Patent Application
20050105501
This application claims the benefit of Japanese Patent Application No.: 2003-389435, filed on Nov. 19, 2003, which is incorporated herein by reference.
The present application relates to a method and apparatus for accessing an access point (AP) of a wireless local area network (LAN) and a station, and more particularly to a method for accessing an AP of a wireless LAN that can access APs in more than one country worldwide from a station.
APs for wireless LAN have been widely deployed in stores and in various public areas, and users can use various telecommunication services through these APs. In addition, since international telecommunication services are growing rapidly, it may be desirable that the stations support a worldwide roaming function for accessing the wireless LANs.
Devices that have the capability to access APs in a wireless LAN, for example, PCs and portable computing appliances such as PDAs, need to be equipped with a station access application program for accessing the AP of the wireless LAN. Conventionally, when a user accesses APs of worldwide wireless LANs using such a device, the device needs to install a country-specific station application program (e.g., Japanese, Chinese, USA, UK) according to the type of the operating system (OS) installed in the PCs. During the process of accessing APs, the device changes operating parameters such as carrier frequency and channel, according to the information in a beacon that is received from the AP in the wireless LAN. Therefore, this method has a disadvantage in that a longer time is required to connect to the AP.
Prior to changing the operating parameters such as carrier frequency and channel, a beacon is received from the AP by scanning all of the possible channels (for example, all channels in the 2.4 GHz and 5.0 GHz bands for WiFi) including the parameters, when a user accesses an AP, and data, including the country information, is received from the beacon. Subsequently, the scanning must be performed at the channels corresponding to the country. Conventional methods have a problem in that they take a significant amount of time to connect to a desired AP.
These problems may become more severe since wireless LANs are internationally used and the number of the channels used increases, especially at 5.0 GHz, as well as the authorized frequency bands and protocols (as examples, IEEE 802.11a,b,g and h).
A conventional method for accessing AP in wireless LAN is disclosed in Japanese Unexamined Patent Application Publication No. 2000-184439.
A method more efficiently and rapidly accessing the AP of a wireless LAN and the country information concerning a region where a user accesses the AP, and a station having a worldwide roaming capability, is described.
One aspect provides a method for accessing an access point (AP) in a wireless LAN, comprising extracting country information from a beacon received from the access point when accessing the access point, and communicating with the access point by connecting to the access point which is included in a profile corresponding to the extracted country information; storing, in a memory, the country information extracted by connecting to the access point and profile information including information about the access point which may be used in the communicating step, and accessing the access point based on the country information and the stored profile information, including the access point, which may stored in the memory, when next accessing an access point.
Another aspect provides a station, which has worldwide roaming function, for accessing an access point in wireless LAN, the station comprises means for extracting country information included in a beacon received from the access point when the station accesses the access point, means for communication with the access point by connecting to the access point which is included in a profile of the extracted country information, and means for storing, in a memory, the country information extracted by connecting to the access point or profile information including information about the access point which may be used in the communicating step. When next accessing an access point, the access to the access point is performed based on the country information and the profile information including the information about the access point, which may be stored in the memory.
Exemplary embodiments may be better understood with reference to the drawings, but these embodiments are not intended to be of a limiting nature. Like numbered elements in the same or different drawings perform equivalent functions.
The environment for accessing the AP is shown in
The PC 12 comprises a STA 13 with a worldwide (multi-country) roaming function and an OS 14. The STA 13 in which application programs are installed has functions that may discriminate the OS type and AP type of the wireless LAN. The PC may be a laptop computer, hand-held appliance (such as a PDA, cell phone) or the like, having at least non-volatile memory, a computational circuit, and adapted to interface with a STA. The STA may be integral to the PC or separate, such as a plug-in unit. The OS may be a stored program with characteristics appropriate for the countries where the device is intended to be operated, and may include all of the world for specific communications protocols. The OS may be stored in a memory of the PC. The term personal computer (PC) may be used to refer to the operative combination of the PC, the STA and the OS, whether incorporated in a single housing or separately, but acting together. (The term worldwide, is be used to signify that the device is constructed and/or programmed to operate in at least two countries.)
In order to roam worldwide, the STA 13 may first scan all channels (for example, in 2.4 GHz and 5.0 GHz bands), for the pre-programmed country specifications, to receive a beacon signal from the AP 11. It receives frames including the country information from the beacon and then changes the profile information based on the country information which may be contained in the beacon signal and the frames. The STA 13 may manage the profile group for each country. The beacon signal may include a Service Set Identifier (SSID), and the SSID may contain country information. The country profile table groups may be located in the PC and managed by the OS.
