JP2011254542A - Mobile communication terminal, and position registration method and computer program thereof - Google Patents

Abstract

Location registration requests transmitted simultaneously by a large number of mobile communication terminals located in the vicinity are distributed to a plurality of radio base stations more preferably than in the past.
A mobile phone terminal 2 performs the following processing when location registration is necessary. Receives radio waves from a radio base station (BS) 31. One of the radio base stations 31 that is the source of the received radio wave is selected at random. Then, a request for location registration of the mobile phone terminal 2 itself is transmitted to the selected radio base station 31.
[Selection] Figure 1

Description

  The present invention relates to a mobile communication terminal in a wireless communication system, a location information registration method in the mobile communication terminal, and the like.

  In areas where a large number of people are crowded, such as stations or busy streets, many mobile communication terminals (mobile devices, mobile stations) used in wireless communication systems such as mobile phone systems are used at the same time. In such an area, communication traffic is constantly higher than in a quiet area, and a large load is likely to be applied to the radio base station. A mobile communication terminal may not be able to communicate when a load on a nearby radio base station is large.

  In addition, in a facility such as a concert hall immediately after the event ends, or at an airport arrival gate immediately after an airplane arrives, a large number of mobile communication terminals are simultaneously turned on. Then, communication traffic increases rapidly, and the mobile communication terminal may not be able to communicate.

  In order to solve these problems, measures have been taken to increase the number of radio base stations in areas where a large number of people are crowded or areas where a large number of mobile communication terminals are likely to turn on rapidly. Yes.

  However, this requires a large amount of investment and a large amount of expenses for subsequent operations and maintenance. From the viewpoint of protecting the natural environment, it is desirable to save energy by paying attention not to increase the number of radio base stations.

  In addition, in a congested area such as the city center, it may be difficult to secure a space for adding a radio base station.

  Therefore, it is desired to make the communication service comfortable without increasing the number of radio base stations. As one of methods for responding to this, it is possible to prevent a large number of mobile communication terminals from concentrating requests for registration of location information (location registration) to the same radio base station at one time, that is, request for location registration. Can be distributed to a large number of radio base stations.

Patent Document 1 describes a method for causing a mobile communication terminal to select a radio base station. According to this method, the mobile station (mobile communication terminal) receives broadcast information from the broadcast channel from each radio base station, and selects a radio base station with the largest number of free channels based on the broadcast information.
JP-A-4-213234

  However, in the conventional method as described in Patent Document 1, when a large number of mobile communication terminals request location registration all at once, such as immediately after the end of an event or arrival of an airplane, location registration is performed. May not be successfully distributed to the radio base stations.

  The present invention has been made in view of such problems, and it is an object of the present invention to suitably distribute location registration requests transmitted simultaneously by a number of mobile communication terminals located in the vicinity to radio base stations. .

  A mobile communication terminal according to the present invention is a mobile communication terminal that performs communication by radio, and includes a received radio wave intensity measuring unit that measures the intensity of a received radio wave that is a radio wave received from a radio base station, and a position of the mobile communication terminal Radio base station selection means for selecting to which radio base station a registration request is transmitted; and location registration request means for transmitting the request to the radio base station selected by the radio base station selection means; The radio base station selection means selects the radio base station related to the received radio wave having the highest intensity measured by the received radio wave intensity measurement means for the first time when the request is newly transmitted. If the location registration related to the request transmitted to any one of the radio base stations fails, the radio related to other received radio waves that is less than the intensity of the received radio wave related to the radio base station. Chikyoku reselect, characterized in that.

  A mobile communication terminal according to another aspect of the present invention includes one of a radio wave receiving unit that receives radio waves from a radio base station, and a radio base station that is a source of the radio waves received by the radio wave receiving unit. Radio base station selection means for selecting at random, and location registration request means for transmitting a location registration request for the mobile communication terminal to the radio base station selected by the radio base station selection means.

  According to the present invention, it is possible to preferably distribute the location registration requests transmitted simultaneously by many mobile communication terminals located in the vicinity to the radio base stations.

