JP4047884B2 - Wireless LAN system, access point connection switching method thereof, and control program therefor - Google Patents

Description

  In the roaming operation of a mobile terminal equipped with a wireless LAN function and a plurality of wireless LAN access points, the present invention does not depend on the roaming function possessed by each wireless LAN device, and the actual communication state between the mobile terminal and the host device The wireless LAN access point connection switching method for switching the connection destination of the wireless LAN access point at an appropriate timing.

  Conventionally, wireless LAN devices have a roaming function, and even if the terminal moves to an area where the radio wave of the connected wireless LAN access point is weak and affects wireless LAN communication, the same communication settings are set in that area. If there is a wireless LAN access point where radio waves are stronger and communication stability can be expected, the connection destination can be automatically switched to expand the user's communication usage range and maintain communication stability. .

  In general, many wireless LAN devices have the same SSID (Service Set Identifier) and settings for communication even if they move between physically different access points. There is a roaming function that automatically switches access points.

In addition, there is a wireless LAN communication device in which an access point transmits a ping packet to a terminal device while changing the output intensity and grasps the connection status with the terminal device by checking the presence / absence of a response (for example, Patent Literature) 1).
JP 2004-72594 A

  However, there are various types of wireless LAN devices at the present time when wireless LAN networks are widespread, and it is common that different LAN controllers are used on the mobile terminal side and the access point side. In this case, each wireless LAN device is used. The following problems exist because the functions of are not fully demonstrated.

  The first problem is that since different LAN controllers are mainly used on the mobile terminal side and the access point side, the connection switching timing of the access point called roaming is delayed, and as a result, even within the radio wave reachable range of the access point. An area where communication is not possible may occur.

  The second problem is that an access point may be prepared in advance as a communication infrastructure, and it is difficult for a general user to select a mobile terminal equipped with the same LAN controller as the communication infrastructure.

  In this case, if the connection destination is switched to another wireless LAN access point, the roaming operation is not performed as described above even though it is a communicable area and does not affect the original communication. Therefore, connection to another wireless LAN access point is not switched, and as a result, data communication may be hindered.

  Therefore, the present invention does not depend on the communication infrastructure and the type of LAN controller installed in the wireless LAN device, and switches the connection of the access points when the actual communication state is monitored and a communication unstable state is detected. An object of the present invention is to provide a wireless LAN system that secures a stable communication environment, an access point connection switching method thereof, and a control program thereof.

  In order to solve the above-mentioned problems, the present invention sends ICMP (Internet Control Message Protocol) ping data to a host device at regular intervals from a mobile terminal, and whether the response is within an appropriate communication area. Whether or not it is within an appropriate communication area, the access point is scanned, and reconnection to a wireless LAN access point capable of ensuring communication stability in that area is performed.

  With the above configuration, the actual communication state is monitored based on the presence / absence of a ping response from the mobile terminal to the host device. If the ping does not respond, the connection point of the access point can be switched to ensure a stable communication environment.

  According to the present invention, by verifying whether or not communication with a higher-level device is possible based on the presence / absence of a response to ping data transmitted from a mobile terminal, it is possible to establish a wireless connection destination in a state closer to actual communication without depending on the conventional roaming function A LAN access point switching operation can be performed. As a result, stable communication can always be provided.

  Next, the best mode of the present invention will be described with reference to the drawings.

  The mobile terminal is equipped with a utility tool capable of confirming various settings and communication states in wireless LAN communication. This utility tool has a function that can scan the wireless LAN access point, emits the strongest radio wave among the wireless LAN access points detected by the scan, and has the same communication settings. The wireless LAN access point is reconnected.

  The mobile terminal sends ping data to the host device via the wireless LAN access point and the HUB. At this time, if the wireless LAN access point has strong radio waves and there are no obstacles that block the radio waves and the communication state is good, a response is returned from the host device, but the radio LAN access point radio waves are weak or obstructions that block the radio waves, etc. If the communication state is unstable due to the presence of the device, there is no response from the host device.

