Communication system for local edge networks

Abstract

To provide a local edge network communication system equipped with a mobile base station and multiple moving bodies, which can be applied to automatic driving of vehicles, or the like.SOLUTION: In a local edge network communication system 1, a mobile base station 10 and multiple moving bodies 20 (vehicle 21, drone 22, mobile robot 23, portable device 24, bicycle 25, or the like) are connected with one another via a common wireless interface, the multiple moving bodies have a sensor 20a, and further there are multiple data hierarchies for sharing sensor information obtained by the sensor between the mobile base station and the multiple moving bodies. The sensor information is divided into different data hierarchies according to the characteristics and stored. According to the characteristics of the stored data, data operation conditions including the communication method and the data sharing area are set for each data hierarchy.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a communication system for a local edge network.

Background Art

[0002] In recent years, safe driving and autonomous driving support of vehicles have been put into practical use, and the development of autonomous driving has also been progressing. In these systems, for example, high-precision map information required for the system is distributed from the cloud to the vehicle via a communication base station, and thus it is realized as a communication system that combines in-vehicle computer and communication.

[0003] As such a communication system, for example, a communication system equipped with both a wide-area communication unit and a narrow-area communication unit has been proposed (see Japanese Unexamined Patent Application Publication No. 2020-5029). In this communication system, by mounting two communication units, the reliability of vehicle-to-vehicle communication is improved.

[0004] On the other hand, since vehicle information is sequentially broadcast from each of the two communication modules of the wide-area communication unit and the narrow-area communication unit, heat generation and an increase in current consumption are likely to occur. In the above communication system, when there is no possibility of encountering other vehicles based on an instruction from a radio base station, this problem is solved by suspending the wide-area periodic transmission process to suppress heat generation and current consumption.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the safe driving, automated driving support, or automated driving of a vehicle, for example, in the static map data for car navigation that was collected, edited, and distributed once every few months to several years by a data collection dedicated vehicle, data called a dynamic map is used, which superimposes information such as surrounding vehicle, pedestrian, and signal information, accident information, and traffic control information that changes sequentially and is necessary for highly safe driving support and automated driving on the static map data.

[0007] In the automated driving of a vehicle, etc., control is mainly performed based on information in the vicinity of the vehicle. Therefore, the information that changes sequentially in the above dynamic map is often data in a relatively narrow local area. Also, in order to obtain a more accurate, that is, a dynamic map with a large amount of information, a method of expanding the data by sharing the information acquired by a moving body moving in a local area with other moving bodies is effective.

[0008] In the dynamic data obtained in this way, since there is a lot of information that changes sequentially, in the above conventional communication system, the amount of information to be broadcast may become extremely large, which may deteriorate the communication environment such as an increase in communication delay. Also, assuming that the communication time will be long in advance, information in a range wider than necessary will be transmitted, and there may be a waste of communication such as including information that is not used and the information being old when received. Also, as the types of information to be handled increase, the period during which the transmission process can be paused tends to become shorter, so there is a risk that the effect of suppressing heat generation and current consumption will also decrease. For this reason, a more efficient data communication system is desired.

[0009] The present invention has been made based on the above circumstances, and an object thereof is to provide a communication system for a local edge network that can efficiently handle high-precision dynamic data necessary for the automated driving of a vehicle, etc.

Means for Solving the Problem

[0010] A communication system for a local edge network according to an aspect of the present invention is a communication system for a local edge network including a mobile base station and a plurality of mobile bodies, wherein the mobile base station and the plurality of mobile bodies are connected to each other by a common wireless interface, the plurality of mobile bodies have sensors, and the communication system further includes a plurality of data layers for sharing sensor information acquired by the sensors among the mobile base station and the plurality of mobile bodies. The sensor information is stored separately in different data layers according to the characteristics of the data, and data operation conditions including a communication method and a data sharing area are set for each data layer according to the characteristics of the data stored therein.

Advantages of the Invention

[0011] The communication system for a local edge network of the present invention can efficiently handle high-precision dynamic data required for automatic driving of vehicles and the like.

Brief Description of the Drawings

[0012]

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Embodiments for Carrying Out the Invention

[0013] [Description of Embodiments of the Present Invention] First, embodiments of the present invention will be listed and described.

[0014] A communication system for a local edge network according to an aspect of the present invention is a communication system for a local edge network including a mobile base station and a plurality of mobile bodies, wherein the mobile base station and the plurality of mobile bodies are connected to each other by a common wireless interface, the plurality of mobile bodies have sensors, and further includes a plurality of data layers for sharing sensor information acquired by the sensors among the mobile base station and the plurality of mobile bodies, the sensor information is divided and stored in different data layers according to the characteristics of the data, and data operation conditions including a communication method and a data sharing area are set in units of the data layers according to the characteristics of the data stored in each.

