KR20100085360A - Method for dispersing load in communication system and communication system using the same - Google Patents

Abstract

PURPOSE: A load dispersing method of a communication system and the communication system using the same are provided to perform handover in order to change data transmission path of a mobile terminal considering the load of each network. CONSTITUTION: The first mobile connection device(211) is appointed to the first network which at least one mobile terminal is connected. In case the load of the first network exceeds the set limitation load, the first mobile connection device determines a mobile terminal for handover among at least one mobile terminal is connected and the secondary network which the mobile terminal for handover performs the handover. The mobile terminal for handover performs the handover to the secondary network according to the determination of the first mobile connection device.

Description

Load balancing method of communication system and communication system using same {METHOD FOR DISPERSING LOAD IN COMMUNICATION SYSTEM AND COMMUNICATION SYSTEM USING THE SAME}

The present invention relates to a load balancing method and a communication system using the same in a communication system supporting a proxy mobile internet protocol (PMIP).

Recently, with the spread of mobile terminals and the realization of high speed networks, the demand for Internet services is increasing. That is, the number of users is increasing due to the improvement of the performance of mobile terminals such as portable computers and PDAs and the development of wireless communication technologies.

When the mobile terminal moves from the current network to another network, the network identifiers change and therefore the mobile terminal's IP address. This means that packets in the IP layer are routed according to the network identifier of the destination address, so that the mobile terminal cannot communicate when moved to another network.

Therefore, mobility must be ensured in order to continue communication while maintaining the existing IP address. Mobile IP (hereinafter referred to as 'MIP') has been proposed to ensure mobility in the Internet environment.

However, the recent trend of increasing the number of wireless Internet users is that MIPv4's addressing system is 32-bit, so that it cannot meet the ever-increasing IP address requirements. There is an active research to provide mobility.

MIPv6 has an advantage of transparency because an application only needs to be installed in three related nodes, namely, a Correspondent Node (CN), a Home Agent (HA), and a Mobile Node (MN). In addition, MIPv6 can use link disconnection detection and registration to a new subnet in the same manner as the existing IP.

However, in MIPv6, there is a problem that packets may be lost while moving due to an increase in demand for real-time traffic. This is represented by the so-called disconnection phenomenon.

Therefore, there is a growing need to perform a handover while preventing data from being interrupted in transmission and reception to suit a current network environment.

The present invention provides a load balancing that can perform a handover for changing a data transmission path of a mobile terminal in consideration of the load of each network in a communication system supporting a proxy mobile internet protocol (PMIP). It is an object of the present invention to provide a method and a communication system using the same.

A load balancing method of a communication system supporting a proxy mobile internet protocol (hereinafter referred to as "PMIP") related to an example of the present invention for realizing the above-described problem, may include a first mobile access means designated to a first network. In a state where at least one mobile terminal is connected to the first network via the first mobile access unit, the first mobile access unit may include: measuring a load of the first network; Comparing the measured load with a preset limit load; As a result of the comparison, when the measured load exceeds the limit load, a handover target mobile terminal and a second network to be handed over by the handover target mobile terminal are determined among at least one mobile terminal connected to the first network. Making; And handing over to the second network by the handover target mobile terminal according to the determination result.

In addition, a load balancing method of a communication system supporting PMIP according to an embodiment of the present invention for realizing the above object, the mobile control station, the step of receiving the load information of the network, respectively from at least one mobile connection means; Calculating an average load index for the entire network by using the received load information; If the calculated average load index is less than a predetermined limit load index, determining a first network having the largest network load as an overload network by using the received load information; Transmitting a load balancing request message to first mobile access means designated to a first network determined as said overload network; The first mobile access means, upon receiving the load balancing request message, of the at least one mobile terminal connected to the first network, a handover target mobile terminal and a second network to which the handover target mobile terminal will handover. Determining; And handing over to the second network by the handover target mobile terminal according to the determination result.

In addition, the communication system supporting the PMIP according to an embodiment of the present invention for realizing the above-mentioned problem is assigned to a first network to which at least one mobile terminal is connected, and the load of the first network is a preset limit load. First mobile access means for determining a handover target mobile terminal and a second network to which the handover target mobile terminal is to be handed over from among the connected at least one mobile terminal; And a handover target mobile terminal for handing over to the second network according to the determination of the first mobile access means.

