JP2004201118A - Mobile communication terminal, radio zone shifting method and mobile communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mobile communication terminal for inexpensively realizing a reduction in location registration traffic near the boundary of a location registration area. <P>SOLUTION: This mobile communication terminal is provided with a receiving level measuring part 12 for measuring receiving levels of control signals transmitted from a plurality of radio base stations, a radio zone shift determining part 13 for shifting a radio zone when a radio zone shifting condition is established about the measured receiving level, and a location registration determining part 16 for performing a location registration request on the basis of location registration areas of a shifting source and a shifting destination in shifting the radio zone. The radio zone shift determining part 13 shifts the radio zone by a shifting condition different from a normal shifting condition when location registration is performed at the time of the last radio zone shifting and suppresses the location registration by suppressing radio zone shifting. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a mobile communication terminal, a wireless zone transfer method, and a mobile communication system, and more particularly, to a mobile communication system in which a large number of wireless zones are formed and a mobile communication terminal transfers between these wireless zones. Regarding improvement.
[0002]
2. Description of the Related Art In a mobile communication system employing a small zone system, there has been a problem that traffic near the boundary of a location registration area increases sharply. For example, when there is a mobile communication terminal that stays near the boundary of the location registration area, the mobile communication terminal repeatedly traverses the location registration area, and the location registration by the mobile communication terminal is frequently performed. there were. In such a case, the location registration traffic near the boundary of the location registration area will increase sharply.
[0003]
Further, the call request signal and the position registration request signal of the mobile communication terminal are transmitted by random access through the same uplink control channel. Therefore, there is a problem that control signal traffic increases near the boundary of the location registration area and the signal collision rate increases.
[0004]
A conventional mobile communication system that attempts to solve such a problem is disclosed in, for example, Patent Document 1. In this mobile communication system, when a mobile communication terminal enters a completely new location registration area, it requests location registration, and when it enters a location registration area where location registration has been performed in the past, a location registration request is made. Absent. Therefore, even when the mobile communication terminal moves near the boundary of the location registration area, the traffic of the control signal for location registration does not increase, and congestion of the wireless channel can be prevented. Further, when a call request is issued to the mobile communication terminal, a call is made from each of the latest and past radio base stations in the location registration area satisfying a predetermined condition.
[0005]
[Patent Document 1]
JP-A-8-172662 ([0051], FIGS. 4 to 6)
[0006]
[Problems to be solved by the invention]
The mobile communication system described in Patent Literature 1 provides a mobile communication system in which both a mobile communication terminal and an exchange store a location registration area in which the mobile communication terminal has performed location registration in the past. This is a system for reducing location registration requests by terminals.
[0007]
For this reason, this mobile communication system cannot be realized using conventional infrastructure equipment including an exchange, and it is necessary to improve these infrastructure equipment. However, in general, a large number of infrastructure facilities such as exchanges are installed nationwide, and improvement thereof requires a great deal of cost. For this reason, there was a problem that a great deal of cost was required to realize the mobile communication system described in Patent Document 1.
[0008]
The present invention has been made in view of the above circumstances, and has as its object to provide a mobile communication terminal capable of reducing location registration traffic near the boundary of a location registration area. It is another object of the present invention to provide a wireless zone transfer method and a mobile communication system capable of reducing location registration traffic at low cost.
[0009]
SUMMARY OF THE INVENTION A mobile communication terminal according to the present invention comprises: a receiving level measuring means for measuring a receiving level of a control signal transmitted from a plurality of radio base stations; A wireless zone shift unit that shifts the wireless zone when the shift condition is satisfied; and a position registering unit that issues a position registration request based on the source and destination position registration area information when shifting the wireless zone. When the location registration is performed at the time of the last wireless zone shift, the wireless zone shift means is configured to shift the wireless zone under a shift condition different from a normal time.
