JPH09298766A - Mobile communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide proper service by conducting dynamically variable control of a service area of a radio base station timewise continuously. SOLUTION: A variable service area control circuit 34 in a mobile communication exchange station 3.1 generates tilt angle control information 102 to control each antenna tilt angle of radio base stations 1.1-1.n based on traffic information 103 and communication control information 101. Thus, the tilt angle is continuously controlled timewise depending on an actual traffic state or the like and the service area is properly controlled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication system, and more particularly to a radio base station serving as a base station for mobile communication terminals within a service area and a mobile switching center interconnected with the radio base station by a transmission line network. The present invention relates to a mobile communication system having the same.

[0002]

2. Description of the Related Art In a conventional mobile communication system, the range of a so-called service area covered by a radio base station is fixedly determined. In this case, in order to optimally secure the service area, the tilt angle of the antenna is adjusted at the time of initial setting.

As an example thereof, there is a technique disclosed in Japanese Patent Laid-Open No. 5-37222, in which a phase adjuster is inserted after a distributor for distributing a high frequency signal to a plurality of antenna elements to feed each element. The phase of each high-frequency signal to be generated can be individually adjusted by the phase adjuster, and the phase adjuster can adjust the phase based on the control signal.

In this way, by controlling the phase adjuster to adjust the phase of the high frequency signal fed to each element,
It is designed to adjust the tilt angle of the antenna.

[0005]

In the prior art of this type, a control signal is supplied from a remote place to control the phase adjuster, and the operation of adjusting the tilt angle on the spot is not required and the antenna can be easily managed. However, this tilt angle adjustment is not always performed, but is used for tilt angle adjustment during maintenance work, etc. It is used statically and fixedly.

On the other hand, in the mobile communication system, the traffic volume continuously and temporally changes depending on the time zone, the season, the period, etc. For example, the traffic information (the number of incoming and outgoing calls) as shown in FIG. It is actually observed.

Therefore, in actual system operation, it is the actual situation that the configuration of the radio base station is systematically determined by assuming the mutual arrangement of service areas and the traffic volume.

At this time, if there is a difference between the assumption and the actual situation, congestion, interference, etc. occur due to the imbalance in the traffic volume between the service areas, resulting in deterioration of service.

Therefore, the present invention has been made to solve the drawbacks of the prior art, and the purpose thereof is to provide an appropriate service that matches the actual operating state of traffic and the like. Mobile communication system.

[0010]

According to the present invention, there are provided a radio base station serving as a base station for mobile communication terminals within a service area, and a mobile switching center interconnected with the radio base station by a transmission line network. A mobile communication system having the control means, provided in the mobile switching center, for generating control information for variably controlling a service area of the radio base station according to a procedure programmed by an operator, and provided in the radio base station. , A service area changing means for changing the service area based on the control information.

The program is characterized in that service area variable information is set in advance in accordance with parameter information such as a day of the week, a time zone, and a place.

Further, according to the present invention, a mobile communication system having a radio base station serving as a base station for mobile communication terminals within a service area, and a mobile switching center interconnected with the radio base station by a transmission line network. In the mobile switching center, control means for generating control information for variably controlling a service area of the radio base station according to traffic information, and provided in the radio base station, based on the control information. There is provided a mobile communication system including a service area changing means for changing the service area.

The control means generates the control information according to the reception level and the reception sensitivity information in the service area, and also generates the control information according to preset service area setting information. It is characterized by that.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The operation of the present invention will be described. The tilt angle of the antenna is variably controlled according to the traffic state that changes moment by moment, and the tilt angle is variably controlled according to the day of the week, time, season, and even the period such as events to put the service area into actual operation. Properly control accordingly.

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

FIG. 1 is a system block diagram of the present invention. A plurality of wireless base stations 1.1 to 1. n are provided, and each of these radio base stations is a base station for the mobile communication terminal 4 in the service area.

Each antenna of these radio base stations has a structure in which the tilt angle described above is controllable, and the service area can be changed by controlling the tilt angle.

These radio base stations 1.1 to 1. n is connected to a plurality of mobile communication exchanges 3.1 to 3.2 via a transmission line network 2, and each of these mobile communication exchanges is further connected to a public line network (not shown).

The mobile communication exchanges 3.1 and 3.2 have the same configuration, and therefore, a block example of only the mobile communication exchange 3.1 is shown, and the base station controller 31 and the mobile communication exchange 32 are shown. And a maintenance and operation device 33 and a variable service area control device 34.

The maintenance operation device 33 is a base station control device 31.
The communication control information 101 sent from the variable service area control device 34 is sent to the variable service area control device 34, and the traffic information 103 sent from the exchange (not shown) via the mobile communication switching center 32 is sent to the variable service area control device 34. To do.

