KR101017456B1 - Overload control method and device for failure recovery of mobile communication system - Google Patents

Abstract

The present invention relates to a control processing method and apparatus for preparing for congestion and overload in a mobile communication system.

According to the present invention, a method for processing an overload control during a fault recovery in a mobile communication system, the method comprising: (a) completing recovery after a failure in a core network of the mobile communication system; (b) transmitting an overload control signal from the core network to a base station controller; And (c) the base station controller to limit the connection of the terminal to the base station accommodated in accordance with the received overload control signal; includes an overload control method for recovering a failure of a mobile communication system.

Fault recovery, overload control, core network, call inflow

Description

Method and apparatus for overload control when recovering from a failure in a mobile communication system

The present invention relates to a method for controlling access control and call processing in a mobile communication system, and more particularly, to a control processing method and apparatus in preparation for call congestion and overload occurring in a mobile communication system.

The mobile communication system includes a mobile switching center (MSC), a base station controller (BSC, RNC), a base station (BTS, Node B) mobile communication terminal (MS) and the like. A mobile switch is a core network element of a mobile communication network. It controls voice calls and various additional services, establishes a call path, and provides a connection function with various other devices and external networks. That is, the mobile switch is a switch that provides a circuit switching service and a call channel switching function to a mobile subscriber.

The base station controller is classified into BSC in 2G, RNC in 3G, etc., and manages several base stations and interworks with mobile exchanges, and some provide interworking functions with PDSN and SGSN for 2G, 2.5G, and 3G data services. A base station is classified into a BTS in 2G and a Node B in 3G. The base station is connected to a mobile communication terminal and a wireless section to control mobile communication and connect a call channel.

In general, when a call establishment request is received from a subscriber such as a mobile communication subscriber or a public switched telephone network (PSTN), the mobile communication system allocates resources of the mobile communication system such as allocating a channel for call setup and forms a call. Provide communication services. As such, when an outgoing call, an incoming call, a handoff call, etc. are generated from the mobile communication terminal, the base station transmits a processing request for the call to the mobile exchange through the base station controller. The mobile exchange receives the call processing request and performs the call processing.

In the call processing method of the conventional mobile communication system, when an outgoing signal is generated from the mobile communication terminal, a call setup request is transmitted from the base station to the mobile switch through the base station controller. The mobile exchange allocates one of the multiple traffic channels to set up the call and sends a response to the call setup to the base station.

If such call processing is congested or if the equipment of the core network fails, the system may fail. When such a failure occurs, the system may have a problem such as stopping service provision or disrupting service provision. When a failure occurs in the core network of the mobile communication system, the various services and processes are stopped and a disaster recovery operation is performed. When all system failures are recovered, the system is restarted and the system is operating normally.

However, when the recovery is completed after a failure of the core network, a large number of instantaneous incoming calls cause network overload, thereby causing a second system failure.

That is, when the core network is normally restored and the call processing is possible, the location registration, the incoming / outgoing call, etc., which flow in at the same time, suddenly explode. Such instantaneous call processing causes a recurrence of the overload of the core network, causing a failure, or another service failure due to the overload control procedure.

SUMMARY OF THE INVENTION The present invention has been made to solve this problem, and an object of the present invention is to provide a method and apparatus for controlling a large number of call inflows occurring momentarily upon completion of recovery after a failure of a mobile communication system.

Further objects and advantages of the present invention can be understood by the following description, and will be more clearly understood by the embodiments of the present invention. Also, it will be readily appreciated that the objects and advantages of the present invention may be realized by the means and combinations thereof indicated in the claims.

In order to achieve the above object, the overload control method for fault recovery of a mobile communication system according to the present invention is a method for handling overload control during fault recovery in a mobile communication system, and (a) a fault in a core network of a mobile communication system. Completing recovery after occurrence; (b) transmitting an overload control signal from the core network to a base station controller; And (c) the base station controller to limit the access of the terminal to the receiving base station according to the received overload control signal.

