Driving assistance system, in-vehicle device, driving assistance server, driving assistance method, computer program, and storage medium

Abstract

To make it easy to determine a travel route that ensures continuous acquisition of sufficient communication quality.SOLUTION: A driving assistance system includes: a communication actual result map information storage unit that stores a map related to a predetermined area and actual result information regarding communication quality within the area; a route calculation unit that, in response to a vehicle's destination being specified, calculates multiple travel routes of the vehicle from the vehicle's current location to the destination based on the communication quality required by services available using a communication device and the information stored in the communication actual result information storage unit; and a route display unit that displays the multiple travel routes calculated by the route calculation unit on a display device.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a driving assistance system, an in-vehicle device, a driving assistance server, a driving assistance method, a computer program, and a storage medium. [Background technology]

[0002] An increasing number of in-vehicle devices are equipped with the functionality to receive various services from external servers via wireless communication and to transmit information acquired by in-vehicle sensors to external servers. Vehicles equipped with such in-vehicle devices are called connected cars.

[0003] When a connected car uses a service that requires wireless communication, communication quality becomes an issue. If communication quality deteriorates or the car is out of range, the service cannot be used.

[0004] One proposal to solve these problems is disclosed in Patent Document 1, which will be described later. The technology disclosed in Patent Document 1 aims to visually notify the communication environment. The technology disclosed in Patent Document 1 acquires a field strength map showing a predetermined field strength, and displays the field strength map superimposed on a graphic showing the vehicle's traveling position based on road map data and the vehicle position. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-135099 Summary of the Invention [Problem to be solved by the invention]

[0006] For connected cars to receive adequate service, it is not just the electric field strength that is important. With the increasing number of on-board sensors and the volume of data, communication speed is also important when connected cars send sensor data to external servers and download data for driving assistance from external servers. In addition to these, latency is also important when communicating data related to vehicle safety.

[0007] The technology disclosed in Patent Document 1 displays a field strength map superimposed on a map. It is clear that communication speeds decrease in areas with low field strength. However, high field strength does not necessarily mean high communication speeds. Depending on the situation, high field strength may result in decreased communication speeds or increased latency. Even slight changes in the environment may cause a sudden deterioration in communication speed. The vehicle's position and surrounding conditions change constantly. Therefore, even if a field strength map is obtained, it is difficult to predict how communication speeds, latency, etc. will actually change, and it is not necessarily possible to obtain communication quality sufficient for using services while the connected car is traveling. In other words, the technology disclosed in Patent Document 1 is not considered sufficient for application to connected cars.

[0008] Therefore, an object of this disclosure is to provide a driving assistance system, an in-vehicle device, a driving assistance server, a driving assistance method, a computer program, and a storage medium that can easily determine a driving route that will continuously provide sufficient communication quality. [Means for solving the problem]

[0009] A driving assistance system according to a first aspect of the present disclosure includes a communication history map information storage unit for storing a map relating to a predetermined area and history information relating to communication quality within the area, a route calculation unit for calculating, in response to a destination of the vehicle being specified, a plurality of driving routes for the vehicle from the current position of the vehicle to the destination based on the communication quality required for a service available using a communication device and the information stored in the communication history map information storage unit, and a route display unit for displaying the plurality of driving routes calculated by the route calculation unit on a display device.

[0010] A driving assistance system according to a second aspect of the present disclosure is a driving assistance system including an in-vehicle device equipped with a communication device and a server for providing driving assistance to a vehicle equipped with the in-vehicle device, wherein the in-vehicle device includes a position information acquisition unit for acquiring position information of the vehicle equipped with the communication device, a communication performance map information storage unit for saving a map related to a predetermined area and performance information related to communication quality in the area, and an information transmission unit for measuring communication quality by the communication device and transmitting communication performance information to the server, the communication performance information including the measured communication quality, position information acquired by the position information acquisition unit when the communication quality was measured, and measurement time information specifying when the communication quality was measured, and the server acquires communication performance information from a plurality of in-vehicle devices. The communication performance information acquisition unit includes a communication performance map information storage unit that stores communication performance information acquired by the communication performance information acquisition unit, and a communication performance distribution unit that distributes the communication performance information stored in the communication performance map information storage unit to a plurality of in-vehicle devices. The in-vehicle device further includes a communication performance information addition unit that adds the communication performance information distributed by the server to the communication performance map information storage unit, a route calculation unit that calculates a plurality of driving routes for the vehicle from the current position of the vehicle to the destination based on the communication quality required for services available using the communication device and the information stored in the communication performance map information storage unit in response to a request to calculate a planned driving route by specifying a destination of the vehicle, and a route display unit that displays the plurality of driving routes calculated by the route calculation unit.

[0011] an information transmitting unit that measures communication quality by the communication device and transmits communication performance information to the server, the communication performance information including the measured communication quality, the location information acquired by the location information acquiring unit when the communication quality was measured, and measurement time information that identifies the time when the communication quality was measured; a communication performance map information adding unit that acquires communication performance information regarding communication quality in the area collected by multiple in-vehicle devices from the server and adds and stores the information in the communication performance map information storing unit; a route calculation unit that, in response to a destination of the vehicle being specified, calculates multiple driving routes for the vehicle from the current location of the vehicle to the destination based on the communication quality required for a service available using the communication device and the information stored in the communication performance map information storing unit; and a route display unit that displays the multiple driving routes calculated by the route calculation unit.

[0012] A driving assistance server according to a fourth aspect of the present disclosure includes: a communication performance information storage unit that receives and stores communication performance information from a plurality of on-board devices, the communication performance information including communication quality measured by each on-board device, location information indicating the location of each on-board device at the time the communication quality was measured, and measurement time information specifying the time when the communication quality was measured; and a communication performance distribution unit that distributes the communication performance information stored in the communication performance information storage unit to each of the plurality of on-board devices according to a predetermined schedule.

[0013] A driving assistance method according to a fifth aspect of this disclosure includes the steps of: a computer storing a map relating to a predetermined area and historical information relating to communication quality in the area in a storage device; a computer calculating, in response to a destination of the vehicle being specified, a plurality of driving routes for the vehicle from the current position of the vehicle to the destination based on the communication quality required by available services using a communication device and the information stored in the storage device; and a computer displaying, on a display device, the plurality of driving routes calculated in the route calculation step.

[0014] A computer program according to a sixth aspect of the present disclosure causes a computer to function to execute the driving assistance method.

[0015] A computer program according to a seventh aspect of the disclosure causes a computer to function as: a location information acquisition device for acquiring location information of a vehicle equipped with a communication device; a communication history map information storage unit for storing a map of an area passable by the vehicle and history information on communication quality in the area; an information transmission unit that measures communication quality by the communication device and transmits communication history information to a server, the communication history information including the measured communication quality, location information acquired by the location information acquisition device when the communication quality was measured, and measurement time information that identifies the time when the communication quality was measured; a communication history map information addition unit that acquires communication history information on communication quality in the area collected by multiple in-vehicle devices from the server and adds and stores the information in the communication history map information storage unit; a route calculation unit that, in response to a destination of the vehicle being specified, calculates multiple driving routes for the vehicle from the current location of the vehicle to the destination based on the communication quality required for services available using the communication device and the information stored in the communication history map information storage unit; and a route display device that displays the multiple driving routes calculated by the route calculation unit.

[0016] The above and other objects, features, aspects and advantages of the present disclosure will become apparent from the following detailed description of the disclosure taken in conjunction with the accompanying drawings. [Effects of the Invention]

[0017] As described above, this disclosure makes it possible to provide a driving assistance system, an in-vehicle device, a driving assistance server, a driving assistance method, a computer program, and a storage medium that can continuously obtain sufficient communication quality. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a diagram showing a route proposal screen on the vehicle-mounted device according to the first embodiment. [Figure 2] FIG. 2 is a block diagram showing the overall configuration of the vehicle assistance system according to the first embodiment. [Figure 3] FIG. 3 is a block diagram showing the configuration of the vehicle-mounted device according to the first embodiment. [Figure 4] FIG. 4 is a block diagram showing the configuration of the communication record management server according to the first embodiment. [Figure 5] FIG. 5 is a block diagram showing the record configuration of a communication history map information DB (Database) according to the first embodiment. [Figure 6] FIG. 6 is a flowchart showing a control structure of a computer program realizing the communication performance recording unit according to the first embodiment. [Figure 7] FIG. 7 is a flowchart showing a control structure of a computer program that realizes the driving section according to the first embodiment. [Figure 8] FIG. 8 is a flowchart showing a control structure of a computer program implementing the path calculation unit according to the first embodiment. [Figure 9] FIG. 9 is a flowchart showing a control structure of a computer program implementing the grid drawing unit according to the first embodiment. [Figure 10] FIG. 10 is a block diagram showing the configuration of a vehicle assistance system according to the second embodiment. [Figure 11] FIG. 11 is a block diagram showing the configuration of the vehicle-mounted device according to the second embodiment. [Figure 12] FIG. 12 is a block diagram showing the configuration of a communication record management server according to the second embodiment. [Figure 13] FIG. 13 is a block diagram showing the configuration of a vehicle assistance system according to the second embodiment. [Figure 14] FIG. 14 is a flowchart showing a control structure of a computer program realizing the vehicle-mounted device according to the second embodiment. [Figure 15] FIG. 15 is a block diagram showing the configuration of a communication performance comparison unit according to the second embodiment. [Figure 16]FIG. 16 is a block diagram showing the configuration of a driving assistance system according to the third embodiment. [Figure 17] FIG. 17 is a block diagram showing the configuration of the vehicle-mounted device according to the third embodiment. [Figure 18] FIG. 18 is a block diagram showing the configuration of a communication record management server according to the third embodiment. [Figure 19] FIG. 19 is a diagram showing the record configuration of the communication performance statistical information DB according to the third embodiment. [Figure 20] FIG. 20 is a diagram showing a display in the vehicle assistance system according to the fourth embodiment. [Figure 21] FIG. 21 is a flowchart showing a control structure of a computer program for generating a display in the vehicle assistance system in accordance with the fourth embodiment. [Figure 22] FIG. 22 is a flowchart showing a control structure of a computer program for displaying a driving route. [Figure 23] FIG. 23 is a block diagram showing a configuration of steps for realizing the vehicle-mounted device of each embodiment according to this disclosure. [Figure 24] FIG. 24 is a diagram showing the appearance of a computer system that realizes each driving assistance server according to this disclosure. [Figure 25] FIG. 25 is a hardware configuration diagram of the computer system shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0019] [Description of the embodiments of the present disclosure] In the following description and drawings, the same parts are designated by the same reference numerals, and therefore detailed description thereof will not be repeated.

[0020] The main embodiments shown in this disclosure are listed below. Note that one or more of the following embodiments may be arbitrarily combined.

[0021] (1) A driving assistance system according to a first aspect of this disclosure includes a communication history map information storage unit for storing a map of a predetermined area and history information on communication quality within the area; a route calculation unit that, in response to a destination of the vehicle being designated, calculates a plurality of driving routes for the vehicle from the current position of the vehicle to the destination based on the communication quality required for a service available using a communication device and the information stored in the communication history map information storage unit; and a route display unit that displays the plurality of driving routes calculated by the route calculation unit on a display device.

[0022] A driving route is calculated and displayed based on performance information regarding communication quality, making it easy to determine a driving route that will ensure sufficient communication quality on an ongoing basis.

[0023] (2) In (1) above, the route display unit may divide the area, at least the portion through which the multiple driving routes calculated by the route calculation unit pass, into multiple grid areas, and display the grid areas with different attributes depending on the communication quality in each of the grid areas, superimposed on the display by the route display unit.

[0024] The driving route is calculated based on performance information on communication quality, and the grid area including the driving route is displayed with attributes corresponding to the communication quality. As a result, it is easy to determine a driving route that will continuously provide sufficient communication quality.

[0025] (3) In (2) above, the route display unit may vary the hue, brightness, or saturation of each of the plurality of grid areas as a monotonic function of the communication quality value in that grid area, and display the result superimposed on the display by the route display unit.

[0026] The driving route is calculated based on actual information about communication quality, and the surrounding grid area is displayed as a monotonic function of communication quality, making it easy to determine a driving route that will consistently provide sufficient communication quality.

[0027] (4) In (1) above, the route display unit may display each of the multiple travel routes calculated by the route calculation unit and the communication quality available on the travel route in association with each of the multiple travel routes.

[0028] As a result, it is easy to determine a driving route that will ensure sufficient communication quality continuously.

[0029] (5) In the above (1), the driving assistance system may further include a representative value calculation unit for calculating a statistical representative value of the communication quality available for each of the multiple driving routes based on the performance information stored in the communication performance map information storage unit, and a representative value display unit for displaying the statistical representative value calculated for the multiple driving routes by the representative value calculation unit superimposed on the display by the route display unit, and the route display unit may superimpose on the display by the display device a display that visually associates the statistical representative value displayed by the representative value display unit with a display corresponding to the statistical representative value among the displays of the multiple driving routes by the route display unit.

