WO2021255799A1

WO2021255799A1 - Wireless base station control device, communication recovery method, and program

Info

Publication number: WO2021255799A1
Application number: PCT/JP2020/023478
Authority: WO
Inventors: 真尚岩本; 晃人鈴木; 薫明原田
Original assignee: 日本電信電話株式会社
Priority date: 2020-06-15
Filing date: 2020-06-15
Publication date: 2021-12-23
Also published as: JP7384288B2; JPWO2021255799A1

Abstract

Provided is a wireless base station control device which determines a recovery station for recovering communication in a faulty area created when a wireless base station has failed and a tilt angle for said recovery station, the wireless base station control device comprising: an estimation unit which estimates a radio wave propagation range, without estimating field intensity, for each tilt angle of each recovery station candidate among a plurality of recovery station candidates; and a determination unit that determines, as the recovery station and the tilt angle for said recovery station, a specific combination of a recovery station candidate and tilt angle from among a plurality of combinations of a recovery station candidate and tilt angle, the determination being made on the basis of the proportion of the area covered by the radio wave propagation range within the faulty area.

Description

Radio base station controller, communication rescue method, and program

The present invention relates to a technique for relieving an area where communication is disabled due to a failure of a radio base station in a mobile communication network.

In a mobile communication network, if a wireless base station fails, a communication failure occurs in the area covered by the wireless base station. Therefore, in general, the faulty area is covered (relieved) by a surrounding radio base station (adjacent station). For example, the obstacle area is relieved by controlling the tilt angle of the antenna of the adjacent station.

It is necessary to estimate the radio wave propagation range by the adjacent station in order to determine which area the adjacent station can rescue. As disclosed in Non-Patent Document 1, this estimation is generally performed by electric field strength estimation.

However, in the electric field strength estimation, it takes time to calculate because radio wave interference, propagation loss, etc. are calculated for the three-dimensional space. That is, in the relief of the obstacle area by the conventional technique, the calculation takes time and it is difficult to make a quick relief.

The present invention has been made in view of the above points, and an object of the present invention is to provide a technique capable of promptly relieving a faulty area caused by a failure of a radio base station.

According to the disclosed technology, it is a relief station that relieves communication in a faulty area that occurs when a radio base station fails, and a radio base station control device that determines the tilt angle thereof.
An estimation unit that estimates the radio wave propagation range without estimating the electric field strength for each tilt angle of each relief station candidate in multiple relief station candidates.
From a plurality of combinations of relief station candidates and tilt angles, a combination of a specific relief station candidate and tilt angle is used as the relief station and its tilt angle based on the ratio of the area covered by the radio wave propagation range in the obstacle area. A radio base station controller with a decision-making unit is provided.

According to the disclosed technology, a technology that makes it possible to quickly relieve a faulty area caused by a failure of a radio base station is provided.

It is a block diagram of the system in Embodiment of this invention. It is a figure for demonstrating a sector. It is a figure for demonstrating a sector. It is a block diagram of the radio base station control device. It is a flowchart for demonstrating operation of a radio base station control device. It is a figure which shows d _max and d _min. It is a figure which shows two fan shapes. It is a figure which shows the hardware configuration example of the apparatus.

Hereinafter, an embodiment of the present invention (the present embodiment) will be described with reference to the drawings. The embodiments described below are merely examples, and the embodiments to which the present invention is applied are not limited to the following embodiments.

(Overall system configuration)
FIG. 1 shows an example of the overall configuration of the system according to the embodiment of the present invention. As shown in FIG. 1, the system according to the present embodiment includes a configuration in which a plurality of radio base stations 10 and a radio base station control device 100 are connected to a network 200. The network 200 is, for example, a network including a mobile core network. A communication terminal exists under each radio base station, and each communication terminal wirelessly communicates with the radio base station.

When a certain radio base station 10 fails, a communication failure occurs in the area (failure area) covered by the radio base station 10. In the present embodiment, the radio base station control device 100 executes control so that the communication in the faulty area is covered (relieved) by the surrounding radio base stations (adjacent stations).

In the present embodiment, each radio base station 10 is composed of a plurality of sectors, and each sector is in charge of communication cover in a specific direction. FIG. 2 shows an image of a sector of the radio base station 10. FIG. 2 shows an example in which the radio base station 10 includes three sectors. The sectors may be separated from each other.

