KR101075668B1 - The Method for Handoff of Different Type Network Supported Quality of Service - Google Patents

Abstract

The present invention is a method for improving the handoff process required when the terminal moves between heterogeneous networks. Due to different characteristics between heterogeneous networks, problems such as deterioration of service quality, increased delay time, or network disconnection may occur in the handoff process, and the present invention can solve problems such as the terminal itself may use before handoff. This method is to grasp QoS information in advance and perform handoff based on this. That is, before performing the handoff, the terminal determines whether QoS of the handoff target base stations around the terminal is supported through the interworking wireless network which already has an active connection with the interworking network core network, and performs the actual handoff process based on this. . Since the UE can grasp the state of the target base stations before performing the handoff, it is possible to determine the target base station based on the QoS support information and the received signal strength as well as the existing received signal strength.

Different Type Network, Handoff, QoS

Description

Handoff method between heterogeneous networks considering service quality support {The Method for Handoff of Different Type Network Supported Quality of Service}             

1 is a view showing an interworking network structure according to the present invention.

2 is a diagram illustrating a handoff target cell selection procedure between different networks supporting QoS according to the present invention.

3 is a view showing the operation of the terminal according to the present invention.

4 is a view showing the operation of the network connection relay node located in the interlocking network core network according to the present invention.

FIG. 5 illustrates a process of selecting a handoff target cell between different networks supporting QoS according to another embodiment of the present invention.

6 is a view showing the operation of the terminal according to another embodiment of the present invention.

7 is a view showing the operation of the network connection relay node located in the interlocking network core network according to another embodiment of the present invention.

8 is a diagram illustrating a procedure in the case of successful vertical handoff according to another embodiment of the present invention.

9 is a diagram illustrating a procedure when a vertical handoff fails according to another embodiment of the present invention.

The present invention relates to a handoff method that can improve QoS degradation caused when a terminal performs handoff between two radio access networks in an interworking network structure composed of different kinds of networks.

In the case of handoff between heterogeneous networks, in order to select a cell available in the target network, the UE receives a signal of the target network, determines a cell having the strongest signal strength as a handoff target cell, and performs handoff. That is, in order for the terminal to perform handoff between heterogeneous networks, it is necessary to determine handoff performance. This determination may be determined by the terminal's own judgment according to the preferred network setting of the terminal, or may be determined by the user's artificial decision. However, the decision of the handoff row is often at the discretion of the user. This is because different network usage cost problems that arise in the case of handoff between heterogeneous networks cannot be ignored.

When the user determines to perform the handoff, the terminal receives the cell signal of the target network and finds the cell in which the strongest signal is received. When the terminal finds a cell in which the strongest signal is received, the terminal determines that the cell is a handoff target cell, and the terminal attempts to connect to the network through the handoff target cell. At this time, in addition to the wireless connection for the connection between the terminal and the network, an additional connection setting procedure such as performing an authentication procedure for the terminal or a mobile IP protocol for supporting IP mobility is performed if necessary according to service characteristics. Subsequently, when the packet is received through the new wireless path by completing the connection setup to the new network, the terminal terminates the connection through the existing network to complete the handoff procedure.

When a terminal moves between heterogeneous networks, a problem may occur because data rates and service characteristics provided by respective radio access networks are different. In particular, when the data rate supported by each network is large, such as interworking between a wireless local area network (WLAN) and a universal mobile telecommunication system (UMTS) network, supporting the service used by the terminal continuously after handoff. This requires a proper QoS control method and a handoff to the target cell that can satisfy the desired QoS during handoff. However, in the related art, the terminal receives only cell ID information of a handoff target network, and selects a handoff target cell based only on the strength of a received signal based on the received cell ID information. Accordingly, the terminal may not know whether there is a cell capable of supporting a desired QoS until the terminal accesses the target network during handoff between different radio access networks, and which cell is the cell.

As such, in case of handoff between heterogeneous networks, if a terminal does not support a satisfactory QoS, problems such as service quality deterioration, service delay, and service disconnection may occur. In addition, the UE has a problem in that it finds a cell that can satisfy the desired QoS and performs another handoff.

