Throughput estimation device and throughput estimation method

Abstract

To estimate throughput propagation from path classification, reception power of a radio terminal every time and the number of allocation resources to a railroad radio system.SOLUTION: A throughput estimation device includes a database for respectively recording reception power, the number of allocation resources and throughput observed in the past together with date and time and a position, together with related information, a recording part for determining a propagation path classification corresponding to a position to be an estimation object, and recording information required to estimate throughput to the database on the basis of the date and time and the propagation path classification of the estimation object by updating or adding data, and an estimation part for calculating respective estimation values of the reception power and the number of allocation resources from respective past reception power and the number of past allocation resources recorded in the database every date and time and position, and a throughput estimation value from respective estimation values of the reception power and the number of allocation resources and the past throughput recorded in the database on the basis of the date and time and the propagation path classification of an estimation object.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a throughput estimation device and a throughput estimation method, mainly for railway radio systems. [Background technology]

[0002] In recent years, with the spread of networks, applications (hereafter simply referred to as "apps") and services are being provided via networks. To access these apps and services, many systems use general-purpose wireless communication systems such as LTE and 5G. One example that is currently attracting attention is the use of networked systems in railway systems, which aim to ensure safe, accurate, and comfortable train operation.

[0003] In current railway systems, in order to achieve safe, accurate, and comfortable train operation, dedicated wireless systems are used, and siloed wireless systems are built to meet the different communication requirements of each railway app. As a result, current railway systems face challenges such as high implementation and operating costs, and difficulty in linking different railway apps. Therefore, building a railway system that utilizes a general-purpose wireless communication system is expected to reduce fixed costs by becoming asset-less and zero-infrastructure.

[0004] However, using a general-purpose wireless system poses challenges, such as the need to share the network with general users and the lack of wireless coverage specifically for railways, making it impossible to guarantee that the communications requirements of railway apps will be met across the entire railway line.

[0005] In response to this, a communication platform with a communication control function that guarantees communication quality for each railway application is being considered. By implementing communication control such as utilizing multiple communication paths and transmitting redundant packets, this communication platform can meet the communication requirements of railway applications even in areas with insufficient throughput, thereby realizing the railway system described above.

[0006] As described above, in order to realize a system that utilizes a general-purpose wireless communication system, it is essential to design a system to provide appropriate applications and services, and to estimate future communication quality in order to realize dynamic communication control.

[0007] Patent Document 1 describes a technology for estimating throughput, which is one of the communication quality measures, in which a communication speed estimation device records past communication log information such as date and time and identification information for the server, network, and user terminal, and calculates actual throughput information for each server, network, and user terminal by time period based on this recorded communication log information. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent No. 6383009 Summary of the Invention [Problem to be solved by the invention]

[0009] In a general-purpose wireless system, the throughput changes independently due to changes in obstacles on the propagation path and changes in the amount of communication by wireless terminals not subject to estimation. Specifically, changes in obstacles on the propagation path change the received power and the signal-to-interference-plus-noise power ratio, which in turn changes the modulation method used in communication, thereby changing the throughput.

[0010] On the other hand, with regard to changes in communication volume by wireless terminals not subject to estimation, when the terminals present in the communication area or the traffic volume change, the number of resource blocks, which indicates the size of the wireless resources allocated to the wireless terminals subject to estimation, changes, and the throughput changes.

[0011] Therefore, the throughput is small in both environments: an environment where there are no obstructions in the propagation path and there is a large amount of communication traffic from wireless terminals not subject to estimation, and an environment where there is a small amount of communication traffic from wireless terminals not subject to estimation and there are many obstructions in the propagation path.

[0012] That is, in an environment where the surrounding environment changes significantly, such as changes in obstacles present in the propagation path or changes in the amount of communication by wireless terminals not subject to estimation, the accuracy of throughput estimation deteriorates significantly.

[0013] Existing methods estimate throughput by focusing on the characteristic that the communication volume of wireless terminals not subject to estimation changes over time. However, because they do not take into account changes in received power, they do not solve the problem of the degradation in throughput estimation accuracy mentioned above.

[0014] Therefore, the present invention has been made in consideration of the above points, and aims to provide a technology that enables throughput estimation based on propagation path classification and the received power and number of allocated resources of a wireless terminal for each time period. [Means for solving the problem]

[0015] In order to solve the above problem, one representative throughput estimation device of the present invention is a throughput estimation device for estimating the throughput of wireless communication used for mobile bodies involved in passenger transport, which provides a propagation path classification for classifying the environment of a propagation path of wireless communication, and determines a propagation path classification corresponding to a position to be estimated from a database in which the date and time and the position of the travel path of the mobile body, together with related information, actually measured past received power, actually measured past number of allocated resources, and actually measured past throughput are recorded, as well as status information related to wireless communication and operation information of the mobile body, and then calculates a propagation path classification corresponding to a position to be estimated based on the date and time to be estimated and the determined propagation path classification for the database. The data processing system includes a recording unit that records information required for estimating throughput by updating or adding data, and an estimation unit that determines a propagation path classification corresponding to a position to be estimated from status information related to wireless communication and operation information of the mobile body, and calculates estimated values ​​of received power and number of allocated resources from past received power and past numbers of allocated resources recorded in the database for each date and time and position on the mobile body's travel path based on the date and time to be estimated and the determined propagation path classification, and also calculates an estimated value of throughput from the estimated values ​​of received power and number of allocated resources and past throughput recorded in the database. [Effects of the Invention]

