Abstract:
The terminal according to the present application has a connection unit that connects to an access point for a communication network The terminal also has a connection control unit that scans a network registered in a connection list, subtracts access points registered in a exclusion list from the detected access points to identify access points to which connection is possible, initializes the exclusion list if an access point to which connection is possible is not identified and then again identifies an access point to which connection is possible, and selects an access point to connect to, out of identified access points to which connection in possible. The terminal further has a connection ending unit that, if the start of a connection to an access point registered in a duplicate exclusion list is detected, cuts the connection with the access point, and also deletes the corresponding network from the connection list.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is a National Phase Patent Application and claims priority to and the benefit of International Application Number PCT/JP2013/060742, filed on Apr. 9, 2013, which claims priority to Japanese Patent Application Number 2012-150449, filed on Jul. 4, 2012, Japanese Patent Application Number 2012-151436, filed on Jul. 5, 2012, and Japanese Patent Application Number 2012-217195, filed on Sep. 28, 2012, the entire disclosures of which are incorporated herein by reference. 
     TECHNICAL FIELD 
     Embodiments discussed in the present specification relate to a terminal which is capable of connecting to a communication network, and a method for connecting the terminal. 
     BACKGROUND 
     In recent years, portable terminals which are capable of connecting to a plurality of heterogeneous communication networks, such as a mobile phone network and a wireless local area network (LAN), as a standard function have come to be widely utilized. With such a portable terminal, communication can be continuously performed among the plurality of communication networks, by properly switching the communication network (communication channel) to be connected or utilized (hereinafter referred to as “handover”). 
     Regarding the technique related to the handover among the plurality of communication networks, Patent Literature 1 discloses a technique that enables the handover to be stably performed between the mobile phone network and the wireless LAN, without interrupting data communication. According to the cited document, the communication network is switched to the wireless LAN when the reception level of the wireless LAN continuously exceeds a threshold for a predetermined period of time while the terminal is connected to the mobile phone network, and the communication network is switched to the mobile phone network when the reception level of the wireless LAN remains below the threshold for a predetermined period of time while the terminal is connected to the wireless LAN. In addition, the traffic during the communication is monitored, and the communication network is switched between the mobile phone network and the wireless LAN when the traffic is continuously suspended for a predetermined period of time. 
     With the conventional technique cited above, generally, once the connection is established at the communication network level, the communication network is switched irrespective of whether the connection has been completed at the application level. The communication network level refers to, for example, a transport layer or lower layers and the application level refers to an application layer, in the protocol stack of the transmission control protocol/internet protocol (TCP/IP). Accordingly, such a case may arise that the connection has not been completed at the application level despite the connection having been completed at the communication network level, and hence the application is unable to make communication until the connection is completed at the application level, or until switching to the communication network connected thus far or reconnection is completed after the failure in connection at the application level. Such a situation will be described in further detail, with respect to the case of switching the communication network from the mobile phone network to the wireless LAN, as an example. 
     When the portable terminal, which is already connected to the mobile phone network, attempts to connect to a backbone network via an access point and then to the internet or the like via a gateway, a predetermined procedure referred to as “association at network level” is performed between the portable terminal and the access point so as to allow the access point to recognize the presence of the portable terminal, in the wireless communication system based on Institute of Electrical and Electronics Engineers (IEEE) 802.11 Standard. 
     It is also a common practice that a procedure referred to as “authentication at application level” (for example, web authentication) is performed between the portable terminal and the gateway so as to allow the gateway to identify the user, so that only the portable terminal of the identified user is connected to the internet or the like. 
       FIG. 17  is a chart showing an operation sequence of the conventional wireless LAN communication system. 
     The portable terminal acquires from a target list an extended service set identifier (ESSID) of the network to which a connection is attempted, and broadcasts a probe request including the ESSID (step S 1700 ). 
     The access point returns a probe response when the ESSID in the received probe request is the same as its own ESSID or “ANY” (step S 1702 ). The probe response includes parameters such as a basic service set identifier (BSSID), an encryption method, an authentication method, and a communication rate of the access point. 
     When the portable terminal fails to receive the probe response, the portable terminal broadcast a probe request including another ESSID (step S 1700 ). 
     Upon receipt of the probe response, the portable terminal determines whether the BSSID included in the probe response is registered in an exclusion list. When the BSSID is registered in the exclusion list, the portable terminal broadcast a probe request including still another ESSID (step S 1700 ). 
     When the access point is not identified through the mentioned procedure, the portable terminal initializes the exclusion list (deletes the registered BSSID), and then repeats the mentioned procedure. 
     When the BSSID is not registered in the exclusion list, the portable terminal transmits an authentication request to the access point (step S 1704 ). 
     The access point determines whether the portable terminal may be authenticated using a predetermined algorithm, and returns an authentication response including the decision (step S 1706 ). Generally, the authentication is performed using the media access control (MAC) address of the portable terminal as an identifier. 
     Upon confirming the authentication by the access point, the portable terminal transmits an association (connection) request to the access point (step S 1708 ). The association request includes parameters such as the ESSID, a support report, and whether or not polling is necessary. 
     The access point returns an association response, upon confirming that the MAC address is the authenticated one and that all the parameters in the received association request correspond to the access point (step S 1710 ). 
     When the connection is established at the communication network level and the communication network is switched from the mobile phone network to the wireless LAN through the procedure described above, the portable terminal is enabled to connect to the backbone network via the access point and transmits a data frame. At this point, however, the user has not been authenticated by the gateway and the connection has not been completed at the application level, and therefore the portable terminal is unable to achieve connection to the internet or the like via the gateway. At this point, the connection to the mobile phone network may or may not be disconnected. 
     The portable terminal transmits a page acquisition request including the uniform resource locator (URL) of the log-in page, to the gateway (step S 1712 ). 
     The gateway returns the page corresponding to the URL in the page acquisition request, i.e., the log-in page (step S 1714 ). 
     The portable terminal transmits the authentication request to the gateway (step S 1716 ). The authentication request includes parameters such as the identification (ID) number of the user and a password. Such data may be automatically extracted from a setup file or manually inputted by the user. 
     The gateway transfers the received authentication request to an authentication server (step S 1718 ). 
     The authentication server determines whether the user may be authenticated on the basis of the ID and the password in the received authentication request, and returns the authentication response including the decision (step S 1720 ). 
     The gateway transfers the received authentication response to the portable terminal (step S 1722 ). 
     When the user is authenticated by the gateway and the connection is completed at the application level through the mentioned procedure, the portable terminal is enabled to connect to the internet or the like via the gateway, and transmit the connection request to the server (step S 1724 ). 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: Japanese Laid-open Patent Publication No. 2012-004659 
     SUMMARY 
     Technical Problem 
     With the conventional technique, convenience to users may be significantly impaired, as represented by the foregoing situation. 
     Accordingly, it is an object of the disclosed terminal and connection method for connecting the terminal that provide a solution to the problems incidental to the conventional technique. 
     Solution to Problem 
     According to an aspect of the terminal, there is provided a terminal which is capable of connecting to a communication network. The terminal includes a communication module for connecting to an access point of the communication network, a storage for storing a target list including networks to be connected, an exclusion list including an access point to be excluded from connection targets, and a duplicate exclusion list being a reproduction of the exclusion list, a connection controller for scanning the network registered in the target list, excluding the access point registered in the exclusion list from the detected access points so as to identify the access points to which a connection may be made, and a connection completion module for cutting off the connection to the access point and deleting the corresponding network from the target list, when it is detected that the connection to the access point registered in the duplicate exclusion list is started, wherein the connection controller identifies again the access points to which a connection may be made after initializing the exclusion list, when the access point to which a connection may be made is unable to be identified, and designating one of the identified access points to which a connection may be made as a target of the connection. 
     According to an aspect of the terminal, the connection completion module scans a given network, and registers a deleted network in the target list when the access point registered in the duplicate exclusion list is not detected. 
     According to an aspect of the terminal, the connection completion module does not scan a given network during a predetermined period of time when the deleted network is a predetermined network. 
     According to an aspect of the terminal, the terminal further includes a timer module for measuring time, wherein the connection completion module performs communication with the communication network a plurality of times so as to complete the connection to the communication network at an application level, causes the timer module to start clocking upon starting the connection to the communication network at the application level, and cuts off the connection to the access point upon determining, on the basis of the clocking of the timer module, that a predetermined timeout period has elapsed before completing the connection to the communication network at the application level. 
     According to an aspect of the terminal, the predetermined timeout period is specified according to the network which the access point in the communication network to which a connection has been established belongs to. 
     According to an aspect of the terminal, the terminal further includes a second communication module for connecting to a second communication network of a different type from the communication network, wherein the connection completion module completes connection to the communication network at an application level, and in cases in which connection to the second communication network is already completed, the connection controller notifies the connection completion module to the effect that the connection to the communication network has been established when such connection is established, and switches the network for communication from the second communication network to the communication network, upon receipt of a notice of completion of the connection to the communication network, from the connection completion module. 
     According to an aspect of the terminal, the storage further stores an access point which is a switching delay target, out of the access points in the communication network, and the connection controller immediately switches the network for communication from the second communication network to the communication network, when the access point of the communication network to which a connection is established is not the access point which is a switching delay target. 
