JP2006157217A - Apparatus for cell reselection, mobile communication terminal, method for cell reselection, program and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress undue repetition (fluttering) of cell reselect operation in a code division multiple access system mobile communication terminal. <P>SOLUTION: An apparatus for cell reselection comprises means 6 and 7 for reselecting the cell of its own station when cell reselect conditions are satisfied, a means 11 for counting the number of times when the cell of its own station in the past becomes the cell of its own station anew by reselect operation, a means 10 for clocking a predetermined time, a means 7 for deciding that cell reselect operation is fluttering when the count of the count means 11 reaches a predetermined number before the clocking operation is completed, and the means 7 for suppressing cell reselect operation when the fluttering decision means decides the occurrence of fluttering. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cell reselection device provided in a mobile communication terminal device, a mobile communication terminal device including the cell reselection device, a cell reselection method in the mobile communication terminal device, a program thereof, and a recording medium.

  For example, a mobile communication terminal device such as a mobile phone selects a cell serving as a local cell from cells formed by each of a plurality of wireless base stations, and transmits a radio signal to and from the selected local cell. Communicate by sending and receiving.

  Here, a mobile communication terminal apparatus compatible with the CDMA scheme (CDMA: Code Division Multiple Access = Code Division Multiple Access scheme) is, for example, a radio that is transmitted from a radio base station that forms its own cell and neighboring cells during standby. It is possible to periodically measure the signal reception strength and quality, perform cell reselection autonomously according to the measurement result, and switch the local cell.

  At the time of this cell reselection, the specification of the neighboring cells to be measured and the parameter group for defining the cell reselection criteria are defined based on the system information broadcast from the radio base station of the own cell. .

  Cell reselection is a state in which any measurement value in the measurement value (Qn [dB]) of the neighboring cell exceeds the measurement value (Qs [dB]) of the local station cell (a state where Qn> Qs). Is performed when it continues for a certain period of time (Trselection [sec]), and the cell with the best measurement result at that time is set as the local cell.

  By the way, when the mobile communication terminal apparatus is located near the boundary between two cells, the measured values of both cells in the mobile communication terminal apparatus are close to each other as shown in FIG. 5, for example.

  That is, FIG. 5 shows that the measurement value of cell A (solid line) and the measurement value of cell B (one-dot chain line) repeatedly increase or decrease from each other. A state in which the state of becoming a local cell is excessively repeated, that is, a state in which a so-called flutter occurs is shown.

  In this way, if the measurement values of a plurality of cells continue to be close to each other, the mobile communication terminal apparatus that performs the cell reselection operation as described above causes a phenomenon in which cell reselection is excessively repeated (battery). ) Occurs, the power consumption of the mobile communication terminal device increases, resulting in a decrease in waiting time.

  In view of such circumstances, Patent Document 1 discloses a technique for suppressing the occurrence of fluttering.

  As shown in FIG. 6, the mobile communication terminal apparatus 1000 of Patent Document 1 includes an antenna 103, a receiving circuit 104, a transmitting circuit 113, and a reception level (electric field strength) of a received radio wave of a serving cell (own cell). The field strength measurement unit 106 for measuring the signal strength and the reception radio wave condition of the own cell deteriorates when the measurement result by the field strength measurement unit 106 falls below a predetermined threshold value for a predetermined number of times during a predetermined time. A CR instruction generation unit 107 that recognizes and generates a CR instruction (cell reselection instruction), a CR counter 110 that counts the number of times the CR instruction is generated, a zone transition restriction timer 111 that measures a predetermined time, a control circuit 102, , And is configured.

  The control circuit 102 shifts whenever it performs control to increment the count value of the CR counter 110 by “1” each time a CR instruction is generated by the CR instruction generation unit 107 and zone transfer processing (cell reselection processing). Control for storing the SC of the target cell in the history storage unit 109 of the memory 108, control for clearing the stored contents of the history storage unit 109 when a notification of expiration of a predetermined time is received from the zone transfer restriction timer 111, and zone transfer processing Control to perform.

