation path information transmission unit) 116 generates a CQI report taking into account the weather information. For example, the weather information acquisition unit 113 may acquire weather information by determining the weather around the mobile object 4 based on information related to the movement of the wipers of the mobile object 4 detected by the sensor unit 11. For example, the weather information acquisition unit 113 may determine that the weather is sunny, cloudy, or the like when the wipers are not moving, and may determine that the weather is rainfall, snowfall, or the like when the wipers are moving, and may determine that the amount of rainfall or snowfall is greater the faster the wipers move. The weather information acquisition unit 113 may determine the weather around the mobile object 4 based on temperature information and humidity information around the mobile object 4.

[0054] The route information acquisition unit 114 executes a process of acquiring route information regarding a planned travel route of the mobile object 4 from the car navigation system via the sensor unit 11. The CQI report transmission processing unit (propagation path information transmission unit) 116 generates a CQI report by taking into account the route information.

[0055] The communication mode determination unit 115 determines the operation method of the mobile object 4, and determines whether to set the communication mode between the base station 2 and the in-vehicle device 1 to the normal communication mode or the safe communication mode based on the determined operation method. The normal communication mode is a communication mode with a communication speed and noise resistance according to the propagation path state determined by the propagation path state determination unit 104. The safe communication mode is a communication mode with a lower communication speed and higher noise resistance than the normal communication mode. For example, when the communication mode determination unit 115 determines that the operation method of the mobile object 4 is the normal operation method, it determines that the communication mode is to be set to the normal communication mode. Also, when the communication mode determination unit 115 determines that the operation method of the mobile object 4 is the remote control method, it determines that the communication mode is to be set to the safe communication mode. The safe communication mode is set when downloading predetermined data via the base station 2. The predetermined data is data that is required to be reliably acquired from the base station 2 by the in-vehicle device 1 set to the remote control method from the viewpoint of safety, etc., and has a relatively small capacity that can be transmitted with low delay even at a relatively low speed, such as a control signal for the mobile object 4. Data with a relatively small volume is data that is preferable not to be retransmitted, such as, but not limited to, commands transmitted from a base station to a mobile unit 4 during autonomous driving (e.g., commands to operate the steering wheel, brake, etc.).

[0056] The CQI report transmission processing unit 116 executes processing to generate a CQI report to be transmitted to the base station 2 and transmit the CQI report to the base station 2. When the communication mode determination unit 115 determines that the communication mode should be set to the normal communication mode, the CQI report transmission processing unit 116 generates a CQI report indicating the propagation path state determined by the propagation path state determination unit 104 and transmits the CQI report to the base station 2.

[0057] When the communication mode determination unit 115 determines that the communication mode is set to the safe communication mode, the CQI report transmission processing unit 116 generates a CQI report indicating a propagation path state corresponding to the safe communication mode and transmits it to the base station 2. That is, when downloading predetermined data via the base station 2, the CQI report transmission processing unit 116 generates a CQI report indicating a propagation path state lower than the actual propagation path state determined by the propagation path state determination unit 104 and transmits it to the base station 2. When the communication mode determination unit 115 determines that the operation method of the mobile object 4 is set to a predetermined operation method such as a remote control method, the CQI report transmission processing unit 116 determines that this corresponds to a case where predetermined data is downloaded via the base station 2. The base station 2 that receives this CQI report allocates resources for a communication mode that has a slower communication speed and higher noise resistance than the communication mode corresponding to the actual propagation path state in order to transmit data from the base station 2 to the vehicle-mounted device 1. This allows the control signal of the mobile object 4 and the like to be transmitted reliably from the base station 2 to the vehicle-mounted device 1.

