Communication environment evaluation device, communication environment evaluation system, and communication environment evaluation method

Abstract

The communication environment evaluation device (10) is characterized by comprising an information acquisition unit that acquires received data of communication packets of a plurality of applications transmitted between an on-board wireless communication device (3) installed in a vehicle (2) and a ground wireless communication device (8) installed on the ground, an application identification unit that identifies the applications, and an evaluation unit that analyzes the received data of the identified applications and evaluates changes in the communication environment for each application.

Description

[Technical field]

[0001] The present disclosure relates to a communication environment evaluation device, a communication environment evaluation system, and a communication environment evaluation method for evaluating a communication environment for wireless communication between on-board a train and ground. [Background technology]

[0002] 3GPP (registered trademark) (3rd Generation Partnership Project), a standardization organization for mobile communication systems, is considering fifth-generation (hereinafter sometimes referred to as "5G") wireless access systems. Currently, mobile communication systems used in railway operation are often built as private networks designed, constructed, and managed by railway operators, but it is expected that 5G systems will also be used for wireless communication between on-board and ground stations in the railway field.

[0003] In Japan, 5G commercial services have been gradually provided by telecommunications carriers since around 2020. Local 5G is also being institutionalized as a mechanism for local companies, local governments, etc. to build spot 5G networks in their own buildings or on their premises. Compared to conventional communication systems, 5G systems have features such as high speed, large capacity, low latency, high reliability, and multiple simultaneous connections. Taking advantage of these features, for example, in the railway field, an increase in new applications is expected, such as autonomous driving, train control, and on-board video surveillance.

[0004] In a wireless communication system, since the communication quality changes over time, it is important to grasp the current communication quality for stable operation of the system. For example, Patent Document 1 proposes a method for evaluating the communication environment for each communication path in a system in which multiple types of communication paths are available. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2022 / 219730 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the above conventional technology, even when data of multiple applications are transmitted over one communication path, the communication environment is evaluated for each communication path, so that it is not possible to evaluate the communication environment for each application. Since the design requirements and performance requirements that are the premise of each application are different, it is important to evaluate the communication environment for each application and manage the communication quality.

[0007] The present disclosure has been made in consideration of the above, and has an object to provide a communication environment assessment device capable of assessing a communication environment for each application. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems and achieve the object, the communication environment evaluation device according to the present disclosure includes an information acquisition unit that acquires reception data of communication packets of a plurality of applications transmitted between an on-board wireless communication device installed in a vehicle and a ground wireless communication device installed on the ground, an application identification unit that identifies the application of the communication packets based on the reception data, a feature calculation unit that calculates the reception intervals of the communication packets and calculates a distribution of the reception intervals, and an evaluation unit that analyzes the distribution of the reception intervals of the communication packets of the identified applications and evaluates a change in the communication environment for each application. a storage unit that accumulates the evaluation results of the evaluation unit, and a display unit that displays, for each time period and for each section in which the vehicle is located, an application for which the evaluation results accumulated in the storage unit are to be displayed, vehicle conditions of a vehicle in which an on-board wireless communication device that transmits communication packets is installed, and operating conditions of the vehicle; The present invention is characterized by comprising: Effect of the Invention

[0009] The communication environment assessment device according to the present disclosure has an effect of being able to assess the communication environment for each application. [Brief description of the drawings]

[0010] [Figure 1]FIG. 1 is a diagram showing a configuration example of a communication environment evaluation system according to a first embodiment. [Diagram 2] FIG. 2 is a diagram showing an example of a functional configuration of the communication environment evaluation device shown in FIG. 1; [Diagram 3] FIG. 3 is a diagram showing an example of received data acquired by an information acquisition unit shown in FIG. 2; [Figure 4] FIG. 3 is a diagram showing an example of data classification by the application identification unit shown in FIG. 2; [Diagram 5] FIG. 3 is an explanatory diagram of an example of the operation of the feature amount calculation unit shown in FIG. 2; [Figure 6] FIG. 3 is a diagram showing an example of data stored in the feature DB shown in FIG. 2. [Figure 7] A flowchart for explaining a learning process for generating a trained model. [Figure 8] Diagram of how trained models are generated [Figure 9] An explanatory diagram of the operation of the evaluation unit shown in FIG. [Figure 10] A flowchart for explaining an evaluation process for evaluating a communication environment [Figure 11] FIG. 3 is a diagram showing an example of a display screen output by the display unit shown in FIG. 2; [Figure 12] FIG. 1 shows an example of the configuration of a communication environment evaluation system according to a second embodiment. [Figure 13] FIG. 13 is a diagram illustrating the functions of the data aggregation device of FIG. [Figure 14] FIG. 13 is a diagram showing an example of received data acquired by the communication environment evaluation device shown in FIG. 12. [Figure 15] A flowchart for explaining a learning process in the second embodiment. [Figure 16] FIG. 13 is an explanatory diagram of a calculation process of a reception interval of communication packets in the third embodiment; [Figure 17] Flowchart for explaining the learning process in the third embodiment [Figure 18] FIG. 13 is an explanatory diagram of a learning process in the third embodiment. [Figure 19] FIG. 13 is a diagram showing a configuration example of a communication environment evaluation system according to a fourth embodiment. [Figure 20]FIG. 13 is a diagram showing a configuration example of a communication environment evaluation system according to a modification of the fourth embodiment. [Figure 21] FIG. 13 is a diagram showing a configuration example of a communication environment evaluation system according to a fifth embodiment. [Figure 22] FIG. 13 is a diagram showing a configuration example of a communication environment evaluation system according to a modification of the fifth embodiment. [Figure 23] FIG. 1 shows an example of the hardware configuration of a communication environment evaluation device according to the first to fifth embodiments and a data aggregating device according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A communication environment assessment device, a communication environment assessment system, and a communication environment assessment method according to embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0012] Embodiment 1 Fig. 1 is a diagram showing an example of the configuration of a communication environment evaluation system 1 according to a first embodiment. The communication environment evaluation system 1 includes an on-board wireless communication device 3 and an on-board terminal 4 mounted on a train car 2, and a base station 5, a core network device 6, a connection router 7, a ground wireless communication device 8, and a communication environment evaluation device 10 installed on the ground. A plurality of applications represented by app #1 to app #n share a wireless section for ground-to-vehicle communication. Data is transmitted at different periods for each application.

