Patent Publication Number: US-2015065128-A1

Title: Communication apparatus, computer product, and communication control method

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of International Application PCT/JP2012/061689, filed on May 7, 2012 and designating the U.S., the entire contents of which are incorporated herein by reference. 
    
    
     FIELD 
     The embodiments discussed herein are related a communication apparatus, a communication control program, and a communication control method. 
     BACKGROUND 
     A conventional communication apparatus has a communication function for connecting to a cellular telephone network and a communication function for connecting to a wireless local area network (LAN). The communication apparatus can connect to a network such as Internet by way of, for example, a base station of the cellular phone network or a base station of the wireless LAN, located at each site. 
     Related prior art includes, for example, a technique for detecting the position of a terminal based on the electric field strength of a signal received from the cellular network base station and detecting the position of a connection point to the wireless LAN based on the base station cell ID and the electric field strength of the received signal. For an example, refer to Japanese Laid-Open Patent Publication No. 2009-44659. 
     The conventional technology, however, gives rise to a problem of increased power consumption in the communication apparatus due to detection operations performed by the communication apparatus to detect a base station of the wireless LAN, etc. For example, in the case of starting the detection operations for detecting the wireless LAN base station when hand-over is performed, frequent hand-over brings about increases in the power consumption of the communication apparatus to detect the base station. 
     SUMMARY 
     According to an aspect of an embodiment, a communication apparatus includes a display unit configured to display an image; a processor configured to control the display; and a storage configured to store information processed by the processor. The processor, in each communication area of a base station that is communicable with the communication apparatus, upon connection to an access point enabling communication with the base station by a different communication method, correlates and stores to the storage as connection history information, a connection history of connection to the connected access point and the communication area, and when the display is caused to transition from a non-displaying state to a displaying state, scans the access point corresponding to the communication area, based on the connection history information. 
     The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is an explanatory view of an example of a communication control method according to a first embodiment; 
         FIG. 2  is an explanatory view of a system configuration example of a communication system  200 ; 
         FIG. 3  is a block diagram of an example of a hardware configuration of a communication apparatus  101 ; 
         FIG. 4  is an explanatory view (1) of an example of the contents of a connection table  400 ; 
         FIG. 5  is a block diagram of an example of a functional configuration of the communication apparatus  101  according to the first embodiment; 
         FIG. 6  is an explanatory view (1) of an operation example of the communication apparatus  101  according to the first embodiment; 
         FIG. 7  is an explanatory view (2) of an operation example of the communication apparatus  101  according to the first embodiment; 
         FIG. 8  is an explanatory view (3) of an operation example of the communication apparatus  101  according to the first embodiment; 
         FIG. 9  is an explanatory view (4) of an operation example of the communication apparatus  101  according to the first embodiment; 
         FIG. 10  is an explanatory view (5) of an operation example of the communication apparatus  101  according to the first embodiment; 
         FIG. 11  is a flowchart of an example of a determination process procedure of the communication apparatus  101  according to the first embodiment; 
         FIG. 12  is a flowchart of an example of a communication control process procedure of the communication apparatus  101  according to the first embodiment; 
         FIG. 13  is a flowchart of an example of an update process procedure of the communication apparatus  101  according to the first embodiment; 
         FIG. 14  is a block diagram of an example of a functional configuration of the communication apparatus  101  according to a second embodiment; 
         FIG. 15  is an explanatory view (1) of an operation example of the communication apparatus  101  according to the second embodiment; 
         FIG. 16  is an explanatory view (2) of an operation example of the communication apparatus  101  according to the second embodiment; 
         FIG. 17  is an explanatory view (3) of an operation example of the communication apparatus  101  according to the second embodiment; 
         FIG. 18  is an explanatory view (4) of an operation example of the communication apparatus  101  according to the second embodiment; 
         FIG. 19  is an explanatory view (5) of an operation example of the communication apparatus  101  according to the second embodiment; 
         FIG. 20  is an explanatory view (6) of an operation example of the communication apparatus  101  according to the second embodiment; 
         FIG. 21  is an explanatory view (7) of an operation example of the communication apparatus  101  according to the second embodiment; 
         FIG. 22  is a flowchart of an example of the determination process procedure of the communication apparatus  101  according to the second embodiment; 
         FIG. 23  is a flowchart of an example of a setting process procedure of the communication apparatus  101  according to the second embodiment; 
         FIGS. 24 and 25  are flowcharts of an example of the update process procedure of the communication apparatus  101  according to the second embodiment; 
         FIG. 26  is an explanatory view (2) of an example of the contents of the connection table  400 ; 
         FIG. 27  is a flowchart of an example of the update process procedure of the communication apparatus  101  according to a first updating method when connection to an access point APj is completed; 
         FIG. 28  is a flowchart of an example of a specific process procedure of the first update process; 
         FIGS. 29 and 30  are flowcharts of an example of the update process procedure of the communication apparatus  101  according to the first updating method when hand-over is detected; 
         FIG. 31  is an explanatory view (3) of an example of the contents of the connection table  400 ; 
         FIG. 32  is an explanatory view (4) of an example of the contents of the connection information  400 ; 
         FIG. 33  is a flowchart of an example of the update process procedure of the communication apparatus  101  according to a second updating method when connection to the access point APj is completed; 
         FIG. 34  is a flowchart of an example of the specific process procedure of the second update process; and 
         FIGS. 35 and 36  are flowcharts of an example of the update process procedure of the communication apparatus  101  according to the second updating method when hand-over is detected. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Embodiments of a communication apparatus, a communication control program, and a communication control method according to the present invention will be described with reference to the accompanying drawings. 
       FIG. 1  is an explanatory view of an example of a communication control method according to a first embodiment. In  FIG. 1 , a communication apparatus  101  is a computer capable of wireless communication with base stations  102  and  103 . The communication apparatus  101  has a screen  110  that displays various types of information. For example, the communication apparatus  101  is a smart phone, a cellular phone, a tablet-type personal computer (PC), a personal handy-phone system (PHS), etc. 
     The base stations  102  and  103  are wireless stations that can communicate wirelessly with a communication apparatus  101  in each communication area and that act as base stations for allowing the communication apparatus  101  to connect to the network. For example, the base stations  102  and  103  are base stations of a mobile communication network (cellular phone network) or access points of a wireless local area network (LAN), interspersed throughout the areas. 
     The communication apparatus  101  detects the base stations  102  and  103  by respectively different detection operations to enable connection to the network via the detected base station  102  or  103 . The network is for example the mobile communication network, the LAN, a wide area network (WAN), the Internet, etc. 
     As used herein, the “detection operation” refers to a so-called scanning operation for searching for a communicable base station  102  or  103  among the base stations  102  and  103  interspersed throughout the areas. The detection operations for detecting the base stations  102  and  103  differ depending on for example, differences in communication method, communication standards, communication performance, communication service, etc. of the wireless communication. 
     To detect the base station  103 , the communication apparatus  101  performs a detection operation different from the detection operation for detecting the base station  102 . For this reason, the communication apparatus  101  consumes power through the detection operation for detecting the base station  102  and consumes power through the detection operation for detecting the base station  103 . 
     In the following description, a base station of the mobile communication network is used as an example of the base station  102  while an access point of the wireless LAN is used as an example of the base station  103 . A communication area of the base station  102  is referred to as a “cell” and the base station  103  is referred to as an “access point  103 ”. 
     In the example of  FIG. 1 , base stations  102 - 1  to  102 - 3  are depicted as the base station  102  of the mobile communication network and access points  103 - 1  to  103 - 10  are depicted as the access points  103  of the wireless LAN. Cells C1 to C3 of the base stations  102 - 1  to  102 - 3  are also depicted together with communication areas A1 to A10 of the access points  103 - 1  to  103 - 10 . 
     For example, the access points  103  of the wireless LAN tends to have a faster maximum communication speed with a higher transmission efficiency but have a narrower communication area than those of the base stations  102  of the mobile communication network. Use of the access points  103  of the wireless LAN is often limited to only users subscribing a specific service. 
     In a case where no available access point  103  exists around the communication apparatus  101 , it is not desirable for the communication apparatus  101  to perform the detection operation for the access point  103 . When using the access point  103 , the user may specify the start of the detection operation for the access point  103 . In this case, the user is required to perform an input operation and may not know the position of an available access point  103 . 
     Thus, in the first embodiment, a communication apparatus  101  determines the presence or absence of a connection history indicating connection to a wireless LAN access point  103  of a base station  102  of a mobile communication network in which the communication apparatus is located, based on a transition from a non-display state to a display state of the screen  110 . The communication apparatus  101  starts the detection operation for the access point  103  if a connection history for the access point  103  is present. 
     As a result, the communication apparatus  101  prevents the impairment of the usability and suppresses the power consumption required for the detection operation for the access point  103 . The communication apparatus  101  is assumed to periodically perform the detection operation for detecting the base station  102  of the mobile communication network. An example of the communication control process of the communication apparatus  101  according to the first embodiment will hereinafter be described. 
     (1) The communication apparatus  101  detects a transition from a non-display state to a display state of the screen  110 . The display state of non-display (screen off) refers to, for example, a state where power supply to the screen  110  is suspended. The display state of display (screen on) refers to, for example, a state where power supply to the screen  110  is being performed. 
     For example, the communication apparatus  101  receives a user input operation for switching the display state of the screen  110  from the non-display state to the display state, to thereby detect a transition from a non-display state to a display state of the screen  110 . In the example of  FIG. 1 , a transition from a non-display state to a display state of the screen  110  is detected at a point P1 where the home of the user of the communication apparatus  101  is located. 
     (2) Upon detecting a transition from a non-display state to a display state of the screen  110 , the communication apparatus  101  determines based on connection history information whether a connection history is present for an access point  103  in a cell of the base station  102  in which the communication apparatus is located. 
     As used herein, the connection history information is information for specifying, among a cell group (e.g., cells C1 to C3), a cell in which a connection operation to the access point  103  is performed. The connection operation to the access point  103  is an operation for connecting via the access point  103  to a network such as Internet. 
     A connection history for the access point  103  is a history indicating that a connection process of connecting to the access point  103  has been normally completed by the communication apparatus  101 . The connection process of connecting to the access point  103  includes for example a user authentication process of the communication apparatus  101 . A cell having a connection history for the access point  103  is a cell having a higher possibility of having a user available access point  103  therein, as compared with a cell having no connection history for the access point  103 . 
     In  FIG. 1 , a bold-circled communication area of the access point  103  designates a communication area of the access point  103 , having a connection history of the communication apparatus  101 . 
     For example, at a point P1, the communication apparatus  101  communicates with the base station  102 - 1  of the mobile communication network to thereby specify the cell C1 of the base station  102 - 1  in which the communication apparatus is located. The communication apparatus  101  then refers to the connection history information to determine whether a connection history for the access point  103  in the specified cell C1 exists. 
     The example of  FIG. 1  depicts the access points  103 - 1  and  103 - 4  having a history of connection in the cell C1 of the base station  102 - 1 . Therefore, the communication apparatus  101  determines that a connection history for the access point  103  in the cell C1 of the base station  102 - 1  in which the communication apparatus is located exists. 
     (3) The communication apparatus  101  controls the detection operation for the access point  103  based on the obtained determination result. For example, if the communication apparatus  101  determines that a connection history for the access point  103  exists, the communication apparatus  101  starts the detection operation for the access point  103 . On the other hand, if the communication apparatus  101  determines that no connection history for the access point  103  exists, the communication apparatus  101  does not start the detection operation for the access point  103 . 
     In the example of  FIG. 1 , a connection history for the access point  103  in the cell C1 exists and therefore, the communication apparatus  101  starts the detection operation for the access point  103 . As a result, the access point  103 - 1  for example is detected and the communication apparatus  101  can connect to a network such as the Internet by way of the access point  103 - 1 . 
     (4) The communication apparatus  101  detects a transition from a display state to a non-display state of the screen  110 . For example, the communication apparatus  101  receives a user input operation for switching the display state of the screen  110  from the display state to the non-display state and thereby, detects a transition from the display state to the non-display state of the screen  110 . 
