KR19990035739A - Cell Coverage Estimation in Wireless Network Design System - Google Patents

Abstract

1. Technical field to which the invention described in the claims belongs

The present invention relates to a cell coverage estimation method in a wireless network design system.

2. Technical Challenges to be Solved by the Invention

In order to improve the calculation speed of a radio wave analysis function implemented in a radio network design system, the present invention estimates cell coverage beforehand by using LOS (Line Of Sight), or estimates cell coverage in all bins corresponding to each radial A cell coverage estimation method that roughly estimates the cell coverage by calculating the received signal power only for the minimum number of bins necessary for the cell coverage calculation using an arbitrary search technique such as a half search technique instead of calculating the received signal power The purpose is to provide.

3. The point of the solution of the invention

The present invention includes a first step of searching for a line of sight (LOS) path for all radials by reading information about the terrain; A second step of finding a service area by connecting all the LOS points searched; And a third step of outputting the obtained service area, so that the service range can be estimated in a shorter time when the base station is located.

4. Important Uses of the Invention

The present invention is used in a wireless network design system.

Description

Cell Coverage Estimation in Wireless Network Design System

The present invention relates to a cell coverage estimation method for improving a calculation speed of a radio wave analysis function implemented in a radio network design system.

First, when defining terms used in the present invention, LOS (Line Of Sight) refers to a situation where there are no obstacles on the straight path of propagation in the propagation analysis.

Geographical Information System (GIS) is a collective term for facilities management (FM) and systems for handling vast amounts of land and terrain information for efficient management of geographical information. Most of them are handled in digital form because they are designed and managed using computers.

The GIS for the design of the wireless network should include information about the terrain and the property, especially the information such as the location, altitude, direction and material of the building, and the morphology of the terrain.

Digital Terrain Model (DTM) is a digital terrain model that digitizes a profile of a terrain. It is a terrain data model that stores altitude values and attribute information for each grid scale after creating a grid of appropriate intervals according to the application.

Cell coverage refers to a region where a wireless base station provides services. When using an omnidirectional antenna, the cell coverage can be shown as a circle having a radius d around the base station as shown in Fig. However, the shape of the actual cell coverage has an irregular shape due to the characteristics of the terrain and the building. The radio signal transmitted from the base station becomes weaker as it is farther from the base station. Then, when the signal power falls below a certain level, the call becomes impossible, and this point becomes the cell coverage boundary.

2 is a diagram illustrating an example of a cell map of an entire area for providing a wireless communication service (personal communication service, mobile communication service, city-2 service, etc.) based on analysis of cell coverage for each base station, So that any point in the service area can receive service from one or more base stations. At this time, as the number of base stations required to cover the service area is reduced as much as possible, the investment cost is reduced. On the other hand, if the distance between the base stations is too far, a shadow area of the radio wave occurs and the communication becomes impossible. Therefore, it is necessary to determine the position of the optimal base station through accurate analysis of the cell coverage covered by one base station. In general, cell coverage analysis of a base station will use a wireless network design system. The wireless network design system uses the GIS data to predict the received field strength at each point in the base station.

Most of the wireless network design systems that are currently commercialized for wireless communication providers provide basic functions for radio wave analysis, but most of them have basic problems in the calculation of radio waves.

That is, a method of analyzing accurate cell coverage for each base station using a wireless network design system usually requires a very long time. Therefore, unnecessary time and functions are wasted when it is necessary to determine the approximate cell site location. Accordingly, a faster approximate cell coverage estimation method is required.

FIG. 3 is an explanatory diagram of a range of a general radio wave analysis and a bin, and is for explaining a conventional cell coverage estimation method.

In a cell coverage estimation method implemented in most wireless network design systems currently commercialized, a calculation radius (d _max ) region 31 determined as shown in FIG. 3 is divided into a small square region 32 called a bin . The bin (BIN) is a basic unit of the received power prediction, and the predicted value of the received power of the center point represents the bin area.

