JP2008017332A - Wireless communication terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless communication terminal capable of efficiently executing scanning of peripheral access points by reducing the power consumed by the scanning of the peripheral access points. <P>SOLUTION: The wireless communication terminal 100 does not positively search the peripheral access point AP under an environment such as a coffee shop CA and a home HM wherein stable communication is executed, but positively searches the peripheral access point AP under an environment such as operation in a hotel HT causing possibility of unstable communication. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a wireless communication terminal device used for a wireless LAN.

  As is well known, a conventional wireless communication terminal device used for a wireless LAN, that is, a so-called station, searches for a nearby access point during a timing at which the access point periodically transmits a beacon. In this method, since information on peripheral access points is periodically acquired, the connection destination change process can be performed at a relatively high speed. Since the search is performed, the power consumption is increased as compared with the case of sleeping without performing this search. In particular, when connected to a wireless LAN access point for personal use, the station is often the only connection destination of the access point. It will not be done.

  As another access point search method, there is a method of searching for peripheral access points when it is determined that communication with a wirelessly connected access point becomes difficult or disconnected. However, with this method, the idle period can be maximized to reduce power consumption, but searching for neighboring access points is performed after communication becomes difficult, so it takes time to recover the connection. was there.

  On the other hand, in order to obtain good communication quality, there is a conventional technique for performing roaming switching to an access point having a high quality environmental condition in a short time and improving the completion rate. (For example, refer to Patent Document 1). In the technique disclosed in this document, two access points AP2-A. 2-B directly notifies AP information necessary for roaming of handset 1 in response to the search received from handset 1, while handset 1 uses peripheral scan, active scan, and the like for peripheral AP 2-B. The latest AP information is actively acquired by executing a search at short time intervals and recorded in the AP information table. As a result, only the latest information of the peripheral AP2-B that can be connected as a roaming destination can be recorded in the AP information table. Furthermore, order conditions for selecting a roaming destination AP in the slave unit 1 are set in advance. Accordingly, the roaming completion probability of the peripheral AP 2-B determined in the first selection is high, so that the roaming is completed in a shorter time.

  In another conventional technique (for example, see Patent Document 2), the station performs the background scan process in each of all the periods for one period in which the background scan process and its own communication are performed. Instead, when the background scan process is performed in one period, the background scan process is not performed in the next one or more periods. In this way, by performing background scanning only in one of a plurality of cycles, the time that the station itself can use for communication is greatly increased when viewed over a plurality of cycles. By reducing the communication time used for the background scan, the communication performed by the station is not adversely affected.

However, in any of the conventional techniques, the case where the wireless LAN is used for a battery-powered portable device is not considered, and there is a problem that a large amount of power is spent for searching for peripheral access points.
JP 2004-088592 A. JP2005-303525A.

In the conventional wireless communication terminal device, there is a problem that a large amount of power is spent searching for peripheral access points.
The present invention has been made to solve the above problems, and provides a wireless communication terminal device capable of reducing the power consumed for searching for peripheral access points and efficiently searching for peripheral access points. Objective.

  In order to achieve the above object, the present invention provides a wireless communication terminal apparatus that wirelessly communicates with an access point accommodated in a LAN and performs communication via the LAN, and a communication means that wirelessly communicates with the access point, and the communication means Search means for searching for an access point other than the access point with which the communication means is performing wireless communication at a frequency according to the access point type determined by the determination means, and a determination means for determining the type of the access point with which the wireless communication is performed And a control means for controlling the communication means to connect to the access point based on the search result of the search means.

As described above, according to the present invention, the type of access point for wireless communication is determined, and other access points are searched at a frequency according to the determination result.
Therefore, according to the present invention, the peripheral access point can be searched at a frequency suitable for the type of the connected access point, so that the power consumed for searching the peripheral access point can be reduced and the peripheral access point can be reduced. It is possible to provide a wireless communication terminal device that can efficiently perform the search.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a configuration of a wireless LAN system in which a wireless communication terminal device 100 according to an embodiment of the present invention is used. A plurality of access points AP11, AP12, and AP13 that can be freely used are installed in the hotel HT, and these exist on the same network and can roam with each other. In the coffee shop CA, an access point AP20 that can be used by users who have become members in advance is installed. In the home HM where the user resides, an access point AP30 for personal use that can be used only by the user is installed.