In addition, the communication system supporting the PMIP according to an embodiment of the present invention for realizing the above problem, the average load index for the entire network calculated by using the load information of the corresponding network respectively received from at least one mobile access means; A mobile control station for determining a first network having the largest network load as an overload network using the received load information when a value is less than a preset limit load index; A handover target mobile terminal and the handover target mobile terminal among the at least one connected mobile terminal are assigned to the first network to which at least one mobile terminal is connected and receive a load balancing request message from the mobile control station. First mobile access means for determining a second network to which to hand over; And a handover target mobile terminal handing over to the second network according to the determination of the first mobile access means.

Load balancing method of a communication system related to at least one embodiment of the present invention configured as described above and the effects by the communication system using the same are as follows.

First, it is possible to properly distribute the load of each network in a communication system supporting the proxy mobile internet protocol, in particular, a heterogeneous network integrated communication system.

Second, the handover can be performed smoothly without any major disruption to the QoS of the selected mobile handover target terminal to adjust the load of the network.

Third, since the load placed on each network can be balanced, data transmission delay due to insufficient network data transmission capacity can be minimized.

Hereinafter, a mobile terminal according to the present invention will be described in more detail with reference to the accompanying drawings. The suffixes "module" and "unit" for components used in the following description are given or used in consideration of ease of specification, and do not have distinct meanings or roles from each other.

The mobile terminal described herein may include a mobile phone, a smart phone, a laptop computer, a digital broadcasting terminal, a personal digital assistant (PDA), a portable multimedia player (PMP), a navigation device, and the like.

However, it will be readily apparent to those skilled in the art that the configuration according to the embodiments described herein may also be applied to fixed terminals such as digital TVs, desktop computers, etc., except when applicable only to mobile terminals.

Hereinafter, with reference to FIG. 1, the configuration of a mobile terminal according to the present invention will be described in detail.

1 is a block diagram of a mobile terminal according to an embodiment of the present invention.

The mobile terminal 100 includes a wireless communication unit 110, an A / V input unit 120, a user input unit 130, a sensing unit 140, an output unit 150, a memory 160, and an interface. The unit 170, the controller 180, and the power supply unit 190 may be included. The components shown in FIG. 1 are not essential, so that a mobile terminal having more or fewer components may be implemented.

Hereinafter, the components will be described in order.

The wireless communication unit 110 may include one or more modules that enable wireless communication between the mobile terminal 100 and the wireless communication system or between the mobile terminal 100 and a network in which the mobile terminal 100 is located. For example, the wireless communication unit 110 may include a broadcast receiving module 111, a mobile communication module 112, a wireless Internet module 113, a short range communication module 114, and a location information module 115 .

The broadcast receiving module 111 receives a broadcast signal and / or broadcast related information from an external broadcast management server through a broadcast channel.

The broadcast channel may include a satellite channel and a terrestrial channel. The broadcast management server may mean a server that generates and transmits a broadcast signal and / or broadcast related information or a server that receives a previously generated broadcast signal and / or broadcast related information and transmits the same to a terminal. The broadcast signal may include not only a TV broadcast signal, a radio broadcast signal, and a data broadcast signal, but also a broadcast signal having a data broadcast signal combined with a TV broadcast signal or a radio broadcast signal.

The broadcast related information may mean information related to a broadcast channel, a broadcast program, or a broadcast service provider. The broadcast related information may also be provided through a mobile communication network. In this case, it may be received by the mobile communication module 112.

The broadcast related information may exist in various forms. For example, it may exist in the form of Electronic Program Guide (EPG) of Digital Multimedia Broadcasting (DMB) or Electronic Service Guide (ESG) of Digital Video Broadcast-Handheld (DVB-H).

The broadcast receiving module 111 may include, for example, Digital Multimedia Broadcasting-Terrestrial (DMB-T), Digital Multimedia Broadcasting-Satellite (DMB-S), Media Forward Link Only (MediaFLO), and Digital Video Broadcast (DVB-H). Digital broadcast signals can be received using digital broadcasting systems such as Handheld and Integrated Services Digital Broadcast-Terrestrial (ISDB-T). Of course, the broadcast receiving module 111 may be configured to be suitable for not only the above-described digital broadcasting system but also other broadcasting systems.

The broadcast signal and / or broadcast related information received through the broadcast receiving module 111 may be stored in the memory 160.

The mobile communication module 112 transmits and receives a wireless signal with at least one of a base station, an external terminal, and a server on a mobile communication network. The wireless signal may include various types of data according to transmission and reception of a voice call signal, a video call call signal, or a text / multimedia message.