[0010]
A wireless zone transition method according to the present invention includes a reception level measuring step of measuring a reception level of a control signal transmitted from a plurality of wireless base stations, and a wireless zone transition condition when a wireless zone transition condition is satisfied for the measured reception level. And a location registration step of performing a location registration request based on the location registration area information of the migration source and the migration destination when the wireless zone is migrated. When the location registration is performed at the time of the shift to the wireless zone, the wireless zone is shifted under the shift condition different from the normal time.
[0011]
Further, the mobile communication system according to the present invention, each of which forms a wireless zone, and a number of wireless base stations that broadcast location registration area information, performs location registration by receiving location registration area information, A mobile communication system comprising a mobile communication terminal performing wireless communication, wherein the mobile communication terminal measures reception levels of control signals transmitted from a plurality of wireless base stations, and Wireless zone shifting means for shifting the wireless zone when the wireless zone shifting condition is satisfied for the reception level, and when shifting the wireless zone, issuing a location registration request based on the location registration area information of the migration source and the migration destination. A location registration unit, wherein when the location registration is performed at the time of the last wireless zone transition, the wireless zone transition unit performs wireless communications under a transition condition different from a normal time. Configured to migrate over emissions.
[0012]
With such a configuration, when the position registration is performed at the time of the last wireless zone shift, the subsequent shift of the wireless zone is suppressed, and the position registration is suppressed. Therefore, it is possible to suppress an increase in location registration traffic due to frequent repetition of location registration.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiment 1 FIG.
2. Description of the Related Art In a wireless communication system using a mobile communication terminal such as a mobile phone or a PHS, a small zone system (cellular system) in which an entire service area is divided into a large number of wireless zones is employed. Each of these wireless zones is formed by a wireless base station.
[0014]
Each radio base station transmits a control signal periodically. These control signals are called broadcast channels. The mobile communication terminal receives a broadcast channel from each wireless base station, and determines a wireless zone in which the mobile communication terminal is located based on the reception level. That is, the reception levels of a plurality of radio base stations are compared, and it is determined that the mobile station is in the radio zone of the radio base station that has obtained the maximum reception level.
[0015]
In such a small-zone wireless communication system, a mobile communication terminal cannot be accommodated in a specific switching center. For this reason, in order to be able to receive a call at the mobile communication terminal, it is necessary to constantly track and register the position of each mobile communication terminal in the upper device station of the wireless base station. This registration procedure is called location registration. Further, an area managed by a higher-level equipment station of the wireless base station and serving as a unit of location registration is called a location registration area.
[0016]
Each wireless zone can be a single location registration area, but in this case, it is necessary to perform location registration each time the mobile communication terminal moves between wireless zones. Therefore, there is a problem that the number of position registrations increases as the wireless zone becomes smaller, and the traffic of control signals for position registration increases.
[0017]
For this reason, in a general mobile communication system, a plurality of adjacent wireless zones are integrated into one location registration area, and the mobile communication terminal performs location registration each time it moves between location registration areas. . That is, when the mobile communication terminal moves between wireless zones belonging to the same location registration area, location registration is not performed. When the mobile communication terminal moves between wireless zones belonging to different location registration areas, location registration is performed.
[0018]
FIG. 1 is a block diagram showing a schematic configuration of a mobile communication system to which the present invention is applied. This mobile communication system includes a mobile communication terminal 1, a base station (BS) 2, a radio network controller 3, and a mobile switching center 4.
[0019]
Each wireless base station 2 is installed at a predetermined distance from each other, each forms a wireless zone 7, and transmits and receives wireless signals to and from the mobile communication terminal 1 in the corresponding wireless zone 7. . Note that the actual wireless zone 7 is formed so as to partially overlap each other between adjacent zones, but is simplified in FIG. 1 for convenience of explanation.