     In the example of  FIG. 1 , a transition from a display state to a non-display state of the screen  110  is detected at a point P2 en route from the point P1 where the home of the user is located to a point P3 where a convenience store is located. 
     (5) Upon detecting a transition from a display state to a non-display state of the screen  110 , the communication apparatus  101  stops the detection operation for the access point  103 . Thus, the detection operation for the access point  103  is suspended in response to a transition from the display state to the non-display state of the screen  110  so that the power consumption of the communication apparatus  101  can be suppressed. 
     In this manner, the communication apparatus  101  controls the detection operation for the access point  103  based on a transition of the display state of the screen  110 . 
     For example, suppose that a transition from a non-display state to a display state of the screen  110  is detected at a point P4 en route from the point P3 where the convenience store is located to a point P5 where a nearest station is located. In this case, the communication apparatus  101  determines whether a connection history for an access point  103  is present in the cell C2 of the base station  102 - 2  in which the communication apparatus is located. 
     In the example of  FIG. 1 , in the cell 2, due to the absence of an access point  103  having a connection history, the communication apparatus  101  determines that connection history for an access point  103  is not present in the cell C2. In this case, the communication apparatus  101  does not start the detection operation for the access point  103  in the cell C2. 
     For example, suppose that a transition from a non-display state to a display state of the screen  110  is detected at a point P6 en route from the point P5 where the nearest station is located to a point P7 where a company is located. In this case, the communication apparatus  101  determines whether a connection history for an access point  103  is present in the cell C3 of the base station  102 - 3  in which the communication apparatus is located. 
     In the example of  FIG. 1 , due to the presence of the access point  103 - 7  having a connection history in the cell 3, the communication apparatus  101  determines that for the cell C3, connection history for an access point  103  is present. Hence, the communication apparatus  101  starts the detection operation for the access point  103  in the cell C3. 
     According to the communication apparatus  101  described above, when the screen  110  transitions from a non-display state to a display state, the communication apparatus  101  can determine whether a connection history for the access point  103  in the cell of the base station  102  in which the communication apparatus  101  is located exists. In the case of the presence of the connection history for the access point  103 , the communication apparatus  101  can start the detection operation for the access point  103 . 
     Thus, based on a transition from a non-display state to a display state of the screen  110 , an available access point  103  can be detected in a cell having a connection history for the access point  103  without the need for a user input operation, thereby preventing drops in usability. 
     According to the communication apparatus  101 , when no connection history for the access point  103  is present for the cell of the base station  102  and in which the communication apparatus is located, the communication apparatus  101  does not start the detection operation for the access point  103 . This suppresses the detection operation for the access point  103  in a cell where no available access point is located and achieves a reduction in the power consumption of the communication apparatus  101  as well as a reduction in the traffic between the communication apparatus  101  and the access point  103 . 
     A system configuration example of a communication system  200  according to the first embodiment will be described. 
       FIG. 2  is an explanatory view of a system configuration example of the communication system  200 . In  FIG. 2 , the communication system  200  includes the communication apparatus  101 , base stations BS1 to BSn, access points AP1 to APm, and a server  201 . In the communication system  200 , the base stations BS1 to BSn, the access points AP1 to APm, and the server  201  are connected together by way of a network  210 . The network  210  includes, for example, the mobile communication network, LAN, WAN, Internet, etc. 
     The base stations BS1 to BSn are base stations of the mobile communication network, interspersed throughout the areas. In the following description, any arbitrary base station among the base stations BS1 to BSn may be referred to as “base station BSi” and the communication area indicative of a communicable range of the base station BSi may be referred to as “cell Ci” (i=1, 2, . . . , n). The base station  102  depicted in  FIG. 1  corresponds to the base station BSi. 
     The access points AP1 to APm are base stations of the wireless LAN, interspersed throughout the areas. The access points AP1 to APm may include mobile access points or access points equipped on a mobile vehicle such as a train and a bus. In the following description, any arbitrary access point among the access points AP1 to APm may be referred to as “access point APj” and the communication area indicative of a communicable range of the access point APj may be referred to as “communication area Aj” (j=1, 2, . . . , m). The access point  103  depicted in  FIG. 1  corresponds to the access point APj. 
     The communication apparatus  101  can wirelessly communicate with the base station BSi in the cell Ci and can connect to the network  210  via the base station BSi. The communication apparatus  101  can wirelessly communicate with the access point APj in the communication area Aj and can connect to the network  210  via the access point APj. 
     The server  201  is a computer that provides a service to the communication apparatus  101 . The service is information processing provided to the communication apparatus  101 , such as an email service, a telephone service, and a web service. For example, the server  201  includes an email server, a web server, an application server, and a database server. 
     Although a single communication apparatus  101  and a single server  201  are depicted in  FIG. 2 , configuration is not limited hereto. For example, the communication apparatus  101  may be disposed for each of the users utilizing the communication system  200 , and the server  201  may be disposed for each of service providers. 
       FIG. 3  is a block diagram of an example of a hardware configuration of the communication apparatus  101 . As depicted in  FIG. 3 , the communication apparatus includes a CPU  301 , memory  302 , a display  303 , a keypad  304 , a public network interface (I/F)  305 , a wireless LAN (WLAN) I/F  306 , audio signal processing unit  307 , a speaker  308 , and a microphone  309 , respectively connected to a bus  300 . 
     The CPU  301  governs overall control of the communication apparatus  101 . The memory  302 , for example, includes read-only memory (ROM), random access memory (RAM), flash ROM, etc. For example, the flash ROM stores an operating system (OS) program; the ROM stores application programs; and the RAM is used as a work area of the CPU  301 . Programs stored by the memory  302  are loaded onto the CPU  301  and the encoded processing is executed by the CPU  301 . 
     The display  303  displays, for example, data such as text, images, functional information, etc., in addition to a cursor, icons, and/or tool boxes. A liquid crystal display, an organic electroluminescence (EL) display, and the like may be employed as the display  107 . The screen  110  depicted in  FIG. 1  corresponds to the display  303 . 
     The keypad  304  includes, for example, keys for inputting letters, numerals, and various instructions and performs the input of data. Alternatively, a touch-panel-type input pad or numeric keypad, etc. may be adopted. 
     The public network I/F  305  is connected to the network  210  via the base station BSi of the mobile communication network, and is connected to other computers (e.g., the server  201 ) via the network  210 . The public network I/F  305  administers an internal interface with the network  210  and controls the input and output of data with respect to other computers. 
     The WLAN I/F  306  is connected to the network  210  via an access point APj of a wireless LAN, and is connected to other computer via the network  210 . The WLAN I/F  306  administers an internal interface with the network  210  and controls the input and output of data with respect to other computers. 
     The audio signal processing unit  307  is connected to the speaker  308  and the microphone  309 . For example, sound received by the microphone  309  is A/D converted by the audio signal processing unit  307 ; and from the speaker, the sound is output. 
     Although not depicted, in addition to the components above, the communication apparatus  101  further includes, for example, a memory controller that controls the reading and writing of data with respect to the memory  302 , a power management unit (PMU) that supplies source voltage to the components; a battery; various timers; a global positioning system (GPS) unit; etc. Hardware of the base station BSi and of the access point APi includes, for example, a CPU, memory, an I/F, auxiliary memory apparatuses, a bus, etc. 
     A connection table  400  used by the communication apparatus  101  will be described. The connection table  400  is implemented by the memory  302  depicted in  FIG. 3 , for example. 
       FIG. 4  is an explanatory view (1) of an example of the contents of the connection table  400 . In  FIG. 4 , the connection table  400  has fields for cell IDs, SSIDs, and last connection times. By entering information into the fields, the connection information is stored as records (e.g., connection records  400 - 1  to  400 - 4 ). 
     A cell ID is identification information for identifying the base station BSi of the mobile communication network. A service set identifier (SSID) is identification information for identifying the access point APj of the wireless LAN. For example, an extended SSID (ESSID) or a basic SSID (BSSID) can be used as the SSID. The last connection time indicates the date and time when the last connection to the access point APj was made. 
     In the case of the connection record  400 - 1 , for example, the cell ID “C1”, the SSID “AP2”, and the last connection time “2011,03.03.12.23” are shown associated with one another. The connection record  400 - 1  enables identification of the date and time “March 3, 2011 at 12:23” when the communication apparatus  101  last connected to the access point AP2 in the cell C1 of the base station BS1. The connection history information described in  FIG. 1  corresponds to the connection information in the connection table  400 . 
       FIG. 5  is a block diagram of an example of a functional configuration of the communication apparatus  101  according to the first embodiment. In  FIG. 5 , the communication apparatus  101  is configured to include a detecting unit  501 , an acquiring unit  502 , a first communicating unit  503 , a determining unit  504 , a communication control unit  505 , a second communicating unit  506 , and an updating unit  507 . The detecting unit  501  to the updating unit  507  function as a control unit and are implemented by for example, causing a CPU  301  to execute a program stored in the memory  302  of  FIG. 3  or by use of hardware such as the public network I/F  305  and the WLAN I/F  306 . The processing results of the function units are stored in the memory  302  for example. 
     The detecting unit  501  has a function to detect a transition from a non-display state to a display state of the display  303  (see  FIG. 3 ). For example, when the state of the display  303  is switched from the non-display state to the display state through a user input operation via the keypad  304 , the detecting unit  501  detects a transition from the non-display state to the display state of the display  303 . 
     For example, when a resume function resumes the operation from the state immediately before a transition to the non-display state of the display  303 , the detecting unit  501  may detect the transition from the non-display state to the display state of the display  303 . For example, when an application such as an alarm activated at a certain time goes on, the detecting unit  501  may detect the transition from the non-display state to the display state of the display  303 . 
     The detecting unit  501  has a function of detecting a transition from the display state to the non-display state of the display  303 . For example, when the state of the display  303  is switched from the display state to the non-display state through a user input operation via the keypad  304 , the detecting unit  501  detects a transition from the display state to the non-display state of the display  303 . 
     For example, when a screen off timer reaches a predetermined value, the detecting unit  501  may detect the transition from the display state to the non-display state of the display  303 . The screen off timer is a timer for measuring the time of the transition from the display state to the non-display state of the display  303 . For example, in the case of a transition to a power-saving mode to control the power supply to the display  303 , the detecting unit may detect the transition from the display state to the non-display state of the display  303 . 
     The acquiring unit  502  has a function of acquiring a cell ID for identifying a cell Ci in which the communication apparatus is located, among the cells C1 to Cn of the base stations BS1 to BSn. For example, the acquiring unit  502  acquires, as the cell ID of the cell Ci in which the communication apparatus is located, a cell ID included in base station information received by the first communicating unit  503  communicating with the base station BSi. The first communicating unit  503  receives periodically (e.g., every 2.56 seconds) the base station information including the cell ID of the cell Ci, from a communicable base station BSi among the base stations BS1 to BSn. 
     The base stations BS1 to BSn may include plural base stations with which the communication apparatus  101  is communicable. In this case, for example, the acquiring unit  502  may acquire, as the cell ID for identifying a cell Ci in which the communication apparatus is located, a cell ID included in the base station information of a base station whose signal strength is greatest among the communicable base stations. 
     The determining unit  504  has a function of determining whether a connection record is present for an access point APj in the cell Ci in which the communication apparatus is located, when the detecting unit  501  detects a transition of the display state from the non-display state to the display state. As used herein, the connection record for an access point APj is a connection history indicative of the completion of a connection operation with respect to the access point APj. A connection operation with respect to the access point APj is an operation of the communication apparatus  101  for connecting to the network  210  by way of the access point APj. 
     For example, first, the determining unit  504  refers to the connection table  400  depicted in  FIG. 4 , to determine whether an SSID of the access point APj is stored corresponding to the cell ID acquired by the acquiring unit  502 . If the SSID of the access point APj is present, the determining unit  504  determines that the connection record is present for the access point APj in the cell Ci in which the communication apparatus is located. On the other hand, if no SSID of the access point APj is present, the determining unit  504  determines that no connection record is present for the access point APj in the cell Ci in which the communication apparatus  101  is located. 