[0030] The driving route is calculated based on actual information on communication quality. Furthermore, a statistical representative value of communication quality is superimposed on the display of the driving route and displayed in association with the corresponding driving route. As a result, it is easy to determine a driving route that will consistently provide sufficient communication quality.

[0031] (6) In (5) above, the route display unit may superimpose a line connecting the statistical representative value displayed by the representative value display unit and a display corresponding to the statistical representative value among the multiple driving routes displayed by the route display unit on the display by the route display unit.

[0032] The statistical representative value of communication quality is superimposed on the display of the driving route and connected to the corresponding driving route by a line, making it easy to determine a driving route that will consistently provide sufficient communication quality.

[0033] (7) In (5) above, the related display unit may enclose the statistical representative value displayed by the representative value display unit and superimpose a speech bubble having a convex portion connected to the display corresponding to the statistical representative value among the multiple driving routes displayed by the route display unit on the display by the route display unit.

[0034] Statistical representative values ​​of communication quality are superimposed on the display of the driving route and displayed as balloons from the corresponding driving route, making it easy to determine a driving route that will consistently provide sufficient communication quality.

[0035] (8) In the above (1), the driving assistance system may further include a representative value calculation unit for calculating a statistical representative value of the communication quality available for each of the multiple driving routes based on the performance information stored in the communication performance map information storage unit, an image processing unit for generating a representative image from a predetermined sample image, the representative image being processed to an image quality corresponding to the statistical representative value calculated by the representative value calculation unit, and a representative image display unit for displaying on a display device the representative images generated by the image processing unit in association with the multiple driving routes displayed by the route display unit.

[0036] The image quality is processed based on the communication quality and displayed by the representative image display unit. The user can concretely experience the communication quality of each driving route in the form of the image quality of the sample image. As a result, it is easy to determine a driving route that will continuously provide sufficient communication quality.

[0037] (9) In any one of (1) to (8) above, the route calculation unit may include a communication quality constraint unit that determines multiple different constraints regarding the communication quality that the multiple driving routes must satisfy, based on the communication quality required by services available using the communication device, and a multiple route calculation unit that, in response to a destination of the vehicle being specified, calculates multiple driving routes that satisfy each of the multiple constraints determined by the communication quality constraint unit and that have the shortest driving distance from the current position of the vehicle to the destination under the constraints, based on information stored in the communication history map information storage unit.

[0038] Under the constraints determined for communication quality, multiple driving routes that provide the shortest distance from the current location to the destination are calculated and displayed. Since the shortest route under each constraint is displayed, the user can easily determine a driving route that will allow them to continuously obtain a certain level of communication quality and arrive at the destination as quickly as possible, based on the constraints for communication quality and the time required to reach the destination.

[0039] (10) In (9) above, the multiple constraints may include at least the constraint that communication quality is not restricted, that communication quality is at least a predetermined quality throughout the driving route, or that communication quality is at least a first quality sufficient to use a predetermined first service in a first portion of the driving route, and at least a second quality sufficient to use a second service that is lower than the first quality but substitutes for the predetermined first service in a second portion.

[0040] The system calculates and displays multiple routes that provide the shortest distance from the current location to the destination, based on at least one of these constraints. This makes it easy to determine a route that allows the user to reach the destination as quickly as possible while still maintaining the communication quality determined by these constraints.

[0041] (11) In any one of (1) to (10) above, the driving assistance system may further include a location information acquisition device for acquiring location information of a vehicle equipped with a communication device, and a communication performance update unit for collecting the communication quality performance of the communication device while the vehicle is traveling on one of a plurality of driving routes, and updating the performance information stored in the communication performance map information storage unit using the communication quality.

[0042] The performance information stored in the communication performance map information storage unit is updated based on performance information regarding communication quality while the vehicle is traveling. As a result, when calculating subsequent routes, it is possible to more reliably determine a driving route that will continue to provide sufficient communication quality.

[0043] (12) In the above (11), the driving assistance system may further include a route calculation re-execution unit that causes the route calculation unit to re-execute route calculation in response to a difference between the actual communication quality collected by the communication history update unit for the driving route on which the vehicle is traveling and the communication quality predicted for the driving route based on the communication history map information storage unit being equal to or greater than a threshold value.

[0044] Based on the performance information on the communication quality while the vehicle is traveling, the performance information stored in the communication performance map information storage unit is updated, and the route calculation is then re-executed. As a result, the travel route is changed so that appropriate communication quality can be continuously obtained according to the actual communication quality while the vehicle is traveling.

[0045] (13) In any one of (1) to (12) above, the driving assistance system may further include a statistical quantity calculation unit that calculates statistical quantities for each unit time for each of the plurality of grid areas based on performance information stored in the communication performance map information storage unit, and the communication performance map information storage unit may further store statistical quantities in addition to the performance information, and the route calculation unit may include a statistical route calculation unit that, in response to a destination of the vehicle being specified, calculates a plurality of driving routes for the vehicle from the current position of the vehicle to the destination based on the communication quality required for services available using the communication device and the statistical quantities stored in the communication performance map information storage unit.

[0046] The driving route is calculated based on statistical information on communication quality while the vehicle is traveling. The driving route calculation process is shortened, and the communication bandwidth used for data communication is also reduced. As a result, a driving route can be determined that continuously ensures sufficient communication quality using fewer computational or communication resources.

[0047] (14) In (1) above, the route display unit may include a communication quality-based route display unit that displays each portion of a plurality of driving routes with different display attributes depending on the communication quality in the grid area that overlaps with the portion.

[0048] Each section of the route is displayed with different display attributes depending on the communication quality at that location. As a result, the state of communication quality at each section of the route can be easily understood, and a route that will ensure sufficient communication quality can be easily selected.

[0049] (15) In (14) above, the display attributes may include hue, brightness, or saturation of each portion of the multiple travel routes.

[0050] The user can easily understand the state of communication quality on each driving route based on the difference in hue, brightness or saturation, and can easily select a driving route that will allow sufficient communication quality to be continuously obtained.

[0051] (16) In (15) above, the brightness or saturation is set to be high if the communication quality is good, and low if the communication quality is poor.

[0052] The state of communication quality on each driving route can be easily understood, and a driving route that will continuously provide sufficient communication quality can be easily selected.

[0053] (17) In the above (15) or (16), the hue is red.

[0054] The state of communication quality on each driving route can be intuitively understood, and a driving route that will continuously provide sufficient communication quality can be easily selected.

[0055] (18) In any one of (1) to (17) above, the driving assistance system may further include a communication history storage unit that acquires performance information regarding communication quality in each of a plurality of grid areas from a plurality of on-board devices and stores the information in a communication history map information storage unit.

[0056] By receiving and storing communication records from a plurality of vehicle-mounted devices, the number of communication records in many areas can be increased, and a driving route that ensures sufficient communication quality can be determined with higher reliability.

[0057] (19) A driving assistance system according to a second aspect of the present disclosure includes an on-board device equipped with a communication device and a server for providing driving assistance to a vehicle equipped with the on-board device, wherein the on-board device includes a location information acquisition unit for acquiring location information of the vehicle equipped with the communication device, a communication history map information storage unit for storing a map related to a predetermined area and history information related to communication quality in the area, and an information transmission unit for measuring communication quality by the communication device and transmitting communication history information to the server, the communication history information including the measured communication quality, location information acquired by the location information acquisition unit at the time of measuring the communication quality, and measurement time information specifying the time of measuring the communication quality, and the server receives communication history information from a plurality of on-board devices. The vehicle-mounted device includes an information acquisition unit, a communication history map information storage unit that stores communication history information acquired by the communication history information acquisition unit, and a communication history distribution unit that distributes the communication history information stored in the communication history map information storage unit to a plurality of vehicle-mounted devices. The vehicle-mounted device further includes a communication history information addition unit that adds the communication history information distributed by the server to the communication history map information storage unit, a route calculation unit that calculates a plurality of vehicle driving routes from the current position of the vehicle to the destination based on the communication quality required for services available using the communication device and the information stored in the communication history map information storage unit in response to a request to calculate a planned driving route by specifying a destination of the vehicle, and a route display unit that displays the plurality of driving routes calculated by the route calculation unit.

[0058] The server accumulates performance information received from multiple in-vehicle devices and transmits it to the in-vehicle devices. Based on this performance information, the in-vehicle devices calculate and display a driving route. As a result, it is possible to easily and reliably determine a driving route that will continuously provide sufficient communication quality.

[0059] (20) An in-vehicle device according to a third aspect of this disclosure is an in-vehicle device that provides driving assistance for a vehicle by communicating with a predetermined driving assistance server, and includes: a location information acquisition unit for acquiring location information of a vehicle equipped with a communication device; a communication history map information storage unit for storing a map related to a predetermined area and history information related to communication quality in the area; an information transmission unit that measures communication quality by the communication device and transmits communication history information to the server, the communication history information including the measured communication quality, location information acquired by the location information acquisition unit when the communication quality was measured, and measurement time information that identifies the time when the communication quality was measured; a communication history map information addition unit that acquires communication history information related to communication quality in the area collected by multiple in-vehicle devices from the server and adds and stores the information in the communication history map information storage unit; a route calculation unit that, in response to a destination of the vehicle being specified, calculates multiple driving routes for the vehicle from the current location of the vehicle to the destination based on the communication quality required for a service available using the communication device and the information stored in the communication history map information storage unit; and a route display unit that displays the multiple driving routes calculated by the route calculation unit.

[0060] The in-vehicle device calculates and displays a route based on not only the performance information on communication quality accumulated by each in-vehicle device but also the performance information received by the server from multiple in-vehicle devices. As a result, it is possible to easily and reliably determine a route that will continuously provide sufficient communication quality.

[0061] (21) A driving assistance server according to a fourth aspect of this disclosure includes: a communication performance information storage unit that receives and stores communication performance information from a plurality of on-board devices, the communication performance information including communication performance related to communication quality measured by each on-board device, location information indicating the location of each on-board device at the time the communication performance was measured, and measurement time information specifying the time when the communication quality was measured; and a communication performance distribution unit that distributes the communication performance information stored in the communication performance information storage unit to each of the plurality of on-board devices according to a predetermined schedule.

[0062] The driving assistance server receives and stores communication records from multiple in-vehicle devices. The stored communication records are then transmitted to the multiple in-vehicle devices. Each in-vehicle device can use the communication records from multiple areas to more reliably determine a driving route that will ensure sufficient communication quality over a wider area.

[0063] (22) A driving assistance method according to a fifth aspect of this disclosure includes the steps of: a computer storing a map relating to a predetermined area and historical information relating to communication quality in the area in a storage device; a computer calculating, in response to a destination of the vehicle being specified, a plurality of driving routes for the vehicle from the current position of the vehicle to the destination based on the communication quality required by available services using a communication device and the information stored in the storage device; and a computer displaying, on a display device, the plurality of driving routes calculated in the route calculation step.

[0064] A driving route is calculated and displayed based on performance information regarding communication quality, making it easy to determine a driving route that will ensure sufficient communication quality on an ongoing basis.

[0065] (23) A computer program according to a sixth aspect of the present disclosure causes a computer to function to execute the driving assistance method.

[0066] A driving route is calculated and displayed based on performance information regarding communication quality, making it easy to determine a driving route that will ensure sufficient communication quality on an ongoing basis.

[0067] (24) A computer program according to a seventh aspect of this disclosure causes a computer to function as: a location information acquisition device for acquiring location information of a vehicle equipped with a communication device; a communication history map information storage unit for storing a map of an area passable by the vehicle and history information on communication quality in the area; an information transmission unit that measures communication quality by the communication device and transmits communication history information to a server, the communication history information including the measured communication quality, location information acquired by the location information acquisition device when the communication quality was measured, and measurement time information that identifies the time when the communication quality was measured; a communication history map information addition unit that acquires communication history information on communication quality in the area collected by multiple in-vehicle devices from the server and adds and stores the information in the communication history map information storage unit; a route calculation unit that, in response to a destination of the vehicle being specified, calculates multiple driving routes for the vehicle from the current location of the vehicle to the destination based on the communication quality required for a service available using the communication device and the information stored in the communication history map information storage unit; and a route display device that displays the multiple driving routes calculated by the route calculation unit.

[0068] The computer calculates and displays a route based on not only the performance information regarding communication quality accumulated by each computer but also the performance information accumulated by the server from multiple in-vehicle devices, making it easier and more reliable to determine a route that will consistently provide sufficient communication quality.

