JP2015032968A - On-vehicle device, channel selection method, and channel selection program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide "an on-vehicle device, channel selection method, and channel selection program" capable of selecting an optimum channel on the basis of wireless frequency information on the periphery of a running path of a vehicle when the on-vehicle device connects with a terminal device.SOLUTION: An on-vehicle device 30 comprises: wireless LAN communication means 140 for enabling communication with a smart phone 40 by a wireless LAN; own vehicle position identification means 142 for identifying a position of a vehicle mounting the on-vehicle device; path search means 144 for searching for a path from the identified position of the vehicle to a destination; channel information acquisition means 146 for acquiring channel information used at the position of the vehicle or the periphery of the searched path; channel selection means 148 for selecting an optimum channel on the basis of the acquired channel information; communication control means 150 for controlling the communication means 140 so as to connect with the smart phone 40 by using the selected channel; and communication state detection means 152 for monitoring a communication state to detect reduction in communication speed.

Description

  The present invention relates to a network connection between an in-vehicle device and a terminal device, and more particularly to a technique of a channel selection method when the in-vehicle device wirelessly connects the terminal device.

  Currently, in-vehicle devices having a wireless LAN host function are widespread. In a vehicle equipped with such a vehicle-mounted device, when a portable terminal device such as a smartphone is brought into the vehicle, the smartphone can be connected to a vehicle network using the vehicle-mounted device as an access point. As a result, the in-vehicle device can stream and play content such as music and video stored in the smartphone, and the user can share and enjoy these content with other passengers.

  Patent Document 1 discloses a technology related to a navigation device that can prevent communication with an information center from being interrupted. Japanese Patent Laid-Open No. 2004-260688 grasps the radio wave situation of a mobile phone that changes under various conditions without providing a dedicated reception level determination device for measuring the reception level, and in advance when the vehicle approaches an area where the reception environment is bad The technique regarding the vehicle-mounted communication terminal device which can be notified to the passenger of this is disclosed.

JP 2000-227339 A JP 2006-157746 A

  For example, when an in-vehicle device having a host function connects a terminal device or the like that is a wireless LAN client to a network, a channel that can be satisfactorily communicated without radio wave interference is selected from a plurality of channels divided into each frequency. Wireless communication is established using the channels, and communication is possible. However, in the case of the in-vehicle device, the communication environment changes significantly because the radio wave environment moves to a different place or region as the vehicle moves. However, in the conventional in-vehicle device, once the channel is selected and connected to the terminal device, the connection state is maintained until the connection is disconnected, and even if the communication state deteriorates, the channel is changed as long as there is no instruction from the user Was not done.

  If music or video is streamed and played back between the in-vehicle device and the terminal device, the streaming playback is interrupted if the communication state deteriorates. When such a communication failure occurs, the failure can be avoided by storing and reproducing data in the buffer, but the effect is temporary.

  The present invention solves such a conventional problem and provides an in-vehicle device, a channel selection method, and a channel selection program capable of selecting an optimum channel based on radio frequency information around a travel route of a vehicle. Objective.

  The in-vehicle device according to the present invention includes communication means that enables wireless communication with a terminal device through one channel selected from a plurality of channels, and radio frequency information used in an area that provides wireless communication. Acquisition means for acquiring, selection means for selecting an optimum channel based on the acquired radio frequency information, and control means for controlling channel switching of the communication means based on the selected channel.

  Preferably, the in-vehicle device further includes a search unit that searches for a route to the destination, and the acquisition unit acquires radio frequency information around the searched route. The in-vehicle device further includes own vehicle position detecting means for detecting the own vehicle position, and the obtaining means obtains radio frequency information around the detected own vehicle position.

  Preferably, the control means does not switch the channel of the communication means when the traveling speed of the vehicle is a certain value or more. The control means includes a prediction means for predicting a time for passing through the area providing the wireless communication, and does not switch the channel of the communication means when the predicted time is equal to or less than a predetermined value. The in-vehicle device further includes a reproducing unit that performs streaming reproduction of data received from the terminal device, and the control unit performs channel switching after the data to be streamed and reproduced by the reproducing unit is buffered more than a certain amount.

