JP2008067183A - Radio communication terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To extend the service life of a battery, to reduce the cost of a terminal and to enhance maintainability by reducing a power consumption required for the scanning operation of an access point. <P>SOLUTION: When the scanning processing of the access point is repeatedly executed in a cell of a base station, the number of times of scanning operations Sc are counted and the coefficient value Si of scanning intervals is increased one by one whenever the frequencies increase by a fixed amount and the scanning intervals are gradually lengthened. In addition, when the coefficient value Si of the scanning intervals reaches a reference value, the reference value St of the scanning intervals is increased by ten times and even after a portable terminal leaves the cell, the reference value St of the scanning intervals is associated with a base station identification number and held in a scanning management table. Then, when the portable terminal MS1 enters the cell again to scan the access point, the scanning intervals are set based on the reference value St of the scanning intervals held in the scanning management table to execute the scanning processing. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a dual mode type wireless communication terminal provided with an interface for portable wireless communication and an interface for short-range communication.

  In recent years, a dual-mode wireless communication terminal has been proposed that has an interface for short-range communication such as a wireless local area network (LAN) in addition to an interface for portable wireless communication that performs mobile communication with a mobile communication network. Has been. According to this type of terminal, efficient communication can be performed by properly using two interfaces according to the place of communication and the purpose. For example, use a short-range communication interface for large-capacity data communication in urban areas where a short-range communication network is established, and use a portable wireless communication interface for telephone communication in rural areas. Thus, efficient data communication and telephone communication can be performed.

  By the way, when using a near field communication network in this type of wireless communication terminal, it is necessary to scan and capture an access point to the near field communication network. If this access point search is not performed efficiently, power is wasted, which leads to a reduction in battery life, which is very undesirable.

Therefore, conventionally, several methods have been proposed in which it is determined in advance whether or not near field communication is possible based on the position of the wireless communication terminal and an access point is searched when possible. For example, the position of a wireless communication terminal is detected based on the base station ID of a mobile communication base station to determine whether or not short-range communication is possible, using GPS (Global Positioning System) There are those that detect a position and determine whether or not near field communication is possible, and those that combine these (for example, see Patent Document 1).
JP 2004-350108 A

  However, the above-described conventionally proposed methods have the following problems to be solved. That is, first, in the case of detecting the position of a wireless communication terminal based on the base station ID of a mobile communication base station, the base station has a remarkably wide service area compared to a short-range communication network such as a wireless LAN. It is difficult in terms of accuracy to determine whether short-range communication is possible using only the position information detected based on the station ID. For this reason, an access point is scanned even in a place where short-range communication is actually impossible, and wasteful power is consumed accordingly. Next, the method of detecting the position of the wireless communication terminal using the GPS can detect the position with high accuracy, but in addition to increasing the cost of the terminal because it is necessary to add a GPS receiver to the wireless communication terminal. The increase in power consumption by the GPS receiver leads to a shortened battery life.

  Furthermore, conventionally, a database representing the position of an access point is generally constructed in advance, and the access point can be captured based on the terminal position detection results by the various position detection means and the stored data in the database. It is determined whether or not. For this reason, it is necessary to reconstruct the database every time an access point is added or the installation position is changed, which requires a lot of maintenance.

  The present invention has been made paying attention to the above circumstances, and its purpose is to determine whether or not access to an access point for near field communication is possible without preparing a highly accurate position detection function or database. An object of the present invention is to provide a wireless communication terminal that can efficiently determine, thereby reducing power consumption during standby, extending battery life, and reducing the cost of the terminal and improving maintainability.

  In order to achieve the above object, the present invention provides a first communication module that performs wireless communication with a first base station that forms a first communication area, and the first communication module in the first communication area. A second communication module that performs wireless communication with a second base station that forms a second communication area that is smaller than the first communication area, and the first and second communication modules that perform the first and second communication modules. And a control module that controls a wireless communication operation with the base station. The control module allows the control module to control the first communication unit while staying in the first communication area formed by the first base station. It is periodically detected in the first period whether wireless communication with the second base station by the two communication modules is possible, and information indicating the detection result is stored in the staying state. Corresponding to the identification information of the first base station And stores it in the memory. Then, based on the information representing the detection result stored in the memory, it is determined whether or not a state where wireless communication with the second base station is impossible has reached a preset threshold value. When it is determined that the detection period has been reached, the detection period is changed from the first period to a second period longer than the first period.