[0069] [Details of the embodiments of the present disclosure] Specific examples of route suggestion screens according to embodiments of the present disclosure will be described below with reference to the drawings. Note that the present disclosure is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0070] 1. First embodiment A.Configuration A1) Route suggestion screen 50 Referring to FIG. 1 , a route proposal screen 50 in the vehicle assistance system according to the first embodiment is used to propose to a user a first route 66 and a second route 68 from a current location 62 of a vehicle 60 to a destination 64, which are calculated under different constraints regarding communication quality along the route. The entire route proposal screen 50 is rectangular. Each rectangular area is divided into rectangular grids of equal 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 a map along with the first route 66 and the second route 68. Note that a map is not shown in FIG. 1 to simplify the drawing.

[0071] 1, grids with no hatching indicate that the communication quality is relatively good and is sufficient to receive the service to be used in the vehicle 60. Grids with no hatching indicate that the communication quality is worse and is insufficient to receive the service to be used in the vehicle 60. In this example, the hatched areas are displayed in red, and the unhatched areas are displayed transparently.

[0072] In FIG. 1, grids are classified into two types to facilitate understanding of the display related to communication quality. However, this disclosure is not limited to such an embodiment. Communication quality may be divided into three or more stages, and each stage may be displayed differently. Typically, grids with poor communication quality are displayed with a red hue and the lowest brightness. As communication quality improves, the brightness of the grid increases, and once the quality reaches a certain level, the grid is displayed colorless (transparent) or in a color other than red (for example, blue). Of course, various other methods for displaying grids are conceivable. The saturation may be changed without changing the brightness. Alternatively, both the hue and the brightness or saturation may be changed.

[0073] For example, it is usually sufficient to change the brightness in a positive correlation with the communication quality value. Conversely, in the case of saturation, it is possible to change it in a negative correlation with the communication quality value. In short, it is sufficient to make the display mode of each grid change as a monotonic function of the communication quality in that grid.

[0074] 1 further displays, as examples, a first route 66 and a second route 68. The first route 66 is calculated as a route by which the vehicle 60 travels from the current location 62 to the destination 64 in the shortest time without imposing any constraints on communication quality, for example. The second route 68 is also a route by which the vehicle 60 travels from the current location 62 to the destination 64, but is calculated as a route that provides the communication quality required to use a specific service in the vehicle 60, as a constraint on communication quality.

[0075] Constraints on communication quality are not limited to those listed here, and various other constraints can be set by the user of the vehicle 60.

[0076] A2) Vehicle assistance system 100 Referring to FIG. 2, the vehicle assistance system 100 according to the first embodiment of this disclosure includes a plurality of on-board devices 102, 104, and 106 each mounted on a separate vehicle, a server 108 for providing some kind of service to these on-board devices using communication, or conversely, receiving sensor data from the on-board devices and analyzing traffic conditions, and a communication history management server 110 for managing communication with a plurality of on-board devices such as the on-board device 102, accumulating information regarding actual communication quality in each grid of an area such as that shown in FIG. 1, and distributing the information to each on-board device.

[0077] The on-board device 102 and the like are mounted on a vehicle. Therefore, as will be described later, each of these devices has a wireless communication unit. A mobile phone line can be used as a wireless communication medium. It is also expected that Wi-Fi communication will be used in some locations. In any case, the on-board device 102 and the like can communicate with the server 108 and the communication history management server 110 via wireless communication with a base station and communication over a wired network from the base station to the server 108 and the communication history management server 110.

[0078] A3) Onboard equipment 102 3, the vehicle-mounted device 102 includes a communication unit 150 for communicating with an external device 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 controller area network (CAN) 152 connected to the sensor 112, a global navigation satellite system (GNSS) 114, and the communication history recording unit 154, and a communication history map information DB 156 connected to the communication history recording unit 154. The communication unit 150 further receives data for a service provided by the server 108 and transmits the data via the CAN 152 to a service execution unit such as an electronic control unit (ECU) (not shown).

[0079] The communication performance recording unit 154 periodically measures the communication quality during communication by the communication unit 150 and records the communication quality including the actual bit rate (communication speed). Even when communication by the communication unit 150 is not being performed, radio wave intensity information can be obtained, and therefore such information is recorded.

[0080] The communication history recording unit 154 receives sensor data from the GNSS 114 and various other sensors 112 mounted on the vehicle via the CAN 152, and records a record of communication history that combines vehicle status, location information, etc. obtained from this information in the communication history map information DB 156.

[0081] The vehicle-mounted device 102 further includes a communication history transmission unit 158 ​​connected to the communication history recording unit 154, a communication history acquisition unit 160 connected to the communication history map information DB 156, a driving unit 162 connected to the touch panel display device 116, a route calculation unit 164 connected to the communication history map information DB 156, the driving unit 162, and the communication history acquisition unit 160, and a grid drawing unit 166.

[0082] The communication history sending unit 158 ​​sends the communication history of the communication unit 150 recorded by the communication history recording unit 154 to the communication history management server 110 according to a predetermined transmission schedule. The communication history acquiring unit 160 acquires the communication history of other vehicles from the communication history management server 110 according to a predetermined schedule or when necessary, and updates (adds) the communication history map information DB 156. The driving unit 162 is a device for performing automatic driving or remote driving in addition to the functions of a general so-called in-vehicle navigation system, and receives input of information for route proposals (information regarding the destination of the driving route, etc.) through interaction with the user using the touch panel display device 116.

[0083] At this time, the driving unit 162 may allow the user to input constraints for generating the driving routes. For example, the constraints may include the number of driving routes to be generated, information identifying the services to be used on the driving routes, and conditions that the driving routes must satisfy. In the following embodiment, it is assumed that the user specifies that three driving routes be generated. The three routes are the shortest route connecting the current location and the destination regardless of the communication speed, the shortest route among driving routes that is expected to have a communication speed that allows the service to be used throughout, and a driving route that may not be able to use the service at a sufficient bit rate in some parts but is an alternative to the service if the communication speed is at least half of the specified bit rate, or a driving route that is the same as the service and is expected to ensure the required bit rate.

[0084] The route calculation unit 164 requests the communication history acquisition unit 160 to acquire information such as a location and time for which communication history is required from the communication history map information DB 156, based on the user input received by the driving unit 162 and the communication conditions required to use the service. The route calculation unit 164 calculates a plurality of driving routes under a plurality of types of constraints based on the communication history information acquired by the communication history acquisition unit 160 from the communication history map information DB 156, the destination information, and the required communication conditions, and displays the routes 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 history in each part of the displayed area, superimposed on the driving route candidates and map displayed on the touch panel display device 116. Note that the communication history information is a combination of the communication history and the vehicle's state at that time.

[0085] More specifically, the grid drawing unit 166 divides the displayed area into grids, adjusts the color, brightness, or saturation of each grid as a function of an index value representing the past communication performance (communication quality) of each grid, and displays the adjusted grid on the proposed driving route and the map. The past communication performance is obtained from information accumulated in the communication performance map information DB 156.

[0086] A4) Communication record management server 110 Referring to FIG. 4, the communication record management server 110 includes a communication record acquiring unit 200, a communication record map information storage unit 202, and a communication record transmitting unit 204.

[0087] The communication history acquiring unit 200 acquires communication history information collected by a plurality of in-vehicle devices at various locations and dates from the in-vehicle devices. The communication history map information storage unit 202 accumulates the communication history information received by the communication history acquiring unit 200. The communication history transmitting unit 204 transmits the communication history map information accumulated in the communication history map information storage unit 202 to in-vehicle devices (e.g., the in-vehicle devices 102, 104, and 106 shown in FIG. 2 ) of subscribers of the communication history management service provided by the communication history management server 110, according to a predetermined schedule.

[0088] A5) Configuration of communication record map information DB 156 5 shows an example of the column configuration of the table of the communication history map information DB 156. Referring to FIG. 5, the columns of the communication history map information DB 156 include a communication history ID and a vehicle ID. The communication history ID identifies a record of the communication history. The vehicle ID is an identifier that identifies the vehicle equipped with the on-board device that recorded the communication history.

[0089] Other columns include measurement interval, modem, GNSS (Global Navigation Satellite System), 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, (mobile phone) cell ID, SINR, RSSI, RSRP, and RSRQ.

[0090] The main features of these are: the measurement interval indicates the interval between measurements of the communication speed; the measurement interval is measured in seconds; the date and time indicates the date and time the communication record was acquired; the latitude and longitude indicate the location of the vehicle at the time of communication; the grid ID is the value obtained by converting the latitude and longitude into a string using a conversion method called geohash. A geohash is converted into a string by applying a specified conversion table to the latitude and longitude. Each string identifies a rectangular area on the ground. The longer the string, the smaller the rectangular area. If the first few digits of two strings match, the two rectangular areas identified by the two strings are within the rectangular area identified by the matching string. If the strings used as geohashes are the same length, the size (area) of the rectangular areas identified by them will be the same. Therefore, by setting the length of the strings used as geohashes to a fixed length and using the same first few characters, the map (and the corresponding area) can be divided into multiple adjacent rectangular areas. Here, such a rectangular area is called a grid, and its identifier (latitude and longitude converted into a geohash) is called a grid ID.

[0091] The communication speed indicates the communication speed measured for the actual communication if communication was possible at the time indicated by the value in the date and time column. If communication was not possible due to reasons such as being out of range, in this embodiment, "-1" is recorded as the communication speed.

[0092] SINR, RSSI, RSRP, and RSRQ respectively refer to the signal-to-interference-and-noise ratio, received signal strength, received power of the reference signal, and received quality of the reference signal, and correspond to the above-mentioned radio wave strength information.

[0093] In this way, the communication history map information DB 156 stores information indicating the communication quality including the communication speed measured in the actual communication together with the vehicle state at that time and the date and time. By this process, the communication history map information DB 156 is updated.

[0094] A6) Program control structure A6-1) Communication performance record section 154 The main parts of the vehicle-mounted device 102 shown in FIG. 3 are realized by a computer and a program executed by the computer.

[0095] Fig. 6 shows a control structure of a program that realizes communication performance recording unit 154 shown in Fig. 3. Referring to Fig. 6, this program includes step 250 that executes step 252 according to a predetermined schedule (at a fixed interval in this embodiment).

[0096] Step 252 includes step 260 of performing communication processing using communication unit 150 or measuring signal strength, step 262 of acquiring information indicating the vehicle status via CAN 152, and step 264 of combining the information acquired in steps 260 and 262 and recording the combined information in communication history map information DB 156.

[0097] This program further includes step 266, which branches the control flow depending on whether or not there is a communication history management server that cooperates with the vehicle-mounted device 102, and step 268, which, if the determination in step 266 is affirmative, sends communication history information to the cooperation communication history management server and terminates execution of step 252. If the determination in step 266 is negative, execution of step 252 is terminated.

[0098] A6-2) Path calculation unit 164 Fig. 7 shows a control structure of a program that realizes route calculation unit 164 shown in Fig. 3. Referring to Fig. 7, this program includes step 310 of acquiring the location of the destination through interaction with the user, and step 312 of acquiring information about the communication service required to receive the service from server 108 (information about the required communication speed, for example, bit rate, etc.).

[0099] This program further includes step 314 of acquiring communication history for an area including the vicinity of the current location to the vicinity of the destination from the communication history map information DB 156 (FIG. 3), step 316 of branching the control flow depending on whether or not there is a communication history management server linked to the vehicle-mounted device 102, and step 318 of branching the control flow depending on whether or not there is sufficient data from the communication history map information DB 156 for route calculation when the determination in step 316 is positive.

[0100] This program further includes step 320, in which, when the determination in step 318 is negative, the communication history of the area from the vicinity of the current location to the vicinity of the destination is acquired from a communication history management server (in this example, the communication history management server 110 shown in FIG. 2) linked to the in-vehicle device 102, and step 322, in which the acquired communication history is used to calculate a driving route, information about the calculated driving route is provided to the driving unit 162, and execution of the program is terminated. When the determination in step 316 is negative or when the determination in step 318 is positive, step 320 is not executed, and the route calculation process in step 322 is immediately executed.

[0101] 8 shows an example of the control structure of a program that realizes step 322 shown in FIG. 7. Referring to FIG. 8, step 322 includes step 350 of setting a search range for a travel route, and step 352 of generating a route graph that connects the current position and the destination within the search range based on map information provided in the driving unit 162. The route graph here refers to a graph in which intersections are nodes and roads connecting the intersections are edges (links). In this embodiment, each edge is assigned information indicating the length of the corresponding road. In this route graph, there are many routes that connect the current position and the destination.

[0102] This program further includes step 354 for searching for the shortest route from the current location to the destination in the route graph generated in step 352. In this embodiment, the Dijkstra algorithm is used to search for the shortest route. Of course, this is not limited to the Dijkstra algorithm, and any algorithm that can find the shortest route in a graph may be used.

[0103] This program further includes step 356 of referencing communication performance information and deleting from the route graph edges that include points where the bit rate is less than half the bit rate specified by the service; step 358 of searching for the shortest route in the route graph that has been processed in step 356; step 360 of deleting from the route graph links that include points where the bit rate is less than the specified bit rate; and step 362 of searching for the shortest route in the route graph that has been processed in step 360 and terminating step 322.