Accordingly, an object of the present invention, which was devised to solve the problems of the prior art operating as described above, is to provide a method of notifying a cell in advance of supporting a desired QoS in a handoff between heterogeneous networks.

In addition, another object of the present invention is to provide a stable service by pre-selecting a cell capable of supporting a desired QoS in the terminal when handoff between heterogeneous networks.

An embodiment of the present invention, which was created to achieve the above object, relates to a method in which a terminal connected to an interworking network core network through an interworking wireless network performs a handoff to a heterogeneous network supporting QoS desired by the terminal. In

Collecting information of base stations that can be received by a terminal from a neighboring network and receiving strength of a base station signal;

Generating a target probe request message including information on the collected base stations and QoS information desired by the terminal and transmitting the generated target probe request message to the interworking wireless network;

Checking whether a target probe response message corresponding to the target probe request message is received;

Receiving the target probe response message, checking whether the target probe response message includes base station information on at least one target base station capable of supporting a desired QoS of the terminal;

If the check result is the base station information that can support the desired QoS, characterized in that it comprises the step of determining the target base station by the base station information, and the handoff to the determined target base station.

According to another embodiment of the present invention, a handoff between heterogeneous networks supporting a QoS desired by a terminal is performed through a linked wireless network connected to a terminal and a network connection relay node connected to a wireless network control / management node of the linked wireless network. In the way,

Receiving, from the radio network control / management node, a relay vertical handoff request message including QoS information requested by a terminal and base station information of base stations that the terminal can receive;

Transmitting a forward vertical handoff request message including the base station information and the QoS required by the terminal to the base stations corresponding to the base station information;

Receiving, by the base station, a adaptive handoff response message including information on whether the terminal can support QoS required by the terminal;

Selecting a base station that can best support the QoS required by the terminal according to the received vertical handoff response messages, and transmitting a vertical handoff direct message including base station information of the selected base station to the terminal; Characterized in that it comprises a.

The operation principle of the preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. Like reference numerals are used to designate like elements even though they are shown in different drawings, and detailed descriptions of related well-known functions or configurations are not required to describe the present invention. If it is determined that it can be blurred, the detailed description thereof will be omitted. The following terms are defined in consideration of the functions of the present invention, and may be changed according to the intentions or customs of the user, the operator, and the like. Therefore, the definition should be based on the contents throughout this specification.

1 is a diagram illustrating an interworking network structure according to the present invention.

Referring to FIG. 1, the terminal 101 is connected to an interworking network core network 109 through an interworking radio network 1 106, an interworking radio network 2 107, or an interworking radio network 3 108. The interworking network core network 109 receives the network 101 even though the terminal 101 is connected through various interworking wireless networks 1 to 3 (106 to 108), and connects the network connection relay node 102 to the external network 116. It supports to communicate with external network through. In this case, when the terminal 101 moves between the interworking wireless network 1 106, the interworking wireless network 2 107, and the interworking wireless network 3 108, the terminal 101 is connected to the interworking network core network (regardless of the movement). 109) should be able to support continuous services. Therefore, for continuous service support in the interworking network core network 109, the network connection relay node 102 is handed over the interfaces 113, 114, 115 with the various interworking wireless networks 106-108. It is responsible for mediating service connection using off-the-shelf mobility support. In each of the interworking wireless networks 106 to 108, there are radio network control / management nodes 1 to 3 (103, 104, 105) that are in charge of interworking with the radio resources of the corresponding interworking wireless network and access control and interworking network core network 109. do. The terminal 101 can communicate with the interlocking network core network 109 through one interlocking wireless network at a moment, and the network connection relay node 102 can establish a connection for the control function with the terminal 101. .

In the present invention, the terminal checks and prepares the desired QoS requirements before handoff so that the terminal can continuously support the service even after the handoff.

First, according to the present invention, when handoff is performed on another type of network, messages are transmitted / received on the terminal and the network in order to enable the terminal to grasp information of the handoff target network.

The target probe request message includes a terminal ID, a message ID, a sequence of base station information, and a QoS requirement of the terminal. The target probe request message is a message transmitted to a core network of an interworking network in order to grasp information of a target network when a terminal tries to perform handoff between heterogeneous networks. The target probe request message includes information of base stations of a target network that can be received by the terminal, and collects state information of each base station to inform the terminal of base stations included in the message in the interlocked network core network. .                     

