JP7084890B2 - Evaluation system and evaluation method - Google Patents

Description

The present invention relates to an evaluation system and method for a system using wireless communication.

In a multi-hop wireless communication network system, there is a technique described in Japanese Patent Application Laid-Open No. 2015-12427 (Patent Document 1) for evaluating the reliability of communication between transmission / reception devices. In this publication, "a receiving unit that receives radio waves from a target wireless device, an electric field strength determining unit that determines whether or not the electric field strength of the radio wave from the wireless device is stronger than a predetermined electric field strength, and a wireless device. When the electric field strength from is stronger than the predetermined electric field strength, the target wireless device to the receiver are independent based on the position information and environmental information of multiple wireless devices installed in the communication section to the receiver. A communication reliability evaluation device including a redundant route number calculation unit for calculating the number of redundant routes and a reliability evaluation unit for evaluating communication reliability based on the number of independent redundant routes is described. Further, in the evaluation method described in this publication, the density of buildings existing in one grid when the area where communication is performed is divided into a grid is used as environmental information.

Japanese Unexamined Patent Publication No. 2015-12427

In Patent Document 1, in the area where wireless communication is performed, the quality of wireless communication due to a shield such as a vehicle that dynamically appears and disappears with the passage of time, or an interference wave source such as a smartphone held by a moving person. And the evaluation considering the influence on the wireless communication reliability has not been made. Therefore, it is difficult to accurately evaluate the wireless communication quality and wireless communication reliability because the evaluation is limited to considering only the static factors that affect the wireless communication quality such as the density of buildings and the wireless communication reliability. ..

Therefore, an object of the present invention is to evaluate in consideration of static environmental factors and dynamic environmental factors that affect wireless communication quality and wireless communication reliability.

A typical example of the invention disclosed in the present application is as follows. That is, it is an evaluation system that evaluates a wireless system that performs wireless communication, and information on the wireless system to be evaluated and environmental information on the wireless communication environment in which wireless communication is performed in the wireless system are input to evaluate the wireless communication quality. An input / output unit that outputs the result and the evaluation result of the reliability of the wireless system, a static environment evaluation model for static environment information including the shape of the space where wireless communication is performed, and an evaluation in the static environment evaluation model. The parameters, the dynamic environment evaluation model for the time-varying dynamic environmental information including the information of the moving obstacle and the moving interference wave source, and the evaluation parameters in the dynamic environment evaluation model are set for each wireless communication environment. The wireless communication quality evaluation model database stored in the wireless communication quality evaluation model database, and the evaluation model and evaluation parameters required for the wireless communication quality evaluation according to the position of the wireless communication device are acquired from the wireless communication quality evaluation model database. It is characterized by including a wireless communication quality evaluation unit that evaluates the wireless communication quality of the wireless system and a system reliability evaluation unit that evaluates the reliability of the wireless system based on the evaluation result by the wireless communication quality evaluation unit. And.

According to one aspect of the present invention, the wireless communication quality and the reliability of the wireless communication system can be evaluated in consideration of dynamic environmental information. Issues, configurations and effects other than those mentioned above will be clarified by the description of the following examples.

It is a figure which shows the input / output relationship of the simulator for reliability evaluation of the wireless train control system of this Example. It is a block diagram which shows the structure of the simulator for reliability evaluation of the wireless train control system of this Example. It is a flowchart which shows the example of the processing procedure by the wireless train control system simulator of this Example. It is a figure which shows the example of the screen which displays the wireless communication quality evaluation result and the reliability evaluation result by the wireless train control system simulator of this Example. It is a figure which shows the example of the wireless communication quality evaluation event list in the wireless train control system simulator of this Example. It is a flowchart which shows the example of the procedure of the wireless communication quality evaluation event processing in the event-driven simulator of this embodiment. It is a figure which shows the configuration example of the route composition information list used by the wireless train control system simulator of this Example. It is a figure which shows the structural example of the wireless communication quality evaluation parameter list included in the wireless communication quality evaluation model database of the wireless train control system simulator of this Example. It is a flowchart which shows the procedure of the shield information setting event processing in the wireless train control system simulator of this embodiment. It is a figure which shows the configuration example of the shielding event list by another train in the wireless train control system simulator of this Example. It is a figure which shows the concept of shielding by the preceding train, the following train and the oncoming train in the wireless train control system simulator of this embodiment. It is a flowchart which shows the procedure of the influence evaluation process on the wireless communication quality by the existence of a shield in the wireless train control system simulator of this Example. It is a figure which shows the model of the shielding attenuation characteristic by the existence of each of the preceding train, the following train, and the oncoming train for each track environment in the wireless train control system simulator of this embodiment. It is a flowchart which shows the procedure of the communication error occurrence rate calculation processing in the wireless train control system simulator of this Example. The relationship between the desired wave power-to-interference wave power ratio (SIR) and the frame error rate (FER) of the on-board and terrestrial radios used in the wireless train control system in the wireless train control system simulator of this embodiment. It is a figure which shows. It is a flowchart which shows the procedure of the system reliability evaluation processing in the wireless train control system simulator of this Example. It is a block diagram which shows the physical structure of the wireless train control system simulator of this Example.

Hereinafter, examples will be described with reference to the drawings.

[Example 1]
FIG. 1 is a diagram showing an input / output relationship of a simulator for reliability evaluation of the wireless train control system of this embodiment.

The wireless train control system simulator 104 determines the wireless communication quality and wireless communication reliability between the on-board radio station mounted on the train and the terrestrial radio station installed along the railroad track in the wireless train control system. evaluate. A simulation evaluation scenario 107 is input to the wireless train control system simulator 104. The simulation evaluation scenario 107 describes the wireless train control system specification information 101, train operation information 102 which is information for simulating the running of the train to be evaluated (for example, a train diagram), and the environment of the railway line to be evaluated. Includes the indicated railroad route information 103. Further, the simulation evaluation result 108, which is the output of the wireless train control system simulator 104, includes the wireless communication quality evaluation result 105 and the system reliability evaluation result 106.

FIG. 2 is a block diagram showing a configuration of a simulator for reliability evaluation of the wireless train control system of this embodiment.

