Communication system, communication method, and program

Abstract

In order to realize stable communication even when the speed of a vehicle is high, for example, this communication system comprises a communication means for communicating with the vehicle, and a detection means for detecting speed information corresponding to the speed of the vehicle. On the basis of the speed information, the communication means communicates with the vehicle by using a first frequency when the speed is a first speed, and communicates with the vehicle by using a second frequency lower than the first frequency when the speed is a second speed higher than the first speed.

Description

Technical Field

[0001] The present invention relates to a communication system or the like that can perform stable communication even when, for example, the speed of a vehicle is high.

Background Art

[0002] Vehicle-roadside communication, which performs communication between a roadside device provided near a road and a vehicle traveling on the road, is known. In vehicle-roadside communication, for example, a vehicle transmits its own vehicle information to a roadside device, and the roadside device grasps the surrounding situation and transmits information to another vehicle running around, thereby alerting the driver and preventing a collision accident. Also, vehicle-to-vehicle communication, in which vehicles communicate with each other, is known. In vehicle-to-vehicle communication, for example, at an intersection with poor visibility, vehicles can wirelessly transmit and receive their own vehicle information such as their positions and speeds to and from each other, thereby warning the driver and preventing a collision accident. Further, in general vehicle-roadside communication and vehicle-to-vehicle communication, a vehicle can receive information such as the surrounding traffic situation and advertisements and provide it to the passengers of the vehicle.

[0003] For example, as a reference technique, Patent Document 1 discloses that in a wireless transmission device mounted on a moving body such as a traveling vehicle, by giving a frequency shift set based on the speed of the moving body to a transmitted wireless signal, the influence of Doppler shift is reduced.

[0004] Also, Patent Document 2 discloses that an in-vehicle wireless terminal switches between wireless communication methods with different used frequency bands.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in general vehicle-to-infrastructure communication, vehicle-to-vehicle communication, and the technologies described in Patent Document 1 and Patent Document 2, the signals used for communication are transmitted from communication devices such as base stations, roadside units, and vehicles to the vehicle. Therefore, in order to perform stable communication, it is preferable for the vehicle to travel within the range (cell) where signals from the communication device can reach for a certain period of time. However, in the above-described technologies, when the speed of the vehicle is high, the vehicle moves between a plurality of cells in a short period of time, so stable communication cannot be performed.

[0007] An object of the present invention is to provide a communication system or the like that can perform stable communication even when, for example, the speed of the vehicle is high, in view of the above problems.

Means for Solving the Problems

[0008] The present invention is a communication system, comprising: communication means for communicating with a vehicle; detection means for detecting speed information corresponding to the speed of the vehicle, wherein the communication means, based on the speed information, communicates with the vehicle using a first frequency when the speed is a first speed; and communicates with the vehicle using a second frequency lower than the first frequency when the speed is a second speed higher than the first speed.

[0009] Further, the present invention is a communication method, comprising: detecting speed information corresponding to the speed of a vehicle; communicating with the vehicle using a first frequency when the speed based on the speed information is a first speed; and communicating with the vehicle using a second frequency lower than the first frequency when the speed based on the speed information is a second speed higher than the first speed. Communication method.

[0010] Further, the present invention is a storage medium, A process of detecting speed information according to the speed of a vehicle, When the speed based on the speed information is the first speed, a process of communicating with the vehicle using a first frequency, When the speed based on the speed information is a second speed higher than the first speed, a process of communicating with the vehicle using a second frequency lower than the first frequency, Stores a program for causing an information processing apparatus to execute.

Advantages of the Invention

[0011] According to the present invention, it is possible to execute stable communication even when, for example, the speed of the vehicle is high.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0013] <First Embodiment> The communication system 1 in the first embodiment will be described with reference to FIGS. 1, 2, and 3. FIG. 1 is a block diagram showing a configuration example of the communication system 1. FIG. 2 is a diagram for explaining the details of the communication system 1. FIG. 3 is a flowchart for explaining an operation example of the communication system 1.

[0014] The communication system 1 includes vehicles 10A and 10B and a communication device 20. In the following description, when it is not necessary to distinguish between each of the vehicles 10A and 10B, each of the vehicles 10A and 10B will be referred to as vehicle 10 in the following description.