     The communication control unit  505  has a function of controlling the detection operation for the access point APj based on the determination result obtained by the determining unit  504 . For example, if it is determined that a connection record is present for the access point APj in the cell Ci in which the communication apparatus is located, the communication control unit  505  controls the second communicating unit  506  communicating with the access point APj, to start a detection operation for the access point APj. On the other hand, if it is determined that no connection record is present for the access point APj in the cell Ci in which the communication apparatus is located, the communication control unit  505  does not start the detection operation for the access point APj. 
     Describing in more detail, if it is determined that a connection record is present for the access point APj in the cell Ci in which the communication apparatus is located, the communication control unit  505  sets a detection operation flag to ON. The detection operation flag is a flag indicative of whether the detection operation for the access point APj is to be performed periodically. The detection operation flag is stored in, for example, a register of the memory  302  or the CPU  301 . 
     If the detection operation flag is ON, the communication control unit  505  controls the second communicating unit  506  to cyclically perform the detection operation for the access point APj. The cycle of the detection operation for the access point APj can be set arbitrarily. For example, a timer controls the start timing when the detection operation for the access point APj is performed periodically. 
     An example of the detection operation for the access point APj will be described. For example, the communication control unit  505  controls the second communicating unit  506  to send a probe request signal to channels (CHs) used in the wireless LAN. As a result, the communication control unit  505  receives a probe response signal that includes the SSID so that a communicable access point APj can be detected. 
     The communication control unit  505  has a function of controlling the second communicating unit  506  to start the connection operation for the detected access point APj. For example, if a connection record for the detected access point APj is present, the communication control unit  505  controls the second communicating unit  506  to start the connection operation for the access point APj. 
     On the other hand, if a connection record for the detected access point APj is not present, the communication control unit  505  does not start the connection operation for the access point APj. The connection record for the detected access point APj is stored for example in the memory  302  corresponding to the SSID of the access point APj. 
     The communication control unit  505  may control the second communicating unit  506  through a user input operation to start the connection operation for the detected access point APj. For example, at the time of the first connection to the access point APj, the communication control unit  505  controls the second communicating unit  506  through a user input operation to start the connection operation for the detected access point APj. 
     The updating unit  507  has a function of updating the connection time to the access point APj when the connection to the access point APj is completed. As used herein, the connection time refers to, for example, the last time of a connection to the access point APj. 
     For example, first, the updating unit  507  retrieves from the connection table  400  depicted in  FIG. 4 , connection information corresponding to the cell ID of the cell Ci in which the communication apparatus is located. The updating unit  507  overwrites the SSID of the detected access point APj into the SSID field of the retrieved connection information. The updating unit  507  overwrites the connection time to the detected access point APj into the last connection time field of the retrieved connection information. 
     If a connection record is not present for the access point APj in the cell Ci in which the communication apparatus is located, connection information is not retrieved that corresponds to the cell ID of the cell Ci in which the communication apparatus is located. In this case, the updating unit  507  enters into the fields of the connection table  400 , the cell ID of the cell Ci in which the communication apparatus is located, the SSID of the detected access point APj, and the connection time. As a result, new connection information is newly entered as a record in the connection table  400 . 
     In the case of entering new connection information in the connection table  400 , the updating unit  507  may calculate the total number M of connection records stored in the connection table  400 . Then, if the calculated total number M reaches or exceeds a threshold value M max , the updating unit  507  may delete the connection record whose last connection time is oldest, among the connection records stored in the connection table  400 . 
     The threshold value M max  represents an upper limit for the number of the connection records that can be entered in the connection table  400 . The threshold value M max  can be set arbitrarily and, for example, is stored in the previously installed memory  302 . Thus, by setting the upper limit value for the total number M of connection records that can be entered in the connection table  400 , the number of records in the connection table  400  can be prevented from increasing over the upper limit value. 
     When the detecting unit  501  detects a transition from the display state to the non-display state of the display  303 , the communication control unit  505  may stop the detection operation for the access point APj. For example, in the case of a transition to the non-display state of the display  303 , the communication control unit  505  may not perform the detection operation for the access point APj even though the detection operation flag is ON or the detection operation flag may be set to OFF. This suppresses the detection operation for the access point APj when the state of the display  303  is the non-display state and thereby suppresses the power consumption of the communication apparatus  101 . 
     If it is determined by the determining unit  504  as a result of the start of the detection operation for the access point APj, that a connection record for the access point APj is not present, the communication control unit  505  may stop the detection operation for the access point APj. For example, if a connection record is not present for the access point APj in the cell Ci in which the communication apparatus is located, the communication control unit  505  sets the detection operation flag to OFF. This can bring the cyclically performed detection operation for the access point APj to an end. 
     With reference to  FIGS. 6 to 10 , an operation example of the communication apparatus  101  according to the first embodiment will be described. 
       FIG. 6  is an explanatory view (1) of an operation example of the communication apparatus  101  according to the first embodiment. The operation example of the communication apparatus  101  depicted in  FIG. 6  is an example of operation performed when the detection operation flag is set to ON in response to a transition from the non-display state to the display state of the display  303 . 
     (6-1) The detecting unit  501  detects a transition from the non-display state to the display state of the display  303 . In the example of  FIG. 6 , the transition from the non-display state to the display state of the display  303  is detected as a result of switching from the non-display state to the display state of the display  303  through a user input operation. 
     (6-2) The determining unit  504  requests the acquiring unit  502  to acquire a cell ID of the cell Ci in which the communication apparatus is located and thereby, acquires the cell ID of the cell Ci in which the communication apparatus is located. In the example of  FIG. 6 , “C1” is acquired as the cell ID of the cell Ci in which the communication apparatus is located. 
     (6-3) The determining unit  504  refers to the connection table  400  to determine whether a connection record is present for the access point APj in the cell Ci in which the communication apparatus is located. In the example of  FIG. 6 , connection record  400 - 1  corresponding to the acquired cell ID “C1” is already entered and hence, it is determined that a connection record for the access point APj is present. 
     (6-4) The determining unit  504  sends to the communication control unit  505 , an ON setting request for the detection operation flag. At this time, if a read-out detection operation flag is OFF, the determining unit  504  may send the ON setting request for the detection operation flag to the communication control unit  505 . This can stop the ON setting request sending when the detection operation flag is ON, alleviating the processing load of the communication apparatus  101 . 
     (6-5) Upon receiving an ON setting request for the detection operation flag, the communication control unit  505  returns an Ack to the determining unit  504  and if the detection operation flag is OFF, sets the detection operation flag to ON. As a result, the communication control unit  505  controls the communicating units to cyclically perform the detection operation for the access point APj. 
     In this manner, according to the communication apparatus  101 , when the state of the display  303  transitions from the non-display state to the display state, the detection operation for the access point APj can be started if a connection record is present for the access point APj in the cell Ci in which the communication apparatus  101  is located. 
       FIG. 7  is an explanatory view (2) of an operation example of the communication apparatus  101  according to the first embodiment. The operation example of the communication apparatus  101  depicted in  FIG. 7  is an example of operation when the detection operation flag is set to OFF in response to a transition from the non-display state to the display state of the display  303 . 
     (7-1) The detecting unit  501  detects a transition from the display state to the non-display state of the display  303 . In the example of  FIG. 7 , the transition from the non-display state to the display state of the display  303  is detected as a result of switching from the non-display state to the display state of the display  303  through a user input operation. 
     (7-2) The determining unit  504  requests the acquiring unit  502  to acquire a cell ID of the cell Ci in which the communication apparatus is located and thereby, acquires the cell ID of the cell Ci in which the communication apparatus is located. In the example of  FIG. 7 , “C2” is acquired as the cell ID of the cell Ci in which the communication apparatus is located. 
     (7-3) The determining unit  504  refers to the connection table  400  to determine whether a connection record is present for the access point APj in the cell Ci in which the communication apparatus is located. In the example of  FIG. 7 , connection information corresponding to the acquired cell ID “C2” is not entered and hence, it is determined that no connection record for the access point APj is present. 
     (7-4) The determining unit  504  sends to the communication control unit  505 , an OFF setting request for the detection operation flag. At this time, when a read-out detection operation flag is ON, the determining unit  504  may send the OFF setting request for the detection operation flag to the communication control unit  505 . This can stop the OFF setting request sending when the detection operation flag is OFF, alleviating the processing load of the communication apparatus  101 . 
     (7-5) Upon receiving an OFF setting request for the detection operation flag, the communication control unit  505  returns an Ack to the determining unit  504  and if the detection operation flag is ON, sets the detection operation flag to OFF. As a result, the communication control unit  505  terminates the detection operation for the access point APj. 
     In this manner, according to the communication apparatus  101 , when the state of the display  303  transitions from the non-display state to the display state, the detection operation for the access point APj can be terminated if no connection record is present for the access point APj in the cell Ci in which the communication apparatus  101  is located. 
       FIG. 8  is an explanatory view (3) of an operation example of the communication apparatus  101  according to the first embodiment. The operation example of the communication apparatus  101  depicted in  FIG. 8  is an example of operation performed when connection to the access point APj is completed. 
     (8-1) Upon receiving from the communication control unit  505 , completion notification concerning connection to the access point APj, the updating unit  507  reads out connection information from the connection table  400 . 
     (8-2) The updating unit  507  requests the acquiring unit  502  to acquire the cell ID of the cell Ci in which the communication apparatus is located and thereby, acquires the cell ID of the cell Ci in which the communication apparatus is located. In the example of  FIG. 8 , “C1” is acquired as the cell ID of the cell Ci in which the communication apparatus is located. 
     (8-3) The updating unit  507  requests the communication control unit  505  to acquire the SSID of the access point APj to which connection has been completed and thereby, acquires the SSID of the access point APj currently connected. In the example of  FIG. 8 , “AP2” is acquired as the SSID of the access point APj currently connected. 
     (8-4) The updating unit  507  updates the contents of the connection table  400 . For example, first, the updating unit  507  retrieves from among read-out connection records, connection records corresponding to the cell ID of the cell Ci in which the communication apparatus  101  is located. The updating unit  507  then determines whether the SSID of the access point APj currently connected is among the retrieved connection records. 
     In the example of  FIG. 8 , the connection record  400 - 1  is retrieved that corresponds to the cell ID “C1” of the cell C1 in which the communication apparatus  101  is located. The SSID “AP2” of the access point AP2 currently connected is in the retrieved connection record  400 - 1 . In this case, the updating unit  507  overwrites “2011.03.04.08.50”, i.e., the connection time of connection to the access point AP2 into the last connection time field of the connection record  400 - 1 . 
     The connection time of connection to the access point AP2 may be for example the reception time when completion notification concerning connection to the access point APj is received or may be included in the completion notification concerning the connection to the access point APj. The reception time is measured, for example, by a measuring function of the communication apparatus  101 . 
     In this manner, according to the communication apparatus  101 , when connection to the access point APj is completed, the connection information in the connection table  400  and corresponding to the cell ID of the cell Ci in which the communication apparatus  101  is located can be updated. 
       FIG. 9  is an explanatory view (4) of an operation example of the communication apparatus  101  according to the first embodiment. The operation example of the communication apparatus  101  depicted in  FIG. 9  is an example of operation performed when connection to the access point APj is completed. 
     (9-1) Upon receiving from the communication control unit  505 , completion notification concerning the connection to the access point APj, the updating unit  507  reads out connection information from the connection table  400 . 
     (9-2) The updating unit  507  requests the acquiring unit  502  to acquire the cell ID of the cell Ci in which the communication apparatus is located and thereby, acquires the cell ID of the cell Ci in which the communication apparatus is located. In the example of  FIG. 9 , “C1” is acquired as the cell ID of the cell Ci in which the communication apparatus is located. 
     (9-3) The updating unit  507  requests the communication control unit  505  to acquire the SSID of the access point APj to which connection has been completed and thereby, acquires the SSID of the access point APj currently connected. In the example of  FIG. 9 , “AP3” is acquired as the SSID of the access point APj currently connected. 
     (9-4) The updating unit  507  updates the contents of the connection table  400 . For example, first, the updating unit  507  retrieves from read-out connection information, connection information corresponding to the cell ID of the cell Ci in which the communication apparatus  101  is located. The updating unit  507  then determines whether the SSID of the access point APj currently connected is in the retrieved connection information. 