  When the CR instruction is generated by the CR instruction generator 107, the control circuit 102 determines whether or not the count value of the CR counter 110 has reached a predetermined value. If the zone transfer restriction timer 111 is not activated, it is determined whether or not the zone transfer restriction timer 111 is activated. If it is activated, the SC of the cell to be migrated according to the CR instruction is stored in the history storage unit 109. It is determined whether or not it is stored. If it is not stored, the zone shift process is performed. If it is stored, the count value of the CR counter 110 is incremented without performing the zone shift process. On the other hand, if the zone transition restriction timer 111 is not activated, it is determined whether or not the SC of the transition target cell according to the CR instruction is stored in the history storage unit 109. If not stored, the zone transition process is performed. If it is stored, the count value of the CR counter 110 is incremented without performing the zone transfer process and the zone transfer restriction timer 111 is started.

  According to such a technique of Patent Document 1, the mobile communication terminal apparatus 1000 stores and retains a history of a cell that has existed before, and whether or not there is a migration target cell in the history when there is a CR instruction. If it is in the history, zone transition processing (cell reselection processing) is suppressed. That is, the occurrence of fluttering is suppressed.

  It should be noted that the number of CR instructions generated is counted, and if the CR instruction is generated after the count value reaches a predetermined number, the zone transfer process is performed regardless of the contents of the history. The degree of suppression can be adjusted as appropriate.

Further, a zone transition restriction timer 111 for measuring a predetermined time is provided. When a CR instruction is generated while the timer 11 is stopped, the timer 111 is started, and when the expiration of the predetermined time is counted by the timer 111, a history is recorded. Therefore, the degree of suppression of the zone transition process can be adjusted more suitably.
Japanese Patent Laid-Open No. 2003-70047 (FIGS. 5 and 6)

  However, in the case of the technique of Patent Document 1, when a CR instruction is generated after the count value of the CR counter 110 reaches a predetermined value, cell reselection processing is performed unconditionally. When there are too many, there exists a problem that the frequency of a cell reselection process cannot be reduced to the extent that it can be said that generation | occurrence | production of flapping was suppressed.

  That is, in the technique of Patent Document 1, although the frequency of the cell reselection process can be reduced, if the CR instruction is generated too frequently, the fluttering occurs, and thus the fluttering suppressing effect is achieved. That's not enough.

  The present invention has been made to solve the above-described problems, and a cell reselection device and mobile communication that can suppress repetition (flutter) of a cell reselection operation more favorably than the prior art. An object is to provide a terminal device, a cell reselection method, a program, and a recording medium.

  In order to solve the above-described problem, the cell reselection apparatus of the present invention reestablishes its own cell when the cell reselection condition is satisfied in the cell reselection apparatus provided in the code division multiple access mobile communication terminal apparatus. A cell reselection control means for performing a cell reselection operation to be selected; a counting means for counting the number of times that a cell previously set as the local station cell is newly set as the local station cell by the cell reselection operation; and counting a predetermined time A timing generation means, a fluctuation occurrence determination means for determining that a fluctuation of a cell reselection operation has occurred when a count value by the counting means reaches a predetermined number before the timing operation by the timing means expires, and It is characterized by comprising suppression control means for suppressing the cell reselection operation when it is determined by the flicker occurrence determining means that flicker has occurred.

  In the cell reselection device according to the present invention, when the flutter occurrence determination means determines that the flutter has occurred, the suppression control means corrects the cell reselection condition with a correction value to satisfy the condition. It is preferable to suppress the cell reselection operation by making it difficult.

  In the cell reselection device of the present invention, the suppression control unit increases the correction value of the cell reselection condition each time the flicker occurrence determination unit determines that the flutter has occurred, It is preferable to make it difficult to establish.

  In the cell reselection device of the present invention, when the timing operation by the timing unit expires before the count value by the counting unit reaches the predetermined number, the cell reselection condition added by the suppression control unit It is preferable to provide release control means for reducing the correction value and releasing the effect of suppressing the cell reselection operation.