[0015] The vehicle 10 is a vehicle capable of traveling and includes an in-vehicle device capable of wireless communication. The vehicle 10 communicates with the communication device 20 by an in-vehicle device provided in the vehicle 10. That is, the vehicle 10 is communicably connected to the communication device 20. For communication, vehicle-to-vehicle communication or road-vehicle communication technologies such as DSRC (Dedicated Short Range Communications), C-V2X (Cellular-V2X (Vehicle-to-Everything)), NR-V2X (New Radio-V2X (Vehicle-to-Everything)), and cellular communication technologies such as LTE (Long Term Evolution) and 5G (Generation), and wireless communication technologies such as WiFi (registered trademark) are used. When communication is performed using 5G, the vehicle 10 can use frequency bands called Sub6 and millimeter waves.

[0016] The communication device 20 includes a communication means 21, a detection means 22, an imaging means 23, and a position information acquisition means 24. The communication device 20 is, for example, a roadside device provided on the side of the road on which the vehicle 10 travels. Further, the communication device 20 may be an in-vehicle device provided in another vehicle, or may be a smartphone or the like possessed by a pedestrian walking in the vicinity.

[0017] Note that the communication means 21, detection means 22, imaging means 23, and position information acquisition means 24 may each be provided in a separate device. Also, in FIG. 1, the communication system 1 is described as including the vehicle 10A and the vehicle 10B, but the vehicle 10A and the vehicle 10B are not essential components of the communication system 1. That is, the communication system 1 may be composed only of the communication means 21, detection means 22, imaging means 23, and position information acquisition means 24.

[0018] The communication means 21, detection means 22, imaging means 23, and position information acquisition means 24 are connected to be communicable with each other. Also, the communication means 21 is connected to be communicable with the vehicle 10.

[0019] The communication means 21 communicates with the vehicle 10. For example, the communication means 21 establishes a communication session with an in-vehicle device in the vehicle 10, transmits and receives information indicating the lighting state of a nearby signal device, the approach of an emergency vehicle such as an ambulance, an advertisement from a nearby store, a driving support message, an alert, etc. by communicating with the vehicle 10.

[0020] First, the detection means 22 detects speed information corresponding to the speed of the vehicle 10. For example, the detection means 22 communicates with the vehicle 10 by wireless communication such as LTE via the communication means 21. Thereby, the detection means 22 acquires the speed at which the vehicle 10 travels as speed information. Note that the speed information may indicate a state of the vehicle 10 corresponding to a speed such as "high speed", "low speed", "stop", etc. in addition to the speed at which the vehicle 10 travels.

[0021] Second, the detection means 22 may obtain speed information corresponding to an instruction from a signal device that gives an instruction to the vehicle 10. Generally, the signal device gives an instruction to the vehicle by changing the light color. For example, the detection means 22 communicates with the vehicle 10 via the communication means 21 and obtains the position information and traveling direction of the vehicle 10. The detection means 22 stores in advance the position information of the traffic signal and the range targeted by the instruction of the signal device for each traffic signal, and identifies the signal device that gives an instruction to the vehicle 10 based on the position information and traveling direction of the vehicle 10. For example, the detection means 22 identifies, as the signal device that gives an instruction to the vehicle 10, a signal device whose position information includes the position information of the vehicle 10 and that is located in the direction in which the vehicle 10 is approaching. Note that the detection means 22 may obtain the position information of the traffic signal and the range targeted by the instruction of the signal device from an external server or the like instead of storing them in advance.

[0022] The detection means 22 obtains the content of the instruction given by the identified signal device to the vehicle 10, and obtains speed information corresponding to the instruction. Specifically, when the signal device instructs the vehicle 10 to stop, the detection means 22 obtains speed information indicating that the speed of the vehicle 10 is zero or speed information indicating that the vehicle 10 is stopped. When the signal device instructs the vehicle 10 to pass, the detection means 22 obtains speed information indicating the legal speed of the road where the signal device is provided or speed information indicating the state of the vehicle 10 (for example, classification such as "high speed" or "low speed") corresponding to the legal speed. In this example, it is assumed that the signal device stores in advance the legal speed of the road where it is provided.

[0023] Third, the detection means 22 may obtain speed information based on an image of the vehicle 10 captured by the imaging means 23. The imaging means 23 has a function of imaging the vehicle 10. The imaging means 23 is, for example, a camera or the like and is provided in the communication device 20. Note that the imaging means 23 may be provided in a device different from the communication device 20. In this case, the imaging means 23 transmits the captured image to the detection means 22 via the communication means 21.

[0024] The detection means 22 acquires speed information based on the image of the vehicle 10. Specifically, the detection means 22 analyzes the amount of movement of the vehicle 10 in the image and determines the speed of the vehicle 10. The detection means 22 acquires the determined speed as speed information. It is assumed that known techniques are used for the analysis of the image.

