JP7293849B2 - INFORMATION TRANSFER DEVICE, VEHICLE DEVICE, SYSTEM, INFORMATION TRANSFER METHOD, AND COMPUTER PROGRAM - Google Patents

Description

The present disclosure relates to an information transfer device, an in-vehicle device, a system, an information transfer method, and a computer program.

BACKGROUND ART Various systems (hereinafter referred to as driving assistance systems) have been proposed for assisting drivers in driving automobiles, motorcycles, etc. (hereinafter referred to as vehicles). In the driving support system, sensor information is collected from roadside devices equipped with various sensor devices (cameras, radars, etc.) installed on the road and its surroundings, and analyzed to obtain traffic-related information (accidents, traffic jams, etc.). is provided to the vehicle as driving support information. In addition, with the speeding up of mobile communication lines, it has been proposed to collect information not only from sensors installed in roadside equipment, but also from sensors installed in vehicles, and use it effectively for driving support. . For example, 3GPP (Third Generation Partnership Project), which promotes the standardization of third-generation mobile communication systems and subsequent mobile communication systems, has proposed a standard called cellular V2X. V stands for Vehicle and X stands for something else. This standard aims at communication between vehicles and others by LTE (Long Term Evolution) and 5G (5th generation mobile communication system).

In addition to distributing driving support information from a server or the like via a mobile communication base station, information (sensor information, etc.) that can be used for driving support between in-vehicle devices installed in vehicles can be shared via the base station. Vehicle-to-vehicle communication has been proposed in which data is directly transmitted and received without data transmission. For example, in Patent Document 1 below, in order to reduce the packet transfer load of inter-vehicle communication, a vehicle group is autonomously formed by grouping multiple vehicles that run in close proximity, and the characteristics of this vehicle group are used. It is disclosed that packets are forwarded between groups using Specifically, the leading and trailing vehicles of the formed vehicle group are designated as relay vehicle stations that perform packet relay transfer with adjacent vehicle groups.

JP-A-2001-358641

Information used for driving support includes highly real-time information (e.g., dynamic information such as detected pedestrians) and non-real-time information (e.g., static information such as congestion and accident information). are mixed and transferred. Therefore, even though the life (effectively usable time) of the information to be transferred has expired (effectively usable time has passed), the transfer may be repeated, and such information may be repeatedly transferred. Then, there is a problem that useless communication traffic increases. This problem cannot be solved by US Pat.

Accordingly, an object of the present disclosure is to provide an information transfer device, an in-vehicle device, a system, an information transfer method, and a computer program that can suppress an increase in communication traffic due to repeated transfer of information whose life has ended.

An information transfer device according to an aspect of the present disclosure includes an acquisition unit that acquires information, a life calculation unit that calculates the life of the information acquired by the acquisition unit, and a delay time associated with information transfer processing and a life according to the life. a determination unit that determines whether to transfer the information, and a transmission unit that transmits the information in response to the determination by the determination unit that the information is to be transferred, and the lifetime is the time during which the information can be used. show.

An in-vehicle device according to another aspect of the present disclosure is an in-vehicle device mounted in a vehicle, and includes an acquisition unit that acquires information through wireless communication, and a life calculation unit that calculates the life of the information acquired by the acquisition unit. a determination unit that determines whether or not to transfer the information according to the delay time and lifespan associated with information transfer processing by wireless communication; The lifetime represents the time the information is available for use.

A system according to still another aspect of the present disclosure includes a first information transfer device and a second information transfer device that communicate with each other, wherein the first information transfer device includes a first acquisition unit that acquires information; a lifespan calculation unit for calculating the lifespan of information acquired by the acquisition unit; 1 determination unit, and a first transmission unit that transmits information and the number of times of transfer that represents the number of times that the transfer of the information is permitted in response to the determination by the first determination unit that the information is to be transferred. represents the time that can be used, and the second information transfer device includes a second acquisition unit that acquires the information transmitted from the first information transfer device, and the second acquisition unit that receives the number of times of transfer together with the information. a subtracting unit for determining a value obtained by subtracting 1 from the number of transfers as a new number of transfers; a determining unit; and a second transmitting unit that transmits information and a new number of transfers other than 0 in response to the fact that the second determining unit has determined to transfer.

An information transfer method according to yet another aspect of the present disclosure includes an acquisition step of acquiring information, a lifespan calculation step of calculating the lifespan of the information acquired by the acquisition step, and a delay time and a lifespan associated with the information transfer process. and a transmitting step of transmitting the information in response to the fact that the information is determined to be transferred by the determining step. represents time.

A computer program according to yet another aspect of the present disclosure provides a computer with an acquisition function for acquiring information, a lifespan calculation function for calculating the lifespan of the information acquired by the acquisition function, a delay time associated with information transfer processing, and A computer program for realizing a determination function for determining whether or not to transfer information according to its lifespan, and a transmission function for transmitting information in response to the determination by the determination function that the information should be transferred. As such, lifetime represents the time during which information can be used.

According to the present disclosure, it is possible to suppress an increase in communication traffic due to repeated transfer of information whose life has ended.

FIG. 1 is a schematic diagram showing the configuration of an information transfer system according to an embodiment of the present disclosure. FIG. 2 is a block diagram showing the hardware configuration of the in-vehicle device. FIG. 3 is a block diagram showing the hardware configuration of the server. FIG. 4 is a block diagram showing the functional configuration of the in-vehicle device. FIG. 5 is a flow chart showing the operation of the in-vehicle device. FIG. 6 is a flow chart showing the operation of the in-vehicle device according to the first modified example. FIG. 7 is a flow chart showing the operation of the in-vehicle device according to the second modification.

[Description of Embodiments of the Present Disclosure]
The contents of the embodiments of the present disclosure are listed and described. At least some of the embodiments described below may be combined arbitrarily.

(1) An information transfer device according to a first aspect of the present disclosure includes an acquisition unit that acquires information, a lifespan calculation unit that calculates the lifespan of information acquired by the acquisition unit, and a delay time associated with information transfer processing. and a determination unit that determines whether or not to transfer information according to the life and the life; Represents the time available.

