JP2993551B2 - Zone change system in mobile communication - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zone change system for controlling the size of a zone formed by a base station in mobile communication.

[0002]

2. Description of the Related Art In mobile communication, a zone covered by one base station, that is, a communication range between one base station and a mobile station is called a zone. This zone is also called a cell. This zone is determined by the directivity of the antenna of the base station and the like.

FIG. 1 is a diagram illustrating zones formed by base stations. In FIG. 1, 1 is a base station, 2 is a power divider, 3 is an antenna, 4 and 5 are zones. Also R
₁ is the distance from base station 1 to the end of the zone 5 zone, R ₂
Represents the distance from the base station 1 to the end of the zone 4 zone.
The transmission power is supplied from the transmitter to the antenna 3 from the power distributor 2.

The zones 4 and 5 of the base station 1 are determined by the angles α ₁ and α ₂ indicating the directivity in the vertical plane of the antenna 3. When directivity angle alpha _1, the communication range of the zone 5 is the base station 1, the directivity when the angle alpha _2, the zone 4 is a communication range of the base station 1.

When the base station 1 forms the zone 4, the antenna 3 of the base station 1 sets an angle α ₂ indicating directivity in a vertical plane such that the distance of R ₂ from the base station 1 is the zone end. . Next, when it is necessary to narrow the zone formed by the base station 1 to the range shown in the zone 5, the directivity of the antenna 3 of the base station 1 in the vertical plane is changed to the angle α ₂ and the base station 1 distance R ₁ is made to be zone end from.

[0006] Conventionally, when a base station is added in mobile communication, the zone of an existing base station has been changed. This is to prevent interference of radio waves between base stations using the same frequency and to use the frequency effectively.

FIG. 2 is a diagram for explaining a case where base stations are added. In FIG. 2, the zone is changed by two base stations A and B as shown on the left side. In this case, the point a, and directivity of the vertical plane of the antenna of the base station as the base station B to point the zone end distance R _B from the base station B of the distance R _A from the base station A base station A Is set. In order to cope with an increase in the number of mobile stations in the zone formed by the base stations A and B, it is necessary to newly install a base station C as shown on the right side of FIG. In the base stations A and B, in order to prevent radio wave interference with other base stations using the same frequency as the base station A and the base station B and to effectively use the frequency, the distances R _A ′ and R The directivity in the vertical plane of the antenna of the base station must be changed so that _B 'is the end of each zone.

FIG. 3 is a block diagram showing a configuration for forming directivity in a vertical plane of a conventional antenna. In FIG. 3, 3-1 is an array antenna, 6 is a feed point for connecting a transceiver installed in a base station, 7 is a power distributor, 8, 9, and 1
0 and 11 are feed lines connecting the power distributor 7 and the antenna 3, and 12, 13, 14 and 15 are array antennas 3
-1, a feed point 16 is an antenna element arranged in an array inside the array antenna 3-1;
8 represents directivity in the vertical plane of the antenna. Φ is the phase of the transmission signal fed to the feed point 6, φ-φ ₁ is the phase of the transmission signal fed to the feed point 12 of the array antenna 3-1, and φ-φ ₂ is the phase of the array antenna 3-1. The phase of the transmission signal fed to the feeding point 13, φ−φ ₃ is the array antenna 3
−1, the phase of the transmission signal fed to the feeding point 14, φ−φ
₄ is the phase of the transmission signal fed to the feed point 15 of the array antenna 3-1, θ ₁ is the angle of the antenna directivity 17 from the antenna horizontal direction, and θ ₂ is the angle of the antenna directivity 18 from the antenna horizontal direction. Represent.

The transmission signal fed to the feeding point 6 in FIG.
The distributed transmission signals distributed by the power distributor 7 are supplied to feed points 12, 13, 14 and 1 of the array antenna 3-1 via feed lines 8, 9, 10 and 11, respectively.
5 is supplied. At this time, the feed lines 8, 9, 10, and 1
1 to make the feed points 12,
The transmission signals fed to 13, 14, and 15 are fed to feed point 6
Φ-φ for the phase φ of the transmission signal fed to
_The power is supplied with the phase changed by ₁ , φ−φ ₂ , φ−φ ₃ , and φ−φ ₄ . Feeding point 1 inside array antenna 3-1
The transmission signals fed from 2, 13, 14 and 15 are:
The radiation is radiated from the antenna elements 16 arranged in an array inside the array antenna 3-1. The directivity of the array antenna is determined by the phase of a transmission signal fed to the antenna elements forming the array antenna. By changing this phase difference, the directivity in the vertical plane of the antenna can be changed as indicated by directivities 17 and 18.