[First embodiment]
FIG. 1 is a diagram showing an example of the overall configuration of the mobile phone system 1, FIG. 2 is a diagram showing an example of the hardware configuration of the mobile phone terminal 2, and FIG. 3 shows an example of the functional configuration of the mobile phone terminal 2. FIG.

  As shown in FIG. 1, a mobile phone system 1 is a wireless communication system based on a standard such as CDMA2000 or W-CDMA, and includes a mobile phone terminal 2, a radio access network (RAN) 3 according to the present invention. And a core network (CN) 4.

  The configurations of the radio access network 3 and the core network 4 are the same as the conventional ones. That is, the radio access network 3 includes a radio base station (BS: Base Station) 31 and a base station controller (BSC: BS Controller) 32, and the core network 4 includes a gateway mobile switching center (GMSC: Gateway MSC) 41, A mobile services switching center (MSC) 42, a home location register (HLR) 43, and the like are included.

  The radio base station 31 may be referred to as “Node B” or “base station”. Further, the base station control device 32 may be referred to as “RNC (Radio Network Controller)”. Hereinafter, each radio base station 31 may be described separately as “radio base station 31A”, “radio base station 31B”, “radio base station 31C”,.

  The mobile phone terminal 2 makes a call with another mobile phone terminal or a fixed phone via the wireless access network 3 and the core network 4 as usual, or sends e-mail or image data with another mobile phone terminal or a personal computer. Etc. can exchange data.

  As shown in FIG. 2, the cellular phone terminal 2 includes a CPU 20a, a memory 20b, a wireless circuit 20c, a liquid crystal panel 20d, operation buttons 20e, an antenna 20f, a microphone 20g, a speaker 20h, an input / output interface 20i, and the like. Thus, the hardware configuration of the mobile phone terminal 2 is the same as the hardware configuration of the conventional mobile phone terminal.

  The software stored in the memory 20b is basically the same as the conventional one. However, as software for selecting the radio base station 31 to relay communication with the core network 4, the electric field strength measurement unit 201, the registration destination base station selection unit 202, the location registration execution unit 203, and the execution timer start shown in FIG. Software for realizing functions such as unit 204, execution timer expiration determination unit 205, position registration number recognition unit 206, position registration completion determination unit 207, execution number counter 2CR, and execution timer 2TR is stored. These software are executed by the CPU 20a.

  FIG. 4 is a diagram illustrating an example of the registration destination table TL. Next, the processing content of each part of the mobile phone terminal 2 shown in FIG. 3 will be described in detail.

  The electric field strength measuring unit 201 receives the strength of the radio wave from the radio base station 31 (that is, the electric field at the mobile phone terminal 2 due to the radio wave from the radio base station 31) received by the antenna 20f of the mobile phone terminal 2 itself. Strength) is measured by the same method as before.

  That is, the radio base station 31 normally transmits a radio wave that informs the identification information of the radio base station 31 using a channel of a predetermined frequency called “perch channel” or “common channel”. The field strength measuring unit 201 measures the field strength of the perch channel radio wave detected by the antenna 20f of the mobile phone terminal 2 itself as usual.

  Hereinafter, the electric field strength measured by the electric field strength measuring unit 201 is referred to as “electric field strength DK”. Further, the electric field strengths DK of the radio base stations 31A, 31B, 31C,... May be described separately from “electric field strength DKa”, “electric field strength DKb”, “electric field strength DKc”,.

  The location registration execution unit 203 makes a request for location registration of the mobile phone terminal 2 itself to the radio base station 31 selected by the registration destination base station selection unit 202 described later.

  Then, when the request is accepted by the radio base station 31 and the location information of the mobile phone terminal 2 is registered in the radio base station 31 and the upper home location register 43, another request is made via the core network 4 or the like. It becomes possible to communicate with a terminal device such as a mobile phone terminal, a fixed telephone, or a personal computer.

