JP3153196B2 - Traffic distribution method in mobile communication system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automobile (mobile) telephone system, a simplified portable telephone system (PHS),
The present invention relates to a traffic distribution method based on a change in the number of used communication channels in a business office type private system.

[0002]

2. Description of the Related Art Conventionally, as an example of a traffic distribution method in a mobile communication system, Japanese Patent Application Laid-Open No. 6-69860 has been proposed.
Japanese Patent Application Laid-Open Publication No. H11-163873 discloses a technique for controlling congestion of a communication channel by controlling transmission power of a broadcast channel from the base station in accordance with a change in the usage rate of the communication channel of the base station. Further, Japanese Patent Application Laid-Open No. 9-98486 discloses a control method in which a base station having a large traffic is specified in advance, communication is performed between the base stations using a dedicated line, and a call is connected to another base station having a low traffic. ing.

[0003]

However, a first problem of the prior art is that an area in which a plurality of base stations are installed calls a certain base station in spite of low traffic of other base stations. Is extremely concentrated, and mobile stations waiting for the base station cannot make or receive calls. The reason for this is that the traffic volume (traffic) in a region is usually estimated and the number of base stations installed in the region is determined. For example, the number of communication channels is increased by increasing the number of base stations in an area where traffic is predicted to be high. However, there is a possibility that a traffic exceeding a prediction may be generated due to a disaster or an event. In addition, in the current mobile communication system, when a mobile station scans a base station, a radio channel with a high reception level is used preferentially, so calls are concentrated on a certain base station even in a place where a plurality of base stations are installed. there's a possibility that.

[0004] The second problem is that, even though the communication channel usable by the base station is lost, it cannot be recognized that the mobile station waiting for the base station cannot make or receive a call.
If you make a call from that mobile station, you will get a misunderstanding that the other party is busy. In addition, useless redialing causes congestion of the control channel of the base station. The reason is that the waiting mobile station has no means for detecting the base station busy information.

Accordingly, an object of the present invention is to provide control means for distributing traffic to another base station having low traffic when calls are concentrated on one base station.

It is another object of the present invention to provide a control means for notifying the mobile station waiting for the base station of the information when there is no available communication channel, thereby preventing congestion of the control channel. I have.

[0007]

[Means for Solving the Problems]

[0008] The present invention for solving the aforementioned problem, based on
Multiple adjacent bases where the wireless area of the base station and the base station overlap
Mobile communication system composed of a mobile station and a plurality of mobile stations.
A traffic distribution method, wherein the base station
The base station indicates that the incoming call has begun to concentrate on the base station
A first threshold on the number of used communication channels of
Available communication channels where calls remain concentrated at the base station
Communication channel in use of the base station, indicating that the
A second threshold for the number of channels is set,
The base station determines the number of used communication channels of the base station.
Monitoring the number of used communication channels to a first threshold
Over all mobile stations of the base station
Performs a handover instruction and transfers during the call receiving the instruction.
The mobile station investigates the connection destination base station and checks the radio area of the base station.
Received an indication that it is located in the adjacent base station area where
During a call, the mobile station performs a handover to the adjacent base station.
Call, and the base station's wireless area overlaps
In-call movement instructed not located in base station area
The station does not hand over to another base station and
And then the base station continues to
Monitor the number of used communication channels of the base station , and
If the number of communication channels exceeds the second threshold,
All waiting mobile stations of the local station are in different base stations
In the standby mode.
The mobile station investigates the connection destination base station and checks the radio area of the base station.
Received an indication that it is located in the adjacent base station area where
The waiting mobile station moves to the adjacent base station and waits.
Only continued, adjacent base the wireless area of the base station overlap
Waiting for an instruction that is not located in the station area
The station does not move to another base station and waits for the original base station.
I try to continue .

[0009]

[0010]

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

Referring to FIG. 1, a mobile communication system to which the present invention is applied includes a base station 1 and a mobile station 2.

The base station 1 includes a first high traffic detection means 11, a first high traffic distribution means 12, a second high traffic detection means 13, and a second high traffic distribution means 1.
4, a base station busy detecting means 15 and a base station busy notifying means 16 are provided.

The mobile station 2 includes a first high traffic distribution unit 21, a second high traffic distribution unit 22, and a base station busy response unit 23.

