JP2017200034A - Method, device and program for designing station establishment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain station establishment design enabling, if a base station stalls due to a disaster, a failure, etc., another base station to back up to the possible extent.SOLUTION: A station establishment design includes: a step 1 which, based on a propagation loss amount between each of a plurality of base station candidate points and a plurality of area evaluation points, generates the list of the base station candidate points capable of radio connection for each area evaluation point; a step 2 which, for an area evaluation point having only one base station candidate point capable of radio connection, selects the base station candidate point concerned, as a base station installation location; and a step 3 which, for each base station candidate point which is not yet selected in the step 2, calculates an evaluation value M according to the number of the area evaluation points capable of radio connection and a base station failure occurrence rate, so as to select a base station candidate point, which has a maximum evaluation value M, to be the base station installation location. The processing of the step 3 is repeated until all area evaluation points in the list come to be radio connectable to any one of the base station candidate points.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an apparatus for determining an installation location of a base station forming a cell in a wireless communication system in which a plurality of communication areas (cells) formed by a single base station are arranged to construct a communication service area. The present invention relates to a station design method, a station design apparatus, and a station design program.

  Conventionally, in a wireless communication system in which a plurality of base stations are arranged and a continuous communication service area is constructed by cells formed by the respective base stations, as a technique for supporting base station placement design, for example, Patent Document 1 It has been known. Here, as an optimal base station arrangement pattern, a placement station design method for searching for a combination of base station candidate points in which all area evaluation points become communicable areas and the number of base station candidate points is minimized is disclosed. ing. Specifically, an evaluation function that defines a larger value as the number of area evaluation points included in the communicable area increases and the number of base station candidate points decreases, and a genetic algorithm is used to select an evaluation function. This is a station design method for determining the optimal base station arrangement.

  Unlike the cited document 1, the technique of the cited document 2 realizes the station placement design considering the base station cooperation, and realizes a smooth handover or the like for the mobile radio communication system. In the technique of the cited document 3, the dispersion | variation in the throughput between cells is suppressed by the station location design.

JP 2001-285923 A JP 2010-206314 A JP 2009-049758 A

  The placement station design methods disclosed in Patent Documents 1 to 3 realize a required communication service area with a minimum number of base stations, realize a smooth handover between cells, and suppress variations in throughput between cells. The purpose was to do.

  For example, in the placement design method of Patent Document 1, as shown in FIG. 8, when there are 10 area evaluation points (◯) for 5 base station candidate points (Δ) A to E, The combination of the minimum base station candidate points that can communicate with the area evaluation point is searched. Pattern 1 in FIG. 8 (1) is a combination of base station candidate points A and D, and the number of area evaluation points included in a single communication area is 4 and 5, respectively. Area evaluation included in a common area The number of points is one. Pattern 2 in FIG. 8 (2) is a combination of base station candidate points B and C. The number of area evaluation points included in a single communication area is 2 and 2, respectively, and area evaluation included in a common area. The number of points is six. In addition, there are combinations of base station candidate points A and C, base station candidate points B and D, and base station candidate points B and E.

  Thus, in patterns 1 and 2, the number of area evaluation points included in a single communication area of each base station candidate point is greatly different. The area evaluation points included in this single communication area are immediately unable to communicate when the base station stops operating due to a disaster or failure. On the other hand, the area evaluation point included in the common area can be connected to one of the two base stations, and even if the operation of the currently connected base station stops, communication can be performed by changing the connection to the other base station. Can continue.

  From the above viewpoint, when it is assumed that the operation of a base station will be stopped due to a disaster or failure, the area evaluation score that disables communication is minimized and the area evaluation score that can be backed up by another base station is maximized. It can be said that the pattern 2 is more preferable than the pattern 1 as the placement pattern.

  The present invention provides a station placement design method, a station placement design apparatus, and a station placement design program for realizing a station placement design that enables backup by other base stations as much as possible even when a base station stops functioning due to a failure or the like due to a disaster. The purpose is to provide.

