KR100443173B1 - The Method of Overload Control for Cell Broadcast Service - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

The present invention relates to an overload control method for a cell broadcast service in a mobile communication system and a computer-readable recording medium having recorded thereon a program for realizing the method.

2. The technical problem to be solved by the invention

An object of the present invention is to provide an overload control method for effectively controlling an overload condition generated during a cell broadcast service by adjusting a radio resource and a broadcast period, and a computer-readable recording medium recording a program for realizing the method.

3. Summary of Solution to Invention

According to an aspect of the present invention, there is provided a method for controlling an overload in a control station in a mobile communication system, the method comprising: a first overload state control step of additionally allocating a radio resource in a control station when recognizing an overload condition due to insufficient radio resources in a cell broadcast service; A second overload state control step of transitioning to an overload state and notifying the cell broadcast center that an overload has occurred, so that an additional broadcast request is not generated from the cell broadcast center if it is impossible to allocate an additional radio resource; In the overload condition, if additional broadcast request from the cell broadcast center is continuously received, the control station may determine the priority according to the 'priority based on the broadcast period, broadcast period and message size of the broadcast message currently being broadcast'. Broadcast by increasing the broadcast cycle of the broadcast message step by step, and when the radio resources are available as the broadcast of the currently broadcast message is gradually completed, the 'broadcast period of the broadcast message with increased broadcast cycle' according to the priority A third overload condition control step of restoring stepwise to restore the original condition; And an overload state canceling step of transitioning the overload state to the released state when the broadcast period for all the broadcast messages is restored to the original state and notifying the cell broadcast center that the overload state has been released.

4. Important uses of the invention

The present invention is used for overload control of cell broadcast service in a mobile communication system.

Description

Overload control method for cell broadcast service in mobile communication system

The present invention relates to the technical field related to cell broadcast services, and more particularly, to a cell broadcast service (CBS) in a control station (RNC: Radio Network Controller) of an asynchronous IMT-2000 (International Mobile Telecommunication-2000) system. The present invention relates to a method for effectively controlling an overload generated during provision and a computer-readable recording medium having recorded thereon a program for realizing the method.

Currently, a cell broadcast service is a service that periodically broadcasts a specific broadcast message in a service area composed of several cells, that is, a base station, for a predetermined period of time, and the terminal transmits various types of broadcast messages broadcasted to the base station where the terminal is located. Can be selectively received. Cell broadcast services are allocated radio resources of limited capacity. That is, the cell broadcast message is transmitted by being allocated a logical channel called a common traffic channel (CTCH) in a radio section. Here, the common traffic channel, which is a logical channel, corresponds to a transport channel called a forward access channel (FACH), and the forward transport channel is a secondary common control physical channel (S-CCPCH). The cell broadcast service is provided through the corresponding physical channel.

However, in providing a cell broadcast service, there is a problem of exceeding a capacity of a radio resource. Thus, as a method for efficiently using radio resources in the prior art, there is a "broadcasting service method (Korea Patent Registration No. 10-20001-0038059, registered on 15 May 2001), which is a mobile communication system. In order to provide a common broadcast service to a plurality of users located in an arbitrary cell through the same call channel.

The prior art uses a common call channel as a form of a channel used for cell broadcasting, so that it is easy to implement and saves radio resources, but does not mention a case where radio resources are exceeded in cell broadcasting services.

In addition, in the prior art, in order to solve the problem of overload as described above, when providing a cell broadcast service, when a control station recognizes an overload condition, that is, when the cell broadcast service exceeds a limited capacity of radio resources, Although the overload was controlled by additional allocation of necessary radio resources, the overload status of the control station was not notified to the cell broadcast center (CBC), which is a network element that directly requests cell broadcasting. Only when the cell broadcast center requests available radio resources from the control station for cell broadcast service has been found indirectly that the radio resources are overloaded.

Thus, since the prior art does not accurately notify the cell broadcast center of the occurrence of an overload condition at the control station, the overload control should be solved by itself within the control station first, especially when the allocation of additional radio resources is impossible. If a new broadcast request from the center continues to be received, a service interruption state in which the cell broadcast service is partially suspended or the new broadcast request is rejected occurs is a problem for stable performance of the cell broadcast service.

The present invention has been proposed to solve the above problems, and an overload control method for effectively controlling an overload condition generated during a cell broadcast service by adjusting radio resources and a broadcast period, and a program for realizing the method. Its purpose is to provide a computer-readable recording medium for recording.

1 is an exemplary configuration diagram of a cell broadcast service system to which the present invention is applied.

FIG. 2 is a diagram illustrating a protocol stack structure for cell broadcast service in FIG.

3 is a flowchart illustrating a signal processing procedure between a control station and a cell broadcast center when an overload condition occurs during a cell broadcast service according to the present invention.