As a result, it is possible to suppress an increase in communication traffic due to repeated transfer of information that cannot be used effectively.

(2) Preferably, the acquisition unit acquires additional information used to calculate the lifespan, the additional information includes at least generation time information representing the time at which the information was generated, and the lifespan calculation unit provides real-time information. The transmission delay time is calculated by subtracting the transmission delay time from the allowable delay time predetermined for each type, and the transmission delay time is from the time represented by the generation time information until the information is acquired by the acquisition unit. It's time for Thereby, the information transfer device can calculate the lifetime for each type of acquired information.

(3) More preferably, the delay time includes communication delay time and transfer processing time, and the communication delay time is a predicted value of the time from when the information is transferred from the information transfer device to when it is acquired by the external device. , the transfer processing time is a predicted value of the time required for the external device to acquire information and transfer it. Accordingly, the information transfer device can accurately determine whether or not to transfer information.

(4) More preferably, the determination unit includes a transfer count calculation unit that determines an integer value of 0 or more obtained by dividing the life calculated for each type by the delay time as the transfer count for each type. If at least one of the number of transfers for each type is 1 or more, it is determined that the information is to be transferred. This makes it possible to efficiently determine whether or not to transfer information. That is, if the number of times of all transfers becomes 0 after subtracting 1, it can be determined that retransfer is unnecessary.

(5) Preferably, the transmitting unit transmits at least one number of times of transfer that is equal to or greater than 1 together with the information. As a result, the external device can easily determine whether or not retransfer is necessary based on the number of transfers.

(6) More preferably, the determination unit calculates the lifespan by the lifespan calculation unit in response to the fact that the acquisition unit acquires the information together with the number of transfers for each type representing the number of times the transfer of the information is permitted. a subtraction unit for determining a value obtained by subtracting 1 from the number of transfers for each type without adding 1 to the number of transfers for each type as a new number of transfers for each type; is equal to or greater than 1, it is determined that the information is to be transferred. As a result, the retransfer destination device can easily determine whether or not retransfer is necessary based on the number of transfers.

(7) More preferably, the determination unit calculates the lifespan by the lifespan calculation unit in response to the fact that the acquisition unit acquires the information together with the number of transfers for each type representing the number of times the transfer of the information is permitted. a same data determination unit that determines whether the information is the same as the information transmitted from the transmission unit before acquiring the information, and the same data determination unit determines whether the information is the same as the information is the same as the information transmitted from the transmission unit before acquiring the information, it is determined not to transfer the information. As a result, it is possible to suppress an increase in communication traffic caused by transferring the same data again.

(8) An in-vehicle device according to a second aspect of the present disclosure is an in-vehicle device mounted in a vehicle, and includes an acquisition unit that acquires information by wireless communication, and a lifespan of the information acquired by the acquisition unit. a determination unit that determines whether or not to transfer information according to the delay time and the lifetime associated with information transfer processing by wireless communication; and a transmitter for wirelessly transmitting the information, and the lifetime represents the time during which the information is available. As a result, it is possible to suppress an increase in communication traffic due to repeated transfer of information that cannot be used effectively.

(9) Preferably, the transmission unit includes a directivity setting unit that sets the directivity of the transmission radio wave for wireless communication, and the directivity setting unit sets the direction of the information transmitted from the transmission unit to the direction opposite to the traveling direction of the vehicle. Set the directivity so that it is sent to As a result, it is possible to suppress an increase in communication traffic caused by transferring the same data again.

(10) A system according to a third aspect of the present disclosure includes a first information transfer device and a second information transfer device that communicate with each other, wherein the first information transfer device is a first acquisition unit that acquires information; a life calculation unit for calculating the life of the information acquired by the first acquisition unit; and a first transmission unit that transmits information and the number of times of transfer that represents the number of times that the transfer of the information is permitted in response to the fact that the first determination unit determines that the transfer is to be performed. represents the time that the information can be used, the second information transfer device is a second acquisition unit that acquires the information transmitted from the first information transfer device, and the second acquisition unit acquires the number of times of transfer together with the information. In response to this, a subtraction unit determines a value obtained by subtracting 1 from the number of transfers as a new number of transfers, and from the new number of transfers determined by the subtraction unit, it is determined whether or not to transfer information. and a second transmission unit for transmitting the information and a new number of transfers other than 0 in response to the second determination unit determining that the transfer is to be performed. As a result, it is possible to suppress an increase in communication traffic due to repeated transfer of information that cannot be used effectively.

(11) An information transfer method according to a fourth aspect of the present disclosure includes an acquisition step of acquiring information, a lifespan calculation step of calculating the lifespan of the information acquired by the acquisition step, and a delay time associated with information transfer processing. and a transmission step of transmitting the information in response to the fact that the information is determined to be transferred by the determination step. Represents the time available. As a result, it is possible to suppress an increase in communication traffic due to repeated transfer of information that cannot be used effectively.

(12) A computer program according to a fifth aspect of the present disclosure, comprising: an acquisition function for acquiring information; a lifespan calculation function for calculating the lifespan of information acquired by the acquisition function; A computer for realizing a determination function for determining whether or not to transfer information according to the delay time and life, and a transmission function for transmitting information in response to the determination by the determination function that the information should be transferred. In a program, lifetime represents the time that information can be used. As a result, it is possible to suppress an increase in communication traffic due to repeated transfer of information that cannot be used effectively.

[Details of the embodiment of the present disclosure]
In the following embodiments, identical parts are provided with identical reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

(embodiment)
[overall structure]
An information transfer system according to an embodiment of the present disclosure includes an in-vehicle device mounted in each of a plurality of vehicles. Referring to FIG. 1 , information transfer system 100 includes in-vehicle devices 112 , 114 and 116 mounted on vehicles 102 , 104 and 106 . Although FIG. 1 representatively shows three in-vehicle devices 112, 114 and 116, the information transfer system 100 may include in-vehicle devices installed in a plurality of vehicles.

