JPH06245260A - Base station control system - Google Patents

Abstract

PURPOSE:To suppress the increase in a channel switching number attended with the increase in a speed of a mobile body. CONSTITUTION:When a mobile body moves a communication available area covered by plural base station 4 while making a communication, the base station control system makes changeover of channels among accent cells 11. The system is provided with a speed sensor 5 monitoring the mobile speed of a mobile body, a mean speed discrimination device 6, a channel changeover number counter 7 monitoring a channel changeover number, an antenna with a directivity to change a cell diameter of each base station 4 and an antenna controller 8 adjusting the cell diameter when the mobile speed or the like exceeds a threshold level or stops the transmission of the base stations 4. When the threshold level is exceeded through the monitor of the mobile speed or the like, the antenna controller 8 decreases the cell diameter at a predetermined interval or stops the transmission thereby reducing the number of cells passed by the mobile body and reducing the number of switched channels.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a base station control system for reducing the number of channel switching during mobile communication.

[0002]

2. Description of the Related Art In mobile communication, a plurality of base stations are arranged in an area which is a specific area where communication is possible, and a plurality of cells which are communication areas of one base station are combined to cover the entire area. Has become. Then, when the mobile unit moves from one cell to the adjacent cell, a so-called channel switching operation is performed in which the channel communicating with the base station of the original cell is switched to communicate with the base station of the next cell. To do.

[0003]

By the way, in the previous mobile communication, the cell radius is as large as several km, and even if the mobile body moves at a high speed, it takes a proper time to move from one cell to the next cell. However, the number of channel changes was not large.

However, if the conventional channel switching system is directly applied to the microcell system, the number of channel switching becomes very large as the speed of the moving body increases. This relationship is shown in FIG. This figure shows a car equipped with a telephone as a moving body on a straight road
This is the result of a simulation in which a phone was used at a rate of 0.3 erlangs, with each car running at a rate of 0.3.
Cars run at six different speeds. As can be seen from this figure, the change in the number of channel changes due to the difference in cell radius increases as the speed of the moving body increases.

Therefore, if the number of channel switching increases as the speed of the moving body increases, there is a problem that the load on the network system, particularly the channel switching system, becomes very large.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a base station control system capable of efficiently suppressing an increase in the number of channel switchings due to an increase in the speed of a mobile unit. And

[0007]

In order to solve the above-mentioned problems, a first aspect of the present invention is directed to a case in which a mobile object is adjacent to each other when a mobile object moves while communicating in a specific communicable area covered by a plurality of base stations. In a base station control method for channel switching between cells, a monitoring unit that monitors the moving speed of the mobile unit or the number of channel switching, a cell radius control unit that changes the cell radius of each base station, and a mobile unit that moves by the monitoring unit. And a base station control means for adjusting the cell radius by the cell radius control means when the speed or the number of channel switching exceeds a preset threshold value.

A second aspect of the present invention is a base station control method for performing channel switching between adjacent cells when a mobile body moves while communicating in a specific communicable area covered by a plurality of base stations. Monitoring means for monitoring the moving speed of mobiles or the number of channel switching, base station suspension means for suspending continuously arranged base stations at regular intervals, and cell radius control means for changing the cell radius of each base station. And when the moving speed or the number of channel switching by the monitoring means exceeds a preset threshold, the base station pause means pauses the base stations at regular intervals, and the cells of the base stations remaining by the cell radius control means And a base station control means for enlarging the radius to cover the entire specific area.

[0009]

According to the first aspect of the present invention, when the mobile body is moving while communicating, the monitoring means monitors the moving speed of the mobile body or the number of channel switching. In the base station control means, the moving speed or the number of channel switching by the monitoring means is compared with a preset threshold value, and when the moving speed or the like exceeds the threshold value, the cell radius control means adjusts the cell radius. Specifically, the cell radius is reduced at regular intervals and the radius of the remaining cells is increased to cover the entire specific area.

Further, in the second invention, when the moving speed or the like exceeds a threshold value, the base station suspending means suspends the base station at regular intervals. The remaining base stations expand the cell radius by the cell radius control means to cover the entire specific area.

As a result, the number of cells through which the mobile unit passes can be reduced and the number of channel switching can be reduced.

[0012]

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

The overall configuration of the network system to which the base station control method of this embodiment is applied is as shown in FIG.
From a control station 3 provided with a controller 1, a channel switching control device 2, etc., a plurality of base stations 4 respectively controlled by the control station 3, and a speed sensor 5 for measuring the speed of a mobile body (not shown). It is roughly configured.

