WO2014163419A1 - Method for processing radio link failure and device therefor - Google Patents

Abstract

The present invention relates to a method by which a terminal processes a radio link failure (RLF) by detecting the same and, specifically, a method and an apparatus for processing an RLF if the terminal detects the occurrence of the RLF of a cell associated with a specific base station especially when a terminal accesses at least two cells from different base stations. The method by which a terminal processes a RLF comprises the steps of: configuring a dual connection of at least one cell associated with a first base station and at least one cell associated with a second base station; detecting the occurrence of a RLF of at least one cell from the at least one cell associated with the first base station and/or the at least one cell associated with the second base station; transmitting a signal related to the RLF to the first base station or second base station; and receiving setting information for processing the RLF.

Description

Radio link failure processing method and device

The present invention relates to a method in which a terminal detects and processes a radio link failure (RFL). In particular, when a terminal accesses at least two or more cells of different base stations, a radio link failure in a cell associated with a specific base station The present invention relates to a method and apparatus for processing the same when the occurrence is detected.

As communication systems have evolved, consumers, such as businesses and individuals, have used a wide variety of wireless terminals.

Currently, mobile communication systems such as Long Term Evolution (LTE) and LTE-Advanced of the 3GPP series require high-speed large-capacity communication systems capable of transmitting and receiving various data such as video and wireless data, beyond voice-oriented services.

Data processing technology using a plurality of cells has been studied for such a high-speed large-capacity communication system.

In addition, the radio link failure (RFF) is detected when the terminal has a problem in communication with the base station. When the radio link failure occurs, the terminal performs a processing procedure for resuming communication with the base station.

Therefore, in an environment in which the terminal communicates with a plurality of cells provided by a plurality of different base stations, when a radio link failure occurs in some cells of the plurality of cells, the terminal detects a cell where the radio link failure occurs, and the radio link failure There is a need for a specific processing method for resuming communication with a plurality of cells by restoring a generated cell.

According to the above-described demands, there is a need for detecting a radio link failure occurrence for each of a cell associated with a first base station and a cell associated with a second base station in an environment in which a terminal forms a dual connection with at least two base stations.

In addition, if a radio link failure is detected, there is a need to quickly recover the radio link failure according to a base station associated with a cell in which the radio link failure has occurred.

In addition, when a radio link failure occurs in a cell associated with any one base station in a dual connectivity environment, data processing through another base station is possible, and thus a radio link failure recovery method is required.

In order to solve the above problems, the present invention provides a terminal for processing a radio link failure (Radio Link Failure, RLF), at least one cell associated with the first base station and at least one cell associated with the second base station Configuring a dual connection, detecting at least one radio link failure occurrence for at least one cell of at least one cell associated with the first base station and at least one cell associated with the second base station and a first base station or a second base station The present invention provides a method comprising transmitting a radio link failure related signal and receiving configuration information for radio link failure processing.

In addition, the present invention provides a method for controlling a radio link failure (RLF) processing of the terminal by the first base station, receiving a radio link failure-related signal from the terminal or a second base station providing additional radio resources to the terminal And generating setting information for radio link failure processing and transmitting setting information for radio link failure processing.

The present invention also provides a method for controlling a radio link failure (RLF) processing of a terminal by a second base station, comprising: configuring a dual connection to a terminal together with a first base station providing a radio resource to the terminal; Receiving a radio link failure related signal including information indicating any one of information indicating a radio link failure of a cell associated with a first base station and information on pending indication of a cell associated with a second base station from a terminal or a first base station; It provides a method to include.

In addition, the present invention provides a terminal for processing a radio link failure (Ralf Link Failure, RLF), comprising: a control unit for configuring a dual connection with at least one cell associated with the first base station and at least one cell associated with the second base station; Transmitting a radio link failure related signal to a control unit for detecting a radio link failure occurrence for at least one or more cells of at least one cell associated with the first base station and at least one cell associated with the second base station and the first base station or the second base station. Provided is a terminal apparatus including a transmitter and a receiver configured to receive configuration information for radio link failure processing.

In addition, the present invention is a first base station for controlling the radio link failure (RLF) processing of the terminal, the receiving unit for receiving a radio link failure-related signal from the terminal or a second base station providing additional radio resources to the terminal And a control unit for generating configuration information for radio link failure processing and a transmitter for transmitting configuration information for radio link failure processing.

In addition, the present invention provides a second base station for controlling the radio link failure (RLF) processing of the terminal, the control unit and the terminal for configuring a dual connection with the first base station providing a radio resource to the terminal or And a receiver configured to receive a radio link failure related signal including information indicating any one of radio link failure occurrences of a cell associated with a first base station and information indicating a pending indication of a cell associated with a second base station from a first base station. Provides a base station apparatus.

As described above, according to the present invention, there is an effect of detecting the occurrence of radio link failure for each cell associated with the first base station and the cell associated with the second base station in an environment in which the terminal forms a dual connection with at least two base stations. .

In addition, if a radio link failure is detected, there is an effect of quickly recovering the radio link failure according to the base station associated with the cell where the radio link failure has occurred.

In addition, when a radio link failure occurs in a cell associated with any one base station in a dual connectivity environment, since data processing is possible through another base station, there is an effect of providing a method and apparatus for recovering a radio link failure considering this.

1 is a diagram illustrating an embodiment in which a terminal to which the present invention can be applied performs communication by forming a dual connection with a plurality of different base stations.

2 is a diagram exemplarily illustrating operations of a terminal and a base station when radio link failure occurs in a cell associated with a second base station according to an embodiment of the present invention.

3 is a diagram illustrating an example of a message that may be included in a radio link failure related signal according to another embodiment of the present invention.

4 is a diagram illustrating another example of a message that may be included in a radio link failure related signal according to another embodiment of the present invention.

5 is a diagram illustrating an example of setting information according to another embodiment of the present invention.

6 is a diagram illustrating an example of operations of a terminal and a base station when a radio link failure occurs in a cell associated with a first base station according to another embodiment of the present invention.

FIG. 7 is a diagram illustrating an example of a message that may be included in a radio link failure related signal that may be included in a radio link failure related signal according to another embodiment of the present invention.

8 is a diagram illustrating an example of a message that may be included in configuration information according to another embodiment of the present invention.

FIG. 9 is a diagram illustrating another example of operations of a terminal and a base station when radio link failure occurs in a cell associated with a first base station according to another embodiment of the present invention.

FIG. 10 is a diagram illustrating another example of operations of a terminal and a base station when radio link failure occurs in a cell associated with a first base station according to another embodiment of the present invention.

11 is a diagram illustrating an example of an operation of a terminal according to an order of detecting radio link failure in a cell associated with a first base station and a second base station according to another embodiment of the present invention.

12 is a diagram illustrating another example of a processing operation according to an order in which a radio link failure is detected in a cell associated with a first base station and a second base station by a terminal according to another embodiment of the present invention.

13 is a flowchart illustrating the operation of a terminal according to another embodiment of the present invention.

14 is a flowchart illustrating the operation of a first base station according to another embodiment of the present invention.

15 is a flowchart illustrating the operation of a second base station according to another embodiment of the present invention.

16 is a diagram illustrating a configuration of a terminal according to another embodiment of the present invention.

17 is a diagram illustrating the configuration of a first base station and a second base station according to another embodiment of the present invention.

Hereinafter, some embodiments of the present invention will be described in detail through exemplary drawings. In adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are assigned to the same components as much as possible even though they are shown in different drawings. In addition, in describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

The wireless communication system in the present invention is widely deployed to provide various communication services such as voice, packet data, and the like. The wireless communication system includes a user equipment (UE) and a base station (base station, BS, or eNB). In the present specification, a user terminal is a comprehensive concept of a terminal in wireless communication. In addition to user equipment (UE) in WCDMA, LTE, and HSPA, as well as MS (Mobile Station), UT (User Terminal), SS in GSM, It should be interpreted as a concept that includes a subscriber station, a wireless device, and the like.

Hereinafter, in the present specification, a user terminal may be referred to as a terminal for short.

A base station or a cell generally refers to a station that communicates with a user terminal, and includes a Node-B, an evolved Node-B, an Sector, a Site, and a BTS. It may be called other terms such as a base transceiver system, an access point, a relay node, a remote radio head (RRH), a radio unit (RU), and the like.

In other words, in the present specification, a base station or a cell is a generic meaning indicating some areas or functions covered by a base station controller (BSC) in CDMA, a Node-B in WCDMA, an eNB or a sector (site) in LTE, and the like. It should be interpreted as, and it is meant to cover all the various coverage areas such as megacell, macrocell, microcell, picocell, femtocell and relay node, RRH, RU communication range.

Since the various cells listed above have a base station for controlling each cell, the base station may be interpreted in two senses. i) the device providing the megacell, the macrocell, the microcell, the picocell, the femtocell, the small cell in relation to the wireless area, or ii) the wireless area itself. In i) all devices which provide a given wireless area are controlled by the same entity or interact with each other to cooperatively configure the wireless area to direct the base station. The eNB, RRH, antenna, RU, LPN, point, transmit / receive point, transmit point, receive point, etc. become embodiments of the base station according to the configuration of the radio region. In ii), the base station may indicate the radio area itself to receive or transmit a signal from a viewpoint of a user terminal or a neighboring base station.