[0104] Through the above processing, it is possible to identify the shortest driving route regardless of the specified bit rate, the shortest driving route that can be driven at a bit rate at least half the specified bit rate, and the shortest driving route that can be driven at a bit rate equal to or higher than the specified bit rate.

[0105] 9 shows the control structure of a program that realizes the grid drawing unit 166 shown in FIG. 3. The grid diagram obtained by the grid drawing unit 166 is, for example, like the grid shown in FIG. 1. In FIG. 1, each grid is displayed in a different display mode depending on the communication speed available in that grid. The multiple driving routes generated in step 322 of FIG. 7 are displayed superimposed on a predetermined map, and a semi-transparent grid is further superimposed.

[0106] 9, this program includes step 370 of obtaining a geohash value representing an area displayed on touch panel display device 116 and dividing this area into a predetermined number of grid areas from the top left to the bottom right. Step 370 also calculates a geohash of a predetermined position (e.g., the center position) in each grid area.

[0107] The program further includes step 372 which performs step 374 for each grid region obtained in step 370 .

[0108] Step 374 includes step 380 of searching the communication history map information DB 156 for records that start with the same character string as the geohash of the grid area and whose date and time are within a predetermined range centered on the current time, and calculating the average communication speed of those records; and step 382 of quantizing the average communication speed calculated in step 380 into several stages and determining 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 function of 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 its maximum value when the communication speed is higher than a predetermined threshold.

[0109] Step 374 further includes step 384, in which the alpha value of each grid area when displayed is set to a value that represents semi-transparency, and step 374 is terminated. At this time, the alpha value is set so that the grid with the highest brightness is displayed transparently.

[0110] B. Operation B1) Accumulation of communication results While the vehicle equipped with the on-board device 102 is moving, the communication unit 150 periodically measures the communication speed. When communication is not being performed, the communication unit 150 measures the radio wave intensity. The communication unit 150 provides this information to the communication record recording unit 154 as communication record.

[0111] The communication history recording unit 154 receives information indicating the state of the vehicle from the sensor 112 and the GNSS 114 via the CAN 152. The communication history recording unit 154 generates communication history information from the communication history received from the communication unit 150 and information indicating the state of the vehicle, and stores the communication history information in a communication history map information DB 156.

[0112] B2) Enter your destination When the user sets off to a destination, the user interacts with the touch panel display device 116 to display an initial route setting screen and specify the destination and the service to be used. In step 310 of FIG. 7, the vehicle-mounted device 102 acquires the destination specification and identifies its location. In step 312, the route calculation unit 164 acquires information about the communication service required by the service specified by the user (step 312). As a result of this process, the required bit rate is determined.

[0113] The route calculation unit 164 further acquires communication history information relating to an area connecting the vicinity of the current location and the vicinity of the destination from the communication history map information DB 156 (step 314 in FIG. 7). If there is no communication history management server linked to the vehicle-mounted device 102 (the determination in step 316 in FIG. 7 is negative), the route calculation unit 164 executes a route calculation process (step 322 in FIG. 7). If there is a communication history management server linked to the vehicle-mounted device 102 (the determination in step 316 in FIG. 7 is positive), the route calculation unit 164 determines whether the communication history acquired from the communication history map information DB 156 is sufficient to determine a driving route based on a predetermined bit rate in the target area (step 318). If the determination in step 318 is positive, the route calculation unit 164 calculates a driving route using only the communication history acquired from the communication history map information DB 156 (step 322). If the determination in step 318 is negative, the route calculation unit 164 instructs the communication record acquisition unit 160 to acquire the communication record for the target area from the communication record management server 110. The communication record acquisition unit 160 adds the acquired communication record to the communication record map information DB 156, and the route calculation unit 164 reacquires the communication record from the communication record map information DB 156, and then calculates a driving route using the reacquired communication record (step 322).

[0114] B3) Route calculation The route calculation unit 164 of the vehicle-mounted device 102 calculates the driving route as follows. Referring to FIG. 8, a search range for the driving route is determined based on the relationship between the current position and the destination (step 350). There are various methods for determining this search range. In this embodiment, the search range is a rectangle whose diagonal is a line connecting the current position and the destination. Of course, the search range is not limited to this, and various other methods are possible.

[0115] 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 whose road width is smaller than a certain value may be excluded from the route graph.

[0116] The route calculation unit 164 applies Dijkstra's algorithm to the route graph generated in this way to generate a driving route consisting of the shortest route from the current location to the destination (step 352). The generation of the driving route at this time does not take into account the communication speed along the way. In other words, the driving route generated in step 352 is the shortest route when it is selected not to receive communication services.

[0117] Furthermore, in step 356, the route calculation unit 164 deletes from the route graph any edges with a communication speed less than half the specified bit rate. As a result, the remaining edges are equal to or greater than half the specified bit rate. In step 358, the route calculation unit 164 searches for the shortest route in this route graph. This route is the shortest route among all driving routes that are expected to use a bit rate equal to or greater than half the specified bit rate.

[0118] Furthermore, in step 360, the route calculation unit 164 deletes edges with a bit rate lower than the specified bit rate from the route graph. In the following step 362, the shortest route in the remaining route graph is searched for. The travel route obtained by this process is the shortest travel route among the travel routes that are expected to have a communication speed equal to or higher than the specified bit rate.

[0119] In this way, multiple travel routes are calculated based on the constraints specified by the user.

[0120] Note that constraints are not limited to those described above, and various other constraints are possible. To address these constraints, a program consisting of a series of procedures such as steps 352 and 354 in FIG. 8 can be prepared, and an appropriate program can be executed based on user specifications. Preferably, the order in which the programs are executed is also specified in advance. By executing the program according to such specifications, the amount of calculation required to calculate the driving route can be reduced.

[0121] B4) Display of route suggestion screen Once the driving route is calculated by the above-mentioned process, the driving unit 162 generates the route proposal screen 50 shown in Fig. 1 and displays it on the touch panel display device 116. The driving unit 162 first displays a map of the relevant area. The driving unit 162 then displays the three calculated driving routes superimposed on the map. The driving routes can be displayed by continuously drawing rectangles connecting the start and end points of each edge that forms the driving route.

[0122] The grid drawing unit 166 creates a grid display such as that shown in Fig. 1 as follows. Referring to Fig. 9, the grid drawing unit 166 acquires a geohash value representing the area displayed on the touch panel display device 116, and divides this area into a predetermined number of grid areas from the upper left to the lower right (step 370). At this time, a geohash is calculated for a predetermined position (e.g., the center position) in each grid area.

[0123] The grid drawer 166 then performs the following step 374 for each grid region.

[0124] In step 374, the grid drawing unit 166 searches the communication history map information DB 156 for records that start with the same character string as the geohash of the target grid area and whose date and time are within a predetermined range centered on the current time, and calculates the average communication speed for 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 function of communication speed, such that a low communication speed indicates a low brightness and a high communication speed indicates a high brightness.

[0125] The grid drawing unit 166 further includes a step of setting an alpha value representing semi-transparency when displaying each grid area (step 384). At this time, the grid drawing unit 166 sets the alpha value so that the grid with the highest brightness is displayed transparently. The image of the grid area created in this manner is superimposed on the image of the map and the driving route in the driving unit 162. As a result, as shown in FIG. 1, the map, the driving route, and the grid are displayed superimposed on the display surface of the touch panel display device 116. In areas where the communication speed is high, the map is displayed as is. Areas where the communication speed is low are displayed semi-transparently on the map as red areas with brightness according to the communication speed. The lower the communication speed, the darker the red the area is displayed, and the higher the communication speed, the brighter the red the area is displayed.

[0126] As described above, according to this embodiment, communication speeds actually measured in the past are stored in the communication history map information DB 156 and are used to calculate a driving route. As a result, an appropriate driving route can be calculated according to the bit rate required by the service being used. When calculating a driving route, multiple driving routes are calculated based on constraints specified by the user. The user can select an appropriate driving route depending on how they wish to use the service.

[0127] The communication speed status in the area surrounding the current location and the destination is also visually displayed, allowing the user to select an appropriate route based on the purpose of using the service, the communication status, and the distance to the destination, such as how well the communication-based services will be provided while traveling from the current location to the destination, and what route should be taken to make full use of the services.

[0128] In addition, the communication history management server 110 accumulates communication history from each vehicle. Therefore, when calculating a driving route in a certain vehicle-mounted device, if sufficient communication history is not stored in the vehicle-mounted device, the necessary communication history can be obtained from the communication history management server 110. As a result, it is possible to calculate an optimal driving route for using communication services over a wide area.

[0129] In the first embodiment, the user is allowed to select one of three driving routes displayed on the touch panel display device 116. However, this disclosure is not limited to such an embodiment. An embodiment is also possible in which a driving route that can always maintain the required communication speed is selected, or if such a route does not exist, the driving route with the highest average communication speed along the way is automatically selected.

[0130] 2. Second embodiment A.Configuration B1) Vehicle Assistance System 400 Fig. 10 shows the configuration of a vehicle assistance system 400 according to the second embodiment. Referring to Fig. 10, the vehicle assistance system 400 according to the second embodiment includes a server 108, on-board devices 402, 404, 406, etc. that use services provided by the server 108, and a communication history management server 408 that accumulates communication history data from a plurality of on-board devices, including the on-board device 402, and transmits the communication history data to each on-board device upon request.

[0131] In this embodiment, unlike the first embodiment, the route calculation unit is not located in the vehicle-mounted device 402 but is located in the communication record management server 408 .

[0132] B2) Onboard equipment 402 11, the vehicle-mounted device 402 differs from the vehicle-mounted device 102 shown in FIG. 3 in that it does not include the communication history obtaining unit 160 and the route calculating unit 164.

[0133] The driving unit 162 also differs from the driving unit 162 shown in FIG. 3 in that it requests the necessary communication history from the communication history management server 408, rather than from the communication history map information DB 156, based on information about the destination input by the user using the touch panel display device 116.

[0134] B3) Communication record management server 408 12, the communication history management server 408 includes a communication history acquisition unit 450 that acquires communication history from a plurality of in-vehicle devices, a communication history map information storage unit 202 for storing the communication history acquired by the communication history acquisition unit 450, and a route calculation unit 452 that receives a request for calculating a driving route specifying a current position and a destination from the driving unit 162 of an in-vehicle device such as the in-vehicle device 402 shown in FIG. 10, reads out communication history information of the corresponding area from the communication history map information storage unit 202, and transmits the information to the in-vehicle device 402.

[0135] B. Operation The second embodiment differs only in that, when a destination is input using the touch panel display device 116, the driving unit 162 requests communication records by specifying the current location and destination from the route calculation unit 452 of the communication record management server 408, rather than from the communication record map information DB 156, and that the route calculation unit 452 responds to this request by reading out the communication records for the relevant area from the communication record map information storage unit 202 and transmitting it to the driving unit 162. In other respects, each functional unit of the vehicle assistance system 400 operates in the same way as the corresponding functional unit in the first embodiment.

[0136] 3. Third embodiment A.Configuration A1) Vehicle Assistance System 500 13, a vehicle assistance system 500 according to the third embodiment of the present disclosure includes a server 108, in-vehicle devices 502, 504, and 506, and a communication history management server 110. The server 108 and the communication history management server 110 are the same as the server 108 and the communication history management server 110 according to the first embodiment shown in FIG.

[0137] A2) Onboard equipment 502 14, the vehicle-mounted device 502 is similar to the vehicle-mounted device 102 shown in FIG. 3. However, unlike the vehicle-mounted device 102, the vehicle-mounted device 502 includes a communication history comparison unit 552 that receives a measurement result regarding the current communication speed from the communication history recording unit 154, compares the measurement result with a communication speed estimated from information stored in the communication history map information DB 156, calculates the difference between the two, and outputs the calculated value. The vehicle-mounted device 102 also includes, instead of the communication unit 150 shown in FIG. 3, a communication unit 550 that adjusts the bit rate for the service received from the server 108 in response to the magnitude of the difference output by the communication history comparison unit 552 being greater than a threshold value. If the actual speed measured by the communication history recording unit 154 is lower than the predicted speed by the threshold value or more, the communication unit 550 requests the server 108 to reduce the bit rate of the service using the server 108. As a result, for example, if the service provided by the server 108 is something like a video stream, the server 108 reduces the video resolution or the number of transmission frames so that the service can be used continuously. Conversely, if the actual measured value is greater than the predicted value by the threshold or more, the communication unit 550 requests the server 108 to increase the bit rate used for the service if possible.

[0138] The vehicle-mounted device 502 further includes, instead of the route calculation unit 164 shown in FIG. 3 , a route calculation unit 556 having a function of redoing route calculation when the absolute value of the value output by the communication performance comparison unit 552 is greater than a threshold value, in addition to the functions of the route calculation unit 164, and instead of the communication performance transmission unit 158 ​​shown in FIG. 3 , a communication performance transmission unit 554 having a function of immediately transmitting to the server 108 a communication performance created from the latest measurement result measured by the communication performance recording unit 154 when the absolute value of the value output by the communication performance comparison unit 552 is greater than or equal to a threshold value, in addition to the functions of the communication performance transmission unit 158.

