Communication performance management server, communication performance management method, and computer program

Abstract

This communication record management server comprises: a communication record information reception unit for receiving communication record information that includes at least location information, date and time information, and communication quality metrics information related to at least communication quality of wireless communication at a location identified by the location information and at a date and time identified by the date and time information; a communication record information storage unit for accumulating communication record information received by the communication record information reception unit; and a communication record transmission unit for generating, in response to receiving from an external device a transmission request for transmission of communication record information for which a regional range is specified, communication record-related information on the basis of the communication record information accumulated in the communication record information storage unit, and transmitting the generated communication record-related information to the external device, the communication record-related information including location information corresponding to a location within the regional range specified by the transmission request and communication quality information obtained from the communication quality metrics information.

Description

Technical Field

[0001] This disclosure relates to a communication performance management server, a communication performance management method, and a computer program. This application claims priority based on Japanese Application No. 2022-166644 filed on October 18, 2022, and incorporates herein by reference all the descriptions set forth in the said Japanese application.

Background Art

[0002] In-vehicle devices having functions of receiving various services from an external server or transmitting information acquired by in-vehicle sensors to an external server via wireless communication are increasing. Vehicles equipped with such in-vehicle devices are called connected cars.

[0003] When a connected car uses a service that assumes wireless communication, communication quality becomes an issue. If the communication quality deteriorates or the vehicle goes out of the communication range, the use of the service cannot be continued.

[0004] One proposal for solving such problems is disclosed in Patent Document 1 below. The technology disclosed in Patent Document 1 aims to visually notify the communication environment. The technology disclosed in Patent Document 1 acquires an electric field strength map indicating a predetermined electric field strength, and superimposes and displays the electric field strength map on a graphic indicating the traveling position of a vehicle based on road map data and the vehicle position.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

[0006] A communication performance management server relating to one aspect of this disclosure includes: a communication performance information receiving unit for receiving communication performance information which includes at least location information, date and time information, and communication quality metrics information relating at least to the communication quality of wireless communication at a location specified by the location information and at a date and time specified by the date and time information; a communication performance information storage unit for storing communication performance information received by the communication performance information receiving unit; and a communication performance transmission unit which, in response to receiving a transmission request for communication performance information with a specified geographical range from an external device, generates communication performance information which includes location information corresponding to the geographical range specified by the transmission request and communication quality information obtained from the communication quality metrics information, based on the communication performance information stored in the communication performance information storage unit, and transmits it to the external device.

[0007] The above and other purposes, features, aspects and advantages of this disclosure will become apparent from the following detailed description of this disclosure, which will be understood in conjunction with the attached drawings. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 shows the route suggestion screen in the in-vehicle device according to the first embodiment. [Figure 2] Figure 2 is a block diagram showing the overall configuration of the vehicle support system according to the first embodiment. [Figure 3] Figure 3 is a block diagram showing the configuration of the in-vehicle device according to the first embodiment. [Figure 4] Figure 4 is a block diagram showing the configuration of the communication performance management server according to the first embodiment. [Figure 5] Figure 5 shows the record structure of the communication performance information DB (Database) according to the first embodiment. [Figure 6] Figure 6 is a flowchart showing the control structure of a computer program that implements the communication record recording unit according to the first embodiment. [Figure 7] Figure 7 is a flowchart showing the control structure of the computer program that realizes the operation unit according to the first embodiment. [Figure 8] Figure 8 is a flowchart showing the control structure of a computer program that implements the route calculation unit according to the first embodiment. [Figure 9] Figure 9 is a flowchart showing the control structure of a computer program that implements the grid drawing unit according to the first embodiment. [Figure 10] Figure 10 is a block diagram showing the configuration of the vehicle support system according to the second embodiment. [Figure 11] Figure 11 is a block diagram showing the configuration of the in-vehicle device according to the second embodiment. [Figure 12] Figure 12 is a block diagram showing the configuration of the communication performance management server according to the second embodiment. [Figure 13] Figure 13 is a block diagram showing the configuration of the vehicle support system according to the third embodiment. [Figure 14] Figure 14 is a block diagram showing the configuration of the in-vehicle device according to the third embodiment. [Figure 15] Figure 15 is a flowchart showing the control structure of a computer program that implements the communication performance comparison unit according to the third embodiment. [Figure 16] Figure 16 is a block diagram showing the configuration of the driver assistance system according to the fourth embodiment. [Figure 17] Figure 17 is a block diagram showing the configuration of the in-vehicle device according to the fourth embodiment. [Figure 18] Figure 18 is a block diagram showing the configuration of the communication performance management server according to the fourth embodiment. [Figure 19] Figure 19 shows the record structure of the communication performance statistics database according to the fourth embodiment. [Figure 20] Figure 20 is a flowchart showing the control structure of a computer program that implements the communication statistics calculation unit in the communication performance management server according to the fourth embodiment. [Figure 21] Figure 21 is a flowchart showing the control structure of the computer program that implements the communication record transmission unit in the communication record management server according to the fourth embodiment. [Figure 22]FIG. 22 is a block diagram showing a functional configuration of a communication performance management server according to a modification of the fourth embodiment. [Figure 23] FIG. 23 is a diagram showing a display in a vehicle support system according to the fifth embodiment. [Figure 24] FIG. 24 is a flowchart showing a control structure of a computer program for creating a display in the vehicle support system according to the fifth embodiment. [Figure 25] FIG. 25 is a flowchart showing a control structure of a computer program for realizing a display of a travel route. [Figure 26] FIG. 26 is a block diagram showing a configuration of steps for realizing an in-vehicle device according to each embodiment of this disclosure. [Figure 27] FIG. 27 is a diagram showing an appearance of a computer system for realizing each driving support server according to this disclosure. [Figure 28] FIG. 28 is a hardware configuration diagram of the computer system shown in FIG. 27.

Mode for Carrying Out the Invention

[0009] [Problems to be Solved by this Disclosure] For a connected car to receive sufficient services, it is not only the electric field strength that is important. Since the number of in-vehicle sensors is large and the data thereof is increasing, the communication speed when the connected car transmits sensor data to an external server or downloads data for driving support or the like from the external server is also important. Further, latency is also important in addition to these when communicating data related to vehicle safety.

[0010] In the technology disclosed in Patent Document 1, an electric field strength map is superimposed on a map. It is clear that communication speed decreases at locations with low electric field strength. However, high electric field strength does not necessarily mean that communication speed will increase. Depending on the situation, communication speed may decrease or latency may increase even with high electric field strength. Communication speed may also deteriorate suddenly even with only slight changes in the environment. The vehicle's position and surrounding conditions change moment by moment. Therefore, even if an electric field strength map is obtained, it is difficult to predict how communication speed, latency, etc. will actually change, and it is not guaranteed that sufficient communication quality for using the service will be obtained while the connected car is in motion. In other words, the technology disclosed in Patent Document 1 is not considered sufficient for application to connected cars.

[0011] Therefore, this disclosure aims to provide a communication performance management server, a communication performance management method, and a computer program that provide information that facilitates the determination of a travel route that takes communication quality into consideration.

[0012] [Effects of this disclosure] As described above, this disclosure provides a communication performance management server, a communication performance management method, and a computer program that provide information that facilitates the determination of travel routes while considering communication quality.

[0013] [Description of Embodiments in this Disclosure] In the following descriptions and drawings, identical parts are given the same reference number. Therefore, detailed descriptions of them will not be repeated.

[0014] The main embodiments shown in this disclosure are listed below. Note that one or more of the following embodiments may be combined in any way.

[0015] (1) The communication performance management server relating to the first aspect of this disclosure includes a communication performance information receiving unit for receiving communication performance information which includes at least location information, date and time information, and communication quality metrics information relating at least to the communication quality of wireless communication at the location specified by the location information and at the date and time specified by the date and time information; a communication performance information storage unit for storing communication performance information received by the communication performance information receiving unit; and a communication performance transmission unit which, in response to receiving a transmission request for communication performance information with a specified geographical range from an external device, generates information relating to communication performance which includes location information corresponding to the geographical range specified by the transmission request and communication quality information obtained from the communication quality metrics information, based on the communication performance information stored in the communication performance information storage unit, and transmits it to the external device.

[0016] The communication performance information storage unit of this communication performance management server stores communication quality metrics information from actual communications by multiple devices, along with location information and date / time information. The communication performance transmission unit generates information about communication performance, including communication quality information, and transmits it to external devices upon request. External devices can use the communication quality information based on the actual communication performance of other devices to estimate and utilize the communication quality at a specific location. As a result, external devices can easily determine a travel route that takes communication quality into consideration.

[0017] (2) In (1) above, the communication record transmission unit may include a recent communication record transmission unit that reads communication record information from the communication record information storage unit, including location information corresponding to the geographical range specified by the transmission request, date and time information within the most recent predetermined time, and communication quality metric information, and transmits it to an external device.

[0018] The recent communication record transmission unit transmits communication record information for the most recent specified time period within the area specified by the transmission request to an external device. As a result, the external device can easily determine the travel route while taking into account the current high-precision communication quality.

[0019] (3) In (1) or (2) above, each piece of communication performance information may further include communication environment information relating to the communication environment when wireless communication relating to the communication performance information was performed, and a transmission request may further include information relating to the communication environment of an external device, and the communication performance transmission unit may include a device-specific communication performance transmission unit that, in response to receiving a transmission request, reads communication performance information from the communication performance information storage unit, which includes location information corresponding to the geographical range specified by the transmission request, communication environment information consistent with the communication environment information included in the transmission request, and communication quality metrics information, and transmits it to the external device.

[0020] By including information about the external device's communication environment in its transmission request, the external device can obtain regional and date-specific communication performance information related to that communication environment. As a result, the external device can easily determine a travel route that takes into account the communication quality of the wireless communication equipment being used.

[0021] (4) In (3) above, the communication environment information may include communication line information, communication carrier information, or a combination thereof.

[0022] By including information about the communication line or carrier used by the external device in its transmission request, the external device can obtain regional and time-specific communication performance information related to that communication line or carrier. As a result, the external device can easily determine a travel route that takes into account the highly reliable communication quality of the wireless communication equipment it uses.

[0023] (5) In (1) above, the communication performance management server may further include a communication statistics calculation unit that performs statistical processing on communication performance information stored in the communication performance information storage unit, based on at least a location identified by location information, to calculate communication performance statistics information, and a communication performance statistics information storage unit that stores the communication performance statistics information calculated by the communication statistics calculation unit in association with location information, and the communication performance transmission unit may also include a communication performance statistics information transmission unit that, in response to receiving a request from an external device to transmit communication performance information with a specified geographical range, transmits to the external device the location information corresponding to the geographical range specified by the transmission request and the communication performance statistics information at the location identified by location information, from among the communication performance statistics information stored in the communication performance statistics information storage unit.

