Communication system, communication method, and program

Abstract

In order to execute stable communication even when the speed of a vehicle is fast, 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. The communication means communicates, on the basis of the speed information, with the vehicle by using a first bandwidth when the speed is a first speed, and communicates with the vehicle by using a second bandwidth narrower than the first bandwidth when the speed is a second speed faster than the first speed.

Description

Technical Field

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

Background Art

[0002] Road-vehicle communication for communicating between a roadside device provided near a road and a vehicle traveling on the road is known. In road-vehicle 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 for communicating between vehicles 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 road-vehicle 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 selecting a frequency with a lower priority as the vehicle speed decreases. Also, Patent Document 2 discloses forming a wireless zone that covers up to the inside of an intersection in order to realize road-vehicle communication for an intersection accident prevention service. Further, Patent Document 3 discloses switching a wireless channel according to the vehicle speed information of a vehicle.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in general vehicle-to-roadside communication, vehicle-to-vehicle communication, and the technologies described in Patent Documents 1-3, the signals used for communication are transmitted toward vehicles in motion. Therefore, the faster the vehicle is traveling, the more unstable the communication becomes. Also, the wider the signal bandwidth, the more likely the SNR (Signal-to-Noise ratio) is to decrease. Therefore, in order to perform stable communication, it is necessary to transmit signals in a bandwidth corresponding to the speed of the vehicle. However, in the above-described technologies, signals are not transmitted in a bandwidth corresponding to the speed of the vehicle, so stable communication cannot be performed.

[0006] An object of the present invention is to provide, in view of the above problems, a communication system or the like capable of performing stable communication even when, for example, the speed of a vehicle is high.

Means for Solving the Problems

[0007] 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 bandwidth when the speed is a first speed; and communicates with the vehicle using a second bandwidth narrower than the first bandwidth when the speed is a second speed higher than the first speed.

[0008] 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 bandwidth when the speed based on the speed information is a first speed; and communicating with the vehicle using a second bandwidth narrower than the first bandwidth when the speed based on the speed information is a second speed higher than the first speed, the communication method.

[0009] The present invention also relates to a storage medium storing a program that causes an information processing apparatus to execute: a process of detecting speed information corresponding to the speed of a vehicle; a process of communicating with the vehicle using a first band when the speed based on the speed information is a first speed; a process of communicating with the vehicle using a second band narrower than the first band when the speed based on the speed information is a second speed higher than the first speed.

Advantages of the Invention

[0010] According to the present invention, for example, even when the speed of the vehicle is high, stable communication can be executed.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0012] <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.

[0013] 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 vehicles 10A and 10B, each of vehicles 10A and 10B will be referred to as vehicle 10 in the following description.

[0014] 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)), cellular communication technologies such as LTE (Long Term Evolution), 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.

[0015] 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 held by a pedestrian walking in the vicinity.

[0016] Note that the communication means 21, the detection means 22, the imaging means 23, and the 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, the detection means 22, the imaging means 23, and the position information acquisition means 24.

[0017] The communication means 21, the detection means 22, the imaging means 23, and the position information acquisition means 24 are connected to be mutually communicable. Also, the communication means 21 is connected to be communicable with the vehicle 10.

[0018] 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.

[0019] 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 the state of the vehicle 10 corresponding to speeds such as "high speed", "low speed", "stop", etc. in addition to the speed at which the vehicle 10 travels.

[0020] Second, the detection means 22 may acquire 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 traffic light color. For example, the detection means 22 communicates with the vehicle 10 via the communication means 21 and acquires 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 of the vehicle 10 is included in the range targeted by the instruction and that is located in the direction in which the vehicle 10 approaches. Note that the detection means 22 may acquire 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.

[0021] The detection means 22 acquires the content of the instruction given by the identified signal device to the vehicle 10, and acquires speed information corresponding to the instruction. Specifically, when the signal device instructs the vehicle 10 to stop, the detection means 22 acquires speed information indicating that the speed of the vehicle 10 is zero or speed information indicating that the vehicle 10 is stopped. Also, when the signal device instructs the vehicle 10 to pass, the detection means 22 acquires 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.

[0022] Third, the detection means 22 may further acquire 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.

[0023] The detection means 22 acquires speed information based on the image of the vehicle 10. Specifically, the detection means 22 analyzes the movement amount of the vehicle 10 in the image and obtains the speed of the vehicle 10. The detection means 22 acquires the obtained speed as speed information. It is assumed that known techniques are used for the analysis of the image.

[0024] 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.

[0025] 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 stores in advance 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 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.

[0026] The communication means 21 determines the bandwidth 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 (for example, 50 km / h), the communication means 21 communicates with the vehicle 10 using a first bandwidth (for example, 400 MHz millimeter wave). Further, when the speed information corresponds to a second speed (for example, 80 km / h) higher than the first speed, the communication means 21 communicates with the vehicle 10 using a second bandwidth (for example, Sub6 in the 100 MHz band) narrower than the first bandwidth. 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 (for example, the state of the vehicle 10 corresponding to the speed such as "high speed", "low speed", "stop", etc.).

[0027] 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 bandwidth and at the second bandwidth.

[0028] FIG. 2 shows the communication device 20, the vehicle 10A, and the 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 the second speed which is higher than the first speed. In this case, as described above, the communication device 20 communicates with the vehicle 10A at the first bandwidth and communicates with the vehicle 10B at the second bandwidth which is narrower than the first bandwidth.

[0029] Generally in wireless communication, a signal with a narrower bandwidth has less SNR degradation than a signal with a wider bandwidth. Therefore, in the communication system 1, a vehicle with a higher speed can communicate stably using a signal with a narrower bandwidth.

[0030] 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.