     In the example of  FIG. 9 , the connection record  400 - 1 , which corresponds to the cell ID “C1” of the cell C1 in which the communication apparatus  101  is located, is retrieved. The SSID “AP3” of the access point AP3 currently connected is not in the retrieved connection record  400 - 1 . In this case, the updating unit  507  overwrites the SSID “AP3” of the access point AP3 currently connected, into the SSID field of the connection record  400 - 1 . Furthermore, the updating unit  507  overwrites “2011.03.03.09.00”, i.e., the connection time of connection to the access point AP3, into the last connection time field of the connection record  400 - 1 . 
     In this manner, according to the communication apparatus  101 , when the connection to the access point APj is completed, the connection information that corresponds to the cell ID of the cell Ci in which the communication apparatus  101  is located can be updated in the connection table  400 . 
       FIG. 10  is an explanatory view (5) of an operation example of the communication apparatus  101  according to the first embodiment. The operation example of the communication apparatus  101  depicted in  FIG. 10  is an example of operation performed when operation for connection to the access point APj is started. 
     (10-1) As a result of starting operation for connection to the access point APj through a user input operation, the updating unit  507  receives from the communication control unit  505 , completion notification concerning the connection to the access point APj. 
     (10-2) The updating unit  507  requests the acquiring unit  502  to acquire the cell ID of the cell Ci in which the communication apparatus is located and thereby, acquires the cell ID of the cell Ci in which the communication apparatus is located. In the example of  FIG. 10 , “C1” is acquired as the cell ID of the cell Ci in which the communication apparatus is located. 
     (10-3) The updating unit  507  requests the communication control unit  505  to acquire the SSID of the access point APj to which connection has been completed and thereby, acquires the SSID of the access point APj currently connected. In the example of  FIG. 10 , “AP2” is acquired as the SSID of the access point APj currently connected. 
     (10-4) The updating unit  507  reads out connection information from the connection table  400 . The order of processes (10-2) to (10-4) is arbitrary. 
     The updating unit  507  updates the contents of the connection table  400 . For example, first, the updating unit  507  retrieves from read-out connection information, connection information corresponding to the cell ID of the cell Ci in which the communication apparatus  101  is located. A case is assumed where connection to the access point APj is made in the cell C1 in which the communication apparatus  101  is located. 
     Further, connection information that corresponds to the cell ID of the cell Ci in which the communication apparatus is located is not retrieved. In this case, the updating unit  507  enters into the fields in the connection table  400 , the cell ID of the cell Ci in which the communication apparatus is located, the SSID of the access point APj currently connected, and the connection time. 
     As a result, new connection information is entered as a record in the connection table  400 . In the example of  FIG. 10 , the cell ID “C1”, the SSID “AP2”, and the last connection time “2011.03.02.09.00” are entered into the fields in the connection table  400  and the connection record  400 - 1  is newly entered as a record. 
     Various process procedures of the communication apparatus  101  according to the first embodiment will be described. A determination process procedure of the communication apparatus  101  will be described in which it is determined whether a track record of connection to the access point APj in the cell Ci in which the communication apparatus  101  is located, is present. 
       FIG. 11  is a flowchart of an example of the determination process procedure of the communication apparatus  101  according to the first embodiment. In the flowchart of  FIG. 11 , first, the detecting unit  501  determines whether the state of the display  303  has transitioned from the non-display state to the display state (step S 1101 ). 
     The detecting unit  501  waits for a transition from the non-display state to the display state of the display  303  (step S 1101 : NO). When the detecting unit  501  determines that a transition from the non-display state to the display state of the display  303  has occurred (step S 1101 : YES), the determining unit  504  acquires from the acquiring unit  502 , the cell ID of the cell Ci in which the communication apparatus is located, among the cells C1 to Cn (step S 1102 ). 
     The determining unit  504  then refers to the connection table  400  to determine whether the SSID of the access point APj that is stored corresponding to the acquired cell ID is present (step S 1103 ). If the SSID is present (step S 1103 : YES), the determining unit  504  sends an ON setting request for the detection operation flag to the communication control unit  505  (step S 1104 ) and ends a series of processes according to this flowchart. 
     On the other hand, if the SSID is not present (step S 1103 : NO), the determining unit  504  sends an OFF setting request for the detection operation flag to the communication control unit  505  (step S 1105 ) and ends the series of processes according to this flowchart. 
     This enables the communication control unit  505  to be notified of an ON/OFF setting request for the detection operation flag, depending on the track record of connection to the access point APj in the cell Ci in which the communication apparatus  101  is located, in response to a transition from the non-display state to the display state of the display  303 . 
     A communication control process procedure of the communication apparatus  101  for controlling the detection operation for the access point APj will be described. 
       FIG. 12  is a flowchart of an example of the communication control process procedure of the communication apparatus  101  according to the first embodiment. In the flowchart of  FIG. 12 , the communication control unit  505  first determines whether a setting request for the detection operation flag has been received from the determining unit  504  (step S 1201 ). 
     The communication control unit  505  waits for reception of a setting request for the detection operation flag (step S 1201 : NO). When a setting request for the detection operation flag is received (step S 1201 : YES), the communication control unit  505  determines whether the received setting request is an ON setting request (step S 1202 ). 
     If the received setting request is an ON setting request (step S 1202 : YES), the communication control unit  505  determines whether the detection operation flag is set to ON (step S 1203 ). If the detection operation flag is set to ON (step S 1203 : YES), the communication control unit  505  ends the series of processes according to this flowchart. 
     If the detection operation flag is set to OFF at step S 1203  (step S 1203 : NO), the communication control unit  505  turns the detection operation flag from OFF to ON (step S 1204 ) and terminates the series of processes according to this flowchart. 
     If the received setting request is an OFF setting request (step S 1202 : NO), the communication control unit  505  determines whether the detection operation flag is set to OFF (step S 1205 ). If the detection operation flag is set to OFF (step S 1205 : YES), the communication control unit  505  ends the series of processes according to this flowchart. 
     On the other hand, if the detection operation flag is set to ON at step S 1205  (step S 1205 : NO), the communication control unit  505  turns the detection operation flag from ON to OFF (step S 1206 ) and terminates the series of processes according to this flowchart. 
     This enables the detection operation for the access point APj to be controlled depending on the track record of connection to the access point APj in the cell Ci in which the communication apparatus  101  is located. 
     An update process procedure of the communication apparatus  101  for updating the contents of the connection table  400  depicted in  FIG. 4  will be described. 
       FIG. 13  is a flowchart of an example of the update process procedure of the communication apparatus  101  according to the first embodiment. In the flowchart of  FIG. 13 , the updating unit  507  first determines whether completion notification concerning connection to the access point APj has been received from the communication control unit  505  (step S 1301 ). 
     The updating unit  507  waits for reception of completion notification concerning connection to the access point APj (step S 1301 : NO). When the updating unit  507  receives the connection completion notification (step S 1301 : YES), the updating unit  507  acquires from the acquiring unit  502 , the cell ID of the cell Ci in which the communication apparatus is located (step S 1302 ). 
     The updating unit  507  then acquires from the communication control unit  505 , the SSID of the access point APj to which connection has been completed (step S 1303 ). The updating unit  507  then refers to the connection table  400  to determine whether connection information corresponding to the acquired cell ID is present (step S 1304 ). 
     If the connection information is not present (step S 1304 : NO), the updating unit  507  acquires the current time (step S 1305 ). The updating unit  507  then enters the acquired cell ID, SSID, and current time into the fields in the connection table  400  (step S 1306 ) and terminates the series of processes according to this flowchart. As a result, new connection information is entered as a record in the connection table  400 . 
     If the connection information is present at step S 1304  (step S 1304 : YES), the updating unit  507  acquires the current time (step S 1307 ). The updating unit  507  enters the acquired SSID and current time into the SSID field and the last connection time field of the connection information corresponding to the acquired cell ID (step S 1308 ), and terminates the series of processes according to this flowchart. 
     Thus, the contents of the connection table  400  can be updated according to the status of connection to the access point APj in the cell Ci in which the communication apparatus  101  is located. 
     As described above, according to the communication apparatus  101  of the first embodiment, when the state of the display  303  transitions from the non-display state to the display state, it can be determined whether a track record of connection to the access point APj in the cell Ci in which the communication apparatus is located exists. According to the communication apparatus  101 , the detection operation for the access point APj can be started if the track record of connection to the access point APj is present. 
     Thus, detection of an available access point APj in a cell Ci having a track record of connection to the access point APj can be performed, without a user input operation, in response to a transition to the state of the display  303 , thereby preventing the usability from being impaired. 
     According to the communication apparatus  101 , in the case of absence of the track record of connection to the access point APj in the cell Ci in which the communication apparatus is located, control can be provided so that the detection operation for the access point APj is not started. This enables the detection operation for an access point APj in a cell Ci that does not have an available access point APj to be suppressed and thereby, achieves a reduction in the power consumption of the communication apparatus  101 . 
     According to the communication apparatus  101 , the detection operation for the access point APj can be suspended if the state of the display  303  transitions from the display state to the non-display state as a result of starting the detection operation for the access point APj. This enables the detection operation for the access point APj to be suppressed when the state of the display  303  is the non-display state and thereby, suppresses the power consumption of the communication apparatus  101 . 
     According to the communication apparatus  101 , in the case of entering new connection information into the connection table  400 , it can be determined whether the total number M of records of connection information entered in the connection table  400  is at least the threshold value M max . According to the communication apparatus  101 , if the total number M is greater than or equal to the threshold value M max , connection information having the oldest last connection time can be deleted from the connection information in the connection table  400 . This enables increases in the number of records in the connection table  400  to be suppressed, thereby enabling increases in the storage area used for the storage of the connection table  400  to be suppressed. 
     A communication apparatus  101  according to a second embodiment will now be described. Similar portions to those described in the first embodiment will not again be described. 
     In the first embodiment  7 , a case has been described where the detection operation for the access point APj is controlled by determining in response to a transition from the non-display state to the display state of the display  303 , whether a track record of connection to the access point APj in the cell Ci in which the communication apparatus  101  is located is present. In this case, the base station BSi to which the communication apparatus  101  connects may be switched and the cell Ci in which the communication apparatus  101  is located may be changed with the state of the display  303  remaining in the display state. 
     Thus, in the second embodiment, when the state of the display  303  transitions from the non-display state to the display state, the communication apparatus  101  starts a detection of switching of the base station BSi to which the communication apparatus connects. The communication apparatus  101  then determines in response to switching of the base station BSi to which the communication apparatus connects, whether a track record of connection to the access point APj in the cell Ci in which the communication apparatus is located exists. As a result, the detection operation for the access point APj can be controlled by determining whether there exists a track record of connection to the access point APj when the cell Ci in which the communication apparatus  101  is located changes with the state of the display  303  being the display state. 
     An example of a functional configuration of the communication apparatus  101  according to the second embodiment will be described.  FIG. 14  is a block diagram of an example of a functional configuration of the communication apparatus  101  according to the second embodiment. In  FIG. 14 , the communication apparatus  101  is configured to include the detecting unit  501 , the acquiring unit  502 , the first communicating unit  503 , the determining unit  504 , the communication control unit  505 , the second communicating unit  506 , the updating unit  507 , and a judging unit  1401 . The detecting unit  501  to the updating unit  507  function as a control unit and are implemented by, for example, causing the CPU  301  to execute a program stored in the memory  302  or by use of hardware such as the public network I/F  305  and the WLAN I/F  306 . Processing results obtained by the functional units are stored to the memory  302 , for example. 
     The judging unit  1401  has a function of starting the execution of a judgment process for judging whether the base station BSi to which the communication apparatus connects is switched when the state of the display  303  transitions from the non-display state to the display state. At this time, to continue the communication with the base station of the mobile communication network, the communication apparatus  101  performs a so-called hand-over, i.e., a process for switching the base station BSi to which the communication apparatus connects among the base stations BS1 to BSn. 
     For example, when the user of the communication apparatus  101  moves, the base station BSi to which the communication apparatus  101  connects may be switched. Even when the user substantially stops, the base station BSi to which the communication apparatus  101  connects may be switched due to a change in the signal strength from the base station of the mobile communication network. 