[0024] By including communication device information about its own wireless communication device in the transmission request, the external device can obtain regional and date-specific communication history information regarding communications by other devices that possess the same wireless communication device. As a result, the external device can easily determine the travel route while taking into account the communication quality of the wireless communication device being used.

[0025] (6) In the above (5), the communication statistics calculation unit may include a period-specific communication statistics calculation unit that performs statistical processing on communication quality metrics information based on at least a location specified by location information and a period specified by date and time information with respect to the communication performance information stored in the communication performance information storage unit to calculate period-specific communication performance statistics.

[0026] By including communication device information about its own wireless communication device in the transmission request, the external device can obtain regional and date-specific communication performance information from the external device using that wireless communication device. As a result, the external device can easily determine a travel route that takes into account the communication quality of the wireless communication device it is using.

[0027] (7) In (6) above, each piece of communication performance information may further include information about the communication environment when wireless communication relating to the communication performance information was performed, and a transmission request may include information about the communication environment of an external device, and the communication performance transmission unit may selectively perform the first process and the second process depending on whether the received transmission request includes information about the communication environment, and the first process is to retrieve from the communication performance statistics information storage unit a location information corresponding to the geographical range specified by the transmission request and information about the communication environment included in the transmission request that matches truth achievements statistics The information was read, and the retrieved communications Achievements control financial affairs The second process may involve calculating communication quality metrics information based on the report and transmitting it to an external device, or the second process may involve reading communication performance information corresponding to location information within the geographical range specified by the transmission request from the communication performance information storage unit and transmitting it to an external device.

[0028] This prevents an increase in the statistical processing load while transmitting to the in-vehicle device. communication This can improve the accuracy of quality metrics information.

[0029] (8) A communication record management method relating to the second aspect of this disclosure includes the steps of: a computer receiving communication record information which includes at least location information, date and time information, and communication quality metrics information relating at least to the communication quality of a wireless communication at a location specified by the location information and at a date and time specified by the date and time information; a computer storing the communication record information received in the step of receiving the communication record information in a storage device; and a computer, in response to receiving a request from an external device to transmit communication record information with a specified geographical range, generating communication record information which includes location information corresponding to the geographical range specified by the transmission request and communication quality information obtained from the communication quality metrics information, based on the communication record information stored in the storage device, and transmitting it to the external device.

[0030] According to this communication record management method, a computer stores communication records from actual communications between multiple devices, along with location and date / time information. Furthermore, the computer generates and transmits information about communication records, including communication quality information, to external devices upon request. External devices can then use this communication quality information, based on actual communication records from other devices, to estimate and utilize communication quality at specific locations. As a result, external devices can easily determine travel routes that take communication quality into consideration.

[0031] (9) A computer program relating to the third aspect of this disclosure causes the computer to perform the steps of: receiving communication performance information which includes at least location information, date and time information, and communication quality metrics information relating at least to the communication quality of a wireless communication at a location specified by the location information and at a date and time specified by the date and time information; storing the communication performance information received in the step of receiving the communication performance information in a storage device; and in response to receiving a request from an external device to transmit communication performance information with a specified geographical range, generating information relating to communication performance which includes location information corresponding to the geographical range specified by the transmission request and communication quality information obtained from the communication quality metrics information, based on the communication performance information stored in the storage device, and transmitting it to the external device.

[0032] When a computer runs this computer program, it stores communication records from actual communications between multiple devices, along with location and date / time information. Furthermore, upon request from an external device, the computer generates and transmits information about the communication records, including communication quality information. The external device can then use this communication quality information, based on the actual communication records of other devices, to estimate and utilize the communication quality at a specific location. As a result, the external device can easily determine a travel route that takes communication quality into consideration.

[0033] [Details of the embodiments of this disclosure] Specific examples of route suggestion screens according to the embodiments of this disclosure will be described below with reference to the drawings. However, this disclosure is not limited to these examples and is intended to include all changes within the meaning and scope of the claims, as indicated by the claims.

[0034] 1. First Embodiment A.Configuration A1) Route suggestion screen 50 Referring to Figure 1, the route suggestion screen 50 in the vehicle support system according to the first embodiment is a screen displayed on a touch panel display device of the in-vehicle device. The route suggestion screen 50 is for proposing to the user a first route 66 and a second route 68 from the vehicle's current location 62 to the destination 64, calculated under different constraints regarding communication quality along the route. The route suggestion screen 50 as a whole is rectangular. This rectangular area is divided into rectangular grids of the same size. In this embodiment, each grid is color-coded based on the communication quality actually measured by the vehicle when the vehicle is present within that grid, and is displayed superimposed on the map along with the first route 66 and the second route 68. Note that the map is not shown in Figure 1 for the sake of simplicity.

[0035] In Figure 1, grids without hatching indicate relatively good communication quality, sufficient for receiving the services intended for use in vehicle 60. Grids with hatching indicate worse communication quality, insufficient for receiving the services intended for use in vehicle 60. In this example, hatched areas are shown in red, while unhatched areas are shown transparently.

[0036] Figure 1 classifies the grid into two types to facilitate understanding of the communication quality indicator. However, this disclosure is not limited to such embodiments. Communication quality may be divided into three or more stages, each with a separate indicator. Typically, for example, a grid with poor communication quality is indicated by a red hue and the lowest brightness. As communication quality improves, the brightness of the grid is increased, and once a certain quality level is reached, it is indicated by colorless (transparent) or a color other than red (e.g., blue). Of course, there are many other ways to indicate the grid. The saturation may be changed without changing the brightness. Alternatively, both the hue and either the brightness or the saturation may be changed.

[0037] For example, typically, brightness should be changed with a positive correlation to the communication quality value. In the case of saturation, conversely, it can be changed with a negative correlation to the communication quality value. In short, the display pattern of each grid should change as a monotonic function of the communication quality in that grid. In the case of hue, a monotonic function should be used that correlates the gradual change from blue through green to red with the superiority or inferiority of the communication quality.

[0038] In Figure 1, a first route 66 and a second route 68 are also shown as examples. The first route 66 is calculated as the route that allows the vehicle 60 to reach the destination 64 from the current location 62 in the shortest time, without imposing any constraints on communication quality. Similarly, the second route 68 is also a route that allows the vehicle 60 to reach the destination 64 from the current location 62, but with a constraint on communication quality, it is calculated as a route that provides the communication quality necessary for the vehicle 60 to use a specific service.

[0039] The constraints on communication quality are not limited to those listed here; they can be set in various ways by the user of each vehicle (60).

[0040] A2) Vehicle support system 100 Referring to Figure 2, the vehicle support system 100 according to the first embodiment of this disclosure includes a plurality of in-vehicle devices 102, 104, and 106, each mounted on a separate vehicle, a server 108 for providing some kind of service to these in-vehicle devices using communication, or conversely, receiving sensor data from the in-vehicle devices to analyze traffic conditions, and a communication performance management server 110 for managing and distributing information on the actual communication quality in each grid in the area shown in Figure 1, based on communication with the plurality of in-vehicle devices such as the in-vehicle device 102.

[0041] Onboard devices such as the onboard device 102 are mounted in a vehicle. Therefore, as will be described later, they all have a wireless communication unit. A mobile phone network can be used as the medium for wireless communication. In some locations, the use of Wi-Fi communication is also envisioned. In any case, the onboard device 102 can communicate with the server 108 and the communication performance management server 110 via wireless communication between the onboard device and the base station, and via wired network communication between the base station and the server 108 and the communication performance management server 110.

[0042] A3) In-vehicle device 102 Referring to Figure 3, the in-vehicle device 102 includes a communication unit 150 for communicating with external devices such as a server 108 via a wireless communication device (not shown), a communication history recording unit 154 connected to the communication unit 150, a CAN (Controller Area Network) 152 connected to the sensor 112, a GNSS (Global Navigation Satellite System) receiver 114, and the communication history recording unit 154, and a communication history information DB 156 connected to the communication history recording unit 154. The communication unit 150 further receives data for services provided by the server 108 and transmits it via the CAN 152 to a service execution unit such as an ECU (Electronic Control Unit) (not shown). In this embodiment, CAN is used to acquire GNSS information and sensor information. However, this disclosure is not limited to such embodiments. For example, CAN FD (CAN with Fl exible Data rate), CAN XL,Most(Media Oriented Sy s You may also use technologies such as tems Transport, FlexRay, or automotive Ethernet ("Ethernet" is a registered trademark).

[0043] The communication record unit 154 periodically measures the communication quality when the communication unit 150 is communicating and records the communication quality, including the actual bitrate (communication speed). Even when the communication unit 150 is not communicating, radio wave strength information can be acquired and this information is also recorded.

[0044] The communication record unit 154 receives sensor data from the GNSS receiver 114 and other various sensors 112 mounted on the vehicle via CAN 152, and records a record of communication history in the communication history information DB 156, combining the vehicle status, location information, etc., obtained from this information.

[0045] The in-vehicle device 102 further includes a communication record transmission unit 158 ​​connected to a communication record recording unit 154, a communication record acquisition unit 160 connected to a communication record information DB 156, an operation unit 162 connected to a touch panel display device 116, a route calculation unit 164 connected to the communication record information DB 156, the operation unit 162, and the communication record acquisition unit 160, and a grid drawing unit 166.

[0046] The communication record transmission unit 158 ​​transmits the communication record information of the communication unit 150, recorded by the communication record recording unit 154, to the communication record management server 110 according to a predetermined transmission schedule. The communication record acquisition unit 160 acquires communication record information of other vehicles from the communication record management server 110 by sending a transmission request for communication record information to the communication record management server 110 when necessary, and updates (adds) the communication record information DB 156. The transmission request at this time includes information that identifies the target area, and may also include necessary date and time information or communication environment information. The communication environment here includes the communication line or communication carrier used for communication, or a combination thereof. The driving unit 162 is a device for performing autonomous driving or remote driving in addition to the functions of a typical in-vehicle navigation system, and receives input of information for route suggestion (information related to the destination of the driving route, etc.) through interaction with the user using a touch panel display device 116. The communication record acquisition unit 160 may also be configured to receive communication record information from the communication record management server 110 according to a predetermined schedule.