     According to an aspect of the terminal, the connection controller allows communication with a server for completing the connection to the communication network to be performed through the communication network, in accordance with a request from the connection completion module. 
     According to an aspect of the terminal, the server performs user authentication of the terminal, and the connection to the communication network is completed when the user authentication by the server is completed. 
     According to an aspect of the connection method, there is provided a connection method to be executed by a terminal which is capable of connecting to a communication network, the terminal including a storage for storing a target list including networks to be connected, an exclusion list including an access point to be excluded from connection targets, and a duplicate exclusion list being a reproduction of the exclusion list. The method includes scanning a network registered in the target list, excluding the access point registered in the exclusion list from the detected access points so as to identify the access points to which a connection may be made, identifying again the access points to which a connection may be made after initializing the exclusion list, when the access point to which a connection may be made is unable to be identified, designating one of the identified access points to which a connection may be made as a target of the connection, and cutting off the connection to the access point and deleting the corresponding network from the target list, when it is detected that the connection to the access point registered in the duplicate exclusion list is started. 
     Advantageous Effects of Invention 
     The terminal and the connection method for connecting the terminal according provide solutions to the problems incidental to the conventional technique. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a view illustrating an example of the schematic configuration of a wireless communication system. 
         FIG. 2  is a view illustrating an example of the schematic configuration of a portable terminal. 
         FIG. 3  is a view indicating an example of the operation sequence of the wireless communication system. 
         FIG. 4  is a view illustrating an example of the schematic configuration of a portable terminal according to a second embodiment. 
         FIG. 5  is a view indicating an example of the operation sequence of the wireless communication system representing a success in connection to an access point. 
         FIG. 6  is a view indicating an example of the operation sequence of the wireless communication system representing a failure in connection to the access point. 
         FIG. 7  is a view indicating an example of the operation sequence of the wireless communication system representing a success in acquiring authentication through a gateway. 
         FIG. 8  is a view indicating an example of the operation sequence of the wireless communication system representing a failure in acquiring authentication through the gateway. 
         FIG. 9  is a view illustrating an example of the schematic configuration of a portable terminal according to a third embodiment. 
         FIG. 10  is a view indicating an example of the operation sequence of the wireless communication system representing a success in acquiring authentication through the gateway. 
         FIG. 11  is a view illustrating an example of the schematic configuration of a portable terminal according to a fourth embodiment. 
         FIG. 12  is a view indicating an example of the operation sequence of the wireless communication system. 
         FIG. 13  is a view indicating an example of another operation sequence of the wireless communication system. 
         FIG. 14  is a view illustrating an example of the schematic configuration of a portable terminal according to a fifth embodiment. 
         FIG. 15  is a view indicating an example of the operation sequence of the wireless communication system. 
         FIG. 16  is a view indicating an example of another operation sequence of the wireless communication system. 
         FIG. 17  is a view indicating an example of the operation sequence of a conventional wireless LAN communication system. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Various embodiments will be explained below with reference to the drawings. However, it should be noted that the technical scope of this application is not limited to the embodiments but includes the invention as defined by the claims and equivalents thereof. 
     (First Embodiment) 
     With the conventional technique, such a case may arise that the connection has not been completed at the application level despite the connection having been completed at the communication network level, and hence the application is unable to make communication until the connection or the like is completed at the application level. Therefore, convenience to users may be significantly impaired. 
     Accordingly, this embodiment attempts to eliminate an interruption period incidental to the switching of the communication network. To be more specific, in this embodiment a portable terminal is already connected to the mobile phone network and such a portable terminal attempts to make connection to the internet via a wireless LAN. In this process, the portable terminal obtains web authentication from a gateway, with respect to a predetermined access point. Only after the web authentication has succeeded (been completed), the portable terminal assumes that the connection to the wireless LAN has been established, and switches the communication network from the mobile phone network to the wireless LAN. 
       FIG. 1  is a view illustrating an example of the schematic configuration of a wireless communication system  1 . 
     The wireless communication system  1  includes a portable terminal  2  capable of making connection to the wireless LAN and the mobile phone network, an access point  3  of the wireless LAN, and a base station  9  of the mobile phone network. The portable terminal  2  is capable of performing wireless communication with the access point  3  and the base station  9  within their service area. 
     The access point  3  is connected to a backbone network  4 . A gateway  5  intermediating between the backbone network  4  and the internet  7 , and an authentication server  6  that authenticates users are connected to the backbone network  4 , via a wired LAN such as Ethernet (registered trademark). 
     The portable terminal  2  can be connected to the internet  7  via the gateway  5 , when the user is authenticated by the authentication server  6  through the gateway  5 . Accordingly, the portable terminal  2  can communicate with a server  8  connected to the internet  7 . 
     The base station  9  is connected to the mobile phone network  10 . A gateway  5 - 1  intermediating between the mobile phone network  10  and the internet  7  is connected to the mobile phone network  10 . 
     The portable terminal  2  can also be connected to the internet  7  via the gateway  5 - 1 . Accordingly, the portable terminal  2  can communicate with the server  8  connected to the internet  7 . 
       FIG. 2  is a view illustrating an example of the schematic configuration of the portable terminal  2 . 
     The portable terminal  2  makes connection to the server  8  via the access point  3 , the backbone network  4 , the gateway  5 , and the internet  7 , or via the base station  9 , the mobile phone network  10 , the gateway  5 - 1 , and the internet  7 , and communicates with the server  8 . For such purpose, the portable terminal  2  includes a first communication unit  21 , a second communication unit  22 , a storage unit  23 , an operation unit  24 , a display unit  25 , and a processing unit  26 . 
     The first communication unit  21  includes a communication interface circuit including an antenna mainly sensitive to a 2.4 GHz band, and serves to connect the portable terminal  2  to the backbone network  4 . The first communication unit  21  establishes a wireless communication line with the access point  3  based on the wireless communication method according to IEEE 802.11 Standard, to thereby communicate with the access point  3 . The first communication unit  21  provides data received from the access point  3  to the processing unit  26 . The first communication unit  21  also transmits data provided from the processing unit  26  to the access point  3 . 
     The second communication unit  22  includes a communication interface circuit including an antenna mainly sensitive to a 2 GHz band, and serves to connect the portable terminal  2  to the mobile phone network  10 . The second communication unit  22  establishes a wireless signal line with the base station  9  according to the code division multiple access (CDMA) method or the like, through a channel assigned by the base station  9 , to thereby communicate with the base station  9 . The second communication unit  22  provides data received from the base station  9  to the processing unit  26 . The second communication unit  22  also transmits data provided from the processing unit  26  to the base station  9 . 
     The storage unit  23  includes at least one of, for example, a semiconductor memory, a magnetic disk device, and an optical disk device. The storage unit  23  stores therein a driver program, an operating system program, an application program, data, and the like used for the processing in the processing unit  26 . Examples of the driver program stored in the storage unit  23  include an input device driver program for controlling the operation unit  24 , and an output device driver program for controlling the display unit  25 . An example of the operating system program stored in the storage unit  23  is a connection control program for executing the wireless communication based on IEEE 802.11 Standard. Examples of the application program stored in the storage unit  23  include an authentication program for executing web authentication, a web browser program for acquiring and displaying web pages, and an e-mail program for transmitting and receiving e-mails. Examples of the data stored in the storage unit  23  include a target list including the ESSID of the network to be connected, an exclusion list including the BSSID of an excluded access point  3 , the BSSID of the access point  3  to which a connection is in process or already completed and the ESSID corresponding thereto, the ESSID of the network to be authenticated, a setup file including details of settings regarding the network connection, picture data, and image data. The storage unit  23  may also temporarily store transitory data related to a predetermined process. 
     The operation unit  24  may be constituted of any device provided that the device is capable of operating the portable terminal  2 , and is typically exemplified by a touch pad and a keyboard. The user can input characters, numerals, or the like through the device. The operation unit  24  generates, upon being operated by the user, a signal corresponding to the operation. The signal thus generated is inputted to the processing unit  26  as an instruction of the user. 
     The display unit  25  may also be constituted of any device provided that the device is capable of displaying pictures, images, or the like and is typically exemplified by a liquid crystal display and an organic electro-luminescence (EL) display. The display unit  25  displays pictures corresponding to the picture data provided from the processing unit  26 , and images or the like corresponding to the image data provided therefrom. 
     The processing unit  26  includes one or a plurality of processors, and peripheral circuits thereof. The processing unit  26  performs centralized control of the overall operation of the portable terminal  2 , and is constituted of, for example, a central processing unit (CPU). More specifically, the processing unit  26  controls the operation of the first communication unit  21 , the second communication unit  22 , the display unit  25 , or the like, so as to allow the processes of the portable terminal  2  to be executed through appropriate procedures in accordance with the programs stored in the storage unit  23 , the instructions from the operation unit  24 , or the like. The processing unit  26  executes the processes in accordance with the programs stored in the storage unit  23  (driver program, operating system program, application program, and so forth). The processing unit  26  is capable of executing a plurality of programs (for example, application programs) in parallel. 
     The processing unit  26  includes an authentication unit  261 , an operating system  262 , a connection control unit  263 , and a wireless LAN connection control unit  264 . These units are functional modules implemented by the program executed on the processor in the processing unit  26 . Alternatively, the cited units may be implemented in the portable terminal  2  in the form of firmware. 
