KR100248670B1 - Method of estimating cell coverage in the wireless-network design system - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

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

2. The technical problem to be solved by the invention

According to the present invention, in order to improve the calculation speed of the radio wave analysis function implemented in the wireless network design system, the cell coverage may be roughly estimated in advance using LOS (Line Of Sight), or may be applied to all bins corresponding to each radial. Cell coverage estimation method that estimates the cell coverage in advance by calculating the received signal power only for the minimum bins needed for cell coverage calculation using arbitrary search techniques such as binary search scheme, etc. The purpose is to provide

3. Summary of Solution to Invention

The present invention includes a first step of reading information about a terrain and searching for a line of sight (LOS) path for all radials; A second step of concatenating all discovered LOS points to obtain a service area; And a third step of outputting the obtained service area, so that the service range can be estimated within a shorter time in setting the location of the base station.

4. Important uses of the invention

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

Description

Cell Coverage Estimation Method in Wireless Network Design System

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

First, when the terms used in the present invention are defined, LOS (Line Of Sight) refers to a situation in which there is no obstacle on the straight traveling path of radio waves in the radio wave analysis.

The Geographical Information System (GIS) is a general term for a system for handling a vast amount of feature and terrain information for Facilities Management (FM) and efficient management of geographic information. Most of them are digitally handled because they are designed and managed using a computer.

The GIS for the design of the wireless network should contain the information of the terrain and features, and in particular, it should be able to handle the information such as the location, altitude, direction, material of the building and the characteristics of the terrain (Morphology).

Digital Terrain Model (DTM) is a digital terrain model that digitizes the profile of a terrain. The DTM is a terrain data model that stores height values and property information for each grid scale after creating grids with proper spacing.

Cell coverage refers to an area where a wireless base station provides a service. When using an omnidirectional antenna, a cell coverage may be illustrated as a circle having a radius d about the base station as shown in FIG. 1. However, the actual cell coverage has an irregular shape due to the terrain and the characteristics of the building. The radio signal transmitted from the base station weakens as it moves away from the base station. If the signal falls below a certain signal power, the call becomes impossible, and this point becomes the cell coverage boundary.

Cell planning refers to the entire area to provide wireless communication services (personal communication service, mobile communication service, city-2 service, etc.) based on the analysis of cell coverage for each base station as shown in FIG. By appropriately placing several base stations in the network, any point in the service area can be provided with service from more than one base station. In this case, the investment cost is reduced as the number of base stations required to cover the service area is reduced as much as possible. On the other hand, if the distance between base stations is too far, a shaded area of radio waves may occur, making a call impossible. Therefore, it is necessary to determine the location of an optimal base station through accurate analysis of the cell coverage of one base station. In general, cell coverage analysis of a base station uses a wireless network design system. The wireless network design system predicts the received electric field strength of each point of the base station by using the GIS data.

Most wireless network design systems that are currently commercialized for wireless carriers provide basic functions for radio wave analysis, but most of them have a basic problem of requiring a large amount of computation during radio wave analysis.

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

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

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

Therefore, the smaller the bin, the more accurate coverage can be obtained, but the disadvantage is that the calculation speed becomes slow. The size of the bin can be arbitrarily set by the user to determine the accuracy and speed of the prediction.

The calculation for each bin first establishes a radial 33 over 360 degrees in an angle close enough to pass all bins. Then, the received electric field strength is calculated for all the bins over each radial. For example, the bins spanning radial 5 (34) in FIG. 3 are bin 1 to bin 5 (35), calculating the received field strength for all five bins. At this time, the received electric field strength for each bin is obtained using GIS data and propagation models provided by the system.

Repeating this process for all radials yields the received field strength P _bin for all bins within the calculation radius d _max . And, the terminals of all the wireless communication systems have the minimum receive power (P _min ) that can be talked. Comparing the minimum received power P _min with the received field strength calculations for each bin, the blank areas having a value greater than P _min form cell coverage.

In the conventional cell coverage estimation method as described above, since accurate cell coverage is obtained, unnecessary calculation is further performed for all bins within the calculation radius d _max , so that even when only rough cell coverage is calculated, It requires a lot of execution time. On the other hand, in order to speed up execution, the size of the bin may be increased, but in this case, the accuracy may be deteriorated. Therefore, the conventional cell coverage estimation method is very unsuitable for use when rough cell coverage calculation is required.

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

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

In the case of designing a wireless network using the conventional radio wave analysis method as described above, not only a long time is required for the design of the wireless network, but also there is a problem that a lot of difficulties arise in the post-management such as relocation.