[0047] In this case, the driver unit 162 may allow the user to input constraints when generating the travel route. Constraints include, for example, the number of travel routes to be generated, information identifying the services to be used on the travel route, and conditions that the travel route must satisfy. In the following embodiment, it is assumed that the user has specified that three travel routes be generated. These three travel routes are, for example, the first shortest route to the third shortest route shown below. The first shortest route is the shortest route connecting the current location and the destination, regardless of the communication speed. The second shortest route is the shortest route among the travel routes for which a communication speed sufficient to use the service is expected throughout. The third shortest route is a travel route for which, although the service may not be available at a sufficient bitrate in some parts, it is expected that a service that can substitute for that service, or the same service as that service, will be available with the necessary bitrate if the communication speed is more than half of the specified bitrate.

[0048] The route calculation unit 164 requests the communication performance acquisition unit 160 to acquire information such as communication performance, necessary location, and time from the communication performance information DB 156, based on the user input received by the driving unit 162 and the communication conditions required to use the service. Based on the communication performance information acquired from the communication performance information DB 156 by the communication performance acquisition unit 160, destination information, and necessary communication conditions, the route calculation unit 164 calculates multiple travel routes under multiple types of constraints and displays them on the touch panel display device 116 via the driving unit 162. In this embodiment, the grid drawing unit 166 displays information indicating the communication performance in each part of the displayed area, superimposed on the travel route candidates and map displayed on the touch panel display device 116. Note that the communication performance information is information that combines the communication performance (communication speed or signal strength) with information indicating the state of the vehicle (vehicle speed or direction of travel, etc.) when the communication performance was acquired.

[0049] More specifically, the grid drawing unit 166 divides the displayed area into grids and overlays the color, brightness, or saturation of each grid, adjusted as a function of an index value representing past communication performance (communication quality) in each grid, onto the route candidates and map. Past communication performance is obtained from information stored in the communication performance information DB 156.

[0050] A4) Communication performance management server 110 Referring to Figure 4, the communication record management server 110 includes a communication record acquisition unit 200, a communication record information storage unit 202, and a communication record transmission unit 204.

[0051] The communication record acquisition unit 200 acquires communication record information collected by multiple in-vehicle devices at various locations and times. The communication record information storage unit 202 stores the communication record information received by the communication record acquisition unit 200. The communication record transmission unit 204 transmits the communication record information stored in the communication record information storage unit 202 to the in-vehicle device (for example, in-vehicle devices 102, 104, or 106 shown in Figure 2) of a subscriber to the communication record management service provided by the communication record management server 110 in response to a transmission request from that device. Note that the transmission of communication record information to the communication record acquisition unit 200 is not limited to in-vehicle devices. Any device with communication capabilities, such as a mobile phone, can be used. A mobile device is preferable, but a device that is not mobile but has communication capabilities, such as a roadside device, can also be used. In addition, the communication record transmission unit 204 may transmit communication record information to each in-vehicle device according to a predetermined schedule, rather than just responding to transmission requests from in-vehicle devices.

[0052] A5) Configuration of Communication Performance Information DB156 Figure 5 shows an example of the column structure of the Communication Record Information DB156 table. Referring to Figure 5, the columns of the Communication Record Information DB156 include Communication Record ID and Vehicle ID. The Communication Record ID is an identifier that identifies the record of the communication record. The Vehicle ID is an identifier that identifies the vehicle equipped with the in-vehicle device that recorded that communication record.

[0053] Other columns include, for example, measurement interval, modem, GNSS, date and time, latitude, longitude, grid ID, geometry value, communication speed, (vehicle) speed, (vehicle) heading, route ID, (vehicle) direction of travel, (vehicle) acceleration / deceleration, (vehicle) steering angle, accelerator operation, brake operation, communication line, carrier, band number, (cell phone) cell ID, SINR, RSSI, RSRP, and RSRQ.

[0054] To explain the main points of these: The measurement interval indicates the measurement interval for communication speed. The unit of the measurement interval is seconds. The date and time indicates the date and time when the in-vehicle device acquired the communication record. The latitude and longitude indicate the location where the vehicle was located at the time of communication, respectively. The grid ID is a value obtained by converting the latitude and longitude into a string using a conversion method called geohash. Geohash is converted into a string by applying a predetermined conversion table to the latitude and longitude. Each string identifies a certain rectangular area on the ground. The longer the string length, the smaller the rectangular area. If the first predetermined number of characters of two strings match, the two rectangular areas identified by those two strings are within the rectangular area identified by the matching string. If the string lengths used as geohash are the same, the size (area) of the rectangular areas identified by them is the same. Therefore, by setting the string length used as geohash to a fixed length and making the first few characters common, a map (or corresponding area) can be divided into multiple adjacent rectangular areas. Here, such rectangular regions are called grids, and their identifiers (latitude and longitude converted to geohash) are called grid IDs.

[0055] The communication speed, as indicated by the date and time column value, represents the measured communication speed for the actual communication that took place, provided that communication was possible at that time. If communication was impossible due to reasons such as being out of range, "-1" is recorded as the communication speed in this embodiment.

[0056] SINR, RSSI, RSRP, and RSRQ refer to the signal-to-interference noise ratio, received signal strength, received power of the reference signal, and received quality of the reference signal, respectively, and correspond to the radio wave strength information described above.

[0057] Thus, the communication performance information DB156 stores information indicating communication quality, including the communication speed measured during actual communication, along with the vehicle's status at the time (such as the vehicle's speed and direction of travel, as shown in Figure 5) and the date and time. This process updates the communication performance information DB156. The values ​​such as communication speed, SINR, RSSI, RSRP, and RSRQ shown in Figure 5, as well as their statistical values, are considered indicators of communication quality. Therefore, in this specification, these values ​​are referred to as "communication quality metrics," and the information showing these values ​​is referred to as "communication quality metrics information."

[0058] A6) Program control structure A6-1) Communication Record Section 154 Each functional part of the in-vehicle device 102 shown in Figure 3 is realized by a computer and a program executed by the computer.

[0059] Figure 6 shows the control structure of the program that implements the communication record recording unit 154 shown in Figure 3. Referring to Figure 6, this program includes step 250 which executes step 252 according to a predetermined schedule (a fixed period in this embodiment).

[0060] Step 252 includes step 260, which performs communication processing using the communication unit 150 or performs signal strength measurement processing; step 262, which acquires information indicating the status of the vehicle via CAN 152; and step 264, which combines the information acquired in steps 260 and 262 and records it in the communication performance information DB 156.

[0061] This program further includes step 266, which branches the control flow depending on whether or not there is a communication performance management server that is linked with the in-vehicle device 102, and step 268, which, if the determination in step 266 is positive, sends communication performance information to the linked communication performance management server and terminates the execution of step 252. If the determination in step 266 is negative, the execution of step 252 is terminated.

[0062] A6-2) Route calculation unit 164 Figure 7 shows the control structure of the program that implements the route calculation unit 164 shown in Figure 3. Referring to Figure 7, this program includes a step 310 to obtain the location of the destination through interaction with the user, and a step 312 to obtain information about the communication service required to receive service from the server 108 (information about the required communication speed, such as bitrate).

[0063] This program further includes a step 314 to obtain communication history information for an area including the area from the current location to the area around the destination from the communication history information DB 156 (Figure 3), a step 316 to branch the control flow according to whether or not there is a communication history management server that is linked with the in-vehicle device 102, and a step 318 to branch the control flow according to whether or not there is sufficient data from the communication history information DB 156 for route calculation when the determination in step 316 is positive.

[0064] This program further includes, when the determination in step 318 is negative, step 320, which obtains communication history information for the area from the current location to the destination from a communication history management server (in this example, the communication history management server 110 shown in Figure 2) that is in cooperation with the in-vehicle device 102, and step 322, which calculates a driving route using the obtained communication history information and provides information about the calculated driving route to the driver unit 162 to terminate the execution of the program. When the determination in step 316 is negative, and when the determination in step 318 is positive, step 320 is not executed, and the route calculation process in step 322 is executed immediately.

[0065] Figure 8 shows the control structure of the program that implements step 322 shown in Figure 7. Referring to Figure 8, step 322 includes step 350, which sets the search range for the travel route, and step 352, which generates a route graph connecting the current location and the destination based on the map information provided in the driver unit 162 within the search range. The route graph referred to here is a graph in which intersections are nodes and roads connecting intersections are edges (links). In this embodiment, each edge is accompanied by information indicating the length of the corresponding road. In this route graph, there are many routes connecting the current location and the destination.

[0066] This program further includes step 354, which searches for the shortest path from the current location to the destination in the path graph generated in step 352. In this embodiment, Dijkstra's algorithm is used to find the shortest path. Of course, any algorithm that can find the shortest path in a graph can be used, not just Dijkstra's algorithm.

[0067] The program further includes step 356, which refers to communication history information and removes edges from the route graph that include points with a bitrate less than half of the bitrate specified by the service; step 358, which searches for the shortest path in the route graph after the processing in step 356; step 360, which removes links from the route graph that include points with a bitrate less than a further specified bitrate; and step 362, which searches for the shortest path in the route graph after the processing in step 360 and terminates step 322.

[0068] Through the above process, the shortest travel route regardless of the specified bitrate, the shortest travel route that can communicate with a bitrate of at least half of the specified bitrate, and the shortest travel route that can communicate with a bitrate equal to or greater than the specified bitrate can be identified.

[0069] Figure 9 shows the control structure of the program that implements the grid drawing unit 166 shown in Figure 3. The grid diagram obtained by the grid drawing unit 166 is, for example, like the grid shown in Figure 1. In Figure 1, each grid is displayed in a different display mode depending on the communication speed available in that grid. Multiple travel routes generated in step 322 of Figure 7 are superimposed on a predetermined map, and a semi-transparent grid is further superimposed.

[0070] Referring to Figure 9, this program includes step 370, which obtains a geohash value representing the area displayed on the touch panel display device 116 and divides this area into a predetermined number of grid regions from the top left to the bottom right. In step 370, the geohash of a predetermined position (e.g., the center position) within each grid region is further calculated.

[0071] The program further includes step 372, which performs step 374 for each grid region obtained in step 370.

[0072] Step 374 includes step 380, which searches the communication history information DB156 for records that begin with the same string as the geohash of the grid area and whose time indicated by the date and time falls within a predetermined range centered on the current time, and calculates the average communication speed of those records; and step 382, ​​which quantizes the average communication speed calculated in step 380 into several stages and determines the display color (hue) and brightness of the target grid area. In this embodiment, the hue is red, and the brightness is determined as a monotonic function of the communication speed such that the brightness is low when the communication speed is low and high when the communication speed is high. In this embodiment, the brightness is set to the maximum value when the communication speed exceeds a predetermined threshold.

[0073] Step 374 further includes step 384, which ends step 374 by setting the alpha value of each grid area to a value that represents semi-transparency when displayed. In this case, the alpha value is set so that the grid with the highest brightness is displayed transparently.