[0015] In the communication system for the local edge network, the information is stored in different data layers according to the characteristics of the data of the sensor information acquired by the plurality of mobile bodies. And since the operation conditions are determined according to the characteristics of the data stored in each data layer unit, the communication system for the local edge network can efficiently handle a huge amount of data.

[0016] The mobile body may include a vehicle. The communication system for the local edge network can be particularly preferably used for a system including a vehicle.

[0017] The mobile body may further include a drone, a mobile robot, or both. By further including a drone, a mobile robot, or both in the mobile body in this way, it is easy to improve the accuracy of dynamic data.

[0018] The above plurality of data layers may preferably consist of four data layers: a first layer where the characteristics of the above data are static, a second layer where they are quasi-static, a third layer where they are quasi-dynamic, and a fourth layer where they are dynamic. The average update time interval during which the data changes becomes shorter in the order of static, quasi-static, quasi-dynamic, and dynamic. That is, the frequency of data change is high in this order. By configuring the data layers according to the frequency of data change in this way, the accuracy and operation efficiency of dynamic data can be improved.

[0019] The above data operation conditions include an allowable delay time and an allowable data transfer amount per transmission. The allowable delay time is preferably set such that the value increases in the order from the first layer to the fourth layer, and the allowable data transfer amount is preferably set such that the value decreases in the order from the first layer to the fourth layer. By setting the allowable delay time in this way, data updates are appropriately performed according to the data update frequency. Also, by setting the allowable data transfer amount as described above, it is possible to suppress the increase in communication volume due to the high data update frequency, and thus suppress the decrease in the operation efficiency of dynamic data. Here, the "allowable delay time" refers to the end-to-end time from the time when the transmission data is observed by the sensor (taken as the reference time) until the transmission is completed, and it is not necessary to start the transmission exactly at the reference time. For example, when the allowable delay time is 100 seconds, the actual data transmission may be performed between 90 seconds and 100 seconds.

[0020] In determining the above data operation conditions, the radio wave propagation environment and the communication environment are used. The radio wave propagation environment preferably includes the propagation distance between the moving body that acquired the above sensor information, and the other moving bodies and the mobile base station. The communication environment preferably includes available frequencies, transmission bands, and transmission speeds. By using the above radio wave propagation environment and communication environment in determining the data operation conditions in this way, it is easy to maintain the communication quality.

[0021] [Details of Embodiments of the Present Invention] Hereinafter, a communication system for a local edge network according to an embodiment of the present invention will be described with appropriate reference to the drawings.

[0022] The communication system 1 for a local edge network shown in FIG. 1 is a communication system for a local edge network including a mobile base station 10 and a plurality of mobile bodies 20. Further, the communication system 1 for the local edge network includes a roadside unit 30.

[0023] The mobile base station 10, the plurality of mobile bodies 20, and the roadside unit 30 are connected by a wireless interface. As the wireless interface, 5G, local 5G, 4G, DSRC (Dedicated Short Range Communications), LPWA (Low Power Wide Area), WiFi, an interface of the IEEE802.11 series, etc. can be used.

[0024] Further, the mobile base station 10 and the plurality of mobile bodies 20 are connected by a common wireless interface to each other. That is, the mobile base station 10 and the plurality of mobile bodies 20 can directly communicate with any two of them. Further, for example, communication using one or a plurality of mobile bodies 20 as a repeater, such as vehicle 21 - drone 22 - mobile base station 10, can also be performed. In FIG. 1, in order to avoid complication of the drawing, a part of the communication between the two is shown as a representative, and not all of them are shown.

[0025] FIG. 2 shows an example of a network configuration using the communication system 1 for the local edge network. In the above network configuration, a plurality of the communication systems 1 for the local edge network are installed according to the geographical range (data sharing area) where the wireless communication can be performed, and a wide area is covered.

[0026] In the above network configuration, first, in the communication system 1 for the local edge network, sensors of the mobile body 20 described later acquire information, and the information is processed by the mobile body 20 and stored in the end database of the mobile body 20. A part of the above information, that is, information about which mobile body acquired what kind of information, is collected by the local base station 12 (described later) included in the mobile base station 10 together with the information acquired by the roadside unit 30. After all the collected information is processed by the local base station 12, it is further collected and processed by the main base station 11 described later, and with the main base station 11 as a gateway (GW), the necessary information is relayed to the cloud X as appropriate.