SUMMARY OF THE INVENTION An object of the present invention devised to solve the above problems is a cell which estimates cell coverage in advance using line of sight (LOS) to improve the calculation speed of a radio wave analysis function implemented in a wireless network design system. It is to provide a coverage estimation method.

In addition, another object of the present invention, in order to improve the calculation speed of the radio wave analysis function implemented in the wireless network design system, a binary search technique rather than calculating the received signal power for all bins corresponding to each radial The present invention provides a cell coverage estimation method for estimating the cell coverage in advance by calculating the received signal power only for the minimum bins necessary for the cell coverage calculation using an arbitrary search technique.

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

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

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

Figure 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 according to an embodiment of the present invention. FIG.

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

8 is a diagram for explaining a cell coverage estimation method according to another embodiment of the present invention;

9 is a diagram for explaining a cell coverage estimation method according to another embodiment of the present invention;

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

* Explanation of symbols for the main parts of the drawings

51: computer 52: input device

53: output device

In order to achieve the above object, the present invention provides a method for estimating cell coverage applied to a wireless network design system, the method comprising: a first step of searching for a line of sight (LOS) path for all radials by reading information about a terrain; A second step of concatenating all of the searched LOS points to obtain a cell coverage area; And a third step of outputting the obtained cell coverage area.

In order to achieve the above object, the present invention provides a cell coverage estimation method applied to a wireless network design system, in which a search technique is used for all radials after setting necessary parameters for estimating cell coverage using a search technique. A first step of searching for a cell coverage bin; A second step of concatenating all found cell coverage bins to obtain a cell coverage area; And a third step of outputting the obtained cell coverage area.

Hereinafter, with reference to the accompanying drawings will be described an embodiment according to the present invention;

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 a location of a base station, a mouse, and an output device 53 for showing and outputting a final service area. It has a printer and a plotter.

The present invention is basically an algorithm to be implemented in a wireless network design system using a computer. The driving method starts with the position of a mouse as the position of a base station. In other words, when the mouse is positioned at an arbitrary point on the digital map, the position of the points corresponding to the LOS when looking radially from the point is found. This will be described in more detail with reference to FIG. 6 as follows.

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

When trying to find the LOS for each radial in the clockwise direction about the base station (S) as shown in Figure 6, when discussing the LOS for buildings on the same radial, when propagation from the center of the base station to the outside The LOS path is the first building or origin that is greater than the height of the base station.

If LOS is established, the bean is accepted as a service area and the same operation is performed for the remaining radials. As such, if 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 becomes an internal area consisting of these beans.

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

First, read the GIS data (71) to search the LOS path for the first radial (72), then determine whether you have completed the LOS path search for all radials (73), and if you have not completed the LOS path search for all the radials After the searched LOS path is stored (74) and the next radial is set (75), the process is repeated from the process (72) of searching the LOS path for the set radial.

On the other hand, 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, then all LOS points are connected (76) to finally obtain and display the desired cell coverage area (77). .

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

As shown in the figure, the reception power decreases as the radio wave propagates in the base station. Although the selection point is different depending on the type of search technique, the base station first selects a point between the calculation radius d _max . In this case, in the case of a Bi-Section search method, an intermediate point is selected. The received power value P _bin of the _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 callable receive power P _min as shown in FIG. 8, a point 82 between the point 81 and the calculation radius d _max is again provided. Is selected using a search technique. In this case, in the case of a Bi-Section search method, an intermediate point between the point 81 and the calculation radius d _max is selected. The received power value P _bin of the _bin corresponding to the selected point 82 is calculated.

If the received power value P _bin of the point 82 is smaller than the minimum callable received power P _min , the search technique is used again to find any one point 83 between the point 81 and the point 82. Will be selected. The received power value P _bin of the _bin corresponding to the selected point 83 is calculated.

Repeating the above process, when the received power value P _bin corresponding to the point 85 becomes similar to the minimum allowable received power P _min as shown in the figure, the distance from the base station to the point 85 Becomes cell coverage.

The cell coverage prediction algorithm using the above search method can significantly reduce the execution time because the base station does not have to calculate the received power values for all the bins between the calculation radius d _max , and at a relatively given calculation time. With respect to the conventional cell coverage prediction algorithm, there is an advantage that a much more accurate prediction value can be obtained.

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

First, after setting various parameters necessary for estimating cell coverage using a search technique such as a calculation radius (d _max ), a minimum received power (P _min ), the size of a bin, and the number of radials, the first radial is set. The cell coverage bin is searched for using a search technique (92).