  Any of these access points AP11, AP12, AP13, AP20, and AP30 are accommodated in a network such as the Internet, and the wireless communication terminal device 100 performs wireless communication with a communicable access point AP as the user moves. And connect to the Internet.

FIG. 2 shows a configuration diagram of the wireless communication terminal device 100. The wireless communication terminal device 100 includes an antenna 1, a communication unit 10, a voice processing unit 20, a display unit 30, an operation unit 40, a notification unit 50, a storage unit 60, and a control unit 70. .
The antenna 1 receives a radio signal transmitted from the above-described access point and transmits a radio signal addressed to the access point from the radio communication terminal apparatus.

  The communication unit 10 wirelessly communicates with the access point through the antenna 1 and performs IP (Internet Protocol) communication through the access point. Specifically, the communication unit 10 down-converts and demodulates the radio signal received by the antenna 1, obtains encoded audio data transmitted from the communication partner station, and transmits this to the audio processing unit 20 through the control unit 70. Output to. Further, the communication unit 10 modulates a baseband signal using the encoded audio data provided from the audio processing unit 20 through the control unit 70, up-converts the baseband signal, generates a radio signal, and transmits the radio signal to the access point through the antenna 1. Send to.

  The audio processing unit 20 decodes the encoded audio data demodulated by the communication unit 10 to reproduce the audio signal, and outputs the sound from the built-in speaker 21. Thereby, the transmitted voice from the call partner station is transmitted to the user. The audio processing unit 20 encodes the audio signal input from the built-in microphone 22 to generate encoded audio data, and supplies the encoded audio data to the communication unit 10 through the control unit 70.

  The display unit 30 is a display device using an LCD (Liquid Crystal Display) or the like, and displays various visual information such as text and images to the user. The operation unit 40 includes a plurality of key switches and the like and receives user requests. The notification unit 50 notifies the user of the occurrence of an incoming call by sound.

  The storage unit 60 stores the phone book data in which the control program of the control unit 70, the control data, the phone number, the name, and the face photo are associated with each other, and the transmitted / received mail data and the access points AP11, AP12, Data for connecting to AP13, AP20, and AP30, and connection data that summarizes data used after connection are stored. FIG. 3 shows a part of the connection data.

  As shown in FIG. 3, the connection data is associated with the ID of each access point AP (hereinafter referred to as access point ID), and whether or not the MAC address, communication method, channel used, and shared key are set (present In this case, a shared key), a connection setting method, an authentication method, a scanning method, and the like are stored. In the connection setting method, “public” means that communication can be made via the network by obtaining predetermined procedures such as authentication and charging method for using the wireless LAN after connecting with easy procedures. It is used in an environment such as a hotel HT operated by an unspecified number of people. Here, it is assumed that the access points AP11, AP12, and AP13 correspond to “public”.

  Further, “manual setting” means a connection form in which a user can connect a parameter such as a shared key given by becoming a member in advance by manually setting necessary information from the operation unit 40. To do. Here, it is assumed that the access point AP20 of the coffee shop CA corresponds to “manual setting”.

  “Automatic setting” automatically sets the identification name of the access point AP, the encryption key used for communication, etc. using software attached to the wireless communication terminal device, and other information is displayed. This means a setting that allows easy connection when the user inputs necessary information from the operation unit 40 in accordance with an instruction displayed on the unit 30. Here, it is assumed that the access point AP30 of the house HM corresponds to “automatic setting”.

  The control unit 70 controls each unit of the wireless communication terminal device, and operates according to a control program and control data stored in the storage unit 60. For example, the control unit 70 receives the incoming signal from the access point AP according to the SIP (Session Initiation Protocol) and controls the display unit 30 and the notification unit 50 to notify the occurrence of the incoming call and An incoming call control function for establishing a voice communication link by causing the communication unit 10 to transmit a signal responding to the incoming call by a response operation of the user through the unit 40 is provided.