The wireless internet module 113 refers to a module for wireless internet access and may be embedded or external to the mobile terminal 100. Wireless Internet technologies may include Wireless LAN (Wi-Fi), Wireless Broadband (Wibro), World Interoperability for Microwave Access (Wimax), High Speed Downlink Packet Access (HSDPA), and the like.

The short range communication module 114 refers to a module for short range communication. As a short range communication technology, Bluetooth, Radio Frequency Identification (RFID), Infrared Data Association (IrDA), Ultra Wideband (UWB), ZigBee, and the like may be used.

The location information module 115 is a module for obtaining a location of a mobile terminal, and a representative example thereof is a GPS (Global Position System) module.

Referring to FIG. 1, the A / V input unit 120 is for inputting an audio signal or a video signal, and may include a camera 121 and a microphone 122. The camera 121 processes image frames such as still images or moving images obtained by the image sensor in the video call mode or the photographing mode. The processed image frame may be displayed on the display unit 151.

The image frame processed by the camera 121 may be stored in the memory 160 or transmitted to the outside through the wireless communication unit 110. Two or more cameras 121 may be provided according to the use environment.

The microphone 122 receives an external sound signal by a microphone in a call mode, a recording mode, a voice recognition mode, etc., and processes the external sound signal into electrical voice data. The processed voice data may be converted into a form transmittable to the mobile communication base station through the mobile communication module 112 and output in the call mode. The microphone 122 may implement various noise removing algorithms for removing noise generated in the process of receiving an external sound signal.

The user input unit 130 generates input data for the user to control the operation of the terminal. The user input unit 130 may include a key pad dome switch, a touch pad (static pressure / capacitance), a jog wheel, a jog switch, and the like.

The sensing unit 140 detects a current state of the mobile terminal 100 such as an open / closed state of the mobile terminal 100, a location of the mobile terminal 100, presence or absence of a user contact, orientation of the mobile terminal, acceleration / deceleration of the mobile terminal, and the like. To generate a sensing signal for controlling the operation of the mobile terminal 100. For example, when the mobile terminal 100 is in the form of a slide phone, it may sense whether the slide phone is opened or closed. In addition, whether the power supply unit 190 is supplied with power, whether the interface unit 170 is coupled to the external device may be sensed. The sensing unit 140 may include a proximity sensor 141.

The output unit 150 is used to generate an output related to sight, hearing, or tactile sense, and includes a display unit 151, an audio output module 152, an alarm unit 153, and a haptic module 154. Can be.

The display unit 151 displays (outputs) information processed by the mobile terminal 100. For example, when the mobile terminal is in a call mode, the mobile terminal displays a user interface (UI) or a graphic user interface (GUI) related to the call. When the mobile terminal 100 is in a video call mode or a photographing mode, the mobile terminal 100 displays photographed and / or received images, a UI, and a GUI.

The display unit 151 includes a liquid crystal display (LCD), a thin film transistor-liquid crystal display (TFT LCD), an organic light-emitting diode (OLED), and a flexible display (flexible). and at least one of a 3D display.

Some of these displays can be configured to be transparent or light transmissive so that they can be seen from the outside. This may be referred to as a transparent display. A representative example of the transparent display is TOLED (Transparant OLED). The rear structure of the display unit 151 may also be configured as a light transmissive structure. With this structure, the user can see the object located behind the terminal body through the area occupied by the display unit 151 of the terminal body.

There may be two or more display units 151 according to the implementation form of the mobile terminal 100. For example, in the mobile terminal 100, a plurality of display portions may be spaced apart from one another, or may be disposed integrally with one another, and may be disposed on different surfaces, respectively.

When the display unit 151 and a sensor for detecting a touch operation (hereinafter, referred to as a touch sensor) form a mutual layer structure (hereinafter referred to as a touch screen), the display unit 151 may be configured in addition to an output device. Can also be used as an input device. The touch sensor may have, for example, a form of a touch film, a touch sheet, a touch pad, or the like.

The touch sensor may be configured to convert a change in pressure applied to a specific portion of the display unit 151 or capacitance generated in a specific portion of the display unit 151 into an electrical input signal. The touch sensor may be configured to detect not only the position and area of the touch but also the pressure at the touch.

If there is a touch input to the touch sensor, the corresponding signal (s) is sent to the touch controller. The touch controller processes the signal (s) and then transmits the corresponding data to the controller 180. As a result, the controller 180 can know which area of the display unit 151 is touched.