[0025] Fourthly, the detection means 22 acquires speed information based on the position information of the vehicle 10 acquired by the position information acquisition means 24. In this example, it is assumed that the vehicle 10 acquires the position information of the vehicle by, for example, GPS (Global Positioning System) or GNSS (Global Navigation Satellite System). The detection means 22 acquires the position information of the vehicle 10 by communicating with the vehicle 10 by wireless communication such as LTE.

[0026] The detection means 22 acquires speed information based on the position information of the vehicle 10. Specifically, it is assumed that the detection means 22 has previously stored the correspondence between the position information and the speed information. For example, it is assumed that the legal speed of the road where the position indicated by the position information exists is associated with the position information as the speed information. The detection means 22 acquires the position information of the vehicle 10 and acquires the speed information corresponding to the position information as the speed information of the vehicle 10.

[0027] The communication means 21 determines the frequency to be used for communication with the vehicle 10 based on the speed information detected by the detection means 22. For example, when the speed information corresponds to a first speed (e.g., 50 km / h), the communication means 21 communicates with the vehicle 10 using a first frequency (e.g., millimeter wave in the 28 GHz band). Also, when the speed information corresponds to a second speed (e.g., 80 km / h) higher than the first speed, the communication means 21 communicates with the vehicle 10 using a second frequency lower than the first frequency (e.g., Sub6 in the 3.7 GHz band or 4.5 GHz band). The above "the speed information corresponds to the first speed" specifically means that the speed information indicates the first speed. Or, the above description means that the speed information indicates the state of the vehicle 10 corresponding to the first speed (e.g., the state of the vehicle 10 corresponding to speeds such as "high speed", "low speed", "stop", etc.).

[0028] Next, the details of the communication system 1 will be described with reference to FIG. 2. FIG. 2 is a block diagram for explaining the details when communicating between the communication device 20 and the vehicle 10 at the first frequency and when communicating at the second frequency.

[0029] FIG. 2 shows a communication device 20, a vehicle 10A, and a vehicle 10B. In this example, it is assumed that the vehicle 10A is traveling at the first speed and the vehicle 10B is traveling at a second speed higher than the first speed. In this case, as described above, the communication device 20 communicates with the vehicle 10A at the first frequency and communicates with the vehicle 10B at a second frequency lower than the first frequency.

[0030] Generally, in wireless communication, a signal with a lower frequency propagates over a wider range than a signal with a higher frequency. Therefore, as shown in FIG. 2, the wireless signal having the first frequency propagates to cell C1, and the wireless signal having the second frequency propagates within a cell C2 wider than cell C1. For this reason, in the communication system 1, a vehicle with a higher speed can communicate using a wireless signal that propagates in a wider cell.

[0031] Next, the operation of the communication system 1 will be described with reference to FIG. 3. FIG. 3 is a flowchart showing the operation of the communication system 1.

[0032] The communication means 21 transmits a response request signal to vehicles within a predetermined range (S101). It is assumed that the communication means 21 transmits the response request signal at a frequency lower than the aforementioned first frequency and second frequency (for example, an LTE band of 700 MHz to 900 MHz).

[0033] In response to receiving the response request signal, the vehicle 10 transmits a response signal to the communication means 21 (S102). At this time, the vehicle 10 transmits a response signal including information indicating the speed of the vehicle 10 to the communication means 21.

[0034] The communication means 21 outputs the information indicating the speed included in the response signal to the detection means 22 (S103). The detection means 22 detects speed information based on the information acquired from the communication means 21 (S104). The detection means 22 may detect the speed of the vehicle 10 as speed information, or may detect the state of the vehicle 10 corresponding to the speed (for example, classification such as "high speed", "low speed", or "stopped") as speed information.

[0035] The detection means 22 outputs the detected speed information to the communication means 21 (S105). The communication means 21 determines the frequency to be used for communication with the vehicle 10 based on the speed information (S106). Specifically, when the speed information corresponds to a first speed, the communication means 21 determines to use the first frequency. Also, when the speed information corresponds to a second speed higher than the first speed, the communication means 21 determines to use a second frequency lower than the first frequency.

[0036] For example, when the speed indicated by the speed information is equal to or lower than the threshold value, the communication means 21 determines to use millimeter waves in the 28 GHz band. Also, when the speed indicated by the speed information exceeds the threshold value, the communication means 21 determines to use Sub6 in the 3.7 GHz band or 4.5 GHz band.

