Communication quality estimation device and communication control device

Abstract

The objective is to provide a communication system, communication device, and communication method that perform communication control to avoid or suppress the effects of communication quality degradation due to handover. [Solution] The system comprises a communication quality estimation device that estimates communication quality taking into account the effects of handover processing and reconnection processing after handover, and a communication control device that performs communication control to avoid or suppress the effects of deterioration of communication quality due to handover processing and reconnection processing after handover, based on the communication quality estimated by the communication quality estimation device.

Description

Technical Field

[0001] The present invention relates to a communication system, a communication device, and a communication method, and more particularly to a communication system, a communication device, and a communication method that perform communication control considering the influence of communication quality degradation due to handover.

Background Art

[0002] Handover refers to an operation of switching the base station for communication when communicating with a wireless terminal equipped in a mobile body. When performing handover, communication quality may deteriorate due to handover processing and reconnection processing after handover.

[0003] For example, Patent Document 1 describes a technique aimed at providing information necessary for determining whether a position where wireless communication is performed is an unstable area where switching of a base station device may occur, as a radio wave map. Specifically, Patent Document 1 includes a radio wave map storage unit that stores a radio wave map including reference position information indicating a reference position, communication speeds between a plurality of external communication devices at the reference position, and connection probabilities that are probabilities of performing wireless communication with each of the plurality of external communication devices at the reference position, a reception unit that receives a radio wave map request including request position information indicating a requested position, a minimum guaranteed speed calculation unit that obtains a minimum guaranteed speed at the reference position based on the communication speed and the connection probability, an estimated speed calculation unit that obtains an estimated speed at the reference position based on the communication speed and the connection probability, an unstable area determination unit that determines whether the reference position is an unstable area based on the connection probability, and a transmission unit that transmits a radio wave map reply including the connection probability, the minimum guaranteed speed, the estimated speed, and information indicating whether the reference position is an unstable area at the reference position corresponding to the request position information. A radio wave map providing device having the above components is disclosed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

[0005] Patent Document 1 identifies an unstable region as one where communication instability may occur based on the connection probability with multiple external communication devices at the terminal location. It then calculates a minimum guaranteed speed and an estimated speed based on the communication speed and connection probability with each of the multiple external communication devices, and performs communication control based on these calculation results. However, the minimum guaranteed speed and estimated speed evaluate the communication speed in the steady state after the handover process and the reconnection process after the handover are completed, and do not evaluate the impact of the handover process and the reconnection process after the handover on communication quality. Therefore, it has been difficult to implement communication control that avoids or suppresses the effects of communication quality degradation caused by the handover process and the reconnection process after the handover in the unstable region.

[0006] In view of the above problems, the present invention aims to provide a communication system, communication device, and communication method that perform communication control to avoid or suppress the effects of communication quality degradation due to handover. [Means for solving the problem]

[0007] To achieve the above objective, one representative communication system of the present invention is characterized by comprising: a communication quality estimation device that estimates communication quality taking into account the effects of handover processing and reconnection processing after handover; and a communication control device that performs communication control to avoid or suppress the effects of deterioration of communication quality due to handover processing and reconnection processing after handover based on the communication quality estimated by the communication quality estimation device.

[0008] Furthermore, one communication method of the present invention is characterized by including a communication quality estimation step in which a communication quality estimation device estimates the communication quality taking into account the effects of handover processing and reconnection processing after handover, and a communication control step in which a communication control device performs communication control to avoid or suppress the effects of deterioration of communication quality due to handover processing and reconnection processing after handover, based on the communication quality estimated in the communication quality estimation step. [Effects of the Invention]

[0009] According to the present invention, communication control can be performed in communication systems, communication devices, and communication methods to avoid or suppress the effects of handover-induced deterioration of communication quality. Other issues, configurations, and effects will be clarified by the following embodiments. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a block diagram showing the configuration of one embodiment of the communication system of the present invention. [Figure 2] Figure 2 is a block diagram showing an example of the configuration of a communication control device in the communication system of the present invention. [Figure 3] Figure 3 is a block diagram showing an example of the configuration of a communication quality estimation device in the communication system of the present invention. [Figure 4] Figure 4 is a block diagram showing an example of the hardware configuration of a communication control device in the communication system of the present invention. [Figure 5] Figure 5 is a block diagram showing an example of the hardware configuration of a communication quality estimation device in the communication system of the present invention. [Figure 6] Figure 6 shows an example of the period during which communication quality degradation occurs due to handover when a mobile object is moving (traveling). [Figure 7] Figure 7 is a flowchart showing an example of the process for generating a communication quality evaluation model in the communication system of the present invention. [Figure 8]FIG. 8 is a flowchart showing an example of communication quality estimation processing in the communication system of the present invention. [Figure 9] FIG. 9 is a diagram showing a configuration example of a communication quality evaluation model list in the communication system of the present invention. [Figure 10] FIG. 10 is a flowchart showing an example of communication control setting processing in the communication system of the present invention. [Figure 11] FIG. 11 is a flowchart showing an example of communication control method selection processing in the communication system of Example 1. [Figure 12] FIG. 12 is a diagram showing a configuration example of a communication path list in the communication system of the present invention. [Figure 13] FIG. 13 is a diagram showing a configuration example of an application list in the communication system of the present invention. [Figure 14] FIG. 14 is a diagram showing a configuration example of a communication path list used for each application in the communication system of the present invention. [Figure 15] FIG. 15 is a flowchart showing an example of communication control method selection processing in the communication system of Example 2. [Figure 16] FIG. 16 is a diagram showing a configuration example of a communication path list used for each application in the communication system of Example 2. [Figure 17] FIG. 17 is a diagram explaining a method for avoiding or suppressing the influence of communication quality deterioration of an application due to handover in the communication system of Example 3. [Figure 18] FIG. 18 is a flowchart showing an example of communication control method selection processing in the communication system of Example 3. [Figure 19] FIG. 19 is a diagram showing a configuration example of a communication quality evaluation model list in the communication system of Example 4.

Embodiments for Carrying Out the Invention

[0011] Embodiments for carrying out the present invention will be described.

[0012] <Block Diagram> FIG. 1 is a block diagram showing the configuration of an embodiment of the communication system of the present invention.

[0013] The communication system shown in FIG. 1 includes a communication control device 103, a communication quality estimation device 104, a server-side application terminal 101, a communication platform 102, a first mobile carrier network 105, a second mobile carrier network 110, a communication platform 115, and an edge-side application terminal 116.

[0014] Here, the communication platform 115 and the edge-side application terminal 116 are provided in the mobile body. Further, the communication control device 103, the communication quality estimation device 104, the server-side application terminal 101, and the communication platform 102 are installed at a location other than the mobile body, such as on the ground side. The mobile body is an object that moves, such as a railway, a vehicle, a bus, an airplane, a ship, an automated guided vehicle, etc. The mobile body is particularly suitable for application to a mobile body that runs in the same place, for example, a train running on a track.

[0015] In FIG. 1, the server-side application terminal 101 is denoted as "app_center1", the communication platform 102 is denoted as "pf_center1", the communication platform 115 is denoted as "pf_edge1", and the edge-side application terminal 116 is denoted as "app_edge1". Also, the first mobile carrier can also be represented as "MNO1", and the second mobile carrier can also be represented as "MNO2".

[0016] The communication control device 103 is a device that controls the communication platforms 102 and 115. The communication control device 103 is connected to the communication platform 102, and can control the communication platform 115 via the first mobile carrier network 105 or the second mobile carrier network 110. The communication control device 103 generates and manages communication control settings for each application in order to avoid or suppress the influence of communication quality degradation of the application due to handover between the server-side application terminal 101 and the edge-side application terminal 116.

[0017] The impact of handover on application communication quality degradation includes the degradation caused by the handover process itself and the reconnection process after the handover. The handover process is the process of switching to an adjacent cell. The reconnection process after the handover is the process of reconnecting if the handover process fails due to congestion or other reasons related to communication.

[0018] The communication quality estimation device 104 estimates the communication quality of the application, taking into account the effects of handover, in response to a request from the communication control device 103.

[0019] In Figure 1, the first mobile carrier network 105 and the second mobile carrier network 110 are used between the server-side application terminal 101 and the edge-side (mobile-side) application terminal 116. Mobile carrier networks 105 and 110 represent their respective communication paths. A communication path represents, for example, a contracted mobile carrier network, and each mobile carrier network is configured to communicate independently. Therefore, even if it is the same carrier, if the configuration allows for independent communication, it can be identified as each mobile carrier network (communication path). The wireless system may be changed as long as it is the same communication path. For example, it may be changed from LTE (Long Term Evolution) to 5G (5th Generation). The edge-side application terminal 116 can be used to control mobile devices using an application. In this case, since safety and reliability are required, it is desirable to have multiple communication paths as shown in Figure 1.

[0020] On the first mobile carrier network 105, there exists a first core network 106, a first radio access network 107, a first radio base station 108, and a first radio terminal 109. Similarly, on the second mobile carrier network 110, there exists a second core network 111, a second radio access network 112, a second radio base station 113, and a second radio terminal 114. This configuration enables communication between the communication platform 102 and the mobile device's communication platform 115. The first radio terminal 109 and the second radio terminal 114 are installed on the mobile device.

[0021] Figure 2 is a block diagram showing an example of the configuration of the communication control device 103 of the communication system of the present invention. In Figure 2, the internal configuration of the communication control device 103 shown in Figure 1 will be explained in terms of functional blocks.

