JP2009194482A - Radio network connection switching method by monitoring communication state, and apparatus thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio network connection switching method by monitoring a communication state, capable of rapidly connecting an apparatus to a radio connection point during moving to perform communication, and to provide an apparatus thereof. <P>SOLUTION: The radio network connection switching apparatus 10 has a ping packet transmission/reception section 12, a DHCP packet transmission/reception section 14 and an IP address control section 16. The ping packet transmission/reception section 12 repeats a transmitting ping to a radio connection point and receiving a ping response from a radio connection point responding to the ping, thereby always confirming the connection state between itself and the radio connection point. When the ping packet transmission/reception section 12 becomes a state not receiving the ping response, the DHCP packet transmission/reception section 14 searches the radio connection point. Further, upon receiving a response from a radio connection point connectable by search of the DHCP packet transmission/reception section 14, the IP address control section 16 acquires an IP address from the radio connection point. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a wireless network connection switching method and apparatus based on communication state monitoring when connecting to a wireless network while moving.

  A terminal performs wireless communication by connecting to an access point from this terminal. Since wireless communication access points have a limited communication range (communication area), in order to perform wireless communication while a terminal mounted on a vehicle or the like moves, it is necessary to switch to a different access point and connect. .

  By the way, in the invention described in Patent Document 1, when a mobile terminal moves and enters a different basic service set (BSS), when a handover process for automatically switching to an access point of the different BSS is performed, the mobile terminal The provided detection unit detects that the BSS has been changed. When a change in an extended service set (ESS) combining a plurality of BSSs is not detected, the mobile terminal sends a DHCP Discover to a DHCP (Dynamic Host Configuration Protocol) server to inquire about subnet information. Then, since DHCP Offer is transmitted from the DHCP server to the mobile terminal, the mobile terminal compares the subnet information included in the DHCP Offer with the subnet information before the handover, and determines whether the subnet is different before and after the handover. To do. If the subnet is different in this determination, the mobile terminal performs a process of sending a DHCP request to the DHCP server and receiving a DHCP ACK from the DHCP server, thereby obtaining a new IP (Internet Protocol) address from the DHCP server. Obtained, connected to the Internet with this new IP address, and resumed data communication.

If the mobile terminal detects a change in the ESS, the mobile terminal disconnects the data communication, inquires about the subnet information to the DHCP server, and in response to the inquiry, the subnet information sent from the DHCP server, the subnet information before the handover, To determine whether the subnet is different before and after the handover. If the subnets are different in this determination, the mobile terminal acquires a new IP address from the DHCP server, connects to the Internet using the new IP address, and resumes data communication.
Japanese Patent Laying-Open No. 2005-1224087 (see especially pages 5-6)

  The basic usage of personal computers is to turn on the power in a communication area where a wireless LAN (Local Area Network) can be used. That is, the wireless LAN of a personal computer does not consider use while moving. For this reason, when trying to perform wireless communication while moving a personal computer equipped with a wireless LAN card, when the personal computer enters the communication area, the wireless LAN card receives wireless radio waves from the access point and connects to the access point. Processing is in progress.

  However, in a network under a DHCP environment such as a public wireless LAN service, data communication cannot be started unless an IP address acquisition process by DHCP is performed. In the wireless network connection mechanism installed in the conventional personal computer, the connection process with the access point and the IP address acquisition process by DHCP are not well linked. That is, since the part for switching between different communication areas and the part for controlling the IP address (DHCP request) are different, the two are not linked well. For this reason, it may take time until the IP address acquisition processing by DHCP is started after the connection processing with the access point is completed.

  Usually, switching of access points caused by movement of a vehicle equipped with a terminal such as a personal computer and setting of an IP address by DHCP depend on a driver of the network interface. Even in the invention described in Patent Document 1 described above, detection of access point switching depends on the driver of the wireless interface portion. In other words, when a mobile terminal enters a wireless communication area and performs wireless connection processing with an access point, the time until wireless communication is detected and communication is possible depends on the type of wireless LAN card and the type of wireless LAN connection tool. Will depend on. As described above, in the prior art, since processing is performed inside the personal computer and inside the wireless LAN card, it is difficult to change or modify the personal computer.

  For this reason, as shown in FIG. 4, even if the vehicle 1 equipped with the terminal enters the communication area 2, it takes time until the terminal and the access point 3 start processing for wireless connection, and wireless communication is possible. Then, the vehicle 1 is about to leave the communication area 2, so that the communicable time is shortened, or the vehicle 1 leaves the communication area 2 without communication between the terminal and the access point 3 ( Will pass without communication). Further, when the communicable time is short, the connection is made at the peripheral edge of the communication area 2, so the radio wave intensity of the communication becomes weak and stable wireless communication cannot be performed.