  Therefore, according to the present invention, when the state in which wireless communication with the second base station cannot be performed reaches a preset threshold value while staying in the first communication area formed by the first base station. The detection period of the second base station is changed to a longer period than before. That is, in a situation where it is determined that the possibility of detecting the second base station is low, the detection cycle of the second base station is extended and the detection frequency is reduced. For this reason, as compared with the case where the detection process of the second base station is always executed in a short cycle, it is possible to reduce wasteful power consumption during standby and thereby extend the battery life. In addition, since the presence or absence of the second base station is managed in association with the first base station, it is necessary to provide a precise position detecting means such as a GPS receiver and a database that records the position of the second base station. Therefore, there is no concern of increasing the cost of the terminal and complicating the maintainability.

  In other words, according to the present invention, it is possible to efficiently determine whether or not access to an access point for near field communication is possible without preparing a highly accurate position detection function or database, and thereby the battery of the terminal can be determined. It is possible to provide a wireless communication terminal capable of extending the lifetime, reducing the price of the terminal, and improving maintainability.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic diagram showing an embodiment of a mobile communication system in which a wireless communication terminal according to the present invention is used. This mobile communication system is a combination of a mobile communication network and a wireless local area network (LAN) as a short-range communication network. The mobile communication network includes a plurality of portable base stations (in the figure, seven base stations BS1 to BS7 are illustrated) distributed in the service area. These portable base stations BS1 to BS7 respectively form portable communication areas (hereinafter referred to as cells) E1 to E7. These cells E1 to E7 are generally set to a diameter of, for example, several kilometers. On the other hand, the wireless LAN includes a plurality of access points (three access points AP1 to AP3 are illustrated in the figure). Access points AP1 to AP3 form wireless areas Z1 to Z3, respectively. These radio areas Z1 to Z3 are generally set to a diameter of one hundred meters to several hundred meters.

  The mobile terminal MS1 as a wireless communication terminal is a so-called dual mode type mobile terminal having a function of performing wireless communication with a mobile communication network and a function of performing wireless communication with a wireless LAN. The portable terminal MS1 selects any one of the portable base stations BS1 to BS7 of the portable communication network and the access points AP1 to AP3 of the wireless LAN, and the location registration server (FIG. (Register not shown). The selection of the portable base stations BS1 to BS7 and the access points AP1 to AP3 is performed based on preset priority or communication quality.

  The location registration server is commonly used between the mobile communication network and the wireless LAN. Then, the identification information of the portable terminal MS1 notified by the location registration from the portable terminal MS1 is stored in association with the identification information of the selected base station or access point. The mobile communication system includes a control station (not shown) that manages the mobile communication network and the wireless LAN in an integrated manner. When an incoming call to the mobile terminal MS1 occurs, the control station refers to the identification information stored in the location registration server, and passes through either the base station of the corresponding mobile communication network or the access point of the wireless LAN. An incoming call notification is transmitted to MS1. The mobile terminal MS1 performs standby processing such as incoming call on the selected network and receives the incoming call notification.

  By the way, the portable terminal MS1 is configured as follows. FIG. 2 is a block diagram showing the configuration. That is, the mobile terminal MS1 is a dual mode type terminal as described above, and includes a mobile communication module, a wireless LAN module, and a control module for controlling them.

  The module for portable communication includes a portable antenna 11, a portable radio unit 12, a portable signal processing unit 13, and a portable control unit 14. The portable radio unit 12 has a function of receiving radio signals transmitted from the portable base stations BS1 to BS7 via the portable antenna 11, and a portable radio transmission signal from the portable antenna 11 to the base stations BS1 to BS7. It has a function to transmit to. The portable signal processing unit 13 performs a demodulation process and an error correction / detection process on the reception signal output from the portable wireless unit 12 and outputs reception data, and transmission data output from the portable control unit 14 Have a function of adaptively adding an error detection code, error correction coding, and adaptive modulation processing to a radio signal. Furthermore, the portable signal processing unit 13 has a function of performing interleaving / de-interleaving processing on transmission / reception data in order to improve transmission path error tolerance.

