KR20110046218A - Method and apparatus for acquiring configuration information of target base station by source base station in wireless communication system and system therefor - Google Patents

Abstract

PURPOSE: A method and apparatus for acquiring target cell configuration information by a source cell in a wireless communication system provided to reduce the overhead for transferring setup information of an existing target cell. CONSTITUTION: A terminal transmits a measurement report including an identifying information of the terminal or a target cell to a source cell(502). If the target cell setup information is not included in the source cell(504) the source cell transmits a handover request message including the setup information of the target cell to a moving management entity(510). The moving management entity transmits a hand over request message including the target cell setup information to the target cell(512). The target cell transmits a handover response message in which the target setup information is included to the moving management entity(514).

Description

METHOD AND APPARATUS FOR ACQUISITION OF TARGET CELL CONFIGURATION INFORMATION BY A SOURCE CELL IN A WIRELESS COMMUNICATION SYSTEM AND SYTEM THEREOF}

The present invention relates to a wireless communication system. More particularly, the present invention relates to a method, an apparatus, and a system for acquiring configuration information of a target base station by a source base station in a wireless communication system.

Recently, a wireless communication system considering a femto cell has been studied. The femto cell is a small mobile communication base station that connects to a mobile communication core network through a broadband communication network installed indoors such as a home or an office, and provides coverage of a cell radius of 10 meters or less. A base station that can do it. Femtocells have various advantages to expand coverage in indoors, improve call quality, and efficiently provide a variety of wired and wireless convergence services.

For example, recently, the 3rd Generation Partnership Project (3GPP) considers a wireless communication system including a closed subscriber group (CSG) cell base station that can be accessed only by specific users, apart from the macro cell base station of the existing wireless communication system. .

The CSG cell refers to a cell that can be accessed only by terminals belonging to a specific group (ie, CSG) registered in advance to access the cell. The CSG cell may generally be a home cell installed in a narrow area such as an individual's home, or an enterprise / regional network cell installed in a wide area for an enterprise or a specific organization. The CSG cell is a concept very similar to the femto cell, hereinafter, the femto cell will be used in the same sense as the CSG cell.

Meanwhile, in a wireless communication system, in order for a source cell to acquire various necessary information of a target cell, such as an operation in which a terminal performs handover from a source cell to a target cell, the source cell is connected to the target cell from the terminal. It is common to get information about this. For example, in the case of a handover operation, the terminal analyzes a signal transmitted from the target cell to obtain a cell identifier (PCI), and a measurement report based on the acquired cell identifier transmitting a report) to the source cell enables the source cell to determine handover of the terminal.

However, this operation requires radio resources of the base station, and the terminal has an overhead for the operation. In addition, when the size of the measurement report of the UE increases in a state in which a channel state between the UE and the source cell is not good, such as a situation in which handover is required, the transmission success rate of the measurement report may be lowered, thereby degrading the performance of handover.

The present invention provides a method and apparatus for acquiring configuration information of a target cell by a source cell in a wireless communication system and a system thereof.

The present invention provides a method and apparatus and a system for acquiring information of a target cell by a source cell without using a measurement report of a terminal in a wireless communication system including a macro cell and a femto cell.

The present invention provides a method and apparatus for acquiring information of a target cell from a source cell through a core network in a wireless communication system including a macro cell and a femto cell, and a system thereof.

In a wireless communication system provided by the present invention, a method for obtaining configuration information between a source cell and a target cell may include: transmitting, by a terminal, a measurement report including identification information of the target cell to the source cell; If the handover is determined according to, if there is no configuration information of the target cell in the source cell, the source cell transmits a handover request message including a request for configuration information of the target cell to the mobility management entity; Transmitting, by the mobility management entity, a handover request message including a request for configuration information of the target cell to the target cell; and sending a handover response message including the configuration information of the target cell by the target cell. Transmitting to the mobile station, and wherein the mobility management entity includes configuration information of the target cell And transmitting a handover request message to the source cell, wherein the source cell transmits a handover request message including a request for configuration information of the target cell to the mobility management entity. And send a handover request message to the mobility management entity, wherein the handover request message includes identification information.

The method for acquiring configuration information of a target cell by a source cell in a wireless communication system provided by the present invention includes receiving a measurement report including identification information of the target cell from a terminal, and receiving the measurement report. If the handover is determined according to the present invention, if there is no configuration information of the target cell in the source cell, transmitting a handover request message including a request for configuration information of the target cell to a mobility management entity; And correspondingly, receiving a handover command including configuration information of the target cell obtained by requesting the target cell from the mobility management entity. The transmitting of the handover request message including the request for configuration information of the target cell to the mobility management entity may include transmitting a handover request message including identification information of the target cell to the mobility management entity. .