[0013] For example, a communication packet transmitted by the on-board wireless communication device 3 is transmitted to the ground wireless communication device 8 via the on-board terminal 4, the base station 5, the core network device 6 and the connection router 7. The communication environment assessment device 10 acquires received data, which is data of the communication packets received by the ground wireless communication device 8 from the on-board wireless communication device 3 as described above, and evaluates the communication environment for each application. The communication environment assessment device 10 may be placed on a cloud.

[0014] Fig. 2 is a diagram showing an example of a functional configuration of the communication environment assessment device 10 shown in Fig. 1. The communication environment assessment device 10 has an information acquisition unit 11, an application identification unit 12, a feature amount calculation unit 13, a feature amount DB (DataBase) 14, an assessment unit 15, a storage unit 16, and a display unit 17.

[0015] The information acquiring unit 11 extracts received data which is information on a communication packet received by the ground wireless communication device 8. The information acquiring unit 11 may acquire, as the received data, not only data included in the received communication packet but also data related to the received communication packet, for example, data such as a reception time generated when the ground wireless communication device 8 receives a communication packet, and data acquired from inside or outside the communication environment evaluation system 1 based on the data included in the received communication packet.

[0016] FIG. 3 is a diagram showing an example of the received data acquired by the information acquisition unit 11 shown in FIG. 2. The received data shown in FIG. 3 includes an application type, which is information for identifying the type of application, a time zone, a reception time, and an acquisition date, which indicate the time when the communication packet was received, and a vehicle position, a vehicle condition, and an operation condition, which are vehicle information. The application type is, for example, data included in the received communication packet, and is, for example, information such as a protocol, a port number, and a data length. The time zone is a time range representing the reception time, and is, for example, information given by the information acquisition unit 11 based on the information of the reception time given by the ground wireless communication device 8. In the example of FIG. 3, the vehicle position includes a section and position information. The vehicle position may be included in the received communication packet, or the vehicle 2 may be identified from the information included in the communication packet, and the position information of the vehicle 2 may be acquired from a train operation management system (not shown) or the like. The section is a position range representing the vehicle position, and is, for example, information given by the information acquisition unit 11 based on the acquired vehicle position.

[0017] The vehicle conditions are, for example, information such as the vehicle type and the vehicle antenna installation position. The antenna installation position may be, for example, information indicating whether the antenna is installed indoors or outdoors. The operation conditions are, for example, information such as the line section and traveling direction, which are vehicle operation information. The traveling direction may be, for example, information indicating whether the direction is uphill or downhill. The information acquisition unit 11 outputs the acquired received data to the application identification unit 12.

[0018] Returning to the description of FIG. 2, the application identification unit 12 classifies the communication packets for each application based on the received data acquired by the information acquisition unit 11. The application identification unit 12 identifies the application based on the information of the application type acquired by the information acquisition unit 11, and classifies the received data for each application. The application identification method may be a method based on a protocol, a port number, a data length, or the like. For example, when the information of the application type acquired by the information acquisition unit 11 corresponds one-to-one with the application, the application identification unit 12 can identify the application for each value of the application type. Alternatively, the application identification unit 12 may identify the application by a combination of multiple types of information. Furthermore, the application identification unit 12 can classify the received data based on the received data acquired by the information acquisition unit 11. For example, the application identification unit 12 can classify the received data by a time period, a section, a vehicle condition, and an operating condition. The application identification unit 12 classifies the received data for each combination of, for example, a time period, a section, a vehicle condition, and an operating condition. The application identification unit 12 outputs the received data to the feature calculation unit 13 in association with the identified application and classification information.

[0019] Fig. 4 is a diagram showing an example of data classification by the application identification unit 12 shown in Fig. 2. In the example shown in Fig. 4, the application identification unit 12 classifies the received data based on the application type, the time period indicating the time when the communication packet was received, the reception time and acquisition date, the section and location information indicating the vehicle location, the vehicle conditions, and the operating conditions.

[0020] The feature calculation unit 13 calculates a feature indicating a feature of a communication packet for each classification by the application identification unit 12. Specifically, the feature calculation unit 13 can calculate a reception interval from a difference in reception time of the communication packets, and calculate a probability density function (PDF) of the reception interval as a feature. In addition to the probability density function of the reception interval, the feature may be a packet loss rate calculated from a sequence number per unit time, or a receiving side throughput calculated from the data amount of the received communication packets.

[0021] FIG. 5 is an explanatory diagram of an example of the operation of the feature amount calculation unit 13 shown in FIG. 2. As shown in FIG. 5, the feature amount calculation unit 13 calculates the reception interval at the ground wireless communication device 8 of the communication packet transmitted from the on-board wireless communication device 3 to the ground wireless communication device 8 via the wireless section. In FIG. 5, the packet reception interval of the application #k is calculated. In the middle diagram of FIG. 5, the horizontal axis indicates the packet number, and the vertical axis indicates the reception interval of the communication packet of the packet number. Here, since the packet number is incremented every time a communication packet is received, the communication packet with the largest packet number is the communication packet that was received most recently. The feature amount calculation unit 13 calculates the probability density function of the reception interval for each specific section based on the calculated reception interval. The section used when calculating the PDF is called the PDF calculation section, as shown in FIG. 5.

[0022] Although there is some fluctuation in the reception intervals of communication packets, there is a tendency for the distribution to be concentrated at a specific value depending on the transmission cycle of the application. The fluctuation in the reception intervals of communication packets increases when the radio wave environment or traffic environment deteriorates and packet loss occurs in the wireless section. The communication environment can be evaluated by analyzing the change in the fluctuation in the reception interval for each application using the PDF of the reception interval as a feature.

[0023] However, if the communication packets are received on different dates or if the data is received in a subsequent vehicle 2 on the bus schedule, the reception interval will be long. Also, in an application that transmits many packets at once because there is a large amount of traffic and data is divided into multiple communication packets for transmission, the reception interval may become short regardless of the transmission cycle of the application. For this reason, it is desirable to exclude data with reception intervals that are not subject to the above-mentioned analysis from the analysis.

