JP2020167464A - Setting device, portable terminal system, setting method, and program - Google Patents

Abstract

To perform high-speed setting of identification information which identifies cells of a base station.SOLUTION: Disclosed is a setting method for setting identification information for identifying cells of a base station to which a portable terminal is connected. This method includes the steps of: acquiring arrangement information on a plurality of base stations; selecting a plurality of target base stations having the cells to which the identification information is to be set, among the plurality of base stations; dividing the plurality of base stations into a plurality of clusters based on the arrangement information and arrangement of a plurality of selected target base stations; and setting identification information on the selected cells possessed by the plurality of target base stations for each of the divided clusters. When a value of a physical cell identifier (PCI) assigned to each of the cells is m, and the number of cells possessed by each of the plurality of base stations is n, the identification information is calculated as MOD (m,n).SELECTED DRAWING: Figure 10

Description

The present invention relates to a setting device, a mobile terminal system, a setting method, and a program.

In the base station that communicates with the mobile terminal, identification information is set for each cell that divides the communicable area. Since the identification information is information for the mobile terminal to identify the cell of the base station to which the mobile terminal is connected, the identification information of one cell and the identification information of the adjacent cell adjacent to the one cell are set so as not to match as much as possible. Is desirable. Conventionally, such identification information has been set based on the power level of the radio signal, the cell layout, the distance between base stations, and the like (see, for example, Patent Documents 1 and 2).

Japanese Patent No. 6026673 Japanese Patent No. 6037588

Conventionally, for example, it is set to raise the optimization priority from cells having a larger overlapping area of one cell and adjacent cells adjacent to the one cell, and to make the identification information different from the combination with the higher priority. However, the area between cells where the identification information overlaps was reduced. However, when the number of base stations for which identification information should be set increases, the time required for setting increases, and it may become impossible in reality to end the process.

Therefore, the present invention has been made in view of these points, and an object of the present invention is to provide a setting device, a mobile terminal system, a setting method, and a program capable of setting identification information for identifying a cell of a base station at high speed. To do.

In the first aspect of the present invention, a setting device for setting identification information for a mobile terminal to identify a cell of a base station to be connected, and an acquisition unit for acquiring arrangement information of a plurality of base stations. Based on the arrangement information and the arrangement of the selected plurality of target base stations, the reception unit that receives the selection result of the plurality of target base stations having the cell for which the identification information should be set among the plurality of base stations. A division unit that divides the plurality of base stations into a plurality of clusters, and an information setting control unit that sets the identification information of the selected cell of the plurality of target base stations for each of the divided clusters. The identification information is calculated as MOD (m, n), where m is the value of the physical cell identifier (PCI) assigned to each of the cells and n is the number of the cells possessed by each of the plurality of base stations. Provide a setting device.

The acquisition unit further acquires handover relation (HOR) information indicating the number of handover attempts that have occurred between each of the cells of the plurality of base stations and adjacent cells adjacent to each of the cells. The division unit may divide the plurality of base stations into the plurality of clusters based on the HOR information between one base station and another base station among the plurality of base stations.

In the division unit, the total number of handover trials generated between the first base station and the second base station is between the first base station and each base station other than the second base station. If it is larger than the total number of handover trials that have occurred, the first base station and the second base station may be included in one cluster.

The division unit determines the presence / absence of a flow line of the user of the mobile terminal based on the total number of handover trials generated between one base station and another base station, and the presence / absence of the flow line. The plurality of base stations may be divided into the plurality of clusters based on the above.

The information setting control unit may set the identification information of the selected cell for each of the clusters in an order based on the total number of handover trials generated in each of the clusters.

When the information setting control unit sets the identification information of the selected cell in one cluster among the plurality of clusters, the information setting control unit uses the identified identification information after setting for the selected cell in the one cluster. Then, the identification information of the selected cell in the next cluster may be set.

The information setting control unit may have an update unit that updates the identification information of the selected cell based on the combination of the HOR information, the identification information of the selected cell, and the identification information of the adjacent cell. Good.

The update unit allocates the corresponding number of handover attempts to all the configurable combinations of the identification information of the selected cell and the identification information of the adjacent cell, and all the configurable identification information. Of the combinations, the total number of handover attempts assigned to the combination in which the identification information of the selected cell and the identification information of the adjacent cell match, and the ratio of all the handover attempts are duplicated. It may have a calculation unit calculated as a rate and a determination unit for determining the identification information of the selected cell to be updated based on the duplication rate.

When the first cell becomes inaccessible to the mobile terminal, the reception unit sets the first cell and one or more of the cells adjacent to the first cell as one second cell, and the first cell. The selection cell including the two cells is accepted, the acquisition unit further acquires the HOR information corresponding to the selection cell including the second cell, and the information setting control unit includes the second cell. The identification information of the cluster in which the selected cell is arranged may be set.

When the first cell, which has been in a connectable state, returns to a state in which it can be connected to the mobile terminal, the reception unit excludes the second cell from the selected cell and adds the first cell. The selected cell is received, the acquisition unit further acquires the HOR information corresponding to the selected cell to which the first cell is added, and the information setting control unit further acquires the selected cell to which the first cell is added. The identification information of the cluster in which the is arranged may be set.

The setting device may further include a PCI setting unit that sets a value of the PCI assigned to each of the selected cells based on the updated identification information.

In the second aspect of the present invention, the mobile terminal, the plurality of base stations to which the mobile terminal is connected, and the identification information for the mobile terminal to identify the cells of the plurality of base stations are provided. Provided is a mobile terminal system including the setting device of the first aspect to be set.

In the third aspect of the present invention, there is a setting method for setting identification information for the mobile terminal to identify cells of a plurality of base stations to be connected, and a step of acquiring the arrangement information of the plurality of base stations. Based on the step of accepting the selection result of a plurality of target base stations having the cell for which the identification information should be set among the plurality of base stations, and the arrangement information and the arrangement of the plurality of target base stations. A step of dividing a plurality of base stations into a plurality of clusters and a step of setting the identification information of a selected cell possessed by the plurality of target base stations are provided for each of the divided clusters, and the identification information is the cell. Provided is a setting method calculated as MOD (m, n), where m is the value of the physical cell identifier (PCI) assigned to each of the above cells and n is the number of the cells possessed by each of the plurality of base stations. To do.

In a fourth aspect of the present invention, there is provided a program that, when executed by a computer, causes the computer to function as the setting device of the first aspect.

