KR101565921B1 - A method for offering information for vertical handover and a method thereof - Google Patents

Abstract

The present invention relates to a system for providing information for handover to a heterogeneous network and a method for the same, and in particular, to a method and system for providing information for handover to a heterogeneous network, The method comprising the steps of: transmitting network information supporting the use mode to a user terminal; and performing a handover using a network supporting the frequency usage mode of the user terminal using the network information by the user terminal The present invention provides a method for providing information for handover to a heterogeneous network.

MIH, ANDSF

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information providing system for handover to a heterogeneous network,

The present invention relates to a heterogeneous network handover, and more particularly, to a system for providing information for handover to a heterogeneous network according to a frequency usage mode of a user terminal and a method therefor when handing over to a heterogeneous network.

Handover (or handoff) technology refers to a technique for automatically switching a communication channel when a mobile communication subscriber moves from one wireless communication zone to another wireless communication zone so as not to interrupt service communication.

Generally, handover refers to handover between homogeneous networks. However, in order to overcome the disadvantage of providing limited handover service within the homogeneous network in the same time with many networks of different systems, International standardization studies are underway on technologies to provide handover between heterogeneous networks. The heterogeneous handover (or vertical handover) is not a handover between base stations of the same system, for example, WiBro, but a network of a WiBro network and other systems, for example, Handover to a wireless local area network (WLAN) network based on a second generation (2G) network, a third generation (3G) network, an IEEE (Institute of Electrical and Electronics Engineers) it means.

A terminal for performing handover between heterogeneous networks supports a multiple access mode supporting various access networks. That is, the terminal supports a mode of accessing at least two of a WiBro network, a second-generation network, a third-generation network, and an IEEE 802.11-based wireless LAN network. Such a terminal will be referred to as an MMT (Multiple Mode Terminal). Meanwhile, a terminal supporting the multiple access mode may support a single-radio operation mode in which only one mode can be used at the same time, or a dual-radio operation mode in which two or more modes can be supported at the same time ) Are supported.

"Pre-registration like Forward Attachment Function (L3)" adopted by 3GPP, Mobile WiMAX, "Pre-registration (L2)" adopted by 3GPP, 3GPP2, IEEE And the "Media Independent Handover (MIH)" technology of 802.21. However, handover optimization is not possible when MIH supports single frequency use mode.

In the meantime, there are "Access Network Discovery and Selection Function (ANDSF)" as defined in 3GPP, IEEE 802.21 and "Media Independent Handover (MIH)" of IEEE 802.21 as a technology supporting dual- Technology.

As described above, since the handover technology between the heterogeneous networks according to the related art supports only one of the single-radio operation and the dual-radio operation, There is a restriction on handover to heterogeneous networks.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to overcome the above-mentioned problems of the related art by providing a user terminal supporting a multiple access mode, The present invention provides a method and system for providing information for handover to a heterogeneous network capable of performing handover to a heterogeneous network using an optimal network depending on whether or not the mobile terminal supports the use mode.

According to another aspect of the present invention, there is provided a method of providing information for handover to a heterogeneous network, the method comprising: transmitting a frequency mode of use by a user terminal to a handover controller; A step in which a controller transmits network information supporting the frequency use mode to a user terminal, and a process in which a user terminal performs a handover using a network supporting the frequency use mode of the user terminal using the network information, .

According to another aspect of the present invention, there is provided an information providing system for handover to a heterogeneous network, the system comprising: a handover controller for providing network information supporting a frequency use mode; And a user terminal for transmitting a frequency usage mode of the handover controller to a handover controller and performing a handover using a network supporting its own frequency using mode using the network information.

The foregoing is a somewhat broad summary of features and technical advantages of the present invention in order that those skilled in the art will be better able to understand it from the following detailed description of the present invention. Additional features and advantages of the present invention, which form the subject matter of the claims of the invention, in addition to those features and advantages, will be better understood from the following detailed description of the invention.

According to the present invention, the user terminal 100 supporting the multiple access mode can efficiently perform the handover to the heterogeneous network. That is, in the case of a user terminal supporting a multiple access mode, an optimal network is used in accordance with a frequency use mode (single-radio operation mode and single-radio operation mode) Handover to the heterogeneous network can be performed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a detailed description of preferred embodiments of the present invention will be described with reference to the accompanying drawings. Those skilled in the art will appreciate that the concepts and specific embodiments of the invention described below may be altered or modified in various ways to attain the objects of the invention. It will also be appreciated by those skilled in the art that the concepts and structures equivalent to those disclosed herein are not to depart from the spirit and scope of the broadest form of the invention. It should be noted that, in the drawings, reference numerals and like components are denoted by the same reference numerals and signs as possible even if they are shown in different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

1 is a view for explaining a heterogeneous network handover information providing system according to an embodiment of the present invention.

