KR20100003664A - Method and system for managing information of neighbor basestations using terminal accomplishing connection setting or handover - Google Patents

Abstract

The present invention relates to a neighbor base station information management method and management system in a broadband wireless communication system, and transmits a message requesting information of a previous base station connected before handover or network entry to a terminal that has completed handover or has completed network entry, By determining whether to update the neighboring base station information using the previous base station information response message from the terminal, the configuration of performing the neighbor base station information update using the previous base station information that the terminal has.

Description

METHOD AND SYSTEM FOR MANAGING INFORMATION OF NEIGHBOR BASESTATIONS USING TERMINAL ACCOMPLISHING CONNECTION SETTING OR HANDOVER}

The present invention relates to a neighbor base station information management method and management system in a broadband wireless communication system. More particularly, the present invention relates to receiving base station information before handover or network entry from a terminal that has completed a handover procedure or completed a network entry procedure. To update neighbor base station information.

In the broadband wireless access (BWA) communication system, a next-generation communication system, research is being actively conducted to support high-speed services in the form of guaranteeing mobility and QoS. For example, a representative communication system is the Institute of Electrical and Electronics Engineers (IEEE) 802.16e communication system.

In order to guarantee mobility and to support seamless service, an 802.16e communication system moves a base station of a current cell, that is, a serving base station, from a serving base station to another cell in order to support a seamless service. It supports handover to set call.

In order to handover, the terminal should be able to know the information of the neighboring base station to move in advance. The ASN-GW (Access Service Network Gateway) transmits information such as a list of neighbor BSs (NBL, Neighbor BS List) and DCD / UCD information to which the UE can hand over to the base station, so that the base station knows the information of the neighbor base station. To be able. In addition, the base station periodically transmits a Mobile Neighbor Advertisement (MOB_NBR-ADV) message to the terminal by using the neighbor base station list, so that the terminal can know the neighbor BS information.

On the other hand, the next generation wireless communication system is to apply a wireless SC / SO (Self Configuration / Self Optimization) technology to the base station, so that the base station itself can detect the change in the surrounding communication environment to perform the procedure to automatically change the base station settings . In addition, as communication service capacity is required to increase due to an increase in communication services, a technology for gradually miniaturizing cell sizes such as ubicells and femtocells has been developed to increase cell coverage and wireless capacity. The total number of base stations, including those, is increasing rapidly.

As the small base stations become common, not only many base stations exist in the ASN-GW but also more and more base stations are newly added or removed. As the base stations connected to each base station are changed as described above, the communication environment of each base station also changes frequently, so that the base stations having the SC / SO function change the base station setting frequently in accordance with the changed communication environment. In addition, for example, when there are mixed base stations having different manufacturers or different standards, the ASN-GW connected to each base station may not interwork with each other due to differences in specifications, even though this is a neighboring base station There may be a base station that the ASN-GW does not understand.

As such, a case may occur in which the ASN-GW does not know the base station information. In this case, the neighbor base station list is not included in the MOB_NBR-ADV message transmitted by the serving base station to the terminal for handover. Accordingly, the terminal cannot handover to the neighbor base station not included in the MOB_NBR-ADV message, and the base station scan is performed for other neighbor base stations having a poor channel state included in the message, thereby causing a delay in handover. In addition, there is a problem that QoS is degraded by handover to a base station having a poor channel state.

In addition, even if the Neighbor_BS_Resource_Status_Update message transmitted from the ASN-GW to the base station to update the neighboring base station information is lost or an error occurs during transmission, there is no process for re-requesting the update message, so there is no method for correcting the error.

As such, in order to effectively support handover of the terminal, it is important to keep the neighbor base station information held by the base station accurate and up to date.

In order to solve the above problem, an object of the present invention is to provide an apparatus and method for updating the neighbor base station information of the base station by using the base station information that the terminal has in a broadband wireless communication system.

Another object of the present invention is to provide an apparatus and method for correcting a case where a neighbor base station information update message is lost or has a wrong value during transmission in a broadband wireless communication system.

Another object of the present invention is to provide an apparatus and method for updating a neighbor base station list and information of a base station by using a terminal newly entering a network, performing a handover, or roaming from another system in a broadband wireless communication system. In providing.