  The portable control unit 14 has a function of controlling the portable signal processing unit 13. For example, the transmission system transfers transmission data to the portable signal processing unit 13, requests error detection and error correction processing for transmission data, and requests modulation processing. For the reception system, reception signal demodulation processing and error correction・ A request for detection processing and acquisition processing of received data are performed. The portable control unit 14 also has a function of performing detection processing and synchronization processing of neighboring base stations by transmitting and receiving control signals to and from the base stations BS1 to BS7 under the control of the main control unit 15 described later. .

  On the other hand, the wireless LAN module includes a wireless LAN antenna 21, a wireless LAN wireless unit 22, a wireless LAN signal processing unit 23, and a wireless LAN control unit 24. The wireless LAN wireless unit 22 has a function of performing wireless LAN signal transmission / reception processing via the wireless LAN antenna 21 with the wireless LAN access points AP1 to AP3. The wireless LAN signal processing unit 23 performs a function of performing demodulation processing, error correction processing, and error detection processing on the reception signal output from the wireless LAN wireless unit 22, and transmission data output from the wireless LAN control unit 24. It has a function of performing error detection / correction coding and additional processing.

  The wireless LAN control unit 24 has a function of controlling the wireless LAN signal processing unit 23. For example, it requests error correction coding and modulation processing for transmission data, and requests demodulation processing and error correction decoding processing for a received signal. The wireless LAN control unit 24 also has a function of performing scanning and synchronization establishment processing of the access points AP1 to AP3 by transmitting and receiving control signals to and from the access points AP1 to AP7 under the control of the main control unit 15. Have.

  The control module controls the entire mobile terminal such as the mobile communication module and the wireless LAN communication module, and includes a main control unit 15, a user interface unit, and a storage unit 20. The user interface unit includes a speaker 16 and a microphone 17, an input device 18 including a keypad, and a display device 19 such as a liquid crystal display (LCD) or a light emitting diode.

  The storage unit 20 uses a NAND flash memory or a hard disk as a storage medium. In addition to an area for storing various application programs, a telephone book, transmission / reception history, contents, etc., the storage unit 20 is necessary for implementing the present invention. A scan management table storage area 201 is provided. The scan management information storage area 201 stores scan management information used for scanning a wireless LAN access point.

  For example, as shown in FIG. 6, the scan management table is associated with the identification number (BSID) of the captured base station, and the stay time of the own terminal in the cell formed by the base station (zone time (BSst )) Is memorized. Further, whether or not the access point has been captured in the cell and if it has been captured, its identification number (SSID), the number of scans for the access point (Sc), and the coefficient (Si) of the scan interval (interval) The reference value (St) of the scan interval is stored in association with the identification number (BSID) of the base station.

  The main control unit 15 includes a central processing unit (CPU) and a digital signal processing unit (DSP) that performs transmission / reception data encoding and decoding processing. Then, transmission / reception data encoding and decoding processing functions, standby control functions for mobile communication networks or wireless LANs, functions for controlling mobile communication network and wireless LAN system selection and handover between systems, speaker 16 and microphone 17 Has a function of performing input / output control of a call signal and control of output of music content using the computer, a function of controlling reception of input data and display of display data by the input device 18 and the display device 19, and the like.

Further, in addition to the various control functions described above, the main control unit 15 has a scan execution control function 151 for an access point and a scan interval control function 152 as control functions necessary for carrying out the present invention.
The scan execution control function 151 executes scan control for the access point according to the scan interval stored in the scan management table storage area 201 of the storage unit 20. The scan interval is determined by a product of the scan interval coefficient Si and the scan interval reference value St.

  The scan interval control function 152 performs a process of increasing the scan interval coefficient Si in a stepwise manner in accordance with the number of scans Sc stored in the scan management table storage area 201 of the storage unit 20 and the scan interval coefficient Si in advance. Whenever the set upper limit value is reached, the coefficient value Si of the scan interval is initialized, and instead, the scan interval reference value St is increased, and when the base station access point can be captured, the scan interval reference value St is set. It has a function of performing initialization processing and processing for delaying the start of scanning for an access point when the in-zone time in the cell of the same base station is less than or equal to a preset threshold value.

  Next, an access point scanning operation by the mobile terminal MS1 configured as described above will be described. 4 and 5 are flowcharts showing the control procedure and control contents. In this embodiment, a case will be described as an example where priority is set higher for access points as priority when selecting base stations and access points.