According to the present invention, there is an effect that the identification information for identifying the cell of the base station can be set at high speed.

A configuration example of the mobile terminal system S according to the present embodiment is shown. A first configuration example of the setting device 100 according to the present embodiment is shown. An example of the operation flow of the setting device 100 according to this embodiment is shown. An example of the information of the base station 10 received by the reception unit 110 according to the present embodiment is shown. A first example is shown in which the allocation unit 142 according to the present embodiment allocates the number of handover attempts to one combination of the identification information of the selected cell and the identification information of the adjacent cell. A second example is shown in which the allocation unit 142 according to the present embodiment allocates the number of handover attempts to one combination of the identification information of the selected cell and the identification information of the adjacent cell. An example of the result of calculating the duplication rate by the calculation unit 144 according to the present embodiment is shown. A second configuration example of the setting device 100 according to the present embodiment is shown. A third configuration example of the setting device 100 according to the present embodiment is shown. An example of the operation flow of the setting device 100 of the third configuration example is shown. An example is shown in which the division unit 310 according to the present embodiment divides a plurality of base stations 10 into a plurality of clusters.

<Configuration example of mobile terminal system S>
FIG. 1 shows a configuration example of the mobile terminal system S according to the present embodiment. The mobile terminal system S includes a base station 10, a mobile terminal 20, and a setting device 100. The base station 10 is provided with an antenna and transmits radio waves to the mobile terminal 20. A plurality of base stations 10 are provided outdoors or indoors, and the range in which radio waves reach the mobile terminal 20 from the plurality of base stations 10 is a communicable area. The mobile terminal 20 is a communicable device such as a mobile phone, a smartphone, a game device, a tablet PC, a small PC, a notebook PC, or the like.

The communicable range of each base station 10 is determined by the transmission power level, the arrangement of buildings, and the like. Further, the communicable range of the base station 10 is divided into a plurality of cells 12. That is, the plurality of cells 12 are spread in a communicable area. Further, the adjacent cells 12 may be arranged so as to partially overlap each other. It is desirable that the number n of cells 12 included in one base station 10 is predetermined. In the present embodiment, an example in which each base station 10 has three cells 12 will be described (n = 3).

A physical cell identifier (PCI: Physical Cell ID) is assigned to each of the plurality of cells 12 in advance. For example, in LTE and the like, one of 504 PCIs of numbers 0 to 503 is assigned to each of the plurality of cells 12. Each base station 10 has, for example, n cells 12 to which consecutive numbered PCIs are assigned. FIG. 1 shows an example in which base station 10a has cells 12a, 12b, and 12c to which numbers 102, 103, and 104 are assigned, respectively.

The base station 10 transmits a reference signal to each of the cells 12 to which such a PCI is assigned. The base station 10 switches the cell 12 to which the reference signal is transmitted at a predetermined period. For example, the base station 10 switches the transmission destination of the reference signal in ascending order of the value of the remainder number MOD (m, n) obtained by dividing the value m of the PCI by the number n of the cell 12.

In the case of the example of FIG. 1, the MOD (m, n) of the cell 12a has a PCI number 102, so MOD (102, 3) = 0. Further, the cell 12b has a MOD (103, 3) = 1, and the cell 12c has a MOD (104, 3) = 2. Therefore, the base station 10 transmits the reference signal in the order of cell 12a, cell 12b, and cell 12c. Further, the base station 10 repeats the transmission of the reference signal to the three cells 12 at regular intervals.

As described above, since the base station 10 transmits the reference signal by changing the time zone for each cell 12, the mobile terminal 20 identifies the cell 12 of the base station 10 by receiving the reference signal. Can be done. For example, when the user who owns the mobile terminal 20 is in the cell 12b of the base station 10a, the mobile terminal 20 receives the reference signal during the period corresponding to MOD (103, 3) = 1.

Then, when the user moves in the direction of the cell 12d of the base station 10b, the reference signal is received even during the period corresponding to MOD (72,3) = 0, and it is identified that the user is moving to a different cell 12. it can. As a result, the mobile terminal 20 can switch the connection from the base station 10a that was communicating to the base station 10b of the movement destination as the user moves. The operation in which the mobile terminal 20 switches the base station 10 to be connected while the user is moving in this way is called a handover. In addition to the reference signal transmission period, the base station 10 may change the frequency of the reference signal, but in the present embodiment, it is assumed that the frequency of the reference signal is constant.

As described above, when the value of PCI assigned to each of the cells 12 is m and the number of cells 12 of each of the base stations 10 is n, the value calculated as MOD (m, n) is the cell. It is used as identification information for identifying 12. Therefore, it is desirable that the identification information of the adjacent cells 12 is preset so as to have different values from each other. In particular, it is desirable that the identification information of the plurality of cells 12 arranged on the movement line on which the user moves is set to different values.

For example, if the reference signals of the same frequency are used and the identification information of the adjacent cells 12 is the same, the mobile terminal 20 may fail in the handover and cause a call disconnection or the like. Further, if the reference signals are received from different base stations 10 in the same time zone, the plurality of reference signals interfere with each other, so that the signal-to-interference noise ratio (SINR) deteriorates. When one base station 10 has three cells 12, such matching of identification information between adjacent cells 12 is called MOD3 duplication.

Conventionally, such identification information has been set based on the power level of the radio signal, the layout of the cell 12, the distance between base stations, and the like. In addition, the identification information may be set based on the size of the overlap between the cell 12 and the adjacent cell of the cell 12. However, the place where the user actually moves between two different cells and the handover occurs depends on the number of users, the arrangement of the flow lines on which the users move, and the like, and therefore has nothing to do with the arrangement of the cells 12. It is distributed in. In addition, the movement of the user may change significantly depending on the time of day, such as the time of commuting to work or school.

Therefore, even if the identification information is set as in the conventional case, the two cells 12 in which the MOD3 overlaps and the flow line to which many users move match, and many users use the hand of the mobile terminal 20. It was sometimes affected by deterioration of communication quality such as failure of over. Therefore, the setting device 100 according to the present embodiment appropriately sets the identification information in consideration of the number of handover trials that occur with the actual movement of the user. Such a setting device 100 will be described below.