  The acquisition means acquires radio frequency information used in an area where the wireless communication is provided from outside via a network. The acquisition means acquires radio frequency information used in an area providing the wireless communication stored in association with a past travel history. The selection means selects a channel that does not overlap with the radio frequency information or a channel that has the least number of overlaps.

  The in-vehicle device further includes a detection unit that detects a communication state of the communication unit, and when the decrease in the communication speed is detected by the detection unit, the selection unit selects an optimum channel.

  The channel selection method according to the present invention includes a step of wirelessly communicating with a terminal device using one channel selected from a plurality of channels, and a step of acquiring radio frequency information used in an area providing wireless communication; And a step of selecting an optimum channel based on the acquired radio frequency information, and a step of controlling channel switching in a step of performing wireless communication based on the selected channel.

  A channel selection program according to the present invention includes a step of performing wireless communication with a terminal device using one channel selected from a plurality of channels, and a step of acquiring radio frequency information used in an area providing wireless communication; And a step of selecting an optimum channel based on the acquired radio frequency information, and a step of controlling channel switching in a step of performing radio communication based on the selected channel, and are executed in the in-vehicle device.

  According to the present invention, the in-vehicle device and the terminal device can be automatically connected to another channel when the communication speed decreases while being connected through an optimal channel based on the travel route of the vehicle.

It is a figure which shows the example of 1 structure of the channel selection system of the wireless LAN which the vehicle equipment which concerns on the Example of this invention provides. It is a block diagram which shows the structure of the vehicle-mounted apparatus which concerns on the Example of this invention. It is a functional block diagram which controls communication by the control part of the vehicle-mounted apparatus in a present Example. It is the list | wrist regarding the channel information which the vehicle equipment 30 acquires. It is the schematic explaining the 1st acquisition method which acquires channel information based on a search path | route. It is the schematic explaining the 2nd acquisition method which acquires channel information based on the own vehicle position. It is an operation | movement flow explaining the operation | movement principle of the channel selection of the vehicle-mounted apparatus in the Example of this invention. It is a flowchart which shows the channel selection operation | movement at the time of a route search. It is a flowchart which shows the channel selection operation | movement at the time of a route search. It is a flowchart which shows channel selection operation | movement in case a route search is not carried out. It is a flow explaining a method for reducing the number of times of switching.

  The channel selection system of the present invention includes a terminal device that a user brings into the vehicle, and an in-vehicle device that provides a vehicle network for connecting the terminal device. Based on the radio frequency information around the position, an optimum channel that does not cause radio wave interference can be selected. The radio frequency information can be acquired from the outside through the traveling history of the host vehicle or the network. In a preferred embodiment, a channel that does not overlap with the radio frequency information is preferentially selected as the optimum channel, but when all channels overlap, the channel with the smallest number of overlaps is selected.

  Further, the in-vehicle device can detect the communication state with the connected terminal device, and when entering the area where communication failure occurs due to movement of the vehicle, it detects a decrease in the communication speed, for example, content reproduction data Can be temporarily stored in a buffer, the optimum channel can be automatically selected, and the connected channel can be switched. Thus, even during streaming playback, the playback data is not interrupted and the user can enjoy the content, and is free from troublesome work such as manually switching the connected channel.

  In a preferred aspect, the in-vehicle device has a wireless LAN function, and can be connected to a terminal device such as a smartphone as a wireless LAN access point, and streaming playback of contents such as music and video held by the connected terminal device is possible. can do.

  The in-vehicle device is generally an electronic device mounted on a vehicle and can be mounted with various functions. For example, an in-vehicle device is connected by radio, a navigation function for guiding a route to a destination, a function for reproducing audio data and video data, a function for receiving TV / radio broadcasts, a communication function for connecting to a network such as the Internet, and the like. A communication function for communicating with a terminal device can be installed.

