JP4790852B2 - Wireless terminal device and handoff control method in wireless terminal device - Google Patents

Description

  The present invention particularly relates to a wireless terminal device and a handoff control method in the wireless terminal device that are suitable for use in an emergency information distribution system that can receive emergency information such as disaster prevention / crime prevention information.

  A system for notifying a mobile phone of disaster information is known (for example, Patent Documents 1, 2, 3, and 4).

  In particular, Patent Literature 4 uses a broadcast-type short message service (BCSMS), so that disaster prevention / crime prevention information in the vicinity of the current location can be obtained without registering the location in advance. An emergency information distribution system that can receive emergency information is disclosed. For example, when a disaster such as an earthquake is predicted in a predetermined area, a disaster forecast is simultaneously broadcast to the corresponding area.

JP 2001-168990 A JP 2004-96458 A JP 20065412 A JP 2007-148837 A

  However, when an unexpected situation such as a disaster occurs, there are many cases in which reception failure, congestion, etc. occur due to the concentrated movement of the user. In this case, the user can effectively utilize the above-mentioned notification type short message service. It had the inconvenience of not being removed.

  An object of the present invention is to provide a wireless terminal device and a handoff control method in the wireless terminal device that enable a user to effectively use a broadcast-type short message service.

A wireless terminal device according to a first aspect of the present invention includes a communication unit capable of performing wireless communication with a plurality of base stations, and the communication from a standby base station waiting in the communication unit to other neighboring base stations. A control unit having handoff processing means for causing the unit to perform handoff, and the control unit regulates the handoff when receiving emergency information based on broadcast information from a base station waiting in the communication unit. To do.
Preferably, the control unit regulates the handoff by regulating a change in location registration from the standby base station to the other base station.

  Preferably, the emergency information is broadcast information specified by the broadcast information.

  Preferably, the broadcast information is received in a broadcast slot which is a reception time slot of a paging channel established by the broadcast information.

  Preferably, the emergency information is specified in broadcast information received in a standby slot in cases other than emergency information based on the broadcast information.

  Preferably, the control unit cancels the handoff restriction when emergency information is not received based on broadcast information from the base station.

  Preferably, upon receiving the emergency information, the control unit sets a timer for restricting the location registration before attempting location registration, and controls the change of the location registration triggered by detection of a timeout of the timer. Is released.

  Preferably, the timer is determined by a random number.

  A second aspect of the present invention is a handoff control method in a wireless terminal device including a communication unit capable of performing wireless communication with a plurality of base stations, and is located near a standby base station waiting in the communication unit. Causing another base station to perform handoff to the communication unit; receiving broadcast information from a base station waiting in the communication unit; receiving emergency information based on the broadcast information; And, when the emergency information is received, restricting the handoff.

  According to the present invention, a user can effectively use a notification-type short message service.

It is a figure which shows the BCSMS transmission image by the communication system with which the wireless terminal device which concerns on embodiment of this invention is connected. It is a figure for demonstrating the BC slot monitoring operation in the slot mode of BCSMS. It is a block diagram which shows an example of the signal processing system of the radio | wireless terminal apparatus which concerns on embodiment of this invention. It is a flowchart which shows the threshold value change operation | movement of the radio | wireless terminal apparatus which concerns on embodiment of this invention. It is a flowchart which shows the position registration control operation | movement of the radio | wireless terminal apparatus which concerns on embodiment of this invention. It is a flowchart which shows the position registration operation | movement of the radio | wireless terminal apparatus which concerns on embodiment of this invention.

  Hereinafter, a wireless terminal apparatus according to an embodiment of the present invention will be described with reference to the drawings.

  First, broadcast distribution related to the wireless terminal device according to the embodiment of the present invention will be described.

FIG. 1 is a diagram showing a BCSMS transmission image by a communication system to which a wireless terminal device according to an embodiment of the present invention is connected.
2A, 2B, 2C, and 2D are diagrams for explaining the BC slot monitoring operation in the slot mode of BCSMS.

