KR100828544B1 - Device and Method for Controlling Overload - Google Patents

Abstract

The present invention relates to an overload control apparatus and method in a mobile communication system, and more particularly, to an apparatus and method for controlling an overload by controlling an active set for handover. In the mobile communication system, the overload control device includes a load measuring unit measuring load information at a predetermined time, an overload determining unit determining whether an overload occurs by comparing the load information with a preset threshold value, and when the result of the overload occurs An active set for generating a control signal for controlling an active set for handover by using a parameter changer for changing a parameter value for adjusting an active set according to the degree of overload and a parameter corresponding to the degree of overload It may include a setting unit.

Active set, handover

Description

Overload control device and its method {Device and Method for Controlling Overload}

1 is a diagram for explaining soft handover in a conventional mobile communication system.

2 is a view for explaining an overload control device according to an embodiment of the present invention.

3 is a view for explaining the overload control method according to an embodiment of the present invention.

Figure 4 is a block diagram of an overload control device according to an embodiment of the present invention.

5 is a flow chart of the overload control method according to an embodiment of the present invention.

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

110: mobile communication terminal 120, 130, 140: base station

150: base station controller 160, 170, 180: cell

400: overload control unit 410: load measurement unit

420: overload determination unit 430: parameter changing unit

440: active set control unit

The present invention relates to an overload control apparatus and method in a mobile communication system, and more particularly, to an apparatus and method for controlling an overload by controlling an active set for handover.

The mobile communication service has been continuously developed starting from the low-quality voice call-oriented first generation mobile communication service provided by the analog cellular Advanced Mobile Phone Service (AMPS), which has been in service since the late 1980s.

In the second generation mobile communication service, enhanced voice call and low speed (14.4 Kbps) data service provided by digital cellular Global System for Mobile (GSM), Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), etc. are possible. It was.

 In addition, in the 2.5G mobile communication service, the PCS (Personal Communication Service), which can be used around the world in addition to securing the frequency in the GHz band, has been developed to enable improved voice call and low speed (144 Kbps) data service. Mobile communication networks for mobile communication services up to the 2.5th generation include various types of communication such as a user terminal, a base station transmitter, a base station controller, a mobile switching center, a home location register (HLR), and a visitor location register (VLR). The equipment is installed.

The third generation mobile communication service is classified into asynchronous mobile communication system proposed by 3GPP (Generation Partnership Project) and synchronous CDMA-2000 system proposed by 3GPP2. In particular, the mobile communication system is a wireless protocol recommended by IMT-2000, and many communication service providers around the world are providing or preparing to provide services.

Mobile communication systems have a high call quality and use a spread spectrum method, which is suitable for transmitting a large amount of data. The WCDMA communication method adopts AMR (Adaptable Multi-Rate) for voice coding, and supports high mobility enough to make a call even if the user moves at a speed of about 100 Km per hour. In addition, WCDMA communication is adopted by most countries, and 3GPP, which is composed of many organizations such as Korea, Europe, Japan, the United States, and China, is continuously developing technical specifications for WCDMA.

Generally, a service provider or network operator provides various multimedia data and / or voice communication services to different users via a wireless network of the communication system. To provide such data and / or voice communication services, these providers or operators manage radio resources, including system capacity or throughput.

The mobile communication terminal can access the communication system and other interconnected wireless telecommunication systems through one or more base stations. Each area covered by a base station is generally called a cell. Each base station is configured to transmit at a preselected pilot power level sufficient to cover the cell. The pilot channel is broadcast on the downlink to allow cell identification and reception level measurement.

The mobile communication terminal manages communication with a wireless communication system by communicating between one base station and another base station. The mobile wireless terminal can communicate with the nearest base station, the base station with the strongest signal, a base station with sufficient capacity to receive communications, and the like. For example, a mobile communication terminal moves from one cell to another cell and receives a mobile communication service. This cell change or transition process is generally referred to as handover.

1 is a diagram for explaining soft handover in a conventional mobile communication system.