<Configuration example of setting device 100>
FIG. 2 shows a first configuration example of the setting device 100 according to the present embodiment. The setting device 100 sets identification information for the mobile terminal 20 to identify the cell of the base station 10 to be connected. Further, the setting device 100 may further set the value of PCI based on the identification information. The setting device 100 is, for example, a computer such as a server. The setting device 100 includes a reception unit 110, an acquisition unit 120, a storage unit 130, an update unit 140, and a PCI setting unit 150.

The reception unit 110 receives the selection result of the base station 10 having the cell 12 for which the identification information should be set. The cell 12 for which the identification information should be set is, for example, a cell 12 whose identification information matches that of the adjacent cell 12. As an example, if the identification information of adjacent cells A and B match, base station A with cell A and / or base station B with cell B is selected as base station 10 for which MOD3 duplication is desired to be improved. To.

The operator or the like of the setting device may confirm the identification information and execute the selection of the base station 10, and instead, the CPU or the like automatically detects and executes the MOD3 duplication from the set identification information. You may. The reception unit 110 receives the information of the base station 10 selected in this way. The setting device 100 sets the identification information of the cell 12 included in the selected base station 10. Here, all cells 12 included in the selected base station 10 are designated as selected cells.

The acquisition unit 120 acquires handover relation (HOR) information indicating the number of handover attempts that have occurred between each of the selected cells of the selected base station 10 and the adjacent cells adjacent to each of the selected cells. .. The acquisition unit 120 acquires, for example, HOR information for a reference signal having the same frequency in all the selected base stations 10.

The HOR information includes information on the number of specific messages communicated between the base station 10 and the mobile terminal 20 when the mobile terminal 20 is handed over. For example, when the mobile terminal 20 in one cell 12 approaches an adjacent cell adjacent to the one cell 12 and receives a reference signal of the adjacent cell, the mobile terminal 20 receives the reference signal to the base station 10 having the adjacent cell. Send a "Measurement Report" message with signal quality information.

The base station 10 having an adjacent cell transmits an "RRC Connection Reconfiguration" message instructing the handover to the mobile terminal 20 according to the quality information. Here, the base station 10 stores the number of times the "RRC Connection Reconfiguration" message is transmitted as the number of times of attempt information. Then, the mobile terminal 20 hands over to the adjacent base station 10 in response to the handover instruction, and if the handover is successful, transmits a "RRC Connection Reconfiguration Complete" message to the handed over base station 10. Here, the base station 10 stores the number of times the "RRC Connection Reconfiguration Complete" message is received as the number of times of success information.

The HOR information includes the number of such attempt information, the number of success information, and the like. Since the mobile terminal 20 hands over based on the quality of the reference signal received from the base station 10, the number of attempt information and the number of success information are almost the same. Therefore, the number of handover attempts acquired by the acquisition unit 120 is the number of success information transmitted from the mobile terminal 20 to the base station 10 and the attempt transmitted from the base station 10 to the mobile terminal 20 included in the HOR information. Either one of the number of times of information is acceptable.

The acquisition unit 120 acquires such HOR information from the base station 10. The acquisition unit 120 accesses, for example, a base station 10 or a system including the base station 10 via a network. Further, the acquisition unit 120 may acquire HOR information from an external database 30 or the like. The acquisition unit 120 acquires, for example, HOR information generated in a predetermined period. Further, the acquisition unit 120 may further acquire the identification information set in the selected cell and the adjacent cell adjacent to the selected cell.

The storage unit 130 stores the HOR information acquired by the acquisition unit 120. The storage unit 130 may store the information of the base station 10 and the selected cell received by the reception unit 110. Further, the storage unit 130 may store the identification information set in the selected cell and the adjacent cell, respectively. The storage unit 130 may store intermediate data, calculation results, threshold values, parameters, and the like generated (or used) by the setting device 100 in the process of operation. Further, the storage unit 130 may supply the stored data to the request source in response to the request of each unit in the setting device 100.

The storage unit 130 may store information on an OS (Operating System) in which a server or the like functions as a setting device 100, and a program. In addition, the storage unit 130 may store various information including a database referred to when the program is executed. For example, a computer such as a server functions as at least a part of a reception unit 110, an acquisition unit 120, a storage unit 130, an update unit 140, and a PCI setting unit 150 by executing a program stored in the storage unit 130. ..

The storage unit 130 includes, for example, a ROM (Read Only Memory) for storing a BIOS (Basic Input Output System) of a computer or the like, and a RAM (Random Access Memory) serving as a work area. Further, the storage unit 130 may include a large-capacity storage device such as an HDD (Hard Disk Drive) and / or an SSD (Solid State Drive). Further, the computer may further include a GPU (Graphics Processing Unit) and the like.

The update unit 140 updates the identification information of the selected cell based on the combination of the HOR information, the identification information of the selected cell, and the identification information of the adjacent cell. The update unit 140 has an allocation unit 142, a calculation unit 144, and a determination unit 146.

The allocation unit 142 allocates the corresponding number of handover attempts to all the configurable combinations of the identification information of the selected cell and the identification information of the adjacent cell. For example, when any one of 0, 1, and 2 is set as the identification information in the three selection cells of one base station 10, the set of identification information that can be set in the selection cell is 3! = There are 6 ways. The allocation unit 142 allocates the corresponding number of handover attempts for each combination of the six types of identification information sets of the selected cell and the identification information of the adjacent cell.

Based on the number of handover attempts assigned by the allocation unit 142, the calculation unit 144 calculates the rate at which the number of handover attempts occurs in the combination of the selected cell and the adjacent cell in which the identification information is duplicated, as the duplication rate. .. The calculation unit 144 calculates the duplication rate for each set of identification information that can be set in the selected cell.

The determination unit 146 determines the identification information of the selected cell to be updated based on the duplication rate. The determination unit 146 determines, for example, the set of identification information having the smallest duplication rate as the identification information of the selected cell to be updated. Further, even when there are a plurality of selected base stations 10, the determination unit 146 identifies the selected cell to be updated with the identification information set having the smallest duplication rate among the identification information sets of all the selected cells. It may be determined as information.

The PCI setting unit 150 sets the value of PCI assigned to each of the selected cells based on the updated identification information. The PCI setting unit 150 sets the values of numbers 0 to 503 in the selection cell, for example, based on the identification information. The PCI setting unit 150 accesses the base station 10 or a system including the base station 10 via a network, for example, and sets the value of the PCI. Further, the PCI setting unit 150 may store the value of the PCI in an external database 30 or the like. In this case, the base station 10 or the system including the base station 10 reads the value of PCI from the external database 30 or the like and updates the PCI of the selected cell.

