KR101548229B1 - Method managing cell and apparatus therefor - Google Patents

Abstract

The present invention relates to a cell management method and a device thereof. The cell management method is used to reset the physical cell identity (PCI) of a cell to enhance the quality of a mobile communication service. According to the present invention, the method, which is for managing cells to enhance the communication quality in a communication system, includes the steps of: collecting the data generated in each cell; extracting the data relevant to a serving cell from the collected data; calculating at least one of the average collision rate of the serving cell or the collision rate of each target cell having the same reference value as the serving cell; selecting one of the reference values different from the reference value of the serving cell as a modification target reference value when the calculated collision rate of the serving cell or one of the calculated collision rates of the target cells exceeds a threshold value; selecting one of the PCI units generating the modification target reference value as a modification target PCI unit; and resetting the PCI of the serving cell based on the selected PCI unit.

Description

[0001] METHOD MANAGING CELL AND APPARATUS THEREFOR [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a cell management method in a communication system, and more particularly, to a cell management method for resetting a cell PCI (Physical Cell Identity) to improve the quality of a mobile communication service and an apparatus therefor.

Due to the development of the mobile communication network, the terminal and the mobile communication network, the LTE (Long Term Evolution) network, which is a fourth generation mobile communication network, is commercialized and users are receiving communication services using the LTE network.

The LTE network forms a cell through an eNB (Enabled NodeB), and provides a communication service. Also, the eNB is given a PCI (Physical Cell Identity) for identifying the cell.

The PCI is a parameter for identifying a cell, which is set when the base station is initially installed, and the number is limited to 504. Due to this limited number of PCIs, PCI is reused in the range where there is no PCI conflict between cells of the week. The 3rd Generation Partnership Project (3GPP), which is an international standard organization, suggests that, within the range covered by a specific cell, a cell having the same PCI as the PCI of the cell should not exist in the vicinity.

In addition, a SON (Self-Organizing Network) system for eliminating the phenomenon of overlapping cells having the same PCI and automatically allocating the PCI of the cell has been developed and is in operation. The following patent document discloses an apparatus and method for allocating physical layer identification information of a home base station.

However, as described above, the conventional PCI allocation technique has proposed a technique for preventing cells having the same PCI from being overlapped. However, studies on improving the quality of the communication service through PCI allocation have been limited.

Korean Patent Publication No. 10-2011-0018043

It is an object of the present invention to provide a cell management method and apparatus for improving the quality of a communication service through PCI re-establishment.

Other objects and advantages of the present invention will become apparent from the following description, and it will be understood by those skilled in the art that the present invention is not limited thereto. It will also be readily apparent that the objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

According to a first aspect of the present invention, there is provided a method of managing a cell for improving communication quality in a communication system, comprising: collecting data generated in each cell; Extracting the serving cell related data from the collected data; Analyzing the extracted serving cell related data to calculate at least one of an average collision rate of the serving cell and a collision rate of each target cell having the same reference value as the serving cell; If the collision rate of the calculated serving cell exceeds a threshold value or if at least one of the calculated collision rates of the target cell exceeds a threshold value, any one of a reference value different from the reference value of the serving cell is referred to as a change target reference ; Selecting one of PCI (Physical Cell Identity) generating the change target value as a change target PCI; And resetting the PCI of the serving cell based on the selected PCI.

According to a second aspect of the present invention, there is provided an operation management apparatus comprising: a storage unit for storing data generated in each cell; A cell collating unit for extracting serving cell related data from the storage unit and analyzing the extracted serving cell related data to calculate at least one of collision rate of each target cell having an average collision rate of the serving cell and a reference value same as the serving cell, Rate calculating unit; And if the collision rate of the calculated serving cell exceeds a threshold value or if at least one of collision rates of the calculated target cells exceeds a threshold value, any one of a reference value different from the reference value of the serving cell, And a PCI re-establishment unit for re-setting the PCI of the serving cell on the basis of the PCI determined as a change target PCI by selecting one of the reference values and the PCI (Physical Cell Identity) that generates the change target value .

The present invention is advantageous in that the PCI of the serving cell is reset so as to minimize the radio wave interference between the serving cell and the target cell, thereby improving the signal-to-noise ratio in the region where the cell is distributed.