  The registration destination base station selection unit 202 is a radio base station 31 that relays communication between the mobile phone terminal 2 itself and the core network 4, that is, a radio base that is a registration destination of location information of the mobile phone terminal 2 itself. Processing for selecting the station 31 is performed. Such processing is performed based on the measurement result by the electric field strength measurement unit 201 and the registration destination table TL shown in FIG.

  Here, the registration destination table TL will be described. As described above in the section “Background Art”, when a plurality of wireless base stations 31 exist in the vicinity of the conventional mobile phone terminal, the wireless base station 31 associated with the highest (strong) electric field strength DK is used. Attempts to register location information (location registration). If the location registration fails, the electric field strength DK of each radio base station 31 is measured again after a predetermined time has elapsed, and the location registration to the radio base station 31 related to the highest electric field strength DK is performed. Tried.

  However, the mobile phone terminal 2 according to the present embodiment does not always attempt location registration to the radio base station 31 related to the highest electric field strength DK, but the second and subsequent heights according to the number of location registration attempts. The position registration to the radio base station 31 related to the electric field strength DK is also attempted. In the registration destination table TL, as shown in FIG. 4, depending on how many times the position registration is attempted, the position registration to the radio base station 31 related to the electric field strength DK of which strength is attempted. Is specified.

  The execution timer 2TR is a timer for adjusting the time interval of the above-described location registration trials to a predetermined time (hereinafter referred to as “time Ta”). The timer 2TR is started (started), and the execution timer expiration determination unit 205 determines that the execution timer 2TR has measured the time Ta.After the determination, the electric field intensity measurement unit 201 measures the electric field intensity DK, and the registration destination The base station selection unit 202 selects the radio base station 31 and the location registration execution unit 203 executes location registration processing.

  The execution number counter 2CR counts the number of the above-described position registration attempts. The position registration number recognizing unit 206 recognizes the number of times indicated by the execution number counter 2CR, and controls each unit as follows according to the recognized number of times. When the number of times is “2” or more, a command is given to the execution timer starting unit 204 to start the execution timer 2TR. If “1”, the field strength measurement unit 201 measures the field strength DK, the registration destination base station selection unit 202 selects the radio base station 31 without starting the execution timer 2TR, and the location registration execution unit 203 causes the location registration processing to be executed.

  The location registration completion determination unit 207 determines whether or not the location registration to the radio base station 31 and the home location register 43 has succeeded (completed).

  FIG. 5 is a flowchart for explaining an example of the flow of position registration processing. Here, the flow of registration processing of the location information of the mobile phone terminal 2 will be described with reference to FIG.

  When the mobile phone terminal 2 is powered on, the execution number counter 2CR is reset (# 1 in FIG. 5). The position registration number recognizing unit 206 recognizes the number of times indicated by the execution number counter 2CR and controls each unit according to the number of times. The first time (Yes in # 4), “1” is recognized, and an instruction is given to the electric field strength measurement unit 201, the registration destination base station selection unit 202, and the position registration execution unit 203 without starting the execution timer 2TR. give.

  Then, the electric field strength measuring unit 201 measures the electric field strength DK of each surrounding radio base station 31 (# 8). The registration destination base station selection unit 202 selects any one of the radio base stations 31 based on the registration destination table TL of FIG. 4 (# 9). Since this is the first trial, the radio base station 31 associated with the highest electric field strength DK is selected. Then, the location registration execution unit 203 makes a location registration request to the radio base station 31 selected by the registration destination base station selection unit 202 (# 10).

  If the position registration completion determination unit 207 determines that the position registration has been successful (Yes in # 2), the series of processes in FIG. Note that location registration is also performed for the home location register 43 as in the past.

  If the location registration cannot be performed (No in # 2), the execution number counter 2CR counts up by “1” (# 3), and tries to register the location again. However, it is executed after at least the time Ta has elapsed since the previous location registration attempt.