Referring to FIG. 1, when the mobile communication terminal 110 moves a base station (node B) 120, 130, 140, 120 that is occupied after setting up a call, the mobile communication terminal 110 disconnects the call. To ensure no mobility, it occupies the radio links of several base stations (Node B) 120, 130, 140 (130, 140) at the same time to release the radio link with poor radio environment and to add the radio link with good radio environment. Repeat the process. This is called soft handover and guarantees natural mobility of the mobile communication terminal 110.

The mobile communication terminal 110 determines a handover decision from a base station controller (RNC) 150 (Radio Network Control) 150 that controls an area where the mobile communication terminal 110 is located in order to determine whether a handover occurs. Necessary information elements For example, a neighbor cell list, a measurement report range, and hysteresis are transmitted as a radio resource control (RRC) message and a measurement control signal. In addition, the mobile communication terminal 110 measures the cell 120 and the neighbor cell to which the call is set and transmits a cell suitable for the handover condition to the base station controller (RNC) 150 through a measurement report.

The base station controller (RNC) 150 determines whether the current mobile communication terminal 110 should handover with reference to the measurement report message received from the mobile communication terminal 110 and executes handover through the core network CN. do.

In case of performing the above-described conventional handover, the base station (node B) 120, 130, 140 and the base station controller (RNC) 150 only controls the number of calls, incoming calls, location registration, etc., when an overload occurs. The load rates of the base station (Node B) 120, 130, 140 and the base station controller (RNC) 150 by limiting the number of calls flowing into the Node B) 120, 130, 140 and the base station controller (RNC) 150 The overload control was carried out in such a manner as to lower the temperature. However, when the base station (Node B) 120, 130, 140 and the base station controller (RNC) 150 overload occurs, the main processor load ratio increase contribution due to signal processing for handover is caused by the originating call, the incoming call, the location registration, and the like. Since it is higher than the rising contribution, controlling the number of handover occurrences may be more efficient at resolving overload control of the base station (Node B) 120, 130, 140 and base station controller (RNC) 150.

Therefore, an object of the present invention, if the overload control through the control of the number of handover occurs, not only can reduce the effective load rate with a minimum call processing signaling control, but also minimize the deterioration of quality of experience for subscribers In order to control the load ratio of the system in the overload of the mobile communication system efficiently to provide an overload control device and control method for controlling.

Other objects of the present invention will be readily understood through the following description.

According to an aspect of the present invention for achieving the above object, the overload control device in the mobile communication system is a load measuring unit for measuring the load information every predetermined time, whether or not the overload by comparing the load information with a predetermined threshold value An overload judging unit for determining an overload, a parameter change unit for changing a parameter value for adjusting an active set according to the overload degree when the overload occurs, and activation for handover using a parameter corresponding to the overload degree. It may include an active set setting unit for generating a control signal for controlling the set (Active Set).

According to another aspect of the present invention, a method for controlling overload in a mobile communication system includes measuring load information every predetermined time, comparing the load information with a preset threshold, and determining whether an overload has occurred, the determination As a result, when an overload occurs, changing a parameter for adjusting an active set according to the degree of overload and a control signal for controlling an active set for handover corresponding to the degree of overload using the parameter The method may further include generating a hysteresis parameter for the event 1c used when the cell of the active set is replaced or an adjustment parameter for adjusting the number of cells included in the active set.

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. In describing the drawings, similar reference numerals are used for similar elements.

Terms including ordinal numbers such as first and second may be used to describe various components, but the components are not limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component. The term and / or includes a combination of a plurality of related items or any item of a plurality of related items.

When a component is referred to as being "connected" or "connected" to another component, it may be directly connected to or connected to that other component, but it may be understood that other components may be present in between. Should be. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that there is no other component in between.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, and the same or corresponding components will be given the same reference numerals regardless of the reference numerals, and redundant description thereof will be omitted. In the following description of the present invention, if it is determined that the detailed description of the related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

Hereinafter, the present invention can be applied to various mobile communication systems, such as, for example, a second generation communication system, and the following will mainly be described with an example of a WCDMA system.

2 is a view for explaining an overload control device according to an embodiment of the present invention.