One broadcast distribution service is a broadcast-type short message service (BCSMS).
As shown in FIG. 1, the BCSMS is generally transmitted for each cover area of the base station 100. The range is determined by the carrier, but it spans hundreds to kilometers, so it can be a single commercial facility (shopping center), sports facility (stadium), event venue, etc. This is larger than the maximum unit in which humans (users who have the mobile phone 10) having the purpose of

  Therefore, according to the normal BCSMS distribution, a service for notifying information limited to a specific area only to a user currently located in that area could not be realized. is there. In FIG. 1, a thick solid arrow indicates a BCSMS transmission image (distribution itself is possible, but information is also distributed to users located in other areas).

By the way, when the BCSMS is transmitted from the base station, the BCSMS receives a broadcast message in which a broadcast index (BCAST_INDEX) is set, and can know in advance that the BCSMS is broadcast in the BC slot.
The broadcast index (BCAST_INDEX) is a parameter that specifies slot monitoring timing.
Also, a broadcast address (BC_ADDR) is set in the received message. In the broadcast address (BC_ADDR), a BCSMS message number (MESSAGE_ID), a zone (ZONE_ID), a priority (PRIORITY), a language (LANGUAGE), a service identifier (SERVICE) indicating the type of service category, and the like are set.

In the BCSMS, reception determination is made from a combination of a priority (PRIORITY), a service identifier (SERVICE), and a language (LANGUAGE) among the fields set in the broadcast address (BC_ADDR).
In addition, the wireless terminal device holds a list of BCSMSs that can be received therein, and whether or not reception is possible in the wireless terminal device is determined by this combination. The BCSMS is transmitted to a specific slot (BC slot) on the paging channel.

FIGS. 2A, 2B, 2C, and 2D show examples of paging channel monitoring including the BC slot monitoring timing (slot mode).
Here, FIG. 2 (a) shows a slot mode when there is no BCSMS reception setting, FIG. 2 (b) shows a slot mode when there is BCSMS reception setting, FIG. 2 (c) shows normal monitoring timing, and FIG. The BC slot monitoring timing is shown in FIG.

As shown in FIGS. 2A, 2B, 2C, and 2D, the BC slot is determined in a different cycle from the normal monitoring timing (standby slot).
Then, monitoring is performed by a wireless terminal device capable of receiving a combination of at least one broadcast address (BC_ADDR) and a wireless terminal device in which the slot has become a normal standby slot.
The wireless terminal device can receive BCSMS on the BC slot and performs reception processing when determining that reception is possible from the content of the broadcast address (BC_ADDR). Here, the reception processing means decoding, storing data, and notifying the user of the reception.

  As described above, the wireless terminal device can receive a message including the broadcast index (BCAST_INDEX) before receiving BCSMS. It is necessary to consider that this information is used to reduce BCSMS reception omission and that the communication system is less likely to be congested due to user movement after reception.

  By the way, the advantage of BCSMS is that the wireless terminal device can receive while waiting, and further, access to the base station 100 does not occur for reception. Therefore, it is possible to minimize the amount of current consumed by the wireless terminal device for information reception (consumption amount that is almost the same as that during standby). In addition, since resources for communication are not occupied, there is an advantage that problems such as system congestion do not occur.

  However, since BCSMS is also used for emergency bulletins when earthquakes occur, location registration processing occurs when a large number of users concentrate and move when receiving BCSMS, and a large amount of access occurs simultaneously. Such a situation can also be considered. In addition, since emergency information such as emergency bulletin is notified by BCSMS, reception of emergency bulletin may occur when handoff or reselection occurs.

  In order to reduce BCSMS reception omission, it is necessary to perform control so that the BC slot cannot be monitored, such as selection of a communication system or out of service area, at the timing at which BCSMS is notified.

  For this reason, in the wireless terminal device according to the embodiment of the present invention, the timing at which BCSMS is broadcast is known in advance by the value of the broadcast index (BCAST_INDEX). The threshold value to be transferred is temporarily changed to perform control that makes it difficult to shift to the communication system selection process. Moreover, since the timing at which BCSMS is notified is known in advance by the value of the broadcast index (BCAST_INDEX), when it is determined that notification is to be made, the threshold value for performing idle handoff is temporarily changed, and idle handoff is unlikely to occur. It was decided to control to such a state.