[0016] According to the present invention, it is possible to estimate throughput based on the received power and the number of allocated resources for the location and date and time to be estimated, so that throughput can be estimated without degrading the estimation accuracy even in an environment where there are large changes in obstructions in the propagation path or large changes in the communication volume of wireless terminals other than the target of estimation. Problems, configurations, and effects other than those described above will become apparent from the following description of the preferred embodiments. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a block diagram showing an example of the physical configuration of an entire railway system that has introduced a communication platform to which the present invention is applied. [Figure 2] 1 is a block diagram showing an example of the configuration of a railway application transmission device according to the present invention. [Figure 3] 1 is a block diagram showing an example of the configuration of a communication quality estimation device according to the present invention. [Figure 4] FIG. 10 is a diagram showing an example of an output screen from the communication quality estimation device displayed via an output interface. [Figure 5] FIG. 2 is a block diagram showing an example of the configuration of a DB recording device included in the communication quality estimation device. [Figure 6] FIG. 4 is a diagram illustrating an example of a data configuration of information required to estimate received power, the number of allocated resources, and throughput according to the first embodiment. [Figure 7] 1 is a block diagram illustrating an example of the configuration of a throughput estimation device included in a communication quality estimation device according to a first embodiment. [Figure 8] 10 is a flowchart illustrating the overall processing procedure of a received power recording unit, a throughput recording unit, or an allocated resource number recording unit included in the DB recording device of the first embodiment. FIG. [Figure 9] FIG. 10 is a flowchart showing the procedure of DB update processing shown in step S806 of FIG. 8. [Figure 10] FIG. 2 is a flowchart illustrating an overall processing procedure performed by a received power estimation unit, a throughput estimation unit, or an allocated resource number estimation unit included in the throughput estimation device of the first embodiment. [Figure 11] FIG. 11 is a flowchart showing the procedure of the estimation process shown in step S1002 of FIG. [Figure 12] FIG. 10 is a diagram illustrating an example of a data configuration of information required to estimate received power and the number of allocated resources according to the second embodiment. [Figure 13] FIG. 10 is a flowchart illustrating a procedure of DB update processing in the second embodiment. [Figure 14] FIG. 10 is a flowchart illustrating a procedure of a received power estimation process performed by a received power estimation unit according to the second embodiment. [Figure 15]FIG. 10 is a flowchart illustrating a procedure of a process for estimating the number of allocated resources performed by an allocated resource number estimating unit according to the second embodiment. [Figure 16] FIG. 11 is a block diagram showing an example of the configuration of a DB recording device included in a communication quality estimation device according to a third embodiment. [Figure 17] FIG. 11 is a flowchart illustrating an overall processing procedure of an allocated resource number recording unit according to a third embodiment. [Figure 18] FIG. 18 is a flowchart showing the procedure of the calculation process of the number of allocated resources shown in step S1701 of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, with reference to the drawings, a description will be given of Examples 1 to 3 as modes for carrying out the present invention. Note that the present invention is not limited to these Examples. In addition, in the description of the drawings, the same parts are denoted by the same reference numerals. [Example]

[0019] FIG. 1 is a block diagram showing an example of the physical configuration of the entire railway system that has introduced a communication platform to which the present invention is applied. The railway system shown in Figure 1 employs a configuration in which communications related to train operation and customer services are conducted via a general-purpose wireless system between multiple railway application devices on the moving train and on the ground, thereby providing a wireless communication system that ensures safe, accurate, and comfortable railway operation.

[0020] In a general-purpose wireless system, one or more railway application transmission devices 101 and one or more base stations 103 are installed on the ground in a communication area where service can be provided, and are connected to a network 102. A wireless terminal 104 and the railway application transmission device 101 installed on the train are connected to the base station 103 connected to the network 102. Note that in the present invention, the general-purpose wireless system is not limited to LTE or 5G as long as it is a system that can allocate transmission opportunities based on propagation path environment information and the number of resource blocks.

[0021] FIG. 2 is a block diagram showing an example of the configuration of the railway application transmission device 101 according to the present invention. The railway application transmission device 101 includes a railway application management device 201 , a communication platform 202 , and a communication quality estimation device 203 .

[0022] The railway application management device 201 is a device that transmits and receives data using communication control by the communication platform 202, and realizes train operations, customer services, and the like.

[0023] For example, in areas where throughput is insufficient, communication control by the communication platform 202 prioritizes communications related to railway applications that are important for train operation. As a result, wireless resources can be occupied, making it possible to realize safe, accurate, and comfortable train operation even in areas where throughput is insufficient.

[0024] The communication quality estimation device 203 is a device that outputs an estimated value of the communication quality of the railway application to the communication platform 202. In the present invention, the communication quality estimation device is particularly a device that estimates throughput, and the communication quality estimation device 203 has a throughput estimation device 204 and a database (DB) recording device (hereinafter referred to as "DB recording device") 205.

[0025] The throughput estimation device 204 is a device that receives recorded past wireless communication information as input and outputs a throughput estimation value.

[0026] The DB recording device 205 is a device that receives wireless communication information as input and records information required for the throughput estimation device 204 to estimate the throughput in a database (DB).

[0027] FIG. 3 is a block diagram showing an example of the configuration of the communication quality estimation device 203 according to the present invention. The communication quality estimation device 203 is configured by a computer having a processor (CPU) 301, a memory 302, an auxiliary storage device 304, a communication interface 305, an input interface 303, and an output interface 306. In Fig. 3, "interface" is abbreviated as "I / F."

[0028] The processor (CPU) 301 is a computing device that executes programs stored in the memory 302, and by executing various programs, realizes the processing of the throughput estimation device 204 and the DB recording device 205. Note that part of the processing performed by the processor (CPU) 301 by executing the programs may be executed by another computing device (for example, hardware such as an ASIC or FPGA).

[0029] The memory 302 includes a ROM, which is a non-volatile storage element, and a RAM, which is a volatile storage element. The ROM stores unchanging programs (e.g., BIOS). The RAM is a high-speed, volatile storage element such as a DRAM (Dynamic Random Access Memory), and temporarily stores programs executed by the processor 301 and data used when the programs are executed.

[0030] The auxiliary storage device 304 is a large-capacity non-volatile storage device such as a magnetic storage device (HDD) or a flash memory (SSD), and stores data used by the processor 301 when executing a program and the program executed by the processor 301. That is, the program is read from the auxiliary storage device 304, loaded into the memory 302, and executed by the processor 301 to realize each function of the communication quality estimation device 203.