Therefore, megacells, macrocells, microcells, picocells, femtocells, small cells, RRHs, antennas, RUs, low power nodes (LPNs), points, eNBs, transmit / receive points, transmit points, and receive points are collectively referred to as base stations. do.

In the present specification, the user terminal and the base station are two transmitting and receiving entities used to implement the technology or technical idea described in this specification in a comprehensive sense and are not limited by the terms or words specifically referred to. The user terminal and the base station are two types of uplink or downlink transmitting / receiving subjects used to implement the technology or the technical idea described in the present invention, and are used in a generic sense and are not limited by the terms or words specifically referred to. Here, the uplink (Uplink, UL, or uplink) refers to a method for transmitting and receiving data to the base station by the user terminal, the downlink (Downlink, DL, or downlink) means to transmit and receive data to the user terminal by the base station It means the way.

There is no limitation on the multiple access scheme applied to the wireless communication system. Various multiple access techniques such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), OFDM-FDMA, OFDM-TDMA, OFDM-CDMA Can be used. One embodiment of the present invention can be applied to resource allocation in the fields of asynchronous wireless communication evolving to LTE and LTE-Advanced through GSM, WCDMA, HSPA, and synchronous wireless communication evolving to CDMA, CDMA-2000 and UMB. The present invention should not be construed as being limited or limited to a specific wireless communication field, but should be construed as including all technical fields to which the spirit of the present invention can be applied.

The uplink transmission and the downlink transmission may use a time division duplex (TDD) scheme that is transmitted using different times, or may use a frequency division duplex (FDD) scheme that is transmitted using different frequencies.

In addition, in systems such as LTE and LTE-Advanced, a standard is configured by configuring uplink and downlink based on one carrier or a pair of carriers. Uplink and downlink transmit control information through control channels such as Physical Downlink Control CHannel (PDCCH), Physical Control Format Indicator CHannel (PCFICH), Physical Hybrid ARQ Indicator CHannel (PHICH), and Physical Uplink Control CHannel (PUCCH). A data channel is configured such as PDSCH (Physical Downlink Shared CHannel), PUSCH (Physical Uplink Shared CHannel) and the like to transmit data.

On the other hand, control information can also be transmitted using an enhanced PDCCH (EPDCCH or extended PDCCH).

In the present specification, a cell means a component carrier having a coverage of a signal transmitted from a transmission / reception point or a signal transmitted from a transmission point or a transmission / reception point, and the transmission / reception point itself. Can be.

A wireless communication system to which embodiments are applied may be a coordinated multi-point transmission / reception system (CoMP system) or a coordinated multi-antenna transmission scheme in which two or more transmission / reception points cooperate to transmit a signal. antenna transmission system), a cooperative multi-cell communication system. The CoMP system may include at least two multiple transmission / reception points and terminals.

In one embodiment of the base station, the multiple transmit / receive point may be at least one RRH having a high transmit power or low transmit power in the macro cell region, which is wired controlled by an optical cable or fiber optic to the base station or macro cell and the eNB. have.

In the following, downlink refers to a communication or communication path from a multiple transmission / reception point to a terminal, and uplink refers to a communication or communication path from a terminal to multiple transmission / reception points. In downlink, a transmitter may be part of multiple transmission / reception points, and a receiver may be part of a terminal. In uplink, a transmitter may be part of a terminal, and a receiver may be part of multiple transmission / reception points.

Hereinafter, a situation in which a signal is transmitted and received through a channel such as a PUCCH, a PUSCH, a PDCCH, an EPDCCH, and a PDSCH may be expressed in the form of 'sending and receiving a PUCCH, a PUSCH, a PDCCH, an EPDCCH, and a PDSCH.'

Meanwhile, high layer signaling described below includes an RRC parameter (or an RRC message) including an RRC parameter and transmitting RRC information.

The base station performs downlink transmission to the terminals. The base station includes downlink control information such as a physical downlink shared channel (PDSCH), which is a main physical channel for unicast transmission, and scheduling required for reception of the PDSCH and an uplink data channel (eg, For example, a physical downlink control channel (PDCCH) for transmitting scheduling grant information for transmission on a physical uplink shared channel (PUSCH) may be transmitted. Hereinafter, the transmission and reception of signals through each channel will be described in the form of transmission and reception of the corresponding channel.

Small cell environments using low power nodes are being considered as a means to cope with the explosion of mobile traffic. Low power nodes represent nodes that use lower transmit (Tx) power than typical macro nodes.

In the conventional carrier aggregation (CA) technique, a small cell can be constructed using a low power remote radio head (RRH), which is a geographically dispersed antenna within macro cell coverage.

However, in order to apply CA technology, the macro cell and the RRH cell are constructed to be scheduled under the control of one base station. For this purpose, an ideal backhaul was required between the macro cell node (or base station) and the RRH.

An ideal backhaul means a backhaul that exhibits very high data throughput and very low latency, such as optical fiber, dedicated point-to-point connections using line of sight microwaves.

In contrast, a backhaul that exhibits relatively low data throughput and high latency, such as a digital subscriber line (xDSL) or a non-LOS microwave, is called a non-ideal backhaul.

Through the above-described CA technology, a plurality of serving cells may be merged to provide a service to a user equipment. That is, a plurality of serving cells may be configured for a terminal in an RRC (Radio Resource Control) connection state, and when an ideal backhaul is established between the macro cell node and the RRH, the macro cell and the RRH cell are configured together with the serving cells. Could provide service to

When such a CA technology is configured, the terminal may have only one RRC connection with the network. In RRC connection establishment / re-establishment / handover, one serving cell provides NAS mobility information (e.g., Tracking Area Identity, TAI), and RRC connection reset / In handover, one serving cell provides a security input. In CA, such a cell is called a PCell (Primary Cell). The PCell can only be changed with the handover procedure.

According to terminal capabilities, SCells (Secondary Cells) may be configured as serving cells together with PCells. Addition and removal of SCells are performed by higher layer signaling (eg, RRC message). When adding a new SCell, dedicated RRC signaling is used for all required system information transmission of the SCell. That is, in the connected mode, the terminal does not need to acquire system information broadcast directly from the SCells.

On the other hand, radio link failure (Radio Link Failure, RLF) means a problem occurs in the connection state between the base station and the terminal providing the serving cell.

Specifically, for example, the terminal may detect the occurrence of a radio link failure in the following cases.

Detect RLF when out-of-synchronization occurs in the physical layer.

Detects the occurrence of RLF when a random access problem occurs in the MAC layer.

Detects the occurrence of RLF when the maximum number of retransmissions is reached in the RLC layer.

In the three cases described as examples above, the UE may detect the occurrence of the RLF.

When the UE detects the RLF, if the AS (Access Stratum) security (activation) is activated (activation), the RRC connection re-establishment (procedure) procedure. If the AS security is not activated, the terminal immediately falls to the idle state (IDLE).

Conventionally, a terminal connected to a plurality of cells as in the aforementioned CA detects the RLF for the PCell, but does not detect the RLF for the SCell. When the UE detects the RLF with respect to the PCell, the terminal performs an RRC connection reestablishment procedure. At this time, the terminal releases the SCell. Thereafter, the UE may newly use the SCell after configuring the SCell addition through the RRC connection reconfiguration procedure.

When the UE detects the RLF, the RLF related information as shown in Table 1 below may be stored in the VarRLF-Report.

Table 1

The UE, which has stored the aforementioned RLF-related information, performs a RRCConnectionReestablishmentComplete / RRCConnectionReconfigurationComplete / RRCConnectionSetupComplete message when the RRC connection reestablishment / RRC connection reconfiguration / RRC connection establishment procedure is performed later. Set rlf-InfoAvailable to true and transmit it to the base station.

Upon receiving the above-mentioned message, the base station sets rlf-ReportReq to true in the UE Information Request message and transmits it to the UE in order to obtain an RLF report. Upon receiving the terminal information request message, the terminal transmits the rlf-report to the base station in the UE information response message.

In the carrier aggregation (CA) described above, since the PCell and the SCell belong to the same base station, and the data is not transmitted separately by cell, even if a communication failure occurs in the SCell, data is continuously transmitted and received through the PCell.

However, in the dual connectivity situation to which the present invention is applied, a cell associated with the first base station and a cell associated with the second base station belong to different base stations, and a radio bearer may be configured independently for each cell.

Therefore, in this case, when a communication failure occurs in a cell associated with the second base station, data through a radio bearer configured through the cell associated with the second base station cannot be transmitted.

On the contrary, if the RLF is generated in the cell associated with the first base station, conventionally, the terminal releases all SCells connected to the terminal and starts an RRC connection reestablishment procedure.

That is, unlike the conventional method, in the dual connectivity environment, since the cell associated with the first base station and the cell associated with the second base station are provided from different base stations, the cell associated with the first base station is associated with the second base station even if an RLF has occurred. The cell can send and receive data without problems. In this case, if all cells are released as in the related art, there is a problem that an inefficient and unnecessary reset operation may be performed.

Therefore, in the following, when a radio link failure occurs in a cell associated with at least one or more base stations among a plurality of base stations in a dual connectivity environment, a method of efficiently recovering without performing an unnecessary reset operation according to each embodiment is specifically described. Explain.

Dual connectivity in the present specification may mean that the terminal communicates with a plurality of base stations connected by non-ideal backhaul. That is, the terminal may configure a dual connection with a base station providing a macro cell and a base station providing a small cell or a dual connection with a plurality of base stations providing a small cell.