  When the mobile terminal MS1 is turned on, the main control unit 15 first executes a search process (base station search) for the portable base stations BS1 to BS7 in step S41. The search for the portable base stations BS1 to BS7 is performed by trying to receive a pilot signal broadcast by the portable base stations BS1 to BS7. The main control unit 15 determines in step S42 whether or not a base station capable of wireless communication has been detected by searching for the base station. As a result of the determination, if a base station capable of wireless communication cannot be detected, the process proceeds to step S45 where the scan interval coefficient Si and the reference value St are set to initial values (= 0) and the number of scans Sc is set to “ Reset to 0 ”.

  On the other hand, when the base station capable of wireless communication can be detected, the main control unit 15 starts to measure the stay time in the cell of the base station, and the stay time of the scan management table stored in the storage unit 20 BSst is updated to the above measured value. Further, the main control unit 15 proceeds to step S43, and based on the scan management information stored in the storage unit 20, whether or not the detected base station is the first detected base station, that is, the scan management table. It is determined whether or not it is a registered base station. As a result of the determination, if the detected base station is the first detected base station, the process proceeds to step S45, and the scan interval coefficient Si and the reference value St are set to initial values (= 0). At the same time, the scan count Sc is reset to “0”.

  On the other hand, if the detected base station is a base station registered in the scan management table, the main control unit 15 sets the scan interval coefficient Si to an initial value (= 0) in step S44, In addition, the number of scans Sc is reset to “0”. That is, when the detected base station has already been registered in the scan management table, only the scan interval coefficient Si is set to the initial value (= 0), and the scan interval reference value St is stored in the scan management information. Maintain the value.

  Next, the main control unit 15 determines in step S46 whether the stay time in the cell of the base station stored in the scan management table (in-service time BSst) is greater than or less than a preset reference value. As a result of this determination, if the staying time has reached the reference value, the process proceeds to step S47, and the access point scanning process is executed.

  On the other hand, while the stay time has not reached the reference value, the process proceeds to step S48 where the scan process stop timer is started. Then, after the scan process stop timer expires, the process proceeds to step S47 to execute the access pointer scan process. That is, even when the mobile terminal MS1 enters the cell, the start timing of the scanning process is delayed while the staying time does not reach the reference time.

  Controlling in this way provides the following effects. That is, the communication areas Z1 to Z3 of the access points AP1 to AP3 are smaller than the cells E1 to E7 of the portable base stations BS1 to BS7. For this reason, when the portable terminal MS1 stays in the cells E1 to E7 of the portable base stations BS1 to BS7 only for a short period, the probability that the communication areas Z1 to Z3 of the access points AP1 to AP3 can be detected is low. Even if it can be detected, the time during which wireless communication can be substantially performed is extremely short. In such a case, there is a high probability that the access point scan process is wasted. Therefore, as described above, while the stay time of the mobile terminal MS1 has not reached the reference time, the access point scan process is not performed. In this way, useless scan processing can be prevented and an increase in power consumption can be suppressed accordingly.

  When one scan process is executed, the main control unit 15 determines whether or not an access point has been detected in step S49. If the access point cannot be detected as a result of this determination, the process moves to step S53, and 1 is added to the scan count Sc in the scan management table. Subsequently, in step S54 shown in FIG. 5, the main control unit 15 determines whether or not the number of scans Sc after the addition is larger than a preset reference value. If the number of scans has not reached the reference value, the process proceeds to step S58 to determine whether or not the own terminal is in the base station cell. If the result of this determination is that the terminal itself has not entered the cell of the base station, the process returns to step S41 in FIG. 4 and the base station search is executed again.

  On the other hand, when the own terminal is already in the cell of the base station, the main control unit 15 determines whether or not synchronization with the base station is established in step S59. If synchronization is established, after setting a scan interval in the scan processing timer in step S61, the timer is started. On the other hand, if the synchronization with the base station has not been established yet, after executing the synchronization establishment procedure with the base station in step S60, the process proceeds to step S61 to set the scan interval in the scan processing timer. Set and activate. When the scan processing timer is started, the main control unit 15 monitors whether or not the scan processing timer has expired in step S62, that is, whether or not the set scan interval has elapsed. When the scan interval elapses, the process returns to step S47 in FIG. 4 and the scan process is executed again.

  The scan interval is read from the scan management table stored in the storage unit 20 by reading the scan interval coefficient Si and the reference value St corresponding to the base station of the cell in which the terminal is currently located. It is set as a multiplication value of the issued scan interval coefficient Si and the reference value St.

