KR102398168B1 - method for estimating position of base station of mobile telecommunication system - Google Patents

Abstract

The present invention relates to a method for estimating the location of a base station in a mobile communication system, which estimates the location of a base station by using quality data of a mobile communication network collected during a drive test to minimize a process of verifying actualization of the base station by engineers. According to the present invention, the method is performed on log data collected periodically, which includes quality data of a mobile communication network, during a drive test performed while moving a vehicle having a mobile communication terminal mounted thereon. The method comprises the following steps of: (a) grouping the log data on the basis of the same physical-layer cell ID (PCI) and eNB ID to extract a plurality of road sections from a road on which the vehicle traveled; (b) dividing each road section extracted in the step (a) into straight roads in which the quality data simply increases or decreases; (c) when the quality data increases with respect to each straight road generated in the step (b), setting the end point of the straight road as a reference point, whereas when the quality data decreases, the starting point of the straight road is set as the reference point; (d) setting a radius area centered on the reference point set in the step (c) as an expected location range of the base station; and (e) estimating an area where the expected range set in the step (d) overlaps as the location of the base station.

Description

Method for estimating position of base station of mobile telecommunication system

The present invention relates to a method for estimating the location of a base station in a mobile communication system, and in particular, by estimating the location of a base station using quality data of a mobile communication network collected during a drive test, a mobile communication method that minimizes an engineer's process of verifying the current base station It relates to a method for estimating a base station position in a system.

As is well known, by collecting and analyzing the radio wave environment in the mobile communication system, it finds radio wave defects and shaded areas, analyzes the cause and shows it so that it can be identified with the naked eye, and compares the design goal with the actual quality after network construction. For the purpose of generating basic data such as base station extension or relocation, a mobile communication terminal manufacturer, a mobile communication operator, or a mobile communication network optimization solution provider is conducting a drive test.

This drive test occurs in the process of connecting to a predetermined site according to a predetermined scenario and downloading data or connecting to a predetermined mobile communication terminal and exchanging voice or text messages while driving on a road with one or more mobile communication terminals installed in the vehicle. After collecting various log data periodically, for example, in units of 1 second, on a tablet PC or notebook PC connected to a mobile communication terminal through a DM (Diagnostic Monitoring) port, it undergoes a post-analysis process.

On the other hand, for base station optimization, it is very important to know exactly where the base station is installed. Since the location of the base station is a confidential matter of each mobile operator, a mobile communication terminal manufacturer, another mobile operator, or a base station optimization solution provider There was a problem in that it was difficult to measure wireless quality or to work on an optimization solution, and to create business opportunities through this, if the location of the base station or information on the affiliated mobile communication service provider could be known.

In view of this, conventionally, while performing a drive test, an experienced engineer in a vehicle estimates the location of the base station while checking the log data collected in real time. Depending on the degree, there has always been a possibility that a human error may occur in the location estimation result.

Prior Art 1: 10-2005-0044016 Laid-Open Patent Publication (Title of the Invention: Repeater Location Searching Apparatus and Method)

Prior Art 2: Patent Publication No. 10-0456306 (Title of Invention: Base Station Positioning System)

Prior Art 3: 10-1893053 Registered Patent Publication (Title of Invention: Automatic detection method of small cell installation location change)

The present invention has been devised to solve the above problems, and it is a mobile communication system that minimizes an engineer's process of verifying the current base station by estimating the location of the base station by utilizing the quality data of the mobile communication network collected during the drive test. An object of the present invention is to provide a method for estimating a position of a base station.

In the method for estimating the location of a base station of a mobile communication system of the present invention for achieving the above object, log data periodically collected including quality data of a mobile communication network while performing a drive test while moving while a mobile communication terminal is mounted in a vehicle (a) grouping log data based on the same PCI and eNB ID and extracting a plurality of road sections from the road on which the vehicle travels; (b) dividing each road section extracted in step (a) into a straight road in which the quality data simply increases or decreases; For each straight road created in step (b), when the quality data increases, the end point of the straight road is set as a reference point, whereas when the quality data decreases, the starting point of the straight road is set as the reference point (c) setting; Step (d) of setting the radius area centered on the reference point set in step (c) as the expected range of the base station and (e) estimating the area where the expected range set in step (d) overlaps as the location of the base station is made including

In the above configuration, the quality data is RSRP (Reference Signal Received Power) received by the mobile communication terminal from the base station.

Convert the collected log data into a csv file in the form of a log table consisting of rows and columns, wherein the row (horizontal) of the log table is the log data collection time of the drive test, and the column (vertical) of the log table is the log data GPS coordinates of the collected points, vehicle travel speed and the eNB ID, serving PCI and serving RSRP information.

Information on the moving angle of the vehicle calculated through the GPS coordinates is added to the log table.