Since the setting device 100 according to the present embodiment sets the identification information of the selected cell based on the number of handover trials actually generated, the number of users, the flow line, and the like can be reflected in the identification information. .. As a result, the mobile terminal system S can reduce the number of users affected by the deterioration of communication quality by appropriately setting the identification information of the selected cell by the setting device 100. The operation of such a setting device 100 will be described below.

<Operation flow of setting device 100>
FIG. 3 shows an example of the operation flow of the setting device 100 according to the present embodiment. The setting device 100 sets the identification information of the selected cell by executing the operations S310 to S360 of FIG.

First, the reception unit 110 receives the selection result of the base station 10 having the cell 12 for which the identification information should be set (S310). The reception unit 110 receives the selection results of one or more base stations 10. In the present embodiment, an example in which the reception unit 110 receives the selection result of one base station 10 will be described.

FIG. 4 shows an example of information on the base station 10 received by the reception unit 110 according to the present embodiment. The base station 10 has three selection cells, a first selection cell 41, a second selection cell 42, and a third selection cell 43. The PCI of the selected cell is 102 for the first selected cell 41, 103 for the second selected cell 42, and 104 for the third selected cell 43. In this case, the identification information of the first selection cell 41 is 0, the identification information of the second selection cell 42 is 1, and the identification information of the third selection cell 43 is 2. The combination of such selected cells is referred to as identification information (0, 1, 2).

The adjacent cells of the first selected cell 41 are the first adjacent cell 51, the second adjacent cell 52, and the third adjacent cell 53. The identification information of the adjacent cells is 0 for the first adjacent cell 51, 1 for the second adjacent cell 52, and 2 for the third adjacent cell 53. The adjacent cells of the second selection cell 42 are the fourth adjacent cell 54, the fifth adjacent cell 55, and the sixth adjacent cell 56. The identification information of the adjacent cells is 0 for the 4th adjacent cell 54, 1 for the 5th adjacent cell 55, and 1 for the 6th adjacent cell 56. The adjacent cells of the third selection cell 43 are the seventh adjacent cell 57 and the eighth adjacent cell 58. The identification information of the adjacent cell is 0 for the 7th adjacent cell 57 and 2 for the 8th adjacent cell 58.

In this case, the first selected cell 41 and the first adjacent cell 51, the second selected cell 42 and the fifth adjacent cell 55 and the sixth adjacent cell 56, and the third selected cell 43 and the eighth adjacent cell 58 overlap MOD3. It has become. FIG. 4 shows the reception unit 110 when the identification information of the first selection cell 41, the second selection cell 42, and / or the third selection cell 43 is set as a cell in order to improve such MOD3 duplication. Is an example of the base station 10 accepted by.

Next, the acquisition unit 120 acquires HOR information between each of the selected cells of the selected base station 10 and the adjacent cells adjacent to each of the selected cells (S320). The acquisition unit 120 acquires, for example, HOR information generated in a predetermined period. Next, the allocation unit 142 allocates the corresponding number of handover attempts to all the configurable combinations of the identification information of the selected cell and the identification information of the adjacent cell (S330).

FIG. 5 shows a first example in which the allocation unit 142 according to the present embodiment allocates the number of handover attempts to one combination of the identification information of the selected cell and the identification information of the adjacent cell. FIG. 5 shows an example in which the identification information of the three selected cells is set as the already set identification information (0, 1, 2). The first column of FIG. 5 shows the selected cell, and the second column shows the identification information set in the selected cell. In addition, adjacent cells are shown in the third column, and identification information set in the adjacent cells is shown in the fourth column.

The fifth column shows the number of handover attempts that have occurred between the selected cell and the adjacent cell. For example, the number of handover attempts that occurred between the first selected cell 41 and the first adjacent cell 51 is 300, and the number of handover attempts that occurred between the second selected cell 42 and the fourth adjacent cell 54 is 80. is there. Further, the sixth column shows the number of handover attempts assigned to the MOD3 overlapping combination in which the identification information of the selected cell and the identification information of the adjacent cell match.

Since the cell 12 in which the identification information should be set is three selected cells, all the combinations in which the identification information of the selected cell and the identification information of the adjacent cell can be set are 3! = 6 ways, and there are 5 combinations in addition to the combinations shown in FIG. That is, the allocation unit 142 allocates the number of handover attempts to each of the five combinations in addition to one combination of the identification information of the selected cell and the identification information of the adjacent cell as shown in FIG.

Next, the calculation unit 144 calculates the duplication rate (S340). The calculation unit 144 includes the total number of handover attempts assigned to the combinations in which the identification information of the selected cell and the identification information of the adjacent cell match among all the combinations in which the identification information can be set, and all the handover attempts. The ratio to the number of times is calculated as the duplication rate. In the case of the example of FIG. 5, the total number of handover trials is 1000, and the total number of handover trials assigned to the combinations having MOD3 overlap is 500. Therefore, the calculation unit 144 calculates the duplication rate for the combination of the identification information (0, 1, 2) of the three selected cells and the identification information of the adjacent cells as 50%. The calculation unit 144 also calculates the duplication rate for other combinations.

FIG. 6 shows a second example in which the allocation unit 142 according to the present embodiment allocates the number of handover attempts to one combination of the identification information of the selected cell and the identification information of the adjacent cell. FIG. 6 shows an example of a combination of the identification information (0, 2, 1) of the three selected cells and the identification information of the adjacent cells, which is different from the combination of FIG.

Since the identification information of the selected cell shown in FIG. 6 is different from the identification information of the selected cell shown in FIG. 5, the MOD3 overlapping combination is different. For example, the adjacent cell having the identification information overlapping with the identification information 2 of the second selection cell 42 disappears, and the adjacent cell having the identification information overlapping with the identification information 1 of the third selection cell 43 also disappears. As a result, the calculation unit 144 calculates the duplication rate for the combination of the identification information (0,2,1) of the three selected cells and the identification information of the adjacent cells as 30%. In this way, the calculation unit 144 calculates the duplication rate for all the other combinations.

FIG. 7 shows an example of the result of calculating the duplication rate for all the combinations in which the identification information of the selected cell and the identification information of the adjacent cell can be set by the calculation unit 144 according to the present embodiment. FIG. 7 shows the six identification information (0,1,2), (0,2,1), (1,0,2), (1,2,0), (2,0,1) of the selected cell. , And (2,1,0), which is the result of the calculation unit 144 calculating the duplication rate, respectively.