  In the cell reselection device of the present invention, each time the correction value of the cell reselection condition is increased by the suppression control unit, the count value by the count unit is reset, while the time counting operation by the time measuring unit is performed. It is preferable to provide initialization means for restarting from the beginning.

  In the cell reselection device according to the present invention, each time the correction value of the cell reselection condition is increased by the suppression control unit and every time the correction value is decreased by the release control unit, the counting unit It is preferable to include initialization means for initializing the counting operation according to the above and the timing operation by the timing means.

  In the cell reselection device of the present invention, assuming that the received radio wave intensity of the local cell is Qs, the received radio wave intensity of the neighboring cells is Qn, and the correction value is R, the cell reselection condition is (Qn−R)> It is preferable that the Qs state is established when the second predetermined time is continued.

  In the cell reselection device of the present invention, the cell reselection device includes a local cell history storage unit that stores and holds a predetermined number of cell identification information that was previously set as the local cell, and the counting unit performs the cell reselection operation. Thus, it is preferable to count the number of times the identification information of the cell newly set as the own station cell matches the identification information stored and held in the own station cell history storage means.

  A mobile communication terminal apparatus according to the present invention is a code division multiple access system mobile communication terminal apparatus, comprising the cell reselection apparatus according to the present invention.

  The mobile communication terminal device of the present invention is preferably a mobile phone, for example.

  The cell reselection method of the present invention is a method for performing cell reselection in a code division multiple access mobile communication terminal apparatus, a condition establishment determination step for determining establishment of a cell reselection condition, and the condition establishment determination A cell reselection step for reselecting a local station cell when it is determined that a cell reselection condition is satisfied in the process, and a cell that has been previously set as the local station cell is newly determined by the cell reselection step. A counting step for counting the number of times, a timing step for timing a predetermined time, and a cell reselection operation when the count value in the counting step reaches a predetermined number before the timing operation by the timing step expires A flutter occurrence determining step for determining that flickering has occurred, and a suppressing step for suppressing a cell reselection operation when it is determined that flutter has occurred in the flutter occurrence determining step; I am characterized in that it comprises.

  In the cell reselection method of the present invention, in the suppression step, when it is determined that the flutter has occurred in the flutter generation determination step, the cell reselection condition is hardly corrected by correcting the cell reselection condition with a correction value. It is preferable to suppress the cell reselection operation.

  The program of the present invention is a computer-executable program, a condition establishment determination process for determining establishment of a cell reselection condition in a code division multiple access mobile communication terminal apparatus, and cell reselection in the condition establishment determination process When it is determined that the condition is satisfied, the cell reselection process for reselecting the local station cell and the number of times that the cell that has been previously set as the local station cell is newly set as the local cell by the cell reselection process are counted. When the count process, the time measurement process for measuring a predetermined time, and the count value of the count process reaches a predetermined number before the time measurement operation by the time measurement process expires, the cell reselection operation flickers. When the flicker occurrence determination process and the flicker occurrence determination process determine that the flicker has occurred, the suppression of suppressing the cell reselection operation is suppressed. It is characterized by executing processing and, the.

  In the program according to the present invention, in the suppression process, when it is determined that a flutter has occurred in the flutter generation determination process, the cell reselection condition is corrected with a correction value to make it difficult to satisfy the condition. It is preferable to suppress the cell reselection operation.

  The recording medium of the present invention is a computer-readable recording medium in which the program of the present invention is stored.

  According to the present invention, when the number of times that a cell that was previously set as a local station cell is newly set as the local station cell reaches a predetermined number within a predetermined time, it is determined that the cell reselection operation has fluttered. Since the occurrence determination means is provided, occurrence of flutter can be reliably determined. Furthermore, since the suppression control means for suppressing the cell reselection operation is provided when the flicker occurrence determination means determines that the flicker has occurred, the flicker can be reliably suppressed when the flicker occurs.

