JP2006262177A - In-vehicle wireless lan apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an in-vehicle wireless LAN apparatus for suppressing wasteful power consumption caused by search operation or the like for a wireless LAN access point. <P>SOLUTION: A wireless LAN module 30 is first brought into a standby state (S401), a perimeter access point list is read (S402), and the presence of wireless LAN access points is confirmed (S403). When an available wireless LAN access point exists around the present position (Y in S403), the wireless LAN module is started (S404) and thereafter the available wireless LAN access point at a present point of time is particularized. Then the in-vehicle wireless LAN apparatus selects the wireless LAN access point to be network-connected, and tries the network connection to the wireless LAN access point (S408). After the connection is established, the wireless LAN apparatus controls a radio wave output and its directivity of the wireless LAN module 30 (S409) while monitoring a distance to the wireless LAN access point 20 and the direction of the wireless LAN access point 20. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vehicle-mounted wireless LAN device, and more particularly to a wireless LAN device that can be interlocked with a car navigation device.

  In recent years, wireless LAN has been widely used as one of means for connecting to the Internet. A wireless LAN is a form of LAN that can form a network without using a cable. The standardization of the wireless LAN has been advanced with IEEE 802.11, and at present, 802.11b, which can communicate at a maximum of 11 Mbps using a 2.4 GHz band radio wave, and a maximum of 54 Mbps using a 2.4 GHz band radio wave. There are three standards: 802.11g, which allows communication of up to 54 Mbps using a 5.2 GHz band radio wave. If a wireless LAN system is constructed using network equipment compliant with these standards, anyone can easily construct a wireless LAN. For example, by connecting to a wireless base station called an access point from a notebook computer on which a wireless LAN module is mounted, it is possible to connect to the Internet without a cable connection. Recently, it is possible to connect not only to a personal wireless LAN access point installed at home but also to a public access point installed outdoors or a paid access point provided by a provider.

Furthermore, recently, various attempts have been made to download a variety of information while moving in a vehicle by mounting a wireless LAN system on the vehicle. For example, Japanese Patent Application Laid-Open No. 2004-212338 discloses an example where a wireless LAN module is mounted on a vehicle. In this example, if the car navigation device connects to the Internet via a mobile phone, while searching for a wireless LAN access point that can be connected by the wireless LAN module, and there is a wireless LAN access point that can be connected, The communication means is switched from the mobile phone to the wireless LAN module.
JP 2004-212338 A

  However, in the conventional method as described above, whether or not a connectable wireless LAN access point exists is always searched, and the wireless LAN module outputs a radio wave called a probe to respond from the wireless LAN access point. Therefore, there is a problem that power is wasted. In particular, since wireless LAN access points can be freely installed by anyone without being restricted by the Radio Law, the communication areas of wireless LAN access points called “wireless spots” are scattered randomly and overcrowded with wireless spots. There are zones and blank zones. Therefore, in the conventional method, there is a possibility that a situation in which a search operation is executed even when there is no wireless LAN access point around the current position may occur frequently, and if wasteful power consumption is also integrated. Expected to be enormous. Furthermore, even after connecting to a wireless LAN access point, the vehicle is running and the communication status is constantly changing. Therefore, a method of communicating more efficiently without consuming unnecessary power is desired. .

  Accordingly, an object of the present invention is to suppress wasteful power consumption due to a search operation of a wireless LAN access point or the like in an in-vehicle wireless LAN device that can be interlocked with a car navigation device.

  An object of the present invention is an in-vehicle wireless LAN device that can be linked to a car navigation device that can identify the current position of a vehicle, a wireless communication module that connects to a wireless base station, and a position of the wireless base station This is achieved by a vehicle-mounted wireless LAN device comprising control means for controlling the output of the wireless communication module based on the information and the current position information of the vehicle.

  In the present invention, the control means may switch the wireless communication module in an operating state to a non-operating state in response to determining that there is no connectable wireless base station around the current position of the vehicle. preferable.