The method for providing configuration information to a source cell by a target cell in a wireless communication system provided by the present invention includes receiving a handover request message from a source cell via a mobility management entity, and receiving the received handover request. If the message includes the configuration information request of the target cell, transmitting a handover response message including the configuration information of the target cell to the source cell via the mobility management entity. The case where the configuration information request of the target cell is included in the received handover request message is characterized in that the identification information of the target cell is included in the received handover request message.

In a wireless communication system provided by the present invention, a method in which a source cell storing identification information of a target cell and configuration information of a target cell updates configuration information of the target cell may include: measuring by the terminal including identification information of the target cell; Transmitting a report to the source cell; and when the source cell determines handover according to the measurement report, the source cell informs a mobility management entity (MME) of the target cell identification information and the target cell. Transmitting a handover request message including configuration information of the MME; transmitting a handover request message including configuration information of the MME to the target cell; If the configuration information matches the current configuration information of the target cell, a handover response message including the current configuration information is sent. It comprises the step of transmitting the source cell, through a group MME.

Also, in a wireless communication system provided by the present invention, a method in which a source cell storing identification information of a target cell and configuration information of a target cell, updates configuration information of the target cell, includes identification information of the target cell from a terminal. When the handover is determined according to the process of receiving the measurement report, and the received measurement report, the handover request including the configuration information of the stored target cell through the Mobility Management Entity (MME) Transmitting to a target cell, receiving a handover response message for the handover request transmitted by the target cell through the MME, and if the handover response message includes configuration information of a new target cell, Updating the stored configuration information of the target cell with the configuration information of the new target cell.

Also, in the wireless communication system provided by the present invention, a method of updating, by a target cell, configuration information of the target cell to a source cell storing identification information of the target cell and configuration information of the target cell may include a mobility management entity. Receiving a handover request including configuration information of the target cell from an entity (MME); and if the configuration information of the received target cell and its configuration information match, the handover including the configuration information of the target cell; Transmitting a response message to the source cell through the MME.

Meanwhile, in the above methods, the source cell is a macro cell, the target cell is a femto cell, and the configuration information of the target cell is a UE group identifier (Closed Subscriber Group ID) accessible to the femto cell. .

Effects according to the configuration of the present invention are as follows.

In the present invention, since the terminal transmits the measurement report including the identification information of the target cell and does not include the configuration information to the source cell, the overhead of transmitting the configuration information of the existing target cell is reduced, and accordingly radio resources of the base station In this case, the transmission success rate of the measurement report is increased even in a state in which a channel state between the terminal and the source cell is not good as in a situation in which a handover is required, and thus the performance of the handover can be improved. In addition, even when the configuration information of the target cell stored in the source cell and the configuration information of the current target cell are different, the configuration information of the target cell can be efficiently updated in the source cell.

1 is a view for explaining the configuration of a wireless communication system including a macro cell base station and a femto cell base station to which the present invention is applied;
2 is a view for explaining a method for the terminal 200 to perform a handover from the source cell 202 to the target cell 206,
3 is a diagram illustrating an operation of a UE receiving configuration information of a target cell from a source cell while performing a handover according to the first embodiment of the present invention;
4 is a diagram illustrating an operation of a UE receiving configuration information of a target cell from a source cell while performing a handover according to the second embodiment of the present invention;
5 is a view for explaining the operation of the source cell 302 according to the first embodiment of the present invention;
6 is a view for explaining the operation of the target cell 304 according to the first embodiment of the present invention;
7 is a view for explaining the operation of the source cell 402 according to the second embodiment of the present invention;
8 is a view for explaining the operation of the target cell 404 according to the second embodiment of the present invention;
FIG. 9 is a diagram illustrating an operation of receiving configuration information of a target cell 904 from a source cell 902 while a terminal performs handover according to the third embodiment of the present invention;
10 is a view for explaining the operation of the source cell 902 according to the third embodiment of the present invention;
11 is a view for explaining the operation of the target cell 904 according to the third embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. It is to be noted that the same elements among the drawings are denoted by the same reference numerals whenever possible. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

Hereinafter, for convenience of description, the terminology of the 3GPP LTE (Long Term Evolution) system standard is used as a reference, but the use of these terms is merely for convenience of description, and the present invention is not limited to being applied to the LTE system. It should be noted that the present invention can be applied to similar systems. Also, in the present invention, a cell or a base station may be used in the same sense.

In addition, for convenience of description, a description will be made on the assumption of a handover situation in a wireless communication system including a macro cell and a femto cell, but this is not intended to limit the present invention, and the present invention is a source cell in a cellular wireless communication system. The same applies to the case of acquiring configuration information of a cell.