[0024] Returning to the explanation of FIG. 2, the feature DB 14 is a database that accumulates the feature calculated by the feature calculation unit 13. The feature DB 14 stores feature for each combination of application type, time period when a communication packet is received, section, vehicle conditions, and operating conditions. The feature DB 14 also accumulates learned models. The feature DB 14 accumulates feature and learned models for each application type and for each classification that combines time period, section, vehicle conditions, and operating conditions. Note that the feature DB 14 only stores data when communication is being performed normally, and does not store data when an abnormality occurs in communication.

[0025] Fig. 6 is a diagram showing an example of data stored in the feature DB 14 shown in Fig. 2. Fig. 6 shows an example in which a probability density function (PDF) of a reception interval is stored as a feature. A feature is stored for each application represented by application #1 to application #n. The feature and the learned model are associated with each classification by the application identification unit 12.

[0026] The trained model is generated by having a learning device learn the data stored in the feature DB 14. At this time, the learning device may be provided in the feature DB 14, or the feature DB 14 and the learning device may be provided separately.

[0027] 7 is a flowchart for explaining a learning process for generating a trained model. The information acquisition unit 11 acquires reception data of a communication packet received by the ground wireless communication device 8 (step S101).

[0028] The application identification unit 12 classifies the received data of the communication packets for each application (step S102). The application identification unit 12 also classifies the received data based on the contents of the received data, such as the time period, the section, the vehicle conditions, and the operating conditions (step S103).

[0029] The feature calculation unit 13 calculates the feature of the communication packet for each classification by the application identification unit 12 (step S104). The feature calculation unit 13 accumulates data of the calculated feature in the feature DB 14 (step S105). The feature DB 14 causes a learning device to learn the accumulated data and generates a learned model (step S106). The feature DB 14 stores the generated learned model in association with the feature data. The learned model is for obtaining an evaluation result from the feature. The learning device may be provided in the feature DB 14, or the feature DB 14 and the learning device may be provided separately.

[0030] The information on the features and the trained model stored in the feature DB 14 may be stored in advance in the feature DB 14. In this case, the learning flow can be omitted.

[0031] FIG. 8 is an explanatory diagram of the generation of a trained model. The feature DB 14 generates a trained model for outputting an evaluation result of a communication environment from features by using data accumulated in the feature DB 14. As shown in FIG. 8, the data accumulated in the feature DB 14 are features accumulated for each application and for each classification based on the value of the received data. In FIG. 8, the packet reception interval is accumulated as a feature for each combination of time period, section, vehicle condition, and operating condition. In each of the multiple graphs in the upper diagram of FIG. 8, the horizontal axis is the reception interval of communication packets, the vertical axis of the bar graph is the number of data, and the vertical axis of the line graph is PDF.

[0032] The accumulated data as described above is input to a learning device, and a trained model is generated for each application and for each classification based on the value of the received data. The trained model thus generated is stored for each application and for each of the above classifications.

[0033] Here, a case where kNN (k-Nearest Neighbor), which is a clustering method, is applied will be described. Since kNN is a method for analyzing data to be evaluated using learning data, unlike other machine learning algorithms, there is no processing such as parameter adjustment in the learning phase, and when kNN is used, the processing for generating the trained model described above refers to a processing for classifying and storing the learning data. Specifically, the learning device acquires feature amounts when the communication environment is normal as learning data, and classifies and stores the data by application type, time period when the data was acquired, section, vehicle conditions, and operating conditions.

[0034] Returning to the description of Fig. 2, the evaluation unit 15 has a function of analyzing received data of communication packets and evaluating changes in the communication environment for each application. Specifically, the evaluation unit 15 can evaluate the communication environment using the features calculated by the feature calculation unit 13 and the trained model stored in the feature DB 14.

[0035] Fig. 9 is an explanatory diagram of the operation of the evaluation unit 15 shown in Fig. 2. The evaluation unit 15 queries the feature DB 14 for a trained model under the same conditions, using as input conditions the type of application of the received data to be evaluated, the time period in which the data was acquired, the section, the vehicle conditions, and the operating conditions. The feature DB 14 returns a trained model under the same conditions as the input conditions as a response to the evaluation unit 15. The evaluation unit 15 inputs features into a trained model that matches the input conditions, and obtains an evaluation result that is output.

[0036] The evaluation result may be, for example, a risk level. In kNN, k pieces of neighborhood data for the data to be evaluated are extracted from the learning data, and the distance between the data to be evaluated and the neighborhood data is calculated. That is, when the evaluation unit 15 inputs the feature amount of the evaluation target to the trained model, the distance is output as the evaluation result. The trained model is trained only on data when the communication environment is normal, and this distance is the difference between the learning data, which is the feature amount in the normal state, and the feature amount of the data to be evaluated, so it can be used as a risk level indicating the difference from the normal state. Therefore, it can be confirmed that the larger the risk level, the larger the change from the normal communication environment in the data to be evaluated.

[0037] In this embodiment, the evaluation unit 15 has been described as outputting an evaluation result of the communication environment using a trained model trained by a learning device contained in the feature DB 14, but it may also be configured to acquire a trained model from outside and output an evaluation result based on this trained model.

[0038] In this manner, the evaluation unit 15 can output to the display unit 16 the evaluation result obtained based on the feature amount of the communication packet.

[0039] In this embodiment, the case where kNN is applied to the learning algorithm has been described, but the present invention is not limited to this. As for the learning algorithm, reinforcement learning, supervised learning, unsupervised learning, semi-supervised learning, etc. can also be applied.

[0040] In addition, the learning algorithm used by the learning device may be deep learning that learns to extract the feature amounts themselves, or other known methods.

[0041] Furthermore, the clustering method is not limited to the above kNN, and may be any known clustering method, such as non-hierarchical clustering using the K-means method or hierarchical clustering using the shortest distance method.