First, the input configuration of the wireless train control system simulator 104 will be described. The wireless train control system specification information 101 in FIG. 1 includes terrestrial radio station location information 201 indicating the position where the terrestrial radio station is installed on the route, and radio station specifications of the on-board radio station and the terrestrial radio station (for example, for example. Control to switch between the frequency used to calculate radio wave propagation, output, antenna directionalness, gain, etc.) 202 and the terrestrial radio station to which the on-board radio station connects as the train progresses (called handover control). The handover control information (for example, the handover condition (RSSI threshold value), the position where the handover is executed) 203 that defines the specifications of the above is included. The train operation information 102 includes information on the relationship between time and train position as a train diagram. The railway line information 103 in FIG. 1 includes the shield information 204 indicating the dynamic appearance and disappearance of the shield in the environment where the wireless communication of the wireless train control system is performed, and the railway line to be evaluated. Includes track environment information 205 indicating the environment (track shape, underground or light, double track or single track, etc.).

Next, the internal configuration of the wireless train control system simulator 104 in units of functional blocks will be described. The operation of the wireless train control system itself is simulated by the system operation simulating unit 206 based on the information of the terrestrial radio station station position information 201, the radio equipment specification 202, and the handover control information 203. Similarly, the train running on the line in which the wireless train control system to be evaluated is installed is simulated by the train operation simulating unit 207 based on the train operation information 102. The train operation simulation unit 207 changes the position of the train, that is, the position of the on-board radio station, and the terrestrial radio station to which the on-board radio station is connected with time as the simulation progresses.

The wireless communication environment between the on-board radio station and the terrestrial radio station in the wireless train control system, and between the radio station in those systems and the radio station that is the source of interference outside the wireless train control system is a vehicle. Route environment information 205 that specifies the track environment at a position determined by the distance from the starting point of the evaluation target route of the upper radio station and terrestrial radio station, and information of other trains that appear and disappear at the specified time are specified. It is simulated by the route environment simulation unit 208 based on the shield information 204.

In the wireless communication quality evaluation unit 210, the quality of wireless communication for controlling the wireless train at each train position when the train travels on the railway line to be evaluated is the system operation simulation unit 206, the train operation simulation unit 207, and the train operation simulation unit 207. Based on the information of the communication environment simulated by the route environment simulation unit 208 and the information of the wireless communication quality evaluation model database 209 that stores the evaluation model necessary for the wireless communication quality evaluation at the existing positions of the on-board radio station and the terrestrial radio station. Will be evaluated. The system reliability evaluation unit 211 evaluates the reliability of the wireless communication system unit in the wireless train control system based on the evaluation result of the wireless communication quality.

Finally, the output configuration of the wireless train control system simulator 104 will be described. As the output of the wireless train control system simulator 104, the wireless communication quality evaluation result 105 regarding the wireless train control system at each position of the train traveling on the railway line to be evaluated, and the wireless communication system in the wireless train control system. The system reliability evaluation result 106 of the unit is obtained.

FIG. 17 is a block diagram showing a physical configuration of the wireless train control system simulator 104 of this embodiment.

The wireless train control system simulator 104 of this embodiment is composed of a computer having a processor (CPU) 11, a memory 12, an auxiliary storage device 13, and a communication interface 14. The wireless train control system simulator 104 may have an input interface 15 and an output interface 18.

The processor 11 is an arithmetic unit that executes a program stored in the memory 12. By executing various programs, the processor 11 executes each part of the wireless train control system simulator 104 (for example, system operation simulation unit 206, train operation simulation unit 207, route environment simulation unit 208, wireless communication quality evaluation unit 210, system. The function by the reliability evaluation unit 211 etc.) is realized. A part of the processing performed by the processor 11 by executing the program may be executed by another arithmetic unit (for example, hardware such as ASIC or FPGA).

The memory 12 includes a ROM which is a non-volatile storage element and a RAM which is a volatile storage element. The ROM stores an invariant program (for example, BIOS) and the like. The RAM is a high-speed and volatile storage element such as a DRAM (Dynamic Random Access Memory), and temporarily stores a program executed by the processor 11 and data used when the program is executed.

The auxiliary storage device 13 is a large-capacity, non-volatile storage device such as a magnetic storage device (HDD) or a flash memory (SSD). Further, the auxiliary storage device 13 stores data used by the processor 11 when executing the program (for example, wireless communication quality evaluation model database 209) and a program executed by the processor 11. That is, the program is read from the auxiliary storage device 13, loaded into the memory 12, and executed by the processor 11 to realize each function of the wireless train control system simulator 104.

The communication interface 14 is a network interface device that controls communication with other devices according to a predetermined protocol.

The input interface 15 is an interface to which an input device such as a keyboard 16 or a mouse 17 is connected and receives input from an operator. The output interface 18 is an interface to which an output device such as a display device 19 or a printer (not shown) is connected and outputs a program execution result in a format that can be visually recognized by an operator. A user terminal connected to the wireless train control system simulator 104 via a network may provide an input device and an output device. In this case, the wireless train control system simulator 104 may have the function of a web server, and the user terminal may access the wireless train control system simulator 104 by a predetermined protocol.

The program executed by the processor 11 is provided to the wireless train control system simulator 104 via a removable medium (CD-ROM, flash memory, etc.) or a network, and is provided in a non-volatile auxiliary storage device 13 which is a non-temporary storage medium. Stored. Therefore, the wireless train control system simulator 104 may have an interface for reading data from removable media.

The wireless train control system simulator 104 is a computer system composed of a plurality of computers physically configured, or logically or physically configured, on a plurality of physical computer resources. It may operate on the built virtual computer. For example, the system operation simulation unit 206, the train operation simulation unit 207, the route environment simulation unit 208, the wireless communication quality evaluation unit 210, and the system reliability evaluation unit 211 may operate on separate physical or logical computers. , A plurality of combinations may be used to operate on one physical or logical computer.

FIG. 3 is a flowchart showing an example of a processing procedure by the wireless train control system simulator 104 of this embodiment. The operation based on the flowchart shown in FIG. 3 is as follows.

Step 301: When the wireless train control system simulator 104 is started, the evaluation process by simulation is started.