  The in-vehicle device may store road map data for executing a navigation function itself, travel history information including radio frequency information, etc. in a storage device, or a distribution site via data communication means. Alternatively, necessary road map data or radio frequency information related to access points may be acquired from a distribution server or the like.

  In a preferred embodiment, the terminal device corresponds to a wireless LAN client and is connected to the vehicle network according to the channel selected by the in-vehicle device. In a preferred embodiment, the terminal device has a function of holding audio data and video data. For example, the terminal device is a multi-function mobile phone (smart phone), a mobile phone, a tablet PC, a mobile game machine, and other mobile phones. Type terminal.

  Next, channel selection in the in-vehicle device according to the embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a configuration example of a wireless LAN channel selection system provided by an in-vehicle device according to an embodiment of the present invention. As shown in FIG. 1A, the channel selection system 10 of this embodiment includes an in-vehicle device 30 that provides a vehicle network in the vehicle 20 and an access point when the user gets into the vehicle 20. As a smartphone 40 connected to the vehicle network.

  The in-vehicle device 30 has a wireless LAN router function for providing a vehicular network, and can wirelessly connect a terminal device, for example, a smartphone 40 within the vehicular network area. When the in-vehicle device 30 and the smartphone 40 are connected, for example, the in-vehicle device 30 can download the content held by the smartphone 40 and perform streaming reproduction.

  FIG. 1B is a schematic diagram for explaining a connection channel by a wireless LAN. The in-vehicle device 30 and the smartphone 40 are connected by a wireless LAN function, but a plurality of channels having different frequencies are prepared in order to avoid radio wave interference with other access points. The in-vehicle device 30 wirelessly connects to the smartphone 40 by selecting any one channel 50 in 1-13 ch, for example.

  The channel is a frequency band necessary for data transmission / reception, and a channel selected by the in-vehicle device 30 serving as an access point is used. The in-vehicle device 30 normally selects a so-called unused channel that is not used by a nearby access point in order to avoid radio wave interference. And select an appropriate channel.

  FIG. 2 is a block diagram illustrating a configuration of the in-vehicle device according to the embodiment of the present invention. The in-vehicle device 30 includes a position detection unit 100 that detects the position of the vehicle, a navigation unit 102 that guides a guidance route to the destination, a traffic information acquisition unit 104 that acquires road traffic information such as traffic jams and traffic restrictions, User input unit 106 that receives input, data communication unit 108 that enables data communication with the outside by wire or wireless, data reproduction / playback of music and video, road map for route guidance and guide guidance The output unit 110, a storage unit 112 for storing programs and data, an external interface (I / F) 114 that enables connection with external devices, a microcontroller, a microprocessor, and the like are executed to control each unit by executing programs. The control part 116 which comprises is comprised. In addition, this structure is an illustration, Comprising: The vehicle-mounted apparatus 30 is not limited to such a structure. The in-vehicle device 30 can be operated by a battery mounted on the vehicle even when the engine is stopped.

  The position detection unit 100 is mounted on a vehicle such as a gyro sensor or an acceleration sensor that detects the absolute position of the vehicle using a signal transmitted from a GPS satellite 136 (see FIG. 2B), for example. The relative position of the own vehicle can be detected from various sensors. In addition, the position detection unit 100 can access the position information distribution site (or distribution server) 130 via the network 120 and detect the position of the vehicle from the position information distribution site (or distribution server) 130. In this case, connection to the network 120 is performed via the data communication unit 108.

  The traffic information acquisition unit 104 acquires, for example, road traffic information superimposed on FM radio broadcasts or other broadcast waves, or receives road traffic information by radio communication from an antenna installed on a roadside such as a main road or an expressway. Can be acquired. Further, as shown in FIG. 2B, the traffic information acquisition unit 104 can access a road traffic information distribution site (or distribution server) 134 via the network 120 and acquire road traffic information therefrom. . In this case, connection to the network 120 is performed via the data communication unit 108.

  The user input unit 106 provides an interface between the user and the in-vehicle device 30. The user input unit 106 can include an input key device, a touch panel, a voice recognition device, and the like.