     The judging unit  1401  judges whether switching of the base station BSi to which the communication apparatus connects occurs by detecting a hand-over performed with respect to the communication apparatus  101 . For example, when the state of the display  303  transitions from the non-display state to the display state, the judging unit  1401  sets a hand-over detection flag to ON. The hand-over flag is a flag indicative of whether to detect for an execution of hand-over in the communication apparatus  101 . The hand-over detection flag is stored in, for example, a register of the memory  302  or the CPU  301 . 
     When the hand-over detection flag is set to ON, the judging unit  1401  detects for a hand-over performed in the communication apparatus  101 . A hand-over detection method is arbitrary. For example, the judging unit  1401  may detect a hand-over if the cell ID acquired by the acquiring unit  502  is different from the most recently acquired cell ID. 
     The determining unit  504  has a function of determining whether there exists a track record of connection to the access point APj in the cell Ci in which the communication apparatus is located if the judging unit  1401  judges that a switching of the base station BSi to which the communication apparatus connects has occurred. For example, the determining unit  504  determines whether there exists a track record of connection to the access point APj in the cell Ci in which the communication apparatus is located if a hand-over is detected after the transition from the non-display state to the display state of the display  303 . 
     Hence, the detection operation for the access point APj can be started if there exists a track record of connection to the access point APj when the cell Ci in which the communication apparatus  101  is located changes as a result of switching of the base station BSi to which the communication apparatus  101  connects. 
     The judging unit  1401  has a function of suspending the execution of a judging process for judging whether the base station BSi to which the communication apparatus connects is switched, if the state of the display  303  transitions from the display state to the non-display state. For example, the judging unit  1401  sets the hand-over detection flag to OFF, if the state of the display  303  transitions from the display state to the non-display state. 
     This can suspend the hand-over detection function for detecting a hand-over when the state of the display  303  transitions from the display state to the non-display state, thereby preventing the determining process of the determining unit  504  from being executed when the state of the display  303  is the non-display state. This can prevent the power consumption by the communication apparatus  101  for execution of the detection operation for the access point APj when the state of the display  303  is the non-display state. 
     The communication control unit  505  may suspend the detection operation for the access point APj, if as a result of start of the detection operation for the access point APj, the determining unit  504  determines detection of a hand-over and no track record of connection to the access point APj. 
     For example, the communication control unit  505  sets the detection operation flag to OFF if as a result of execution of a hand-over with the detection operation flag being set to ON, there exists no track record of connection to the access point APj in the cell Ci in which the communication apparatus is located. This can end the cyclically performed detection operation for the access point APj. 
     The communication control unit  505  may resume the detection operation for the access point APj if as a result of suspension of the detection operation for the access point APj, a hand-over is detected and the determining unit  504  determines that there exists a track record of connection to the access point APj. 
     For example, the communication control unit  505  sets the detection operation flag to ON if as a result of execution of a hand-over with the detection operation flag being set to OFF, there exists a track record of connection to the access point APj in the cell Ci in which the communication apparatus is located. This can resume the cyclically performed detection operation for the access point APj. 
     With reference to  FIGS. 15 to 21 , operation examples of the communication apparatus  101  according to the second embodiment will be described. 
       FIG. 15  is an explanatory view (1) of an operation example of the communication apparatus  101  according to the second embodiment. The operation example of the communication apparatus  101  depicted in  FIG. 15  is an operation example where hand-over to a base station BSi whose cell ID is not in the connection table  400  is detected. 
     (15-1) The detecting unit  501  detects a transition from the non-display state to the display state of the display  303 . In the example of  FIG. 15 , a transition from the non-display state to the display state of the display  303  is detected as a result of switching from the non-display state to the display state of the display  303  through a user input operation. 
     (15-2) Upon detecting a transition from the non-display state to the display state of the display  303 , the detecting unit  501  sends a hand-over detection start request to the judging unit  1401 . In this case, the hand-over detection start request is one requesting the judging unit  1401  to start detecting for a hand-over. 
     (15-3) Upon receiving the hand-over detection start request, the judging unit  1401  returns an Ack to the detecting unit  501  to set the hand-over detection flag to ON. As a result, the judging unit  1401  starts hand-over detection, i.e., a judging process for judging whether the base station BSi to which the communication apparatus  101  connects is switched. 
     (15-4) The determining unit  504  requests the acquiring unit  502  to acquire the cell ID of the cell Ci in which the communication apparatus is located and thereby, acquires the cell ID of the cell Ci in which the communication apparatus  101  is located. In the example of  FIG. 15 , “C1” is acquired as the cell ID of the cell Ci in which the communication apparatus is located. 
     (15-5) The determining unit  504  refers to the connection table  400  to determine whether there exists a track record of connection to the access point APj in the cell Ci in which the communication apparatus is located. In the example of  FIG. 15 , the connection record  400 - 1  corresponding to the acquired cell ID “C1” is already entered and therefore it is determined that there exists a track record of connection to the access point APj. 
     (15-6) The determining unit  504  sends to the communication control unit  505 , an ON setting request for the detection operation flag. At this time, the determining unit  504  may read out a detection operation flag and if the detection operation flag is OFF, send an ON setting request for the detection operation flag to the communication control unit  505 . 
     (15-7) Upon receiving the ON setting request for the detection operation flag, the communication control  505  returns an Ack to the determining unit  504  and if the detection operation flag is OFF, sets the detection operation flag to ON. As a result, the communication control unit  505  controls the communicating units to cyclically perform the detection operation for the access point APj. 
     (15-8) Upon receiving from the communication control unit  505 , completion notification concerning connection to the access point APj, the updating unit  507  updates the contents of the connection table  400 . The specific contents of processes of the updating unit  507  are similar to those of the updating unit  507  depicted in  FIG. 8  and therefore will not again be described. 
     (15-9) When the base station BSi to which the communication apparatus connects is switched, the judging unit  1401  sends hand-over detection notification to the updating unit  507 . The hand-over detection notification includes the cell ID of the switched base station BSi. In the example of  FIG. 15 , a hand-over detection notification that includes the cell ID “C2” of the base station BS2 is sent. 
     (15-10) Upon receiving the hand-over detection notification, the updating unit  507  reads out connection information from the connection table  400 . The order of processes (15-10) and (15-11) is arbitrary. 
     (15-11) The updating unit  507  requests the communication control unit  505  to acquire the SSID of the access point APj the connection to which is completed and thereby, acquires the SSID of the access point APj currently connected. In the example of  FIG. 15 , “AP2” is acquired as the SSID of the access point AP2 currently connected. 
     (15-12) The updating unit  507  updates the contents of the connection table  400 . In the example of  FIG. 15 , connection information corresponding to the cell ID “C2” of the base station BS2 is not entered and hence, a connection record  400 - 2  that corresponds to the cell ID “C2” of the base station BS2 is newly entered. 
     In this manner, according to the communication apparatus  101 , when a hand-over to a base station BSi whose cell ID is not in the connection table  400  has been detected, connection information corresponding to the cell ID of the base station BSi can be newly entered. 
       FIG. 16  is an explanatory view (2) of an operation example of the communication apparatus  101  according to the second embodiment. The operation example of the communication apparatus  101  depicted in  FIG. 16  is an operation example in the case of detection of hand-over to a base station BSi whose cell ID is in the connection table  400 . 
     Operations of (16-1) to (16-11) depicted in  FIG. 16  are similar to those of (15-1) to (15-11) depicted in  FIG. 15  and therefore will not again be described. 
     (16-12) The updating unit  507  updates the contents of the connection table  400 . In the example of  FIG. 16 , the connection record  400 - 2  is already entered that corresponds to a combination of the cell ID “C2” of the base station BS2 in which the communication apparatus  101  is located and the SSID “AP2” of the access point AP2 currently connected. 
     For this reason, the updating unit  507  updates the last connection time of the connection record  400 - 2 . For example, “2011.03.04.09.00” indicating the time of connection of the communication apparatus  101  to the access point AP2 is overwritten into the last connection time field of the connection record  400 - 2 . 
     In this manner, according to the communication apparatus  101 , when a hand-over to a base station BSi whose cell ID is already in the connection table  400  has been detected, connection information can be updated that corresponds to the cell ID of the base station BSi. 
       FIG. 17  is an explanatory view (3) of an operation example of the communication apparatus  101  according to the second embodiment. The operation example of the communication apparatus  101  depicted in  FIG. 17  is an operation example where the hand-over detection function is suspended when the state of the display  303  transitions from the display state to the non-display state. 
     Operations of (17-1) to (17-8) depicted in  FIG. 17  are similar to those of (15-1) to (15-8) depicted in  FIG. 15  and therefore will not again be described. 
     (17-9) The detecting unit  501  detects a transition from the display state to the non-display state of the display  303 . In the example of  FIG. 17 , the transition from the display state to the non-display state of the display  303  is detected as a result of switching from the display state to the non-display state of the display  303  through a user input operation. 
     (17-10) Upon detecting the transition from the display state to the non-display state of the display  303 , the detecting unit  501  sends a hand-over detection suspend request to the judging unit  1401 . The hand-over detection suspend request requests a suspension of execution of a judging process for judging whether a hand-over is performed in the communication apparatus  101 . 
     Upon receiving the hand-over detection suspend request, the judging unit  1401  returns an Ack to the detecting unit  501  to set the hand-over detection flag to OFF. As a result, the judging unit  1401  suspends the hand-over detection, i.e., the execution of the judging process for judging whether the base station BSi to which the communication apparatus  101  connects is switched. 
     In this manner, according to the communication apparatus  101 , the hand-over detection function can be suspended in response to a transition from the display state to the non-display state of the display  303 . 
       FIG. 18  is an explanatory view (4) of an operation example of the communication apparatus  101  according to the second embodiment. The operation example of the communication apparatus  101  depicted in  FIG. 18  is an operation example where in a case of no connection to the access point APj, hand-over to a base station BSi whose cell ID is not in the connection table  400  is detected. 
     Operations of (18-1) to (18-7) depicted in  FIG. 18  are similar to those of (15-1) to (15-7) depicted in  FIG. 15  and therefore will not again be described. 
     (18-8) When the base station BSi to which the communication apparatus connects is switched, the judging unit  1401  sends hand-over detection notification to the determining unit  504 . In the example of  FIG. 18 , hand-over detection notification is sent that includes the cell ID “C2” of the base station BS2. 
     (18-9) The determining unit  504  refers to the connection table  400  to determine whether there exists a track record of connection to the access point APj in the cell Ci in which the communication apparatus is located. In the example of  FIG. 18 , connection information corresponding to the acquired cell ID “C2” is not entered and hence, it is determined that no track record of connection to the access point APj is present. 
     (18-10) The determining unit  504  sends to the communication control unit  505 , an OFF setting request for the detection operation flag. At this time, the determining unit  504  may read out the detection operation flag and if the detection operation flag is ON, send an OFF setting request for the detection operation flag to the communication control unit  505 . 
     (18-11) Upon receiving the OFF setting request for the detection operation, the communication control unit  505  returns an Ack to the determining unit  504  and if the detection operation flag is ON, sets the detection operation flag to OFF. As a result, the communication control unit  505  suspends the detection operation for the access point APj. 
     In this manner, according to the communication apparatus  101 , the detection operation for the access point APj can be suspended if no track record of connection to the access point APj in the cell Ci in which the communication apparatus  101  is located, is present. 
       FIG. 19  is an explanatory view (5) of an operation example of the communication apparatus  101  according to the second embodiment. The operation example of the communication apparatus  101  depicted in  FIG. 19  is an operation example where in the case of no connection to the access point APj, hand-over to a base station BSi whose cell ID is in the connection table  400  is detected. 
     Operations of (19-1) to (19-7) depicted in  FIG. 19  are similar to those of (15-1) to (15-7) depicted in  FIG. 15  and therefore will not again be described. 
     (19-8) When the base station BSi to which the communication apparatus connects is switched, the judging unit  1401  sends hand-over detection notification to the determining unit  504 . In the example of  FIG. 19 , a hand-over detection notification that includes the cell ID “C2” of the base station BS2 is sent. 