4 is a flow diagram of one embodiment of an overload control method at a control station based on the signal flow of FIG. 3 in accordance with the present invention;

* Explanation of symbols for the main parts of the drawings

10: terminal 11: base station

12 control station 13 cell broadcasting center

14: cell broadcast entity

In order to achieve the above object, the present invention provides a method for overload control in a control station in a mobile communication system. 1 overload condition control step; A second overload state control step of transitioning to an overload state and notifying the cell broadcast center that an overload has occurred, so that an additional broadcast request is not generated from the cell broadcast center if it is impossible to allocate an additional radio resource; In the overload condition, if additional broadcast request from the cell broadcast center is continuously received, the control station may determine the priority according to the 'priority based on the broadcast period, broadcast period and message size of the broadcast message currently being broadcast'. Broadcast by increasing the broadcast cycle of the broadcast message step by step, and when the radio resources are available as the broadcast of the currently broadcast message is gradually completed, the 'broadcast period of the broadcast message with increased broadcast cycle' according to the priority A third overload condition control step of restoring stepwise to restore the original condition; And an overload state releasing step of transitioning the overload state to the released state and informing the cell broadcast center that the overload state has been released.

Meanwhile, the present invention provides a mobile communication system having a processor for overload control of a cell broadcast service, and additionally allocates a radio resource within a control station when it recognizes that the cell resource is overloaded due to a lack of radio resources. Overload condition control function; A second overload state control function for transitioning to an overload state and notifying the cell broadcast center that an overload has occurred, so that an additional broadcast request is not generated from the cell broadcast center if it is impossible to allocate an additional radio resource; In the overload condition, if additional broadcast request from the cell broadcast center is continuously received, the control station may determine the priority according to the 'priority based on the broadcast period, broadcast period and message size of the broadcast message currently being broadcast'. Broadcast by increasing the broadcast cycle of the broadcast message step by step, and when the radio resources are available as the broadcast of the currently broadcast message is gradually completed, the 'broadcast period of the broadcast message with increased broadcast cycle' according to the priority A third overload condition control function to reduce the phase by step and restore it to its original state; And when the broadcast cycle for all broadcast messages is restored to its original state, a program for transitioning the overload state to the released state and realizing an overload state release function for notifying the cell broadcast center that the overload state has been released can be read by a computer. Provide a recording medium.

In order to effectively control the overload generated during the cell broadcast service at the control station of the asynchronous IMT-2000 system, the present invention notifies the cell broadcast center of an overload condition when additional allocation of radio resources for the cell broadcast service is impossible. The new broadcast request is prevented from being made, and the overload condition is controlled by adjusting the broadcast period of the individual broadcast message according to the priority based on the broadcast period, the broadcast period, and the size of the broadcast message. The present invention relates to an overload control method for a cell broadcast service in a control station of an asynchronous mobile communication system. When the control station determines that an overload condition occurs during cell broadcast scheduling, it requests an additional allocation of radio resources for the cell broadcast service. If additional radio resources cannot be allocated In one case, the overload control is effectively performed while minimizing the effect on the cell broadcast service by increasing the broadcast period step by step according to the broadcasting period, broadcast period, and message size of the currently broadcast cell broadcast messages. In the present invention, when the control station recognizes an overload condition, the present invention first resolves the overload condition by additional allocation of radio resources, and when an additional allocation of radio resources is impossible, an additional broadcast request is generated by notifying the cell broadcasting center that the overload condition is not possible. In this state, if additional broadcast request is continuously received from the cell broadcast center, the control station adjusts the broadcast period according to the priority based on the broadcast period, broadcast period, and message size of the broadcast message currently being broadcast. Effectively eliminates overload conditions Can.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram illustrating a configuration of a cell broadcast service system to which the present invention is applied, and particularly illustrates an asynchronous IMT-2000 system for cell broadcast service.

As shown in FIG. 1, a cell broadcast service system to which the present invention is applied includes a plurality of cell broadcast entities (CBEs) 14 and a plurality of cell broadcast entities 14 for providing a cell broadcast service. A cell broadcast center 13 for receiving a cell broadcast service broadcast request and transmitting the cell broadcast request to a control station 12 belonging to a service area, and a base station 11 for receiving a cell broadcast request from the cell broadcast center 13. A control station 12 which transmits a broadcast message to be broadcasted in each unit to each base station 11, and a base station 11 which broadcasts a broadcast message from the control station 12 to the terminal 10. It is done by

The cell broadcast center 13 receives broadcast requests from various cell broadcast entities 14 that are cell broadcast service providers. At this time, one broadcast request is represented by (broadcast message identifier, broadcast period, broadcast period, broadcast area, message content), and the broadcast area is composed of a plurality of base stations (Node B) 11. The cell broadcast center 13 transmits this cell broadcast request to the control station 12 controlling the base station 11 belonging to the service area.