[0058] Also, for example, when it is determined that the safe communication mode is to be set, the CQI report transmission processing unit 116 may generate a CQI report corresponding to the specified safe communication mode by taking into account the movement information of the mobile object 4 acquired by the movement information acquisition unit 112, and transmit the CQI report to the base station 2. Here, the communication quality tends to deteriorate due to Doppler shift as the moving speed of the mobile object 4 increases. In consideration of this tendency to deteriorate due to Doppler shift, the CQI report transmission processing unit 116 may generate a CQI report indicating a lower propagation path state as the moving speed of the mobile object 4 increases. Also, for example, the CQI report transmission processing unit 116 may generate a CQI report indicating a propagation path state corresponding to a communication mode with the highest noise resistance that can transmit all data to the base station 2 for the in-vehicle device 1 moving at this moving speed, based on the moving speed of the mobile object 4, and transmit the CQI report to the base station 2. This can further increase the reliability of communication within the time limit.

[0059] Furthermore, for example, when it is determined to set the safe communication mode, the CQI report transmission processor 116 may generate a CQI report corresponding to the specified safe communication mode taking into account meteorological information, and transmit the CQI report to the base station 2. Considering that the communication environment may be worse during rain or snow compared to sunny days as described above, when the meteorological information indicates rain or snow, the CQI report transmission processor 116 may generate a CQI report indicating a worse propagation path condition than during sunny days.

[0060] Furthermore, for example, when it is determined to set the safe communication mode, the CQI report transmission processor 116 may generate a CQI report corresponding to the specified safe communication mode by taking into account route information of the mobile unit 4, and transmit the CQI report to the base station 2. Specifically, when there is a place where the communication environment deteriorates on the movement route of the mobile unit 4, the CQI report transmission processor 116 may generate a CQI report indicating even worse propagation path conditions when the mobile unit 4 arrives at or passes through that place.

[0061] Next, a process flow for transmitting data from the base station 2 to the vehicle-mounted device 1 will be described with reference to Fig. 5 and Fig. 6. In the following description, data transmitted from the base station 2 to the vehicle-mounted device 1 will also be referred to as downlink transmission data.

[0062] First, a description will be given of the flow of processing between the base station 2 and the vehicle-mounted device 1 until downlink transmission data is transmitted from the base station 2 to the vehicle-mounted device 1. Fig. 5 is a sequence diagram showing an example of the flow until downlink transmission data is transmitted from the base station 2 to the vehicle-mounted device 1.

[0063] As shown in FIG. 5, a reference signal is transmitted from the base station 2 to the vehicle-mounted device 1 in step S1.

[0064] In step S2, the vehicle-mounted device 1 receives the reference signal transmitted in step S1, and determines the propagation path state based on the received reference signal.

[0065] In step S3, the in-vehicle device 1 generates a CQI report based on the propagation path condition determined in step S2.

[0066] In step S4, the vehicle-mounted device 1 transmits the CQI report generated in step S3 to the base station 2.

[0067] In step S5, the base station 2 selects a communication mode for transmitting data from the base station 2 to the vehicle-mounted device 1 based on the received CQI report.

[0068] In step S6, the base station 2 allocates resources for transmitting data to the vehicle-mounted device 1 in accordance with the communication mode selected in step S5.

[0069] In step S7, the base station 2 transmits the downlink transmission data to the vehicle-mounted device 1 in the communication mode selected in step S5.

[0070] Next, an example of the safety communication process executed by the processing unit 10 of the in-vehicle device 1 mounted on the moving object 4 will be described with reference to Fig. 6. Fig. 6 is a flowchart showing an example of the safety communication process executed by the in-vehicle device 1.

[0071] As shown in FIG. 6, in step S11, the reference signal acquisition unit 103 of the processing unit 10 acquires a reference signal from the base station 2 via the wireless communication unit 12 for determining the state of the propagation path used for transmitting data from the base station 2 to the vehicle-mounted device 1.

[0072] In step S12, the propagation path condition determining unit 104 determines the propagation path condition between the base station 2 and the vehicle-mounted device 1 based on the reference signal acquired in step S11.