[0022] The communication control device 103 includes an application DB 201, a communication channel DB 202, a communication control setting DB 204, a mobile information DB 206, a communication control setting generation unit 203, and a communication control setting management unit 205.

[0023] The application DB 201 is a database that holds information about applications that utilize communication between the server-side application terminal 101 and the edge-side application terminal 116. This application information includes details such as the application ID, communication interval, and communication requirements. The applications are used with communication platforms 102 and 115 to avoid or mitigate the impact of communication quality degradation due to handover.

[0024] The communication channel DB202 is a database that holds information about communication channels available to communication platforms 102 and 115. This communication channel information includes, for example, the communication channel ID, communication carrier, communication system, and communication section.

[0025] The communication control settings DB204 is a database that holds communication control setting information for each application on the communication platforms 102 and 115.

[0026] The mobile device information DB206 is a database that holds information about mobile devices carrying edge-side wireless terminals 109 and 114, edge-side communication platform 115, and edge-side application terminal 116. Here, information about mobile devices includes, for example, mobile device ID, route information, and wireless terminal placement information.

[0027] The communication control setting generation unit 203 makes a communication quality estimation request to the communication quality estimation device 104 based on the mobile location information obtained from the mobile information DB 206 and the communication channel information obtained from the communication channel DB 202. The communication quality estimation request is made for each application stored in the application DB 201. Here, the communication quality estimation request is a request for communication quality estimation that takes into account the impact of handover on the deterioration of the application's communication quality. Subsequently, using the communication quality estimation results obtained from the communication quality estimation device 104, the unit generates a communication control setting that avoids or suppresses the impact of handover on the deterioration of the application's communication quality and satisfies the application's communication requirements. The generated communication control setting is stored in the communication control setting DB 204.

[0028] The communication control setting management unit 205 retrieves the communication control settings determined by the communication control setting generation unit 203, which are stored in the communication control setting DB 204. The communication control setting management unit 205 then transfers and applies the retrieved communication control settings to the communication platforms 102 and 115. Here, the communication control settings are the communication control settings between each application and the communication platforms 102 and 115.

[0029] Figure 3 is a block diagram showing an example of the configuration of the communication quality estimation device 104 in the communication system of the present invention. In Figure 3, the internal configuration of the communication quality estimation device 104 shown in Figure 1 will be explained in terms of functional blocks.

[0030] The communication quality estimation device 104 includes a communication quality evaluation model DB 302, a communication quality estimation unit 301, a measurement information receiving unit 303, and a communication quality evaluation model generation unit 304.

[0031] The communication quality evaluation model DB302 is a database that holds the communication quality evaluation model. The communication quality evaluation model is a model for estimating communication quality, taking into account the impact of communication quality degradation due to handover, for applications that use communication between the server-side application terminal 101 and the edge-side application terminal 116.

[0032] The communication quality estimation unit 301 receives a communication quality estimation request from the communication control device 103 and obtains a communication quality evaluation model from the communication quality evaluation model DB 302. Here, the communication quality evaluation model holds information such as the location of the handover process and the reconnection process after the handover in the communication channel to be evaluated. The communication quality evaluation model obtained is based on information such as the location information of the mobile object, communication channel information, and time information. The obtained communication quality evaluation model is transmitted to the communication control device 103 as a response to the communication quality estimation request.

[0033] The measurement information receiving unit 303 receives communication quality measurement information from the communication platforms 102 and 115, and the wireless terminals 109 and 114. Here, the communication quality measurement information is used to generate a communication quality evaluation model that takes into account the effects of handover. The received communication quality measurement information is transmitted to the communication quality evaluation model generation unit 304.

[0034] The communication quality evaluation model generation unit 304 determines the locations where handover processing and post-handover reconnection processing occur based on the communication quality measurement information received in chronological order from the measurement information reception unit 303. If handover processing and post-handover reconnection processing occur, the communication quality evaluation model generation unit 304 records measurement data for the period during which the communication quality of the application deteriorates. The measurement data is used to update the communication quality evaluation model. Based on the recorded measurement data, the communication quality evaluation model generation unit 304 generates and updates a communication quality evaluation model for each handover processing location and stores it in the communication quality evaluation model DB 302.

[0035] <Hardware Configuration> Figure 4 is a block diagram showing an example of the hardware configuration of the communication control device 103 in the communication system of the present invention.

[0036] In this embodiment, the communication control device 103 in the communication platform is composed of a computer having a processor 401, memory 402, auxiliary storage device 404, and communication interface 405. The communication control device 103 may also have an input interface 403 and an output interface 406.

[0037] The processor 401 is an arithmetic unit that executes programs stored in the memory 402. By executing various programs, the processor 401 enables the functions of each part of the communication control device 103 (for example, the communication control setting generation unit 203, the communication control setting management unit 205, etc.). Note that some of the processing performed by the processor 401 when executing programs may be performed by other arithmetic units. The processor 401 can be a CPU (Central Processing Unit), etc. In addition, other arithmetic units such as ASICs (Application Specific Integrated Circuits) and FPGAs (Field Programmable Gate Arrays) can be used.

[0038] Memory 402 includes a non-volatile memory element called ROM and a volatile memory element called RAM. ROM stores immutable programs (e.g., BIOS (Basic Input Output System)). RAM is a high-speed, volatile memory element such as DRAM (Dynamic Random Access Memory) and temporarily stores programs executed by the processor 401 and data used during program execution.

[0039] The auxiliary storage device 404 is a high-capacity, non-volatile storage device such as a magnetic storage device (HDD) or flash memory (SSD). The auxiliary storage device 404 also stores data used by the processor 401 when executing programs (for example, application DB 201, communication channel DB 202, communication control setting DB 204, mobile information DB 206, etc.), and programs executed by the processor 401. In other words, programs are read from the auxiliary storage device 404, loaded into memory 402, and executed by the processor 401 to realize the various functions of the communication control device 103.

[0040] The communication interface 405 is a network interface device that controls communication with other devices according to a predetermined protocol.

[0041] The input interface 403 is an interface to which input devices such as a keyboard 407 and a mouse 408 are connected and to receive input from the operator. The output interface 406 is an interface to which output devices such as a display device 409 and a printer (not shown) are connected and to output the program execution results in a format that the operator can see. In addition, a user terminal connected to the communication control device 103 via a network may provide the input and output devices. In this case, the communication control device 103 may have the functionality of a web server, and the user terminal may access the communication control device 103 using a predetermined protocol.

[0042] The program executed by the processor 401 is provided to the communication control device 103 via removable media (such as a CD-ROM or flash memory) or a network, and stored in the non-volatile auxiliary storage device 404, which is a non-temporary storage medium. For this reason, the communication control device 103 is preferably provided with an interface for reading data from the removable media.

[0043] The communication control device 103 is a computer system that operates on a single physical computer or on multiple logically or physically configured computers, and may operate on a virtual computer built on multiple physical computer resources. For example, the communication control setting generation unit 203 and the communication control setting management unit 205 may each operate on separate physical or logical computers, or multiple units may be combined and operate on a single physical or logical computer.

[0044] Figure 5 is a block diagram showing an example of the hardware configuration of the communication quality estimation device 104 of the communication system according to the present invention.

[0045] In this embodiment of the communication platform, the communication quality estimation device 104 is comprised of a computer having a processor 501, memory 502, auxiliary storage device 504, and communication interface 505. The communication quality estimation device 104 may also have an input interface 503 and an output interface 506.

[0046] The processor 501 is an arithmetic unit that executes programs stored in the memory 502. By executing various programs, the processor 501 enables the functions of each part of the communication quality estimation device 104 (for example, the communication quality estimation unit 301, the measurement information receiving unit 302, the communication quality evaluation model generation unit 304, etc.). Note that some of the processing performed by the processor 501 when executing programs may be performed by other arithmetic units. The processor 401 can be a CPU or the like. In addition, hardware such as ASICs and FPGAs can be used as other arithmetic units.

[0047] Memory 502 includes a non-volatile memory element called ROM and a volatile memory element called RAM. ROM stores immutable programs (e.g., BIOS). RAM is a high-speed, volatile memory element such as DRAM, and temporarily stores programs executed by the processor 501 and data used during program execution.

[0048] The auxiliary storage device 504 is a high-capacity, non-volatile storage device such as a magnetic storage device (HDD) or flash memory (SSD). The auxiliary storage device 504 also stores data used by the processor 501 when executing a program (for example, the communication quality evaluation model DB302) and the program executed by the processor 501. In other words, the program is read from the auxiliary storage device 504, loaded into memory 502, and executed by the processor 501, thereby realizing each function of the communication quality estimation device 104.

[0049] The communication interface 505 is a network interface device that controls communication with other devices according to a predetermined protocol.

[0050] The input interface 503 is an interface to which input devices such as a keyboard 507 and a mouse 508 are connected and to receive input from the operator. The output interface 506 is an interface to which output devices such as a display device 509 and a printer (not shown) are connected and to output the program execution results in a format that the operator can see. In addition, a user terminal connected to the communication quality estimation device 104 via a network may provide the input and output devices. In this case, the communication quality estimation device 104 may have the functionality of a web server, and the user terminal may access the communication quality estimation device 104 using a predetermined protocol.

[0051] The program executed by the processor 501 is provided to the communication quality estimation device 104 via removable media (such as a CD-ROM or flash memory) or a network, and is stored in the non-volatile auxiliary storage device 504, which is a non-temporary storage medium. For this reason, the communication quality estimation device 104 is preferably provided with an interface for reading data from the removable media.