[0020]
Each radio network controller 3 is connected to a plurality of radio base stations 2 arranged adjacent to each other, and controls communication of each radio base station 2. The radio base stations 2 accommodated in the same radio network controller 3 belong to the same location registration area 8. That is, the wireless zones 7 are integrated for each wireless network control station 3 to form one location registration area 8.
[0021]
The mobile communication switching center 4 is connected to a plurality of radio network controllers 3 and controls connection between each radio network controller 3 and the public network 6. The mobile communication switching center 4 includes a location registration information storage unit 5, and stores and holds a location registration area registered by each mobile communication terminal 1. The database of the location registration area for each mobile communication terminal 1 held in the location registration information storage unit 5 is called a location register.
[0022]
The mobile communication terminal 1 monitors the broadcast channel transmitted from each wireless base station 2, determines the wireless zone 7 in which the mobile communication terminal 1 is located based on these reception levels, and if the reception level changes, The transfer of the wireless zone 7 is performed. The signal reception level from each wireless base station 2 changes due to the movement of the mobile communication terminal 1 and fluctuations in the surrounding radio wave environment. For example, when the mobile communication terminal 1 moves between the wireless zones 7, the wireless base station 2 from which the maximum reception level is obtained changes. The mobile communication terminal 1 shifts to the wireless zone 7 by detecting the change in the reception level.
[0023]
The broadcast channel transmitted from each wireless base station 2 includes a location registration area code, which is identification information of the location registration area 8, and the wireless base stations 2 belonging to the same location registration area 8 have the same location registration area. Informing the code.
[0024]
The mobile communication terminal 1 performs location registration based on the location registration area code when shifting to the wireless zone 7. The mobile communication terminal 1 extracts the location registration area code from the broadcast channel, and determines whether the location registration area 8 of the destination wireless zone 7 is the same as the existing location registration area 8. As a result, if the transition of the wireless zone 7 is a transition between different location registration areas 8, a location registration request is transmitted to the wireless base station 2. With this position registration request, the location register in the position registration information storage unit 5 is updated.
[0025]
The incoming call at the mobile communication terminal 1 is performed by calling all the wireless base stations 2 in the location registration area 8 where the mobile communication terminal 1 is located at once. That is, when calling the mobile communication terminal 1, the mobile communication switching center 4 determines the location registration area 8 of the mobile communication terminal 1 based on the location registration information storage unit 5 and stores it in the location registration area 8. A paging signal is transmitted to each of the radio base stations 2 to which the radio base station 2 belongs via the radio network controller 3, and the radio base stations 2 make a call at the same time.
[0026]
FIG. 2 is a block diagram showing one configuration example of a main part of the mobile communication terminal of FIG. The mobile communication terminal 1 includes an antenna 10, a wireless transmission / reception unit 11, a reception level measurement unit 12, a wireless zone shift determination unit 13, a wireless zone shift information storage unit 14, a location registration area code extraction unit 15, and a location registration determination unit 16. And a location registration information storage unit 17.
[0027]
The wireless transmission / reception unit 11 transmits / receives a wireless signal to / from the wireless base station 2 via the antenna 10. The reception level measurement unit 12 is a unit that measures the reception power of the broadcast channel received from the wireless base station 2. The reception level measurement unit 12 measures the reception level of each broadcast channel receivable by the wireless transmission / reception unit 11 and outputs the measurement result to the wireless zone shift determination unit 13.
[0028]
The wireless zone shift determination unit 13 determines whether or not the wireless zone needs to be shifted based on the reception level. This determination is made based on whether a predetermined transition condition is satisfied. In the present embodiment, when the reception level from another wireless base station 2 exceeds the reception level from the wireless base station 2 forming the wireless zone 7 in the service area beyond a predetermined determination time, The transition to the wireless zone 7 formed by the other wireless base station 2 is performed. Details of the transition condition will be described later.
[0029]
The transfer of the wireless zone is performed by changing the channel information in the wireless transmission / reception unit 11 to the channel information of the wireless base station 2 in the wireless zone 7 of the transfer destination. After that, the mobile communication terminal 1 Radio signals can be transmitted to and received from the base station 2.
