JP2006222651A - Mobile communication controller and neighbor cell list information structuring method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mobile communication controller capable of properly listing up information on neighboring cells that terminals use. <P>SOLUTION: A database device 31 prestores cell information on neighboring cells by the cells. A storage device 28 stores cell information on a cell that a mobile communication terminal uses and a use start order of the cell in use. A data processor 22 preferentially extracts from the database device 31 cell information on neighboring cells as to the cell in use which is in the end place of the use start order among cells in use stored in the storage device 28. An output device 33 stores the cell information on the neighboring cells extracted by the data processor 22 in a message reported to the mobile communication terminal. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a CDMA mobile communication system, and more particularly, to a radio network controller for a CDMA mobile communication system.

  FIG. 4 is a block diagram showing a configuration example of a general CDMA mobile communication system. Referring to FIG. 4, the CDMA mobile communication system includes radio network controllers (hereinafter referred to as “RNC”) 91 and 92 and radio base stations 93 and 94. The RNCs 91 and 92 are connected to the core network 90. Radio base stations 93 and 94 are connected to the RNC 91. The areas covered by the radio base station 93 are the cell 95 and the cell 96. The area covered by the radio base station 94 is the cell 97. An area covered by the cells 95 to 97 is a service area. A cell is the smallest unit that constitutes a service area. The number of each device shown here is an example for explanation, and is not limited to this.

  In the CDMA mobile communication system, a mobile communication terminal (hereinafter referred to as “terminal”) 98 can be provided with a wireless CDMA mobile communication service within a service area. Even if the terminal 98 moves across cells, the communication service for the terminal 98 can be continuously provided without disconnecting the communication and without degrading the communication quality. A technique that enables this service is handover.

  For example, when a terminal 98 communicating in a cell 95 moves in the direction of another cell 96 adjacent to the cell 95 being used for the communication service, the radio wave quality of the cell 95 deteriorates, and the radio wave quality of the cell 96 Can be considered to improve.

  When the 96-cell radio wave has a quality equivalent to or better than that of the cell 95, the terminal 98 starts using the cell 96 in addition to the cell 95. As a result, the two cells 95 and 96 are in use. Further, when the terminal 98 further moves out of the cell 95, the quality of the radio wave of the cell 95 is extremely deteriorated. When this happens, the terminal 98 stops using the cell 95.

  In this way, the terminal 98 can move while continuing communication by switching the wireless line to the adjacent cell in accordance with the change in the radio wave quality. Further, as can be seen from the above example, the terminal 98 may use radio lines of two or more cells at the same time.

  In general, a cell that can be the next handover destination of a terminal in a certain cell is limited to a specific cell adjacent to the cell in use. An adjacent cell that a terminal in a certain cell may select as the next handover destination is called a neighbor cell for that cell. In the CDMA mobile communication system, the terminal needs to know cell information of neighboring cells in order to perform handover. Cell information is information necessary for handover including a cell number for enabling cell identification.

  In order to enable handover, neighboring cell list information is provided from the RNC to the terminal (see, for example, Patent Document 1). In general, since there are a plurality of cells around one cell, there are a plurality of neighboring cells for one cell. Therefore, information on a plurality of cells determined as neighboring cells of a certain cell is stored in the neighboring cell list information. It is specified that the neighbor cell list information for a certain cell includes the cell itself.

A terminal can be handed over to a neighboring cell by receiving neighboring cell list information. The RNC has, as a database, neighboring cell list information for each cell under its control. Then, the RNC retrieves neighboring cell list information about the cell being used by the terminal from the database, and notifies the terminal of the information. For notification of neighboring cell list information, a signal message called Measurement Control is used.
Japanese National Patent Publication No. 10-509845

  FIG. 5 is a block diagram showing a configuration of a conventional RNC. Here, the RNC 91 is illustrated, but the RNC 92 has the same configuration. Referring to FIG. 5, a conventional RNC 91 has an input device 71, a data processing device 72, a storage device 78, a database device 81, and an output device 83. The data processing device 72 includes an in-use cell information extracting unit 73, an in-use cell information writing unit 74, an in-use cell number extracting unit 75, a neighboring cell list information extracting unit 76, and a neighboring cell list information writing unit 77. Yes.