On the other hand, in order to avoid system congestion due to a user's concentrated movement or the like, it is necessary to suppress the occurrence of position registration executed when the position registration zone due to movement is changed.
For this reason, in the radio | wireless terminal apparatus which concerns on embodiment of this invention, when the received BCSMS was emergency bulletin, it decided to suppress generation | occurrence | production of the location registration process by a movement. In addition, when the received BCSMS is an emergency bulletin, the threshold for performing idle handoff is temporarily raised, and control is performed so that idle handoff due to movement is unlikely to occur.

  By controlling in this way, it is possible to suppress BCSMS reception omission and prevent system congestion at the time of emergency early warning due to BCSMS reception.

  Hereinafter, when receiving an emergency information service using BCSMS, a radio terminal apparatus capable of avoiding a functional failure due to congestion so that there is no reception omission for the user and for the system side including the base station Will be described in detail with reference to FIG.

  FIG. 3 is a block diagram showing an example of a signal processing system of the wireless terminal device according to the embodiment of the present invention. Here, a mobile phone 10 is illustrated as a wireless terminal device.

  As shown in FIG. 3, the mobile phone 10 has a control unit 17 as a control center, a communication unit 11, an operation unit 12, a voice input / output unit 13, a display unit 14, an imaging unit 15, and a storage unit. 16 and the control unit 17 are commonly connected to a bidirectional system bus 18 having a plurality of lines for address, data, and control.

The communication unit 11 captures a wireless communication system, performs wireless communication with a base station (100 in FIG. 1) connected to the public communication network, and transmits and receives various data. Here, the various data includes voice data at the time of voice call, mail data at the time of mail transmission / reception, web page data at the time of browsing the web, and the like.
As will be described later, the communication unit 11 receives broadcast information (BCSMS) on a paging channel transmitted from the base station 100 based on a predetermined time slot (BC slot) or a predetermined packet.

The operation unit 12 includes keys to which various functions are assigned, such as a power key, a call key, a numeric key, a character key, a direction key, a determination key, a call key, and a function key.
When these keys are operated by the operator, the operation unit 12 generates a signal corresponding to the operation content and outputs the signal to the control unit 17 as an instruction from the operator.

The audio input / output unit 13 performs input / output processing of an audio signal output from a speaker or an audio signal input from a microphone.
That is, the voice input / output unit 13 amplifies the voice input from the microphone, performs analog-digital conversion, further performs signal processing such as encoding, converts it into digital voice data, and outputs it to the control unit 17. .
The audio input / output unit 13 performs signal processing such as decoding, digital-analog conversion, and amplification on the audio data supplied from the control unit 17, converts the audio data into an analog audio signal, and outputs the analog audio signal to the speaker.

The display unit 14 is configured by arranging a large number of pixels (a combination of light emitting elements of a plurality of colors) vertically and horizontally, for example, a liquid crystal display (LCD) or an organic EL display (OLED: Organic Light Emitted Diode). And an image corresponding to the video signal supplied from the control unit 17 is displayed.
The display unit 14 is, for example, a telephone number of a transmission destination at the time of wireless transmission by the base station communication unit 11, a telephone number of a transmission source at the time of incoming call, contents of received mail or transmitted mail, date, time, remaining battery level, success / failure of transmission The standby screen is displayed.

  The imaging unit 15 is a camera configured by a photoelectric conversion element such as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) image sensor, a control circuit thereof, and the like.

The storage unit 16 stores various data used for various processes of the mobile terminal 10.
The storage unit 16 includes, for example, a computer program executed by the control unit 17, an address book for managing personal information such as a telephone number and an e-mail address of a communication partner, an audio file for reproducing a ring tone and an alarm sound, and a standby An image file for a screen, various setting data, and temporary data used in the program processing are stored.
Here, the storage unit 16 further stores a threshold value change flag 161 and a position registration control flag 162 assigned to predetermined areas. The role of these flags 161 and 162 will be described later.
The storage unit 16 includes, for example, a nonvolatile storage device (nonvolatile semiconductor memory, hard disk device, optical disk device, etc.), a randomly accessible storage device (eg, SRAM, DRAM), or the like.