  Thereafter, similarly, until an access point capable of wireless communication is detected, the access point scan process is repeatedly executed at the scan interval set in the scan process timer. Each time the scan process is executed once, the scan count Sc in the scan management table is incremented by one.

  Further, it is assumed that the number of scans Sc exceeds the reference value as a result of repeatedly executing the scan process. Then, the main control unit 15 proceeds from step S54 to step S55, and adds 1 to the coefficient value Si of the scan interval. Thereafter, similarly, every time the number of scans Sc increases by the reference value, the coefficient value Si of the scan interval is incremented by one. Therefore, every time the number of scans Sc increases by the reference value, the scan interval becomes longer by the coefficient value Si.

  Further, the main control unit 15 determines whether or not the coefficient value Si of the scan interval has exceeded a preset reference value during the repeated execution of the scan process in step S56. If the coefficient value Si of the scan interval exceeds the reference value as a result of this determination, the process proceeds from step S56 to step S57 to initialize the scan interval coefficient value Si, and instead the scan interval reference value St is set in advance. Increase by a certain amount.

  On the other hand, it is assumed that an access point is detected during the repeated execution of the scan process. In this case, the main control unit 15 proceeds from step S49 to step S50, and executes a connection procedure with the detected access point. In this connection procedure, in addition to the synchronization establishment process between the mobile terminal MS1 and the access point, association and authentication procedures are performed. Then, in step S51, it is determined whether or not the connection is successful. If the connection to the access point fails as a result of this determination, the process moves to step S52. Then, it is determined whether there is another detected access point, and if there is, a connection request is made to this access point. If there is no other access point that has been detected as a result of this determination, or there is no access point that has not made a connection request even if there is no access point, the process proceeds to step S53, and 1 is added to the number of scans Sc.

  On the other hand, it is assumed that connection to at least one of the detected access points has been established. In this case, the main control unit 15 proceeds to step S63 and resets the coefficient value Si and the reference value St of the scan interval of the scan management table stored in the storage unit 20 to the initial values and succeeds in the connection. The access point identification number SSID is stored in the scan management table. Then, in step S64, wireless communication is performed via a communication link with the access point while monitoring whether or not the terminal is out of the communication area of the access point in step S65. Then, when the own terminal is outside the communication area of the access point, the scanning process in step S47 is executed.

Next, the scanning operation by the portable terminal MS1 described above will be described more specifically.
Here, as shown in FIG. 3, the mobile terminal MS1 first turns on the power at the position P31 in the cell E2, then moves to the position P32 in the cell E1, and then communicates with the access point AP1 in the cell E1. The wireless communication is performed by moving to the position P33 in the area Z1. Next, after leaving the communication area Z1 of the access point AP1 and moving to the position P34 in the cell E2, the communication is further performed by moving to the position P35 in the communication area Z2 of the access point AP2 in the cell E2. . The case where the user exits from the communication area Z2 of the access point AP2 and returns to the initial position P31 will be described as an example.

(1) At position P31
When the mobile terminal MS1 is turned on at the position P31, the mobile terminal MS1 first performs a base station search (step S41). When the base station BS2 is detected by this search, location registration is performed with respect to a location registration server (not shown) via the base station BS2. In addition, it is determined whether or not the base station BS2 has been registered in the scan management table (step S43). If not registered, the identification number of the base station BS2 is newly registered in the scan management table. The scan interval coefficient Si and the reference value St are set to initial values (= 0), and the scan count Sc is reset to “0” (step S45). FIG. 6 (1) shows the stored contents of the scan management table at this time.

  The mobile terminal MS1 is set with a mode in which the access point is used preferentially as described above. For this reason, the mobile terminal MS1 executes an access point scan process. However, no access point can be detected at position P31 as shown in FIG. For this reason, the mobile terminal MS1 repeatedly executes the access point scanning process. However, the scan processing execution interval (scan interval) at this time is set to 1, which is a product of the scan interval coefficient value Si = 1 and the reference value St = 1, as shown in FIG. The Therefore, the access point scanning process is repeatedly executed in a relatively short period.