[0139] A3) Communication performance comparison unit 552 15 shows a control structure of a program realizing communication performance comparison unit 552. Referring to FIG.

[0140] Step 602 includes step 610 of receiving the latest measured value of the communication speed from communication history recording unit 154, step 612 of reading out past communication history at the current location from communication history map information DB 156, and step 614 of branching the flow of control depending on whether the difference between the latest measurement result and the communication speed in the communication history read out in step 612 is equal to or greater than a threshold value. If the determination in step 614 is negative, the processing for the latest measurement result in step 602 ends.

[0141] This program further includes step 616 of immediately transmitting the communication history obtained from the latest measurement result to the communication history management server 110 when the determination in step 614 is affirmative, step 618 of changing the communication quality with the server 108 by controlling the communication unit 550 based on the latest measurement result, and step 620 of controlling the route calculation unit 556 to execute a route change that recalculates the driving route, thereby terminating the execution of step 602. Note that in this embodiment, the result of the route change is not presented to the user, but is immediately reflected in the operation of the driving unit 162.

[0142] B. Operation 14, similar to the communication unit 150 in the other embodiments, the communication unit 550 periodically measures the communication speed when communication is being performed and the radio wave intensity when communication is not being performed, and provides the measurement results to the communication history recording unit 154. The communication history recording unit 154 operates in the same manner as in the case of FIG. 3. However, the communication history recording unit 154 also provides the latest communication history to the communication history comparing unit 552.

[0143] The communication history comparison unit 552 receives the latest communication history from the communication unit 550 (step 610 in FIG. 15 ), reads out past communication history at that point from the communication history map information DB 156 based on the current position of the in-vehicle device 502, and subtracts the speed of the past communication history from the latest measured speed (step 612). If the absolute value of the subtraction result is greater than the threshold value (the determination in step 614 is affirmative), the communication history comparison unit 552 provides the communication history based on the latest measurement result to the communication history transmission unit 554 (step 616). The communication history comparison unit 552 further provides the subtraction result obtained in step 614 to the communication unit 550 (step 618). The communication history comparison unit 552 similarly provides the communication history based on the latest measurement result to the route calculation unit 556 (step 618).

[0144] As a result, the communication history sending unit 554 immediately sends the communication history based on the latest measurement result to the communication history management server 110. The communication history management server 110 stores the received communication history in the communication history map information storage unit 202 (see FIG. 4). The communication unit 550 requests the server 108 to adjust the bit rate of the service provided by the server 108 based on the latest measurement result. The route calculation unit 556 recalculates the travel route based on the latest measurement result, and controls the driving unit 162 to change the travel route according to the result.

[0145] As described above, according to the third embodiment, if the latest measurement result regarding the communication speed significantly differs from the past communication history, the latest measurement result is immediately transmitted to the communication history management server 110 as the communication history. As a result, the latest measurement result is immediately reflected in the communication history management server 110. Similarly, the communication unit 550 changes the bit rate of the service received from the server 108 according to the communication speed determined by the latest measurement result. As a result, if the communication speed decreases, the service is changed to a service with a correspondingly lower bit rate. Conversely, if the communication speed increases, the service is changed to a service with a correspondingly higher bit rate. For example, in the case of video streaming, the image resolution or frame rate can be changed in this way according to the available communication speed to maintain the service. Furthermore, automatic route changes allow a route with better communication quality to be selected. As a result, the user can use the service under better conditions.

[0146] 4. Fourth embodiment A.Configuration A1) Driving Assistance System 650 Referring to FIG. 16, a driving assistance system 650 according to the fourth embodiment of the present disclosure includes the server 108, on-board devices such as on-board devices 652, 654, and 656, and a communication record management server 658.

[0147] The vehicle-mounted device 652 according to the fourth embodiment differs from the vehicle-mounted device 102 in that, in addition to the functions of the vehicle-mounted device 102 shown in FIG. 3, it performs statistical processing on the communication history stored in the communication history map information DB 156 and suggests driving routes based on the results of the processing.

[0148] A2) Onboard equipment 652 Referring to Figure 17, as described above, in addition to the components of the vehicle-mounted device 102 shown in Figure 3, the vehicle-mounted device 652 includes a communication statistics calculation unit 700 that performs predetermined statistical processing on communication performance information stored in the communication performance map information DB 156, a communication performance statistical information DB 702 for storing statistical information regarding communication calculated by the communication performance calculation unit 700, and a route calculation unit 704 that calculates a driving route using the communication performance statistical information stored in the communication performance statistical information DB 702.

[0149] In this embodiment, when the communication performance acquisition unit 160 receives a request to acquire communication performance information from the route calculation unit 704, it provides the route calculation unit 704 with communication performance statistics stored in the communication performance statistical information DB 702 rather than the communication performance map information DB 156. When it is difficult for the route calculation unit 704 to calculate a driving route based on the communication performance statistics stored in the communication performance statistical information DB 702, the communication performance acquisition unit 160 receives communication performance statistical information stored in the communication performance statistical information DB 702 from the communication performance management server 658. The communication performance acquisition unit 160 adds this communication performance statistical information to the communication performance statistical information DB 702 and then provides it 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 a driving route is not the actual measurement information stored in the communication performance map information DB 156 but the statistically processed information stored in the communication performance statistical information DB 702.

[0150] A3) Communication record management server 658 18, the communication performance management server 658 includes a communication performance acquisition unit 200, a communication performance map information storage unit 202, and a communication statistics calculation unit 750 for performing statistical processing similar to that performed by the communication statistics calculation unit 700 shown in Fig. 17 on communication performance information stored in the communication performance map information storage unit 202. The communication performance management server 658 further includes a communication performance statistical information storage unit 752 for storing statistical information regarding communication performance calculated by the communication statistics calculation unit 750, and a communication performance transmission unit 754 for reading out communication performance statistical information corresponding to the current location specified by the communication performance acquisition unit 160 from the communication performance statistical information storage unit 752 and transmitting the information to the communication performance acquisition unit 160 in response to a request from the communication performance acquisition unit 160 shown in Fig. 17.

[0151] Fig. 19 shows the column configuration of the communication performance statistical information DB 702 shown in Fig. 17. The communication performance statistical information storage unit 752 shown in Fig. 18 also has a similar column configuration.

[0152] Referring to Figure 19, the communication performance statistical information 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 operator column, a band number column, a cell ID column, and the same SINR, RSSI, RSRP, and RSRQ columns as shown in Figure 5.

[0153] Of the information stored in each of these columns, the date and time is used to identify the unit period that constitutes the statistical data. For example, if the date and time column contains a value indicating the year (such as "2022"), this indicates that statistics covering the entire year of 2022 constitute one record in the communication performance statistical information DB 702. If the date and time column contains information indicating a certain month (such as "202206"), it indicates that statistics covering one month relating to that information are stored in that record. Similarly, by using this date and time column, statistics for one day, one hour, etc. can each be stored as one record in the communication performance statistical information DB 702. By including date and time information in the records in this way, statistical information can be recorded hierarchically across various periods.

[0154] The grid ID is a geohash identifier that identifies the grid that is the subject of the statistics. This value is assigned fixedly to each grid. However, as mentioned above, grid IDs also have a hierarchical structure. Therefore, if you determine the smallest unit of size for a grid and record the statistical values ​​of the communication status for that grid, you can calculate statistics for larger grids at any 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.

[0155] In Figure 19, the columns below the communication speed contain values ​​after statistical processing. The statistical processing method for each of these columns varies depending on the column. For example, for communication speed, speed, direction, SINR, RSSI, RSRP, and RSRQ, representative values ​​obtained by statistical processing, such as average, maximum, minimum, and CDF (cumulative distribution function), or any combination of these, are stored. For direction, the direction may be quantified and the average taken, or 360 degrees may be divided into predetermined angles and the number of values ​​falling within each angle range may be counted. The communication line, communication carrier, band number, and cell ID are all discrete values, but for these, the values ​​used within the target unit period may be counted by type and recorded.

[0156] B. Operation In this embodiment, the communication history recording unit 154 of the in-vehicle device 652 shown in Fig. 17 periodically acquires communication history information and stores it in a communication history map information DB 156. A communication history transmitting unit 158 ​​similarly transmits the communication history information to a communication history management server 658. A communication history acquiring unit 200 of the communication history management server 658 shown in Fig. 18 acquires communication history information from multiple in-vehicle devices including the in-vehicle device 652 and stores it in a communication history map information storage unit 202.

[0157] Referring to Figure 17, in this embodiment, in the vehicle-mounted device 652, the communication statistics calculation unit 700 performs statistical processing on the communication performance information stored in the communication performance map information DB 156 according to a certain schedule, and stores the results in the communication performance statistical information DB 702.

[0158] In this case, the schedule may be one in which statistical processing is performed only once every minimum time unit described above has elapsed, or one in which statistical processing is performed every time a predetermined period longer than the minimum time unit has elapsed. However, if it is necessary to take hierarchical statistics, it may be necessary to calculate statistics for higher layers in addition to processing for the minimum time unit when performing statistical processing. When calculating statistics for higher layers, the calculation may be performed directly from information accumulated in the communication history map information DB 156, or statistical information for lower layers stored in the communication history statistical information DB 702 may be used. In this embodiment, the communication statistics calculation unit 700 uses only information from the communication history map information DB 156.

[0159] On the other hand, in the communication performance management server 658 shown in FIG. 18, the communication statistics calculation unit 750 similarly performs statistical processing on the communication performance information accumulated in the communication performance map information storage unit 202 according to a fixed schedule, and stores the obtained communication performance statistical map information in the communication performance statistical information storage unit 752.

[0160] When the route calculation unit 704 calculates a driving route, it specifies a current location and a destination and requests the communication history acquisition unit 160 to acquire communication history for the corresponding area. The communication history acquisition unit 160 selects communication history that has been subjected to statistical processing for the specified area from the information stored in the communication history statistical information DB 702 and inputs it to the route calculation unit 704. If the information obtained from the communication history statistical information DB 702 is sufficient for calculating a driving route for the specified area, the route calculation unit 704 immediately executes the route calculation process. Otherwise, the route calculation unit 704 requests the communication history acquisition unit 160 to acquire communication history statistical information for the specified area from the communication history management server 658. The communication history acquisition unit 160 acquires the requested information from the communication history statistical information storage unit 752 via the communication history transmission unit 754 of the communication history management server 658 and adds it to the communication history statistical information DB 702 in FIG. 17 . The added information is input from the communication history statistical information DB 702 to the route calculation unit 704. The route calculation unit 704 uses the statistical information on the communication performance thus obtained to calculate the route from the current position to the destination in accordance with the specified conditions.

[0161] The operations of the other components are the same as those of the vehicle-mounted devices in the first to third embodiments.

[0162] 5 Fifth embodiment The fifth embodiment is characterized by the display mode when proposing a driving route. The configuration of the in-vehicle device for this purpose is the same as that of the in-vehicle device 102 shown in Fig. 3, for example. However, in this embodiment, a grid is not superimposed on a map as in the grid drawing unit 166 shown in Fig. 3. Instead, this embodiment uses a proposed route display unit (not shown) that displays a proposed driving route in different modes depending on the communication speed assumed to be available in each grid point along the driving route, as shown in Fig. 20.

[0163] Referring to FIG. 20, in this embodiment, a 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.

[0164] The driving route display 810 displays a map, on which the current position and destination of a vehicle image 816 are superimposed as balloons 820 and 822. No grid is displayed. Instead, each portion of the image of the driving routes 830 and 832 is displayed with a hue and brightness corresponding to the communication speed of the grid to which that portion belongs. Typically, the hue is red, and the brightness is adjusted according to a monotonic function of the communication speed, increasing if the communication speed is high and decreasing if the communication speed is low. However, due to the limitations of the drawing, such changes in the display mode are not shown in FIG. 20.

[0165] In this embodiment, a representative value of the communication speed (e.g., average bit rate, the ratio of the route length at which the minimum bit rate specified by the service can be used to the entire route, etc.) is displayed in association with each travel route. An example of this is the "communication quality satisfaction level" indicated by speech bubbles 824 and 826 in FIG. 20 . For example, speech bubble 824 indicates that the communication quality satisfaction level for the first route (first travel route) is 75%. This means that the total length of the first travel route where the bit rate specified by the service can be maintained is 75% of the total length of the first travel route. For the second travel route, this value is 25%. In other words, for the first travel route, the service is available with the highest possible quality for three-quarters of the total length, but for the second travel route, it is only available for one-quarter of the total length. Displaying such a representative value has the effect of making it easier for the user to understand the communication quality for each route.