1 is a view for explaining the configuration of a wireless communication system including a macro cell base station and a femto cell base station to which the present invention is applied.

Referring to FIG. 1, a wireless communication network includes a macro cell base station 102, a femto cell base station (HeNB) 104, a mobility management entity (MME) 108, the MME 108 and a femto cell base station. And a femtocell base station gateway (HeNB GW) 106 and a user equipment (UE) 100 for connecting the UE. Meanwhile, the femtocell base station gateway 106 may not be included depending on the implementation method of the system.

The macro cell base station 102 is a base station that manages a macro cell. The macro cell base station 102 is connected to the terminal 100 through a radio channel and controls radio resources. For example, the macro cell base station 102 may generate and broadcast necessary control information in the macro cell as system information, or allocate radio resources to transmit and receive data or control information with the terminal 100. .

In addition, the macro cell base station 102 may receive the channel measurement information of the current cell and neighbor cells transmitted by the terminal 100 to determine the handover, and may command the handover accordingly. The macro cell base station 102 has a control protocol such as Radio Resource Control (RRC) protocol related to radio resource management.

Meanwhile, the femto cell base station 104 is a base station that manages a femto cell (or CSG cell) and is connected to a core network such as the MME 108 to provide a mobile communication service to the terminal 100. In addition, the femtocell base station 104 according to the present invention provides a mobile communication service only to a terminal registered to it, and broadcasts by including a CSG ID, which is information of a specific group that provides the service, in a SIB (System Information Block). do.

The MME 108 manages an idle terminal (idle) terminal, selects a PDN (Packet Data Network) gateway and serving gateway (not shown), and performs a function related to roaming and authentication. . In addition, the MME 108 according to the present invention may include configuration information (eg, CSG ID) for femto cell base stations to which each terminal can access in the form of a UE Allowed CSG List. have.

The femto cell base station gateway (HeNB GW) 106 serves to connect the MME 108 and the femto cell base station 104, and may not be separately installed according to an implementation method.

The terminal 100 may access the core network through the macro cell base station 102 or the femto cell base station 104. In this case, as an example, the terminal 100 receives and stores a UE Allowed CSG List from a core network entity (not shown), such as an OMA DM (Open Mobile Alliance-Device Management) server. In addition, the terminal 100 receives a system information block (System Information Block) broadcast from the femtocell base station 104 to check the identification information of each femtocell base station, and can be connected to itself compared to the access permission list The femto cell base station can be identified. In addition, the terminal 100 obtains a femto cell dedicated cell identifier (Physical Cell ID) from the macro cell base station 102 or the femto cell base station 104 to search for a synchronization channel (SCH), or You can measure it.

Hereinafter, for convenience of description, the macro cell base station 102 will be described as a serving base station, but the present invention can be equally applied to the case where the femto cell base station 104 is a serving base station. Meanwhile, in the description for the handover operation, the serving base station may be used as the same meaning as the source base station.

Then, prior to the description of the present invention, a conventional method of performing a handover from the source cell to the target cell will be described with reference to FIG. 2.

FIG. 2 is a diagram illustrating a method in which the terminal 200 performs handover from the source cell 202 to the target cell 206.

Referring to FIG. 2, in step 208, the terminal 200 transmits EUTRAN Cell Global Identification (ECGI) of the target cell and configuration information of the target cell, for example, a CSG ID to the source cell 202 through a measurement report. To pass. The ECGI is a unique identifier that can be mapped one-to-one with the target cell 206 to identify the target cell 206. In operation 210, the source cell 202 that has received the identification information and the configuration information of the target cell stores the received information.

Meanwhile, in step 212, the terminal 200 may perform another measurement report including identification information of the target cell, and in step 214, the source cell 202 may be based on the measurement report transmitted in step 208 or step 212. The handover of the terminal 200 is determined, and the handover request message including the identification information (ECGI) and the configuration information (target CSG ID) of the target cell stored in step 210 is transmitted to the MME 204. send.

The MME 204 checks whether the target cell configuration information (Target CSG ID) is included in the UE Allowed CSG List of the UE in step 216, and if so, handover of the UE. Continue, and if not included, stop handover. This process is called access control.

If the MME 204 determines to continue handover of the UE in step 216, the handover request including configuration information (Target CSG ID) of the target cell is transmitted to the target cell 206 in step 218. .

In step 220, the target cell 206 checks whether the received target cell configuration information (Target CSG ID) matches its configuration information (CSG ID). This is to check whether the configuration information (Target CSG ID) of the target cell transmitted by the terminal 200 is correct in step 208.