The control unit 17 comprehensively controls the overall operation of the mobile phone 10.
That is, the control unit 17 controls the operation of each block described above so that various processes of the mobile phone 10 are executed in an appropriate procedure according to the operation of the operation unit 12. Note that the various types of processing include voice calls performed via a circuit switching network, creation and transmission / reception of electronic mail, browsing of the Internet Web (World Wide Web) site, and the like. The operation of each block includes transmission / reception of a signal in the base station communication unit 11, display of an image on the display unit 14, and the like.
The control unit 17 includes a computer (microprocessor) that executes processing based on a program (operating system, application program, etc.) stored in the storage unit 16. The control unit 17 executes the processing described above according to the procedure instructed in this program. That is, instruction codes are sequentially read from programs such as an operating system and application programs stored in the storage unit 16 to execute processing.

The control unit 17 changes the communication system used by the communication unit 11 to perform wireless communication, monitors the signal strength from the base station that is waiting in the communication unit 11, and sets the signal strength to a preset number. Handoff processing means for causing the communication unit 11 to perform handoff based on the relationship with the threshold value of 1. And the control part 17 will change a 1st threshold, if emergency information is received based on the alerting | reporting information from the base station which is waiting in the communication part 11. FIG.
The communication unit 11 can select one of a plurality of communication systems and wirelessly communicate with the base station, and the control unit 17 can control the signal strength of the communication system used by the communication unit 11. To monitor. Further, the control unit 17 releases the communication system in use in the communication unit 11 based on the relationship between the signal strength and the preset second threshold value, and any one of the plurality of communication systems is assigned to the communication unit 11. Reselection processing means for performing reselection processing for controlling reselection is further provided. And control part 17 will change also about the 2nd threshold, if emergency information is received.
Here, the emergency information is broadcast information specified by the broadcast information. Also, the broadcast information is received in a BC slot which is a reception time slot established by broadcast information, or is specified in broadcast information received in a normal standby slot in cases other than emergency information based on broadcast information Is the same.

The handoff processing means controls to perform the handoff processing when the signal strength from another base station is better than the signal strength from the waiting base station and the difference exceeds the first threshold value. Moreover, the control part 17 will change so that a 1st threshold value may be enlarged, when emergency information is received. On the other hand, the reselection processing unit controls the reselection processing handoff process to be performed when the signal strength of the communication system used in the communication unit 11 is smaller than the second threshold. Is received, the second threshold value is changed to be smaller.
Moreover, the control part 17 returns the said threshold value to the threshold value before a change, when emergency information is no longer received based on the alerting | reporting information from the said base station.

In addition, when the emergency information is received, the control unit 17 sets information for restricting location registration before attempting location registration, and activates a built-in timer (location registration control timer 170), and the location registration control timer. Location registration is performed in response to the time-out detection at 170.
At this time, the control unit 17 detects the timeout of the location registration control timer 170 whose timing is different for each terminal and performs location registration.

4 to 6 are flowcharts showing the operation of the wireless terminal device according to the embodiment of the present invention. FIG. 4 shows the operation when the threshold is changed, FIG. 5 shows the location registration control, and FIG. Each registration operation is shown.
Hereinafter, the operation of the control unit 17 shown in FIG. 3 will be described in detail with reference to the flowcharts of FIGS. 4 to 6.

When the reception environment changes due to movement of the user or the like, idle handoff for selecting a better standby channel or reselection operation of the communication system due to environmental degradation is performed based on the value held in the mobile phone 10.
Due to these operations, there is a case where the BC slot cannot be monitored until the mobile phone 10 disconnects the communication system once waiting and moves to another communication system. If BCSMS is distributed from the base station during this period, reception will be missed, and if the information distributed by BCSMS is urgent breaking news, the information will not be obtained, resulting in a dangerous situation for the user. May occur.