  The data communication unit 108 can enable wired or wireless data communication using WiFi, LAN, infrared communication, a telephone line, etc. In this embodiment, the data communication unit 108 has a wireless LAN function to The connection with the smartphone 40 brought in is enabled. In addition, the data communication unit 108 enables connection to various data distribution sites via the network 120 as shown in FIG.

  The data reproduction / output unit 110 displays a road map when guiding a guidance route to a destination, outputs music and images when content is reproduced, and a menu for making various settings of the navigation device. Includes touch panel compatible displays that display screens. The data reproduction / output unit 110 includes a speaker that outputs guidance route guidance and various warnings. In a further preferred aspect, the data playback / output unit 110 includes a buffer memory for storing streaming data when streaming data received from the smartphone 40, and adjusts the data capacity stored in the buffer memory to adjust the data capacity stored in the buffer memory. When the channel is switched between the two, the data reproduction is prevented from being interrupted.

  The storage unit 112 can store road map data and the like necessary for the operation of the in-vehicle device 30. In one example, the storage unit 112 includes a large-capacity storage device, and a database such as road map data and facility data can be stored therein. In another example, the storage unit 112 can access the road map data distribution site 132 via the network 120 as shown in FIG. 2B and acquire necessary road map data and the like therefrom. In this case, connection to the network 120 is performed via the data communication unit 108.

  In addition to the road map data, the storage unit 112 can store past travel history information. Preferably, the travel history information is an area of an access point that provides wireless communication that has passed during traveling. In such an area, an area where a communication failure has occurred, channel information used in the area, and the like are included. Note that the channel information can be acquired from the outside via the network 120.

  In a preferred embodiment, the control unit 116 includes a microcontroller including a ROM, a RAM, and the like, and the ROM or the RAM can store various programs for controlling the operation of each unit of the in-vehicle device 30. The program is received from, for example, a device that selects an optimal channel for providing a vehicle network, a device that searches for an optimal route to a destination, a device that uses a database to search for facilities, a smartphone, etc. This includes things that control data buffering.

  FIG. 3 is a block diagram illustrating a configuration of a function for controlling communication of the control unit according to the present embodiment. The control unit 116 uses the wireless LAN communication unit 140 that enables wireless LAN communication with the smartphone 40 through one channel selected from a plurality of channels, and the own vehicle based on the detected position information. Vehicle position specifying means 142 for specifying the position of the vehicle, route search means 144 for searching for a route from the specified vehicle position to the destination, and channel information used in the vicinity of the vehicle position and the searched route Channel information acquisition means 146 for acquiring the channel information, channel selection means 148 for selecting the optimum channel based on the acquired channel information, communication control means 150 for controlling the wireless LAN communication means 140 based on the selected channel, and wireless A communication state detection unit 152 that monitors a communication state of the LAN communication unit 140 and detects a decrease in communication speed. There.

  The wireless LAN communication unit 140 bears a part of the function of the data communication unit 180, can establish a communicable area with the in-vehicle device 30 as an access point, and can provide a vehicle network. At this time, the wireless LAN communication unit 140 can connect the smartphone 40 in the area by selecting one channel from a plurality of channels. When connecting a plurality of smartphones, a plurality of channels having different frequencies are used.

  The own vehicle position specifying unit 142 specifies the current position of the own vehicle based on the position information detected by the position detecting unit 100. The route searching unit 144 searches for a route from the vehicle position specified by the vehicle position specifying unit 142 to the destination.

  The channel information acquisition unit 146 can acquire channel information used at other access points provided around the search route to the destination and around the vehicle position. The channel information corresponds to radio frequency information, and the channel information may be stored in the storage unit 112 in advance, or acquired from a distribution site that distributes channel information via the network 120. You may do it. Further, based on the travel history information stored in the storage unit 112, the channel information of the access point of the area traveled in the past may be acquired.