The first high traffic detecting means 1 of the base station 1
1 detects whether the traffic has exceeded threshold 1. Then, the base station first high traffic distribution means 12 and the first high traffic distribution means 21 of the mobile station communicate with the mobile station of the base station 1 which is located in a radio area overlapping with another base station having low traffic. Handover to the other base station.

The second high traffic detecting means 13 of the base station 1 detects whether the traffic has exceeded the threshold value 2 or not.
Then, the second high traffic distribution means 14 of the base station 1 and the mobile station second high traffic distribution means 22 detect a mobile station waiting for the base station 1 which is located in a wireless area overlapping with another base station having low traffic. The base station is located in the different base station.

Further, the base station busy detecting means 15 detects whether there is no available communication channel of the base station 1 or not. Then, the base station busy notifying unit 16 notifies the mobile station 2 waiting for the base station 1 of the base station busy / ready information.

Upon receiving the base station busy information, the base station busy correspondence means 23 of the mobile station 2 sets the mobile station 2 in a call-disabled standby mode and displays the base station busy information on the display of the mobile station 2. When the base station ready information is received, the mobile station 2 is set to the call waiting mode, and the base station busy information displayed on the display of the mobile station 2 is turned off.

Next, the method of the present invention will be described with reference to FIGS.

The base station monitors whether the number of used communication channels exceeds the threshold value 1 (step 11 in FIG. 2). The threshold 1 is a threshold indicating that calls start to concentrate on the base station. The specified threshold value 1 is determined in consideration of the maximum number of usable communication channels of the mobile communication system base station, the arrangement of the base stations (range of the wireless area overlapping between the base stations), and the like.

When the number of used communication channels of the base station exceeds the threshold value 1, the mobile station communicating with the base station is handed over to another base station with low traffic (steps 121, 122, 123, 124, (Fig. 3).

The base station BS1 instructs the mobile station during a call of the base station to perform a handover due to high traffic in the order of decreasing reception level. Upon receiving the instruction, the mobile station scans the connected base station. A mobile station of the base station located in a radio area overlapping with another base station B2 with low traffic finds the other base station B2, issues a reconnection request to the other base station B2, and reconnects from the other base station B2. Get confirmation. An authentication request, an authentication response, and a communication channel activation are performed, and the communication is continued using the base station B2. Base station B1
When the handover timer started when issuing the handover instruction times out, the communication channel used by the mobile station is released. A mobile station during a call that is not located in a wireless area overlapping another base station with low traffic does not find another base station, returns to the original base station, and continues the call.

The base station performs the above-described handover process on all the mobile stations during a call in the order of lower reception level (step 125 in FIG. 2).

Next, the base station monitors whether the number of busy communication channels exceeds the threshold value 2 (step 13 in FIG. 2). Here, the threshold value 2 is a threshold value indicating that calls are concentrated on the base station and the remaining usable communication channels are extremely small.
The prescribed threshold value 2 is determined in consideration of the maximum number of usable communication channels of the mobile communication system base station, the arrangement of the base stations (range of the wireless area overlapping between the base stations), and the like.

The number of communication channels in use by the base station is equal to the threshold value 2
Is exceeded, the mobile station waiting for the base station is located in another base station (step 14 in FIG. 2).

That is, the base station instructs the waiting mobile station to be located in another base station using the broadcast information. The waiting mobile station that has received the instruction scans another base station. A waiting mobile station located in a wireless area overlapping with another low-traffic base station finds the above-mentioned another base station and waits at the another base station. On the other hand, a waiting mobile station that is not located in a wireless area overlapping with another base station with low traffic does not find the other base station, returns to the original base station, and stands by.

The base station monitors whether all communication channels are in use (step 15 in FIG. 2).

That is, when all the communication channels are used, the base station busy of the base station is notified by the broadcast information to the mobile station waiting for the base station (step 16 in FIG. 2).
1). The waiting mobile station that has received the notification enters the outgoing call waiting state from the outgoing / incoming ready state. Then, it displays on the display that the current base station is busy and cannot make a call, and notifies the user of the mobile station. If there is a communication channel that can be used again due to the release of the communication channel of the base station, the base station notifies the mobile station of the base station in a call-disabled standby state of the base station ready with broadcast information (step 162 in FIG. 2) ). The mobile station that has received the notification returns to the transmission / reception permission standby state. Then, the base station busy information displayed on the display is turned off.