[0027] Cloud X has a router X1, a server X2, and a data center X3. Cloud X collects information from the mobile base stations 10 in each data sharing area via the router X1. The server X2 manages the collected information, and the data center X3 has a database (main database) and stores the above information under the control of the server X2. Note that the information stored in the data center X3 is the necessary information among the information collected and processed by the mobile base station 10. Not all data is necessarily stored.

[0028] In the above network configuration, the communication system 1 for the local edge network may be configured for each use case. That is, for the same geographical range, a plurality of the communication systems 1 for the local edge network may be installed and used separately according to purposes such as for MaaS (Mobility as a Service), for agriculture, and for industry.

[0029] <Mobile base station> The mobile base station 10 is a base station that encompasses and controls the geographical range in which wireless communication of the communication system 1 for the local edge network can be performed. Specifically, the mobile base station 10 performs, for example, data management processing and distribution control processing of data to be shared by a plurality of mobile bodies 20.

[0030] The mobile base station 10 includes a main base station 11 and a local base station 12, and can communicate with other mobile base stations 10 of the communication system 1 for the local edge network or with the cloud X, constituting the backbone network of the communication.

[0031] (Main base station) The main base station 11 oversees and controls the entire geographical area. The main base station 11 has a communication function, a database, and a processor. Additionally, the main base station 11 may have sensors. By having sensors in this way, the information obtained by the main base station 11 can be used as dynamic data.

[0032] (Local base station) The local base station 12 belongs to the lower layer of the main base station 11 and subdivides and oversees the geographical area overseen by the main base station 11. Therefore, usually, a plurality of local base stations 12 are provided. Conversely, if there is no need to subdivide the above geographical area, the local base station 12 can be omitted, and the mobile base station 10 is composed of only the main base station 11, directly overseeing the entire geographical area.

[0033] The local base station 12 has a communication function, a database, and a processor. Additionally, the local base station 12 may have sensors. By having sensors in this way, the information obtained by the local base station 12 can be used as dynamic data. The local base station 12 can be, for example, a local 5G base station.

[0034] <Mobile entity> A plurality of mobile entities 20 are devices that move within the data sharing area (geographical area where wireless communication is possible) managed by the communication system 1 for the local edge network.

[0035] The plurality of moving objects 20 may include a vehicle 21, a drone 22, a mobile robot 23, a portable device 24, a bicycle 25, and the like. Among these, it is preferable that the moving object 20 includes the vehicle 21. The communication system 1 for the local edge network can be particularly preferably used in a system including the vehicle 21, for example, a V2X communication system used in an autonomous driving or MaaS business. "V2X" is an abbreviation for Vehicle to X, and is a technology that collectively refers to the connection and mutual cooperation between the vehicle 21 and something (other vehicles 21, pedestrians, infrastructure, network, etc.). This V2X is essential for, for example, the autonomous driving of the vehicle 21. In the above V2X communication system, it is necessary to handle time-series data having a large dynamic range in terms of time and space acquired by the vehicle 21. The communication system 1 for the local edge network can handle such time-series data particularly efficiently. Hereinafter, the description will be made on the premise that the moving object 20 includes the vehicle 21, but it does not mean that the communication system 1 for the local edge network regards the vehicle 21 as an essential component as the moving object 20.

[0036] The moving object 20 may further include the drone 22, the mobile robot 23, or both. By further including a drone, a mobile robot, or both in the moving object 20 in this way, it is easy to improve the accuracy of dynamic data.

[0037] The plurality of moving objects 20 have a communication function, a database (terminal database), a processor, and a sensor 20a. Note that the "sensor" refers to an element or device that detects a phenomenon in the real world and replaces the detected phenomenon with a signal that can be processed by a computer. In FIG. 1, a configuration in which the drone 22 has a sensor 20a is illustrated, but for other moving objects 20, although not illustrated, they similarly have a sensor 20a.

[0038] The mobile bodies 20 are interconnected, and the information collected by their respective sensors 20a is processed by the above processor and stored in the above database. Examples of the above information include any natural phenomena such as weather and temperature, phenomena occurring in artificial objects such as traffic jams, human vital information such as heart rate, respiratory rate, and blood pressure, approach of people to vehicles, and information on fallen objects on the road, which can be detected by sensors. In the communication system 1 for the local edge network, for example, camera images taken by a mobile robot 23, map data for driving, imaging data taken by a drone 22, and 3D shape data generated therefrom are assumed.

[0039] <Roadside unit> The roadside unit 30 is a device installed on the road for controlling and monitoring vehicle 21 traffic. The roadside unit 30 includes traffic lights, street lights, etc., and is connected to the local base station 12 through the above wireless interface.