     The authentication unit  261  notifies the ESSID of the network to be authenticated, to the connection control unit  263 . The authentication unit  261  also notifies the start and finish of the web authentication to the connection control unit  263 . In addition, the authentication unit  261  executes web authentication with the gateway  5 . Details of such operations will be subsequently described. 
     The operating system  262  realizes basic functions utilized in common by the applications and controls the overall operation of the portable terminal  2 , and is typically exemplified by Android (registered trademark) OS and iOS (registered trademark). The operating system  262  relays the notices related to the web authentication between the authentication unit  261  and the connection control unit  263 . 
     The connection control unit  263  switches the communication network between the mobile phone network  10  and the wireless LAN. The connection control unit  263  also sets a communication channel for a predetermined internet protocol (IP) address. Details of such operations will be subsequently described. 
     The wireless LAN connection control unit  264  executes the wireless communication in compliance with IEEE 802.11 Standard. The wireless LAN connection control unit  264  also notifies start and establishment of the connection to the access point  3 , to the authentication unit  261  and the connection control unit  263 . Further, the wireless LAN connection control unit  264  cuts off the connection to the access point  3 . Details of such operations will be subsequently described. 
     Hereinafter, the operation of the wireless LAN connection control unit  264  will be described. 
     Upon detecting that connection to the wireless LAN has been turned ON, the wireless LAN connection control unit  264  acquires an ESSID from the target list stored in the storage unit  23 , and broadcasts a probe request including the acquired ESSID through the first communication unit  21 . 
     When a probe response is not received from the access point  3  through the first communication unit  21 , the wireless LAN connection control unit  264  acquires another ESSID from the target list stored in the storage unit  23 , and broadcasts the probe request including the acquired ESSID through the first communication unit  21 . On the other hand, when the probe response is received from the access point  3  through the first communication unit  21 , the wireless LAN connection control unit  264  determines whether the BSSID included in the received probe response is registered in the exclusion list stored in the storage unit  23 . When the BSSID is registered in the exclusion list, the wireless LAN connection control unit  264  acquires still another ESSID from the target list stored in the storage unit  23 , and broadcasts the probe request including the acquired ESSID through the first communication unit  21 . When the access point  3  is not identified through the mentioned procedure, the wireless LAN connection control unit  264  repeats the same procedure after initializing the exclusion list. On the other hand, when the BSSID is not registered in the exclusion list, the BSSID and the corresponding ESSID are stored in the storage unit  23 . The wireless LAN connection control unit  264  transmits an authentication request to the access point  3  through the first communication unit  21 . The wireless LAN connection control unit  264  also notifies the authentication unit  261  and the connection control unit  263  to the effect that connection to the access point  3  has been started. 
     Upon receipt of an authentication response from the access point  3  through the first communication unit  21 , the wireless LAN connection control unit  264  confirms the authentication of the access point  3  and then transmits an association request to the access point  3  through the first communication unit  21 . The wireless LAN connection control unit  264  then notifies, upon receipt of an association response from the access point  3  through the first communication unit  21 , the authentication unit  261  and the connection control unit  263  to the effect that connection to the access point  3  has been established. 
     When a request for disconnection from access point  3  is received from the connection control unit  263 , the wireless LAN connection control unit  264  cuts off the connection to the access point  3 , which is in process or already completed. 
     Hereinafter, the operation of the connection control unit  263  will be described. 
     When the authentication unit  261  requests setting of the network to be authenticated using the ESSID or the like as parameter, the connection control unit  263  stores the received ESSID in the storage unit  23 . 
     Upon receipt of the notice from the wireless LAN connection control unit  264  to the effect that the connection to the access point  3  has been established, the connection control unit  263  acquires the ESSID of the access point  3  to which a connection is in process or already completed, from the storage unit  23 . The connection control unit  263  also looks up the ESSID of the network to be authenticated stored in the storage unit  23 , and determines whether the acquired ESSID is included. When the acquired ESSID is not included, the connection control unit  263  switches the communication network from the mobile phone network  10  to the wireless LAN. When the acquired ESSID is included, the connection control unit  263  continues with the current process. 
     Upon receipt of the notice from the authentication unit  261  to the effect that the web authentication is started, the connection control unit  263  allows the authentication unit  261  to communicate with a non-illustrated domain name system (DNS) server through the wireless LAN. 
     When the authentication unit  261  requests setting of a communication channel using the IP address or the like as parameter, the connection control unit  263  sets a channel that allows the authentication unit  261  to communicate with the host of the received IP address through the wireless LAN. 
     Upon receipt of the notice from the authentication unit  261  to the effect that the web authentication has been finished, with the authentication result or the like as parameter, the connection control unit  263  allows the authentication unit  261  to communicate with the non-illustrated DNS server through a default communication channel (mobile phone network  10 ). 
     The connection control unit  263  determines whether the web authentication is successful (completed), on the basis of the received authentication result. When the web authentication is successful, the connection control unit  263  switches the communication network from the mobile phone network  10  to the wireless LAN. When the web authentication fails, the connection control unit  263  requests the wireless LAN connection control unit  264  to cut off the connection to the access point  3 . Accordingly, the mobile phone network  10  is continuously used as the communication network. 
     Hereinafter, the operation of the authentication unit  261  will be described. 
     Upon detecting that the switching delay mode has been turned ON, the authentication unit  261  looks up the setup file stored in the storage unit  23 , and extracts the ESSID of the network to be authenticated. The authentication unit  261  also requests the connection control unit  263  to set the network to be authenticated using the extracted ESSID or the like as parameter. 
     Upon receipt of the notice from the wireless LAN connection control unit  264  to the effect that the connection to the access point  3  has been established, the authentication unit  261  notifies the connection control unit  263  to the effect that the web authentication is started. 
     The authentication unit  261  looks up the setup file stored in the storage unit  23 , and extracts the IP address of the gateway  5 . Alternatively, the authentication unit  261  may look up the setup file stored in the storage unit  23  so as to extract the URL of the gateway  5 , and make an inquiry to the non-illustrated DNS server through the first communication unit  21 , thus acquiring the corresponding IP address. The authentication unit  261  then requests the connection control unit  263  to set the communication channel, using the extracted or acquired IP address or the like as parameter. 
     The authentication unit  261  transmits a page acquisition request including the URL of the log-in page to the gateway  5  through the first communication unit  21 . 
     Upon receipt of the log-in page from the gateway  5  through the first communication unit  21 , the authentication unit  261  looks up the setup file stored in the storage unit  23 , to thereby extract the user ID and the password. The authentication unit  261  then transmits the authentication request including the extracted ID and password to the gateway  5  through the first communication unit  21 . 
     Upon receipt of the authentication response from the gateway  5  through the first communication unit  21 , the authentication unit  261  extracts the authentication result from the received authentication response, and notifies the connection control unit  263  to the effect that the web authentication has been finished, using the extracted authentication result or the like as parameter. 
       FIG. 3  is a view indicating an example of the operation sequence of the wireless communication system  1 . The operation sequence described Hereinafter is performed primarily by the processing unit  26  or the like in collaboration with the portable terminal  2 , the access point  3 , and the gateway  5 , on the basis of the programs stored in advance in the storage unit  23  or the like. Out of the following operation sequence, steps S 1702  to  1710 , and steps  1714  to  1724  are the same as those included in  FIG. 17 , and therefore the description of those steps will not be repeated. 
     Upon detecting that the switching delay mode has been turned ON, the authentication unit  261  looks up the setup file stored in the storage unit  23 , and extracts the ESSID of the network to be authenticated. The authentication unit  261  also requests the connection control unit  263  to set the network to be authenticated using the extracted ESSID or the like as parameter (step S 300 ). 
     When the authentication unit  261  requests setting of the network to be authenticated using the ESSID or the like as parameter, the connection control unit  263  stores the received ESSID in the storage unit  23  (step S 302 ). 
     Upon detecting that connection to the wireless LAN has been turned ON, the wireless LAN connection control unit  264  acquires an ESSID from the target list stored in the storage unit  23 , and broadcasts the probe request including the acquired ESSID through the first communication unit  21  (step S 1700 ). 
     Upon receipt of the association response from the access point  3  through the first communication unit  21 , the wireless LAN connection control unit  264  notifies the authentication unit  261  and the connection control unit  263  to the effect that connection to the access point  3  has been established (step S 304 ). 
     Upon receipt of the notice from the wireless LAN connection control unit  264  to the effect that the connection to the access point  3  has been established, the connection control unit  263  acquires the ESSID of the access point  3  to which a connection is in process or already completed, from the storage unit  23 . The connection control unit  263  also looks up the ESSID of the network to be authenticated stored in the storage unit  23 , and determines whether the acquired ESSID is included (step S 306 ). 
     When the acquired ESSID is not included (No at step S 306 ), the connection control unit  263  switches the communication network from the mobile phone network  10  to the wireless LAN (step S 308 ). 
     When the acquired ESSID is included (Yes at step S 306 ), the connection control unit  263  continues with the current process. 
     Upon receipt of the notice from the wireless LAN connection control unit  264  to the effect that the connection to the access point  3  has been established, the authentication unit  261  notifies the connection control unit  263  to the effect that the web authentication is started (step S 310 ). 