The present invention adjusts the frequency of handover by controlling the maximum number of active sets of cells that can be allocated to each mobile communication terminal when the base station (Node B) 120, 130, 140 and the base station controller (RNC) 150 are overloaded. 2, the active set is a radio link of a base station (node B) 120, 130, 140 that the mobile communication terminal occupies during call processing. For example, while the mobile communication terminal 100 moves from the first cell 170 to the second cell 180, the active set is removed in the region where the first cell 170 and the second cell 180 overlap. The first cell 170 and the second cell 180. In addition, in the region where the second cell 180 and the third cell 190 overlap while the mobile communication terminal 100 moves from the second cell 180 to the third cell 190, the active set is the second cell. 180 and a third cell.

The mobile communication terminal 100 may be various digital electronic devices such as a mobile phone, a personal digital assistant (PDA), a laptop computer, and may be connected to a data network and / or another PSTN through a base station (Node B) 120. Various types of devices may be taken, including devices.

The base station (Node B) 120, 130, 140 sets up a call so that the mobile communication terminal (not shown) can perform voice communication and data communication under the control of the base station controller (RNC) 150.

The base station controller (RNC) 150 is connected to an overload control device 400 that controls the overload of the base station controller (RNC) 150. The base station controller (RNC) 150 controls the connected base stations (Node B) 120, 130, 140, and provides handover execution, operation time, and system management services.

The overload control device 400 receives load information of the base station (Node B) 120, 130, 140 and the base station controller (RNC) 150. The load information may be determined by, for example, an outgoing call, an incoming call, a location registration number, or a pilot channel Ec / Io transmitted from the base station (Node B) 120, 130, and 140. The overload control device 400 compares the received load information with a preset threshold to determine whether the overload. In addition, the overload control device 400 determines that the base station (Node B) 120, 130, 140 and the base station controller (RNC) 150 are overloaded to set the number of active sets of cells to perform handover. Transmits the control signal to set the value corresponding to the degree of overload. Here, the number of cells in the active set is changed in accordance with the degree of overload in order to efficiently manage radio resources of the mobile communication system. This will be described in more detail with reference to FIGS. 3 to 5.

Referring to Figure 3, the overload control method according to the present invention is performed by a soft handover algorithm as follows.

While the mobile communication terminal 110 is located in the first cell 170, the mobile communication terminal 110 is wirelessly linked with the first base station (Node B) 120, 130, 140, 120. have. However, when the mobile communication terminal 110 moves from the first cell 170 toward the second cell 180, the mobile communication terminal 110 is a first base station (Node B) (120, 130) 140 and pilot channels from the second base station (Node B) 120, 130, 140. If the pilot channel of the second cell (second cell pilot Ec / Io) is most strongly measured in the active set for the pilot channel which is the handover measurement amount during the period of the first trigger time DELTA T1, the pilot channel of the first cell If greater than the intensity (pilot Ec / Io of the first cell) minus (Thresholding_Range-Hysteresis_Event1A value for soft handover) and the number of preset active sets is not yet fully occupied, the second cell Is added to the active set. This case is called event 1A or radio link addition.

When the mobile communication terminal 110 moves from the second cell 180 toward the third cell 190, the mobile communication terminal 110 is connected to the third base station (node B) 120, 130, 140. Is receiving an increasingly strong pilot channel. If the pilot channel strength received from the first base station (Node B) 120, 130, 140 during the period of the third trigger time DELTA T3 is at the pilot channel strength of the second cell with the strongest measurement in the active set (soft hand If greater than minus the threshold for reporting (Reporting_Range-Hysteresis_Event1B), the first cell is removed from the active set. This case is called event 1B or radio link removal.

If the preset number of active sets is completely full and the pilot channel strength of the third cell, which is the strongest measured in the monitored set continuously measured at the mobile communication terminal during the period of the second trigger time ΔT2, is measured (weakest in the active set) If greater than the pilot channel strength + hysteresis_event1C) of the first cell, the weakest first cell in the active set is replaced with the strongest third cell among the cells continuously measured at the mobile communication terminal. This case is called event 1C or combined radio link addition and removal.