[0073] In step S13, the CQI report transmission processing unit 116 judges whether or not the predetermined data is to be downloaded via the base station 2. For example, when the communication mode judgment unit 115 judges that the operation mode of the mobile unit 4 is set to a predetermined operation mode, the CQI report transmission processing unit 116 judges that the predetermined data is to be downloaded via the base station 2. When the CQI report transmission processing unit 116 judges that the predetermined data is not to be downloaded via the base station 2 (step S13; NO), the CQI report transmission processing unit 116 shifts the process to step S14. Then, in step S14, the CQI report transmission processing unit 116 generates a CQI report corresponding to the communication speed and the noise-resistant communication mode according to the propagation path state judged in step S12, and shifts the process to step S19. On the other hand, when the CQI report transmission processing unit 116 judges that the predetermined data is to be downloaded via the base station 2 (step S13; YES), the CQI report transmission processing unit 116 shifts the process to step S15. In the example shown in FIG. 6, the predetermined data may be, for example, a control signal for remotely controlling the moving object 4, and the predetermined operation method may be, for example, a remote control method.

[0074] In step S15, the movement information acquisition unit 112 acquires movement information including the movement speed and movement direction of the moving object 4.

[0075] In step S16, the CQI report transmission processor 116 identifies a safe communication mode that is a communication mode with a lower communication speed and higher noise resistance than the communication mode with the communication speed and noise resistance according to the propagation path state determined in step S12. For example, the CQI report transmission processor 116 may identify the safe communication mode by taking into account the movement information acquired in step S15. The identified safe communication mode may be a communication mode with the highest noise resistance and capable of transmitting all downlink transmission data to the base station 2 from the in-vehicle device 1 moving at the movement speed acquired in step S15.

[0076] In step S17, the CQI report transmission processor 116 generates a CQI report corresponding to the secure communication mode identified in step S16.

[0077] In step S18, the CQI report transmission processor 116 transmits the CQI report generated in step S17 to the base station 2.

[0078] In step S19, the reception processing unit 102 acquires downlink transmission data from the base station 2 via the wireless communication unit 12. After that, the processing unit 10 ends the secure communication process.

[0079] According to the embodiment described above, the following effects are achieved.

[0080] The communication system 100 according to this embodiment includes a base station 2 and an in-vehicle device 1 that wirelessly transmit data to each other. The base station 2 includes a reference signal transmission unit 203 that transmits a reference signal to the in-vehicle device 1 for determining a propagation path state, which is the state of a propagation path of data between the base station 2 and the in-vehicle device 1. The in-vehicle device 1 includes a reference signal acquisition unit 103 that acquires a reference signal from the base station 2, a propagation path state determination unit 104 that determines the propagation path state based on the acquired reference signal, and a propagation path state determination unit 105 that determines the propagation path state based on the propagation path state determined by the propagation path state determination unit 104. the CQI report transmission processing unit 116 generating a CQI report regarding the propagation path state based on the propagation path state and transmitting the CQI report to the base station 2, and a reception processing unit 102 receiving data transmitted in a communication mode corresponding to the propagation path state indicated by the CQI report from the base station 2, when predetermined data is downloaded via the base station 2, the CQI report transmission processing unit 116 generates a CQI report indicating a propagation path state that is lower than the actual propagation path state determined by the determination unit, and transmits the CQI report to the base station 2.

[0081] As a result, for example, when the vehicle-mounted device 1 obtains downstream transmission data such as a control signal for the vehicle 4 from the base station 2 in remote control of the vehicle 4, the vehicle-mounted device 1 transmits to the base station 2 a determination result of the propagation path state, which is a determination result of the propagation path state corresponding to a communication mode with higher noise resistance than the communication mode corresponding to the actual propagation path state, instead of the actual propagation path state. That is, the vehicle-mounted device 1 notifies the base station 2 that the propagation path state is worse than the actual state, and the base station 2 that receives the result transmits data in a communication mode with higher noise resistance so that the data can be reliably delivered to the vehicle-mounted device 1 even in a bad propagation path state. Therefore, even when the vehicle-mounted device 1 communicates with the base station 2 while moving and the propagation path state changes, the vehicle-mounted device 1 can receive data from the base station 2 more reliably, and the reliability of communication between the base station 2 and the vehicle-mounted device 1 can be increased.