  Then, when the number of executions Sc of the scanning process reaches 10, for example, as shown in (2) of FIG. 6, the coefficient value Si of the scan interval is incremented by 1 and becomes Si = 2 (step S55). Thereafter, similarly, every time the scan processing execution count Sc increases by 10, the coefficient value Si of the scan interval is incremented by one. When the coefficient value Si of the scan interval becomes Si = 7, for example, the coefficient value Si of the scan interval is initialized to Si = 1 as shown in (3) of FIG. Is set to St = 10, that is, 10 times. That is, the scan interval Si × St is controlled to increase stepwise as the number of scans increases. Therefore, in a place where the access point cannot be detected or is difficult to detect, the scan interval Si × St is increased stepwise, thereby reducing the power consumption by the scan processing.

  Before the access point scanning process is started, the mobile terminal MS1 determines whether or not the stay time BSst of its own terminal in the cell E2 is greater than or equal to a reference value, and until the reference value is reached. The scan process is postponed (step S48). Therefore, for example, when the mobile terminal MS1 moves at a high speed and leaves the cell E2 in a short time, the scan process is controlled so as not to be executed, thereby suppressing wasteful power consumption. .

(2) In P32
When the mobile terminal MS1 moves from the cell E2 to the position P32 in E1, the mobile terminal MS1 captures the base station BS1 instead of the base station BS2, and performs location registration with the server via the base station BS1. If the base station BS1 is the first base station captured, the identification number of the base station BS1 is additionally registered in the scan management table, and the scan interval coefficient Si and the reference value St are initial values (= 0). And the number of scans Sc is reset to “0”. FIG. 7 (1) shows the stored contents of the scan management table at this time. At this time, the scan management table holds the management information immediately before the mobile terminal MS1 leaves the cell E2 of the base station BS2.

  Even when the mobile terminal MS1 moves to the position P32 in the cell E1, the access point after the stay time BSst of the terminal in the cell E1 exceeds the reference value, as in the case of the position P31 in the cell E2. The scanning process is started. Then, the scanning process is repeatedly executed until an access point is detected. At this time, the coefficient value Si of the scan interval increases by 1 every time the number of scans Sc reaches 10 as in the case of the position P31 described above ((2) in FIG. 7). The value St = 1 is set to 10 times every time the scan interval coefficient value Si becomes, for example, Si = 7. Accordingly, the scan interval Si × St becomes longer stepwise as the number of scans Sc increases.

(3) At position P33
Assume that the mobile terminal MS1 moves in the cell E1 and enters the position P33 in the communication area Z1 of the access point AP1. In the mobile terminal MS1, when the access point AP1 is detected by the scanning process (step S49) and further connected to the access point AP1 (step S51), the location registration server is connected via the detected access point AP1. Location registration is performed. In addition, the identification number of the detected access point AP1 is registered in the scan management table in association with the identification number of the base station BS1, and the coefficient value Si and the reference value St of the scan interval stored in the scan management table are respectively stored. The initial values Si = 1 and St = 1 are reset (step S63). FIG. 7 (3) shows the state of the scan management table at this time. In this state, wireless communication is thereafter possible between the mobile terminal MS1 and the access point AP1.

(4) In the middle of moving from position P33 to P34
Assume that the wireless communication is terminated and the mobile terminal MS1 goes out of the communication area Z1 of the access point AP1. In this case, since the mobile terminal MS1 disconnects the wireless link with the access point AP1, the access point scanning process is started again. Then, the scanning process is repeatedly executed until an access point is detected. For this reason, the number of scans Sc increases, and the coefficient value Si of the scan interval is also counted up as the number of scans Sc increases. FIG. 8 shows an example of the contents stored in the scan management table immediately before the portable terminal MS1 goes out of the cell E1.

(5) At position P34
Assume that the mobile terminal MS1 moves from the cell E1 of the base station BS1 to the cell E2 of the adjacent base station BS2. In this case, since the mobile terminal MS1 is out of the range of the base station BS1 (step S58), a search for the base station is performed (step S41). When the base station BS2 is captured instead of the base station BS1 by this search, location registration is performed with respect to the location registration server via the captured base station BS2.

  Incidentally, in this case, the base station BS2 is not the first base station captured. Therefore, in the scan management table, the number of scans Sc is reset to “0”, and the coefficient value Si of the scan interval is set to the initial value (= 0), but the reference value St of the scan interval is set to the initial value. Instead, the value stored in the scan management table is maintained as it is. FIG. 9 (1) shows the stored contents of the scan management table at this time.