In this case, the terminal may transmit and receive data with a plurality of base stations, and configure a radio bearer with the plurality of base stations. For example, a plurality of radio bearers may be configured in each of the plurality of base stations, or one radio bearer may be split and configured through the plurality of base stations.

In the present specification, when the terminal configures dual connectivity, forms an RRC connection with the terminal, terminates the base station or S1-MME providing a PCell that is the basis of handover, and serves as a mobility anchor for the core network. A base station to be described as a master base station or a first base station.

The master base station or the first base station may be a base station providing a macro cell, and may be a base station providing any one small cell in a dual connectivity situation between the small cells.

Meanwhile, a base station that is distinguished from a master base station in a dual connectivity environment and provides additional radio resources to a terminal is described as a secondary base station or a second base station.

The first base station (master base station) and the second base station (secondary base station) may each provide at least one cell to the terminal. The first base station and the second base station may be connected through an interface between the first base station and the second base station.

In addition, a cell associated with the first base station may be referred to as a macro cell, and a cell associated with the second base station may be referred to as a small cell for clarity. However, in a small cell cluster scenario in which a dual connectivity with a plurality of base stations providing a small cell is present, a cell associated with the first base station may also be described as a small cell.

In the present invention, the macro cell may mean each of at least one or more cells, and may be described as representing a whole cell associated with the first base station. In addition, the small cell may also mean each of at least one or more cells, and may also be described as representing a whole cell associated with the second base station. However, as described above, in a specific scenario such as a small cell cluster, the cell may be a cell associated with the first base station. In this case, the cell of the second base station may be described as another small cell or another small cell.

1 is a diagram illustrating an embodiment in which a terminal to which the present invention can be applied performs communication by forming a dual connection with a plurality of different base stations.

Referring to FIG. 1, the terminal 122 may configure a dual connection with the first base station 110 and the second base station 120. The terminal 122 configuring the dual connection may transmit and receive information through a radio link of each of the first base station 110 and the second base station 120.

The other terminal 112 may transmit and receive information only with the first base station 110, and the other terminal 124 may transmit and receive information only with the second base station 120.

In this case, the terminal 122 may transmit and receive information with at least one cell associated with the first base station 110 and at least one cell associated with the second base station 120.

Hereinafter, a recovery / processing method in a case where radio link failure occurs in at least one of a cell associated with a first base station and a cell associated with a second base station in a terminal 122 having dual connectivity will be described in detail. do.

In a method for handling a radio link failure (RFF) by a terminal according to an embodiment of the present invention, at least one cell associated with a first base station and at least one cell associated with a second base station may be dually connected. Configuring and detecting occurrence of radio link failure for at least one or more cells of at least one cell associated with the first base station and at least one or more cells associated with the second base station and a radio link to the first base station or the second base station. A method comprising transmitting a failure related signal and receiving configuration information for radio link failure processing is provided.

Specifically, the terminal detects a radio link failure even for a cell associated with the second base station independently of a cell associated with the existing first base station. If a radio link failure occurs in a cell associated with the second base station, the terminal may transmit a signal including information indicating the radio link failure occurrence of the cell associated with the second base station to the first base station.

Or, if a radio link failure occurs in a cell associated with the first base station, the terminal does not release the cell associated with the second base station, and if the terminal is reconnected with the first base station, the cell associated with the second base station described above with the first base station By transmitting information about the terminal, the terminal can continue to use the cell associated with the second base station before detecting the occurrence of the radio link failure.

Alternatively, when a radio link failure occurs in a cell associated with the first base station, the terminal may change the second base station to the master base station by transmitting corresponding information to the second base station. That is, the second base station can be configured to change the role of the above-described master base station.

When the terminal independently detects the occurrence of radio link failure of the cell associated with the first base station and the cell associated with the second base station according to an embodiment of the present invention, the case shown in Table 2 may be considered.

TABLE 2

Hereinafter, the present invention will be described by dividing each embodiment according to each case described in Table 2. When the cell associated with the first base station and the cell associated with the second base station are each a plurality of cells, the present invention described below may be applied when radio link failure occurs in all cells associated with each base station. Alternatively, the present invention described below may be applied when radio link failure occurs in any one of a plurality of cells associated with each base station. In the following description, a case where radio link failure occurs in a cell associated with a first base station or a cell associated with a second base station for convenience of understanding, it should be understood to include all the cases described above.

In addition, the following describes three embodiments of the occurrence of a radio link failure, but the radio link failure is not limited to the three embodiments, all cases where a problem that the terminal and the base station can not perform communication It may include.

In addition, the present invention may be applied only when a radio link failure of a specific cause (for example, reaching the maximum number of retransmissions in the RLC layer) occurs or may be applied regardless of the radio link failure type. In addition, operations of certain embodiments of the present invention may be performed based on the type of radio link failure.

First Embodiment: A Cell Associated with a First Base Station Is Normally Communicating When Radio Link Failure is Detected in a Cell Associated with a Second Base Station

2 is a diagram exemplarily illustrating operations of a terminal and a base station when radio link failure occurs in a cell associated with a second base station according to an embodiment of the present invention.

In a method for handling a radio link failure (RFF) by a terminal according to an embodiment of the present invention, at least one cell associated with a first base station and at least one cell associated with a second base station may be dually connected. Configuring and detecting occurrence of radio link failure for at least one or more cells of at least one cell associated with the first base station and at least one or more cells associated with the second base station and a radio link to the first base station or the second base station. A method comprising transmitting a failure related signal and receiving configuration information for radio link failure processing is provided.

In addition, the terminal according to an embodiment of the present invention, if the cell is detected that the radio link failure is a cell associated with the second base station, the information indicating the radio link failure generation of the cell associated with the second base station to the first base station, wireless A radio link failure related signal including at least one of link failure cause information and index information indicating a cell in which a radio link failure occurs is transmitted.

Referring to FIG. 2, the terminal 201 forms a dual connection with the first base station 202 and the second base station 203 (S210). Dual connectivity can be configured by adding / modifying radio resources of the second base station.

The terminal 201 independently detects a radio link failure occurrence for each cell associated with the first base station and each cell associated with the second base station.

The terminal 201 may not communicate with the second base station 203 when a radio link failure occurs in a cell associated with the second base station.

In this case, the terminal 201 detects a radio link failure occurrence of the cell associated with the second base station (S220).

For example, a radio link failure occurrence of a cell associated with a second base station may occur when out-of-synchronization occurs in a physical layer (a certain number of times) or random access in a MAC layer. ) May be detected when a problem occurs or when the maximum number of retransmissions is reached in the RLC layer.

When the terminal 201 determines that the cell in which the radio link failure has occurred is a cell associated with the second base station, the terminal 201 relates to the radio link failure including information indicating the occurrence of the radio link failure in the cell associated with the second base station to the first base station 202. The signal may be transmitted (S230).

That is, the terminal 201 includes information indicating the radio link failure occurrence of the cell associated with the second base station in the radio link failure related signal when it is determined that the cell in which the radio link failure occurrence is detected is a cell associated with the second base station. It may be transmitted through higher layer signaling (S230).

In addition, the radio link failure related signal may include at least one or more of information indicating radio link failure occurrence of a cell associated with the second base station, radio link failure cause information, and index information indicating a cell where the radio link failure has occurred. Can be. That is, the radio link failure related signal transmitted from the terminal 201 to the first base station 202 includes a specific cell associated with the cause information and / or the second base station where the radio link failure occurred, in addition to the information indicating the occurrence of the radio link failure. Indicative index information may be included. The index information includes information for distinguishing a cell from other cells and may be variously represented as delimiter information, classification information, cell index information, and the like.

In addition, when the radio link failure occurs, the information indicating the occurrence of the radio link failure may be transmitted by the second base station 203 to the first base station 202 (S235). When the second base station reports a radio link failure occurrence to the first base station, it may be delivered through the interface between the first base station and the second base station. Steps S230 and S235 may occur in overlap, and only step S230 or step S235 may be performed.

The first base station 202 and the second base station 203 may exchange necessary information for recovering a cell in which a radio link failure has occurred (S240). Here, the cell selected for recovering the cell where the radio link failure occurs may be a cell associated with the second base station where the radio link failure occurs, or may be another third base station. For convenience of description, a cell associated with the second base station is described, but may be a third base station. In the case of the third base station, steps S240, S265, and S270 may be performed with the third base station.

The first base station 202 transmits the changed configuration information to the terminal 201 to recover a radio link failure (S245).

The terminal 201 may apply the changed setting information (S250) to configure a new radio link (S250).

Thereafter, the first base station 202 transmits an activation request message when the cell associated with the newly configured second base station or the cell associated with the second base station whose radio link failure has been recovered or the cell associated with the third base station is configured (S260). , S265). However, when the newly configured cell or the like is in an activated state, the step of transmitting an activation request message may be omitted.

The terminal 201 may resume / perform communication through the restored or newly configured cell (S270).

3 is a diagram illustrating an example of a message that may be included in a radio link failure related signal according to another embodiment of the present invention.

The radio link failure related signal of the present invention described with reference to FIG. 2 includes at least one of information indicating a radio link failure occurrence, radio link failure cause information, and index information indicating a cell in which a radio link failure has occurred. It can contain one or more pieces of information. The radio link failure related signal may be transmitted through higher layer signaling (eg, RRC signaling).