A handover information providing system according to an embodiment of the present invention includes a user equipment (UE) 100 and a vertical handover controller (VHO controller, hereinafter referred to as "handover controller 200" 200).

The user terminal 100 according to the embodiment of the present invention is a multiple mode terminal (MMT).

The multiple access mode terminal means to include two or more function modules that can access the same or different access networks. For example, one terminal may be a wireless broadband Internet (WiBro) network, a second generation (2G) network, a third generation (3G) network, an Institute of Electrical and Electronics Engineers (Wireless LAN (Local Area Network)) network, and a communication module of a standard for connection to at least two networks.

In addition, the user terminal 100 according to the embodiment of the present invention may operate in a single radio operation mode (hereinafter abbreviated as "single mode") or a dual radio operation mode (Multi-radio operation, hereinafter abbreviated as "dual mode").

In the single mode, the user terminal 100 can use only one radio frequency at a time. Therefore, at the time of handover, the user terminal 100 supporting the single radio mode can move to the target network after disconnecting from the source network. Therefore, it is difficult to avoid service disconnection. At this time, the user terminal 100 must maintain a connection with the source network until preparation for movement to the target network is completed, and the user terminal 100 must use the radio with the source network currently used to prepare for movement to the target network.

On the other hand, the dual mode can use two or more radio frequencies at the same time. Therefore, it is possible to maintain the connection with the source network and the target network until moving to the target network during the handover. That is, one frequency may be used for connection to the source network, and another frequency may be used for connection to the target network. Therefore, the handover can be performed without disconnecting the service.

In summary, the user terminal 100 supporting the single mode must disconnect from the source network and then move to the target network. Alternatively, the user terminal 100 may move to the target network supporting the dual mode and disconnect the source network.

As described above, depending on whether the user terminal 100 supports the single radio operation or the multi-radio operation, the handover to the heterogeneous network differs in its operation. Therefore, the user terminal 100 according to the embodiment of the present invention transmits a frequency using mode to the handover controller 200 to inform whether the single terminal supports the single radio operation or the multi-radio operation.

The handover controller 200 is an entity that provides information about a network necessary for handover to a heterogeneous network to a terminal, and can be located in an arbitrary core network. For example, the handover controller 200 may be an Access Network Discovery Support Function (ANDSF) or an MIH Information Server (hereinafter abbreviated as "MIH IS").

The handover controller 200 manages network resources for supporting heterogeneous network handover in a core network in which heterogeneous networks are scattered. According to an embodiment of the present invention, when network information is requested from the user terminal 100, information of all connected heterogeneous networks is transmitted to the user terminal 100.

In particular, the handover controller 200 according to an exemplary embodiment of the present invention receives a frequency operation mode of a terminal and performs a vertical handover method (HO Policy) supportable according to the received frequency usage mode, And network information that can be supported to the user terminal 100.

The user terminal 100 receiving the vertical handover method (HO Policy) and network information that can be supported from the handover controller 200 performs a vertical handover according to the received information.

More specifically, in order to perform a vertical handover, information about the network must first be obtained as a preparation for vertical handover.

Then, when the handover is initiated in the user terminal 100, an available resource check step for neighboring networks, a destination network resource preparation step according to the selection of the destination network, a connection to the layer 2 is ensured, A handover execution step of updating information, and a handover completion through a process of releasing a resource used in a previous network by notifying completion of a handover execution.

The handover process is different according to the type of the access network except for the process of acquiring the information about the network in advance. .

In the embodiment of the present invention, in the process of obtaining the network information, which is the preparation stage, the network information supporting the frequency use mode of the user terminal 100 is obtained, And performs handover.

Hereinafter, an information providing method for performing vertical handover according to the frequency use mode will be described. At this time, an embodiment according to MIH (Media Independent Handover) will be described, but the present invention is not limited thereto.

First, the protocol structure of the user terminal 100 and the handover controller 200 according to the embodiment of the present invention will be described. 2 is a diagram for explaining a protocol structure of a user terminal and a handover controller according to an embodiment of the present invention.