Step 302: The train operation simulation unit 207 reads information necessary for evaluation by simulation from each file of the simulation evaluation scenario 107. Specifically, the wireless train control system simulator 104 reads the wireless train control system specification information 101, the train operation information 102, and the railway line information 103.

Step 303: The train operation simulation unit 207 calculates the relationship (referred to as a train operation curve) between the time and the train position in the railway line to be evaluated based on the input train operation information 102. The train operation curve prepared in advance for each line and train type may be used.

Step 304: In the wireless train control system simulator 104, the train operation simulation unit 207 changes the state of the wireless train control system to be evaluated, changes in the wireless communication environment, the appearance or disappearance of other trains as a shield, and the system. The management of the failure and recovery of the wireless communication equipment in the system, the wireless communication quality evaluation request for each train position, etc. are treated as events in the event-driven simulation, and the queue for managing these events is set before the simulation starts. initialize.

Step 305: The train operation simulation unit 207 adds a wireless communication quality evaluation event for evaluating the wireless communication quality related to the wireless train control to the event queue at predetermined time intervals. The wireless communication quality evaluation event added to the event queue may be managed by the table shown in FIG. Based on the information of the train operation curve obtained in step 303, the position of the train (on-board radio station) at the time of occurrence of each radio quality evaluation event is obtained.

Step 306: Based on the obstruction information 204 in FIG. 2, the route environment simulation unit 208 sets an event queue for a obstruction event that causes other trains as obstructions to appear or disappear around the own train at a time specified by the simulator user. Add to. The shield information specified by the shield information 204 may be managed by the table shown in FIG. The shielding event is enqueued at two times, the occurrence timing and the end timing of the shielding.

Step 307: The route environment simulation unit 208 holds a failure / failure recovery event that simulates a failure of the wireless device and a state change of the failure recovery at a specified time with respect to the wireless devices constituting the wireless train control system. Add to. For example, it evaluates a case where a redundant wireless device fails in a place where the radio wave environment is bad.

Step 308: The wireless communication quality evaluation unit 210 determines whether or not the event queue is empty. If the event queue is empty, the process proceeds to step 316. If the event queue is not empty, the entries in the event queue are sorted by time in ascending order, i.e., in ascending order of time, and the process proceeds to step 309.

Step 309: The wireless communication quality evaluation unit 210 retrieves (dequeues) the event at the head of the event queue, that is, the event with the youngest time from the event queue. The time for simulation management of the wireless train control system simulator 104 is advanced to the time of the extracted event.

Step 310: If the event extracted in step 309 is a wireless communication quality evaluation event, the process proceeds to step 313. If not, the process proceeds to step 311.

Step 311: If the event fetched in step 309 is a shielding event, the process proceeds to step 314. If not, the process proceeds to step 312.

Step 312: If the event taken out in step 309 is a failure / failure recovery event, the process proceeds to step 315. If not, the process proceeds to step 308.

Step 313: The wireless communication quality evaluation unit 210 evaluates the quality of wireless communication related to wireless train control based on the information of the train (on-board radio station) position specified as the attribute of the event extracted in step 309. .. The processing procedure for wireless communication quality evaluation will be described later with reference to FIG. After the wireless communication quality evaluation is completed, the process proceeds to step 308 to process the next event in the event queue.

Step 314: The wireless communication quality evaluation unit 210 evaluates the type of other train (either the preceding train, the following train, or the oncoming train) as a shield specified as the attribute of the event taken out in step 309. Based on the distance from the train, the existence / disappearance state of the shield around the train to be evaluated is set. The processing procedure for setting the shielding information will be described later with reference to FIG. After the setting of the obstruction information is completed, the process proceeds to step 308 to process the next event in the event queue.

Step 315: The wireless communication quality evaluation unit 210 sets the device status (whether or not it is out of order) of the wireless devices constituting the wireless train control system. After setting, the process proceeds to step 308 to process the next event in the event queue.

Step 316: The system reliability evaluation unit 211 is a wireless train under the wireless communication conditions assumed by the simulation evaluation scenario 107 based on the wireless communication quality evaluation result 105 corresponding to the position of each train (on-board radio station). The reliability of the wireless communication system unit in the control system is evaluated, and the wireless communication quality evaluation result 105 and the system reliability evaluation result 106 are output to the screen.

Step 317: The process of simulation evaluation in the wireless train control system simulator 104 is terminated.

FIG. 4 is a diagram showing an example of a screen displaying the wireless communication quality evaluation result 105 and the system reliability evaluation result 106 by the wireless train control system simulator 104 of this embodiment.

The wireless communication quality evaluation result 105 and the system reliability evaluation result 106 are displayed on the graphical interface 401. The wireless communication quality evaluation result 105 shows a graph 402 showing the relationship between the train (on-board radio station) position and the frame error rate (FER) in the kilometer direction (the direction in which the train travels), and the train (on-board radio station) position. Graph 403 showing the relationship between the desired wave power and the interference wave power ratio (SIR), graph 404 showing the relationship between the train (on-board radio station) position and the received signal strength (RSSI) of the desired wave and the interference wave, and It is displayed as a graph 405 showing the relationship between the train (on-board radio station) position and the train running speed. The evaluation results required for displaying these graphs can also be output as a text file such as a CSV file as the output of the simulator. The evaluation results of wireless system reliability are displayed in Table 406, which has columns for each item of evaluation index name, value, evaluation interval, and evaluation period. As for the probability of occurrence of the emergency brake displayed in Table 406, the probability of all trains in the evaluation period, the probability of each section of one train, and the like are displayed according to the purpose of evaluation. Further, as the probability value, the highest probability in the interval, the statistically processed overall probability, and the like may be displayed according to the purpose of the evaluation. Further, the data displayed in Table 406 can also be output as a text file such as a CSV file as the output of the simulator.

FIG. 5 is a diagram showing an example of a wireless communication quality evaluation event list in consideration of train movement with the passage of time in the wireless train control system simulator 104 of this embodiment. In the wireless communication quality evaluation event list, one line represents one wireless communication quality evaluation event, and information on the train position at the time of event occurrence is retained. In the wireless communication quality evaluation event list, all the events to be evaluated in the wireless train control system simulator 104 are recorded in chronological order. As the time of the wireless communication quality evaluation event list, it is preferable to use the elapsed time from a predetermined point (for example, the starting station) of the train.