Each of the in-vehicle devices 112 , 114 and 116 transmits and receives information via a mobile communication line (LTE line, 5G line, etc.) provided by the base station 122 . The in-vehicle devices 112 , 114 and 116 can also communicate with each other wirelessly without going through the base station 122 (hereinafter referred to as direct wireless communication). The information received by the in-vehicle devices 112, 114 and 116 includes driving support information. The driving support information includes not only information obtained by analyzing data acquired by a sensor (hereinafter referred to as sensor data or sensor information), but also sensor information itself.

The infrastructure sensor 120 is a device equipped with sensors installed on and around roads, and has a function of communicating with a server 124 via a network 126 . The sensor is, for example, an image sensor (digital surveillance camera, etc.), a radar (millimeter wave radar, etc.), a laser sensor (LiDAR, etc.), or the like. Infrastructure sensor 120 may have the ability to communicate with server 124 via base station 122 . FIG. 1 shows an object 128 to be detected by the sensor. The detection target 128 is also a detection target by onboard sensors of the vehicles 102, 104 and 106, which will be described later. The detection target 128 includes, for example, not only moving objects such as people and vehicles, but also traffic lights, buildings, and the like. Also, the infrastructure sensor 120 may have a function of directly wirelessly communicating with the in-vehicle devices 112 , 114 and 116 . In that case, infrastructure sensor 120 transmits sensor information directly to each of onboard devices 112 , 114 and 116 .

The server 124 is, for example, a server computer such as a traffic information providing server installed in a traffic control center or the like, and distributes traffic information (for example, traffic information such as congestion information and accident information). The server 124 also analyzes sensor information transmitted from the infrastructure sensor 120 to generate driving support information, and transmits the information to the in-vehicle devices 112 , 114 and 116 via the base station 122 .

Although FIG. 1 typically shows one infrastructure sensor 120, one server 124, and one base station 122, the present invention is not limited to this. There are typically multiple infrastructure sensors, multiple servers, and multiple base stations.

[Hardware configuration of in-vehicle device]
Referring to FIG. 2, an example of the hardware configuration of in-vehicle device 112 mounted in vehicle 102 is shown. The in-vehicle devices 114 and 116 mounted on the vehicle 104 and the vehicle 106 shown in FIG. The in-vehicle device 112 includes an interface unit (hereinafter referred to as an I/F unit) 142 connected to one or more sensors 140 mounted on the vehicle 102, a communication unit 144 for wireless communication, a memory 146 for storing data, It includes a control section 148 for controlling them and a bus 150 for exchanging data between the sections.

The sensor 140 is a video imaging device (for example, a digital camera (CCD camera, CMOS camera)) mounted on the vehicle 102, a laser sensor (LiDAR), or the like. If the sensor 140 is a digital camera, it outputs a predetermined video signal (analog signal or digital data). A signal from sensor 140 is input to I/F section 142 . The I/F unit 142 includes an A/D conversion unit, samples an analog signal at a predetermined frequency, and generates and outputs digital data. The generated digital data is transmitted to and stored in memory 146 . If the output signal from sensor 140 is digital data, I/F section 142 stores the input digital data in memory 146 . The memory 146 is, for example, a rewritable non-volatile semiconductor memory or HDD.

The communication unit 144 has a mobile communication function and performs wireless communication with the base station 122 and the infrastructure sensor 120 . The communication unit 144 also has a function of directly wirelessly communicating with an in-vehicle device mounted in another vehicle. The in-vehicle device 112 communicates via the base station 122 with in-vehicle devices mounted on other vehicles and devices connected to the network 126 that are out of reach of radio waves transmitted from the communication unit 144 . The communication unit 144 includes an IC for modulation and multiplexing employed in wireless communication, an antenna for transmitting and receiving radio waves of a predetermined frequency, an RF circuit, and the like.

The control unit 148 includes a CPU, and realizes the functions of the in-vehicle device 112 by controlling each unit. For example, the control unit 148 transmits the sensor data acquired from the sensor 140 to the server 124 and an in-vehicle device of another vehicle. The control unit 148 also receives driving support information from the server 124 and performs processing such as controlling the running of the vehicle 102 and displaying information to support the driver. In addition, the control unit 148 analyzes the data acquired by the sensor 140 to detect objects around the vehicle 102 and uses them for driving assistance.

[Server hardware configuration]
Referring to FIG. 3, server 124 includes control unit 160 , memory 162 , communication unit 164 and bus 166 . Server 124 is, for example, a computer. Data transmission between units occurs via bus 166 . The control unit 160 includes, for example, a CPU, controls each unit, and realizes various functions of the server 124 . The communication unit 164 receives sensor information and the like uploaded from the in-vehicle devices 112 , 114 and 116 and the infrastructure sensor 120 . The memory 162 includes a rewritable non-volatile semiconductor memory and a mass storage device such as an HDD. The data received by communication unit 164 is transmitted to memory 162 and stored as a database. Control unit 160 appropriately reads data from memory 162 , executes predetermined analysis processing (for example, analysis for obtaining driving support information), and stores the result in memory 162 . The control unit 160 reads driving support information and the like from the memory 162 as appropriate and transmits the information to the in-vehicle devices 112 , 114 and 116 .

[Hardware configuration of infrastructure sensor]
The infrastructure sensor 120 is different from the in-vehicle devices 112, 114, and 116 in that it is not mounted on the vehicle but is installed on the road and its surroundings, but its hardware configuration is basically the same as in FIG. . Since the infrastructure sensor 120 is fixedly installed, the communication function with the server 124 is optional. For example, even if it is a mobile communication line (LTE line or 5G line, etc.) for connecting to the base station 122, it may be a wired communication, or a wireless LAN communication such as WiFi (registered trademark). good.

[Functional configuration of in-vehicle device]
The functions of the in-vehicle device 112 will be described with reference to FIG. The in-vehicle devices 114 and 116 mounted on the vehicles 104 and 106 shown in FIG. 1 also have similar functions. The in-vehicle device 112 includes a packet receiver 170 , a packet transmitter 172 , a life calculator 174 , a communication delay estimator 176 , a transfer count calculator 178 , a determination unit 180 and a storage unit 182 .