  In a station design method for selecting a base station installation position from a plurality of base station candidate points so that each of the plurality of area evaluation points can be wirelessly connected to at least one base station candidate point. Step 1 for creating a list of base station candidate points that can be wirelessly connected for each area evaluation point based on the amount of propagation loss between each of the plurality of base station candidate points and the plurality of area evaluation points, and wireless connection possible For area evaluation points that have only one base station candidate point, wireless connection is possible for each base station candidate point that is not selected in step 2 in which the base station candidate point is selected as the base station installation position. Calculating an evaluation value M according to the number of area evaluation points and the base station failure occurrence rate, and selecting a base station candidate point that maximizes the evaluation value M as a base station installation position; All areas Until valence point is wirelessly connectable to one of the base station candidate point repeats the process of Step 3.

In the station design method of the first invention, the evaluation value M of the area evaluation point that can be wirelessly connected for each unselected base station candidate point in step 3 is:
M = m (1) + Σ (m (i) / i) · Pf
M (1) is the number of area evaluation points that can be wirelessly connected only to the base station candidate points to be evaluated,
m (i) / i is the number of base station candidate points to be evaluated and i pieces of base station candidate points already selected as base station installation positions (2 ≦ i ≦ n, n is 2 or more and the number of base station candidate points or less. (Integer) base station candidate points are the number of area evaluation points that can be wirelessly connected, and Pf is a base station failure occurrence probability.

  In the station placement design method according to the first aspect, when there are a plurality of base station candidate points at which the evaluation value M of the area evaluation points that can be wirelessly connected is the maximum value for each unselected base station candidate point in step 3 Then, the base station candidate point that minimizes the total propagation loss amount between the plurality of base station candidate points and the area evaluation points that are wirelessly connected to each other is selected.

  According to a second aspect of the present invention, there is provided a station design apparatus for selecting a base station installation position from a plurality of base station candidate points so that each of the plurality of area evaluation points can be wirelessly connected to at least one base station candidate point. Collects the amount of propagation loss between each of the plurality of base station candidate points and the plurality of area evaluation points, and creates a list of base station candidate points that can be wirelessly connected for each area evaluation point based on the propagation loss amount For the area evaluation point that has only one base station candidate point that can be wirelessly connected to the list creation means, the base station candidate point is selected as the base station installation position, and wireless communication is performed for each unselected base station candidate point. Base station selection means for calculating an evaluation value M according to the number of connectable area evaluation points and a base station failure occurrence rate, and selecting a base station candidate point having the maximum evaluation value M as a base station installation position; Prepare.

  According to a third aspect of the present invention, there is provided a station placement design program for causing a computer to execute the steps of the first invention and selecting a base station installation position from a plurality of base station candidate points.

  In the present invention, the base station is selected so that more base stations can be wirelessly connected as viewed from the area evaluation point while the area evaluation point can be wirelessly connected with as few base stations as possible. Even if some of the base stations become inoperative, it is possible to back up at another base station.

It is a flowchart which shows the process sequence example of the station location design method of this invention. It is a figure which shows the process example of step S1, S2. It is a figure which shows the process example of step S3, S4. It is a figure which shows the process example of step S6. It is a figure which shows the process example of step S6 of the 2nd time. It is a figure which shows the process example of step S6 of the 3rd time. It is a figure which shows the Example structure of the station location design apparatus of this invention. It is a figure which shows the example of base station selection by the conventional station placement design method.

FIG. 1 shows an example of the processing procedure of the station placement design method of the present invention.
In FIG. 1, base station candidate points and area evaluation points are designated (S1), and base stations that can be wirelessly connected for each area evaluation point based on the amount of propagation loss between each base station candidate point and each area evaluation point A list of station candidate points is created (S2). Here, of the designated area evaluation points, the area evaluation points that do not have any wirelessly connectable base station candidate points are deleted from the list. Next, it is determined whether there is an area evaluation point that has only one base station candidate point that can be wirelessly connected from the list (S3), and an area evaluation point that has only one base station candidate point that can be wirelessly connected. Is present, a base station candidate point that can be wirelessly connected to the area evaluation point is selected as a base station installation position (S4). If there is no area evaluation point, the process of S4 is passed and the process proceeds to the next.