For this reason, in the wireless terminal device according to the embodiment of the present invention, the timing at which BCSMS is broadcast is known in advance by the value of the broadcast index (BCAST_INDEX). Control that makes it difficult to shift to the communication system selection processing by temporarily raising the threshold value to be shifted is performed.
In addition, since the timing at which BCSMS is notified is known in advance by the value of the broadcast index (BCAST_INDEX), when it is determined that notification is to be made, the threshold value for performing idle handoff is temporarily raised so that idle handoff is unlikely to occur. It was decided to control to a proper state.

Specifically, BCSMS is distributed in a BC slot different from the standby slot. For this reason, the base station 100 sets the value of the broadcast index (BCAST_INDEX) that is a parameter of the broadcast message on the standby slot to a value other than 0 (1 to 7) on the standby slot before delivering BCSMS in the BC slot, and the BC slot uses BCSMS. Notify that will be sent.
The mobile phone 10 can confirm the timing at which the BCSMS is broadcasted by the broadcast index (BCAST_INDEX) and that the BCSMS is distributed by the broadcast address (BC_ADR) of the broadcast message.

As shown in the threshold value change flowchart of FIG. 4, the control unit 17 monitors the BC slot at the timing specified by the broadcast index (BCAST_INDEX) of the broadcast information message from the base station 100, and also broadcast address (BC_ADR) Is monitored (step S101).
When the broadcast index (BCAST_INDEX) value is other than “0” (step S102 “Yes”), the control unit 17 adds the BCSMS reception threshold value (α dB) to the reception level threshold value for starting the idle handoff, and temporarily Therefore, the threshold value is changed to a level at which idle handoff is difficult to start (step S103).
Further, the control unit 17 adds the BCSMS reception threshold (β dB) to the reception level threshold for starting communication system selection, and temporarily changes the threshold to a level at which it is difficult to start the communication system selection operation by reselection (step S104).
The details of changing the threshold will be described later.

  Subsequently, the control unit 17 performs a process of notifying that the idle handoff and the communication system selection threshold are changed by setting the threshold change flag 161 assigned to a predetermined area of the storage unit 16 to ON (TRUE) ( Step S105).

On the other hand, when the parameter value of the broadcast index (BCAST_INDEX) is “0” or when the BCSMS distribution ends (step S102 “No”), the control unit 17 matches the broadcast address (BC_ADR) with its own address. It is determined whether or not to perform (step S106).
If the addresses do not match (step S106 “No”), the control unit 17 further determines the state of the threshold value change flag (step S107). If the threshold value change flag 161 is ON (TRUE) (step S107 “Yes”), the idle handoff threshold value is initialized and returned to the original handoff threshold value (step S108), and the reselection threshold value is initialized. To the communication system selection threshold value (step S109). Subsequently, the control unit 17 sets the threshold value change 161 flag to OFF (FALE) and ends the series of processes described above (step S110).

  If the addresses match in step S106 (step S106 “Yes”), the threshold value changing process after step S103 is executed, and if the threshold value change flag is set OFF in step S107 (step S107 “ No "), the above-described series of processing ends.