[0031] The communication interface 305 is a network interface device that controls communication with other devices according to a predetermined protocol. The input interface 303 is an interface to which input devices (not shown) such as a keyboard and a mouse are connected, and which receives input from an operator.

[0032] The output interface 306 is an interface to which an output device (not shown) such as a display device is connected, and which outputs the results of the execution of the program in a format that can be viewed by an operator.

[0033] The program executed by the processor 301 is provided to the communication quality estimation device 203 via removable media (CD-ROM, flash memory, etc.) and stored in a non-volatile auxiliary storage device 304, which is a non-transitory storage medium. For this reason, the communication quality estimation device 203 should preferably have an interface for reading data from removable media.

[0034] FIG. 4 is a diagram showing an example of an output screen from the communication quality estimation device 203 displayed via the output interface 306. As an output screen, a list 402 of settings in the communication quality estimation device 203, past recorded data 414 used for estimation, and estimation results 415 of wireless communication indicators are output on a graphical interface 401.

[0035] To obtain an estimated value of throughput, each item in the setting list 402 in the communication quality estimation device 203 is set, and processing is executed using the estimation start button 413. This causes the past recorded data 414 used for estimation and the estimation result 415 to be displayed as a table or graph, respectively. As a result, it becomes possible to configure settings for communication control on the communication platform 202 side based on the information displayed in the estimation result 415 or the estimation result output via the communication interface 305.

[0036] The setting list 402 in the communication quality estimation device 203 sets the estimation time granularity 403 (for example, day, hour, and second as shown in FIG. 4 ) to be estimated, date and time 404, route 405, estimated location interval 406, wireless system 407, wireless terminal 408, and railway application 409. The setting list 402 also includes wireless communication indicators 410 that can be acquired in the railway system, received power estimation setting 411, and allocated resource number estimation setting 412 in order to determine the processing method in the communication quality estimation device 203.

[0037] The past recorded data 414 used for estimation is output as a table linking date and time with received power, a table linking date and time with the number of allocated resources, and a table linking date and time with throughput.

[0038] The estimated results 415 of the wireless communication indicators are displayed as a graph showing the train (on-board radio station) position and estimated received power in the kilometer direction (the direction the train is traveling), a graph showing the train (on-board radio station) position and estimated number of allocated resources, and a graph showing the train (on-board radio station) position and estimated throughput.

[0039] FIG. 5 is a block diagram showing an example of the configuration of the DB recording device 205 included in the communication quality estimation device 203. As shown in FIG. The DB recording device 205 is made up of a received power recording unit 503 , a throughput recording unit 504 , an allocated resource number recording unit 505 , a received power DB 506 , a throughput DB 507 and an allocated resource number DB 508 .

[0040] A received power recording unit 503 receives railway application wireless communication information 501 and train operation information 502 as input, and outputs and records information required for estimating received power in the throughput estimation device 204 to a received power DB 506 .

[0041] FIG. 6 is a diagram showing an example of data configurations 601, 602, and 603 of information required to estimate the received power, the number of allocated resources, and the throughput in the first embodiment.

[0042] 6 shows an example 601 of the data configuration of the received power DB 506 as information necessary to estimate the received power. The received power DB 506 stores the date and time, route, wireless system information, wireless terminal, and received power (actual measured value). For example, the first line of the data configuration 601 indicates that the received power of "wireless terminal X" using the wireless system "LTE" on route "Route A" on date and time "2022 / 1 / 1" is "-110 (dBm)."

[0043] The allocated resource number recording unit 505 receives the railway application wireless communication information 501 and the train operation information 502 as input, and outputs and records information required for the throughput estimation device 204 to estimate the allocated resource number to the allocated resource number DB 508 .

[0044] 6 shows an example 602 of the data configuration of the number of allocated resources DB 508 as information necessary to estimate the number of allocated resources. The number of allocated resources DB 508 stores the date and time, route, wireless terminal, wireless system information, type of railway app, transmission direction, and number of allocated resources (actual measured value). For example, the first line of the data configuration 602 indicates that the number of resources allocated to "wireless terminal X," which transmits the railway app "Train Control" using the wireless system "LTE" present on the route "Route A" in the "Down Link" direction on the date and time "2022 / 1 / 1," is "10."

[0045] The throughput recording unit 504 receives as input the railway application wireless communication information 501, the train operation information 502, the received power linked to the date and time output from the received power recording unit 503, and the number of allocated resources linked to the date and time output from the allocated resource number recording unit 505, and outputs and records the information necessary for the throughput estimation device 204 to the throughput DB 507.

[0046] The bottom part of Figure 6 shows an example 603 of the data configuration of the throughput DB 507, which is information necessary to estimate the throughput. The throughput DB 507 stores the date and time, route, wireless terminal, wireless system information, type of railway app, transmission direction, received power, number of allocated resources, and throughput (actual measured value). For example, the first line of the data configuration 603 indicates that, on the date and time "2022 / 1 / 1", the received power of "wireless terminal X" transmitting the railway app "train control" using the wireless system "LTE" present on route "Route A" is "-110 (dBm)", the number of allocated resources is "10", and the throughput is "0.03 M (bps)".

[0047] Here, the railway application wireless communication information 501 and the train operation information 502 will be described. The railway application wireless communication information 501 is information that is collected at specified time intervals and includes the location, date and time, terminal type, transmission direction, wireless system information, received power, number of allocated resources, and throughput. The source of the date and time, terminal type, transmission direction, wireless system information, received power, number of allocated resources, and throughput is not particularly limited. For example, the information may be issued from the railway application transmission device 101 or the wireless terminal 104. The source of the location is also not particularly limited. For example, the information may be issued from a GPS device, a physical location on the rail read from a sensor, or train schedule information, which is the train operation information 502.

[0048] The train operation information 502 is information that collects geographical information of railway lines, train schedule information, and passenger occupancy rates. Note that the source of the geographical information and train schedule information is not particularly limited. For example, it may be a system that manages railway operations.

