KR100836136B1 - Apparatus and method for hanodver between different communication systems - Google Patents

Abstract

An apparatus and a method for handover between different communication systems are provided to enable an MS having multi-interfaces to perform handover from an IEEE(Institute of Electrical and Electronics Engineers) 802.16e communication system to the different network systems, thereby receiving wireless communication services seamlessly and improving the quality of the wireless communication services. An MS(Mobile Station)(310) receives messages including handover information for different networks from a BS(Base Station1)(320) and measures the intensity of a signal(a,b). The BS transmits an HO(Handover)_notification_request message to a core network(330)(e,e'). The core network transmits the messages to BS2 or AP(Access Point)(340,350) capable of handover respectively(f,f'). The BS2 or the AP transmits an HO_notification_response message to the core network(g,g'). The core network includes handover target information into the HO_notification_response message and transmits the HO_notification_response message(i). The BS receives the HO_notification_response message, includes information about the determined target into an MOB_BSHO_RSP(Mobile_Base Station Handover_Response) message, and transmits the MOB_BSHO_RSP message to the MS(j). The MS transmits an MOB_HO-IND(Mobile_Handover Indication) message included into the HO_notification_response message to the BS and performs handover(l).

Description

Apparatus and method for handover between heterogeneous communication systems {APPARATUS AND METHOD FOR HANODVER BETWEEN DIFFERENT COMMUNICATION SYSTEMS}

1 is a diagram illustrating a user terminal request handover process using a downlink channel state message (DCD) in a conventional IEEE 802.16e communication system.

2 is a diagram illustrating a base station request handover process using a downlink channel status message (DCD) in a conventional IEEE 802.16e communication system;

3 is a diagram illustrating a user terminal request handover process using a downlink channel state message (DCD) from an IEEE 802.16e communication system to a heterogeneous communication system according to an embodiment of the present invention;

4 is a flowchart illustrating a handover process of a user terminal in a user terminal request handover using a downlink channel state message (DCD) from an IEEE 802.16e communication system to a heterogeneous communication system according to an embodiment of the present invention;

5 is a flowchart illustrating a handover process of a serving base station in a user terminal request handover using a downlink channel state message (DCD) from an IEEE 802.16e communication system to a heterogeneous communication system according to an embodiment of the present invention;

6 is a flowchart illustrating a handover process of a core network in a user terminal request handover using a downlink channel state message (DCD) from an IEEE 802.16e communication system to a heterogeneous communication system according to an embodiment of the present invention;

7 is a flowchart illustrating a handover process of a target base station or an access point in a user terminal request handover using a downlink channel state message (DCD) from an IEEE 802.16e communication system to a heterogeneous communication system according to an embodiment of the present invention;

8 illustrates a base station request handover process using a downlink channel state message (DCD) from an IEEE 802.16e communication system to a heterogeneous communication system according to an embodiment of the present invention;

9 is a flowchart illustrating a handover process of a user terminal in a base station request handover using a downlink channel state message (DCD) from an IEEE 802.16e communication system to a heterogeneous communication system according to an embodiment of the present invention;

10 is a flowchart illustrating a handover process of a serving base station in a base station request handover using a downlink channel state message (DCD) from an IEEE 802.16e communication system to a heterogeneous communication system according to an embodiment of the present invention;

11 is a block diagram illustrating a user terminal, an IEEE 802.16e communication system base station, a core network, and a target base station or access point according to an embodiment of the present invention;

12 illustrates a downlink channel state message (DCD) according to an embodiment of the present invention;

13 illustrates a MOB_MSHO-REQ message according to an embodiment of the present invention;

14 illustrates a MOB_BSHO-REQ message according to an embodiment of the present invention;

15 illustrates a MOB_BSHO-RSP message according to an embodiment of the present invention, and

16 illustrates a MOB_HO-IND message according to an embodiment of the present invention.

The present invention relates to handover between heterogeneous networks, and more particularly, to an apparatus and a method for supporting a handover of a user terminal to a heterogeneous network in a broadband wireless access communication system.

In the 4th Generation (hereinafter referred to as '4G') communication system, providing users with services having various quality of service (QoS) with a transmission rate of about 100 Mbps. Active research is in progress. In particular, in the current 4G communication system, broadband wireless access such as a wireless local area network (LAN) system and a wireless urban area network (MAN) system Access: Research is being actively conducted to support high-speed services in the form of guaranteeing mobility and quality of service (QoS) in a BWA communication system. In addition, the representative communication system is a broadband wireless access communication system, and Institute of Electrical and Electronics Engineers (IEEE) 802.16d communication system and IEEE 802.16e communication system are representatively used. Wimax or Wibro use the IEEE 802.16d communication system technology and the IEEE 802.16e communication system technology.

The IEEE 802.16d communication system and the IEEE 802.16e communication system are orthogonal frequency division multiplexing (OFDM) for supporting a broadband transmission network on a physical channel of the wireless MAN system. (Orthogonal Frequency Division Multiple Access (hereinafter referred to as 'OFDMA')). The IEEE 802.16d communication system is a system in which a user terminal is fixed, that is, a state in which mobility is not considered at all, and only a single cell structure is considered, whereas the IEEE 802.16e communication system is configured to provide the user with the IEEE 802.16d communication system. The system considers the mobility of the terminal.

The user terminal is movable, and there is a situation in which it is necessary to change the connected base station during the movement. In this case, we change to another base station. This is called handover.

The handover is a heterogeneous network that is not a handover between heterogeneous networks (VHO: Vertical Handover, for example, an IEEE 802.16e communication system), which is a handover between the same networks and a different type of communication system. (Handover to 2G, 2.5G, 3G, 3.5G, IEEE 802.11x)).

1 is a diagram illustrating a user terminal request handover process using a downlink channel state message (DCD) in an existing IEEE 802.16e communication system.

Referring to FIG. 1, a user station (MS) 110 may be configured from a base station 1 (BS) 120 or another base station (base station 2 130, base station 3 140) in the vicinity. DL-MAP message including base station information and channel status, downlink channel status message (DCD: Downlink Channel Descriptor), uplink channel status message (UCD: Upink Channel Descriptor) (step a) and receive signal size Measure (step b).

Then, when the user terminal 110 needs to handover, the user terminal 110 prepares a handover target list and includes it in the terminal handover request message (MOB_MSHO-REQ) to transmit to the base station 1 120 (step c). The base station 1 120 generates a list of base stations capable of handover from the list transmitted by the user terminal 110 (step d).

