JP2006191699A - Wireless base station arrangement method - Google Patents

Abstract

An installation location of a wireless base station capable of communicating with many wireless terminal stations is estimated in advance according to the situation of a region where the wireless base station is actually installed.
In a radio base station arrangement method of a radio communication system in which a plurality of radio base stations are arranged in a service area and communicate with a radio terminal station, surroundings are made at each point of a radio cell formed by each radio base station. The presence / absence of line-of-sight with respect to all the radio base stations existing in is calculated based on the terrain data and the height data, and the position of the radio base station where the point with the line-of-sight and at least one radio base station is maximum is calculated.
[Selection] Figure 1

Description

The present invention relates to a radio base station for covering a service area without gaps in each radio cell of a plurality of radio base stations in a radio communication system in which a plurality of radio base stations are arranged in a service area to communicate with a radio terminal station The present invention relates to a radio base station arrangement method for determining the position of a radio base station.

Since radio wave propagation of mobile communications is affected by topography, buildings, etc., a region (wireless cell) in which radio waves arrive from a radio base station and can communicate is generally complicated.
Here, the wireless base station can communicate with the wireless base station at a point where the wireless base station is visible, and the wireless base station cannot communicate with the wireless base station at a point where the wireless base station is not visible due to an obstacle (for example, a building). Shall.

At this time, as shown in FIG. 8, a radio base station having a height h1 is installed on a flat ground without any undulations, and an obstacle with a height h2 is located on the same plane ground at a distance d1, d2 from the radio base station. (D1 <d2), even if the obstacle has the same height, the area that is not visible to the radio base station increases as the distance from the radio base station increases.
For this reason, the line-of-sight area gradually decreases according to the distance from the radio base station, and the line-of-sight area expands radially as it goes to the end (cell edge) of the radio cell.
This is shown in FIG.

In addition, as the number of high obstacles increases, the line of sight is more likely to be blocked, and as the distance from the radio base station increases, the area that is visible from the radio base station decreases.
That is, as shown in FIG. 10, a region where there is no line-of-sight due to an obstacle is relatively larger in a middle-high area where there are middle- and high-rise obstacles than in a low-rise area where there are low-rise obstacles.
Here, the small circle indicates the boundary of the visibility rate α, and the large circle indicates the boundary of the visibility rate β (β <α).
In the middle and high-rise areas, the areas with the line-of-sight rates α and β are narrower than in the low-rise areas, and the areas with the line-of-sight are rapidly reduced as the cell edge is reached.

Although it is a radio cell having the above characteristics, when a plurality of radio base stations are arranged in the service area, the radio terminal station only needs to have a line of sight with at least one radio base station. Prospective rate will improve.
If the line-of-sight rate when a plurality of radio cells are arranged overlapping each other is the probability of seeing at least one radio base station, the line-of-sight rate when k radio cells overlap uses a statistical model, Line-of-sight rate when k radio cells overlap = [1− (probability of no line-of-sight from radio base station 1) · (probability of no line-of-sight from radio base station 2) ··· (line-of-sight from radio base station k No probability)].

In the conventional radio base station arrangement method, the distance between the radio base stations is examined so that the radio cell radius and the mutual distance between the radio base stations are examined from the above formula so that the visibility rate at an arbitrary point is at least a predetermined value or more. Is calculated and a wireless base station is installed.
Supervised by Yoshihisa Okumura and Masaaki Shinji, “Basics of Mobile Communications”, first edition, Corona, published October 1, 1986, pp. 188-201

In the conventional radio base station arrangement method, a statistical model is set to calculate the visibility rate.
In this case, the situation of the area where the radio base station is actually installed cannot be taken into consideration, and it is difficult to optimize the installation location of the radio base station.

The present invention can estimate the installation location of a radio base station that can communicate with many radio terminal stations in advance according to the situation of the area where the radio base station is actually installed, and can communicate with the radio base station within the service area. An object of the present invention is to provide a radio base station arrangement method that increases the number of radio terminal stations.

The invention according to claim 1 is a radio base station arrangement method of a radio communication system in which a plurality of radio base stations are arranged in a service area to communicate with a radio terminal station, and a radio cell formed by each radio base station Based on the terrain data and height data, whether or not there is a line of sight with respect to all the radio base stations existing at each point is deemed to be visible if there are no obstacles on the straight line connecting each point and the radio base station. If there is an obstacle, it is calculated that there is no line of sight, and the position of the radio base station where the number of points with at least one radio base station and the line of sight is maximized is calculated.

According to a second aspect of the present invention, there is provided a radio base station arrangement method of a radio communication system in which a plurality of radio base stations are arranged in a service area to communicate with a radio terminal station. If there are no obstacles on the straight line connecting each point and the radio base station based on the terrain data and the height data, whether or not there is a line of sight with respect to all the radio base stations existing in the surrounding area at each point It is assumed that there is a line of sight, and if there is an obstacle, it is calculated that there is no line of sight.

According to the radio base station arrangement method of the present invention, a point using at least one radio base station and a line of sight from each point of the radio cell is maximized by calculation using the topographic data and height data of the area where the radio base station is installed. The position of the radio base station can be estimated by approximation.
Thereby, the position of the radio base station can be optimized in consideration of the characteristics of the area where the radio base station is actually installed, and the number of radio terminal stations that can communicate with the radio base station can be increased.

FIG. 1 shows the basic principle of the radio base station arrangement method of the present invention.
Here, it is shown that when one radio base station is moved in an area where the radio cells formed by the two radio base stations are overlapped, at least one radio base station and a point of view increase.