[0082] Furthermore, in the communication system 100 according to this embodiment, the in-vehicle device 1 is mounted on a moving body 4 that can be driven in a plurality of driving modes, and further includes a communication mode determination unit 115 that determines whether the driving mode of the moving body 4 is set to a predetermined driving mode, and when the communication mode determination unit 115 determines that the driving mode of the moving body 4 is set to a predetermined driving mode, the CQI report transmission processing unit 116 determines that this corresponds to a case where predetermined data is to be downloaded via the base station 2.

[0083] This makes it possible to increase the reliability of communication depending on the driving method of the moving object 4.

[0084] In addition, the in-vehicle device 1 according to this embodiment further includes a movement information acquisition unit 112 that is mounted on a moving body 4 and acquires movement information including at least the movement speed of the moving body 4, and the CQI report transmission processing unit 116 generates a CQI report taking into account the movement information.

[0085] As a result, the CQI report is generated taking into consideration the moving speed of the moving object 4, which is caused by the deterioration of communication quality, so that the reliability of data transmission between the base station 2 and the vehicle-mounted device 1 can be further improved.

[0086] In addition, the in-vehicle device 1 according to this embodiment is mounted on the moving body 4 and further includes a weather information acquisition unit 113 that acquires weather information about the surroundings of the moving body 4, and the CQI report transmission processing unit 116 generates a CQI report taking into account the weather information.

[0087] This allows the CQI report to be generated taking into account meteorological information caused by deterioration of communication quality, so that the reliability of data transmission between the base station 2 and the vehicle-mounted device 1 can be further improved.

[0088] Moreover, the in-vehicle device 1 according to this embodiment further includes a route information acquisition unit 114 that is mounted on the moving body 4 and acquires route information related to a route along which the moving body 4 is scheduled to travel, and the CQI report transmission processing unit 116 generates a CQI report taking into account the route information.

[0089] As a result, even if there is a place on the moving path of the mobile object 4 where the communication environment deteriorates, the CQI report can be generated taking into account the deterioration of the communication environment.

[0090] Moreover, the in-vehicle device 1 according to this embodiment is a communication device that wirelessly transmits data between the base station 2, and includes: a reference signal acquisition unit 103 that acquires a reference signal for determining a propagation path state, which is the state of a propagation path for data to the base station 2; a propagation path state determination unit 104 that determines the propagation path state based on the acquired reference signal; a CQI report transmission processing unit 116 that generates a CQI report on the propagation path state based on the propagation path state determined by the propagation path state determination unit 104 and transmits the CQI report to the base station 2; and a reception processing unit 102 that receives data transmitted in a communication mode corresponding to the propagation path state indicated by the CQI report from the base station 2. When downloading predetermined data via the base station 2, the CQI report transmission processing unit 116 generates a CQI report indicating a propagation path state that is lower than the actual propagation path state determined by the determination unit, and transmits the CQI report to the base station 2.

[0091] Furthermore, the program according to this embodiment causes a computer included in an in-vehicle device 1 that wirelessly transmits data to and from the base station 2 to execute the following steps: an acquisition step of acquiring a reference signal for determining a propagation path state, which is the state of the propagation path of data to and from the base station 2; a determination step of determining the propagation path state based on the acquired reference signal; a CQI report transmission step of generating a CQI report regarding the propagation path state based on the propagation path state determined in the determination step and transmitting the CQI report to the base station 2; and a receiving step of receiving data transmitted in a communication mode corresponding to the propagation path state indicated by the CQI report from the base station 2. In the CQI report transmission step, when predetermined data is downloaded via the base station 2, a process of generating a CQI report indicating a propagation path state that is lower than the actual propagation path state determined in the determination step and transmitting the CQI report to the base station 2 is executed.