2, a functional structure according to a protocol according to an embodiment of the present invention includes a MIH function unit 110, 210, an MIH function unit 120, 220, and a three-layer . In addition, the user terminal 100 and the handover controller 200 include the above three layers (reference numerals 110 to 230), respectively.

Reference numerals 110, 120, and 130 denote local MIH use units, MIH function units, and interface units, and reference numerals 210, 220, and 230 denote remote MIH use units, MIH function units, Interface unit. On the other hand, the handover controller 200 is opposite to the above.

The MIH use units 110 and 210 refer to an upper layer based on the MIH function unit. The MIH uses the TCP / IP protocol and processes protocols such as MIP, FMIP, and PMIP.

The MIH function units 120 and 220 provide an interface for connection between the plurality of interface units 130 and 230 and the MIH usage units 110 and 210.

That is, the MIH function units 120 and 220 include an event service module for event information transmitted and received between the user terminal 100 and base stations of each network for media independent handover, a command service Module, and an information service module for network information.

The event service module performs an event service that locally or remotely transmits event information indicating the state change of the user terminal 100 or the handover controller 200 and receives the event information locally or remotely. The command service unit may transmit command information to the user terminal 100 or the handover controller 200 to control the local or remote user terminal 100 or the handover controller 200, And performs a command service for receiving command information from the handover controller 200 and performing control. The information service unit requests the information of the surrounding network from the user terminal 100 or the handover controller 200 to the local or remote user terminal 100 or the handover controller 200 or transmits the requested information to a local or remote user And performs an information service (Information Service) received from the terminal 100 or the handover controller 200.

The interface units 130 and 230 are composed of a physical layer and a MAC (Media Access Control) layer, which are lower layers of the respective access networks. In detail, the interfaces 130 and 230 include an 802.11 interface for standard IEEE 802.11 based wireless LAN access, an 802.16 interface for accessing a standard IEEE 802.16 based wireless wide area network (WMAN) , A cellular interface for a mobile communication network connection such as 3GPP (3rd Generation Partnership Project) or 3GPP2, and the like. The interface units 130 and 230 may have interfaces for other systems in addition to the 802.11 interface, the 802.16 interface, and the cellular interface.

Next, a method of providing network information according to an embodiment of the present invention will be described. Here, the network information includes frequency use mode information.

First, a method for obtaining network information according to the performance search procedure according to an embodiment of the present invention will be described. 3 is a view for explaining a method of providing network information according to an embodiment of the present invention.

3, the local MIH using unit 110 and the MIH function unit 120, and the remote MIH function unit 210 and the MIH using unit 220 are shown.

The mediator-independent event service receives a link event terminated in the MIH function unit 120 and a link event terminated in the MIH function unit 120 from the entity generating the event in the lower layers (MIH Event), which is spread over three layers. Link events and MIH events are divided into two categories according to the propagation area.

Events are originated from a local event source and are transmitted upward from the local MIH function unit 120 or the MIH function unit 320 to the upper layers 110. This event is called a local event and occurs from a remote event source The event is transmitted to the remote MIH function unit 220 and is transmitted from the remote MIH function unit 220 to the local MIH function unit 120. This event is a remote event It is called.

In FIG. 3, the user terminal 100 transmits its own frequency mode operation to the network through a performance search message (MIH capability discovery).

That is, the user terminal 100 transmits a performance search message to the network informing its own frequency usage mode through the performance search message. Here, the network may be a local or remote MIH function unit and an MIH usage unit 110, 120, 210, 220. In particular, the remote MIH function unit 210 and the use units 210 and 220 may be the handover controller 200. Accordingly, the handover controller 200 receives the performance request search message and transmits the frequency usage mode supported by the neighboring network to the user terminal 100 according to the received performance request search.

The search message has the following structure. Table 1 is for explaining MIH capability discovery according to an embodiment of the present invention.

Name  Type Description SourceIdentifier MIHF_ID This identifies the invoker of this primitive, which is a remote MIHF. LinkAddressList LIST (NET_TYPE_ADDR) (Optional) A list of network types and link address pairs on the remote MIHF. SupportedMIHEventList MIH_EVT_LIST (Optional) List of supported events on the remote MIHF. SupportedMIHCommandList MIH_CMD_LIST (Optional) List of supported commands on the remote MIHF. SupportedISQueryTypeList MIH_IQ_TYPE_LST (Optional) List of supported MIIS query types on the remote MIHF. SupportedTransportList MIH_TRANS_LST (Optional) List of supported transport types on the remote MIHF. SupportedModeOperationList MIH_MO_List (Optional) List of supported modes Operation Types on the remote MIHF MBBHandoverSupport LIST (MBB_HO_SUPP) (Optional) This is used to indicate if a make before break handover is supported on the remote MIHF. Break before handover is always supported.