Subsequently, the base station 1 120 transmits a handover notification request message HO_notification_request for requesting information required for handover to a handover capable base station (base station 2 130 and base station 3 140) (step e). .

The base station capable of handover (base station 2 (130), base station 3 (140)) checks whether handover is possible for the user terminal (110) and checks the result of the handover as a response message to the handover notification request message. The message is included in the notification response message HO_notification_response and transmitted (step f).

The base station 1 120 receives the handover notification response message to determine the base station to be handed over and includes the result in the handover response message MOB_BSHO-RSP and transmits the result to the user terminal 110 (step g). ).

Thereafter, the user terminal 110 transmits a handover message (MOB_HO-IND) to the base station 1 (120) to handover to the base station 3 (140) included in the handover response message (step h). Perform

The base station 1 (120) receiving the handover message releases the connection with the user terminal (110).

Thereafter, the user terminal 110 receives the DL-MAP message, the downlink channel status message, and the uplink channel status message after handing over to the base station 3 140 (step j), and the base station 3 140. And ranging process (steps k and l).

2 is a diagram illustrating a base station request handover process using a downlink channel state message (DCD) in an existing IEEE 802.16e communication system.

Referring to FIG. 2, the user terminal 210 includes a DL-MAP message including information on the base stations from base station 1 220 or other base stations (base station 2 230 and base station 3 240) in the vicinity. Receive the downlink channel status message, the uplink channel status message message (step a) and measure the signal size (step b).

The user terminal 210 may measure the signal size and the channel state and transmit it to the base station 1 220.

Subsequently, the base station 1 220 receives the signal size and the channel state from the user terminal 210, and when the user terminal 210 needs to handover, a base station handover is made by creating a target list capable of handover. Included in the request message (MOB_BSHO-REQ) and transmitted to the user terminal 220 (step c), the user terminal 220 is a base station list (base station 2) that can be handed over from the list transmitted by the base station 1 (220) In step 230, base station 3 (240) is created and transmitted to base station 1 (220) in a handover message (MOB_HO-IND) (step d).

Subsequently, the base station 1 220 transmits a handover notification request message for requesting information necessary for handover to a base station capable of handover (base station 2 230 and base station 3 240) transmitted by the user terminal 210 ( HO_notification_request) is transmitted (step e).

The handoverable base station (base station 2 (230), base station 3 (240)) checks whether handover is possible for the user terminal (210) and checks the result of the handover as a response message to the handover notification request message. The message is included in the notification response message HO_notification_response and transmitted (step f).

The base station 1 220 receives the handover notification response message to determine a base station to be handed over (base station 3 240) and transmits a handover confirmation message HO_notification_confirm to the base station 3 240 (step g). ).

Subsequently, the base station 1 220 includes the information of the base station (base station 3 240) to be handed over in the handover response message MOB_BSHO-RSP and transmits the information to the user terminal 210 (step h).

Thereafter, the user terminal 210 performs a handover to the base station 3 240 included in the handover response message.

Thereafter, the connection between the base station 1 220 and the user terminal 210 is terminated (step i).

Thereafter, the user terminal 210 receives the DL-MAP message, the downlink channel status message, and the uplink channel status message after handing over to the base station 3 240 (step j). And ranging process (steps k and l).

In the IEEE 802.16e communication system, a procedure for handover between the same networks has been defined so far, but the procedure is not defined except for the possibility of handoff between heterogeneous networks. This means that even if a user terminal can use multiple wireless communication protocols, continuous data service becomes unavailable when moving to an area where IEEE 802.16e communication is not possible (that is, a WLAN or 2G / 2.5G / 3G / 3.5G service only area). Indicates.

Accordingly, in order to support two or more wireless communication modules in a user terminal and to support handover between heterogeneous networks in a flexible manner, a technology for supporting the IEEE 802.16e communication system is required.

An object of the present invention is to provide an apparatus and method for handover between heterogeneous communication systems.

Another object of the present invention is to provide an apparatus and method for enabling handover from an IEEE 802.16e communication system to another communication system.

It is still another object of the present invention to provide an apparatus and method capable of providing a seamless service to a user by enabling handover from an IEEE 802.16e communication system to another communication system.

It is still another object of the present invention to provide an apparatus and method for providing a MAC layer message for enabling handover from an IEEE 802.16e communication system to another communication system.

According to a first aspect of the present invention for achieving the above object, in a method for requesting handover of a user terminal from a broadband wireless access communication system to a heterogeneous communication system, a heterogeneous communication system supported by a core network from a base station by the user terminal Receiving a message including a handover type and measuring a signal size and if the measurement result indicates the need for handover to a heterogeneous communication system, the UE handover request including a list of heterogeneous communication systems capable of handover by the user terminal Transmitting a message to the base station, receiving a handover response message including information on a target that the user terminal can actually handover from the base station, and transmitting a handover message including information on the target.In that it comprises a static features.

According to a second aspect of the present invention for achieving the above object, a base station request handover method of a user terminal from a broadband wireless access communication system to a heterogeneous communication system, the heterogeneous communication system that the user terminal is supported by the core network from the base station Receiving a message including a handover type, measuring a signal size, and transmitting the signal to the base station; and receiving, from the base station, a base station handover request message including information on a target to which the user terminal can actually handover; And transmitting a handover message including information on the target to the base station and receiving a handover response message including information on the target from the base station.

 According to a third aspect of the present invention, a communication system supporting a terminal request handover from a broadband wireless access communication system to a heterogeneous communication system includes a heterogeneous communication system handover type supported by a core network. When the message is received, the signal size is measured, and the result indicates the need for handover to the heterogeneous communication system, a terminal handover request message including a list of heterogeneous communication systems capable of handover is transmitted, and the user terminal is actually capable of handover. A user terminal for receiving a handover response message including information on a target and transmitting a handover message including information on the target, and a heterogeneous communication system handover type supported by a core network to the user terminal. Send a message, The user terminal receives a terminal handover request message including a list of heterogeneous communication systems capable of handover and sends a handover notification request message included in the heterogeneous communication system list and directed to a target capable of handover by the core network. Send to the network and receive a handover notification response message in response to include the information on the included target in the handover response message and transmit the information to the user terminal, and receives a handover message including the information on the target, Receives a handover notification request message from the base station that transmits a handover notification message to the core network and to the targets to which the core network and the user terminal are capable of handover from the base station, and transmits the handover notification message to the targets, respectively, in response to God A handover that receives a handover notification response message including a call state to determine a target and transmits a handover notification response message including information of the determined target to the base station and informs the handover of the user terminal from the base station. And a target network for receiving a notification message and transmitting the handover notification response message including the signal state of the target by receiving a handover notification request message from the core network and transmitting the target network to the target. It features.