The communication control information 101 is for each mobile communication terminal 4
The traffic information 103 is information indicating a traffic state sent from the exchange, that is, traffic volume (call volume) information per unit time.

The variable service area control device 34 variably controls the tilt angle of the antenna of the radio base station according to the information 101 and 103 and the external control information input from the external control terminal 5.1. The control information 102 is generated. According to the control information 102, the tilt angle of the antenna of the wireless base station is appropriately changed, and the service area is dynamically controlled so that it is always appropriate.

FIG. 2 is a block diagram showing the details of the mobile switching center 3.1 of FIG. 1, and the same parts as those of FIG. 1 are designated by the same reference numerals. The base station control device 31 in FIG. 1 comprises a multiplexing unit 310 and a base station control unit 311 as shown in FIG. 2, and the mobile communication switching center 32 in FIG. 1 comprises a switching system 320.

The multiplexing unit 310 multiplexes the transmission path between the mobile communication switching center 3.1 and the radio base station 1.1, and the switching system 320 connects between the public line network and the mobile communication terminal 4. Make an exchange connection.

The maintenance operation device 33 in FIG. 1 includes a maintenance operation unit 320 and a traffic data collection unit 331 in FIG.
The traffic data collection unit 331 collects various kinds of traffic information (number of incoming and outgoing calls, congestion, CPU usage rate, etc.) 103 transmitted from an exchange (not shown) (from the exchange system 320 via the maintenance operation unit 320). Then, while editing the graph as shown in FIG. 8, the information is sent to the variable service area control device 34 through the maintenance operation unit 330.

FIG. 3 shows the radio base stations 1.1 to 1. 3 is a block diagram of each specific example of n, and includes a multiplexing unit 20, a base station radio unit 21, a tilt angle variable antenna 22, and a tilt angle variable control unit 23. The tilt angle variable control unit 23 receives the tilt angle control information 102 multiplexed on the transmission line network 2 from the mobile switching center, and variably controls the tilt angle of the antenna 22 to perform variable control of the service area.

The base station radio section 21 modulates and amplifies the signal, transmits radio waves to the mobile communication terminal 4 via the antenna 22, and vice versa, transmits radio waves from the mobile communication terminal 4 to the antenna 2.
2 to amplify, demodulate and transmit to the mobile communication switching center.

FIG. 4 is a block diagram showing an example of the variable service area control device 34. Referring to FIG. 4, it comprises a control circuit 340, a memory 341, a plurality of setting changeover switches 342, and a timer 343.

Setting changeover switch 342 (keyboard)
Allows service area control information (tilt angle control information) according to the situation such as "crowded / event / weekday" to be input to the control circuit 340, and the switch 2 can be operated in units of radio base stations. For example, it has a man-machine interface configuration in which a touch sensor and a screen are combined.

When the setting information is input by the setting switches 342, the control circuit 340 reads the tilt angle setting data for each station from the memory 3, and the tilt angle variable control information 10 is read.
Output as 2, and when set to "Manual",
Any tilt angle can be set, and the data at this time is stored in the memory 3. The above operation is hereinafter referred to as "preset mode".

By combining the preset mode with the timer 5, the tilt angle setting data is read from the memory 3 according to the day of the week, the time, etc., and the tilt angle variable control information 102 is automatically transmitted. . This operation is hereinafter referred to as "program mode".

Even if the preset mode or the program mode is set, the tilt angle variable control signal 102 is continuously and temporally generated according to the traffic information 103 and the communication control information 101. Hereinafter referred to as "dynamic mode".

The tilt angle can also be variably controlled by an external control signal input from the external control terminal 5.1.

FIG. 5 is a control flow chart showing the operation of the control circuit 340. Referring to FIG. 5, first, it is determined whether or not there is a mode change (step S1). This judgment is judged whether it is one of the preset, program, and dynamic modes (step S2). In this mode, the operator (operation operator) operates the keyboard 342.
Is specified by

The operator designates the preset mode, the program mode, and the dynamic mode according to the situation (steps S3 to S5). In response to the designation of the preset mode, the mode is changed to the change point input mode (step S
6) If there is a change, the data is input from the keyboard 342 according to the change and the data is stored in the memory 3
It is written in 41 (steps S8, S10).

For example, when the program mode cannot cope with such a case that some special event occurs, the setting can be changed by the preset mode so that the tilt angle variable control data can be changed.

In response to the designation of the program mode (step S4), the operator confirms the content of the parameter for tilt angle variable control (steps S7, S).
9). That is, the parameters such as the day of the week, the time zone, the weather, and the control interval are checked and stored in the memory 341 (step S11).

For example, in the evening on a rainy day (17: 00-18: 30)
The control parameter for setting the tilt angle is written in 0 minutes) and particularly in an area on Friday (for example, an area around the exit of the main terminal station).