Therefore, the smaller the bin (BIN), the more accurate coverage can be obtained, but the calculation speed is slowed down. The size of this bin can be arbitrarily determined by the user to determine the accuracy and speed of the predicted value.

The calculation for each bin (BIN) first sets the radial (33) over 360 degrees all the way at an angle that is sufficiently close to pass all bins. Then, the received electric field strength is calculated for all bins over each radial. For example, the bin extending over radial 5 34 in FIG. 3 calculates the received field strength for all five bins from bin 1 to bin 5 (35). At this time, the received electric field intensity for each bin is obtained using GIS data and propagation models provided by the system.

By repeating this process for all radials, the received field strength (P _bin ) for all bins in the calculation radius (d _max ) is obtained. And, the terminals of all wireless communication systems have the minimum receivable power (P _min ) that can be talked. The minimum received power (P _min ) is compared with the received field strength calculated value for each bin, and empty areas having a value larger than P _min form cell coverage.

In the conventional cell coverage estimation method as described above, unnecessary calculation is performed on all BINs within a calculation radius d _max because accurate cell coverage is sought. Even when only calculation of approximate cell coverage is required It requires a lot of execution time. On the other hand, in order to speed up the execution speed, it is necessary to increase the size of the bin, but in this case, the accuracy is deteriorated. Therefore, the conventional cell coverage estimation method is very unsuitable for use when it is necessary to calculate approximate cell coverage.

4 is a specific example of a conventional electromagnetic wave analysis method.

As shown in FIG. 4, the conventional radio wave analysis method reads the GIS data (DTM, vector) first (41), calculates a reception signal for each bin in the predetermined area as shown in FIG. 3 42), and the service area is appropriately displayed on the screen (43).

In designing a wireless network using the above-described conventional radio wave analysis method, it takes a lot of time to design a wireless network, and there is a problem in that it is difficult to perform post-management such as rearrangement.

In order to solve the above problems, it is an object of the present invention to provide a method and apparatus for estimating cell coverage in advance by using a LOS (Line Of Sight) And to provide a method for estimating coverage.

Another object of the present invention is to improve the calculation speed of the radio wave analysis function implemented in the radio network design system by not performing calculation of the received signal power for all bins corresponding to each radial, The present invention also provides a method of estimating cell coverage by estimating cell coverage in advance by calculating a received signal power only for a minimum number of bins necessary for cell coverage calculation using an arbitrary search technique such as

1 is an explanatory diagram of a general cell coverage radius;

2 is an explanatory diagram of a general wireless network design.

Fig. 3 is an explanatory diagram of a range of general radio wave analysis and bin.

4 is a specific example of a conventional radio wave analysis method.

5 is a block diagram of an embodiment of a wireless network design system to which the present invention is applied.

FIG. 6 is an explanatory diagram of a method for finding an LOS on each radial line according to an embodiment of the present invention; FIG.

FIG. 7 is an explanatory diagram of a cell coverage estimation method according to an embodiment of the present invention; FIG.

FIG. 8 is an explanatory diagram of a cell coverage estimation method according to another embodiment of the present invention; FIG.

FIG. 9 is an explanatory diagram of a cell coverage estimation method according to another embodiment of the present invention; FIG.

10 is a detailed flow diagram of a process 92 for searching for cell coverage beans in accordance with another embodiment of the present invention.

DESCRIPTION OF THE REFERENCE NUMERALS

51: computer 52: input device

53: Output device

According to an aspect of the present invention, there is provided a method of estimating cell coverage applied to a wireless network design system, the method comprising: a first step of searching for a LOS (Line Of Sight) path for all radials by reading information about a terrain; A second step of finding a cell coverage area by connecting all the LOS points searched; And a third step of outputting the obtained cell coverage area.