According to a fourth aspect of the present invention for achieving the object, a communication system supporting a base station request handover from a broadband wireless access communication system to a heterogeneous communication system, comprising a type of heterogeneous communication system handover supported by a core network Sending a message to the user terminal and receiving the measured signal size and channel state from the user terminal, if the size measurement result indicates the need for handover to a heterogeneous communication system, the user terminal is determined to perform the handover to the heterogeneous communication system Transmits a handover notification request message to the core network to the targets that can actually handover to the core network, receives a handover notification response message in response, and provides the base station handover request message with information about the target included in the handover notification response message. Embed in the above A base station transmitting the user handover response message including information on the target from the user terminal and transmitting a handover notification message directed to the target to the core network and the core network and the user from the base station; The terminal receives a handover notification request message directed to the targets capable of handover and transmits each of the targets to the targets, and in response, receives a handover notification response message including respective signal states, determines a target, and determines the target information. A core network and a core network configured to transmit a handover notification response message including a handover notification message to the target station and to receive a handover notification message indicating a handover to the user terminal from the base station; Receive a message including a heterogeneous communication system handover type supported by the core network from the target and the base station for receiving a drawover notification request message and transmitting a handover notification response message including the signal state of the target to the core network. Measure a signal size and transmit the signal to the base station, and receive a base station handover request message including information on a target that the user terminal can actually handover from the base station, and receive a handover message including information on the target. And a user terminal transmitting to the base station and receiving a handover response message including information on the target from the base station.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

Hereinafter, an apparatus and method for handover between heterogeneous communication systems will be described.

In the present invention, the downlink channel state message (DCD), the UE handover request message (MOB_BSHO-REQ), the base station handover request message (MOB_MSHO-REQ), and the handover response message that are used for handover in the existing IEEE 802.16e standard. (MOB_BSHO-RSP) and handover message (MOB_HO-IND) are modified and used.

First, a downlink channel state message (DCD) field is added and supplemented as shown in FIG. 12 to support heterogeneous network handover. In order to express the type of heterogeneous network that can be supported in the core network, “HO type support” is added as shown in FIG. 12. The handover types shown in bits 3 through 7 have been added to support heterogeneous network handover.

Second, the UE handover request message (MOB_MSHO-REQ) field is added and supplemented as shown in FIG. 13 to support heterogeneous network handover. The newly added "N_VHO_BS_Index" field indicates the number of heterogeneous networks that can be supported by the current user terminal except for the IEEE 802.16e communication system among the types of networks defined in "HO type support" of the downlink channel status message (DCD). The newly added "VHO_BS_Index" field indicates a value defined in "HO type support" of the downlink channel status message (DCD) to indicate the type of network capable of supporting heterogeneous network handover. In addition, the newly added "VHO_Signal_Strength_Status" field indicates the core network and the RF signal status value defined for heterogeneous network handover.

Third, the base station handover request message (MOB_BSHO-REQ) field is added and supplemented as shown in FIG. 14 to support heterogeneous network handover. Increase the existing mode field from 3 bits to 4 bits and add the value "0b0001: VHO request". In case of "VHO request", "VHO BS type" (indicates the value defined in "HO type support" of downlink channel status message (DCD) to indicate the type of network capable of supporting heterogeneous network handover), "VHO BS Info "(connection information of the target determined for heterogeneous network handover), and" VHO BS RsvInfo "(additional information of the target determined for heterogeneous network handover) are added. The values of the "VHO BS Info" and the "VHO BS RsvInfo" may be additionally inserted in some cases.

Fourth, the handover response message (MOB_BSHO-RSP) field is added and supplemented as shown in FIG. 15 to support heterogeneous network handover. Increase the existing mode field from 3 bits to 4 bits and add the value "0b0001: VHO request". If "VHO request", "VHO BS type" (indicates the value defined in "HO type support" of the downlink channel status message (DCD) to indicate the type of network that can support heterogeneous network handover), "VHO BS Info" (connection information of the target determined for heterogeneous network handover), and "VHO BS RsvInfo" (additional information of the target determined for heterogeneous network handover) are added. The values of the "VHO BS Info" and the "VHO BS RsvInfo" may be additionally inserted in some cases.

Finally, the handover message (MOB_HO-IND) field is added and supplemented as shown in FIG. 16 to support heterogeneous network handover. Increase the existing mode field from 2 bits to 3 bits and add the value "0b001: VHO". For heterogeneous network handover, "VHO BS type" (indicates the value defined in "HO type support" in the downlink channel status message (DCD) to indicate the type of network capable of supporting heterogeneous network handover), "VHO RsvInfo "(additional information of heterogeneous network handover) is added. The values of the "VHO BS Info" and the "VHO RsvInfo" may be additionally inserted in some cases.

12 to 16 illustrate the parts added in the present invention to the existing message.

The heterogeneous network handover procedure proposed in the present invention will be described in FIGS. 3 and 8 below.

3 is a diagram illustrating a user terminal request handover process using a downlink channel state message (DCD) from an IEEE 802.16e communication system to a heterogeneous communication system according to an embodiment of the present invention.

Referring to FIG. 3, it is similar to a handover procedure between homogeneous networks proposed in the existing IEEE 802.16e communication system. However, as described above, the modified message for heterogeneous network handover support is used.

The user terminal 310 includes a DL-MAP message, a downlink channel state message (DCD), and an uplink channel state message (UCD) including information on the base station and handover information on the heterogeneous network from the base station 1 320. Receive (step a) and measure the signal size (step b) and determine whether to perform a handover.

Then, when the user terminal 110 needs to perform a handover, the user terminal 110 prepares a target list to be handed over and includes it in the terminal handover request message (MOB_MSHO-REQ) and transmits it to the base station 1 320 (step c). The base station 1 320 generates a list of base stations capable of handover from the list transmitted by the user terminal 310 (step d).

The list creation process also includes the base stations or access points 340 and 350 of the heterogeneous network system.

Subsequently, the base station 1 120 includes a list prepared for transmission to the handoverable base stations 340 and 350 or the access points 340 and 350, respectively, and a handover notification request message requesting information required for handover ( HO_notification_request) is transmitted to the core network 330 (step e and e ').

The core network 330 sends the messages to the handoverable base stations 340 and 350 or the access points 340 and 350, respectively (steps f and f ').

Thereafter, the handoverable base station 340, 350 or the access point 340, 350 includes a signal state in the handover notification response message HO_notification_response to transmit to the core network 330 (g and g '). The core network 330 determines the target (base station 340 or access point 340) to handover based on this (step h).