  Further, in the present invention, the control means switches the wireless communication module in a non-operating state to an operating state in response to determining that there is a connectable wireless base station around the current position of the vehicle. Is preferred.

  In the present invention, the wireless communication module is activated to detect a wireless base station, a desired wireless base station is selected from the detected wireless base stations and connected, and the position information of the wireless base station Preferably, the output intensity of the wireless communication module is adjusted based on the current position information of the vehicle.

  In the present invention, the wireless communication module is activated to detect a wireless base station, a desired wireless base station is selected from the detected wireless base stations and connected, and the position information of the wireless base station It is preferable to control the directivity of the antenna of the wireless communication module based on the current position information of the vehicle.

  In the present invention, it is preferable to further comprise storage means for storing position information of the radio base station.

  According to the present invention, in a wireless LAN device that can be linked to a car navigation device, when connecting to a wireless base station that is in the middle of a vehicle and performing communication, useless power consumption due to a search operation of the wireless base station, etc. Can be suppressed.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a diagram showing a configuration of a wireless LAN system according to a preferred embodiment of the present invention.

  As shown in FIG. 1, the wireless LAN system 1 includes a wireless LAN access point 10 installed at an arbitrary place and an in-vehicle wireless LAN device 20 mounted on a vehicle X.

  The wireless LAN access point 10 is a network device that forms a wireless network and relays between the wireless network and the wired network. The wireless LAN access point 10 includes a wireless LAN module, and has various functions such as a router function, a firewall function, an encryption communication function, a user authentication function, and a file server function like a network device called a wireless LAN router. There are many things. The wireless LAN access point 10 of the present embodiment is connected to the Internet 2, and is connected to the content provider 3, the road traffic information center 4, and the like via the Internet 2.

  On the other hand, the wireless LAN device 20 has a function of interlocking with the car navigation device. As is well known, the car navigation device is a device that presents the current position of the vehicle X based on position information from the GPS, and further guides the route of the vehicle X to a desired destination. Although details will be described later, the car navigation device of the present embodiment has map information such as roads, buildings, stores, and landscapes. The map information is recorded in a recording means such as a DVD-ROM or a hard disk drive, and after being read and processed in the car navigation device, it is displayed on the display as a route guidance screen to the destination, and from the speaker as voice guidance. Is output.

  FIG. 2 is a diagram showing a configuration of the wireless LAN device 20 including the car navigation device.

  As shown in FIG. 2, the wireless LAN device 20 includes a system MPU 21 that performs various arithmetic processes by executing predetermined programs, and distances and distances between the vehicle and the GPS satellites that receive signals from the GPS satellites. GPS receiver 22 that measures the rate of change of the vehicle, various sensors 23 such as a gyro sensor 23a and a vehicle speed pulse sensor 23b that measure the running state of the vehicle, and a hard disk drive (HDD) 24a and DVD-ROM in which map information and the like are recorded A recording medium 24 such as a drive 24b, a display 26 connected via an image processing unit 25, a microphone 28a and a speaker 28b connected via an audio processing unit 27, a control panel 29 serving as an input interface, and the above-mentioned Wireless LAN module for connecting to the wireless LAN access point 10 0 is composed of a.

  The system MPU 21 executes a predetermined program and is used for various calculations. For example, the current position of the vehicle X is calculated based on information from the GPS receiver 22 and various sensors 23. The measurement result of the GPS receiver 22 is input to the system MPU 21 together with the measurement results of the gyro sensor 23a and the vehicle speed pulse sensor 23b. The system MPU 21 calculates these to calculate the current position and traveling direction of the vehicle X. Based on the current position of the vehicle X calculated in this manner, map information around the vehicle X is read from the hard disk drive 24a or DVD-ROM 24b, and the current position of the vehicle X is displayed on the display 26 so as to be superimposed on the map information. Is done. When route guidance to the destination is being performed, a landscape is displayed on the display 26 at a corner or other point where attention should be paid, and voice guidance is output from the speaker 28b. Necessary operations such as map operation and destination setting are performed by voice input to the control panel 29 and the microphone 28a.