  Then, in the mobile terminal MS1, as in the case where the mobile terminal MS1 moves to the position P32 in the cell E1, it is determined that the stay time BSst of the terminal in the cell E2 exceeds the reference value (step S46), and then the access point The scanning process is started. Then, the scanning process is repeatedly executed until an access point is detected. However, the initial value of the scan interval in this case is set to a multiplication value of the scan interval coefficient value Si = 1 and the reference value St = 10 stored in the scan management table.

  That is, the scan process is executed at an interval in which the scan interval reference value St = 10 stored when the user stayed in the cell E2 before is reflected as an offset value. For this reason, when the cell E2 that has not been detected in the past has re-entered the cell E2, the scan process is started at a scan interval that is set longer from the beginning. Therefore, power consumption in the mobile terminal MS1 is suppressed.

(6) At position P35
Assume that the mobile terminal MS1 moves in the cell E2 and enters the position P35 in the communication area Z2 of the access point AP2. In the mobile terminal MS1, when the access point AP2 is detected by the scanning process (step S49) and further connected to the access point AP2 (step S51), the location registration server is connected via the detected access point AP2. Location registration is performed. In addition, the identification number of the detected access point AP2 is registered in the scan management table in association with the identification number of the base station BS2, and the coefficient value Si and the reference value St of the scan interval stored in the scan management table are respectively stored. The initial values Si = 1 and St = 1 are reset (step S63). FIG. 10 shows the state of the scan management table at this time. In this state, wireless communication is possible between the mobile terminal MS1 and the access point AP2.

(7) At position P31
Assume that the wireless communication is finished and the mobile terminal MS1 goes out of the communication area Z2 of the access point AP2. In this case, since the mobile terminal MS1 disconnects the wireless link with the access point AP2, the access point scanning process is started again. Thereafter, the scanning process is repeated until an access point is detected. For this reason, the number of scans Sc increases, and the coefficient value Si of the scan interval is also counted up as the number of scans Sc increases. FIG. 11 shows an example of the stored contents of the scan management table when the mobile terminal MS1 is present at the position P31 in the cell E2.

  As described above, in this embodiment, when the scan process for detecting the access points AP1 to AP3 is repeatedly performed in the communication areas E1 to E7 of the base stations BS1 to BS7, the number of scans Sc is counted. Each time the number of times increases by the reference value, the scan interval coefficient value Si is increased by 1, thereby controlling the scan interval to be increased stepwise. For this reason, it becomes possible to reduce the power consumption at the time of standby in a place where the access point cannot be detected or is difficult to detect, thereby extending the battery life.

  Further, when the coefficient value Si of the scan interval reaches the reference value, the scan interval reference value St is increased by 10 times, and the base value St is set after the mobile terminal MS1 leaves the cell. It is stored in the scan management table in association with the identification number. When the mobile terminal MS1 re-enters the cell and starts scanning the access point, the scan interval is set based on the scan interval reference value St held in the scan management table, and scan processing is performed. Is executed repeatedly. For this reason, the access point scan process is performed at intervals reflecting the past scan history in the same cell, and as a result, the power consumption in the cell where the access point could not be found in the past was reduced, thereby Battery life can be extended.

  Furthermore, before the access point scanning process is started, it is determined whether or not the stay time BSst of the own terminal in the same cell is equal to or greater than the reference value, and the scanning process is postponed until the reference value is reached. I have to. Therefore, for example, when the mobile terminal MS1 moves at a high speed and moves out of the cell in a short time, it is possible to prevent the scan process from being executed, thereby performing a useless scan process. In this way, power consumption can be reduced.

  The present invention is not limited to the above embodiment. For example, in the embodiment, the scanning process is postponed until the stay time BSst of the terminal in the same cell reaches the reference value. However, instead of postponing, the scanning process may be prohibited.

  In the above embodiment, BSst is the accumulated value of the staying time in the same cell. However, BSst is reset to 0 every time a cell is selected or reselected, so that the terminal stays in the same cell. The scanning process may be postponed until the time BSst reaches the reference value.

  Further, it is determined whether the mobile terminal is operating in the battery drive mode or the commercial power supply drive mode, and in the case of the battery drive mode, the variable control of the scan interval described in the above embodiment is executed. In the commercial power supply drive mode, the scan interval may not be varied and the fixed value may always be fixed. In this way, it is possible to scan an access point at a high frequency without considering power consumption.