The controller 1 determines the average speed of the moving body based on the detection value from the speed sensor 5, and the channel switching which counts the number of channel switching by the channel switching information from the channel switching control device 2. The number counter 7 and the antenna control device 8 that controls the antenna of each base station 4 based on the information from the average speed determination device 6 or the channel switching number counter 7. Each base station 4 is provided with an antenna that has directivity and can control the azimuth angle to control the radius of the cell 11 and the shape of the cell 11 itself. The antenna control device 8 controls the azimuth angle or the radio transmission power of the antenna provided in each base station 4 to adjust the radius of the cell 11. Alternatively, the shape of the cell 11 itself is adjusted by adjusting the azimuth angle of the antenna.

In this embodiment, one controller 1
Therefore, the area 12 constituted by the cells 11 of the five base stations 4 is a range that can be controlled by one controller 1. Control station 3 equipped with this controller 1
And a plurality of five base stations 4 forming one area 12 are arranged as one unit to form a mobile communicable area.

In the above structure, the speed sensor 5 and the average speed determination device 6 or the channel switching control device 2 are used.
The channel switching number counter 7 constitutes monitoring means, the antenna of the base station 4 constitutes cell radius control means, and the antenna control device 8 constitutes base station control means. Also,
The antenna control device 8 also has a function as a base station suspension means.

Next, base station control using the above apparatus will be described.

In this control, as shown in FIG. 2, when the radius of the cell 11 is increased when the speed of the moving body is increased,
This control was devised by paying attention to the fact that the number of cells 11 through which a mobile body passes is reduced and the number of channel switching can be suppressed to a small value. That is, as shown in FIG. 3, when the speed of the moving body is small (line A) with respect to the cell 11 having the radius a, the number of channel switching is the numerical value c. When the speed is increased (line B), the channel switching number becomes the numerical value d, but when the cell 11 is expanded to the radius b, the channel switching number decreases from the numerical value d to the numerical value c.

Based on the above concept, the antenna of each base station 4 is controlled by the antenna controller 8 and the radius of the cell 11 is adjusted appropriately with a threshold value set in advance. The threshold value for control by the antenna control device 8 is appropriately set in consideration of the size of the cell 11 and the allowable capacity of the controller 1. FIG. 4 is a diagram showing the relationship between the speed of the moving body and the number of channel switching in each case where the radius of the cell 11 is doubled to 2r. As shown in the figure, if the speed of the moving body increases from Y to X, the number of channel switching increases from Y ″ to X ″, but if the radius of the cell 11 is doubled, the number of channel switching can be significantly reduced. it can. Therefore, as an example, X and Y are threshold values.

The concrete control by the antenna control device 8 is to control each of the base stations 4 arranged in a continuous manner at regular intervals so that the radius of the cell 11 of the remaining base stations 4 is increased, and at a regular interval. There is control to decrease the radius of the cell 11 and increase the radius of the remaining cells 11. Further, the means for detecting the threshold value may be determined from the average speed of the moving body, or may be directly counted from the number of channel switching. Further, the interval for suspending the base station 4 is also 1
It is appropriately adjusted according to the speed of the moving body, such as every two or two. In the following description, a case will be described in which every other base station 4 is suspended, the radius of the remaining cell 11 is doubled, and it is further determined whether or not the threshold value is exceeded from the average speed of the mobile body. In this embodiment, the threshold values are X and Y. Here, the threshold value X is a threshold value when the moving body speeds up, and the threshold value Y is a threshold value when the moving body slows down. The threshold Y is set to a value smaller than the threshold X because when the average speed of the moving body is near the threshold Y, the radius of the cell 11 changes frequently and the communication is unstable. This is to prevent the phenomenon.

The radius of the normal cell 11 is r. The speed information of the mobile body communicating with each other while moving in the cell 11 having the radius r of each base station 4 is detected by the speed sensor 5 and sent to the average speed determination device 6. The average speed determination device 6 determines the average speed of the moving body based on the information from the speed sensor 5 and sends it to the antenna control device 8. The antenna control device 8 compares the average speed of the moving object with a preset threshold value, and performs normal control unless the average speed exceeds the threshold value. That is, all base stations 4 are formed with cells 11 each having a radius r, as shown in FIG.