As shown in Table 1, the MIH capability discovery includes fields of "SourceIdentifier", "LinkAddressList", "Supported MIHEventList", "Supported MIHCommandList", "SupportedISQueryTypeList", "SupportedTransportList", and "MBBHandoverSupport". In particular, according to an embodiment of the present invention, a field "SupportedModeOperationList"

This "SupportedModeOperationList" field contains information on the frequency usage mode of the user terminal 100. [ That is, the user terminal 100 includes information on whether the user terminal 100 is a single-radio operation or a multi-radio operation.

The user terminal 100 starts preparation for performing a handover when the state of a link connected to the serving network is changed. The link state is determined as to whether or not the link parameter value exceeds a threshold value. If the link parameter value exceeds the reference value, it is determined that the link state has changed. Since the link status changes here, it means that the receiving intensity of the connected link is weak. Therefore, the user terminal 100 confirms the surrounding network information such as the receiving strength of another network from the serving serving network, And performs an operation to perform handover to another network in an optimal state for performing the handover.

At this time, according to the embodiment of the present invention, the user terminal 100 collects information of a network considering its own frequency usage mode. In FIG. 3, this information collection uses a capability discovery procedure.

3, the MIH using unit 110 of the user terminal 100 transmits a performance search request message (MIH capability discovery request) as described in Table 1 to a local MIH function unit 120, and receives an MIH capability discovery response from the MIH function unit in step S303. Accordingly, the user terminal 100 can know whether the local MIH function unit 120 supports its frequency use mode.

In step S305, S307, and S309, the MIH using unit 110 of the user terminal 100 transmits an MIH capability discovery request to the local MIH function unit 120 and the remote MIH function unit 220 To the remote MIH usage unit 210 via the Internet. The remote MIH user 210 receives the MIH capability discovery response and transmits the MIH capability discovery response to the MIH user terminal 110 of the user terminal 100 through steps S311, S313, and S315. Accordingly, the user terminal 100 can know whether the wireless MIH function unit 220 supports its frequency use mode.

As described above, the user terminal 100 may perform a vertical handover to a network supporting a frequency use mode supported by itself through a performance search procedure.

We have previously described how to obtain network information through a capability discovery procedure. Hereinafter, a method of obtaining network information according to a Get information procedure will be described. 4 is a view for explaining a method of providing network information according to another embodiment of the present invention.

The local MIH usage unit and the MIH function units 110 and 120, the remote MIH function unit and the MIH usage units 210 and 220 are shown in FIG. Here, the local MIH using unit and the MIH function units 110 and 120 may be the user terminal 100 and the remote MIH function unit and the MIH use units 210 and 220 may be the handover controller 200 . As described above, it is referred to as a local event (service) to send and receive messages in the local MIH use unit and the MIH function units 110 and 120, and to send and receive messages to the local and remote nodes 110, 120, 210 and 220 The process is called a remote event (service).

The user terminal 100 starts preparation for performing a handover when the state of a link connected to the serving network is changed. The link state is determined as to whether or not the link parameter value exceeds a threshold value. If the link parameter value exceeds the reference value, it is determined that the link state has changed. Since the link status changes here, it means that the receiving intensity of the connected link is weak. Therefore, the user terminal 100 confirms the surrounding network information such as the receiving strength of another network from the serving serving network, And performs an operation to perform handover to another network in an optimal state for performing the handover.

At this time, according to the embodiment of the present invention, the user terminal 100 collects information of a network considering its own frequency usage mode. In FIG. 4, this information collection uses a Get information procedure.

Referring to FIG. 4, as the state of a connected link is changed, the local MIH using unit 110 determines to collect neighboring network information for handover in step S401, and in step S403, MIH_Get_info.request) to the local MIH function unit 120.

Herein, the information collection request message includes the frequency usage mode information of the user terminal 100. In step S405, the local MIH function unit 120 generates network information for the networks supporting the corresponding frequency use mode. Then, in step S407, the local MIH function unit 120 transmits the previously created network information to the local MIH use unit 120. [

Meanwhile, the local MIH using unit 110 decides to collect neighboring network information for handover in step S409. To this end, the local MIH using unit 110 transmits an information collection request message (MIH_Get_info.request) to the local MIH function unit 120 . Then, in step S413, the MIH function unit 120 transmits an information collection request message to the remote MIH function unit 220. [ At this time, the transmitted information collection request message is transmitted as a request frame according to the network.