Since terms and parameters used in the above-described soft handover algorithm is apparent to the same bar, one of ordinary skill in the art and the 3GPP (3 ^rd Generation Partnership Project) standard, the description thereof will be omitted.

Figure 4 is a block diagram of an overload control device according to an embodiment of the present invention.

Referring to FIG. 4, the overload control apparatus 400 may include a load measuring unit 410 measuring load information at predetermined time intervals, and an overload determination unit 420 determining whether an overload has occurred by comparing the load information with a preset threshold value. ), A parameter change unit 430 for setting a parameter for controlling the active set according to the degree of overload, and an active set control unit for transmitting a control signal for adjusting the number of cells in the active set in response to the degree of overload ( 440). In this case, the overload control device 400 may be included as a part of the base station controller 150, and may be connected to the base station controller 150 as a separate device.

The load measuring unit 410 measures the base station (node B) 120, 130, 140 and the base station controller (node B) 120, 130, 140 and the base station controller (RNC) 150 measured at regular intervals. RNC) receives the load information measuring the load ratio of 150. In this case, the load rate may be determined by, for example, an outgoing call, an incoming call, a location registration number, or a pilot channel Ec / Io transmitted from the base station (Node B) 120, 130, and 140.

The overload judging unit 420 compares load information of the base station (Node B) 120, 130, 140 and the base station controller (RNC) 150 received by the load measuring unit 410 with a preset threshold. Node B) (120, 130, 140) and the base station controller (RNC) 150 to determine the degree of overload. The overload determination unit 420 may be classified into major, minor, and critical classes according to the degree of overload of the base station (Node B) 120, 130, and 140 and the base station controller (RNC) 150. Depending on the class, the parameter controlling the number of active set cells and the number of cells in the active set may be changed. This is to efficiently manage system resources according to the degree of overload.

The parameter changing unit 430 sets a parameter for controlling the active set according to the degree of overload. The parameter changing unit 430 may adjust the active set by changing hysteresis values for adding, deleting, and exchanging cells for a radio link in order to control a preset active set. In particular, the parameter changing unit 430 may change the hysteresis value for the event 1c according to the overload level. The parameters will be described in more detail in Table 1.

The active set controller 440 transmits a control signal for adjusting the number of cells of the active set according to the degree of overload. The active set controller 440 may adjust the number of active set cells by using a changed parameter according to the degree of overload. If the overload class is a minor class, the hysteresis value for the event 1c may be set to a preset Minor_1c_Hysteresis value to transmit a measurement control message to the mobile communication mobile communication terminal 110 to adjust the number of cells in the active set.

In addition, the active set control unit 440, for example, the maximum number of cells of the maximum active set in the normal state for each base station (Node B) (120, 130, 140)-if the Minor_MaxActiveSet is greater than "2", The number of active set cells is controlled to be set to the steady state maximum number of active set cells-Minor_MaxActiveSet. In addition, the active set controller 440 may control to set the maximum active set cell number to 2 if the number of cells of the maximum active set in the normal state-Minor_MaxActiveSet is less than or equal to "2". That is, when the degree of overload is a minor grade, the parameter Minor_MaxActiveSet corresponding to the minor grade is set to 1 by the parameter changing unit 430 in the normal state of the base station (Node B) 120, 130, and 140. If the number of cells in the maximum active set of is " 6 ", then if the load rate rating of the base station (Node B) 120, 130, 140 or the base station controller (RNC) 150 rises to the " minor " The number of active set cells of (120, 130, 140) becomes "5". That is, the active set controller 440 may control to change the number of cells of the active set for handover according to the minor grade, major grade, and threshold grade classified according to the degree of overload.

5 is a flowchart illustrating an overload control method according to an exemplary embodiment of the present invention.

In general, as the number of active sets of cells that can occupy the maximum number in a mobile communication system increases, the number of handovers may increase. Therefore, if the number of cells of the maximum occupied active set is controlled, the number of handover occurrences can be controlled. Of course, by reducing the maximum number of active set cells, handover (wireless link addition and removal) by event 1c may be increased. Here, event 1c refers to a case in which the inactive primary common pilot channel (CPICH) strength is better than the active primary common pilot channel strength. Therefore, in the present invention, if the hysteresis value for the event 1c is defined to be adjusted together, the overall number of handover occurrences can be reduced.