[0040] The roadside unit 30 has a communication function. Also, it is preferable that the roadside unit 30 has a database (terminal database), a processor, and sensors. By having these configurations, the information acquired by the roadside unit 30 can be used as dynamic data.

[0041] Also, the roadside unit 30 may have a function as a mobile base station 10. That is, the roadside unit 30 can function as a mobile body 20 that does not move, a mobile base station 10, or both.

[0042] <Hierarchical database> The databases of the main base station 11, local base station 12, multiple mobile bodies 20, and roadside unit 30 of the communication system 1 for the local edge network, together with the database of the data center X3 of the cloud X, constitute a hierarchical database 100 as shown in FIG. 4.

[0043] The hierarchical database 100 has a main database 101 and a plurality of terminal databases 103 that are directly or indirectly connected to the main database 101 via one or more intermediate databases 102. Databases at the terminals such as the plurality of mobile bodies 20 and roadside units 30 (having no lower hierarchy) constitute the terminal databases 103. Databases such as the main base station 11 and local base station 12 located at positions relaying the information of the terminal database 103 to the cloud X constitute the intermediate databases 102. The database of the data center X3 where all information is aggregated constitutes the main database 101. Further, the terminal database 103 has a corresponding sensor (for example, the sensor 20a of the mobile body 20). In this way, the hierarchical database 100 has a flexible change in the database structure, ease of search, and a distributed adaptation arrangement suitable for distributed storage. Note that, for example, a configuration in which the intermediate database has a multi-layer structure can also be adopted, such as arranging an intermediate database in the roadside unit 30 that aggregates its own data and further relays the information of the terminal database of the mobile body 20.

[0044] The hierarchical database 100 shown in FIG. 3 has a terminal master table 103a shared among a plurality of mobile bodies 20 in the terminal database 103 arranged in the mobile body 20. This terminal master table 103a is shared by the intermediate master table 102a of the intermediate database 102 and the main master table 101a of the main database 101. Information (database ID) of databases directly connected above and below a specific database, for example, is stored in these master tables, and by using this master table, flexible addition, modification, and deletion of databases can be performed. The above master table is managed so as to be shared by all the databases included in the hierarchical database 100 by the main database 101 of the data center X3.

[0045] The master tables (main master table 101a, intermediate master table 102a, and terminal master table 103a) may have the following functions. (1) Perform labeling (road link) that links the data to roads, and update, add, or delete the master table for each road link and for each new piece of data, so that the data table storing the data collected within the data sharing area of the mobile base station 10 can be referenced. (2) Have data (for example, the position and speed of the vehicle 21, the data held by the vehicle 21) that is necessary when the mobile base station 10 plans a distribution control procedure for transmitting and receiving the contents of the data table between the mobile base station 10 and the vehicle 21 or for transmitting and receiving between the vehicles 21. With these functions, the mobile base station 10 can efficiently perform data management processing and distribution control processing simultaneously.

[0046] This data needs to be constantly shared between the vehicle 21 existing within the data sharing area of the mobile base station 10 and the mobile base station 10. Although the data volume is small, the update frequency is high. Therefore, as the transmission and reception channel, it is advisable to use a communication control channel (for example, C-Plane).

[0047] Also, the terminal database 103 can store, for example, the sensor information acquired by the sensor 20a in the terminal actual data table 103b. This data may be sequentially replicated and transferred to a higher-level database and aggregated in the main database 101. However, in the intermediate database 102 and the main database 101, a reference data table (intermediate reference data table 102b and main reference data table 101b) having a search path leading to the registered data in the terminal actual data table 103b and a reference value grouped by classification information related to the above registered data can be configured. By providing the reference data table, the three layers of the main database 101, the intermediate database 102, and the terminal database 103 can be coordinated, and when searching for registered data, the necessary data can be provided to the user as one virtual database. In other words, by enabling the information of the registered data distributed and stored in the hierarchical database 100 to be handled in a single database collectively, it becomes possible to speed up the search and reduce the storage capacity.

[0048] In addition, for storing data in the hierarchical database 100, transferring data, monitoring search traffic, optimizing the arrangement of the hierarchical database 100, and setting a communication path with a communication partner, for example, open source software can be used.

[0049] <Data Hierarchy> The communication system 1 for the local edge network further includes a plurality of data hierarchies for sharing sensor information acquired by sensors among the mobile base station 10 and the plurality of mobile bodies 20. The sensors include at least the sensors of the plurality of mobile bodies 20. Further, when the main base station 11, the local base station 12, and the roadside unit 30 have sensors, the sensors may include some or all of these.

[0050] The sensor information is stored separately in the different data hierarchies according to the characteristics of the data. Specifically, databases possessed by a plurality of mobile bodies 20 and the like have a plurality of data hierarchies, and each data is stored in a specific data hierarchy according to its type.