[0052] The communication quality estimation device 104 is a computer system that operates on a single physical computer or on multiple logically or physically configured computers, and may operate on a virtual computer built on multiple physical computer resources. For example, the communication quality estimation unit 301, the measurement information receiving unit 302, and the communication quality evaluation model generation unit 304 may each operate on separate physical or logical computers, or multiple units may be combined and operate on a single physical or logical computer.

[0053] <An example of the period of communication quality degradation due to handover> Figure 6 shows an example of the period during which communication quality degradation occurs due to handover when a mobile object is moving (traveling).

[0054] Figure 6 uses a train traveling on a railway line as an example of a moving object. Other moving objects such as cars, aircraft, ships, and automated guided vehicles may also be considered.

[0055] When train 610 travels from station A 601 to station B 602, the wireless base station to which train 610 is connected switches as train 610 progresses. This process of switching the connected cell is called a handover. When a handover occurs, a handover process and a reconnection process after the handover are required to establish a transmission path from the original base station to the new base station. As a result, there is a period when the transmission of application data is temporarily interrupted. Consequently, the communication quality of the application may also temporarily deteriorate.

[0056] In Figure 6, throughput is used as an indicator of the application's communication quality. It can be seen that throughput decreases around the time of handover when the destination base station ID changes. For example, when the destination base station ID changes from #11 to #12, period A is the period of communication quality degradation. Also, when the destination base station ID changes from #14 to #15, period C is the period of communication quality degradation. On the other hand, when the destination base station ID changes to #12 and #13, the processing of #13 takes time, and communication is restored after reconnection processing at #14. In this case, the period of communication quality degradation is period B.

[0057] <Communication Quality Evaluation Modeling Process> Figure 7 is a flowchart illustrating an example of the process for generating a communication quality evaluation model in the communication system of the present invention. Figure 7 is a flowchart illustrating an example of the process procedure for generating a communication quality evaluation model from communication quality measurement information from wireless terminals 109 and 114 and the communication platform 102. Here, the impact of handover processing and reconnection processing after handover on the communication quality of the application is considered.

[0058] The operation based on the flowchart shown in Figure 7 is as follows. The processing here is performed by the communication quality estimation device 104.

[0059] First, in step 701, the process of generating a communication quality evaluation model is initiated.

[0060] Next, in step 702, the measurement information receiving unit 303 acquires communication quality measurement information from the communication platforms 102 and 115, and the wireless terminals 109 and 114. The acquisition of communication quality measurement information is performed by transmitting the communication quality measurement information using the communication path between the measurement information receiving unit 303 and the communication platforms 102 and 115 via the wireless terminals 109 and 114. The communication quality measurement information includes information on the communication channel to be measured, communication quality information, measurement time information, and mobile location information at the time of measurement. Here, the information on the communication channel to be measured includes information such as the communication channel identifier, communication carrier, communication system, and destination base station identifier. The communication quality information includes information such as throughput, delay, jitter, and packet error rate.

[0061] Next, in step 703, measurement time information is obtained from the communication quality measurement information received in step 702.

[0062] Next, in step 704, the telecommunications carrier information of the target communication channel is obtained from the communication quality measurement information received in step 702.

[0063] Next, in step 705, communication system information for the target communication channel is obtained from the communication quality measurement information received in step 702. The communication system information includes information on the type of wireless system. Examples of wireless system types include LTE and 5G.

[0064] Next, in step 706, the destination base station identifiers for the wireless terminals 109 and 114 are obtained from the communication quality measurement information received in step 702. If the communication system is a 3GPP (Third Generation Partnership Project) network such as LTE or 5G, the destination base station identifiers are PCI (Physical Cell Identifier), ECGI (EUTRA Cell Global Identifier), NCGI (NR Cell Global Identifier), etc.

[0065] Next, in step 707, it is determined whether the communication quality measurement information received in step 702 is the first measurement information. If it is the first measurement information, the process proceeds to step 715. Otherwise, the process proceeds to step 708.

[0066] In step 708, the nearest connected base station identifier for the same communication system of the same communication carrier for wireless terminals 109 and 114 is obtained from the communication carrier information obtained in step 704 and the communication system information obtained in step 705. The same communication system of the same communication carrier indicates that it is the same mobile carrier network. For example, in Figure 1, this would be the first mobile carrier network 105 and the second mobile carrier network 110.

[0067] Next, in step 709, it is determined whether there has been a change in the destination base station identifiers of the current and most recent wireless terminals 109 and 114, which were obtained in steps 706 and 708, respectively. If there has been a change, the process proceeds to step 710. Otherwise, the process proceeds to step 711. In other words, if there has been a change in the destination base station identifier within the same mobile carrier network, it indicates that a new handover will occur. On the other hand, if there has been no change in the destination base station identifier, it indicates that no new handover will occur.

[0068] Step 710 records the start time of the period during which communication quality degradation occurs due to the handover process and the reconnection process after the handover. Communication quality degradation can be defined in advance by setting a numerical threshold for communication quality degradation. Since Step 710 occurs when there is a change in the destination base station identifier, it is assumed that a new handover will occur. The start time when the criteria for communication quality degradation are reached is then recorded. Here, the evaluation of communication quality degradation can be performed for each application. After Step 710, the process transitions to Step 715.

[0069] Step 711 determines whether the communication quality information in the communication quality measurement information indicates a degraded state of communication quality for the application. If it indicates a degraded state of communication quality, the process proceeds to step 715. Otherwise, the process proceeds to step 712. A degraded state of communication quality is a state that falls below the communication quality requirements, and the same criteria as for the degraded communication quality in step 710 can be used.

[0070] In step 712, the end time of the period during which communication quality degradation occurs due to the handover process and the reconnection process after the handover is recorded. Here, since it is determined in step 711 that the communication quality degradation state has ended, the end time of the period during which communication quality degradation occurs is recorded.

[0071] Next, in step 713, the period during which communication quality degradation occurs, recorded in steps 710 and 712 respectively, is calculated using the difference between the start time and the end time. The communication quality measurement information received within the calculated period is used as the target data for model updating.

[0072] Next, in step 714, a communication quality evaluation model is generated and updated based on the communication quality measurement information received during the period affected by the communication quality degradation calculated in step 713. The generated and updated communication quality evaluation model is stored in the communication quality evaluation model DB 302 by the communication quality evaluation model generation unit 304. An example of the list of communication evaluation models to be stored in the communication quality evaluation model DB 302 will be described later in Figure 9. After step 714, the process proceeds to step 715.

[0073] In step 715, it is determined whether to terminate the acquisition of communication quality measurement information from the communication platforms 102 and 115 and the wireless terminals 109 and 114 at the measurement information receiving unit 303. If the acquisition of communication quality measurement information is terminated, the process proceeds to step 716. Otherwise, the process proceeds to step 702 to receive the next communication quality measurement information.

[0074] Step 716 terminates the process of generating the communication quality evaluation model.

[0075] In this way, based on the communication quality measurement information received from the communication platforms 102, 115 and wireless terminals 109, 114 via the measurement information receiving unit 303, a communication quality evaluation model can be generated and updated for each handover point to evaluate the impact of handover processing and post-handover reconnection processing on the communication quality of the application. This makes it possible to evaluate communication quality based on a communication quality evaluation model that takes into account the different characteristics of communication quality degradation at each handover point. In other words, a mobile device equipped with a wireless terminal can pass through a handover point in advance, and the communication quality evaluation model can be generated and updated using data measured to determine the impact of communication quality degradation due to handover processing and post-handover reconnection processing.

[0076] <Communication Quality Estimation Process> Figure 8 is a flowchart illustrating an example of the communication quality estimation process in the communication system of the present invention. The communication quality estimation process estimates the communication quality based on the travel section of the mobile body, communication channel information, and time information, taking into account the impact of handover on the deterioration of the application's communication quality. Here, the impact of handover processing and post-handover reconnection processing on the deterioration of the application's communication quality is considered.

[0077] The operation based on the flowchart shown in Figure 8 is as follows. The processing here is performed by the communication quality estimation device 104.

[0078] First, in step 801, the communication quality estimation process is initiated.

[0079] Next, in step 802, the communication quality estimation unit 301 obtains travel section information of the mobile device equipped with the communication platform 115 and edge-side application terminal 116 from the communication control device 103.

[0080] Next, in step 803, the communication quality estimation unit 301 obtains information about the communication channels used between the mobile device and the ground from the communication control device 103. In Figure 1, these communication channels correspond to the mobile carrier networks 105 and 110.

[0081] Next, in step 804, the communication quality estimation unit 301 obtains information about the time period to be evaluated from the communication control device 103.

[0082] Next, in step 805, based on the mobile unit's travel section information acquired in step 802 and the communication channel information acquired in step 803, information on handover points located within the travel section when performing communication using this communication channel is obtained from the communication quality evaluation model DB302. The information on handover points is information from the communication quality evaluation model DB302 acquired and stored in the communication quality evaluation modeling process shown in Figure 7, and includes information on the point (location) where the handover occurred.

[0083] Next, in step 806, the system determines whether or not there are any handover points within the travel section based on the handover point information obtained in step 805. If there is one or more handover points within the travel section, the system proceeds to step 807. Otherwise, the system proceeds to step 811.