[0049] The route information recorded in the received power DB 506, the throughput DB 507, and the number of allocated resources DB 508 is an example of an index for classifying propagation paths. Therefore, other classifications may be used. For example, propagation scenarios classified by communication area, cell ID, or population density may be used.

[0050] FIG. 7 is a block diagram showing an example of the configuration of the throughput estimation device 204 included in the communication quality estimation device 203 according to the first embodiment. The throughput estimation device 204 includes a received power estimation unit 701 , a throughput estimation unit 703 , a number of allocated resources estimation unit 702 , a received power DB 506 , a throughput DB 507 , and a number of allocated resources DB 508 .

[0051] The received power estimation unit 701 receives as input the railway application wireless communication information 501, the train operation information 502, and the received power information linked to the required date and time output from the received power DB 506, and outputs an estimated value of the received power to the throughput estimation unit 703.

[0052] The allocated resource number estimation unit 702 receives as input the railway application wireless communication information 501, the train operation information 502, and the allocated resource number information linked to the required date and time output from the allocated resource number DB 508, and outputs an estimated value of the allocated resource number to the throughput estimation unit 703.

[0053] The throughput estimation unit 703 receives as input the railway application wireless communication information 501, the train operation information 502, the estimated value of the received power output from the received power estimation unit 701, the estimated value of the number of allocated resources output from the allocated resource number estimation unit 702, and the throughput information linked to the required date and time extracted from the throughput DB 507, and outputs an estimated value of the throughput.

[0054] 8 is a flowchart showing the overall processing procedure performed by the received power recording unit 503, the throughput recording unit 504, or the number of allocated resources recording unit 505 of the DB recording device 205 of the first embodiment. The operation of each processing step will be described below, but since the main operator is either the received power recording unit 503, the throughput recording unit 504, or the number of allocated resources recording unit 505, a description of the main operator in each processing step will be omitted.

[0055] Step S801: Railway application wireless communication information associated with the date, time, and location to be estimated is acquired from the railway application transmission device 101 or the wireless terminal 104. The type of information to be acquired depends on the data structure stored in each DB (received power DB 506, throughput DB 507, or allocated resource number DB 508). For example, in the case of the received power recording unit 503, the date, time, route, wireless system information, wireless terminal, and received power are acquired as the railway application wireless communication information 501 in this step.

[0056] Step S802: Train operation information, such as geographical information about the railway line, train position information, and propagation path environment information, is acquired from a system related to railway operation.

[0057] Step S803: Based on steps S801 and S802, the propagation path classification of the position to be estimated is determined. Here, propagation path classification refers to classifying the propagation path environment. For example, it classifies the location of the estimation target at a granularity such as the name of the line or whether it is rural, urban, or built-up. As a result, even if data of the same propagation path classification has not been recorded in the past, it is possible to estimate the throughput using data of a propagation path classification that is close to the propagation path environment. Note that the propagation path classification may be determined in advance for each railway line, or may be determined by comparing the train schedule with the time associated with the acquired data.

[0058] Step S804: The information acquired in step S801 is processed so as to be stored in each DB (received power DB 506, throughput DB 507, or allocated resource number DB 508). Specifically, the number of decimal places and units are adjusted. For example, since the received power value of the data acquired in step S801 is "-112.34", if the received power DB 506 has a rule for recording as an integer value, the received power value is rounded down to "-112".

[0059] Step S805: Search whether there is past data recorded in each DB (received power DB 506, throughput DB 507, or allocated resource number DB 508) that matches the date and time and propagation path classification of the data processed in step S804. If there is matching data (yes), proceed to step S806; if there is no matching data (no), proceed to step S807.

[0060] Step S806: Each DB (received power DB 506, throughput DB 507, or allocated resource number DB 508) is updated using the date and time of the data processed in step S804 and information corresponding to the propagation path classification.

[0061] Step S807: An area for storing the data processed in step S804 is secured in each DB (received power DB 506, throughput DB 507, or allocated resource number DB 508).

[0062] Step S808: The data processed in step S804 is added to each DB (received power DB 506, throughput DB 507, or allocated resource number DB 508).

[0063] Fig. 9 is a flowchart showing the procedure of the DB update process shown in step S806 in Fig. 8. The operation mode of each processing step will be explained below, but since the main operator is either the received power recording unit 503, the throughput recording unit 504, or the number of allocated resources recording unit 505, a description of the main operator in each processing step will be omitted.

[0064] Step S901: The data on the date and time to be updated and the propagation path classification recorded in each DB (received power DB 506, throughput DB 507, or number of allocated resources DB 508) are extracted, and the minimum values ​​of the received power, throughput, and number of allocated resources to be estimated (hereinafter, collectively referred to as "wireless communication indexes") are obtained.

[0065] Step S902: The minimum value of the wireless communication index acquired in step S901 is compared with the actual measurement data of the wireless communication index processed in step S804 of Fig. 8. If the processed data is smaller than the minimum value (yes), the process proceeds to step S903; if it is larger (no), the process proceeds to step S904.

[0066] Step S903: The data recorded in each DB (received power DB 506, throughput DB 507, and allocated resource number DB 508) is updated to the actual measurement data processed in step S804 of FIG.

[0067] Step S904: The actual measurement data processed in step S804 is discarded without being updated.

[0068] 10 is a flowchart illustrating the overall processing procedure of the received power estimation unit 701, the throughput estimation unit 703, or the number of allocated resources estimation unit 702 included in the throughput estimation device 204 of the first embodiment. Hereinafter, the operation mode of each processing step will be described. However, since the main operator is either the received power estimation unit 701, the throughput estimation unit 703, or the number of allocated resources estimation unit 702, the description of the main operator in each processing step will be omitted. In addition, since the first three processing steps are the same as the first three processing steps (S801 to S803) of the flowchart shown in FIG. 8, the description thereof will also be omitted.