  An object of the present invention is to provide a wireless network connection switching method and apparatus based on a communication state monitoring capable of quickly connecting to a wireless connection point during communication and performing communication.

  The wireless network connection switching method by communication state monitoring according to the present invention outputs a connection confirmation signal from a mobile body to a wireless connection point and repeatedly receives a response from the wireless connection point to the mobile body, It is characterized in that if the connection between the mobile body and the wireless connection point is continuously confirmed and no response is received from the wireless connection point, a search signal for the wireless connection point is repeatedly output from the mobile body.

  The wireless network connection switching method by communication state monitoring according to the present invention repeatedly outputs a search signal for a wireless connection point from a mobile body, and when the mobile body receives a response to the search signal from the wireless connection point, It is characterized in that communication with a connection point is made possible and the establishment state of communication between the mobile unit and the wireless connection point is continuously checked.

  In these cases, in the wireless network connection switching method by communication state monitoring, the connection confirmation signal is ping, the response for confirming the communication establishment state between the mobile unit and the wireless connection point is a ping response, and the search signal Is a DHCP Discover packet, and a response to the search signal may be a DHCP Offer response.

  Furthermore, the wireless network connection switching method based on the communication state monitoring can be configured such that the mobile body wirelessly connects to an access point arranged in the network as the wireless connection point.

  The wireless network connection switching apparatus according to the present invention for monitoring the communication state transmits a ping to a wireless connection point, and repeatedly receives a ping response from the wireless connection point responding thereto, to and from the wireless connection point. The ping packet transmission / reception unit that continues to check the connection state in the connection, and when the ping packet transmission / reception unit does not receive the ping response, the DHCP packet transmission / reception unit that searches for the wireless connection point is connected by the search of the DHCP packet transmission / reception unit And an IP address control unit that obtains an IP address from the wireless connection point when there is a reply from the wireless connection point.

  Since the wireless network connection switching method and apparatus based on the communication state monitoring constantly monitors the connection of communication with the wireless connection point, it is possible to search for a wireless connection point that can be immediately communicated when communication cannot be performed. When searching for a new wireless connection point, since the search signal is repeatedly output, the mobile signal enters the communication area, and as soon as the wireless connection between the mobile unit (terminal) and the wireless connection point is established, the search signal is DHCP. Will be entered into the server. Therefore, since the IP address acquisition process can be started immediately after the connection process to the wireless connection point is completed, the IP address can be quickly given and data communication can be performed. Note that DHCP is used for these processes.

  As a result, the time from entering the communication area until communication with the wireless connection point can be shortened. Even when the mobile unit is connected to the network, it can be reliably connected to a network that can communicate with the movement of the mobile unit.

  The best mode of the wireless network connection switching method and apparatus according to the present invention will be described below. FIG. 1 is a block diagram illustrating a configuration of a wireless network connection switching device. FIG. 2 is a block diagram illustrating the wireless network connection of the terminal. As shown in FIG. 2, the wireless network connection switching device 10 is connected while a terminal 26 such as a personal computer is connected to a wireless connection point 32 in a communication area such as a wireless LAN or a WAN (Wide Area Network). The connection state with the default gateway 22 in the network is constantly monitored. When it is determined that communication is difficult, a new wireless connection point 32 is searched, and when it is found, the network interface setting is immediately opened / reset. Such a wireless network connection switching device 10 is mounted on the terminal 26 together with the wireless communication control unit 28 and can be moved, or can be connected to the terminal 26 including the wireless communication control unit 28 and moved. I'm going. Therefore, the wireless network connection switching device 10 is mounted on the vehicle 30 (see FIG. 3) together with the terminal 26 and is a movable body that can be moved, or can be a portable body that can be carried along with the terminal 26 by a person.

  The wireless communication control unit 28 may be a network interface or the like for connecting to the wireless connection point 32. As a more specific example, the wireless communication control unit 28 may be a wireless LAN card or the like. The wireless LAN card may be a standard installed in a personal computer or the like, or may be a high-performance wireless LAN interface that can quickly start connection processing with the wireless connection point 32. This high-performance wireless LAN interface is a function for measuring the radio wave intensity from the radio connection point 32 and searching for other radio connection points 32 having a strong radio wave intensity in the vicinity when the threshold value is set below. have.

  The wireless network connection switching apparatus 10 includes a ping packet transmission / reception unit 12, a DHCP packet transmission / reception unit 14, and an IP address control unit 16 as shown in FIG.