[0084] In step 807, based on the handover point information obtained in step 805, the information of the originating base station identifier for each handover point is obtained from the communication quality evaluation model DB302. The information of the originating base station identifier is the information in the communication quality evaluation model DB302 obtained and stored in the communication quality evaluation modeling process shown in Figure 7. The originating base station identifier is the information of the base station identifier for the cell before the switchover occurred when the handover took place.

[0085] Next, in step 808, based on the information of the handover point obtained in step 805, information on the handover destination base station identifier for each handover point is obtained from the communication quality evaluation model DB302. The information on the handover destination base station identifier is the information in the communication quality evaluation model DB302 obtained and stored in the communication quality evaluation modeling process shown in Figure 7. The handover destination base station identifier is the information on the base station identifier for the cell after the switchover occurs.

[0086] Next, in step 809, a communication quality evaluation model is obtained to evaluate the impact of handover on the communication quality of the application during the time period and on the communication channel, based on the information of the handover location obtained in step 805, the handover source base station identifier obtained in step 807, and the handover destination base station identifier obtained in step 808. This information of the handover location, handover source base station identifier, and handover destination base station identifier is obtained from the communication quality evaluation model DB302.

[0087] Next, in step 810, the communication quality evaluation model for each time zone, communication channel, and handover point acquired in step 809 is transmitted to the communication control device 103.

[0088] Next, in step 811, the communication quality estimation process is terminated.

[0089] In this way, the communication quality estimation device 104 obtains information on the time period, the mobile vehicle's travel section, and the handover location in the communication path from the communication quality evaluation model DB302, as specified by the communication control device 103. In this case, the information in the communication quality evaluation model DB302 is stored in the communication quality evaluation model information generated and updated by the communication quality modeling process shown in Figure 7. The communication quality estimation device 104 then obtains a communication quality evaluation model for each handover location and time period to evaluate the impact of the handover process and the reconnection process after handover on the application's communication quality. The communication quality estimation device 104 then transmits the obtained communication quality evaluation model to the communication control device 103. The communication control device 103 determines a communication control method to avoid or suppress that impact. As a result, the communication control device 103 can perform evaluations that take into account the impact of the handover process and the reconnection process after handover, which differ depending on the mobile vehicle's travel section, communication path, and time period, on the application's communication quality.

[0090] <List of Communication Quality Evaluation Models> Figure 9 shows an example of the configuration of a communication quality evaluation model list in the communication system of the present invention. A communication quality evaluation model list is created for each communication channel.

[0091] The upper part of Figure 9 shows the communication quality evaluation model list 901 for downlink communication, and the lower part shows the communication quality evaluation model list 902 for uplink communication. Here, "downlink" indicates the communication direction toward the mobile object, and "uplink" indicates the communication direction from the mobile object (the same applies to Figures 12-14, 16, and 19 thereafter). These communication quality evaluation model lists are stored in the communication quality evaluation model DB 302 in the communication quality estimation device 104.

[0092] The Downlink Communication Quality Evaluation Model List 901 contains information on handover processing and information on communication quality characteristics affected by handover for each handover point. Specifically, the information on handover processing is shown in Figure 9, including the handover point, the originating base station identifier, the destination base station identifier, the transition system, and the train speed. In addition, the information on communication quality characteristics is shown in Figure 9, including the throughput degradation period model. The throughput degradation period model shows the probability distribution of communication interruption time (the period during which communication quality degradation occurs) for each time of day (morning, noon, and night). This probability distribution takes into account measurement results from the train being measured, such as the number of passengers on the train and the train speed. As a result, by using a threshold that identifies a value above a predetermined probability, the period during which communication quality degradation occurs can be identified. Furthermore, since the throughput degradation period model may have different characteristics depending on the range of train (mobile object) speed, it may be divided into multiple predetermined speed ranges. In Figure 9, it is divided into cases where the speed is slower than 60 km / h and cases where it is 60 km / h or higher.

[0093] The communication quality evaluation model list 902 for uplink communication has the same configuration as the communication quality evaluation model list 901 for downlink communication. Generally, when a mobile object passes through a certain handover point, the impact of the handover process and the reconnection process after the handover on communication quality differs between downlink and uplink communication. Therefore, as shown in Figure 9, a communication quality evaluation model list is maintained for each communication direction.

[0094] <Communication control setting process> Figure 10 is a flowchart illustrating an example of the communication control setting process in the communication system of the present invention. The communication control setting process, as shown in Figure 10, generates communication control settings for each application based on information about the travel section and travel time of the mobile body, to avoid or suppress the impact of handover on the deterioration of the application's communication quality, and reflects these settings on the communication platform. Here, the impact of handover processing and reconnection processing after handover on the deterioration of the application's communication quality is considered.

[0095] The operation based on the flowchart shown in Figure 10 is as follows. The processing here is performed by the communication control device 103.

[0096] First, in step 1001, the communication control setting process is initiated.

[0097] Next, in step 1002, information about the application for which communication control settings are to be generated is obtained from the application DB201. The application information includes information about the application's communication intervals. An example of the list of application information obtained from the application DB201 will be shown later in Figure 13.

[0098] Next, in step 1003, the time information for which communication control settings are generated is obtained from the mobile information DB206, based on information regarding the movement of the mobile object.

[0099] Next, in step 1004, a list of available normal paths between communication platforms 102 and 115 is obtained from the communication path DB 202 based on the communication section information of the application for which communication control settings are to be generated, which was obtained in step 1002. An example of the list of communication paths obtained from the communication path DB 202 will be described later in Figure 12.

[0100] Next, in step 1005, a list of travel sections for the mobile objects for which communication control settings will be generated is obtained from the mobile object information DB206, based on information regarding the movement of the mobile objects.

[0101] Next, in step 1006, for each of the list of travel segments of the mobile body obtained in step 1005, communication control settings are made to avoid or suppress the impact on communication quality due to handover. If there are any travel segments that have not been set in the communication control settings, the process proceeds to step 1007. Otherwise, the process proceeds to step 1009.

[0102] In step 1007, the communication control setting generation unit 203 selects a communication control setting for the travel section where no communication control setting has been set. This selection is based on the communication quality estimation results obtained from the communication quality estimation device 104, and selects a communication control that avoids or suppresses the impact on communication quality due to handover. The details of the selected communication control will be described later in Figures 11, 15, 18, etc.

[0103] Next, in step 1008, information regarding the next travel section is obtained from the mobile information DB206, and the process returns to step 1005. Since the communication control settings for one travel section were completed in step 1007, the process returns to step 1005 to consider the next travel section.

[0104] In step 1009, the generated communication control settings are stored in the communication control settings DB204.

[0105] Next, in step 1010, the communication control setting management unit 205 retrieves the communication control settings stored in step 1009 and transmits them to the communication platforms 102 and 115. The transmitted communication control settings are reflected in the operation of the communication platforms 102 and 115 as control settings related to the application's communication.

[0106] Step 1011 terminates the communication control setting process.

[0107] In this manner, the communication control device 103 generates communication control settings in the communication control setting generation unit 203 that can avoid or suppress the impact of handover on the communication quality of the application, based on information about the travel section, time period, and available communication channel candidates of the mobile object to be evaluated. The generated communication control settings are stored in the communication control setting DB 204 and then transmitted to the communication platforms 102 and 115 via the communication control setting management unit 205. The transmitted communication control settings are then reflected in the communication control on the communication platforms 102 and 115. This enables communication control that avoids or suppresses the deterioration of the communication quality of the application caused by handover processing and reconnection processing after handover.

[0108] <Communication control method selection process in Example 1> Figure 11 is a flowchart illustrating an example of the communication control method selection process in the communication system of Example 1. The communication control method selection process in Example 1 performs a communication quality estimation for each candidate communication channel, including the impact of handover on the degradation of the application's communication quality. Based on information about the application using the communication system, the travel section of the mobile vehicle, and the travel time, it determines a communication channel that can avoid or suppress the impact of handover on the application's communication quality degradation during the application, the travel section of the mobile vehicle, and the travel time. Here, the impact of handover processing and reconnection processing after handover on the application's communication quality is considered.

[0109] The operation based on the flowchart shown in Figure 11 is as follows. The processing here is performed by the communication control device 103.

[0110] First, in step 1101, the communication control method selection process is initiated.

[0111] Next, in step 1102, a list of candidate communication channels to be used for application communication is obtained from the communication channel DB202.

[0112] Next, in step 1103, it is determined whether there are any unevaluated candidates among the list of candidate communication channels obtained in step 1102 that can achieve the communication quality required for use as a communication channel by the application. If there are unevaluated candidates, the process proceeds to step 1104. Otherwise, the process proceeds to step 1108.

[0113] In step 1104, the communication quality of the unevaluated communication channel selected in step 1103 is estimated. Specifically, the communication control setting generation unit 203 requests the communication quality estimation device 104 to estimate the communication quality, taking into account the travel section, time period, and application information of the mobile object to be evaluated, as well as the impact of handovers on candidate communication channels. Subsequently, the communication quality estimation results are obtained from the communication quality estimation device 104.

[0114] Next, in step 1105, based on the communication quality estimation results obtained in step 1104, it is evaluated whether the period affected by the degradation of communication quality due to handover on the communication channel under evaluation is less than or equal to the application's acceptable time for communication quality degradation. Here, the application's acceptable time for communication quality degradation is obtained from the application DB201. Evaluation based on the application's acceptable time for communication quality degradation can also be evaluated using information on other communication quality degradation that the application tolerates. For example, instead of the acceptable time for communication quality degradation in Figure 11, evaluation may be performed using general communication quality evaluation indicators such as throughput, latency, and packet loss rate.