If the received target cell configuration information (Target CSG ID) does not match with its own CSG ID, the target cell 206 rejects the handover request of step 218, and if both match, the target cell 206 By allowing the handover, a handover response message is transmitted to the MME 204 in step 222.

After receiving the handover response message, the MME 204 commands the handover of the terminal 200 to the source cell 202 in step 224, and the source cell 202 receiving the handover command receives the handover command in step 226. 200 instructs handover to the target cell 206. In step 228, the terminal 200 performs an operation for performing a handover to the target cell 206.

According to the handover operation according to FIG. 2 described above, the terminal 200 transmits target cell configuration information (Target CSG ID) to the source cell 202 through the measurement report. However, such operation requires radio resources of the base station, and the terminal has an overhead for the operation. In particular, when the terminal 200 needs to perform a measurement report on the target cell configuration information (target CSG ID) as in step 208 when the handover of the terminal is needed, between the terminal 200 and the source cell 202. Since a measurement report message having a relatively large size is transmitted in a bad channel condition for transmission and reception, the transmission success rate of the measurement report message is lowered, and thus the handover performance of the terminal may be degraded.

Hereinafter, an embodiment in which a source cell acquires configuration information of a target cell in a wireless communication system including a femto cell will be described in detail. Embodiments of the invention include three embodiments.

In the first embodiment, the terminal does not include the configuration information of the target cell, the measurement report including the identification information of the target cell, the source cell transmits a handover execution request message including the target cell configuration information request to the MME In this manner, the configuration information of the target cell is obtained.

Meanwhile, in the second embodiment, the terminal does not include the configuration information of the target cell, the measurement report including the identification information of the target cell, the source cell does not include the configuration information of the target cell, the identification of the target cell The configuration information of the target cell is obtained by transmitting a handover request including the information to the MME.

In addition, in the third embodiment, when the source cell has already stored the identification information of the target cell, the terminal reports the measurement including the identification information of the target cell, and the source cell makes a handover request to the target cell through the MME. When the identification information of the target cell stored in the source cell is different from the configuration information of the current target cell, the changed configuration information is received from the target cell, and the previously stored configuration information is updated with the changed configuration information.

3 is a diagram illustrating an operation of a UE receiving configuration information of a target cell from a source cell while performing a handover according to the first embodiment of the present invention.

In step 308, the terminal 300 transmits a measurement report including the identification information of the target cell to be handed over to the source cell 302. The source cell 302 checks whether the configuration information (CSG ID) of the target cell is stored using the identification information (ECGI) of the target cell, and if the configuration information is stored, steps 214 to 228 of FIG. 2. Handover of the terminal is performed through the operation of the step.

In FIG. 3, it is assumed that the source cell 302 does not store setting information of the target cell. In this case, the source cell 302 transmits a handover request message including identification information (ECGI) of the target cell to the MME 304 to request configuration information of the target cell in step 310.

In step 312, the MME 304 transmits a handover request message including the transmitted target cell configuration information request to the target cell 306. The request for configuration information of the target cell of the MME 304 may be implemented by including an indicator indicating a target cell configuration information request directly in the handover request message.

In step 314, the target cell 306 transmits a handover performance response message including its configuration information, that is, a CSG ID, to the MME 304, and the MME 304 sets the received target cell in step 318. A handover perform command including information is sent to the source cell 302.

The source cell 302 acquires both target cell identification information (ECGI) and target cell configuration information (Target CSG ID) through steps 308 and 318, and stores the obtained information therein in step 320. In step 322, the source cell 302 receiving the handover command instructs the terminal 300 to perform a handover to the target cell 306. In step 324, the terminal 300 receives the handover command. As a result, handover is performed to the target cell 306.

According to the first embodiment described above, when the terminal 300 transmits the measurement report including the ECGI of the target cell 306 and does not include the CSG ID to the source cell 302, the source cell 302 Since the handover performance request message including the target cell configuration information request is transmitted to the MME 304 to obtain configuration information of the target cell 306, overhead of the terminal can be reduced, and the source cell 302 Since no radio resource is used and the size of the measurement report message is reduced, the success rate of the measurement report message is increased, thereby improving handover performance.

FIG. 4 is a diagram for describing an operation of receiving, by a UE, configuration information of a target cell from a source cell while performing a handover according to the second embodiment of the present invention.

Referring to FIG. 4, in step 408, the terminal 400 transmits a measurement report including the identification information (ECGI) of the target cell to the source cell 402. The source cell 402 checks whether the configuration information (CSG ID) of the transmitted target cell is stored using the identification information of the target cell, and if the configuration information is stored, steps 214 to 228 of FIG. 2. Handover of the terminal is performed through the operation of.