The directivity in the vertical plane of the antenna 3 is determined by changing the amount of delay caused by the feed lines 8, 9, 10 and 11 so that the phase of the transmission signal fed to the feed points 12, 13, 14 and 15 is changed. Can be changed. Therefore, when changing the directivity, the feed lines 8, 9,
The directivity in the vertical plane of the antenna has been changed by replacing 10 and 11 with feeders that cause a corresponding delay.

[0011]

In the base station, FIG.
In the method of defining the zone of the base station using the array antenna shown in (1), it is necessary to replace the feeder lines 8, 9, 10 and 11 to which the antenna 3 is connected each time the base station is expanded as shown in FIG. Occurs. In these operations, it is necessary to perform outdoor work to replace the feed line of the antenna, and the work may be dangerous due to weather or work environment, or the service may be interrupted when the feed line is replaced. There was a point.

When the number of mobile stations existing in a zone formed by one of the two adjacent base stations increases, all the frequencies allocated to the base station are used up, and the frequency of the base station is exhausted. Occurs. At that time, there is a case where there is a margin in the frequency allocated to the adjacent base station. In this case, if the directivity of the vertical plane of the antenna of the base station can be changed quickly, the zone can be changed dynamically, so that the base station can dynamically change the frequency used by these mobile stations. Can be distributed, and communication with the mobile station can be ensured. This is because the base station with increased mobile stations changes the directivity in the vertical plane of the antenna to reduce the zone formed by the base station, and the adjacent base station changes the directivity in the vertical plane of the antenna. This can be realized by performing an operation of enlarging a zone formed by adjacent base stations.

However, since the antenna shown in FIG. 3 is used, in order to change the directivity in the vertical plane of the antenna, it is necessary to replace the feed line connected to the antenna of the corresponding base station. is there. For this reason, there has been a problem that it is not possible to promptly respond to these situations at any time.

An object of the present invention is to make it possible to arbitrarily change the size of a zone formed by a base station by adopting a configuration in which the directivity of an antenna of a base station can be quickly changed in mobile communication. Is to do so.

[0015]

In order to achieve the above object, the invention according to claim 1 is a system for changing a zone in which a base station communicates with a mobile station in mobile communication, comprising: an antenna; A base station having directivity changing means capable of changing the directivity of the antenna in a vertical plane; and controlling the directivity changing means of the base station to change the directivity of the antenna in a vertical plane. And a control device for changing the zone of the base station by causing the control device to change the zone of the base station, wherein the control device is installed outside the base station.

According to a second aspect of the present invention, there is provided a system for changing a zone in which a base station communicates with a mobile station in a mobile communication, wherein an antenna and a directivity in a vertical plane of the antenna are changed. A plurality of base stations having a possible directivity changing means, and a plurality of base stations having a directivity changing means for controlling the directivity changing means of the plurality of base stations at a time, and changing the directivity in a vertical plane of the antenna to obtain the plurality of base stations. And a control device for changing the zone of the station.

The invention according to claim 3 is the zone change system according to claim 2, wherein the control device changes zones of the plurality of base stations in consideration of traffic of the plurality of base stations. It is characterized by doing.

The invention according to claim 4 is the invention according to claims 1 to 3
Wherein the antenna is an array antenna, and the directivity changing means changes the phase of a transmission signal supplied to the array antenna to change the directivity in a vertical plane of the antenna. It is characterized by changing sex.

[0019]

In mobile communication, a base station is provided with a directivity changing means capable of arbitrarily changing the directivity of the antenna in a vertical plane and a control device for controlling the directivity changing means. Can easily change the size of the zone that can communicate with the mobile station when necessary.

Further, by controlling the zones of a plurality of base stations collectively, when a large number of calls are generated, it is possible to dynamically control the zone setting according to the generation of the calls.

[0021]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 4 is a block diagram showing a configuration of an embodiment of the present invention. FIG. 5 is an embodiment of an antenna capable of arbitrarily changing the directivity in a vertical plane used in the present invention. FIG. 3 is a block diagram showing the configuration of FIG.

In FIG. 4, 1 is a base station, 3 is an antenna, 19 is a directivity changing circuit for changing the directivity in the vertical plane of the antenna 3, 29 is a control device for controlling the directivity changing circuit 19, 4 and Reference numeral 5 denotes a zone formed by the base station 1. R ₁ represents the distance from the base station 1 to the end of the zone 5 zone, and R ₂ represents the distance from the base station 1 to the end of the zone 4 zone.

In FIG. 4, when the base station 1 forms a zone 4 and provides a mobile communication service, the distance from the base station 1 to the end of the area of the zone 4 where the radio wave radiated from the antenna 3 is formed. Is R ₁ . When the zone formed by the base station 1 is changed from the base station 1 to the zone 5 having the distance R ₂ as the area end, the directivity changing circuit 19 is operated under the control of the control device 29 to operate the antenna 3 in the vertical plane. Can be realized by changing the directivity.