One sector is composed of one or more antennas, and each antenna is in charge of the communication cover of a specific area in a certain direction. Since there is a case where only a part of the sectors of the radio base station 10 fails, in the present embodiment, the failure of each sector is relieved, not the failure of each radio base station.

FIG. 3 shows an image when sector 3 fails as an example. As shown in FIG. 3, a failure of sector 3 causes a failure area in which communication cannot be performed. Further, in the present embodiment, among the obstacle areas, the area where the important facility is located is referred to as an important area, and FIG. 3 also shows the important area. Specific examples of important facilities include public institutions such as hospitals, fire stations, police, and government offices. These are defined in advance by the administrator of the wireless base station.

(About reference technology)
Before explaining the configuration and operation of the radio base station control device 100 according to the embodiment of the present invention, first, a technique (referred to as a reference technique) assumed based on the prior art will be described. This reference technique will be described in order to make it easier to understand the features of the technique according to the embodiment of the present invention.

In the system of reference technology, when a radio base station fails, a communication failure that occurs in the area (failure area) covered by the radio base station (failure station) is detected by the base station (adjacent station) adjacent to the failure station. ) Relieves.

Specifically, the system according to this reference technique receives the traffic amount information processed by each adjacent station as an input, determines the control range of the antenna angle (tilt angle), and then tilts by the function of the antenna actuator or the like. Control the angle. The system of the reference technique determines whether or not the criterion for relieving the faulty station is satisfied each time the tilt angle is controlled. However, the following problems are assumed in the method related to such reference technology.

<Problem 1>
In the system of the reference technology, the final tilt angle is determined by alternately controlling the antenna angle (tilt angle) of the radio base station and observing how much the traffic before the failure occurs. do. However, in order to compare the traffic amount before and after the failure, a sufficient measurement time is required, so that it takes a long time to complete the relief. From this, problems remain from the viewpoint of emergency measures against failures.

<Problem 2>
In the system related to the reference technology, relief is provided equally at each point in the obstacle area. However, there may be important facilities within the obstacle area where relief should be prioritized. In this case, it is necessary to consider the priority for each point, but the system related to the reference technology cannot consider it.

<Problem 3>
The system of the reference technology cannot consider the case where multiple base stations fail at the same time.

<Problem 4>
In order to properly control the tilt angle of the relief station, it is necessary to estimate the radio wave propagation range corresponding to the tilt angle. As the reference technique, for example, it is conceivable to use a known technique disclosed in Non-Patent Document 1. That is, the radio wave propagation range is estimated by estimating the electric field strength. Further, the exact radio wave propagation range is calculated for a three-dimensional space of latitude, longitude, and altitude.

However, it is necessary to consider various factors such as radio wave interference and propagation loss when estimating the electric field strength, which takes a long time to calculate. Similarly, the calculation of the radio wave propagation range for the three-dimensional space requires a large amount of calculation time as compared with the calculation for the two-dimensional space. In troubleshooting, where promptness is required, the radio wave propagation range must be estimated in a short time.

Therefore, radio wave propagation range estimation using electric field strength estimation and fine-grained radio wave propagation range estimation for 3D space are not appropriate.

(Characteristics (points) of the technology according to the embodiment)
The technique according to the present embodiment can solve the above-mentioned assumed problems by providing the following features (points). The points described below are points in the technique of the embodiment, and it is not essential that the invention includes all the points. For example, it is possible to realize the technique according to the present invention without using a regional mesh.

<Point 1>
In the present embodiment, the current traffic amount and communication status are not observed each time the tilt angle is controlled, and the relief station and the tilt angle are determined only by the information defined in advance.

<Point 2>
In the present embodiment, priority is given to the area (important area) in which the important facility is located in the obstacle area, and relief is given priority from the important area.

<Point 3>
In the present embodiment, by defining the priority for the failed sector (failed sector) in all the failed stations, it is possible to deal with the case where there are a plurality of failed sectors. Then, the failed sectors can be relieved one by one in the order of priority.

<Point 4>
In this embodiment, the electric field strength estimation is not performed for the radio wave propagation range estimation. The radio wave propagation range is geometrically approximated and estimated. Further, only the range covered by the radio wave at 1.5 m above the ground (1.5 m is an example) is considered as the radio wave propagation range.

In this embodiment, in consideration of the property that "radio wave propagation loss increases according to the distance", it is assumed that radio waves reach equidistant distances over the entire range of the beam width, and under that assumption, the radio wave propagation range Is calculated using a geometrical approximation by a sector. Here, assuming a communication terminal held by the user, the height is 1.5 m above the ground as an example, but other heights may be used.