According to another aspect of the present invention, there is provided a method of estimating cell coverage applied to a radio network design system, comprising: setting parameters necessary for estimating cell coverage using a search technique; A first step of searching for a cell coverage bean; A second step of obtaining a cell coverage area by connecting all the cell coverage bins searched; And a third step of outputting the obtained cell coverage area.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

5 is a block diagram of an embodiment of a wireless network design system to which the present invention is applied.

The wireless network design system includes a basic computer 51 on which the present invention is implemented, an input device 52 for inputting the position of the base station, and an output device 53 for displaying and outputting the final service area A printer and a plotter are provided.

The present invention is basically an algorithm to be implemented in a wireless network design system using a computer, and its driving method starts with the position of a mouse as a position of a base station. That is, when the mouse is positioned at an arbitrary point on the digital map, the position of the point corresponding to the LOS when looking radially from the point is found. This will be described in more detail with reference to FIG.

FIG. 6 is an explanatory diagram of a method of finding an LOS on each radial line according to an embodiment of the present invention.

As shown in FIG. 6, when trying to find the LOS for each radial in the clockwise direction around the base station S, discussing the LOS on the buildings on the same radial, The first building or base point that is greater than the base station height is the LOS path.

If the LOS is established, the bean is accepted as a service area, and the same operation is performed for the remaining radials. When the above process is performed for the entire radial, desired bins satisfying the LOS path can be finally obtained. At this time, the service area is the inner area made up of these bins.

7 is an explanatory diagram of a cell coverage estimation method according to an embodiment of the present invention.

First, the GIS data is read 71, the LOS path is searched for the first radial 72, and it is determined whether the LOS path search is completed for all the radials 73. If the LOS path search has not been completed for all the radials After searching the LOS path (74), setting the next radial (75), and repeating the process of searching the LOS path for the set radial (72).

When the LOS path search is completed for all the radials, that is, the LOS search is performed from the first radial to the last radial, all the LOS points are connected (76) and the desired cell coverage area is finally obtained (77) .

8 is an explanatory diagram of a cell coverage estimation method according to another embodiment of the present invention.

As shown in the figure, as the radio wave propagates in the base station, the received power decreases. Depending on the type of search technique, the selection point is wrong, but the base station selects a point between the calculation radius (d _max ). At this time, in the case of a bi-section search technique, a midpoint is selected. The received power value P _bin of the _bin (BIN) corresponding to the selected point 81 is calculated.

If the received power value P _bin of the point 81 is larger than the minimum receivable power P _{min that} can be communicated as shown in FIG. 8, a point 82 between the point 81 and the calculated radius d _max is obtained. Is selected using a search technique. At this time, in the case of a bi-section search technique, a midpoint between the point 81 and the calculation radius d _max is selected. And calculates the reception power value P _bin of the _bin (BIN) corresponding to the selected point 82 as described above.

If the received power value P _bin of the point 82 is smaller than the minimum receivable power P _{min that} can be communicated, an arbitrary point 83 between the points 81 and 82 is used to search . And calculates the reception power value P _bin of the _bin (BIN) corresponding to the point 83 thus selected.

When the received power value P _bin corresponding to point 85, as by repeating the process as described above shown in the Figures is similar to the call minimum received power (P _min) as possible, the distance to the point (85) at the base station Becomes cell coverage.

The cell coverage prediction algorithm using the above search technique can considerably save the execution time since it does not need to calculate the received power value for all bins between the calculation radius (d _max ) in the base station, There is an advantage that a more accurate prediction value can be obtained than the conventional cell coverage prediction algorithm.

9 is an explanatory diagram of a cell coverage estimation method according to another embodiment of the present invention.

First, various parameters necessary for estimating the cell coverage are set by using search methods such as calculation radius (d _max ), minimum reception power (P _min ), size of beans, number of radials, etc. (91) A cell coverage bean is searched for using the search technique (92).