Referring to FIG. 1, a proximity sensor 141 may be disposed in an inner region of the mobile terminal or in the vicinity of the touch screen, which is surrounded by the touch screen. The proximity sensor 141 refers to a sensor that detects the presence or absence of an object approaching a predetermined detection surface or an object present in the vicinity without using a mechanical contact by using an electromagnetic force or infrared rays. Proximity sensors have a longer life and higher utilization than touch sensors.

Examples of the proximity sensor 141 include a transmission photoelectric sensor, a direct reflection photoelectric sensor, a mirror reflection photoelectric sensor, a high frequency oscillation proximity sensor, a capacitive proximity sensor, a magnetic proximity sensor, and an infrared proximity sensor. When the touch screen is capacitive, the touch screen is configured to detect the proximity of the pointer by the change of the electric field according to the proximity of the pointer. In this case, the touch screen (touch sensor) may be classified as a proximity sensor.

Hereinafter, for convenience of explanation, the act of allowing the pointer to be recognized without being in contact with the touch screen so that the pointer is located on the touch screen is referred to as a "proximity touch", and the touch The act of actually touching the pointer on the screen is called "contact touch." The position where the proximity touch is performed by the pointer on the touch screen refers to a position where the pointer is perpendicular to the touch screen when the pointer is in proximity proximity.

The proximity sensor 141 detects a proximity touch and a proximity touch pattern (for example, a proximity touch distance, a proximity touch direction, a proximity touch speed, a proximity touch time, a proximity touch position, and a proximity touch movement state). Information corresponding to the sensed proximity touch operation and proximity touch pattern may be output on the touch screen.

The sound output module 152 may output audio data received from the wireless communication unit 110 or stored in the memory 160 in a call signal reception, a call mode or a recording mode, a voice recognition mode, a broadcast reception mode, and the like. The sound output module 152 may also output a sound signal related to a function (eg, a call signal reception sound, a message reception sound, etc.) performed in the mobile terminal 100. The sound output module 152 may include a receiver, a speaker, a buzzer, and the like.

The alarm unit 153 outputs a signal for notifying occurrence of an event of the mobile terminal 100. Examples of events occurring in the mobile terminal include call signal reception, message reception, key signal input, and touch input. The alarm unit 153 may output a signal for notifying occurrence of an event in a form other than a video signal or an audio signal, for example, vibration. The video signal or the audio signal may be output through the display unit 151 or the audio output module 152, so that they 151 and 152 may be classified as part of the alarm unit 153.

The haptic module 154 generates various tactile effects that the user can feel. Vibration is a representative example of the haptic effect generated by the haptic module 154. The intensity and pattern of the vibration generated by the haptic module 154 are controllable. For example, different vibrations may be synthesized and output or may be sequentially output.

In addition to vibration, the haptic module 154 may be configured to provide a pin array that vertically moves with respect to the contact skin surface, a jetting force or suction force of air through the jetting or suction port, grazing to the skin surface, contact of the electrode, electrostatic force, and the like. Various tactile effects can be generated, such as effects by the endothermic and the reproduction of a sense of cold using the elements capable of endotherm or heat generation.

The haptic module 154 may not only deliver the haptic effect through direct contact, but also may implement the user to feel the haptic effect through a muscle sense such as a finger or an arm. Two or more haptic modules 154 may be provided according to configuration aspects of the mobile terminal 100.

The memory 160 may store a program for the operation of the controller 180 and may temporarily store input / output data (for example, a phone book, a message, a still image, a video, etc.). The memory 160 may store data regarding vibration and sound of various patterns output when a touch input on the touch screen is performed.

The memory 160 may be a flash memory type, a hard disk type, a multimedia card micro type, a card type memory (for example, SD or XD memory), RAM (Random Access Memory, RAM), Static Random Access Memory (SRAM), Read-Only Memory (ROM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Programmable Read-Only Memory (PROM), Magnetic Memory, Magnetic It may include a storage medium of at least one type of disk, optical disk. The mobile terminal 100 may operate in connection with a web storage that performs a storage function of the memory 160 on the Internet.

The interface unit 170 serves as a path with all external devices connected to the mobile terminal 100. The interface unit 170 receives data from an external device, receives power, transfers the power to each component inside the mobile terminal 100, or transmits data inside the mobile terminal 100 to an external device. For example, a wired / wireless headset port, an external charger port, a wired / wireless data port, a memory card port, a port for connecting a device having an identification module, an audio I / O port, A video input / output (I / O) port, an earphone port, and the like may be included in the interface unit 170.