In the present invention, when resetting the PCI of the serving cell, the PCI which is farthest from the serving cell among the PCIs causing the collision rate to be low is selected as the PCI of the serving cell, so that the PCI collision between neighboring cells is blocked .

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments of the invention and, together with the description, serve to explain the principles of the invention. And shall not be construed as limited to such matters.
1 is a diagram illustrating a mobile communication system according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating a configuration of an operation management server according to an embodiment of the present invention. Referring to FIG.
3 is a flowchart illustrating a method of reallocating a serving cell PCI in an operation management server according to an embodiment of the present invention.
FIGS. 4A and 4B are views illustrating statistical data on a collision rate between a serving cell and each target cell, according to an embodiment of the present invention.

The foregoing and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings, in which: There will be. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram illustrating a mobile communication system according to an embodiment of the present invention.

As shown in FIG. 1, a mobile communication system according to an embodiment of the present invention includes a plurality of base stations 100 and an operation management server 200.

The base station 100 is an eNB (Evolved NodeB), a femto base station, or the like, and forms a cell of an LTE communication network. The base station 100 performs initial connection and inter-sector handover of the mobile communication terminal, receives the radio signal from the mobile communication terminal, and transmits the received radio signal to the MME (Mobile Mobility Entity) (not shown) And transmits the wireless signal to the mobile communication terminal. In addition, the base station 100 can reset the PCI (Physical Cell Identity) of the currently set cell to another PCI according to an instruction from the operation management server 200.

In particular, the base station 100 transmits the handover data generated with the neighboring base station to the operation management server 200. At this time, the base station 100 transmits the serving cell PCI, the serving cell identification information, the reference value of the serving cell, the PCI of the target cell, the identification information of the target cell, And transmits the included handover data to the operation management server 200.

Here, the PCI (Physical Cell Identity) is one of the initial configuration parameters of a cell. It is a cell ID used in a physical layer to distinguish cells, and the number is limited to 504. The PCI is a specific number from '0' to '503', and is identification information that is allowed to be reused due to the number limitation.

The cell identification information is a unique ID given to the cell itself, and is information given by a company or a manufacturer. That is, the cell identification information is prohibited from being reused in general, unlike PCI.

The reference value is a remainder value obtained by dividing PCI by a specific divisor, and is a reference data for frequency shift in a cell. For example, when the PCI is '4' and the divisor is '3', the reference value becomes '1'. The divisor is a specific constant (e.g., 3), which is kept the same in the mobile communication system and typically the number '3' is used. The reference value is changed based on the PCI of the cell. On the other hand, when the reference value is the same between neighboring cells, a signal-to-noise ratio is lowered due to frequency interference, and handover frequently occurs.

The operation management server 200 is an apparatus for monitoring and managing operations of each base station 100. The operation management server 200 stores handover data received from each base station 100 and analyzes the stored data to determine a collision rate If there is a cell exceeding the threshold value, the PCI for this cell is reallocated.

FIG. 2 is a diagram illustrating a configuration of an operation management server according to an embodiment of the present invention. Referring to FIG.

2, the operation management server 200 according to the preferred embodiment of the present invention includes a data collecting unit 210, a storage unit 220, a conflict rate calculating unit 230, and a PCI resetting unit 240, .

The data collecting unit 210 collects data generated in each base station 100, in particular, handover data, and stores the data in the storage unit 220.

The storage unit 220 stores a plurality of handover data. The handover data includes serving cell identification information, a serving cell PCI, a target cell identification information, a target cell PCI, a serving cell reference value, and a target cell reference value. In addition, the storage unit 220 stores cell installation information including location information of each cell, PCI, and cell identification information.

The collision rate calculator 230 analyzes the data stored in the storage unit 220 and calculates the average collision rate of the serving cell and the collision rate of each target cell. Specifically, the collision rate calculator 230 selects a specific serving cell, extracts the handover data in which the identification information of the serving cell is stored from the storage unit 220, analyzes the extracted handover data, The average collision rate between each serving cell and the serving cell is calculated, and the collision rate between the serving cell and the target cell is calculated for each target cell. The collision rate calculator may analyze the handover data to calculate an average collision rate between the serving cell and the target cell having a reference value different from the reference value of the serving cell.