[0166] The first route predictor image display 812 and the second route predictor image display 814 represent the expected image quality of the image displayed on each driving route when the service used during driving along each driving 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 expected communication speed when traveling along each driving route to the communication speed at which the image can be received at its original resolution. As described above, if the communication quality on each route is represented numerically, the user can understand the difference, but it is difficult to intuitively grasp the difference. However, by representing the communication quality on each driving route as a difference in image, as shown in the first route predictor image display 812 and the second route predictor image display 814, the user can intuitively grasp the difference in communication quality. Note that while speech bubbles are used in this example, the communication quality display may be associated with the corresponding driving route by, for example, displaying a line connecting the communication quality display to the corresponding driving route instead of a speech bubble.

[0167] It is desirable to present such effects to the user in accordance with the type of service. For example, if the service the user is trying to use is related to audio rather than video, it is conceivable to superimpose noise according to the communication speed onto sample audio or music rather than sample images.

[0168] A control structure of a computer program for realizing the route proposal processing unit described above in relation to this embodiment is shown in Fig. 21. Referring to Fig. 21, this program includes a step 850 for setting a destination, a step 852 for acquiring the current position of the vehicle, and a step 854 for receiving from the user a specification of constraints to be used when calculating a route.

[0169] This program further includes step 856 of searching for a driving route from the current position specified in steps 850 and 852 to the destination under the constraints specified in step 856; step 858 of displaying each of the driving routes searched for in step 856 as shown in driving route display 810 of FIG. 20; step 860 of calculating a representative value representing the communication quality for each of the driving routes; and step 862 of displaying the representative value calculated in step 860 for each of the driving routes together with speech bubbles 824 and 826 having convex portions contacting the corresponding driving routes.

[0170] This program further includes step 864 of determining whether or not an image representing the communication image quality should be displayed, such as when the service is related to video, and branching the control flow according to the result of the determination, step 866 of processing a sample image prepared in advance based on the representative value calculated for each driving route in step 860 when the determination in step 864 is affirmative, and step 868 of displaying the sample image processed in step 866 at a predetermined position on the driving route display 810, as shown by first route predicted image display 812 and first route predicted image display 812 in Figure 20, and terminating execution of this program. When it is determined in step 864 that image display is unnecessary, steps 866 and 868 are not executed.

[0171] Referring to FIG. 22, step 858 in FIG. 21 includes step 900, which performs the same grid drawing process as shown in FIG. 9, and step 902, which performs step 904 for each of the grids obtained in step 900.

[0172] Step 904 includes step 910, which calculates the overlapping portion between the grid to be processed and each driving route, and step 912, which sets the alpha value of each pixel for each overlapping portion calculated in step 910 so that the overlapping portion is displayed semi-transparently and the remaining portion is displayed transparently, thereby ending step 904.

[0173] By this process, any part of the grid that does not overlap with the driving route is displayed transparently. In other words, the map is displayed as is. For any part of the grid that overlaps with the driving route, the overlapping part is displayed with the hue and brightness set in the process of step 900, but the part other than the overlapping part is displayed transparently. As a result, each part of each driving route is displayed in a different manner (hue and brightness) depending on the communication quality (communication speed) of that part. The map is displayed in the part other than the driving route. In other words, a display such as that shown by driving route display 810 in FIG. 20 is obtained.

[0174] As described above, this fifth embodiment also visually displays the communication quality of the proposed driving route, allowing the user to select the driving route that they consider to be optimal based on the service they wish to use and the time required to reach their destination.

[0175] 6. Computer implementation A) On-board device hardware The in-vehicle devices according to this disclosure, such as those shown in Fig. 2, are realized by a microcontroller unit (MCU) and a communication device as hardware, and a program executed by the MCU. Fig. 23 shows the configuration of the MCU 950 in block form.

[0176] 23, the MCU 950 includes an MPU (Micro Processing Unit) 952 as a processor, a high-speed bus 978 to which the MPU 952 is connected, an SRAM (Static Random Access Memory) 954 connected to the high-speed bus 978, a flash memory 956 connected to the high-speed bus 978, and a ROM (Read-Only Memory) 958 connected to the high-speed bus 978. The SRAM 954 holds data necessary for executing programs, etc. The flash memory 956 stores a program 976 for implementing each function implemented by the vehicle-mounted device according to the first to fifth embodiments. The ROM 958 stores a boot-up program for the MPU 952, etc.

[0177] The MCU further includes a low-speed bus 960 connected to a high-speed bus 978 via a bridge 962, a serial I / F (Interface) 964, an ADC (Analog-to-Digital Converter) 966, a timer / counter 968, a clock generator 970, a power supply control unit 972, and a general-purpose I / F 974, all of which are connected to the low-speed bus 960.

[0178] The operation of the MCU is well known, and what is meaningful in the embodiment is the function of the program it executes, so the operation of the MCU itself will not be repeated in the following explanation.

[0179] B) Server Hardware Fig. 24 is an external view of an example of a computer system that realizes the communication record management servers 110 and 408 and the communication record management server 658 according to the above-described embodiments. Fig. 25 is a block diagram showing an example of the hardware configuration of the computer system shown in Fig. 24.

[0180] 24, this computer system 1050 includes a computer 1070 having a DVD (Digital Versatile Disc) drive 1102, and a keyboard 1074, a mouse 1076, and a monitor 1072 for interacting with a user, all of which are connected to the computer 1070. Of course, these are just one example of a configuration for when user interaction is required, and any general hardware and software that can be used for user interaction (for example, a touch panel, voice input, or a general pointing device) can be used.

[0181] 25, computer 1070 includes, in addition to DVD drive 1102, a CPU (Central Processing Unit) 1090, a GPU (Graphics Processing Unit) 1092, a bus 1110 connected to CPU 1090, GPU 1092, and DVD drive 1102, a ROM 1096 connected to bus 1110 and storing a boot-up program of computer 1070, a RAM (Random Access Memory) 1098 connected to bus 1110 and storing instructions constituting programs, system programs, working data, and the like, and an SSD (Solid State Drive) 1100 which is non-volatile memory connected to bus 1110. SSD 1100 is used to store programs executed by CPU 1090 and GPU 1092, data used by the programs executed by CPU 1090 and GPU 1092, and the like. The computer 1070 further includes a network I / F 1108 that provides connection to a network 1086 that enables communication with other terminals, and a USB port 1106 to which a USB (Universal Serial Bus) memory 1084 can be attached or detached and that provides communication between the USB memory 1084 and each part within the computer 1070.

[0182] The computer 1070 further includes an input / output I / F 1104 that is connected to external devices such as a microphone 1082 and a speaker 1080 and to a bus 1110, and that reads out audio signals, video signals, and text data generated by the CPU 1090 and stored in the RAM 1098 or SSD 1100 according to instructions from the CPU 1090, converts the signals to analog, amplifies the signals, and drives the speaker 1080, and digitizes the analog audio signals from the microphone 1082 and stores them at any address in the RAM 1098 or SSD 1100 specified by the CPU 1090.

[0183] The programs and parameters for realizing the communication record management servers 110, 408, and 658 in the above embodiments, as well as the sample images used in the fifth embodiment, are all stored in, for example, the SSD 1100, RAM 1098, DVD 1078, or USB memory 1084 shown in Fig. 25, or a storage medium of an external device (not shown) connected via the network I / F 1108 and network 1086. Typically, these data and parameters are written to the SSD 1100 from outside, for example, and loaded into the RAM 1098 when executed by the computer 1070.

[0184] Computer programs for operating this computer system to realize the functions of the communication history management servers 110 and 408, the communication history management server 658, and each of their components are stored on a DVD 1078 inserted into a DVD drive 1102, and transferred from the DVD drive 1102 to the SSD 1100. Alternatively, these programs may be stored on a USB memory 1084, and the USB memory 1084 may be inserted into a USB port 1106 and the programs transferred to the SSD 1100. Alternatively, the programs may be sent to the computer 1070 via a network 1086 and stored in the SSD 1100.

[0185] The program is loaded into RAM 1098 when executed. Of course, a source program may be entered using keyboard 1074, monitor 1072, and mouse 1076, and the compiled object program may be stored in SSD 1100. In the case of a scripting language, a script entered using keyboard 1074 or the like may be stored in SSD 1100. In the case of a program that runs on a virtual machine, a program that functions as a virtual machine must be installed in computer 1070 in advance. Because execution of the above program involves a large amount of calculation, it is preferable to realize each part of the embodiment of the present invention as an object program made up of native computer code, particularly the program portion that performs numerical calculations, rather than using a scripting language.

[0186] The CPU 1090 reads a program from the RAM 1098 according to an address indicated by an internal register called a program counter (not shown), interprets the instructions, reads data required to execute the instructions from the RAM 1098, the SSD 1100, or another device according to the address specified by the instruction, and executes the processing specified by the instruction. The CPU 1090 stores the execution result data at an address specified by the program, such as in the RAM 1098, the SSD 1100, or a register within the CPU 1090. At this time, the value of the program counter is also updated by the program. The computer program may be loaded directly into the RAM 1098 from the DVD 1078, the USB memory 1084, or via a network. Note that some tasks (mainly numerical calculations) within the program executed by the CPU 1090 are dispatched to the GPU 1092 according to instructions included in the program or according to the analysis results obtained when the CPU 1090 executes the instructions.

[0187] A program that cooperates with computer 1070 to implement the functions of each unit according to the above-described embodiment includes a plurality of instructions written and arranged to cause computer 1070 to operate to implement those functions. Some of the basic functions required to execute these instructions are provided by an operating system (OS) or third-party programs running on computer 1070, or by modules of various toolkits installed on computer 1070. Therefore, the program does not necessarily include all of the functions required to implement the system and method of this embodiment. The program need only include instructions that execute the operations of the above-described devices and their components by statically linking appropriate functions or "programming toolkit" functions in a controlled manner to achieve the desired results, or by dynamically linking to those functions during program execution. The method for operating computer 1070 in this manner is well known and will not be repeated here.

[0188] The GPU 1092 is capable of parallel processing, and can simultaneously execute a large amount of calculations associated with, for example, path search processing, statistical processing, etc. in parallel or pipelined fashion. For example, parallel calculation elements discovered in a program when the program is compiled, or parallel calculation elements discovered during program execution, are dispatched from the CPU 1090 to the GPU 1092 as needed, and executed, with the results returned to the CPU 1090 directly or via a predetermined address in the RAM 1098, and assigned to a predetermined variable in the program.

[0189] 7. Additional Notes Other embodiments of this disclosure are described below.

[0190] (1) The in-vehicle device is an in-vehicle device that provides driving assistance to a vehicle by communicating with a predetermined driving assistance server, and may include: a location information acquisition device for acquiring location information of a vehicle equipped with a communication device; an information transmission unit that measures communication quality by the communication device and transmits communication performance information to the server, the communication performance information including the measured communication quality, location information acquired by the location information acquisition device when the communication quality was measured, and measurement time information that identifies the time when the communication quality was measured; a driving route creation request unit that transmits a driving route creation request including the current location and destination of the vehicle to the server in response to a destination of the vehicle being specified; a driving route information acquisition unit that acquires driving route information that identifies multiple driving routes and is sent by the server in response to the driving route creation request; and a route display device that displays multiple driving routes identified by the driving route information acquired by the driving route information acquisition unit.

[0191] (2) The in-vehicle device is an in-vehicle device that provides driving assistance to a vehicle by communicating with a predetermined driving assistance server, and includes: a location information acquisition device for acquiring location information of a vehicle equipped with a communication device; a measurement unit for measuring communication quality by the communication device; an information transmission unit for transmitting communication performance information to the server according to a predetermined transmission schedule, the communication performance information including the communication quality measured by the measurement unit, location information acquired by the location information acquisition device when measuring the communication quality, and measurement time information specifying the time when the communication quality was measured; a communication performance map information storage unit for acquiring and storing communication performance information collected by the server from a plurality of in-vehicle devices; and a communication performance map information storage unit for storing, in response to a destination of the vehicle being specified, a service available using the communication device when required. the communication performance comparison unit compares the communication quality measured by the measurement unit at a location where the vehicle equipped with the on-board device is traveling with a predicted communication quality predicted based on the communication performance information at the location stored in the communication performance map information storage unit, and calculates the difference therebetween; and an off-schedule transmission unit transmits, in response to the absolute value of the difference being equal to or greater than a threshold, communication performance information to a server, the communication performance information including the measured communication quality, location information acquired by the location information acquisition device when the communication quality was measured, and measurement time information that identifies the time when the communication quality was measured.

[0192] (3) In (2) above, the vehicle-mounted device may further include a route recalculation unit that recalculates multiple driving routes for the vehicle from the current position of the vehicle to the destination in response to the absolute value of the difference being equal to or greater than a threshold value.