[0074] B. Operation B1) Accumulation of communication records While the vehicle equipped with the on-board device 102 is in motion, the communication unit 150 periodically measures the communication speed and signal strength. When no communication is taking place, the communication unit 150 measures only the signal strength. The communication unit 150 provides this information to the communication record unit 154 as communication history.

[0075] The communication record recording unit 154 receives information indicating the vehicle's status from the sensor 112 and the GNSS receiver 114 via the CAN 152. The communication record recording unit 154 generates communication record information from the communication record received from the communication unit 150 and the information representing the vehicle's status, and stores it in the communication record information DB 156.

[0076] B2) Enter destination When a user is heading to a destination, they interact with the touch panel display device 116 to display the initial route setting screen and specify the destination and the services to be used. In step 310 of Figure 7, the in-vehicle device 102 acquires the destination specification and identifies its location. In step 312, the route calculation unit 164 acquires information about the communication services required by the service specified by the user (step 312). As a result of this process, the required bitrate is determined.

[0077] The route calculation unit 164 further obtains communication history information for the area connecting the current location and the destination from the communication history information DB 156 (step 314 in Figure 7). If there is no communication history management server linked to the in-vehicle device 102 (the determination in step 316 in Figure 7 is negative), the route calculation unit 164 executes the route calculation process (step 322 in Figure 7). If there is a communication history management server linked to the in-vehicle device 102 (the determination in step 316 in Figure 7 is positive), it determines whether the communication history obtained from the communication history information DB 156 is sufficient to determine the driving route based on the bit rate determined in the target area (step 318). If the determination in step 318 is positive, the route calculation unit 164 calculates the driving route using only the communication history obtained from the communication history information DB 156 (step 322). If the determination in step 318 is negative, the route calculation unit 164 instructs the communication history acquisition unit 160 to obtain communication history information for the target area from the communication history management server 110. The communication record acquisition unit 160 adds the acquired communication record information to the communication record information DB 156, and the route calculation unit 164 retrieves the communication record information again from the communication record information DB 156 and then calculates the travel route using the retrieved communication record information (step 322).

[0078] B3) Route Calculation The route calculation unit 164 of the in-vehicle device 102 calculates the travel route as follows. Referring to Figure 8, the search range for the travel route is determined based on the relationship between the current position and the destination (step 350). Various methods can be considered for determining this search range. In this embodiment, the search range is defined as a rectangle with the line connecting the current position and the destination as its diagonal. Of course, the search range is not limited to this, and various other methods can be considered.

[0079] Next, the route calculation unit 164 generates a route graph based on information about each intersection within the search range determined in step 350 and the roads connecting those intersections (step 352). At this time, roads with a width smaller than a certain value may be excluded from the route graph.

[0080] The route calculation unit 164 applies Dijkstra's algorithm to the route graph generated in this way to generate a travel route consisting of the shortest path from the current location to the destination (step 352). The communication speed along the way is not taken into consideration when generating the travel route at this time. In other words, the travel route generated in step 352 is the shortest path when the user chooses not to receive communication services.

[0081] In step 356, the route calculation unit 164 further removes edges with a communication speed of less than half of the specified bitrate from the route graph. As a result, the remaining edges will have a bitrate of half or more of the specified bitrate. In step 358, the route calculation unit 164 searches for the shortest path in this route graph. This path is the shortest path among the routes that are expected to be usable with a bitrate of half or more of the specified bitrate.

[0082] In step 360, the route calculation unit 164 further removes edges with a bitrate lower than the specified bitrate from the route graph. In the following step 362, it searches for the shortest path in the remaining route graph. The route obtained through this process is the shortest route among those routes where a communication speed of at least the specified bitrate is expected.

[0083] In this way, multiple travel routes are calculated based on the constraints specified by the user.

[0084] It should be noted that the constraints are not limited to those mentioned above, and various other constraints are possible. For these constraints, for example, a program consisting of a series of procedures like steps 352 and 354 in Figure 8 can be prepared, and the appropriate program can be executed based on the user's specifications. Preferably, the execution order of the programs should also be specified in advance. By executing the programs according to such specifications, the amount of computation required to calculate the travel route can be reduced.

[0085] B4) Display of route suggestion screen Once the travel route is calculated through the process described above, the driver unit 162 generates the route suggestion screen 50 shown in Figure 1 and displays it on the touch panel display device 116. The driver unit 162 first displays a map of the relevant area. The driver unit 162 then displays the three calculated travel routes superimposed on the map. The travel routes can be displayed by continuously drawing rectangles connecting the start and end points of each edge that forms the travel route.

[0086] The grid drawing unit 166 creates a grid display as shown in Figure 1 as follows. Referring to Figure 9, the grid drawing unit 166 obtains a geohash value representing the area displayed on the touch panel display device 116 and divides this area into a predetermined number of grid regions from the top left to the bottom right (step 370). At this time, the geohash of a predetermined position (for example, the center position) within each grid region is calculated.

[0087] The grid drawing unit 166 further performs the following step 374 for each grid region.

[0088] In step 374, the grid drawing unit 166 searches the communication history information DB 156 for records that begin with the same string as the geohash of the target grid area and whose time indicated by the date and time falls within a predetermined range centered on the current time, and calculates the average communication speed of those records (step 380). The grid drawing unit 166 further quantizes the average communication speed calculated in step 380 into several stages and determines the display color (hue) and brightness of the target grid area (step 382). In this embodiment, the hue is red, and the brightness is determined as a monotonic function of the communication speed such that the brightness is low when the communication speed is low and high when the communication speed is high.

[0089] The grid drawing unit 166 further sets a value representing semi-transparency for the alpha value when displaying each grid area (step 384). At this time, the grid drawing unit 166 sets the alpha value so that grids with maximum brightness are displayed transparently. The grid area images created in this way are superimposed on the map and driving route images in the driving unit 162. As a result, as shown in Figure 1, the map, driving route, and grid are superimposed and displayed on the display surface of the touch panel display device 116. In areas with high communication speed, the map is displayed as is. In areas with low communication speed, a semi-transparent red area with brightness according to the communication speed is displayed on top of the map. The lower the communication speed, the darker the red each area is displayed in, and the higher the communication speed, the brighter the red it is displayed in.

[0090] As described above, according to this embodiment, the communication speeds actually measured in the past are stored in the communication history information DB156 and used to calculate the travel route. As a result, an appropriate travel route can be calculated according to the bitrate required by the service being used. When calculating the travel route, multiple travel routes are calculated based on the constraints specified by the user. The user can select the appropriate travel route depending on how they will use the service.

[0091] Furthermore, the communication speed status in the area surrounding the current location and destination is visually displayed. Therefore, users can select an appropriate route based on their purpose for using the service, the communication status, and the distance to their destination, such as how well communication services are available during their journey from their current location to their destination, and what route would be best to take to fully utilize the services.

[0092] Furthermore, the communication history management server 110 stores communication history information from each vehicle. Therefore, when calculating a driving route in a certain in-vehicle device, if sufficient communication history information is not stored in the in-vehicle device, the necessary communication history information can be retrieved from the communication history management server 110. As a result, the optimal driving route for using communication services can be calculated across a wide range of areas.

[0093] In the first embodiment described above, the user is asked to select one of the three travel routes displayed on the touch panel display device 116. However, this disclosure is not limited to such embodiments. Embodiments are also possible in which a travel route is selected that always maintains the requested communication speed, or, if such a route does not exist, the travel route with the highest average communication speed along the way is automatically selected.

[0094] 2. Second Embodiment A.Configuration A1) Vehicle support system 400 Figure 10 shows the configuration of the vehicle support system 400 according to the second embodiment. Referring to Figure 10, the vehicle support system 400 according to the second embodiment includes a server 108, in-vehicle devices 402, 404, and 406 that utilize services provided by the server 108, and a communication record management server 408 that stores communication record information from multiple in-vehicle devices such as the in-vehicle device 402 and transmits the communication record information to each in-vehicle device as requested.

[0095] In this embodiment, unlike the first embodiment, the route calculation unit is not located in the in-vehicle device 402, but is located in the communication history management server 408.

[0096] A2) In-vehicle device 402 Referring to Figure 11, the in-vehicle device 402 differs from the in-vehicle device 102 shown in Figure 3 in that it does not include the communication history acquisition unit 160 and the route calculation unit 164.

[0097] Furthermore, the driver unit 162 differs from the driver unit 162 shown in Figure 3 in that, based on destination information entered by the user using the touch panel display device 116, it requests the necessary communication history information from the communication history management server 408, rather than from the communication history information DB 156.

[0098] A3) Communication performance management server 408 Referring to Figure 12, the communication performance management server 408 includes a communication performance acquisition unit 450 that acquires communication performance information from multiple in-vehicle devices, a communication performance information storage unit 202 for storing the communication performance information acquired by the communication performance acquisition unit 450, and a route calculation unit 452 that receives a request to calculate a driving route specifying the current location and destination from the driving unit 162 of an in-vehicle device such as the in-vehicle device 402 shown in Figure 10, reads the communication performance information for the corresponding area from the communication performance information storage unit 202, and transmits it to the in-vehicle device 402.

[0099] B. Operation In this second embodiment, the only difference is that when a destination is entered via the touch panel display device 116, the driver unit 162 requests communication history information from the route calculation unit 452 of the communication history management server 408, specifying the current location and destination, rather than from the communication history information DB 156, and the route calculation unit 452 responds to this request by reading the communication history information from the communication history information storage unit 202 in the corresponding area and transmitting it to the driver unit 162. In all other respects, each functional unit of the vehicle support system 400 operates in the same manner as the corresponding functional unit in the first embodiment.

[0100] 3. Third Embodiment A.Configuration A1) Vehicle support system 500 Referring to Figure 13, the vehicle support system 500 according to the third embodiment of this disclosure includes a server 108, in-vehicle devices 502, 504, and 506, and a communication performance management server 110. The server 108 and the communication performance management server 110 are the same as the server 108 and the communication performance management server 110 in the first embodiment shown in Figure 2.