[0030]
When the wireless zone 7 is transferred, the identification information of the transfer source wireless zone 7 is stored in the wireless zone transfer information storage unit 14. Here, information on the control channel of the wireless base station 2 forming the transfer source wireless zone 7, for example, a scrambling code or a PDC (Personal Digital Cellular) in the case of W-CDMA (Wide-band Code Division Multiple Access). If the method is used, the frequency is stored.
[0031]
The location registration area code extraction unit 15 extracts the location registration area code from the broadcast channel received from the wireless base station 2 and outputs the location registration area code to the location registration determination unit 16. When the wireless zone shift is performed by the wireless zone shift determining unit 13, the location registration determining unit 16 determines that the wireless zone 7 of the transfer source (current wireless zone 7) and the wireless zone 7 of the transfer destination are the same. It is determined whether or not it belongs to the position registration area 8. This determination is made by comparing the location registration area codes.
[0032]
The location registration information storage unit 17 stores a location registration area code of the wireless zone 7 in the area where the user is located. The location registration determination unit 16 compares the location registration area code with the location registration area code extracted from the broadcast channel of the destination wireless base station 2. As a result, if they match, a position registration request is not made, and if they do not match, a position registration request is made. The location registration request is performed by the wireless transmission / reception unit 11 transmitting a location registration request signal to the wireless base station 2.
[0033]
FIG. 3 is a diagram illustrating an example of the transition determination in the wireless zone transition determination unit 13 of FIG. In this figure, the reception levels L1 and L2 from the two radio base stations 2 measured by the reception level measurement unit 12 are shown with time on the horizontal axis and the reception level on the vertical axis. The reception level L1 is a reception level from the wireless base station 2 of the wireless zone 7 in which the mobile station 7 is located, and the reception level L2 is a reception level from the wireless base station 2 of another wireless zone 7 adjacent to the wireless zone 7 concerned. It is.
[0034]
The first reception level is L1> L2, and the reception level L1 from the wireless base station 2 in the wireless zone 7 in which the mobile terminal is located is higher. However, at time t0, the reception levels L1 and L2 are reversed and L2> L1, and the reception level L2 from the other radio base station 2 is higher.
[0035]
When the state of L2> L1 where the reception level is reversed is maintained beyond the determination time T1 or T2, the wireless zone shift determination unit 13 forms the other wireless base station 2 that has obtained the high reception level L2. To the wireless zone 7 to be performed.
[0036]
The second determination time T2 is longer than the first determination time T1, and the first determination time T1 is normally used. On the other hand, the mobile communication terminal 1 may frequently repeat the location registration request. In some cases, the second determination time T2 is used. More specifically, when the location registration is performed at the time of the last wireless zone transfer and the transfer source of the wireless zone transfer matches the transfer destination of the new wireless zone transfer, the second The determination time T2 is used.
[0037]
Whether or not the location registration was performed at the time of the last wireless zone shift can be determined by, for example, storing the time of the last location registration and the time of the last wireless zone shift, and comparing the two. . Alternatively, a flag that is set (reset) by location registration and reset (set) by wireless zone shift without location registration can be provided, and the flag can be used for discrimination.
[0038]
Whether or not the transfer source of the last wireless zone transfer matches the transfer destination of the new wireless zone transfer is determined by the channel information of the transfer destination of the new wireless zone transfer received by the wireless transmitting / receiving unit 11 and the wireless zone transfer. The determination is made by comparing the channel information stored in the transition information storage unit 14 with the channel information.
[0039]
The case where the second determination time T2 is used is a case where an attempt is made to shift to a wireless zone in which the location registration area 8 reciprocates between two different wireless zones. When the mobile communication terminal 1 stays near the boundary of the location registration area 8, it is considered that reciprocation between the same two location registration areas 8 is repeated. For this reason, by making the determination conditions for the wireless zone shift more strict, the number of shifts to the wireless zone 7 can be reduced, and the number of location registrations can also be reduced.