[0042] Furthermore, the functions of the learning device and the evaluation unit 15 may be, for example, a device connected to the communication environment evaluation device 10 via a network, and separate from the communication environment evaluation device 10. Furthermore, the functions of the learning device and the evaluation unit 15 may exist on a cloud server. Furthermore, the learning data may be feature amounts acquired by another communication environment evaluation device 10 as long as the conditions, such as the application used, are the same.

[0043] 10 is a flow chart for explaining the evaluation process for evaluating the communication environment. The information acquisition unit 11 acquires reception data of a communication packet received by the ground wireless communication device 8 (step S201).

[0044] The application identification unit 12 classifies the received data of the communication packets for each application (step S202). The application identification unit 12 also classifies the received data based on the contents of the received data, such as the time period, the section, the vehicle conditions, and the operating conditions (step S203).

[0045] The feature amount calculation unit 13 calculates the feature amount of the communication packet for each classification by the application identification unit 12 (step S204).

[0046] Next, the evaluation unit 15 queries the feature DB 14 to acquire a trained model under the same conditions as the received data to be evaluated (step S205).

[0047] The evaluation unit 15 evaluates the communication environment using the acquired trained model (step S206). The display unit 17 displays the evaluation result on the display screen (step S207).

[0048] Returning to the description of Fig. 2, the storage unit 16 accumulates the evaluation results of the evaluation unit 15. The display unit 17 displays the evaluation results accumulated in the storage unit 16 on a display screen. The storage unit 16 accumulates the generated evaluation results every time an evaluation result is generated. Furthermore, the display unit 17 updates the display contents every time the evaluation result is updated.

[0049] Fig. 11 is a diagram showing an example of a display screen output by the display unit 17 shown in Fig. 2. The display unit 17 displays the risk level, which is the evaluation result, for each application and for each combination of vehicle conditions and driving conditions. Fig. 11 shows an example of a display screen output by the display unit 17 shown in Fig. 2. k , operating conditions O k The horizontal axis of FIG. 11 represents the interval, and the vertical axis represents the time period. n The risk level for each of the time periods T1 to T n Each of these can be expressed by the color or pattern used to fill in each square. In the example in Figure 11, the pattern used to fill in each square changes depending on the risk level.

[0050] As described above, the communication environment assessment device 10 according to the first embodiment is characterized by including an information acquisition unit 11 that acquires reception data of communication packets of a plurality of applications transmitted between the on-board wireless communication device 3 installed in the vehicle 2 and the ground wireless communication device 8 installed on the ground, an application identification unit 12 that identifies the application of the communication packets, and an evaluation unit 15 that analyzes the reception data of the identified application and evaluates the change in the communication environment for each application. With such a configuration, it becomes possible to evaluate the change in the communication environment for each type of application from the reception data of the received communication packets.

[0051] The importance of changes in the communication environment and responses to changes in the communication environment differ depending on the application. For example, even if the communication environment of an application for displaying advertisements to passengers in vehicle 2 deteriorates, the advertisements will simply not be displayed for a certain period of time, so there is little impact on the operation of vehicle 2. However, if the communication environment of an application for the autonomous driving of vehicle 2 deteriorates, this may develop into a situation that may endanger human life. Therefore, for example, when the communication environment begins to deteriorate, responses can be taken such as stopping vehicle 2 in a safe place or stopping communication of less important applications other than autonomous driving before a communication failure occurs.

[0052] Moreover, the communication environment assessment device 10 further includes a feature amount calculation unit 13 that calculates a feature amount indicating a feature of a communication packet from the received data, and the assessment unit 15 can also analyze the communication packet based on the feature amount calculated by the feature amount calculation unit 13. The feature amount may be any value corresponding to the communication quality, and may be, for example, the reception interval of the communication packet, the packet loss rate, or the receiving side throughput.

[0053] The communication environment evaluation device 10 may further include a feature DB 14 that accumulates the feature calculated by the feature calculation unit 13 for each classification based on the received data. The "classification" is determined, for example, by a combination of application type, time period, section, vehicle condition, and operating condition. In the above embodiment, the classification is determined using all of the application type, time period, section, vehicle condition, and operating condition, but the classification can be determined based on at least one of the application type, time period, section, vehicle condition, and operating condition. The feature DB 14 may also store a trained model for outputting the evaluation result of the communication environment from the feature for each of the above classifications. This allows the evaluation unit 15 to acquire a trained model corresponding to the above classification of the received data of the communication packet acquired by the information acquisition unit 11 from the feature DB 14, and to evaluate the communication environment using the feature of the communication packet and the acquired trained model.

[0054] The communication environment evaluation device 10 may further include a storage unit 16 that accumulates the evaluation results of the evaluation unit 15, and a display unit 17 that displays the evaluation results on a display screen for each classification based on the received data, based on the evaluation results accumulated in the storage unit 16. As shown in Fig. 11 for example, the display unit 17 can display the evaluation results for each time period and for each section in which the vehicle 2 is located, regarding the application for which the evaluation results are to be displayed, the vehicle conditions of the vehicle 2 in which the on-board wireless communication device 3 that transmits communication packets is installed, and the operating conditions of the vehicle 2.

[0055] In the first embodiment, the communication environment assessment device 10 is installed on the ground. The information acquisition unit 11 acquires reception data of communication packets transmitted by the on-board wireless communication device 3 and received by the ground wireless communication device 8. Since the ground wireless communication device 8 receives communication packets from the on-board wireless communication devices 3 of multiple vehicles 2, the communication environment assessment device 10 acquires reception data of communication packets between the multiple on-board wireless communication devices 3 and the ground wireless communication device 8.

[0056] The received data includes information included in the communication packet, information generated with the transmission of the communication packet, information about the device of the source or destination of the communication packet, etc. For example, the information acquisition unit 11 can acquire received data including at least one of information indicating the type of application, information indicating the reception time of the communication packet, and vehicle information indicating the characteristics of the vehicle 2 in which the on-board wireless communication device 3 that transmits the communication packet is installed. The application identification unit 12 classifies the communication packet based on the above received data. This makes it possible to identify the time and section in which a change in the communication environment occurs.