Accordingly, the base station information included in the target probe request message includes a target interworking radio network ID, a base station ID in the target interworking wireless network, and a base station signal strength received by the terminal. Since the terminal may receive a plurality of base stations, the plurality of base station information may be included in the target probe request message. In addition, the relay target probe request message (Relay Target Probe Request) or the forward target probe request message (forward Target Probe Request) is also different from the target probe request message and its contents and configuration. However, the relay target probe request messages may include additional information according to the connection between the interworking radio network and the interworking network core network, and the base station information may selectively remove information irrelevant to the interworking radio network. do.

The target probe response message includes serviceable QoS information that can be supported for each base station by checking the base station information requested by the terminal in response to the target probe request message requested by the terminal. That is, the target interworking radio network ID, the base station ID in the corresponding interworking wireless network, and a plurality of QoS information that can be supported by the base station are included. When the terminal receives the target probe response message, the terminal can identify a base station that can satisfy the desired QoS. When the terminal performs handoff between heterogeneous networks, the terminal can determine the target network and the base station to which the connection is attempted. .

2 is a diagram illustrating a handoff target cell selection procedure between different networks supporting QoS according to the present invention.                     

Referring to FIG. 2, the terminal 201 operates a wireless interface that can be used by the terminal 201 to grasp information of a neighboring handoff target network. Here, the terminal 201 intends to perform handoff between heterogeneous networks while being connected to the interworking network core network 209 through the interworking wireless network 1 206.

 The terminal 201 acquires base station information sent by the base stations of the companion radio network 2 207 and the companion radio network 3 208 through the radio channels 211 and 212. In this case, the information that can be obtained by the terminal 201 is a simple base station ID broadcasted by the corresponding base station and a received signal strength.

The received terminal 201, which collects base station information of neighboring wireless networks, includes a target probe request message 223, which is an information request message for handoff between heterogeneous networks, by putting the desired QoS information on the base station information. ) Is transmitted to the interworking radio network 1 (206).

The interworking radio network 1 206 that receives the target probe request message 223 relays the target probe request message 223 to the relay target probe request through the radio network control / managed node 1 203. It is carried in message 224 to the network connection relay node 202.

The network connection relay node 202 receiving the relay target probe request message 224 may control a wireless network control / management node of an interworking wireless network managing the base station according to the base station information of the relay target probe request message 224. The forward target probe request message 225 is delivered to the 2,3 (204, 205). The forward target probe request message 225 is composed of a message including base station information and QoS information of the terminal by extracting only base station information related to the corresponding interworking wireless network from the relay target probe request message 224.

The radio network control / management nodes 2, 3 (204, 205) of each of the interworking radio networks 2, 3 (206, 207) that receive the forward target probe request message (225) are included in the forward target probe request message (225). The resource and load conditions of the base stations corresponding to the included base station information are checked to determine whether the QoS request information of the terminal included in the forward target probe request message 225 can be satisfied. Through this, the wireless network control / management nodes 2, 3 (204, 205) relay the network connection by putting the QoS information that can be supported by the base station in the base station in the reply target probe response message 226. Forward to node 202. In this case, the reply target probe response message 226 includes QoS information that can be supported to the terminal together with the corresponding base station information. Through this, the radio network control / management nodes 2, 3 (204, 205) may perform a preparation process such as radio resource allocation to accommodate the terminal when the terminal performs a handoff.

The network connection relay node 202 transmits a forward target probe response message 227 incorporating the reply target probe response messages 226 from each of the interworking wireless networks 2, 3 (207, 208). 203). The forward target probe response message 227 includes QoS information of each base station that the terminal 201 can support to the terminal 201 when the terminal 201 intends to perform a handoff between heterogeneous networks.

When the wireless network control / management node 1 203 receives the forward target probe response message 227, it transmits a target probe response message 228 to the terminal 201 through the existing wireless connection 210. Then, the terminal 201 determines a handoff target base station to select when performing handoff between heterogeneous networks based on supportable QoS information of each base station included in the target probe response message 228, and the determined Perform a handoff to the base station.

