JP4463085B2 - Wireless LAN system and method for roaming to a specific wireless LAN access point - Google Patents

Description

  The present invention relates to a wireless LAN technology, and more particularly to a roaming technology in an infrastructure type wireless LAN.

  Conventionally, in a wireless LAN access point and a wireless LAN terminal, roaming is realized by a roaming method defined in IEEE 802.11. According to this, devices compliant with IEEE 802.11 can be connected wirelessly. However, when a wireless LAN terminal is connected to a wireless LAN access point having a specific function, the wireless LAN terminal is connected to the connected wireless device. There was a problem that a LAN access point could not be selected.

  For example, in a conventional wireless LAN terminal roaming method, when a wireless LAN terminal searches for a roaming destination wireless LAN access point, the MAC address of the wireless LAN access point and the name of the wireless LAN network called SSID (or the wireless LAN access point) The only way to distinguish a wireless LAN access point with a specific function is to have a specific MAC address or a specific SSID to distinguish it from others. There wasn't.

In addition, when the terminal receives access point information having an identification code different from the access point of the currently participating network, the wireless LAN stores the information in a nonvolatile memory and performs network switching based on the information. There is a network switching method (for example, see Patent Document 1).
JP 2004-229225 A

  However, in the method of giving a specific MAC address, the wireless LAN terminal needs to know the specific MAC address in advance, and the MAC of the wireless LAN access point having a specific function when the wireless LAN access point is produced. There is a problem that management is troublesome, such as distinguishing addresses from others.

  In addition, in the method of giving a specific SSID, setting for hiding the SSID is generally performed for security. In this case, when the wireless LAN terminal searches for a wireless LAN access point for roaming, the SSID is set. There is a problem that it cannot be distinguished by SSID because it cannot be seen.

  In addition, in an example in which a specific function is realized by a combination of a wireless LAN terminal and a wireless LAN access point of the same manufacturer, specific information is put in a synchronization signal called a beacon transmitted from the wireless LAN access point, When a wireless LAN terminal receives this, a specific wireless LAN access point can be found. However, in order to put specific information in a beacon, it is necessary to create a wireless LAN device driver or the like. There was a problem that it was very difficult unless it was a device manufacturer.

  Therefore, the present invention provides a specific wireless that enables a wireless LAN terminal to roam to a wireless LAN access point having a specific function when the wireless LAN terminal performs roaming in an environment where wireless LAN access points having different functions are mixed in the same network. An object is to provide a roaming method to a LAN access point.

In order to solve the above problems, the present invention is a wireless LAN system in which a plurality of wireless LAN access points are connected to a network and wireless LAN communication is performed by roaming a wireless LAN terminal to the wireless LAN access point. The plurality of wireless LAN access points are connected to a wireless LAN access point having a specific function and a wireless LAN access point not having the specific function, and has the specific function. The wireless LAN access point has means for transmitting a specific frame including data indicating that the specific function is provided when connected to the wireless LAN terminal, and the wireless LAN terminal is connected to the wireless LAN access point. The specific frame from the wireless LAN access point The first table that stores the MAC address of the wireless LAN access point when the wireless LAN access point is received, and the wireless LAN when the specific frame is not received from the wireless LAN access point when connected to the wireless LAN access point A second table that stores the MAC address of the access point and the first and second tables when roaming to the wireless LAN access point is started, and the MAC address of the wireless LAN access point is stored in the first table. Means for performing roaming to the wireless LAN access point only in a certain case .

  According to the present invention, when a wireless LAN terminal roams, it is determined whether or not the wireless LAN access point has a function based on a specific data frame each time roaming, and a wireless LAN access point that does not have a function based on a specific data frame By not roaming, there is an effect that it is possible to reliably roam to a wireless LAN access point having a specific function.

  For this reason, it is not necessary for the wireless LAN terminal to register the MAC address of the wireless LAN access point having a specific function at the time of production or manually, and the wireless LAN terminal is automatically identified without discrimination by SSID. It is possible to roam to a wireless LAN access point having the above function.

  Further, by sharing the information obtained by the wireless LAN terminals between the wireless LAN terminals as to whether or not the wireless LAN access point has a function based on the specific data frame, more wireless LAN terminals can surely have a specific function. It is possible to roam to a wireless LAN access point having

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

  FIG. 1 shows a configuration example of the present invention, which includes a wireless LAN access point and a wireless LAN terminal.