[0069] Step S1001: Search for past data recorded in each DB (received power DB 506, throughput DB 507, or allocated resource number DB 508) that matches the data date and time and propagation path classification. If matching data is found (yes), proceed to step S1002; if matching data is not found (no), proceed to step S1004.

[0070] Step S1002: Based on past data recorded in each DB (received power DB 506, throughput DB 507, and allocated resource number DB 508), an estimated value of the received power, the number of allocated resources, or the throughput is acquired. This estimation process will be described later with reference to FIG.

[0071] Step S1003: The estimated value of the received power, the number of allocated resources, or the throughput acquired in step S1002 is output.

[0072] Step S1004: Determine whether it is possible to broaden the designated range of the propagation path classification determined in step S803. If it is possible to broaden the designated range of the propagation path classification (yes), proceed to step S1005; if it is not possible (no), proceed to step S1006.

[0073] Here, broadening the range of the propagation path classification designation means, for example, if the propagation path classification information in step S803 is "Route A" and "Urban", and no corresponding information exists in each DB in step S1001, removing the "Urban" condition and attempting to execute step S1001 again with only "Route A" as the condition.

[0074] As a result, while the estimation accuracy deteriorates, it is possible to estimate throughput even for routes or environments for which no past data exists. The extent to which the range of the propagation path classification specification can be expanded depends on the data configuration recorded in each DB (received power DB 506, throughput DB 507, or allocated resource number DB 508).

[0075] Step S1005: The designated range of the propagation path classification to be designated is updated to be wider. Step S1006: Since throughput estimation is impossible even through the processing steps up to step S1006, a result indicating that estimation is impossible is output.

[0076] Fig. 11 is a flowchart showing the procedure of the estimation process shown in step S1002 of Fig. 10. The operation mode of each processing step will be explained below, but since the main operator is either the received power estimation unit 701, the throughput estimation unit 703, or the number of allocated resources estimation unit 702, a description of the main operator in each processing step will be omitted.

[0077] Step S1101: Information that matches the date and time and propagation path classification to be estimated is obtained from each DB (received power DB 506, throughput DB 507, or allocated resource number DB 508).

[0078] Step S1102: From the data extracted in step S1101, the minimum value of the received power, the throughput, or the number of allocated resources is obtained, and this value is used as the estimated value.

[0079] The above describes, as the first embodiment, an example of processing for estimating the following three items when the time unit for estimating throughput for the purpose of designing a railway system using a general-purpose wireless system is set to one day. The received power estimation unit 701 estimates the received power from information related to the received power recorded in the past, using the railway application wireless communication information 501, the train operation information 502, and the received power DB 506. The allocated resource number estimation unit 702 estimates the number of allocated resources from information related to the number of allocated resources recorded in the past, using the railway application wireless communication information 501, the train operation information 502, and the allocated resource number DB 508. The throughput estimation unit 703 estimates the throughput from the estimated values ​​of the received power and the number of allocated resources, information related to throughput recorded in the past in the throughput DB 507, the railway application wireless communication information 501, and the train operation information 502.

[0080] In the first embodiment, the throughput can be estimated by taking into consideration the propagation path environment, which is a factor of the surrounding environment that affects the throughput, and the change in the communication volume of wireless terminals that are not the subject of estimation, as changes in the received power and the number of allocated resources.

[0081] This allows throughput to be achieved without a deterioration in estimation accuracy even in an environment where changes in obstructions in the propagation path or large changes in communication volume by wireless terminals other than the estimation target occur. Also, by recording data in the received power DB 506, throughput DB 507, and number of allocated resources DB 508, and each wireless communication index with different time-varying granularity, as separate DBs and using them for estimation, it becomes possible to update data to follow changes in the surrounding environment.

[0082] Although the first embodiment uses the received power as an index indicating the environment information of the propagation path, other indexes indicating the environment information of the propagation path may be used, such as the signal-to-interference-plus-noise power ratio (SINR), the channel quality index (CQI), or the modulation and coding scheme (MCS). [Example]

[0083] Next, a second embodiment of the present invention will be described. However, the description of the second embodiment will focus on differences from the first embodiment. The second embodiment is similar to the first embodiment unless otherwise specified. Example 2 also assumes the estimation of throughput for the purpose of operating a railway system utilizing a general-purpose wireless system, but shows an example in which the time unit to be estimated is a finer time unit (for example, seconds) than the day unit used in Example 1.

[0084] In the first embodiment, if there is no propagation path classification to be estimated in step S1001 shown in FIG. 10, an output indicating that estimation is impossible is made (step S1006). However, in the second embodiment, it is assumed that the information required for throughput estimation on all routes has already been distributed as part of the system design.

[0085] FIG. 12 is a diagram illustrating an example of a data configuration 1201 and 1202 of information required to estimate the received power and the number of allocated resources in the second embodiment.

[0086] 12 shows an example 1201 of the data configuration of the received power DB 506 as information necessary to estimate the received power. The received power DB 506 stores the date and time, route, wireless system information, wireless terminal, actually measured received power, an outlier determination flag, and the minimum value of the received power over the past T hours. For example, the first line of the data configuration 1201 indicates that at the date and time "2022 / 1 / 1 12:00", the actually measured received power of "wireless terminal X" using the wireless system "LTE" on route "Route A" was an "outlier" of "-110 (dBm)", and the minimum value of the received power over the past T hours was "-110 (dBm)".

[0087] 12 shows an example data configuration 1202 of the allocated resource number DB 508 as information necessary to estimate the number of allocated resources. The allocated resource number DB 508 stores the date and time, route, wireless terminal, wireless system information, type of railway app, transmission direction, occupancy rate, actual measured value of the number of allocated resources, outlier determination flag, and minimum value of the number of allocated resources. For example, the first row of the data configuration 1202 indicates that at the date and time "2022 / 1 / 1 12:00", for "wireless terminal X" which is present on route "route A" and transmits the railway app "train control" using the wireless system "LTE" and has an occupancy rate of "10%, " the actual measured value of the number of allocated resources is an "outlier" of "10", and the minimum value of the number of allocated resources is 20.