Thereafter, the core network 330 includes the determined information about the target in a handover notification response message HO_notification and transmits it (step i).

The base station 1 320 receives the handover notification response message and includes information on the target (base station 340 or access point 340) determined in the handover response message MOB_BSHO-RSP. Transmit to step 310 (step j).

A heterogeneous network handover is then performed from the core network 330 (step k).

The user terminal 310 transmits a handover message (MOB_HO-IND) to the base station 1 (320) to handover to the target (base station 340 or access point 340) included in the handover response message. (Step l) and perform a handover.

Subsequently, the base station 1 320 transmits a handover notification message HO_indication that the user terminal 310 hands over to the core network 330 (step m), and the core network 330 sends the hand. The over notification message HO_indication is transmitted to the target (base station 340 or access point 340) (step n).

Thereafter, the user terminal 110 receives a message about registration and connection at the target and transmits a response to complete the handover process (step o).

4 is a flowchart illustrating a handover process of a user terminal in a user terminal request handover using a downlink channel state message (DCD) from an IEEE 802.16e communication system to a heterogeneous communication system according to an embodiment of the present invention.

Referring to FIG. 4, a user terminal may include a DL-MAP message, a downlink channel state message (DCD), and an uplink channel state message (UCD) including information on the base station and handover information on a heterogeneous network from a base station. In step 410, the signal size is measured and whether handover is performed is determined (step 420).

Thereafter, a target list to be handed over is created and included in a terminal handover request message (MOB_MSHO-REQ) including information on a heterogeneous network and transmitted to the base station (step 430), and from the list of user terminals from the base station. The base station receives a handover response message (MOB_BSHO-RSP) including a list capable of supporting handover (step 440).

Thereafter, the user terminal determines a target target to be handed over from the list included in the handover response message (MOB_BSHO-RSP) (step 450) and transmits a handover message (MOB_HO-IND) including information on the determined target. Transmit to the base station (step 460) and perform a handover.

Then, the algorithm according to the present invention is terminated.

5 is a flowchart illustrating a handover process of a serving base station in a user terminal request handover using a downlink channel state message (DCD) from an IEEE 802.16e communication system to a heterogeneous communication system according to an embodiment of the present invention.

Referring to FIG. 5, the base station transmits a DL-MAP message, a downlink channel state message (DCD), and an uplink channel state message (UCD) including information on the base station and handover information on a heterogeneous network. (Step 510).

Thereafter, the terminal receives a handover request message (MOB_MSHO-REQ) including a list of heterogeneous networks to be handed over from the user terminal (step 520), and creates a target list capable of handover from the list transmitted by the user terminal (530). step).

Subsequently, a handover notification request message (HO_notification_request) including a list prepared for transmission to a handovered heterogeneous network base station or an access point respectively and requesting information necessary for handover is transmitted to a core network (step 540). In step 550, a handover notification response message HO_notification including information on a target determined as a handover target is received.

Thereafter, the determined information about the target is included in the handover response message (MOB_BSHO-RSP) and transmitted to the user terminal (step 555). In step 560, a handover message (MOB_HO-IND) for handing over to the target is received from the user terminal.

Thereafter, a handover notification message HO_indication is transmitted to the core network (step 570), and the algorithm according to the present invention is terminated.

6 is a flowchart illustrating a handover process of a core network in a user terminal request handover using a downlink channel state message (DCD) from an IEEE 802.16e communication system to a heterogeneous communication system according to an embodiment of the present invention.

Referring to FIG. 6, the core network receives a handover notification request message (HO_notification_request) including information on a base station or an access point capable of handover in a heterogeneous network (step 610), and the handoverable base station Or transmit to the access point, respectively (step 620).

Thereafter, a handover notification response message (HO_notification_response) including a signal state is received from the handoverable base station or access point (step 630), and a target to be handed over is determined based on this (step 640).

Thereafter, the determined information about the target is included in the handover notification response message HO_notification and transmitted to the base station (step 650).

Thereafter, a handover notification message (Vertical_HO_indication) indicating handover is received from the base station (step 660), and a handover notification message (Vertical_HO_indication) is transmitted to the target (step 670).

Then, the algorithm according to the present invention is terminated.

7 is a flowchart illustrating a handover process of a target base station or an access point in a user terminal request handover using a downlink channel state message (DCD) from an IEEE 802.16e communication system to a heterogeneous communication system according to an embodiment of the present invention. .

Referring to FIG. 7, the target base station or access point receives a handover notification request message (HO_notification_request) from the core network (step 710).

Thereafter, the signal state is included in the handover notification response message HO_notification_response and transmitted to the core network (step 720).

Then, the target base station or access point receives a handover notification message (Vertical_HO_indiacation) that the user terminal is to perform a handover (step 730) and terminates the algorithm according to the present invention.

8 is a diagram illustrating a base station request handover process using a downlink channel state message (DCD) from a IEEE 802.16e communication system to a heterogeneous communication system according to an embodiment of the present invention.

Referring to FIG. 8, it is similar to the handover procedure between homogeneous networks proposed in the existing IEEE 802.16e communication system. However, as described above, the modified message for heterogeneous network handover support is used.

The user terminal 810 may include a DL-MAP message and a downlink channel status message including information on the base station and handover information on the heterogeneous network from the IEEE 802.16e base station 820 (hereinafter, referred to as base station 1). DCD), and receives an uplink channel status message (UCD) (step a).

The user terminal 810 may measure the signal size and the channel state and transmit it to the base station 1 820.

Subsequently, the base station 1 820 receives the signal size and the channel state from the user terminal 810, and when the user terminal 810 needs to handover, prepares a base station list capable of handover (step b). ). The list creation process includes base stations 840 and 850 or access points 840 and 850 of heterogeneous network systems.

Subsequently, the base station 1 120 includes a list prepared for transmission to the handoverable base stations 840 and 850 or the access points 840 and 850, respectively, and a handover notification request message requesting information required for handover. (HO_notification_request) is sent to the core network 830 (steps c and c ').

The core network 830 sends the messages to the handoverable base stations 840 and 850 or access points 840 and 850, respectively (d and d 'steps).

Thereafter, the handoverable base station 840 or 850 or the access point 840 or 850 includes the signal strength in the handover notification response message HO_notification_response and transmits the signal to the core network 830 (e and e '). Based on this, the core network 830 determines a target (base station 840 or access point 840) to be handed over (step f).

Thereafter, the core network 830 includes the information on the determined target (base station 840 or access point 840) in the handover notification response message HO_notification and transmits the information to the base station 1 820 (g). step).