  Next, it is determined whether or not all area evaluation points can be wirelessly connected to the base station candidate points (S5). If there are area evaluation points whose wireless connection is undetermined, the process proceeds to the next step S6 and must remain. If finished. Here, the remaining area evaluation points have two or more base station candidate points that can be wirelessly connected.

Next, for each unselected base station candidate point, an evaluation value M corresponding to the number of wirelessly connectable area evaluation points and the base station failure occurrence rate is calculated as follows, and the base having the largest evaluation value M is calculated. Station candidate points are selected as base station installation positions (S6).
M = m (1) + Σ (m (i) / i) · Pf
Here, m (1) is the number of area evaluation points that can be wirelessly connected only to the base station candidate points. m (i) / i is i (2 ≦ i ≦ n, where n is 2 or more and less than the number of base station candidate points) including the base station candidate point and the base station candidate point already selected as the base station installation position. (Integer) base station candidate points are the number of area evaluation points that can be wirelessly connected. For example, if there are m (2) area evaluation points wirelessly connectable to two base station candidate points, the area evaluation points Is calculated as m (2) / 2, and m (2) / 2 to m (n) / n are added. Pf is a base station failure occurrence probability, for example, a probability that a power failure occurs according to the scale of the disaster and the function as a base station stops, and is set in consideration of the presence or absence of a standby power supply or the like.

  Next, the process returns to step S5, and the process of step S6 is repeated until all area evaluation points can be wirelessly connected to the base station candidate points.

Hereinafter, processing examples of steps S1 to S6 will be described with reference to specific examples illustrated in FIGS.
FIG. 2 shows a processing example of steps S1 and S2. Base station candidate points A to F and surrounding area evaluation points are designated. Based on the propagation loss amount between each base station candidate point and each area evaluation point, a list of base station candidate points that can be wirelessly connected is created for each area evaluation point.

  FIG. 3 shows a processing example of steps S3 and S4. An area evaluation point having only one base station candidate point that can be wirelessly connected is indicated by a numerical value 1 in a circle, and an area evaluation point having two or more base station candidate points that can be wirelessly connected is indicated by a circle. Here, an area evaluation point having only one base station candidate point that can be wirelessly connected and base station candidate points A and D that can be wirelessly connected are selected as base station installation positions. At this time, there are a total of 5 area evaluation points that can be wirelessly connected to the base station candidate point A, and there are a total of 5 area evaluation points that can be wirelessly connected to the base station candidate point D. Wireless connection to both the station candidate points A and D is possible. At this time, since a plurality of area evaluation points that are not wirelessly connected to the base station candidate points remain, the process proceeds to step S6.

  According to the present invention, the area evaluation points can be wirelessly connected to at least one base station candidate point by the processing in steps S3 and S4, and the necessary minimum base station candidate points are obtained by the processing in steps S5 and S6. It is characterized in that the number of area evaluation points that can be wirelessly connected to the above base station candidate points is increased as much as possible to enable backup when a base station failure occurs.

  FIG. 4 shows a processing example of step S6. Area evaluation points that can be wirelessly connected only to unselected base station candidate points B, C, E, and F are indicated by a numerical value 1 within ○, and the base station candidate that has already been selected as the base station installation position Area evaluation points that can be wirelessly connected to two or more base station candidate points including points A and D are indicated by the number of base station candidate points within ○.

In the case of the base station candidate point B, four area evaluation points that can be wirelessly connected only to the base station candidate point B, two area evaluation points that can be wirelessly connected to the base station candidate points A and B, and base station candidate points There is one area evaluation point that can be wirelessly connected to A, B, and D, and the evaluation value M (B) is calculated as follows.
M (B) = 4 + (2/2 + 1/3) · Pf = 4 + 1.33 Pf
Similarly, the evaluation value M (C) of the base station candidate point C, the evaluation value M (E) of the base station candidate point E, and the evaluation value M (F) of the base station candidate point F are as follows.
M (C) = 3 + (0) · Pf = 3
M (E) = 5 + (3/2 + 1/3) · Pf = 5 + 1.83 Pf
M (F) = 5 + (0) · Pf = 5

  Therefore, if the base station failure occurrence probability Pf exceeds 0, the base station candidate point E having the maximum evaluation value M is selected. At this point, since there are still area evaluation points that are not wirelessly connected to the base station candidate points, the process of step S6 for the second time is performed.