For example, referring to FIG. 3, a radio link failure related signal may be delivered in an RRC Connection Reestablishment Request message.

In this case, the SeNBFailure element may be added to the ReestablishmentCause to indicate radio link failure of the cell associated with the second base station. It may also include radio link failure cause information.

4 is a diagram illustrating another example of a message that may be included in a radio link failure related signal according to another embodiment of the present invention.

Referring to FIG. 4, index information indicating a cell in which the aforementioned radio link failure occurs may be further included.

The radio link failure related signal may be transmitted in an RRC Connection Reestablishment Request message, and may further include index information indicating a cell in which a radio link failure occurs in addition to the information of FIG. 3.

For example, as shown in FIG. 4, SCellFailure and ServCellIndex elements may be added to transmit radio link failure occurrence of a cell associated with a second base station and index information of a cell associated with the second base station.

Here, SCellFailure may include information indicating the radio link failure generation of the cell associated with the second base station, it may be represented by SeNBFailure of FIG. In addition, ServCellIndex is expressed as an example and may be variously expressed as SeNBCellIndex. Thus, SCell in Figure 4 refers to the cell associated with the second base station.

5 is a diagram illustrating an example of setting information according to another embodiment of the present invention.

After the step of transmitting a radio link failure related signal, the terminal 201 according to an embodiment of the present invention receives configuration information for radio link failure processing from a first base station.

The configuration information according to an embodiment of the present invention includes at least one or more of information for resetting a cell in which a radio link failure occurs and for releasing a cell in which a radio link failure occurs, and changing the radio bearer to a cell associated with the first base station. can do.

The above configuration information may be transmitted through higher layer signaling.

For example, with reference to FIG. 5, configuration information for radio link failure processing for a cell associated with a second base station may be transmitted through a change of SCellToAddMod, radioResourceConfigCommonSCell, and radioResourceConfigDedicatedSCell elements in an existing RRC connection reconfiguration procedure. .

The terminal receives the above-described change information of the SCellToAddMod, radioResourceConfigCommonSCell, and radioResourceConfigDedicatedSCell elements, and based on this, resets a cell associated with the second base station or changes a cell change associated with the second base station by changing cell information associated with the second base station. can do.

According to the above-described configuration information, the cell associated with the second base station to which the terminal 201 resumes communication may be a cell associated with a second base station in which an existing radio link failure has occurred, or a cell associated with a new second base station, It may be a cell associated with a third base station.

In FIG. 5, SCell may mean a cell associated with a second base station, and may be expressed differently such as SeNBCellToAddMod.

Hereinafter, the first embodiment of the present invention will be described once again for each step by taking the example of higher layer signaling described with reference to FIGS. 3 to 5.

1. The terminal performs physical layer monitoring on each of a cell associated with a first base station and a cell associated with a second base station. For example, the terminal may monitor only one representative cell among the cells associated with the second base station, or may monitor the entire cell associated with the second base station.

2. If a synchronization problem (eg, out-of-synchronization) occurs in a physical layer of a cell (represented one cell or all cells described above) associated with a second base station, the terminal may have a problem. Declares a radio link failure for the cell associated with the generated second base station.

For example, the RRC layer of the terminal declares a radio link failure when a predetermined number of out-of-synchronization indications are transmitted from a physical layer. Or, if a random access problem indication is transmitted in the MAC layer, it declares a radio link failure. Or, when the maximum number of retransmissions is reached in the RLC layer, it declares a radio link failure.

3. The terminal transmits a radio link failure related signal including indication information indicating radio link failure of a cell associated with the second base station to the first base station. A radio link failure related signal may be transmitted through higher layer signaling. For example, the indication information may be included in the existing RRC message or a new RRC message for transmitting the indication information may be defined. As another example, the radio link failure related signal of the cell associated with the second base station may be transmitted through an RRC Connection Reestablishment Request message. Hereinafter, an RRC Connection Reestablishment Request message will be described as an example of a radio link failure related signal including indication information indicating a radio link failure of a cell associated with a second base station, but the present invention is not limited thereto. That is, as described above, the radio link failure related signal may be transmitted through higher layer signaling or may be transmitted through an existing RRC message or a newly defined RRC message.

Alternatively, the second base station may report a cell radio link failure occurrence associated with the second base station of the terminal through the interface between the base stations directly to the first base station.

For example, when the RLF indication signal of the cell associated with the second base station is transmitted through higher layer signaling (for example, an RRC Connection Reestablishment Request message), the SeNBFailure of the ReestablishmentCause is added to the second base station as described in FIG. 3. It can be used as an indication for indicating a radio link failure of an associated cell.

In addition, as described with reference to FIG. 4, a cell index may be further included to inform a cell related to which second base station that a radio link failure has occurred. For example, SCellFailure and ServCellIndex elements are added to a new RRC message or an existing RRC message or an RRC Connection Reestablishment Request message to include radio link failure of a cell associated with a second base station and index information of a cell associated with the second base station. And may be transmitted to the first base station.

4. Upon receiving the aforementioned radio link failure related signal, the first base station changes the configuration of the cell associated with the corresponding second base station and transmits it to the terminal.

For example, as described with reference to FIG. 5, the change configuration information for the cell associated with the second base station may be changed by changing the cell information associated with the second base station through a change of the SCellToAddMod, radioResourceConfigCommonSCell, and radioResourceConfigDedicatedSCell elements in the existing RRC Connection Reconfiguration procedure. The cell associated with the base station may be reset or a cell change associated with the second base station may be performed.

That is, the first base station may transmit the cell configuration information associated with the changed second base station to the terminal through the change of the above-described information elements (eg, SCellToAddMod, radioResourceConfigCommonSCell, radioResourceConfigDedicatedSCell element).

Alternatively, the cell associated with the second base station may be released, and the configuration of the cell associated with the first base station may be changed so that data transmitted to the cell associated with the second base station having the radio link failure is transmitted to the cell associated with the first base station. . That is, the radio bearer or the like set in the cell associated with the second base station may be changed to the cell associated with the first base station.

5. The terminal applies the cell configuration (or cell release associated with the second base station and cell configuration associated with the first base station) information associated with the changed second base station received from the base station. In addition, the base station transmits an activation request message to the corresponding terminal, the terminal may resume communication with the cell associated with the second base station according to the cell configuration associated with the changed second base station.

In this case, the first base station and the second base station may exchange necessary information (for example, cell configuration information related to the second base station of the terminal). In this case, information may be exchanged through an interface between base stations.

The cell associated with the second base station resuming the above-described communication may be a cell associated with the second base station previously connected or may be a cell associated with the new second base station. That is, communication with the cell associated with the second base station in which the radio link failure occurs may be resumed based on the configuration information transmitted by the base station, and may be associated with a new second base station instead of the cell associated with the second base station in which the radio link failure has occurred. It may also initiate communication with the cell. Or a cell associated with a third base station.

Second Embodiment When a cell associated with a second base station is in normal communication and a radio link failure is detected in a cell associated with the first base station.

6 is a diagram illustrating an example of operations of a terminal and a base station when a radio link failure occurs in a cell associated with a first base station according to another embodiment of the present invention.

In a method for handling a radio link failure (RFF) by a terminal according to another embodiment of the present invention, at least one cell associated with a first base station and at least one cell associated with a second base station are dually connected. And detecting a radio link failure occurrence in at least one or more cells of at least one or more cells associated with the first base station and at least one or more cells associated with the second base station. A method comprising transmitting a link failure related signal and receiving configuration information for radio link failure processing is provided.

In addition, the radio link failure related signal of the present invention may be transmitted to the second base station, and may include suspension indication information of a cell associated with the second base station.

Referring to FIG. 3, the terminal 601 forms a dual connection with the first base station 602 and the second base station 603 (S610), and detects a radio link failure occurrence in a cell associated with the first base station (S610). S620).

As described above, the radio link failure occurrence of the cell associated with the first base station may occur when out-of-synchronization occurs in the physical layer (more than a certain number of times) or random access (Random) in the MAC layer. It may be detected when an access problem occurs or when the maximum number of retransmissions is reached in the RLC layer.

When the UE 601 detects a radio link failure occurrence of the cell associated with the first base station (S620), the terminal 601 suspends the connection with the cell associated with the second base station. Alternatively, communication may be maintained until the terminal 601 is changed to the IDLE state.

If the terminal 601 has suspended the connection with the cell associated with the second base station, the terminal 601 explicitly transmits the hold indication information to the second base station 603 (S625) or implicitly the second. The suspension of data transmission and reception with the cell associated with the base station may be notified to the second base station 603.

That is, the terminal 601 of the present invention transmits an indication signal including the pending indication information to the second base station 603 (S625), or stops data transmission to the second base station 603 to associate with the second base station. The connection with the cell may be suspended (S635).

The terminal 601 according to another embodiment of the present invention, after the radio link failure-related signal transmission step, the display information indicating the retention of the relevant configuration information for the cell associated with the second base station held as a target base station for the RRC reset The method may further include transmitting and receiving the request information from the target base station and transmitting the relevant configuration information for the cell associated with the suspended second base station.

After the terminal 601 suspends the connection with the cell associated with the second base station, the terminal 601 performs a procedure for processing the radio link failure occurrence of the first base station and the cell associated with the first base station where the radio link failure occurred.