[0115] If the period affected by the degradation of communication quality due to the acquired handover is less than or equal to the application's acceptable time for communication quality degradation, proceed to step 1107. Otherwise, proceed to step 1106.

[0116] In step 1106, information on the next candidate communication channel to be evaluated is obtained from the communication channel DB202. After that, the process returns to step 1103.

[0117] In step 1107, the communication channel selected in step 1105 is determined to be the communication channel to be used within the evaluation section. The selected communication channel is one that satisfies the requirements for the allowable time of communication quality degradation of the application selected in step 1105, considering the evaluation application, the mobile vehicle's travel section, and the time period. This communication channel is used for communication between communication platforms 102 and 115. The process then proceeds to step 1109.

[0118] In step 1108, it is determined that there are no usable communication channels because none of the candidate communication channels obtained in step 1102 satisfy the requirement for the application's acceptable time for degradation of communication quality. The process then proceeds to step 1109.

[0119] Next, in step 1109, the communication control method selection process is terminated.

[0120] Thus, in Embodiment 1, the communication control device 103, in the communication control setting generation unit 203, selects a communication path in which the application will not be affected by the deterioration of communication quality due to handover in the travel section and time period of the mobile object under evaluation. This selection of the communication path is performed based on the communication quality estimation results obtained from the communication quality estimation device 104, which take into account the impact of handover for each candidate communication path of the application. This enables communication control that avoids or suppresses the deterioration of the application's communication quality caused by handover processing and reconnection processing after handover.

[0121] <List of communication channels> Figure 12 shows an example of the configuration of a communication channel list in the communication system of the present invention. Figure 12 shows an example of the configuration of a communication channel list that stores communication channel information usable for downlink and uplink communication between communication platforms. The upper part of Figure 12 shows the downlink communication channel list 1201, and the lower part shows the uplink communication channel list 1202. The downlink communication channel list 1201 and the uplink communication channel list 1202 are stored in the communication channel DB 202 of the communication control device 103.

[0122] The downlink channel list 1201 consists of a channel identifier and information about the channel. In Figure 12, the channel ID is shown as the channel identifier. In Figure 12, the information about the channel includes the telecommunications carrier, communication system, source PF (platform), and destination PF (platform). The downlink channel list 1201 in Figure 12 shows an example with information on two channels, "MNO1-LTE-DOWN" and "MNO2-5G-DOWN," provided by telecommunications carriers "MNO1" and "MNO2."

[0123] The uplink communication channel list 1202 has the same configuration as the downlink communication channel list 1201. Figure 12 shows an example of the downlink communication channel list 1201 which contains information on two communication channels, "MNO1-LTE-UP" and "MNO2-5G-UP," provided by the communication carriers "MNO1" and "MNO2." Since there may be communication channels that can only be used for downlink communication or only for uplink communication among the communication channels used between communication platforms 102 and 115, a channel list is maintained separately for each communication direction, as shown in Figure 12.

[0124] <Application List> Figure 13 shows an example of the configuration of an application list in the communication system of the present invention. The application list is a list that stores the communication section and communication requirements for each application. The upper part of Figure 13 shows the downlink communication application list 1301, and the lower part shows the uplink communication application list 1302. The downlink communication application list 1301 and the uplink communication application list 1302 are stored in the application DB 201 of the communication control device 103.

[0125] The downlink application list 1301 consists of an application identifier, information about the application, and information about the degradation of communication quality due to handover that the application tolerates. In Figure 13, the application ID is shown as the application identifier. In Figure 13, the source application terminal and destination application terminal are shown as the information about the application. In Figure 13, the allowable time for communication quality degradation is shown as the information about the degradation of communication quality that the application tolerates. The allowable time for communication quality degradation is used in the decision-making process in step 1105 of Figure 11, and is shown in time (e.g., seconds) for each application. Exceeding this time will cause problems with processing in that application. In the downlink application list 1301 in Figure 13, the allowable time for communication quality degradation is 1 second for "APP-DOWN-1" and 2 seconds for "APP-DOWN-2".

[0126] The uplink application list 1302 has the same configuration as the downlink application list 1301. Figure 13 shows that the allowable time for communication quality degradation in the downlink application list 1301 is 1 second for "APP-UP-1" and 2 seconds for "APP-UP-2". Since there may be applications that only perform downlink communication or only perform uplink communication for applications that communicate between communication platforms 102 and 115, application lists are maintained separately for each communication direction, as shown in Figure 13.

[0127] <List of communication channels used by application> Figure 14 shows an example of the configuration of the application-specific channel usage list in the communication system of the present invention. Figure 14 shows an example of the configuration of the application-specific channel usage list in Example 1, Example 3, and Example 4. The application-specific channel usage list is a list that shows the relationship between information on the application, the travel section and travel time of the mobile body, and the channel used by the application. The upper part of Figure 14 shows the application-specific channel usage list 1401 for downlink communication, and the lower part shows the application-specific channel usage list 1402 for uplink communication. The application-specific channel usage list 1401 for downlink communication and the application-specific channel usage list 1402 for uplink communication are stored in the communication control setting DB 204 in the communication control device 103.

[0128] The application-specific channel usage list 1401 for downlink communication consists of an application identifier, information on the time period to which communication control settings are applied, information on the travel section, and information on the communication channel. In Figure 14, the application identifier is shown as the application ID. In Figure 14, the information on the time period to which communication control settings are applied is shown as the time period. The travel section information is information on the travel section of the mobile body to which the communication control settings are applied, and in Figure 14, the range of the travel section is shown. The communication channel information shows the information on the communication channel used for communication between communication platforms 102 and 115 during the time period and travel section to which the application specified by the application ID applies. In Figure 14, the communication channel information is shown as the destination communication channel ID. In Figure 14, one communication channel (destination communication channel ID) is selected for each application ID, time period, and travel section. This is an example of a communication channel determined in step 1107, etc., in Figure 11.

[0129] The application-specific channel usage list 1402 for uplink communication has the same configuration as the application-specific channel usage list 1401 for downlink communication. Among applications communicating between communication platforms 102 and 115, there may be applications that only perform downlink communication or applications that only perform uplink communication. Therefore, as shown in Figure 14, a channel usage list is maintained separately for each communication direction.

[0130] As described above, in the embodiments including Example 1, in a communication system that communicates with a mobile object, the communication quality estimation device 104 maintains a model that evaluates the impact of handover on the communication quality of an application at each handover point. The communication control device 103 then obtains communication quality estimation results from the communication quality estimation device 104 based on information about the application, the mobile object's travel section, and the time of day. The communication quality estimation results take into account the impact that the communication quality of the application is affected by handover at each handover point. Based on the communication quality estimation results, the communication control device 103 reflects a communication path that can avoid or suppress the impact of handover. The communication control device 103 generates communication control settings for communication platforms 102 and 115 using this communication path and reflects them in the operation of communication platforms 102 and 115. This makes it possible to perform communication control that avoids or suppresses the deterioration of the communication quality of the application caused by handover.

[0131] <Communication control method selection process in Example 2> Figure 15 is a flowchart showing an example of the communication control method selection process in the communication system of Example 2. The communication control method selection process in Example 2 differs from that of Example 1. This document mainly describes the differences between Example 2 and Example 1, and for points not specifically mentioned, the same configuration as in Example 1 can be applied.

[0132] The communication control method selection process in Example 2 performs a communication quality estimation for each candidate communication channel, including the impact of handover-induced degradation of the application's communication quality. This is done based on information about the application using the communication system, the travel section of the mobile vehicle, and the travel time. The system then determines the combination of communication channels to which the application will apply route redundancy control during the application, the travel section of the mobile vehicle, and the travel time. Here, the impact of handover-related degradation of the application's communication quality due to handover processing and post-handover reconnection processing is considered.

[0133] The operation based on the flowchart shown in Figure 15 is as follows. The processing here is performed by the communication control device 103.

[0134] First, in step 1501, the communication control method selection process is initiated.

[0135] Next, in step 1502, a list of candidate communication channels to be used for application communication is obtained from the communication channel DB202.

[0136] Next, in step 1503, a list of combinations of usable communication channel candidates is generated based on the information from the list of candidate communication channels obtained in step 1502. The list of combinations may include, for example, a list of combinations in which two usable communication channels are selected from three candidate communication channels, or a list of combinations in which all three usable communication channels are selected from three candidate communication channels.

[0137] Next, in step 1504, it is determined whether there are any unevaluated combinations of candidate communication channels generated in step 1503. The evaluation here assesses whether the application's communication quality requirements can be achieved by using the communication channels together. If there are unevaluated candidate combinations, the process proceeds to step 1505. Otherwise, the process proceeds to step 1510.

[0138] The combination of usable communication channels shown here is, for example, the combination of the first mobile carrier network 105 and the second mobile carrier network 110 in Figure 1. In this case, packet communication is sent from the communication platform 102 to both mobile carrier networks 105 and 110, and the packets that arrive first at the communication platform 115 are forwarded to the edge-side application terminal 116. This reduces the impact of handover. In addition, while increasing the number of communication channels reduces the impact of handover, it also increases communication costs, so it may be better to select combinations in order of the smallest number of communication channels.