  FIG. 4 is a list relating to channel information acquired by the channel information acquisition unit 146, and the acquired list is stored in the storage unit 112. The channel information acquisition unit 146 can acquire necessary channel information based on the searched route and the vehicle position. The list includes, for example, identification information for identifying an access point that is scattered in each region or place and provides a wireless LAN network, channel information that is a radio frequency band used by the access point, and provided by the access point. Area information indicating a network area to be transmitted and an expected transit time required to pass through the network area. In addition to this, the list may include information such as the road type of a road passing through the network area provided by the access point.

  For example, in the access point “001”, a wireless LAN network using the channel “1ch” is provided, and the network can be used within the range of “Area A”. If the vehicle 20 enters “Area A” and the wireless LAN communication means 140 uses “1ch”, radio wave interference occurs and the communication state deteriorates.

  The predicted transit time is calculated from the time required for the vehicle 20 to pass through the area, and is created from past travel history information and the predicted travel time by the navigation unit 102. For example, the estimated transit time is calculated from the start and end points of the road passing through the area C providing the access point “003” and the travel time set for the link passing through the area C. In a preferred example, the expected transit time is used to determine the effect of communication failure. If the expected transit time is smaller than a certain value, the impact is affected even if a communication failure occurs when traveling in the area. It is determined to be small. For example, in area C, the estimated passage time is “30 seconds” or less, and even if the communication speed decreases, it is determined that the influence on streaming reproduction or the like is small. In such a case, the channel information acquisition unit 146 can exclude channel information from acquisition targets according to the expected passage time. Note that the exclusion from the acquisition target is arbitrary, and the user may set the road type of the road that passes through the exclusion condition in addition to the predicted passage time.

  FIG. 5 is a schematic diagram illustrating a first acquisition method for acquiring channel information based on a searched route. When the route search unit 144 searches for the optimum route R from the current vehicle position S to the destination G, the channel information acquisition unit 146 uses the channel information of the access points AP1 and AP3 that are within a certain range E1 from the route R. To get. Since the access points AP2 and AP4 are outside the certain range E1, they are not targeted for acquisition of channel information. As described above, the channel information acquisition unit 146 acquires channel information in advance based on the travel route R to travel, and the channel selection unit 148 can select an optimum channel based on the channel information.

  FIG. 6 is a schematic view illustrating a second acquisition method for acquiring channel information based on the vehicle position. When the route search to the destination is not performed, the channel information acquisition unit 146 acquires the channel information of the access points AP6 and AP8 within the certain range E2 from the vehicle position S specified by the vehicle position specifying unit 142. To do. The channel information acquisition unit 146 acquires channel information used by access points in the vicinity of the vehicle position S in real time or at regular intervals while the vehicle 20 is traveling, and based on this channel information, the channel selection unit 148 An optimal channel can be selected.

  The channel selection unit 148 selects an optimum channel based on the channel information acquired by the channel information acquisition unit 146 as described above. In a preferred embodiment, the channel selection means 148 selects the channel that does not overlap with the acquired channel information or the channel that has the least number of overlaps among the channels 1-13 when there is no channel that does not overlap. If a channel that does not overlap with the channel information is selected, the in-vehicle device 30 can avoid radio wave interference due to the use of the same channel as the channel used by another access point. Further, when the channel with the smallest number of overlapping is selected, the in-vehicle device 30 can reduce the number of radio wave interference due to the use of the same channel.

  The communication control unit 150 can control the wireless LAN communication unit 140 based on the selected channel, determine a channel to be used, or change a currently set channel. For example, when the communication speed decreases during traveling, it is possible to automatically switch to another channel.

  The communication state detection unit 152 can monitor a change in the data communication speed between the in-vehicle device 30 and the smartphone 40 and detect a decrease in the communication speed. The communication speed to be detected can be appropriately set by the user based on, for example, a communication speed that has a sufficient margin for streaming playback.