Hereinafter, the operation of the terminal according to the present invention will be described with reference to FIG. 3.

Referring to FIG. 3, in step 301, the terminal starts handoff between heterogeneous networks, and in step 302, the terminal collects base station information around the terminal using a network interface that can be used by the terminal. In this case, the terminal collects base station ID information that can be received by each network and reception strength of the corresponding base station signal. In step 303, the terminal generates and transmits a target probe request message with the collected information and the QoS request information desired by the terminal, and activates a probe timer. In step 304, the terminal checks whether a target probe response message has been received. As a result of the check, if the target probe response message is not received, the terminal checks whether the operation of the target probe timer is terminated in step 305. If the probe timer expires as a result of the check, a handoff target according to the received signal strength is determined in step 308. If the probe timer has not expired, the process returns to step 304.                     

If the target probe response message is received as a result of the checking, the target probe result is determined in step 306. The determining of the target probe result may include determining whether there is a base station capable of supporting QoS desired by the terminal among neighboring base stations capable of receiving a signal in the target probe response message received by the terminal. If there is no QoS information that each base station can support in this step (failure), the flow proceeds to step 308 to determine the handoff target according to the received signal strength. Here, the process of determining the handoff target according to the received signal strength is a process of selecting the handoff target base station as in the conventional handoff procedure. When the handoff target base station is selected, the process proceeds to step 309.

If there is a base station capable of supporting the desired QoS as a result of the target probe, the terminal proceeds to step 307 to determine a handoff target according to the target probe result. That is, the terminal selects a base station that best matches a desired QoS request according to the QoS information for each base station in the target probe response message received by the terminal as a handoff target. When the handoff target base station is selected, the handoff between heterogeneous networks is performed in step 309.

In step 309, the handoff process between heterogeneous networks is performed by performing a series of steps for handoff to the base station and the interworking wireless network selected in step 307 or 308. Here, specific procedures of the handoff process between heterogeneous networks are appropriately performed according to the interworking wireless network. When the substantial handoff procedure is performed, handoff termination between heterogeneous networks is performed in step 310, thereby completing the handoff procedure.

Hereinafter, the operation of the network connection relay node located in the interlocking network core network according to the present invention will be described with reference to FIG. 4.

Referring to FIG. 4, in operation 401, a relay target probe request message is received from a wireless network control / management node of an interworking wireless network to which a terminal is connected, for handoff between heterogeneous networks in a network connection relay node. When the network connection relay node receives the relay target probe request message, it transmits a forward target probe request message to the corresponding interworking wireless network in step 402, operates a probe timer, and then proceeds to step 403. Here, the forward target probe request message is a message for delivering the target probe request message to the radio network control / management node of the interlocking radio network corresponding to the target interworking radio network ID of the relay probe request message transmitted by the terminal. At this time, the timer is operated with a response waiting time of the forward target probe request message transmitted to each wireless network control / management node.

In step 403, the network connection relay node checks whether a reply target probe response message has been received. If there is no reply target probe response message transmitted from each radio network control / management node as a result of the check, the timer check is performed in step 404. The timer check in step 404 checks whether a timer value, which is a waiting time of the target probe response message, has expired. If the timer expires, the timer check proceeds to step 407. When the timer is in operation, the timer check returns to step 403.

If there is a reply target probe response message received as a result of the check, in step 405, the network connection relay node stores the supportable QoS information included in the reply target probe response message, and subsequently transmits a forward target probe response message. Make it available, and proceed to step 406.

In step 406, the network connection relay node checks whether as many reply target probe response messages as the UE has transmitted to the corresponding interworking wireless network in step 402. If the number of response messages received is smaller than the number of transmitted messages as a result of the checking process, the reply target probe response message to be received still remains, and the flow returns to step 403. When receiving the number of response messages transmitted as a result of the check, in step 407, a forward target probe response message is transmitted based on the received response messages.

In step 407, the network connection relay node uses the forward target probe response message created by integrating supportable QoS information for each base station stored in the target probe response result, to a wireless network control / management node of an interworking wireless network to which a terminal is connected. To send. Thereafter, in step 408, the support process for the heterogeneous inter-network QoS support handoff procedure at the network connection relay node ends.