[0139] In step 1505, the communication quality is estimated for each communication channel in the combination of unevaluated communication channels selected in step 1504. Specifically, the communication control setting generation unit 203 requests the communication quality estimation device 104 to estimate the communication quality, taking into account the travel section, time period, and application information of the mobile object to be evaluated, as well as the impact of handover for each communication channel constituting the candidate combination of communication channels. Subsequently, the communication control setting generation unit 203 obtains the communication quality estimation results for each communication channel constituting the combination of communication channels to be evaluated from the communication quality estimation device 104.

[0140] Next, in step 1506, the period during which the application's communication quality deteriorates due to handover in the communication channels constituting the combination is calculated from the communication quality estimation results obtained from the communication quality estimation device 104 in step 1505. The communication quality estimation results are the communication quality estimation results for each communication channel constituting the combination of communication channels under evaluation. Here, the period during which the application's communication quality deteriorates for the travel section and time period of the mobile object under evaluation is calculated. The period during which the communication quality deteriorates is the period during which the application's communication quality deteriorates simultaneously in each communication channel constituting the combination due to handover.

[0141] In step 1507, it is evaluated whether the period of application communication quality degradation due to handover occurring simultaneously on the shared communication channels, as calculated in step 1506, is less than or equal to the application's acceptable time for communication quality degradation. The application's acceptable time for communication quality degradation is obtained from the application DB201. Here, the evaluation based on the application's acceptable time for communication quality degradation can also be evaluated using information on communication quality degradation that the application tolerates, other than the acceptable time for communication quality degradation. For example, in Figure 15, instead of the acceptable time for communication quality degradation, evaluation may be performed using general communication quality evaluation indicators such as throughput, latency, and packet loss rate.

[0142] If the period during which the application's communication quality deteriorates due to handover simultaneously on the acquired shared communication channels is less than or equal to the application's acceptable time for communication quality deterioration, the process proceeds to step 1509. Otherwise, the process proceeds to step 1508.

[0143] In step 1508, information is obtained on the combinations of usable communication channel candidates that will be evaluated next. After that, the process returns to step 1504.

[0144] In step 1509, the combination of communication channels selected in step 1105 is determined as the combination of communication channels to be used for route redundancy control within the travel section under evaluation. The selected combination of communication channels is a combination of communication channels to be used in combination that satisfies the requirement for the allowable time of communication quality degradation of the application evaluated in step 1505, given the application under evaluation, the travel section of the mobile vehicle, and the time period. This combination of communication channels is the combination of communication channels used for route redundancy control between communication platforms 102 and 115. The process then proceeds to step 1511.

[0145] In step 1510, it is determined that there are no usable communication channel combinations, as none of the combinations in the list of communication channel combinations generated in step 1502 satisfy the application's requirement for acceptable communication quality degradation time. The process then proceeds to step 1511.

[0146] Step 1511 terminates the communication control method selection process.

[0147] Thus, in Embodiment 2, the communication control device 103, in the communication control setting generation unit 203, selects a combination of communication channels to be used in combination so that the application is not affected by the deterioration of communication quality due to handover in the travel section and time period of the mobile object under evaluation. This selection of a combination of communication channels is performed by requesting and obtaining a communication quality estimation result that takes into account the effects of handover from the communication quality estimation device 104 for each candidate combination of communication channels to be used in combination for application communication. This makes it possible to perform communication control that avoids or suppresses the deterioration of the application's communication quality caused by handover processing and reconnection processing after handover, while using multiple communication channels in combination.

[0148] <List of communication channels used by application in Example 2> Figure 16 shows an example of the configuration of the application-specific channel usage list in the communication system of Embodiment 2. The application-specific channel usage list in Embodiment 2 is a list that shows the relationship between information on the application, the travel section and time of travel of the mobile body, and the combination of channel to which the application applies route redundancy control. The upper part of Figure 16 shows the application-specific channel usage list 1601 for downlink communication, and the lower part shows the application-specific channel usage list 1602 for uplink communication. The application-specific channel usage list 1601 for downlink communication and the application-specific channel usage list 1602 for uplink communication are stored in the communication control setting DB 204 in the communication control device 103.

[0149] The application-specific channel usage list 1601 for downlink communication consists of an application identifier, information on the time period for which communication control settings are applied, information on the travel section, and information on the communication control settings. In Figure 16, the application identifier is shown as the application ID. In Figure 16, the information on the time period for which communication control settings are applied is shown as time period information. The travel section information is information on the travel section of the mobile body to which the communication control settings are applied, and in Figure 16, the range of the travel section is shown. The communication control setting information consists of information on the communication control settings used for communication between communication platforms 102 and 115 during the time period and travel section to which the application specified by the application ID applies. In Figure 16, the communication control setting information is shown as information on the destination channel. In Figure 16, combinations of communication channels are shown for each application ID, time period, and travel section. In Figure 16, as an example, combinations of two communication channels are shown. This is an example of a combination of communication channels determined in step 1509 of Figure 15.

[0150] The application-specific channel usage list 1602 for uplink communication has the same configuration as the application-specific channel usage list 1601 for downlink communication. Among applications communicating between communication platforms 102 and 115, there may be applications that only perform downlink communication or applications that only perform uplink communication. Therefore, as shown in Figure 16, a channel usage list is maintained separately for each communication direction.

[0151] As described above, according to Embodiment 2, the communication control device 103 generates a combination of communication channels that can be used in conjunction with the application's communication based on information about the application, the mobile vehicle's travel section, and the time of day. For each combination of communication channels to be used, the communication control device 103 obtains from the communication quality estimation device 104 the effect of handover on the application's communication quality at each handover point as a communication quality estimation result. Based on the communication quality estimation result, the communication control device 103 generates communication control settings for communication platforms 102 and 115 to use a combination of communication channels that can avoid or suppress the effects of handover by using multiple communication channels. Based on the generated communication control settings, the communication control device 103 uses route redundancy control to perform application communication using multiple communication channels on communication platforms 102 and 115. This enables communication control that avoids or suppresses the deterioration of the application's communication quality caused by handover.

[0152] <Communication system of Example 3> Figure 17 illustrates a method for avoiding or suppressing the impact of handover on application communication quality degradation in the communication system of Example 3. The communication system of Example 3 avoids or suppresses the impact of handover on application communication quality degradation by deploying multiple wireless terminals on a mobile device and using multiple wireless communication terminals in combination. Here, we consider the impact of handover processing and reconnection processing after handover on the application communication quality. Example 3 mainly describes the differences from Example 1, and for points not specifically mentioned, the same configuration as in Example 1 can be applied.

[0153] Figure 17 illustrates the concept using train 1750, which travels on a railway line, as an example of a mobile entity. The mobile entity could also be a car, aircraft, ship, or automated guided vehicle. The explanation assumes that train 1750 communicates with the ground using a wireless system, traveling from station A to station B. Multiple wireless terminals are mounted on train 1750, physically spaced apart by an offset amount. In the example in Figure 17, the first wireless terminal 1701 is located in the leading car of train 1750, and the second wireless terminal 1702 is located in the trailing car. Communication between train 1750 and the ground utilizes a communication path via both the first wireless terminals 1701 and the second wireless terminal 1702. At time t0, when train 1750 is stopped at station A, the base station to which the first radio terminal 1701 and the second radio terminal 1702 are connected is the first base station 1711.

[0154] When train 1750 is traveling from station A to station B, at time t1, the first wireless terminal 1701 installed in the leading car of train 1750 approaches the handover point between the first base station 1711 and the second base station 1712. The first wireless terminal 1701 performs a handover process to continue communication between the ground and the onboard application. Alternatively, if the handover process fails, it performs a reconnection process after the handover. In this case, if the last car of train 1750 has not yet approached the handover point, the second wireless terminal 1702 installed in the last car can continue communication because it maintains a connection with the first base station 1711 at time t1.

[0155] Subsequently, as train 1750 continues towards station B, at time t2, the last car of train 1750 approaches the handover point between the first base station 1711 and the second base station 1712. The second radio terminal 1702 performs the handover process and the reconnection process after the handover, similar to the first radio terminal 1701 at time t1. At this point, the first radio terminal 1701 has already completed the handover process and the reconnection process after the handover, and is connected to the second base station 1712. Therefore, communication with the ground can continue using the first radio terminal 1701.

[0156] In this way, multiple wireless terminals are placed on a mobile device at a distance from each other, and communication is performed using multiple communication paths through each wireless terminal through path redundancy control, etc. This makes it possible to stagger the timing at which handover processing occurs and the communication quality of the application is affected. As a result, it is possible to avoid or suppress the impact on the communication quality between the mobile device and the ground due to handover processing and reconnection processing after handover.

[0157] <Communication control method selection process in Example 3> Figure 18 is a flowchart showing an example of the communication control method selection process in the communication system of Embodiment 3. The communication control method selection process in Embodiment 3 involves placing multiple wireless terminals on a mobile device and using the multiple installed wireless terminals in combination to avoid or suppress the impact of handover-induced deterioration of application communication quality.

[0158] The operation based on the flowchart shown in Figure 18 is as follows. The processing here is performed by the communication control device 103.

[0159] First, in step 1801, the communication control method selection process is initiated.

[0160] Next, in step 1802, a list of candidate communication channels to be used for application communication is obtained from the communication channel DB202.

[0161] Next, in step 1803, based on the information from the candidate channel list obtained in step 1802, a list of wireless terminals on the mobile device that will use each candidate channel is obtained.

[0162] Next, in step 1804, based on the information from the list of wireless terminals on the mobile body obtained in step 1803, the mobile body's travel position and travel speed, and the offset amount of the wireless terminal's installation position are obtained for each wireless terminal on the mobile body.