[0088] In addition to the time and propagation path classification that take into account the influence of the surrounding environment, the data stored in each DB may also include surrounding environmental information. Weather information for the propagation path, event information at nearby facilities, and information on train delays may also be recorded.

[0089] Here, the outlier determination flag is a value indicating whether or not the actual measured values ​​of received power or number of allocated resources recorded in the past T hours are outliers. By using only the actual measured values ​​for which the outlier determination flag is not an outlier to estimate received power and number of allocated resources, it is possible to eliminate the influence of the area with the worst wireless communication index within the propagation environment to be estimated and the influence of temporary deterioration in communication quality. Furthermore, since only the actual measured values ​​for which the outlier determination flag is not an outlier are used for estimating throughput, a similar effect can be obtained, and it is possible to improve the availability of communication control by the communication platform 202.

[0090] The outlier determination flag may be set not based on the past T hours but also based on whether it is a weekday or a holiday, or on the day of the week. In this case, calendar information (e.g., day of the week information, weekday or holiday identification information, etc.) is additionally recorded to the date and time information recorded in the received power DB 506, throughput DB 507, and allocated resource number DB 508.

[0091] In the second embodiment, the overall processing procedure by the received power recording unit 503, the throughput recording unit 504, or the number of allocated resources recording unit 505 included in the DB recording device 205 is the same as that shown in the flowchart of Fig. 8 described in the first embodiment, but the DB update processing in step S806 is different. The DB update processing in the second embodiment will be described below.

[0092] Fig. 13 is a flowchart showing the procedure of DB update processing in the second embodiment, which corresponds to step S806 in Fig. 8. The operation mode of each processing step will be described below, but since the main operator is either the received power recording unit 503, the throughput recording unit 504, or the allocated resource count recording unit 505, a description of the main operator in each processing step will be omitted.

[0093] Step S1301: From the propagation path classifications recorded in each DB (received power DB 506, throughput DB 507, or number of allocated resources DB 508), extract the data that corresponds to the date and time to be updated in the past T hours, and obtain the wireless communication indicator (received power, throughput, or number of allocated resources).

[0094] Step S1302: Statistical processing is performed to determine whether each value of the wireless communication index acquired in step S1301 is an outlier. Examples of statistical processing for determining whether each value is an outlier include methods using the interquartile range or the Smirnoff-Grubbs test, but any method may be used.

[0095] Step S1303: Among the values ​​of the wireless communication indicators acquired in step S1301, the minimum value of the wireless communication indicators (received power, throughput, or number of allocated resources) that are not outliers is acquired.

[0096] Step S1304: If the actual measurement value processed in step S804 shown in FIG. 8 is not an outlier as a result of the outlier determination in step S1302 (no), proceed to step S1305; if it is an outlier (yes), proceed to step S1307.

[0097] Step S1305: Compare the minimum value acquired in step S1303 with the data processed in step S804. If the processed data is smaller than the minimum value (yes), proceed to step S1306; if it is larger (no), proceed to step S1307.

[0098] Step S1306: The data recorded in each DB (received power DB 506, throughput DB 507, or allocated resource number DB 508) is updated based on the data processed in step S804 (FIG. 8) and the outlier determination result in step S1302.

[0099] Step S1307: The data in each DB is updated using the minimum value acquired in step S1303.

[0100] 14 is a flowchart illustrating the procedure of the received power estimation process 1002 performed by the received power estimation unit 701 according to the second embodiment. The operation of each processing step will be described below, but since the main operator is the received power estimation unit 701, the description of the main operator in each processing step will be omitted.

[0101] Step S1401: The received power associated with the date, time, and location is acquired from the railway application transmission device 101 or the wireless terminal 104.

[0102] Step S1402: Data relating to the received power of the propagation path classification to be estimated for the past T hours before the estimation target date and time is obtained from the received power DB 506.

[0103] Step S1403: The minimum value of the received power is obtained from the data obtained in step S1402.

[0104] Step S1404: The received power acquired in step S1401 is compared with the received power at the time closest to the time of the received power acquired in step S1401 from the data related to the received power acquired in step S1402, and the error rate between the two is acquired as a correction coefficient.

[0105] Step S1405: The minimum value of the received power acquired in step S1403 is corrected using the correction coefficient (error rate) acquired in step S1404, and the corrected value is acquired as an estimated value.

[0106] 15 is a flowchart illustrating the procedure of the allocated resource number estimation process 1002 performed by the allocated resource number estimation unit 702 according to the second embodiment. The operation of each processing step will be described below, but since the operating entity is the allocated resource number estimation unit 702, the operating entity in each processing step will not be described.

[0107] Step S1501: The passenger occupancy rate of the train carrying the wireless terminal to be estimated is obtained from a railway operation system (not shown).

[0108] Step S1502: Data on the number of allocated resources of the propagation path classification to be estimated during the past T hours from the estimated target date and time is obtained from the allocated resource number DB 508.

[0109] Step S1503: The occupancy rate acquired in step S1501 is compared with the occupancy rate in the past data of the allocated resource number DB 508 acquired in step S1502, and a determination is made as to whether or not the occupancy rates are the same. For this determination, for example, the occupancy rates of the data group acquired in step S1501 may be subjected to the statistical processing for outlier determination shown in the previous step S1302 (FIG. 13) to determine whether or not they are outliers. If the result of the determination is that the occupancy rate is the same as the past data (yes), the process proceeds to step S1505, and if the occupancy rate is not the same as the past data (no), the process proceeds to step S1504.

[0110] Step S1504: Data of another propagation path classification to be estimated for the past T hours before the estimation target date and time, which differs from the data acquired in step S1502, is acquired from the number of allocated resources DB 508. For example, if the data differs from the past data of the propagation path environment of "Route A", it is sufficient to acquire the past data of the propagation path environment of "Route B".

[0111] Step S1505: The minimum value of the number of allocated resources is obtained from the data obtained in step S1502 or step S1504, and this value is used as an estimated value.