By performing the process of FIGS. 3 to 4, before performing the handoff between heterogeneous networks, the UE can grasp the cell information that can support the QoS desired by the handoff target interworking wireless network, thus selecting the actual handoff. The cell can then handoff with satisfactory QoS support.

In another embodiment of the present invention, the network connection relay node collects information of the base stations, determines a suitable base station that can best support the QoS desired by the terminal, and instructs the terminal to handoff to the base station.

Hereinafter, a method for supporting handoff between QoS supported heterogeneous networks according to another embodiment of the present invention will be described with reference to FIG. 5.

5 is a diagram illustrating a process of selecting a handoff target cell between different networks supporting QoS according to another embodiment of the present invention.

Referring to FIG. 5, when the terminal 501 wants to perform a handoff between heterogeneous networks, the terminal 501 transmits a vertical handoff request message 513 through an existing wireless connection 510. To send). Like the target probe request message, the vertical handoff request message includes an ID of the terminal, a Message ID, QoS information required by the terminal, and information on base stations that the terminal can receive.

The interworking radio network 1 506 that receives the vertical handoff request message 513 informs the network connection relay node 502 of a handoff request between heterogeneous networks of the terminal. The network connection relay node 502 grasps base station information included in the relay vertical handoff request message 513 and sends a forward vertical handoff response 515 message to the wireless network control / management nodes managing the base station. To pass. The forward vertical handoff request message 515 is composed of only base station information related to the corresponding interworking radio network transmitted by the terminal 501.

When each wireless network control / management node receives the forward vertical handoff request message 515, the wireless network control / management nodes determine whether the terminal 501 can satisfy the QoS required by grasping state information of base stations managed by the wireless network control / management node. Predict QoS information supported by the base station. This supportable QoS information is sent back to the network connection relay node 502 via a reply vertical handoff response message.

The network connection relay node 502 collects the supplemental handoff response messages 516 received from each wireless network control / management note to select a base station that can best support the QoS required by the terminal 501. do. Based on this, a forward vertical handoff direct message 517 is generated and transmitted to the interworking radio network 1 506 to which the terminal 501 is connected. In addition, the vertical handoff reserve message 518 notifies the terminal to perform a resource reservation procedure for QoS support to a target base station to perform handoff between heterogeneous networks. The forward vertical handoff direct message 517 includes an ID of the terminal, a Message ID, and target base station information to which the terminal 501 performs handoff between heterogeneous networks and QoS information that can be supported. The interworking radio network 1 506 receives the forward vertical handoff direct message 517, and instructs the terminal 501 to perform heterogeneous inter-network handoff through the vertical handoff direct message 519.

When the terminal 501 receives the vertical handoff direct message 519, the terminal 501 may identify a target base station capable of supporting the desired QoS. Therefore, the terminal 501 transmits the vertical handoff message 520 to the corresponding base station to establish a connection. Try. At this time, since the base station has already performed a resource reservation procedure from the network connection relay node 502 through the vertical handoff resub message 518, the terminal is connected to the terminal through the vertical handoff message 520. It is ready to support this desired QoS. The new interworking radio network 3 (508) confirming the terminal's network connection through the vertical handoff message 520 relays the result of the handoff performed by the terminal 501 through the vertical handoff indication message 521. The node 502 is notified.

When the network connection relay node 502 receives the vertical handoff indication message, the network connection relay node 502 recognizes that the network change of the terminal 501 is completed, and completes a handoff procedure between heterogeneous networks.

Hereinafter, an operation procedure of a main node according to another embodiment of the present invention will be described with reference to FIGS. 6 to 7.

6 is a diagram illustrating an operation procedure of a terminal according to another embodiment of the present invention.

Referring to FIG. 6, in step 601, the terminal proceeds to step 602 in order to perform handoff between heterogeneous networks, and the terminal proceeds to a network information collection procedure of collecting base station information using a network interface that the terminal can use. To perform. In this case, the terminal collects base station ID information that can be received by each network and reception strength of the corresponding base station signal. In step 603, the UE generates a vertical handoff request message based on the collected information and the QoS request information desired by the terminal, and performs a vertical handoff request transmission process. At this time, the timer is operated until the handoff response. In step 604, the terminal checks whether a vertical handoff direct message has been received. If the vertical handoff direct message is received as a result of the checking, in step 606, the terminal determines a base station for handoff according to the vertical handoff direct message. If the vertical handoff direct message is not received, the process proceeds to step 605.