  That is, the execution timer starting unit 204 immediately starts the execution timer 2TR when it is found that the previous location registration has failed (# 5). When the execution timer expiration determination unit 205 determines that the time measured by the execution timer 2TR has passed the time Ta (Yes in # 7), the electric field intensity measurement unit 201 again determines the electric field intensity DK of each surrounding radio base station 31. Is measured (# 8). The registration destination base station selection unit 202 selects any one radio base station 31 based on the registration destination table TL (# 9). From the second time onward, the radio base station 31 related to the low electric field strength DK is gradually selected. Then, the location registration execution unit 203 executes location registration with the radio base station 31 selected by the registration destination base station selection unit 202 (# 10).

  The execution timer 2TR is stopped and reset every time the execution timer expiration determination unit 205 determines that the time Ta has elapsed. Further, the start (start) of the execution timer 2TR may not be the time when it is found that the previous location registration has failed. It may be activated in a time zone between the time when the previous position registration process is started and the time when it is found that the process has failed.

  FIG. 6 is a diagram illustrating an example of a cell in the vicinity of the facility and the state of the cellular phone terminal 2 when the power of the cellular phone terminal 2X is off, and FIG. 7 is a diagram of the facility after the cellular phone terminal 2X is powered on. It is a figure which shows the example of the mode of the cell of the vicinity of, and the state of the mobile telephone terminal 2. FIG.

  Next, immediately after the event being held in a facility such as a concert hall or a stadium is over, a visitor X's mobile phone terminal 2X in the case where the mobile phone terminal 2 is turned on at the same time is displayed. The location registration process will be described with reference to FIGS.

  When the event ends and the use of the mobile phone terminal is lifted, the visitors turn on their mobile phone terminals 2 all at once. Since visitors gather in a specific area, the location registration of their mobile phone terminals 2 is concentrated on a specific radio base station 31. In the example of FIG. 6, it is concentrated on the radio base station 31A.

  Here, when a certain visitor X turns on the power of his / her mobile phone terminal 2 (2X) later than other visitors, the mobile phone terminal 2X has a mobile phone as shown by a circled number in FIG. The electric field strengths DKa, DKb, and DKc of the radio base stations 31A, 31B, and 31C around the terminal 2X are measured. Here, it is assumed that the electric field strengths DKa, DKb, and DKc increase in this order. In the following description, for the sake of simplicity, the order of the electric field strengths DK will be assumed to be unchanged. In the figure, the one-dot chain circle represents the cell range of the radio base station 31A, the dotted circle represents the cell range of the radio base station 31B, and the solid circle represents the cell range of the radio base station 31C. ing.

  Then, based on the registration destination table TL (see FIG. 4), first, position registration to the radio base station 31 related to the highest electric field strength DK, that is, the radio base station 31A is attempted.

  If the location registration to the radio base station 31A fails, each field strength DK is measured again, and location registration is attempted based on the registration destination table TL. According to the registration destination table TL in FIG. 4, location registration is attempted for the radio base station 31 </ b> B for the second to fourth times, and location registration is attempted for the radio base station 31 </ b> C for the fifth to seventh times.

  According to the first embodiment, when the location registration is not successful, the mobile phone terminal 2 gradually shifts the destination of the location registration request to the radio base station 31 that is a weak radio wave source. Therefore, it is possible to preferably distribute the location registration requests transmitted simultaneously by a large number of mobile phone terminals 2 located in the vicinity to the radio base stations 31. Thereby, the certainty of position registration can be improved.

[Second Embodiment]
FIG. 8 is a diagram showing a modification of the functional configuration of the mobile phone terminal 2.

  In the first embodiment, when the mobile phone terminal 2 fails to register the location in the radio base station 31 related to the strongest electric field strength DK, the mobile phone terminal 2 gradually shifts to the radio base station 31 related to the lower electric field strength DK. Retry location registration. In the second embodiment, the cellular phone terminal 2 randomly selects the radio base station 31 and attempts location registration.