The PCI resetting unit 240 performs a function of resetting the PCI of the serving cell based on the collision rate calculated by the collision rate calculating unit 230. [ That is, when the average collision rate of the serving cell or the collision rate between the serving cell and the specific target cell calculated by the collision rate calculator 230 exceeds the threshold, the PCI resumption unit 240 resets the PCI of the serving cell to another PCI Proceed with the resetting procedure. Specifically, the PCI resumption unit 240 checks a reference value having the lowest collision rate among the average collision rates calculated by the collision rate calculation unit 230, and sets the reference value as a reference value of the serving cell . The PCI resetter 240 resets the PCI of the cell located within a certain radius of the serving cell and capable of generating the selected reference value from the storage unit 220 based on the cell installation information stored in the storage unit 220 And records the PCIs of the extracted cells in the candidate target PCI list. Preferably, the PCI resetter 240 identifies the PCI of each target cell that handed over the serving cell from the handover data, and removes the identified PCI from the candidate target PCI list. In addition, the PCI resuming unit 240 may check the PCI which is given by the cell farthest from the serving cell in the candidate target PCI list, recommend the recommended PCI to the administrator and recommend to the administrator, And resets the PCI of the serving cell to be the PCI of the serving cell.

3 is a flowchart illustrating a method of reallocating a serving cell PCI in an operation management server according to an embodiment of the present invention.

Referring to FIG. 3, the data collecting unit 210 collects handover data from each base station 100 and stores the data in the storage unit 220 (S301). The handover data includes the PCI of the serving cell, the PCI of the target cell, the target cell identification information, the serving cell identification information, the reference value of the serving cell, and the reference value of the target cell.

In the state where the handover data of each base station 100 is stored in the storage unit 220, the collision rate calculator 230 selects a cell to be analyzed, and the identification information of the selected cell is used as the identification information of the serving cell The stored plurality of handover data is extracted from the storage unit 220 (S303). At this time, the collision rate calculator 230 may receive the cell to be analyzed from the manager, and may also select a specific cell arbitrarily, or may select a cell distributed in an area where reception quality of the call quality is high, have. Preferably, the collision rate calculator 230 extracts, from the storage unit 220, the handover data of the serving cell that occurred during a predetermined period (e.g., a day or a week). Then, the collision rate calculator 230 counts the total number of extracted handover data and confirms the total number of handovers performed in the serving cell (S305).

Next, the collision rate calculator 230 extracts handover data for the target cell having the same reference value as the serving cell among the plurality of extracted handover data as collision rate analysis subject data (S307). That is, the collision rate calculator 230 calculates a plurality of handover data in which the same reference value as the serving cell is recorded as the reference value of the target cell among the plurality of handover data generated as the handover with the serving cell progresses And extracts it as collision analysis target data.

Next, the collision rate calculator 230 counts the number of handover data extracted as the collision-analysis target data, and confirms the counted handover data as the number of handover times of the serving cell in which the reference value is collided (S309). Then, the collision rate calculator 230 substitutes the total number of handovers of the serving cell in which the total number of handovers of the serving cell and the reference value of the serving cell are collided, into the following equation (1) The average collision rate is calculated (S311). That is, since the reference values are the same, the collision rate calculator 230 calculates the average collision rate occurring between the serving cell and the target cell through the following equation (1).

a: Number of handover of the serving cell in which the reference value is collided

b: total number of handover handles of the serving cell

Then, the collision rate calculator 230 counts the number of handovers of each target cell by counting handover data having the same target cell identification information among the handover data extracted as collision-analysis target data for each target cell (S313 ).

Then, the collision rate calculator 230 calculates the collision rate between the serving cell and the target cell based on the total number of handover of the serving cell and the number of handover of the target cell (S315). At this time, the collision rate calculator 230 calculates the collision rate between the serving cell and the target cell by substituting the total number of handovers of the serving cell and the number of handovers of the target cell in Equation (2).

c: Number of handovers between a serving cell and a specific target cell

d: total number of handover handles of the serving cell

FIGS. 4A and 4B are views illustrating statistical data on a collision rate between a serving cell and each target cell, according to an embodiment of the present invention.