[0051] In addition, the communication system 1 for the local edge network sets data operation conditions including a communication method and a data sharing area in units of the data hierarchy according to the characteristics of the data stored therein.

[0052] Examples of the data operation conditions include the communication method adopted in the wireless interface, the method of processing the data by the processor, the database for storing the data, the geographical range for sharing the data, and the like. Among them, the method of processing data is preferable, and it is more preferable that the data operation conditions include an allowable delay time, which is a type of data processing method, and an allowable data transfer amount per time.

[0053] In determining the above data operation conditions, the radio wave propagation environment, communication environment, energy consumption, quality requirements including delay and transmission errors, energy consumption, security requirements, charging requirements, data update cycle, etc. between the vehicle 21 and the communication partner in the local edge network communication system 1 can be used.

[0054] Among them, it is preferable to use the radio wave propagation environment and the communication environment in determining the above data operation conditions. Further, the above radio wave propagation environment preferably includes the propagation distance between the moving body 20 that has acquired the above sensor information and other moving bodies 20 and the mobile base station 10, and the above communication environment preferably includes available frequencies, transmission bands, and transmission speeds. By using the above radio wave propagation environment and communication environment in determining the data operation conditions in this way, it is easy to maintain the communication quality.

[0055] The above plurality of data layers preferably consists of four data layers: a first layer in which the characteristics of the above data are static, a second layer in which they are quasi-static, a third layer in which they are quasi-dynamic, and a fourth layer in which they are dynamic. The average update time interval at which the data changes becomes shorter in the order of static, quasi-static, quasi-dynamic, and dynamic. That is, the frequency of data change is high in this order. By configuring the data layers according to the frequency of data change in this way, the accuracy and operation efficiency of dynamic data can be improved.

[0056] Here, the characteristics of the data being "static", "quasi-static", "quasi-dynamic", and "dynamic" mean the magnitude of the average time interval during which the data changes. The more static the data, the larger the average time interval, and the more dynamic the data, the smaller the average time interval. The average time interval between adjacent indicators (i.e., for example, between "static" and "quasi-static") generally differs by a factor of 10 or more. Specifically, for example, the average time interval of "dynamic" data is 1 second (the response time of a person from environmental recognition to a change in driving operation), the average time interval of "quasi-dynamic" data is 10 seconds (the time to pass through one road link), the average time interval of "quasi-static" data is 2 to 3 minutes (the time to pass through the range of one mobile base station 10 (the lowest-layer local base station 12)), and the average time interval of "static" data can be 1 hour (the time of one trip from the start to the end of the movement of the moving body 20).

[0057] The first layer handles large-capacity static data with a large allowable data transfer volume (e.g., about 100 MB), a long allowable delay time (e.g., about 1000 seconds), and a low communication frequency (e.g., about once every 10 days). For this first layer, the processing of data acquired by a plurality of moving bodies 20, the storage of data in the database, and the distribution of data are performed from the cloud X. The communication method is a broadband V2N (vehicle 21 to network), aiming to share data of a plurality of moving bodies 20 in a wide area (e.g., an area unit with a radius of about 120 km). As a method for sharing data with the cloud X, for example, the MQTT protocol can be used. First, data is aggregated from a plurality of moving bodies 20, etc. via the mobile base station 10 to the cloud X (the data is stored in the main database of the cloud X), and then the data is distributed to a plurality of moving bodies 20 via the mobile base station 10. The purpose of information sharing in the first layer between the mobile base station 10 and a plurality of moving bodies 20 includes, for example, route design for car navigation. Examples of the above data include road structure information, lane and road surface information acquired by sensors possessed by the vehicle 21 and the roadside unit 30, and dedicated data collection vehicles (drones 22 and mobile robots 23).