  The wireless LAN access point includes a specific data frame configuration unit 11 and a radio unit 12 that configure a specific data frame.

  The wireless LAN terminal includes a header detection unit 24 that detects a specific data frame from a signal received by the wireless unit 21, a MAC address table a25 that stores a MAC address of a wireless LAN access point having a specific function, and a specific function. MAC address table b26 for storing the MAC address of the wireless LAN access point that does not have, the search results obtained from the search unit 22 of the wireless unit and these tables are referred to determine the MAC address of the roaming destination, It is comprised from the inquiry judgment part 27 notified to the roaming part 23. FIG.

  FIG. 2 shows an example of the present invention, in which a plurality of wireless LAN access points are connected on the same network. In order to simplify the description, two wireless LAN access points are connected in FIG. 2, but more may be used. Further, the wireless LAN access point 1 (hereinafter referred to as AP1) and the wireless LAN access point 2 (hereinafter referred to as AP2) are partially overlapped in wireless area. A wireless LAN terminal 1 (hereinafter referred to as STA1) is attempting to wirelessly connect to AP1.

  AP1 and STA1 in FIG. 2 have specific functions and are provided with the means of the present invention shown in FIG. The specific functions described here include, for example, a QoS (Quality of Service) function for giving priority to specific data, and only when the wireless LAN terminal and the wireless LAN access point have similar functions. Since it is effective, when connected to a wireless LAN access point that does not have this function, there is a problem that specific data is not prioritized.

  In FIG. 2, first, STA1 establishes a wireless connection with AP1. At the stage of wireless connection, AP1 transmits to STA1 the specific data frame created by the specific data frame section shown in FIG.

  FIG. 3 shows an example of the configuration of a specific frame. Data indicating that the data frame portion has a specific function is placed. Here, as an example, the value “fff5” is entered. Here, the STA1 receives the specific data frame, and the header detection unit shown in FIG. 1 detects the specific data frame to determine that the wireless LAN access point has a specific function, and sets the MAC address of the AP1. Store in the MAC address table a.

  Next, a series of operations during roaming will be described with reference to the flowchart shown in FIG.

  First, STA1 moves toward AP2 while searching for a wireless LAN access point (S1). Since AP1 and AP2 partially overlap the wireless area, STA1 enters the wireless area of AP2 and determines whether to roam from AP1 to AP2 when the electric field strength of AP2 is stronger than AP1 ( S2). The roaming / query determination unit of STA1 in FIG. 1 queries the MAC address of AP2 detected in the active scan or the passive scan with the MAC address table a and the MAC address table b in FIG. If there is an address (Yes in S3), the roaming unit is instructed to start roaming to AP2 (S5), and if the MAC address of AP2 is in the MAC address table b (Yes in S4) The roaming unit is not instructed to roam.

  If the MAC address of AP2 does not exist in either the MAC address table a or the MAC address table b (No in S4), the roaming / inquiry judging unit instructs the roaming unit to start roaming. After wireless connection, STA1 waits for transmission of a specific data frame from AP2. Here, for example, a one-second timer is provided in the specific frame receiving unit of STA1, and control is performed such as determining whether or not AP2 has a specific function depending on whether or not a specific frame can be received within this time.

  Here, when AP2 does not have a specific function, since a specific frame is not transmitted, STA1 cannot receive the specific frame. Therefore, AP2 determines that AP2 does not have a specific function, and sets AP2's MAC address. Store in the MAC address table b. In this case, since the AP 2 does not have a specific function, depending on the type of the function, there may be a problem if it is connected as it is, so that control for starting roaming may be performed again.

  Specifically, in the STA1, the roaming / query determination unit once again retrieves the search result of the wireless access point from the search unit, and inquires with the MAC address table a and the MAC address table b. Here, STA1 is located where the wireless areas of AP1 and AP2 overlap, the MAC address of AP1 and AP2 is in the search unit, the MAC address of AP1 is in MAC address table a, and AP2 is in MAC address table b. Therefore, the roaming / query determination unit starts roaming to AP1 by issuing a roaming instruction to AP1 to the roaming unit.