[0037] For example, when the state indicated by the speed information is "low speed" or "stop", the communication means 21 determines to use millimeter waves in the 28 GHz band. Also, when the state indicated by the speed information is "high speed", the communication means 21 determines to use Sub6 in the 3.7 GHz band or 4.5 GHz band.

[0038] The communication means 21 communicates with the vehicle 10 using the determined frequency (S107). Through communication with the vehicle 10, the communication means 21 establishes a 5G communication session with the in-vehicle device in the vehicle 10, transmits and receives information indicating the lighting state of the nearby signal device, the approach of emergency vehicles such as ambulances, advertisements from nearby stores, driving support messages, alerts, etc.

[0039] In the above description of the operation, it was assumed that the detection means 22 detects the speed information based on the information included in the response signal. On the other hand, as described above, the detection means 22 may acquire the speed information corresponding to the instruction from the signal device that issues an instruction to the vehicle 10. Also, the detection means 22 may acquire the speed information based on the video of the vehicle 10 captured by the imaging means 23. Further, the detection means 22 may acquire the speed information based on the position information of the vehicle 10 acquired by the position information acquisition means 24.

[0040] As described above, in the communication system 1, when the speed of the vehicle 10 is the first speed based on the speed information, the communication means 21 communicates with the vehicle 10 using the first frequency. Also, when the speed of the vehicle 10 is the second speed higher than the first speed, the communication means 21 communicates with the vehicle 10 using the second frequency lower than the first frequency.

[0041] As described above, in order to perform stable communication, it is preferable for the vehicle to travel within the range (cell) where signals from the communication device can reach for a certain period of time. However, in related technologies, when the vehicle speed is high, the vehicle moves between a plurality of cells in a short period of time, so handover is required and the vehicle cannot perform stable communication.

[0042] However, in communication system 1, the fast vehicle 10 can communicate using a low-frequency radio signal that propagates through a wide cell. Therefore, communication system 1 can reduce the frequency at which vehicle 10 moves between cells, so that vehicle 10 can perform stable communication. <Second Embodiment> The communication system 2 according to the second embodiment will be described with reference to FIGS. 4 and 5. FIG. 4 is a block diagram showing a configuration example of communication system 2. FIG. 5 is a flowchart showing an operation example of communication system 2.

[0043] As shown in FIG. 4, communication system 2 includes a communication means 21 and a detection means 22. Note that the communication means 21 and the detection means 22 of communication system 2 may have the same functions and connection relationships as the communication means 21 and the detection means 22 of communication system 1.

[0044] The communication means 21 communicates with a vehicle (not shown). The detection means 22 detects speed information corresponding to the speed of the vehicle. When the speed of the vehicle is the first speed, the communication means 21 communicates with the vehicle using the first frequency based on the speed information. Also, when the speed of the vehicle is a second speed higher than the first speed, the communication means 21 communicates with the vehicle using a second frequency lower than the first frequency.

[0045] Note that the detection means 22 detects speed information corresponding to the speed of the vehicle, for example, by communicating with the vehicle. Also, the detection means 22 may acquire speed information corresponding to the instruction from a signal device that issues an instruction to the vehicle. Further, the detection means 22 may acquire speed information based on an image of the vehicle captured by an imaging means provided outside. Also, the detection means 22 may acquire speed information based on the position information of vehicle 10 obtained by GPS or GNSS.

[0046] Next, an operation example of communication system 2 will be described with reference to FIG. 5.

[0047] The detection means 22 detects speed information corresponding to the speed of the vehicle (S201). The communication means 21 communicates with the vehicle (S202). In the process of S202, when the speed corresponding to the speed information is the first speed, the communication means 21 communicates with the vehicle using the first frequency. When the speed corresponding to the speed information is a second speed higher than the first speed, the communication means 21 communicates with the vehicle using a second frequency lower than the first frequency. Note that the frequency used for communication with the vehicle in the process of S202 is determined by the communication means 21, the detection means 22, or a configuration (not shown). The second embodiment also shows a communication method including the processes of S201 and S202. The second embodiment also shows a storage medium storing a program for causing an information processing apparatus to execute the processes of S201 and S202.

[0048] As described above, in the communication system 2, when the speed of the vehicle is the first speed based on the speed information, the communication means 21 communicates with the vehicle using the first frequency. When the speed of the vehicle is a second speed higher than the first speed, the communication means 21 communicates with the vehicle using a second frequency lower than the first frequency.