Thereafter, in the preset mode and the program mode, while the stored data is read from the memory 341 (steps S13 and S14), the tilt angle is determined and each tilt control is performed (steps S15 and S16).

In the dynamic mode, the tilt angle determination control is performed according to the traffic information and communication control information (steps S12, S15, S16). For example,
The control based on the traffic information is performed as follows.

Here, the traffic volume refers to the total time during which a line or equipment is held for a certain period of time, and if the traffic volume per unit time is defined as the call volume, call volume (A) = number of calls (C) x average holding time (H) [er
l]. Here, the number of calls (C) is the call itself or a call request, and the average hold time (H) is the time that the call occupies the device.

The call volume (A) is calculated for each area, and the area where calls are concentrated is determined by the reception level (call control information) reported by each mobile communication terminal 4.
The tilt angle for the required electric field strength is determined, and the tilt angle is controlled.

The variable range of the service area by the control of the tilt angle is shown in FIG. 6, and the service area can be expanded as the tilt angle approaches 0 °.

At the time of controlling the tilt angle, the tilt angles (service areas) of the radio base stations 1.1 to 1.3 (see FIG. 7) in the adjacent areas are also interfered by the mobile radio terminal 4 as deterioration of the reception sensitivity. Since the occurrence is reported (communication control information), adjustment control is performed in association with each other to prevent the dead zone (electric field lowering portion) of the area from occurring. An example is shown in FIG.

Therefore, when a large number of calls are generated at a specific location in a certain area, the tilt angle is controlled to be narrowed to increase the electric field strength, and the area of an adjacent radio base station is expanded in the tilt angle. Control to cover the area.

The relationship between the tilt angle and the electric field strength measurement data as shown in FIG. 6 is stored in advance in a memory or the like as a database, and the tilt angle is determined with reference to this database.

Whether or not there is a change in the control data or mode is always checked (steps S17 and S18), and if there is a change, the above steps are repeated accordingly.

[0048]

As described above, according to the present invention, the variable control of the service area is performed continuously in time according to the traffic information and the communication control information. Therefore, it is possible to appropriately control the service area according to the traffic state. The effect is that services can be provided.

In addition to the control in the so-called dynamic mode based on the traffic information and the communication control information, the control in the preset mode and the program mode is possible, so that the manual setting control or the special setting which is difficult in the manual setting control is possible. There is an effect that the tilt angle can be flexibly controlled even when an event occurs.

[Brief description of drawings]

FIG. 1 is a system block diagram of an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a mobile communication switching center in the block of FIG.

FIG. 3 is a diagram showing an example of a radio base station in the block of FIG.

FIG. 4 is a block diagram showing an example of a variable service area control device in the block of FIG.

FIG. 5 is a flowchart showing the operation of the embodiment of the present invention.

FIG. 6 is a diagram showing the relationship between the tilt angle of the antenna and the electric field strength.

FIG. 7 is a conceptual diagram of a variable service area between adjacent base stations.

FIG. 8 is a diagram showing an example of changes in traffic information.

[Explanation of symbols]

 1.1-1. n Radio base station 2 Transmission line network 3.1, 3.2 Mobile communication exchange station 4 Mobile communication terminal 20 Multiplexing unit 21 Base station radio unit 22 Tilt angle variable antenna 23 Tilt angle variable control unit 31 Base station control device 32 Mobile communication switching center 33 Maintenance / operation device 34 Variable service area control device 310 Multiplexing unit 311 Base station control unit 320 Switching system 330 Maintenance / operation unit 331 Traffic data collection unit 340 Control circuit 341 Memory 342 Changeover switch 343 Timer

Claims (6)

[Claims] 1. A mobile communication system comprising: a radio base station serving as a base station for a mobile communication terminal within a service area; and a mobile switching center interconnected with the radio base station by a transmission line network. Control means provided in the exchange and generating control information for variably controlling the service area of the radio base station according to a procedure programmed by an operator; and the control means provided in the radio base station, the service area being based on the control information. A mobile communication system comprising: a variable service area changing means. 2. The mobile communication system according to claim 1, wherein the program has service area variable information set in advance in accordance with parameter information such as a day of the week, a time zone, and a place. 3. A mobile communication system comprising: a radio base station serving as a base station for a mobile communication terminal within a service area; and a mobile switching center interconnected with the radio base station by a transmission line network. Control means provided in the exchange and generating control information for variably controlling the service area of the radio base station according to traffic information; and control means provided in the radio base station for varying the service area based on the control information. A mobile communication system comprising: a service area changing means. 4. The mobile communication system according to claim 3, wherein the control unit is configured to generate the control information according to a reception level and reception sensitivity information in the service area. 5. The mobile communication system according to claim 1, wherein the control means is configured to generate the control information in accordance with preset service area setting information. 6. The mobile communication system according to claim 1, wherein the service area changing means is an antenna whose tilt angle is controllable according to the control information.