Next, the present invention will be described more specifically with reference to FIG. As shown in FIG. 4, mobile stations MS1, M
S2, MS3, MS4 and MS5 are located in the wireless area A1 of the base station BS1. The mobile stations MS8 and MS9 are located in the wireless area A2 of the base station BS2. Furthermore,
The mobile stations MS6 and MS7 are in the radio area A1 of the base station BS1.
And the wireless area A2 of the base station BS2.

It is assumed that the maximum number of usable communication channels of each of the base stations BS1 and BS2 is four. Mobile stations MS1, MS2, MS3, MS4, MS5,
The mobile stations MS6 and MS7 perform position registration with the base station BS1 and assume that they are waiting. In addition, MS8 and MS9 register their positions in base station BS2, and assume that they are waiting.

The traffic thresholds 1 and 2 of the base stations BS1 and BS2 are the same,
"2" is assumed.

When the mobile station MS7 enters a call, the base station B
The number of used communication channels in S1 is one. In this state, since the threshold value 1 is not exceeded, the first high traffic distribution is not performed.

When the mobile station MS8 enters a call, the number of used communication channels of the base station BS2 becomes one. But,
Since the threshold value 1 is not exceeded, the first high traffic distribution is not performed.

When the mobile station MS1 enters a call, the number of used communication channels of the base station BS1 becomes two. However, since the threshold value 1 is not exceeded, the first high traffic distribution is not performed.

Further, when the mobile station MS2 is busy, the number of busy communication channels of the base station BS1 becomes three. Therefore, in this state, since the threshold value 1 is exceeded, the base station BS1 communicates with the mobile stations MS7, MS7 of the base station during a call.
1. The first high traffic distribution is performed on the MS2 in the order of the reception level being low. The order is MS7, MS1, M
In S2, first, the base station BS1 issues a high traffic handover command to the mobile station MS7.
Then, the mobile station MS7 performs a handover to the base station BS2 adjacent to the base station BS1, and continues the call using the base station BS2.

For this reason, the channel of BS1 used by MS7 is released.

Next, the base station BS1 issues a handover command for high traffic to the mobile station MS1.
Since the mobile station MS1 is not located in a wireless area where another base station whose traffic is low with the base station BS1 is not located, the mobile station MS1 returns to the base station BS1 and continues the call using the base station BS1.

Next, the base station BS1 issues a high traffic handover command to the mobile station MS2. Mobile station M
Since S2 is not located in a wireless area where another base station having low traffic with the base station BS1 overlaps, the mobile station returns to the base station BS1 and continues the call using the base station BS1.

Therefore, at this time, the number of used communication channels of the base station BS1 changes from 3 to 2, and the number of used communication channels of the base station BS2 changes from 1 to 2.

Further, when the mobile station MS3 enters a call, the number of used communication channels of the base station BS1 changes from 2 to 3, and
Since the threshold value 1 has been exceeded, the base station BS1 performs the first high traffic distribution to the mobile stations MS1, MS2, and MS3 during the call of the base station in descending order of the reception level. Mobile station MS
1, MS2 and MS3 are not located in a wireless area where other base stations having low traffic with the base station BS1 overlap.
The handover cannot be performed to another base station, and the call is continued using the base station BS1.

Accordingly, the number of used communication channels of the base station BS1 remains at 3 and exceeds the threshold 2, so that the base station BS1
Are the mobile stations MS4, MS5, MS waiting for the base station.
In response to No. 6, an instruction is provided to other base stations with low traffic. Since the mobile station MS6 is located in the wireless area where the base station BS1 and the low traffic base station BS2 overlap,
It is located in the base station BS2 and enters a state of waiting. Mobile station M
Since S4 and MS5 are not located in the wireless area where the base station BS1 and the other base stations with low traffic overlap, the MS5 does not find any other base station and stays in the base station BS1 and enters a state of waiting.

Next, when the mobile station MS4 enters a call,
The number of used communication channels of the base station BS1 is changed from three to four. The mobile stations MS1, MS2, MS during a call of the base station
3. Since the MS 4 is not located in a wireless area overlapping with another base station whose traffic is low with respect to the base station BS1, the busy communication of the base station BS1 is performed even after performing the first high traffic distribution and the second high traffic distribution. The number of channels is still four.