  The hardware configuration of the mobile phone terminal 2 in the second embodiment is the same as that of the second embodiment, as shown in FIG. The installed software is basically the same as in the second embodiment. However, as software for selecting the radio base station 31, the electric field strength measurement unit 221, the registration destination base station selection unit 222, the location registration execution unit 223, the execution timer start unit 224, the execution timer expiration determination unit 225, and the position shown in FIG. Software for realizing functions such as a registration number recognition unit 226, a position registration completion determination unit 227, a random number calculation unit 228, an execution number counter 2CS, and an execution timer 2TS is stored.

  The electric field strength measurement unit 221, the position registration execution unit 223, the execution timer start unit 224, the execution timer expiration determination unit 225, the position registration number recognition unit 226, the position registration completion determination unit 227, the execution number counter 2CS, and the execution timer 2TS The electric field strength measurement unit 201, the position registration execution unit 203, the execution timer start unit 204, the execution timer expiration determination unit 205, the position registration number recognition unit 206, the execution number counter 2CR, and the execution timer 2TR according to the first embodiment, respectively. Equivalent processing is performed.

  Based on the number of electric field strengths DK detected (measured) by the electric field strength measurement unit 221, the random number calculation unit 228 selects any of the radio base stations 31 that transmit radio waves that can be received by the mobile phone terminal 2 at present. Generate a random number of natural numbers to select. That is, when the field strength measurement unit 221 detects the field strength DK from the N wireless base stations 31, any one of “1” to “N” (N is a natural number of 2 or more) is used as a random number. To generate. The value of the current execution number counter 2CR may be used as one argument of a function for generating a random number. The value of another item may be used as an argument.

  Similar to the registration destination base station selection unit 202, the registration destination base station selection unit 222 is a radio base station 31 that relays communication between the mobile phone terminal 2 itself and the core network 4, that is, the mobile phone terminal 2. A process of selecting a radio base station 31 as a registration destination of its own location information is performed. However, the selection method is different from the method in the registration destination base station selection unit 202.

  That is, the registration destination base station selection unit 222 selects the radio base station 31 corresponding to the random number generated by the random number calculation unit 228 as the registration destination of the position information. The association between the random number and the radio base station 31 may be determined in advance as follows. For example, random numbers “1”, “2”, “3”,... May be associated in descending order of the electric field strength DK. Alternatively, random numbers may be associated in ascending order of identification information.

  FIG. 9 is a flowchart for explaining a modified example of the flow of the position registration process. Next, the flow of registration processing of location information of the mobile phone terminal 2 in the second embodiment will be described with reference to FIG.

  The contents of the processing of steps # 21 to # 28 are the same as those of steps # 1 to # 8 of the first embodiment described in FIG. That is, when the mobile phone terminal 2 is turned on, the execution number counter 2CS is reset (# 21 in FIG. 9). The position registration number recognition unit 226 recognizes the number of times indicated by the execution number counter 2CS and controls each part according to the number of times. The first time (Yes in # 24), “1” is recognized, and an instruction is given to the electric field strength measurement unit 221, the registration destination base station selection unit 222, and the location registration execution unit 223 without starting the execution timer 2TS. give.

  Then, the electric field strength measuring unit 221 measures the electric field strength DK of each surrounding radio base station 31 (# 28). After the measurement, the random number calculation unit 228 is activated (# 29) and generates a random number corresponding to the number of surrounding radio base stations 31 (# 30).

  The registration destination base station selection unit 222 selects the radio base station 31 according to the random number (# 31). Then, the location registration execution unit 223 makes a location registration request to the radio base station 31 selected by the registration destination base station selection unit 202 (# 32).

  When the position registration completion determination unit 207 determines that the position registration is successful (Yes in # 22), the series of processes in FIG. The location registration is also performed on the home location register 43 as in the first embodiment.

  If the location registration could not be performed (No in # 22), the execution number counter 2CS counts up by “1” (# 23), and tries to register the location again. Similar to the first embodiment (# 25 to # 27), the process is executed after at least the time Ta has elapsed since the previous position registration attempt. However, at this time, in the second embodiment, the failed radio base station 31 is excluded, and one of the remaining communicable radio base stations 31 is reselected at random (# 28 to # 31). . Instead of reselecting the radio base station 31 every time it fails, it may be selected again if the location registration is not possible after a predetermined number of attempts.