In the illustrated wireless communication quality evaluation event list, events are created at predetermined time intervals, but events may be created each time the train travels a predetermined distance.

FIG. 6 is a flowchart showing an example of the procedure of wireless communication quality evaluation event processing (S313) in the event-driven simulator of this embodiment. The operation based on the flowchart shown in FIG. 6 is as follows.

Step 601: When the wireless communication quality evaluation event processing (step 313) in FIG. 3 starts, the wireless communication quality evaluation unit 210 uses information on the train position, which is one of the attributes of the wireless communication quality evaluation event, to display the on-board radio station. Get a position. The position information of the on-board radio station managed inside the wireless train control system simulator 104 is updated to the position obtained from the event attribute. Since the on-board radio station is usually located on the leading vehicle, the position of the on-board radio station is the antenna position of the leading vehicle. Two antennas (on-board radio station) When configuring diversity, two antenna positions are acquired.

Step 602: The radio communication quality evaluation unit 210 is a radio of another radio communication system that uses the same frequency band as the frequency used for communication by the radio train control system based on the positions of the on-board radio station and the terrestrial radio station. (Interference wave source) information is acquired from the route environment information 205. The interference wave source is, for example, a radio device such as a smartphone owned by a passenger on the platform, a WiFi access point installed along the railway line, or the like.

Step 603: The wireless communication quality evaluation unit 210 determines the terrestrial radio station to which the on-board radio station is connected. Since there is a limit to the distance that one fixed terrestrial radio station can communicate with, it is necessary to switch the terrestrial radio station to which the on-board radio station is connected according to the movement of the train (on-board radio station). This connection destination switching process is called handover. The handover method used in the wireless train control system simulator 104 is specified in the handover control information 203. For example, one of the handover methods defined in the wireless train control system simulator 104 is a position-based handover method. In the position-based handover method, a handover point is set around the terrestrial radio station, and the connection is transferred to the designated terrestrial radio station when the train (on-board radio station) passes the handover point. The information of the handover point is specified in the handover control information 203. Further, as another handover method, a method of selecting the terrestrial radio station having the highest received power strength at the position of the on-board radio station as the connection destination may be used.

Step 604: The wireless communication quality evaluation unit 210 acquires the track environment at the positions of the on-board radio station and the terrestrial radio station from the track environment information 205 including the track environment at each point in the line to be evaluated. The acquired track environment information will be described later with reference to FIG. 7.

Step 605: The wireless communication quality evaluation unit 210 uses the evaluation model and evaluation parameters obtained in step 604 for the wireless communication quality evaluation in the line environment at the positions of the on-board radio station and the terrestrial radio station as the wireless communication quality evaluation model. Obtained from database 209. The evaluation model and evaluation parameters used for the wireless communication quality evaluation will be described later with reference to FIG.

Step 606: The wireless communication quality evaluation unit 210 refers to information on the on-board radio station managed inside the wireless train control system simulator 104, and other trains (preceding train, following train, oncoming) that serve as a shield in the surroundings. Determine if a train) exists. If another train that serves as a shield exists around the own train, the process proceeds to step 607. If there is no other train that serves as a shield around the own train, the process proceeds to step 608.

Step 607: When the wireless communication quality evaluation unit 210 has another train around the own train to be evaluated, the presence of the other train as a shield is present between the on-board radio station and the ground radio station to which it is connected. Evaluate the impact on wireless communication quality between. An example of the procedure for evaluating the influence of the presence of the shield on the communication quality will be described later with reference to FIG. After the evaluation of the influence of the presence of the shield on the communication quality is completed, the process proceeds to step 608.

Step 608: The wireless communication quality evaluation unit 210 determines the evaluation model and evaluation parameters used for the wireless communication quality evaluation obtained in step 605 when there is no other train around the own train to be evaluated, and the evaluation target train. The evaluation result of the influence on the radio communication quality due to the presence of the shield obtained in step 606 when another train is present around the radio, and the radio train control such as the antenna power and the antenna gain given by the radio specification 202. Evaluate the quality of radio communication between the on-board radio station and its connected terrestrial radio station based on information about the specifications of the radio used in the system. For example, as the wireless communication quality evaluation index, the received signal strength (RSSI) of the desired wave and the interfering wave and the desired wave received power to the interfering wave power ratio (SIR) at the positions of the on-board radio station and the terrestrial radio station are used. The evaluation result of the wireless communication index is the processing of all the wireless communication quality evaluation events in the wireless train control system simulator 104 for the screen output in the graph format shown in FIG. 4 and the file output in the text format such as CSV. Is retained until the end.

Step 609: The wireless communication quality evaluation unit 210 calculates the communication error occurrence rate using the calculation result of the wireless communication quality index between the on-board radio station and the connected terrestrial radio station obtained in step 608. An example of the calculation process of the communication error occurrence rate will be described later with reference to FIG.

Step 610: The wireless communication quality evaluation event processing (step 313) is completed.

As described above, in the wireless communication quality evaluation event processing (step 313), in step 606, another train as a shield that may affect the wireless communication quality is generated around the evaluation target train (on-board radio station). If it is determined to exist, in step 607, the magnitude of the influence on the radio communication quality due to the presence of another train as a shield is evaluated. As a result, in addition to the wireless communication quality evaluation using static environmental information, which is also handled in publicly known examples, wireless communication takes into consideration the influence of a shield whose position changes, which is one of the dynamic environmental information. We are evaluating the quality. In the wireless train control system simulator 104, the magnitude of the influence of the presence of the shield on the wireless communication quality is quantitatively evaluated as the amount of shield loss.

FIG. 7 is a diagram showing a configuration example of the route configuration information list 701 used by the wireless train control system simulator 104 of this embodiment.

The line composition information list 701 shown in FIG. 7 constitutes at least a part of the line environment information 205, and is based on criteria such as a straight line, a curve, a line shape such as a station, whether it is an underground section, whether it is a double track or a single line, and the like. The railway line to be evaluated is divided according to the classified railway environment, and the railway environment of each section is expressed. In step 604 of the wireless communication quality evaluation event processing shown in FIG. 6, the line environment name at the position of the on-board radio station and the position of the connected terrestrial radio station at the time when the event occurred is the starting point of the table shown in FIG. , Can be obtained by referring to the item at the end point.