  In addition to the above-described map information, the wireless LAN device 20 holds, as a database, location information of the wireless LAN access point 10 and information necessary for connection to the wireless LAN access point 10 called a profile. It is recorded on the DVD-ROM 24b. These pieces of information are used when connecting to the wireless LAN access point 10. The location information of the wireless LAN access point may or may not be displayed on the display 26 together with the map information as necessary. Furthermore, such display / non-display may be freely switched.

  The wireless LAN module 30 is a communication module for wirelessly connecting to the access point 10. The wireless LAN module 30 is mounted in common with the wireless LAN access point 10 and the wireless LAN device 20, but there are various forms such as a PCMCIA card type, a USB stick type, a PCI board type, and an onboard type. . By connecting the wireless LAN device 20 and the wireless LAN access point 10 via the wireless LAN module 30, for example, the wireless LAN device 20 accesses the content provider 3 or the road traffic information center 4 on the Internet 2 to It is possible to download information such as information, music files, video files, and HTML documents.

  FIG. 3 is a block diagram schematically showing the configuration of the wireless LAN module 30.

  As shown in FIG. 3, the wireless LAN module 30 includes a bus interface (I / F) 31 for connection to the access point body or the wireless LAN apparatus body, and a MAC that performs access control such as packet processing and CSMA / CA. A (Media Access Control) unit 32; a BB (Base Band) unit 33 that performs primary modulation by a PSK (Phase Shift Keying) modulation method, a CCK (Complementary Code Keying) modulation method, and secondary modulation by a spread spectrum communication method; An RF unit 34 that performs RF processing of a signal, an antenna 35, a controller 36 that controls each unit, and a memory 37 that stores firmware and data such as a MAC address for executing a predetermined communication protocol are provided.

  As the antenna 35, an antenna whose directivity can be controlled is used. When the directivity is mechanically controlled, for example, the antenna 35 is mounted on a rotary table using a motor or the like as a drive source, and the direction of the antenna 35 is changed under the control of the controller 36. When the directivity is electrically controlled, the directivity of the antenna 35 is changed by a control signal from the controller 36 using a phased array antenna.

  The signal received by the antenna 35 is reproduced as an original packet processed in the order of the RF unit 34, the BB unit 33, and the MAC unit 32, and transferred to the access point main unit side or the wireless LAN device main unit side via the bus interface 31. The At the time of packet transmission, a transmission packet is input via the bus interface 31, and then processed in the order of the MAC unit 32, the BB unit 33, and the RF unit 34, and transmitted from the antenna 35 as a radio wave. In the wireless LAN device 20, when searching for a connectable access point, a beacon signal broadcast from the access point is received by the RF unit 34, and an SSID (Service Set Identifier) of the access point is acquired. The received signal strength (RSSI) is measured. The acquired SSID and received signal strength are transferred to the wireless LAN device main body side via the bus interface 31.

  The wireless LAN device 20 having the above configuration establishes a network connection with the wireless LAN access point 10 to perform communication. At this time, the wireless LAN device 20 performs wireless LAN access according to the following procedure. Connect to point 10.

  FIG. 4 is a flowchart showing a connection procedure to a wireless LAN access point.

  As shown in FIG. 4, the wireless LAN device 20 first sets the wireless LAN module 30 to a standby state (non-operating state) (S401), and then determines the wireless LAN access point existing around the current position of the vehicle. The list (peripheral access point list) is read (S402), and the presence of the wireless LAN access point is confirmed (S403). Although details will be described later, the peripheral access point list is created and held in advance by the wireless LAN device 20, and is regularly updated to the latest information.