When the packet receiving unit 170 receives packet data containing information (including sensor information) transmitted from the in-vehicle devices 114 and 116 of the vehicles 104 and 106, the infrastructure sensor 120, and the base station 122, the life calculating unit 174 and storage Output to unit 182 . The data output from the packet receiving unit 170, even if it is each packet data, is treated as a group of original data before packetization reconstructed from a plurality of packet data (for example, one frame of image data, etc.). data, and may be data including data as it is if it is compressed or the like.

The lifetime calculation unit 174 determines whether or not the data input from the packet reception unit 170 includes the number of times of transfer, which will be described later. On the other hand, if the number of transfers is not included, the life calculation unit 174 uses the information contained in the data to calculate and output the time τ (hereinafter referred to as life) during which the data can be effectively used. Specifically, the value obtained by subtracting the transmission delay ΔT2 from the allowable delay ΔT1 is defined as the life τ (τ=ΔT1−ΔT2).

The allowable delay ΔT1 is a preset time for effectively utilizing sensor information and the like for driving assistance and the like. From the perspective of use (application), the information used for various driving support is the time elapsed from the time when it was generated (for example, the time when the acquisition of sensor information treated as one unit (for example, one frame) was completed). It can be classified into a plurality of types depending on (that is, real-time property). For example, it can be classified into real-time, near-real-time, and non-real-time. Real-time means, for example, that the elapsed time from generation is one second or less. Quasi-real time means, for example, that the elapsed time from generation is longer than 1 second and shorter than 1 minute. Non-real-time means, for example, that the elapsed time since generation is more than one minute and several days (eg, five days) or less. Sensor information can be used effectively for applications that require real-time performance (collision avoidance processing, etc.) only for a very short time after it is generated, but if more time passes, it will not be used for applications that require real-time performance. become unable. However, the same sensor information can be effectively used over time for near-real-time applications (such as predictive processing) or non-real-time applications (such as statistical processing). For example, the allowable delay ΔT1 is set to 1 second, 1 minute and 5 days for real time, near real time and non-real time respectively. The permissible delay ΔT1 is received from an external device (server or the like) and stored in the storage unit 182 in advance. Allowable delay ΔT1 may be stored as an initial setting in a ROM (Read Only Memory) included in storage unit 182 or the like.

A transmission delay ΔT2 means a delay time caused by communication of data (sensor information, etc.). That is, the transmission delay ΔT2 is obtained by subtracting the time (Tp) at which the data was generated by the source device (server or the like) from the time (Tr) at which the data was received by the packet receiving unit 170 (ΔT2 =Tr-Tp). Therefore, the data transmitting/receiving device appropriately executes a process of synchronizing its own clock with the standard time. Here, it is assumed that the data generation time Tp is specified by the data transmission source (server 124, infrastructure sensor 120, vehicle-mounted devices 114 and 116, etc.) and added to transmission data (included in packet data).

The communication delay estimator 176 estimates and outputs a communication delay ΔT3 during transfer from the communication line speed used for transferring the data received by the packet receiver 170 . A communication delay is determined by a combination of the type of communication line used and its communication speed. For example, statistical values of communication delay for each communication line may be appropriately obtained in advance from a server or the like and stored in the storage unit 182 as a table. Further, the communication speed at the time of past communication in the own device (in-vehicle device 112 ) may be stored, and the storage unit 182 may store the result of calculating by summing up the speed as appropriate.

The number of transfers calculation unit 178 calculates the life τ (seconds) input from the life calculation unit 174, the communication delay ΔT3 (seconds) input from the communication delay estimation unit 176, and the transfer processing time ΔT4 (seconds) in the other in-vehicle device. ) to calculate and output the number of transfers N. Specifically, the number of transfers N is calculated by N=[τ/(ΔT3+ΔT4)]. The operator [ ] means the largest integer that does not exceed the value of the operation result in [ ]. As will be described later, if the data transfer count N is 0, the data is not transferred. It can also be interpreted as the number of times the transfer is permitted.

The transfer processing time ΔT4 means the time required from when data is transferred from the packet transmission unit 172 as described later, and when the data is received by another in-vehicle device until the received data is transferred again. Since τ, ΔT3 and ΔT4 are positive values, N is an integer greater than or equal to 0. As described above, the lifespan τ is calculated by the lifespan calculator 174 for each type of information (for example, real time, quasi-real time, non-real time), so the number of transfers N is also calculated for each type of information. The transfer count calculator 178 outputs so that the correspondence between the type and the transfer count N can be understood. For example, the transfer count calculator 178 outputs a set of {information identifying the type, transfer count}.

The transfer processing time ΔT4 can be, for example, the same value as the processing time of the device itself. In that case, the average value of the time required for transfer processing of the received data in the past in the own device is stored in storage unit 182, and when calculating the number of times of transfer N, it is read from storage unit 182 and used. Just do it. A statistical value relating to the information transfer system may also be used as the transfer processing time ΔT4. For example, a server or the like collects information on the transfer processing time from each in-vehicle device, statistically processes it, calculates a representative value (average value, median value, etc.), and appropriately transmits it to the in-vehicle device. If the received representative value is stored in storage unit 182, the in-vehicle device can read the representative value from storage unit 182 and use it as transfer processing time ΔT4 when calculating the number of times N of transfers.

The determining unit 180 determines whether or not to transfer the data received by the packet receiving unit 170 from the number of transfers N input from the number of transfers calculating unit 178 . As described above, the transfer count N is calculated for each type of information, so if at least one of the input transfer counts N includes a value of 1 or more, the determining unit 180 determines to transfer. That is, the determination unit 180 determines not to transfer if the input number of times N of transfers is all 0. If the number of transfers is all 0, the data received at the transfer destination cannot be effectively used even if it is transferred. I will put it away. Therefore, if the number of times of transfer is all 0, no transfer is allowed, thereby suppressing an unnecessary increase in communication traffic.