  FIG. 5 shows a processing example of step S6 for the second time. Area evaluation points that can be wirelessly connected only to unselected base station candidate points B, C, and F are indicated by a numerical value 1 within ○, and the base station candidate point A that has already been selected as the base station installation position , D, and E, area evaluation points that can be wirelessly connected to two or more base station candidate points are indicated by the number of base station candidate points within ○.

The evaluation value M (B) of the base station candidate point B, the evaluation value M (C) of the base station candidate point C, and the evaluation value M (F) of the base station candidate point F are as follows.
M (B) = 1 + (4/2 + 1/3 + 1/4) · Pf = 1 + 2.58Pf
M (C) = 2 + (1/2) · Pf = 2 + 0.5Pf
M (F) = 1 + (4/2) · Pf = 1 + 2Pf

Here, if Pf = 0.1,
M (B) = 1 + 2.58Pf = 1.258
M (C) = 2 + 0.5Pf = 2.05
M (F) = 1 + 2Pf = 1.2
Thus, as shown in FIG. 5 (1), the base station candidate point C that maximizes the evaluation value M is selected, and all area evaluation points can be wirelessly connected.

On the other hand, if Pf = 0.5,
M (B) = 1 + 2.58Pf = 2.29
M (C) = 2 + 0.5Pf = 2.25
M (F) = 1 + 2Pf = 2
As shown in FIG. 5 (2), the base station candidate point B with the maximum evaluation value M is selected, and there are still area evaluation points that are not wirelessly connected to the base station candidate point. The process of step S6 is performed.

  FIG. 6 shows a processing example of step S6 for the third time. Area evaluation points that can be wirelessly connected only to unselected base station candidate points C and F are indicated by a numerical value 1 within ○, and the base station candidate points A and B that have already been selected as base station installation positions , D, and E, area evaluation points that can be wirelessly connected to two or more base station candidate points are indicated by the number of base station candidate points within ○.

The evaluation value M (C) of the base station candidate point C and the evaluation value M (F) of the base station candidate point F are as follows. However, the base station failure occurrence probability Pf is 0.5.
M (C) = 1 + (1/2 + 1/3) · Pf = 1 + 0.83Pf
M (F) = 1 + (2/2 + 2/3) · Pf = 1 + 1.66Pf

  Therefore, the base station candidate point F with the maximum evaluation value M is selected, and all the area evaluation points can be wirelessly connected, and the process ends.

  Thus, base station candidate points A, D, E, and C are selected when Pf = 0.1, and base station candidate points A, D, E, B, and F are selected when Pf = 0.5. That is, when the base station failure occurrence probability Pf is low, four base stations may be installed. However, when the base station failure occurrence probability Pf is high, five base stations are used for backup at the time of failure occurrence. It can be seen that it is desirable to install.

  In the first step S6 shown in FIG. 4, if the base station failure occurrence probability Pf is 0, the maximum value of the evaluation value M is 5, and the base station candidate points E and F have the same value. In that case, for example, the one having the smaller total propagation loss amount between the base station candidate points E and F and the area evaluation points wirelessly connected may be selected. As a result, when the base station candidate point F is selected, the base station candidate point B is selected next, and as a result, the base station candidate points A, D, F, and B are selected. If there are three or more base station candidate points with the maximum evaluation value M, the total propagation loss amount between the plurality of base station candidate points and each of the area evaluation points wirelessly connected is What is necessary is just to select the base station candidate point which becomes the minimum.

  In the above description, each base station candidate point is assumed to be an omnidirectional antenna. However, the relationship with each area evaluation point may be processed in consideration of the antenna directivity.