Next, the determination unit 146 determines the identification information of the selected cell to be updated based on the duplication rate (S350). The determination unit 146 determines, for example, to update the identification information of the selected cell to the combination of the identification information of the selected cell having the smallest duplication rate. In the case of the example of FIG. 7, the determination unit 146 determines to update the identification information of the selected cell to the identification information (2,0,1) having a duplication rate of 17%.

Next, the PCI setting unit 150 sets the value of the PCI assigned to each of the selected cells based on the updated identification information (S360). The PCI setting unit 150 sets, for example, the PCI of the first selection cell 41 to 104, the PCI of the second selection cell 42 to 102, and the PCI of the third selection cell 43 to 103, respectively.

As described above, the setting device 100 according to the present embodiment determines the identification information of the cell 12 to be set based on the number of handover trials actually generated. Therefore, the setting device 100 improves the duplication of the identification information between the two cells 12 in which the number of users holding the mobile terminal 20 and the distribution of the flow lines of the users are high, and the handover failure occurs. Can be reduced. As a result, the setting device 100 can appropriately set the identification information for identifying the cell 12 of the base station 10 in consideration of the influence on the communication due to the duplication of the identification information.

The setting device 100 according to the above embodiment has described an example in which the identification information of the selected cell is updated by using the three cells 12 included in one base station 10 as the selected cell, but the present invention is limited to this. There is nothing. The setting device 100 receives, for example, the selection results of two or more k base stations 10, and sets 3k cells 12 included in the selected k base stations 10 as selection cells, and identifies information of the selection cells. May be updated.

In this case, the acquisition unit 120 acquires the HOR information between each of the 3k selected cells and the adjacent cells adjacent to each of the 3k selected cells. Then, the allocation unit 142 allocates the corresponding number of handover attempts to all the configurable combinations of the identification information of the 3k selected cells and the identification information of the adjacent cells.

The identification information of all the selected cells can be set for each selected cell included in one base station 10 by the number of all sets of selected cells included in the other base station 10. That is, the identification information of 3k selected cells can be set as many as (3!) ^K ways. Therefore, the allocation unit 142 allocates the corresponding number of handover attempts to the combination of the identification information of the selected cell and the identification information of the adjacent cell in (3!) ^K sets. As a result, the calculation unit 144 calculates the duplication rate for each combination, and the determination unit 146 determines the identification information of the selected cell to be updated based on the duplication rate. As described above, the setting device 100 can determine the identification information of the selected cells possessed by the plurality of base stations 10.

The number of users holding the mobile terminal 20 and the distribution of user flow lines may vary depending on the time of day. Therefore, the setting device 100 may set the identification information based on the number of handover trials that occur for each time zone. Such a setting device 100 will be described below.

<Second configuration example of setting device 100>
FIG. 8 shows a second configuration example of the setting device 100 according to the present embodiment. In the setting device 100 of the second configuration example, those substantially the same as the operation of the setting device 100 according to the present embodiment shown in FIG. 2 are designated by the same reference numerals, and the description thereof will be omitted. The setting device 100 of the second configuration example further includes a weighting unit 210 and a switching unit 220.

The weighting unit 210 calculates the total number of handover trials for each time zone, and weights the number of handover trials in the time zone when the total is maximum. The weighting unit 210 multiplies, for example, the number of handover trials in the time zone when the total number of handover trials is maximum by a weight of 1 or more. Further, the weighting unit 210 may multiply weights of different sizes in descending order of the total number of handover trials.

In addition, for example, when the HOR information includes the information of the time when the handover trial occurred, the weighting unit 210 calculates the total number of handover trials for each time zone based on the information of the time. Instead of this, the acquisition unit 120 may acquire the HOR information for each predetermined time zone. For example, the acquisition unit 120 acquires HOR information at regular time intervals, and stores the HOR information in the storage unit 130 in association with the acquisition time. As a result, the weighting unit 210 can calculate the total number of handover trials for each acquisition time of the acquisition unit 120.

Then, the allocation unit 142 allocates the corresponding weighted number of handover attempts to all the configurable combinations of the identification information of the selected cell and the identification information of the adjacent cell. As a result, the calculation unit 144 can calculate the duplication rate based on the weighted number of handover trials. Therefore, the determination unit 146 can determine the identification information of the selected cell in consideration of the time zone in which the number of users and the flow line of the users affect the communication as the identification information to be updated.

The weight by the weighting unit 210 is not limited to the weight based on the total number of handover attempts. The weighting unit 210 may give weights based on traffic information or the like. The traffic information is, for example, a value such as a downlink SINR and a throughput. In this case, the acquisition unit 120 may acquire communication traffic information from, for example, the mobile terminal 20. Further, the weighting unit 210 may give different weights to each combination of one selected cell and one adjacent cell.

Instead of this, the setting device 100 of the second configuration example may determine a plurality of identification information corresponding to a plurality of time zones in advance, and may switch the determined plurality of identification information according to the passage of time. In this case, the update unit 140 determines in advance the identification information of the selected cell for each of a plurality of time zones. The update unit 140 determines, for example, the identification information of the selected cell corresponding to the one time zone by using the HOR information of the one time zone acquired by the acquisition unit 120. Then, the update unit 140 determines the identification information of the selected cell corresponding to the other time zone by using the HOR information of the other time zone acquired by the acquisition unit 120. The storage unit 130 stores the identification information of the selected cell determined for each predetermined time zone in this way.

The switching unit 220 reads the identification information of the corresponding selected cell from the storage unit 130 at predetermined time intervals and switches the identification information as the identification information to be updated. The switching unit 220 supplies the corresponding identification information to the PCI setting unit 150, for example, at the time corresponding to the time zone in which the HOR information acquired by the acquisition unit 120 is generated. In this way, by switching the identification information with the passage of time, the setting device 100 can finely respond to the number of users and the distribution of the flow lines of the users, which fluctuate depending on the time zone, and can provide the identification information. It can be set more appropriately.