An example of profile groups that may be used, is shown in
When the access to the AP 11 is first performed, the STA 13 in the PC 12 receives a beacon from the AP 11 which can be received at the location of the PC 12, extracts the country information from information included in the beacon, and selects the country group profile tables shown in
Referring to flowchart shown in
(1) A pre-determined country is selected initially, and a corresponding profile is initially set up (Step 301 and 302).
(2) The STA 13 scans one or more accessible connecting APs and searches for a valid network list, using the initially set profile information, and then acquires the country information included in the beacon that is received from the AP (Step 303 and 304).
(3) The STA 13 compares the country information in Step 301 with the country information acquired in Step 304, and determines whether or not they are same. If they are not the same, the profiles are updated to the country that is acquired from the information in the beacon. The country and profile update is performed by selecting a profile of the country group table corresponding to the country information, as shown in
(4) If the access to the AP according to the profile in Step 306 fails, the STA 13 tries to sequentially access an AP from the multiple profiles in the corresponding country group profile table (Step 307). The process is described in detail referring to the flowchart shown in
(5) By accessing the AP in Step 307, determination of whether or not the AP for the location of the connection (also referred to as the connecting place) is found. If the STA 13 finds a valid AP, the STA connects to the AP. However, if the STA 13 fails to find a valid AP, it tries to find another valid AP (an AP having same or different country information) by repeating the procedure from Step 303 (Step 308 and 309).
Next, the detailed procedure for Steps 307 and 308 for accessing the AP will be described with reference to the
(1) If the process starts, the STA tries to access the APa that is set as the first profile (Set A) in the profile table of the country corresponding to a country profile group table for the country which is initially set in the utility (Step 401). (APn represents any of the AP in the Set N of the selected country group.)
(2) As a result of the access to APa in Step 401, the STA in the user PC determines whether the access to APa is possible using a response from APa. If access is not possible, the STA tries to access APb that is set as the next profile (Set B) in the table of the corresponding country (Step 402 and 403).
(3) In the same way, as a result of the access to APb in Step 403, the STA determines whether the access to APb is possible or not using a response from APb. If access is not possible, the STA tries to access APc that is set as the next profile (Set C) in the table of the corresponding country. If access fails, the STA tries to access the AP after the next one so that the STA sequentially tries to access APs which are set to all profiles stored in the table of the corresponding country until the final profile (Set N) is reached. If access still fails, the STA moves to the procedure in Step 303 because a valid AP cannot be found (Step 404, 405 to 40n). Other country group settings and profiles can be searched, however the current country setting may not be changed until a new country setting has been determined, by a beacon or connection to an AP. This may minimize reconnection time where the station has not changed country location, but is temporarily unable to access an AP; this may occur, for example, by moving out of range of all APs or by a temporary service failure by the wireless LAN.
(4) In Step 402, 404, and 40n, the STA moves to the procedure in Step 309 if it can access an AP that is set up in the selected profile.
By connecting in Step 309, the PC 12 including STA 13 communicates with the AP 11, and receives various services. STA 13 stores the information of the profile, which is used in communicating with the AP 11, or the country information, into a non-volatile memory, hard disc, or the like, which is provided in the STA 13 or the PC 12.
When accessing to another AP, it is possible to more rapidly and easily access the AP by using the stored profile information or the country group information. When user moves the PC location in the same country, it is possible to more conveniently and quickly access the AP. When moving between countries, the method identifies the new country and updates the country information so that the next AP is accessed more conveniently and quickly.
The method can be performed using an application program or OS whose instructions may be stored in various media such as HD, DAT, FD, DVD-ROM, CD-ROM, and executed with a suitable computer or microprocessor.
As a result of the method for accessing AP in wireless LAN, by receiving the beacon from the AP 11 that can be received in the present location and extracting the country information from the information in the beacon, the method selects the country profile group table for the country based on the extracted country information to try to systematically access the AP 11 based on the profile information which is stored and managed in the table. Therefore, users can more conveniently and more quickly perform repeated access to the AP 11. Systematically connotes that there is one or more preprogrammed logical sequences in which the attempt to access the AP 11 is made. The selection of the preprogrammed logical sequence may be made based on a previous state of the device, operator input, or the like.
It will be evident to one skilled in the art that the method need not be performed in the order described in the embodiments, and the method may be commenced at various points in the sequence described, depending on the previous status of the communications station and the details of the OS or control program, or based on operator input.
Users can easily determine the AP information concerning the country where the user accesses APs during worldwide roaming as well as can more conveniently and more quickly perform connection to access points.
Further, the use of the word country does not limit the use of the method or apparatus to situation where country is synonymous with a political entity. Rather, any geographical area where a network is deployed, and where it may be useful to differentiate between networks, is intended. In addition, geographical areas associated with networks may overlap.
Although only a few exemplary embodiments of this invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of the invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2003-389435 | Nov 2003 | JP | national |