When determining to transfer, the determination unit 180 outputs the transfer count N to the packet transmission unit 172 . For example, the determining unit 180 outputs the number of transfers of 1 or more among the number of transfers so that the correspondence between the type and the number of transfers N can be understood.

When the transfer count N is input from determination unit 180, packet transmission unit 172 reads the corresponding data from storage unit 182, adds the transfer count N to the read data, and transmits (transfers) the data. Since the transfer count N is calculated for each type of information, it is added so that the correspondence between the type and the transfer count N can be understood. The transfer at this time is performed by broadcasting. By adding the number of transfers to the transfer data and transmitting it, the vehicle-mounted device that has received the transfer data can easily determine whether or not to transfer again from the received number of transfers, as will be described later.

On the other hand, when the data is input from the life calculation unit 174, the determination unit 180 calculates a new transfer count by subtracting 1 from each transfer count included in the data. If the value above is included, it is determined to be transferred. That is, if all the new transfer counts are 0, the determination unit 180 determines not to transfer. This makes it possible to efficiently determine whether or not to transfer data. As will be described later as a first modified example, it is possible to receive the same data that has already been transferred, so it is preferable not to transfer the same data that has already been transferred when the same data is received again. As a result, it is possible to suppress an increase in communication traffic due to repeated transfer of the same data.

When determining to transfer, the determination unit 180 outputs a new number of times of transfer to the packet transmission unit 172 in the same manner as described above. As a result, the packet transmission unit 172 reads data corresponding to the new number of transfers input from the determination unit 180 from the storage unit 182, and adds the new number of transfers to the read data so that the correspondence with the type can be understood. and broadcast.

Any method may be used by the packet transmission unit 172 to identify data to be transferred corresponding to the number of transfers (or the new number of transfers) input from the determination unit 180 . For example, information specifying data to be transferred may be output from the determination unit 180 together with the number of transfers. The determination unit 180 can acquire information specifying data to be transferred (for example, data including generation time Tp) from the lifetime calculation unit 174 or the number of transfers calculation unit 178 .

As a result, when receiving data from an external device, the in-vehicle device 112 can efficiently determine whether or not to transfer the received data. Increased traffic can be suppressed. By acquiring the generation time of information from the source of information and pre-storing the allowable delay for each type of information, it is possible to efficiently calculate the lifetime of information for each type of information.

By considering not only the communication delay time but also the transfer processing time (estimated time required until the received data is transferred again), it is possible to accurately determine whether or not to transfer the information. Instead of calculating the number of transfers uniformly, the number of transfers is calculated according to the type of data, so it is possible to effectively use data (Even if it cannot be used as real-time information, it can be used as quasi-real-time or non-real-time information. It is possible to accurately determine whether or not to transfer the data while avoiding that the data is not transferred.

Note that the functions of the packet receiving unit 170 and the packet transmitting unit 172 are implemented by the communication unit 144 in FIG. The functions of the lifetime calculator 174, the communication delay estimator 176, the number of transfers calculator 178, and the determination unit 180 are implemented by the controller 148 and the memory 146 in FIG. The function of storage unit 182 is implemented by memory 146 . Each function of the in-vehicle device 112 may be implemented using dedicated hardware (circuit board, semiconductor integrated circuit (ASIC, etc.), etc.). For example, the functions of the life calculation unit 174, the communication delay estimation unit 176, the number of transfers calculation unit 178, and the determination unit 180 are realized by one or a plurality of semiconductor integrated circuits, and the control unit 148 and the memory 146 are separately configured as an in-vehicle device. 112 may be installed.

In the above description, a transfer count of 1 or more is transmitted and a transfer count of 0 is not transmitted, but a transfer count of 0 may be transmitted. If a transfer count of 0 is received, subtracting 1 will result in a negative value (-1), but the new transfer count should be set to 0. In addition, the number of times of transfer, which is 0, may be ignored in the in-vehicle device of the receiving destination.

[motion]
The operation of the in-vehicle device 112 will be described with reference to FIG. The processing shown in FIG. 5 is implemented by control unit 148 reading out a predetermined program from memory 146 and executing it.

At step 400, the control unit 148 determines whether or not data has been received. If it is determined that it has been received, control proceeds to step 402 . Otherwise control passes to step 420 .

At step 402, the control unit 148 determines whether the data received at step 400 includes data to be transferred (for example, sensor information). Specifically, if the received data includes information representing the time when the data (for example, sensor information) was generated (hereinafter simply referred to as generation time), the data is the data to be transferred. , and control proceeds to step 404 . Otherwise, control unit 148 determines that the data to be transferred is not included, and control proceeds to step 424 .

At step 404, control unit 148 determines whether the data received at step 400 includes the number of transfers. If so, control passes to step 422 . Otherwise control passes to step 406 . The transfer count received by the in-vehicle device 112 is the transfer count calculated in an in-vehicle device other than the in-vehicle device 112 (for example, the in-vehicle device 114 or 116).

At step 406 , the control unit 148 estimates the communication delay during transfer from the communication line speed, as described above regarding the communication delay estimating unit 176 . Control then passes to step 408 .

At step 408, the control unit 148 designates one type of information so as not to overlap. Control then passes to step 410 . The type of information is, as described above, a type classified according to the passage of time from the generation time of the data (sensor information, etc.). For example, one of real time, near real time and non-real time is specified.

In step 410 , control unit 148 calculates the life corresponding to the type specified in step 406 for the data (sensor information, etc.) received in step 400 as described above for life calculation unit 174 . Control then passes to step 412 .

At step 412 , the control unit 148 calculates the number of transfers corresponding to the type specified at step 406 as described above with respect to the transfer number calculation unit 178 . Control then passes to step 414 .

At step 414, the control unit 148 determines whether or not the number of transfers has been calculated for all types. If it is determined that the number of transfers for all types has been calculated, control proceeds to step 416 . Otherwise, control returns to step 408, where the not-yet-specified types are specified, and then steps 410 and 412 described above are performed.