A procedure (eg, an RRC connection resetting procedure) for handling a radio link failure occurrence will be described in detail.

After the terminal 601 suspends the connection with the cell associated with the second base station, the terminal 601 transmits higher layer signaling to the first base station 602 to handle radio link failure occurrence of the cell associated with the first base station. For example, higher layer signaling may be an RRC Connection Reestablishment Request message. The first base station 602 transmits RRC connection reconfiguration information to the terminal 601, and the terminal 601 reestablishes connection of a cell associated with the first base station based on the received RRC connection reconfiguration information.

In this case, the cell associated with the reset first base station may be a cell associated with a first base station where an existing radio link failure has occurred, or may be a cell associated with a first base station other than the cell associated with the existing first base station. Or it may be a base station other than the first base station.

When the above-described RRC connection reconfiguration procedure is completed, the terminal 601 transmits an RRC connection reconfiguration complete message to the base station where the RRC connection is reestablished. Here, for the convenience of description, the first base station 602 and the RRC connection is described as being reset, but is not limited thereto.

The aforementioned RRC connection resetting complete message may include indication information indicating retention of related configuration information for the cell associated with the reserved second base station described above. Accordingly, the terminal 601 transmits an RRC connection reset complete message including the indication information to the first base station 602 (S630).

The terminal 601 receives a request for related configuration information for a cell associated with the second base station held from the reset first base station 602 (S640).

After receiving the request for the relevant configuration information for the cell associated with the reserved second base station, the terminal 601 may transmit the relevant configuration information for the cell associated with the reserved second base station to the reset first base station 602. (S650).

When the first base station 602 that is connected (ie, reset) receives the cell-related configuration information associated with the second base station that is suspended, the first base station 602 that is connected may transmit configuration information related to the cell associated with the second base station that is suspended. There is (S660). In other words, the terminal 601 receives signaling requesting transmission of cell related configuration information associated with the second base station held to the reset first base station 602 and cell related configuration information associated with the second base station withholding the connection. Transmit (S650).

The first base station 602 generates cell configuration information associated with the second base station based on the cell related configuration information associated with the reserved second base station received from the terminal 601. Thereafter, the terminal 601 may exchange information for accessing the cell associated with the second base station 603 and the second base station to communicate with (S655).

The terminal 601 receives the configuration information for the cell associated with the second base station from the first base station 602 (S660), and applies the change configuration of the cell associated with the second base station 603 based on the configuration information ( S670).

As another example, the configuration information may not be changed when the terminal withholds the cell associated with the second base station. If the configuration information received from the first base station 602 is not changed from the information previously set by the terminal 601, the previous configuration may be applied.

In addition, although not shown in FIG. 6, the terminal 601 may initiate communication by receiving an activation request message for initiating communication with a cell associated with a second base station configured from the first base station 602.

In this case, although FIG. 6 illustrates the cell associated with the second base station initiating communication as a cell associated with the existing reserved second base station, the cell configuration information associated with the second base station generated in the first base station 602 is described. Thus, communication with the cell associated with the new second base station may be initiated.

The activation request message may be transmitted to the second base station 603 to communicate with the terminal as well as the terminal 601.

Hereinafter, an example in which display information indicating retention of related configuration information for a cell associated with a second base station is included in an RRC connection reset complete message described with reference to FIG. 6 and an example of configuration information will be described with reference to the drawings. Explain.

FIG. 7 is a diagram illustrating an example of a message that may be included in a radio link failure related signal that may be included in a radio link failure related signal according to another embodiment of the present invention.

As described above, the terminal performs a resetting procedure with the first base station, and when resetting is completed, the terminal may transmit display information indicating retention of related configuration information for the cell associated with the reserved second base station.

As an example, the indication information may be included in the RRC connection reset complete message. That is, an Indication (SCellInfoAvailable-r12) that has cell related configuration information associated with the second base station held in the RRC Connection Re-establishment Complete message may be transmitted during the RRC connection reestablishment procedure.

Referring to FIG. 7, by setting the value of SCellInfoAvailable-r12 to 'true' and transmitting the same, cell-related configuration information retention associated with the reserved second base station may be indicated.

Alternatively, as another example, information indicating retention of cell related configuration information associated with the reserved second base station may be transmitted through a procedure such as an RRC connection establishment procedure or an RRC connection reconfiguration procedure.

In addition, the information indicating the retention of the cell-related configuration information associated with the reserved second base station may be repeatedly transmitted until the first base station recovers the cell information associated with the second base station for a predetermined time after the radio link failure occurs.

That is, each time the UE establishes or changes an RRC connection, the UE may include an indication indicating that the UE has cell-related configuration information associated with the reserved second base station.

8 is a diagram illustrating an example of a message that may be included in configuration information according to another embodiment of the present invention.

As described with reference to FIG. 6, the terminal receives a request signal for requesting cell related configuration information associated with a second base station suspended from the first base station.

The terminal transmits cell related configuration information associated with the second base station suspended to the first base station.

Referring to FIG. 8, cell-related configuration information associated with a reserved second base station may include cell bearer configuration for each cell and information such as SCellToAddModList, RadioResourceConfigCommonSCell, RadioResourceConfigDedicatedSCell, SCellToReleaseList, and the like. That is, information related to RadioResourceConfigCommonSCell, RadioResourceConfigDedicatedSCell, SCellToReleaseList, and radio bearer configuration may also be included.

Here, the SCell is described as an example of a cell associated with the second base station, and each information element may be represented by an information element indicating a second base station (eg, SeNB) instead of the SCell.

The first base station that has received the relevant configuration information may change the configuration information of the second base station and transmit it to the terminal.

Hereinafter, a method of processing when a radio link failure is detected in a cell associated with a first base station according to the second embodiment of the present invention described above will be described in more detail, for example, at each step.

1. The UE performs physical layer monitoring on each of a cell associated with a first base station and a cell associated with a second base station.

2. If a synchronization problem (eg, out-of-synchronization) occurs in the physical layer of the cell associated with the first base station, the terminal detects and declares a radio link failure for the cell associated with the first base station.

As another example for detecting the occurrence of a radio link failure, the RRC layer of the terminal may detect and declare a radio link failure when a predetermined number of out-of-synchronization indications are transmitted from a physical layer. have. Alternatively, when random access problem indication is transmitted in the MAC layer, the radio link failure may be detected and declared. Alternatively, when the maximum number of retransmissions is reached in the RLC layer, the radio link failure may be detected and declared.

3. If the terminal has a cell associated with the accessing second base station, the terminal suspends the cell associated with the second base station without releasing the cell associated with the second base station. Alternatively, communication may be continued until the terminal falls to an idle state without being suspended.

In the process of suspending a cell associated with a second base station, the terminal may explicitly send a radio link failure related signal including cell suspension indication information associated with the second base station explicitly to the second base station. . Alternatively, the cell suspension associated with the second base station may be implicitly informed by stopping transmission to the cell associated with the second base station.

4. Since the UE has failed in radio link, the UE performs an RRC connection reestablishment procedure for the cell associated with the first base station. In this case, the cell to be accessed may be a cell associated with a previously connected first base station, or may be another cell. In the RRC connection reestablishment procedure, the RRC connection reestablishment complete message may include the indication information indicating that cell-related configuration information associated with the second base station is held in the RRC connection reestablishment complete message.

That is, as an example, as described with reference to FIG. 7, by setting the value of SCellInfoAvailable-r12 to ture and transmitting the same, cell-related configuration information retention associated with the reserved second base station may be displayed.

Alternatively, as another example, information indicating retention of cell related configuration information associated with the reserved second base station may be transmitted through a procedure such as an RRC connection establishment procedure or an RRC connection reconfiguration procedure.

In addition, the information indicating the retention of the cell-related configuration information associated with the reserved second base station may be repeatedly transmitted until the first base station recovers the cell information associated with the second base station for a predetermined time after the radio link failure occurs.

5. The first base station that has received the indication information indicating the retention of the cell related configuration information associated with the second base station withheld transmits a message requesting the cell related configuration information associated with the second base station to the terminal.

6. The terminal transmits cell related configuration information associated with the second base station suspended.

As described with reference to FIG. 8, the cell-related configuration information associated with the reserved second base station may include cell-specific radio bearer configuration and information such as SCellToAddModList, RadioResourceConfigCommonSCell, RadioResourceConfigDedicatedSCell, SCellToReleaseList, and the like.

That is, information related to RadioResourceConfigCommonSCell, RadioResourceConfigDedicatedSCell, SCellToReleaseList, and radio bearer configuration may also be included.

Here, the SCell is described as an example of a cell associated with the second base station, and each information element may be an information element indicating a second base station (eg, SeNB) instead of the SCell.

7. The base station configures cell configuration information associated with the second base station of the terminal based on the cell-related configuration information received from the terminal and transmits it to the terminal. The cell configuration information associated with the second base station sent to the terminal may be the same as the information received from the terminal, or may be different.

The first base station may exchange information for dual connectivity between the second base station and the corresponding terminal based on cell configuration information associated with the second base station of the configured terminal.

8. The terminal that has received the cell configuration information associated with the second base station from the base station resets the cell associated with the second base station according to the information.

9. The base station transmits an activation request message to the terminal. The second base station may also transmit a message for resuming communication with the terminal.