Referring to FIGS. 4A and 4B, for example, steps S303 to S315 will be described. The collision rate calculator 230 selects a cell having identification information '3882999' as a serving cell to be analyzed. A plurality of handover data in which the identification information of '3882999' is recorded as the identification information of the serving cell is extracted from the storage unit 220. The collision rate calculator 230 checks the total number of extracted handover data and confirms the total number of handovers performed in the serving cell. 4A shows the statistical data of the serving cell. In FIG. 4A, the collision rate calculator 230 calculates the total number of handover handover times of the serving cell according to the number of extracted handover data '80860' Is " 80860 ".

The collision rate calculator 230 calculates the collision rate of the target cell with the same value as the reference value of the serving cell (i.e., '1') among the extracted plurality of handover data (i.e., among 80860 handover data) Is extracted as the analysis target data. Next, the collision rate calculator 230 counts the number of handover data extracted as the analysis target data, and confirms that the counted handover data is the number of handover times of the serving cell in which the reference value is collided. In FIG. 4A, it is illustrated that the number of handovers in which the reference value is collided with the serving cell is '47613'.

The collision rate calculator 230 substitutes the number of handovers 47613 and the total number of handovers 80860 of the serving cell in which the reference value (i.e., 1) collides with the serving cell into Equation (1) (I.e., 58.88%) between the serving cell and the target cell, which is '1'.

Then, the collision rate calculator 230 counts the handover data having the same target cell identification information among the handover data selected as the analysis target data for each target cell, and confirms the number of handovers of each target cell. 4, the target cell having identification information of '38801111' in FIG. 4 is a target cell having a serving cell and a target having a handover count '34743' and having identification information of '38801112' Cell is handed over to the serving cell '5931' times.

The collision rate calculator 230 calculates the collision rate between each target cell and the serving cell by substituting the number of handover times of the target cell and the total number of serving cell handover into Equation (2). The collision rate of the target cell having the identification information of '38801111' is 42.97% because the number of handover of the target cell having the identification information of '38801111' is '34743' and the total number of the serving cell handovers is '80860' .

When the collision rate between the serving cell and the target cell is calculated by the collision rate calculation unit 230, the PCI resumption unit 240 determines whether the average collision rate of the serving cells exceeds a threshold (for example, 50%), It is checked whether there is a target cell having a collision rate exceeding a value (e.g., 50%) (S317).

If there is no target cell having a collision rate exceeding the threshold value among the target cells without the average collision rate of the serving cells not exceeding the threshold value, the PCI resumption unit 240 resets the serving cell and the serving cell It is determined that radio interference frequently occurs due to the reference value between neighboring cells (i.e., target cells), and the PCI of the serving cell is maintained as it is.

On the other hand, if there is a target cell having a collision factor at which the average collision rate of the serving cell exceeds a threshold value or exceeds the threshold value among the target cells, the PCI re- It is judged that radio wave interference occurs frequently. In order to change the reference value of the serving cell, the PCI resetsection 240 instructs the collision rate calculator 230 to calculate the average collision rate between the serving cell and the target cell having a reference value different from the reference value of the serving cell .

Then, the collision rate calculator 230 re-selects the handover data excluding the analysis target data from among the handover data extracted in step S303 (i.e., the handover data in which the identification information of the selected serving cell is recorded) And groups the handover data having the same reference value among the re-selected handover data. The collision rate calculator 230 divides grouped handover data into groups and counts them, and checks the total number of handovers of groups having the same reference value for each group. For example, when the handover data having the reference value '0' is '2812', it is confirmed that the number of handover of the group having the reference value '0' is '2812'.

Then, the collision rate calculator 230 calculates the average collision rates of the serving cells and the target cells having the same reference value, based on the number of handovers of the group and the total number of handover of the serving cell confirmed in step S305 (S319). That is, the collision rate calculator 230 divides the total number of handovers of the serving cell by the number of handovers of the group having the same reference value, so that the average collision rate between the serving cell and the target cell that is not the same as the reference value of the serving cell Is calculated for each reference value. For example, when the number of handovers of a group having a reference value of '0' is' 2812 'and the total number of handovers of a serving cell is' 80860', the collision rate calculator 230 determines that the serving cell and the reference value are ' The average collision rate of handover between the target cells is calculated to be 3.47%.