  FIG. 7 is an operation flow for explaining the principle of the channel selection operation according to the embodiment of the present invention. First, the channel information acquisition unit 146 acquires channel information based on the searched route R and the identified own vehicle position S (S101). When using the searched route, the channel information acquisition unit 146 acquires the channel information of the access points AP1 and AP3 within the certain range E1 from the searched route R as shown in FIG. On the other hand, when the own vehicle position is used, the channel information acquisition unit 146 acquires the channel information of the access points AP6 and AP8 within the certain range E2 from the specified own vehicle position S as shown in FIG. At this time, the identification information of the access point associated with the channel information, the area information of the access point, etc. are acquired at the same time, and a list as shown in FIG. 4 is created. When channel information is acquired based on the searched route R, the estimated transit time of the area by the searched route R is calculated.

  When the channel information is acquired, the channel selection unit 148, for example, collates the acquired channel information with the channels up to 1-13ch on the vehicle-mounted device side, and determines whether there are non-overlapping channels (S102). . If all channels overlap, the channel selection unit 148 counts the number of channels 1-13ch that overlap with the acquired channel information and stores the count information (S103).

  Next, the channel selection means 148 selects an optimum channel (S104). Specifically, when there is a channel that does not overlap with the acquired channel information, one of the channels that does not overlap is selected. On the other hand, if all channels overlap, the channel with the smallest number of overlaps is selected from 1-13ch based on the count information.

  When a channel is selected, the communication control unit 150 controls the vehicle network provided by the wireless LAN communication unit 140 to use the selected channel, and the smartphone 40 is wirelessly connected through the channel. (S105). Through such a series of operations, the in-vehicle device 30 selects an optimum channel according to the travel route and the vehicle position, and suppresses the occurrence of a communication failure. However, the acquired channel information may not reflect a newly constructed network or a network in which the used channel is changed. In such a case, the wireless communication speed between the in-vehicle device 30 and the smartphone 40 decreases.

  Therefore, when the vehicle 20 is moving, the communication state detection unit 152 monitors the communication state with the smartphone 40 and detects a decrease in communication speed (S106). When a decrease in communication speed is detected, the communication control unit 152 refers to the channel information acquired in step S101 and the count information stored in step S103 (S107), and switches the channel so that the communication state is improved (S108). ). For example, in step S104, another non-selected channel is selected from non-overlapping channels and switched to the channel. Further, referring to the count information stored in step S103, the channel is switched to the channel with the next smallest number of duplicates.

  When a decrease in communication speed is detected, the control unit 116 associates information on the currently used channel and the vehicle position, stores the information in the storage unit 112 as travel history information, and subsequently reflects the information in the channel information. .

  Next, a specific channel selection operation when a route search is performed will be described. FIG. 8 is a flowchart showing a channel selection operation when a route search is performed. The channel information is acquired from an external distribution site (web site) and / or past travel history information in the storage unit 112 (S201, S202), and the in-vehicle device 30 starts a wireless LAN connection (S203). Following this start, the following channel search is executed. First, the channel selection means 148 acquires a channel (1-13ch) that can be used in the in-vehicle device 30 and the smartphone 40 (S204).

  Next, the channel selection means 148 collates the acquired channel information with 1-13ch that can be used by the in-vehicle device 30, and determines whether or not there is an overlapping channel on the search route R (S205). If there is a non-overlapping channel, the channel is then checked against the channel information of the past travel history information (S208), and if not, the channel is determined as the optimum channel (S212). For example, if “1ch” does not overlap with the channel information on the searched route R and does not overlap with the channel information of the past travel history information, “1ch” is determined as the optimum channel.

  On the other hand, when the channel overlaps with the channel information on the searched route R (S205), for example, when “1ch” overlaps, the next channel, for example, “2ch” is checked against the channel information on the searched route R. If this channel (“2ch”) does not overlap with the channel information on the searched route R, it is compared with the channel information of the past travel history information (S208), and if it does not overlap there, it is determined as the optimum channel (S212). ). If all channels (1ch to 13ch) overlap (S206), the overlapping area information (location / used channel) is stored in the memory (S207). Similarly, when the channel overlaps the channel information of the past travel history information (S208), the next channel is checked against the channel information of the past travel history information (S209). If all channels overlap, the overlapping area information (location / used channel) is stored in the memory (S210). Then, the channel with the smallest overlapping number is selected (S211). Through the above channel search, the optimum channel used by the in-vehicle device 30 is determined (S212).