10. The second base station resumes transmission with the terminal.

Embodiment 2-1: Another processing method when a cell associated with a second base station is normally communicating and a radio link failure is detected in a cell associated with a first base station.

FIG. 9 is a diagram illustrating another example of operations of a terminal and a base station when radio link failure occurs in a cell associated with a first base station according to another embodiment of the present invention.

According to another embodiment of the present invention, if a cell in which a radio link failure occurrence is detected is a cell associated with a first base station, the terminal indicates information indicating a radio link failure occurrence of a cell associated with the first base station to a second base station; A radio link failure related signal including at least one or more of failure cause information and index information indicating a cell in which a radio link failure occurs may be transmitted.

In addition, the terminal according to another embodiment of the present invention, the configuration information for the radio link failure processing received from the second base station, the RRC connection, RRC connection reconfiguration, RRC connection reset and handover to the second base station It may include any one of the information for performing the.

9, the terminal 901 configures a dual connection with the first base station 902 and the second base station 903 (S910).

As described above, the terminal 901 detects when a radio link failure occurs in a cell associated with the first base station (S920).

As described above, the radio link failure occurrence of the cell associated with the first base station may occur when out-of-synchronization occurs in the physical layer (more than a certain number of times) or random access (Random) in the MAC layer. An access problem may be detected when a problem occurs or when the maximum number of retransmissions is reached in the RLC layer.

When the cell in which the radio link failure is detected is a cell associated with the first base station, the terminal 901 transmits a radio link failure related signal including information indicating the radio link failure occurrence to the second base station 903 (S925). ).

The radio link failure related signal may include at least one or more of information indicating radio link failure occurrence of a cell associated with a first base station, radio link failure cause information, and index information indicating a cell where a radio link failure has occurred. .

Alternatively, the first base station 902 may transmit information on the occurrence of radio link failure and context information of the terminal 901 to the second base station 903.

The second base station 903 includes information necessary for changing the second base station 903 into a master base station for the corresponding terminal 901 based on the information received from the terminal 901 or the first base station 901. The setting information is transmitted to the terminal 903 (S930).

The terminal 901 applies the base station change configuration based on the received setting information (S940), and transmits a base station change configuration complete message to the second base station 903 (S945).

Accordingly, the second base station 903 may serve as the first base station 902 with respect to the corresponding terminal 901. For example, a cell serving as a reference for handover may be provided and may serve as a mobility anchor for the core network.

Hereinafter, the radio link failure processing method of the present invention according to the embodiment 2-1 will be described in more detail as an example at each step.

1. The UE performs physical layer monitoring on each of a cell associated with a first base station and a cell associated with a second base station.

2. If a synchronization problem (for example, out-of-synchronization) occurs in a physical layer of a cell operating as a PCell among cells associated with the first base station, the terminal may have a PCell having a synchronization problem among cells associated with the first base station. Declares a radio link failure.

As another example for detecting the occurrence of a radio link failure, the RRC layer of the terminal may declare a radio link failure when a predetermined number of out-of-synchronization indications are transmitted from a physical layer. Alternatively, when random access problem indication information is transmitted in the MAC layer, the radio link failure may be declared. Alternatively, when the maximum number of retransmissions is reached in the RLC layer, the radio link failure may be declared.

3. If the UE determines that a radio link failure has occurred in a cell associated with the first base station, the terminal reports the radio link failure of the cell associated with the first base station to the second base station.

A radio link failure related signal including information indicating radio link failure occurrence of a cell associated with a first base station is transmitted. Alternatively, the first base station may transmit information on radio link failure of the cell associated with the first base station of the terminal and context information of the terminal to the second base station.

4. The second base station transmits the configuration information including the configuration information for changing the second base station to the master base station for the terminal based on the information received from the terminal or the previous first base station to the terminal. The above configuration information may be transmitted through higher layer signaling, and may be, for example, an RRC Connection Reconfiguration message.

5. The terminal changes the second base station to the master base station according to the received configuration information. Here, changing the second base station to the first base station means that the second base station plays the role of the first base station as the above-described master base station.

Embodiment 2-2 Another processing method when the cell associated with the second base station is in normal communication and a radio link failure is detected in the cell associated with the first base station.

FIG. 10 is a diagram illustrating another example of operations of a terminal and a base station when radio link failure occurs in a cell associated with a first base station according to another embodiment of the present invention.

According to another embodiment of the present invention, if a cell in which a radio link failure is detected is a cell associated with a first base station, the terminal includes information for requesting the RRC connection reconfiguration with the second base station to the second base station. Send the relevant signal.

In addition, the configuration information for radio link failure processing received from the second base station according to another embodiment of the present invention may include information for performing RRC connection reconfiguration with the second base station.

Referring to FIG. 10, the terminal 1001 forms a dual connection with the first base station 1002 and the second base station 1003 (S1010).

As described above, the terminal 1001 detects a radio link failure in a cell associated with the first base station (S1020).

As described above, the radio link failure occurrence of the cell associated with the first base station may occur when out-of-synchronization occurs in the physical layer (more than a certain number of times) or random access (Random) in the MAC layer. An access problem may be detected when a problem occurs or when the maximum number of retransmissions is reached in the RLC layer.

When a radio link failure occurs, the first base station 1002 transmits a signal including information indicating the occurrence of the radio link failure and context information of the terminal 1001 to the second base station 1003 (S1030).

The terminal 1001 transmits a radio link failure related signal including information for requesting the RRC connection reconfiguration to the second base station 1003 (S1040).

For example, the radio link failure related signal may be transmitted through higher layer signaling. For example, higher layer signaling may be an RRC Connection Re-establshment Request message or a newly defined RRC message. For example, when the upper layer signaling is an RRC Connection Re-establshment Request message, the ReestablishmentCause may be set to MeNBFailure. The second base station 1003 may perform the RRC connection reestablishment procedure with the terminal 1001 by receiving the corresponding signal.

In addition, the second base station 1003 may request and receive the context information, the setting information, and the like for the terminal 1001 from the first base station 1002.

The second base station 1003 receives setting information including configuration information for changing to the master base station for the corresponding terminal 1001 based on the information received from the terminal 1001 or the first base station 1002. In step S1050. For example, the configuration information may be included in higher layer signaling and transmitted. For example, the configuration information may be an RRC Connection Re-establishment message.

The terminal 1001 applies the base station change configuration based on the received setting information and transmits a base station change configuration complete message to the second base station 1003 (S1060). For example, the base station change configuration complete message may be an RRC connection reset complete message.

Through the above RRC connection resetting procedure, the second base station 1003 and the terminal 1001 form an RRC connection, and the second base station 1003 may be configured for the corresponding terminal 1001 as a master base station. That is, the second base station 1003 may provide a cell serving as a reference for the handover to the terminal 1001 and may serve as a mobility anchor for the core network.

Third Embodiment: A radio link failure of a cell associated with a first base station (or a cell associated with a second base station) is detected (recovery in progress), followed immediately by a cell associated with a second base station (or a cell associated with a first base station). If the radio link failure is also detected.

11 is a diagram illustrating an example of an operation of a terminal according to an order of detecting radio link failure in a cell associated with a first base station and a second base station according to another embodiment of the present invention.

According to another embodiment of the present invention, when a radio link failure occurrence for a cell associated with a first base station and a second base station is detected at the same time or sequentially, the terminal determines a radio link failure for a cell associated with the first base station. Processing may be prioritized over radio link failure for the cell associated with the base station.

A case where a radio link failure occurs in a cell associated with a second base station and a radio link failure occurs in a cell associated with a first base station will be described with reference to FIG. 11.

The terminal detects the radio link failure of the cell associated with the second base station (S1110), (S1112). Thereafter, the terminal may proceed with the radio link failure processing procedure of the cell associated with the second base station as described above (S1114).

If the UE detects that the radio link failure of the cell associated with the first base station occurs during the operation S1114 (S1116 and S1118), the UE stops the radio link failure processing procedure of the cell associated with the second base station (S1120).

The terminal prioritizes the radio link failure processing procedure of the cell associated with the second base station (S1122).

12 is a diagram illustrating another example of a processing operation according to an order in which a radio link failure is detected in a cell associated with a first base station and a second base station by a terminal according to another embodiment of the present invention.

12 illustrates a case in which a radio link failure occurs in a cell associated with a first base station, and a radio link failure occurs in a cell associated with a second base station.

Referring to FIG. 12, when a radio link failure of a cell associated with a first base station occurs (S1200), the terminal detects this (S1202). Thereafter, the terminal may proceed with the radio link failure processing procedure of the cell associated with the first base station as described above (S1204).

In this case, however, the UE does not stop the radio link failure processing procedure of the cell associated with the first base station even when the radio link failure of the cell associated with the second base station is detected during the operation S1204 (S1206, S1208). Continue without (S1210).

In this case, the radio link failure processing procedure of the cell associated with the second base station may proceed after the radio link failure processing of the cell associated with the first base station is completed.

In other words, radio link failure detection and processing for a cell associated with a first base station operates over radio link detection and processing for a cell associated with a second base station.

That is, when a radio link failure is detected in a cell associated with the first base station and a radio link failure processing procedure is being performed, when a radio link failure is also detected in a cell associated with the second base station, Do not perform a radio link failure recovery procedure.