  Embodiments according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic diagram showing a mobile communication system 300 configured to include a mobile communication terminal apparatus 100 (FIG. 2) according to an embodiment of the present invention.

  The mobile communication system 300 employs a code division multiple access (CDMA) system, and as shown in FIG. 1, a mobile communication terminal apparatus (UE: User Equipment) 100 and a mobile communication terminal apparatus 100 And a radio base station (BTS: Base Transceiver Station) 200 that transmits / receives radio signals to / from.

  Here, the mobile communication terminal apparatus 100 is, for example, a mobile phone, but may be a PDA (Personal Digital Assistant) or other mobile communication terminal apparatus.

  FIG. 2 is a functional block diagram showing the mobile communication terminal apparatus 100 according to the embodiment of the present invention.

  A mobile communication terminal apparatus 100 shown in FIG. 2 is used in the mobile communication system 300 shown in FIG. 1, and includes an antenna 1, a reception circuit 2, a transmission circuit 3, an SC detection unit 4, a reception intensity / quality. Measurement unit 5, cell selection control unit (cell reselection control unit) 6, processing control unit (cell reselection control unit, flicker generation determination unit, suppression control unit, release control unit, initialization unit) 7, memory 8, a flutter monitoring timer (timer means) 10, and a flutter monitoring counter (count means) 11.

  Among these, the antenna 1 transmits and receives radio signals to and from one or a plurality of radio base stations 200 capable of transmitting and receiving radio signals among the plurality of radio base stations 200.

  The reception circuit 2 performs a predetermined process on the radio signal received by the antenna 1 and outputs the received signal after the process to the SC detection unit 4 and the reception intensity / quality measurement unit 5.

  The transmission circuit 3 transmits a radio signal to the radio base station 200 via the antenna 1.

  The SC detection unit 4, based on the received signal output from the receiving circuit 2, a first common pilot channel (P-CPICH: Primary-Common Pilot Channel) scrambling code (SC: Scrambling Code) for identifying a cell. ) Is detected, and the detected SC is notified to the processing control unit 7.

  The process control unit 7 transfers the SC notified from the SC detection unit 4 to the reception intensity / quality measurement unit 5.

  The reception strength / quality measurement unit 5 periodically measures the reception strength / quality of its own cell / neighboring cell based on the reception signal of the cell corresponding to the SC notified from the processing control unit 7, and obtains the measured value. The cell selection control unit 6 is notified.

  The cell selection control unit 6 instructs the processing control unit 7 to execute cell reselection according to the cell reselection criteria based on the measurement value notified from the reception intensity / quality measurement unit 5. The cell selection control unit 6 instructs the processing control unit 7 to execute cell selection based on the measurement value notified from the reception intensity / quality measurement unit 5 when the power is turned on.

  The processing control unit 7 performs cell selection / cell reselection in response to an instruction from the cell selection control unit 6, transmits / receives message / data to / from each functional block, and accesses the memory 8.

  The memory 8 includes an SC history storage unit (own cell history storage means) 9 that stores and holds the history of the SC as identification information of the previous own cell. The SC history is written in the SC history storage unit 9 by the processing control unit 7. The SC history storage unit 9 can store N SCs (N is a positive integer of 2 or more) as an upper limit number.

  The flutter monitoring timer 10 is a timer used to determine the occurrence of flutter, and operates under the control of the processing control unit 7. The flutter monitoring timer 10 starts a timing operation when activated in response to a command from the processing control unit 7, ends the timing operation when the timing of the predetermined time T1 expires, and indicates that the timing has expired. Notify

  Note that the predetermined time T is set to be longer than a certain time (Trection) used for determination of cell reselection.

  The flutter monitoring counter 11 is a counter that is used to determine the occurrence of flutter, and operates under the control of the processing control unit 7.

  Next, an outline of main operations of the mobile communication terminal apparatus 100 will be described.