[0092] Moreover, the communication method according to this embodiment is a communication method executed by an in-vehicle device 1 that wirelessly transmits data with a base station 2, and includes an acquisition step of acquiring a reference signal for determining a propagation path state, which is the state of a propagation path of data to the base station 2, a determination step of determining the propagation path state based on the acquired reference signal, a CQI report transmission step of generating a CQI report regarding the propagation path state based on the propagation path state determined in the determination step and transmitting the CQI report to the base station 2, and a receiving step of receiving data transmitted in a communication mode corresponding to the propagation path state indicated by the CQI report from the base station 2. In the CQI report transmission step, when predetermined data is downloaded via the base station 2, a process of generating a CQI report indicating a propagation path state that is lower than the actual propagation path state determined in the determination step and transmitting the CQI report to the base station 2 is executed.

[0093] Although the embodiment of the present invention has been described above, the present invention is not limited to the above-mentioned embodiment and can be modified as appropriate.

[0094] For example, when it is determined that the safe communication mode should be set, if there is no communication mode that has a slower communication speed and higher noise resistance than the communication mode according to the propagation path state determined by the communication mode determination unit 115, the CQI report transmission processing unit 116 may execute, for example, the following processes (a) to (d). (a) The base station 2 with which the in-vehicle device 1 communicates is switched, that is, the communication carrier is switched. (b) The wireless communication technique is switched from cellular communication with the base station 2 to another communication technique, for example, V2I communication, V2V communication, V2P communication, WiFi, Local 5G, Private LTE, or the like. (c) The directivity of the antenna of the wireless communication unit 12 is changed. (d) While there is no communication mode with a slower communication speed and higher noise resistance than the communication mode corresponding to the determined propagation path state, the operation mode of the moving body 4 is switched. For example, the operation mode is switched from a remote control mode in which the driving of the moving body 4 is controlled by a control signal from the base station 2 to an autonomous operation mode in which the moving body 4 itself controls the operation of the moving body 4.

[0095] In the above embodiment, the communication system 100 is a system for transmitting data between the in-vehicle device 1 mounted on the mobile object 4 and the base station 2 for remote control or the like, but the field to which this system is applied is not particularly limited. For example, the communication system 100 may be applied to the medical field. It is assumed that a communication device mounted on an ambulance is communicably connected to a terminal installed in a hospital or the like via a base station. For example, when a medical worker is in an ambulance transporting a patient, the medical worker can provide first aid to the patient based on information from a doctor at the hospital received by the communication device.

[0096] Furthermore, for example, the CQI processing unit 110 of the in-vehicle device 1 may be configured without at least any of the movement information acquisition unit 112, the weather information acquisition unit 113, and the route information acquisition unit 114. [Explanation of symbols]

[0097] 1 In-vehicle device (second communication device, communication device) 2 Base station (first communication device, specific communication device) 100 Communication Systems 102 Receiving processing unit 103 Reference signal acquisition unit (standard signal acquisition unit) 104 Propagation path condition determination unit (determination unit) 116 CQI report transmission processing unit (propagation path information transmission unit) 203 Reference signal transmission unit (reference signal transmission unit)

Claims

1. A communication system including a first communication device and a second communication device that wirelessly transmit data to each other, The first communication device is a reference signal transmission unit configured to transmit to the second communication device a reference signal for determining a propagation path state, which is a state of a propagation path of data between the second communication device and the second communication device; The second communication device is a reference signal acquisition unit that acquires the reference signal from the first communication device; a determination unit that determines the propagation path state based on the acquired reference signal; a propagation path information transmission unit that generates propagation path information regarding the propagation path state based on the propagation path state determined by the determination unit and transmits the propagation path information to the first communication device; a reception processing unit that receives data transmitted in a communication mode corresponding to the propagation path state indicated by the propagation path information from the first communication device, A communication system in which, when downloading specified data via the first communication device, the propagation path information transmission unit generates propagation path information indicating a propagation path state that is lower than the actual propagation path state determined by the determination unit, and transmits the propagation path information to the first communication device.