Conversely, when a radio link failure is detected in a cell associated with a second base station and a radio link failure processing procedure is being performed, a cell associated with the first base station is also detected when a radio link failure is detected. The radio link failure processing procedure of the cell is interrupted and the radio link failure processing procedure of the cell associated with the first base station is performed.

If radio link failure is simultaneously detected in a cell associated with the first base station and a cell associated with the second base station, the radio link failure detection and processing operations of the cell associated with the first base station may be prioritized.

Hereinafter, the operation of the terminal including each of the above-described embodiments will be described with reference to the drawings.

13 is a flowchart illustrating the operation of a terminal according to another embodiment of the present invention.

A terminal according to an embodiment of the present invention forms a dual connection with a first base station and a second base station, and can perform communication through at least one cell associated with the first base station and at least one cell associated with the second base station. There is (S1310).

The terminal detects a radio link failure occurrence for each cell associated with each of the first base station and the second base station (S1320).

When the radio link failure occurs, the terminal transmits a radio link failure related signal to any one of the first base station and the second base station (S1330).

In this case, as described above, according to each embodiment, the radio link failure related signal transmitted may include information indicating the occurrence of radio link failure of a cell associated with the second base station (Embodiment 1), or the second base station. It may also include hold indication information for the cell associated with (second embodiment).

Or, it may include information indicating the occurrence of radio link failure of the cell associated with the first base station (Embodiment 2-1).

Or, it may include information for requesting to reset the RRC connection with the second base station (Embodiment 2-2).

In addition, in the case of the second embodiment, after transmitting the radio link failure related signal, the method may further include performing a resetting procedure of a cell associated with the first base station where the radio link failure occurred.

Thereafter, the terminal includes receiving cell configuration information associated with the second base station from the connected (or reconfigured) first base station.

Even in this case, as described above, the cell configuration information associated with the second base station may be cell configuration information associated with the existing second base station, or may include information of a cell associated with the changed new second base station.

In addition, the first embodiment may include information for releasing the cell associated with the second base station where the radio link failure has occurred and changing the radio bearer of the cell associated with the second base station to the cell associated with the first base station.

Thereafter, the terminal may reset the cell associated with the second base station based on cell configuration information associated with the second base station, and receive an activation request message from the first base station to initiate communication with the cell associated with the second base station.

In the case of the embodiment 2-1, the terminal transmits a radio link failure related signal including information indicating the radio link failure occurrence to the second base station when the cell in which the radio link failure is detected is a cell associated with the first base station. (S1330).

Thereafter, the terminal receives configuration information including configuration information for configuring the second base station as the master base station from the second base station (S1340).

The terminal receives the configuration information, applies a configuration to change the second base station to the master base station, the second base station is changed to the master base station. Here, changing the second base station to the master base station means that the second base station is configured to perform a specific function performed by the first base station as described above. That is, the second base station serves as a mobility anchor toward the core network and performs a handover procedure when the cell associated with the second base station is changed.

Hereinafter, the operation of the first base station and the second base station according to each embodiment of the present invention will be described by way of example.

14 is a flowchart illustrating the operation of a first base station according to another embodiment of the present invention.

In a method for controlling a Radio Link Failure (RRF) processing of a terminal by a first base station according to another embodiment of the present invention, the radio link failure from a second base station providing additional radio resources to the terminal or the terminal Receiving a related signal, generating configuration information for radio link failure processing, and transmitting configuration information for radio link failure processing.

Referring to FIG. 14, the first base station may configure at least one cell together with the second base station by providing at least one cell to the terminal.

In this case, the terminal may perform the role of the aforementioned master base station.

The first base station receives a radio link failure related signal including information indicating the radio link failure generation for the cell associated with the second base station from the terminal (S1410). The radio link failure related signal may be received by higher layer signaling.

In addition, the first base station may receive a generation report from the second base station that includes information indicating the occurrence of radio link failure of the cell associated with the second base station.

The radio link failure related signal and the occurrence report from the second base station may overlap, and only the radio link failure related signal may be received. The aforementioned occurrence report may be transmitted and received through an interface configured between the first base station and the second base station.

When the first base station receives a radio link failure related signal from the terminal, the first base station may change the configuration information of the cell associated with the second base station and generate a new one (S1420).

In addition, the first base station may exchange configuration information of the cell associated with the changed / existing second base station with the second base station so that the terminal may perform multiple access with the cell associated with the first base station and the cell associated with the second base station. have. Even in this case, information may be exchanged through an interface between base stations.

The first base station transmits configuration information for radio link failure processing for the cell associated with the second base station to the terminal (S1430).

For example, the first base station receives a radio link failure related signal including information indicating the radio link failure occurrence of the cell associated with the second base station from the terminal, and then the terminal is a cell associated with the second base station from the first base station The configuration information for resetting or changing to a new cell is transmitted.

The configuration information according to an embodiment of the present invention releases the reset information of the cell associated with the second base station in which the radio link failure occurs, the change information of the cell associated with the second base station, and the cell associated with the second base station in which the radio link failure occurred. It may include any one of the information for changing the radio bearer to the cell associated with the first base station.

In addition, when the terminal configures a cell associated with the second base station after transmitting the configuration information about the cell associated with the second base station, the first base station activates for the terminal to access the terminal or the second base station to which the terminal accesses. The method may further include transmitting information requesting the request.

If the first base station according to another embodiment of the present invention includes indication information indicating retention of related configuration information for the cell associated with the second base station in which the radio link failure related signal is suspended, the cell associated with the second base station suspended The method may further include transmitting a signal for requesting relevant configuration information for the case of the second embodiment.

15 is a flowchart illustrating the operation of a second base station according to another embodiment of the present invention.

In a method for controlling a radio link failure (RFF) processing of a terminal by a second base station according to another embodiment of the present invention, the dual base station is provided with a first base station providing a radio resource to the terminal. And configuring a radio link failure related signal including information indicating any one of information indicating the occurrence of radio link failure of the cell associated with the first base station and information on pending indication of the cell associated with the second base station from the terminal or the first base station. Receiving may include.

In addition, the second base station according to another embodiment of the present invention, if the radio link failure-related signal includes information indicating the occurrence of the radio link failure of the cell associated with the first base station, RRC connection, RRC connection reconfiguration, The method may further include transmitting, to the terminal, configuration information for radio link failure processing including any one of information for resetting the RRC connection and performing handover of the terminal.

In addition, the second base station according to another embodiment of the present invention performs the RRC connection reconfiguration procedure with the terminal, if the radio link failure-related signal includes information indicating the occurrence of the radio link failure of the cell associated with the first base station It may further comprise a step.

Referring to FIG. 15, the second base station may configure additional connectivity by providing additional radio resources to the terminal together with the first base station (S1510).

Subsequently, the second base station signal from the terminal includes at least one of information indicating the occurrence of radio link failure for the cell associated with the first base station and information indicating pending indication for the cell associated with the second base station. It receives (S1520).

If a radio link failure occurs in a cell associated with the first base station as in the above-described second, second, second, or second embodiment, the second base station receives a radio link failure related signal. As described above, the information included in the radio link failure related signal may be different.

First, in the second embodiment described above, the second base station may receive a radio link failure related signal including the hold indication information.

In this case, the second base station suspends communication of the cell associated with the second base station based on the radio link failure related signal.

After the radio link failure of the cell associated with the first base station is processed, communication can be resumed according to the operation of the terminal.

If, as in the embodiment 2-1, the radio link failure related signal includes information indicating generation of radio link failure of the cell associated with the first base station, the second base station includes configuration information including configuration information necessary for changing the base station. It may transmit (S1530).

Thereafter, the terminal changes the second base station to the master base station based on the configuration information, and the second base station receives the base station change complete message and completes the base station change.

When the RRC connection reconfiguration request information of the terminal is included in the radio link failure related signal as in the embodiment 2-2, the second base station performs an RRC connection reconfiguration procedure with the terminal.

In this case, the configuration information may include information for resetting the RRC connection as described above.

In the third embodiment, the first base station and the second base station perform the procedure described above, but perform an operation necessary to prioritize the occurrence of radio link failure of the cell associated with the first base station.

Hereinafter, the configuration of the terminal and the base station in which all the operations according to the above-described embodiments of the present invention are performed will be briefly described once again.

16 is a diagram illustrating a configuration of a terminal according to another embodiment of the present invention.

Referring to FIG. 16, a terminal 1600 for processing a radio link failure (RLF) according to another embodiment of the present invention may include at least one cell associated with a first base station and at least one cell associated with a second base station. A controller 1620 for configuring dual connectivity with at least one cell, and a controller for detecting occurrence of radio link failure for at least one cell among at least one cell associated with the first base station and at least one cell associated with the second base station ( 1620, a transmitter 1630 for transmitting a radio link failure related signal to a first base station or a second base station, and a receiver 1610 for receiving configuration information for radio link failure processing.

In addition, the transmitter 1630 according to another embodiment of the present invention indicates the radio link failure occurrence of the cell associated with the second base station to the first base station when the cell detected that the radio link failure occurs is a cell associated with the second base station The radio link failure related signal including at least one or more information among the information, radio link failure cause information, and index information indicating a cell in which the radio link failure occurs may be transmitted.

In another embodiment, the transmitter 1630 is associated with a radio link failure including pending indication information of a cell associated with the second base station to the second base station when the cell in which the radio link failure is detected is a cell associated with the first base station. You can send a signal.