First, the handoff threshold will be described.
The control unit 17 constantly monitors the signal strength of the radio signal from the base station waiting in the communication unit 11. Furthermore, the signal strength of radio signals from other base stations is also monitored, and handoff control is performed by comparing these signal strengths. In the embodiment of the present invention, idle handoff is taken as an example, but the same applies during communication. Then, the control unit 17 performs communication so that the handoff process is performed when the signal strength of the handoff candidate base station is larger than that of the standby base station and the difference exceeds the handoff determination threshold (first threshold). The unit 11 is controlled. In other words, “adding a BCSMS communication threshold (αdB) to make it difficult to perform handoff” means increasing αdB so as to increase the handoff determination threshold (first threshold).
Next, the reselection threshold will be described.
As in the case of handoff, the control unit 17 constantly monitors the signal strength of the radio signal from the base station waiting in the communication unit 11. In particular, attention is paid to which communication system is in use. When the signal intensity falls below the threshold value (second threshold value) for the reselection execution determination and it is determined that the communication system should be reselected, the communication unit 11 is controlled to perform the reselection process. In other words, “adding a BCSMS reception threshold (β dB) to make the environment in which reselection hardly occurs” means to reduce β dB so as to reduce the threshold for reselection determination (second threshold).
In this way, the occurrence of handoff or system reselection (reselection) can be suppressed by changing the handoff and reselection thresholds.
In addition, in the case of a configuration that has a timer that starts timing based on a predetermined operation such as the end of communication and the occurrence of reselection is managed by a timeout of this timer, the timer time is changed. Anyway. Specifically, the BCSMS reception timer may be extended when “an environment in which reselection is difficult to occur by adding a BCSMS reception threshold” is set. Such a configuration can also suppress the reselection.

In addition, the location registration thorn may be changed when the user moves in response to an emergency bulletin notified by BCSMS. When the location registration zone is changed, it is necessary to perform a location registration operation called Zone Based Registration according to the standard, and access to the base station 100 occurs.
However, since BCSMS is distributed to an unspecified number of people in the area, a large number of users who have received evacuation advisories, such as emergency bulletins, may move to the same zone all at once. In this case, a large number of mobile phones 10 access the base station 100 all at once, and it is expected that the system will be temporarily congested. When the system is congested, confusion occurs due to the difficulty of making a call, resulting in a disadvantage for the user.

For this reason, in order to avoid system congestion due to the concentrated movement of users, etc., it is necessary to suppress the occurrence of position registration executed when the position registration zone due to movement is changed.
For this reason, in the radio | wireless terminal apparatus which concerns on embodiment of this invention, when the received BCSMS was emergency bulletin, it decided to suppress generation | occurrence | production of the location registration process by a movement. In addition, when the received BCSMS is an emergency bulletin, the threshold for performing idle handoff is temporarily raised, and control is performed so that idle handoff due to movement is unlikely to occur.

Specifically, as shown in the location registration control flowchart of FIG. 5, the control unit 17 monitors the BC slot at the timing specified by the broadcast index (BCAST_INDEX) of the broadcast information message from the base station 100, and BCSMS Is received (step S201).
If it is determined that the content of the received BCSMS is emergency bulletin (step S202 “Yes”), the control unit 17 sets the position registration control flag 162 assigned and set to a predetermined area of the storage unit 16 to ON ( TRUE (step S203), and the built-in location registration control timer 170 is started (step S204).
Even when the location registration zone is changed, the control unit 17 does not generate Zone Based Registration but activates the location registration control timer 170 in which the count value is defined by a random number when receiving an emergency bulletin.
Incidentally, the position registration control timer 170 has different initial values set by the terminal.

On the other hand, when it is determined that the content of the BCSMS received in step S202 is other than emergency warning (step S202 “No”), the control unit 17 determines whether or not the location registration control timer 170 has expired (timed out). (Step S205). If it has expired (step S205 “Yes”), the location registration control flag 162 is set to OFF (FALSE), and the above-described series of processing ends (step S206).
When the emergency information is received, the control unit 17 sets the location registration control flag 162 to ON (TRUE) before the location information registration in order to control the traffic when the access is concentrated. Is set (step S203), and the location registration control timer 170 is started (step S204). When the time-out of the location registration control timer 170 is detected, the location registration control flag is turned off to perform location registration processing.

That is, in the location registration flowchart of FIG. 6, when the location registration condition is satisfied, specifically, when the location registration control timer 170 times out (step S211), the control unit 17 determines whether the location registration control flag 162 is TRUE. Determine whether or not. As a result, in the case of FALSE (step S212 “No”), the location registration process is executed for the first time (step S213).
In addition, although the count value is defined by the random number in the location registration control timer 170, for example, a value obtained by counting 0 to 9 using the lower 1 bit of the terminal ID unique to the terminal may be used. In any case, it is sufficient that the timing of timeout for each terminal does not match between terminals. This avoids concentration of location registration processing.