  Next, another embodiment of the present invention will be described in detail with reference to the drawings.

  Referring to FIG. 5, compared with FIG. 1, as a function of the wireless LAN access point, the wireless LAN terminal MAC address siphoning unit 13 extracts the MAC address information of the wireless LAN terminal connected to its own wireless area from the wireless unit 12. Has been added. Further, in the previous embodiment, the wireless LAN terminal has only detected the specific data frame by the header detection unit, but here, the function of further reflecting the contents of the specific data frame to the MAC address table a and the MAC address table b. Have

  Next, referring to FIG. 6, a wireless LAN access point 3 (hereinafter referred to as AP3) having a specific function and a wireless LAN terminal 2 (hereinafter referred to as STA2) exist and are connected wirelessly. In addition, the AP 3 is wirelessly connected to a wireless LAN terminal 3 (hereinafter referred to as STA 3). Here, it is assumed that AP3 and STA2 and STA3 have specific functions, and STA2 and STA3 have a common multicast address for reception. Here, the STA2 stores several MAC addresses in the MAC address table a and the MAC address table b by the method shown in this embodiment, and the STA3 has nothing in the MAC address table a and the MAC address table b. Is also not stored.

First, AP3 transmits the IP addresses of STA2 and STA3 in the multicast specific data frame shown in FIG. Here, multicast is used because the specific data frame transmitted from AP3 is common to all wireless LAN terminals, but the same effect can be obtained even if transmission is performed by unicast to individual wireless LAN terminals. . Here, in order to indicate a particular data frame for notifying the MAC address connected, "ff00" provided a header that, IP for all wireless LAN terminals are then connected wirelessly to AP3 The address is entered.

The STA2 having the MAC address in the MAC address table a and the MAC address table b receives this and can know the IP address of the STA3. At this time, STA2 transmits MAC address table a and MAC address table b to STA3 in the specific data frame shown in FIG. Here, in order to indicate that the frame is a specific frame for notifying the MAC address table a and the MAC address table b, a header “ff77” is provided, and then the header “ff88” is added to the MAC address table a. The data further includes the header of “ff99” and the data of the MAC address table b. This specific data frame reaches STA3 via AP3 .

  By reflecting the contents of this specific data frame in its own MAC address table a and MAC address table b, the STA 3 can have the MAC address table a and the MAC address table b without roaming. Born. At this time, even if the STA3 already has the MAC address table a and the MAC address table b, the STA2 and the STA3 notify their own MAC address table a and the MAC address table b in the same manner, and their own MAC address When the other party has more information than the table a and the MAC address table b, there is an advantage that more information can be acquired by adding to the own table.

  As another example, in the configuration of FIG. 6, the STA2 has a function of transmitting a multicast, so that if the STA2 transmits the specific data frame of FIG. 8 by multicast, the STA3 directly transmits the specific data frame. Since it can be received, there is an advantage that STA2 does not need to be notified of the IP address of STA3 from AP2.

It is a block diagram of the wireless LAN access point and wireless LAN terminal of this invention. It is explanatory drawing which shows arrangement | positioning of the wireless LAN access point and wireless LAN terminal of this invention. It is a figure which shows the structural example of a specific frame. It is a flowchart explaining a series of operation | movement at the time of roaming. It is a block diagram of the wireless LAN access point and wireless LAN terminal of Example 2 of this invention. It is explanatory drawing which shows arrangement | positioning of the wireless LAN access point and wireless LAN terminal of Example 2 of this invention. It is a figure which shows the structural example of the specific data frame of a multicast. It is a figure which shows the structural example of the specific data frame notified to another terminal.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Specific data frame structure part 12 Wireless part 13 Wireless LAN terminal MAC address siphoning part 21 Wireless part 22 Search part 23 Roaming part 24 Header detection part 25 MAC address table a
26 MAC address table b
27 Roaming / Inquiry Judgment Department

Claims (6)