Subsequently, the base station 1 820 includes the information on the determined target (base station 840 or access point 840) in a base station handover request message (MOB_BSHO-REQ) and transmits the information to the user terminal 820. (Step h), the user terminal 820 transmits a handover message (MOB_HO-IND) to the base station 1 820 indicating that it is to handover to the target (base station 840 or access point 840). (Step i).

Thereafter, the base station 1 820 transmits a handover response message (MOB_BSHO-RSP) to the user terminal 810 as a response message.

A heterogeneous network handover is then performed from the core network 330 (step k).

Subsequently, the base station 1 820 transmits a handover notification message HO_indication to the core network 830 that the user terminal 810 performs a handover (step l), and the core network 830 The handover notification message HO_indication is transmitted to the target (base station 840 or access point 840) (step m).

Thereafter, the user terminal 810 receives a message about registration and connection at the target (base station 840 or access point 840) and transmits a response to complete a handover process (step n).

9 is a flowchart illustrating a handover process of a user terminal in a base station request handover using a downlink channel state message (DCD) from an IEEE 802.16e communication system to a heterogeneous communication system according to an embodiment of the present invention.

Referring to FIG. 9, a user terminal may include a DL-MAP message, a downlink channel state message (DCD), and an uplink channel state message (UCD) including information on the base station and handover information on a heterogeneous network from a base station. Receive (step 910).

The user terminal may measure the signal size from the received message.

Thereafter, if the base station handover request message (MOB_BSHO-REQ) including the handover target heterogeneous network base station or access point information is received from the base station (step 920). The target handover target is determined from the information (step 930), and a handover message (MOB_HO-IND) including information on the target is transmitted to the base station (step 940).

Thereafter, the user terminal receives a handover response message (MOB_BSHO-RSP) as a response message (step 950). If there is no change in the target, the user terminal performs a handover to the target and terminates the algorithm according to the present invention.

10 is a flowchart illustrating a handover procedure of a serving base station in a base station request handover using a downlink channel state message (DCD) from an IEEE 802.16e communication system to a heterogeneous communication system according to an embodiment of the present invention.

Referring to FIG. 10, the base station transmits a DL-MAP message, a downlink channel state message (DCD), and an uplink channel state message (UCD) including information on the base station and handover information on a heterogeneous network. Transmit (step 1010).

Thereafter, when the user terminal needs to handover by receiving a signal size and a channel state from the user terminal, the handover is determined (step 1020), and a list of handoverable heterogeneous network base stations or access points is prepared.

Thereafter, a handover notification request message (HO_notification_request) requesting information required for handover to a heterogeneous network base station or an access point included in the list is transmitted to the core network (step 1030).

Thereafter, a handover notification response message (HO_notification_response) including information on a base station or an access point that is determined as a handover target, that is, a target, is received from the core network (step 1040).

Thereafter, the base station includes the information on the determined target in a base station handover request message (MOB_BSHO-REQ) and transmits the information to the user terminal (step 1050), indicating that the user handovers from the user terminal to the target. Receive an over message (MOB_HO-IND) (step 1060).

Thereafter, a handover response message MOB_BSHO-RSP, which is a response message to the handover message MOB_HO-IND, is transmitted to the user terminal (step 1070).

Thereafter, the base station transmits a handover notification message (Vertical_HO_indication) that the user terminal performs the handover to the core network (step 1080) and terminates the algorithm according to the present invention.

FIG. 11 is a block diagram of a user terminal, an IEEE 802.16e communication system base station, a core network, and a target base station or access point according to an embodiment of the present invention.

First, the user terminal will be described with reference to FIG. 11. The interface module 1110 is a module for communicating with other nodes and includes a radio frequency (RF) processor and a baseband processor. The RF processor converts a signal received through an antenna into a baseband signal and provides the baseband signal to the baseband processor, and converts the baseband signal from the baseband processor into an RF signal so as to be transmitted on an actual air. Transmit via antenna In particular, according to the present invention, the interface module may include an interface module 1110 for each of a plurality of mobile communication systems in addition to the interface module 1110 supporting the IEEE 802.16e communication system.

The controller 1120 controls the overall operation of the user terminal. For example, a handover related message and a downlink channel status message (DCD) received through the interface module 1110 in accordance with the present invention may be performed in addition to the normal functions, performing processing and control for voice call and data communication. The handover related message provided to the handover manager 1140 and provided by the handover manager 1140 is transmitted through the interface module 1110.

The handover management unit 1140 determines heterogeneous networks that can be supported by the core network through the DCD message according to the instruction and provision information of the control unit 1120, and determines whether to perform handover by measuring received signals and performing a handover process. Do this.

Alternatively, the handover process is performed by the handover related message transmitted by the base station. The handover manager 1140 may report the received signal size to the IEEE 802.16e base station. The handover process is performed by exchanging a handover related message with the base station and taking an action according to the message.

The storage unit 1130 stores a program for controlling the overall operation of the apparatus and temporary data generated during program execution.

In the above block configuration, the controller 1120 may perform a function of the handover manager 1140. In the present invention, it is shown to configure them separately to explain each function separately. Accordingly, when the product is actually implemented, all of the functions of the handover management unit 1140 may be configured to be processed by the controller 1120, and only some of the functions may be configured to be processed by the controller 1120.

now. Referring to FIG. 6, the IEEE 802.16e communication system base station is described. The interface module 1110 includes a wireless communication module for communicating with the user terminal and a wired communication module for communicating with another wired node. .

The controller 1120 controls the overall operation of the IEEE 802.16e communication system base station. For example, it performs processing and control for voice call and data communication, and provides a handover related message received through the interface module 1110 to the handover management unit 1140 in addition to the usual functions. And a downlink channel state message (DCD) including a handover related message provided by the handover management unit 1140 and information of a heterogeneous network, through the interface module 1110.

The handover manager 1140 generates a downlink channel state message (DCD) including neighbor network information according to the instruction and provision information of the controller 1120, and checks the measured signal strength from the mobile communication terminal. To determine whether to perform the handover to perform the handover process. The handover process is performed by the handover request received from the mobile communication terminal. The handover process is performed by exchanging a handover related message with the base station and taking an action according to the message.

The storage unit 1130 stores a program for controlling the overall operation of the apparatus and temporary data generated during program execution.