At step 416, the control unit 148 determines whether or not the number of transfers calculated for each type in the above process is all zero. If it is determined to be all zeros, control passes to step 420 . Otherwise (at least one transfer count is greater than or equal to one), control passes to step 418 .

In step 418, the control unit 148 adds one or more transfer counts calculated in the above process and the corresponding type information to the data received in step 400, generates packet data, and transmits (transfers) the packet data. )do. Transmission is done by broadcasting.

At step 420, the control unit 148 determines whether or not an end instruction has been received. If it is determined that an end instruction has been received, this program ends. Otherwise control returns to step 400 . The end instruction is made, for example, by stopping the power supply to the in-vehicle device 112 (turning off the power).

On the other hand, if it is determined in step 404 that the number of transfers is included, in step 422 the control unit 148 determines the number of transfers for each type included in the data received in step 400, as described above with regard to the determination unit 180. Subtract 1 to calculate a new number of transfers. Control then passes to step 416 .

If it is determined in step 402 that the data is not the data to be transferred, in step 424 the control unit 148 executes processing according to the data received in step 400 . Control then passes to step 420 . For example, if the received data is the allowable delay ΔT1 or the representative value of the transfer processing time, the control unit 148 stores the received data in the memory 146 . As a result, the received data can be used in calculating the lifetime and the number of transfers.

As described above, when the in-vehicle device 112 receives data that does not include the number of times of transfer (data (such as sensor information) that was first transmitted from the data transmission source), the in-vehicle device 112 receives It is possible to determine whether or not the data can be effectively used when the data is transferred. When it is determined that the data cannot be used effectively, the in-vehicle device 112 does not transfer the received data, thereby suppressing an increase in communication traffic due to repeated transfer of information that cannot be used effectively.

Further, when data including the number of transfers is received, the new number of transfers obtained by decrementing the number of transfers by 1 is used to determine whether or not to transfer the received data. Yes, it can be determined efficiently.

(First modification)
Since the data to be transferred is broadcast, the transferred data may be received by a plurality of in-vehicle devices, and the plurality of in-vehicle devices may broadcast the same data. Therefore, there is a possibility that the same data as the data already received and transmitted by one in-vehicle device will be received again. A countermeasure against this is shown as a first modified example.

The information transfer system according to the first modification is configured in the same manner as in FIG. 1, and the in-vehicle devices 112, 114 and 116 are also configured as shown in FIGS. Therefore, the reference numerals shown in FIGS. 1, 2 and 4 are referred to accordingly.

The control unit 148 of the in-vehicle device 112 according to the first modified example executes the processing shown in FIG. 6 is obtained by adding step 500 between steps 418 and 420 and step 502 between steps 404 and 422 in the flowchart of FIG. In FIG. 6, processing of steps with the same numbers as in FIG. 5 is the same as the steps in FIG. Therefore, the different points will be mainly described without repeating redundant description.

If it is determined in step 404 that the data received in step 400 does not include the number of times of transfer, steps 406 to 418 are executed, and only data that can be effectively used when transferred is transferred in step 418. be done. Control then passes to step 500 .

At step 500 , control unit 148 stores information about the data transferred at step 418 in memory 146 . Control then passes to step 420 . Specifically, the control unit 148 stores information on the sender of the data transferred in step 418 (that is, the data received in step 400) in the memory 146 in association with the generation time of the data. Therefore, information on the transferred data is stored in memory 146 by repeating the processing from step 400 to step 418 .

On the other hand, if it is determined in step 404 that the number of transfers is included, control proceeds to step 502 . At step 502 , control unit 148 determines whether the data received at step 400 is the same as the data already transferred at step 418 . If so, the data received at step 400 is discarded and control passes to step 420 . Otherwise control passes to step 422 . Specifically, the control unit 148 converts the pair of the source address and data generation time included in the data (the header of the packet data) received in step 400 into the source address and data generation time stored in the memory 146. It is determined whether or not it is included in the set of generation times. Normally, since the data generation time in a specific device is uniquely determined, it is possible to determine whether or not the data is the same based on a set of the transmission source address specifying the device and the data generation time.

As a result, when the control unit 148 of the in-vehicle device 112 receives data that has already been transferred, it does not transfer the data even if it is data to be transferred and can be effectively used if transferred. On the other hand, if the received data is not the same as the already transferred data, in step 422, the control unit 148 subtracts 1 from the transfer count for each type included in the received data to obtain a new transfer count. Based on the result, it is determined whether or not transfer is necessary (step 416). Therefore, it is possible to suppress an increase in communication traffic caused by transferring the same data again.

Note that when data is generated by multitasking at a data transmission source, different data may be generated at the same time (represented by the same time information). In that case, the identity of the data can be determined using the information (task ID) for distinguishing the tasks in addition to the source address and the data generation time. For this purpose, the data transmission source device further attaches the task ID to the data transmission, and the control unit 148 of the in-vehicle device 112, in step 500, {transmission source address, data generation time, task ID} are stored in the memory 146, and in step 502, it is determined whether or not the set of {source address, data generation time, task ID} is stored in the memory 146 or not.

(Second modification)
It is also effective to adjust the directivity of the transmission radio wave to prevent the same information from being redundantly transferred to the vehicle-mounted device to which it has already been transferred. In the second modification, the directivity of transmission radio waves is controlled when information is transferred.

An information transfer system according to the second modification is configured in the same manner as in FIG. The in-vehicle devices 112, 114 and 116 are configured as shown in FIGS. However, the communication unit 144 shown in FIG. 2 has a function of adjusting the directivity of transmission radio waves for wireless communication (for example, beam forming) and a function of acquiring information from GPS (Global Positioning System). Reference numerals shown in FIGS. 1, 2 and 4 will be referred to below as appropriate.

The control unit 148 of the in-vehicle device 112 according to the second modified example executes the processing shown in FIG. The flowchart of FIG. 7 is obtained by adding steps 510 and 512 between steps 416 and 418 in the flowchart of FIG. In FIG. 7, processing of steps with the same numbers as in FIG. 5 is the same as the steps in FIG. Therefore, the different points will be mainly described without repeating redundant description.