[0058] On one hand, the fourth layer, which is the counter electrode to the first layer, handles small-capacity dynamic data with a small allowable data transfer volume (e.g., less than about 100 B), a short allowable delay time (e.g., about 1 second), and a high communication frequency (e.g., about 10 times per second). For this fourth layer, the processing of data acquired by a plurality of moving bodies 20, the storage of data in a database, and the distribution of data are performed from the moving bodies 20. The communication method is narrow-band V2V (vehicle 21 to vehicle 21), and data sharing among a plurality of moving bodies 20 is achieved in a narrow area (e.g., a regional unit at the town and village level with a radius of about 15 km). Also, by shortening the delay time through V2V and localizing the data, the energy consumption required for communication can be localized and reduced. As a method for sharing data among a plurality of moving bodies 20, a data flooding method in which data is transmitted to a plurality of moving bodies 20 can be used. The moving body 20 that has acquired the data sequentially propagates the data to the moving bodies 20 in its vicinity, so that the data gradually spreads to a plurality of moving bodies 20. The purposes of information sharing in the first layer between the mobile base station 10 and a plurality of moving bodies 20 include, for example, autonomous driving and advanced driving assistance. Examples of the above data include prediction information (proximity vehicles, pedestrians, signal movements, etc.) acquired by sensors of the vehicle 21 and the roadside unit 30 and processed by processors of each moving body 20 and roadside unit 30. The prediction information handled by the fourth layer has a large amount of information collected by the moving body 20, a short lifespan, and is used at the location where the data is acquired. In such cases, it is possible to reduce the energy consumption required for communication by using the data only within the data sharing area rather than via the cloud X.

[0059] The second layer handles quasi-bulk quasi-static data with an allowable data transfer volume smaller than that of the first layer (e.g., about 10 MB or more and less than 100 MB), an allowable delay time shorter than that of the first layer (e.g., about 100 seconds or more and less than 1 hour), and a communication frequency higher than that of the first layer (e.g., about once a day). For this second layer, the processing of data acquired by a plurality of mobile bodies 20, the storage of data in the database, and the distribution of data may be performed either by the cloud X or the mobile bodies 20. The communication method combines wideband V2N and narrowband V2V to share data of a plurality of mobile bodies 20 in a medium area (e.g., a regional unit at the prefecture level with a radius of about 50 km). The purpose of information sharing in the second layer between the mobile base station 10 and the plurality of mobile bodies 20 includes, for example, the construction of advance information for route change. Examples of the data include road regulation information, construction and traffic jam information, and wide-area weather information acquired by sensors of the vehicle 21 and the roadside unit 30 and dedicated data collection vehicles (drone 22 and mobile robot 23).

[0060] The third layer handles quasi-small-capacity quasi-dynamic data with an allowable data transfer volume in a range smaller than that of the second layer and larger than that of the fourth layer (e.g., about 100 B or more and less than 10 MB), an allowable delay time in a range larger than that of the second layer and smaller than that of the fourth layer (about 1 second or more and less than 100 seconds), and a communication frequency higher than that of the fourth layer and lower than that of the second layer (e.g., about once per second). For this third layer, the processing of data acquired by a plurality of mobile bodies 20, the storage of data in the database, and the distribution of data may be performed either by the cloud X or the mobile bodies 20. The communication method combines narrowband V2V and wideband V2N to share data of a plurality of mobile bodies 20 in a medium area (e.g., a regional unit from the coverage range of the mobile base station 10 with a radius of about 1 km to an area bundling a plurality of base stations with a radius of about 100 km). The purposes of information sharing in the third layer between the mobile base station 10 and the plurality of mobile bodies 20 include stop measures during driving and the construction of advance information for lane change. Examples of the data include the presence of accidents, obstacles, and breakdown vehicles, road congestion, and narrow-area weather information acquired by sensors of the vehicle 21 and the roadside unit 30.

[0061] The features of each of the above layers are summarized in Tables 1 and 2. Note that the allowable delay time and the allowable data transfer amount are described as typical values representing each layer.

[0062]

[0075]

Table 1

[0063]

Table 2

[0064] As shown in Table 1, for example, map data collected and processed by a dedicated data collection vehicle for car navigation and distributed every few days or months is shared with a delay of several hours to several days. Information necessary for autonomous driving collected and processed by, for example, a general vehicle 21 can be shared with a delay of less than 1 second. The above map data has a large data transfer amount, but since the allowable delay time is large, sharing with a delay of several hours to several days is allowed. Therefore, it is also possible to perform data transfer at a timing when the network load is light, and the network load can be equalized. In other words, the period with a high network load can be reduced.

[0065] As in the above example, in the communication system 1 for the local edge network, it is preferable that the allowable delay time is set such that the allowable values increase in order from the first layer to the fourth layer, and the allowable data transfer amount is set such that the allowable values decrease in order from the first layer to the fourth layer. That is, the set allowable delay time is larger for the second layer than for the first layer, larger for the third layer than for the second layer, and larger for the fourth layer than for the third layer. Conversely, the set allowable data transfer amount is smaller for the second layer than for the first layer, smaller for the third layer than for the second layer, and smaller for the fourth layer than for the third layer. By setting the allowable delay time in this way, data updates are appropriately performed according to the data update frequency. Also, by setting the allowable data transfer amount as described above, it is possible to suppress the increase in the communication volume due to the high data update frequency, so it is possible to suppress the decrease in the operation efficiency of dynamic data.