[0101] A2) In-vehicle device 502 Referring to Figure 14, the in-vehicle device 502 is similar to the in-vehicle device 102 shown in Figure 3. However, unlike the in-vehicle device 102, the in-vehicle device 502 includes a communication performance comparison unit 552 that receives measurement results regarding the current communication speed from the communication performance recording unit 154, compares them with the communication speed estimated from the information stored in the communication performance information DB 156, calculates the difference between the two, and outputs that value. 5 02 also includes a communication unit 550, instead of the communication unit 150 shown in Figure 3, which has the function of adjusting the bitrate for the service received from the server 108 in response to the magnitude of the difference output by the communication performance comparison unit 552 being greater than a threshold. If the actual speed measured by the communication performance recording unit 154 is less than or equal to the predicted speed by a threshold, the communication unit 550 requests the server 108 to reduce the bitrate of the service using the server 108. As a result, if the service provided by the server 108 is something like a video stream, the server 108 will either lower the resolution of the video or reduce the number of transmitted frames so that the service can continue to be used. Conversely, if the actual measured value is greater than or equal to the predicted value by a threshold, the communication unit 550 requests the server 108 to increase the bitrate used for the service if possible.

[0102] The in-vehicle device 502 further includes a route calculation unit 556, which replaces the route calculation unit 164 shown in Figure 3, and in addition to the functions of the route calculation unit 164, has the function of recalculating the route when the absolute value of the value output by the communication performance comparison unit 552 is greater than a threshold. The in-vehicle device 502 further includes a communication performance transmission unit 554, which replaces the communication performance transmission unit 158 ​​shown in Figure 3, and in addition to the functions of the communication performance transmission unit 158, has the function of immediately transmitting communication performance information created from the latest measurement results measured by the communication performance recording unit 154 to the server 108 when the absolute value of the value output by the communication performance comparison unit 552 is greater than or equal to a threshold.

[0103] A3) Communication Performance Comparison Section 552 Figure 15 shows the control structure of the program that implements the communication performance comparison unit 552. Referring to Figure 15, this program includes a step 600 that repeatedly executes step 602.

[0104] Step 602 includes step 610, which receives the latest measured value of the communication speed from the communication history recording unit 154; step 612, which reads past communication history information at the current location from the communication history information DB 156; and step 614, which branches the control flow according to whether the difference between the latest measurement result and the communication speed in the communication history read in step 612 is greater than or equal to a threshold. If the determination in step 614 is negative, the processing of the latest measurement result in step 602 is terminated.

[0105] This program further includes, when the determination in step 614 is positive, step 616 immediately transmits communication performance information obtained from the latest measurement results to the communication performance management server 110; step 618 changes the communication quality with the server 108 by controlling the communication unit 550 based on the latest measurement results; and step 620 terminates the execution of step 602 by executing a route change that recalculates the travel route by controlling the route calculation unit 556. In this embodiment, the result of the route change is not presented to the user and is immediately reflected in the operation of the driving unit 162.

[0106] B. Operation Referring to Figure 14, the communication unit 550, like the communication unit 150 in other embodiments, periodically measures the communication speed and signal strength when communication is in progress, and only the signal strength when communication is not in progress, and provides the measurement results to the communication record recording unit 154. The communication record recording unit 154 operates in the same manner as in Figure 3. However, the communication record recording unit 154 also provides the latest communication record to the communication record comparison unit 552.

[0107] The communication performance comparison unit 552 receives the latest communication performance from the communication unit 550 (step 610 in Figure 15), reads past communication performance at that location from the communication performance information DB 156 based on the current location of the in-vehicle device 502, and subtracts the speed of the past communication performance from the latest measured speed (step 612). If the absolute value of the subtraction result is greater than the threshold (the judgment in step 614 is positive), the communication performance comparison unit 552 provides the communication performance based on the latest measurement result to the communication performance transmission unit 554 (step 616). The communication performance comparison unit 552 further provides the subtraction result from step 614 to the communication unit 550 (step 618). Similarly, the communication performance comparison unit 552 provides the communication performance based on the latest measurement result to the route calculation unit 556 (step 618).

[0108] As a result, the communication record transmission unit 554 immediately transmits the communication record based on the latest measurement results to the communication record management server 110. The communication record management server 110 stores the received communication record in the communication record information storage unit 202 (see Figure 4). The communication unit 550 requests the server 108 to adjust the bitrate of the service provided by the server 108 based on the latest measurement results. The route calculation unit 556 recalculates the travel route based on the latest measurement results and controls the driving unit 162 to change the travel route according to the result.

[0109] As described above, according to this third embodiment, if the latest measurement result regarding communication speed differs significantly from past communication records, the latest measurement result is immediately sent to the communication record management server 110 as a communication record. As a result, the latest measurement result is immediately reflected in the communication record management server 110. Similarly, the communication unit 550 changes the bitrate of the service received from the server 108 according to the communication speed based on the latest measurement result. As a result, if the communication speed decreases, the service is also changed to a service with a correspondingly lower bitrate. Conversely, if the communication speed increases, the service is also changed to a service with a correspondingly higher bitrate. For example, in the case of video streaming, the service can be maintained by changing the image resolution or frame rate according to the available communication speed in this way. In addition, by automatically changing the route, a course that provides better communication quality is selected. As a result, users can use the service under better conditions.

[0110] 4. Fourth Embodiment A.Configuration A1) Driver assistance system 650 Referring to Figure 16, the driver assistance system 650 according to the fourth embodiment of this disclosure includes a server 108, in-vehicle devices such as in-vehicle devices 652, 654, and 656, and a communication performance management server 658.

[0111] The in-vehicle device 652 according to the fourth embodiment differs from the in-vehicle device 102 shown in Figure 3 in that, in addition to the functions of the in-vehicle device 102, it performs statistical processing on the communication history stored in the communication history information DB 156 and proposes driving routes based on the results. In this statistical processing, values ​​indicating that communication was not possible (for example, "-1") are excluded from the calculation of so-called average values. However, they are included in the count when calculating statistical information regarding whether or not communication was possible.

[0112] A2) In-vehicle device 652 Referring to Figure 17, the in-vehicle device 652, as described above, includes, in addition to the parts of the in-vehicle device 102 shown in Figure 3, a communication statistics calculation unit 700 that performs predetermined statistical processing on the communication performance information stored in the communication performance information DB 156, a communication performance statistics information DB 702 for storing statistical information about communication calculated by the communication statistics calculation unit 700, and a route calculation unit 704 that calculates a driving route using the communication performance statistics information stored in the communication performance statistics information DB 702.

[0113] In this embodiment, when the communication record acquisition unit 160 receives a request from the route calculation unit 704 to acquire communication record information, it provides the route calculation unit 704 with communication record statistics stored in the communication record statistics information DB 702, rather than the communication record information DB 156. If the route calculation unit 704 has difficulty calculating the travel route based on the communication record statistics information stored in the communication record statistics information DB 702, the communication record acquisition unit 160 receives the communication record statistics information stored in the communication record statistics information DB 702 from the communication record management server 658. The communication record acquisition unit 160 then receives this communication record information... Total The information is added to the communication performance statistics database DB 702 and then provided to the route calculation unit 704. The route calculation unit 704 differs from the route calculation unit 164 in that the communication performance used when calculating the travel route is not the measured information stored in the communication performance information DB 156, but rather the statistically processed information stored in the communication performance statistics database DB 702.

[0114] A3) Communication performance management server 658 Referring to Figure 18, the communication performance management server 658 includes a communication performance acquisition unit 200, a communication performance information storage unit 202, and a communication statistics calculation unit 720 for performing statistical processing on the communication performance information stored in the communication performance information storage unit 202, similar to the communication statistics calculation unit 700 shown in Figure 17. The communication performance management server 658 further includes a communication performance statistics information storage unit 722 for storing statistical information about communication performance calculated by the communication statistics calculation unit 720, and a communication performance transmission unit 724 for reading communication performance statistics information corresponding to the current location specified by the communication performance acquisition unit 160 from the communication performance statistics information storage unit 722 and transmitting it to the communication performance acquisition unit 160 in response to a request from the communication performance acquisition unit 160 shown in Figure 17.

[0115] Figure 19 shows the column configuration of the communication performance statistics information DB 702 shown in Figure 17. The communication performance statistics information storage unit 722 shown in Figure 18 has a similar column configuration.

[0116] Referring to Figure 19, the communication performance statistics DB702 has a date and time column, a grid ID column, a communication speed column, a speed column, a direction column, a communication line column, a communication carrier column, a band number column, a cell ID column, and the same SINR, RSSI, RSRP, and RSRQ columns as shown in Figure 5.

[0117] Of the information stored in each of these columns, the date and time column is used to identify the unit period covered by the statistics. For example, if the date and time column contains a value indicating the year (e.g., "2022"), it indicates that the statistics for the entire year of 2022 are contained in one record in the Communication Performance Statistics Information DB702. If the date and time column contains information indicating a month (e.g., "202206"), it indicates that the statistics for that month are stored in that one record. Similarly, using the date and time column, statistics for daily periods, hourly periods, etc., can each be stored as one record in the Communication Performance Statistics Information DB702. By including date and time information in the records in this way, statistical information can be recorded hierarchically over various periods.

[0118] The grid ID is a geohash identifier that identifies the grid being statistically analyzed. This value is fixedly assigned to each grid. However, as mentioned above, the grid ID also has a hierarchical structure. Therefore, even for grids, by determining the smallest unit of size and recording the statistical values ​​of the communication status within that grid, statistics for larger grids can be calculated at any given time. In this way, by using the values ​​in the date and time column and the grid ID column, statistical information can be calculated and recorded with a geographical and temporal hierarchical structure.

[0119] In Figure 19, the columns below the communication speed are values ​​after statistical processing. The method of statistical processing for each of these columns differs depending on the column. For example, for communication speed, speed, direction, and SINR, RSSI, RSRP, and RSRQ, one of the representative values ​​obtained by statistical processing, such as the mean, maximum, minimum, and CDF (cumulative distribution function), or any combination thereof, is stored. For direction, the direction may be quantified and its average taken, or 360 degrees may be divided into predetermined angles and the number of values ​​that fall within each angle range may be counted. Communication line, communication carrier, band number, and cell ID are all discrete values, but for these, the values ​​should be recorded by counting the types used within the target unit period.

[0120] Figure 20 shows the control structure of the program that makes the computer function as the communication statistics calculation unit 720 shown in Figure 18. This program is started by receiving a parameter 730 as an argument that specifies the granularity of the period to be calculated and the granularity when dividing the area into a grid. This program calculates communication performance statistics for each period and area of ​​the specified granularity. In this specification, "high granularity" means that the unit to be processed is large, and "low granularity" means that the unit to be processed is small. Of course, "high" and "low" granularity are relative expressions.

[0121] This program includes a step 732 that confirms the current time and the range (full area range) that covers the entire location where the information communication record information stored in the communication record information storage unit 202 was acquired. In the fourth embodiment, the full area range is a rectangle and is specified by the coordinates (latitude and longitude) of its northwest and southeast ends. Of course, the shape used to specify the full area range is not limited to a rectangle. Any shape can be used, including circles or ellipses, which are not composed of straight lines.