     (19-9) The determining unit  504  refers to the connection table  400  to determine whether there exists a track record of connection to the access point APj in the cell Ci in which the communication apparatus is located. In the example of  FIG. 19 , the connection record  400 - 2  corresponding to the acquired cell ID “C2” is already entered and therefore, it is determined that a track record of connection to the access point APj is present. 
     (19-10) The updating unit  507  sends to the communication control unit  505 , a send request for the SSID of the access point APj currently connected. In the example of  FIG. 19 , no response of the SSID is sent consequent to lack of connection to the access point APj. In this case, the updating unit  507  does not update the contents of the connection table  400 . 
     In this manner, even when hand-over to a base station BSi whose cell ID is in the connection table  400  is detected, the communication apparatus  101  does not update the contents of the connection table  400  if there is no connection to the access point APj. 
       FIG. 20  is an explanatory view (6) of an operation example of the communication apparatus  101  according to the second embodiment. In the operation example of the communication apparatus  101  depicted in  FIG. 20 , while the detection operation flag is OFF, hand-over to a base station BSi whose cell ID is not in the connection table  400  is detected. 
     Operations of (20-1) to (20-3) depicted in  FIG. 20  are similar to those of (15-1) to (15-3) depicted in  FIG. 15  and therefore will not again be described. 
     (20-4) The determining unit  504  requests the acquiring unit  502  to acquire the cell ID of the cell Ci in which the communication apparatus is located and thereby, acquires the cell ID of the cell Ci in which the communication apparatus is located. In the example of  FIG. 20 , “C3” is acquired as the cell ID of the cell Ci in which the communication apparatus is located. 
     (20-5) The determining unit  504  refers to the connection table  400  to determine whether there exists a track record of connection to the access point APj in the cell Ci in which the communication apparatus is located. In the example of  FIG. 20 , connection information corresponding to the acquired cell ID “C3” is not entered and hence, it is determined that no track record of connection to the access point APj is present. 
     (20-6) The determining unit  504  sends to the communication control unit  505 , an OFF setting request for the detection operation flag. 
     (20-7) Upon receiving the OFF setting request for the detection operation flag, the communication control unit  505  returns an Ack to the determining unit  504  and if the detection operation flag is ON, sets the detection operation flag to OFF. As a result, the communication control unit  505  suspends the detection operation for the access point APj. 
     (20-8) When the base station BSi to which the communication apparatus connects is switched, the judging unit  1401  sends a hand-over detection notification to the determining unit  504 . In the example of  FIG. 20 , hand-over detection notification including the cell ID “C2” of the base station BS2 is sent. 
     (20-9) Upon receiving the hand-over detection notification, the determining unit  504  refers to the connection table  400  to determine whether there exists a track record of connection to the access point APj in the cell Ci in which the communication apparatus is located. In the example of  FIG. 20 , connection information corresponding to the acquired cell ID “C2” is not entered and hence, it is determined that no track record of connection to the access point APj is present. In this case, the updating unit  507  does not update the contents of the connection table  400 . 
     In this manner, when the detection operation flag is OFF, the communication apparatus  101  does not update the contents of the connection table  400  if hand-over is detected to a base station BSi whose cell ID is not in the connection table  400 . 
       FIG. 21  is an explanatory view (7) of an operation example of the communication apparatus  101  according to the second embodiment. In the operation example of the communication apparatus  101  depicted in  FIG. 21 , while the detection operation flag is OFF, hand-over to a base station BSi whose cell ID is in the connection table  400  is detected. 
     Operations of (21-1) to (21-3) depicted in  FIG. 21  are similar to those of (15-1) to (15-3) depicted in  FIG. 15  and therefore will not again be described. 
     (21-4) The determining unit  504  requests the acquiring unit  502  to acquire a cell ID of the cell Ci in which the communication apparatus is located, to acquire the cell ID of the cell Ci in which the communication apparatus is located. In the example of  FIG. 21 , “C3” is acquired as the cell ID of the cell Ci in which the communication apparatus is located. 
     (21-5) The determining unit  504  refers to the connection table  400  to determine whether there exists a track record of connection to the access point APj in the cell Ci in which the communication apparatus is located. In the example of  FIG. 21 , connection information corresponding to the acquired cell ID “C3” is not entered and hence, it is determined that no track record of connection to the access point APj is present. 
     (21-6) The determining unit  504  sends to the communication control unit  505 , an OFF setting request for the detection operation flag. 
     (21-7) Upon receiving the detection operation flag OFF setting request, the communication control unit  505  returns an Ack to the determining unit  504  and, if the detection operation flag is ON, sets the detection operation flag to OFF. As a result of this, the communication control unit  505  stops the detection operation for the access point APj. 
     (21-8) When the base station BSi to which the communication apparatus connects is switched, the judging unit  1401  sends a hand-over detection notification to the determining unit  504 . In the example of  FIG. 21 , sent is a hand-over detection notification containing the cell ID “C1” of the base station BS2. 
     (21-9) Upon receiving the hand-over detection notification, the determining unit  504  refers to the connection table  400  to determine whether there exists a track record of connection to the access point APj in the cell Ci in which the communication apparatus is located. In the example of  FIG. 21 , the connection record  400 - 1  corresponding to the acquired cell ID “C1” is already entered and hence it is determined that the track record of connection to the access point APj is present. 
     (21-10) The determining unit  504  sends to the communication control unit  505 , an ON setting request for the detection operation flag. 
     (21-11) Upon receiving the detection operation flag ON setting request, the communication control unit  505  returns an Ack to the determining unit  504  and, if the detection operation flag is OFF, sets the detection operation flag to ON. As a result, the communication control unit  505  controls the communicating units so that the detection operation for the access point APj is cyclically performed. 
     In this manner, according to the communication apparatus  101 , the detection operation for the access point APj can be started if there exists a track record of connection to the access point APj in the cell Ci in which the communication apparatus  101  is located when a hand-over is detected. 
     Various process procedures of the communication apparatus  101  according to the second embodiment will then be described. A determination process procedure of the communication apparatus  101  will first be described in which it is determined whether a track record of connection to the access point APj is present in the cell Ci in which the communication apparatus  101  is located. 
       FIG. 22  is a flowchart of an example of the determination process procedure of the communication apparatus  101  according to the second embodiment. In the flowchart of  FIG. 22 , first, the detecting unit  501  determines whether the state of the display  303  transitions from the non-display state to the display state (step S 2201 ). 
     The detecting unit  501  waits for a transition from the non-display state to the display state of the display  303  (step S 2201 : NO). If the detecting unit  501  determines that the state of the display  303  transitions from the non-display state to the display state (step S 2201 : YES), the detecting unit  501  sends a hand-over detection start request to the judging unit  1401  (step S 2202 ). 
     Next, the determining unit  504  acquires from the acquiring unit  502  the cell ID of the cell Ci in which the communication apparatus is located (step S 2203 ). The determining unit  504  then refers to the connection table  400  to determine whether there exists an SSID of the access point APj that is stored corresponding to the acquired cell ID (step S 2204 ). 
     If the SSID is present (step S 2204 : YES), the determining unit  504  sends to the communication control unit  505 , an ON setting request for the detection operation flag (step S 2205 ), and ends the series of processes according to this flowchart. On the other hand, if the SSID is not present (step S 2204 : NO), the determining unit  504  sends to the communication control unit  505 , an OFF setting request for the detection operation flag (step S 2206 ), and ends the series of processes according to this flowchart. 
     This enables a hand-over detection to be started in response to a transition from the non-display state to the display state of the display  303 . The communication control unit  505  can be notified of the detection operation flag ON/OFF setting request depending on the track record of connection to the access point APj in the cell Ci in which the communication apparatus  101  is located. 
     A setting process procedure of the communication apparatus  101  for setting the hand-over detection flag will then be described. 
       FIG. 23  is a flowchart of an example of the setting process procedure of the communication apparatus  101  according to the second embodiment. In the flowchart of  FIG. 23 , first, the judging unit  1401  judges whether a hand-over detection start request is received from the detecting unit  501  (step S 2301 ). 
     If the hand-over detection start request is received (step S 2301 : YES), the judging unit  1401  sets the hand-over detection flag to ON (step S 2302 ), and ends the series of processes according to this flowchart. 
     If the hand-over detection start request is not received at step S 2301  (step S 2301 : NO), the judging unit  1401  judges whether a hand-over detection suspend request has been received from the detecting unit  501  (step S 2303 ). The hand-over detection suspend request is sent from the detecting unit  501  to the judging unit  1401  when the state of the display  303  transitions from the display state to the non-display state. 
     If the hand-over detection suspend request is not received (step S 2303 : NO), the judging unit  1401  returns to step S 2301 . On the other hand, if the hand-over detection suspend request is received (step S 2303 : YES), the judging unit  1401  sets the hand-over detection flag to OFF (step S 2304 ), and ends the series of processes according to this flowchart. 
     This enables the hand-over detection function to be controlled depending on the transition of the state of the display  303 . 
     An update process procedure of the communication apparatus  101  will next be described that updates the contents of the connection table  400  depicted in  FIG. 4 . 
       FIGS. 24 and 25  are flowcharts of an example of the update process procedure of the communication apparatus  101  according to the second embodiment. In the flowchart of  FIG. 24 , first, the updating unit  507  judges whether a hand-over detection notification has been received from the judging unit  1401  (step S 2401 ). The hand-over detection notification is sent from the judging unit  1401  to the updating unit  507  when the base station BSi to which the communication apparatus connects is switched. 
     The updating unit  507  waits for a reception of the hand-over detection notification (step S 2401 : NO). When the updating unit  507  receives a hand-over detection notification (step S 2401 : YES), the updating unit  507  acquires from the acquiring unit  502  a cell ID of the cell Ci in which the communication apparatus is located (step S 2402 ). 
     The updating unit  507  reads out a detection operation flag (step S 2403 ) to judge whether the detection operation flag is set to ON (step S 2404 ). If the detection operation flag is set to OFF (step S 2404 : NO), the determining unit  504  refers to the connection table  400  to determine whether connection information corresponding to the acquired cell ID is present (step S 2405 ). 
     If the connection information corresponding to the cell ID is present (step S 2405 : YES), the determining unit  504  sends to the communication control unit  505 , an ON setting request for the detection operation flag (step S 2406 ), and ends the series of processes according to this flowchart. On the other hand, if the connection information corresponding to the cell ID is not present (step S 2405 : NO), the determining unit  504  terminates the series of processes according to this flowchart. 
     If the detection operation flag is set to ON at step S 2404  (step S 2404 : YES), the updating unit  507  transitions to step S 2501  depicted in  FIG. 25 . 
     In the flowchart depicted in  FIG. 25 , first, the updating unit  507  sends to the communication control unit  505 , an acquisition request for the SSID of the access point APj currently connected (step S 2501 ). The updating unit then judges whether the SSID of the access point APj currently connected has been acquired from the communication control unit  505  (step S 2502 ). 
     If the SSID has not been acquired due to no-connection to the access point AP (step S 2502 : NO), the determining unit  504  refers to the connection table  400  and determines whether connection information corresponding to the acquired cell ID is present (step S 2503 ). 
     If no connection information corresponding to the cell ID is present (step S 2503 : NO), the determining unit  504  sends to the communication control unit  505 , an OFF setting request for the detection operation flag (step S 2504 ), and terminates the series of processes according to this flowchart. On the other hand, if the connection information corresponding to the cell ID is present (step S 2503 : YES), the determining unit  504  ends the series of processes according to this flowchart. 
     If the SSID is acquired at step S 2502  (step S 2502 : YES), the updating unit  507  refers to the connection table  400  and determines whether connection information corresponding to the acquired cell ID is present (step S 2505 ). 
     If connection information is present (step S 2505 : YES), the updating unit  507  acquires the current time (step S 2506 ). The updating unit  507  enters the acquired SSID and the current time into the SSID field and the last connection time field of the connection information corresponding to the acquired cell ID (step S 2507 ), and terminates the series of processes according to this flowchart. 