[0057] The vehicle information is information including at least one of the position information of the vehicle 2, the vehicle conditions of the vehicle 2, and the operating conditions of the vehicle 2. The vehicle conditions are, for example, information such as the vehicle type and the antenna installation position of the vehicle 2. The antenna installation position may be, for example, information indicating whether the antenna is installed indoors or outdoors. The operating conditions are, for example, information such as the line section and traveling direction, which are operating information of the vehicle 2. The traveling direction may be, for example, information indicating whether it is an uphill direction or a downhill direction.

[0058] Moreover, according to the first embodiment, it is possible to provide a communication environment evaluation system 1. This communication environment evaluation system 1 is a communication environment evaluation system 1 that evaluates the communication environment of communication packets of a plurality of applications transmitted between an on-board wireless communication device 3 installed in a vehicle 2 and a ground wireless communication device 8 installed on the ground, and is characterized in that it includes a communication environment evaluation device 10 having an information acquisition unit 11 that acquires reception data of communication packets of a plurality of applications transmitted between the on-board wireless communication device 3 and the ground wireless communication device 8, an application identification unit 12 that identifies the application of the communication packets, and an evaluation unit 15 that analyzes the reception data of the identified application and evaluates a change in the communication environment for each application.

[0059] Moreover, according to the first embodiment, a communication environment evaluation method can also be provided. This communication environment evaluation method is executed by the communication environment evaluation device 10, and is characterized by including the steps of acquiring reception data of communication packets of a plurality of applications transmitted between an on-board wireless communication device 3 installed on a vehicle and a ground wireless communication device 8 installed on the ground, identifying the application of the communication packets, and analyzing the reception data of the identified application to evaluate the communication environment for each application. The communication environment evaluation method may also be executed by the communication environment evaluation system 1.

[0060] Embodiment 2 12 is a diagram showing a configuration example of a communication environment evaluation system 1A according to the second embodiment. The communication environment evaluation system 1A further includes a data aggregation device 9 in addition to the components of the communication environment evaluation system 1. Furthermore, while the communication environment evaluation system 1 includes a communication environment evaluation device 10 connected to a ground wireless communication device 8, the communication environment evaluation system 1A includes a communication environment evaluation device 10A connected to an on-board wireless communication device 3. The following mainly describes the differences from the communication environment evaluation system 1.

[0061] The communication environment evaluation system 1A analyzes communication packets received on the vehicle 2 side. Note that, although only one vehicle 2 is shown in Fig. 12, in reality, the communication environment evaluation system 1A has an on-board wireless communication device 3 and a communication environment evaluation device 10A installed in each of the multiple vehicles 2, and a data aggregation device 9 installed on the ground side aggregates the evaluation results and information on feature quantities from the communication environment evaluation devices 10A mounted on each of the multiple vehicles 2.

[0062] Fig. 13 is an explanatory diagram of the function of the data aggregating device 9 in Fig. 12. The data aggregating device 9 has an evaluation result aggregating DB 91 and a feature amount aggregating DB 92. The data aggregating device 9 aggregates the evaluation results of the communication environment evaluation device 10A and information on the feature amounts from each of the multiple vehicles 2-1 to 2-n. The data aggregating device 9 accumulates the aggregated evaluation results in the evaluation result aggregating DB 91, and accumulates the aggregated feature amounts and trained models in the feature amount aggregating DB 92.

[0063] The functional configuration of the communication environment assessment device 10A is similar to that of the communication environment assessment device 10 according to the first embodiment. However, since the data acquired by the information acquisition unit 11 is only data of communication packets received by the vehicle 2 in which the communication environment assessment device 10A is installed, the vehicle conditions and operating conditions are fixed.

[0064] Fig. 14 is a diagram showing an example of received data acquired by the communication environment evaluation device 10A shown in Fig. 12. The received data shown in Fig. 14 includes an application type, a time period indicating the time when a communication packet was received, a reception time and an acquisition date, a section and location information indicating the location of the vehicle 2, a vehicle condition, and an operating condition. Compared with the received data in the first embodiment shown in Fig. 3, it is different in that the vehicle condition and the operating condition are fixed.

[0065] The operation of the communication environment assessment device 10A is similar to that of the communication environment assessment device 10 according to the first embodiment, but a learning device may be provided in the feature aggregation DB 92 to generate a trained model based on data aggregated for each vehicle condition and operating condition.

[0066] Fig. 15 is a flowchart for explaining the learning process in the second embodiment. The process from step S101 to step S104 is the same as that in the first embodiment shown in Fig. 7. However, the "received communication packet" is the "communication packet received by the on-board wireless communication device 3". Furthermore, the process from step S101 to step S104 is executed in each of the multiple vehicles 2.

[0067] After the features are calculated for each vehicle 2, the data of each vehicle 2 is aggregated and stored in the feature aggregation DB 92 of the data aggregating device 9 (step S107). The data accumulated in the feature aggregation DB 92 is used as learning data and a learner is trained to generate a trained model (step S108). The data aggregating device 9 also stores the generated trained model in each vehicle 2 (step S109).

[0068] In addition, the information on the features stored in the feature DB 14 of each vehicle 2 and the trained model may be stored in a database in advance.

[0069] As described above, the communication environment evaluation device 10A according to the second embodiment is installed in a vehicle 2, whereas the communication environment evaluation device 10 according to the first embodiment is installed on the ground. In this case, the information acquisition unit 11 acquires reception data of a communication packet transmitted by the ground wireless communication device 8 and received by the on-board wireless communication device 3. The communication environment evaluation device 10 installed on the ground as in the first embodiment acquires reception data of communication packets from a plurality of vehicles 2, but as described above, the communication environment evaluation device 10A installed in a vehicle 2 acquires reception data of a communication packet received by one vehicle 2. Therefore, the communication environment evaluation system 1A according to the second embodiment further includes a data aggregation device 9 that is installed on the ground and aggregates evaluation results transmitted from the plurality of communication environment evaluation devices 10A. This makes it possible to check the communication environment of each vehicle 2 operating along the line to be managed. In addition, by aggregating information on the feature amount of each vehicle 2, it becomes possible to share data having the same vehicle conditions and operating conditions with other vehicles 2.