Further, the route environment information 205 may include information on a radio device failure and information on an interference wave source. Information about a radio failure includes, for example, the location of the failure and the mode of the failure or the degree of deterioration of the radio communication quality caused by the failure. In particular, it is advisable to evaluate the deterioration of wireless communication quality by causing a failure in a place where the wireless environment is bad. Further, as a mode of failure, one of the redundant wireless devices fails. The information on the interference wave source is, for example, information such as a radio device owned by a passenger waiting at the home and a nearby WiFi access point.

FIG. 8 is a diagram showing a configuration example of the wireless communication quality evaluation parameter list 801 included in the wireless communication quality evaluation model database 209 of the wireless train control system simulator 104 of this embodiment.

The wireless communication quality evaluation parameter list 801 is held in the wireless communication quality evaluation model database 209 in FIG. In step 604 of the processing of the wireless communication quality evaluation event shown in FIG. 6, after acquiring the line environment name at the position of the on-board radio station at the time when the event occurred and the position of the terrestrial radio station to be connected, in step 605. , Refer to the wireless communication quality evaluation parameter list 801 and use the line environment name in the leftmost column to evaluate the evaluation model and evaluation required for wireless communication quality evaluation at the position of the on-board radio station and the position of the connected terrestrial radio station. You can get the parameters.

As described above, in step 604 of FIG. 6, the track environment name at the position of the on-board radio station of the train to be evaluated and the position of the ground radio station to be connected is created from the route environment information 205, and the route configuration information list 701 of FIG. 7 is created. In step 605 of FIG. 6, the track environment name obtained from the table of FIG. 8 is used to evaluate the radio communication quality at the position of the on-board radio station of the train to be evaluated and the position of the terrestrial radio station to be connected. By collectively acquiring the necessary evaluation models and evaluation parameters, the necessary evaluation models and parameters can be acquired at high speed. In particular, it is highly effective when the railway line to be evaluated is composed of a plurality of line environments and there are a plurality of evaluation parameters and evaluation models for wireless communication quality evaluation for one line environment.

FIG. 9 is a flowchart showing the procedure of the shielding information setting event processing (314) in the wireless train control system simulator 104 of this embodiment. The operation based on the flowchart shown in FIG. 9 is as follows.

Step 901: When the shielding information setting process (step 314) in FIG. 3 starts, it is determined whether or not the event handled by the shielding information setting process 314 is a shielding start event. If it is a shielding start event, the process proceeds to step 902, and if it is not a shielding start event, the process proceeds to step 904.

Step 902: If the event to be handled is a shield start event, another train that acts as a shield in the surroundings, which is one of the information of the train (on-board radio station) held inside the wireless train control system simulator 104. Set a flag to see if there is a train in the vicinity and set a situation where there is a train as a shield. It is preferable to have a flag indicating the existence of other trains around the own train for each type of other train (preceding train, following train, oncoming train).

Step 903: Similar to step 902, it is evaluated as another train that is a shield existing in the surroundings, which is one of the information of the train (on-board radio station) held inside the wireless train control system simulator 104. Set the distance to the target train.

Step 904: It is determined whether or not the event handled by the shielding information setting process 314 is a shielding end event. If it is a shielding start event, the process proceeds to step 905. If it is not a shielding start event, the process proceeds to step 907.

Step 905: A flag indicating whether or not there is another train that acts as a shield in the vicinity, which is one of the information of the train (on-board radio station) held inside the wireless train control system simulator 104. Take it down and set the situation where there is no train as a shield in the vicinity.

Step 906: Distance between another train that is a shield existing in the vicinity and the train to be evaluated, which is one of the information of the train (on-board radio station) held inside the wireless train control system simulator 104. Is initialized to 0.

Step 907: The shielding information setting process 314 is terminated.

FIG. 10 is a diagram showing a configuration example of a shielding event list by another train in the wireless train control system simulator 104 of this embodiment.

The shielding event list shown in FIG. 10 constitutes at least a part of the shielding information 204, and is given as the shielding information 204 which is one of the inputs of the wireless train control system simulator 104. The data recorded in one line of the list in FIG. 10 is a shielding event by another train. The shielding event includes the time when the shielding occurs, the time when the shielding ends, the type of shielding (preceding train, following train, oncoming train), the train number of the train to be evaluated equipped with the on-board radio station affected by the shielding, and the shielding. Includes data on the distance from the train to be evaluated to the obstruction when the type is the preceding train or the following train. The shielding event described in one line is processed by the shielding information setting event processing (314) twice, the occurrence time and the end time of the shielding.
But it may be.

The above-mentioned shield event list records the preceding train, the following train, and the oncoming train traveling on the same line as the type of shielding, but the trains traveling in the same direction on the tracks existing on the sides (parallel running). The train) may be recorded. In addition to trains, vehicles passing through railroad crossings provided on the line may be recorded. Since vehicles do not pass the railroad crossing at a set time, it is advisable to set a shielding event by the vehicle passing through the railroad crossing before and after the train to be evaluated travels around the railroad crossing.

FIG. 11 is a diagram showing the concept of shielding by a preceding train, a following train, and an oncoming train in the wireless train control system simulator 104 of this embodiment.

FIG. 11A shows the concept of shielding by a following train. A train that exists in front of the train on the same track as the own train, which is the train to be evaluated, is called a preceding train. There is a preceding train between the on-board radio station on the head side of the own train and the ground radio station to be connected, and the distance from the head position of the own train to the shield is d_0. When the distance d_BS to the terrestrial radio station is large, the preceding train becomes a shield existing on the propagation path of radio communication between the on-board radio station on the leading side of the own train and the terrestrial radio station to be connected.