     Upon receipt of the notice from the authentication unit  261  to the effect that the web authentication is started, the connection control unit  263  allows the authentication unit  261  to communicate with the non-illustrated DNS server through the wireless LAN. 
     The authentication unit  261  looks up the setup file stored in the storage unit  23 , and extracts the IP address of the gateway  5 . Alternatively, the authentication unit  261  may look up the setup file stored in the storage unit  23  so as to extract the URL of the gateway  5 , and make an inquiry to the non-illustrated DNS server through the first communication unit  21 , thus acquiring the corresponding IP address. The authentication unit  261  then requests the connection control unit  263  to set the communication channel, using the extracted or acquired IP address or the like as parameter (step S 312 ). 
     When the authentication unit  261  requests setting of the communication channel using the IP address or the like as a parameter, the connection control unit  263  allows the authentication unit  261  to communicate with the host of the received IP address through the wireless LAN (step S 314 ). 
     The authentication unit  261  transmits the page acquisition request including the URL of the log-in page to the gateway  5  through the first communication unit  21  (step S 1712 ). 
     Upon receipt of the authentication response from the gateway  5  through the first communication unit  21 , the authentication unit  261  extracts the authentication result from the received authentication response, and notifies the connection control unit  263  to the effect that the web authentication has been finished, using the extracted authentication result or the like as parameter (step S 316 ). 
     Upon receipt of the notice from the authentication unit  261  to the effect that the web authentication has been finished, with the authentication result or the like as parameter, the connection control unit  263  allows the authentication unit  261  to communicate with the non-illustrated DNS server through a default communication channel. 
     The connection control unit  263  determines whether the web authentication has succeeded, on the basis of the received authentication result (step S 318 ). 
     When the web authentication is successful (Yes at step S 318 ), the connection control unit  263  switches the communication network from the mobile phone network  10  to the wireless LAN (step S 320 ). 
     When the web authentication fails (No at step S 318 —No), the connection control unit  263  requests the wireless LAN connection control unit  264  to cut off the connection to the access point  3  (step S 322 ). 
     Upon receipt of the request to cut off the connection to the access point  3  from the connection control unit  263 , the wireless LAN connection control unit  264  cuts off the connection to the access point  3 , which is in process or already completed (step S 324 ). 
     As described thus far, the interruption period incidental to the switching of the communication network can be eliminated by switching the communication network in accordance with the notice from the application. 
     The present invention is not limited to this embodiment. For example, although the communication network is switched from the mobile phone network  10  to the wireless LAN in this embodiment, the communication network may be switched reversely. Further, the connection method of this embodiment may be applied to a combination of different types (wired or wireless) of communication networks. 
     In this embodiment, the network to be authenticated is set when the activation of the switching delay mode is detected; however a different trigger may be adopted. For example, the setting of the network to be authenticated may be triggered by the activation of the portable terminal  2 , or updating of the setup file. In addition, the network to be authenticated that has been set may be deleted when turning off of the switching delay mode is detected, or when the portable terminal  2  is turned off. Such arrangements assure the setting of the network to be authenticated, and enable effective utilization of resources such as a memory. 
     Although the application related to the switching delay of the communication network is exemplified by the web authentication in this embodiment, a different application may be associated with the switching delay. In this case, the communication can be performed under various communication environments or the like. 
     Although the web authentication is performed through the wireless LAN in this embodiment, the web authentication may be performed through the mobile phone network  10 . In this case, the authentication unit  261  may skip expressly requesting the connection control unit  263  to set up the communication channel. Such an arrangement allows the communication to be performed under various communication environments or the like. 
     Further, the connection control unit  263  may measure the time between the notice to the effect that the connection to the access point  3  has been established and the notice to the effect that the web authentication has been completed, and cut off the connection to the access point  3  when a predetermined timeout period elapses. Such an arrangement allows the resources such as the CPU, the memory, the network, or the like to be effectively utilized. 
     Further, the authentication unit  261  may measure the time between the transmission of the page acquisition request and the receipt of the authentication response, and cut off the connection to the access point  3  when a predetermined timeout period elapses, and also register the access point  3  in the exclusion list (black list) so as to exclude the access point  3  from the connection target. Such an arrangement prevents reconnection to an invalid access point  3 . 
     Further, the portable terminal  2  may cancel display of a pictogram and an accompanying message indicating that the web authentication is in process, taking into account that, while the portable terminal  2  is operating in the switching delay mode, other applications can also perform communication through the mobile phone network  10  even when the authentication unit  261  is performing the web authentication. Likewise, the portable terminal  2  may display a pictogram indicating that connection to the wireless LAN has been established, after the web authentication is completed. The mentioned arrangement minimizes complexity of the display. 
     Still further, the computer programs for allowing a computer to realize the functions of the processing unit  26  may be provided in the form of a computer-readable recording medium, such as a magnetic recording medium or an optical recording medium. 
     (Second Embodiment) 
     In general, a timeout program is incorporated in data processing, communication, and so forth. The timeout program refers to an arrangement to forcibly finish the data processing or communication when the time being spent for the data processing or communication exceeds a predetermined time (hereinafter, “timeout period”), for example because of no response from a server, to thereby release the resources such as a central processing unit (CPU) and a network that have been occupied. Generally, the time required for the data processing, communication, or the like is measured from the time that a request for the data processing, communication, or the like is made up to the time that the response is received. The timeout program is incorporated, for example, in the protocol of the transport layer, the application layer, or the like in the protocol stack of the transmission control protocol/internet protocol (TCP/IP) (see, for example, Japanese Laid-open Patent Publication No. 2010-187070 and Japanese Laid-open Patent Publication No. 2008-098804). 
     However, the time required for the data processing, communication, or the like varies depending on the processing capacity of the server, communication capacity of the network, or the like, and hence the timeout period is generally set with a certain allowance. Accordingly, the user may be forced to wait a long time before receiving a response to the request for the data processing, communication, or the like, or before the timeout is applied to the data processing, communication, or the like, depending on the processing capacity of the server, communication capacity of the network, or the like. 
     In particular, the inconvenience is serious when the communication is performed a plurality of times to complete a process, such as a connection process and a transaction process. Assuming that, for example, communication is performed n times to complete a process and the timeout period of each session of the communication is t minutes, the user may be forced to wait n×t minutes in a worst-case situation. Therefore, with the conventional timeout program the convenience to the user may be significantly impaired. 
     Accordingly, this embodiment attempts to lower an upper limit of the time required for a process in which communication is performed a plurality of times. More specifically, in this embodiment the portable terminal is connected to the Internet through the wireless LAN. In this process, the portable terminal communicates a plurality of times with each of the access point and the gateway, before the connection is established or completed. The timeout period is specified with respect to the time required for the plurality of times of communication, and when the timeout period elapses the portable terminal cuts off the connection to the access point, which is in process or already completed. 
       FIG. 4  is a view illustrating an example of the schematic configuration of a portable terminal  2 - 1 . In this configuration, the first communication unit  21 , the second communication unit  22 , the operation unit  24 , the display unit  25 , the operating system  262 , and the connection control unit  263  are the same as those depicted in  FIG. 2 , and therefore the description thereof will not be repeated. 
     The storage unit  23 - 1  stores therein a clocking program or the like as one of the application programs, in addition to the programs stored in the storage unit  23  depicted in  FIG. 2 . The storage unit  23 - 1  also stores, as the data, the user ID and the password, the timeout period specified for the time required for the communication with the access point  3 , and the timeout period or the like specified for the time required for the communication with the gateway  5 . 
     The authentication unit  261 - 1  performs the web authentication with the gateway  5 . The authentication unit  261 - 1  also requests the wireless LAN connection control unit  264 - 1  to cut off the connection to the access point  3 . Further, the authentication unit  261 - 1  instructs a timer unit  265  to start or finish clocking. Details of such operations will be subsequently described. 
     The wireless LAN connection control unit  264 - 1  executes the wireless communication in compliance with IEEE 802.11 Standard. The wireless LAN connection control unit  264 - 1  also notifies the connection status with respect to the access point  3 , to the authentication unit  261 - 1 . Further, the wireless LAN connection control unit  264 - 1  cuts off the connection to the access point  3 . Details of such operations will be subsequently described. 
     The timer unit  265  measures the time. To be more detailed, the timer unit  265  resets the clock and starts to measure the time upon receipt of an instruction to start clocking, and finishes clocking upon receipt of an instruction to finish clocking, using a predetermined time as argument. When the predetermined time specified as argument elapses before receipt of the instruction to finish clocking, the timer unit  265  notifies the authentication unit  261 - 1  to that effect. Further, upon receipt of an instruction to make decision regarding the lapse of time, the timer unit  265  determines whether the predetermined time specified as argument has elapsed, and returns the decision. 
     Hereinafter, the operation of the wireless LAN connection control unit  264 - 1  will be described. 
     Upon detecting that connection to the wireless LAN has been turned ON, the wireless LAN connection control unit  264 - 1  acquires an ESSID from the target list stored in the storage unit  23 - 1 , and broadcasts the probe request including the ESSID through the first communication unit  21 . 