[0040]
Steps S101 to S109 in FIGS. 4 and 5 are flowcharts showing an example of the operation of the mobile communication terminal 1 in FIG. If the state in which the reception level L2 from another wireless base station 2 exceeds the reception level L1 from the existing wireless base station 2 (L2> L1) does not exceed the first determination time T1, the mobile station shifts to the wireless zone. Is not performed (step S101).
[0041]
When the state of L2> L1 is maintained for more than the first determination time T1, if the location registration has not been performed at the time of the last wireless zone shift, the wireless zone shift determining unit 13 shifts the wireless zone ( Steps S102 and S105). If the transfer source of the last wireless zone transfer does not match the transfer destination of the new wireless zone transfer, the wireless zone transfer is performed (steps S103 and S105). On the other hand, if the location registration is performed at the time of the last zone transfer and the transfer source of the last wireless zone transfer and the transfer destination of the new wireless zone transfer match, L2> L1 over the second determination time T2. If the state is not maintained, the wireless zone is not shifted (steps S104 and S105).
[0042]
When the transfer of the wireless zone is performed in step S105, the wireless zone transfer determination unit 13 stores the identification information of the transfer source wireless zone in the wireless zone transfer information storage unit 14 (step S106).
[0043]
In addition, with the shift to the wireless zone, if necessary, the position registration determination unit 16 issues a position registration request (steps S107 to S109). That is, the location registration area codes of the migration source and destination wireless zones 7 in the new wireless zone migration are compared, and if they do not match, a location registration request signal is transmitted (step S108), and the new location registration is performed. The area code is stored in the location registration information storage unit 17 (Step S109). When the second determination time T2 is used, position registration (steps S108 and S109) is always performed.
[0044]
According to the present embodiment, when location registration is performed at the time of the last wireless zone shift, mobile communication terminal 1 shifts the wireless zone under a shift condition different from the normal time. In particular, when the wireless zone is shifted by maintaining the inverted state of the reception level beyond the predetermined determination time, the location registration is performed at the last wireless zone shift, and the shift to the last wireless zone shift is performed. If the source and the new wireless zone transfer destination match, the determination time is set to be longer than the normal time. In other words, the transition determination condition is strict and the transition to the wireless zone is suppressed, and the location registration is suppressed.
[0045]
Therefore, the mobile communication terminal 1 repeats position registration while staying near the boundary of the position registration area 8, thereby suppressing a sudden increase in position registration traffic near the boundary of the position registration area. Moreover, the suppression of the location registration can be realized by improving only the mobile communication terminal 1. That is, it can be realized economically and can be applied to a mobile communication system using conventional infrastructure equipment.
[0046]
Embodiment 2 FIG.
In the first embodiment, an example has been described in which the mobile communication terminal performing the wireless zone migration uses the determination time as the migration condition, and the migration condition is made different. On the other hand, in the second embodiment, a description will be given of a case of a mobile communication terminal that shifts a wireless zone using a reception level difference as a shift condition.
[0047]
FIG. 6 is a diagram illustrating another example of the transition determination in the wireless zone transition determination unit 13 of FIG. In this figure, the reception levels L1 and L2 from the two radio base stations 2 measured by the reception level measurement unit 12 are shown with time on the horizontal axis and the reception level on the vertical axis. The reception level L1 is a reception level from the wireless base station 2 of the wireless zone 7 in which the mobile station 7 is located, and the reception level L2 is a reception level from the wireless base station 2 of another wireless zone 7 adjacent to the wireless zone 7 concerned. It is.
[0048]
The first reception level is L1> L2, and the reception level L1 from the wireless base station 2 in the wireless zone 7 in which the mobile terminal is located is higher. However, at time t0, the reception levels L1 and L2 are reversed and L2> L1, and the reception level L2 from the other radio base station 2 is higher.