Upon receipt of the information collection request message, the remote MIH function unit 220 delivers the message to the remote MIH usage unit 210 in step S415. Then, in step S417, the remote MIH using unit 220 creates network information for networks supporting the frequency use mode. The local MIH function unit 120 then transmits network information to the local MIH usage unit 110 via the remote MIH function unit 220 and the local MIH function unit 120 in steps S419, S421, and S423.

4, when the local entities 110 and 120 are the user terminal 100 and the remote entities 210 and 220 are the handover controller 200, the user terminal 100 is connected to the handover controller 200, (MIH_Get_Information.request) requesting network information to the mobile station.

Further, the MIH_Get_Information.request message is transmitted from the user terminal 100 to request information related to the specific interface, the attributes of the network interface, and the overall network capability from the network.

Then, the handover controller 200 transmits a response message (MIH_Get_Information.reponse) to the user terminal 100 in response to the received network information request message. The response message includes network information supporting the frequency usage mode of the user terminal 100. [ Accordingly, the user terminal 100 can perform a vertical handover by selecting a network according to a frequency usage mode that the user terminal 100 uses.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments, but is capable of various modifications within the scope of the invention. Therefore, the scope of the present invention should not be limited by the illustrated embodiments, but should be determined by the scope of the appended claims and equivalents thereof.

1 is a diagram for explaining a heterogeneous network handover information providing system according to an embodiment of the present invention;

2 illustrates a protocol structure of a user terminal and a handover controller according to an embodiment of the present invention.

3 is a view for explaining a method of providing network information according to an embodiment of the present invention;

4 is a view for explaining a method of providing network information according to another embodiment of the present invention;

Claims (14)

A method for providing information for handover to a heterogeneous network, Transmitting a message including a frequency usage mode of the user terminal to a handover controller; Transmitting, by the handover controller, a response message including network information supporting the frequency use mode to a user terminal; And performing a handover to a network supporting a frequency use mode of the user terminal using the network information by the user terminal. 1. An information providing system for handover to a heterogeneous network, A handover controller for receiving network information supporting a frequency use mode from a user terminal and transmitting network information supporting the frequency use mode to the user terminal; And And the user terminal performing handover to a network supporting its own frequency using mode using the network information received from the handover controller. A method for handover between heterogeneous networks of a terminal, Transmitting a message including its own frequency usage mode to a handover controller; Receiving a response message including network information supporting the frequency use mode from the handover controller; And And performing a handover to a network supporting the frequency use mode based on the network information. 4. The method of claim 3, Wherein the information includes information indicating whether the terminal is a single mode mode or a multi mode mode. 4. The method according to claim 3, And a handover method and network identification information supporting the frequency use mode. An apparatus of a terminal for performing heterogeneous network handover, An event service module for communicating with at least one network node; And The method comprising: transmitting a message including its own frequency usage mode to a handover controller, receiving a response message including network information supporting the frequency usage mode from the handover controller, And a command service module for controlling the handover to the network supporting the handover. 7. The method of claim 6, And information indicating whether the terminal is a single mode or a multi mode. 7. The method according to claim 6, And a handover method and network identification information supporting the frequency use mode. A method for supporting inter-network handover of a handover controller, Receiving a message including a frequency use mode of the terminal from the terminal; Transmitting a response message including network information supporting the frequency use mode to the terminal based on the frequency use mode of the terminal, Wherein the network information is used for performing a handover from the terminal to a network supporting the frequency use mode. 10. The method of claim 9, Wherein the information includes information indicating whether the terminal is a single mode mode or a multi mode mode. 10. The method according to claim 9, And a handover method and network identification information supporting the frequency use mode. 1. An apparatus of a handover controller supporting heterogeneous network handover, An event service module for communicating with at least one network node; And A command service for receiving a message including the frequency use mode of the terminal from the terminal and transmitting a response message including network information supporting the frequency use mode to the terminal based on the frequency use mode of the terminal Module, Wherein the network information is used for performing handover from the terminal to a network supporting the frequency use mode. 13. The method of claim 12, And information indicating whether the terminal is a single mode or a multi mode. 13. The method according to claim 12, And a handover method and network identification information supporting the frequency use mode.

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