A wireless LAN system in which a plurality of wireless LAN access points are connected on a network and wireless LAN communication is performed by roaming a wireless LAN terminal to the wireless LAN access point,
The plurality of wireless LAN access points are connected to a wireless LAN access point having a specific function and a wireless LAN access point not having the specific function,
The wireless LAN access point having the specific function has means for transmitting a specific frame including data indicating that the specific function is provided when connected to the wireless LAN terminal,
The wireless LAN terminal is
A first table that stores the MAC address of the wireless LAN access point when the specific frame is received from the wireless LAN access point when connected to the wireless LAN access point;
A second table that stores the MAC address of the wireless LAN access point when the specific frame is not received from the wireless LAN access point when connected to the wireless LAN access point;
Means for referring to the first and second tables when starting roaming to the wireless LAN access point and performing roaming to the wireless LAN access point only when the MAC address of the wireless LAN access point is in the first table And a wireless LAN system. The wireless LAN access point having the specific function is:
Means for collecting IP addresses of wireless LAN terminals connected to its own wireless area;
Means for inserting the collected IP address into a specific data frame and transmitting to a wireless LAN terminal connected to the own wireless area;
The wireless LAN terminal is
Means for receiving the specific data frame, obtaining an IP address of another wireless LAN terminal in the wireless area, and transmitting the MAC addresses of the first and second tables of the device to the IP address;
Means for receiving the MAC addresses of the first and second tables transmitted from other wireless LAN terminals in the wireless area;
The wireless LAN terminals in the wireless area transmit and receive the MAC addresses in the first and second tables, and the MAC addresses transmitted from other wireless LAN terminals in the first and second tables respectively. The wireless LAN system according to claim 1, wherein the wireless LAN system is reflected . The wireless LAN terminal includes means for multicast transmission of the MAC addresses of the first and second tables to another wireless LAN terminal in the wireless area to which the wireless LAN terminal is connected, and another wireless in the wireless area. Means for receiving the MAC addresses of the first and second tables transmitted from the LAN terminal,
The wireless LAN terminals in the wireless area transmit and receive the MAC addresses in the first and second tables, and the MAC addresses transmitted from other wireless LAN terminals in the first and second tables respectively. The wireless LAN system according to claim 1 , wherein the wireless LAN system is reflected . A wireless LAN system roaming method in which a plurality of wireless LAN access points are connected to a network and wireless LAN communication is performed by roaming a wireless LAN terminal to the wireless LAN access point,
The plurality of wireless LAN access points are connected to a wireless LAN access point having a specific function and a wireless LAN access point not having the specific function,
The wireless LAN access point having the specific function has means for transmitting a specific frame including data indicating that the specific function is provided when connected to the wireless LAN terminal,
The wireless LAN terminal is
Storing the MAC address of the wireless LAN access point in the first table when the specific frame is received from the wireless LAN access point when connected to the wireless LAN access point;
Storing the MAC address of the wireless LAN access point in the second table when the specific frame is not received from the wireless LAN access point when connected to the wireless LAN access point;
The process of referring to the first and second tables when starting roaming to the wireless LAN access point and performing roaming to the wireless LAN access point only when the MAC address of the wireless LAN access point is in the first table And a roaming method to a specific wireless LAN access point. The wireless LAN access point having the specific function is:
Means for collecting IP addresses of wireless LAN terminals connected to its own wireless area;
Means for inserting the collected IP address into a specific data frame and transmitting to a wireless LAN terminal connected to the own wireless area;
The wireless LAN terminal is
Means for receiving the specific data frame, obtaining an IP address of another wireless LAN terminal in the wireless area, and transmitting the MAC addresses of the first and second tables of the device to the IP address;
Means for receiving the MAC addresses of the first and second tables transmitted from other wireless LAN terminals in the wireless area;
The wireless LAN terminals in the wireless area transmit and receive the MAC addresses in the first and second tables, and the MAC addresses transmitted from other wireless LAN terminals in the first and second tables respectively. The method of roaming to a specific wireless LAN access point according to claim 4, wherein: The wireless LAN terminal includes means for multicast transmission of the MAC addresses of the first and second tables to another wireless LAN terminal in the wireless area to which the wireless LAN terminal is connected, and another wireless in the wireless area. Means for receiving the MAC addresses of the first and second tables transmitted from the LAN terminal,
The wireless LAN terminals in the wireless area transmit and receive the MAC addresses in the first and second tables, and the MAC addresses transmitted from other wireless LAN terminals in the first and second tables respectively. The method of roaming to a specific wireless LAN access point according to claim 4 , wherein:

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