[0122] This program further includes a step 734 to determine the target period by dividing the period for statistical calculation according to parameter 730, and a step 736 to determine the set of target areas for statistical calculation by dividing the entire area range according to a specified granularity according to parameter 730.

[0123] In step 734, the unit period including the current time obtained in step 732 and the immediately preceding unit period are generally considered. However, if, for example, the statistical calculation has already been completed and it has been determined that no further updates will be made, the immediately preceding unit period will not be included in the statistical calculation.

[0124] For example, if the granularity of the date and time is "days," and the current date is "September 1, 2022," then both "September 1, 2022," which includes the current time, and the immediately preceding day, "August 31, 2022," will be included in the statistical calculation. However, if, for example, the statistical calculation for "August 31, 2022" has been completed and it has been confirmed that it will not be updated, then only "September 1, 2022" will be included in the statistical calculation.

[0125] If the date and time granularity is "hours," and the current date and time is "September 1, 2022, 11:05:17," then both "September 1, 2022, 11:00" and "September 1, 2022, 10:00" will be included in the statistical calculation. However, if the statistical calculation for "September 1, 2022, 10:00" has already been finalized, then only "September 1, 2022, 11:00" will be included in the statistical calculation.

[0126] In step 736, the entire area of ​​the rectangle confirmed in step 732 is divided into rectangular regions of the size specified by parameter 730. Each of these divided regions is then assigned a unique geohash code, as described above.

[0127] This program further includes step 738, which performs step 740 for each unit period included in the target period determined in step 734. As mentioned above, the unit periods included in the target period are basically one unit period including the current time, or two unit periods including the most recent unit period.

[0128] Step 740 includes step 742, which performs step 744 for each target area divided in step 736.

[0129] Step 744 includes step 750, which reads communication performance information from the communication performance information storage unit 202 shown in Figure 18 using the target period and target area as keys, and step 752, which calculates each statistical information shown in the communication performance statistics DB 702 based on the communication performance information read in step 750. Different processing is performed for each item when calculating the statistical information in step 752. Note that if a relational database is used for the communication performance statistics DB 702, the processing in step 732 may be simplified by including commands to calculate representative statistical values ​​such as mean, maximum, minimum, or variance in the query when reading the records.

[0130] Step 744 further includes step 754, which branches the control flow depending on whether a record with the same key used in step 750 exists in the communication performance statistics information storage unit 722. Step 744 further includes step 756, which, if the determination in step 754 is positive, updates the record with that key according to the latest statistical value calculated in step 752 and terminates step 744; and step 758, if the determination in step 754 is negative, adds a new record to the communication performance statistics information storage unit 722 with the target period and target region used in step 750 as keys and the statistical value calculated in step 752 as content, and terminates step 744.

[0131] The above explanation pertains to the program executed by the communication statistics calculation unit 720 of the communication performance management server 658 shown in Figure 18. On the other hand, the communication statistics calculation unit 700 of the in-vehicle device 652 shown in Figure 17 also executes a program with essentially the same control structure as that shown in Figure 20. However, in the case of the in-vehicle device 652, the target area is limited, and the size of the grid used when proposing routes is also limited. Therefore, the granularity of the date and time and the granularity of the range division are made relatively high when executing a program similar to that shown in Figure 20. As a result, even a device like the in-vehicle device 652, which is not blessed with many computing resources, can reliably calculate communication statistics.

[0132] Figure 21 shows the control structure of the program that causes the computer to function as the communication record transmission unit 724 shown in Figure 18. This program is started whenever the communication record management server 658 receives a request to transmit communication record statistics from an external device.

[0133] Referring to Figure 21, this program includes step 780, which extracts information from the received transmission request message indicating the date and time to be transmitted, the granularity of the date and time, the range, and the granularity of the range. If no date and time is specified, the most recent unit of time is assumed to be specified. In this case, the unit of time is determined by the granularity of the date and time. If no granularity of date and time is specified, the default unit of time, for example, 1 hour, is used. A range is required. The granularity of the range is specified, for example, by the number of digits in the geohash used. If no granularity of the range is specified, the granularity of the range is defined as a function of the size of the specified range.

[0134] This program further includes, following step 780, step 782, which reads records from the communication performance statistics information storage unit 722 corresponding to the date and time, date and time granularity, range, and range granularity extracted in step 780, and step 784, which formats the information contained in the records read in step 782 into a predetermined format and transmits it to an external device in one or more packets to terminate the execution of this program.

[0135] B. Operation In this embodiment, the communication record recording unit 154 of the in-vehicle device 652 shown in Figure 17 periodically acquires communication record information and stores it in the communication record information DB 156. The communication record transmission unit 158 ​​similarly transmits the communication record information to the communication record management server 658. The communication record acquisition unit 200 of the communication record management server 658 shown in Figure 18 acquires communication record information from multiple in-vehicle devices, including the in-vehicle device 652, and stores it in the communication record information storage unit 202.

[0136] Referring to Figure 17, in the fourth embodiment, in the in-vehicle device 652, the communication statistics calculation unit 700 performs statistical processing on the communication performance information stored in the communication performance information DB 156 according to a certain schedule, and stores the results in the communication performance statistics information DB 702.

[0137] In this case, the schedule could be to perform statistical processing only once each time the minimum time unit described above has elapsed, or it could be to perform statistical processing every time a predetermined period longer than the minimum time unit has elapsed. However, in the fourth embodiment, it is necessary to obtain hierarchical statistics. In such cases, when performing statistical processing, not only the processing for the minimum time unit but also higher-level statistics are calculated. When calculating higher-level statistics, they may be calculated directly from the information stored in the communication performance information DB 156, or lower-level statistical information stored in the communication performance statistics information DB 702 may be used. In the fourth embodiment, as described above, the communication statistics calculation unit 700 uses only the information from the communication performance information DB 156. Also, the load of statistical calculation processing by the communication statistics calculation unit 700 is smaller compared to the communication statistics calculation unit 720. On the other hand, the statistical information stored in the communication performance statistics information DB 702 is information obtained from information in a relatively limited area, and is limited to statistical information with a higher granularity compared to the statistical information stored in the communication performance statistics information storage unit 722, both in terms of time and geography.

[0138] On the other hand, in the communication performance management server 658 shown in Figure 18, similar to the in-vehicle device 652, the communication statistics calculation unit 720 performs statistical processing on the communication performance information stored in the communication performance information storage unit 202 according to a fixed schedule, and stores the obtained communication performance statistics information in the communication performance statistics information storage unit 722.

[0139] For example, when performing statistical processing on a daily basis, a cycle of approximately 24 or 12 hours is typically used, and the program shown in Figure 20, with its control structure, is launched for each region at each level of the scope being managed. For example, if 12 hours is used as one cycle for statistical processing, the 24-hour information will be processed twice. In the first processing, the statistical information for the first 12 hours is calculated. In the second processing, the 24-hour statistical information is calculated, and the statistical information calculated based on the 12-hour information is updated with that information.

[0140] The program shown in Figure 20 can be launched multiple times simultaneously, enabling parallel processing. When the granularity of the date and time used in calculating statistical information decreases, and the range expands and the granularity of the range decreases, the number of data points for statistical calculation becomes very large. In such cases, statistical processing can be performed on multiple processors, and each processor can further perform parallel computing using a GPU, allowing the necessary statistical processing to be executed in a timely manner. The computing resources available to the communication performance management server 658 can be increased according to demand. As a result, it becomes possible to respond flexibly even when demand from external devices increases.

[0141] When the route calculation unit 704 calculates a travel route, it specifies the current location and destination and requests the communication record acquisition unit 160 to acquire communication records for the relevant area. The communication record acquisition unit 160 selects communication record statistics information for the specified area from the information stored in the communication record statistics information DB 702 and inputs it to the route calculation unit 704. If the information obtained from the communication record statistics information DB 702 is sufficient to calculate the travel route in the specified area, the route calculation unit 704 immediately executes the route calculation process; otherwise, it requests the communication record acquisition unit 160 to acquire communication record statistics information for the specified area from the communication record management server 658. The communication record acquisition unit 160 sends a request to the communication record transmission unit 754 of the communication record management server 658 to transmit statistical information so that the requested information can be obtained.

[0142] This transmission request includes information specifying the temporal range and geographical range for which statistical information is needed, as well as information specifying the granularity of those ranges. For example, if information is needed for a range not covered by the statistical information stored in the communication statistics calculation unit 700, the communication performance acquisition unit 160 requests statistical information for at least that range from the communication performance management server 658. If the information stored in the communication statistics calculation unit 700 does not allow for the determination of detailed regional communication conditions, the communication performance acquisition unit 160 requests statistical information for lower-granularity divided areas from the communication performance management server 658.

[0143] When the communication record transmission unit 724 of the communication record management server 658 shown in Figure 18 receives this transmission request, it executes the program shown in Figure 21. That is, the communication record transmission unit 724 extracts information from the transmission request message indicating the date and time to be transmitted, the granularity of the date and time, the range, and the granularity of the range (step 780). If this information is not specified, the communication record transmission unit 724 uses default values ​​as described above. The communication record transmission unit 724 reads the record corresponding to the information obtained from the transmission request in this way from the communication record statistics information storage unit 722 (step 782).

[0144] When the received transmission request contains specific communication device information, communication line information, or communication carrier information, the communication performance transmission unit 724 reads information from the communication performance statistics database 702 and extracts only records (communication environment information) that have matching communication device information, communication line information, and communication carrier information. The communication performance transmission unit 724 further statistically processes the values ​​related to communication quality metrics of these records and calculates statistically representative values.

[0145] The communication record transmission unit 724 formats the information contained in the read record, or the statistically processed information, into a predetermined format and transmits it to the communication record acquisition unit 160 of the in-vehicle device 652 in one or more packets (step 784).

[0146] The communication record acquisition unit 160 receives this statistical information from the communication record transmission unit 724 and adds it to the communication record statistics information DB 702 shown in Figure 17. The added information is input from the communication record statistics information DB 702 to the route calculation unit 704. The route calculation unit 704 uses the communication record statistics information obtained in this way to calculate the route from the current location to the destination according to the specified conditions.

[0147] The operation of all other parts is the same as that of the in-vehicle device in the first to third embodiments.

[0148] C. Variations In the fourth embodiment, statistical metrics based on the communication environment, such as communication devices, communication lines, or communication carriers, are not calculated. This is because these are inherently numerous and subject to change, making them unsuitable for continuous statistical calculation. Furthermore, subdividing communication performance information using such information would increase the computational load required for statistical processing. However, if, for example, the in-vehicle device 652 uses a specific communication device, communication line, or communication carrier, it is considered that using statistical metrics that take these into account would increase the reliability of the communication status estimation.