According to another aspect of the present invention, an apparatus for performing an overload control process in the failure recovery in a mobile communication system, comprising: failure recovery notification means for notifying completion of recovery after a failure in a core network of the mobile communication system; And an overload control means for generating an overload control message and transmitting to the base station controller to limit the access of the terminal to the base station accommodated by the base station controller when the recovery completion signal is received by the failure recovery notification means. An overload control device is provided for failure recovery of a communication system.

According to the present invention, upon completion of the failure recovery in the mobile communication system, a message is transmitted to control the amount of the call flowing from the core network to the base station controller, thereby adjusting the amount of the call flowing from the base station controller to the core network. It provides the effect of preventing the general runaway.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the specification and claims should not be construed as having a conventional or dictionary meaning, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention. Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention and do not represent all of the technical idea of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.

1 is a diagram illustrating a configuration of a mobile communication system in which the present invention is implemented.

Referring to FIG. 1, a mobile communication system according to the present invention includes a user equipment (UE), a wireless access network (AN), a core network (CN), an external network (EN), and the like.

The user device comprises a wireless mobile communication terminal 11 which interfaces with a user and is used for wireless communication via a Uu interface. The mobile communication terminal 11 corresponds to a mobile communication terminal such as a cellular phone, a notebook equipped with a wireless modem, and a personal digital assistant (PDA). In addition, the base station 22 of the wireless access network is connected to perform wireless communication and receives broadcast information (system information) through a broadcast channel.

The radio access network deals with radio related functions and a mobile communication terminal and a radio connection, and includes a base station 22 and a base station controller 21. The base station controller 21 is connected to the core network and controls a plurality of lower base stations 22. In addition, broadcast information is provided to the lower base stations 22. The broadcast information is generated and provided in a system information block (SIB) unit. The base station 22 is connected to the base station controller 21 and performs wireless communication with the mobile communication terminals 11 included in a cell unit having a predetermined range, and broadcasts the received broadcast information.

The core network serves to respond to circuit switched and packet switched services, routing requests, and data connections with an external network, and includes a circuit switched station 31, a switched gateway 34, a packet switched station 32, and a packet switched gateway. 35), home position register 33 and overload control device 100, and the like. The circuit switched station 31 performs a circuit switched (CS) service and the switching center gateway 34 performs a switch function at a point connected to an external circuit switched network. The packet switching station 32 performs a packet switching (PS) service, and the packet switching station gateway 35 performs a serving node function at a point connected to an external packet switching network. The home location register 33 is a database located in the user home system that stores the master copy of the user service profile.

The overload control device 100 serves to control the overload by a call that is instantaneously introduced when the core network recovers after a failure or when the system is restarted. In the drawing, the overload control device 100 is illustrated as a separate node device, but the present invention is not limited thereto and may be mounted on any node of the core network. That is, it can be mounted together with the circuit-switching station 31, the packet-switching station 32, etc. to perform a function. A more detailed description of the overload control device 100 will be described later with reference to the drawings.

The external network is composed of an external circuit switched network 41, an external packet network 42 and the like. The external circuit switched network 41 is an external network that provides circuit switched connections. Examples of the external circuit switched network 41 include ISDN, PSTN, and the like. The external packet network 42 is an external data network that provides a packet data service. The external packet network 42 may be the Internet.

2 is a diagram illustrating a configuration of an overload control apparatus for failure recovery of a mobile communication system according to an exemplary embodiment of the present invention.

2, the overload control device 100 according to the present invention includes a failure recovery notification means 110 and the overload control means 120 and the like.

The failure recovery notification unit 110 serves to notify completion of recovery after a failure occurs in the core network of the mobile communication system. That is, the failure occurred in the core network is recovered and serves to inform the completion of the recovery when the core network operates normally. In addition, it can be used as a criterion for notifying the completion of recovery when the power source is applied to the core network to start startup. The failure recovery notification unit 110 may automatically detect the time point when failure recovery is completed after the failure of the core network, and determine the completion point of failure recovery, and the administrator or operator completes the recovery after failure recovery. By providing a signal, this time can be determined as the time to complete the failover. Furthermore, since the power is cut off to each device in the core network during failure recovery, the time point at which power is applied to each device in the core network after completion of recovery may be determined as the completion time of recovery.