  In addition, the control unit 70 controls the communication unit 10 according to SIP in response to a user's call request through the operation unit 40, and a call control function for making a call to a telephone number designated by the user, And a communication control function for establishing a voice communication link. That is, the control unit 70 has control functions for realizing action determination, SIP message generation, SIP message analysis, data extraction from the SIP message, and SIP message transmission / reception in accordance with SIP.

  In addition, the control unit 70 controls the communication unit 10 to communicate with the server device on the Internet via the access point AP, and displays the data provided by the server device on the display unit 30 to allow the user to browse. It has functions.

  In addition, the control unit 70 monitors the communication state with the connected access point AP, performs control according to the type of the access point AP, and can perform the best communication as necessary. It has a communication control function to reconnect to.

  Next, the operation of the radio communication terminal apparatus having the above configuration will be described. In the following description, the operation related to the search for the access point AP will be mainly described. FIG. 4 is a flowchart for explaining the above operation, and is executed by the control unit 70. The control program shown in this flowchart is stored in the storage unit 60, and is realized by the control unit 70 executing control according to this program. This control is started when the wireless communication terminal device is turned on and is executed until the power is turned off.

  When the power is turned on, first, in step 4a, the control unit 70 controls the communication unit 10 to access points AP11, AP12, AP13, AP20 and AP30 in which connection data is already stored in the storage unit 60, unknown Attempt to receive a beacon signal transmitted from the access point AP. Then, the access point ID of the access point AP that has received the beacon signal is detected, the reception level of the beacon signal received from the access point AP is detected, and the process proceeds to step 4b.

  In step 4b, the control unit 70 preferentially selects an access point AP whose access point ID is stored as connection data in the storage unit 60 among the access points AP that have received the beacon signal in step 4a. Transition. Here, when a plurality of access points AP correspond, the access point AP having the highest reception level is selected based on the reception level detected in step 4a.

  Here, when only the access point AP whose access point ID is not stored in the storage unit 60 is detected in step 4a, the reception level detected in step 4a among the access point APs detected in step 4a. Based on the above, the access point AP with the highest reception level is selected. In the following description, the access point AP selected in step 4b is referred to as a connection access point AP.

  In step 4c, the control unit 70 controls the communication unit 10 to connect to the connection access point AP, starts communication via the connection access point AP, and proceeds to step 4d. When the connection access point AP is an access point AP whose access point ID is stored as connection data in the storage unit 60, communication is performed using necessary parameters by referring to the corresponding connection data and following the procedure. To start.

  In step 4d, the control unit 70 monitors the communication state of the communication unit 10, and determines whether or not it is in an idle state in which data reception from the connection access point AP and data transmission to the connection access point AP are not performed. . Here, when it is in the idle state, the process proceeds to step 4e, and when it is not in the idle state, the process proceeds to step 4d to continuously monitor the idle state.

  In step 4e, the control unit 70 controls the communication unit 10, receives a beacon signal periodically transmitted from the connection access point AP, detects the reception level of the received beacon signal, and proceeds to step 4f. .

  In step 4f, the control unit 70 determines whether the connection access point AP is an unstable access point AP or a stable access point AP based on the access point ID detected in step 4a and the connection data of the storage unit 60. To do. When the connection access point AP is an unstable access point AP, the process proceeds to step 4g. On the other hand, when the connection access point AP is a stable access point AP, the process proceeds to step 4j.

  The unstable access point AP is an access point AP whose connection setting method is set to “public” as connection data in the storage unit 60, while connection setting is set as connection data in the storage unit 60. An access point AP whose method is set to “manual setting” or “automatic setting”. When the access point ID detected in step 4a does not exist in the connection data of the storage unit 60, it is regarded as “public”.

  Here, the connection access point AP is determined based on the stable type and the non-stable type, but may be determined based on the difference in the authentication method as shown in FIG. That is, in the case of an access point AP that employs an authentication method compliant with IEEE (The Institute of Electrical and Electronics Engineers) 802.1X, the process proceeds to step 4g, while an access point AP that employs, for example, a shared key authentication method. In this case, the process proceeds to step 4j.