[0149] In this modified example, the communication performance management server normally operates in the same manner as in the fourth embodiment, but if the transmission request includes information about the communication environment, it extracts only the records that match the specified conditions from the details of the communication performance information stored in the communication performance information storage unit 202, rather than the statistical information stored in the communication performance statistical information storage unit 722. The retrieved records are subjected to statistical processing, and the results are transmitted to the in-vehicle device.

[0150] Figure 22 shows a block diagram of the communication performance management server 790 of this modified example. The communication performance management server 790 differs from the communication performance management server 658 shown in Figure 18 in that, instead of the communication performance transmission unit 724 shown in Figure 18, it includes a communication performance transmission unit 792 that receives transmission requests and performs different processing depending on whether or not the transmission request is accompanied by information about the communication environment. Normally, the communication performance transmission unit 792 reads information from the communication performance statistics information storage unit 722 and transmits it to the in-vehicle device, similar to the communication performance transmission unit 724 in the fourth embodiment. However, if the transmission request includes information about the communication environment (for example, a communication line or a communication carrier or a combination thereof), the communication performance transmission unit 792 performs different processing.

[0151] The communication performance management server 790 further includes an on-demand communication statistics processing calculation unit 794 that, when information regarding the communication environment is attached to a transmission request, responds to instructions from the communication performance transmission unit 792 and reads a record from the communication performance information storage unit 202 containing the date and time and range specified, as well as communication environment information consistent with the information regarding the communication environment, and simultaneously performs statistical processing on the read record regarding communication quality metrics and returns it to the communication performance transmission unit 792.

[0152] In other words, when information regarding the communication environment is attached to the transmission request, the communication performance transmission unit 792 does not obtain information from the communication performance statistics information storage unit 722, but rather obtains information from the communication statistics processing calculation unit 794 as needed.

[0153] With this configuration, the communication performance management server 790 in this modified version can normally use the information from the communication performance statistics information storage unit 722 to transmit communication quality metrics to the in-vehicle device at high speed. In addition, when the transmission request is accompanied by information that identifies the communication environment, the communication performance management server 790 can transmit communication quality metrics obtained only from communication performance that matches that specific communication environment to the in-vehicle device. As a result, it is possible to improve the accuracy of the statistical quality metrics transmitted to the in-vehicle device while preventing an increase in the load of statistical processing.

[0154] 5. Fifth Embodiment The fifth embodiment is characterized by the display method when a driving route is proposed. The configuration of the in-vehicle device for this purpose is the same as, for example, the in-vehicle device 102 shown in Figure 3. However, in this embodiment, the grid is not superimposed on the map as shown by the grid drawing unit 166 in Figure 3. Instead, in the fifth embodiment, as shown in Figure 23, a proposed driving route display unit (not shown) is used, which displays the proposed driving route in different ways depending on the communication speed that is assumed to be available at each grid that the driving route passes through.

[0155] Referring to Figure 23, in the fifth embodiment, the display 800 of the touch panel display device 116 includes a driving route display 810, a first route prediction image display 812, and a second route prediction image display 814.

[0156] The route display 810 shows a map, and the current location and destination of the vehicle image 816 are superimposed on the map as callouts 820 and 822. No grid is displayed. Instead, each part of the route images 830 and 832 is displayed with a hue and brightness corresponding to the communication speed in the grid to which that part belongs. Typically, the hue is red, and the brightness is adjusted according to a monotonic function of the communication speed, becoming higher for higher communication speeds and lower for lower communication speeds. However, due to the constraints of the drawing, such changes in display mode are not shown in Figure 23.

[0157] Furthermore, in the fifth embodiment, a representative value of the communication speed (e.g., average bitrate, the ratio of the route length at which the minimum bitrate specified by the service can be used to the total route) is displayed in association with each route. An example of this is the "communication quality satisfaction" shown by callouts 824 and 826 in Figure 23. For example, according to callout 824, the communication quality satisfaction for the first route (the first travel path) is 75%. This means that in the first route, the total route length at which the bitrate specified by the service can be maintained corresponds to 75% of the total length of the first route. In the second route, this value is 25%. In other words, in the first route, the service can be used at the highest expected quality for 3 / 4 of its total length, but in the second route, it can only be used for 1 / 4. Displaying such representative values ​​makes it easier for users to understand the communication quality for each route.

[0158] The first route prediction image display 812 and the second route prediction image display 814 represent the expected image quality of the images displayed along each route, when the service used while traveling along each route is video streaming. In this example, sample images are prepared in advance. The expected image quality is represented by an image in which the number of pixels of the sample image is reduced according to the ratio of the representative value of the predicted communication speed when traveling along each route to the communication speed at which the image can be received at its original resolution. As described above, if the communication quality for each route is represented numerically, users can understand the differences, but it is difficult for them to grasp the differences intuitively. However, as shown by the first route prediction image display 812 and the second route prediction image display 814, representing the communication quality for each route as differences in images makes it easier for users to intuitively grasp the differences in communication quality. In this example, a callout is used, but instead of a callout, for example, a line connecting the communication quality display and the corresponding route could be displayed to associate the route with the communication quality display.

[0159] It is desirable to present these effects to users in a way that is appropriate for the type of service. For example, if the service a user intends to use is audio-related rather than video-related, it might be possible to superimpose noise corresponding to the communication speed onto a sample audio or music sample instead of a sample image.

[0160] Figure 24 shows the control structure of a computer program that implements the route suggestion processing unit described above with respect to the fifth embodiment. Referring to Figure 24, this program includes a step 850 to set a destination, a step 852 to obtain the current position of the vehicle, and a step 854 to receive from the user the specification of constraints when calculating the route.

[0161] This program further progresses to step 85 4The process includes: step 856, which searches for a travel route from the current location to the destination specified in steps 850 and 852 under the constraints specified in step 856; step 858, which displays each of the travel routes searched in step 856 as shown in the travel route display 810 in Figure 23; step 860, which calculates a representative value representing the communication quality for each of the travel routes; and step 862, which displays the representative value calculated in step 860 for each of the travel routes together with the corresponding callouts 824 and 826 having protrusions that are in contact with the travel route.

[0162] This program further includes step 864, which determines whether or not to display an image to represent the communication quality, such as when the service is related to video, and branches the control flow according to the result; step 866, which, if the determination in step 864 is positive, processes pre-prepared sample images based on representative values ​​calculated in step 860 for each travel route; and step 868, which displays the sample images processed in step 866 at a predetermined position on the travel route display 810, as shown by the first route prediction image display 812 and the second route prediction image display 814 in Figure 23, and terminates the execution of this program. If it is determined in step 864 that image display is unnecessary, steps 866 and 868 are not executed.

[0163] Referring to Figure 25, step 858 in Figure 24 includes step 900, which performs the same grid drawing process as shown in Figure 9, and step 902, which performs step 904 for each of the grids obtained in step 900.

[0164] Step 904 includes step 910, which calculates the overlapping portion between the grid to be processed and each travel path, and step 912, which sets the alpha value of each pixel so that the overlapping portion calculated in step 910 is displayed semi-transparently and the other portion is displayed transparently, and then terminates step 904.

[0165] This process causes the parts of the grid that do not overlap with the driving route to be displayed transparently; in other words, the map is displayed as is. For the parts of the grid that overlap with the driving route, the overlapping parts are displayed with the hue and brightness set in step 900, but the parts that do not overlap are displayed transparently. As a result, each part of each driving route is displayed in a different manner (hue and brightness) according to the communication quality (communication speed) in that part. The map is displayed in the parts other than the driving route. In other words, a display like the driving route display 810 in Figure 23 is obtained.

[0166] As described above, this fifth embodiment also visually displays the communication quality along the proposed route, allowing the user to select the optimal route based on the service they intend to use and the time required to reach their destination.

[0167] 6. Implementation by computer A) Hardware of the in-vehicle device The in-vehicle device related to this disclosure, as shown in Figure 2 and other figures, includes a communication device and a Microcontroller Unit (MCU) that includes a memory device for storing programs executed by the MCU. Each component of the MCU is hardware. Figure 26 shows the configuration of the MCU950 in block form.

[0168] Referring to Figure 26, the MCU950 includes a processor MPU952, a high-speed bus 978 to which the MPU952 is connected, an SRAM954 connected to the high-speed bus 978, a flash memory 956 connected to the high-speed bus 978, and a ROM958 connected to the high-speed bus 978. The SRAM954 holds data necessary for program execution. The flash memory 956 stores programs 976 for realizing each function of the in-vehicle device according to the first to fifth embodiments. The ROM958 stores the boot-up program for the MPU952, etc.

[0169] The MCU950 further includes a low-speed bus 960 connected to a high-speed bus 978 via a bridge 962, and a serial I / F 964, ADC 966, timer counter 968, clock generator 970, power control unit 972, and general-purpose I / F 974, all connected to the low-speed bus 960.

[0170] Since the operation of the MCU is well known, and what is meaningful in this embodiment is the functionality of the program it executes, the operation of the MCU itself will not be repeated in the following explanation.

[0171] B) Server hardware Figure 27 is an external view of an example of a computer system that implements the communication performance management servers 110 and 408, and the communication performance management server 658, etc., according to the above embodiment. Figure 28 is a block diagram showing an example of the hardware configuration of the computer system shown in Figure 27.

[0172] Referring to Figure 27, this computer system 1050 includes a computer 1070 to which a DVD drive 1102 is connected, and a keyboard 1074, a mouse 1076, and a monitor 1072, all connected to the computer 1070, for user interaction. These are just one example of a configuration for when user interaction is required, and any general hardware and software available for user interaction (e.g., touch panels, voice input, pointing devices in general) can be used.

[0173] Referring to Figure 28, the computer 1070 includes a CPU 1090, a GPU 1092, a bus 1110 connected to the CPU 1090, GPU 1092, and DVD drive 1102, a ROM 1096 connected to the bus 1110 and storing the computer 1070's boot-up program, etc., a RAM 1098 connected to the bus 1110 and storing program instructions, system programs, and work data, etc., and an SSD 1100, which is a non-volatile memory connected to the bus 1110. The SSD 1100 stores programs executed by the CPU 1090 and GPU 1092, as well as data used by programs executed by the CPU 1090 and GPU 1092. The computer 1070 further includes a network interface 1108 that provides a connection to a network 1086 that enables communication with other terminals, and a USB port 1106 that allows a USB memory stick 1084 to be inserted and removed and provides communication between the USB memory stick 1084 and various parts within the computer 1070.