(pa) of performing pre-processing of deleting empty rows in the log table before step (a), rows where the vehicle speed is 0 km, and rows in which the GPS coordinates do not change compared to the previous row be prepared

After step (a) and before step (b), when each road section extracted in step (a) satisfies a condition to be divided into two roads, the step (a1) of dividing into two roads is further provided do.

The road segmentation condition is determined that each road section extracted in step (a) is bent by a reference angle or more.

The road segmentation condition is determined that the time interval between the log data collection points for each road section extracted in step (a) is equal to or greater than a reference value.

After the step (a) and before the step (b), when the two road sections extracted in step (a) satisfy the condition to be merged, the step (a2) of merging into one road is further provided. .

The road section in which the RSRP neither increases nor decreases after step (a) is excluded from the base station location estimation process.

The road section in which the RSRP increases and then decreases after step (a) is divided into two roads based on the maximum point of the RSRP.

The radius area is set differently according to regional characteristics.

According to the method for estimating the location of the base station of the mobile communication system of the present invention, the work time and human error required for verifying the current base station without an engineer's on-site inspection by estimating the location of the base station using the quality data of the mobile communication network collected during the drive test can be minimized.

1A and 1B are diagrams for explaining the principle of a method for estimating a base station position in a mobile communication system of the present invention;
2 is a flowchart for explaining a method for estimating a base station position in a mobile communication system of the present invention.
3 is a diagram for explaining a process of dividing one road into two roads in the method for estimating the location of a base station in a mobile communication system of the present invention;
4 is a diagram for explaining a process of merging two or more roads into one road in the method for estimating the location of a base station in a mobile communication system of the present invention;
5 is a diagram for explaining a process of dividing two or more roads based on the maximum point of the RSRP on the road where the RSRP increases and then decreases in the method for estimating the location of the base station of the mobile communication system of the present invention.
6A and 6B are diagrams for explaining a process of setting an expected base station location range in a method for estimating a base station location in a mobile communication system of the present invention, respectively;
7 is a diagram for explaining the final estimation process of the base station position in the method for estimating the position of the base station of the mobile communication system of the present invention.

Hereinafter, a preferred embodiment of a method for estimating a base station position in a mobile communication system of the present invention will be described in detail with reference to the accompanying drawings.

The basic principle of the method for estimating the position of the base station of the mobile communication system of the present invention is the quality data of the mobile communication network, specifically, the strength of the signal received by the mobile communication terminal from the base station, for example, RSRP (Reference Signal Received Power) or RSSI (Received Signal). Strength Indicator) (hereinafter, 'RSRP' as an example will be used as an example) is inversely proportional to the distance between the mobile communication terminal and the base station. to estimate the location.

1A and 1B are diagrams for explaining the principle of a method for estimating a position of a base station in a mobile communication system of the present invention. When the base station is located at a specific point on the map illustrated in FIG. 1A, when the drive test vehicle moves along the arrow direction on road ①, it gets closer to the base station and the RSRP increases as time goes by as shown in the left graph of FIG. 1B something to do. In the graph of Figure 1b, the vertical axis represents RSRP, and the horizontal axis represents time.

Next, when the vehicle to be tested drives along the direction of the arrow ②, the RSRP will decrease as time goes by as the vehicle moves further away from the base station as shown in the middle graph of FIG. 1b. Finally, when the drive test vehicle moves along the direction of the arrow on road No. 3, it gets closer to the base station and the RSRP will increase as time goes by as shown in the graph on the right of FIG. 1b.

2 is a flowchart for explaining a method for estimating a base station location in a mobile communication system of the present invention, and may be performed through an analysis program on log data collected during a drive test.

First, in step S100, during a drive test while driving a vehicle, an analysis program mounted on a mobile communication terminal and, for example, a tablet PC or a notebook PC connected through a USB interface, is periodically logged from the mobile communication terminal at intervals of, for example, 1 second. Data is collected, and the log file thus collected is converted into a table in the form of a csv (Comma-Separated Variables) file through a converter to be used for estimating the location of the base station in the future. Here, the rows (horizontal) of the table of the csv file (hereinafter referred to as the 'log table') are sampled at the log data collection time of the drive test, for example, every 1 second, and the column (vertical) of the log table is the log data consists of the collected point's GPS coordinates, vehicle travel speed and various RF parameters, such as eNB (base station) ID, serving PCI (Physical-layer Cell ID), and serving RSRP information. The calculated vehicle movement angle information is added.

For reference, there are 504 PCIs defined in LTE, and these 504 PCIs are composed of a combination of 168 cell group (eNB) IDs (0 to 167) and 3 cell sector IDs (0 to 2), that is, PCI. = eNB ID (168) * Cell sector ID (3).