The setting device 100 according to the second configuration example described above has described an example in which the switching unit 220 switches the identification information with the passage of time, but the present invention is not limited to this. The setting device 100 may determine a plurality of identification information in advance and switch the identification information based on the traffic information or the like even in the same time zone. For example, the setting device 100 determines a plurality of identification information by weighting the HOR information acquired by the acquisition unit 120. When the weighting unit 210 uses a plurality of weight values, the updating unit 140 determines a plurality of identification information according to the weight values. The storage unit 130 stores a plurality of identification information determined in this way.

Then, the switching unit 220 selects and further switches the identification information to be updated based on the information acquired by the acquisition unit 120 after updating the identification information of the selected cell. For example, if the acquisition unit 120 acquires the traffic information from the mobile terminal 20 after the update unit 140 updates the identification information of the selected cell and the traffic state does not improve beyond the threshold value, the switching unit 220 weights. Switch to the identification information determined by making it different. As a result, the setting device 100 can set the identification information more appropriately in response to the change in the traffic state.

In the above embodiment, the setting device 100 has described an example in which the setting device 100 receives the selection result of the base station 10 having the cell 12 for which the identification information is to be set and updates the identification information of the selected cell of the base station 10. Here, the base station 10 having the cell 12 for which the identification information should be set is set as the target base station. Then, assuming that the number of selected cells included in one target base station is n, the identification information of n · k selected cells included in k target base stations is set as many as (n!) ^K ways. It will be possible. Therefore, as the number k of the target base stations increases, the amount of calculation required for processing by the setting device 100 increases exponentially.

Therefore, when the setting device 100 according to the present embodiment sets the identification information of the selected cells of a plurality of target base stations, it is divided into clusters of a plurality of base stations 10 including the target base stations, and the identification information is provided for each cluster. The amount of calculation may be reduced by setting. Such a setting device 100 will be described below.

<Third configuration example of setting device 100>
FIG. 9 shows a third configuration example of the setting device 100 according to the present embodiment. In the setting device 100 of the third configuration example, those substantially the same as the operation of the setting device 100 according to the present embodiment shown in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted. The setting device 100 of the third configuration example further includes a division unit 310 and an information setting control unit 320.

In the setting device 100 of the third configuration example, the acquisition unit 120 further acquires the arrangement information of the plurality of base stations 10. It is desirable that the acquisition unit 120 acquires the arrangement information of the base station 10 surrounding the target base station.

The division unit 310 divides a plurality of base stations into a plurality of clusters based on the arrangement information and the arrangement of the selected plurality of target base stations. The division unit 310 divides a plurality of base stations 10 so that, for example, one cluster includes a predetermined number or less of target base stations. Further, the division unit 310 may divide a plurality of base stations 10 into clusters of a predetermined number or less.

The information setting control unit 320 sets the identification information of the selected cells of the plurality of target base stations for each divided cluster. The information setting control unit 320 sets the identification information of the selected cell for each cluster in a predetermined order. The information setting control unit 320 has an update unit 140. The operation of the setting device 100 of the above third configuration example will be described below.

FIG. 10 shows an example of the operation flow of the setting device 100 of the third configuration example. The setting device 100 sets the identification information of the selected cells possessed by the plurality of target base stations by executing the operations S410 to S470 of FIG.

First, the reception unit 110 receives the selection result of a plurality of target base stations having the cell 12 for which the identification information should be set among the plurality of base stations 10 (S410). The reception unit 110 receives the selection results of two or more base stations 10. The selected base station 10 is set as the target base station. As shown in FIG. 4, the information of the target base station is the PCI of the selected cell possessed by the target base station, the identification information, the identification information of the adjacent cell adjacent to the selected cell, and the like.

Next, the acquisition unit 120 acquires the arrangement information of the base station 10 including the plurality of target base stations (S420). The acquisition unit 120 acquires, for example, the arrangement information of all the base stations 10 adjacent to each of the target base stations. Further, the acquisition unit 120 may acquire the arrangement information of all the base stations 10.

Next, the acquisition unit 120 acquires the HOR information generated in the base station 10 included in the acquired arrangement information (S430). The acquisition unit acquires HOR information indicating the number of handover attempts that have occurred between each of the cells 12 of the plurality of base stations 10 included in the arrangement information and the adjacent cells adjacent to each of the cells 12. To do. The acquisition unit 120 acquires, for example, HOR information generated in a predetermined period.

Next, the division unit 310 divides the plurality of base stations 10 into a plurality of clusters based on the arrangement information and the arrangement of the plurality of target base stations (S440). The division unit 310 divides a plurality of base stations 10 so that, for example, one cluster includes a predetermined number of target base stations. Further, the division unit 310 further divides the plurality of base stations 10 into a plurality of clusters based on the HOR information between one base station 10 and the other base station 10 among the plurality of base stations 10.

FIG. 11 shows an example in which the division unit 310 according to the present embodiment divides a plurality of base stations 10 into a plurality of clusters. FIG. 11 shows an example in which the division unit 310 divides the 42 base stations 10 into three clusters, the first cluster 61, the second cluster 62, and the third cluster 63. The area where the base station 10 transmits the reference signal is schematically shown by a hexagon, and the reference numeral of the base station 10 is attached. Further, an example will be shown in which the first cluster 61 includes one, the second cluster 62 contains three, and the third cluster 63 includes four, for a total of eight target base stations 70. The area where the target base station 70 transmits the reference signal is schematically shown by diagonal lines, and the target base station 70 is designated by a reference numeral.

As described above, for example, when 3 the number of selected cells in a single target base station, the identity of the 24 selected cell included in the eight target base station 70, 6 ^eight (= 1,679,616) Can be set as many as the number of. However, when the division unit 310 divides into three clusters and sets the identification information for each cluster, the number of the identification information of the selected cells that can be set is 6 ¹ (= 6) and 6 ³ (= 216). ), and ⁶ becomes 1,518 ways by the sum of the ^four ways (= 1,296). That is, even in the example shown in FIG. 11, it can be seen that the processing of the setting device 100 can be reduced to 1/1000 or less.

Since the identification information is set for each cluster, it is desirable to reduce the influence of the identification information setting of one cluster on the identification information setting of the other cluster. In this case, it is desirable that the division unit 310 provide a cluster boundary so as not to divide the user's flow line or the like. Therefore, the division unit 310 divides the plurality of base stations 10 into a plurality of clusters based on the HOR information.

In the division unit 310, for example, the total number of handover attempts generated between the first base station and the second base station is generated between the first base station and each base station other than the second base station. If it is larger than the total number of handover attempts, the first base station and the second base station are included in one cluster. In this way, by including the set of base stations 10 in which the number of handover trials is large in one cluster, the division unit 310 can prevent the boundary of the cluster from dividing the flow line of the user.