The identification module is a chip that stores various types of information for authenticating the use authority of the mobile terminal 100, and includes a user identification module (UIM), a subscriber identification module (SIM), and a universal user authentication module (UI). Universal Subscriber Identity Module (USIM), and the like. Devices with identification modules (hereinafter referred to as "identification devices") can be manufactured in a smart card format. Therefore, the identification device may be connected to the terminal 100 through a port.

The interface unit 170 may be a passage through which power from the cradle is supplied to the mobile terminal 100 when the mobile terminal 100 is connected to an external cradle, or various commands input by the user from the cradle. It may be a passage through which a signal is transmitted to the mobile terminal 100. Various command signals or power input from the cradle may operate as signals for recognizing that the mobile terminal 100 is correctly mounted on the cradle.

The controller 180 typically controls the overall operation of the mobile terminal 100. For example, perform related control and processing for voice calls, data communications, video calls, and the like. The controller 180 may include a multimedia module 181 for playing multimedia. The multimedia module 181 may be implemented in the controller 180 or may be implemented separately from the controller 180.

The controller 180 may perform a pattern recognition process for recognizing a writing input or a drawing input performed on the touch screen as text and an image, respectively.

The power supply unit 190 receives an external power source and an internal power source under the control of the controller 180 to supply power for operation of each component.

Various embodiments described herein may be implemented in a recording medium readable by a computer or similar device using, for example, software, hardware or a combination thereof.

According to a hardware implementation, embodiments described herein include application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), and the like. It may be implemented using at least one of processors, controllers, micro-controllers, microprocessors, and electrical units for performing other functions. The described embodiments may be implemented by the controller 180 itself.

According to the software implementation, embodiments such as the procedures and functions described herein may be implemented as separate software modules. Each of the software modules may perform one or more functions and operations described herein. Software code may be implemented in software applications written in a suitable programming language. The software code may be stored in the memory 160 and executed by the controller 180.

Prior to the detailed description of the present invention, a communication system to which the present invention is applicable will be described with reference to FIG.

2 is a structural diagram of a communication system according to an embodiment of the present invention. In particular, FIG. 2 illustrates a communication system in a heterogeneous network integration environment that supports the Proxy Mobile Internet Protocol (“PMIP”).

As shown in FIG. 2, each of the mobile access means 211, 221, 231 is assigned to the plurality of networks 210, 220, 230 in one PMIP domain. Thus, each of the mobile connection means 211, 221, 231 can support different networks.

For example, the network may include a wireless local area network (WLAN), worldwide interoperability for microwave access (WiMAX), universal mobile telecommunications system (UMTS), and the like. have.

The mobile access means 211, 221, 231 may be, for example, a mobile access gateway (MAG).

In order for the present invention to be applicable, at least one mobile terminal (100, 100-1, 100-2) is located in a common area that can service all the plurality of networks (210, 220, 230), at least one It is possible to connect with the mobile connection means 211, 221, 231.

Accordingly, in the environment shown in FIG. 2, any one of the mobile terminals 100, 100-1, and 100-2 has a load concentrated among the plurality of networks 210, 220, and 230 available at the current location. Handover to another network may be performed according to the load balancing determination of the mobile access means designated for the network.

There are two load balancing determination methods according to the present invention.

First, each mobile access means 211, 221, 231 periodically measures the load of the network 210, 220, 230, and may determine load distribution when the measured load exceeds a predetermined limit load. . Hereinafter, this is referred to as a first load balancing determination method.

Secondly, each mobile access means 211, 221, 231 periodically transmits load information of the network 210, 220, 230 to the mobile control station 240, and the mobile control station 240 receives the reception. When the average load index calculated using the calculated load information is less than the limit load index, the load split request message may be transmitted to the network that delivered the largest load information. Thus, the mobile access means having received the load balancing request message can determine the load balancing. Hereinafter, this is referred to as a second load balancing determination method.

The above-described load balancing determination method will be described in more detail below.

As shown in Fig. 2, the communication system according to the present invention includes a mobile control station 240 and a mobile control station (especially load management) for managing all networks 210, 220, and 230 belonging to one PMIP domain. It may include a registration management server 250 that manages the connection and registration of the terminal network.

Here, the mobile control station 240 is, for example, a link mobility anchor (LMA), and the registration management server 250 is, for example, an authentication, authorization, and accounting server (Authentication, Authorization, Accounting Server). May be).

3 and 4, a detailed description will be given of a load balancing method of a communication system and a handover method according to load balancing determination.