The overload control unit 120 receives a failure recovery completion signal from the failure recovery notification unit 110 and performs an overload control process. The overload control unit 120 transmits an overload control signal to the base station controller 21 of the wireless access network to control access and access of the base station 22 and the mobile communication terminal 11. The overload control means 120 includes a message generator 121, a message transmitter 122, a message controller 123, and the like.

The message generator 121 serves to generate an overload control message. The overload control message is a message transmitted to a base station controller of a wireless access network by a protocol and is a message for controlling broadcast information generated and broadcast by the base station controller. The overload control message may use, for example, a Radio Access Network Application Part (RANAP) overload message.

When the overload control message is generated through the message generator 121, the message transmitter 122 transmits the message to the base station controller. The message transmitter 122 controls the message transmission cycle and the transmission target according to the message controller 123 which will be described later.

The message controller 123 controls the message generator 121 and the message transmitter 122. The message controller 123 defines various parameters included in a message when the message generator 121 generates an overload control message. In addition, it controls to periodically transmit the message generated by the message transmitter 122, and also controls the time interval of the transmission period.

For example, a number of steps may be defined in an overload message, and a time interval for transmitting the message may be set to transmit a periodically generated message. The step value is a value that classifies the degree of access restriction of the terminals, and allows the access permission rate or the call permission rate to be changed step by step. Preferably, the message control unit 123 defines and transmits a step value so that the most call allowance rate is low when generating an overload message with failure recovery, and gradually increases the call allowance rate when the message is retransmitted at regular intervals. Define the step value to increase and control to send. In such a control, since the amount of call processing flowing into the core network gradually increases after failing over, failure reoccurrence due to instant call congestion can be prevented.

3 is a flowchart illustrating a procedure of an overload control method for each node of a mobile communication system according to an embodiment of the present invention for each node.

Referring to FIG. 3, the procedure of the overload control method according to the present invention will be described. First, when a failure occurs in the core network, a procedure of restoring the overload control method is started.

When the failure recovery is completed, a procedure of generating an overload control message to be transmitted to the base station controller is performed. The overload control message generated at this time is set to gradually relax the call admission and the terminal access restriction over time (S12).

When the overload control message is generated, a procedure of transmitting the overload control message to the base station controller of the radio access network is performed. The message transmitted here may be, for example, a WCDMA RANAP overload message (S13).

In the base station controller of the wireless access network, a procedure for receiving an overload control message is performed.

When the overload control message is received, a procedure of analyzing the message and setting broadcast information according to the control instruction is performed. That is, the overload control signal is set to limit the access or access of the terminal to the broadcast information message. In addition, the broadcast information message may be an example of a system information block (SIB) message of WCDMA. In more detail, the SIB # 3 message is used and the access control information item (Cell Access Restriction IE) in the message is configured to restrict access of the terminal.

When the broadcast information message is generated in this way, the base station controller performs a procedure of broadcasting to the mobile communication terminal located in the corresponding cell through the base station accommodating it. Such broadcast information is broadcasted through a broadcast channel of the mobile communication system (S23).

The mobile communication terminal located in the cell of the base station receives broadcast information. This broadcast information includes overload control information provided from the core network (S31).

The mobile communication terminal analyzes the received broadcast information and proceeds to block access to the wireless access network according to the overload control information included in the broadcast information. The overload control information includes a control signal and a blocking ratio information for allowing the terminal to block access to the wireless access network.

As the access of the mobile communication terminal is blocked in the base station controller, call processing and access of the terminal are restricted. At this time, access of all terminals is not limited, but access is restricted according to a predetermined ratio according to the overload control information.

As the access and call processing of the terminal is restricted in the base station controller, the incoming call is blocked in the core network. At this time, too, call inflow and call allowance are determined according to the ratio.