[0193] (4) The in-vehicle device may include: a location information acquisition device for acquiring location information of a vehicle equipped with a communication device; a communication performance map information storage unit for storing a map of an area passable by the vehicle and performance information on communication quality in the area; an information transmission unit for measuring communication quality by the communication device and transmitting communication performance information to a server, the communication performance information including the measured communication quality, location information acquired by the location information acquisition device when the communication quality was measured, and measurement time information specifying the time when the communication quality was measured; a communication performance statistical information storage unit for acquiring from the server, statistical information on communication performance on communication quality in the area collected by multiple in-vehicle devices, and storing the acquired information; a statistical information update unit for updating the statistical information on communication performance stored in the communication performance statistical information storage unit using the performance information stored in the communication performance map information storage unit; a route calculation unit for calculating, in response to a destination of the vehicle being specified, multiple driving routes for the vehicle from the current location of the vehicle to the destination based on the communication quality required for a service available using the communication device and the statistical information stored in the communication performance statistical information storage unit; and a route display device for displaying the multiple driving routes calculated by the route calculation unit.

[0194] (5) The in-vehicle device may include: a location information acquisition device for acquiring location information of a vehicle equipped with a communication device; a communication performance map information storage unit for storing a map of an area passable by the vehicle and performance information on communication quality in the area; an information transmission unit for measuring communication quality by the communication device and transmitting communication performance information to a server, the communication performance information including the measured communication quality, location information acquired by the location information acquisition device when the communication quality was measured, and measurement time information specifying the time when the communication quality was measured; a communication performance statistical information storage unit for acquiring and storing statistical information on communication performance on communication quality in the area collected by multiple in-vehicle devices from the server; a statistical information update unit for updating the statistical information on communication performance stored in the communication performance statistical information storage unit using the performance information stored in the communication performance map information storage unit; a route calculation unit for calculating, in response to a destination of the vehicle being specified, multiple driving routes for the vehicle from the current location of the vehicle to the destination based on the communication quality required for a service available using the communication device and the statistical information stored in the communication performance statistical information storage unit; and a route display device for displaying the multiple driving routes calculated by the route calculation unit.

[0195] (6) The in-vehicle device may include a location information acquisition device for acquiring location information of a vehicle equipped with a communication device; an information transmission unit that measures communication quality by the communication device and transmits communication performance information to a server, the communication performance information including the measured communication quality, location information acquired by the location information acquisition device when the communication quality was measured, and measurement time information that identifies the time when the communication quality was measured; a driving route request unit that, in response to a request to calculate a driving route by specifying a destination of the vehicle and an instruction to calculate a driving route, specifies the current location of the vehicle and the destination and transmits a request to the server to calculate a driving route; and a route display device that receives driving route information transmitted from the server in response to the request and displays the driving route identified by the driving route information.

[0196] (7) The driving assistance server may include a communication performance information storage unit that receives and stores communication performance information from multiple on-board devices, the communication performance information including the communication quality measured by each on-board device, location information indicating the location of each on-board device at the time the communication quality was measured, and measurement time information that identifies the time the communication quality was measured; a route calculation unit that, in response to a request from a first on-board device requesting that a destination be specified and multiple driving routes be calculated, calculates multiple driving routes for a vehicle equipped with the first on-board device from the current location of the vehicle to the destination based on the communication quality required for a service available to the first on-board device using the communication device and information stored in the communication performance map information storage unit; and a driving route transmission unit that transmits the multiple driving routes calculated by the route calculation unit to the first on-board device.

[0197] (8) The driving assistance server may include a communication performance acquisition unit that acquires, from an in-vehicle device, communication performance information including communication quality, location information indicating the location of the in-vehicle device, and measurement time information that specifies the time when the communication quality was measured; a communication performance map information storage unit that stores a map of an area passable by the vehicle and the communication performance information acquired by the communication performance acquisition unit from the multiple in-vehicle devices; a communication performance statistical information calculation unit that calculates statistical information of communication performance regarding communication quality in the area stored in the communication performance map information storage unit; and a statistical information distribution unit that distributes the statistical information calculated by the communication performance statistical information calculation unit to the multiple in-vehicle devices according to a predetermined distribution schedule.

[0198] (9) The driving assistance server may include a communication performance acquisition unit that acquires, from an in-vehicle device, communication performance information including communication quality, location information indicating the location of the in-vehicle device, and measurement time information that identifies the time when the communication quality was measured; a communication performance map information storage unit for storing a map of an area passable by the vehicle and communication performance information acquired from the multiple in-vehicle devices by the communication performance acquisition unit; a communication performance statistical information calculation unit that calculates statistical information of communication performance regarding communication quality in the area stored in the communication performance map information storage unit; a route calculation unit that, in response to a request from the first in-vehicle device requesting calculation of multiple driving routes by specifying a destination, calculates multiple driving routes for a vehicle equipped with the first in-vehicle device from the current location of the first vehicle to the destination based on the communication quality required for a service available to the first in-vehicle device using the communication device and the information stored in the communication performance statistical information storage unit; and a driving route transmission device that transmits the multiple driving routes calculated by the route calculation unit to the first in-vehicle device.

[0199] (10) A driving assistance method is a driving assistance method in a driving assistance system including an on-board device equipped with a communication device and a server for providing driving assistance to a vehicle equipped with the on-board device, the method including: a step in which the on-board device acquires location information of the vehicle equipped with the communication device; a step in which the on-board device stores a map of an area passable by the vehicle and performance information on communication quality in the area in a storage device; a step in which the on-board device measures communication quality by the communication device and transmits communication performance information to the server, the communication performance information including the measured communication quality, location information acquired by a location information acquisition device when the communication quality was measured, and measurement time information identifying the time when the communication quality was measured; a step in which the server acquires communication performance information from a plurality of on-board devices; The method may include a step of storing the communication history information acquired in the step of acquiring communication history information in a communication history map information storage device; a step by the server distributing the communication history information stored in the communication history map information storage unit to a plurality of in-vehicle devices; a step by the in-vehicle devices adding the communication history information distributed by the server to a storage device; a step by the in-vehicle devices calculating a plurality of driving routes for the vehicle from the current position of the vehicle to the destination based on the communication quality required for available services using the communication device and the information stored in the storage device in response to a request to calculate a planned driving route by specifying a destination of the vehicle; and a step of displaying the plurality of driving routes calculated in the route calculation step on a display device.

[0200] (11) A driving assistance method may be a driving assistance method implemented by a computer using an on-board device that provides driving assistance for a vehicle by communicating with a predetermined driving assistance server, and may include the steps of: the computer acquiring location information of a vehicle equipped with a communication device; the computer storing a map of an area passable by the vehicle and historical information on communication quality in the area in a storage device; the computer measuring communication quality by the communication device and transmitting communication historical information to the server, the communication historical information including the measured communication quality, location information of the on-board device at the time of measuring the communication quality, and measurement time information specifying the time of measuring the communication quality; the computer acquiring communication historical information on communication quality in the area collected by multiple on-board devices from the server and adding it to the storage device for storage; the computer calculating, in response to a destination of the vehicle being specified, multiple driving routes for the vehicle from the current location of the vehicle to the destination based on the communication quality required for available services using the communication device and the information stored in the storage device; and the computer displaying the multiple driving routes calculated in the route calculating step on a route display device.

[0201] (12) The driving assistance method may be a driving assistance method implemented by a computer using an on-board device that provides driving assistance to a vehicle by communicating with a predetermined driving assistance server, and may include the steps of: the computer acquiring location information of a vehicle equipped with a communication device; the computer measuring communication quality by the communication device and transmitting communication performance information to the server, the communication performance information including the measured communication quality, location information acquired when the communication quality was measured, and measurement time information identifying the time when the communication quality was measured; the computer transmitting a driving route creation request to the server in response to a destination of the vehicle being specified, the driving route creation request including the current location and destination of the vehicle; the computer acquiring driving route information that identifies multiple driving routes and that is transmitted by the server in response to the driving route creation request; and the computer displaying, on a display device, the multiple driving routes identified by the driving route information acquired in the step of acquiring driving route information.

[0202] (13) A driving assistance method is a driving assistance method implemented by a computer using an in-vehicle device that assists driving of a vehicle by communicating with a predetermined driving assistance server, the method including: a step in which the computer acquires location information of a vehicle equipped with a communication device; a step in which the computer measures communication quality by the communication device; a step in which the computer transmits communication performance information to the server according to a predetermined transmission schedule, the communication performance information including the communication quality measured in the measuring step, location information acquired at the time of measuring the communication quality, and measurement time information that identifies the time of measuring the communication quality; a step in which the computer acquires communication performance information collected by the server from a plurality of in-vehicle devices and stores it in a storage device; and a step in which the computer transmits communication performance information of the vehicle equipped with a communication device according to a predetermined transmission schedule, the communication performance information including the communication quality measured in the measuring step, location information acquired at the time of measuring the communication quality, and measurement time information that identifies the time of measuring the communication quality. The method may include a step of calculating, in response to a destination being specified, a plurality of driving routes for the vehicle from the current position of the vehicle to the destination based on the communication quality required for available services using the communication device and information stored in the storage device; a step of the computer comparing the communication quality measured at a point where the vehicle equipped with the on-board device is traveling with the predicted communication quality predicted based on communication performance information at the point stored in the storage device and calculating the difference; and a step of the computer transmitting, in response to the absolute value of the difference being equal to or greater than a threshold, communication performance information to a server, the communication performance information including the measured communication quality, location information obtained when the communication quality was measured, and measurement time information specifying the time when the communication quality was measured.

[0203] (14) A driving assistance method may include the steps of: a computer acquiring location information of a vehicle equipped with a communication device; a computer storing in a storage device a map of areas passable by the vehicle and historical information on communication quality in the areas; a computer measuring communication quality by the communication device and transmitting communication historical information to a server, the communication historical information including the measured communication quality, location information acquired when the communication quality was measured, and measurement time information specifying the time when the communication quality was measured; a computer acquiring from the server, statistical information on communication historical information on communication quality in the area collected by multiple on-board devices and storing the information in a storage device; a computer updating the statistical information on communication historical information stored in the storage device using the historical information stored in the storage device; a computer calculating, in response to a destination of the vehicle being specified, multiple driving routes for the vehicle from the current location of the vehicle to the destination based on the communication quality required for available services using the communication device and the statistical information stored in the storage device; and a computer displaying on a display device the multiple driving routes calculated in the route calculating step.

[0204] (15) A driving assistance method may include the steps of: a computer acquiring location information of a vehicle equipped with a communication device; a computer storing in a storage device a map relating to an area passable by the vehicle and historical information relating to communication quality in the area; a computer measuring communication quality by the communication device and transmitting communication historical information to a server, the communication historical information including the measured communication quality, location information acquired when the communication quality was measured, and measurement time information specifying the time when the communication quality was measured; a computer acquiring from the server, statistical information of communication historical information relating to communication quality in the area collected by a plurality of in-vehicle devices and storing the statistical information of communication historical information stored in the storage device; a computer updating the statistical information of communication historical information stored in the storage device using the historical information stored in the storage device; a computer calculating, in response to a destination of the vehicle being specified, a plurality of driving routes for the vehicle from the current location of the vehicle to the destination based on the communication quality required for available services using the communication device and the statistical information stored in the storage device; and a computer displaying on a display device the plurality of driving routes calculated in the route calculating step.

[0205] (16) The driving assistance method may include the steps of: a computer acquiring location information of a vehicle equipped with a communication device; a computer measuring communication quality by the communication device and transmitting communication performance information to a server, the communication performance information including the measured communication quality, location information acquired by a location information acquisition device when the communication quality was measured, and measurement time information specifying the time when the communication quality was measured; a computer specifying the current location and destination of the vehicle in response to an instruction to calculate a driving route and transmitting a request to the server to calculate the driving route; and a computer receiving driving route information transmitted from the server in response to the request and displaying the driving route specified by the driving route information on a display device.

[0206] (17) The driving assistance method may include a step in which a computer receives communication performance information from a plurality of on-board devices, the communication performance information including communication quality measured by each on-board device, location information indicating the location of each on-board device at the time of measuring the communication quality, and measurement time information specifying the time of measuring the communication quality, and stores the communication performance information in a storage device; and a step in which the computer distributes the communication performance information stored in the storage device to each of the plurality of on-board devices according to a predetermined schedule.

[0207] (18) The driving assistance method may include a step in which a computer receives communication performance information from a plurality of on-board devices, the communication performance information including the communication quality measured by each on-board device, location information indicating the location of each on-board device at the time the communication quality was measured, and measurement time information specifying the time the communication quality was measured, and stores the information in a storage device; a step in which, in response to a request from a first on-board device requesting that a destination be specified and that multiple driving routes be calculated, the computer calculates multiple driving routes of a vehicle equipped with the first on-board device from the current location of the vehicle to the destination based on the communication quality required for a service available to the first on-board device using the communication device and the information stored in the storage device; and a step in which the computer transmits the multiple driving routes calculated in the driving route calculation step to the first on-board device.