[0049]
When the level difference of the inverted reception level exceeds the determination level difference LD1 or LD2, the wireless zone shift determination unit 13 proceeds to the wireless zone 7 formed by the other wireless base station 2 from which the reception level L2 was obtained. Migrate. That is, when there is a change in the reception level difference exceeding a predetermined hysteresis level, the wireless zone is shifted.
[0050]
The second determination level difference LD2 is a reception level difference larger than the first determination level difference LD1, and the first determination level difference LD1 is normally used, while the mobile communication terminal 1 issues a location registration request. If there is a possibility of frequent repetition, the second determination level difference LD2 is used. More specifically, when the location registration is performed at the time of the last wireless zone transfer and the transfer source of the wireless zone transfer matches the transfer destination of the new wireless zone transfer, the second Is used.
[0051]
The case where the second determination level difference LD2 is used is a case where an attempt is made to transfer to a wireless zone in which the location registration area 8 reciprocates between two different wireless zones. When the mobile communication terminal 1 stays near the boundary of the location registration area 8, it is considered that reciprocation between the same two location registration areas 8 is repeated. For this reason, by making the determination conditions for the wireless zone shift more strict, the number of shifts to the wireless zone 7 can be reduced, and the number of location registrations can also be reduced.
[0052]
Steps S201 to S204 in FIG. 7 are flowcharts illustrating another example of the operation of the mobile communication terminal 1 in FIG. Note that, similarly to steps S101 to S104 in FIG. 4, steps S105 to S109 in FIG. 5 are executed following steps S201 to S204.
[0053]
If the reception level L2 from the other wireless base station 2 exceeds the reception level L1 from the existing wireless base station 2 and the level difference does not exceed the first determination level difference LD1, the transition to the wireless zone is made. Not performed (step S201).
[0054]
When the level difference between the reception levels L2 and L1 exceeds the first determination level difference LD1, if the location registration has not been performed at the time of the last wireless zone shift, the wireless zone shift determining unit 13 determines the shift of the wireless zone. Perform (step S202). If the transfer source of the last wireless zone transfer does not match the transfer destination of the new wireless zone transfer, the wireless zone transfer is performed (step S203). On the other hand, if location registration is performed at the time of the last zone transfer and the transfer source of the last wireless zone transfer and the transfer destination of the new wireless zone transfer match, the level difference between the reception levels L2 and L1 becomes the second. If the difference does not exceed the determination level difference LD2, the wireless zone is not shifted (step S204).
[0055]
According to the present embodiment, when the reception level is reversed and the wireless zone is shifted by the level difference exceeding a predetermined determination level difference, the location registration is performed at the last wireless zone shift, and If the transfer source of the transfer to the new wireless zone matches the transfer destination of the new wireless zone transfer, the determination level difference is set to a value larger than the normal time. In other words, the transition determination condition is strict and the transition to the wireless zone is suppressed, and the location registration is suppressed.
[0056]
Embodiment 3 FIG.
In the first embodiment, an example has been described in which the determination time as the transition condition is made different, and in the second embodiment, the wireless zone migration is suppressed by making the determination level difference which is the migration condition different. . On the other hand, in the third embodiment, an example will be described in which the transfer of the wireless zone is prohibited for a certain period.
[0057]
FIG. 8 is a diagram illustrating another example of the transition determination in the wireless zone transition determination unit 13 of FIG. In this figure, the reception levels L1 and L2 from the two radio base stations 2 measured by the reception level measurement unit 12 are shown with time on the horizontal axis and the reception level on the vertical axis. The reception level L1 is a reception level from the wireless base station 2 of the wireless zone 7 in which the mobile station 7 is located, and the reception level L2 is a reception level from the wireless base station 2 of another wireless zone 7 adjacent to the wireless zone 7 concerned. It is.