3 is a flowchart of a load balancing method of a communication system according to an embodiment of the present invention, and FIG. 4 is a flowchart of a handover method according to load balancing determination in a communication system according to an embodiment of the present invention.

For convenience of description, it may be assumed that the communication system mentioned below has the structure shown in FIG. 2.

In addition, the mobile terminals 100, 100-1, and 100-2 mentioned below may include interfaces suitable for each network so that a plurality of networks can be serviced, and each of the plurality of networks may be adapted for each network. It may be provided with corresponding interfaces or integrated interfaces suitable for all serviceable networks. For example, the mobile terminal 100 may access the first network 210 through an interface suitable for the first network 210 when the first network 210 is connected.

First, the first load balancing determination method will be described in detail with reference to FIG. 3. For convenience of explanation, the description will be limited to the load balancing determination by the first mobile connection means 211. Of course, the load balancing determination method can also be performed in the second and third mobile connection means (221, 231).

As shown in FIG. 3, the first mobile connection means 211 measures the load of the first network 210 to which it is assigned (S311).

In the measuring step S311, the first mobile connection means 211 may periodically measure the load of the first network 210.

In the measuring step S311, the first mobile access unit 211 may measure the packet arrival rate at predetermined time intervals according to a predetermined period, and measure the average packet arrival rate at every predetermined number of times.

The average packet arrival rate (which is the average packet arrival rate of the i-th mobile access means for every N _m measurement) can be calculated as follows.

Here, the jth measured packet arrival rate is λ _j (1 ≦ _j ≦ N _m ).

The load of the i-th mobile connecting means can be calculated as follows.

⁼

⁼

는, i번째 이동 접속 수단의 평균 서비스율이라고 할 수 있다.From here,

Is an average service rate of the i-th mobile connection means.

The first mobile access unit 211 may compare the load measured in the measuring step S313 with the preset limit load (S315).

Here, the limit load may mean a maximum acceptable load considering the packet throughput of the first mobile access means 211.

When it is determined that the load measured in the performing result measuring step S313 of the comparing step S315 exceeds the limit load, the first mobile access unit 211 may determine load balancing.

Next, with reference to FIG. 3, the 2nd load balancing determination method is demonstrated in detail.

As shown in FIG. 3, the mobile control station 240 may determine the network from the mobile access means 211, 221, 231 assigned to each of the plurality of networks 210, 220, 230 belonging to one PMIP domain. The load information is received (S321).

For example, the load information may include the load ρ _i calculated by the first and second equations described above.

Each of the mobile access means 211, 221, 231 can periodically or arbitrarily transmit a message (hereinafter, the "load information message") including load information to the mobile control station 240.

For example, the load information message may have a structure shown in FIG. 5 and may include load information in the 'Load Information field' 510.

In particular, in the PMIPv6 environment, a heartbeat message, which is a message periodically checking whether a connection between the mobile access means 211, 221, 231 and the mobile control station 240 is maintained, is marked with a 'flag N' and a 'Load Information'. It can be modified to have a field '510' and used as a load information message.

The mobile control station 240 may store the load information received in the reception step S321 in a database and use it in determining load balancing.

The mobile control station 240 calculates a load average index for all the networks 210, 220, and 230 belonging to one PMIP domain using the load information received in the reception step S321 (S323).

The mobile control station 240 may compare the load average index calculated in the calculation step S323 with the preset limit average index (S325).

The mobile control station 240 calculates the total load for the entire network 210, 220, 230 using the load information received in the reception step S321, and the calculated total load exceeds the preset limit load. In this case, the comparison step S325 may be performed.

Here, the limit load may mean a maximum load that can be processed in consideration of the packet throughput of the entire network 210, 220, 230.

The total load can be calculated as follows.

The load average index can be calculated as follows.

Here, ρ _i is the i-th network load received from the i-th mobile access means, and M may refer to the number of mobile access means connected to the mobile control station 240 in one PMIP domain.

When it is determined that the average load index is less than the threshold load index as a result of performing the comparing step S325, the mobile control station 240 overloads the network having the largest network load by using the load information received in the receiving step S321. It may be determined by the network (S327).

In the database of the mobile control station 240, load information for each network is stored, and the load information ρ _i for each network is included in the load information. May be included.

The mobile control station 240 transmits a load balancing request message to the overload network determined in the determination step S327 (S329).

Here, the load balancing request message may have the structure shown in FIG. 5, and in the PMIPv6 environment, the heartbeat message may be modified ('flag L' added) and used as the load balancing request message.