  The process control unit 7 stores the SC (identification information) of a cell newly set as a local cell in the SC history storage unit 9 as a history each time cell reselection is performed, and refers to the SC history storage unit 9. By doing so, it is possible to recognize up to N cells that were previously set as the own cell. Hereinafter, the SC history stored in the SC history storage unit 9 is referred to as SC history.

  In addition, the number of times that a cell in the SC history is reselected during the operation of the flutter monitoring timer 10 (identification information of a cell newly set as a local cell by the cell reselection operation is stored and held in the SC history storage unit 9. When the count value is equal to or greater than a predetermined number (THRESH), the processing control unit 7 determines that the flicker has occurred. .

  When it is determined by the processing control unit 7 that a flutter has occurred, the cell reselection control unit 6 performs a correction for subtracting the correction value R [dB] from the measured value Qn [dB] of the received radio wave intensity of the neighboring cells. Then, the corrected measured value Qn is compared with the measured value Qs [dB] of the received radio wave intensity of the own station cell to determine whether or not the cell reselection condition is satisfied.

  Here, the cell reselection condition is that a state in which the value obtained by subtracting the correction value R from the measured value Qn of any one of the neighboring cells exceeds the measured value Qs of the own station cell is a predetermined time (second predetermined time = Teleselection). ) Applicable if continued.

  That is, the cell reselection condition is satisfied when the state in which (Qn−R)> Qs continues for a predetermined time (Teleselection).

  Therefore, for example, even if the mobile communication terminal apparatus 100 is located near the boundary between two cells and the measured values of both cells in the mobile communication terminal apparatus 100 are close to each other, as shown in FIG. Further, by treating the measurement value Qn of the neighboring cells as low as the correction value R, subsequent cell reselection is suppressed.

  Here, the initial value of the correction value R is “0”, and the correction value R is increased by X [dB] each time it is determined that a flutter has occurred. That is, every time it is determined that a flutter has occurred, the cell reselection condition is difficult to be satisfied.

  Each time it is determined that a flutter has occurred, the flutter monitoring counter 11 is initialized (the count value is set to “0”), and the flutter monitoring timer 10 is restarted (the time counting operation is restarted from the beginning). And).

  Further, every time the flutter monitoring timer 10 expires before the count value of the flutter monitoring counter 11 exceeds a predetermined value, the correction value R is decreased by X. That is, when the predetermined time T elapses without flickering, the correction value R is decreased by X to cancel the effect of suppressing the cell reselection operation.

  Even when the flutter monitoring timer 10 expires before the count value of the flutter monitoring counter 11 reaches a predetermined value or more, the initialization of the flutter monitoring counter 11 and the restart of the flutter monitoring timer 10 are performed each time. Start up.

  However, when the correction value R when the flicker monitoring timer 10 expires is “0”, the process of decreasing the correction value R is not performed (R ≧ 0).

  When no flutter occurs, the correction value R is maintained at “0”. On the other hand, since the correction value R is effective as a correction value only after the flutter occurs, it is determined that the flutter has occurred. In this case, it can be said that the cell reselection condition is corrected by the correction value and the condition becomes difficult to be satisfied.

  Next, the operation of mobile communication terminal apparatus 100 will be described with reference to the flowchart of FIG.

  First, when the power is turned on, the mobile communication terminal apparatus 100 measures the reception intensity / quality of the radio signal from the radio base station 200 by the reception intensity / quality measurement unit 5 in order to determine its own cell. The reception intensity / quality measurement unit 5 notifies the cell selection control unit 6 of the measurement value. The cell selection control unit 6 searches for the cell with the best measured value, and transmits a cell selection execution notification including cell information (cell information) to the processing control unit 7 so that the cell is the local station cell. (Instruct cell selection execution).

  Based on the cell information notified from the cell selection control unit 6, the processing control unit 7 performs processing for setting the cell as its own cell (step S 1), and stores the SC of the cell set as its own cell in step S 1 as a memory. 8 is stored in the SC history storage unit 9 (step S2).