  The storage device 78 includes an in-use cell information table storage unit 79 and a neighboring cell list information generation table storage unit 80. The database device 81 has a neighboring cell list information storage unit 82.

  The input device 71 receives a neighboring cell list information generation request for an arbitrary terminal, and instructs the data processing device 72 to start processing.

  The neighboring cell list information storage unit 82 of the database device 81 stores cell information of neighboring cells for each subordinate cell in advance as a list. The neighbor cell list information storage unit 82 stores neighbor cell list information for a maximum of 32 cells for each cell.

  The neighboring cell list information generation table storage unit 80 of the storage device 78 holds information for generating neighboring cell list information to be notified to the terminal in a table. The neighbor cell list information generation table storage unit 80 can store neighbor cell list information for a maximum of 32 cells for each terminal.

  The in-use cell information table storage unit 79 stores cell information used by each terminal in communication. When a cell is newly used by handover, the in-use cell information table storage unit 79 adds the cell information to the table. In addition, when a cell in use is deleted by handover, the cell information table storage unit 79 in use deletes the cell information of the deleted cell from the table. Here, it is assumed that the maximum number of cells that one terminal can use simultaneously is three cells. Therefore, the in-use cell information table storage unit 79 can store cell information for up to three cells for one terminal.

  The in-use cell information extraction unit 73 of the data processing device 72 extracts cell information of a cell in use by a certain terminal from the in-use cell information table storage unit 79.

  The in-use cell information writing unit 74 stores all the cell information extracted by the in-use cell information extraction unit 73 in the neighboring cell list information generation table storage unit 80.

  The in-use cell number extraction unit 75 extracts the cell numbers of the in-use cells one by one from the in-use cell information table storage unit 79.

  The neighboring cell list information extracting unit 76 extracts the neighboring cell list information for the cell having the cell number extracted by the in-use cell number extracting unit 75 from the neighboring cell list information storage unit 82 of the database device 81.

  The neighboring cell list information writing unit 77 stores the cell information included in the neighboring cell list information extracted by the neighboring cell list information extracting unit 76 in the neighboring cell list information generation table storage unit 80. One neighboring cell list information includes cell information for a maximum of 32 cells. If the cell information to be stored is already stored in the neighboring cell list information generation table storage unit 80, the neighboring cell list information writing unit 77 duplicates the cell information in the neighboring cell list information generation table storage unit 80. And do not store.

  If there are a plurality of used cells in the used cell information table storage unit 79, the used cell number extracting unit 75, the neighboring cell list information extracting unit 76, and the neighboring cell list information writing unit 77 use the above storage process. Repeat for the number of middle cells. Since the in-use cell information table storage unit 79 stores the cell information of the in-use cells for each terminal for a maximum of three cells, the above operation is repeated up to three times for one terminal. In addition, since the neighbor cell list information that can be stored in the neighbor cell list information generation table storage unit 80 is a maximum of 32 cells, when the neighbor cell information of one terminal reaches 32 cells, the data processing device 72 The storage process ends.

  The output device 83 stores the neighbor cell list information generated in the neighbor cell list information generation table storage unit 80 of the storage device 78 by the storage processing of the data processing device 72 in the Measurement Control signal message and transmits it to the terminal.

  The conventional RNC 91 having the above configuration notifies each terminal of cell information of neighboring cells that are candidates for the handover destination of each terminal through the radio base station by the series of operations of the above-described units.

  The area for storing the neighbor cell list information in the Measurement Control signal message is limited.

  According to the 3GPP recommendation, the neighbor cell list information is defined up to cell information for 32 cells including in-use cells. That is, considering the case where there is one cell in use, a maximum of 31 neighboring cells can be determined for one cell. In the RNC 91, up to 31 neighbor cells for each cell are stored in the database as neighbor cell list information.

  On the other hand, the terminal 98 can use a plurality of cells at the same time, but there is an upper limit on the number of cells, and at present, the maximum number is generally 3 cells. Then, in a terminal using three cells, if there are 31 neighboring cells in each of the three cells, three own cells are added, and the total number of neighboring cells is 96 cells at the maximum.