Subsequently, the control station 12 classifies the broadcast request transmitted from the cell broadcast center 13 into units of the base station 11 controlled by the control station 12, and broadcasts the broadcast messages to be broadcast from each base station 11. It transmits to the base station 11 according to the requested period during the broadcast period requested from (13).

Next, the base station 11 broadcasts the broadcast message received from the control station 12 through the air interface.

Finally, the user equipment (UE) 10 selects and receives a cell broadcast message received from a cell in which it is located by type.

FIG. 2 is a diagram illustrating a protocol stack for cell broadcast service in FIG.

Referring to Figure 2 describes the protocol structure as follows.

First, a cell broadcast request from the cell broadcast center 13 to the control station 12 is made by a service area broadcast protocol (SABP) layer 26, and the cell broadcast is performed by the SABP layer 22 of the control station 12. The broadcast request requested from the center 13 is delivered to the BMC (Broadcast and Multicast Control) layer 21.

Thereafter, the BMC layer 21 schedules various broadcast requests received from the SABP layer 22 in units of the base station 11 according to the broadcast period, the broadcast period, and the message size, and instructs the corresponding base station 11 to broadcast.

At this time, the radio resource control (RRC) layer 20 of the control station 12 functions to allocate radio resources necessary for cell broadcast service, and the radio resources are RLC (Radio Link Control) layer 23 and MAC (Medium). Access Control) layer 24, and Radio layer 25 is supported.

In addition, the BMC layer 21 may predict the amount of radio resources currently required in the scheduling process, and when the resources are insufficient, notify the RRC layer 20 to request allocation of additional radio resources.

3 is a flowchart illustrating a signal processing procedure between a control station and a cell broadcast center when an overload condition occurs during a cell broadcast service according to the present invention.

First, when the cell broadcast center 13 transmits a message " WRITE-REPLACE " to the control station 12 and requests broadcasting of a new message (31), the control station 12 responds to the " WRITE-REPLACE COMPLETE " Message is transmitted to the cell broadcast center 13 (32). Then, the control station 12 determines the occurrence of an overload condition, and performs overload control by additional allocation of radio resources (resolves an overload condition). In this case, if it is impossible to allocate additional radio resources, the control station 12 transmits an "OVERLOAD INDICATION" message to the cell broadcast center 13, indicating that the control station 12 is overloaded. By informing, the cell broadcast center 13 instructs 33 to refrain from further broadcast requests. However, when a new broadcast request is transmitted from the cell broadcast center 13 to the control station 12 through the " WRITE-REPLACE " message during the overload state (34), the broadcast period, the broadcast period and the broadcast of the broadcast message currently being broadcast. The broadcast period of the individual broadcast message is gradually increased according to the priority based on the size of the message, and the broadcast is sent to the cell broadcast center 13 (35). In other words, the control station 12 sends a " WRITE-REPLACE COMPLETE " message. Recognizing that an overload condition is detected, first, the overload condition is solved by additional allocation of radio resources, and when the additional allocation of radio resources is impossible, the cell broadcasting center 13 is notified that the overload condition is not generated so that no additional broadcast request is generated. In this state, if additional broadcast request is continuously received from the cell broadcast center 13, the control station 12 broadcasts the broadcast message of the currently broadcasted message. In this case, the overload condition can be effectively controlled by adjusting the broadcast period according to the broadcast period and the priority based on the message size. As the broadcast of the currently broadcasted message is gradually completed, when the radio resource becomes available, the broadcast period is Control overload conditions by restoring broadcast periods incrementally for increased broadcast messages. If the broadcast period for all broadcast messages has been restored, the control station 12 transitions to the overload release state, and the cell broadcast center (overload state = "false") message indicates that the overload state has been released. 13) (36).

4 is a flow diagram of an embodiment of an overload control method at a control station based on the signal flow of FIG. 3 in accordance with the present invention.

First, when the BMC layer 21 of the control station 12 recognizes the possibility of an overload condition due to lack of radio resources in the process of performing cell broadcast scheduling (40), the RRC layer 20 of the control station 12 Request additional allocation of radio resources (41). In contrast, when the RRC layer 20 of the control station approves allocation of additional radio resources for the cell broadcast service (42), the radio station allocates additional radio resources to perform the cell broadcast service. In step 43, the overload state flag is set to "true" (43), and the cell broadcast center 13 is notified of the overload state (44).

On the other hand, when receiving a new broadcast request from the cell broadcast center 13 (45), the control station 12 refers to the overload state flag if it is overloaded (overload state = "true") 46 and the current control station ( The overload is controlled by increasing the broadcast period for each message step by step according to the priority based on the broadcast period, the broadcast period, and the size of the broadcast message in step 12).