[0031] 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 bandwidth narrower than the aforementioned first bandwidth and second bandwidth (for example, an 18 MHz LTE band).

[0032] 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.

[0033] The communication means 21 outputs 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 obtained 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.

[0034] The detection means 22 outputs the detected speed information to the communication means 21 (S105). The communication means 21 determines the bandwidth 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 a first bandwidth. Also, when the speed information corresponds to a second speed higher than the first speed, the communication means 21 determines to use a second bandwidth narrower than the first bandwidth.

[0035] For example, when the speed indicated by the speed information is less than or equal to the threshold, 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, the communication means 21 determines to use Sub6 in the 3.7 GHz band or 4.5 GHz band.

[0036] Also, for example, when the state indicated by the speed information is "low speed" or "stopped", 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.

[0037] The communication means 21 communicates with the vehicle 10 using the determined bandwidth (S107). The communication means 21 performs communication with the vehicle 10 to establish a 5G communication session with an in-vehicle device in the vehicle 10, the lighting state of a nearby signal device, the approach of an emergency vehicle such as an ambulance, advertisements from nearby stores, driving support messages, alerts, etc., and transmits and receives information indicating the same.

[0038] In the above description of the operation, it is 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 a signal device that issues an instruction to the vehicle 10. Further, 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.

[0039] 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 bandwidth. Further, 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 bandwidth narrower than the first bandwidth.

[0040] As described above, in order to perform stable communication, it is preferable for the vehicle to communicate using a bandwidth corresponding to the speed. However, in the related art, there was no means for that. However, in the communication system 1, the vehicle 10 with a high speed can communicate using a wireless signal with a narrower bandwidth. Therefore, since the communication system 1 can use a narrow-band signal for which the SNR is less likely to deteriorate when the vehicle 10 is moving at a high speed, stable communication can be performed. <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 the communication system 2. FIG. 5 is a flowchart showing an operation example of the communication system 2.

[0041] As shown in FIG. 4, the 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 the communication system 2 may have the same functions and connection relationships as the communication means 21 and the detection means 22 of the communication system 1.

[0042] 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 based on the speed information, the communication means 21 communicates with the vehicle using the first bandwidth. 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 bandwidth narrower than the first bandwidth.

[0043] 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 gives an instruction to the vehicle. Further, the detection means 22 may acquire speed information based on an image of the vehicle captured by imaging means provided outside. Additionally, the detection means 22 may acquire speed information based on the position information of the vehicle 10 obtained by GPS or GNSS.

[0044] Next, an operation example of the communication system 2 will be described with reference to FIG. 5.

[0045] 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 bandwidth. Also, 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 bandwidth narrower than the first bandwidth. Note that the bandwidth 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). Note that the second embodiment also shows a communication method including the processes of S201 and S202. Also, the second embodiment also shows a storage medium that stores a program for causing an information processing apparatus to execute the processes of S201 and S202.

[0046] 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 bandwidth. Further, when the speed of the vehicle is the second speed higher than the first speed, the communication means 21 communicates with the vehicle using the second bandwidth narrower than the first bandwidth.

[0047] As described above, in order to perform stable communication, it is preferable that the vehicle travels within the 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.

[0048] 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 at which the vehicle moves between cells, so that the vehicle can perform stable communication.

[0049] Also, some or all of the components of each device or system are realized by an arbitrary combination of, for example, an information processing device 2000 and a program as shown in FIG. 6. FIG. 6 is a diagram showing an example of an information processing device that realizes the communication systems 1, 2, etc. The information processing device 2000 includes, as an example, the following configuration.

[0050] · 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 to recording medium 2006 · Communication interface 2008 that connects to communication network 2009 · Input / Output Interface 2010 for data input / output · Bus 2011 for connecting each component In each embodiment, each component of each device 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, for example, the storage device 2005 or the RAM 2003 in advance, 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 the recording medium 2006 in advance, and the drive device 2007 may read out the program and supply it to the CPU 2001.

[0051] There are various variations in the realization method of each device. For example, each device may be realized by an arbitrary combination of a separate information processing device 2000 and a program for each component. Also, a plurality of components included in each device may be realized by an arbitrary combination of one information processing device 2000 and a program.

[0052] Also, some or all of each component of each device are realized by a general-purpose or dedicated circuit (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. Some or all of each component of each device may be realized by a combination of the above-described circuit or the like and a program.

[0053] When some or all of each component of each device are realized by a plurality of information processing devices, circuits, etc., the plurality of information processing devices, circuits, etc. may be centrally arranged or may be distributed. For example, each of the information processing devices, circuits, etc. may be realized 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.

Explanation of Reference Numerals

[0054] 1. 2 Communication System 10, 10A, 10B Vehicles 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 Connecting Each Component

Claims

1. A communication means for communicating with a vehicle, and a detection means for detecting speed information corresponding to the speed of the vehicle, wherein the communication means, based on the speed information, when the speed is a first speed, communicates with the vehicle using a first bandwidth, and when the speed is a second speed higher than the first speed, communicates with the vehicle using a second bandwidth narrower than the first bandwidth. A communication system.

2. The detection means obtains 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 an imaging means for imaging the vehicle, wherein the detection means obtains the speed information based on an image of the vehicle captured by the imaging means. The communication system according to claim 1.

4. Further comprising a position information acquisition means for acquiring position information of the vehicle, wherein the detection means obtains 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 bandwidth, and when the speed based on the speed information is a second speed higher than the first speed, communicate with the vehicle using a second bandwidth narrower than the first bandwidth. 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 bandwidth when the speed based on the speed information is a first speed, When the speed based on the speed information is a second speed faster than the first speed, a process of communicating with the vehicle using a second bandwidth narrower than the first bandwidth. A program that causes an information processing device to execute.

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