[0174] Computer 1070 further includes an input / output interface 1104 connected to bus 1110 with external devices such as microphone 1082 and speaker 1080, which read audio signals, video signals, and text data generated by CPU 1090 and stored in RAM 1098 or SSD 1100 according to instructions from CPU 1090, perform analog conversion and amplification processing to drive speaker 1080, and digitize the analog audio signal from microphone 1082 and store it in RAM 1098 or SSD 1100 at any address specified by CPU 1090.

[0175] In each of the above embodiments, the programs, parameters, and sample images used in the fifth embodiment for implementing the communication performance management servers 110, 408, and 658 are all stored in storage media of external devices (not shown) connected via network I / F 1108 and network 1086, such as the SSD 1100, RAM 1098, DVD 1078, or USB memory 1084 shown in Figure 28. Typically, this data and parameters are written to the SSD 1100 from an external source and loaded into the RAM 1098 when executed by the computer 1070.

[0176] A program that implements the functions of each part according to the above embodiment in cooperation with computer 1070 includes a plurality of instructions written and arranged to operate computer 1070 to implement those functions. Some of the basic functions necessary to execute these instructions are provided by an operating system (OS) running on computer 1070, a third-party program, or modules of various toolkits installed on computer 1070. Therefore, this program does not necessarily have to include all the functions necessary to implement the system and method of this embodiment. This program only needs to include instructions that perform the operation of each of the above-described devices and their components by statically linking appropriate functions or functions of the "programming toolkit" in a controlled manner to obtain the desired result, or by dynamically linking to those functions during program execution. The method of operating computer 1070 for this purpose is well known and will not be repeated here.

[0177] Furthermore, the GPU 1092 is capable of parallel processing, and can perform large amounts of calculations, such as those associated with pathfinding and statistical processing, concurrently in parallel or via pipeline. For example, parallel computation elements discovered in the program during compilation or during program execution are dispatched from the CPU 1090 to the GPU 1092 as needed, executed, and the results are returned to the CPU 1090 either directly or via a predetermined address in RAM 1098 and assigned to a predetermined variable in the program.

[0178] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of this disclosure is not defined by the description in the detailed description of the disclosure but by the claims, and all modifications within the meaning and scope equivalent to the wording of the claims are intended. [Explanation of symbols]

[0179] 50 Route suggestion screen 60 vehicles 62 Current location 64 Destination 66. Route 1 68 Second Route 100, 400, 500 Vehicle Assistance Systems 102, 104, 106, 402, 404, 406, 502, 504, 506, 652, 654, 656 On-board equipment 108 servers 110, 408, 658 Communication performance management server 112 sensors 114 GNSS receiver 116 Touch panel display device 150, 550 Communications Department 152 CAN 154 Communication Records Department 156 Communication Performance Information Database 158, 204, 554, 724 Communication Record Transmission Unit 160, 200, 450 Communication Record Acquisition Department 162 Driver's Unit 164, 452, 556, 704 Route calculation unit 166 Grid drawing section 202 Communication performance information storage unit 552 Communication Performance Comparison Department 650 Driver Assistance Systems 700, 720 Communications Statistics Calculation Department 702 Communication Performance Statistics Database 722 Communication performance statistics information storage unit 800 display 810 Route display 812 First Route Prediction Image Display 814 Second Route Prediction Image Display 816 Vehicle Images 820, 822, 824, 826 speech bubbles 830 Route 950 MCU 952 MPU 954 SRAM 956 Flash Memory 958, 1096 ROM 960 Slow Bus 962 Bridge 964 Serial I / F 966 ADC 968 Timer Counter 970 Clock Generator 972 Power Control Unit 974 General-purpose I / F 976 Programs 978 Express Bus 1050 Computer System 1070 Computer 1072 monitors 1074 keyboard 1076 mice 1078 DVD 1080 Speakers 1082 Microphone 1084 USB flash drives 1086 Network 1090 CPU 1092 GPU 1098 RAM 1100 SSD 1102 DVD drive 1104 Input / Output Interface 1106 USB ports 1108 Network I / F 1110 Bus

Claims

1. A communication performance information receiving unit for receiving communication performance information which includes at least location information, date and time information, and communication quality metrics information relating at least to the communication quality of wireless communication at the location specified by the location information and at the date and time specified by the date and time information, A communication performance information storage unit for storing the communication performance information received by the communication performance information receiving unit, A communication record transmission unit, in response to receiving a request from an external device to transmit the communication record information with a specified geographical range, generates communication record information, including location information corresponding to the geographical range specified by the transmission request and communication quality information obtained from the communication quality metrics information, based on the communication record information stored in the communication record information storage unit, and transmits it to the external device. A communication statistics calculation unit calculates communication performance statistics by performing statistical processing on the communication performance information stored in the communication performance information storage unit, with respect to at least the location identified by the location information as the basis for the communication performance statistics; The system includes a communication performance statistics information storage unit that stores the communication performance statistics information calculated by the communication statistics calculation unit in association with the location information, The communication performance transmission unit includes a communication performance statistics information transmission unit that, in response to receiving a transmission request for the communication performance information with a specified geographical range from the external device, transmits to the external device the location information corresponding to the geographical range specified by the transmission request and the communication performance statistics information at the location identified by the location information, from among the communication performance statistics information stored in the communication performance statistics information storage unit. The communication statistics calculation unit includes a period-specific communication statistics calculation unit that performs statistical processing on the communication performance information stored in the communication performance information storage unit, based on at least the location specified by the location information and the period specified by the date and time information, to calculate period-specific communication performance statistics. Each of the aforementioned communication performance information further includes information about the communication environment at the time the wireless communication related to the communication performance information was performed, The aforementioned transmission request may include information regarding the communication environment of the external device. The communication record transmission unit selectively performs a first process and a second process depending on whether the received transmission request includes the information relating to the communication environment. The first process involves reading the communication performance statistics information from the communication performance statistics information storage unit, the location information corresponding to the geographical range specified by the transmission request, and the information relating to the communication environment included in the transmission request, calculating the communication quality metrics information based on the read communication performance statistics information, and transmitting it to the external device. The second process described above is a communication record management server, which reads the communication record information corresponding to the location information within the geographical range specified by the transmission request from the communication record information storage unit and transmits it to the external device.

2. The communication performance management server according to claim 1, wherein the information relating to the communication environment includes communication line information, communication carrier information, or a combination thereof.

3. A computer receives communication history information which includes at least location information, date and time information, and communication quality metrics information relating at least to the communication quality of wireless communication at the location specified by the location information and at the date and time specified by the date and time information. The computer includes the step of receiving the communication record information, and the step of storing the received communication record information in a storage device, A communication record transmission step in which a computer, in response to receiving a request from an external device to transmit the communication record information with a specified geographical range, generates communication record information including location information corresponding to the geographical range specified by the transmission request and communication quality information obtained from the communication quality metrics information, based on the communication record information stored in the storage device, and transmits it to the external device; A communication statistics calculation step in which a computer performs statistical processing on the communication performance information stored in the storage device, using at least the location identified by the location information as a reference, to calculate communication performance statistics information, The computer includes the step of storing the communication performance statistics information calculated in the communication statistics calculation step in a communication performance statistics information storage device in association with the location information, The communication performance transmission step includes a communication performance statistics information transmission step in which, in response to the computer receiving the transmission request for the communication performance information with a specified geographical range from the external device, the computer transmits to the external device the location information corresponding to the geographical range specified by the transmission request and the communication performance statistics information at the location identified by the location information, from among the communication performance statistics information stored in the communication performance statistics information storage device. The communication statistics calculation step includes a period-specific communication statistics calculation step in which a computer performs statistical processing on the communication performance information stored in the storage device, based on at least the location specified by the location information and the period specified by the date and time information, to calculate period-specific communication performance statistics. Each of the aforementioned communication performance information further includes information about the communication environment at the time the wireless communication related to the communication performance information was performed, The aforementioned transmission request may include information regarding the communication environment of the external device. In the communication record transmission step, the computer selectively performs the first process and the second process depending on whether the received transmission request includes the information relating to the communication environment. The first process involves reading the communication performance statistics information from the communication performance statistics information storage device, the location information corresponding to the geographical range specified by the transmission request, and the information relating to the communication environment included in the transmission request, calculating the communication quality metrics information based on the read communication performance statistics information, and transmitting it to the external device. The second process is a communication record management method, which involves reading the communication record information corresponding to the location information within the geographical range specified by the transmission request from the storage device and transmitting it to the external device.

4. On the computer, A step of receiving communication performance information which includes at least location information, date and time information, and communication quality metrics information relating at least to the communication quality of wireless communication at the location specified by the location information and at the date and time specified by the date and time information; The step of receiving the communication performance information includes storing the received communication performance information in a storage device, A communication record transmission step in which, in response to receiving a request from an external device to transmit the communication record information with a specified geographical range, the device generates communication record information, including location information corresponding to the geographical range specified by the transmission request and communication quality information obtained from the communication quality metrics information, based on the communication record information stored in the storage device, and transmits it to the external device; A communication statistics calculation step involves performing statistical processing on the communication performance information stored in the storage device, using at least the location identified by the location information as a reference, to calculate communication performance statistics; A computer program that causes a computer program to perform the steps of storing the communication performance statistics information calculated in the communication statistics calculation step in a communication performance statistics information storage device in association with the location information, The communication performance transmission step includes, in response to receiving a transmission request for communication performance information with a specified geographical range from the external device, a communication performance statistics information transmission step that transmits to the external device the location information corresponding to the geographical range specified by the transmission request and the communication performance statistics information at the location identified by the location information, from among the communication performance statistics information stored in the communication performance statistics information storage device. The communication statistics calculation step includes a period-specific communication statistics calculation step that performs statistical processing on the communication performance information stored in the storage device, based on at least the location specified by the location information and the period specified by the date and time information, to calculate period-specific communication performance statistics, Each of the aforementioned communication performance information further includes information about the communication environment at the time the wireless communication related to the communication performance information was performed, The aforementioned transmission request may include information regarding the communication environment of the external device. The communication record transmission step selectively performs a first process and a second process depending on whether the received transmission request includes the information relating to the communication environment. The first process involves reading the communication performance statistics information from the communication performance statistics information storage device, the location information corresponding to the geographical range specified by the transmission request, and the information relating to the communication environment included in the transmission request, calculating the communication quality metrics information based on the read communication performance statistics information, and transmitting it to the external device. The second process described above is a computer program that reads the communication record information corresponding to the location information within the geographical range specified by the transmission request from the storage device and transmits it to the external device.

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