  FIG. 5 is a diagram showing an example of a peripheral access point list. In this example, “No.”, “SSID”, “location information” and “profile” of the wireless LAN access point are shown. An SSID (Service Set Identifier) is an ID used to identify a network and plays a role of logically grouping the networks. Recently, ESSID (Extended Service Set Identifier) may be used instead of SSID. Further, as described above, the profile is a setting file including information necessary for connection to the wireless LAN access point, and includes, for example, a MAC address, an encryption method, and an encryption key thereof. Examples of the encryption method include WEP, TKIP, and AES.

  Next, when an available wireless LAN access point exists in the vicinity of the current position (S403Y), after starting the wireless LAN module (S404), in order to identify the currently available wireless LAN access point The received signal strength (RSSI) of the beacon broadcast from the wireless LAN access point is searched (S405), and an RSSI list of wireless LAN access points existing around the current position of the vehicle is created (S406). ).

  FIG. 6 is a diagram illustrating an example of the RSSI list. Information included in the detected beacon is registered in the RSSI list. In this example, “list No.”, “SSID”, and “RSSI” are shown. Note that an SSID (Service Set Identifier) is an ID used for network identification, and plays a role in logically grouping wireless LAN networks. Recently, ESSID (Extended Service Set Identifier) may be used instead of SSID.

  Next, using this RSSI list, the wireless LAN access points in the peripheral access point list are filtered (S407). The RSSI list is a list of wireless LAN access points that are actually operating, but the peripheral access point list is only a list on the database, and a wireless LAN access point actually exists at that position, or a wireless LAN access point list. It is unknown whether the access point is actually operating. Therefore, by superimposing the peripheral access point list and the RSSI list, only wireless LAN access points that can actually be connected are listed. Then, a wireless LAN access point to be connected to the network is selected from the filtered peripheral access point list, and network connection is attempted to the wireless LAN access point (S408).

  After the connection is established, the radio wave output and directivity of the wireless LAN module 30 are controlled while monitoring the distance to the wireless LAN access point 20 and the direction of the wireless LAN access point 20 (S409). Specifically, since the position information of the wireless LAN access point 20 and the distance from the current position of the vehicle X to the wireless LAN access point 20 can be known, the wireless LAN module is used when the distance to the wireless LAN access point 20 is long. The radio wave output of 30 is increased, and the radio wave output is lowered when it is close to always maintain the optimal radio wave output. Further, since the direction of the wireless LAN access point 20 can be known from the position information of the wireless LAN access point 20 and the current position of the vehicle X, the antenna 35 of the wireless LAN module 30 is controlled mechanically or electrically to control the direction. To match the direction of the wireless LAN access point 20. After that, when it becomes difficult to maintain the connection due to a decrease in throughput or the like, the above-described series of connection procedures is started again (S410Y, S401-S409).

  FIG. 7 is a flowchart showing a procedure for creating (updating) a peripheral access point list.

  As shown in FIG. 7, the wireless LAN device 20 first receives GPS data (S801), processes the GPS data together with the output results of various sensors, and calculates the exact position of the vehicle (S802). Next, based on the position information of the own vehicle obtained in this way, the wireless LAN device 20 uses the wireless LAN around the current position of the own vehicle from a database in which information of all wireless LAN access points is recorded. By listing the access points (S803), the peripheral access point list shown in FIG. 7 is created (S804). By periodically repeating the above steps, the peripheral access point list is updated and the latest state is maintained. By referring to this peripheral access point when selecting a wireless LAN access point, a connectable wireless LAN access point can be quickly selected.

  As described above, according to the present embodiment, in a wireless LAN device having a function of interlocking with a car navigation device, when communication is performed by connecting to a wireless LAN access point that exists in the middle of traveling of the vehicle, Referring to the database in which the location information of the LAN access point is recorded, it is checked in advance whether or not there is a wireless LAN access point around the current location of the vehicle. In this case, since the wireless LAN module is activated and the search for the wireless LAN access point is executed, useless power consumption due to the search operation for the wireless LAN access point can be suppressed.