  When expanding a communication area across a plurality of wireless LAN access points using a roaming function, it is common to arrange each wireless LAN access point so that radio wave arrival ranges of different wireless LAN access points overlap.

  Therefore, when the currently connected wireless LAN access point is the center, the radio wave of the wireless LAN access point that can be received by the mobile terminal is weakened as the mobile terminal moves away from the wireless LAN access point. The radio wave of the other wireless LAN access point that starts to cover the area becomes stronger.

  For these reasons, if there is no response to the ping data sent to the host device, it is determined that communication with the currently connected wireless LAN access point is unstable, and the utility tool automatically A wireless LAN access point scan function is executed. As a result, the strongest radio wave among the detected wireless LAN access points can be emitted and the wireless LAN access point having the same communication settings can be reconnected, and a stable communication environment can be continuously provided. be able to.

  FIG. 1 shows a system configuration of an embodiment of the present invention. In this figure, a mobile terminal (mobile PC, PDA, etc.) 10 is in an environment where it can communicate with an upper device (server, PC, etc.) 40 via an access point AP-1 (21) and a HUB 30. The mobile terminal 10 is preinstalled with a wireless LAN utility tool 101 and a ping response confirmation tool 102 for wireless LAN communication. The wireless LAN access points AP-1 (21) to AP-n (23) have the same communication settings in advance, and the mobile terminal 10 is connected to any of the wireless LAN access points via the wireless LAN. . In addition, the mobile terminal and the host device realize each function described below by a control program stored in each memory.

  FIG. 2 is an image of the radio wave intensities of AP-1 (21) and AP-2 (22) shown in FIG. 1. Here, the influence of obstacles existing in the actual communication environment is taken into account. Not. In this figure, the radio wave of AP-1 (21) becomes weak by moving away from the center of AP-1 (21), and on the contrary, the radio wave of AP-2 (22) becomes stronger because it goes toward the center. Is shown.

  The configuration of the embodiment of the present invention has been described above. The configuration of the LAN network using the HUB 30 in FIG. 1 and the communication setting contents and settings of the mobile terminal 10, AP-1 (21) to AP-n (23) are described. Since the method is well known to those skilled in the art and is not directly related to the present invention, its detailed configuration is omitted.

  In the present invention, whether or not communication between the mobile terminal 10 and the host device 40 is important, and the network configuration and the type of device for realizing the communication are not inherently directly related. Therefore, implementation with a network configuration and equipment different from those in FIG. 1 does not affect the present invention.

  Next, the operation of the present invention will be described with reference to FIGS. As shown in FIG. 1, the mobile terminal 10 exists in a communicable area of the wireless LAN access point 21 and is in a place with good communication.

  First, step S1 of the sequence shown in FIG. 3 shows the state of FIG. 4, and the mobile terminal 10 pings the host device 40 at regular intervals via the AP-1 (21) and the HUB 30. Data 103 is transmitted. In addition, although the interval time of ping transmission is generally variable, in this embodiment, the time is 1 second. At this time, if there is a response 104 from the host device, it means that the mobile terminal 10 is located in an area where the radio wave intensity is sufficient and the communication is good, and the mobile terminal 10 continuously sends the ping data 103 at regular intervals. I do.

  However, as shown in FIG. 5, when the mobile terminal 10 moves away from AP-1 (21) and moves in a direction approaching AP-2 (22), the radio wave of AP-1 (21) becomes weak and communication is unstable. It becomes. At this time, since the response from the host device 40 is not returned to the ping data 103 sent from the mobile terminal 10 as step S2 in FIG. 3, the mobile terminal 10 detects the timeout 105 one second after sending the ping data. To do.