If the user's flow line is a complicated route, and / or if the user's flow line is long, it may be difficult to divide into clusters. In this case, the division unit 310 determines whether or not there is a flow line of the user of the mobile terminal 20 based on the total number of handover trials that have occurred between one base station 10 and the other base station 10. A plurality of base stations 10 may be divided into a plurality of clusters based on the presence or absence of a flow line.

For example, when the number of handover attempts equal to or greater than the threshold value occurs between the two cells 12, the division unit 310 determines that there is a flow line of the user between the two cells 12. Then, the division unit 310 divides a plurality of base stations 10 so that one cluster includes such a flow line.

Further, when such flow lines are so continuous that it becomes difficult to include them in one cluster, the division unit 310 sets the boundary of the cluster between the base stations 10 having a smaller total number of handover attempts in the flow lines. It may be provided. Further, the division unit 310 may display the result of determining the user's flow line to the operator or the like to provide a cluster boundary according to the operator's input. As a result, the influence of the identification information setting by one cluster on the identification information setting of other clusters can be reduced, and even if the identification information is sequentially set for each cluster, the identification information of the entire cluster is optimized. Can be optimized.

Next, the information setting control unit 320 sets the identification information of the selected cells of the plurality of target base stations 70 for each divided cluster (S450, S460). Here, it is desirable that the information setting control unit 320 sets the identification information of each cluster in a predetermined order. For example, the information setting control unit 320 sets the identification information in ascending order of the number of target base stations 70 included in the cluster. In this case, the information setting control unit 320 sets the identification information of the selected cells included in the cluster in the order of, for example, the first cluster 61, the second cluster 62, and the third cluster 63. In this way, the information setting control unit 320 can efficiently execute the optimization of the entire cluster by leaving the order of the clusters having many combinations of identification information settings and having a high degree of freedom in setting.

Further, the information setting control unit 320 may set the identification information of the selected cell for each cluster in the order based on the total number of handover attempts generated in each cluster. In this case, the information setting control unit 320 sets the identification information of the selected cells in descending order of the total number of handover trials, for example. In this way, the information setting control unit 320 optimizes the clusters that have a large impact on the user under conditions with few restrictions by first ordering the clusters and the like that are more desirable to be optimized due to the large number of handover attempts. Can be optimized.

The setting of the identification information of the selected cell in each cluster can be executed as already described in FIG. 3 (S460). For example, the allocation unit 142 allocates the corresponding number of handover attempts to all the configurable combinations of the identification information of the selected cell and the identification information of the adjacent cell. Next, the calculation unit 144 calculates the duplication rate. Next, the determination unit 146 determines the identification information of the selected cell to be updated based on the duplication rate.

Here, when the information setting control unit 320 sets the identification information of the selected cell in one cluster among the plurality of clusters, the information setting control unit 320 uses the set identification information in the selected cell in the one cluster. Set the identification information of the selected cell in the next cluster. In this way, the information setting control unit 320 sequentially updates the identification information of each cluster until the setting of the identification information of all the clusters is completed.

Next, the PCI setting unit 150 sets the value of the PCI assigned to each of the selected cells based on the updated identification information (S470). As described above, the setting device 100 of the third configuration example divides a plurality of base stations 10 into clusters, and determines the identification information of the selected cell to be set for each cluster. As a result, the setting device 100 can determine the identification information of the cell 12 at a higher speed.

Further, for example, when the subject base station 70 is 100 or more, the combination of the identification information is generated in ways ^{6 100 (≒ 6.5 × 10 77} ), in practice computation becomes impossible. Even in this case, setting unit 100, for example, to include one cluster into five target base station 70, by dividing the plurality of base stations 10 to 20 clusters, 20 × 6 ⁵ kinds ( The identification information can be set appropriately by reducing the number of identification information combinations to about 1.6 × 10 ⁵ ).

In the above embodiment, the setting device 100 has described an example in which the setting device 100 receives the selection result of the base station 10 having the cell 12 for which the identification information is to be set and updates the identification information of the selected cell of the base station 10. , Not limited to this. The setting device 100 may receive information that the configuration of the plurality of cells 12 has changed due to the occurrence of, for example, a failure.

As an example, when the first cell becomes inaccessible to the mobile terminal 20, one or a plurality of cells 12 adjacent to the first cell become an area for communicating with the mobile terminal 20 instead of the first cell. That is, the base station 10 including one or a plurality of cells 12 adjacent to the first cell switches so as to transmit the reference signal to the first cell. The reception unit 110 receives such an operation of the base station 10. The reception unit 110, for example, sets the first cell and one or a plurality of cells 12 adjacent to the first cell as one second cell, and receives a selected cell including the second cell.

Then, the acquisition unit 120 further acquires the HOR information corresponding to the selected cell including the second cell. That is, the acquisition unit 120 acquires the HOR information which is the result of the base station 10 exchanging information with the mobile terminal 20 after changing the configuration of the cell 12 in response to the failure caused by the base station 10. Based on such HOR information, the information setting control unit 320 sets the identification information of the cluster in which the selected cells including the second cell are arranged. That is, the update unit 140 updates the identification information corresponding to the selected cells including the second cell of the cluster.

As described above, the setting device 100 receives that the configuration of the cell 12 has changed due to a failure or the like, and acquires the HOR information after the configuration has changed to determine and update the corresponding identification information. Can be done. Since such a failure can be recovered by repair or the like, it is desirable that the setting device 100 can also recover from the failure.

For example, when the first cell, which has been in a connectable state, returns to a state in which it can be connected to the mobile terminal 20, the configuration of the plurality of cells 12 returns to the original state. Therefore, the reception unit 110 excludes the second cell from the selected cells and accepts the selected cell to which the first cell is added in response to the restoration of the base station 10. Then, the acquisition unit 120 further acquires the HOR information corresponding to the selected cell to which the first cell is added. As a result, the information setting control unit 320 sets the identification information of the cluster in which the selected cell to which the first cell is added is arranged. That is, the update unit 140 updates the identification information corresponding to the selected cell to which the first cell of the cluster is added.