[0058]
The first reception level is L1> L2, and the reception level L1 from the wireless base station 2 in the wireless zone 7 in which the mobile terminal is located is higher. However, at time t0, the reception levels L1 and L2 are reversed and L2> L1, and the reception level L2 from the other radio base station 2 is higher. Therefore, it is assumed that the transition condition of the wireless zone, for example, the condition of the determination time or the determination level difference is satisfied at the time t3, and the wireless zone shift determination unit 13 has performed the wireless zone transition. In addition, if necessary with the shift of the wireless zone, location registration is also executed.
[0059]
If the location registration is not executed during the transfer of the wireless zone, if the transfer condition is satisfied again thereafter, the wireless zone transfer determination unit 13 transfers the wireless zone again. However, when the location registration is executed at the time of shifting to the wireless zone at time t3, the shifting of the wireless zone is prohibited until the predetermined shift prohibition time T3 has elapsed. That is, the wireless zone shift determination unit 13 does not shift the wireless zone unless the time t4 is reached even if the shift condition is satisfied.
[0060]
If the transition condition is satisfied again during the transition prohibition time T3, it is considered that the position registration is frequently repeated. For this reason, by making the determination conditions for the wireless zone shift more strict, the number of shifts to the wireless zone 7 can be reduced, and the number of location registrations can also be reduced.
[0061]
Steps S301 to S304 in FIG. 9 are flowcharts illustrating another example of the operation of the mobile communication terminal 1 in FIG. First, based on the reception level from each wireless base station 2, a process of shifting the wireless zone is performed (step S301). That is, if the predetermined transition condition is satisfied, the wireless zone shift determining unit 13 shifts the wireless zone. Further, at the time of transfer to the wireless zone, a position registration process is performed based on the transfer source and transfer destination position registration areas (step S302). That is, the location registration area codes before and after the transition are compared, and if they do not match, the location registration determination unit 16 issues a location registration request.
[0062]
If the location registration has not been performed in step S302, the process ends (step S303). Thereafter, if the wireless zone shift condition is satisfied, the wireless zone shift is immediately performed in step S301. On the other hand, if the location registration has been performed, the process waits until the shift prohibition time T3 has elapsed, during which time the shift of the wireless zone is not performed (step S304).
[0063]
According to the present embodiment, when the wireless zone is shifted, if the location registration is performed, the shift of the wireless zone is prohibited for a predetermined period. Therefore, the mobile communication terminal 1 repeats position registration while staying near the boundary of the position registration area 8, thereby suppressing a sudden increase in position registration traffic near the boundary of the position registration area. Moreover, the suppression of the location registration can be realized by improving only the mobile communication terminal 1. That is, it can be realized economically and can be applied to a mobile communication system using conventional infrastructure equipment.
[0064]
【The invention's effect】
According to the present invention, when location registration is performed at the time of the last wireless zone transfer, the subsequent wireless zone transfer conditions are made different from the normal transfer conditions, thereby suppressing wireless zone transfer. Therefore, it is possible to reduce the position registration traffic near the boundary of the position registration area. In addition, it is possible to reduce such location registration traffic at low cost.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a schematic configuration of a mobile communication system to which the present invention is applied.
FIG. 2 is a block diagram showing a configuration example of a main part of the mobile communication terminal 1 of FIG.
FIG. 3 is a diagram illustrating an example of a transition determination in a wireless zone transition determination unit 13 in FIG. 2;
4 is a flowchart illustrating an example of an operation of the mobile communication terminal 1 in FIG.
FIG. 5 is a flowchart illustrating an example of an operation performed subsequently to FIG. 4;
FIG. 6 is a diagram showing another example of the transition determination in the wireless zone transition determination unit 13 of FIG. 2 (Embodiment 2).
FIG. 7 is a flowchart showing another example of the operation of the mobile communication terminal 1 of FIG.