[0070] Embodiment 3 A communication environment evaluation system 1B (not shown) according to the third embodiment has a communication environment evaluation device 10B instead of the communication environment evaluation device 10 of the communication environment evaluation system 1 according to the first embodiment. Other configurations of the communication environment evaluation system 1B are similar to those of the first embodiment.

[0071] The communication environment evaluation device 10B has the same functional configuration as the communication environment evaluation device 10. However, since some operations are different from those of the communication environment evaluation device 10, only the different parts will be described below using the symbols of the communication environment evaluation device 10. The communication environment evaluation device 10B performs learning data labeling in advance for data acquired for each application type, time period, section, vehicle condition, and operating condition, and analyzes the data. The difference from the first embodiment is the processing in the feature calculation unit 13 and the operation related to the generation of a trained model in the feature DB 14. In the third embodiment, the parts different from the first embodiment will be mainly described, and the description of the parts similar to the first embodiment will be omitted.

[0072] Fig. 16 is an explanatory diagram of a calculation process of a reception interval of communication packets in the third embodiment. After the application identification unit 12 classifies the reception data for each application type, time period, section, vehicle condition, and operating condition, the feature calculation unit 13 calculates the reception interval of the communication packets. In the first embodiment, the calculation of the reception interval was performed for each data classified for each time period, section, vehicle condition, and operating condition in each application, and divided for each PDF calculation section, but in the third embodiment, the reception interval is calculated collectively without providing a PDF calculation section. In addition, the feature calculation unit 13 calculates a probability density function from the reception interval.

[0073] FIG. 17 is a flowchart for explaining the learning process in the third embodiment. The processes in steps S101 to S105 are the same as those in the first embodiment. However, as described above, in the calculation of the feature amount in step S104, the reception interval and the PDF are calculated without providing a PDF calculation section. The feature amount DB14 divides the classified data into groups by clustering (step S110). In addition, the feature amount DB14 causes a learner to learn the accumulated data, and generates a learned model for each group (step S111).

[0074] FIG. 18 is an explanatory diagram of the learning process in the third embodiment. As shown in FIG. 16, the PDF of the reception interval is subdivided for each application based on the time period, section, vehicle condition, and operation condition. At this time, the number of labels of the learning data increases by the number of combinations of conditions to be classified. For this reason, the feature DB 14 groups the data subdivided based on the time period, section, vehicle condition, and operation condition into data with high similarity by clustering. The clustering method is not particularly limited. For example, the feature DB 14 may use a hierarchical clustering method such as the group average method, Ward's method, or the shortest distance method, or may use a non-hierarchical clustering method such as the k-means method. This has the effect of reducing the number of labels of the learning data and further reducing the number of learning data. It is assumed that the number of groups classified by clustering can be set arbitrarily. The feature DB 14 generates a learned model from a learning device for each group obtained by clustering.

[0075] As described above, in the communication environment evaluation device 10B according to the third embodiment, the feature DB 14 can group the feature calculated by the feature calculation unit 13 for each of the above classifications based on the values ​​of the received data by clustering, into groups of data with high similarity, and store trained models for outputting evaluation results of the communication environment from the feature generated for each of the classified groups in association with the groups. This provides the effect of reducing the number of labels of the training data, in addition to the effect of the first embodiment, since the training data is grouped by clustering before the generation of the trained model. Therefore, the training data can be collected efficiently.

[0076] Embodiment 4 19 is a diagram showing a configuration example of a communication environment evaluation system 1C according to the fourth embodiment. The communication environment evaluation system 1C includes a communication environment evaluation device 10C that evaluates a communication environment for each application group, which is a group of a plurality of applications, instead of the communication environment evaluation device 10 of the communication environment evaluation system 1.

[0077] The functional configuration of the communication environment evaluation device 10C is the same as that of the communication environment evaluation device 10. However, the communication environment evaluation device 10C evaluates only one representative application among the application group, and sets it as the evaluation result of the applications included in the same application group. Alternatively, the communication environment evaluation device 10C may acquire and evaluate data on a plurality of applications included in the same application group, regarding them as the same type. As the other operations are the same as those of the first embodiment, detailed explanations will be omitted.

[0078] As described above, in the communication environment evaluation system 1C according to the fourth embodiment, a plurality of applications are classified into application groups each of which is a group of applications having similar communication conditions, and the evaluation unit 15 can evaluate the communication environment for each application group. For example, the evaluation unit 15 can evaluate only one representative application from the application group as an evaluation result for the application group, or can handle data by regarding a plurality of applications included in the same application group as being of the same type. In either case, it becomes unnecessary to analyze each application individually, and applications having high similarity can be evaluated as an application group. Therefore, in addition to the effect of the first embodiment, the effect of improving the processing efficiency in data acquisition and evaluation can be achieved.

[0079] FIG. 20 is a diagram showing a configuration example of a communication environment evaluation system 1D according to a modified example of the fourth embodiment. In the communication environment evaluation system 1C shown in FIG. 19, the communication environment evaluation device 10C is installed on the ground side, whereas in FIG. 20, the communication environment evaluation device 10D is installed on a vehicle 2, and a data aggregating device 9 is installed on the ground, which is different. The communication environment evaluation device 10D evaluates the communication environment for each application group that groups together a plurality of applications, similar to the communication environment evaluation device 10C. The communication environment evaluation device 10D is also installed on a vehicle 2, similar to the communication environment evaluation device 10A of the second embodiment, and analyzes communication packets received by the on-board wireless communication device 3.

[0080] Embodiment 5. 21 is a diagram showing a configuration example of a communication environment evaluation system 1E according to the embodiment 5. In the communication environment evaluation system 1 according to the embodiment 1, the on-board wireless communication device 3 and the ground wireless communication device 8 are connected via one type of wireless communication network, whereas in the communication environment evaluation system 1E, the on-board wireless communication device 3 and the ground wireless communication device 8 are connected via multiple types of wireless communication networks.