     When the probe response is not received from the access point  3  through the first communication unit  21 , the wireless LAN connection control unit  264 - 1  acquires another ESSID from the target list stored in the storage unit  23 - 1 , and broadcasts the probe request including the ESSID through the first communication unit  21 . On the other hand, when the probe response is received from the access point  3  through the first communication unit  21 , the wireless LAN connection control unit  264 - 1  determines whether the BSSID included in the probe response is registered in the exclusion list stored in the storage unit  23 - 1 . When the BSSID is registered in the exclusion list, the wireless LAN connection control unit  264 - 1  acquires still another ESSID from the target list stored in the storage unit  23 - 1 , and broadcasts the probe request including the ESSID through the first communication unit  21 . When the access point  3  is not identified through the mentioned procedure, the wireless LAN connection control unit  264 - 1  repeats the same procedure after initializing the exclusion list. On the other hand, when the BSSID is not registered in the exclusion list, the BSSID and the corresponding ESSID are stored in the storage unit  23 - 1 . The wireless LAN connection control unit  264 - 1  transmits the authentication request to the access point  3  through the first communication unit  21 . The wireless LAN connection control unit  264 - 1  also notifies the authentication unit  261 - 1  to the effect that connection to the access point  3  has been started. 
     Upon receipt of the authentication response from the access point  3  through the first communication unit  21 , the wireless LAN connection control unit  264 - 1  confirms the authentication of the access point  3  and then transmits the association request to the access point  3  through the first communication unit  21 . The wireless LAN connection control unit  264 - 1  then notifies, upon receipt of the association response from the access point  3  through the first communication unit  21 , the authentication unit  261 - 1  to the effect that connection to the access point  3  has been established. 
     When the request for disconnection from access point  3  is received from the authentication unit  261 - 1 , the wireless LAN connection control unit  264 - 1  cuts off the connection to the access point  3 , which is in process or already completed. 
     Hereinafter, the operation of the authentication unit  261 - 1  will be described. 
     Upon receipt of the notice from the wireless LAN connection control unit  264 - 1  to the effect that the connection to the access point  3  has been started, the authentication unit  261 - 1  acquires from the storage unit  23 - 1  the timeout period specified for the time required for communication with the access point  3 , and instructs the timer unit  265  to start clocking using the timeout period as argument. 
     Upon receipt of the notice from the timer unit  265  to the effect that the timeout period given as argument has elapsed, the authentication unit  261 - 1  requests the wireless LAN connection control unit  264 - 1  to cut off the connection to the access point  3 . 
     Upon receipt of the notice from the wireless LAN connection control unit  264 - 1  to the effect that the connection to the access point  3  has been established, the authentication unit  261 - 1  instructs the timer unit  265  to finish clocking. The authentication unit  261 - 1  also transmits the page acquisition request to the gateway  5  through the first communication unit  21 . Further, the authentication unit  261 - 1  acquires from the storage unit  23 - 1  the timeout period specified for the time required for communication with the gateway  5 , and instructs the timer unit  265  to start clocking using the timeout period as argument. 
     Upon receipt of the notice from the timer unit  265  to the effect that the timeout period given as argument has elapsed, the authentication unit  261 - 1  requests the wireless LAN connection control unit  264 - 1  to cut off the connection to the access point  3 . 
     Upon receipt of the log-in page from the gateway  5  through the first communication unit  21 , the authentication unit  261 - 1  acquires the user ID and the password from the storage unit  23 - 1 , and transmits the authentication request including the ID and the password to the gateway  5  through the first communication unit  21 . Further, upon receipt of the authentication response from the gateway  5  through the first communication unit  21 , the authentication unit  261 - 1  instructs the timer unit  265  to stop clocking, irrespective of whether the user has been authenticated by the gateway  5 . 
       FIG. 5  is a view indicating an example of the operation sequence of the wireless communication system  1  representing a success in connection to the access point  3 . 
     Upon detecting that connection to the wireless LAN has been turned ON, the wireless LAN connection control unit  264 - 1  acquires an ESSID from the target list stored in the storage unit  23 - 1 , and broadcasts the probe request including the ESSID through the first communication unit  21  (step S 1700 ). 
     The access point  3  returns the probe response when the ESSID in the received probe request is the same as its own ESSID or “ANY” (step S 1702 ). 
     When the probe response is not received from the access point  3  through the first communication unit  21 , the wireless LAN connection control unit  264 - 1  acquires another ESSID from the target list stored in the storage unit  23 - 1 , and broadcasts the probe request including the ESSID through the first communication unit  21  (step S 1700 ). 
     On the other hand, when the probe response is received from the access point  3  through the first communication unit  21 , the wireless LAN connection control unit  264 - 1  determines whether the BSSID included in the probe response is registered in the exclusion list stored in the storage unit  23 - 1 . When the BSSID is registered in the exclusion list, the wireless LAN connection control unit  264 - 1  acquires still another ESSID from the target list stored in the storage unit  23 - 1 , and broadcasts the probe request including the ESSID through the first communication unit  21  (step S 1700 ). 
     When the access point  3  is unable to be identified through the steps S 1700  to  1702 , the wireless LAN connection control unit  264 - 1  repeats the steps S 1700  to  1702  after initializing the exclusion list. 
     On the other hand, when the BSSID is not registered in the exclusion list, the wireless LAN connection control unit  264 - 1  stores the BSSID and the corresponding ESSID in the storage unit  23 - 1 . The wireless LAN connection control unit  264 - 1  also transmits the authentication request to the access point  3  through the first communication unit  21  (step S 1704 ). 
     The wireless LAN connection control unit  264 - 1  notifies the authentication unit  261 - 1  to the effect that connection to the access point  3  has been started (step S 500 ). 
     Upon receipt of the notice from the wireless LAN connection control unit  264 - 1  to the effect that the connection to the access point  3  has been started, the authentication unit  261 - 1  acquires from the storage unit  23 - 1  the timeout period specified for the time required for communication with the access point  3 , and instructs the timer unit  265  to start clocking using the timeout period as argument (step S 502 ). 
     Upon receipt of the authentication request from the portable terminal  2 - 1 , the access point  3  determines whether the portable terminal  2 - 1  may be authenticated using a predetermined algorithm, and returns an authentication response including the decision (step S 1706 ). 
     Upon receipt of the authentication response from the access point  3  through the first communication unit  21 , the wireless LAN connection control unit  264 - 1  confirms the authentication of the access point  3 , and then transmits the association request to the access point  3  through the first communication unit  21  (step S 1708 ). 
     The access point  3  returns the association response, upon confirming that the MAC address is the authenticated one and that all the parameters in the received association request correspond to the access point  3  (step S 1710 ). 
     Upon receipt of the association response from the access point  3  through the first communication unit  21 , the wireless LAN connection control unit  264 - 1  notifies the authentication unit  261 - 1  to the effect that connection to the access point  3  has been established (step S 504 ). 
     Upon receipt of the notice from the wireless LAN connection control unit  264 - 1  to the effect that the connection to the access point  3  has been established, the authentication unit  261 - 1  instructs the timer unit  265  to finish clocking (step S 506 ). 
       FIG. 6  is a view indicating an example of the operation sequence of the wireless communication system  1  representing a failure in making connection to the access point  3 . Out of the following operation sequence, steps S 1700  to  1704  and steps  500 ,  502  are the same as those included in  FIG. 5 , and therefore the description of those steps will not be repeated. 
     Upon receipt of the notice from the timer unit  265  to the effect that the timeout period given as argument has elapsed (Yes at step S 508 ), the authentication unit  261 - 1  requests the wireless LAN connection control unit  264 - 1  to cut off the connection to the access point  3  (step S 510 ). 
     When the request for disconnection from access point  3  is received from the authentication unit  261 - 1 , the wireless LAN connection control unit  264 - 1  cuts off the connection to the access point  3  which is in process (step S 512 ). 
       FIG. 7  is a view indicating an example of the operation sequence of the wireless communication system  1  representing a success in acquiring the authentication through the gateway  5 . Out of the following operation sequence, steps S 1700  to  1710 , and steps S 500  to  506  are the same as those included in  FIG. 5 , and therefore the description of those steps will not be repeated. 
     The authentication unit  261 - 1  transmits the page acquisition request to the gateway  5  through the first communication unit  21  (step S 1712 ). 
     The authentication unit  261 - 1  acquires from the storage unit  23 - 1  the timeout period specified for the time required for communication with the gateway  5 , and instructs the timer unit  265  to start clocking using the timeout period as argument (step S 516 ). 
     The gateway  5  returns the page corresponding to the URL in the received page acquisition request, i.e., the log-in page (step S 1714 ). 
     Upon receipt of the log-in page from the gateway  5  through the first communication unit  21 , the authentication unit  261 - 1  acquires the user ID and the password from the storage unit  23 - 1 , and transmits the authentication request including the ID and the password to the gateway  5  through the first communication unit  21  (step S 1716 ). 
     The gateway  5  transfers the received authentication request to the authentication server  6 . The gateway  5  also transfers the received authentication response to the portable terminal  2 - 1  (step S 1722 ). 
     Upon receipt of the authentication response from the gateway  5  through the first communication unit  21 , the authentication unit  261 - 1  instructs the timer unit  265  to stop clocking, irrespective of whether the user has been authenticated by the gateway  5  (step S 518 ). 
       FIG. 8  is a view indicating an example of the operation sequence of the wireless communication system  1  representing a failure in acquiring the authentication through the gateway  5 . Out of the following operation sequence, steps S 1700  to  1712 , steps S 500  to  506 , and step S 516  are the same as those included in  FIG. 5  and  FIG. 7 , and therefore the description of the steps will not be repeated. 