[0163] Next, in step 1805, the communication quality of each wireless terminal's communication channel on the mobile device is estimated. Specifically, based on the list of wireless terminals on the mobile device obtained in step 1803, the communication control setting generation unit 203 requests the communication quality estimation device 104 to estimate the communication quality, taking into account the effects of handover for each communication channel configured by each wireless terminal. Subsequently, the communication control setting generation unit 203 obtains the communication quality estimation results from the communication quality estimation device 104.

[0164] Next, in step 1806, based on the communication quality estimation results for each wireless terminal obtained in step 1805, the period during which communication paths using multiple wireless terminals are simultaneously affected by the deterioration of communication quality due to handover at each travel position of the mobile object is calculated. In this case, the travel speed of the mobile object is also taken into consideration.

[0165] Next, in step 1807, it is evaluated whether the period affected by the degradation of communication quality due to handover, calculated in step 1806, is less than or equal to the application's acceptable time for communication quality degradation. The application's acceptable time for communication quality degradation is obtained from the application DB201. Here, the evaluation based on the application's acceptable time for communication quality degradation can also be evaluated using information on other communication quality degradation that the application tolerates. For example, in Figure 18, instead of the acceptable time for communication quality degradation, evaluation may be performed using general communication quality evaluation indicators such as throughput, latency, and packet loss rate.

[0166] If the period during which the communication path using multiple acquired wireless terminals is simultaneously affected by the degradation of communication quality due to handover is less than or equal to the application's allowable time for communication quality degradation, the process proceeds to step 1808. Otherwise, the process proceeds to step 1809.

[0167] In step 1808, the communication control setting generation unit 203 applies the setting of the shared communication path by the wireless terminals to the communication platforms 102 and 115 by setting the offset amount with the position of each wireless terminal on the mobile body obtained in step 1804. This avoids or suppresses the impact on the communication quality of the application during handover processing and reconnection processing after handover. The process then proceeds to step 1810.

[0168] In step 1809, the communication control setting generation unit 203 determines that setting the offset amount between the position of each wireless terminal on the mobile body and the position of the mobile body, as obtained in step 1804, does not allow for avoiding or suppressing the impact of handover on the communication quality of the application. The process then proceeds to step 1810.

[0169] Step 1810 ends the communication control method selection process.

[0170] As described above, in Example 3, multiple wireless terminals are placed at a distance from each other on the mobile body, as shown in Figure 17, and the communication path using these wireless terminals is used in combination. This makes it possible to perform communication control that avoids or suppresses the impact on the communication quality of the application caused by handover that occurs as the mobile body moves.

[0171] <List of communication quality evaluation models for Example 4> Figure 19 shows an example of the configuration of the communication quality evaluation model list in Example 4. Example 4 mainly describes the differences from Example 1, and for points not specifically mentioned, the same configuration as in Example 1 can be applied. The communication quality evaluation model list in Example 4 is a list showing the relationship between the handover type and a communication quality evaluation model that considers the impact of handover-induced degradation of application communication quality, which has been generated in advance through simulation evaluation or the like. The upper part of Figure 19 shows the communication quality evaluation model list 1901 for downlink communication, and the lower part shows the communication quality evaluation model list 1902 for uplink communication. The communication quality evaluation model list 1901 for downlink communication and the communication quality evaluation model list 1902 for uplink communication are stored in the communication quality evaluation model DB 302 in the communication quality estimation device 104.

[0172] List 1901 of the communication quality evaluation model for downlink communication consists of information on handover processing and information on communication quality characteristics affected by handover. Figure 19 shows the handover type, transition system, presence or absence of TAU (Tracking Area Update), and train speed as information on handover processing. The information on communication quality characteristics affected by handover refers to the communication quality characteristics affected by handover processing and post-handover reconnection processing, and Figure 19 shows the throughput degradation period model. The handover type indicates the type of base station crossed during the handover. The throughput degradation period model shows the probability distribution of communication interruption time (the period during which communication quality degradation occurs) for each time period (morning, noon, night). This probability distribution takes into account measurement results from the train being measured, such as the number of passengers and train speed. Therefore, by using a threshold that identifies periods above a predetermined probability, the period during which communication quality degradation occurs can be identified. Furthermore, since the throughput degradation period model may have different characteristics depending on the speed range of the train (mobile object), it may be divided into multiple predetermined speed ranges. Figure 19 shows the cases divided into those slower than 60 km / h and those above 60 km / h.

[0173] The communication quality evaluation model list 1902 for uplink communication has the same configuration as the communication quality evaluation model list 1901 for downlink communication. Generally, when a mobile device passes through a handover point, the impact of the handover process and the reconnection process after the handover on communication quality differs between downlink and uplink communication. Therefore, as shown in Figure 19, a communication quality evaluation model list is maintained for each communication direction.

[0174] Example 4 demonstrates a simulation that can be applied even when the moving object does not actually travel the same route. In this case, as shown in Figure 19, the type of handover is identified, and when conditions such as the presence or absence of a TAU, the travel environment, and the train's speed are met, it becomes possible to estimate the period during which communication quality degradation occurs from the throughput degradation period model. Once the period during which communication quality degradation occurs can be estimated, the configurations of Examples 1 to 3 can be applied.

[0175] As shown in Figure 19, information on the communication quality characteristics affected by each type of handover is stored as a communication quality evaluation model. These evaluation models may be generated from measured data or from simulation evaluations.

[0176] As described above, in Example 4, the communication quality estimation device 104 maintains information on the communication quality characteristics affected by each type of handover as a communication quality evaluation model. This makes it possible to construct a communication quality evaluation based on data previously measured or generated by simulation evaluations. In other words, it can be applied even when it is not possible to obtain real-time measurement data on the impact of handover on the communication quality of an application for each handover point within the section in which a mobile object is traveling.

[0177] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are included. For example, the embodiments described above are described in detail to make the present invention easier to understand, and are not necessarily limited to those having all the configurations described. Furthermore, it is possible to replace parts of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add configurations from other embodiments to the configuration of one embodiment. In addition, it is possible to add, delete, or replace parts of the configuration of each embodiment with other configurations.

[0178] For example, the above embodiment illustrates a communication system that uses two communication platforms 102 and 115, one on the ground side and the other on the mobile side, to perform communication control that avoids or suppresses the impact of handover on the communication quality of an application. However, it can be applied to various other communication platforms and communication devices. Among these, the present invention is particularly suitable for use cases that communicate with mobile objects, where the mobile object moves frequently and the communication quality of the application is easily affected by handover. For example, it can be applied to communication systems, communication platforms, and communication devices for control and monitoring applications of mobile objects (automobiles, trains, airplanes, etc.) on roads, railway lines, air routes, etc.

[0179] Furthermore, although the communication channels described in Figure 1 are shown as two mobile carrier networks, the system is not limited to these; two or more, or even three or more, or even four or more, communication channels may be applied.

[0180] Furthermore, although the communication control device 103 and the communication quality estimation device 104 are shown as separate communication systems in Figure 1, they may be configured as a single integrated device. In this case, the hardware configurations shown in Figures 4 and 5 may be used interchangeably.

[0181] Furthermore, the communication quality evaluation model may also include information on base station deployment density.

[0182] Furthermore, each of the configurations, functions, processing units, processing means, etc. described in the above embodiments may be implemented in hardware, for example, by designing them as integrated circuits, or they may be implemented in software by having a processor interpret and execute programs that realize each function.

[0183] Furthermore, information such as programs, tables, and files that implement each function can be stored in memory, hard disks, SSDs (Solid State Drives), or recording media such as IC cards, SD cards, DVDs, and Blu-ray discs.

[0184] Furthermore, in the above embodiment, the control lines and information lines shown are those deemed necessary for explanatory purposes. Therefore, not all control lines and information lines necessary for implementation are necessarily shown.

[0185] This specification also includes disclosures of the following aspects: (Aspect 1) A communication system comprising: a communication quality estimation device that estimates communication quality taking into account the effects of handover processing and reconnection processing after handover; and a communication control device that performs communication control to avoid or suppress the effects of deterioration of communication quality due to handover processing and reconnection processing after handover based on the communication quality estimated by the communication quality estimation device.

[0186] (Aspect 2) In the communication system described in Embodiment 1, The communication quality estimation device creates a communication quality evaluation model that estimates the communication quality affected by the handover process and the reconnection process after the handover. The aforementioned communication quality evaluation model is a communication system characterized by recording at least one of the following conditions related to handover: communication system information, base station information, location, speed, time of day, base station density, and handover type, together with communication quality information at the time of handover.

[0187] (Aspect 3) In the communication system described in Embodiment 1 or Embodiment 2, The communication quality estimation by the aforementioned communication quality estimation device is characterized by using data obtained by measuring the effects of communication quality degradation due to handover processing and reconnection processing after handover, when a mobile body equipped with a wireless terminal has previously passed through the same handover point.

[0188] (Aspect 4) In the communication system described in any one of Embodiments 1 to 3, The communication control device evaluates whether the communication quality, taking into account the effects of the handover process and the reconnection process after the handover estimated by the communication quality estimation device, satisfies the communication requirements of the application, and if it does not, performs communication control to avoid or suppress the effects of the handover process and the reconnection process after the handover.

[0189] (Appendix 5) In the communication system described in Embodiment 4, The aforementioned communication control device is characterized by performing communication control that avoids or suppresses the effects of communication quality degradation due to handover processing and reconnection processing after handover by switching to a communication path whose communication quality during handover satisfies the communication requirements of the application.