According to a first aspect of the present invention for achieving the objects of the present invention, in a method for managing neighboring base station information in a broadband wireless communication system, a transfer of a handover or a network entry to a terminal before handover or network entry Transmitting a message requesting base station information, determining whether to update neighboring base station information by using a previous base station information response message received from the terminal, and performing neighboring base station information updating when the neighboring base station information is required to be updated. Provided is a method for managing neighboring base station information comprising the steps.

According to the second aspect of the present invention, the step of determining whether to update the neighboring base station information, the step of determining whether or not the previous base station information in the previous base station information response message, if the previous base station information in the response message, Determining whether the previous base station information is included in a previously stored neighbor base station list, and determining that the neighbor base station information needs to be updated if the previous base station information is not included in the neighbor base station list. A method of managing base station information is provided.

According to a third aspect of the present invention, the neighbor base station information updating step includes: requesting neighbor base station information to be updated to an ASN-GW; receiving the requested neighbor base station information through the ASN-GW; It provides a neighbor base station information management method comprising the step of updating the neighbor base station information using the neighbor base station information.

According to a fourth aspect of the present invention, in a terminal for managing neighbor base station information in a broadband wireless communication system, when the connection with the first base station is disconnected, the storage unit stores base station information of the first base station as previous base station information; After the connection with the first base station is disconnected, the network re-entry procedure is performed to the second base station, and upon completion of network entry, if the previous base station information request message is received from the second base station, the previous base station information is transmitted as the previous base station information response message. It provides a terminal, including a control unit. In addition, when the first base station and the second base station performs a handover, a storage unit for storing the base station information of the first base station as the previous base station information, and performs the handover from the first base station to the second base station, When the previous base station information request message is received from the second base station after the completion of over provides a terminal including a control unit for transmitting the previous base station information in the previous base station information response message.

According to the fifth aspect of the present invention, upon completion of the handover or disconnection of the network, a terminal for storing the previously accessed base station information as a previous base station information for a predetermined time and the terminal for completing the handover or network entry procedure The base station transmits an information request message, and determines whether to update neighboring base station information from previous base station information received from the terminal, and provides an adjacent base station information management system.

According to an embodiment of the present invention, when the neighboring base station information of the base station is changed, such as the addition or removal of the neighboring base station, the neighboring base station information that the ASN-GW or the base station does not grasp using the neighboring base station information held by the terminal is changed. You can update it.

In addition, according to another embodiment of the present invention, when a message transmission about the neighbor base station information fails or an error occurs through the update of the neighbor base station information, the error may be corrected by retransmitting the neighbor base station information.

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

1 is a diagram schematically illustrating a configuration of a wireless communication system supporting handover of a terminal according to an embodiment of the present invention.

Referring to FIG. 1, the terminal 100 moves from a region currently managed by a base station (BS) 1 (110) to a cell managed by a BS2 (120) adjacent to a base station, and disconnects from the BS1 (110). The BS2 120 performs a handover procedure for establishing a new connection. The terminal 100 receives the DCD / UCD from the BS1 110 before the handover, and stores the base station identifier BS ID, DCD / UCD value, etc. as current base station information in the memory. When the handover to the BS2 120 is completed, the terminal 100 receives the DCD / UCD from the newly connected BS2 120 and receives the DCD / UCD value received from the BS2 120 together with the BS ID of the BS2 120. Etc. are stored in the memory as the current base station information, and the previous BS1 110 information (BS ID, DCD / UCD value, etc.) is stored in the memory as the previous base station information for a predetermined time.

BS1 (110) is a base station that provides a service to the terminal 100 by managing the cell to which the terminal 100 belongs before handover, which is referred to as a 'serving BS'. There may be a plurality of neighboring base stations around BS1 110. A BS2 120 newly connected to a terminal disconnected from the BS1 110 through a handover or a network access procedure among a plurality of neighboring base stations and providing a service is called a target BS. Here, the target base station includes not only homogeneous systems but also base stations of heterogeneous systems.

BS1 110 periodically transmits neighbor BS Information to UE 100 through a Mobile Neighbor Advertisement Message (MOB_NBR-ADV Message), whereby UE 100 becomes a target BS. It has the information of neighboring base stations in advance. That is, when the terminal 100 moves to an adjacent cell, the terminal 100 transmits the BS2 120 of the target base station such as network ID and channel characteristics by the MOB_NBR-ADV message broadcast from the BS1 110 serving base station. You have the information beforehand.