[0112] As described above, the second embodiment is characterized in that it determines whether or not an outlier is present and records the result as a DB update process (step S806) for the received power DB 506, the throughput DB 507, and the number of allocated resources DB 508. This allows the granularity of the date and time to be estimated to be finer than in the first embodiment, thereby improving the availability of railway applications that are affected by instantaneous degradation of communication quality.

[0113] In the second embodiment, the received power estimation unit 701 estimates the received power using a correction coefficient obtained from the past received power and the received power associated with the date, time, and location to be estimated. Furthermore, in the second embodiment, the allocated resource number estimation unit 702 estimates the number of allocated resources using the occupancy rate to be estimated and the past occupancy rate. As a result, even if the information required for throughput estimation at the location and time to be estimated is insufficient, it is possible to estimate the throughput with high accuracy.

[0114] Furthermore, in the second embodiment, a method using outliers is adopted for the DB update process (step S806), but this is not limited to this method. In order to take into account the influence of changes in the data characteristics of received power, the number of allocated resources, and throughput, weights are assigned to data close to the date and time (time) of the estimation target. A method can be used in which statistical processing taking this weighting into consideration (for example, taking a moving average with a larger weight for the most recent data) and acquiring the statistically processed value as the estimated value. [Example]

[0115] Next, a third embodiment of the present invention will be described. However, the description of the third embodiment will focus on differences from the first embodiment. The aspects of the third embodiment that are not particularly mentioned are the same as those of the first embodiment. The third embodiment deals with a case where the number of allocated resources cannot be collected from a wireless terminal in a railway system.

[0116] FIG. 16 is a block diagram showing an example of the configuration of the DB recording device 205 included in the communication quality estimation device 203 according to the third embodiment. The DB recording device 205 of the third embodiment has the same components as those of the first embodiment, but the input information and functions of the allocated resource count recording unit 1602 are different. The functions of the other components, the DBs, and the data configurations recorded in the DBs are the same as those of the first embodiment.

[0117] The allocated resource number recording unit 1602 receives the railway application wireless communication information 501, the train operation information 502, and the throughput information from the throughput DB 507 as input, and outputs and records information required for the throughput estimation device 204 to estimate the number of allocated resources in the allocated resource number DB 508.

[0118] Fig. 17 is a flowchart illustrating the overall processing procedure of the allocated resource number recording unit 1602 of the embodiment 3. The difference from the flowchart of the embodiment 1 (where the allocated resource number recording unit 1602 is the main operator) shown in Fig. 8 is that step S1701 is added between step S803 and step S804.

[0119] In the added step S1701, the allocated resource number recording unit 1602 calculates the number of allocated resources from the data acquired in step S801.

[0120] Fig. 18 is a flowchart showing the procedure for the calculation process of the number of allocated resources shown in step S1701 of Fig. 17. This flowchart shows two types of calculation process of the number of allocated resources: a method of calculating the number of allocated resources from wireless communication indicators other than the number of allocated resources, and a case where wireless communication indicators other than the number of allocated resources cannot be obtained. Below, the operation mode of each processing step will be explained, but since the operator is the number of allocated resources recording unit 1602, the operator in each processing step will not be described.

[0121] Step S1801: Obtain actual measured throughput from the railway application wireless communication information 501 Step S1802: In the railway system, it is determined whether it is possible to acquire physical layer indicators related to wireless communication. Here, physical layer indicators related to wireless communication refer to MCS, modulation method, number of layers, etc. If the result of this determination is yes, proceed to step S1803; if not (no), proceed to step S1805.

[0122] Step S1803: The railway application transmission device 101 or the wireless terminal 104 acquires a physical layer index related to wireless communication.

[0123] Step S1804: The number of allocated resources is obtained. Specifically, the throughput can be calculated by multiplying the number of allocated resources, the parameters of the MCS, modulation method, and number of layers, and a constant determined by the wireless system. Therefore, the number of allocated resources is calculated by taking the ratio of the actually measured throughput to the sum of all the above parameters and the above constant. Note that the calculation is possible even if any of the parameters of the MCS, modulation method, and number of layers is missing.

[0124] Step S1805: The maximum value of the throughput of the propagation path classification to be estimated during the past T hours from the estimation target date and time is obtained from the throughput DB 507.

[0125] Step S1806: The number of resources to be allocated is calculated by taking the ratio between the actual throughput acquired in step S1801 and the maximum throughput acquired in step S1805.

[0126] As described above, in the third embodiment, even if the number of allocated resources cannot be collected from the wireless terminal as a railway system, it is possible to obtain the number of allocated resources and estimate the throughput even if physical layer indicators related to other wireless communication can be obtained or even if these indicators cannot be obtained.

[0127] However, the present invention is not limited to the railway systems described in the first to third embodiments. For example, the present invention can also be applied to a system for a moving object that moves along a predetermined route according to a schedule.

[0128] Although the first to third embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit and scope of the present invention. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, part of the configuration of one embodiment may be replaced with the configuration of another embodiment, or the configuration of another embodiment may be added to the configuration of one embodiment. Furthermore, part of the configuration of each embodiment may be added to, deleted from, or replaced with other configurations. Furthermore, although various information has been exemplified in a table format, this information may also be managed in a format other than a table. [Explanation of symbols]

[0129] 101...railway application transmission device, 103...base station, 104...wireless terminal, 201...Railway application management device, 202...Communication platform, 203...communication quality estimation device, 204...throughput estimation device, 205...DB recording device, 301...Processor (CPU), 302...Memory, 303...Input 1 / F, 304... Auxiliary storage device, 305... Communication I / F, 306... Output I / F, 501...Railway application wireless communication information, 502...Train operation information, 503...Receiving power recording unit, 504...throughput recording unit, 505, 1602...allocated resource number recording unit, 506...received power DB, 507...throughput DB, 508...allocated resource number DB, 701...received power estimation unit, 702...allocated resource number estimation unit, 703...Throughput estimation unit