In FIG. 4, it is assumed that the source cell 402 does not store setting information of the target cell. Accordingly, the source cell 402 transmits a handover request message including the identification information (ECGI) of the target cell to the MME 304 in step 410. In step 412, the MME 404 transmits a handover request message including the ECGI to the target cell 406. Meanwhile, the handover request message transmitted by the MME 304 does not include a direct indicator for requesting configuration information of the target cell. The target cell 406 is made by an advance appointment between the MME 404 and the target cell 406. ) May be implemented to regard a handover request message that does not include the direct indicator as a request for configuration information of a target cell.

In step 414, the target cell 406 determines that its own configuration information (CSG ID) is not included in the handover request message transmitted in step 412, and considers it as an indicator requesting configuration information. Send a handover response message containing the ID to the MME 404.

In step 416, the MME 404 performs access control using the transmitted CSG ID. That is, if the target CSG ID transmitted in step 414 is included in the UE Allowed CSG List of the UE 400 included in the MME 404, the UE continues to perform handover. Stop handover.

Since the target CSG ID is received in step 414, the MME 404 will determine that the handover will continue. In step 418, the handover command including the target CSG ID is transmitted to the source cell 402. .

The source cell 402 acquires both target cell identification information (ECGI) and target cell configuration information (Target CSG ID) through steps 408 and 418, and stores the obtained information therein in step 420. After receiving the handover command, the source cell 402 instructs the terminal 400 to perform a handover to the target cell 406 in step 422, and in step 424, the terminal 400 receives the handover command. As a result, handover is performed to the target cell 406.

Comparing the operation of the second embodiment of FIG. 4 with the operation of the first embodiment of FIG. 3, the terminal 400 reports the measurement report including the ECGI of the target cell and not including the CSG ID. ), The source cell 402 also includes an ECGI and does not include a CSG ID, which is the same as the source cell 302 directly requesting target cell configuration information in FIG. 3. Function can be performed.

5 is a view for explaining the operation of the source cell 302 according to the first embodiment of the present invention.

In step 502, the source cell 302 receives the measurement report including the identification information (ECGI) of the target cell from the terminal 300, and determines whether to handover the terminal using the received measurement report in step 504 .

In step 506, it is determined whether the target cell has the configuration information of the target cell using the identification information (ECGI) of the target cell. If it does not have the configuration information of the target cell, the flow proceeds to step 508 to request the target cell configuration information. Include in the handover request message. In step 510, the handover request message is transmitted to the MME 304.

In step 512, when the handover command message corresponding to the handover request message is received from the MME 304, it is determined in step 514 whether the configuration information of the target cell is included in the handover command message. If the handover command message includes the configuration information of the target cell, the flow proceeds to step 516 to store the identification information and the configuration information of the target cell in the source cell 302. In operation 518, the source cell 302 commands the terminal 300 to perform handover.

On the other hand, if the source cell has the configuration information of the target cell in step 506 proceeds directly to step 510 and transmits a handover request message to the MME (304). In this case, the target cell configuration information request is not included in the handover execution request message. In this case, since the handover command received from the MME 304 does not include the configuration information of the target cell in step 514, the process proceeds directly to step 518 to transmit the handover command to the terminal.

6 is a view for explaining the operation of the target cell 304 according to the first embodiment of the present invention.

In step 602, the target cell 306 receives a handover request message of the terminal 300 from the MME 304. In step 604, if the handover performance request message includes the configuration information request indicator of the target cell, the flow proceeds to step 606 to include the target cell configuration information in the handover performance response message. In step 608, a handover performance response message including the target cell configuration information is transmitted to the MME 304.

On the other hand, if the target cell configuration information request indicator is not included in the handover request message received in step 604, the process proceeds directly to step 608 and transmits a handover performance response message not including the target cell configuration information to the MME 608. do.

7 is a view for explaining the operation of the source cell 402 according to the second embodiment of the present invention.

In step 702, the source cell 402 receives a measurement report including the identification information (ECGI) of the target cell from the terminal 400, and determines whether the terminal is handed over using the received measurement report in step 704. .

In step 706, it is determined whether the target cell has the configuration information of the target cell by using the identification information (ECGI) of the target cell. Include in the over-run request message. In step 710, the handover request message is transmitted to the MME 304.

Thereafter, in step 712, a handover command message corresponding to the handover request message is received from the MME 304. However, in this case, since the handover command received from the MME 304 does not include the configuration information of the target cell in step 714, the process proceeds directly to step 718 to transmit the handover command to the terminal.