  In addition, when communication is started, the time during which communication was continued is measured for each access point AP, and the measured time and the average value are stored in the storage unit 60 as connection data. To do. In step 4f, the control unit 70 proceeds to step 4g when the stored value is equal to or smaller than a preset threshold value, that is, in the case of an access point AP that cannot perform stable communication, If it is larger than the threshold value, that is, in the case of an access point AP capable of stable communication, the process may move to step 4j.

  In step 4g, the control unit 70 determines whether or not the communication quality is equal to or lower than the threshold by determining whether or not the state in which the reception level detected in step 4e is equal to or lower than the threshold th1 continues for a predetermined number of samples. Determine. Here, when the communication quality is equal to or lower than the threshold value, the access point AP scan is performed by the scan method A in steps 4h and 4i. On the other hand, if the communication quality is not below the threshold, the process proceeds to step 4d.

  FIG. 5 shows an example of one sample as the predetermined number. In this example, since the reception level for one sample is equal to or less than the threshold th1 at time T1, the control unit 70 proceeds to step 4h. Although the case of one sample is illustrated here, in order to improve the accuracy of determination in step 4g, a plurality of samples are more desirable.

  In step 4h, the control unit 70 controls the communication unit 10 to receive a beacon signal periodically transmitted from the connected access point AP, and another access point AP transmits it during a period when the beacon signal is not transmitted. Detect a beacon signal. Moreover, the control part 70 detects the reception level of each received beacon signal, and transfers to step 4i.

  FIG. 5 illustrates a case where a beacon signal transmitted from the connected access point AP and a beacon signal transmitted from another access point AP are received at time T2. In this example, a plurality of samples of beacon signals are received for each access point AP, but one sample may be received.

  In step 4i, when the control unit 70 receives a beacon signal periodically transmitted from the connected access point AP and confirms that the reception level is equal to or lower than the threshold th2, reception of the beacon detected in step 4h and step 4i. Based on the level, the access point AP that provides the best communication quality is selected.

  Then, the control unit 70 controls the communication unit 10 to connect to the selected access point AP, starts communication through the access point AP, and proceeds to step 4d. Here, when it cannot be confirmed that the reception level is equal to or lower than the threshold th2, the process proceeds to step 4d without selecting the access point AP.

  The process in step 4i is shown at time T3 in FIG. In the above description, in step 4i, the control unit 70 receives the beacon signal periodically transmitted from the connection access point AP again, and selects the access point AP when the reception level is equal to or lower than the threshold th2. However, this procedure may be omitted. That is, when the process proceeds to step 4i, the access point AP may be selected based on the detection result of step 4h.

  In step 4j, the control unit 70 determines whether or not communication is not possible by determining whether or not the state in which the reception level detected in step 4e is equal to or less than the threshold th2 continues for a predetermined number of samples. judge. Here, when the communication is not possible, the access point AP scan is performed by the scan method B in steps 4k and 4l. On the other hand, if the communication quality is not below the threshold, the process proceeds to step 4d.

  FIG. 6 shows an example of one sample as the predetermined number. In this example, since the reception level for one sample is equal to or less than the threshold th2 at time T4, the control unit 70 proceeds to step 4k. Although the case of one sample is illustrated here, in order to improve the accuracy of determination in step 4j, a plurality of samples are more desirable. In step 4j, the reception quality may be determined based on whether or not predetermined data is obtained from the beacon signal actually received by the communication unit 10, instead of the determination based on the reception level as described above.

  In step 4k, the control unit 70 controls the communication unit 10 to receive a beacon signal periodically transmitted from the connected access point AP, and another access point AP transmits it during a period when the beacon signal is not transmitted. Detect a beacon signal. Moreover, the control part 70 detects the reception level of each received beacon signal, and transfers to step 4l.

  FIG. 6 illustrates a case where a beacon signal transmitted from the connected access point AP and a beacon signal transmitted from another access point AP are received at time T5. In this example, one sample beacon signal is received for each access point AP, but a plurality of samples may be received.