In addition, the procedure from step S13 to step S14 continues continuously at predetermined intervals. Through such periodic control, it is possible to gradually control the access restriction of the terminal so that the call flowing into the core network can be smoothly introduced over time.

4 is a diagram illustrating an algorithm of a method for controlling overload during failure recovery according to an embodiment of the present invention.

Referring to Figure 4, first, the failure recovery is completed in the core network (S1).

Next, set the time when the failover is completed to 0 seconds 'n = 0' (S2).

In addition, the overload message is transmitted from the core network to the base station controller. At this time, the step value (Number of Step) of the overload message is set to '16 -n '(S3).

The base station controller sets broadcast information, that is, cell access restriction information item of SIB # 3 to one of access classes 0 to 9 according to the received overload message. The base station controller sets the access restriction according to the amount of the ratio corresponding to the set access level for all base stations accommodated, and transmits it to the terminal. The terminal set as the access restriction for the corresponding access class is unable to access the base station, and can control the incoming call to the core network. In addition, when setting the access restriction ratio to the broadcast information, the step value (16-n * S) is extracted from the message received in step S3 and substituted into [[16-n * S) / 16] * 100 '. To derive the percentage and set it as the access restriction rate. In the above example, the initial failure recovery has a step value of 16-0 at n = 0, so the access restriction ratio is [(16-0) / 16] * 100, resulting in 100 percent. That is, access class restriction processing is performed for all base stations (S4).

Next, as time elapses, the time variable increases to 'n = n + 1'. That is, one second elapses (S5).

After the time elapses, a procedure of determining whether the condition '16 -n> 0 'is satisfied is performed. If it is satisfied, the process proceeds to step S3 for continuously transmitting an overload message. If not, the process proceeds to step S7. That is, the above steps are repeated until 16 seconds have elapsed. Since 1 second has elapsed in step S5, the condition '16 -1> 0 'is satisfied and the process proceeds to step S3.

Since 1 second has elapsed, the step value becomes 16-1 when n = 1 in the overload message. The base station controller receiving this value calculates '[(16-1) / 16] * 100' to obtain 93.75 percent. That is, access class restriction processing is performed for 93.75 percent of base stations. As such, access rate restrictions will gradually decrease until 16 seconds have elapsed. As a result, the rate of call inflow into the core network is gradually increased.

Next, when 16 seconds, i.e., a predetermined time elapses, in step S6, all calls are allowed to enter, and accordingly, a procedure of stopping transmission of an overload message is performed.

FIG. 5 is a diagram illustrating a graph in which an incoming call gradually increases over time by an overload control algorithm according to the present invention.

As shown in the figure, call ingress was blocked 100 percent after completion of failover in the first core network, but as time passed (N, 2 * N, 3 * N, etc.) After the time elapses, the call is allowed. By controlling the incremental call admission to the core network in this way, it is possible to solve the problem of overload due to instant call congestion and failure reoccurrence.

6 is a diagram illustrating an example of a RANAP overload message transmitted from a core network to a base station controller.

As shown in the figure, an overload message is transmitted to the base station controller by setting a step value in the 'Number of Steps' information item.

7 is a diagram illustrating an example of a system information block type 3 message generated by a base station controller. 8 is a diagram illustrating an example of a cell access restriction information item in a SIB # 3 message.

As shown in Fig. 7 to 8, the base station controller receives the overload message and according to the control information contained therein. Reflecting this in the Cell Access Restriction information item in the SIB # 3 message, an 'Access Class Barred List' is set, and then broadcasted to mobile terminals through a base station.

Although the present invention has been described above by means of limited embodiments and drawings, the present invention is not limited thereto and will be described below by the person skilled in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of the claims.

The following drawings, which are attached to this specification, illustrate exemplary embodiments of the present invention, and together with the detailed description of the present invention serve to further understand the technical spirit of the present invention, the present invention includes matters described in such drawings. It should not be construed as limited to.