If the source cell does not have the configuration information of the target cell in step 706, the process proceeds directly to step 710 and transmits a handover request message to the MME 304. In this case, the target cell configuration information request is not included in the handover execution request message. In this case, since the handover command message includes the configuration information of the target cell in step 714, the flow proceeds to step 716 to store the identification information and the configuration information of the target cell in the source cell 302. In operation 718, the source cell 302 commands the terminal 300 to perform handover.

8 is a view for explaining the operation of the target cell 404 according to the second embodiment of the present invention.

In step 802, the target cell 406 receives a handover request message of the terminal 400 from the MME 404. In step 804, if the handover performance request message includes configuration information of the target cell, the flow proceeds directly to step 808 to transmit a handover performance response message to the MME 304. On the other hand, if the target cell configuration information is not included in the handover execution request message received in step 804, the flow proceeds directly to step 806 to include the target cell configuration information in the handover performance response message. In step 808, the MME 408 transmits a handover performance response message that does not include the target cell configuration information.

FIG. 9 is a diagram illustrating an operation of receiving, by a UE, configuration information of a target cell from a source cell while performing a handover according to the third embodiment of the present invention.

As mentioned above, the third embodiment assumes a situation in which the source cell 902 stores identification information and configuration information of the target cell. However, the manner in which the source cell 902 obtains identification information and configuration information of the target cell is not particularly limited. Accordingly, the present invention may be based on the conventional method described with reference to FIG. 2 or may be based on the method of the first and second embodiments of the present invention described above.

In addition, in the third embodiment, it is assumed that the target cell 906 is a CSG cell but supports not only a terminal registered to the terminal but also a terminal not registered to the terminal. That is, the CSG cell operates in a general case to support a terminal registered to the CSG cell, but in some cases, the CSG cell may be set to a mode that supports all terminals other than the registered user. The third embodiment assumes such a situation. For convenience of explanation, the former will be referred to as "CSG mode" and the latter will be referred to as "hybrid mode".

Referring to FIG. 9, operation 908 indicates that the source cell 902 previously stores identification information of the target cell and configuration information of the target cell. In step 910, the terminal 900 reports a measurement including identification information of the target cell, and in step 912, the source cell 902 performs handover of the terminal 900 based on the measurement report transmitted in step 910. If so, in step 908, a handover request message including identification information (ECGI) and target cell configuration information (target CSG ID) of the stored target cell is transmitted to the MME 904.

If the target cell 906 operates in the CSG mode, the MME 904 includes the target cell configuration information (Target CSG ID) in the UE Allowed CSG List in step 914. If it is included, the handover of the terminal is continued if it is included, and if it is not included, the handover is stopped. This process is called access control.

On the other hand, if the target cell 906 operates in a hybrid mode, the MME 904 determines to perform handover immediately without having to perform the access control of step 914 because the target cell 906 supports all the terminals. do. Meanwhile, the MME 904 may know the operation mode of the target cell 906 through operation mode information received from the source cell 902. For example, the source cell 902 may include operation mode information of the target cell 906 in the handover request message of step 912.

If the MME 904 determines to continue handover of the UE in step 914, the MME 904 transmits a handover request that includes configuration information (Target CSG ID) of the target cell in step 916. 906).

In step 918, the target cell 906 checks whether the received target cell configuration information (Target CSG ID) matches its configuration information (CSG ID). This is to check whether the configuration information (Target CSG ID) of the target cell transmitted by the terminal 900 is correct in step 918.

The operation of the target cell 906 after validation depends on the mode of operation of the target cell 906. First, the case of operating in the hybrid mode will be described. In FIG. 9, the operation after step 918 assumes a situation in which the target cell 906 operates in a hybrid mode.

Since the target cell 906 operates in a hybrid mode, handover should be allowed even if the configuration information (Target CSG ID) of the target cell received in step 918 does not match its configuration information (CSG ID). Accordingly, the target cell 906 transmits a handover response message including its configuration information (CSG ID) to the MME 904 in step 920.

For reference, when the configuration information of the target cell received from the MME 904 by the target cell 906 does not match with the current configuration information thereof, the target cell 906 changes its configuration information by the target cell 906. This can happen in the same example. For example, the target cell 906 was operating in the CSG mode before the current time point, and the setting information used was CSG ID 1, and the hybrid cell was operating in the hybrid mode after the current time point, and the setting information was changed to the CSG ID 2 at this time. Suppose you did. In this case, if the UE 906 acquires the CSG ID 1 and reports the measurement to the source cell using the CSG ID 1, the target cell 906 has the configuration information (ie, the CSG ID 1) received from the MME 904 and the current self. Configuration information (ie, CSG ID 2) does not match. In this case, the target cell 906 needs to inform the source cell 902 of its own configuration information. Therefore, as described above, the target cell 906 transmits a handover response including its own configuration information to the MME 904 even when the configuration information received from the MME 904 does not match its own configuration information.