If it is determined in step 416 that at least one transfer count is greater than or equal to 1, then in step 510 control unit 148 identifies the current direction of travel of vehicle 102 . Since the control unit 148 can acquire the current position (position coordinates) of the vehicle 102 from the GPS via the communication unit 144, the position coordinates of the vehicle 102 acquired at different times and the times at which each position coordinate was acquired can be used. , the running direction (running vector) of the vehicle 102 is calculated. Control then passes to step 512 . The running direction of the vehicle 102 may be appropriately calculated by another program executed in parallel with this program and stored in the memory 146 . In that case, control unit 148 may read the current traveling direction of vehicle 102 from memory 146 .

At step 512, the control unit 148 sets the directivity of the antenna used for transmission by the communication unit 144 so that the intensity of the transmitted radio wave is strong in the direction opposite to the traveling direction of the vehicle 102 specified at step 510 (rear of the vehicle 102). Adjust so that After that, the control moves to step 418, in which the control unit 148 adds the transfer count and type information to the data received in step 400, and transmits the data.

As a result, the transferred data is received only by the in-vehicle device or the like positioned behind the vehicle 102 and is not received by the in-vehicle device positioned in the driving direction of the vehicle 102 . For example, in FIG. 1, data transferred from on-board device 112 of vehicle 102 is received by on-board device 114 of vehicle 104 traveling behind vehicle 102, but is received by on-board device 114 of vehicle 104 traveling behind vehicle 102. It is not received by the in-vehicle device 116 of 106 . Similarly, the in-vehicle device 114 that has received the data transferred by the in-vehicle device 112 adjusts the directivity of the transmission antenna so that the transmission radio wave is stronger behind the vehicle 104 when transferring the data. Therefore, it is possible to reduce the possibility that the same information is redundantly transferred to the in-vehicle device that has already been transferred.

In the above description, when information including the number of transfers is received, the number of transfers is reduced without calculating the life of the information, and whether or not to transfer is determined according to the result. not. Even when information including the number of transfers is received, the lifetime and the number of transfers may be newly calculated. That is, in the flowchart shown in FIG. 5, steps 404 and 422 may be deleted. In this case, the control unit 148 in FIG. 2 executes the processing from step 406 to step 416 without determining whether the received data includes the number of transfers, calculates the life and the number of transfers, and calculates the number of transfers. It is determined whether or not to transfer according to the

In the above description, the information types are real-time, near-real-time, and non-real-time, and the allowable delay is set to 1 second, 1 minute, and 5 days, respectively, but the present invention is not limited to this. The permissible delay may be another value as long as it can be classified so that appropriate processing is performed on the information according to the passage of time from the generation time of the information. Moreover, the types other than these may be used. The number of types should be two or more. For example, if the sensor information intended to be transferred is used as short-term driving assistance information and is not used for statistical processing, etc., the life span of the information for the two types of real-time and near-real-time should be calculated.

Alternatively, the data transmission source may specify the type of information intended to be transferred, and transmit the information. For example, when sensor information is transferred with the intention of being used for real-time driving support, when the sender first sends the sensor information, it adds information indicating the type (type information) and sends it. do it. In that case, in FIG. 5, the processing from step 408 to step 414 is not repeated, and the life may be calculated using the allowable delay corresponding to the received type information. Also, since the number of transfers calculated is one, when information is transmitted in step 418, only one number of transfers should be added and transmitted, and the type information need not be added.

In the above description, the case of determining whether or not the received data is data to be transferred is determined based on whether or not the data generation time is included in the received data, but the present invention is not limited to this. For example, broadcasted data may be determined to be forwarded. Also, a transfer instruction may be specified. If a transfer instruction is added to data intended to be transferred, it can be determined whether or not the data is transfer target data based on the presence or absence of the instruction.

Although the case where information is transferred only between in-vehicle devices has been described above, the present invention is not limited to this. A subject that transfers information may be the server 124 in FIG. 1 or a device (computer or the like) installed on the roadside. That is, these fixedly installed devices may receive the information transmitted from the in-vehicle device and execute the processing shown in FIG.

Although the present invention has been described above by describing the embodiments, the above-described embodiments are examples, and the present invention is not limited only to the above-described embodiments. The scope of the present invention is indicated by each claim in the scope of claims after taking into account the description of the detailed description of the invention, and all changes within the meaning and range of equivalents to the wording described therein include.

100 Information Transfer Systems 102, 104, 106 Vehicles 112, 114, 116 In-Vehicle Device 120 Infrastructure Sensor 122 Base Station 124 Server 126 Network 128 Detection Target 140 Sensor 142 I/F Sections 144, 164 Communication Sections 146, 162 Memories 148, 160 Control Units 150, 166 Bus 170 Packet receiver 172 Packet transmitter 174 Lifetime calculator 176 Communication delay estimator 178 Transfer frequency calculator 180 Judgment unit 182 Storage unit 400, 402, 404, 406, 408, 410, 412, 414, 416 , 418, 420, 422, 424, 500, 502, 510, 512 steps

Claims (10)