<Point 5>
In this embodiment, the area is represented by a regional mesh. The regional mesh is defined by the Administrative Administration Agency (currently the Ministry of Internal Affairs and Communications) as "a mesh in which areas are divided into meshes of almost the same size based on latitude and longitude." There are a plurality of regional meshes in the regional mesh because of the particle size of the mesh, that is, the size of the area per mesh. As an example, there are a half area mesh (one side length is about 500 m), a one eighth area mesh (one side length is about 125 m), and the like.

The coarser the mesh, the smaller the amount of calculation required for area calculation (calculation of radio wave propagation range, etc.). It is also possible to handle different meshes in a mixed manner. For example, only the important area can be represented by a fine mesh to improve the estimation accuracy of the cover area.

<Point 6>
In the present embodiment, the upper limit of the traffic capacity of the relief station is taken into consideration by setting an upper limit on the number of meshes in the radio wave propagation range of the relief station.

(Effects in the technology according to the embodiment)
The technique according to the present embodiment having the above-mentioned points produces the following effects. It should be noted that the following effects are assumed to be effects when compared with the reference technique, but are not limited to these, and are effects to be exerted on general conventional techniques.

<Effect 1>
No situational observations such as traffic volume or changes in communication conditions will be made except at the start of relief. This significantly reduces the time to complete relief compared to the reference technique.

<Effect 2>
Priority relief from important areas. This makes it more likely that critical areas will be rescued than other obstacle areas than with reference techniques.

<Effect 3>
Even if a plurality of wireless base stations fail at the same time, relief can be provided.

<Effect 4>
It is possible to estimate the radio wave propagation range in a shorter calculation time than the three-dimensional radio wave propagation range estimation using the electric field strength estimation. This reduces the accuracy of the estimation result, but the tilt angle can be determined without impairing the speed.

<Effect 5>
By changing the particle size of the regional mesh according to the number of failed sectors, the size of the fault area, etc., the time required for relief can be shortened.

<Effect 6>
Although the traffic load of the relief station increases when covering the faulty area, it is possible to prevent the relief station from becoming overloaded by the technique according to the present embodiment. Moreover, by using the number of meshes, traffic measurement or the like is not required.

Hereinafter, the configuration and operation of the radio base station control device 100 according to the present embodiment will be described in detail.

(Configuration example of wireless base station control device 100)
FIG. 4 shows a configuration diagram of the radio base station control device 100 according to the embodiment of the present invention. As shown in FIG. 4, the radio base station control device 100 includes an input reception unit 110, a data processing unit 120, and a radio base station control unit 130.

Further, as shown in FIG. 4, the data processing unit 120 has a relief priority determination unit 121, a relief station candidate selection unit 122, and a relief station / tilt angle determination unit 123. The radio base station control unit 130 has a reception unit 131 and a transmission unit 132. Further, the relief station / tilt angle determination unit 123 includes an estimation unit 123-1 that estimates the radio wave propagation range, and a determination unit 123-2 that determines a combination of the relief station and the tilt angle.

The wireless base station control device 100 may be physically one device or may be a system physically composed of a plurality of devices. For example, the "input receiving unit 110 + data processing unit 120" may be composed of one device, and the radio base station control unit 130 may be composed of one device. Further, the "input receiving unit 110 + data processing unit 120" may be referred to as a radio base station control device. The outline of the functions of each part is as follows.

<Wireless base station control unit 130>
The receiving unit 131 and the transmitting unit 132 of the radio base station control unit 130 can each communicate with the radio base station, the receiving unit 131 receives information from the radio base station, and the transmitting unit 132 sends information to the radio base station. Send.

<Input reception unit 110>
The input receiving unit 110 receives information about each radio base station, information about a failed sector (failed sector) in the failed station, failure area information, and important area information from the radio base station control unit 130. The failure area information is, for example, information indicating a failure area for each failure sector, in which communication is disabled due to a failure of the failure sector. The important area information is, for example, information indicating an important area included in the obstacle area for each obstacle area. The fault area information and the important area information may be information generated by the radio base station control unit 130 from information related to the fault sector, or may be information received from the outside.

"Information about each radio base station" includes, for example, the following information.