[0066] FIG. 4 and FIG. 5 show examples of the geographical arrangement of the hierarchical database 100. As shown in FIG. 4, the terminal database 103 handles information at the municipality level within the range where the mobile body 20 moves daily, for example, within a radius of about 15 km. Also, as shown in FIG. 5, the intermediate database 102 handles information at the prefecture level with a radius of about 50 km, and the main database 101 handles information at the level of, for example, the Kanto region and the Kansai region with a radius of about 120 km. Each piece of information is shared by a plurality of mobile bodies 20.

[0067] FIG. 6 shows a configuration example of the mobile base station 10 corresponding to the road network. In FIG. 6, a road map within a data sharing area, for example, within a radius of about 15 km, by the terminal database 103 is shown. In FIG. 6, A1 to A6, a0 to a5, etc. indicate the branch positions of a single continuous road. At the branch positions, different labelings are given with respect to the direction in which the road extends, so different labels are assigned to the same branch position, for example, A1 and a0. Note that in FIG. 6, the labeling of some branch positions is omitted.

[0068] When the mobile body 20 at point P in FIG. 6 transmits data to the mobile body 20 at point Q, whether to use the line of V2N2V (L1, L2) via the mobile base station 10 or directly use the V2V (L3) line is selected by comparing the radio wave propagation conditions, the bandwidth of the available communication line, and the frequency. Note that the positions of point P and point Q are represented by the distance from the node. That is, for point P, it can be represented, for example, by the distance from a1 which is a node. Note that when using V2V without using V2N2V, the resources of the unused V2N2V (communication between the mobile base station 10 and the mobile body 20) can be used for communication between the mobile base station 10 and another terminal. Furthermore, in many cases, that communication becomes a more efficient communication partner as seen from the mobile base station 10, so an effect of increasing the communication capacity within the area of the mobile base station 10 can be expected.

[0069] FIG. 7 is an example of the configuration of data used for data transfer between the mobile bodies 20. In FIG. 7, the road link names are managed by the main master table 101a in the main database 101 and are expanded to the intermediate master table 102a and the terminal master table 103a. In each road link, the difference before and after a certain time (update time) becomes the content of the data (hereinafter, also referred to as "difference data"). For example, in FIG. 7, the content of the data = on-road obstacle means that there was no on-road obstacle before the time of time1 which is the update time, while there is an on-road obstacle after the time of time1. The terminal actual data table 103b, the intermediate reference data table 102b, and the main reference data table 101b store this update item, the mobile body 20 that performed the update (which may also be a mobile base station 10 or the like), the vehicle position and speed of the mobile body 20, the ID (not shown) of the terminal database 103 where the data is stored, etc., and form a tree structure as the entire hierarchical database 100 in terms of road links, time series, database configuration, etc.

[0070] The terminal actual data table 103b can have the following characteristics. (1) Dynamic, quasi-dynamic, quasi-static, and static data generated in the road link are stored by data hierarchy. (2) All of the data generated in the road link or all of the difference data are stored. (3) For example, based on a 1 km square area of one mobile base station 10, an independent ID is assigned to one direction or both directions of the road with the section from road branch to road branch as one unit. (4) For example, several mobile base stations 10 can be grouped into one terminal actual data table 103b. Thereby, the entire area covered by one map can also be covered.

[0071] FIG. 8 shows an example of the configuration of the vehicle 21 that can realize the data transfer of FIG. 7. The vehicle 21 includes a sensor 20a, a terminal database 103, a measurement unit 21a, an operation condition 21b, an environment measurement unit 21c, an edge AI 21d, a communication protocol control unit 21e, and an antenna 21f.

[0072] The measurement unit 21a measures the position coordinates, vehicle speed, and current time of the vehicle 21. For example, a high-precision GPS can be used for the measurement by the measurement unit 21a. The operation condition 21b is a condition for specifying the hierarchy for storing the data collected by the sensor 20a, and information such as that shown in Table 1 and Table 2 is stored therein. The environment measurement unit 21c measures the radio wave propagation environment and communication environment of the vehicle 21. The edge AI 21d performs data processing. The communication protocol control unit 21e selects and controls the communication method of the vehicle 21. The antenna 21f transmits and receives radio waves for communication between the vehicle 21 and other moving bodies 20 and the like.