2. the second communication device is an in-vehicle device mounted on a moving body capable of being driven in a plurality of driving modes, A driving method determination unit that determines whether the driving method of the moving object is set to a predetermined driving method, The communication system according to claim 1, wherein when the driving method determination unit determines that the driving method of the moving body is set to the predetermined driving method, the propagation path information transmission unit determines that this corresponds to a case where predetermined data is downloaded via the first communication device.

3. the second communication device is an in-vehicle device mounted on a moving object, A moving information acquisition unit that acquires moving information including at least a moving speed of the moving object, The communication system according to claim 1 , wherein the propagation path information transmitting unit generates the propagation path information by taking into account the movement information.

4. the second communication device is an in-vehicle device mounted on a moving object, A weather information acquisition unit that acquires weather information about the surroundings of the moving object is further provided, The communication system according to claim 1 , wherein the propagation path information transmitting unit generates the propagation path information by taking into account the meteorological information.

5. the second communication device is an in-vehicle device mounted on a moving object, A route information acquisition unit that acquires route information regarding a route along which the moving object is scheduled to move, The communication system according to claim 1 , wherein the propagation path information transmitting unit generates the propagation path information by taking into account the route information.

6. A communication device that wirelessly transmits data between a specific communication device, a reference signal acquisition unit that acquires a reference signal for determining a propagation path state, which is a state of a propagation path of data to the specific communication device; a determination unit that determines the propagation path state based on the acquired reference signal; a propagation path information transmission unit that generates propagation path information regarding the propagation path state based on the propagation path state determined by the determination unit and transmits the propagation path information to the specific communication device; a reception processing unit that receives data transmitted in a communication mode corresponding to the propagation path state indicated by the propagation path information from the specific communication device, A communication device in which, when downloading specified data via the specific communication device, the propagation path information transmission unit generates the propagation path information indicating a propagation path state that is lower than the actual propagation path state determined by the determination unit, and transmits the propagation path information to the specific communication device.

7. A computer included in a communication device that wirelessly transmits data between a specific communication device, an acquisition step of acquiring a reference signal for determining a propagation path state, which is a state of a propagation path of data between the specific communication device and the specific communication device; a determination step of determining the propagation path state based on the acquired reference signal; a propagation path information transmitting step of generating propagation path information relating to the propagation path state based on the propagation path state determined in the determining step, and transmitting the propagation path information to the specific communication device; a receiving step of receiving data transmitted from the specific communication device in a communication mode corresponding to the propagation path state indicated by the propagation path information; In the propagation path information transmission process, when specific data is downloaded via the specific communication device, a process is executed to generate propagation path information indicating a propagation path state that is lower than the actual propagation path state determined in the determination process, and to transmit the propagation path information to the specific communication device.

8. A communication method executed by a communication device for wirelessly transmitting data between a specific communication device, comprising: an acquisition step of acquiring a reference signal for determining a propagation path state, which is a state of a propagation path of data between the specific communication device and the specific communication device; a determination step of determining the propagation path state based on the acquired reference signal; a propagation path information transmitting step of generating propagation path information relating to the propagation path state based on the propagation path state determined in the determining step, and transmitting the propagation path information to the specific communication device; a receiving step of receiving data transmitted in a communication mode corresponding to the propagation path state indicated by the propagation path information from the specific communication device, In the propagation path information transmission step, when downloading specified data via the specific communication device, a process is executed to generate propagation path information indicating a propagation path state that is lower than the actual propagation path state determined in the determination step, and to transmit the propagation path information to the specific communication device.

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