  The in-vehicle device 30 wirelessly connects the smartphone 40 based on the determined channel. Thereafter, when the vehicle enters the access point area (hereinafter referred to as an overlapping area) that uses a channel that overlaps the channel used by the in-vehicle device 30 as the vehicle travels (S213), it is stored in the memory in steps S207 and S210. It is determined whether or not there is any information corresponding to the stored overlapping area information (S214), and if there is a corresponding area, the channel used in the overlapping area is known, so that there is no other overlapping information. The channel is automatically switched to (S217). When the data received from the smartphone 40 is streamed and played back on the in-vehicle device 30, the channel change is performed almost in real time, and thus the data buffering is not performed in the in-vehicle device 30.

  On the other hand, if there is no data corresponding to the overlapping area information stored in the memory, the in-vehicle device 30 performs buffering so as to accumulate a certain amount of data during streaming reproduction (S215), and then the channel in the background. A search is performed (S216). By making the amount of data to be buffered larger than the amount of data reproduced during the time required for the channel search, the data reproduction can be prevented from being interrupted. Then, the channel selection means 148 selects the channel with the smallest overlapping number and switches to this channel (S217).

  Next, another specific channel selection operation will be described. FIG. 9 is a flow diagram illustrating the channel selection operation when preferably no route search is performed. First, the channel information is acquired from the distribution site and / or the storage unit 112 (S301, S302), and the in-vehicle device 30 starts a wireless LAN connection (S303). Here, the overlapping area information is stored in the memory based on the acquired channel information (S304). Here, since the amount of data becomes enormous when storing information such as channels, only the location is stored in the memory. Next, the channel selection means 148 selects a channel that does not overlap by channel search and determines a channel (S305).

  The in-vehicle device 30 wirelessly connects the smartphone 40 based on the determined channel. Thereafter, when the channel to be used enters an overlapping area as the vehicle travels (S306), the playback data being streamed is buffered so that playback is not interrupted (S307), and then the channel search is performed in the background. (S308). The channel search refers to the overlapping area information stored in the memory in step S304, and switches to a non-overlapping channel (S309). Note that the flow of FIG. 9 may be performed when a route search is performed.

  FIG. 10 is a flow for explaining a preferred method for reducing the number of times of switching in the channel selection operation. When the vehicle 20 enters an area that uses a channel that overlaps the channel used by the vehicle 20 (S401), the control unit 116 detects the traveling speed of the host vehicle via the external I / F 114 (S402). Then, the control unit 116 determines whether or not the detected traveling speed is equal to or higher than a certain level (S403). For example, when the traveling speed is equal to or higher than a certain speed, such as 80 km / h, the communication control unit 150 does not perform channel switching because it is expected that the vehicle immediately passes through the overlapping area (S404). On the other hand, when the traveling speed does not satisfy the constant speed, the communication control unit 150 performs channel switching (S405). In this case, as in steps S214, S215, and S216 shown in FIG. 8B, when the overlapping area is stored in the memory, the channel is switched to a non-overlapping channel. The channel search is performed after ringing, and the channel is switched to another channel.

  As a modification of the example shown in FIG. 10, the channel selection unit 148 determines whether or not the predicted passage time shown in FIG. 4 is equal to or greater than a certain value. Therefore, the channel may be switched when a predetermined value is exceeded without switching the channel.

  Further, in the present embodiment, the channel selection unit 148 may select an optimum channel when the communication state detection unit 152 shown in FIG. 3 detects that the communication speed is below a certain level. Since one of the causes of the decrease in the communication speed is considered to be radio wave interference, the channel search as shown in FIG. 8 or FIG. 9 is executed by using the decrease in the communication speed as a trigger, and the optimum channel is selected.