Table 1 below describes the parameters for explaining the soft handover method of the present invention.

Table 1

Parameter name meaning Remarks Critical_MaxActiveSet Maximum number of active set cells to decrease when the rating of the load rate of the base station (Node B) 120, 130, 140 or the base station controller (RNC) 150 is Critical. However, the maximum number of active set cells in the normal state-If Critical_MaxActiveSet <"2", the maximum number of active set cells of the base station (node B) (120, 130, 140) is set to "2" to operate. do. Example) If Critical_MaxActiveSet = 3 and the number of cells of the maximum active set in the normal state of the base station (Node B) 120, 130, 140 is "6", the base station (Node B) 120, 130, 140 or When the load rate class of the base station controller (RNC) 150 rises to the "Critical" class, the maximum number of active set cells of the corresponding base station (Node B) 120, 130, 140 becomes "3". Major_MaxActiveSet Maximum number of active set cells to decrease when the rating of the load rate of the base station (Node B) 120, 130, 140 or the base station controller (RNC) 150 is Major. However, the maximum number of active set cells in the normal state-If Major_MaxActiveSet <"2", the maximum number of active set cells of the base station (node B) (120, 130, 140) is set to "2" to operate. do. Example) If Major_MaxActiveSet = 2 and the number of cells of the maximum active set in the normal state of the base station (Node B) 120, 130, 140 is "6", the base station (Node B) 120, 130, 140 or When the load rate class of the base station controller (RNC) 150 rises to the "Major" class, the maximum number of active set cells of the corresponding base station (Node B) 120, 130, 140 becomes "4". Minor_MaxActiveSet The maximum number of active set cells to decrease when the class of load rate of the base station (Node B) 120, 130, 140 or the base station controller (RNC) 150 is the minor class. However, the maximum number of active set cells in the normal state-If Minor_MaxActiveSet <"2", the maximum number of active set cells of the base station (node B) (120, 130, 140) is set to "2" to operate. do. Example) If Minor_MaxActiveSet = 1 and the number of cells of the maximum active set in the normal state of the base station (Node B) 120, 130, 140 is "6", the base station (Node B) 120, 130, 140 or When the load rate class of the base station controller (RNC) 150 rises to the "Minor" class, the maximum number of active set cells of the corresponding base station (Node B) 120, 130, 140 becomes "5". Normal_MaxActiveSet Maximum number of active set cells when the load rate rating of the base station (Node B) 120, 130, 140 or the base station controller (RNC) 150 is less than Minor (no overload state) Critical_1c_Hysteresis Hysteresis value for event 1c when the load rating of base station (Node B) 120, 130, 140 or base station controller (RNC) 150 is Critical Major_1c_ Hysteresis Hysteresis value for event 1c when the load rating of base station (Node B) 120, 130, 140 or base station controller (RNC) 150 is Major Minor_1c_ Hysteresis Hysteresis value for event 1c when the load rating of base station (Node B) 120, 130, 140 or base station controller (RNC) 150 is Minor Normal_1c_ Hysteresis Hysteresis value for event 1c when the load rating of the base station (Node B) 120, 130, 140 or the base station controller (RNC) 150 is less than Minor (no overload condition)

Hereinafter, the overload control method according to an exemplary embodiment of the present invention will be described with reference to FIG. 5. In step S510, the base station (node B) 120, 130, 140 and the base station controller (RNC) 150 periodically. Measure your own load information. The load information may be determined by, for example, an outgoing call, an incoming call, a location registration number, or a pilot channel Ec / Io transmitted from the base station (Node B) 120, 130, and 140.

In step S520, it is determined whether an overload has occurred because a load exceeding a predetermined threshold is applied by the base station (node B) 120, 130, 140 or the base station controller (RNC) 150. If it is determined that the overload has occurred in the base station (Node B) 120, 130, 140 or the base station controller (RNC) 150, and performs the operation corresponding to the overload control algorithm corresponding to each overload class.