[0190] (Aspect 6) In the communication system described in Embodiment 4, The aforementioned communication control device is characterized by performing communication control that avoids or suppresses the effects of handover processing and reconnection processing after handover by selecting a combination of communication paths used in combination that ensures the communication quality satisfies the communication requirements of the application.

[0191] (Aspect 7) In the communication system described in Embodiment 4, The communication control device is a communication system characterized by arranging multiple wireless terminals that communicate with a mobile object at intervals, and performing communication control to avoid or suppress the effects of handover processing and reconnection processing after handover by using the multiple wireless terminals in combination.

[0192] (Pattern 8) A communication device comprising: a communication quality estimation unit that estimates communication quality taking into account the effects of handover processing and reconnection processing after handover; and a communication control unit that performs communication control to avoid or suppress the effects of deterioration of communication quality due to handover processing and reconnection processing after handover based on the communication quality estimated by the communication quality estimation unit.

[0193] (Aspect 9) A communication method characterized by including a communication quality estimation step of estimating communication quality taking into account the effects of handover processing and reconnection processing after handover, and a communication control step of performing communication control to avoid or suppress the effects of deterioration of communication quality due to handover processing and reconnection processing after handover based on the communication quality estimated in the communication quality estimation step.

[0194] (Aspect 10) In the communication method described in aspect 9, The aforementioned communication quality estimation step involves creating a communication quality evaluation model that estimates the communication quality affected by the handover process and the reconnection process after the handover. The aforementioned communication quality evaluation model is a communication method characterized by recording at least one of the following conditions related to handover: communication system information, base station information, location, speed, time of day, base station density, and handover type, together with communication quality information at the time of handover.

[0195] (Aspect 11) In the communication method described in Embodiment 9 or Embodiment 10, The communication quality estimation step is characterized by using data obtained by having a mobile device equipped with a wireless terminal pass through the same handover point in advance, and measuring the impact of the deterioration of communication quality due to the handover process and the reconnection process after the handover.

[0196] (Aspect 12) In the communication method described in any one of embodiments 9 to 11, The communication method is characterized in that the communication control step evaluates whether the communication quality, taking into account the effects of the handover process and the reconnection process after the handover estimated in the communication quality estimation step, satisfies the communication requirements of the application, and if it does not, performs communication control to avoid or suppress the effects of the handover process and the reconnection process after the handover.

[0197] (Aspect 13) In the communication method described in Embodiment 12, The communication method is characterized in that the communication control step involves switching to a communication path whose communication quality during handover satisfies the communication requirements of the application, thereby avoiding or suppressing the effects of handover processing and reconnection processing after handover on the deterioration of communication quality.

[0198] (Aspect 14) In the communication method described in Embodiment 12, The communication method is characterized in that the communication control step selects a combination of communication paths used in combination that satisfies the communication requirements of the application, thereby performing communication control to avoid or suppress the effects of handover processing and reconnection processing after handover on the deterioration of communication quality.

[0199] (Aspect 15) In the communication method described in Embodiment 12, The communication control step is characterized by arranging a plurality of wireless terminals that communicate with a mobile object at intervals, and performing communication control to avoid or suppress the effects of handover processing and reconnection processing after handover by using the plurality of wireless terminals in combination. [Explanation of symbols]

[0200] 101...Server-side application terminal, 102...Communication platform, 103...Communication control device, 104...Communication quality estimation device, 105...First mobile carrier network, 106...First core network, 107...First wireless access network, 108...First wireless base station, 109...First wireless terminal, 110...Second mobile carrier network, 111...Second core network, 112...Second wireless access network, 113...Second wireless base station, 114...Second wireless terminal, 115...Communication platform, 1 16...Edge-side application terminal, 201...Application DB, 202...Communication channel DB, 203...Communication control setting generation unit, 204...Communication control setting DB, 205...Communication control setting management unit, 206...Mobile device information DB, 301...Communication quality estimation unit, 302...Communication quality evaluation model DB, 303...Measurement information receiving unit, 304...Communication quality model generation unit, 401...Processor, 402...Memory, 403...Input interface, 404...Auxiliary storage device, 405...Communication interface, 406...Output interface, 407...Keyboard, 408...Mouse S, 409...Display device, 501...Processor, 502...Memory, 503...Input interface, 504...Auxiliary storage device, 505...Communication interface, 506...Output interface, 507...Keyboard, 508...Mouse, 509...Display device, 601...Station A, 602...Station B, 610...Train, 901...Communication quality evaluation model list for downlink communication, 902...Communication quality evaluation model list for uplink communication, 1201...Downlink communication channel list, 1202...Uplink communication channel list, 1301...Application list for downlink communication, 1 302…Uplink communication application list, 1401…Downlink communication application-specific channel usage list, 1402…Uplink communication application-specific channel usage list, 1601…Downlink communication application-specific channel usage list, 1602…Uplink communication application-specific channel usage list, 1701…First wireless terminal, 1702…Second wireless terminal, 1711…First base station, 1712…Second base station, 1750…Train, 1901…Downlink communication quality evaluation model list, 1902…Uplink communication quality evaluation model list

Claims

1. A communication system comprising: a communication quality estimation device that estimates communication quality taking into account the effects of handover processing and reconnection processing after handover; and a communication control device that performs communication control to avoid or suppress the effects of deterioration of communication quality due to handover processing and reconnection processing after handover based on the communication quality estimated by the communication quality estimation device.

2. In the communication system described in claim 1, The communication quality estimation device creates a communication quality evaluation model that estimates the communication quality affected by the handover process and the reconnection process after the handover. The aforementioned communication quality evaluation model is a communication system characterized by recording at least one of the following conditions related to handover: communication system information, base station information, location, speed, time of day, base station density, and handover type, together with communication quality information at the time of handover.

3. In the communication system described in claim 1, The communication quality estimation by the aforementioned communication quality estimation device is characterized by using data obtained by measuring the effects of communication quality degradation due to handover processing and reconnection processing after handover, when a mobile body equipped with a wireless terminal has previously passed through the same handover point.

4. In the communication system described in claim 1, The communication control device evaluates whether the communication quality, taking into account the effects of the handover process and the reconnection process after the handover estimated by the communication quality estimation device, satisfies the communication requirements of the application, and if it does not, performs communication control to avoid or suppress the effects of the handover process and the reconnection process after the handover.

5. In the communication system described in claim 4, The aforementioned communication control device is characterized by performing communication control that avoids or suppresses the effects of communication quality degradation due to handover processing and reconnection processing after handover by switching to a communication path whose communication quality during handover satisfies the communication requirements of the application.

6. In the communication system described in claim 4, The aforementioned communication control device is characterized by performing communication control that avoids or suppresses the effects of handover processing and reconnection processing after handover by selecting a combination of communication paths used in combination that ensures the communication quality satisfies the communication requirements of the application.

7. In the communication system described in claim 4, The communication control device is a communication system characterized by arranging multiple wireless terminals that communicate with a mobile object at intervals, and performing communication control to avoid or suppress the effects of handover processing and reconnection processing after handover by using the multiple wireless terminals in combination.

8. A communication device comprising: a communication quality estimation unit that estimates communication quality taking into account the effects of handover processing and reconnection processing after handover; and a communication control unit that performs communication control to avoid or suppress the effects of deterioration of communication quality due to handover processing and reconnection processing after handover based on the communication quality estimated by the communication quality estimation unit.

9. A communication method characterized by including a communication quality estimation step of estimating communication quality considering the effects of handover processing and reconnection processing after handover using a communication quality estimation device, and a communication control step of performing communication control based on the communication quality estimated in the communication quality estimation step to avoid or suppress the effects of deterioration of communication quality due to handover processing and reconnection processing after handover using a communication control device.

10. In the communication method described in claim 9, The aforementioned communication quality estimation step involves creating a communication quality evaluation model that estimates the communication quality affected by the handover process and the reconnection process after the handover. The aforementioned communication quality evaluation model is characterized by recording at least one of the following conditions related to handover—communication system information, base station information, location, speed, time of day, base station density, and handover type—along with communication quality information at the time of handover.

11. In the communication method described in claim 9, The communication quality estimation step is characterized by using data obtained by having a mobile device equipped with a wireless terminal pass through the same handover point in advance, and measuring the impact of the deterioration of communication quality due to the handover process and the reconnection process after the handover.

12. In the communication method described in claim 9, The communication method is characterized in that the communication control step evaluates whether the communication quality, taking into account the effects of the handover process and the reconnection process after the handover estimated in the communication quality estimation step, satisfies the communication requirements of the application, and if it does not, performs communication control to avoid or suppress the effects of the handover process and the reconnection process after the handover.

13. In the communication method described in claim 12, The communication method is characterized in that the communication control step involves switching to a communication path whose communication quality during handover satisfies the communication requirements of the application, thereby avoiding or suppressing the effects of handover processing and reconnection processing after handover on the deterioration of communication quality.

14. In the communication method described in claim 12, The communication method is characterized in that the communication control step selects a combination of communication paths used in combination that satisfies the communication requirements of the application, thereby performing communication control to avoid or suppress the effects of handover processing and reconnection processing after handover on the deterioration of communication quality.

15. In the communication method described in claim 12, The communication control step is characterized by arranging a plurality of wireless terminals that communicate with a mobile object at intervals, and performing communication control to avoid or suppress the effects of handover processing and reconnection processing after handover by using the plurality of wireless terminals in combination.

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