[0208] (19) The driving assistance method may include the steps of: a computer acquiring, from an in-vehicle device, communication performance information including communication quality, location information indicating the location of the in-vehicle device, and measurement time information specifying the time when the communication quality was measured; a computer storing, in a storage device, a map of an area passable by the vehicle and the communication performance information acquired from the multiple in-vehicle devices in the step of acquiring the communication performance information; a computer calculating, in the storage device, statistical information of the communication performance regarding the communication quality in the area; and a computer distributing, to the multiple in-vehicle devices, the statistical information calculated in the step of calculating the statistical information of the communication performance according to a predetermined distribution schedule.

[0209] (20) The driving assistance method may include the steps of: a computer acquiring, from an in-vehicle device, communication performance information including communication quality, location information indicating the location of the in-vehicle device, and measurement time information specifying the time when the communication quality was measured; a computer storing, in a storage device, a map of an area passable by the vehicle and the communication performance information acquired from the multiple in-vehicle devices in the step of acquiring communication performance; a computer calculating statistical information of the communication performance regarding the communication quality in the area stored in the storage device; a computer calculating, in response to a request from a first in-vehicle device requesting that a destination be specified and multiple driving routes be calculated, multiple driving routes of a vehicle equipped with the first in-vehicle device from a current location of the first vehicle to the destination based on the communication quality required for a service available to the first in-vehicle device and the information stored in the storage device using the communication device; and a computer transmitting the multiple driving routes calculated in the step of calculating the multiple driving routes to the first in-vehicle device.

[0210] (21) The computer program may cause a computer to function to execute the driving assistance method according to any one of (10) to (20) above.

[0211] (22) A computer-readable non-transitory storage medium may store the computer program described in (21) above.

[0212] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present disclosure is not defined by the detailed description of the disclosure, but by the claims of the appended claims, and is intended to include all modifications within the meaning and scope equivalent to the wording of the claims. [Explanation of symbols]

[0213] 50 Route suggestion screen 60 vehicles 62 Current location 64 Destination 66 Route 1 68 Route 2 100, 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 116 Touch panel display device 150, 550 Communications Department 152 CAN 154 Communication performance record section 156 Communication performance map information DB 158, 204, 554, 754 Communication performance transmission section 160, 200, 450 Communication performance acquisition section 162 Driving Department 164, 452, 556, 704 Route calculation section 166 Grid drawing section 202 Communication record map information storage unit 552 Communication Performance Comparison Section 650 Driver Assistance System 700, 750 Communication Statistics Calculation Unit 702 Communication Performance Statistical Information DB 752 Communication performance statistical information storage unit 800 display 810 Driving route display 812 First route prediction image display 814 Second route prediction image display 816 vehicle images 820, 822, 824, 826 speech bubbles 830 Travel 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 supply control unit 974 General-purpose I / F 976 Programs 978 Express Bus 1050 Computer Systems 1070 Computer 1072 monitor 1074 keyboard 1076 Mouse 1078 DVD 1080 speaker 1082 microphone 1084 USB memory 1086 Network 1090 CPU 1092 GPU 1098 RAM 1100 SSD 1102 DVD drive 1104 Input / Output Interface 1106 USB port 1108 Network I / F 1110 Bus

Claims

1. a communication performance map information storage unit for storing a map relating to an area passable by a vehicle and performance information relating to communication quality within the area; a route calculation unit that, in response to a destination of the vehicle being designated, calculates a plurality of travel routes for the vehicle from a current position of the vehicle to the destination based on a communication quality required for an available service using a communication device and the information stored in the communication record map information storage unit; a route display unit that displays the plurality of driving routes calculated by the route calculation unit on a display device.

2. 2. The driving assistance system according to claim 1, wherein the route display unit divides at least a portion of the area through which the plurality of driving routes calculated by the route calculation unit pass into a plurality of grid areas, and displays each of the grid areas with different attributes according to communication quality in the grid areas, superimposed on the display by the route display unit.

3. 3. The driving assistance system according to claim 2, wherein the route display unit changes the hue, brightness, or saturation of each of the plurality of grid areas as a monotonic function of the communication quality value in that grid area, and displays the hue, brightness, or saturation superimposed on the display by the route display unit.

4. 2. The driving assistance system according to claim 1, wherein the route display unit displays each of the plurality of travel routes calculated by the route calculation unit and a communication quality available on the travel route in association with each of the plurality of travel routes.

5. a representative value calculation unit for calculating a statistical representative value of communication quality available for each of the plurality of travel routes based on the performance information stored in the communication performance map information storage unit; a representative value display unit that displays the statistical representative value calculated for the plurality of travel routes by the representative value calculation unit by superimposing it on a display by the route display device, 2. The driving assistance system according to claim 1, wherein the route display unit superimposes a display on the display device that visually associates the statistical representative value displayed by the representative value display unit with a display corresponding to the statistical representative value among the displays of the plurality of driving routes by the route display device.

6. 6. The driving assistance system according to claim 5, wherein the route display unit displays a line connecting the statistical representative value displayed by the representative value display unit and a display corresponding to the statistical representative value among the displays of the plurality of driving routes by the route display device, superimposed on the display by the route display device.

7. 6. The driving assistance system according to claim 5, wherein the related display unit displays a speech bubble having a convex portion surrounding the statistical representative value displayed by the representative value display unit and connected to a display corresponding to the statistical representative value among the displays of the plurality of driving routes by the route display unit, superimposed on the display by the route display unit.

8. a representative value calculation unit for calculating a statistical representative value of communication quality available for each of the plurality of travel routes based on the performance information stored in the communication performance map information storage unit; an image storage device for storing still images or moving images; an image processing unit that generates a representative image from the still image or moving image stored in the image storage device, the representative image having an image quality corresponding to the statistical representative value calculated by the representative value calculation unit; 2. The driving assistance system according to claim 1, further comprising: a representative image display unit that displays, on the display device, representative images generated by the image processing unit in association with the plurality of driving routes displayed by the route display device.

9. The path calculation unit a communication quality constraint unit that determines a plurality of different constraints regarding communication quality that should be satisfied by the plurality of travel routes based on communication quality required by services available using the communication device; 9. The driving assistance system according to claim 1, further comprising: a multiple route calculation unit that, in response to a destination of the vehicle being specified, calculates, based on the information stored in the communication history map information storage unit, a plurality of driving routes that satisfy each of the plurality of constraints determined by the communication quality constraint unit and that have the shortest driving distance from the current position of the vehicle to the destination under the constraints.

10. The plurality of constraints include at least Communication quality is not restricted, The communication quality is equal to or higher than a predetermined quality throughout the travel route, or The communication quality is equal to or higher than a first quality sufficient to use a predetermined first service in a first portion of the travel route, and is equal to or higher than a second quality sufficient to use a second service that is lower than the first quality but substitutes for the predetermined first service in a second portion of the travel route. The driving assistance system of claim 9, further comprising the constraint:

11. moreover, a location information acquisition device for acquiring location information of a vehicle equipped with a communication device; 11. The driving assistance system according to claim 1, further comprising a communication history update unit that collects a record of communication quality by the communication device while the vehicle is traveling on any of the plurality of travel routes, and updates the record information stored in the communication history map information storage unit using the collected communication quality.

12. 12. The driving assistance system according to claim 11, further comprising a route calculation re-execution unit that causes the route calculation unit to re-execute route calculation in response to a difference between the actual communication quality collected by the communication history update unit for a driving route on which the vehicle is traveling and the communication quality predicted for the driving route based on the communication history map information storage unit being equal to or greater than a threshold value.

13. further comprising a statistics calculation unit that calculates statistics for each unit time for each of the plurality of grid areas based on the performance information stored in the communication performance map information storage unit, the communication performance map information storage unit further stores the statistics in addition to the performance information; 13. The driving assistance system according to claim 1, wherein the route calculation unit includes a statistical route calculation unit that, in response to a destination of the vehicle being specified, calculates a plurality of driving routes for the vehicle from a current position of the vehicle to the destination based on a communication quality required for a service available using the communication device and the statistics stored in the communication history map information storage unit.

14. 2. The driving assistance system according to claim 1, wherein the route display device includes a communication quality-based route display device that displays each portion of the plurality of driving routes with different display attributes depending on the communication quality in the grid area that overlaps with the portion.

15. The driving assistance system of claim 14 , wherein the display attributes include hue, brightness, or saturation of each portion of the plurality of driving routes.

16. The driving assistance system according to claim 15, wherein the brightness or saturation is set to be high if the communication quality is good and low if the communication quality is poor.

17. 17. A driving assistance system according to claim 15 or claim 16, wherein the hue is red.

18. 18. The driving assistance system according to claim 1, further comprising a communication history storage unit that acquires history information regarding communication quality in each of the plurality of grid areas from a plurality of in-vehicle devices and stores the information in the communication history map information storage unit.

19. A driving assistance system including an in-vehicle device equipped with a communication device and a server for providing driving assistance to a vehicle equipped with the in-vehicle device, The in-vehicle device a location information acquisition device for acquiring location information of a vehicle equipped with a communication device; a communication performance map information storage unit for storing a map relating to an area passable by a vehicle and performance information relating to communication quality in the area; an information transmission unit that measures communication quality by the communication device and transmits to the server communication performance information including the measured communication quality, the location information acquired by the location information acquisition device when the communication quality was measured, and measurement time information that specifies the time when the communication quality was measured; the server includes a communication history information acquisition unit that acquires the communication history information from a plurality of in-vehicle devices; a communication history map information storage unit that stores the communication history information acquired by the communication history information acquisition unit; a communication history distribution unit that distributes the communication history information stored in the communication history map information storage unit to the plurality of in-vehicle devices, the in-vehicle device further includes a communication history information adding unit that adds the communication history information distributed by the server to the communication history map information storage unit; a route calculation unit that, in response to a request for calculation of a planned driving route by specifying a destination of the vehicle, calculates a plurality of driving routes for the vehicle from a current position of the vehicle to the destination based on a communication quality required for a service available using the communication device and information stored in the communication record map information storage unit; a route display device that displays the plurality of driving routes calculated by the route calculation unit.

20. An in-vehicle device that provides driving assistance for a vehicle by communicating with a predetermined driving assistance server, a location information acquisition device for acquiring location information of a vehicle equipped with a communication device; a communication performance map information storage unit for storing a map relating to an area passable by a vehicle and performance information relating to communication quality in the area; an information transmission unit that measures communication quality by the communication device and transmits to the server communication performance information including the measured communication quality, the location information acquired by the location information acquisition device when the communication quality was measured, and measurement time information that specifies the time when the communication quality was measured; a communication history map information adding unit that acquires communication history information relating to communication quality in the area collected by a plurality of in-vehicle devices from the server and adds and stores the information in the communication history map information storage unit; a route calculation unit that, in response to a destination of the vehicle being specified, calculates a plurality of travel routes for the vehicle from a current position of the vehicle to the destination based on a communication quality required for a service available using the communication device and information stored in the communication record map information storage unit; a route display device that displays the plurality of travel routes calculated by the route calculation unit.

21. a communication performance information storage unit that receives and stores communication performance information from a plurality of in-vehicle devices, the communication performance information including communication performance information relating to communication quality measured by each in-vehicle device, location information indicating the location of each in-vehicle device at the time of measuring the communication performance information, and measurement time information specifying the time of measuring the communication quality; a communication history distribution unit that distributes the communication history information stored in the communication history information storage unit to each of a plurality of in-vehicle devices according to a predetermined schedule.

22. a step in which a computer stores in a storage device a map relating to an area where the vehicle can travel and performance information relating to communication quality in the area; a step of calculating, by a computer, in response to a destination of the vehicle being specified, a plurality of travel routes of the vehicle from a current position of the vehicle to the destination based on communication qualities required by available services using a communication device and the information stored in the storage device; and a step of displaying, by a computer, the plurality of travel routes calculated in the route calculation step on a display device.

23. A computer program product that causes a computer to perform the driving assistance method according to claim 22.

24. Computer, a location information acquisition device for acquiring location information of a vehicle equipped with a communication device; a communication performance map information storage unit for storing a map relating to an area passable by a vehicle and performance information relating to communication quality in the area; an information transmission unit that measures communication quality by the communication device and transmits communication performance information to a server, the communication performance information including the measured communication quality, the location information acquired by the location information acquisition device when the communication quality was measured, and measurement time information that identifies the time when the communication quality was measured; a communication history map information adding unit that acquires communication history information relating to communication quality in the area collected by a plurality of in-vehicle devices from the server and adds and stores the information in the communication history map information storage unit; a route calculation unit that, in response to a destination of the vehicle being specified, calculates a plurality of travel routes for the vehicle from a current position of the vehicle to the destination based on a communication quality required for a service available using the communication device and information stored in the communication record map information storage unit; a computer program that causes the computer to function as a route display device that displays the plurality of travel routes calculated by the route calculation unit;

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