In step 605, the terminal checks whether the timer has expired. If the timer expires as a result of the check, in step 607, the terminal selects a base station to be handed out according to the received signal strength, and proceeds to step 608, as in the existing handoff procedure. If the timer has not expired as a result of the check, the process returns to step 604.

In step 606, the terminal identifies QoS information that can be supported by the terminal through the handoff target base station information included in the received vertical handoff direct message, and the user determines his or her hand based on the target base station information. Figure out the base station to be turned off. In step 608, the terminal transmits a vertical handoff message to handoff the selected base station and the companion wireless network. The specific message type of the vertical handoff may be appropriately changed according to the interworking wireless network.

7 is a view showing the operation of the network connection relay node located in the interworking network core network according to another embodiment of the present invention.

Referring to FIG. 7, in step 701, a relay vertical handoff request message is received from a wireless network control / management node of a linked wireless network to which a terminal is connected. Here, the vertical handoff request message includes a target interworking radio network ID. In step 702, the network connection relay node transmits a vertical handoff request message to a radio network control / management node of an interworking radio network corresponding to the target interworking radio network ID, and is transferred to each radio network control / management node. The timer is activated with a wait time for response of the off request message. In step 703, the network connection relay node checks whether a reactive vertical handoff response message has been received. If there is no vertical handoff response message received as a result of the check, it is checked in step 704 whether the timer operation has expired. If the timer is in operation, the process returns to step 703. If the timer is finished, the process proceeds to step 707.

If the vertical handoff response message is received, the network connection relay node stores the supportable QoS information included in the vertical handoff response message received from the wireless network control / management node in step 705 to later support the vertical handoff direct message. It can be used when sending. If the result of the vertical handoff response message is stored, the process proceeds to step 706.

In step 706, the network connection relay node checks whether all response messages have been received. That is, it checks whether the number of vertical handoff response messages received by the terminal to the corresponding interworking wireless network is received. If the number of received response messages is smaller than the number of transmitted messages, the process returns to step 703.

When the number of response messages transmitted as a result of the check is received, the process proceeds to step 707. In step 707, the network connection relay node selects a base station and QoS information that can best support a desired QoS based on QoS information for each base station among the results stored in step 706. When the base station and QoS information are selected, the network connection relay node generates a vertical handoff direct message based on a result of the base station selection and transmits the generated vertical handoff direct message to the wireless network control / management node of the interworking wireless network to which the terminal is connected. . In step 709, the network connection relay node transmits a vertical handoff reserve message to inform the corresponding base station to perform a process such as resource reservation to support QoS for handoff of the terminal.

When the vertical handoff reserve message is transmitted, in step 710, the network connection relay node checks whether the terminal receives a vertical handoff indication message indicating that the terminal has connected from a new network by performing a handoff between heterogeneous networks. The vertical handoff indication message is transmitted to a network connection relay node in a wireless network control / management note when the terminal accesses through a new network.

If the vertical handoff indication message is received, the process proceeds to step 711. If the vertical handoff indication message is not received, the network connection relay node checks the timer in step 713 to determine the vertical handoff indication. Check if the message waiting time has expired. If the timer has expired, in step 714, the network connection relay node restores the resource reservation performed during the transmission of the vertical handoff reverse message to a previous value in order to stop the vertical handoff. If the timer has not expired, the process returns to step 710.

In step 711, the network connection relay node changes a network path to transmit data to the terminal, and in step 712, ends the process of supporting QoS between different networks.

By performing the process of FIG. 6 to FIG. 7, the terminal can perform the handoff to the base station selected by the network connection relay node to the most suitable base station supporting the desired QoS.

8 is a diagram illustrating a procedure in the case of successful vertical handoff according to another embodiment of the present invention.