FIG. 7 shows the configuration of an embodiment of the station placement design apparatus of the present invention.
In FIG. 7, the station placement design apparatus of the present invention includes a base station candidate point list creation unit 11, a base station candidate point list storage unit 12, and a base station selection unit 13. The base station candidate point list creation unit 11 includes information on base station candidate points and area evaluation points from the base station candidate point / area evaluation point database 21, and a plurality of base station candidate points calculated by the propagation loss amount calculation unit 22. Enter information on the amount of propagation loss between each of multiple area evaluation points, create a list of base station candidate points that can be wirelessly connected for each area evaluation point with a propagation loss amount of a predetermined value or more, and base station candidates Store in the point list storage unit 12. In this base station candidate point list, one or more base station candidate points that can be wirelessly connected are recorded for each area evaluation point, and area evaluation points that cannot be wirelessly connected to the base station candidate point are excluded.

  The base station selection unit 13 uses the base station candidate point list stored in the base station candidate point list storage unit 12 and the base station failure occurrence rate information set from the outside, according to the above-described procedure. The optimal base station installation position is selected from the candidate points. That is, for an area evaluation point having only one base station candidate point that can be wirelessly connected, the base station candidate point is selected as the base station installation position, and the wirelessly connectable area for each unselected base station candidate point An evaluation value M corresponding to the number of evaluation points and the base station failure occurrence rate is calculated, and a base station candidate point that maximizes the evaluation value M is selected as a base station installation position.

  Each processing step shown in FIG. 1 can be realized by a computer program that causes a computer to function as a station location design apparatus. This computer program can be stored in a computer-readable storage medium or provided via a network.

A, B, C, D, E, F Base station candidate points 11 Base station candidate point list creation unit 12 Base station candidate point list storage unit 13 Base station selection unit 21 Base station candidate point / area evaluation point database 22 Propagation loss amount Calculation part

Claims (5)

In the station design method of selecting a base station installation position from among a plurality of base station candidate points so that a plurality of area evaluation points can be wirelessly connected to at least one base station candidate point,
Creating a list of base station candidate points that can be wirelessly connected for each area evaluation point, based on the amount of propagation loss between each of the plurality of base station candidate points and the plurality of area evaluation points;
For the area evaluation point having only one base station candidate point that can be wirelessly connected, selecting the base station candidate point as the base station installation position; and
For each base station candidate point that is not selected in step 2, an evaluation value M is calculated according to the number of area evaluation points that can be wirelessly connected and the base station failure occurrence rate, and the base station candidate that maximizes the evaluation value M Selecting a point as the base station installation position, and repeating the process of step 3 until all area evaluation points in the list are wirelessly connectable to any one of the base station candidate points. Characterized station design method. In the station location design method according to claim 1,
The evaluation value M of the area evaluation point that can be wirelessly connected for each of the unselected base station candidate points in Step 3 is:
M = m (1) + Σ (m (i) / i) · Pf
M (1) is the number of area evaluation points that can be wirelessly connected only to the base station candidate points to be evaluated,
m (i) / i is the number of base station candidate points to be evaluated and i pieces of base station candidate points already selected as base station installation positions (2 ≦ i ≦ n, n is 2 or more and the number of base station candidate points or less. An integer) base station candidate point is the number of area evaluation points that can be wirelessly connected, and Pf is a base station failure occurrence probability. In the station location design method according to claim 1,
If there are a plurality of base station candidate points at which the evaluation value M of the area evaluation points that can be wirelessly connected is the maximum value for each of the unselected base station candidate points in step 3, the plurality of base station candidate points A base station design method comprising: selecting a base station candidate point that minimizes a total value of propagation losses between the area evaluation points that are wirelessly connected to each other. In the station designing device for selecting a base station installation position from among a plurality of base station candidate points so that a plurality of area evaluation points can be wirelessly connected to at least one base station candidate point,
Collecting a propagation loss amount between each of the plurality of base station candidate points and the plurality of area evaluation points, and based on the propagation loss amount, a list of base station candidate points that can be wirelessly connected for each area evaluation point A list creation means to be created;
For an area evaluation point having only one base station candidate point that can be wirelessly connected, the base station candidate point is selected as a base station installation position, and an area evaluation point that can be wirelessly connected for each unselected base station candidate point Base station selection means for calculating an evaluation value M according to the number of base stations and the base station failure occurrence rate, and selecting a base station candidate point with the maximum evaluation value M as a base station installation position. Station design device.   A station design program for causing a computer to execute each step according to claim 1 and selecting a base station installation position from among a plurality of base station candidate points.

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