FIG. 11B shows the concept of shielding by a following train. A train that exists behind the same track as the own train, which is the train to be evaluated, is called a succeeding train. Similar to the case of shielding by the preceding train shown in FIG. 11A, the following train exists between the on-board radio station on the rear side of the own train and the ground radio station to be connected, and the rear position of the own train. When the distance d_BS from the rear position of the own train to the ground radio station to which the on-board radio station is connected is larger than the distance d_0 from to the shield, the following train connects to the on-board radio station on the rear side of the own train. It is an obstacle existing on the propagation path of radio communication with the terrestrial radio station.

FIG. 11C shows the concept of shielding by an oncoming train. Obstruction by oncoming trains occurs only in sections of multiple tracks or more. A train that travels in the opposite direction on the track that exists on the side of the track on which the own train, which is the evaluation target train, is traveling is called an oncoming train. When an oncoming train exists and the ground radio station to which the on-board radio station of the own train is connected is on the opposite track side of the oncoming train, the oncoming train is connected to the on-board radio station of the own train. It is a shield that exists on the propagation path of radio communication between terrestrial radio stations.

FIG. 12 is a flowchart showing the procedure of the influence evaluation process (607) on the wireless communication quality due to the presence of the shield in the wireless train control system simulator 104 of this embodiment. The operation based on the flowchart of FIG. 12 is as follows.

Step 1201: When the evaluation process (step 607) of the influence of the presence of another train as a shield in FIG. 6 on the radio communication quality is started, the on-board radio station managed inside the wireless train control system simulator 104 is concerned. Refer to the information and obtain the distance between your own train and other trains in the case of shielding by the preceding train or the following train, and the distance between the on-board radio station of your own train and the connected ground radio station in the case of shielding by the oncoming train. do.

Step 1202: It is determined whether or not the terrestrial radio station to which the on-board radio station of the own train is connected exists at a position closer to that of the other train. If the terrestrial radio station to which the on-board radio station of the own train is connected is located closer to the other trains, it will be used as a shield between the on-board radio station of the own train and the terrestrial radio station to be connected. Since there are no other trains, it is judged that there is no influence due to the shielding, and the process proceeds to step 1205. On the other hand, if the ground radio station to which the on-board radio station of the own train is connected exists at a position farther than the other trains, it is determined that there is an influence due to the shielding, and the process proceeds to step 1203.

Step 1203: The track environment at the position of the on-board radio station is acquired from the track configuration information list 701 of FIG.

Step 1204: In the case of shielding by the preceding train or the following train, the track on which the own train exists is obtained from the wireless communication quality evaluation model database 209 of FIG. 2 based on the track environment at the position of the on-board radio station acquired in step 1203. An evaluation model of the influence of shielding by the preceding train and the following train in the environment is acquired, and the shielding attenuation amount is acquired as the magnitude of the influence of shielding according to the distance between the own train and another train calculated in step 1201. Further, in the case of shielding by an oncoming train, based on the track environment at the position of the on-board radio station acquired in step 1203, the oncoming train in the track environment in which the own train exists is obtained from the wireless communication quality evaluation model database 209 of FIG. The evaluation model of the influence of the shielding by the above is acquired, and the shielding attenuation amount according to the distance between the on-board radio station of the own train and the terrestrial radio station of the connection destination calculated in step 1201 is acquired.

Step 1205: The effect evaluation process 607 on the wireless communication quality due to the presence of the shield is terminated.

FIG. 13 is a diagram showing a model of shielding damping characteristics due to the presence of each of the preceding train, the following train, and the oncoming train for each track environment in the wireless train control system simulator 104 of this embodiment.

The wireless communication quality evaluation model database 209 (including the contents held in tabular form in FIG. 8) referred to inside the wireless train control system simulator 104 includes other trains (preceding train, following train, oncoming train) for each track environment. It retains the shielding attenuation characteristics (in terms of received power intensity) that model the magnitude of the effect of shielding by the train). Specifically, in order to evaluate the effect of the presence of a shield on the radio communication quality shown in FIG. 12, the relationship between the distance between the own train and the preceding train and the amount of shielding attenuation, and the own train The relationship between the distance to the following train and the amount of shielding attenuation, and the distance to the ground radio station to which the on-board radio station of the own train existing on the opposite line side of the own train and the oncoming train is connected and the amount of shielding attenuation The relationship of is maintained as a shielding damping characteristic. In general, even if the existence of a shield between the same own train and another train is assumed, the magnitude of the influence differs depending on the track environment. Therefore, even in the event-driven simulator to which the present invention is applied, the wireless communication quality evaluation model shown in FIG. It is preferable to have a model of shielding attenuation characteristics for each line environment in the database 209. The shielding damping characteristic may be changed depending on the vehicle body shape, the vehicle body cross section, and the knitting growth.

FIG. 14 is a flowchart showing the procedure of the communication error occurrence rate calculation process (609) in the wireless train control system simulator 104 of this embodiment. The operation based on the flowchart of FIG. 14 is as follows.

Step 1401: When the calculation process of the communication error occurrence rate in FIG. 6 (step 609) is started, among the wireless communication quality indexes calculated in step 608 of FIG. 6, the on-board radio station and the terrestrial radio station to which it is connected are used. The desired wave received power to interference wave power ratio (SIR) is calculated from the values of the desired wave (wireless communication for train control) and the received power intensity (RSSI) of the interference wave. In the wireless train control system simulator 104 of this embodiment, the SIR value is calculated in each of the upstream and downstream directions between the on-board radio station and the connected terrestrial radio station, and the smaller value is the relevant value. The SIR value of the control cycle evaluated by the wireless communication quality event.

Step 1402: Using the SIR value obtained in step 1401, the frame error rate (FER) of the control cycle evaluated by the radio communication quality event from the SIR-FER characteristics of the radio used in the radio train control device shown in FIG. Value) is calculated.

Step 1403: The communication error occurrence rate calculation process 609 is terminated.

FIG. 15 shows the desired wave power to interference wave power ratio (SIR) and frame error rate (FER) of the on-board and terrestrial radios used in the wireless train control system in the wireless train control system simulator 104 of this embodiment. It is a figure which shows the relationship with).

Since this SIR-FER characteristic differs depending on the radio used by the system to be evaluated in the event-driven simulator to which the present invention is applied, it is set as one of the information of the radio specification 202 of FIG. In the communication error occurrence rate calculation process 609 shown in FIG. 14, this characteristic is referred to when the FER value is acquired from the SIR value in step 1402.