  However, in general, it is considered that the neighboring cells for three in-use cells that are in use at the same time partially overlap, and there may be less than 31 neighboring cells for one cell. It is considered rare that there are 96 neighboring cells. However, there is a possibility that the neighboring cell list information to be notified to one terminal exceeds the upper limit of 32 cells.

  When the neighboring cell list information reaches 32 cells, the RNC 91 stops the storage process, and notifies the terminal of the neighboring cell list information stored in the neighboring cell list information generation table storage unit 80 so far. Therefore, there is a possibility that information on neighboring cells that are handover destination candidates is not properly notified to the terminal 98.

  For example, depending on the moving direction of the terminal 98, since information on some neighboring cells is not notified, it may occur that the handover that should have been possible cannot be performed. As a result, the communication of the terminal 98 may be disconnected.

  An object of the present invention is to provide a mobile communication control apparatus capable of appropriately listing neighboring cell information about a cell being used by a terminal.

In order to achieve the above object, a mobile communication control device of the present invention includes:
In a mobile communication system, a mobile communication control apparatus for notifying the mobile communication terminal of information on neighboring cells for cells used by the mobile communication terminal,
A database device that pre-stores cell information of neighboring cells for each cell;
A storage device for storing cell information of a cell in use of the mobile communication terminal and a use start order of the cell in use;
A data processing device that preferentially takes out cell information of neighboring cells for the used cell whose use start order is the last among the used cells stored in the storage device, from the database device;
And an output device that stores cell information of the neighboring cell extracted by the data processing device in a message notifying the mobile communication terminal.

  According to the present invention, since the use start order is recorded and the cell information of the neighbor cell of the last used cell added based on the order is preferentially extracted and stored in the message, the next hand It is possible to preferentially notify a mobile communication terminal of a neighboring cell with a high probability of being an over destination. Even if cell information for the upper limit number of cells is stored in the middle of the storage process and the process is terminated, neighboring cells with a high probability of becoming the next handover destination are surely listed.

  In addition, the data processing device extracts from the storage device in order from the cell information of the in-use cell whose use start order is later, and sets cell information of neighboring cells for the in-use cell from which the cell information has been extracted to a predetermined upper limit. It is good also as taking out from the said database apparatus within the number of cells.

  According to this, since the data processing device sequentially extracts from the used cell added last based on the usage start order and extracts the neighboring cell list information from the database device, the neighborhood having a high probability of becoming the next handover destination Up to the maximum number of cells in order from the cell can be notified to the mobile communication terminal.

  Further, the data processing device takes out the cell information of the neighboring cell for the cell in use and records it in the storage device, and if the cell information to be recorded is already recorded in the storage device, The cell information may not be recorded redundantly.

  The mobile communication system may be configured in a radio network control apparatus that accommodates at least one radio base station.

  According to the present invention, since the use start order is recorded and the cell information of the neighbor cell of the last used cell added based on the order is preferentially extracted and stored in the message, the next hand It is possible to preferentially list neighboring cells with a high probability of being an over destination.

  Embodiments for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration example of a CDMA mobile communication system according to an embodiment of the present invention. Referring to FIG. 1, the CDMA mobile communication system includes radio network controllers (hereinafter referred to as “RNC”) 11 and 12 and radio base stations 13 and 14. The RNCs 11 and 12 are connected to the core network 10. Radio base stations 13 and 14 are connected to the RNC 11. The areas covered by the radio base station 13 are the cell 15 and the cell 16. The area covered by the radio base station 14 is a cell 17. An area covered by the cells 15 to 17 is a service area. A cell is the smallest unit that constitutes a service area. The number of each device shown here is an example for explanation, and is not limited to this.

  In the CDMA mobile communication system, a mobile communication terminal (hereinafter referred to as “terminal”) 18 can receive a CDMA mobile communication service by radio within a service area. Even if the terminal 18 moves across cells, the communication service for the terminal 18 can be continuously provided without disconnecting the communication and without degrading the communication quality. A technique that enables this service is handover.

  For example, when the terminal 18 that performs communication in the cell 15 moves in the direction of another cell 16 adjacent to the cell 15 being used for the communication service, the radio wave quality of the cell 15 deteriorates, and the radio wave quality of the cell 16 Can be considered to improve.