Referring back to FIG. 9, if the MME 904 that has received the handover response message of step 920 includes the configuration information of the target cell in the handover response message, the MME 904 informs the source cell 902 of the target cell in step 922. Send a handover command including configuration information. Thereafter, in step 924, the configuration information of the target cell stored in step 908 is updated with the configuration information of the new target cell received in step 911. Further, the source cell 902 instructs the terminal 900 to handover to the target cell 906 in step 926, and the terminal 900 performs an operation for performing handover to the target cell 906 in step 928. To perform.

Meanwhile, although not shown in FIG. 9, a case in which the target cell 906 operates in the CSG mode will be described. If the target cell 906 does not match the configuration information (CSG ID) of the target cell received in step 918, the target cell 906 performs the handover request in step 916. If it is rejected, and if they match, handover is allowed to be sent to the MME 904 in step 920. In this case, when the handover request is rejected, the target cell 906 may transmit a handover rejection message to the MME 904 and transmit its current configuration information (CSG ID) to the handover rejection message. The MME 904 transmits a handover rejection message including the configuration information of the target cell 906 to the source cell 902 in step 922, and receives the configuration information of the target cell in step 911. It can be updated with the setting information of the target cell.

10 is a view for explaining the operation of the source cell 902 according to the third embodiment of the present invention.

In step 1002, the source cell stores identification information of the target cell and configuration information of the target cell. There is no particular limitation on the manner in which the source cell acquires identification information and configuration information of the target cell. Therefore, the present invention may be based on the conventional method described with reference to FIG.

In step 1004, if the measurement report including the identification information of the target cell is received from the terminal, and in step 1006 it is determined to handover the terminal to the target cell using the measurement report, in step 1008 the target cell stored in step 1002 A handover request message including the identification information and the configuration information of the target cell is transmitted to the MME. The MME will then send a handover request message containing the identification information of the target cell to the target cell.

In step 1010, a response to the request, that is, a handover response message is received through the MME to the handover transmitted by the target cell.

In step 1012, if the configuration information of the target cell is included in the response to the handover request, the flow proceeds to step 1014 to update the configuration information of the target cell. That is, the configuration information of the target cell previously stored in step 1002 is updated with the configuration information of the new target cell included in the response message for the handover request. In operation 1016, the subsequent operation is performed according to the handover response message. That is, if the handover response message is the response message of the handover permission, the terminal instructs handover. If the handover response message is the response message of the handover rejection, the terminal does not instruct the handover.

On the other hand, if the configuration information of the target cell is not included in the handover response message in step 1012, the flow proceeds directly to step 1016 to perform the operation according to the type of the handover response message.

11 is a view for explaining the operation of the target cell according to the third embodiment of the present invention.

In step 1102, the target cell receives a handover request message including configuration information of the target cell from the MME.

In step 1104, if it is determined whether the received configuration information of the target cell is identical with the configuration information of the mobile station, the flow proceeds to step 1106, and a response message of handover acceptance is transmitted to the source cell through the MME. Proceed to

In step 1108, the target cell generates a handover response message including its configuration information and transmits it to the source cell through the MME. If the target cell is operating in hybrid mode, the handover response message will be a response message of a handover grant. If the target cell is operating in CSG mode, the handover response message will be a response message of handover rejection. .

Claims (21)