If the control device 29 is installed inside the base station 1, for example, indoors, the zone can be easily changed regardless of the weather or the installation location of the antenna 3. Furthermore, by extending the control line and installing the control devices of a plurality of base stations outside the base station, the zones of the plurality of base stations can be changed at one place.

FIG. 5 shows the configuration of the directivity changing circuit 19 and how the control device 29 changes the directivity of the antenna 3 to control the zone of the base station with reference to FIG. Will be explained.

In FIG. 5, 3-1 is an array antenna,
Reference numeral 16 denotes an antenna element arranged in an array inside the array antenna 3-1, and reference numeral 19 denotes a directivity changing circuit that changes the directivity of the antenna 3 in a vertical plane. 24, 25, 2
Reference numerals 6 and 27 denote variable phase shifters installed inside the directivity changing circuit 19 for changing the phase, and 29 denotes variable phase shifters 24 and 2.
A control device for controlling 5, 26 and 27 is a control line connecting the variable phase shifters 24, 25, 26 and 27 and a control device 29. Reference numeral 37 denotes a power distributor installed inside the directivity changing circuit 19, 20, 21, 22, and 23 denote feed lines connecting the directivity changing circuit 19 and the array antenna 3-1, and 12, 13, 14, and 15 denote power supply lines. Array antenna 3-
1 is a feeding point, 16 is an antenna element constituting the array antenna 3-1, and 17 and 18 represent directivity in a vertical plane of the antenna. Φ is the phase of the transmission signal fed to the feeding point 6, φ−φ ₁ is the phase of the transmission signal fed to the feeding point 12 of the antenna, and φ−φ ₂ is the feeding point 1 of the antenna.
3, the phase of the transmission signal supplied to the power supply point 13, φ-φ ₃ is the phase of the transmission signal supplied to the power supply point 14 of the antenna, φ-φ ₄ is the phase of the transmission signal supplied to the power supply point 15 of the antenna, θ ₁
Is the angle of the antenna directivity 17 from the horizontal direction of the antenna,
theta ₂ represents an angle from the antenna horizontal radiation pattern 18.

Now, the feeding point 1 of the array antenna 3-1
The phases of the transmission signals fed to 2, 13, 14 and 15 are compared with the phase φ of the transmission signal fed to feeding point 6 by φ−φ ₁ , φ−φ ₂ , φ−φ ₃ and φ− it is possible to change the phase in the variable phase shifter 24, 25, 26, and 27 such that the phi _4. The change in the phase of the transmission signal controls the directivity of the antenna. At this time, the delay due to the feed line is taken into account.

The degree to which each variable shifter shifts the phase of the transmission signal supplied to the antenna element is determined by the control unit 29.
To control. The directivity of the radio wave radiated to the theta ₁ from the array antenna 3-1, a variable phase shifter 24 and 25,
Each phase amount set to 26 and 27, array antenna 3
The phase amounts and the like set in the variable phase shifters 24, 25, 26 and 27 for obtaining the directivity of the radio wave radiated from −1 into θ ₂ are stored in the control device 29. Control device 29
When the directivity of the antenna is input, the control device 29 selects each phase amount to be set in the variable phase shifters 24, 25, 26 and 27 corresponding to the input directivity, and selects the phase of the transmission signal supplied to the antenna. And a desired directivity can be obtained.

According to the configuration of the present invention, it is possible to change the directivity in the vertical plane of the antenna, that is, the size of the zone while the service is continued.

The controller 29 includes variable phase shifters 24, 25,
The sets of the phase amounts to be set in the phase shifters 24 and 2 are stored and stored.
It is also possible to adopt a configuration in which the respective phase amounts set in 5, 26 and 27 are obtained by calculation. In this case, the control device 29
Can continuously change the phases of the variable phase shifters 24, 25, 26 and 27.

FIG. 6 is a diagram for explaining the collective control of zones of a plurality of base stations.

In FIG. 6, 30 and 33 are base stations A
Are changed by the base station C, 31 and 34 are changed by the base station C, 32 and 35 are changed by the base station B, and 36 is a control device for collectively managing and controlling the antenna directivity of each base station. It is.

FIG. 6 shows a plurality of base stations adjacent to each other.
It is shown that a directivity changing circuit having the configuration shown in FIG. 4 is installed, and a zone of a plurality of base stations is centrally managed by a control device that collectively manages these controls.