Referring to FIG. 8, in step 808, the terminal 801 determines a handoff when the signal of the base station it receives is weakened, and proceeds to step 808 to transmit a vertical handoff request message to the WLAN 802. . Upon receiving the vertical handoff request message, in step 812 to 814, the WLAN 802 transmits a relay vertical handoff request message to the interworking network core network 806 through the WAG. The vertical handoff request message includes a QoS parameter desired by the terminal, base station information, and message ID.

In step 816, the interworking network core network 806 finds the corresponding SGSN using the base station information of the message and the mapping table provided by the interworking network, and transmits a vertical handoff request message to the SGSN 905 in step 818. Upon receiving the vertical handoff request message, the SGSN 805 transmits the vertical handoff request message to the corresponding RNC 804 using the BSSID and its mapping table in step 818. The vertical handoff request message includes information of the terminal, which is used to confirm whether the handoff is normally performed. In steps 824 to 826, the RNC 804 receives a response to the handoff request from the corresponding cell (one or more), and puts it in the vertical handoff response message to the interworking network core network 806 through the SGSN 805. send. The vertical handoff response message includes a cell scramble code.

In step 828, the interworking network core network 806 receives the vertical handoff response mesh to select a cell that best fits the QoS parameters desired by the terminal. In steps 830 to 832, the interworking network core network 806 transmits a handoff reserve message to the RNC 804 through the SGSN 805. In step 834 to 836, the RNC 805 prepares for handoff and transmits the response to the interworking network core network 806 via the SGSN 805 in a vertical handoff reserve response message. Then, the interworking network core network 806 transmits a relay vertical handoff direct message to the terminal 801 through the WAG 803 in steps 838 to 842.

The terminal receiving the relay vertical handoff direct message performs a handoff to the cell at step 844. If it is determined in step 846 that the handoff is performed, the RNC 804 transmits a vertical handoff indication message to the interworking network core network 806 through the SGSN 805 in steps 848 to 850.

9 is a diagram illustrating a procedure when a vertical handoff fails according to another embodiment of the present invention. Here, it is assumed that the terminal 901 connected to the WAG 903 and receiving a signal intends to hand off to the RNC 904 of the target interworking network.

Referring to FIG. 9, in step 908, the terminal 901 determines a handoff when a signal of a base station it receives is weakened, and proceeds to step 910 to transmit a vertical handoff request message to the WLAN 902. . Upon receiving the vertical handoff request message, in step 912 to 914, the WLAN 902 transmits a relay vertical handoff request message to the interworking network core network 906 through the WAG 903. The vertical handoff request message includes a QoS parameter desired by the terminal, base station information, and message ID.

In step 916, the interworking network core network 906 finds the corresponding SGSN using the base station information of the message and the mapping table provided by the interworking network, and transmits a vertical handoff request message to the SGSN 905 in step 918. Upon receiving the vertical handoff request message, the SGSN 805 transmits the vertical handoff request message to the corresponding RNC 904 using the BSS ID and its mapping table in step 920. The vertical handoff request message includes QoS information of the terminal, which is used to confirm whether the handoff is normally performed. In steps 924 to 926, the RNC 904 receives a response to the handoff request from the corresponding cell (one or more), and puts the vertical handoff response message on the interworking network core network 906 through the SGSN 905. To send. The vertical handoff response message includes a cell scramble code.

In step 928, the interworking network core network 906 receives the vertical handoff response message and selects a cell that best fits the QoS parameters desired by the terminal. In steps 930 to 932, the interworking network core network 906 transmits a handoff reserve message to the RNC 904 through the SGSN 905. In steps 934 to 936, the RNC 905 prepares for handoff, and transmits the response to the interworking network core network 906 via the SGSN 905 in a vertical handoff reserve response message. Then, the interworking network core network 906 transmits a relay vertical handoff direct message to the terminal 901 through the WAG 903 in steps 938 to 942. Thereafter, in step 948, if the interworking network core network 906 does not receive the vertical handoff indication message from the RNC 904 for a predetermined time, it generates a timeout. Thereafter, in steps 905 to 952, the interworking network core network 906 transmits a vertical handoff release message indicating the release of the vertical handoff through the SGSN 905.

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 present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the appended claims, but also by the equivalents of the claims.