     Upon receipt of the notice from the timer unit  265  to the effect that the timeout period given as argument has elapsed (Yes at step S 520 ), the authentication unit  261 - 1  requests the wireless LAN connection control unit  264 - 1  to cut off the connection to the access point  3  (step S 522 ). 
     When the request for disconnection from access point  3  is received from the authentication unit  261 - 1 , the wireless LAN connection control unit  264 - 1  cuts off the connection to the access point  3 , which is already completed (step S 524 ). 
     As described thus far, the upper limit of the time required for a process can be lowered, by cumulatively measuring the time required for a plurality of times of communication, and forcibly disconnecting the communication, when the predetermined timeout period elapses, before the plurality of times of communication is finished. 
     The present invention is not limited to this embodiment. For example, although only one gateway is provided in this embodiment, a plurality of gateways may be provided. Applying the present embodiment to each of the gateways allows the upper limit of the time required for communication with each gateway to be lowered, thereby enabling, consequently, the upper limit of the time required for communication with all the gateways, to which the present embodiment is applied, to be lowered. 
     (Third Embodiment) 
     In the second embodiment, the same timeout period is specified for the time required for communication with the gateway  5 , irrespective of the network (ESSID). However, normally the time required for communication with the gateway  5  is different depending on the network. Accordingly, different timeout periods are specified for different networks, in this embodiment. 
       FIG. 9  is a view illustrating an example of the schematic configuration of a portable terminal  2 - 2 . In this configuration, the first communication unit  21 , the second communication unit  22 , the operation unit  24 , the display unit  25 , the operating system  262 , the connection control unit  263 , the wireless LAN connection control unit  264 - 1 , and the timer unit  265  are the same as those depicted in  FIG. 4 , and therefore the description thereof will not be repeated. 
     The storage unit  23 - 2  stores therein, as the data, a table including the BSSID of the networks to be connected and the corresponding timeout periods, in addition to the data stored in the storage unit  23 - 1  depicted in  FIG. 4 . 
     The authentication unit  261 - 2  performs the web authentication with the gateway  5 . The authentication unit  261 - 2  also requests the wireless LAN connection control unit  264 - 1  to cut off the connection to the access point  3 . The authentication unit  261 - 2  also instructs a timer unit  265  to start or finish clocking. Further, the authentication unit  261 - 2  specifies a different timeout period for each network. To be more detailed, the authentication unit  261 - 2  acquires from the storage unit  23 - 2  the ESSID of the network to which a connection is already completed, after transmitting the page acquisition request to the gateway  5  through the first communication unit  21 , and looks up the table stored in the storage unit  23 - 2  using the ESSID as key, to thereby extract the corresponding timeout period. In addition, the authentication unit  261 - 2  instructs the timer unit  265  to start clocking using the timeout period as argument. 
       FIG. 10  is a view indicating an example of the operation sequence of the wireless communication system  1  representing a success in acquiring the authentication through the gateway  5 . Out of the following operation sequence, steps S 1700  to  1722 , steps S 500  to  506 , and step S 518  are the same as those included in  FIG. 5  and  FIG. 7 , and therefore the description of those steps will not be repeated. 
     The authentication unit  261 - 2  acquires from the storage unit  23 - 2  the ESSID of the network to which a connection is already completed, and looks up the table stored in the storage unit  23 - 2  using the ESSID as key, to thereby extract the corresponding timeout period. In addition, the authentication unit  261 - 2  instructs the timer unit  265  to start clocking using the timeout period as argument (step S 1000 ). 
     As described above, specifying predetermined timeout periods for different networks allows the upper limit of the time required for a process to be more effectively lowered. 
     The present invention is not limited to this embodiment. For example, although the timeout period is specified for each network (ESSID) in this embodiment, the timeout period may be specified for each access point (BSSID). Such an arrangement allows the upper limit of the time required for a process to be even more effectively lowered. 
     Further, the timeout period may be changed by the user or the system, by modifying the setup file or the like. Such an arrangement allows the communication to be performed under various communication environments or the like. 
     (Fourth Embodiment) 
     In the exclusion list, the access points desired to be excluded from the connection targets are registered. When an application or the like registers the access point desired to be excluded from the connection targets for some reason (for example, the connection takes time, the communication rate is too low, and so forth), such an access point is automatically excluded from the connection targets through the procedure specified in  FIG. 17 . 
     With the procedure specified in  FIG. 17 , however, the exclusion list is forcibly initialized when the access point is unable to be identified. Accordingly, the access point desired to be deleted from the connection targets may be identified, and therefore convenience to the user may be significantly impaired. 
     Accordingly, this embodiment attempts to assure that a predetermined access point is excluded from the connection targets. To be more detailed, in this embodiment the portable terminal possesses a reproduction of the exclusion list (hereinafter, “duplicate exclusion list”). In addition, when start of connection to an access point registered in the duplicate exclusion list (hereinafter, “excluded access point”) is detected, the portable terminal cuts off the connection to the excluded access point and temporarily deletes the corresponding network from the target list. The temporarily deleted network is re-registered in the target list at a predetermined time point. 
       FIG. 11  is a view illustrating an example of the schematic configuration of a portable terminal  2 - 3 . In this configuration, the first communication unit  21 , the second communication unit  22 , the operation unit  24 , the display unit  25 , the operating system  262 , the connection control unit  263 , and the timer unit  265  are the same as those depicted in  FIG. 9 , and therefore the description thereof will not be repeated. 
     The storage unit  23 - 3  stores therein, as one of the application programs, a setup initialization program or the like for initializing the settings related to the connection control, in addition to the programs stored in the storage unit  23 - 2  depicted in  FIG. 9 . The storage unit  23 - 3  also stores, as the data, an isolation list including the ESSID temporarily deleted from the target list, and the duplicate exclusion list which is the reproduction of the exclusion list. 
     The authentication unit  261 - 3  performs the web authentication with the gateway  5 . The authentication unit  261 - 3  registers the BSSID of the access point  3  in the exclusion list and the duplicate exclusion list. The authentication unit  261 - 3  also deletes the ESSID of the network from the target list and registers the ESSID in the isolation list. Further, the authentication unit  261 - 3  requests the wireless LAN connection control unit  264 - 2  to cut off the connection to the access point  3 . Details of such operations will be subsequently described. 
     The wireless LAN connection control unit  264 - 2  executes the wireless communication in compliance with IEEE 802.11 Standard. The wireless LAN connection control unit  264 - 2  registers the BSSID of the access point  3  in the exclusion list, and initializes the exclusion list. The wireless LAN connection control unit  264 - 2  also registers the ESSID of the network in the target list, and deletes the ESSID from the target list. The wireless LAN connection control unit  264 - 2  also notifies the connection status with respect to the access point  3 . Further, the wireless LAN connection control unit  264 - 2  cuts off the connection to the access point  3 . Still further, the wireless LAN connection control unit  264 - 2  performs scanning and notifies the result. Details of such operations will be subsequently described. 
     The setup initialization unit  266  initializes the settings related to the connection control. More specifically, the setup initialization unit  266  performs scanning at a predetermined time point, and initializes the exclusion list, the duplicate exclusion list, the target list, and the isolation list when the excluded access point  3  is not detected. Details of such operations will be subsequently described. 
     Hereinafter, the operation of the authentication unit  261 - 3  will be described. 
     When a predetermined access point  3  is detected, the authentication unit  261 - 3  requests the wireless LAN connection control unit  264 - 2  to register the BSSID of the access point  3  in the exclusion list. The authentication unit  261 - 3  also registers the BSSID in the duplicate exclusion list stored in the storage unit  23 - 3 . Further, the authentication unit  261 - 3  requests the wireless LAN connection control unit  264 - 2  to cut off the connection to the access point  3 . It will be assumed that the predetermined access point  3  is the one to which a connection requires a time exceeding a predetermined timeout period. 
     Upon receipt of a notice from the wireless LAN connection control unit  264 - 2  to the effect that connection to the access point  3  has been started, the authentication unit  261 - 3  looks up the duplicate exclusion list stored in the storage unit  23 - 3 , and determines whether the BSSID is registered. When the BSSID is registered, the authentication unit  261 - 3  requests the wireless LAN connection control unit  264 - 2  to delete the corresponding ESSID from the target list. The authentication unit  261 - 3  also registers the ESSID in the isolation list stored in the storage unit  23 - 3 . Further, the authentication unit  261 - 3  requests the wireless LAN connection control unit  264 - 2  to cut off the connection to the access point  3 . 
     Hereinafter, the operation of the wireless LAN connection control unit  264 - 2  will be described. 