  Here, although up to N SCs can be stored in the SC history storage unit 9 of the memory 8, a specific example of the storage method will be described. The SC history storage unit 9 has N lists of SC (1) to SC (N), and can store one SC in each list. The SC of the cell that is finally set as its own cell is stored in SC (1). In SC (2) to SC (N), when there is an SC older than SC (1), data is stored in the newest order. If more than N SCs are stored, the oldest SC (N) SC is deleted and the SCs SC (1) to SC (N-1) are changed to SC (2) to SC (N). It is assumed that the SC of the cell that has finally become its own cell is stored in SC (1).

  Subsequently, the process control unit 7 instructs the flutter monitoring timer 10 to start, and upon receiving this instruction, the flutter monitoring timer 10 starts a time counting operation at time T1 (step S3).

  In the cell reselection control unit 6, when the flutter monitoring timer 10 is being activated (count value of the flutter monitoring timer 10 <T 1) (Yes in step S 4), the electric field strength / quality measurement unit 5 periodically notifies the cell reselection control unit 6. Whether or not the cell reselection condition ((Qn-R)> Qs is maintained for a predetermined time (Teleselection)) is satisfied (step S5). Yes), a cell reselection execution notification including the cell information of the transfer destination is transmitted to the process control unit 7.

  The processing control unit 7 that has received the cell reselection execution notification performs the local cell migration process based on the notified cell information (step S6), and the SC and the memory 8 of the migrated cell (migration destination cell) Are compared with the SC history storage unit 9 (step S7). As a result of the comparison, if the SC of the migrated cell is not found from the SC history storage unit 9, that is, if the migrated cell is not the cell that was previously set as the local station cell (No in step S7), it is determined in step S6. The SC of the cell serving as the station cell is stored in the SC history storage unit 9 of the memory 8 (step S13), and the process proceeds to a cell selection execution notification waiting state (step S5).

  If the SC of the migrated cell is found from the SC history storage unit 9 in step S7, that is, if the migrated cell is a cell that was previously set as the local station cell (Yes in step S7), for flutter monitoring The count value (Count) of the counter 11 is incremented by “1” (step S8), and whether or not the count value is equal to or greater than a predetermined threshold value (THRESH), that is, whether or not a flutter has occurred. Judgment is made (step S9).

  When the count value of the flutter monitoring counter 11 is less than the threshold value, that is, when it is determined that no flutter has occurred (No in step S9), the SC of the cell serving as the local cell is stored in the memory 8. The data is stored in the SC history storage unit 9 (step S13), and the process proceeds to a cell selection execution notification waiting state (step S5).

  On the other hand, when the count value of the flutter monitoring counter 11 is greater than or equal to the threshold value in step S9, that is, when it is determined that flutter has occurred (Yes in step S9), the process control unit 7 performs the cell reselection control unit. 6 is notified to increase the correction value (R [dB]) for flicker suppression by X [dB] (step S10), and the flutter monitoring counter 11 is used to monitor flicker occurrence from the beginning again. Initialization (step S11) and a restart request for the flutter monitoring timer 10 (step S12). Thereafter, in step S6, the SC of the cell set as the local station cell is stored in the SC history storage unit 9 in the memory 8 (step S13), and the process proceeds to a cell reselection execution notification waiting state (step S5). Here, the cell reselection control unit 6 uses the correction value R, which is increased by X in the previous step S10, to determine whether or not the cell reselection condition is satisfied, and thereafter the cell reselection operation is suppressed. It will be. That is, fluttering is suppressed.

  The process control unit 7 monitors the state of the flutter monitoring timer 10 together with the cell selection execution notification waiting in step S5 (step S4). The flutter monitoring timer 10 indicates that the timing operation has expired. When a notification (timeout notification) is received (No in step S4), it is determined that no flutter has occurred during the timing operation, and only when the correction value R at that stage is greater than “0” (step In S14, the correction value R is subtracted by X (step S15). However, if the correction value R is already “0” (No in step S14), the process in step S15 is skipped.