  Thus, the in-vehicle device in the embodiment of the present invention can reduce the number of times of channel switching according to the traveling speed of the vehicle. In the embodiment described above, the traveling speed of the vehicle is used as a condition. However, the number of times of channel switching may be reduced according to the type of road on which the vehicle travels (such as an expressway).

  In the above embodiment, a channel that does not cause radio wave interference or a channel that has a low frequency of radio wave interference is selected based on the search route to the destination and the channel information around the vehicle position. In addition, when a vehicle moves and enters a channel overlap area where radio wave interference occurs, the optimum channel can be automatically selected and the channel to be connected can be switched. Thus, even during streaming playback, the user can enjoy the content without interrupting the playback data, and is freed from troublesome work such as manually switching the connected channel.

  The present invention is not limited to the above embodiments, and various modifications and changes can be made within the scope of the gist of the invention described in the claims. In addition, the present invention can include carrying out the first or second embodiment individually or in combination.

DESCRIPTION OF SYMBOLS 10: Channel switching system 20: Vehicle 30: In-vehicle apparatus 40: Smartphone 50: Channel 100: Position detection part 102: Navigation part 104: Traffic information acquisition part 106: User input part 108: Data communication part 110: Output part 112: Storage Unit 114: external interface 116: control unit 120: network 140: wireless LAN communication unit 142: own vehicle position specifying unit 144: route search unit 146: channel information acquisition unit 148: channel selection unit 150: communication control unit 152: communication state Detection means

Claims (12)

A communication means for enabling wireless communication with a terminal device through one channel selected from a plurality of channels;
Acquisition means for acquiring radio frequency information used in an area providing wireless communication;
Selection means for selecting an optimum channel based on the acquired radio frequency information;
Control means for controlling channel switching of the communication means based on the selected channel;
In-vehicle device having The in-vehicle device according to claim 1, further comprising search means for searching for a route to a destination, wherein the acquiring means acquires radio frequency information around the searched route. The in-vehicle device according to claim 1, wherein the in-vehicle device further includes own vehicle position detecting means for detecting the own vehicle position, and the acquiring means acquires radio frequency information around the detected own vehicle position. The in-vehicle device according to claim 1, wherein the control unit does not switch a channel of the communication unit when a traveling speed of the vehicle is equal to or higher than a certain value. The control unit includes a prediction unit that predicts a time for passing through the area that provides the wireless communication, and does not switch a channel of the communication unit when the predicted time is equal to or less than a predetermined value. The vehicle-mounted device as described in one. The in-vehicle device further includes a reproducing unit that performs streaming reproduction of data received from the terminal device, and the control unit performs channel switching after the data to be streamed and reproduced by the reproducing unit is buffered more than a certain amount. The in-vehicle device according to Item 1. The in-vehicle device according to claim 1, wherein the acquisition unit acquires radio frequency information used in an area where the wireless communication is provided from outside via a network. The in-vehicle device according to any one of claims 1 to 6, wherein the acquisition unit acquires radio frequency information used in an area providing the wireless communication stored in association with a past travel history. The in-vehicle device according to any one of claims 1 to 8, wherein the selection unit selects a channel that does not overlap with the radio frequency information or a channel with the smallest number of times of overlapping. The in-vehicle device further includes a detection unit that detects a communication state of the communication unit, and the selection unit selects an optimum channel when a decrease in communication speed is detected by the detection unit. The vehicle-mounted apparatus as described in one. Wirelessly communicating with the terminal device through one channel selected from a plurality of channels;
Obtaining radio frequency information used in an area providing wireless communication;
Selecting an optimal channel based on the acquired radio frequency information;
Controlling channel switching in a step of performing wireless communication based on the selected channel;
A channel selection method comprising: Wirelessly communicating with the terminal device through one channel selected from a plurality of channels;
Obtaining radio frequency information used in an area providing wireless communication;
Selecting an optimal channel based on the acquired radio frequency information;
Controlling channel switching in a step of performing wireless communication based on the selected channel;
A channel selection program executed in an in-vehicle device.

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