[0081] The communication environment evaluation system 1E includes an on-board wireless communication device 3 mounted on a vehicle 2, on-board terminals 4-1, 4-2 corresponding to each of the multiple wireless communication networks, base stations 5-1, 5-2 corresponding to each of the multiple wireless communication networks, core network devices 6-1, 6-2 corresponding to each of the multiple wireless communication networks, a connection router 7, a ground wireless communication device 8, and a communication environment evaluation device 10.

[0082] In the example shown in Fig. 21, the on-board wireless communication device 3 and the ground wireless communication device 8 are connected by a route via a 5G network and a route via an LTE (Long Term Evolution) network. The 5G network and the LTE network may be public networks or private networks. In other words, examples of the wireless communication network to be used include a public network 5G, a public network LTE, a private network local 5G, a private network private LTE, a private network designed and managed by the railway operator itself, and the like.

[0083] In the communication environment evaluation system 1E, each of a plurality of applications uses a different wireless communication network according to the requirements of the application. The distribution of the reception intervals of the communication packets for each application acquired by the communication environment evaluation device 10 tends to change according to the transmission cycle of the application and the scheduling of the wireless communication network used.

[0084] The communication environment evaluation device 10 collects learning data for each application in advance, so it is possible to perform evaluation according to the requirements of the application and the characteristics of the wireless communication network. However, it is not assumed that the wireless communication network to be used will be switched midway depending on the communication environment, priority, etc.

[0085] As described above, in the communication environment evaluation system 1E according to the fifth embodiment, the on-board wireless communication device 3 and the ground wireless communication device 8 are connected via a plurality of types of wireless communication networks. Each application uses a wireless communication network having suitable characteristics according to the requirements of the application. In this way, in addition to the effect of the first embodiment, the communication environment evaluation system 1E according to the fifth embodiment can achieve the effect of being able to evaluate the communication environment for each application even when each application is connected via a different wireless communication network.

[0086] FIG. 22 is a diagram showing a configuration example of a communication environment evaluation system 1F according to a modified example of the fifth embodiment. In the communication environment evaluation system 1E shown in FIG. 21, the communication environment evaluation device 10 is installed on the ground side, whereas in FIG. 22, the communication environment evaluation device 10 is installed on the vehicle 2, and the data aggregation device 9 is installed on the ground. In the communication environment evaluation system 1F, the on-board wireless communication device 3 and the ground wireless communication device 8 are also connected by multiple types of wireless communication networks. Each application uses a wireless communication network having suitable characteristics according to the requirements of the application. In the communication environment evaluation system 1F, the communication environment evaluation device 10 is also installed on the vehicle 2, similar to the communication environment evaluation device 10A of the second embodiment, and analyzes a communication packet received by the on-board wireless communication device 3.

[0087] Here, the hardware configuration will be described. Fig. 23 is a diagram showing an example of the hardware configuration of the communication environment evaluation devices 10, 10A, 10B, 10C, and 10D according to the first to fifth embodiments and the data aggregating device 9 according to the second embodiment.

[0088] 23 includes a memory 101, a processor 102, a storage 103, a communication I / F (Interface) 104, and an input / output I / F 105. The memory 101, the processor 102, the storage 103, the communication I / F 104, and the input / output I / F 105 are connected by a data transmission path for transmitting and receiving data to and from each other.

[0089] The memory 101 is, for example, a memory such as a random access memory (RAM) or a read only memory (ROM). The processor 102 is, for example, a processing device such as a central processing unit (CPU) or a graphics processing unit (GPU). The storage 103 is, for example, a storage device such as a hard disk drive (HDD), a solid state drive (SSD), or a memory card. The storage 103 may also be a memory such as a RAM or a ROM.

[0090] Storage 103 stores programs for realizing the functions of the components included in communication environment assessment devices 10, 10A, 10B, 10C, and 10D or data aggregating device 9. Processor 102 executes each of these programs to realize each function of the components included in communication environment assessment devices 10, 10A, 10B, and 10C or data aggregating device 9.

[0091] The communication I / F 104 transmits and receives data to and from an external device. For example, the communication I / F 104 communicates with the external device via a wired communication path.

[0092] The input / output I / F 105 is connected to an input device 106 and a display device 107. The input device 106 is a device that accepts operational input from an operator, and is, for example, a keyboard, a mouse, a touch sensor, etc. The display device 107 is a device that displays the drawing data processed by the processor 102 on a monitor.

[0093] The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies, or some or all of the embodiments may be combined with each other. Also, parts of the configurations may be omitted or modified without departing from the spirit of the invention. [Explanation of symbols]

[0094] 1, 1A, 1B, 1C, 1D, 1E, 1F communication environment evaluation system, 2, 2-1 to 2-n vehicles, 3 on-board wireless communication device, 4 on-board terminal, 5 base station, 6 core network device, 7 connection router, 8 ground wireless communication device, 9 data aggregation device, 10, 10A, 10B, 10C, 10D communication environment evaluation device, 11 information acquisition unit, 12 application identification unit, 13 feature calculation unit, 14 feature DB, 15 evaluation unit, 16 memory unit, 17 display unit, 101 memory, 102 processor, 103 storage, 104 communication I / F, 105 input / output I / F, 106 input device, 107 display device.

Claims

1. an information acquisition unit that acquires reception data of communication packets of a plurality of applications transmitted between an on-board wireless communication device installed in the vehicle and a ground wireless communication device installed on the ground; an application identification unit that identifies an application of the communication packet based on the received data; a feature calculation unit that calculates a reception interval of the communication packet and calculates a distribution of the reception interval; an evaluation unit that analyzes a distribution of the reception intervals of the communication packets of the identified application and evaluates a change in the communication environment for each application; A storage unit that accumulates the evaluation results of the evaluation unit; a display unit that displays, for each time period and for each section in which the vehicle is located, an application for which the evaluation results stored in the storage unit are to be displayed, vehicle conditions of a vehicle in which the on-board wireless communication device that transmits the communication packets is installed, and operating conditions of the vehicle; A communication environment evaluation device comprising:

2. An information acquisition unit that acquires reception data of communication packets of a plurality of applications transmitted between an on-board wireless communication device installed in a vehicle and a ground wireless communication device installed on the ground; an application identification unit that identifies an application of the communication packet based on the received data and classifies the communication packet for each application according to a time zone and a section in which the vehicle is located; a feature amount calculation unit that calculates a reception interval of the communication packets for each classification by the application identification unit and calculates a distribution of the reception intervals; an evaluation unit that analyzes a distribution of the reception intervals of the communication packets of the identified application and evaluates a change in the communication environment for each application for each classification; A communication environment evaluation device comprising:

3. The application identification unit classifies the communication packets according to vehicle conditions of a vehicle in which the on-board wireless communication device that transmits the communication packets is installed and operating conditions of the vehicle.