 The ASN-GW 130 sends a Neighbor_BS_Resource_Status_Update message to the base stations to update the base station information in the neighbor base station list that the base stations have. That is, the terminals connected to the serving base station BS1 110 transmit a list (NBL) and resource status information (DCD / UCD, etc.) of neighboring base stations capable of handover to the BS1 110 serving as the serving base station.

The core network 140 is a part associated with the ASN-GW 130 and the heterogeneous network 150, and a description thereof will be omitted since the description is outside the scope of the present invention.

2 is a flowchart illustrating a process of updating neighboring base station information according to an embodiment of the present invention.

Referring to FIG. 2, when the terminal completes a handover or network entry procedure from BS1 to BS2 (S200), the terminal stores the information of BS1 as memory of the previous base station (S210).

BS2 transmits a previous BS information request message (PreBSInfo-REQ message) to the UE which has completed the handover or network entry procedure (S220), and collects information necessary for updating neighbor BS information which BS2 already has. That is, the terminal requests the base station detailed information of the BS1 that was connected before handover or network entry.

Here, the form of the neighbor base station information request message (PreBSInfo-REQ message) is shown in Table 1. That is, the PreBSInfo-REQ message includes management message type and message size information, and information other than the above information may be added.

Name Size (bit) Descriptions Management Message Type 8

On the other hand, when the terminal receives the PreBSInfo-REQ message from the BS2, and transmits the previous base station information stored in the memory to the BS2 through the previous base station information response message (PreBSInfo-RSP message) (S230). The form of the neighbor base station information response message (PreBSInfo_RSP) is shown in Table 2.

Name Size (bit) Descriptions Management Message Type 8 Response 8 0x00: OK 0x01: NULL value caused by Timer (Ta) expiration 0x02: NULL value caused by initialization 0x03 ~ 0xff: reserved TLV Encoded BS Information TLV Specific System type 8 ex) WiMAX, WiFi, LTE, UMTS, cdma2000, etc. System information var Vendor-specific System Information var BS Info > BS ID 48 Previous BS ID > DCD Configuration Change Count 8 > UCD Configuration Change Count 8 > DCD Settings var The DCD_settings is a compound TLV that encapsulates TLVs from the previous BS 'DCD message that may be transmitted in the advertised BS downlink channel. > UCD Settings var The UCD_settings is compound TLVs that encapsulates TLVs from the previous 　 BS ' 　 UCD message that may be transmitted in the advertised BS downlink channel.

Here, 'Response' has a size of 8 bits and indicates the presence or absence of information of the previous base station stored in the terminal. That is, 0x00 in the 8-bit information indicates that the previous base station information is effectively stored as "OK", 0x01 indicates that the previous base station information has a "Null" value since Ta, which is the valid time of the previous base station information storage, and 0x02. Indicates that the previous base station information has a "Null" value by initialization, and 0x03 to 0xff indicate a state in which it is reserved to accommodate other data. As such, when the 'Response' value included in the PreBSInfo_RSP message is confirmed, it is possible to confirm the existence of the previous base station information stored in the terminal.

The PreBSInfo_RSP message includes encoded BS information as previous base station information. Specifically, the BS information includes a BS ID, which is a previous base station identifier having a size of 48 bits, a configuration change count (CCC) value of 8 bits of DCD, a UCD CCC value of 8 bits, a DCD setting of 8 bits, and 8 Contains the UCD Settings of the bit. The DCD setting is a combined TLV value that encapsulates the TLV from the DCD message of the previous BS that can be transmitted on the BS downlink channel, and the UCD setting encapsulates the TLV from the UCD message of the previous BS that can be transmitted on the BS uplink channel. One combination is the TLV value.

In addition, the adjacent base station information management system according to an embodiment of the present invention can be configured to work with heterogeneous systems such as WiFi, LTE, as well as WiMAX. As described in FIG. 1, the core network 140 may be connected to the heterogeneous network 150 to perform handover with a base station existing in the heterogeneous network, or perform network entry. Therefore, to support this, the PreBSInfo_RSP message may further include system information having a variable length as basic information required for handover between heterogeneous networks, for example, WiMAX, WiFi, LTE, UMTS, CDMA 2000, and the like. Can be. In addition, the PreBSInfo_RSP message may further include base station specific system information having a variable length in order to support interworking between base stations provided by different vendors in the same system.