  In step 41, the control unit 70 determines whether or not communication with the connected access point AP is possible based on the reception level of the beacon detected in step 4k, and selects the connected access point AP when communication is possible. . If communication is not possible, an access point AP that provides the best communication quality is selected.

  Then, the control unit 70 controls the communication unit 10 to connect to the selected access point AP, starts communication through the access point AP, and proceeds to step 4d. The process in step 4l is shown at time T6 in FIG.

  As described above, in the wireless communication terminal device configured as described above, the operation of the connection access point AP is to operate in an environment where stable communication should be possible, such as operation in the coffee shop CA or the house HM illustrated in FIG. Detection is performed from the identification information and the connection data of the access points AP20 and AP30 stored in advance. In this case, when communication cannot be performed by the scanning method B, a beacon signal is received.

  Then, as in the operation at the hotel HT shown in FIG. 1, the operation of the environment where there is a possibility that the communication may not be stable, the identification information of the connection access point AP and the access points AP11 to AP13 stored in advance. In this case, the beacon signal is received and the access point AP suitable for the connection is detected by the scan method A before communication is disabled. When communication cannot be actually performed, connection is made to an access point AP suitable for communication based on the detected information of the access point AP.

  That is, in an environment where stable communication can be performed, the search for the peripheral access point AP is not performed. On the other hand, in the environment where the communication may not be stable, the search for the peripheral access point AP is actively performed. Therefore, according to the wireless communication terminal device configured as described above, it is possible to search for peripheral access points according to the communication environment, so that power consumed for searching for peripheral access points can be reduced and search for peripheral access points can be performed efficiently. Can do.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. Further, for example, a configuration in which some components are deleted from all the components shown in the embodiment is also conceivable. Furthermore, you may combine suitably the component described in different embodiment.

  As an example, for example, in the above-described embodiment, the search for the peripheral access point AP is not performed in an environment where stable communication can be performed, while the search for the peripheral access point AP is actively performed in an environment where communication may not be stable. In the environment where stable communication can be performed, the control unit 70 may control each unit to search for the peripheral access point AP. However, in this case, the search is performed less frequently than in an environment where communication may not be stable. Even with such control, it is possible to reduce power consumed for searching for peripheral access points and to efficiently search for peripheral access points.

  In step 4f, it may be determined whether the system is an open system. In the case of an open system, the process proceeds to step 4g. On the other hand, in the case of an open system, the process proceeds to step 4j.

  The open system is one of wireless LAN authentication methods. This system is an authentication system in which an authentication request is sent from a wireless communication terminal device to an access point AP without qualification information, and the access point AP accepts the requested authentication as it is. As an authentication method in the wireless LAN, in addition to the open system authentication method, there are a shared key authentication method and an IEEE 802.1X authentication method as shown in FIG.

  The shared key authentication method is a method of authenticating by confirming whether or not the same encryption key is shared between the access point AP and the wireless communication terminal device. The data transmitted by the access point AP is transmitted to the wireless communication terminal device side. It is determined whether or not the encryption key is shared by encrypting and transmitting it back to the access point AP again.

  The IEEE802.1X authentication method uses a user ID, password, or whether the wireless communication terminal device requesting connection is connectable to the network after the wireless LAN connection is completed (open system or shared key authentication is completed). Digital certificate authentication is performed.

As an example of an embodiment of the present invention, as shown in FIG. 1, a wireless communication terminal device is shown in a shape similar to a mobile phone, but a wireless device mounted on a PDA (Personal Digital Assistance) or a personal computer. It is also possible to apply to.
In addition, it goes without saying that the present invention can be similarly implemented even if various modifications are made without departing from the gist of the present invention.