  According to the second embodiment, the mobile phone terminal 2 randomly selects the radio base station 31 that is the transmission destination of the location registration request. Therefore, it is possible to preferably distribute the location registration requests transmitted simultaneously by a large number of mobile phone terminals 2 located in the vicinity to the radio base stations 31.

  In the second embodiment, the wireless base station 31 is randomly selected from the first time and the location registration process is performed. However, the first time, the wireless base station 31 related to the highest electric field strength DK is selected as in the first embodiment. If the location registration processing is selected and fails, the location registration processing may be performed by reselecting one of the remaining radio base stations 31 at random.

  In the first and second embodiments, the registration destination base station selection units 202 and 222 set all the radio base stations 31 related to the electric field strength DK measured by the electric field strength measurement units 201 and 221 as selection candidates. Instead, it is desirable to exclude the radio base station 31 related to the weak electric field strength DK that is less than the predetermined value from the candidates.

  In the first and second embodiments, the cellular phone terminal 2 (mobile station) used in a wireless communication system based on a standard such as CDMA2000 or W-CDMA has been described as an example. The present invention is also applicable to mobile stations of other types of wireless communication systems such as mobile stations or PHS mobile stations.

  In addition, the configuration of the entire mobile phone system 1 and the mobile phone terminal 2 or each unit, the processing content, the processing order, the configuration of the registration destination table TL, and the like can be appropriately changed in accordance with the spirit of the present invention.

In the embodiment described above, the following notes are also disclosed.
(Appendix 1)
A mobile communication terminal that communicates wirelessly,
A received radio field intensity measuring means for measuring the intensity of a received radio wave received from a radio base station;
A radio base station selecting means for selecting to which radio base station a request for location registration of the mobile communication terminal is transmitted;
Location registration request means for transmitting the request to the radio base station selected by the radio base station selection means,
The radio base station selecting means selects the radio base station related to the received radio wave having the highest intensity measured by the received radio wave intensity measuring means for the first time when newly transmitting the request, If the location registration related to the request transmitted to the radio base station fails, reselect a radio base station related to another received radio wave that is less than or equal to the intensity of the received radio wave related to the radio base station,
A mobile communication terminal characterized by the above.
(Appendix 2)
A mobile communication terminal that communicates wirelessly,
Radio wave receiving means for receiving radio waves from a radio base station;
A radio base station selection means for randomly selecting one of radio base stations that are sources of radio waves received by the radio wave reception means;
Location registration requesting means for transmitting a request for location registration of the mobile communication terminal to the radio base station selected by the radio base station selecting means;
A mobile communication terminal characterized by comprising:
(Appendix 3)
When the location registration related to the request transmitted to any one of the radio base stations fails, the radio base station selection unit excludes the radio base station and transmits the radio wave received by the radio wave reception unit. Reselect one of the original radio base stations,
The mobile communication terminal according to attachment 2.
(Appendix 4)
The radio base station selection means excludes a radio base station that is a source of radio waves whose intensity measured by the received radio field intensity measurement means is less than a predetermined value from selection targets,
The mobile communication terminal according to attachment 3.
(Appendix 5)
A mobile communication terminal that communicates wirelessly,
A received radio field intensity measuring means for measuring the intensity of a received radio wave received from a radio base station;
A radio base station selecting means for selecting to which radio base station a request for location registration of the mobile communication terminal is transmitted;
Location registration request means for transmitting a request for location registration of the mobile communication terminal to the radio base station selected by the radio base station selection means,
The radio base station selection means, when transmitting the request anew, selects the radio base station related to the received radio wave having the highest intensity measured by the received radio wave intensity measurement means for the first time, When such location registration fails, one of the radio base stations related to the received radio wave having the second highest intensity measured by the received radio wave intensity measuring unit is randomly selected again.
A mobile communication terminal characterized by the above.
(Appendix 6)
A location registration method for a mobile communication terminal that communicates wirelessly,
In the mobile communication terminal,
Send a request for location registration of the mobile communication terminal to the radio base station that is the source of the strongest radio wave of the radio waves that have reached the mobile communication terminal,
If the location registration fails, the request is retransmitted to the radio base station that is the second strongest source of radio waves that have reached the mobile communication terminal.
A location registration method for a mobile communication terminal.
(Appendix 7)
A location registration method for a mobile communication terminal that communicates wirelessly,
In the mobile communication terminal,
Receive radio waves from wireless base stations,
Randomly select one of the wireless base stations that is the source of the received radio waves,
Sending a request for location registration of the mobile communication terminal to the selected radio base station;
A location registration method for a mobile communication terminal.
(Appendix 8)
A computer program used to control a mobile communication terminal that communicates wirelessly,
In the mobile communication terminal,
Execute a process of transmitting a request for location registration of the mobile communication terminal to the radio base station that is the source of the strongest radio wave among the radio waves that have reached the mobile communication terminal,
When the location registration fails, the request is retransmitted to a radio base station that is the second strongest source of radio waves that have reached the mobile communication terminal.
A computer program characterized by the above.
(Appendix 9)
A computer program used to control a mobile communication terminal that communicates wirelessly,
In the mobile communication terminal,
A process of randomly selecting one of the radio base stations that are the sources of the received radio waves,
Processing for transmitting a request for location registration of the mobile communication terminal to the selected radio base station,
A computer program characterized by the above.