  By controlling as described above, when emergency information is notified by BCSMS, a large number of mobile phones 10 do not access the network side devices including the base station all at once. A state can be avoided.

As described above, according to the wireless terminal device according to the embodiment of the present invention, information distribution by BCSMS can be performed by knowing BCSMS reception in advance and automatically changing parameters of the handoff threshold and the communication system selection threshold. It is possible to construct an environment in which reception can be performed even in a situation in which reception omissions are likely to occur due to concentration of user movements. In addition, convenience is improved because it is realized without user operation or normal communication, that is, without the user being aware of it. Furthermore, by controlling the traffic at the time of location registration processing, system congestion is less likely to occur, so that an emergency line can be secured and user convenience is improved.
In this way, simultaneous movement of users during emergency information notification is predicted, but this can prevent a large number of location registrations from occurring simultaneously, and avoiding congestion can also improve the probability of successful transmission at the time of disaster occurrence In addition, it can contribute to ensuring the safety of the user.

  Note that only the mobile phone 10 is illustrated as the wireless terminal device according to the above-described embodiment of the present invention. However, for example, a PDA (Personal Digital Assistants), an electronic notebook, and a game machine can be used as long as they have the same configuration. The same applies.

Further, all the functions of the control unit 17 shown in FIG. 3 may be realized by software, or at least a part thereof may be realized by hardware.
For example, when emergency information is received based on broadcast information from a base station, data processing in the control unit 17 that changes threshold settings for the handoff process and the reselection process is realized on a computer by one or more programs. Alternatively, at least a part of it may be realized by hardware.

  DESCRIPTION OF SYMBOLS 10 ... Mobile phone, 11 ... Wireless communication part, 12 ... Operation part, 13 ... Audio | voice input / output part, 14 ... Display part, 15 ... Imaging part, 16 ... Memory | storage part, 17 ... Control part, 18 ... System bus, 161 ... Threshold change flag, 162... Location registration control flag, 170.

Claims (10)

A communication unit capable of wireless communication with a plurality of base stations;
A control unit having handoff processing means for causing the communication unit to perform handoff from a standby base station waiting in the communication unit to other neighboring base stations,
The controller is
The wireless terminal device, wherein the handoff is restricted when emergency information is received based on broadcast information from a base station waiting in the communication unit. The radio terminal apparatus according to claim 1, wherein the control unit regulates the handoff by regulating a change in position registration from the standby base station to the other base station. The emergency information is
The wireless terminal device according to claim 1, wherein the wireless terminal device is broadcast information designated by the broadcast information. The broadcast information is
The wireless terminal apparatus according to claim 3, wherein the wireless terminal apparatus is received in a broadcast slot which is a reception time slot of a paging channel established by the broadcast information. The emergency information is
The wireless terminal device according to claim 3 or 4, wherein the wireless terminal device is specified in broadcast information received in a standby slot in cases other than emergency information based on the broadcast information. The handoff processing means includes
When the signal strength from another base station is better than the signal strength from the standby base station, and the difference exceeds a predetermined threshold, the handoff process is controlled,
The controller is
The wireless communication apparatus according to claim 1, wherein when the emergency information is received, the predetermined threshold value is changed to be increased. The controller is
The wireless terminal apparatus according to claim 1, wherein when the emergency information is no longer received based on broadcast information from the base station, the handoff restriction is canceled. The controller is
When the emergency information is received, a timer for restricting the location registration is set before attempting location registration, and the restriction on the change of the location registration is released in response to detection of a timeout of the timer. Item 3. The wireless terminal device according to Item 2. The wireless terminal apparatus according to claim 8, wherein the timer is determined by a random number. A handoff control method in a wireless terminal device including a communication unit capable of wireless communication with a plurality of base stations,
From the standby base station waiting in the communication unit to other base stations in the vicinity, causing the communication unit to perform handoff,
Receiving broadcast information from a base station waiting in the communication unit;
Receiving emergency information based on the broadcast information;
A step of restricting the handoff when the emergency information is received.

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