3. The communication environment evaluation device according to claim 2.

4. a feature amount database that accumulates the distribution of the reception intervals calculated by the feature amount calculation unit for each classification based on the reception data; 3. The communication environment evaluation device according to claim 1, further comprising:

5. The feature database stores, for each classification, a trained model for outputting an evaluation result of the communication environment that is generated based on the distribution of the reception intervals calculated by the feature calculation unit.

5. The communication environment evaluation device according to claim 4.

6. The evaluation unit acquires the trained model corresponding to the classification of the received data of the communication packets from the feature database, and evaluates the communication environment using the distribution of the reception intervals of the communication packets and the acquired trained model.

6. The communication environment evaluation device according to claim 5,

7. The communication environment evaluation device is installed on the ground, The information acquisition unit acquires the received data of the communication packet transmitted by the on-board wireless communication device and received by the ground wireless communication device.

3. The communication environment evaluation device according to claim 1, wherein the communication environment evaluation device is a communication environment evaluation device.

8. The communication environment evaluation device installed in the vehicle, The information acquisition unit acquires the received data of the communication packet transmitted by the ground wireless communication device and received by the on-board wireless communication device.

3. The communication environment evaluation device according to claim 1, wherein the communication environment evaluation device is a communication environment evaluation device.

9. The information acquisition unit acquires the reception data including at least one of information indicating a type of application, information indicating a reception time of the communication packet, and vehicle information indicating a feature of a vehicle in which the on-board wireless communication device that transmits the communication packet is installed.

2. The communication environment evaluation device according to claim 1,

10. The vehicle information includes at least one of location information of the vehicle, vehicle conditions of the vehicle, and operating conditions of the vehicle.

10. The communication environment evaluation device according to claim 9,

11. a feature database that groups the distribution of the reception intervals calculated by the feature calculation unit for each classification based on the value of the reception data by clustering, and accumulates a trained model for outputting an evaluation result of the communication environment from the distribution of the reception intervals generated for each classified group, in association with the group; 3. The communication environment evaluation device according to claim 1, further comprising:

12. The plurality of applications are classified into application groups each including a plurality of applications having similar communication conditions; The evaluation unit evaluates the communication environment for each of the application groups or for one application among the application groups as an evaluation of the application groups.

3. The communication environment evaluation device according to claim 1, wherein the communication environment evaluation device is a communication environment evaluation device.

13. A communication environment evaluation system for evaluating a communication environment of communication packets of a plurality of applications transmitted between an on-board wireless communication device installed in a vehicle and a ground wireless communication device installed on the ground, comprising: an information acquisition unit that acquires reception data of communication packets of the applications transmitted between the on-board wireless communication device and the ground wireless communication device; an application identification unit that identifies an application of the communication packet based on the received data; an evaluation unit that analyzes a distribution of reception intervals of the communication packets of the identified application and evaluates a change in the communication environment for each application; A storage unit that accumulates the evaluation results of the evaluation unit; a display unit that displays, for each time period and for each section in which the vehicle is located, an application for which the evaluation results stored in the storage unit are to be displayed, vehicle conditions of a vehicle in which the on-board wireless communication device that transmits the communication packets is installed, and operating conditions of the vehicle; A communication environment evaluation device having A communication environment evaluation system comprising:

14. A communication environment evaluation system for evaluating a communication environment of communication packets of a plurality of applications transmitted between an on-board wireless communication device installed in a vehicle and a ground wireless communication device installed on the ground, comprising: an information acquisition unit that acquires reception data of communication packets of the applications transmitted between the on-board wireless communication device and the ground wireless communication device; an application identification unit that identifies an application of the communication packet based on the received data and classifies the communication packet for each application according to a time zone and a section in which the vehicle is located; an evaluation unit that analyzes a distribution of reception intervals of the communication packets of the identified application for each classification by the application identification unit, and evaluates a change in the communication environment for each application for each classification; A communication environment evaluation device having A communication environment evaluation system comprising:

15. the communication environment assessment device is mounted in each of the plurality of vehicles, a data aggregating device that is installed on the ground and aggregates evaluation results transmitted from the plurality of communication environment assessment devices; 15. The communication environment evaluation system according to claim 13, further comprising:

16. The on-board wireless communication device and the ground wireless communication device are connected to each other via a plurality of types of wireless communication networks.

15. The communication environment evaluation system according to claim 13 or 14.

17. acquiring reception data of communication packets of a plurality of applications transmitted between an on-board wireless communication device installed in a vehicle and a ground wireless communication device installed on the ground; identifying an application of the communication packet based on the received data; calculating a reception interval of the communication packet and calculating a distribution of the reception intervals; analyzing a distribution of the reception intervals of the communication packets of the identified applications and evaluating a communication environment for each application; accumulating the evaluation results of the communication environment; displaying, for each time period and for each section in which the vehicle is located, an application for which the accumulated evaluation results are to be displayed, vehicle conditions of a vehicle in which the on-board wireless communication device that transmits the communication packets is installed, and operating conditions of the vehicle; A communication environment evaluation method comprising:

18. A step of acquiring received data of communication packets of a plurality of applications transmitted between an on-board wireless communication device installed in a vehicle and a ground wireless communication device installed on the ground; identifying an application of the communication packet based on the received data, and classifying the communication packet for each application according to a time period and a section in which the vehicle is located; calculating a reception interval of the communication packets for each classification by the classifying step, and calculating a distribution of the reception intervals; analyzing a distribution of the reception intervals of the communication packets of the identified application and evaluating the communication environment of each application for each classification; A communication environment evaluation method comprising:

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