[0049] As described above, in order to perform stable communication, it is preferable that the vehicle travels within a range (cell) where signals from the communication device can reach for a certain period of time. However, in the related art, when the speed of the vehicle is high, the vehicle moves between a plurality of cells in a short period of time, so handover is required and the vehicle cannot perform stable communication.

[0050] However, in the communication system 2, a vehicle with a high speed can communicate using a low-frequency radio signal that propagates through a wide cell. Therefore, the communication system 2 can reduce the frequency with which the vehicle moves between cells, so that the vehicle can perform stable communication.

[0051] Further, part or all of each component of each device or system is realized by an arbitrary combination of an information processing apparatus 2000 and a program as shown in FIG. 6, for example. FIG. 6 is a diagram showing an example of an information processing apparatus that realizes communication systems 1, 2, etc. The information processing apparatus 2000 includes the following configuration as an example.

[0052] ·CPU (Central Processing Unit) 2001 ·ROM (Read Only Memory) 2002 ·RAM (Random Access Memory) 2003 ·Program 2004 loaded into RAM 2003 ·Storage device 2005 that stores program 2004 ·Drive device 2007 that reads and writes recording medium 2006 ·Communication interface 2008 connected to communication network 2009 ·Input / output interface 2010 that performs input / output of data ·Bus 2011 that connects each component Each component of each device in each embodiment is realized by the CPU 2001 acquiring and executing a program 2004 that realizes these functions. The program 2004 that realizes the functions of each component of each device is stored in advance in the storage device 2005 or the RAM 2003, for example, and is read out by the CPU 2001 as needed. Note that the program 2004 may be supplied to the CPU 2001 via the communication network 2009, or may be stored in advance in the recording medium 2006, and the drive device 2007 may read out the program and supply it to the CPU 2001.

[0053] There are various modifications to the method of realizing each device. For example, each device may be realized by an arbitrary combination of a separate information processing apparatus 2000 and a program for each component. Further, a plurality of components included in each device may be realized by an arbitrary combination of one information processing apparatus 2000 and a program.

[0054] Also, part or all of each component of each device is implemented by a general-purpose or dedicated circuitry including a processor or the like, or a combination thereof. These may be constituted by a single chip, or may be constituted by a plurality of chips connected via a bus. Part or all of each component of each device may be implemented by a combination of the above-described circuitry or the like and a program.

[0055] When part or all of each component of each device is implemented by a plurality of information processing devices, circuitry, or the like, the plurality of information processing devices, circuitry, or the like may be centrally arranged or may be distributed. For example, each of the information processing devices, circuitry, or the like may be implemented in a form connected via a communication network. Note that examples of the communication network include a client and server system, a cloud computing system, and the like.

Description of Reference Numerals

[0056] 1, 2 Communication system 10, 10A, 10B Vehicle 20 Communication device 21 Communication means 22 Detection means 23 Imaging means 24 Position information acquisition means 2001 CPU 2002 ROM 2003 RAM 2004 Program 2005 Storage device 2007 Drive device 2008 Communication interface 2009 Communication network 2010 Input / output interface 2011 Bus for connecting each component

Claims

1. Communication means for communicating with a vehicle, Detection means for detecting speed information corresponding to the speed of the vehicle, and comprising: Based on the speed information, the communication means When the speed is a first speed, communicates with the vehicle using a first frequency, When the speed is a second speed higher than the first speed, communicates with the vehicle using a second frequency lower than the first frequency. A communication system.

2. The detection means acquires the speed information corresponding to the instruction from a signal device that issues an instruction to the vehicle. The communication system according to Claim 1.

3. Further comprising imaging means for imaging the vehicle, The detection means acquires the speed information based on an image of the vehicle imaged by the imaging means. The communication system according to Claim 1.

4. Further comprising position information acquisition means for acquiring position information of the vehicle, The detection means acquires the speed information based on the position information of the vehicle acquired by the position information acquisition means. The communication system according to Claim 1.

5. Detect speed information corresponding to the speed of a vehicle, When the speed based on the speed information is a first speed, communicate with the vehicle using a first frequency, When the speed based on the speed information is a second speed higher than the first speed, communicate with the vehicle using a second frequency lower than the first frequency. A communication method.

6. A process of detecting speed information corresponding to the speed of a vehicle, A process of communicating with the vehicle using a first frequency when the speed based on the speed information is a first speed, A process of communicating with the vehicle using a second frequency lower than the first frequency when the speed based on the speed information is a second speed higher than the first speed. A program for causing an information processing apparatus to execute.

Images