When the average speed from the average speed determination device 6 exceeds the threshold value X, the antenna control device 8 causes the antenna control device 8 shown in FIG.
, The rest base station 4B is put to rest and the remaining base stations 4A are adjusted so as to widen their azimuth angles or be adjusted so as to increase the wireless transmission power so that the radius of the cell 11 becomes 2r. .

As a result, the number of cells 11 in the area 12 is halved, and the number of channel switching is greatly reduced.

When the velocity of the moving body decreases and the average velocity from the average velocity determining device 6 falls below the threshold value Y, the antenna control device 8 causes the suspended base station 4B as shown in FIG. 5 (A). The cell 11 having the radius r is formed by restarting, and the azimuth angle or the radio transmission power of the remaining base station 4A is adjusted to set the radius of the cell 11 to r to restore the normal state.

In the above-described embodiment, the base stations 4 are hibernated every other one as a mode of hibernation of each base station 4. However, as shown in FIGS. 6A and 6B, every two base stations 4 are hibernated. Alternatively, the base station 15B may be suspended. In this case, the radius of the expanding microcell 14 is 1.5 times (1.5r) the original radius r. Furthermore, two adjacent base stations 15
Since the distance of the cell 14 in the portion between the two may be r, the shape of the cell 11 may be a shape corresponding to the above conditions by utilizing the directivity of the antenna. It may be three or more depending on the speed of the moving body.

Further, in the above embodiment, the base station 4 is made to completely stop at a fixed interval, but the purpose of this control is the cell 1 which the mobile body passes through when moving in the area 12.
Since the number of 1's is reduced to suppress the number of channel switching, the same action and effect as described above can be obtained even when the radius of the cell 11 is made significantly smaller than when the base station 4 is completely stopped. Can be played. In addition, as the adjustment of the radius of the cell 11, the radius of the cell 11 can be reduced by adjusting the azimuth angle of the antenna or the radio transmission power as in the above.

Further, in this embodiment, the average speed of the moving body is used as the information for judging the threshold value, but the number of channel switching may be directly counted. That is, a threshold value of the number of channel switching is set in advance, the number of channel switching is counted by the channel switching number counter 7 based on the channel switching information from the channel switching control device 2, and the number of channel switching and the threshold value are set. And the same control as above is performed. Also by this, the same operation and effect as the above-mentioned embodiment can be obtained.

[0028]

As described above in detail, according to the present invention, when the speed of a mobile unit or the number of channel switching exceeds a threshold value, the base station is paused at regular intervals or the cells are switched at regular intervals. The number of cells through which the moving body passes can be reduced by reducing the radius of the. As a result, the number of channel switching can be greatly reduced and the load on the system can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a network system for implementing a base station control method according to the present invention.

FIG. 2 is a graph showing the relationship between the cell radius and the number of channel switchings when the speed of the moving body is changed.

FIG. 3 is a graph showing a change in the number of channel switching when the cell radius is changed with respect to a difference in speed of a moving body.

FIG. 4 is a graph showing the relationship between the speed of a mobile unit and the number of channel changes with respect to the difference in cell radius.

FIG. 5 is a schematic diagram showing a control mode when each other base station is paused.

FIG. 6 is a schematic diagram showing a control mode when each two base stations are suspended.

[Explanation of symbols]

1 ... Controller, 2 ... Channel switching control device, 3
... Control station, 4 ... Base station, 5 ... Speed sensor, 6 ... Average speed determination device, 7 ... Channel switching number counter, 8 ... Antenna control device, 11 ... Cell.

Claims (2)

[Claims] 1. A base station control method for performing channel switching between adjacent cells when a mobile body moves while communicating in a specific communicable area covered by a plurality of base stations, the movement of the mobile body. Monitoring means for monitoring the speed or the number of channel switching, cell radius control means for changing the cell radius of each base station, and the cell when the moving speed or the number of channel switching exceeds a preset threshold by the monitoring means A base station control method comprising: a base station control means for adjusting a cell radius by a radius control means. 2. A base station control method for performing channel switching between adjacent cells when a mobile unit moves while communicating in a communicable specific area covered by a plurality of base stations, the movement of the mobile unit. Monitoring means for monitoring the speed or the number of channel switching, base station pausing means for pausing continuously arranged base stations at regular intervals, cell radius control means for changing the cell radius of each base station, and the monitoring When the moving speed or the number of channel switching exceeds a preset threshold value by means, the base station pause means pauses the base stations at regular intervals, and the cell radius control means expands the cell radius of the remaining base stations. A base station control method, comprising: a base station control unit that covers the entire specific area.