  If the radio waves of 16 cells become equal to or better than the radio waves of cell 15, terminal 18 starts using cell 16 in addition to cell 15. As a result, the two cells 15 and 16 are in use. Further, when the terminal 18 further moves out of the cell 15, the radio wave quality of the cell 15 is extremely deteriorated. When this happens, the terminal 18 stops using the cell 15.

  In this manner, the terminal 18 can move while continuing communication by switching the wireless line to the adjacent cell in accordance with the change in the radio wave quality. Further, as can be seen from the above example, the terminal 18 may use radio lines of two or more cells at the same time.

  In general, a cell that can be the next handover destination of a terminal in a certain cell is limited to a specific cell adjacent to the cell in use. An adjacent cell that a terminal in a certain cell may select as the next handover destination is called a neighbor cell for that cell. In the CDMA mobile communication system, the terminal needs to know cell information of neighboring cells in order to perform handover. Cell information is information necessary for handover including a cell number for enabling cell identification.

  In order to enable handover, neighbor cell list information is provided from the RNC to the terminal. In general, since there are a plurality of cells around one cell, there are a plurality of neighboring cells for one cell. Therefore, information on a plurality of cells determined as neighboring cells of a certain cell is stored in the neighboring cell list information. It is specified that the neighbor cell list information for a certain cell includes the cell itself.

  A terminal can be handed over to a neighboring cell by receiving neighboring cell list information. The RNC has, as a database, neighboring cell list information for each cell under its control. Then, the RNC retrieves neighboring cell list information about the cell being used by the terminal from the database, and notifies the terminal of the information. For notification of neighboring cell list information, a signal message called Measurement Control is used.

  FIG. 2 is a block diagram showing the configuration of the RNC according to this embodiment. Here, the RNC 11 is illustrated, but the RNC 12 has the same configuration. Referring to FIG. 2, the RNC 11 includes an input device 21, a data processing device 22, a storage device 28, a database device 31, and an output device 33. The data processing device 22 includes an in-use cell information extracting unit 23, an in-use cell information writing unit 24, an in-use cell number extracting unit 25, a neighboring cell list information extracting unit 26, and a neighboring cell list information writing unit 27. Yes.

  The storage device 28 includes an in-use cell information table storage unit 29 and a neighboring cell list information generation table storage unit 30. The database device 31 has a neighboring cell list information storage unit 32.

  The input device 21 receives a neighboring cell list information generation request for an arbitrary terminal, and instructs the data processing device 22 to start processing.

  The neighboring cell list information storage unit 32 of the database device 31 stores in advance cell information of neighboring cells for each subordinate cell as a list. The information in the neighbor cell list information storage unit 32 is stored so that cell information of neighbor cells for the cell indicated by the key can be extracted using the cell number as a key. The neighbor cell list information storage unit 32 stores neighbor cell list information for a maximum of 32 cells for each cell.

  The neighboring cell list information generation table storage unit 30 of the storage device 28 holds information for generating neighboring cell list information to be notified to the terminal in a table. The neighbor cell list information generation table storage unit 30 can store neighbor cell list information for a maximum of 32 cells for each terminal.

  The in-use cell information table storage unit 29 stores information on cells used by each terminal in communication and the order in which the cells are added to the table. If a cell is newly in use by handover, the in-use cell information table storage unit 29 adds the cell information to the table. In addition, when a cell in use is deleted by handover, the cell information table storage unit 29 in use deletes the cell information of the deleted cell from the table. Here, it is assumed that the maximum number of cells that one terminal can use simultaneously is three cells. The in-use cell information table storage unit 29 is capable of storing cell information for up to three cells for one terminal.

  The in-use cell information extracting unit 23 of the data processing device 22 extracts cell information of a cell in use by a certain terminal from the in-use cell information table storage unit 29.

  The in-use cell information writing unit 24 stores all the cell information extracted by the in-use cell information extraction unit 23 in the neighboring cell list information generation table storage unit 30.

  The in-use cell number extraction unit 25 extracts the cell numbers of the cells in use from the in-use cell information table storage unit 29 one by one from the later addition order to the table.

  The neighboring cell list information extracting unit 26 extracts the neighboring cell list information for the cell having the cell number extracted by the in-use cell number extracting unit 25 from the neighboring cell list information storage unit 32 of the database device 31.