In step S532 to step S536, if the overload class is a minor class, the hysteresis value for the event 1c is set to the Minor_1c_Hysteresis value, and the measurement control message is transmitted to the terminal, and each base station (node B) 120, 130, 140) Max Active Set Cells in Normal State-set to max.-Minor_MaxActiveSet is greater than "2", Minor Max Active Set Cells in Minor State set to Maximum Active Set Cells-Minor_MaxActiveSet, if "2" If less than or equal, set the maximum number of active set cells = 2 in the minor grade. For example, if Minor_MaxActiveSet = 1 and the number of cells of the maximum active set in the normal state of the base station (Node B) 120, 130, 140 was "6", then the base station (Node B) 120, 130, 140 ) Or when the load rate class of the base station controller (RNC) 150 rises to the "Minor" class, the maximum number of active set cells of the corresponding base station (Node B) 120, 130, 140 becomes "5".

In steps S542 to S546, if the overload class is a major class, the hysteresis value for the event 1c is set to Major_1c_Hysteresis value, and the measurement control message is transmitted to the terminal, and each base station (node B) 120, 130 , The maximum number of active set cells in the normal state, which is set by 140)-if Major_MaxActiveSet is greater than "2", the maximum number of active set cells in the normal state is set to the maximum number of active set cells-Major_MaxActiveSet, if less than "2" Equal to or equal to, the maximum number of active set cells = 2 is set. For example, if Major_MaxActiveSet = 2 and the number of cells of the maximum active set in the normal state of the base station (Node B) 120, 130, 140 is "6", the base station (Node B) 120, 130, 140 ) Or when the load rate class of the base station controller (RNC) 150 rises to the "Major" class, the maximum number of active set cells of the corresponding base station (Node B) 120, 130, 140 becomes "4".

In step S552 to step S556, if the overload grade is a critical grade, the hysteresis value for the event 1c is set to the critical_1c_Hystetresis value to transmit a measurement control message to the terminal, and each base station (node B) 120, 130, 140) The maximum number of active set cells in the normal state set by-critical_MaxActiveSet is greater than "2", the maximum number of active set cells in the normal state is set to the maximum number of active set cells-critical_MaxActiveSet in the normal state, and less than "2" If it is equal, set the maximum number of active set cells = 2. For example, if Critical_MaxActiveSet = 3 and the number of cells in the maximum active set in the normal state of the base station (Node B) 120, 130, 140 was "6", then the base station (Node B) 120, 130, 140 or when the load rate class of the base station controller (RNC) 150 rises to the "Critical" class, the maximum number of active set cells of the base station (node B) 120, 130, 140 becomes "3".

According to the overload control method according to the present invention, the mobile communication system adjusts the maximum number of active sets of cells utilized for handover according to the overload class of the base station (Node B) and the base station controller (RNC) 150. The number of handovers can be reduced, thereby reducing the load on the mobile communication system.

In addition, the overload control method according to the present invention includes all DCH (except Adaptive Multi-Rate speech codec), CS (Circuited Switched) video calls, and PS (Packet Switched) HSDPA (High Speed Down-link Packet Access) calls. It may also be applied to a dedicated channel (SR) call or a signaling radio bearer (SRB). In addition, according to the present invention, the overload control method can be defined and operated individually for each traffic type. That is, QoS (Quality of Service) for each traffic type is determined by separately setting Minor_MaxActiveSet, Major_MaxActiveSet, Critical_MaxActiveSet, Minor_1c_Hysteresis, Major_1c_ Hysteresis, Critical_1c_ Hysteresis values for each AMR call, CS video call, PS Data call per bearer and Signaling Radio Bearer (SRB). Can be guaranteed differentially.

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

In the overload control method according to the present invention, if the overload control is performed through the control of the number of handover occurrences, not only the effective call rate reduction effect can be achieved with the minimum call processing signaling control, but also the quality degradation of subscribers is minimized. Since the load ratio of the system can be controlled, the overload of the mobile communication system can be effectively controlled.

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art to which the present invention pertains without departing from the spirit and scope of the present invention as set forth in the claims below It will be appreciated that modifications and variations can be made.