When the average collision rate between the serving cell and the serving cell is calculated by the collision rate calculator 230, the PCI resetter 240 calculates the average collision rate of the target cell The reference value is confirmed, and this reference value is selected as a reference value of the serving cell to be changed (S321).

Then, the PCI resumption unit 240 resets the cell 220 of the cell 220, which is located within a certain radius of the serving cell and has the PCI that can generate the selected reference value, based on the cell installation information stored in the storage unit 220 And generates a candidate target PCI list in which the PCIs of the plurality of cells confirmed are recorded (S323). Preferably, the PCI resetter 240 identifies the PCI of each target cell handed over from the serving cell, from the handover data, and removes the identified PCI from the candidate target PCI list.

Then, the PCI resuming unit 240 confirms the PCI allocated to the cell farthest from the serving cell among the candidate target PCI list, and recommends the confirmed PCI to the administrator and recommends the PCI to the administrator (S325, S327) .

Next, when the PCI reset unit 240 receives an input signal to change the PCI of the serving cell to the recommended PCI from the manager, it transmits a PCI change command message to the base station 100 forming the serving cell, To the recommended PCI. Meanwhile, the PCI resuming unit 240 may change the PCI of the serving cell by transmitting a PCI change message to the base station 100 to immediately change to the recommended PCI without receiving an input signal from the manager.

Meanwhile, the procedure of FIG. 3 described above is for one cycle, and the operation management server 200 may select another serving cell and proceed to the process after step S303.

As described above, the operation management server 200 according to the present invention resets the PCI of the serving cell to minimize the collision of the reference value caused by the radio wave interference between the serving cell and the target cell, Improve the noise ratio, and ultimately improve the quality of the communication service. In addition, when resetting the PCI of the serving cell, the operation management server 200 according to the present invention selects a PCI that is farthest from the serving cell among the PCIs causing a low collision rate to be the PCI of the serving cell, It essentially blocks PCI conflicts that occur.

While the specification contains many features, such features should not be construed as limiting the scope of the invention or the scope of the claims. In addition, the features described in the individual embodiments herein may be combined and implemented in a single embodiment. Conversely, various features described in the singular < Desc / Clms Page number 5 > embodiments herein may be implemented in various embodiments individually or in combination as appropriate.

Although the operations have been described in a particular order in the figures, it should be understood that such operations are performed in a particular order as shown, or that all described operations are performed to obtain a sequence of sequential orders, or a desired result . In certain circumstances, multitasking and parallel processing may be advantageous. It should also be understood that the division of various system components in the above embodiments does not require such distinction in all embodiments. The above-described program components and systems can generally be implemented as a single software product or as a package in multiple software products.

The method of the present invention as described above can be implemented by a program and stored in a computer-readable recording medium (CD-ROM, RAM, ROM, floppy disk, hard disk, magneto optical disk, etc.). Such a process can be easily carried out by those skilled in the art and will not be described in detail.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. The present invention is not limited to the drawings.

100: Base station 200: Operation management server
210: data collecting unit 220; The storage unit
230: collision rate calculating unit 240: PCI re-

Claims (14)