On the other hand, when the broadcast for a specific broadcast message is completed in the overload state (48), the control station 12 refers to the overload state flag if the overload state (overload state = "true") (49) the message currently being broadcasted The broadcast period is gradually reduced according to the priority based on the broadcast period, the broadcast period, and the size of the broadcast message to restore the original condition (50). If the broadcast period for all the broadcast messages currently being broadcast is restored (51), the overload state flag is set to "false" (overload state = "false") and the state transitions to the overload release state (52). The broadcast center 13 is notified that the overload condition is released (53).

As described above, the overload control method in the control station 12 for the cell broadcast service according to the present invention primarily controls the overload state by additional allocation of radio resources, and if the additional allocation of radio resources is impossible, The cell broadcast center 13 is immediately notified that it has been issued to prevent an additional cell broadcast request from occurring, and in response to the determination of an overload condition, an additional broadcast request from the cell broadcast center 13 or a broadcast for a specific broadcast message is prevented. When it is completed, the control station 12 can effectively control the overload by gradually adjusting the broadcast period according to the priority of the broadcast message currently being broadcast.

The method of the present invention as described above may be implemented as a program and stored in a computer-readable recording medium (CD-ROM, RAM, ROM, floppy disk, hard disk, magneto-optical disk, etc.).

The present invention described above is not limited to the above-described embodiment and the accompanying drawings, and it is common in the art that various substitutions, modifications, and changes can be made without departing from the technical spirit of the present invention. It will be evident to those who have knowledge of.

In the present invention as described above, the control station primarily uses an additional allocation method of radio resources in order to control an overload state generated during a cell broadcast service (primary overload state control), in which case additional allocation of radio resources is impossible. By notifying the cell broadcast center that an overload condition has occurred in the control station (secondary overload condition control), the cell broadcast center immediately recognizes that an overload condition has occurred and has an effect of adjusting a broadcast request to the control station.

In particular, the present invention is to broadcast according to the priority of the messages being broadcast when there is a change in the radio resource capacity according to the additional broadcast request from the cell broadcast center or the completion of the broadcast of the existing broadcast message in the control station when the control station is overloaded By adjusting the period (tertiary overload condition control), the cell broadcast service can be continuously and stably performed even under an overload condition, and the new broadcast message request can be accommodated even when a new broadcast message request is received.

Claims (4)

delete In the overload control method at the control station in a mobile communication system, A first overload state control step of additionally allocating a radio resource in the control station if it is recognized that the radio resource is insufficient due to lack of radio resources in the cell broadcast service; A second overload state control step of transitioning to an overload state and notifying the cell broadcast center that an overload has occurred, so that an additional broadcast request is not generated from the cell broadcast center if it is impossible to allocate an additional radio resource; In the overload condition, if additional broadcast request from the cell broadcast center is continuously received, the control station may determine the priority according to the 'priority based on the broadcast period, broadcast period and message size of the broadcast message currently being broadcast'. Broadcast by increasing the broadcast cycle of the broadcast message step by step, and when the radio resources are available as the broadcast of the currently broadcast message is gradually completed, the 'broadcast period of the broadcast message with increased broadcast cycle' according to the priority A third overload condition control step of restoring stepwise to restore the original condition; And When the broadcast period for all broadcast messages is restored to its original state, the overload state is shifted to the released state, and the overload state canceling step of notifying the cell broadcast center that the overload state is released. Overload control method for a cell broadcast service in a mobile communication system comprising a. The method of claim 2, The first to third overload state control step, In order to control the overload condition due to lack of radio resources, the cell may be controlled by additional resource allocation inside the control station, notification of the overload state to the cell broadcasting center, and adjustment of a broadcast period of a broadcast message currently broadcasting inside the control station. An overload control method for a cell broadcast service in a mobile communication system, characterized by controlling overload of a broadcast service. In the mobile communication system having a processor for overload control of cell broadcast service, A first overload state control function for additionally allocating a radio resource in the control station when it is recognized that the overload state is insufficient due to insufficient radio resources in the cell broadcast service; A second overload state control function for transitioning to an overload state and notifying the cell broadcast center that an overload has occurred, so that an additional broadcast request is not generated from the cell broadcast center if it is impossible to allocate an additional radio resource; In the overload condition, if additional broadcast request from the cell broadcast center is continuously received, the control station may determine the priority according to the 'priority based on the broadcast period, broadcast period and message size of the broadcast message currently being broadcast'. Broadcast by increasing the broadcast cycle of the broadcast message step by step, and when the radio resources are available as the broadcast of the currently broadcast message is gradually completed, the 'broadcast period of the broadcast message with increased broadcast cycle' according to the priority A third overload condition control function to reduce the phase by step and restore it to its original state; And When the broadcast period for all broadcast messages is restored to its original state, the overload state is shifted to the released state, and the overload state canceling function notifies the cell broadcasting center that the overload state has been released. A computer-readable recording medium having recorded thereon a program for realizing this.