In FIG. 1 (1), in the area where the radio cells formed by two radio base stations are overlapped, the areas that are visible from each radio base station (AP) overlap, and at least one radio base station and The ratio of the point with the prospect is low.
In Fig. 1 (2), the position of one radio base station is moved slightly to reduce duplication of areas that are visible from each radio base station. Indicates an increasing state.
In this way, the ratio of the point of view differs from that of at least one radio base station depending on the installation location of the radio base station.

FIG. 2 shows a first embodiment of the radio base station arrangement method of the present invention.
First, the initial position of each radio base station (AP) is determined (S11).
Next, a fixed radio base station and a moving radio base station are determined (S12).
Next, n installation position candidates for the moving radio base station are determined (S13).
Next, at the first installation position of the moving radio base station, whether or not there is a prospect with at least one radio base station at each point in the radio cell formed by each radio base station as shown in FIG. (S14).
This calculation is performed using a computer that has input the topographic data and height data of the area where the radio base station is located.

Next, the moving radio base station is shifted to the second installation position, and similarly, it is calculated whether or not there is a line of sight with at least one radio base station at each point in the radio cell of each radio base station (S15). , S16, S14).
This calculation is repeated n times while moving the radio base station, and finally, the position of the radio base station that maximizes the ratio of at least one radio base station and a point of view is selected (S17).

FIG. 4 shows a second embodiment of the radio base station arrangement method of the present invention.
First, the initial position of each radio base station (AP) is determined (S21).
Next, a fixed radio base station and a moving radio base station are determined (S22).
Next, n installation position candidates for the moving radio base station are determined (S23).
Next, at the first installation position of the moving radio base station, as shown in FIG. 5, at least one radio at each point in the area surrounded by the two outer peripheral lines of the radio cell formed by each radio base station. It is calculated whether there is a prospect with the base station (S24).

Next, the moving radio base station is shifted to the second installation position, and at least one radio at each point in the area surrounded by the two outer peripheral lines of the radio cell formed by each radio base station. It is calculated whether or not there is a prospect with the base station (S25, S26, S24).
This calculation is repeated n times while moving the radio base station, and finally, the position of the radio base station that maximizes the ratio of at least one radio base station and a point of view is selected (S27).
In this embodiment, the calculation time can be shortened by limiting the region for calculating the presence / absence of line-of-sight to the outer periphery of the radio cell.

FIG. 6 shows a third embodiment of the radio base station arrangement method of the present invention.
First, the initial position of each radio base station (AP) is determined (S31).
Next, a fixed wireless base station and a moving wireless base station are determined (S32).
Next, n installation position candidates for the moving radio base station are determined (S33).
Next, at the first installation position of the moving radio base station, it is calculated whether or not there is a line of sight with at least one radio base station at two points in the radio cell formed by each radio base station (S34). ).
This calculation method is shown in FIG.

As shown in FIG. 6 (2) and FIG. 7, a line is drawn toward the circumference 1 and the circumference 2 around the radio base station, and two points on the circumference 1 and the circumference 2 are determined (S41). ) The presence / absence of visibility at two points is calculated (S42).
If it is calculated that there is a line of sight at these two points, it is estimated that other points between them are also sighted (S43).
If it is calculated that there is no line of sight at these two points, it is estimated that there is no line of sight at other points in between (S44).
If it is calculated that there is a line of sight at one of the two points, recalculation is performed with the interval between the two points narrowed (S45).

Next, shift the moving radio base station to the second installation position, and calculate whether there is a line of sight with at least one radio base station at two points in the radio cell formed by each radio base station. (S35, S36, S34).
This calculation is repeated n times while moving the radio base station, and finally, the position of the radio base station that maximizes the ratio of at least one radio base station and a point of view is selected (S37).
In the present embodiment, the calculation time can be reduced by estimating the presence / absence of line-of-sight from two points of the wireless cell.

The figure which shows the basic principle of the radio base station arrangement | positioning method of this invention. The flowchart which shows the process sequence of 1st Embodiment of the radio base station arrangement | positioning method of this invention. The figure which shows the calculation range of 1st Embodiment of the wireless base station arrangement | positioning method of this invention. The flowchart which shows the process sequence of 2nd Embodiment of the radio base station arrangement | positioning method of this invention. The figure which shows the calculation range of 2nd Embodiment of the wireless base station arrangement | positioning method of this invention. The flowchart which shows the process sequence of 3rd Embodiment of the radio base station arrangement | positioning method of this invention. The figure which shows the calculation range of 3rd Embodiment of the wireless base station arrangement | positioning method of this invention. The figure which shows the relationship between the distance from a base station, and a prospect. The figure which shows the sightline range from a base station. The figure which shows the sightline range from a base station.

Claims (2)

In a radio base station arrangement method of a radio communication system in which a plurality of radio base stations are arranged in a service area to communicate with a radio terminal station,
At each point of the radio cell formed by each radio base station, the presence / absence of visibility to all the radio base stations existing in the vicinity is connected based on the terrain data and the height data, and each point and the radio base station are connected. If there is no obstacle on the straight line, it is assumed that there is a line of sight, and if there is an obstacle, it is calculated that there is no line of sight. A wireless base station arrangement method. In a radio base station arrangement method of a radio communication system in which a plurality of radio base stations are arranged in a service area to communicate with a radio terminal station,
Based on the terrain data and the height data, the respective points and the radio base stations indicate whether or not there is a line of sight with respect to all the radio base stations existing at each point in the outer peripheral portion of the radio cell formed by each radio base station. If there is no obstacle on the straight line connecting, calculate that there is a line of sight, and if there is an obstacle, calculate that there is no line of sight, and calculate the position of at least one radio base station and the radio base station that has the maximum number of sight lines And a radio base station arrangement method.