Meanwhile, the BS2 determines whether to update the neighboring base station information held in advance by using the PreBSInfo-RSP message received from the terminal (S240). Here, the target to be updated is different between the handover and network entry. That is, in the case of handover, the information in the neighboring base station list is updated, while in the case of network entry, the information in the neighboring base station list itself and the neighboring base station list are updated. A method of determining whether to update the neighboring base station information will be described with reference to FIG. 3.

3 is a flowchart illustrating a process of processing previous base station information included in a PreBSInfo-RSP message to determine whether to update neighboring base station information by using a terminal that has completed a network entry procedure.

Referring to FIG. 3, BS2 first checks the "Response" field of the PreBSInfo_RSP message (S300). If the value of the 'Response' field is "Null", since the previous BS information is not included in the PreBSInfo_RSP message, the BS2 terminates the procedure of updating the neighboring base station information.

If the check result 'Response' field value is "OK", the BS2 checks the BS ID which is the previous base station identifier included in the PreBSInfo_RSP message (S310). Thereafter, the BS2 checks the BS ID, and as a result, BS2 checks whether the BS ID is included in the neighbor BS list received from the ASN GW in advance (S320).

If it is determined that the BS ID is included in the neighbor base station list, the BS2 determines whether the CCC values of the DCD and the UCD are valid values (S340). If the CCC value is valid, the previous base station information is determined to be valid, and the neighbor base station information of BS2 is updated.

In contrast, if it is determined that the BS ID is not included in the neighbor base station list, the BS2 performs a process of updating the neighbor base station list (S330). In this case, the BS2 may optionally perform the base station information update process shown in FIG. 4 after updating the neighbor base station list.

Since BS2 has already received neighboring base station information from the terminal through PreBSInfo_RSP, the neighboring base station list updating process may be performed by itself. However, in this case, it is impossible to update the neighbor base station list of all base stations through the ASN-GW, so it is impossible to update the neighbor base station list throughout the system. Accordingly, BS2 may request the base station information update from BS1, which is the base station to be updated through ASN-GW. In this case, ASN-GW also receives base station information of BS1. You can also update it.

In addition to the above embodiment, when the response value in the PreBSInfo_RSP message is 'OK', the method may further include checking a system field. As a result of checking system field, in case of system other than WiMAX, 'System Information' and 'Vendor-specific System Information' are saved and finished. This may occur when heterogeneous systems coexist in addition to WiMAX, or when base stations are provided by different operators even in the case of homogeneous systems, and the step of checking the system field may be excluded.

Meanwhile, in the case of the terminal that has completed the handover procedure, since the neighbor base station list is updated through the handover process, only the neighbor base station information in the neighbor base station list is updated. The remaining steps apply equally.

4 is a diagram illustrating a process of updating base station information between BSs through an ASN-GW according to a preferred embodiment of the present invention.

Referring to FIG. 4, if it is determined that an update of the neighbor base station list that the base station already has is necessary, the ASN-GW receives information necessary for updating from the neighbor base station.

The requesting BS 110 transmits an RRM Radio_Config_Update_Req message requesting an update of the neighbor base station list to the ASN-GW 130 (S400).

The ASN-GW 130 transmits the RRM Radio_Config_Update_Req received from the Requesting BS 110 to the Reporting BS 120 to request information necessary for updating the neighboring base station list (S410).

Upon receiving the Radio_Config_Update_Req message, the Reporting BS 120 creates a Radio_Config_Update_Rpt message including information required for updating the neighboring base station list and transmits the message to the ASN-GW 130 (S420).

The ASN-GW 130 transmits the Radio_Config_Update_Rpt message to the Requesting BS 110 to transmit information necessary for the update to the Requesting BS 110 (S430). That is, by transmitting the Radio_Config_Update_Rpt message, neighboring base station information of the requesting BS 110 is updated.

When the Radio_Config_Update_Rpt message is normally received, the Requesting BS 110 transmits an ACK message for the Radio_Config_Update_Rpt message to the Reporting BS 120 through the ASN-GW 130 (S440 and S450).

5 is a block diagram illustrating a terminal for managing a neighbor list in a mobile communication system according to an embodiment of the present invention.