  The ping packet transmission / reception unit 12 performs wireless communication with the wireless connection point 32 arranged in the communication area, and outputs a connection confirmation signal and receives a response from the wireless connection point 32. The wireless communication connection between the mobile unit and the wireless connection point 32 is constantly monitored. The wireless connection point 32 may be the default gateway 22 or an access point. In the case illustrated in FIG. 1, the ping packet transmission / reception unit 12 performs wireless communication with the default gateway 22.

  The DHCP packet transmission / reception unit 14 is connected to the ping packet transmission / reception unit 12 and can perform wireless communication with the DHCP server 24. When it is determined that wireless communication between the mobile unit and the wireless connection point 32 is difficult, the DHCP packet transmitting / receiving unit 14 generates a signal (search signal) for searching for a new communication area in which wireless communication can be performed with the mobile unit. A response to the search signal from the wireless connection point 32 in the communicable communication area is output.

  Further, the IP address control unit 16 has an IP address releasing unit 18 connected to the DHCP packet transmitting / receiving unit 14 and an IP address obtaining unit 20 connected to the IP address releasing unit 18. The IP address controller 16 uses the IP address release means 18 and the IP address acquisition means 20 to immediately release / reset the network interface settings when a new wireless connection point 32 is found. In other words, the IP address control unit 16 acquires a new IP address from the DHCP server 24.

  Next, a wireless network connection switching method using such a device 10 will be described with reference to FIGS. FIG. 3 is a diagram for explaining the relationship between the wireless network connection switching device and the communication area. In the case shown in FIG. 3, the vehicle 30 equipped with the wireless network connection switching device 10 is moving from the left side to the right side in this figure, and the mobile body first performs wireless communication with the wireless connection point 32 a. . Note that the range indicated by the arrow A in FIG. 3 can perform wireless communication with the wireless connection point 32a. When the terminal 26 equipped with the wireless network connection switching device 10 can wirelessly connect to the wireless connection point 32a and perform data communication, the wireless network connection switching device 10 is given an IP address from the DHCP server 24a of the wireless connection point 32a. ing.

  The ping packet transmission / reception unit 12 transmits a ping as a connection confirmation signal to the wireless connection point 32 (default gateway 22) (S1), and receives a ping response output when the default gateway 22 receives the ping ( S2). Thus, the ping packet transmitting / receiving unit 12 repeatedly transmits a ping and receives a ping response to the ping, so that the wireless connection point 32a and the mobile unit (wireless network connection switching device 10) are connected by wireless communication. I always check that.

  Thereafter, as the vehicle 30 moves, the vehicle 30 exits from the communication area 34 of the wireless connection point 32a, and therefore no ping response from the default gateway 22 is received. Then, the ping packet transmission / reception unit 12 instructs the DHCP packet transmission / reception unit 14 to perform the next process (S3). Note that the range indicated by the arrow C in FIG. 3 cannot perform wireless communication with the wireless connection points 32a and 32b.

  Then, the DHCP packet transmission / reception unit 14 searches for the wireless connection point 32 by outputting a DHCP Discover packet. That is, the DHCP packet transmitting / receiving unit 14 repeatedly outputs a DHCP Discover packet that is a search signal (S4). This is performed until a response to the DHCP Discover is received from the wireless connection point 32 (DHCP server 24) that can newly communicate.

  That is, when the vehicle 30 enters the communication area 34 of the wireless connection point 32b, the terminal 26 including the wireless network connection switching device 10 and the wireless communication control unit 28 is connected to the wireless connection point 32b by the processing of the wireless communication control unit 28. A wireless connection is established (S20). Since the DHCP Discover packet is repeatedly output from the DHCP packet transmission / reception unit 14, as described above, as soon as the wireless connection with the wireless connection point 32b is established, the DHCP Discover packet is input to the DHCP server 24b of the wireless connection point 32b. Then, the DHCP server 24b outputs a DHCP Offer, which is a DHCP response, and inputs this to the DHCP packet transmitting / receiving unit 14 (S5).

  The DHCP packet transmitting / receiving unit 14 that has received the DHCP Offer instructs the IP address control unit 16 to make a DHCP request, which is the next process (S6). That is, since the instruction of S6 is input to the IP address releasing means 18, the IP address releasing means 18 performs a process of releasing the old IP address that was used when connecting to the wireless connection point 32a by wireless communication (S7). . At this time, since the connection between the mobile unit side and the wireless connection point 32a has not been established as described above, the IP address releasing means 18 only allows the old IP address to flow on the network. If the connection between the mobile unit and the wireless connection point 32a is established, the old IP address released by the IP address releasing means 18 is received by the DHCP server 24a to which this old IP address is assigned.