In FIG. 6, base station A defines zone 30 as
The base station C changes the zone 31 and the base station B changes the zone 35 to provide a mobile communication service. At this time, many calls occur at the base station A and the base station B, and the frequencies allocated to the base station A and the base station B become insufficient,
A state occurs where the frequency assigned to the base station C has room. At this time, the control device 36 changes the zone to the relatively small zone 33 with respect to the base station B, changes the zone to the relatively small zone 35 with respect to the base station B,
Control for changing the directivity in the vertical plane of the antenna of each base station is collectively performed so as to change to the zone 34 relatively large for the base station C. As a result, the zone of the base station A and the base station B is reduced, and the zone of the base station C is increased.
A part of the mobile station that has communicated with the base station C will communicate with the base station C. In this manner, the traffic of the base station A and the base station B can be distributed to the base station C. This change can be made while each of the base stations A, B, and C continues the service.

Further, in the zone change system of the present invention, since the zone of the base station C becomes large, there is a problem of radio wave interference with another base station using the same frequency as the frequency assigned to the base station C. It is possible that this will occur. However, such a situation indicates that the base station C
Can be avoided by allocating frequencies so that radio wave interference does not occur even in the state changed to. As a result, if the minimum necessary frequency is allocated to each base station, a service can be provided, and the frequency can be effectively used.

As described above, according to the present invention, the size of the zone can be easily controlled by controlling the directivity changing circuit in the base station and changing the directivity in the vertical plane of the antenna. It becomes possible. Furthermore, since there is no need to replace the power supply line, the size of the zone can be changed without being affected by the weather or the installation location of the antenna.

Further, by using a control device that integrally manages a plurality of base stations, it becomes possible to distribute traffic concentrated on a certain base station.

In the description of this embodiment, the directivity changing circuit for electrically changing the directivity in the vertical plane of the antenna for changing the zone of the base station has been described. However, the present invention is not limited to using such a directivity changing circuit. For example, a directivity changing circuit that changes the directivity of the antenna in the vertical direction by mechanically tilting the mounting angle of the antenna can be used. In this case, the size of the zone can be changed by controlling the directivity changing circuit that changes the mounting angle.

[0040]

According to the present invention, in the base station, the size of the zone is controlled by controlling the directivity changing circuit.
By easily changing the directivity in the vertical plane of the antenna, it is possible to easily control the antenna. Furthermore, since there is no need to replace the power supply line, the size of the zone can be changed without being affected by the weather or the installation location of the antenna.

Further, by using a control device for integrally managing a plurality of base stations, it becomes possible to distribute traffic concentrated on a certain base station.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a zone formed by a base station.

FIG. 2 is a diagram illustrating a case where a base station is added.

FIG. 3 is a block diagram showing a configuration for forming directivity in a vertical plane of a conventional antenna.

FIG. 4 is a block diagram showing a configuration of one embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of an embodiment of an antenna used in the present invention and capable of arbitrarily changing directivity in a vertical plane.

FIG. 6 is a diagram illustrating collectively controlling zones of a plurality of base stations according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Base station 2,7,37 Power divider 3 Antenna 3-1 Array antenna 4,5,30,31,32,33,34,35 Zone 6 Feeding point for connecting a transmitter 8,9,10,11 Wires 12, 13, 14, 15 Feeding point of array antenna 16 Antenna element 17, 18 Directivity of antenna in vertical plane 19 Directivity changing circuit 20, 21, 22, 23 Power supply for connecting directivity changing circuit and array antenna Wire 28 Control line 29 Control device 36 Control device for collectively managing a plurality of base stations φ, φ-φ ₁ , φ-φ ₂ , φ-φ ₃ , φ-φ ₄ Transmission signal phase θ ₁ , θ ₂ Vertical of antenna ₂ angle R ₁ from directivity of the antenna horizontal _{plane, R 2, R a, R} a ', R B, R B' distance to the zone edge from the base station

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H04B 7/24-7/26 102 H04Q 7/00-7/38

Claims (4)

(57) [Claims] 1. A system for changing a zone in which a base station communicates with a mobile station in mobile communication, comprising: an antenna; and a directivity changing means capable of changing the directivity of the antenna in a vertical plane. And a control device for controlling directivity changing means of the base station, and changing a zone of the base station by changing directivity in a vertical plane of the antenna, the control device comprising: Is a zone change system installed outside the base station. 2. A system for changing a zone in which a base station communicates with a mobile station in mobile communication, comprising: an antenna; and a directivity changing means capable of changing the directivity of the antenna in a vertical plane. And a plurality of base stations having, and collectively controls the directivity changing means of the plurality of base stations,
A zone change system comprising: a control device that changes zones of the plurality of base stations by changing directivity in a vertical plane of the antenna. 3. The zone change system according to claim 2, wherein the control device changes zones of the plurality of base stations in consideration of traffic of the plurality of base stations. 4. The antenna according to claim 1, wherein the antenna is an array antenna,
4. The apparatus according to claim 1, wherein the directivity changing unit changes the directivity of the antenna in a vertical plane by changing a phase of a transmission signal supplied to the array antenna.
The zone change system according to any one of the above.