     At a predetermined time point, the wireless LAN connection control unit  264 - 2  acquires an ESSID from the target list stored in the storage unit  23 - 3 , and broadcasts the probe request including the ESSID through the first communication unit  21 . Here, it will be assumed that the predetermined time point is the time that the connection to the access point  3  is cut off while the connection to the wireless LAN is ON. When the probe response is not received from the access point  3  through the first communication unit  21 , the wireless LAN connection control unit  264 - 2  acquires another ESSID from the target list stored in the storage unit  23 - 3 , and broadcasts the probe request including the ESSID through the first communication unit  21 . On the other hand, when the probe response is received from the access point  3  through the first communication unit  21 , the wireless LAN connection control unit  264 - 2  determines whether the BSSID included in the probe response is registered in the exclusion list stored in the storage unit  23 - 3 . When the BSSID is registered in the exclusion list, the wireless LAN connection control unit  264 - 2  acquires still another ESSID from the target list stored in the storage unit  23 - 3 , and broadcasts the probe request including the ESSID through the first communication unit  21 . When the access point  3  is not identified through the mentioned procedure, the wireless LAN connection control unit  264 - 2  repeats the same procedure after initializing the exclusion list. On the other hand, when the BSSID is not registered in the exclusion list, the wireless LAN connection control unit  264 - 2  stores the BSSID and the corresponding ESSID in the storage unit  23 - 3 . The wireless LAN connection control unit  264 - 2  transmits the authentication request to the access point  3  through the first communication unit  21 . The wireless LAN connection control unit  264 - 2  also notifies the authentication unit  261 - 3  that connection to the access point  3  has been started. 
     When the request for disconnection from the access point  3  is received from the authentication unit  261 - 3 , the wireless LAN connection control unit  264 - 2  cuts off the connection to the access point  3  which is in process or already completed. 
     Upon receipt of the request to register the BSSID in the exclusion list from the authentication unit  261 - 3 , the wireless LAN connection control unit  264 - 2  registers the BSSID in the exclusion list stored in the storage unit  23 - 3 . In addition, upon receipt of the request to initialize the exclusion list from the setup initialization unit  266 , the wireless LAN connection control unit  264 - 2  initializes the exclusion list (deletes the BSSID) stored in the storage unit  23 - 3 . 
     Upon receipt of the request to register the ESSID in the target list from the setup initialization unit  266 , the wireless LAN connection control unit  264 - 2  registers the ESSID in the target list stored in the storage unit  23 - 3 . In addition, upon receipt of the request to delete the ESSID from the target list from the authentication unit  261 - 3 , the wireless LAN connection control unit  264 - 2  deletes the ESSID from the target list stored in the storage unit  23 - 3 . 
     Upon receipt of the request for scanning from the setup initialization unit  266 , the wireless LAN connection control unit  264 - 2  broadcasts the probe request including the ESSID “ANY” through the first communication unit  21 . In addition, upon receipt of the probe response from the access point  3  through the first communication unit  21 , the wireless LAN connection control unit  264 - 2  extracts the BSSID from the probe response, and returns the BSSID to the setup initialization unit  266 . 
     Hereinafter, the operation of the setup initialization unit  266  will be described. 
     The setup initialization unit  266  requests, at a predetermined time point, the wireless LAN connection control unit  264 - 2  to perform the scanning, when at least one BSSID is registered in the duplicate exclusion list stored in the storage unit  23 - 3 . Here, it will be assumed that the predetermined time point is the time that the display unit  24  is turned ON while the connection to the wireless LAN is ON. 
     Upon receipt of the scanning result from the wireless LAN connection control unit  264 - 2 , the setup initialization unit  266  compares the scanning result with the duplicate exclusion list stored in the storage unit  23 - 3 , and determines whether the excluded access point  3  has been detected. When the excluded access point  3  is not detected, the setup initialization unit  266  again requests the wireless LAN connection control unit  264 - 2  to perform the scanning. 
     Upon receipt of the scanning result from the wireless LAN connection control unit  264 - 2 , the setup initialization unit  266  compares the scanning result with the duplicate exclusion list stored in the storage unit  23 - 3 , and determines whether the excluded access point  3  has been detected. When the excluded access point  3  is not detected this time either, the setup initialization unit  266  requests the wireless LAN connection control unit  264 - 2  to initialize the exclusion list. The setup initialization unit  266  also initializes the duplicate exclusion list (deletes the BSSID) stored in the storage unit  23 - 3 . Further, the setup initialization unit  266  acquires the ESSID from the isolation list stored in the storage unit  23 - 3 , and requests the wireless LAN connection control unit  264 - 2  to register the ESSID in the target list. The setup initialization unit  266  then initializes the isolation list (deletes the ESSID) stored in the storage unit  23 - 3 . 
       FIG. 12  is a view indicating an example of the operation sequence of the wireless communication system  1 . 
     When the predetermined access point  3  is detected (Yes at step S 1200 ), the authentication unit  261 - 3  requests the wireless LAN connection control unit  264 - 2  to register the ESSID of the access point  3  in the exclusion list (step S 1202 ). 
     The authentication unit  261 - 3  registers the BSSID also in the duplicate exclusion list stored in the storage unit  23 - 3  (step S 1204 ). 
     The authentication unit  261 - 3  requests the wireless LAN connection control unit  264 - 2  to cut off the connection to the access point  3  (step S 1206 ). 
     When the request for disconnection from access point  3  is received from the authentication unit  261 - 3 , the wireless LAN connection control unit  264 - 2  cuts off the connection to the access point  3 , which is in process or has been established (step S 1208 ). 
     At the predetermined time point, the wireless LAN connection control unit  264 - 2  acquires an ESSID from the target list stored in the storage unit  23 - 3 , and broadcasts the probe request including the ESSID through the first communication unit  21  (step S 1700 ). 
     The access point  3  returns the probe response when the ESSID in the received probe request is the same as its own ESSID or “ANY” (step S 1702 ). 
     When the probe response is not received from the access point  3  through the first communication unit  21 , the wireless LAN connection control unit  264 - 2  acquires another ESSID from the target list stored in the storage unit  23 - 3 , and broadcasts the probe request including the ESSID through the first communication unit  21  (step S 1700 ). 
     On the other hand, when the probe response is received from the access point  3  through the first communication unit  21 , the wireless LAN connection control unit  264 - 2  determines whether the BSSID included in the probe response is registered in the exclusion list stored in the storage unit  23 - 3 . When the BSSID is registered in the exclusion list, the wireless LAN connection control unit  264 - 2  acquires still another ESSID from the target list stored in the storage unit  23 - 3 , and broadcasts the probe request including the ESSID through the first communication unit  21  (step S 1700 ). 
     When the access point  3  is unable to be identified through the steps S 1700  to  1702 , the wireless LAN connection control unit  264 - 2  repeats the steps S 1700  to  1702  after initializing the exclusion list. 
     On the other hand, when the BSSID is not registered in the exclusion list, the wireless LAN connection control unit  264 - 2  stores the BSSID and the corresponding ESSID in the storage unit  23 - 3 . The wireless LAN connection control unit  264 - 2  also transmits the authentication request to the access point  3  through the first communication unit  21  (step S 1704 ). 
     The wireless LAN connection control unit  264 - 2  notifies the authentication unit  261 - 3  to the effect that connection to the access point  3  has been started (step S 1210 ) 
     Upon receipt of the notice from the wireless LAN connection control unit  264 - 2  to the effect that connection to the access point  3  has been started, the authentication unit  261 - 3  looks up the duplicate exclusion list stored in the storage unit  23 - 3 , and determines whether the BSSID is registered. When the BSSID is registered (Yes at step S 1212 ), the authentication unit  261 - 3  requests the wireless LAN connection control unit  264 - 2  to delete the corresponding ESSID from the target list (step S 1214 ). 
     The authentication unit  261 - 3  registers the ESSID in the isolation list stored in the storage unit  23 - 3  (step S 1216 ). 
     The authentication unit  261 - 3  requests the wireless LAN connection control unit  264 - 2  to cut off the connection to the access point  3  (step S 1218 ). 
     When the request for disconnection from the access point  3  is received from the authentication unit  261 - 3 , the wireless LAN connection control unit  264 - 2  cuts off the connection to the access point  3  which is in process (step S 1220 ). 
       FIG. 13  is a view indicating an example of another operation sequence of the wireless communication system  1 . 
     The setup initialization unit  266  requests, at the predetermined time point, the wireless LAN connection control unit  264 - 2  to perform the scanning, when at least one BSSID is registered in the duplicate exclusion list stored in the storage unit  23 - 3  (step S 1300 ). 
     Upon receipt of the request for scanning from the setup initialization unit  266 , the wireless LAN connection control unit  264 - 2  broadcasts the probe request including the ESSID “ANY” through the first communication unit  21  (step S 1302 ). 
     The access point  3  returns the probe response when the ESSID in the received probe request is the same as its own ESSID or “ANY” (step S 1304 ). 
     Upon receipt of the probe response from the access point  3  through the first communication unit  21 , the wireless LAN connection control unit  264 - 2  extracts the BSSID from the probe response, and returns the BSSID to the setup initialization unit  266  (step S 1306 ). 
     Upon receipt of the scanning result from the wireless LAN connection control unit  264 - 2 , the setup initialization unit  266  compares the scanning result with the duplicate exclusion list stored in the storage unit  23 - 3 , and determines whether the excluded access point  3  has been detected. When the excluded access point  3  is not detected (Yes at step S 1308 ), the setup initialization unit  266  again requests the wireless LAN connection control unit  264 - 2  to perform the scanning (step S 1310 ). 
     Upon receipt of the request for scanning from the setup initialization unit  266 , the wireless LAN connection control unit  264 - 2  broadcasts the probe request including the ESSID “ANY” through the first communication unit  21  (step S 1312 ). 