・ Positions (latitude, longitude), height, and orientation of all antennas installed in the radio base station ・ Vertical and horizontal beam widths of the beams of each antenna ・ Tilt angles set for each antenna ・ Adjacent Station Information In this embodiment, a radio base station located within n (km) from a certain radio base station (target radio base station) and not a malfunctioning station is set as an adjacent station to the target radio base station.

For example, the following information is included in the "information about the failed sector (failed sector) in the failed station".

・ Presence or absence of important facilities in the area covered by the failed sector ・ Size of the area covered by the failed sector ・ Number of active users communicating with the failed sector ・ Total traffic amount processed by the failed sector <Relief Priority determination unit 121>
The relief priority determination unit 121 receives information from the input reception unit 110 and determines the relief priority of the failure sector based on the nature of the failure sector. In the present embodiment, relief is performed one by one from the failed sector having the highest relief priority.

<Relief Bureau Candidate Selection Department 122>
The relief station candidate selection unit 122 selects one or more relief station candidates from one or more adjacent stations to the failure station to which the failure sector belongs.

<Relief Bureau / Tilt Angle Determination Unit 123>
The relief station / tilt angle determination unit 123 determines the relief station and its tilt angle that can most effectively perform relief from one or more relief station candidates and tilt angles selected by the relief station candidate selection unit 122. ..

(Operation of wireless base station control device 100)
Hereinafter, an operation example of the radio base station control device 100 having the above configuration will be described in detail according to the procedure of the flowchart of FIG.

<S1>
In S1, the receiving unit 131 of the radio base station control unit 130 collects information necessary for carrying out the relief from the radio base station or the like, and the input receiving unit 110 receives the information from the receiving unit 131. The content of the received information is as described above. The information received by the input receiving unit 110 is passed to the data processing unit 120.

<S2, S3>
When a plurality of failed sectors exist, the radio base station control device 100 provides relief one by one from the failed sector having the highest relief priority.

Therefore, in S2, the relief priority determination unit 121 confirms whether or not an unrelieved failed sector exists, and ends the process if it does not exist. If there is an unrelieved failed sector, the process proceeds to S3, and the rescue priority determination unit 121 determines the rescue priority of each unrelieved failed sector, and among the unrelieved failed sectors, the fault with the highest rescue priority. Select one sector.

The method by which the relief priority determination unit 121 determines the relief priority of each failure sector is not limited to a specific method, but for example, "presence or absence of important facilities in the area covered by the failure sector", "the failure sector is Relief based on indicators according to the urgency of communication establishment such as "size of area covered", "number of active users communicating with failed sector", "total traffic amount processed by failed sector" Priority can be determined. Specific indicators may be appropriately determined by the system operator.

For example, when the relief priority determination unit 121 determines the relief priority based on the "number of active users communicating with the failed sector", the larger the number of active users, the higher the relief priority is set. The relief priority determination unit 121 determines the relief priority as "presence or absence of important facilities in the area covered by the failed sector", "size of the area covered by the failed sector", and "communication with the failed sector". It may be determined by using any one of "the number of active users who have been active" and "the total traffic amount processed by the failed sector", or it may be determined by using any one or more of them.

<S4 to S7>
In S4 to S7, the relief station candidate selection unit 122 selects a relief station candidate for the failed sector determined in S3 from one or more adjacent stations of the failed sector.

Specifically, in S4, the relief station candidate selection unit 122 determines whether or not there is an unrelieved important area in the failed sector, and if it exists, the relief priority area is set as an important area (S5) and exists. If not, the relief priority area is set as an obstacle area (an obstacle area that is not an important area) (S6). In addition, both the obstacle area and the important area here are areas excluding the area where the coverage by the relief bureau has been decided by the processing so far. The unrelieved important area is an important area where the coverage rate does not reach the threshold value.

In S7, the relief station candidate selection unit 122 selects one or more relief station candidates from the vicinity of the relief priority area (important area or obstacle area not including the important area). The more specific selection process is as follows.

As described above, the relief station candidate selection unit 122 selects a relief station candidate from one or more adjacent stations to the failed sector to be rescued.

More specifically, the relief station candidate selection unit 122 selects m radio base stations near the center of gravity of the faulty area as candidates for the relief station among one or more adjacent stations. m is an integer of 1 or more and is a predetermined number. However, if an important area exists in the obstacle area, m base stations near the center of gravity of the important area are selected as candidates for the relief station instead of the center of gravity of the obstacle area.

If the number l of adjacent stations is l <m, the candidates for the relief station are all adjacent stations to the failed sector.