Subsequently, it is determined whether the cell coverage bin selection is completed for all the radials (93). If the cell coverage bin selection is not completed for all the radials, the corresponding cell coverage bin is stored (94) and after setting the next radial (95). The radial operation of the radial is repeated from step 92 of searching for a cell coverage bin. On the other hand, when the cell coverage bin selection is completed for all the radials, that is, after performing the cell coverage bin search from the first radial to the last radial, all the selected cell coverage bins are concatenated (96) to finally obtain the desired cell coverage area. Display (97).

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

First, a point between the base station and the calculation radius (d _max ) is selected by using a search technique (101) to calculate the received power value (P _bin ) of the _bin corresponding to the selected point (102), and then the calculated received power A difference value between the value P _bin and the minimum receive power P _{min that} can be talked is calculated (103).

Then, it is determined whether the difference between the calculated two values is smaller than a predetermined threshold (a difference enough to define the bin as the cell coverage) (104). If the difference between the two values is not smaller than the threshold, the immediately selected value is selected. After selecting a random point between the points again using a search method (105), it is repeated from the step 102 of calculating the received power value (P _bin ) of the _bin corresponding to the selected point, and if the difference between the two values If it is less than this predetermined threshold, the base station sets the cell coverage to the bin of the point (106).

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes can be made in the art without departing from the technical spirit of the present invention. It will be apparent to those of ordinary knowledge.

As described above, the present invention is used in a wireless network design system for wireless network design, and has an effect of estimating a service range in a shorter time when setting a location of a base station.

Claims (7)

In the cell coverage estimation method applied to a wireless network design system, A first step of reading information about the terrain and searching for a line of sight (LOS) path for all radials; A second step of concatenating all of the searched LOS points to obtain a cell coverage area; And A third step of outputting the obtained cell coverage area Cell coverage estimation method comprising a. The method of claim 1, The first step is, Reading the Geographical Information System (GIS) data and searching for the LOS path for the first radial and then determining whether to complete the LOS path searching for all the radials; As a result of the determination of the fourth step, if the LOS path search is not completed for all the radials, a fifth step of repeating the process of searching for the LOS path of the fourth step after storing the found LOS path and setting the next radial step; And As a result of the determination of the fourth step, when the LOS path search is completed for all the radials, the sixth step of performing the second step Cell coverage estimation method comprising a. In the cell coverage estimation method applied to a wireless network design system, A first step of searching for a cell coverage bin using a search technique for all the radials after setting a parameter necessary for estimating cell coverage using the search technique; A second step of concatenating all found cell coverage bins to obtain a cell coverage area; And A third step of outputting the obtained cell coverage area Cell coverage estimation method comprising a. The method of claim 3, wherein The first step is, A fourth step of setting various parameters necessary for estimating cell coverage using a search technique; A fifth step of determining whether the cell coverage bin selection is completed for all the radials after searching the cell coverage bins using the search technique for the first radial; As a result of the determination of the fifth step, if the cell coverage bin selection is not completed for all the radials, the cell coverage bin is stored, the next radial is set, and then the process of searching for the cell coverage bin of the fifth step is repeated. Sixth step; And A seventh step of performing the second step if the cell coverage bin selection is completed for all the radials as a result of the determination of the fifth step Cell coverage estimation method comprising a. The method according to claim 3 or 4, The process of searching for a cell coverage bin using the search technique for the radial includes: An eighth step of selecting a point between the base station and the calculation radius d _max using a search technique and calculating a received power value P _{bin of the bin} corresponding to the selected point; A ninth step of calculating whether a difference between the calculated two values is smaller than a predetermined threshold after calculating a difference between the calculated received power value P _bin and the minimum callable received power P _min ; As a result of the determination in the ninth step, if the difference between the two values is not smaller than the threshold, the received power of the bin corresponding to the selected point in the eighth step after selecting a random point between the previously selected points by using a search technique. A tenth step of repeating the process of calculating the value P _bin ; And As a result of the determination in the ninth step, when the difference between the two values is smaller than the threshold, the eleventh step of setting the distance from the base station to the bin of the corresponding point as the cell coverage Cell coverage estimation method comprising a. The method according to claim 3 or 4, The search technique, A cell coverage estimation method, which is a bi-section search technique. The method according to claim 3 or 4, The parameter is A method for estimating cell coverage comprising a radius of calculation (d _max ), a minimum received power (P _min ), a size of bins and a number of radials.

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