[0073] In the vehicle 21 shown in FIG. 8, for the data obtained by combining the sensor information collected by the sensor 20a and the information on the position coordinates, vehicle speed, and current time measured by the measurement unit 21a, the edge AI 21d sets the data structure within the data sharing area and extracts the differential data based on the operation condition 21b. This differential data is used to identify the additional data hierarchy and is stored in the terminal database 103. Further, the edge AI 21d extracts by comparing the data required by the vehicle 21 with the data held by the own vehicle 21, and based on the information of the vehicle 21 that holds the required data or the mobile base station 10 that holds it and the operation condition 21b, information regarding the required delay, quality requirements including transmission errors, security requirements, charging requirements, update cycle, etc. is sent to the communication protocol control unit 21e. The communication protocol control unit 21e acquires information on the radio wave propagation environment (propagation possible distance) and communication environment from the environment measurement unit 21c, selects and switches the communication method (for example, the difference between V2N and V2X), and communicates with other moving bodies 20 and the like via the antenna 21f.

[0074] <Advantages> In the communication system 1 for the local edge network, the information is stored in different data hierarchies according to the characteristics of the data of the sensor information acquired by the plurality of moving bodies 20. And since the operation conditions are determined according to the characteristics of the data stored in each data hierarchy unit, the communication system 1 for the local edge network can efficiently handle a huge amount of data.

[0075] [Other Embodiments] The above embodiments do not limit the configuration of the present invention. Therefore, based on the description in this specification and common technical knowledge, omission, substitution, or addition of the constituent elements of each part of the above embodiments is possible, and all of them should be construed as belonging to the scope of the present invention.

[0076] In the above embodiments, it has been described that it is preferable that a plurality of data layers consist of four data layers where the characteristics of the data are static, quasi-static, quasi-dynamic, and dynamic. However, it is also possible to use a plurality of data layers for the characteristics of one data. For example, the third layer where the characteristics of the data are quasi-dynamic may be two data layers: the coverage range of the mobile base station 10 with a radius of about 1 km and the area formed by bundling a plurality of base stations with a radius of about 100 km.

[0077] In the above embodiments, the case where the communication system for the local edge network includes a roadside unit has been described. However, a configuration without a roadside unit is also within the scope intended by the present invention.

Industrial Applicability

[0078] As described above, the communication system for the local edge network of the present invention can efficiently handle high-precision dynamic data required for automatic driving of vehicles and the like.

Explanation of Reference Numerals

[0079] 1 Communication system for local edge network 10 Mobile base station 11 Main base station 12 Local base station 20 Moving body 20a Sensor 21 Vehicle 21a Measuring unit 21b Operating conditions 21c Environment measuring unit 21d Edge AI 21e Communication protocol control unit 21f Antenna 22 Drone 23 Mobile robot 24 Portable device 25 Bicycle 30 Roadside unit 100 Hierarchical database 101 Main database 101a Main master table 101b Main reference data table 102 Intermediate database 102a Intermediate master table 102b Intermediate reference data table 103 Terminal database 103a Terminal master table 103b Terminal actual data table X Cloud X1 Router X2 Server X3 Data center

Claims

1. A communication system for a local edge network comprising a mobile base station and a plurality of mobile units, the mobile base station and the plurality of moving objects are connected to each other by a common wireless interface; the plurality of moving bodies each having a sensor and a database; The database further includes a plurality of data layers for sharing sensor information acquired by the sensors between the mobile base station and the plurality of moving objects; storing the sensor information in different data layers according to characteristics of the data by a method of distributing data to the plurality of mobile objects via the mobile base station or a data flooding method of transmitting data to the plurality of mobile objects; A communication system for a local edge network in which data operation conditions including a communication method and a data sharing area are set for each data layer according to the characteristics of the data stored therein.

2. 2. The communication system for a local edge network according to claim 1, wherein the moving object includes a vehicle.

3. The communication system for a local edge network according to claim 2 , wherein the moving object further includes a drone, a mobile robot, or both.

4. 4. The communication system for a local edge network according to claim 2 or 3, wherein the plurality of data hierarchies consist of four data hierarchies, namely, a first layer in which the characteristics of the data are static, a second layer in which the characteristics of the data are quasi-static, a third layer in which the characteristics of the data are quasi-dynamic, and a fourth layer in which the characteristics of the data are dynamic.

5. the data operation conditions include an allowable delay time and an allowable data transfer amount per transfer, The allowable delay time is set so that the allowable value increases in the order from the first layer to the fourth layer, 5. The communication system for a local edge network according to claim 4, wherein the allowable data transfer rates are set so that the allowable values decrease in the order from the first layer to the fourth layer.

6. The radio wave propagation environment and communication environment are used to determine the data operation conditions, the radio wave propagation environment includes a propagation distance between the mobile body that acquired the sensor information and another mobile body and the mobile base station; 6. The communication system for a local edge network according to claim 1, wherein the communication environment includes available frequencies, transmission bands, and transmission speeds.

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