It is a figure which shows the example of the whole structure of a mobile telephone system. It is a figure which shows the example of the hardware constitutions of a mobile telephone terminal. It is a figure which shows the example of a functional structure of a mobile telephone terminal. It is a figure which shows the example of a registration destination table. It is a flowchart explaining the example of the flow of a position registration process. It is a figure which shows the example of the mode of the cell near a plant | facility, and a mobile telephone terminal when the power supply of a mobile telephone terminal is OFF. It is a figure which shows the example of the mode of the cell near the plant | facility after the power supply of a mobile telephone terminal is turned on, and a mobile telephone terminal. It is a figure which shows the modification of a functional structure of a mobile telephone terminal. It is a flowchart explaining the modification of the flow of a position registration process.

2 Mobile phone terminals (mobile communication terminals)
201, 221 Electric field strength measuring unit (Receiving radio wave strength measuring means)
202, 222 Registration destination base station selection section (radio base station selection means)
203, 223 Location registration execution unit (location registration request means)
20f Antenna (radio wave receiving means)
31 Radio base station

Claims (5)

A mobile communication terminal that communicates wirelessly,
Radio wave receiving means for receiving radio waves from a radio base station;
A radio base station selection means for randomly selecting one of radio base stations that are sources of radio waves received by the radio wave reception means;
Location registration requesting means for transmitting a request for location registration of the mobile communication terminal to the radio base station selected by the radio base station selecting means;
A mobile communication terminal characterized by comprising: When the location registration related to the request transmitted to any one of the radio base stations fails, the radio base station selection unit excludes the radio base station and transmits the radio wave received by the radio wave reception unit. Reselect one of the original radio base stations,
The mobile communication terminal according to claim 1. The radio base station selection means excludes a radio base station that is a source of radio waves whose intensity measured by the received radio field intensity measurement means is less than a predetermined value from selection targets,
The mobile communication terminal according to claim 2. A location registration method for a mobile communication terminal that communicates wirelessly,
In the mobile communication terminal,
Receive radio waves from wireless base stations,
Randomly select one of the wireless base stations that is the source of the received radio waves,
Sending a request for location registration of the mobile communication terminal to the selected radio base station;
Location registration method for mobile communication terminal A computer program used to control a mobile communication terminal that communicates wirelessly,
In the mobile communication terminal,
Execute the process of receiving radio waves from the wireless base station,
A process of randomly selecting one of the radio base stations from which the received radio wave is transmitted,
Causing the selected radio base station to execute a process of transmitting a request for location registration of the mobile communication terminal;
A computer program characterized by the above.

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