  Thereafter, the process control unit 7 initializes the flutter monitoring counter 11 (step S16) and requests to restart the flutter monitoring timer 10 (step S17) in order to monitor the occurrence of flicker from the beginning again. The process shifts to a reselection execution notification waiting state (step S5).

  Here, the cell reselection control unit 6 uses the correction value R, which is decreased by X in step S15, to determine whether the cell reselection condition is satisfied. That is, when the fluttering is in the restraining direction as described above, the fluttering suppression effect is gradually released by decreasing the correction value by X [dB].

  According to the embodiment as described above, when the number of times the cell that was previously set as the local station cell is newly set as the local station cell reaches a predetermined number within a predetermined time, a flutter of the cell reselection operation has occurred. Therefore, the occurrence of fluttering can be reliably determined. Further, since it is possible to suppress the cell reselection operation when it is determined that the flutter has occurred, it is possible to reliably suppress the subsequent flutter when the flutter has occurred.

  More specifically, the transition target cell (cell that becomes a new local cell) that satisfies the cell reselection condition (Qn-R> Qs is continued for a predetermined time) is a cell that was previously set as the local station cell. It is determined that every time a predetermined number of times is reached within a predetermined time, it is determined that a flutter has occurred, and by increasing the correction value R, the flutter of the cell reselection operation can be suppressed.

  By suppressing the flutter in this way, the power consumption of the mobile communication terminal device 100 can be suppressed and the standby time can be extended.

  In addition, it is determined that the transition target cell (cell that becomes a new local cell) in which the cell reselection condition (Qn-R> Qs is continued for a predetermined time) is satisfied is a cell that has been previously set as the local station cell. However, by increasing the correction value R every time the predetermined time elapses before the predetermined number of times is reached, the flutter suppression effect can be gradually released.

  In the above embodiment, an example has been described in which the SC history is updated unconditionally (step S13) every time the cell reselection operation (step S7) is performed. Only when the SC (identification information) of the cell set as the station cell is not stored in the SC history storage unit (own cell history storage means) 9, the processing control unit 7 sets the SC of the new local cell to the SC. You may make it memorize | store in the log | history memory | storage part 9. FIG.

It is a schematic diagram which shows a mobile communication system provided with the mobile communication terminal device which concerns on this invention. It is a functional block diagram which shows the mobile communication terminal device which concerns on this invention. It is a flowchart which shows operation | movement of the mobile communication terminal device of FIG. It is a figure for demonstrating the mechanism which can suppress the flutter of cell reselection operation | movement by the mobile communication terminal device of FIG. It is a figure for demonstrating the mechanism in which the flutter of cell reselection operation | movement generate | occur | produces in the conventional mobile communication terminal device. It is a functional block diagram which shows the mobile communication terminal of patent document 1. FIG.

Explanation of symbols

6 Cell selection control unit (cell reselection control means)
7 Process control unit (cell reselection control means, flicker generation determination means, suppression control means, release control means, initialization means)
9 SC history storage unit (own cell history storage means)
10 Flapping monitoring timer (time measuring means)
11 Flutter monitoring counter (counting means)
100 Mobile communication terminal device

Claims (15)