FIG. 8 is a diagram showing another example of the transition determination in the wireless zone transition determination unit 13 of FIG. 2 (Embodiment 3).
9 is a flowchart illustrating another example of the operation of the mobile communication terminal 1 in FIG.
[Explanation of symbols]
1 mobile communication terminal, 2 radio base station, 3 radio channel control station,
4 mobile communication switching office, 5 location registration information storage unit, 6 public network,
7 wireless zones, 8 location registration areas, 10 antennas, 11 wireless transceivers,
12 reception level measurement unit, 13 wireless zone shift determination unit,
14 wireless zone shift information storage unit, 15 location registration area code extraction unit,
16 position registration judgment section, 17 position registration information storage section, L1, L2 reception level,
LD1, LD2 judgment level difference, T1, T2 judgment time, T3 shift prohibition time

Claims (6)

Reception level measurement means for measuring reception levels of control signals transmitted from a plurality of radio base stations,
Wireless zone shift means for shifting the wireless zone when the wireless zone shift condition is satisfied for the measured reception level,
When migrating the wireless zone, based on the location registration area information of the migration source and migration destination, comprising a location registration means for making a location registration request,
The mobile communication terminal according to claim 1, wherein the wireless zone shift means shifts the wireless zone under a shift condition different from a normal time when the location registration is performed at the time of the last wireless zone shift. When migrating the wireless zone, comprises a wireless zone information storage means for storing identification information of the wireless zone of the migration source,
The above-mentioned wireless zone shift means, when the reception level from another wireless base station exceeds the reception level from the wireless base station forming the existing wireless zone for more than a predetermined determination time, Shift to the wireless zone formed by the wireless base station of
The determination time is set when the position registration is performed at the time of the last wireless zone shift, and the identification information stored in the wireless zone information storage unit matches the identification information of the new wireless zone to be shifted. The mobile communication terminal according to claim 1, wherein the time is longer than a normal time. When migrating the wireless zone, comprises a wireless zone information storage means for storing identification information of the wireless zone of the migration source,
The wireless zone shift means, when the received level from another wireless base station exceeds the received level from the wireless base station forming the wireless zone in the service area by exceeding a predetermined determination level difference, Shift to the wireless zone formed by other wireless base stations,
The determination level difference is obtained when the location registration is performed at the time of the last wireless zone shift, and the identification information stored in the wireless zone information storage unit matches the identification information of the new wireless zone to be shifted to. 2. The mobile communication terminal according to claim 1, wherein the level difference is larger than a normal level. 2. The mobile communication terminal according to claim 1, wherein when the location registration is performed at the time of the last wireless zone shift, the wireless zone shift unit does not shift the wireless zone until a predetermined time has elapsed. . A reception level measuring step of measuring a reception level of a control signal transmitted from a plurality of radio base stations,
A wireless zone shift step of shifting the wireless zone when the wireless zone shift condition is satisfied for the measured reception level;
When migrating the wireless zone, based on the location registration area information of the migration source and migration destination, comprising a location registration step of making a location registration request,
In the wireless zone transfer step, when the location registration is performed at the time of the last wireless zone transfer, the wireless zone is transferred under a transfer condition different from a normal time. Each mobile base station forms a wireless zone and broadcasts location registration area information, and a mobile communication terminal that receives location registration area information, performs location registration, and performs wireless communication with the wireless base station. In body communication systems,
A mobile communication terminal, receiving level measuring means for measuring a receiving level of a control signal transmitted from a plurality of radio base stations,
Wireless zone shift means for shifting the wireless zone when the wireless zone shift condition is satisfied for the measured reception level,
When migrating the wireless zone, based on the location registration area information of the migration source and migration destination, comprising a location registration means for making a location registration request,
A mobile communication system, wherein the wireless zone shift means shifts a wireless zone under a shift condition different from a normal time when a position registration is performed at the time of a last wireless zone shift.

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