     The access point  3  returns the probe response when the ESSID in the received probe request is the same as its own ESSID or “ANY” (step S 1314 ). 
     Upon receipt of the probe response from the access point  3  through the first communication unit  21 , the wireless LAN connection control unit  264 - 2  extracts the BSSID from the probe response, and returns the BSSID to the setup initialization unit  266  (step S 1316 ). 
     Upon receipt of the scanning result from the wireless LAN connection control unit  264 - 2 , the setup initialization unit  266  compares the scanning result with the duplicate exclusion list stored in the storage unit  23 - 3 , and determines whether the excluded access point  3  has been detected. When the excluded access point  3  is not detected this time either (Yes at step S 1318 ), the setup initialization unit  266  requests the wireless LAN connection control unit  264 - 2  to initialize the exclusion list (step S 1320 ). 
     The setup initialization unit  266  also initializes the duplicate exclusion list stored in the storage unit  23 - 3  (step S 1322 ). 
     The setup initialization unit  266  acquires the ESSID from the isolation list stored in the storage unit  23 - 3 , and requests the wireless LAN connection control unit  264 - 2  to register the ESSID in the target list (step S 1324 ). 
     The setup initialization unit  266  initializes the isolation list stored in the storage unit  23 - 3  (step S 1326 ). 
     As described thus far, the predetermined access point can be surely excluded from the connection targets by having the reproduction of the exclusion list, and cutting off the connection to the access point and temporarily deleting the corresponding network from the target list upon detecting that the connection to the access point registered in the exclusion list has been started. 
     The present invention is not limited to this embodiment. For example, in this embodiment the access point  3  to which a connection requires a time exceeding the predetermined timeout period is registered in the exclusion list, however a different access point  3  may be registered. For example, the access point  3  that requires a time exceeding the predetermined timeout period for the authentication through the gateway  5  may be registered. Such an arrangement allows various types of access point  3  to be excluded from the connection targets. 
     In this embodiment, the scanning is performed at the time that the display unit  24  is turned ON while the connection to the wireless LAN is ON, however the scanning may be performed at a different time point. For example, the scanning may be performed when the authentication unit  261 - 3  is activated while the connection to the wireless LAN is ON, or in a period after the display unit  24  is turned ON until the display unit  24  is turned OFF while the portable terminal is connected to the access point  3 . Such an arrangement allows reduction of battery consumption. In addition, the time interval between the scanning sessions and the number of scanning times may be changed by the user or the system by modifying the setup file or the like. Such an arrangement allows the communication to be performed under various communication environments or the like. 
     Further, although the registration of the BSSID in the duplicate exclusion list and the registration of the ESSID in the isolation list are performed at different time points in this embodiment, the ESSID may be registered in the isolation list at the time that the BSSID is registered in the duplicate exclusion list. Likewise, although the initialization of the duplicate exclusion list and the initialization of the isolation list are performed at different time points in this embodiment, the duplicate exclusion list may be initialized at the time that the isolation list is initialized. With the mentioned arrangements, the disconnection from the excluded access point  3  as well as the initialization of the exclusion list and the target list can be more quickly performed. 
     Further, the exclusion list, the duplicate exclusion list, the target list, and the isolation list may be initialized, for example, when the connection to the wireless LAN is turned OFF, or when the number of excluded access points  3  registered exceeds an upper limit. The number of registered access points may be changed by the user or the system, by modifying the setup file or the like. With such arrangements, the storage unit  23 - 3  can be effectively utilized. 
     (Fifth Embodiment) 
     In the fourth embodiment, the scanning is performed at the predetermined time point, and the portable terminal re-registers the temporarily deleted network in the target list when the excluded access point is not detected. However, the excluded access point under a stealth setting is unable to be detected by the scanning, and hence the portable terminal may re-registers the temporarily deleted network in the target list despite the excluded access points being present in the network. In this embodiment, therefore, the portable terminal is restricted from performing the scanning in a predetermined period of time, when the predetermined network is temporarily deleted from the target list. 
       FIG. 14  is a view illustrating an example of the schematic configuration of a portable terminal  2 - 4 . In this configuration, the first communication unit  21 , the second communication unit  22 , the operation unit  24 , the display unit  25 , the operating system  262 , the connection control unit  263 , the wireless LAN connection control unit  264 - 2 , and the timer unit  265  are the same as those depicted in  FIG. 11 , and therefore the description thereof will not be repeated. 
     The storage unit  23 - 4  stores therein, as the data, a restriction target list including the ESSID of the network the scanning of which is to be restricted, and a restriction period of the scanning, in addition to the data stored in the storage unit  23 - 3  depicted in  FIG. 11 . 
     The authentication unit  261 - 4  performs the web authentication with the gateway  5 . The authentication unit  261 - 4  registers the BSSID of the access point  3  in the exclusion list and the duplicate exclusion list. The authentication unit  261 - 4  also deletes the ESSID of the network from the target list and registers the ESSID in the isolation list. Further, the authentication unit  261 - 3  requests the wireless LAN connection control unit  264 - 2  to cut off the connection to the access point  3 . Further, the authentication unit  261 - 4  sets the restriction period for each network. To be more specific, when the BSSID of the access point  3  is registered in the duplicate exclusion list stored in the storage unit  23 - 4 , the authentication unit  261 - 4  looks up the restriction target list stored in the storage unit  23 - 4  and determines whether the corresponding ESSID is registered. When the ESSID is registered, the authentication unit  261 - 4  acquires the restriction period from the storage unit  23 - 4 , and instructs the timer unit  265  to start clocking using the restriction period as argument. When the ESSID is not registered, the authentication unit  261 - 4  instructs the timer unit  265  to start clocking using the restriction period of “0” as argument. 
     The setup initialization unit  266 - 1  initializes the settings related to the connection control. The setup initialization unit  266 - 1  also restricts the wireless LAN connection control unit  264 - 2  from performing the scanning during the restriction period. To be more detailed, when at least one BSSID is registered in the duplicate exclusion list stored in the storage unit  23 - 4 , the setup initialization unit  266 - 1  instructs, at a predetermined time point, the timer unit  26  to make decision regarding the lapse of time. Upon receipt of a notice from the timer unit  265  to the effect that the restriction period has elapsed, the setup initialization unit  266 - 1  requests the wireless LAN connection control unit  264 - 2  to perform the scanning. 
       FIG. 15  is a view indicating an example of the operation sequence of the wireless communication system  1 . Out of the operation sequence, steps S 1200  to  1220 , and steps S 1700  to  1704  are the same as those included in  FIG. 12 , and therefore the description of those steps will not be repeated. 
     When the BSSID of the access point  3  is registered in the duplicate exclusion list stored in the storage unit  23 - 4 , the authentication unit  261 - 4  looks up the restriction target list stored in the storage unit  23 - 4  and determines whether the corresponding ESSID is registered. When the ESSID is registered, the authentication unit  261 - 4  acquires the restriction period from the storage unit  23 - 4 , and instructs the timer unit  265  to start clocking using the restriction period as argument (step S 1500 ). 
     When the ESSID is not registered, the authentication unit  261 - 4  instructs the timer unit  265  to start clocking using the restriction period of “0” as argument (step S 1500 ). 
       FIG. 16  is a view indicating an example of another operation sequence of the wireless communication system  1 . Out of the operation sequence, steps S 1302  to  1326  are the same as those included in  FIG. 13 , and therefore the description of those steps will not be repeated. 
     When at least one BSSID is registered in the duplicate exclusion list stored in the storage unit  23 - 4 , the setup initialization unit  266 - 1  instructs, at a predetermined time point, the timer unit  26  to make decision regarding the lapse of time. Upon receipt of the notice from the timer unit  265  to the effect that the restriction period has elapsed (Yes at step S 1600 ), the setup initialization unit  266 - 1  requests the wireless LAN connection control unit  264 - 2  to perform the scanning (step S 1300 ). 
     As described above, the predetermined access point under the stealth setting can also be surely excluded from the connection targets, by restricting the wireless LAN connection control unit  264 - 2  from performing the scanning during the predetermined period of time when the predetermined network is temporarily deleted from the target list. 
     The present invention is not limited to this embodiment. For example, in this embodiment the scanning is restricted during the restriction period when the predetermined network is temporarily deleted from the target list. Alternatively, the temporarily deleted network may be restricted from being re-registered in the target list during the restriction period, when no excluded access point  3  is detected by the scanning. In this case also, the predetermined access point under the stealth setting can be surely excluded from the connection targets. In addition, the restriction period may be changed for a different network, or may be changed by the user or the system, by modifying the setup file or the like. Such arrangements allow the communication to be performed under various communication environments or the like. 
     It should be understood that various changes, substitutions, and modifications can be made herein by those skilled in the art without departing from the scope and spirit of the present invention. 
     REFERENCE SIGNS LIST 
     
         
           1  Wireless communication system 
           2  portable terminal 
           21  First communication unit 
           22  Second communication unit 
           23  Storage unit 
           24  Operation unit 
           25  Display unit 
           26  Processing unit 
           261  Authentication unit 
           262  Operating system 
           263  Connection control unit 
           264  Wireless LAN connection control unit 
           3  Access point 
           4  Backbone network 
           5  Gateway 
           6  Authentication server 
           7  Internet 
           8  Server 
           9  Base station 
           10  Mobile phone network