Claims (11)

In the overload control device in a mobile communication system, A load measuring unit measuring load information every preset time; An overload determining unit configured to determine whether an overload has occurred by comparing the load information with a preset threshold value; A parameter change unit configured to set a parameter value for adjusting the active set according to the degree of overload when the overload occurs as a result of the determination; And And an active set setting unit for generating a control signal for controlling an active set for handover using a parameter corresponding to the degree of overload. The method of claim 1, The load information is load information for each base station or base station controller, and is determined as one or more selected from the group consisting of the number of outgoing calls, the number of incoming calls, the number of location registrations, or the pilot channel strength (Ec / Io) transmitted by the base station. Overload control device, characterized in that. The method of claim 1, The parameter for adjusting the active set is that when the cells of the active set are replaced, the pilot channel strength of the cell that is most strongly measured in the monitored set, in which the number of preset active sets is completely filled and continuously measured at the mobile communication terminal for a certain period, is active And an adjustment parameter for adjusting the number of cells included in the active set or the hysteresis parameter for the event 1c generated when the pilot channel strength of the weakest measured cell in the set is greater. The method of claim 3, And the active set setting unit adjusts cell replacement of the active set using hysteresis parameters for event 1c corresponding to the degree of overload. The method of claim 3, The active set setting unit sets the adjustment parameter corresponding to the degree of overload and sets the number of cells in the active set to 2 when the value of the maximum active set cell minus the value corresponding to the adjustment parameter is less than 2 in the normal state. And generating a control signal for setting the subtracted value to the number of cells in the active set when the subtracted value is greater than 2. The method of claim 1, The overload control device includes all dedicated channel (DCH) calls except for adaptive multi-rate speech codec (AMR), circuit switched (CS) video calls, packet switched (PS) high speed down-link packet access (HSDPA) calls, and Overload control device, characterized in that applied to control any one selected from the group consisting of Signaling Radio Bearer (SRB). The method of claim 1, The overload control device is included as part of the base station controller, or overload control device, characterized in that interlocked with the base station controller as a separate device. In the method for controlling overload in a mobile communication system, Measuring load information at a preset time; Determining whether an overload has occurred by comparing the load information with a preset threshold value; If an overload occurs as a result of the determination, setting a parameter for adjusting the active set according to the degree of overload; And Generating a control signal for controlling an active set for handover according to the degree of overload using the parameter, The parameter indicates that when the cell of the active set is replaced, the pilot channel strength of the cell that is measured most strongly in the monitored set, where the number of preset active sets is completely full and is continuously measured at the mobile terminal for a period of time, is measured the weakest in the active set. An overload control method comprising a hysteresis parameter for an event 1c generated when the pilot channel strength of the cell is greater than the cell or an adjustment parameter for adjusting the number of cells included in the active set The method of claim 8, Generating the control signal Generating a control signal for controlling cell replacement of an active set using the hysteresis parameter for event 1c corresponding to the degree of overload. The method of claim 8, Generating the control signal Subtracting a value corresponding to the adjustment parameter corresponding to the degree of overload from the number of cell cells of the maximum active set in the steady state; Generating a control signal that sets the number of cells in the active set to 2 when the subtracted value is less than 2, and sets the subtracted value to the number of cells in the active set when the subtracted value is greater than 2. Overload control method, characterized in that. What is claimed is: 1. A recording medium readable by an electronic device having recorded thereon a program comprising typed instructions for executing a method for controlling overload in a mobile communication system. Measuring load information at a preset time; Determining whether an overload has occurred by comparing the load information with a preset threshold value; If an overload occurs as a result of the determination, changing a parameter for adjusting the active set according to the degree of overload; And Generating a control signal for controlling an active set for handover according to the degree of overload using the parameter, The parameter indicates that when the cell of the active set is replaced, the pilot channel strength of the cell that is measured most strongly in the monitored set, where the number of preset active sets is completely full and is continuously measured at the mobile terminal for a period of time, is measured the weakest in the active set. A program recording the program executing the overload control method, comprising a hysteresis parameter for the event 1c generated when the pilot channel strength of the cell is greater or an adjustment parameter for adjusting the number of cells included in the active set media.

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