A method of managing a cell to improve communication quality in a communication system,
Collecting data generated in each cell;
Extracting the serving cell related data from the collected data;
Analyzing the extracted serving cell related data to calculate at least one of an average collision rate of the serving cell and a collision rate of each target cell having the same reference value as the serving cell;
If the collision rate of the calculated serving cell exceeds a threshold value or if at least one of the calculated collision rates of the target cell exceeds a threshold value, any one of a reference value different from the reference value of the serving cell is referred to as a change target reference ;
Selecting one of PCI (Physical Cell Identity) generating the change target value as a change target PCI; And
And resetting the PCI of the serving cell based on the selected PCI. The method according to claim 1,
Wherein the step of selecting the change target PCI comprises:
Identifying neighboring cells located within a certain radius of the serving cell;
Selecting a cell to which the PCI is allocated to generate the change target reference value among the identified peripheral cells; And
Identifying a cell farthest from the serving cell among the selected cells and selecting a PCI to be allocated to the cell as the change target PCI. 3. The method of claim 2,
The step of selecting,
Wherein cells are selected by excluding the serving cell and the target cell from which the handover has been performed. 4. The method according to any one of claims 1 to 3,
Wherein the calculating step comprises:
Analyzing the extracted data to check the total number of handovers of the serving cell;
Extracting data for one or more target cells having the same reference value as the serving cell from the extracted data and analyzing data of the extracted one or more target cells to check the total number of handovers of the target cell; And
And calculating an average collision rate of the serving cell by dividing the total number of handovers of the serving cell by the total number of handovers of the target cell. 4. The method according to any one of claims 1 to 3,
Wherein the calculating step comprises:
Analyzing the extracted data to check the total number of handovers of the serving cell;
Extracting data on one or more target cells having the same reference value as the serving cell from the extracted data, analyzing the extracted data, and checking the number of handovers per target cell; And
And calculating a collision rate of each target cell by dividing the total number of handovers of the serving cell by the number of handovers of the target cell. 4. The method according to any one of claims 1 to 3,
Wherein the step of selecting the change target value comprises:
Confirming, in the extracted data, data of a target cell having a reference value different from a reference value of the serving cell;
Analyzing data of the identified target cell and calculating an average collision rate between the target cell having the different reference value and the serving cell according to the reference value; And
And selecting the reference value having the lowest average collision rate as the change target value. 4. The method according to any one of claims 1 to 3,
The step of resetting the PCI of the serving cell comprises:
And recommends the selected PCI to the manager as the reset PCI of the serving cell and resets the PCI of the serving cell based on the selected PCI when receiving the reset input from the manager. A storage unit for storing data generated in each cell;
A cell collating unit for extracting serving cell related data from the storage unit and analyzing the extracted serving cell related data to calculate at least one of collision rate of each target cell having an average collision rate of the serving cell and a reference value same as the serving cell, Rate calculating unit; And
If the collision rate of the calculated serving cell exceeds a threshold value or if at least one of the calculated collision rates of the target cell exceeds a threshold value, any one of a reference value different from the reference value of the serving cell is referred to as a change target reference And a PCI re-establishment unit for re-setting the PCI of the serving cell based on the determined PCI by determining any one of PCIs (Physical Cell Identity) generating the reference value to be changed as a change target PCI, Operational management device. 9. The method of claim 8,
The PCI re-
A cell allocated to a PCI that can generate the reference value to be changed among peripheral cells located within a certain radius of the serving cell is selected and a PCI allocated to a cell farthest from the serving cell among the selected cells is changed And a target PCI is selected. 10. The method of claim 9,
The PCI re-
And selects a cell excluding the serving cell and the target cell in which the handover has been performed. 11. The method according to any one of claims 8 to 10,
Wherein the collision rate calculator calculates,
Analyzing the extracted serving cell related data to check the total number of handovers of the target cell having the same total number of handovers of the serving cell and the same reference value as the serving cell, Wherein the average collision rate of the serving cell is calculated by dividing the total number of handovers of the serving cell. 11. The method according to any one of claims 8 to 10,
Wherein the collision rate calculator calculates,
The mobile station analyzes the extracted serving cell related data to check the total number of handovers of the serving cell and the number of handovers per target cell having the same reference value as the serving cell, And calculates the collision rate of each target cell by dividing the total number of times. 11. The method according to any one of claims 8 to 10,
The PCI re-
The data of the target cell having the reference value different from the reference value of the serving cell is selected from the extracted serving cell related data, the data of the selected target cell is analyzed, and the target cell having the different reference value and the serving cell And selects a reference value having the lowest average collision rate as the change target value. 11. The method according to any one of claims 8 to 10,
The PCI re-
And recommends the selected PCI to the administrator as a reset PCI of the serving cell and resets the PCI of the serving cell based on the selected PCI when receiving the reset input from the manager.

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