As described above, the setting device 100 can determine and update the corresponding identification information by receiving the change in the configuration of the cell 12 and acquiring the HOR information after the configuration has changed. Therefore, the setting device 100 can change the changed cell 12 even if the configuration of the cell 12 spread in the communicable area changes due to the installation, movement, disposal, etc. of the new base station 10 not limited to the failure. The identification information can be updated as a selected cell.

In the above embodiment, it has been described that the setting device 100 divides a plurality of base stations 10 into clusters and determines the identification information of the selected cell to be set for each cluster. Then, the example in which the update unit 140 sets the identification information of the selected cell based on the HOR information has been described, but the present invention is not limited to this. Since the setting device 100 can set the identification information at a higher speed by dividing the plurality of base stations 10 into clusters by the division unit 310, the identification information of the selected cell is set by a known setting method. May be good.

Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes can be made within the scope of the gist. is there. For example, all or part of the device can be functionally or physically distributed / integrated in any unit. Also included in the embodiments of the present invention are new embodiments resulting from any combination of the plurality of embodiments. The effect of the new embodiment produced by the combination has the effect of the original embodiment.

10 Base station 12 Cell 20 Mobile terminal 30 Database 41 1st selection cell 42 2nd selection cell 43 3rd selection cell 51 1st adjacent cell 52 2nd adjacent cell 53 3rd adjacent cell 54 4th adjacent cell 55 5th adjacent cell 56 6th adjacent cell 57 7th adjacent cell 58 8th adjacent cell 61 1st cluster 62 2nd cluster 63 3rd cluster 70 Target base station 100 Setting device 110 Reception unit 120 Acquisition unit 130 Storage unit 140 Update unit 142 Allocation unit 144 Calculation unit 146 Decision unit 150 PCI setting unit 210 Weighting unit 220 Switching unit 310 Dividing unit 320 Information setting control unit

Claims (14)

It is a setting device that sets identification information for the mobile terminal to identify the cell of the base station to which it is connected.
An acquisition unit that acquires placement information for multiple base stations,
A reception unit that receives selection results of a plurality of target base stations having the cell for which the identification information should be set among the plurality of base stations.
A division unit that divides the plurality of base stations into a plurality of clusters based on the arrangement information and the arrangement of the plurality of target base stations selected.
Each of the divided clusters is provided with an information setting control unit for setting the identification information of the selected cells of the plurality of target base stations.
The identification information is calculated as MOD (m, n), where m is the value of the physical cell identifier (PCI) assigned to each of the cells and n is the number of the cells possessed by each of the plurality of base stations. Set device. The acquisition unit further acquires handover relation (HOR) information indicating the number of handover attempts that have occurred between each of the cells of the plurality of base stations and adjacent cells adjacent to each of the cells. ,
The division unit divides the plurality of base stations into the plurality of clusters based on the HOR information between one base station and another base station among the plurality of base stations.
The setting device according to claim 1. In the division unit, the total number of handover trials generated between the first base station and the second base station is between the first base station and each base station other than the second base station. The setting device according to claim 2, wherein the first base station and the second base station are included in one cluster when the total number of occurrences of the handover trials is larger than the total. The division unit determines the presence / absence of a flow line of the user of the mobile terminal based on the total number of handover trials generated between one base station and another base station, and the presence / absence of the flow line. The setting device according to claim 2 or 3, wherein the plurality of base stations are divided into the plurality of clusters based on the above. Any one of claims 2 to 4, wherein the information setting control unit sets the identification information of the selected cell for each cluster in an order based on the total number of handover trials generated in each of the clusters. The setting device described in the section. When the information setting control unit sets the identification information of the selected cell in one cluster among the plurality of clusters, the information setting control unit uses the identified identification information after setting for the selected cell in the one cluster. The setting device according to any one of claims 2 to 5, wherein the identification information of the selected cell in the next cluster is set. The information setting control unit has an update unit that updates the identification information of the selected cell based on the combination of the HOR information, the identification information of the selected cell, and the identification information of the adjacent cell. The setting device according to any one of 2 to 6. The update part
An allocation unit that allocates the corresponding number of handover attempts to all the configurable combinations of the identification information of the selected cell and the identification information of the adjacent cell.
Of all the combinations in which the identification information can be set, the total number of handover attempts assigned to the combination in which the identification information of the selected cell and the identification information of the adjacent cell match, and all the hands. A calculation unit that calculates the ratio to the number of overtrials as the duplication rate,
The setting device according to claim 7, further comprising a determination unit that determines the identification information of the selected cell to be updated based on the duplication rate. When the first cell becomes unable to connect to the mobile terminal,
The reception unit receives the selected cell including the second cell, with the first cell and one or more of the cells adjacent to the first cell as one second cell.
The acquisition unit further acquires the HOR information corresponding to the selected cell including the second cell, and further acquires the HOR information.
The information setting control unit sets the identification information of the cluster in which the selected cell including the second cell is arranged.
The setting device according to any one of claims 2 to 8. When the first cell, which has been in a connectable state, returns to a connectable state with the mobile terminal,
The receiving unit excludes the second cell from the selected cell and accepts the selected cell to which the first cell is added.
The acquisition unit further acquires the HOR information corresponding to the selected cell to which the first cell is added.
The information setting control unit sets the identification information of the cluster in which the selected cell to which the first cell is added is arranged.
The setting device according to claim 9. The setting device according to any one of claims 1 to 10, further comprising a PCI setting unit for setting a value of the PCI assigned to each of the selected cells based on the updated identification information. With the mobile terminal
With the plurality of base stations to which the mobile terminal is connected,
A mobile terminal system comprising the setting device according to any one of claims 1 to 11, wherein the mobile terminal sets the identification information for identifying the cells of the plurality of base stations. It is a setting method for setting identification information for a mobile terminal to identify cells of a plurality of base stations to be connected.
The step of acquiring the arrangement information of the plurality of base stations and
Among the plurality of base stations, a step of accepting selection results of a plurality of target base stations having the cell for which the identification information should be set, and
A step of dividing the plurality of base stations into a plurality of clusters based on the arrangement information and the arrangement of the plurality of target base stations, and
For each of the divided clusters, a step of setting the identification information of the selected cell possessed by the plurality of target base stations is provided.
The identification information is calculated as MOD (m, n), where m is the value of the physical cell identifier (PCI) assigned to each of the cells and n is the number of the cells possessed by each of the plurality of base stations. How to set up. A program that, when executed by a computer, causes the computer to function as the setting device according to any one of claims 1 to 11.

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