  Furthermore, although the case where the wireless LAN is applied as the short-range communication system has been described as an example in the above-described embodiment, other short-range communication systems such as Bluetooth (registered trademark) and the Ultra Wide band system may be applied. In addition, the type of mobile communication system, the type and configuration of the wireless communication terminal, the control procedure for the scan interval, the control content, and the like can be variously modified and implemented without departing from the gist of the present invention.

  In short, 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. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

It is a schematic block diagram of the mobile communication system concerning one Embodiment of this invention. It is a block diagram which shows the structure of the portable terminal which is one Embodiment of the radio | wireless communication terminal concerning this invention. It is a figure which shows an example of the movement path | route of the portable terminal shown in FIG. It is a flowchart which shows the first half part of the control procedure and control content by the portable terminal shown in FIG. It is a flowchart which shows the latter half part of the control procedure and control content by the portable terminal shown in FIG. It is a figure which shows the 1st example of the control data managed with the portable terminal shown in FIG. It is a figure which shows the 2nd example of the control data managed with the portable terminal shown in FIG. It is a figure which shows the 3rd example of the control data managed with the portable terminal shown in FIG. It is a figure which shows the 4th example of the control data managed with the portable terminal shown in FIG. It is a figure which shows the 5th example of the control data managed with the portable terminal shown in FIG. It is a figure which shows the 6th example of the control data managed with the portable terminal shown in FIG.

Explanation of symbols

  BS1 to BS7 ... base stations for mobile communication, E1 to E7 ... mobile communication areas (cells), AP1 to AP3 ... wireless LAN access points, Z1 to Z3 ... access point communication areas, MS1 ... mobile terminals, 11 ... portable Antenna, 12 ... Portable wireless unit, 13 ... Portable signal processing unit, 14 ... Portable control unit, 15 ... Main control unit, 16 ... Speaker, 17 ... Microphone, 18 ... Input device, 19 ... Display device, 20 ... Storage unit, DESCRIPTION OF SYMBOLS 21 ... Wireless LAN antenna, 22 ... Wireless LAN radio | wireless part, 23 ... Wireless LAN signal processing part, 24 ... Wireless LAN control part, P31-P35 ... The position of a portable terminal.

Claims (5)

A first communication module that performs wireless communication with a first base station that forms a first communication area;
A second communication module that performs wireless communication with a second base station that forms a second communication area smaller than the first communication area in the first communication area;
A control module for controlling a wireless communication operation between the first and second base stations by the first and second communication modules;
The control module is
Whether or not wireless communication with the second base station by the second communication module is possible or not while staying in the first communication area formed by the first base station. Detection means for periodically detecting in one cycle;
First storage control means for storing information representing a detection result by the detection means in a memory in association with identification information of the first base station that is staying;
Based on the information representing the detection result stored in the memory, it is determined whether or not wireless communication with the second base station has reached a preset threshold, 1. A wireless communication terminal comprising: a first detection control unit configured to change a detection cycle by the detection unit from the first cycle to a second cycle longer than the first cycle when it is determined that the detection unit has performed. The control module is
A second detection control means for returning the detection period by the detection means to the first period when it is determined by the detection means that wireless communication with the second base station is possible; The wireless communication terminal according to claim 1, further comprising: The control module is
Second storage control means for storing, in the memory, information indicating the second period changed by the first detection control means in association with identification information of the first base station;
When entering the first communication area formed by the first base station, it is determined whether or not the identification information of the first base station is stored in the memory. 2. The apparatus according to claim 1, further comprising: a third detection control unit that sets a detection cycle by the detection unit to a second cycle based on information representing the second cycle stored in the first cycle. Wireless communication terminal. The control module is
Means for timing the stay time during stay in the first communication area formed by the first base station;
The time spent staying is compared with a predetermined reference time, and when the staying time is shorter than the reference time, the detection period by the detection means is changed from the first period to a third period longer than that. The wireless communication terminal according to claim 1, further comprising fourth detection control means that changes or delays a start timing of detection processing by the detection means. The control module is
Means for determining whether it is operating in a battery drive mode or a commercial power supply drive mode;
2. The wireless communication according to claim 1, further comprising: a unit configured to fix a detection cycle of the detection unit to the first cycle when it is determined that the device is operating in a commercial power supply drive mode. Terminal.

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