an acquisition unit that acquires information;
a lifespan calculation unit that calculates the lifespan of the information acquired by the acquisition unit;
a determination unit that determines whether or not to transfer the information according to the delay time and the lifetime associated with the information transfer process;
A transmission unit that transmits the information in response to the determination by the determination unit that the information is to be transferred,
the lifetime represents the time that the information can be used,
The acquisition unit acquires additional information including at least generation time information representing a time at which the information was generated,
The lifespan calculation unit calculates a transmission delay, which is the time from the time represented by the generation time information to the time when the information is acquired by the acquisition unit, from an allowable delay time predetermined for each type of real-time information. calculating the life span for each of the types by subtracting the time;
The determination unit is
determining an integer value of 0 or more obtained by dividing the life calculated for each type by the delay time as the number of transfers for each type;
An information transfer device that determines to transfer the information if at least one transfer count among the transfer counts for each of the types is 1 or more. The delay time includes communication delay time and transfer processing time,
The communication delay time is a predicted value of the time from when the information is transferred from the information transfer device to when it is acquired by an external device,
2. The information transfer device according to claim 1 , wherein said transfer processing time is a predicted value of the time required for said external device to transfer said information after obtaining it. 3. The information transfer apparatus according to claim 1 , wherein said transmission unit transmits said at least one number of times of transfer which is 1 or more together with said information. The determination unit is
In response to the fact that the acquisition unit acquires the number of times of transfer for each type representing the number of times the transfer of the information is permitted together with the information, a subtraction unit that determines a value obtained by subtracting 1 from the number of transfers as a new number of transfers for each type;
4. The method according to any one of claims 1 to 3 , wherein if at least one new transfer count among the new transfer counts for each type determined by the subtraction unit is 1 or more, it is determined that the information is to be transferred. The information transfer device according to item 1. The determination unit is
In response to the fact that the acquisition unit acquires the number of times of transfer for each type representing the number of times the transfer of the information is permitted together with the information, the information is including a same data determination unit that determines whether the information is the same as the information transmitted from the transmission unit before acquiring the information;
3. The same data determination unit determines not to transfer the information after determining that the information is the same as the information transmitted from the transmission unit before acquiring the information. The information transfer device according to any one of claims 1 to 3 . An in-vehicle device mounted in a vehicle,
an acquisition unit that acquires information by wireless communication;
a lifespan calculation unit that calculates the lifespan of the information acquired by the acquisition unit;
a determination unit that determines whether or not to transfer the information according to the delay time and the lifetime associated with the transfer processing of the information by the wireless communication;
A transmission unit that transmits the information by the wireless communication in response to the determination by the determination unit that the transfer is to be performed,
the lifetime represents the time that the information can be used,
The acquisition unit acquires additional information including at least generation time information representing a time at which the information was generated,
The lifespan calculation unit calculates a transmission delay, which is the time from the time represented by the generation time information to the time when the information is acquired by the acquisition unit, from an allowable delay time predetermined for each type of real-time information. calculating the life span for each of the types by subtracting the time;
The determination unit is
determining an integer value of 0 or more obtained by dividing the life calculated for each type by the delay time as the number of transfers for each type;
An in-vehicle device that determines to transfer the information if at least one of the numbers of transfers for each type is 1 or more. The transmission unit includes a directivity setting unit that sets the directivity of the transmission radio wave for the wireless communication,
7. The in-vehicle device according to claim 6 , wherein said directivity setting unit sets said directivity such that said information transmitted from said transmitting unit is transmitted in a direction opposite to a running direction of said vehicle. including a first information transfer device and a second information transfer device that communicate with each other;
The first information transfer device is
a first acquisition unit that acquires information;
a lifespan calculation unit that calculates the lifespan of the information acquired by the first acquisition unit;
a first determination unit that determines whether or not to transfer the information according to a delay time associated with transfer processing of the information to the second information transfer device and the life;
a first transmission unit that transmits the information and the number of times of transfer that indicates the number of times that the transfer of the information is permitted in response to the determination by the first determination unit that the transfer is to be performed;
the lifetime represents the time that the information can be used,
The first acquisition unit acquires additional information including at least generation time information representing a time at which the information was generated,
The lifespan calculation unit calculates the time from the time represented by the generation time information to the time when the information is acquired by the first acquisition unit from the allowable delay time predetermined for each type of real-time nature of the information. calculating the lifetime for each of the types by subtracting the transmission delay time;
The first determination unit
determining an integer value of 0 or more obtained by dividing the life calculated for each type by the delay time as the number of transfers for each type;
determining that the information is to be transferred if at least one transfer count among the transfer counts for each type is 1 or more;
The second information transfer device is
a second acquisition unit that acquires the information transmitted from the first information transfer device;
a subtraction unit for determining, as a new transfer count, a value obtained by subtracting 1 from the transfer count in response to the fact that the second acquisition unit has acquired the transfer count together with the information;
a second determination unit that determines whether to transfer the information based on the new number of transfers determined by the subtraction unit;
and a second transmission unit configured to transmit the information and the new number of transfers other than 0 in response to the second determination unit determining to transfer. an obtaining step for obtaining information;
a lifespan calculation step of calculating a lifespan of the information acquired by the acquisition step;
a determination step of determining whether or not to transfer the information according to the delay time accompanying the transfer processing of the information and the life;
and a transmission step of transmitting the information in response to the fact that it is determined to be transferred by the determination step,
the lifetime represents the time that the information can be used,
The obtaining step obtains additional information including generation time information representing at least the time when the information was generated;
In the life calculation step, the transmission delay is the time from the time represented by the generation time information to the time when the information is acquired in the acquisition step, from an allowable delay time predetermined for each type of real-time information. calculating the life span for each of the types by subtracting the time;
The determination step includes
determining an integer value of 0 or more obtained by dividing the life calculated for each type by the delay time as the number of transfers for each type;
The information transfer method , wherein if at least one transfer count among the transfer counts for each of the types is 1 or more, it is determined that the information is to be transferred. to the computer,
an acquisition function for acquiring information;
a lifespan calculation function for calculating the lifespan of the information acquired by the acquisition function;
a judgment function for judging whether or not to transfer the information according to the delay time accompanying the transfer processing of the information and the life;
A computer program for realizing a transmission function for transmitting the information in response to the fact that the determination function determines that the information should be transferred,
the lifetime represents the time that the information can be used,
The acquisition function acquires additional information including at least generation time information representing a time at which the information was generated;
The lifespan calculation function calculates a transmission delay, which is the time from the time represented by the generation time information to the time when the information is acquired by the acquisition function, from an allowable delay time predetermined for each type of real-time information. calculating the life span for each of the types by subtracting the time;
The determination function is
determining an integer value of 0 or more obtained by dividing the life calculated for each type by the delay time as the number of transfers for each type;
A computer program that determines to transfer the information if at least one of the numbers of transfers for each type is 1 or more.

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