FIG. 16 is a flowchart showing the procedure of the system reliability evaluation process (316) in the wireless train control system simulator 104 of this embodiment. The operation based on the flowchart of FIG. 16 is as follows.

Step 1601: When the system reliability evaluation process (step 316) in FIG. 3 starts, at each position of the on-board radio station mounted on the train traveling on the railway line to be evaluated, which is calculated in step 313 of FIG. Emergency braking of trains controlled by the wireless train control system at each position of the on-board radio station using the wireless communication quality index (including the frame error rate (FER) shown in FIG. 14 for the flow of calculation processing). Calculate the probability of occurrence. For example, the occurrence of the emergency brake evaluated as a probability in the wireless train control system simulator 104 of the present embodiment is, for example, that the wireless communication deteriorates to a predetermined condition (for example, the wireless communication is interrupted for a predetermined time and the frame error rate). The emergency brake is activated to stop the train when the train is interrupted when the value is worse than a predetermined value.

More specifically, if the communication quality is continuously poor at the evaluation time, which is the time when the predetermined number of retransmissions are executed, the value obtained by multiplying the frame error rate of each timing at which the failed retransmission is performed causes an emergency brake. Let it be a probability.

Step 1602: Based on the emergency brake occurrence probability obtained in step 1601, the reliability evaluation index of the wireless train control system for the specified period, the specified section, and the specified number of trains is calculated. The calculated reliability evaluation result is output to the table of the reliability evaluation result of the wireless communication system at the lower part of FIG. Further, it may be possible to output to a file such as CSV. In this embodiment, the emergency brake occurrence probability is adopted as the reliability evaluation index.

Step 1603: The system reliability evaluation process 316 is terminated.

As for the evaluation index of the reliability of the wireless communication system, the reliability evaluation index to be used may be changed according to the request from the system to be evaluated or the evaluator. The software of the wireless train control system simulator 104 may be configured. It is easily possible by changing.

In the above description, the wireless train control system has been exemplified as the target of the wireless communication quality evaluation and the reliability evaluation of the wireless communication system, but it can be applied to various control systems using wireless communication. Among them, the present invention is preferably applied to a control system that requires high safety and system availability such as train control. For example, it can be applied to a wireless communication quality evaluation and a wireless communication reliability evaluation in a control system of a remote-operated automatic driving vehicle that uses wireless communication for information transmission with a terrestrial radio station and an automobile. It can also be applied to control systems such as remote control systems for construction machinery and tail cordless elevators.

As described above, according to the embodiment of the present invention, it is an evaluation system (wireless train control system simulator 104) that evaluates a wireless system that performs wireless communication, and information on the wireless system to be evaluated and the wireless system. The input / output unit (communication interface 14, input interface 15, output interface) that inputs the environmental information of the wireless communication environment in which wireless communication is performed and outputs the evaluation result of wireless communication quality and the evaluation result of reliability of the wireless system. 18), a static environment evaluation model (route environment information 205, route configuration information list 701) related to static environment information including the shape of the space where wireless communication is performed, and evaluation parameters (wireless) in the static environment evaluation model. Communication quality evaluation parameter list 801), a dynamic environment evaluation model for time-varying dynamic environmental information including information on moving obstacles and moving interference wave sources (shield information 204, shielding event list), and The wireless communication quality evaluation model database 209 that stores the evaluation parameters (wireless communication quality evaluation parameter list 801) in the dynamic environment evaluation model for each wireless communication environment, and the wireless communication quality according to the position of the wireless device that performs wireless communication. The evaluation results of the wireless communication quality evaluation unit 210 and the wireless communication quality evaluation unit 210 that acquire the evaluation model and evaluation parameters required for evaluation from the wireless communication quality evaluation model database 209 and evaluate the wireless communication quality of the wireless system. Since the system reliability evaluation unit 211 that evaluates the reliability of the wireless system is provided based on the above, the wireless communication quality due to a shield or an interference wave source that temporarily appears with the passage of time in the area where wireless communication is performed. The effect on can be evaluated.

Further, since the wireless communication quality evaluation model database 209 stores the wireless communication environment, the radio wave propagation characteristics in each wireless communication environment, and the influence characteristics of the shield and the interference wave source on the wireless communication quality of the wireless system in association with each other. In railroad applications traveling in a variety of environments, entries can be used for each environment to provide appropriate evaluation according to the type of environment.

In addition, the dynamic environmental information represented by the dynamic environmental evaluation model includes the influence characteristics of trains traveling on the same route, so that the wireless system used in the railway application can be appropriately evaluated.

Further, the wireless communication quality evaluation model database 209 includes a propagation environment evaluation model relating to the shielding attenuation characteristic showing the relationship between the distance between the radio and the shield and the attenuation amount of the received power in the wireless communication, and the propagation environment evaluation. Since the evaluation parameters in the model are stored for each wireless communication environment, the characteristics of obstacles and the environment can be appropriately reflected in the simulation results.

Further, when the wireless communication quality evaluation unit 210 has a shield around the radio and the shield is closer than the connected radio connected to the wireless device, the wireless communication quality evaluation unit 210 uses the propagation environment evaluation model to attenuate the shield. Since the characteristics are evaluated, it is possible to appropriately evaluate a wireless system that can exclude obstacles that are less affected by using only the distance parameter, taking advantage of the characteristics of railway applications where the position of the shield is limited to the track. ..

Further, the wireless communication quality evaluation unit 210 uses the name of the wireless communication environment according to the position of the wireless device to obtain one or more evaluation models necessary for evaluating the wireless communication quality and the evaluation parameters in the evaluation model. Since the wireless communication quality evaluation model database 209 is collectively acquired, the wireless system can be easily evaluated for each environment.

It should be noted that the present invention is not limited to the above-mentioned examples, but includes various modifications and equivalent configurations within the scope of the attached claims. For example, the above-mentioned examples have been described in detail in order to explain the present invention in an easy-to-understand manner, and the present invention is not necessarily limited to those having all the described configurations. Further, a part of the configuration of one embodiment may be replaced with the configuration of another embodiment. Further, the configuration of another embodiment may be added to the configuration of one embodiment. In addition, other configurations may be added / deleted / replaced with respect to a part of the configurations of each embodiment.