<S8>
In S8, the relief station / tilt angle determination unit 123 estimates the radio wave propagation range for each combination of tilt angles of the candidates of each relief station. Since these radio wave propagation range estimates can be calculated independently for each combination, parallel calculation is possible. This makes it possible to speed up the calculation in S8. Since the calculation time of S8 generally occupies most of the execution time in this system, this speeding up greatly contributes to shortening the time until relief.

The relief station antenna has a tilt angle settable range. In the present embodiment, the tilt angle is changed within a configurable range with a particle size of a predetermined angle unit such as 0.5 ° unit or 1.0 ° unit. The tilt angle prepared for each predetermined angle unit within the settable range is called "each tilt angle". Then, the radio wave propagation range is estimated independently for all the combinations of the antenna of each relief station and the "tilt angle" of each antenna.

For example, when the settable range of the tilt angle of the antenna of a certain relief station is 1 ° to 15 ° and the predetermined angle unit is 1 °, the antenna of the relief station is {1 °, 2 ° ,. ..... For each of the 15 tilt angles of 14 ° and 15 °}, the radio wave propagation range is estimated by the method described later.

In the present embodiment, for the sake of convenience, it is described that the relief station has one antenna. However, if the relief station has a plurality of antennas, processing may be performed for each relief station candidate antenna. Often, the processing content is the same as the processing described below.

Generally, the exact radio wave propagation range is calculated in three dimensions: latitude, longitude, and altitude. However, it is necessary to estimate the radio wave propagation range in a shorter time in order to realize the quickness of relief. Therefore, in the present embodiment, only the range covered by the radio wave at 1.5 m above the ground is considered as the radio wave propagation range. Here, assuming a communication terminal held by the user, the height is 1.5 m above the ground as an example, but a height other than 1.5 m may be used.

As a result, the accuracy of the estimation result is reduced because the radio wave propagation range is not estimated three-dimensionally, but it can be expected that the performance will be improved from the viewpoint of calculation speed.

Further, the relief station / tilt angle determination unit 123 according to the present embodiment calculates the radio wave propagation range using a geometric approximation by a fan shape.

In order to obtain the radio wave propagation range strictly, it is common to estimate the electric field strength for each point and use this estimation result. However, as described above, in order to prioritize the speed of relief, it is necessary to estimate the radio wave propagation range in a shorter time. Therefore, in the present embodiment, as described above, in consideration of the property that "the propagation loss of the radio wave increases according to the distance", it is assumed that the radio wave reaches an equidistant distance over the entire range of the beam width, and this assumption is made. Below, the radio wave propagation range is calculated using a geometrical approximation by a sector. The specific calculation method is as follows.

Here, the position of the antenna of the radio base station (candidate for rescue station) is (latitude lat, longitude lon), the height of the antenna is h, the central direction of the antenna is az _center, and the tilt angle of the antenna is set. Let x be, and let α and β be the vertical and horizontal beam widths (°) of the antenna beam of the antenna, respectively. The height h of the antenna is the height from 1.5 m above the ground.

Further, regarding the settable range of the tilt angle x, the minimum value is x _min and the maximum value is x _max .

At this time, the range of the angle of the antenna beam in the vertical direction is [ _vmin , _vmax ]. v _min and v _max are obtained by the following equations, respectively.

v _min = max {x-α / 2, x _min }, v _max = min {x + α / 2, x _max }
Assuming that the radii of the two sectors used for approximating the radio wave propagation range are d _min and d _max , they can be obtained by the following equations, respectively.

d _min = h / tan (v _max ), d _max = h / tan (v _min )
_{The d min} and d _max obtained by the above formula are shown in FIG. 6 as an illustration.

Assuming that the start azimuths of the above two sectors are az _start and the end azimuths are az _end , these can be obtained by the following equations.

az _start = az _center + β / 2, az _end = az _center -β / 2
As mentioned above, the start azimuth and end azimuth of the two sectors are the same. _{_However, az} _start, az _end of domain a 0 ≦ _az _start, and _az end <360 °. According to the above formula, when _{the calculated values of az start} and az _end are out of the definition range, the remainder obtained by the method of 360 is used.

Center point (lat, lon), radius _{d min,} a central angle at _az start _{-az _end,} the sector facing the direction of _{az end The} from _{az start} and sector A. Similarly, center point (lat, lon), radius _{d max,} central angle in _az start _{-az end _The,} the sector facing the direction of _{az end The} from _{az start} and sector B.