Next, in step S110, pre-processing is performed on the log data collected in this way. Specifically, an empty row or a row with a vehicle speed of 0 km in the log table is deleted because it corresponds to a case where the vehicle is stopped or a bug occurs. Similarly, the row in which the GPS coordinates of the vehicle do not change compared to the previous row are deleted by determining that the vehicle is in a stationary state.

In this way, after the pre-processing is completed, steps S120 to S160 are performed to extract a plurality of straight roads from the road the vehicle moved on during the drive test. For this, first, in step S120, each drive based on the same PCI and eNB ID A plurality of road sections are extracted by grouping test points.

Next, in S130, the condition for dividing each road section extracted through step S120 into two roads is satisfied, for example, one road section is a predetermined reference value, for example, a reference value determined within 20° to 45° In the case of an abnormal bend, the process proceeds to step S140 and the corresponding road is divided into two roads.

3 is a diagram for explaining a process of dividing one road into two roads in the method for estimating the location of a base station in a mobile communication system of the present invention, a green arrow solid line indicates a moving direction of the vehicle, and a blue dot is a log data collection point , and the number “461” indicates a serving PCI.

In the example of FIG. 3, as the vehicle turned right at the 4-way intersection during the drive test, the road trajectory on which the vehicle moved was bent more than the reference angle. In this case, as shown in the right drawing of FIG. Two roads are extracted by dividing the corresponding road section.

On the other hand, if the time difference between the log data collection points during the drive test process is large, it is highly likely that the vehicle stopped and started due to signal waiting, and accordingly, changes in the RF environment occurred between the time before and after, that is, during vehicle standby. Since the possibility is high, even if it is one road section, it is preferable to divide the corresponding road section into two roads based on the time difference.

In this way, when the road division operation is completed, step S150 is performed again to determine whether there is a road that needs to be merged among the two divided roads. If it is necessary to merge any two roads into one road in step S150, the process proceeds to step S160 and the two roads are merged into one road. For example, even though it is a straight road section due to a GPS location estimation error, etc., if the angle is temporarily bent and divided into two or more straight roads, or if the PCI is temporarily changed and divided into two or more straight roads, merging them into one road desirable.

4 is a diagram for explaining the process of merging two or more roads into one road in the method for estimating the location of a base station in a mobile communication system of the present invention, a green arrow solid line indicates the moving direction of the vehicle, and a red dot is log data collection points, and the numbers "440" and "408" represent the serving PCI, respectively.

In the example of FIG. 4, even though the vehicle traveled on a straight road section during the drive test, the road was bent beyond the reference angle due to a GPS location estimation error and divided into two or more roads. In this case, the road direction before and after the bend It is preferable to merge into one road as shown in the right drawing of FIG. 4 in consideration of the length of the parts, etc.

In the same way, as shown in FIG. 4, even if the PCI is temporarily changed in some road sections and divided into two roads, the length or direction of the road before and after the PCI change and the length of the section in which the PCI is changed are comprehensively considered. It is preferable to merge two roads into one road as shown in the right drawing of FIG. 4 .

On the other hand, in the process of extracting the straight road in this way, if the length of the straight road is too short or the number of log data collection points is less than the reference value, it is difficult to analyze the change in sufficient RSRP, so it is preferable to delete the straight road.

RSRPs collected from the road extracted through the above process simply increase over time (closer to the base station), simply decrease over time (away from the base station), as time goes by It can have four patterns: a case of increasing and then decreasing (passing through a base station) and a case of neither increasing nor decreasing.

Among the RSRP change patterns described above, it is preferable to delete a road having neither an increase nor a decrease in the pattern because it is not suitable for estimating the position of the base station by the change of the RSRP in the corresponding road section.

On the other hand, in the case of a road in which RSRP increases and then decreases as time passes, it is preferable to divide the road into two roads based on the maximum point of RSRP because it is not suitable for estimating the location of the base station as the length of the road increases.

5 is a diagram for explaining a process of dividing two or more roads based on the maximum point of the RSRP in the method for estimating the location of the base station of the mobile communication system of the present invention. Through this, a relatively long road is divided into a road in which the RSRP simply increases and a road in which the RSRP simply decreases as time goes by.

If, through this process, the road section driven by the vehicle during the drive test is divided into straight roads in the form of a simple increase or decrease in RSRP, step S170 is performed to group the straight roads divided by PCI based on the eNB ID.

Next, in step S180, a reference point and a reference line are selected for estimating the position of the base station. In the case of a straight road in which the RSRP simply increases, since the base station is located in front of the straight road, the end point of the straight road is the reference point. select Conversely, in the case of a straight road in which RSRP simply decreases, since the base station is located behind the straight road, the starting point of the straight road is selected as the reference point. Meanwhile, the reference line becomes a line passing through the reference point while forming a right angle with the corresponding straight road.