  The neighboring cell list information writing unit 27 stores the cell information included in the neighboring cell list information extracted by the neighboring cell list information extracting unit 26 in the neighboring cell list information generation table storage unit 30. One neighboring cell list information includes cell information for a maximum of 32 cells. If the cell information to be stored is already stored in the neighboring cell list information generation table storage unit 30, the neighboring cell list information writing unit 27 duplicates the cell information in the neighboring cell list information generation table storage unit 30. And do not store.

  If there are a plurality of used cells in the used cell information table storage unit 29, the used cell number extracting unit 25, the neighboring cell list information extracting unit 26, and the neighboring cell list information writing unit 27 use the above storage process. Repeat for the number of middle cells. Since the in-use cell information table storage unit 29 stores the cell information of the in-use cells for each terminal up to three cells, the above-described operation is repeated up to three times for one terminal. Also, since the neighbor cell list information that can be stored in the neighbor cell list information generation table storage unit 30 is a maximum of 32 cells, when the neighbor cell information of one terminal reaches 32 cells, the data processing device 72 The storage process ends.

  The output device 33 stores the neighbor cell list information generated in the neighbor cell list information generation table storage unit 30 of the storage device 28 by the storage processing of the data processing device 22 in the Measurement Control signal message and transmits it to the terminal.

  The conventional RNC 11 having the above configuration notifies each terminal of cell information of a neighboring cell that is a handover destination candidate of each terminal through the radio base station by a series of operations of each unit described above.

  FIG. 3 is a flowchart showing the operation of the RNC according to the present embodiment.

  First, the in-use cell information extraction unit 23 of the data processing device 22 that has started processing in response to a request from the input device 1 extracts out-of-use cell information from the in-use cell information table storage unit 29 (step 101). .

  Next, the in-use cell information writing unit 24 of the data processing device 22 stores the cell information of the cell in use in the neighboring cell list information generation table storage unit 30 (step 102).

  Next, the in-use cell number extraction unit 23 reads the cell addition order from the in-use cell information table storage unit 29, and extracts one cell number of the in-use cell from the one added last by the handover (step 103). ).

  Next, the neighboring cell list information retrieving unit 26 retrieves neighboring cell list information from the neighboring cell list information storage unit 32 of the database device 31 using the cell number as a key (step 104).

  Next, the neighboring cell list information writing unit 27 stores the cell information included in the neighboring cell list information in the neighboring cell list information generation table storage unit 30 (step 105). At this time, if the cell information to be stored is already stored in the table, the neighboring cell list information writing unit 27 does not store it redundantly.

  Next, the data processing device 22 determines whether there is another in-use cell in the in-use cell information table storage unit 29 (step 106). If there is another in-use cell, the data processing device 22 returns to the process of step 103 and repeats the process for the next in-use cell. Steps 103 to 106 are repeated up to three times.

  If there is no other cell in use in the determination of step 106, the data processing device 22 ends the processing, and the output device 33 sends the neighboring cell list information generated in the neighboring cell list information generation table storage unit 30 to the Measurement Control signal. It is stored in the message (step 107). The neighbor cell list information stored in the Measurement Control signal message is transmitted to the terminal.

  In general, it can be said that there is a high probability that a neighboring cell of a cell newly added by handover is the next handover destination. According to the present embodiment, the RNC 91 records the addition order in the storage device 28, and based on the order, the data processing device 22 stores the cell information of the neighboring cell of the currently used cell added last. Since it is preferentially taken out from the database device 31 and stored in the signal message notified to the terminal 98, neighboring cells with a high probability of becoming the next handover destination of the terminal 98 can be preferentially listed. Even if cell information for the upper limit number of cells is stored in the middle of the storage process and the process is terminated, neighboring cells with a high probability of becoming the next handover destination are surely listed.

  Further, according to the present embodiment, the data processing device 22 sequentially extracts from the used cell added last based on the use start order, and extracts the neighboring cell list information from the database device. Up to the upper limit number of cells can be notified to the terminal 98 in order from a neighboring cell with a high probability of

  In the present embodiment, as a preferred example, a configuration has been described in which the neighbor cell list information is notified from the radio network control device to the terminal, but the present invention is not limited to this configuration. The present invention can be widely applied to a configuration in which neighbor cell list information is notified to a terminal from any device constituting a mobile communication system.