In the above block configuration, the controller 1120 may perform a function of the handover manager 1140. In the present invention, it is shown to configure them separately to explain each function separately. Accordingly, when the product is actually implemented, all of the functions of the handover management unit 1140 may be configured to be processed by the controller 1120, and only some of the functions may be configured to be processed by the controller 1120.

now. Referring to FIG. 6, the core network will be described. The interface module 1110 is a module for communicating with another node and includes a wired communication interface for communicating with another node.

The controller 1120 controls the overall operation of the core network. For example, it performs processing and control for voice call and data communication, and provides a handover related message received through the interface module 1110 to the handover management unit 1140 in addition to the usual functions. The handover related message provided by the handover manager 1140 is transmitted through the interface module 1110.

When the handover management unit 1140 receives the handover related message according to the instruction and provision information of the control unit 1120, the handover management unit 1140 transmits the handover related message to the corresponding node and, if necessary, the user terminal in the received handover related message. The target to be over determined is determined and the target is included in the received handover message and transmitted to the corresponding node.

The storage unit 1130 stores a program for controlling the overall operation of the apparatus and temporary data generated during program execution.

In the above block configuration, the controller 1120 may perform a function of the handover manager 1140. In the present invention, it is shown to configure them separately to explain each function separately. Accordingly, when the product is actually implemented, all of the functions of the handover management unit 1140 may be configured to be processed by the controller 1120, and only some of the functions may be configured to be processed by the controller 1120.

Finally. Referring to FIG. 6, the target base station or the access point will be described. The interface module 1110 is a module for communicating with another node, and includes a wired and wireless communication module for communicating with another node.

The controller 1120 controls the overall operation of the target base station or access point. For example, it performs processing and control for voice call and data communication, and provides a handover related message received through the interface module 1110 to the handover management unit 1140 in addition to the usual functions. The handover related message provided by the handover manager 1140 is transmitted through the interface module 1110.

When the handover management unit 1140 receives a handover related message from the core network according to the instruction and provision information of the control unit 1120, the handover management unit 1140 generates and transmits a response message including a signal state according to the message, or the user The terminal is provided with information to handover.

The storage unit 1130 stores a program for controlling the overall operation of the apparatus and temporary data generated during program execution.

In the above block configuration, the controller 1120 may perform a function of the handover manager 1140. In the present invention, it is shown to configure them separately to explain each function separately. Accordingly, when the product is actually implemented, all of the functions of the handover management unit 1140 may be configured to be processed by the controller 1120, and only some of the functions may be configured to be processed by the controller 1120. .

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the scope of the following claims, but also by the equivalents of the claims.

The present invention enables a user terminal having multiple interfaces to perform handover from an IEEE 802.16e communication system to a heterogeneous communication system. As a result, the wireless communication service can be continuously provided without interruption, thereby improving the quality of the wireless communication service.

Claims (54)