  Further, according to the present embodiment, the position information of the wireless LAN access point and the distance to the wireless LAN access point obtained from the current position of the vehicle are monitored, and the radio wave output of the wireless LAN module is the distance to the wireless LAN access point. Therefore, the power consumption by the wireless LAN module can be reduced while maintaining the communication quality at a certain level.

  Furthermore, according to the present embodiment, the direction of the wireless LAN access point obtained from the position information of the wireless LAN access point and the current position of the vehicle is monitored, and the directivity of the antenna of the wireless LAN module is set to the direction of the wireless LAN access point. Therefore, the power consumption by the wireless LAN module can be reduced while maintaining the communication quality at a certain level.

  The present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention, and these are also included in the scope of the present invention. Needless to say.

  For example, in the above embodiment, a wireless LAN device including a car navigation device has been described. However, the present invention is not limited to this, and for example, an in-vehicle computer mounted with a wireless LAN module is a car navigation device. It is also possible to prepare the present invention separately and realize the present invention by linking the in-vehicle computer and the car navigation device. The wireless LAN device of the above embodiment can also be regarded as an in-vehicle computer having both a car navigation function and a wireless LAN function, or a car navigation device having a wireless LAN function. That is, the present invention can take various forms as long as the wireless LAN function and the car navigation function are linked.

FIG. 1 is a diagram showing a configuration of a wireless network system according to a preferred embodiment of the present invention. FIG. 2 is a diagram illustrating a configuration of the wireless LAN device 20. FIG. 3 is a block diagram schematically showing the configuration of the wireless LAN module 30. FIG. 4 is a flowchart showing a connection procedure to a wireless LAN access point. FIG. 5 is a diagram showing an example of a peripheral access point list. FIG. 6 is a diagram illustrating an example of the RSSI list. FIG. 7 is a flowchart showing a procedure for creating (updating) a peripheral access point list.

Explanation of symbols

1 Wireless Network System 2 Internet 3 Content Provider 4 Road Traffic Information Center 10 Wireless LAN Access Point 20 Wireless LAN Device 21 System MPU
22 GPS receiver 23 Various sensors 23a Gyro sensor 23b Vehicle speed pulse sensor 24 Recording medium 24a Hard disk drive 24b DVD-ROM
25 Image processing unit 26 Display 27 Audio processing unit 28a Microphone 28b Speaker 29 Control panel 30 Wireless LAN module 31 Bus interface 32 MAC unit 33 BB unit 34 RF unit 35 Antenna 36 Controller 37 Memory X Vehicle

Claims (6)

An in-vehicle wireless LAN device that can be linked to a car navigation device that can identify the current position of a vehicle,
A wireless communication module for connecting to a wireless base station;
An in-vehicle wireless LAN device comprising: means for controlling an output of the wireless communication module based on position information of the wireless base station and current position information of the vehicle.   The control means switches the wireless communication module in an operating state to a non-operating state in response to determining that there is no wireless base station that can be connected around the current position of the vehicle. Item 2. The in-vehicle wireless LAN device according to Item 1.   The said control means switches the said radio | wireless communication module in a non-operation state to an operation state in response to having determined that the radio base station which can be connected exists around the present position of the said vehicle. The in-vehicle wireless LAN device according to 1 or 2.   Activating the radio communication module to detect a radio base station, selecting and connecting a desired radio base station from the detected radio base stations, and position information of the radio base station and the current vehicle The in-vehicle wireless LAN device according to any one of claims 1 to 3, wherein an output intensity of the wireless communication module is adjusted based on position information.   Activating the radio communication module to detect a radio base station, selecting and connecting a desired radio base station from the detected radio base stations, and position information of the radio base station and the current vehicle 5. The in-vehicle wireless LAN device according to claim 1, wherein directivity of an antenna of the wireless communication module is controlled based on position information. The in-vehicle wireless LAN device according to any one of claims 1 to 5, further comprising storage means for storing location information of the wireless base station.

Images