In the present invention that operates as described in detail above, the effects obtained by the representative ones of the disclosed inventions will be briefly described as follows.

According to the present invention, when handoffing on a heterogeneous network, the UE notifies the UE of a cell supporting QoS requested by the UE in advance, thereby minimizing packet reception delay and packet loss due to handoff of the UE and not knowing QoS support information. By reducing the number of unnecessary handoffs that can occur, there is an effect of supporting stable service use.

Claims (10)

In the method of performing a handoff to a heterogeneous network that supports the desired QoS of the terminal connected to the core network of the interworking network through the interlocking wireless network, Collecting information of base stations that can be received by the terminal from a neighboring network and receiving strength of a base station signal; Generating a target probe request message including information on the collected base stations and QoS information desired by the terminal and transmitting the generated target probe request message to the interworking wireless network; Checking whether a target probe response message corresponding to the target probe request message is received; Receiving the target probe response message, checking whether the target probe response message includes base station information on at least one target base station capable of supporting a desired QoS of the terminal; And determining the target base station based on the base station information and handing off to the determined target base station if there is base station information capable of supporting the desired QoS as a result of the checking. The method of claim 1, If the target probe response message is not received within a predetermined time after transmitting the target probe request message, determining a base station to be handed off according to a reception strength of the collected base station signal; How to do off. The method of claim 1, wherein the target probe response message, And performing reception strength and QoS information of the at least one target base station. The method of claim 1, wherein the checking is performed. If there is no base station information for a target base station capable of supporting a desired QoS, the terminal determines a handoff target according to the received strength of the collected base station signal. A method for performing handoff between heterogeneous networks supporting a desired QoS by a mobile station through an interworking wireless network connected to a terminal and a network connection relay node connected to a wireless network control / management node of the interworking wireless network, Receiving, from the radio network control / management node, a relay target probe request message including base station information of base stations that the terminal can receive and QoS information desired by the terminal; Receiving the relay target probe request message, transmitting a forward target probe request message including base station information of the base station and QoS information of the terminal to the interworking wireless networks corresponding to the base station information; Checking whether a reply target probe response message including supportable QoS information for each base station is received from the corresponding interworking wireless networks; Storing the base station information satisfying the QoS information desired by the terminal included in the reply target probe response message when the reply target probe response message is received as a result of the checking; The wireless network control / forward target probe response message including base station information for at least one target base station capable of supporting QoS desired by the terminal by integrating supportable QoS information for each base station according to the reply target probe response message / And performing the transmission to the management node. delete A method for performing handoff between heterogeneous networks supporting a desired QoS by a mobile station through an interworking wireless network connected to a terminal and a network connection relay node connected to a wireless network control / management node of the interworking wireless network, Receiving a relay vertical handoff request message including QoS information desired by the terminal and base station information of base stations that the terminal can receive from the wireless network control / management node; Transmitting a forward vertical handoff request message including the base station information and the QoS desired by the terminal to the base stations corresponding to the base station information; Receiving, at the base station, a adaptive handoff response message including information on whether the terminal can support a desired QoS; Selecting a base station that can best support a desired QoS by the terminal according to the received reply handoff response message, and transmitting a vertical handoff direct message including base station information of the selected base station to the terminal; And performing handoff. The method of claim 7, wherein And transmitting a vertical handoff reserve message including QoS information of the terminal to a radio network control / management node of the selected base station. A method for performing handoff between heterogeneous networks supporting a desired QoS by a terminal connected to a core network of an interworking network through an interworking wireless network, Collecting base station information of base stations that can be received by the terminal from a neighboring network and reception strength of base station signals; Transmitting a vertical handoff request message including the collected base station information and QoS information desired by the terminal to the interworking wireless network; Receiving a vertical handoff direct message including base station information that best supports a desired QoS from the interworking wireless network; Determining a base station for handoff according to the vertical handoff direct message, and performing handoff between heterogeneous networks to the handoff target base station. The method of claim 9, After transmitting the vertical handoff request message, if the vertical handoff direct message has not been received for a predetermined time, the base station for handoff is determined according to the received strength of the collected base station, and the determined handoff target base station is transmitted. And performing handoff.

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