The relief station / tilt angle determination unit 123 obtains the sector A and the sector B by the above calculation, and among the areas included in the sector B, the area not included in the sector A is used as the estimation result of the radio wave propagation range. FIG. 7 shows an illustration of the sector A and the sector B. FIG. 7 is a top view of two sectors.

The relief station / tilt angle determination unit 123 performs the above calculation for each relief station candidate and each tilt angle to estimate the radio wave propagation range.

<S9, S10>
In S9, the relief station / tilt angle determination unit 123 adopts the combination of the relief station candidate and the tilt angle, which will be described later, with the highest coverage rate and the tilt angle thereof.

In S10, the relief station / tilt angle determination unit 123 transmits the adopted control content to the radio base station control unit 130. For example, when the relief station A is adopted as the relief station and γ is adopted as the tilt angle, the relief station / tilt angle determination unit 123 sets the tilt angle of the relief station A to γ with respect to the radio base station control unit 130. Send control information about what you want to do. In response to this, the transmission unit 132 of the radio base station control unit 130 transmits an instruction to the relief station A to set the tilt angle of the antenna to γ. Hereinafter, the processing content of S9 will be described in more detail.

<Overview of S9 processing>
The relief station / tilt angle determination unit 123 in the present embodiment calculates the coverage rate using the estimation result of the radio wave propagation range calculated in S8, and determines the relief station and its tilt angle based on the calculated coverage rate. do.

The coverage rate is the ratio of covering the obstacle area with the radio wave propagation range (cover area), and more specifically, it is called the obstacle area coverage rate. However, if there is an important area in the obstacle area, the important area coverage rate is also defined.

When the important area coverage rate is defined, the relief station / tilt angle determination unit 123 adopts the "relief station / tilt angle combination" having the highest important area coverage rate.

If the important area coverage rate is not defined (when there is no important area in the obstacle area), the "relief station / tilt angle combination" with the highest obstacle area coverage rate is adopted.

However, there are restrictions on the number of meshes in the area for the combination of the relief station and the tilt angle. Specifically, the number of meshes in the radio wave propagation range calculated in S8 is calculated, and the "relief station / tilt angle combination" in which this exceeds the threshold value is not adopted. However, such restrictions may not be provided.

<Details of S9 processing: Calculation method of fault area coverage rate>
Next, as details of the processing of S9, a method of calculating the fault area coverage rate will be described.

Here, the radio wave propagation range calculated in S8 is defined as the cover area. In addition, the area originally covered by the Relief Administration candidate is defined as the foot area. It is very good to acquire the foot area as base station information, or the relief station / tilt angle determination unit 123 may estimate the foot area by using the radio wave propagation range estimation method described above. The area that combines the obstacle area and the foot area is defined as the relief target obstacle area.

The relief station / tilt angle determination unit 123 compares the cover area and the relief target obstacle area, calculates the ratio included in the cover area in the relief target obstacle area, and uses this as the obstacle area coverage rate.

Regarding the calculation of the coverage rate by the relief station / tilt angle determination unit 123, in this embodiment, it is calculated using the number of meshes of the regional mesh.

Here, as described above, the regional mesh is "a mesh in which the area is divided into meshes of almost the same size based on latitude and longitude". More specifically, the regional mesh is "a mesh in which the area is divided into meshes of almost the same size based on latitude and longitude" defined by the administrative agency (currently the Ministry of Internal Affairs and Communications).

There are multiple regional meshes in the regional mesh because of the particle size of the mesh, that is, the size of the area per mesh. For example, there are a half area mesh (one side length is about 500 m), a one eighth area mesh (one side length is about 125 m), and the like.

The coarser the mesh, the smaller the amount of calculation required to calculate the cover area, and the time required to estimate the cover area can be shortened. In addition, the effect of changing the particle size of the regional mesh is closed to the function of calculating the coverage rate, and it is possible to change the particle size of the regional mesh without affecting other functional parts. The particle size of the regional mesh can be appropriately determined by the operator of the radio base station control device according to the present embodiment.

Assuming that the area included in the relief target obstacle area among the coverage areas is a relief area, when the area mesh is used as described above, the relief station / tilt angle determination unit 123 uses the following formula to cover the obstacle area. Is calculated.

(Disability area coverage rate) = (Number of meshes in relieved obstacle area) / (Number of meshes in relief target obstacle area)
<Details of S9 processing: Calculation method of important area coverage rate>
Subsequently, as details of the processing of S9, a method of calculating the important area coverage rate will be described.