Referring to FIG. 5, the terminal includes an RF processor 500, 516, an ADC 502, an OFDM demodulator 504, a decoder 506, a controller 508, an encoder 510, an OFDM modulator 512, and a DAC. 514, a memory 518, and a previous base station information generation unit 520. The receiving RF processor 500 and the transmitting RF processor 510 may operate in a frequency division duplex (FDD) or a time division duplex (TDD) mode.

During the reception period, the RF processor 500 converts a radio frequency (RF) signal received through an antenna into a baseband analog signal. The ADC 502 converts an analog signal from the RF processor 500 into sample data and outputs the sample data. The OFDM demodulator 504 converts the sample data output from the ADC 502 into data of a frequency domain by fast Fourier transform (FFT), and selects and outputs data of subcarriers to be actually received from the data of the frequency domain. . The decoder 506 demodulates and decodes the data from the OFDM demodulator 504 according to a predetermined modulation level (MCS level).

The control unit 508 controls the overall operation of the terminal, and performs a network entry procedure with a neighboring base station after disconnection from the base station. When the neighbor base station is connected, the controller 508 receives the previous base station information stored in the memory 518 and transmits a PreBSInfo_RSP message to the base station that has transmitted the PreBSInfo_REQ message. The controller 508 maintains the current serving base station information in the memory while continuously downloading the DCD / UCD from the current serving base station. If the terminal does not receive the DCD / UCD from the base station, the controller 508 considers that the connection with the base station is disconnected and moves the current neighboring base station information to the previous base station information.

Thereafter, the controller 508 stores the neighbor base station information stored as the previous base station information in the buffer of the terminal for Ta time and is deleted when the Ta time elapses.

If the previous base station information generation unit 520 determines that the handover procedure is completed or the network is disconnected, the base station information generation unit 520 may determine that the base station before the handover entry or the network disconnection provided the service to the terminal under the control of the controller 508. Generates previous base station information including base station identifier (BS ID), DCD setting, UCD setting, CCD of DCD, CCC of UCD, system type, system information, operator specific system information, and transmits it to memory 518 .

The encoder 510 codes and modulates the data from the controller 508 according to a predetermined modulation level (MCS level) and outputs the data. The OFDM modulator 512 outputs sample data (OFDM symbols) by performing IFFT (Inverse Fast Fourier Transform) on the data from the encoder 510. The DAC 514 converts the sample data into an analog signal and outputs the analog signal. The RF processor 516 converts an analog signal from the DAC 514 into a radio frequency (RF) signal and transmits the same through an antenna.

In the above configuration, the control unit 508 is a protocol control unit, and controls the previous base station information generation unit 520. That is, the controller 508 may perform a function of the previous base station information generation unit 520. In the present invention, it is separately configured to describe each function separately. Therefore, in actual implementation, all of them may be configured to be processed by the controller 508, and only some of them may be configured to be processed by the controller 508. In addition, the controller 508 receives the necessary information during the protocol processing to the corresponding component of the physical layer, or generates a control signal to the corresponding component of the physical layer.

6 is a block diagram illustrating a base station for updating a neighbor list in a mobile communication system according to an embodiment of the present invention.

 Referring to FIG. 6, the base station includes an RF processor 600, 616, an ADC 602, an OFDM demodulator 604, a decoder 606, a controller 608, an encoder 610, an OFDM modulator 612, and a DAC. 614, the interface unit 620, and the neighboring base station information management unit 618. Here, the functions of the RF processors 600 and 616, the ADC 602, the OFDM demodulator 604, the decoder 606, the encoder 610, the OFDM modulator 612, and the DAC 614 are the functions of FIG. 5. The same description as in FIG. 5 will refer to FIG. 5.

The controller 608 controls the overall operation of the base station, performs a network entry procedure with a corresponding terminal disconnected from the previous base station, allocates bandwidth to the corresponding terminal, and receives log information.

The neighbor base station information management unit 618 uses the log information from the control unit 608 to determine whether an update of the neighbor base station list / information is necessary.

The neighbor base station information management unit 618 checks the response field in the PreBSInfo_RSP message received from the terminal. If the response value is 'Null', since the terminal does not have previous base station information, the neighbor base station information update procedure ends. This occurs when the terminal establishes an initial connection, or when the Ta time set in the buffer in the terminal passes, or reconnects due to a handover failure or a signal search failure.