  When the state of step S2 occurs, the mobile terminal 10 determines that communication with the currently connected AP-1 (21) has become unstable, and the wireless LAN access point connection destination in step S3 of FIG. Switch. At this time, the mobile terminal 10 uses the wireless LAN access point / scan function 106 installed in the wireless LAN device, to the wireless LAN access point with the strongest radio wave and the same communication settings at that time. Switch connection. Here, since it moved from AP-1 (21) toward AP-2 (22), the connection is switched to AP-2 (22) by the operation of the scan function, and data transmission / reception is continued in a stable communication state. It can be performed.

  As described above, in this embodiment, the mobile terminal 10 equipped with a wireless LAN device pings the host device 40 such as a server or PC via the wireless LAN access points 21 to 23 and the HUB 30 at regular intervals. Ping data 103 is sent from the response confirmation tool 102.

  At this time, when the ping response 104 is confirmed from the host device, it is determined that the area is a communicable area with the currently connected wireless LAN access point 21, and switching of the connection destination of the wireless LAN access point 21 is not necessary. .

  However, if there is no ping response 104 from the host device and a communication timeout occurs, it is determined that the area is incapable of communicating with the currently connected wireless LAN access point 21, and the wireless LAN utility 101 on the terminal side functions. The connection switching operation to the other wireless LAN access points 22 and 23 covering the area is performed by using the access point scanning function.

  In this way, in the present invention, the actual communication state performed between the mobile terminal 10 and the host device 40 is monitored by the presence or absence of the response 104 of the ping data 103, so that the mobile terminal 10 can communicate and the communication is stable. It is possible to determine whether the area is to be performed in a state closer to the actual state. Therefore, it is possible to switch the connection destination wireless LAN access point at a more appropriate timing than the roaming operation performed by the LAN controller and the wireless LAN driver installed in the wireless LAN device.

  In order to realize the operation of the above embodiment, a software program for performing a series of operations on an existing mobile terminal is required. However, since the ping and wireless LAN access point scan functions used in the present invention are general basic functions in a wireless LAN, it is possible to incorporate these series of operation methods in the wireless LAN driver in advance.

  In addition, although ping is used in the present invention to determine whether or not communication with a host device is possible, data communication of other software programs installed in the mobile terminal and its timeout are not used to verify whether or not communication is possible. It is also possible to implement using functions.

It is a system configuration figure of one example of the present invention. It is explanatory drawing of the radio wave intensity of AP-1 and AP-2. It is a sequence diagram of an example. It is a figure which shows the state of step S1. It is a figure which shows the state of step S2.

Explanation of symbols

10 Mobile terminals 21, 22, 23 Access point 30 HUB
40 Host device

Claims (3)

In a wireless LAN system including a mobile terminal and a host device connected to a plurality of access points,
The mobile terminal
A communication confirmation request sending function;
With access point scanning function,
The host device is
A communication confirmation response function for the communication confirmation request;
The mobile terminal
Using the ping data ICMP (Internet Control Message Protocol) to the communication confirmation by the communication confirmation request sending function, if there is no communication acknowledgment within after sending the ping data as a communication confirmation request predetermined time, the access point A wireless LAN system that scans and switches the connection to the access point that emits the strongest radio waves. An access point connection switching method of a wireless LAN system including a mobile terminal and a host device connected to a plurality of access points,
The mobile terminal uses ICMP ping data for communication confirmation , sends the ping data to the host device as a communication confirmation request , and scans an access point if there is no communication confirmation response within a predetermined time from the transmission. And switching the connection to the access point that emits the strongest radio wave. An access point connection switching control program for a mobile terminal of a wireless LAN system,
ICMP ping data is used for communication confirmation, the ping data is sent as a communication confirmation request to a host device connected to a plurality of access points, and if there is no communication confirmation response within a predetermined time from the transmission, the access point is A wireless LAN access point connection switching control program which causes the mobile terminal to execute a function of scanning and switching a connection to an access point emitting the strongest radio wave.

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