For example, when the load balancing request message has the structure shown in FIG. 5, when the load balancing request is made, the mobile control station 240 sets the value of 'flag L' to '1' and the 'Load Information field' 510. ) May be set to '0' and the 'Heartbeat Interval field' 520 may be set to '0'.

Hereinafter, for convenience of explanation, it is assumed that the first network 210 is determined as the overload network in the determination step S327.

Hereinafter, when load balancing is determined by the first and second load balancing determination methods, the mobile terminal handover process will be described.

The first mobile connection means 211 determines a handover target mobile terminal among at least one mobile terminal 100, 100-1, 100-2 connected to the first network 210, and determines the handover target mobile terminal. Determines a handover target network among all available networks 220 and 230 (except the first network 210) (S330).

The determination step S330 will be described in more detail with reference to FIG. 4.

The first mobile access means 211 receives a status report message from the mobile terminals 100, 100-1, and 100-2 connected to the first network 210 (S401).

Here, the status report message may mean a message for reporting the current status of the mobile terminal such as mobile terminal identification information, mobile terminal interface identification information, new access point (AP) / base station identification information, and mobile terminal signal strength information. Can be.

The receiving step S401 may be performed periodically.

When the load of the first network 210 exceeds the limit load (first load balancing determination method) or when the first mobile connection means 211 receives a load balancing request message from the mobile control station 240 ( In the second load balancing determination method), it is determined to perform load balancing (S403).

When the first mobile access means 211 determines to perform load balancing, the mobile terminal having the largest data request rate among the mobile terminals 100, 100-1, and 100-2 connected to the first network 210. May be determined as the handover target mobile terminal (S413).

For example, if the mobile terminal having the largest data demand rate establishes a real-time service session such as VoIP or IPTV with the first network 210, it may be excluded from the selection of the mobile terminal to be handed over.

In addition, if all of the mobile terminals 100, 100-1, and 100-2 connected to the first network 210 have established a real-time service session with the first network 210, the mobile station having the largest data request rate among them. The terminal may be determined to be a handover target mobile terminal.

In addition, when the first mobile access means 211 determines to perform load balancing, the handover target network among the networks 220 and 230 (except the first network 210) to which the handover target mobile terminal is accessible. It may be determined (S413).

The first mobile access means 211 initializes handover to the second and third mobile access means 221 and 231 designated in the second and third networks 220 and 230, respectively, in determining the handover target network. Send a message (S405, S409) and receive a handover grant message from the second and third mobile access means (221, 231) (S407, S411).

In this case, the handover grant message may include load information of the corresponding network. As shown in FIG. 5, in order to include load information, the handover hub message may include a 'flag N' and a 'Load Information field' 510.

Accordingly, the first mobile access unit 211 may determine the handover target network in consideration of load information of each network 220 and 230 and signal strength of the handover target mobile terminal.

Hereinafter, for convenience of description, it may be assumed that the first mobile terminal 100 is determined as the handover target mobile terminal and the second network 220 is determined as the handover target network.

The first mobile access means 211 transmits a handover command message to the first mobile terminal 100 determined as the handover target mobile terminal (S340, S415).

When the first mobile terminal 100 receives the handover command message, the first mobile terminal 100 performs a handover to the second network 220 determined as the handover target network (S350 and S417).

As the first mobile terminal 100 hands over to the second network 220, the second mobile access means 221 sends a Proxy Binding Update (PBU) message to the mobile control station 240. By transmitting the message, the first mobile terminal 100 may notify that the handover is performed to the second network 220 (S419).

Then, as the mobile control station 240 receives the PBU message from the second mobile access means 221, the binding cache entry (Binding) to the first mobile terminal 100 and the second network 220 which is a new access network. Cache Entry ('BCE') may be updated (S421).

The first mobile access means 211 may receive a Proxy Binding Acknowledgment message including the Home Network Prefix of the mobile terminal 100 from the mobile control station 240 (S423). .

The load balancing method of the communication system and the communication system using the same as described above are not limited to the configuration and method of the above-described embodiments, the above embodiments are all of the embodiments so that various modifications can be made Or some may be selectively combined.

1 is a block diagram of a mobile terminal according to an embodiment of the present invention.

2 is a structural diagram of a communication system according to an embodiment of the present invention;

3 is a flowchart of a load balancing method of a communication system according to an embodiment of the present invention.

4 is a flowchart of a handover method according to load balancing determination in a communication system according to an embodiment of the present invention.