     If no connection information is present at step S 2505  (step S 2505 : NO), the updating unit  507  acquires the current time (step S 2508 ). The updating unit  507  enters the acquired cell ID, the SSID, and the current time into the respective fields in the connection table  400  (step S 2509 ), and terminates the series of processes according to this flowchart. As a result, new connection information is entered as a record in the connection table  400 . 
     This enables the contents of the connection table  400  to be updated depending on the status of connection to the access point APj when hand-over is performed. 
     The communication control process procedure of the communication apparatus  101  for controlling the detection operation for the access point APj is similar to the communication control process procedure (see  FIG. 12 ) of the communication apparatus  101  described in the first embodiment and therefore will not again be described. The update process procedure of the communication apparatus  101  upon the completion of connection to the access point APj is similar to the update process procedure of the communication apparatus  101  described in the first embodiment and therefore will not again be described. 
     As described above, according to the communication apparatus  101  of the second embodiment, the detection of hand-over performed by the communication apparatus can be started if the state of the display  303  transitions from the non-display state to the display state. According to the communication apparatus  101 , if hand-over is detected, it can be determined whether a track record of connection to the access point APj in the cell Ci in which the communication apparatus is located is present. 
     This enables the detection operation for the access point APj to be started if a track record of connection to the access point APj is present when the cell Ci in which the communication apparatus  101  is located is changed as a result of switching of the base station BSi to which the communication apparatus  101  connects. That is, even though the cell Ci in which the communication apparatus  101  is located is changed while the state of the display  303  remains in the display state, the detection operation can be started depending on the track record of connection to the access point APj, thereby making it possible to prevent usability from being impaired. 
     According to the communication apparatus  101 , the detection of hand-over performed by the communication apparatus can be suspended if the state of the display  303  transitions from the display state to the non-display state. This can prevent power consumption by the communication apparatus  101  for execution of the detection operation for the access point APj when the state of the display  303  is the non-display state. 
     According to the communication apparatus  101 , the detection operation for the access point APj can be suspended if, as a result of starting the detection operation for the access point APj, hand-over is detected and if it is determined that a track record of connection to the access point APj is not present. This enables the cyclically performed detection operation for the access point APj to be suspended if the cell Ci in which the communication apparatus  101  is located changes to a cell having no track record of connection to the access point APj as a result of execution of the hand-over. 
     According to the communication apparatus  101 , the detection operation for the access point APj can be resumed if, as a result of suspending the detection operation for the access point APj, hand-over is detected and if it is determined that a track record of connection to the access point APj is present. This enables the cyclically performed detection operation for the access point APj to be resumed if the cell Ci in which the communication apparatus  101  is located changes to a cell having a track record of connection to the access point APj as a result of execution of the hand-over. 
     A communication apparatus  101  according to a third embodiment will be described. Similar portions to those described in the first and second embodiments will not again be described. 
     A storage area used to store the connection table  400  increases as the number of records in the connection table  400  increases. In a case where the access point APj to which the communication apparatus  101  connects is portable or equipped on a train and/or bus, frequent hand-over is performed accompanying the movement of the train and/or the bus, which may result in a sharp increase in the number of records in the connection table  400 . 
     Thus, in the third embodiment, an updating method will be described that suppresses increases in the number of records in the connection table  400  and that suppresses increases of the storage area used for the storage of the connection table  400 . Examples of a first updating method and a second updating method of the connection table  400  according to the third embodiment will hereinafter be described. 
     An example of the first updating method will be described. In the first updating method, ESSID is used as identification information for identifying an access point APj of the wireless LAN. 
       FIG. 26  is an explanatory view (2) of an example of the contents of the connection table  400 . In  FIG. 26 , the connection table  400  has fields for cell IDs, ESSIDs, and last connection times. By entering information into each of the fields, connection information is stored as records (e.g., connection records  2600 - 1  to  2600 - 6 ). 
     The ESSID is identification information for identifying the access point APj of the wireless LAN. The same ESSID may be imparted to a specific access point group among access points AP1 to APm. An example of a specific access point group is a set of access points having the same available communication services or a set of access points provided respectively at stores managed by a company. 
     An example of the contents of specific processes of the updating unit  507  will be described in a case where connection information is newly entered into the connection table  400  depicted in  FIG. 26  as a result of completion of connection to the access point APj. An example will be described in which connection information including the cell ID “C6”, the ESSID “ESSID-1”, and the last connection time “2011.03.02.09.15” is newly entered. 
     In this case, first, the updating unit  507  retrieves from the connection table  400 , connection information having in the ESSID field, the same ESSID as the ESSID “ESSID-1” of the connection information to be newly entered. In the example of  FIG. 26 , connection records  2600 - 1  to  2600 - 5  having “ESSID-1” in the ESSID field are retrieved. 
     The updating unit  507  then calculates the number N of retrieved connection records. In the example of  FIG. 26 , the number N of retrieved connection records is “N=5”. The updating unit  507  judges whether the calculated number N is at least a threshold value N max . The threshold value N max  represents an upper limit value of the number of connection records that can be entered into the connection table  400  for the same ESSID. The threshold value N max  can be arbitrarily set and, for example, stored in the preset memory  302 . In this case, the threshold value N max  is “N max =5”. 
     If the number N is less than the threshold value N max , the updating unit  507  enters new connection information into the connection table  400 . On the other hand, if the number N is not less than the threshold value N max , the updating unit  507  deletes connection information having the oldest last connection time from the retrieved connection information in the connection table  400 . The updating unit  507  then enters new connection information into the connection table  400 . 
     In the example of  FIG. 26 , the number N is not less than the threshold value N max . Hence, the updating unit  507  deletes from the connection table  400 , the connection record  2600 - 1  having the oldest last connection time among the retrieved connection records  2600 - 1  to  2600 - 5 . The updating unit  507  then enters new connection information into the connection table  400 . 
     In this manner, according to the first updating method, an increase in the number of records in the connection table  400  can be suppressed by setting an upper limit on the total number N of connection records that can be entered into the connection table  400  for the same ESSID. 
     An update process procedure of the communication apparatus  101  according to the first updating method will be described. The update process procedure of the communication apparatus  101  will be described in the case of completion of connection to the access point APj. 
       FIG. 27  is a flowchart of an example of the update process procedure of the communication apparatus  101  according to the first updating method when connection to the access point APj is completed. In the flowchart of  FIG. 27 , the updating unit  507  judges whether completion notification of connection to the access point APj has been received from the communication control unit  505  (step S 2701 ). 
     The updating unit  507  waits for reception of completion notification of connection to the access point APj (step S 2701 : NO). Upon receiving connection completion notification (step S 2701 : YES), the updating unit  507  acquires from the acquiring unit  502 , the cell ID of the cell Ci in which the communication apparatus is located (step S 2702 ). 
     The updating unit  507  acquires from the communication control unit  505 , the ESSID of the access point APj to which connection has been completed (step S 2703 ). The updating unit  507  refers to the connection table  400  to judge whether connection information corresponding to the acquired cell ID is present (step S 2704 ). 
     If no connection information is present (step S 2704 : NO), the updating unit  507  executes a first update process (step S 2705 ), and terminates the series of processes according to this flowchart. A specific process procedure of the first update process will be described later with reference to  FIG. 28 . 
     If connection information is present at step S 2704  (step S 2704 : YES), the updating unit  507  acquires the current time (step S 2706 ). The updating unit  507  enters the acquired ESSID and the current time into the ESSID field and the last connection time field of the connection information corresponding to the acquired cell ID (step S 2707 ), and terminates the series of processes according to this flowchart. 
       FIG. 28  is a flowchart of an example of a specific process procedure of the first update process. In the flowchart of  FIG. 28 , the updating unit  507  acquires the current time (step S 2801 ). 
     The updating unit  507  retrieves from the connection table  400 , connection information corresponding to the ESSID acquired at step S 2703  depicted in  FIG. 27  (step S 2802 ). The updating unit  507  calculates the number N of retrieved connection records (step S 2803 ). 
     The updating unit  507  judges whether the calculated number N is at least the threshold value N max  (step S 2804 ). If the number N is less than the threshold value N max  (step S 2804 : NO), the updating unit  507  enters the acquired cell ID, ESSID, and the current time into the fields in the connection table  400  (step S 2805 ), terminates the series of processes according to this flowchart, and returns to the step invoking the first update process. As a result, new connection information is entered as a record into the connection table  400 . 
     On the other hand, if the number N is at least the threshold value N max  (step S 2804 : YES), the updating unit  507  deletes from the connection table  400 , the connection record having the oldest last connection time among the retrieved connection records (step S 2806 ), and transitions to step  2805 . 
     An update process procedure of the communication apparatus  101  will be described in a case of detection of hand-over. 
       FIGS. 29 and 30  are flowcharts of an example of the update process procedure of the communication apparatus  101  according to the first updating method when hand-over is detected. In the flowchart of  FIG. 29 , the updating unit  507  judges whether hand-over detection notification has been received from the judging unit  1401  (step S 2901 ). 
     The updating unit  507  waits for reception of hand-over detection notification (step S 2901 : NO). Upon receiving hand-over detection notification (step S 2901 : YES), the updating unit  507  acquires from the acquiring unit  502 , the cell ID of the cell Ci in which the communication apparatus is located (step S 2902 ). 
     The updating unit  507  reads out a detection operation flag (step S 2903 ) and determines whether the detection operation flag is set to ON (step S 2904 ). If the detection operation flag is set to OFF (step S 2904 : NO), the determining unit  504  refers to the connection table  400  and determines whether connection information corresponding to the acquired cell ID is present (step S 2905 ). 
     If connection information corresponding to the cell ID is present (step S 2905 : YES), the determining unit  504  sends to the communication control unit  505 , an ON setting request for the detection operation flag (step S 2906 ), and terminates the series of processes according to this flowchart. On the other hand, if no connection information corresponding to the cell ID is present (step S 2905 : NO), the determining unit  504  ends the series of processes of according to the flowchart. 
     If the detection operation flag is set to ON at step S 2904  (step S 2904 : YES), the updating unit  507  transitions to step S 3001  depicted in  FIG. 30 . 
     In the flowchart depicted in  FIG. 30 , the updating unit  507  sends to the communication control unit  505 , an acquisition request for the ESSID of the access point APj currently connected (step S 3001 ). The updating unit  507  judges whether the ESSID of the access point APj currently connected has been acquired from the communication control unit  505  (step S 3002 ). 
     If the ESSID has not been acquired due to no-connection to the access point APj (step S 3002 : NO), the determining unit  504  refers to the connection table  400  and determines whether connection information corresponding to the acquired cell ID is present (step S 3003 ). 
     If no connection information corresponding to the cell ID is present (step S 3003 : NO), the determining unit  504  sends to the communication control unit  505 , an OFF setting request for the detection operation flag (step S 3004 ), and terminates the series of processes according to this flowchart. On the other hand, if connection information corresponding to the cell ID is present (step S 3003 : YES), the determining unit  504  ends the series of processes according to this flowchart. 
     If the ESSID is acquired at step S 3002  (step S 3002 : YES), the updating unit  507  refers to the connection table  400  and determines whether connection information corresponding to the acquired cell ID is present (step S 3005 ). 
     If connection information is present (step S 3005 : YES), the updating unit  507  acquires the current time (step S 3006 ). The updating unit  507  enters the acquired ESSID and the current time into the ESSID field and the last connection time field of the connection information corresponding to the acquired cell ID (step S 3007 ), and terminates the series of processes according to this flowchart. 
     If no connection information is present at step S 3005  (S 3005 : NO), the updating unit  507  executes the first update process (step S 3008 ), and terminates the series of processes according to this flowchart. As a result, new connection information is entered as a record into the connection table  400 . 
     The specific process procedure of the first update process executed at step S 3008  is similar to the specific process procedure of the first update process depicted in  FIG. 28  and therefore will not again be described. 
     According to the first updating method described above, an upper limit can be set for the total number N of connection records that can be entered into the connection table for the same ESSID. As a result, according to the first updating method, increases in the number of records in the connection table  400  can be suppressed together with increases in the storage area used to store the connection table  400 . 