If there is an important area in the obstacle area, the area that combines the important area and the foot area is defined as the important area to be rescued.

The relief station / tilt angle determination unit 123 compares the cover area with the important area to be rescued, calculates the ratio of the important area to be rescued to be included in the cover area, and uses this as the important area coverage rate.

That is, assuming that the area included in the important area to be rescued is the important area that can be rescued, the relief station / tilt angle determination unit 123 is important in the following formula when the area mesh is used as described above. Calculate the area coverage rate.

(Important area coverage rate) = (Number of meshes in important areas that can be rescued) / (Number of meshes in important areas to be rescued)
<S11, S12>
In S11 and S12, the relief station / tilt angle determination unit 123 determines whether or not to end the relief of the target failed sector (the failed sector selected in S3). That is, the relief station / tilt angle determination unit 123 determines whether or not the relief end condition is satisfied, and if so, ends the relief of the failed sector currently targeted for relief, and returns to S2. If the termination condition is not met, the area returned to S4 for the obstacle area and the important area excluding the area covered by the relief station, and further relief is provided.

The relief end condition is not limited to a specific condition, but for example, "the relief station / tilt angle control so far satisfies the important area coverage rate P% or more and the failure area coverage rate Q% or more of the failed sector". .. Further, feedback such as the traffic amount and the cover area due to the control of the tilt angle in S10 may be obtained, and the tilt angle may be adjusted in consideration of this.

The flow of FIG. 5 shows the processing using the threshold values such as P and Q described above as the relief end condition. In S11, the relief station / tilt angle determination unit 123 has the failure area coverage rate and the important area coverage rate. To update. In S12, the relief station / tilt angle determination unit 123 determines whether or not the obstacle area coverage rate and the important area coverage rate are each equal to or higher than the threshold value. Return to.

(Hardware configuration example)
The radio base station control device 100 according to the present embodiment can be realized by, for example, causing a computer to execute a program describing the processing contents described in the present embodiment. The "computer" may be a physical machine or a virtual machine on the cloud. When using a virtual machine, the "hardware" described here is virtual hardware.

The above program can be recorded on a computer-readable recording medium (portable memory, etc.), saved, and distributed. It is also possible to provide the above program through a network such as the Internet or e-mail.

FIG. 8 is a diagram showing an example of the hardware configuration of the above computer. The computer of FIG. 8 has a drive device 1000, an auxiliary storage device 1002, a memory device 1003, a CPU 1004, an interface device 1005, a display device 1006, an input device 1007, an output device 1008, and the like, which are connected to each other by a bus BS, respectively.

The program that realizes the processing on the computer is provided by, for example, a recording medium 1001 such as a CD-ROM or a memory card. When the recording medium 1001 storing the program is set in the drive device 1000, the program is installed in the auxiliary storage device 1002 from the recording medium 1001 via the drive device 1000. However, the program does not necessarily have to be installed from the recording medium 1001, and may be downloaded from another computer via the network. The auxiliary storage device 1002 stores the installed program and also stores necessary files, data, and the like.

The memory device 1003 reads and stores the program from the auxiliary storage device 1002 when there is an instruction to start the program. The CPU 1004 realizes the function related to the radio base station control device 100 according to the program stored in the memory device 1003. The interface device 1005 is used as an interface for connecting to a network. The display device 1006 displays a GUI (Graphical User Interface) or the like by a program. The input device 1007 is composed of a keyboard, a mouse, buttons, a touch panel, and the like, and is used for inputting various operation instructions. The output device 1008 outputs the calculation result.