The figure for demonstrating the environment where the radio | wireless communication terminal device concerning this invention is operate | moved. The circuit block diagram which shows the structure of one Embodiment of the radio | wireless communication terminal device concerning this invention. The figure which shows an example of the connection data memorize | stored in the memory | storage part of the radio | wireless communication terminal device shown in FIG. The flowchart for demonstrating the control action in connection with the access point search of the radio | wireless communication terminal device shown in FIG. 7 is a flowchart for explaining access point search by scan method A of the wireless communication terminal device shown in FIG. 1. 7 is a flowchart for explaining access point search by scan method B of the wireless communication terminal device shown in FIG. 1.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Antenna, 10 ... Communication part, 20 ... Sound processing part, 21 ... Speaker, 22 ... Microphone, 30 ... Display part, 40 ... Operation part, 50 ... Notification part, 60 ... Memory | storage part, 70 ... Control part, 100 ... Wireless communication terminal devices, AP11-13 ... access point, AP20 ... access point, AP30 ... access point, CA ... coffee shop, HM ... residence, HT ... hotel.

Claims (5)

In a wireless communication terminal device that performs wireless communication with an access point accommodated in a LAN and performs communication through the LAN,
A communication means for wirelessly communicating with the access point;
A determination unit that determines a type of an access point with which the communication unit performs wireless communication;
Search means for searching for an access point other than the access point with which the communication means is performing wireless communication at a frequency according to the type of the access point determined by the determination means;
A wireless communication terminal apparatus comprising: a control unit that controls the communication unit and connects to an access point based on a search result of the search unit. In a wireless communication terminal device that performs wireless communication with an access point accommodated in a LAN and performs communication through the LAN,
A communication means for wirelessly communicating with the access point;
Storage means for storing identification information of the access point;
Detecting means for detecting identification information of an access point with which the communication means is wirelessly communicating;
If the identification information detected by the detection means is not stored in the storage means, the communication means searches for an access point other than the access point with which the communication means is performing wireless communication at a preset first frequency, On the other hand, when the identification information detected by the detection means is stored in the storage means, the communication means other than the access point with which the communication means is wirelessly communicating at a second frequency lower than the first frequency. Search means for searching for access points;
A wireless communication terminal apparatus comprising: control means for controlling the communication means to connect to an access point based on a search result of the search means. In a wireless communication terminal device that performs wireless communication with an access point accommodated in a LAN and performs communication through the LAN,
A communication means for wirelessly communicating with the access point;
Detecting means for detecting an authentication method of an access point with which the communication means is wirelessly communicating;
When this detection means detects IEEE802.1X as an authentication method, the communication means searches for an access point other than the access point with which the communication means is wirelessly communicated at a first frequency set in advance. If the means does not detect IEEE802.1X as an authentication method, the communication means searches for an access point other than the access point with which the communication means is wirelessly communicating at a second frequency lower than the first frequency. Search means;
A wireless communication terminal apparatus comprising: control means for controlling the communication means to connect to an access point based on a search result of the search means. In a wireless communication terminal device that performs wireless communication with an access point accommodated in a LAN and performs communication through the LAN,
A communication means for wirelessly communicating with the access point;
Detecting means for detecting an authentication method of an access point with which the communication means is wirelessly communicating;
When the detection means detects an open system as an authentication method, the communication means searches for an access point other than the access point with which the communication means is wirelessly communicated at a preset first frequency, while the detection means Search means for searching for an access point other than the access point with which the communication means is wirelessly communicating at a second frequency lower than the first frequency when the open system is not detected as an authentication method When,
A wireless communication terminal apparatus comprising: a control unit that controls the communication unit and connects to an access point based on a search result of the search unit. In a wireless communication terminal device that performs wireless communication with an access point accommodated in a LAN and performs communication through the LAN,
A communication means for wirelessly communicating with the access point;
Time detection means for detecting the communication time by this communication means for each access point;
Storage means for storing the identification information and the communication time in association with each access point;
Detecting means for detecting identification information of an access point with which the communication means is wirelessly communicating;
If the communication time associated with the identification information detected by the detection means is less than or equal to a preset threshold value with reference to the information stored in the storage means, the communication means When a search is performed for an access point other than a wireless communication access point, and the communication time associated with the identification information detected by the detection unit is longer than a preset threshold, the first frequency Search means for searching for an access point other than the access point with which the communication means is wirelessly communicating at a second frequency lower than
A wireless communication terminal apparatus comprising: control means for controlling the communication means to connect to an access point based on a search result of the search means.

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