A method for handover of a UE request from a broadband wireless access communication system to a heterogeneous communication system, Receiving, by the user terminal, a message including a heterogeneous communication system handover type supported by a core network from a base station and measuring a signal size; If the measurement result indicates a need for handover to a heterogeneous communication system, transmitting, by the user terminal, a terminal handover request message including a list of heterogeneous communication systems capable of handover to the base station; Receiving, from the base station, a handover response message including information on a target that can be actually handed over by the user terminal; Transmitting a handover message including information on the target. The method of claim 1, And the message including the type of heterogeneous communication system handover supported by the core network is a downlink channel status message. The method of claim 1, The list of heterogeneous communication systems that can be handed over by the user terminal included in the terminal handover request message includes information indicating the number of heterogeneous communication systems that can be handed over by the user terminal, and the number of heterogeneous communication systems equal to the number. Information and a signal magnitude state for each of said heterogeneous communication systems. The method of claim 1, Information on a target that can be actually handed over by the user terminal included in the handover response message includes information indicating that the base station performs handover to a heterogeneous communication system and a type of heterogeneous communication system handover that the user terminal can actually perform. And information on a target according to the handover type. The method of claim 1, And the information on the target included in the handover message is information indicating that the user terminal performs a handover between heterogeneous communication systems, and information on a target to which the user terminal intends to handover. A method for handover of a terminal request from a base station to a heterogeneous communication system in a broadband wireless access communication system, Transmitting a message including a heterogeneous communication system handover type supported by a core network to a user terminal; Receiving, by the user terminal, a terminal handover request message including a list of heterogeneous communication systems capable of handover; Transmitting, to the core network, a handover notification request message included in the heterogeneous communication system list and directed to a target capable of handover to the core network, and receiving a handover notification response message in response; Transmitting information about a target included in the handover notification response message to the user terminal by including the information in the handover response message; Receiving a handover message including information on the target; After receiving the handover message, transmitting a handover notification message to the core network. The method of claim 6, And the message including the type of heterogeneous communication system handover supported by the core network is a downlink channel status message. The method of claim 6, The list of heterogeneous communication systems that can be handed over by the user terminal included in the terminal handover request message includes information indicating the number of heterogeneous communication systems that can be handed over by the user terminal, and the number of heterogeneous communication systems equal to the number. Information and a signal magnitude state for each of said heterogeneous communication systems. The method of claim 6, The information on the target included in the handover response message includes information indicating that the base station performs handover to a heterogeneous communication system, types of heterogeneous communication system handovers that the user terminal can actually perform, and types of the handover. And information on the target according to the method. The method of claim 6, The information on the target included in the handover message is information indicating that the user terminal device performs a handover between heterogeneous communication systems, and the method of the user terminal characterized in that the information of the target to handover. In a handover method of a core network from a broadband wireless access communication system to a heterogeneous communication system, Receiving a handover notification request message from the base station to the targets capable of handover by the core network and the user terminal and transmitting the handover notification request messages to the targets, respectively; After the transmission, receiving a handover notification response message including each signal state in response to determining a target; Transmitting a handover notification response message including the determined target information to the base station; And receiving a handover notification message indicating a handover to the user terminal from the base station and transmitting the handover notification message to the target. In a handover method of a target from a broadband wireless access communication system to a heterogeneous communication system, Receiving a handover notification request message from a core network; And transmitting a signal state of the target to the core network in a handover notification response message which is a response message of the handover notification request message. A base station request handover method of a user terminal from a broadband wireless access communication system to a heterogeneous communication system, Receiving, by the user terminal, a message including a heterogeneous communication system handover type supported by a core network from a base station, measuring a signal size, and transmitting the signal to the base station; Receiving, from the base station, a base station handover request message including information on a target that can be actually handed over by the user terminal; Transmitting a handover message including information on the target to the base station; Receiving a handover response message including information on the target from the base station. The method of claim 13, And the message including the type of heterogeneous communication system handover supported by the core network is a downlink channel status message. The method of claim 13, Information on a target that the user terminal can actually hand over in the base station handover request message includes information indicating that the base station performs handover to a heterogeneous communication system, and information on a heterogeneous communication system handover that the user terminal can actually perform. And information on a target according to the handover type. The method of claim 13, And the information on the target included in the handover message is information indicating that the user terminal performs a handover between heterogeneous communication systems, and information on a target to which the user terminal intends to handover. The method of claim 13, Information on a target that can be actually handed over by the user terminal included in the handover response message includes information indicating that the base station performs handover to a heterogeneous communication system and a type of heterogeneous communication system handover that the user terminal can actually perform. And information on a target according to the handover type. A base station request handover method of a base station from a broadband wireless access communication system to a heterogeneous communication system, Transmitting, by the base station, a message including a type of heterogeneous communication system handover supported by a core network to a user terminal, and receiving a signal size and a channel state measured from the user terminal; When the size measurement result indicates a need for handover to a heterogeneous communication system, determining to perform handover to the heterogeneous communication system; After the handover decision is made, the user terminal transmitting a handover notification request message directed to targets that can actually be handed over to the core network and receiving a handover notification response message in response; Transmitting information about a target included in the handover notification response message to the user terminal by including the information on the target in the base station handover request message; Receiving a handover message including information on the target from the user terminal; After receiving the handover message, transmitting a handover response message for the handover message to the user terminal; After receiving the handover message, transmitting a handover notification message directed to the target to the core network. The method of claim 18, And the message including the type of heterogeneous communication system handover supported by the core network is a downlink channel status message. The method of claim 18, The information on the target included in the base station handover request message includes information indicating that the base station performs handover to a heterogeneous communication system, types of heterogeneous communication system handovers that the user terminal can actually perform, and types of the handover. And information on the target according to the method. The method of claim 18, And the information on the target included in the handover message is information indicating that the user terminal performs a handover between heterogeneous communication systems, and information on a target to which the user terminal intends to handover. The method of claim 18, The information on the target included in the handover response message includes information indicating that the base station performs handover to a heterogeneous communication system, types of heterogeneous communication system handovers that the user terminal can actually perform, and types of the handover. And information on the target according to the method. An apparatus of a user terminal supporting terminal request handover from a broadband wireless access communication system to a heterogeneous communication system, A communication module for communicating with another node, A heterogeneous communication system capable of handover when receiving a message including a heterogeneous communication system handover type supported by a core network from the base station through the communication module and measuring a signal size to indicate the need for handover to the heterogeneous communication system Transmitting a terminal handover request message including a list to the base station, receiving a handover response message including information on a target to which the user terminal can actually handover from the base station, and including information on the target; A handover management unit for transmitting a handover message; Device for storing the program and data required for the handover management unit during operation. The method of claim 23, wherein And the message including the type of heterogeneous communication system handover supported by the core network is a downlink channel status message. The method of claim 23, wherein The list of heterogeneous communication systems that can be handed over by the user terminal included in the terminal handover request message includes information indicating the number of heterogeneous communication systems that can be handed over by the user terminal, and the number of heterogeneous communication systems equal to the number. Information and signal magnitude status for each of the heterogeneous communication systems. The method of claim 23, wherein Information on a target that can be actually handed over by the user terminal included in the handover response message includes information indicating that the base station performs handover to a heterogeneous communication system and a type of heterogeneous communication system handover that the user terminal can actually perform. And information on a target according to the handover type. The method of claim 23, wherein And the information on the target included in the handover message is information indicating that the user terminal performs handover between heterogeneous communication systems, and information on a target to which the user terminal intends to handover. An apparatus of a base station supporting terminal request handover from a broadband wireless access communication system to a heterogeneous communication system, A communication module for communicating with another node, Transmitting a message including a heterogeneous communication system handover type supported by a core network to the user terminal through the communication module, receiving a terminal handover request message including a list of heterogeneous communication systems capable of handover by the user terminal, Sending a handover notification request message included in the heterogeneous communication system list and directed to targets capable of handover support to the core network and receiving a handover notification response message in response to handover information on the included target. A handover management unit including the response message to the user terminal, receiving a handover message including information on the target, and transmitting a handover notification message to the core network; Device for storing the program and data required for the handover management unit during operation. The method of claim 28, And the message including the type of heterogeneous communication system handover supported by the core network is a downlink channel status message. The method of claim 28, The list of heterogeneous communication systems that can be handed over by the user terminal included in the terminal handover request message includes information indicating the number of heterogeneous communication systems that can be handed over by the user terminal, and the number of heterogeneous communication systems equal to the number. Information and signal magnitude status for each of the heterogeneous communication systems. The method of claim 28, The information on the target included in the handover response message includes information indicating that the base station performs handover to a heterogeneous communication system, types of