1 is a diagram illustrating a configuration of a mobile communication system in which the present invention is implemented.

2 is a diagram illustrating a configuration of an overload control apparatus for failure recovery of a mobile communication system according to an exemplary embodiment of the present invention.

3 is a flowchart illustrating a procedure of an overload control method for each node of a mobile communication system according to an embodiment of the present invention for each node.

4 is a diagram illustrating an algorithm of a method for controlling overload during failure recovery according to an embodiment of the present invention.

5 is a diagram showing a graph in which the incoming call gradually increases over time due to the overload control algorithm according to the present invention.

6 is a diagram illustrating an example of a RANAP overload message transmitted from a core network to a base station controller.

7 is a diagram illustrating an example of a system information block type 3 message generated by a base station controller.

8 is a diagram illustrating an example of a cell access restriction information item in a SIB # 3 message.

<Explanation of symbols for the main parts of the drawings>

11: mobile communication terminal 21: base station controller

22: base station 31: switching center

32: packet switching station 33: home location register

34: switching center gateway 35: packet switching gateway

Claims (14)

As a method of handling overload control when recovering from a failure in a mobile communication system, (a) completing recovery after a failure in the core network of the mobile communication system; (b) transmitting an overload control signal from the core network to a base station controller upon failure recovery completion; And (C) the base station controller to limit the connection of the terminal to the base station accommodated in accordance with the received overload control signal; overload control method during the failure recovery of a mobile communication system comprising a. The method of claim 1, Step (c) is, The base station controller is configured to limit the access of the terminal to the broadcast information message according to the received overload control signal to broadcast to the terminal through the base station, overload control method for the failure recovery of the mobile communication system. The method according to claim 1 or 2, The overload control signal is an overload control method for fault recovery of a mobile communication system, characterized in that the control signal to gradually relax the restriction over time. The method according to claim 1 or 2, In step (a), When the failover completes, An overload control method for recovering from a failure of a mobile communication system, wherein the failure occurred in the core network is restored, and the core network operates normally or when the power is applied to the core network. The method according to claim 1 or 2, In step (b), The overload control signal is periodically transmitted at predetermined time intervals. The method of claim 5, The overload control signal is configured to relax the restrictions step by step every time the transmission is overload control method for the failure recovery of the mobile communication system. The method according to claim 1 or 2, In step (b), The overload control signal is included in a RANAP (Radio Access Network Application Part) overload message and transmitted, overload control method for the failure recovery of a mobile communication system. The method of claim 2, The broadcast information message is a SIB # 3 (System Information Block Type 3) message and is configured to restrict access of a terminal to a cell access restriction information item (Cell Access Restriction IE) in the message. Overload control method. An apparatus for performing an overload control process when recovering from a failure in a mobile communication system, Failure recovery notification means for indicating completion of recovery after a failure in the core network of the mobile communication system; And And an overload control means for generating an overload control message and transmitting the control completion signal to the base station controller to limit the access of the terminal to the base station accommodated by the base station controller. Overload control device in case of system failure recovery. The method of claim 9, The overload control means is set to gradually relax the restriction over time to generate an overload control message, characterized in that the overload control device in the failure recovery of the mobile communication system. 11. The method according to claim 9 or 10, The overload control means, A message generator for receiving a recovery completion signal and generating an overload control message; A message transmitter for transmitting an overload control message generated to a base station controller; And Overload control device for failure recovery of a mobile communication system comprising a; message control unit for controlling the setting and generation period of the generated message. The method of claim 10, The message control unit, the overload control device for failure recovery of the mobile communication system to control to generate and transmit a message periodically at predetermined time intervals. 13. The method of claim 12, The message control unit is configured to control the generation of the message by overloading each time a message is generated periodically, thereby generating a message. 11. The method according to claim 9 or 10, The disaster recovery notification means, An overload control apparatus for recovering a failure of a mobile communication system, wherein the failure of the core network is recovered and the recovery completion is notified based on a time point when the core network operates normally or when the power is applied to the core network to start up.

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