If the value of 'Response' is 'Null', the neighboring base station information management unit 618 checks the BS ID in the PreBSInfo_RSP message. If the BS ID is included in the neighbor BS list of the BS, the BS checks the configuration change count (CCC) value of the DCD / UCD since the BS has already received information about the BS. If the CCC value of the DCD / UCD is a valid value, the base station updates the neighboring base station information. If the CCC value of the DCD / UCD is not a valid value, the update process is terminated.

If, as a result of checking the BS ID, if the BS ID is not included in the neighboring base station list of the base station, the base station performs a procedure for reporting BS-to-BS radio configuration update (Per-BS Radio Configuration Update Reporting). Precedure) can be performed.

Since the base station already has neighboring base station information received from the terminal, the procedure can be selectively performed.

When the neighbor list update is required, the interface unit 620 updates the neighbor list and transmits updated neighbor list information to the previous base station.

In the above configuration, the control unit 608 is a protocol control unit, and controls the neighbor base station information management unit 618. That is, the controller 608 may perform a function of the neighbor base station information management unit 618. In the present invention, it is separately configured to describe each function separately. Therefore, in actual implementation, all of them may be configured to be processed by the controller 608, and only some of them may be configured to be processed by the controller 608. In addition, the controller 608 receives the necessary information during the protocol processing to the corresponding component of the physical layer or generates a control signal to the corresponding component of the physical layer.

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

1 is a diagram illustrating a system for supporting handover according to the related art.

2 is a flowchart illustrating a process of updating neighboring base station information according to an embodiment of the present invention.

3 is a flowchart illustrating a previous base station information processing procedure received from a terminal according to an embodiment of the present invention.

4 is a diagram illustrating a radio configuration update process between BSs according to an embodiment of the present invention.

5 is a block diagram showing the configuration of a terminal device according to an embodiment of the present invention.

6 is a block diagram showing the configuration of a base station apparatus according to an embodiment of the present invention.

Claims (12)

A method of managing neighbor base station information using a terminal that performs connection establishment and handover in a broadband wireless communication system, Transmitting a message requesting information about a previous base station that was connected before handover to a terminal having completed the handover or network entry procedure; Determining whether to update neighboring base station information by using a previous base station information response message received from the terminal; And performing the neighbor base station information update if the neighbor base station information update is necessary as a result of the determination. The method of claim 1, Determining whether the neighboring base station information is updated, Determining whether the previous base station information response message includes previous base station information; When the response message includes previous base station information, determining whether the previous base station information is included in a previously stored neighbor base station list; And determining that the neighbor base station information is required to be updated if the previous base station information is not included in the neighbor base station list. The method of claim 2, The neighboring base station information update step, Requesting neighbor base station information to be updated to an access service network (ASN) -GateWay; Receiving the requested neighbor base station information through the ASN-GW; And updating neighboring base station information by using the received neighbor base station information. The method of claim 3, wherein The neighbor base station information request is made through a Radio_Config_Update_Req message, neighbor base station information management method. A terminal for managing neighbor base station information in a broadband wireless communication system, A storage unit for storing the base station information of the first base station as the previous base station information when the connection with the first base station is lost; The controller performs a handover procedure with the second base station after disconnection with the first base station, and transmits the previous base station information as a previous base station information response message when the previous base station information request message is received from the second base station after the handover is completed. Including, the terminal. The method of claim 5, The storage unit, characterized in that for storing the previous base station information for a predetermined time, and after a predetermined time elapsed, the terminal. The method of claim 5, The storage unit, characterized in that for storing the current base station information as the previous base station information after a predetermined time. The method of claim 5, The previous base station information response message, including the previous base station information, the base station identifier (BS ID), the terminal. A terminal for storing previously connected base station information as a previous base station information for a predetermined time when the network connection is lost; And A neighbor base station information management system including a base station transmitting a previous base station information request message to a terminal that has completed a network entry or handover procedure, and determining whether to update neighboring base station information from previous base station information received from the terminal and performing the update. . The method of claim 9, When the neighbor base station information update request message is received from the base station, ASN-GW for requesting information from the neighboring base station to transmit the update information to the base station, further comprising: The base station transmits a neighbor base station information update request message to the ASN-GW if it is determined that the base station information needs to be updated based on the neighbor base station information received from the terminal. . The method of claim 9, The terminal stores the previous base station information for a predetermined time, characterized in that for deleting, neighboring base station information management system. The method of claim 9, The previous base station information includes the previous base station information, the base station identifier (BS ID), neighboring base station information management system.

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