If cell coverage bin selection has not been completed for all radials (93), then cell coverage bin is stored (94), then radial is set (95) The procedure is repeated from the step 92 of searching for the cell coverage bean using the search technique for the radial. On the other hand, if cell coverage bin selection for all radials is completed, that is, cell coverage bean search is performed from the first radial to the final radial, then all selected cell coverage bins are concatenated (96) to finally obtain a desired cell coverage area (97).

10 is a detailed flowchart of a process 92 for searching for a cell coverage bean according to another embodiment of the present invention.

First, a point between a base station and a calculation radius (d _max ) is selected by using a search technique (101), a received power value (P _bin ) of a _bin corresponding to a selected point is calculated (102) (P _bin ) and a minimum receivable power (P _min ) that can be communicated (103).

Then, it is determined whether the difference value between the two calculated values is smaller than a predetermined threshold value (a difference value for determining the corresponding cell to be cell coverage) (104). If the difference value between the two values is not smaller than the threshold value, (102) of calculating a received power value (P _bin ) of a bean corresponding to a selected point after selecting any one point between points by using the search method again, and if the difference value Is less than the predetermined threshold value, the distance from the base station to the bin of the corresponding point is set to the cell coverage (106).

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. Will be apparent to those of ordinary skill in the art.

The present invention can be used in a wireless network designing system for wireless network design, and it is possible to estimate a service range in a shorter time when a base station is located.

Claims (7)

A cell coverage estimation method applied to a wireless network design system, A first step of searching the LOS (Line Of Sight) path for all radials by reading information about the terrain; A second step of finding a cell coverage area by connecting all the LOS points searched; And The third step of outputting the obtained cell coverage area And estimating the cell coverage. The method according to claim 1, In the first step, A fourth step of reading the GIS (Geographical Information System) data to search the LOS path for the first radial and then determining whether the LOS path search is completed for all the radials; If it is determined that the LOS path search has not been completed for all the radials, it is determined that the LOS path is stored and the next radial is set, step; And As a result of the determination of the fourth step, when the LOS path search is completed for all radials, the sixth step of performing the second step And estimating the cell coverage. A cell coverage estimation method applied to a wireless network design system, A first step of searching a cell coverage bean using a search technique for all radials after setting necessary parameters for estimating cell coverage using a search technique; A second step of obtaining a cell coverage area by connecting all the cell coverage bins searched; And The third step of outputting the obtained cell coverage area And estimating the cell coverage. The method of claim 3, In the first step, A fourth step of setting various parameters necessary for estimating cell coverage using a search technique; A fifth step of determining whether cell coverage bin selection for all radials is completed after searching for cell coverage beans using a search technique for the first radial; If it is determined that the cell coverage bean selection has not been completed for all the radial cells, the cell coverage bean is stored, and the next cell radius is set, and then the cell coverage bean is searched for in the fifth step. Step 6; And As a result of the fifth step, if cell coverage bean selection is completed for all radials, a seventh step of performing the second step And estimating the cell coverage. The method according to claim 3 or 4, The process of searching a cell coverage bean using the search technique for the radial includes: An eighth step of calculating a reception power value (P _bin ) of a _bin corresponding to a selected point after selecting a point between the base station and the calculation radius (d _max ) using a search technique; A ninth step of determining whether a difference between the calculated reception power value (P _bin ) and a minimum receivable power (P _min ) that can be communicated is smaller than a predetermined threshold value after calculating the difference value; If it is determined that the difference value between the two values is not smaller than the threshold value as a result of the determination in step 9, an arbitrary point between the immediately selected points is selected using the search technique, 10) of repeating the process of calculating the value (P _bin ); And If it is determined in step 9 that the difference between the two values is less than the threshold value, And estimating the cell coverage. The method according to claim 3 or 4, The search technique, (Bi-Section) search method. The method according to claim 3 or 4, Wherein the parameter comprises: Calculating a radius (d _max), the cell coverage estimation method comprising the number and size of the radial minimum received power (P _min), empty.