Further, each configuration, function, processing unit, processing means, etc. described above may be realized by hardware by designing a part or all of them by, for example, an integrated circuit, and the processor realizes each function. It may be realized by software by interpreting and executing the program to be executed.

Information such as programs, tables, and files that realize each function can be stored in a storage device such as a memory, a hard disk, SSD (Solid State Drive), or a recording medium such as an IC card, SD card, DVD, or BD. can.

In addition, the control lines and information lines show what is considered necessary for explanation, and do not necessarily show all the control lines and information lines necessary for mounting. In practice, it can be considered that almost all configurations are interconnected.

101 ... wireless train control system specification information, 102 ... train operation information, 103 ... railway route information, 104 ... wireless train control system simulator, 105 ... wireless communication quality evaluation result, 106 ... system reliability evaluation result, 107 ... simulation Evaluation scenario, 108 ... Simulation evaluation scenario, 201 ... Ground radio station location information, 202 ... Radio station specifications, 203 ... handover control information, 204 ... shield information, 205 ... route environment information, 206 ... system operation simulation unit, 207 ... Train operation simulation unit, 208 ... Route environment simulation unit, 209 ... Wireless communication quality evaluation model database, 210 ... Wireless communication quality evaluation department, 211 ... System reliability evaluation department, 401 ... Graphical interface

Claims (9)

An evaluation system that evaluates wireless systems that perform wireless communication.
An input / output unit that inputs information on the wireless system to be evaluated and environmental information on the wireless communication environment in which wireless communication is performed in the wireless system, and outputs the evaluation result of wireless communication quality and the evaluation result of reliability of the wireless system. When,
A static environment evaluation model for static environment information including the shape of the space where wireless communication is performed, evaluation parameters in the static environment evaluation model, and temporally including information on moving obstacles and moving interference wave sources. A wireless communication quality evaluation model database that stores a dynamic environment evaluation model for changing dynamic environmental information and evaluation parameters in the dynamic environment evaluation model for each wireless communication environment.
Wireless communication that evaluates the wireless communication quality of the wireless system by acquiring the evaluation model and evaluation parameters required for wireless communication quality evaluation from the wireless communication quality evaluation model database according to the position of the wireless device that performs wireless communication. With the Quality Evaluation Department,
An evaluation system including a system reliability evaluation unit that evaluates the reliability of the wireless system based on the result of evaluation by the wireless communication quality evaluation unit. The evaluation system according to claim 1.
The wireless communication quality evaluation model database stores the wireless communication environment, radio propagation characteristics in each wireless communication environment, and the influence characteristics of the shield and the interference wave source on the wireless communication quality of the wireless system in association with each other. An evaluation system characterized by that. The evaluation system according to claim 1.
The evaluation system characterized in that the dynamic environmental information represented by the dynamic environmental evaluation model includes the influence characteristics of trains traveling on the same route. The evaluation system according to claim 1.
The wireless communication quality evaluation model database includes a propagation environment evaluation model relating to shielding attenuation characteristics showing the relationship between the distance between the radio and an obstruction and the attenuation of received power in the wireless communication, and the propagation environment evaluation. An evaluation system characterized by storing the evaluation parameters in the model for each wireless communication environment. The evaluation system according to claim 4.
When the shield exists around the radio and the shield is closer to the connected radio connected to the radio, the wireless communication quality evaluation unit shields the radio using the propagation environment evaluation model. An evaluation system characterized by evaluating damping characteristics. The evaluation system according to claim 1.
The wireless communication quality evaluation unit uses the name of the wireless communication environment according to the position of the wireless device to obtain one or more evaluation models necessary for evaluating the wireless communication quality and evaluation parameters in the evaluation model. An evaluation system characterized by collectively acquiring from the wireless communication quality evaluation model database. It is an evaluation method in which a computer evaluates a wireless system that performs wireless communication.
The calculator has an arithmetic unit that executes a predetermined arithmetic processing and a storage device that the arithmetic unit can access.
The storage device has a static environment evaluation model relating to static environment information including the shape of the space where wireless communication is performed, evaluation parameters in the static environment evaluation model, and information on a moving shield and a moving interference wave source. Stores a wireless communication quality evaluation model database that stores a dynamic environment evaluation model related to dynamically changing dynamic environment information including time and evaluation parameters in the dynamic environment evaluation model for each wireless communication environment.
The method is
An input procedure in which the arithmetic unit receives input of information on the wireless system to be evaluated and environmental information on the wireless communication environment in which wireless communication is performed in the wireless system.
The arithmetic unit acquires the evaluation model and evaluation parameters required for the wireless communication quality evaluation according to the position of the wireless device performing the wireless communication from the wireless communication quality evaluation model database, and obtains the wireless communication quality of the wireless system. Wireless communication quality evaluation procedure to evaluate and
A system reliability evaluation procedure in which the arithmetic unit evaluates the reliability of the wireless system based on the evaluation result of the wireless communication quality evaluation procedure.
An evaluation method, wherein the arithmetic unit includes an output procedure for outputting the evaluation result of the wireless communication quality and the evaluation result of the reliability of the wireless system. The evaluation method according to claim 7.
The wireless communication quality evaluation model database includes a propagation environment evaluation model relating to shielding attenuation characteristics showing the relationship between the distance between the radio and an obstruction and the attenuation of received power in the wireless communication, and the propagation environment evaluation. The evaluation parameters in the model are stored for each wireless communication environment,
In the wireless communication quality evaluation procedure, when the arithmetic unit has a shield around the radio and the shield is closer to the connected radio connected to the radio, the propagation environment evaluation is performed. An evaluation method characterized by evaluating the shielding attenuation characteristics using a model. The evaluation method according to claim 7.
In the wireless communication quality evaluation procedure, the arithmetic unit uses the name of the wireless communication environment according to the position of the wireless device to obtain one or more evaluation models necessary for evaluating the wireless communication quality and the evaluation model in the evaluation model. An evaluation method characterized in that evaluation parameters are collectively acquired from the wireless communication quality evaluation model database.

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