Claims

1. A throughput estimation device that estimates a throughput of wireless communication used for a moving object related to passenger transportation, comprising: providing a propagation path classification for classifying an environment of the propagation path of the wireless communication; a database in which the past measured received power, the past measured number of allocated resources, and the past measured throughput are recorded together with relevant information, along with the date and time and the location of the travel path of the mobile unit; a recording unit that determines the propagation path classification corresponding to the location to be estimated from the state information related to the wireless communication and the operation information of the mobile body, and records information required to estimate throughput in the database by updating or adding data based on the date and time of the estimation target and the determined propagation path classification; an estimation unit that determines the propagation path classification corresponding to a position to be estimated from status information related to the wireless communication and operation information of the mobile body, and calculates estimated values ​​of each of the received power and the number of allocated resources from the past received power and the past number of allocated resources recorded in the database for each date and time and position on the traveling path of the mobile body based on the date and time to be estimated and the determined propagation path classification, and also calculates an estimated value of throughput from the estimated values ​​of each of the received power and the number of allocated resources and the past throughput recorded in the database; A throughput estimation device comprising:

2. 2. The throughput estimation device according to claim 1, The database, the recording unit, and the estimation unit are provided individually for the received power, the number of allocated resources, and the throughput, respectively. A throughput estimation device characterized by:

3. 3. The throughput estimation device according to claim 1, The date and time recorded in the database is information having a granularity suited to the purpose of obtaining each of the estimated values. A throughput estimation device characterized by:

4. 3. The throughput estimation device according to claim 1, The date and time recorded in the database includes information on the day of the week or information identifying weekdays and holidays. A throughput estimation device characterized by:

5. 3. The throughput estimation device according to claim 1, the propagation path classification has classification information with different granularities, The estimation unit, when calculating the estimated value, changes the granularity in accordance with the determined propagation path classification to calculate the estimated value. A throughput estimation device characterized by:

6. 3. The throughput estimation device according to claim 1, the database further records, as the related information of the actually measured past received power, a determination flag indicating whether or not the actually measured past received power is an outlier, and as the related information of the actually measured past number of allocated resources, a determination flag indicating whether or not the actually measured past number of allocated resources is an outlier; The recording unit updates the data for the data of the received power and the data of the number of allocated resources recorded in the database, for which the determination flag is not the outlier. A throughput estimation device characterized by:

7. 7. The throughput estimation device according to claim 6, The estimation unit uses data of the received power and data of the allocated resource number, the determination flag of which is not an outlier and which is recorded in the database, when calculating estimated values ​​of the received power, the number of allocated resources, and the throughput. A throughput estimation device characterized by:

8. 7. The throughput estimation device according to claim 6, The estimation unit compares the occupancy rate of the mobile body to be estimated with the past occupancy rate included in the information related to the actually measured past number of allocated resources recorded in the database, and if the two are different, calculates an estimate of the number of allocated resources using another propagation path classification different from the propagation path classification. A throughput estimation device characterized by:

9. 7. The throughput estimation device according to claim 6, The estimation unit corrects the estimated value of the received power by using, as a correction coefficient, an error rate between the received power at the date and time of the estimation target and the location of the estimation target and the actually measured past received power recorded in the database. A throughput estimation device characterized by:

10. 3. The throughput estimation device according to claim 1, The estimation unit weights data of the received power, the number of allocated resources, and the throughput recorded in the database that is closest to the date and time of the estimation target, and obtains estimated values ​​of the received power, the number of allocated resources, and the throughput through statistical processing that takes the weighting into consideration. A throughput estimation device characterized by:

11. 3. The throughput estimation device according to claim 1, When the number of allocated resources cannot be obtained by actual measurement, the recording unit calculates the number of allocated resources using the actually measured throughput and various parameters that are indicators of a physical layer related to the wireless communication, and uses the calculated value when updating or adding data to the database. A throughput estimation device characterized by:

12. 3. The throughput estimation device according to claim 1, The wireless communication used for the mobile body related to the passenger transport is the wireless communication of the railway system using general-purpose wireless. A throughput estimation device characterized by:

13. A throughput estimation method for estimating a throughput of wireless communication used for a moving object related to passenger transportation, comprising: providing a propagation path classification for classifying an environment of the propagation path of the wireless communication; providing a database in which the past measured received power, the past measured number of allocated resources, and the past measured throughput are recorded together with relevant information, along with the date and time and the position of the travel path of the mobile body; a recording step of determining the propagation path classification corresponding to the location to be estimated from the status information related to the wireless communication and the operation information of the mobile body, and recording information required to estimate throughput in the database by updating or adding data based on the date and time of the estimation target and the determined propagation path classification; an estimation step of determining the propagation path classification corresponding to a position to be estimated from status information related to the wireless communication and operation information of the mobile body, and calculating estimated values ​​of each of the received power and the number of allocated resources from the past received power and the past number of allocated resources recorded in the database for each date and time and position on the traveling path of the mobile body based on the date and time to be estimated and the determined propagation path classification, and calculating an estimated value of throughput from the estimated values ​​of each of the received power and the number of allocated resources and the past throughput recorded in the database; A throughput estimation method having:

14. 14. The throughput estimation method according to claim 13, further recording, in the database, a determination flag indicating whether the actually measured past received power is an outlier or not as the related information of the actually measured past received power, and a determination flag indicating whether the actually measured past number of allocated resources is an outlier or not as the related information of the actually measured past number of allocated resources; In the recording step, the data update is performed on data of the received power and the number of allocated resources recorded in the database, the data for which the determination flag is not the outlier. A throughput estimation method comprising:

15. 14. The throughput estimation method according to claim 13, When the number of allocated resources cannot be obtained by actual measurement, In the recording step, a calculated value of the number of allocated resources is obtained using various parameters that are indices of the physical layer related to the wireless communication and the actually measured throughput, and the calculated value is used when updating or adding data to the database. A throughput estimation method comprising:

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