  In the present embodiment, as a preferred example, an example is shown in which neighboring cells are recorded in order from the in-use cell whose order of addition is late, but the present invention is not limited to this. As long as in-use cells with a slow addition order can be preferentially taken out and notified to the terminal, they may be taken out in any order. For example, it is possible to take out the cell information extracted first, and after the upper limit of 32 cells is exceeded, the cell information extracted first may be overwritten.

  In the present embodiment, as a preferred example, all the used cells are extracted in order from the slow addition order, and the neighboring cells are extracted, but the present invention is not limited to this. For example, as long as a neighboring cell for the last used cell that has been added is preferentially taken out and notified, the order of subsequent used cells may not necessarily be in the slow addition order. Alternatively, only the neighboring cells for the last used cell added may be extracted and notified, and the neighboring cells of the subsequent used cells may not be notified.

It is a block diagram which shows the structural example of the CDMA mobile communication system by one Embodiment of this invention. It is a block diagram which shows the structure of RNC by this embodiment. It is a flowchart which shows operation | movement of RNC by this embodiment. It is a block diagram which shows the structural example of a general CDMA mobile communication system. It is a block diagram which shows the structure of the conventional RNC.

Explanation of symbols

10 Core network 11, 12 Radio network controller (RNC)
13, 14 Radio base station 15-17 Cell 18 Mobile communication terminal (terminal)
DESCRIPTION OF SYMBOLS 21 Input device 22 Data processing device 23 In-use cell information extraction part 24 In-use cell information writing part 25 In-use cell number extraction part 26 Neighbor cell list information extraction part 27 Neighbor cell list information writing part 28 Storage device 29 In-use cell information Table storage unit 30 Neighbor cell list information generation table storage unit 31 Database device 32 Neighbor cell list information storage unit 33 Output device 101 to 107 steps

Claims (7)

In a mobile communication system, a mobile communication control apparatus for notifying the mobile communication terminal of information on neighboring cells for cells used by the mobile communication terminal,
A database device that pre-stores cell information of neighboring cells for each cell;
A storage device for storing cell information of a cell in use of the mobile communication terminal and a use start order of the cell in use;
A data processing device that preferentially takes out cell information of neighboring cells for the used cell whose use start order is the last among the used cells stored in the storage device, from the database device;
A mobile communication control device comprising: an output device that stores cell information of the neighboring cell extracted by the data processing device in a message notifying the mobile communication terminal.   The data processing device extracts from the storage device in order from the cell information of the used cells whose use start order is later, and obtains cell information of neighboring cells for the used cells from which the cell information has been extracted, as a predetermined upper limit number of cells. The mobile communication control device according to claim 1, wherein the mobile communication control device is taken out from the database device within 5 minutes.   The data processing device extracts cell information of the neighboring cell for the cell in use and records it in the storage device, and if the cell information to be recorded is already recorded in the storage device, the cell The mobile communication control device according to claim 1 or 2, wherein information is not recorded redundantly.   The mobile communication control apparatus according to claim 1, wherein the mobile communication control apparatus is configured in a radio network control apparatus that accommodates at least one radio base station in the mobile communication system. In a mobile communication system, a neighbor cell list information construction method for constructing neighbor cell information for a cell being used by a mobile communication terminal,
Storing cell information of neighboring cells for each cell in a database in advance;
Managing the cell information of the cell in use of the mobile communication terminal and the usage start order of the cell in use in a storage device;
Preferentially taking out cell information of neighboring cells for the used cell whose use start order is the last among the used cells managed by the storage device from the database;
Recording the cell information of the extracted neighboring cells in the storage device.   The cell information of the in-use cell whose use start order is later is extracted from the storage device in order, and the cell information of the neighboring cell for the in-use cell from which the cell information has been extracted is extracted from the database within the predetermined upper limit cell number. 6. The neighbor cell list information construction method according to claim 5, wherein the neighbor cell list information is recorded in the storage device.   The cell information of the neighboring cell for the cell in use is extracted and recorded in the storage device. If the cell information to be recorded is already recorded in the storage device, the cell information is recorded in duplicate. The neighboring cell list information construction method according to claim 5 or 6, wherein:

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