(Summary of embodiments)
This specification describes at least the radio base station control device, the communication remedy method, and the program described in each of the following sections.
(Section 1)
A relief station that relieves communication in a faulty area that occurs when a radio base station fails, and a radio base station control device that determines its tilt angle.
An estimation unit that estimates the radio wave propagation range without estimating the electric field strength for each tilt angle of each relief station candidate in multiple relief station candidates.
From a plurality of combinations of relief station candidates and tilt angles, a combination of a specific relief station candidate and tilt angle is used as the relief station and its tilt angle based on the ratio of the area covered by the radio wave propagation range in the obstacle area. A radio base station controller with a decision-making unit.
(Section 2)
When the obstacle area includes an important area including an important facility, the estimation unit and the determination unit determine the relief station and its tilt angle for the important area in preference to the obstacle area which is not the important area. The radio base station control device according to paragraph 1.
(Section 3)
The radio according to item 1 or 2, wherein the estimation unit estimates a fan-shaped range at a predetermined height assuming that the communication terminal used by the user is at a predetermined height as the radio wave propagation range. Base station controller.
(Section 4)
The radio base station control device according to any one of the items 1 to 3, wherein the determination unit calculates the ratio by expressing the area by a regional mesh.
(Section 5)
The radio base station control device according to item 4, wherein the determination unit does not select a combination of a relief station candidate and a tilt angle whose number of meshes in the radio wave propagation range exceeds the upper limit as the relief station and its tilt angle.
(Section 6)
Each radio base station has one or more sectors, and the target of relief is from one or more failed sectors in one or more failed radio base stations in descending order of relief priority determined according to the urgency of communication establishment. The radio base station control device according to any one of paragraphs 1 to 5, further comprising a relief priority determination unit for selecting a faulty sector.
(Section 7)
It is a communication relief method executed by a relief station that rescues communication in a faulty area that occurs when a radio base station fails and a radio base station control device that determines the tilt angle thereof.
A step of estimating the radio wave propagation range without estimating the electric field strength for each tilt angle of each relief station candidate in a plurality of relief station candidates.
From a plurality of combinations of relief station candidates and tilt angles, a combination of a specific relief station candidate and tilt angle is used as the relief station and its tilt angle based on the ratio of the area covered by the radio wave propagation range in the obstacle area. Steps to decide and
Communication remedy method.
(Section 8)
A program for making a computer function as each part in the radio base station control device according to any one of the items 1 to 6.

Although the present embodiment has been described above, the present invention is not limited to such a specific embodiment, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. It is possible.

10 Radio base station 100 Radio base station control device 110 Input reception unit 120 Data processing unit 121 Relief priority determination unit 122 Relief station candidate selection unit 123 Relief station / tilt angle determination unit 123-1 Estimating unit 123-2 Determining unit 130 Wireless Base station control unit 131 Receiver unit 132 Transmitter unit 1000 Drive device 1001 Recording medium 1002 Auxiliary storage device 1003 Memory device 1004 CPU
1005 Interface device 1006 Display device 1007 Input device 1008 Output device

Claims

A relief station that relieves communication in a faulty area that occurs when a radio base station fails, and a radio base station control device that determines its tilt angle.
An estimation unit that estimates the radio wave propagation range without estimating the electric field strength for each tilt angle of each relief station candidate in multiple relief station candidates.
From a plurality of combinations of relief station candidates and tilt angles, a combination of a specific relief station candidate and tilt angle is used as the relief station and its tilt angle based on the ratio of the area covered by the radio wave propagation range in the obstacle area. A radio base station controller with a decision-making unit.
When the obstacle area includes an important area including an important facility, the estimation unit and the determination unit determine the relief station and its tilt angle for the important area in preference to the obstacle area which is not the important area. The radio base station control device according to claim 1.
The radio base station according to claim 1 or 2, wherein the estimation unit estimates a fan-shaped range at a predetermined height assuming that the communication terminal used by the user is at a predetermined height as the radio wave propagation range. Control device.
The radio base station control device according to any one of claims 1 to 3, wherein the determination unit calculates the ratio by expressing the area by a regional mesh.
The radio base station control device according to claim 4, wherein the determination unit does not select a combination of a relief station candidate and a tilt angle whose number of meshes in the radio wave propagation range exceeds the upper limit as the relief station and its tilt angle.
Each radio base station has one or more sectors, and the target of relief is from one or more failed sectors in one or more failed radio base stations in descending order of relief priority determined according to the urgency of communication establishment. The radio base station control device according to any one of claims 1 to 5, further comprising a relief priority determination unit for selecting a faulty sector.
It is a communication relief method executed by a relief station that rescues communication in a faulty area that occurs when a radio base station fails and a radio base station control device that determines the tilt angle thereof.
A step of estimating the radio wave propagation range without estimating the electric field strength for each tilt angle of each relief station candidate in a plurality of relief station candidates.
From a plurality of combinations of relief station candidates and tilt angles, a combination of a specific relief station candidate and tilt angle is used as the relief station and its tilt angle based on the ratio of the area covered by the radio wave propagation range in the obstacle area. Steps to decide and
Communication remedy method.
A program for making a computer function as each part in the radio base station control device according to any one of claims 1 to 6.