A method of obtaining configuration information between a source cell and a target cell in a wireless communication system,
Transmitting, by the terminal, a measurement report including identification information of the target cell to the source cell;
If the source cell determines the handover according to the measurement report, if there is no configuration information of the target cell in the source cell, the source cell includes a handover request message including a request for configuration information of the target cell from a mobility management entity. Sending a message,
Transmitting, by the mobility management entity, a handover request message including a request for configuration information of the target cell to the target cell;
Transmitting, by the target cell, a handover response message including configuration information of the target cell to the mobility management entity;
And transmitting, by the mobility management entity, a handover command including configuration information of the target cell to the source cell. The method of claim 1, wherein the source cell transmits a handover request message including a request for configuration information of the target cell to the mobility management entity.
And the source cell transmits a handover request message including identification information of the target cell to the mobility management entity. 3. The method according to claim 1 or 2,
The source cell is a macro cell,
The target cell is a femto cell,
The configuration information of the target cell is a method of obtaining configuration information between a source cell and a target cell, characterized in that a terminal group identifier (Closed Subscriber Group ID) accessible to the femto cell. A method for a source cell to obtain configuration information of a target cell in a wireless communication system,
Receiving a measurement report including identification information of the target cell from a terminal;
If the handover is determined according to the received measurement report, if there is no configuration information of the target cell in the source cell, transmitting a handover request message including a configuration information request of the target cell to a mobility management entity;
And receiving, by the mobility management entity, a handover command including configuration information of the target cell obtained by requesting the target cell in response to the handover request message. How to. The method of claim 4, wherein the transmitting of the handover request message including the configuration information request of the target cell to the mobility management entity comprises:
And transmitting a handover request message including identification information of the target cell to the mobility management entity. The method according to claim 4 or 5,
The source cell is a macro cell,
The target cell is a femto cell,
And the configuration information of the target cell is a Closed Subscriber Group ID that is accessible to the femto cell. A method for providing configuration information to a source cell by a target cell in a wireless communication system, the method comprising:
Receiving a handover request message from a source cell via a mobility management entity;
If the received handover request message includes a configuration information request of the target cell, transmitting a handover response message including configuration information of the target cell to the source cell via the mobility management entity; The target cell provides configuration information to the source cell. The method of claim 7, wherein the configuration information request of the target cell is included in the received handover request message.
And the identification information of the target cell is included in the received handover request message. The method according to claim 7 or 8,
The source cell is a macro cell,
The target cell is a femto cell,
The configuration information of the target cell is a terminal group identifier (Closed Subscriber Group ID) accessible to the femto cell, characterized in that the target cell provides configuration information to the source cell. In the method of the source cell storing the identification information of the target cell and the configuration information of the target cell in a wireless communication system to update the configuration information of the target cell,
Transmitting, by the terminal, a measurement report including identification information of the target cell to the source cell;
When the source cell determines the handover according to the measurement report, the source cell includes a handover request message including identification information of the target cell and configuration information of the target cell to a mobility management entity (MME) Sending a message,
Transmitting a handover request message including configuration information of the MME to the target cell;
If the target cell matches the configuration information of the transmitted target cell and the current configuration information of the target cell, transmitting a handover response message including the current configuration information to the source cell through the MME. Updating the setting information of the target cell. The method of claim 10,
The source cell is a macro cell,
The target cell is a femto cell,
The configuration information of the target cell is a method of updating configuration information of a target cell, characterized in that the terminal group identifier (Closed Subscriber Group ID) accessible to the femto cell. 12. The method of claim 11,
If the target cell operates in a hybrid mode supporting a terminal not registered in the target cell, the handover response message is a response message of a handover permission. 12. The method of claim 11,
If the target cell operates in a CSG mode supporting a terminal registered with the target cell, the handover response message is a response message of a handover rejection. In the method of the source cell storing the identification information of the target cell and the configuration information of the target cell in a wireless communication system to update the configuration information of the target cell,
Receiving a measurement report including identification information of the target cell from a terminal;
When a handover is determined according to the received measurement report, transmitting a handover request including configuration information of the stored target cell to the target cell through a mobility management entity (MME);
Receiving a handover response message for the handover request transmitted by the target cell through the MME;
If the handover response message includes configuration information of a new target cell, updating configuration information of the stored target cell with configuration information of the new target cell. The method of claim 14,
The source cell is a macro cell,
The target cell is a femto cell,
The configuration information of the target cell is a method of updating configuration information of a target cell, characterized in that the terminal group identifier (Closed Subscriber Group ID) accessible to the femto cell. 16. The method of claim 15,
If the target cell operates in a hybrid mode supporting a terminal not registered in the target cell, the response to the handover request is a response message of a handover permission. 16. The method of claim 15,
If the target cell operates in a CSG mode supporting a terminal registered with the target cell, the handover response message is a response message of a handover rejection. A method for updating a configuration information of a target cell by a target cell in a wireless communication system, the source cell storing identification information of the target cell and configuration information of the target cell,
Receiving a handover request including configuration information of the target cell from a mobility management entity (MME);
If the received configuration information of the target cell and its own configuration information match, updating the configuration information of the target cell including transmitting a handover response message including the own configuration information to the source cell through the MME. How to. 19. The method of claim 18,
The source cell is a macro cell,
The target cell is a femto cell,
The configuration information of the target cell is a method of updating configuration information of a target cell, characterized in that the terminal group identifier (Closed Subscriber Group ID) accessible to the femto cell. The method of claim 19,
If the target cell operates in a hybrid mode supporting a terminal not registered in the target cell, the handover response message is a response message of a handover permission. The method of claim 19,
If the target cell operates in a CSG mode supporting a terminal registered with the target cell, the handover response message is a response message of a handover rejection.

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