Thereafter, the IP address releasing unit 18 instructs the IP address acquiring unit 20 to acquire a new IP address (S8). Then, the IP address acquisition means 20 requests a new IP address from the DHCP server 24b that has output the DHCP Offer (S9). In response to the request in S9, the DHCP server 24b distributes a new IP address to the IP address acquisition means 20 (S10). Then, the IP address acquisition unit 20 acquires and sets a new IP address.
Thereby, the wireless network connection switching device 10 can perform wireless communication with the wireless connection point 32b. In addition, the range shown by the arrow B in FIG. 3 can perform wireless communication with the wireless connection point 32b.

  Since such a wireless network switching method and apparatus 10 constantly monitors the connection of communication between the mobile unit and the wireless connection point 32, when communication cannot be performed, the wireless connection point 32 can be searched immediately. it can. When searching for a new wireless connection point 32, the search signal is repeatedly output. Therefore, as soon as the vehicle 30 enters the communication area 34 and the connection between the terminal 26 and the wireless connection point 32 is established, the IP by DHCP is immediately used. Address acquisition processing can be performed. For this reason, the time from entering the communication area 34 until communication between the mobile unit and the wireless connection point 32 can be shortened. Further, since communication can be performed in the entire communication area 34, the communication area 34 can be used effectively, and more stable wireless communication can be performed.

  Since the wireless network switching method and apparatus can reliably connect to the wireless connection point 32 that passes when the vehicle 30 is moving, acquisition of position information of the vehicle 30 and distribution of information specialized for each wireless connection point 32 is possible. Application to such uses is possible.

  By arranging the wireless network connection switching device based on the communication status monitoring on the bus and installing the wireless connection point at the bus stop, the wireless connection of the information receiving terminal installed in the bus can be stabilized. It can also be used for acquiring bus location information and distributing local information in the vicinity of bus stops.

  Also in rail transport, by installing a wireless connection point at a station and introducing a wireless network connection switching method and device based on communication status monitoring, the same use as in the case of the bus described above can be performed.

  In addition, if a wireless connection point is installed in elementary and junior high schools as a public access point, ambulances, fire-fighting vehicles, police vehicles, administrative vehicles, and vehicles of lifeline-related companies can stably and reliably transmit and receive large files.

It is a block diagram explaining the structure of a wireless network connection switching apparatus. It is a block diagram explaining the wireless network connection of a terminal. It is a figure explaining the relationship between a wireless network connection switching apparatus and a communication area. It is a figure which concerns on a prior art and demonstrates the relationship between a vehicle and a communication area.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ......... Wireless network connection switching apparatus, 12 ......... Ping packet transmission / reception part, 14 ...... DHCP packet transmission / reception part, 16 ...... IP address control part, 18 ...... IP address release means, 20 ...... IP address acquisition means, 22... Default gateway, 24... DHCP server, 30... Vehicle, 32.

Claims (5)

Output a connection confirmation signal from the mobile unit to the wireless connection point, repeat the reception of the response from the wireless connection point to the mobile unit, continue to check the connection between the mobile unit and the wireless connection point,
If the response from the wireless connection point is not received, the search signal of the wireless connection point is repeatedly output from the mobile body.
A wireless network connection switching method based on communication state monitoring. Repeatedly output exploration signals for wireless connection points from moving objects,
When the mobile unit receives a response to the search signal from the wireless connection point, it enables communication with the wireless connection point,
Continue to check the established state of communication between the mobile and the wireless connection point,
A wireless network connection switching method based on communication state monitoring. The connection confirmation signal is ping;
The response for confirming the communication establishment state between the mobile unit and the wireless connection point is a ping response,
The probe signal is a DHCP Discover packet;
The response to the search signal is a DHCP Offer response.
The wireless network connection switching method according to claim 1 or 2, wherein the communication state is monitored.   4. The wireless network connection switching method according to claim 1, wherein the mobile body wirelessly connects to an access point arranged in a network as the wireless connection point. A ping packet transmission / reception unit that continuously transmits a ping to a wireless connection point and receives a ping response from the wireless connection point that responds to the wireless connection point, and continues to check a connection state with the wireless connection point;
When the ping packet transmission / reception unit does not receive the ping response, a DHCP packet transmission / reception unit that searches for the wireless connection point;
An IP address control unit that obtains an IP address from the wireless connection point when there is a reply from the wireless connection point that can be connected by exploration of the DHCP packet transmitting and receiving unit;
A wireless network connection switching device based on communication status monitoring.

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