     An example of a second updating method will be described. In the second updating method, a combination of the ESSID and the BSSID is used as identification information for identifying the access point APj of the wireless LAN. 
       FIG. 31  is an explanatory view (3) of an example of the contents of the connection table  400 . In  FIG. 31 , the connection table  400  has fields for cell IDs, ESSIDs, BSSIDs, and last connection times. By entering information into the fields connection information is stored as records (e.g., connection records  3100 - 1  to  3100 - 5 ). 
     The BSSID is identification information for uniquely identifying the access point APj of the wireless LAN. The BSSID is for example a media access control (MAC) address of the access point APj. 
     An example of the contents of a specific process of the updating unit  507  will be described for a case where connection information is newly entered into the connection table  400  depicted in  FIG. 31  as a result of completion of connection to the access point APj. An example will be described in which connection information including the cell ID “C6”, the ESSID “ESSID-1”, the BSSID “01:23:45:67:89:A6” and the last connection time “2011.05.07.11.34” is newly entered. 
     In this case, the updating unit  507  retrieves from the connection table  400 , connection information having in the ESSID field, the same ESSID as the ESSID “ESSID-1” of the connection information to be newly entered and having in the BSSID field, the same BSSID as the BSSID “01:23:45:67:89:A6” of the connection information to be newly entered. 
     In other words, the updating unit  507  retrieves from the connection table  400 , connection information having the same combination of the ESSID and the BSSID as that of the connection information to be newly entered. In the example of  FIG. 31 , since no connection information is present that has the same combination of the ESSID and the BSSID as that of the connection information to be newly entered, no connection information is retrieved. 
     In this case, the updating unit  507  calculates the total number M of the connection records stored in the connection table  400 . The updating unit  507  then judges whether the calculated total number M is at least a threshold value M max . If the total number M is less than the threshold value M max , the updating unit  507  enters new connection information in the connection table  400 . 
     On the other hand, if the total number M is not less than the threshold value M max , the updating unit  507  deletes the connection record having the oldest last connection time among the connection records stored in the connection table  400 . The updating unit  507  then enters new connection information into the connection table  400 . In the example of  FIG. 31 , if the total number M is at least the threshold value M max , the updating unit  507  deletes the connection record  3100 - 1  having the oldest last connection time in the connection table  400  and enters new connection information. 
     In this manner, according to the second updating method, an upper limit value is set for the total number M of the connection records that can be into the connection table  400  so that the number of records in the connection table  400  can be prevented from increasing beyond the upper limit value. 
     With reference to  FIG. 32 , a case will be described where in the connection table  400 , connection information having the same combination of the ESSID and the BSSID as that of connection information to be newly entered is present. 
       FIG. 32  is an explanatory view (4) of an example of the contents of the connection information  400 . In  FIG. 32 , the connection table  400  has fields for cell IDs, ESSIDs, BSSIDs, and last connection times. By entering information into the fields, connection information is stored as records (e.g., connection records  3200 - 1  to  3200 - 5 ). 
     An example of the contents of a specific process of the updating unit  507  will hereinafter be described for a case where connection information is newly entered to the connection table  400  depicted in  FIG. 32  as a result of completion of connection to the access point APj. An example will be described in which connection information including the cell ID “C6”, the ESSID “ESSID-1”, the BSSID “01:23:45:67:89:A1” and the last connection time “2011.05.07.11.34” is newly entered. 
     The updating unit  507  retrieves from the connection table  400 , connection information having the same combination of the ESSID and the BSSID as that of the connection information to be newly entered. In the example of  FIG. 32 , connection record s 3200 - 1  to  3200 - 5  having the same combination of the ESSID and the BSSID as that of connection information to be newly entered are retrieved. 
     The updating unit  507  calculates the number N of retrieved connection records. In the example of  FIG. 32 , the number N of retrieved connection records is “N=5”. The updating unit  507  determines whether the calculated number N is at least the threshold value N max . The threshold value N max  represents an upper limit value of the number of the connection records that can be into the connection table  400  for the same combination of the ESSID and the BSSID. The threshold value N max  can be arbitrarily set. In this case, the threshold value N max  is “N max =5”. 
     Accordingly, in the example of  FIG. 32 , the number N is not less than the threshold value N max . In this case, the updating unit  507  deletes from the connection table  400 , the connection record  3200 - 1  having the oldest last connection time among the retrieved connection records  3200 - 1  to  3200 - 5 . The updating unit  507  then enters new connection information into the connection table  400 . 
     In this manner, according to the second updating method, an upper limit is set for the total number N of connection records that can be entered into the connection table  400  for the same combination of the ESSID and the BSSID so that the number of records in the connection table  400  can be prevented from increasing beyond the upper limit value. 
     An update process procedure of the communication apparatus  101  according to the second updating method will be described. The update process procedure of the communication apparatus  101  will be described in a case of completion of connection to the access point APj. 
       FIG. 33  is a flowchart of an example of the update process procedure of the communication apparatus  101  according to the second updating method when connection to the access point APj is completed. In the flowchart of  FIG. 33 , first, the updating unit  507  judges whether completion notification of connection to the access point APj has been received from the communication control unit  505  (step S 3301 ). 
     The updating unit  507  waits for reception of completion notification of connection to the access point APj (step S 3301 : NO). Upon receiving connection completion notification (step S 3301 : YES), the updating unit  507  acquires from the acquiring unit  502 , the cell ID of the cell Ci in which the communication apparatus is located (step S 3302 ). 
     The updating unit  507  acquires from the communication control unit  505 , the ESSID and the BSSID of the access point APj to which connection is completed (step S 3303 ). The updating unit  507  refers to the connection table  400  and determines whether connection information corresponding to the acquired cell ID is present (step S 3304 ). 
     If no connection information is present (step S 3304 : NO), the updating unit  507  executes a second update process (step S 3305 ), and terminates the series of processes according to this flowchart. A specific process procedure of the second update process will be described later with reference to  FIG. 34 . 
     If connection information is present at step S 3304  (step S 3304 : YES), the updating unit  507  acquires the current time (step S 3306 ). The updating unit  507  then enters the acquired ESSID, BSSID, and current time into the ESSID field, the BSSID field, and the last connection time field of the connection information corresponding to the acquired cell ID (step S 3307 ), and terminates the series of processes according to this flowchart. 
       FIG. 34  is a flowchart of an example of the specific process procedure of the second update process. In the flowchart of  FIG. 34 , the updating unit  507  acquires the current time (step S 3401 ). 
     The updating unit  507  retrieves from the connection table  400 , connection information corresponding to the combination of the ESSID and the BSSID acquired at step S 3303  depicted in  FIG. 33  (step S 3402 ). The updating unit  507  calculates the number N of retrieved connection records (step S 3403 ). 
     The updating unit  507  then judges whether the calculated number N is at least the threshold value N max  (step S 3404 ). If the number N is less than the threshold value N max  (step S 3404 : NO), the updating unit  507  calculates the total number M of the connection records stored in the connection table  400  (step S 3405 ). 
     The updating unit  507  judges whether the calculated total number M is at least the threshold value M max  (step S 3406 ). If the total number M is less than the threshold value M max  (step S 3406 : NO), the updating unit  507  transitions to step S 3408 . On the other hand, if the total number M is at least the threshold value M max  (step S 3406 : YES), the updating unit  507  deletes the connection record having the oldest last connection time among the connection records in the connection table  400  (step S 3407 ). 
     The updating unit  507  then enters the acquired cell ID, ESSID, BSSID, and current time into the fields in the connection table  400  (step S 3408 ), terminates the series of processes according to this flowchart, and returns to the step invoking the second update process. As a result, new connection information is entered as a record into the connection table  400 . 
     If the number N is at least the threshold value N max  at step S 3404  (step S 3404 : YES), the updating unit  507  deletes from the connection table  400 , the connection record having the oldest last connection time among the retrieved connection records (step S 3409 ), and transitions to step  3408 . 
     An update process procedure of the communication apparatus  101  will be described in a case of detection of hand-over. 
       FIGS. 35 and 36  are flowcharts of an example of the update process procedure of the communication apparatus  101  according to the second updating method when hand-over is detected. In the flowchart of  FIG. 35 , the updating unit  507  judges whether hand-over detection notification has been received from the judging unit  1401  (step S 3501 ). 
     The updating unit  507  waits for reception of hand-over detection notification (step S 3501 : NO). Upon receiving hand-over detection notification (step S 3501 : YES), the updating unit  507  acquires from the acquiring unit  502 , the cell ID of the cell Ci in which the communication apparatus is located (step S 3502 ). 
     The updating unit  507  reads out a detection operation flag (step S 3503 ) and determines whether the detection operation flag is set to ON (step S 3504 ). If the detection operation flag is set to OFF (step S 3504 : NO), the determining unit  504  refers to the connection table  400  and determines whether connection information corresponding to the acquired cell ID is present (step S 3505 ). 
     If connection information corresponding to the cell ID is present (step S 3505 : YES), the determining unit  504  sends to the communication control unit  505 , an ON setting request for the detection operation flag (step S 3506 ), and terminates the series of processes according to this flowchart. On the other hand, if no connection information corresponding to the cell ID is present (step S 3505 : NO), the determining unit  504  ends the series of processes according to this flowchart. 
     If the detection operation flag is set to ON at step S 3504  (step S 3504 : YES), the updating unit  507  transitions to step S 3601  depicted in  FIG. 36 . 
     In the flowchart depicted in  FIG. 36 , the updating unit  507  sends to the communication control unit  505 , an acquisition request for the ESSID and the BSSID of the access point APj currently connected (step S 3601 ). The updating unit  507  judges whether the ESSID and the BSSID of the access point APj currently connected has been acquired from the communication control unit  505  (step S 3602 ). 
     If the ESSID and the BSSID have not been acquired due to no-connection to the access point APj (step S 3602 : NO), the determining unit  504  refers to the connection table  400  and determines whether connection information corresponding to the acquired cell ID is present (step S 3603 ). 
     If no connection information corresponding to the cell ID is present (step S 3603 : NO), the determining unit  504  sends to the communication control unit  505 , an OFF setting request for the detection operation flag (step S 3604 ), and terminates the series of processes according to this flowchart. On the other hand, if connection information corresponding to the cell ID is present (step S 3603 : YES), the determining unit  504  ends the series of processes according to this flowchart. 
     If the ESSID and the BSSID are acquired at step S 3602  (step S 3602 : YES), the updating unit  507  refers to the connection table  400  and determines whether connection information corresponding to the acquired cell ID is present (step S 3605 ). 
     If connection information is present (step S 3605 : YES), the updating unit  507  acquires the current time (step S 3606 ). The updating unit  507  enters the acquired ESSID, BSSID, and the current time into the ESSID field, the BSSID field, and the last connection time field of the connection information corresponding to the acquired cell ID (step S 3607 ), and terminates the series of processes according to this flowchart. 
     If no connection information is present at step S 3605  (S 3605 : NO), the updating unit  507  executes the second update process (step S 3608 ), and terminates the series of processes according to this flowchart. As a result, new connection information is entered as a record into the connection table  400 . 
     The specific process procedure of the second update process executed at step S 3608  is similar to the specific process procedure of the second update process depicted in  FIG. 34  and therefore will not again be described. 
     According to the second updating method described above, an upper limit can be set for the total number N of connection records that can be entered into the connection  400  for the same combination of the ESSID and the BSSID. According to the second updating method, an upper limit value can be set for the total number M of connection records that can be entered into the connection table  400 . 
     As described, according to the second updating method, the number of records in the connection table  400  can be prevented from increasing beyond the upper limit value, while suppressing increases in the storage area used to store the connection table  400 . 
     The communication control methods described in the embodiments can be implemented by executing on a computer such as a personal computer or a workstation, preliminarily prepared programs. The present communication control program is stored to a computer-readable storage medium such as a hard disk, a flexible disk, a CD-ROM, an MO, and a DVD and is executed by being readout from the medium by the computer. This communication control program may be distributed via a network such as the Internet. 
     All examples and conditional language provided herein are intended for pedagogical purposes of aiding the reader in understanding the invention and the concepts contributed by the inventor to further the art, and are not to be construed as limitations to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although one or more embodiments of the present invention have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.