Next, in step S190, an expected range in which the base station is located is set based on each reference point selected in this way.

6A and 6B are diagrams for explaining a process of setting an expected base station position range in the method for estimating the position of the base station of the mobile communication system according to the present invention, respectively. First, as shown in Fig. 6a, when the expected range in which the base station is located is simply set through the reference line extracted in step S180, the area becomes infinitely large. It is preferable to reduce the expected range to within a predetermined radius of the center. In this case, the radius can be set relatively short, for example, about 1 to 2 km, in a downtown area where base stations are relatively dense, whereas in areas such as suburbs or plains, the radius can be set relatively wide, about 5 to 10 km. will be.

Returning to FIG. 2 again, in steps S200 and S210, an overlapping area among a plurality of estimated base station location ranges set in this way is estimated as the final base station location and the result is output.

7 is a diagram for explaining a final base station location estimation process in the base station location estimation method of the mobile communication system of the present invention. In FIG. 7 , the red arc portion of the central region of the map is finally estimated as the location where the base station is installed. Through this method, the location of the base station can be accurately estimated with little time and manpower.

Above, the preferred embodiment of the method for estimating the base station position of the mobile communication system of the present invention has been described in detail with reference to the accompanying drawings, but this is merely an example, and various modifications and changes may be made within the scope of the technical spirit of the present invention. . Accordingly, the scope of the present invention should be defined by the description of the following claims. For example, in order to more accurately estimate the location of the base station, steps S130 to S160 of FIG. 2 may be performed twice or more.

Claims (12)

While carrying out the drive test while moving with the mobile communication terminal mounted on the vehicle, it is performed on log data periodically collected including quality data of the mobile communication network and GPS coordinates,
(a) grouping log data based on the same PCI and eNB ID and extracting a plurality of road sections from the road on which the vehicle travels;
(b) dividing each road section extracted in step (a) into straight roads in which the quality data simply increases or decreases;
For each straight road created in step (b), when the quality data increases, the end point of the straight road is set as a reference point, whereas when the quality data decreases, the starting point of the straight road is set as the reference point (c) setting;
(d) setting the radius area centered on the reference point set in step (c) as the expected range of the base station location; and
The method for estimating the location of a base station in a mobile communication system, comprising the step of (e) estimating, as the location of the base station, the area where the expected range set in step (d) overlaps. The method according to claim 1,
Wherein the quality data is RSRP (Reference Signal Received Power) received by the mobile communication terminal from the base station. 3. The method according to claim 2,
Converts the collected log data into a csv file in the form of a log table consisting of rows and columns, wherein the row (horizontal) of the log table is the log data collection time of the drive test, and the column (vertical) of the log table is the log data The method for estimating the location of a base station in a mobile communication system, characterized in that the collected points are GPS coordinates, vehicle travel speed, and the eNB ID, serving PCI and serving RSRP information. 4. The method according to claim 3,
The method for estimating the position of a base station in a mobile communication system, characterized in that information on the vehicle's movement angle calculated through the GPS coordinates is added to the log table. 5. The method according to claim 4,
(pa) of performing pre-processing of deleting empty rows in the log table before step (a), rows where the vehicle speed is 0 km, and rows in which the GPS coordinates do not change compared to the previous row A method for estimating the location of a base station in a mobile communication system, characterized in that it is provided. 5. The method according to claim 4,
After step (a) and before step (b), when each road segment extracted in step (a) satisfies a condition to be divided into two roads, the step (a1) of dividing into two roads is further provided A method for estimating the position of a base station in a mobile communication system, characterized in that one. 7. The method of claim 6,
The road division condition is a method for estimating the location of a base station in a mobile communication system, characterized in that each road section extracted in step (a) is bent by a reference angle or more. 7. The method of claim 6,
In the road division condition, the time interval between the log data collection points for each road section extracted in step (a) is equal to or greater than a reference value. 5. The method according to claim 4,
After the step (a) and before the step (b), when the two road sections extracted in step (a) satisfy the condition to be merged, the step (a2) of merging into one road is further provided. A method for estimating the location of a base station in a mobile communication system, characterized in that. 5. The method according to claim 4,
The method of estimating the position of a base station in a mobile communication system, characterized in that the road section in which the RSRP neither increases nor decreases after step (a) is excluded from the process of estimating the position of the base station. 5. The method according to claim 4,
The method for estimating the position of a base station in a mobile communication system, characterized in that the road section in which the RSRP increases and then decreases after step (a) is divided into two roads based on the maximum point of the RSRP. 12. The method according to any one of claims 1 to 11,
The method for estimating the location of a base station in a mobile communication system, wherein the radius area is set differently according to regional characteristics.

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