Since there is no remaining usable communication channel, the base station BS1 sets the mobile station M waiting for the base station.
The base station busy is notified to S5. When the mobile station MS5 receives the notification, the mobile station MS5 enters a call-disabled waiting state, and displays the base station busy on the display.

When the mobile station MS1 ends the call, the mobile station MS1
Is released from the communication channel of the base station BS1 that has been used. The number of used communication channels of the base station BS1 is 3,
Since there was a usable communication channel again, the base station BS
1 to notify the base station ready to the outgoing call waiting mobile station MS5. When the mobile station MS5 receives the notification, the mobile station MS5 enters a call waiting state, and turns off the base station busy display on the display.

The embodiments of the present invention have been described above. However, the present invention is not limited to this, and the base station transmits information (traffic, frequency Etc.). When a base station having high traffic is the first high traffic distribution means and issues a handover instruction due to high traffic to a mobile station during a call to the base station, information on other base stations (frequency, etc.) having low traffic is also sent to the mobile station. To instruct. The mobile station can complete the handover operation quickly by directly scanning the other base station having the specified low traffic.

Also, when the base station having a high traffic uses the second high traffic distribution means to instruct the mobile station waiting for the base station to locate another base station having a low traffic, the other base station having a low traffic is transmitted to the mobile station. Information (frequency, etc.)
May also be instructed. The mobile station scans the other base station that has the low traffic directly instructed, so that the operation in the other base station can be completed quickly.

[0046]

According to the present invention described above, traffic can be distributed. The reason is that, when the traffic of the base station exceeds the threshold value, the mobile station during a call of the base station, which is located in a wireless area overlapping with another base station with low traffic, is handed over to another base station. Further, if the traffic of the base station exceeds the threshold value, the mobile station waiting for the base station, which is located in a wireless area overlapping with another base station with low traffic, is located in another base station.

According to the present invention, control channel congestion can be prevented. The reason is that, when the base station becomes busy, it does not allow the waiting mobile station to make a call.

Further, according to the present invention, a user of a mobile station can obtain base station busy information. The reason is that the base station busy information can be displayed on the display of the mobile station.

[Brief description of the drawings]

FIG. 1 is a block diagram of the present invention.

FIG. 2 is an operation flowchart of the present invention.

FIG. 3 is a handover sequence to another base station.

FIG. 4 is a layout diagram of a base station mobile station according to an embodiment;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base station 2 Mobile station 11 1st high traffic detection means 12, 21 1st high traffic distribution means 13 2nd high traffic detection means 14, 22 2nd high traffic distribution means 15 Base station busy detection means 16 Base station busy notification means 23 Base station busy response means

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04Q ^7/ 00-7/38

Claims (1)

(57) [Claims] A base station and a wireless area of the base station overlap each other.
Mobile consisting of multiple adjacent base stations and multiple mobile stations
A traffic distribution method for a mobile communication system, wherein calls are concentrated on said base station in advance.
The number of used communication channels of the base station.
First thresholdAnd calls that remain concentrated at the base station
Indicating that there are very few available communication channels
A second threshold for the number of used communication channels of a base station.
Value and are set,  The base station determines the number of used communication channels of the base station.
Monitoring, the number of used communication channels exceeds a first threshold
Handover to all active mobile stations of the base station.
The mobile station receiving the instruction performs a mobile station search and checks the connection-target base station.
And is located in an adjacent base station area where the wireless area of the base station overlaps.
The in-call mobile station receiving the placed instruction is
Handover to the base station to continue the call, and rank in the adjacent base station area where the base station radio area overlaps
A mobile station receiving a call that has not been placed
Call with the original base station without handoverAnd Thereafter, the base station continues to communicate with the base station in use.
Monitor the number of communication channels, The number of busy communication channels exceeds a second threshold
In this case, another base station shall
Instructed to stay in the local office, The receiving mobile station receiving the instruction sets the connection destination base station to
Investigate, In the adjacent base station area where the wireless area of the base station overlaps
The waiting mobile station receiving the placed instruction
Move to the base station and continue waiting, In the adjacent base station area where the wireless area of the base station overlaps
The waiting mobile station, which has received an instruction that is not placed,
Continue waiting with the original base station without moving to the base station To do
Traffic distribution method characterized by the above-mentioned.