heterogeneous communication system handovers that the user terminal can actually perform, and types of the handover. An apparatus comprising the information of the targets according. The method of claim 28, And the information on the target included in the handover message is information indicating that the user terminal performs handover between heterogeneous communication systems, and information on a target to which the user terminal intends to handover. In a device of a core network supporting handover from a broadband wireless access communication system to a heterogeneous communication system, A communication module for communicating with another node, A handover notification response message which receives a handover notification request message from the base station to targets capable of handover from the base station through the communication module and transmits the handover notification request message to the targets, respectively, and includes the respective signal states in response. Receive a target to determine the target to send a handover notification response message including the information of the determined target to the base station, and receives a handover notification message indicating the handover to the user terminal from the base station to transmit to the target With handover management department to say, Device for storing the program and data required for the handover management unit during operation. In the apparatus of the target that supports handover from a broadband wireless access communication system to a heterogeneous communication system, A communication module for communicating with another node, A handover management unit receiving a handover notification request message from a core network through the communication module and transmitting a handover notification response message including a signal state of the target to the core network; Device for storing the program and data required for the handover management unit during operation. An apparatus of a user terminal supporting a base station request handover from a broadband wireless access communication system to a heterogeneous communication system, A communication module for communicating with another node, Receives a message including a heterogeneous communication system handover type supported by a core network from the base station through the communication module, measures a signal size, and transmits the signal to the base station, and from the base station to a target to which the user terminal can actually handover. A handover management unit for receiving a base station handover request message including information, transmitting a handover message including information about the target to the base station, and receiving a handover response message including information about the target from the base station. Wow, Device for storing the program and data required for the handover management unit during operation. The method of claim 35, wherein And the message including the type of heterogeneous communication system handover supported by the core network is a downlink channel status message. The method of claim 35, wherein Information on a target that can be actually handed over by the user terminal included in the base station handover request message includes information indicating that the base station performs handover to a heterogeneous communication system, and a heterogeneous communication system handover that the user terminal can actually perform. And information on a target according to the handover type. The method of claim 35, wherein Information on a target that can be actually handed over by the user terminal included in the handover response message includes information indicating that the base station performs handover to a heterogeneous communication system and a type of heterogeneous communication system handover that the user terminal can actually perform. And information on a target according to the handover type. The method of claim 35, wherein And the information on the target included in the handover message is information indicating that the user terminal performs a handover between heterogeneous communication systems, and information on a target to which the user terminal intends to handover. An apparatus of a base station supporting base station request handover from a broadband wireless access communication system to a heterogeneous communication system, A communication module for communicating with another node, Through the communication module, a message including a heterogeneous communication system handover type supported by the core network is transmitted to the user terminal, and the signal size and channel state measured from the user terminal are received, and the size measurement result is handed to the heterogeneous communication system. In case of indicating the need for over, it is determined to perform handover to a heterogeneous communication system so that the user terminal sends a handover notification request message to the core network to the target network which can actually be handed over and receives a handover notification response message in response. Including the information on the target included in the handover notification response message in the base station handover request message to transmit to the user terminal and receives a handover message including the information about the target from the user terminal, the handover message On A handover management unit which transmits a handover response message to the user terminal and transmits a handover notification message directed to the target to the core network; Device for storing the program and data required for the handover management unit during operation. The method of claim 40, And the message including the type of heterogeneous communication system handover supported by the core network is a downlink channel status message. The method of claim 40, Information on a target that the user terminal can actually hand over in the base station handover request message includes information indicating that the base station performs handover to a heterogeneous communication system, and information on a heterogeneous communication system handover that the user terminal can actually perform. And information on a target according to the handover type. The method of claim 40, The information on the target included in the handover response message includes information indicating that the base station performs handover to a heterogeneous communication system, types of heterogeneous communication system handovers that the user terminal can actually perform, and types of the handover. An apparatus comprising the information of the targets according. The method of claim 40, And the information on the target included in the handover message is information indicating that the user terminal performs handover between heterogeneous communication systems, and information on a target to which the user terminal intends to handover. A communication system supporting terminal request handover from a broadband wireless access communication system to a heterogeneous communication system, A terminal handover including a list of heterogeneous communication systems capable of handover when receiving a message including a heterogeneous communication system handover type supported by a core network, and measuring a signal size to indicate the need for handover to the heterogeneous communication system. A user terminal for transmitting a request message, for receiving a handover response message including information on a target that the user terminal can actually handover to, and for transmitting a handover message including information on the target; Transmitting a message including a type of heterogeneous communication system handover supported by the core network to the user terminal, receiving a terminal handover request message including a list of heterogeneous communication systems capable of handover by the user terminal, and receiving the heterogeneous communication system Sending a handover notification request message included in the list and directed to targets capable of handover support to the core network and receiving a handover notification response message in response, the information on the included target is included in the handover response message. A base station for transmitting the handover message to the core network, receiving a handover message including information on the target, and transmitting the handover notification message to the core network; Receives a handover notification request message sent from the base station to targets capable of handover by the core network and the user terminal, respectively, to the targets and receives a handover notification response message including respective signal states in response. A core network that determines a target and transmits a handover notification response message including the determined target information to the base station, receives a handover notification message indicating a handover to the user terminal from the base station, and transmits the handover notification message to the target; , And a target for receiving a handover notification request message from the core network and sending a handover notification response message including the signal status of the target to the core network. The method of claim 45, And the message including the type of heterogeneous communication system handover supported by the core network is a downlink channel status message. The method of claim 45, The list of heterogeneous communication systems capable of handing over by the user terminal included in the terminal handover request message includes information indicating the number of heterogeneous communication systems capable of handover by the user terminal and the number of heterogeneous communication systems equal to the number. Information and signal magnitude status for each of the heterogeneous communication systems. The method of claim 45, The information on the target included in the handover response message includes information indicating that the base station performs handover to a heterogeneous communication system, types of heterogeneous communication system handovers that the user terminal can actually perform, and types of the handover. A system comprising targets according to the information. The method of claim 45, And the information on the target included in the handover message is information indicating that the user terminal performs a handover between heterogeneous communication systems, and information on a target to which the user terminal intends to handover. A communication system supporting base station request handover from a broadband wireless access communication system to a heterogeneous communication system, When a message including the heterogeneous communication system handover type supported by the core network is transmitted to the user terminal, the measured signal size and channel state are received from the user terminal, and the size measurement result indicates the need for handover to the heterogeneous communication system. Determines to perform a handover to a heterogeneous communication system so that the user terminal actually transmits a handover notification request message directed to targets capable of handover to a core network, receives a handover notification response message in response, and receives the handover notification response message. The base station handover request message includes information on the target included in the base station handover request message and transmits to the user terminal, and receives a handover response message including information on the target from the user terminal and handover notification message directed to the target And a base station for transmission to the core network, Receives a handover notification request message sent from the base station to targets capable of handover by the core network and the user terminal, respectively, to the targets and receives a handover notification response message including respective signal states in response. A core network that determines a target and transmits a handover notification response message including the determined target information to the base station, receives a handover notification message indicating a handover to the user terminal from the base station, and transmits the handover notification message to the target; , A target for receiving a handover notification request message from the core network and transmitting a handover notification response message including a signal state of the target to the core network; Receiving a message including the type of heterogeneous communication system handover supported by the core network from the base station and measuring the signal size and transmitting the signal to the base station, and includes information on the target that the user terminal can actually handover from the base station And a user terminal receiving a base station handover request message, transmitting a handover message including information about the target to the base station, and receiving a handover response message including information about the target from the base station. System. 51. The method of claim 50, And the message including the type of heterogeneous communication system handover supported by the core network is a downlink channel status message. 51. The method of claim 50, Information on a target that the user terminal can actually hand over in the base station handover request message includes information indicating that the base station performs handover to a heterogeneous communication system, and information on a heterogeneous communication system handover that the user terminal can actually perform. And information on a target according to the handover type. 51. The method of claim 50, The information on the target included in the handover response message includes information indicating that the base station performs handover to a heterogeneous communication system, types of heterogeneous communication system handovers that the user terminal can actually perform, and types of the handover. A system comprising targets according to the information. 51. The method of claim 50, And the information on the target included in the handover message is information indicating that the user terminal performs a handover between heterogeneous communication systems, and information on a target to which the user terminal intends to handover.

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