In the cell reselection device provided in the mobile communication terminal device of the code division multiple access method,
A cell reselection control means for performing a cell reselection operation for reselecting a local station cell when a cell reselection condition is satisfied;
Counting means for counting the number of times that a cell that was previously set as a local station cell is newly set as the local station cell by the cell reselection operation;
A time measuring means for measuring a predetermined time;
A flutter occurrence determination means for determining that a flutter of the cell reselection operation has occurred when the count value by the counting means reaches a predetermined number before the time counting operation by the time counting means expires;
A suppression control unit that suppresses a cell reselection operation when it is determined by the flutter occurrence determination unit that a flutter has occurred;
A cell reselection device comprising:   The suppression control unit performs a cell reselection operation by correcting the cell reselection condition with a correction value so that the condition is difficult to be satisfied when the flicker occurrence determination unit determines that the flicker has occurred. The cell reselection device according to claim 1, wherein the cell reselection device is suppressed.   The suppression control unit increases the correction value of the cell reselection condition every time it is determined by the flicker generation determination unit that flicker has occurred, and makes the condition more difficult to be satisfied. Item 3. The cell reselection device according to Item 2.   When the time counting operation by the time measuring means expires before the count value by the counting means reaches the predetermined number, the correction value of the cell reselection condition added by the suppression control means is decreased, The cell reselection device according to claim 3, further comprising release control means for releasing the effect of suppressing the selection operation.   An initialization means for resetting the count value by the counting means each time the correction value of the cell reselection condition is increased by the suppression control means, and for restarting the timing operation by the timing means from the beginning; The cell reselection device according to claim 3.   Each time the correction value of the cell reselection condition is increased by the suppression control means and every time the correction value is decreased by the release control means, the counting operation by the counting means and the time measurement by the time measuring means are performed. The cell reselection device according to claim 4, further comprising initialization means for initializing the operation. If the received radio wave intensity of the local cell is Qs, the received radio wave intensity of the neighboring cells is Qn, and the correction value is R,
The cell reselection condition according to any one of claims 2 to 6, wherein the cell reselection condition is satisfied when a state of (Qn-R)> Qs continues for a second predetermined time. apparatus. A self-station cell history storage means for storing and holding a predetermined number of cell identification information previously set as the self-station cell,
The counting means counts the number of times the identification information of a cell newly set as a local cell by the cell reselection operation matches the identification information stored and held in the local cell history storage means. The cell reselection device according to any one of claims 1 to 7. In a code division multiple access mobile communication terminal device,
A mobile communication terminal device comprising the cell reselection device according to any one of claims 1 to 8.   The mobile communication terminal apparatus according to claim 9, wherein the mobile communication terminal apparatus is a mobile phone. In a method of performing cell reselection in a mobile communication terminal apparatus of code division multiple access method,
A condition establishment determination step for determining establishment of a cell reselection condition;
When it is determined that the cell reselection condition is satisfied in the condition establishment determination step, a cell reselection step of reselecting the own station cell;
A counting step for counting the number of times the cell that was previously set as the local station cell is newly set as the local station cell by the cell reselection step;
A time measuring process for measuring a predetermined time;
A flutter occurrence determination step of determining that a flutter of the cell reselection operation has occurred when the count value of the count step reaches a predetermined number before the time counting operation by the time counting step expires;
When it is determined that a flutter has occurred in the flutter occurrence determination step, a suppression step for suppressing a cell reselection operation;
A cell reselection method comprising:   In the suppression step, when it is determined in the flicker occurrence determination step that the flicker has occurred, the cell reselection operation is suppressed by correcting the cell reselection condition with a correction value to make it difficult to satisfy the condition. The cell reselection method according to claim 11, wherein: In a computer executable program,
Condition establishment determination processing for determining establishment of a cell reselection condition in a mobile communication terminal apparatus of code division multiple access method;
A cell reselection process for reselecting a local cell when it is determined in the condition establishment determination process that a cell reselection condition is established;
A count process for counting the number of times the cell that was previously set as the local station cell is newly set as the local station cell by the cell reselection process;
A timing process for timing a predetermined time;
A flutter occurrence determination process for determining that a flutter of the cell reselection operation has occurred when the count value by the count process reaches a predetermined number before the time counting operation by the time counting process expires;
When it is determined that a flicker has occurred by the flutter occurrence determination process, a suppression process for suppressing a cell reselection operation;
A program characterized by executing   In the suppression process, when it is determined by the flicker occurrence determination process that the flicker has occurred, the cell reselection operation is suppressed by correcting the cell reselection condition with a correction value to make it difficult to satisfy the condition. The program according to claim 13. A computer-readable recording medium, wherein the program according to claim 13 or 14 is stored.

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