5 is a structural diagram of a message according to an embodiment of the present invention.

Claims (18)

In the load balancing method of a communication system supporting a proxy mobile internet protocol, In a state in which at least one mobile terminal is connected to the first network through a first mobile access means designated to a first network, the first mobile access means comprising: measuring a load of the first network; Comparing the measured load with a preset limit load; As a result of the comparison, when the measured load exceeds the limit load, a handover target mobile terminal and a second network to be handed over by the handover target mobile terminal are determined among at least one mobile terminal connected to the first network. Making; And And the handover target mobile terminal performs handover to the second network according to the determination result. The method of claim 1, wherein the measuring step, The load balancing method of the communication system for periodically measuring the load of the first network. The method of claim 1, wherein the limit load, And a maximum acceptable load considering the packet throughput of the first mobile access means. In the load balancing method of a communication system supporting a proxy mobile internet protocol, The mobile control station may further include receiving load information of a corresponding network from at least one mobile access means; Calculating an average load index for the entire network by using the received load information; If the calculated average load index is less than a predetermined limit load index, determining a first network having the largest network load as an overload network by using the received load information; Transmitting a load balancing request message to first mobile access means designated to a first network determined as said overload network; The first mobile access means, upon receiving the load balancing request message, of the at least one mobile terminal connected to the first network, a handover target mobile terminal and a second network to which the handover target mobile terminal will handover. Determining; And And the handover target mobile terminal performs handover to the second network according to the determination result. The method of claim 4, wherein the receiving step, Load balancing method of communication system that is performed periodically. The method of claim 4, wherein the calculating step, The load balancing method of the communication system performed when the total network load determined from the received load information exceeds a predetermined limit load. The method of claim 1 or 4, wherein the determining step, And determining, as the handover target mobile terminal, the mobile terminal having the largest data request rate among the at least one mobile terminal connected to the first network. The method of claim 7, wherein the determining step, And determining the mobile terminal to be handed over, excluding a mobile terminal having a real-time service session established with the first network. The method of claim 1 or 4, wherein the determining step, Considering the load information of each of the at least one network to which the handover target mobile terminal is accessible and the signal strength of the handover target mobile terminal, the second network is selected from at least one network to which the handover target mobile terminal is accessible. The load balancing method of the communication system to determine. The method of claim 9, wherein the determining step, Transmitting a handover initiation message to each of at least one network accessible by the handover target mobile terminal; In response to transmitting the handover initiation message, receiving a handover grant message including load information from at least one network to which the handover target mobile terminal is accessible. The method according to claim 1 or 4, The first mobile access means further comprising transmitting a handover command message to the handover target mobile terminal according to the determination; The handover step, The load balancing method of the communication system performed in response to receiving the handover command message. In a communication system supporting a proxy mobile internet protocol, When at least one mobile terminal is assigned to the connected first network and the load of the first network exceeds a preset limit load, the handover target mobile terminal and the handover target movement among the connected at least one mobile terminal First mobile access means for determining a second network for the terminal to handover to; And And a handover target mobile terminal for handing over to the second network according to the determination of the first mobile access means. The method of claim 12, wherein the first mobile connection means, A communication system for periodically measuring a load of the first network. In a communication system supporting a proxy mobile internet protocol, When the average load index for the entire network calculated using the load information of the corresponding network respectively received from the at least one mobile access means is less than a predetermined limit load index, the first network load is determined using the received load information. A mobile control station for determining one network as an overload network; A handover target mobile terminal and the handover target mobile terminal among the at least one connected mobile terminal are assigned to the first network to which at least one mobile terminal is connected and receive a load balancing request message from the mobile control station. First mobile access means for determining a second network to which to hand over; And And a handover target mobile terminal for handing over to the second network according to the determination of the first mobile access means. The method of claim 14, wherein the mobile control station, And determining whether the average load index is less than the preset limit load index when the total network load determined from the received load information exceeds a preset limit load. The method of claim 12 or 14, wherein the first mobile connection means, A communication system for determining a handover target mobile terminal having a large data request rate among at least one mobile terminal connected to the first network. The method of claim 12 or 14, wherein the first mobile connection means, The second network is determined from at least one network to which the handover target mobile terminal is accessible in consideration of load information of each of the at least one network to which the handover target mobile terminal is accessible and the signal strength of the handover target mobile terminal. Communication system. The method of claim 12 or 14, wherein the handover target mobile terminal, And perform a handover to the second network in response to receiving a handover command message from the first mobile access means.

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