In another embodiment, the transmitting unit 1630 further transmits the indication information indicating the retention of the relevant configuration information for the cell associated with the second base station to the target base station for the RRC reset, and receives the request information from the target base station The relevant configuration information for the cell associated with the reserved second base station may be further transmitted.

In another embodiment, the transmitter 1630, when the cell detected that the radio link failure occurs is a cell associated with the first base station, information indicating the radio link failure generation of the cell associated with the first base station to the second base station, radio A radio link failure related signal including at least one of link failure cause information and index information indicating a cell in which a radio link failure occurs may be transmitted.

In another embodiment, the transmitter 1630 includes a radio link including information for requesting the second base station to reset the RRC connection with the second base station when the cell in which the radio link failure is detected is a cell associated with the first base station. Failure related signals can be sent.

In another embodiment, the controller 1620, if the radio link failure occurrence for the cell associated with the first base station and the cell associated with the second base station is detected simultaneously or sequentially, the radio link for the cell associated with the first base station The failure may be prioritized over radio link failure for the cell associated with the second base station.

In addition, the transmitter 1630 may transmit data, messages, and information to the first base station and the second base station, and the receiver 1610 may receive data and messages including the above-described information from the first base station and the second base station. Can be received.

The controller 1620 may control the overall operation of the terminal required to detect and process a radio link failure according to each embodiment described above.

17 is a diagram illustrating the configuration of a first base station and a second base station according to another embodiment of the present invention.

According to another embodiment of the present invention, a first base station generates a receiver 1730 for receiving a radio link failure related signal from a terminal or a second base station providing additional radio resources to the terminal and configuration information for radio link failure processing. And a transmitter 1720 for transmitting configuration information for radio link failure processing.

The above-described configuration information may include at least one of information indicating that a radio link failure related signal indicates a radio link failure occurrence of a cell associated with a second base station, radio link failure cause information, and index information for a cell in which a radio link failure has occurred. If included, the reset information of the cell associated with the second base station where the radio link failure occurred, the change information of the cell associated with the second base station and the cell associated with the second base station where the radio link failure occurred, and releases the radio to the cell associated with the first base station It may include any one of the information for changing the bearer.

In addition, the control unit 1710, as the radio link failure occurs in the cell associated with the second base station and the cell associated with the first base station, which is necessary for carrying out the above-described present invention, the overall necessary for handling each radio link failure. Control the operation of the first base station.

The transmitter 1720 and the receiver 1730 are used to transmit and receive signals, messages, and data necessary for carrying out the above-described present invention with the terminal and the second base station.

For example, the controller 1710 controls the operation of the first base station required to form a dual connection with the terminal together with the second base station providing additional radio resources to the terminal. In addition, it is possible to generate configuration information for radio link failure processing for the cell associated with the second base station.

The transmitter 1720 may transmit configuration information for radio link failure processing for the cell associated with the second base station to the terminal.

The receiver 1730 may receive a radio link failure related signal including information indicating the occurrence of a radio link failure for the cell associated with the second base station from the terminal.

Referring to FIG. 17 again, each configuration of the second base station will be described.

According to another embodiment of the present invention, the second base station includes a control unit 1710 for configuring dual connectivity to the terminal together with the first base station providing radio resources to the terminal and a cell associated with the first base station from the terminal or the first base station. The receiver 1730 may be configured to receive a radio link failure related signal including information indicating any one of radio link failure occurrences and information indicating one of the pending indication information of a cell associated with the second base station.

In addition, the second base station of the present invention, if the radio link failure-related signal includes information indicating the occurrence of radio link failure of the cell associated with the first base station, the terminal and the RRC connection, RRC connection reconfiguration, RRC connection reconfiguration and The apparatus may further include a transmitter 1720 for transmitting configuration information for radio link failure processing including information of any one of the information for performing the handover to the terminal.

In another embodiment, when the radio link failure related signal includes information indicating radio link failure occurrence of a cell associated with the first base station, the controller 1710 performs an RRC connection reconfiguration procedure with the terminal.

In addition, the control unit 1710, as the radio link failure occurs in the cell associated with the second base station and the cell associated with the first base station, which is necessary for carrying out the above-described present invention, the overall necessary for handling each radio link failure. Control the operation of the second base station.

The transmitter 1720 and the receiver 1730 are used to transmit and receive signals, messages, and data necessary for carrying out the above-described present invention with the terminal and the first base station.

For example, the controller 1710 controls the operation of the second base station required to form a dual connection with the terminal together with the first base station providing the radio resource to the terminal.

In addition, a base station change signal for radio link failure processing for a cell associated with the first base station may be generated and base station change may be performed.

The transmitter 1720 may transmit configuration information including information for changing the second base station to the master base station when the information indicating the radio link failure occurrence for the cell associated with the first base station is included.

As described above, according to the present invention, there is an effect of detecting the occurrence of radio link failure for each cell associated with the first base station and the cell associated with the second base station in an environment in which the terminal forms a dual connection with at least two base stations. .

In addition, if a radio link failure is detected, there is an effect of quickly recovering the radio link failure according to the base station associated with the cell where the radio link failure has occurred.

In addition, when a radio link failure occurs in a cell associated with any one base station in a dual connectivity environment, since data processing is possible through another base station, there is an effect of providing a method and apparatus for recovering a radio link failure considering this.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

CROSS-REFERENCE TO RELATED APPLICATION

This patent application is filed with Korean Patent Application No. 10-2013-0036870 filed on April 04, 2013 and Korea Patent Application No. 10-2013-0130502 filed on October 30, 2013, and December 2013 Claims No. 10-2013-0161241, filed in Korea on 23rd, claim priority under 35 USC § 119 (a) of the US Patent Act, all of which are incorporated by reference. Incorporated into the application. In addition, if this patent application claims priority for the same reason for countries other than the United States, all its contents are incorporated into this patent application by reference.

Claims (20)

In the method for the terminal to handle the Radio Link Failure (Radio Link Failure, RLF), Establishing dual connectivity with at least one cell associated with the first base station and at least one cell associated with the second base station; Detecting a radio link failure occurrence for at least one or more of at least one cell associated with the first base station and at least one cell associated with the second base station; Transmitting a radio link failure related signal to the first base station or the second base station; And Receiving setting information for the radio link failure processing. The method of claim 1, When the cell in which the radio link failure is detected is a cell associated with the second base station, The radio link including at least one of information indicative of radio link failure occurrence of a cell associated with the second base station, radio link failure cause information, and index information indicating a cell in which a radio link failure occurs to the first base station; How to send failure related signals. The method of claim 1, When the cell in which the occurrence of the radio link failure is detected is a cell associated with the first base station, And transmitting, to the second base station, the radio link failure related signal including hold indication information of a cell associated with the second base station. The method of claim 3, wherein After the radio link failure related signal transmission step, Transmitting indication information indicating retention of relevant configuration information for a cell associated with the second base station withheld to a target base station for RRC resetting; And Receiving request information from the target base station and transmitting relevant configuration information for the cell associated with the reserved second base station. The method of claim 1, When the cell in which the occurrence of the radio link failure is detected is a cell associated with the first base station, The radio link including at least one of information indicating radio link failure occurrence of a cell associated with the first base station, radio link failure cause information, and index information indicating a cell where a radio link failure has occurred, to the second base station; How to send failure related signals. The method of claim 1, When the cell in which the radio link failure occurs is a cell associated with the first base station, And transmitting the radio link failure related signal to the second base station, the radio link failure related signal including information for requesting the RRC connection reset with the second base station. The method of claim 1, Setting information for the radio link failure processing received from the second base station, And any one of information for performing an RRC connection, an RRC connection reconfiguration, an RRC connection reconfiguration, and a handover to the second base station with the second base station. The method of claim 1, When the occurrence of the radio link failure for the cell associated with the first base station and the cell associated with the second base station is detected simultaneously or sequentially, And processing the radio link failure for the cell associated with the first base station in preference to the radio link failure for the cell associated with the second base station. In the method of the first base station to control the radio link failure (RLF) processing of the terminal, Receiving a radio link failure related signal from the terminal or a second base station providing additional radio resources to the terminal; Generating setting information for the radio link failure processing; And Transmitting setting information for the radio link failure processing; The method of claim 9, The setting information, When the radio link failure related signal includes at least one or more of information indicating the occurrence of radio link failure of a cell associated with the second base station, radio link failure cause information, and index information for the cell where the radio link failure has occurred. , Releasing the reset information of the cell associated with the second base station where the radio link failure occurred, the change information of the cell associated with the second base station, and the cell associated with the second base station where the radio link failure occurred, and then radio the cell to the cell associated with the first base station. A method comprising any one of information for changing a bearer. In the terminal processing Radio Link Failure (RLF), A controller configured to establish a dual connection with at least one cell associated with the first base station and at least one cell associated with the second base station; A control unit detecting a radio link failure occurrence in at least one cell among at least one cell associated with the first base station and at least one cell associated with the second base station; A transmitter for transmitting a radio link failure related signal to the first base station or the second base station; And And a receiver configured to receive configuration information for the radio link failure processing. The method of claim 11, The transmitting unit, If the cell in which the radio link failure is detected is a cell associated with the second base station, information indicating radio link failure occurrence of the cell associated with the second base station to the first base station, radio link failure cause information, and radio link failure And a terminal for transmitting the radio link failure related signal including at least one or more pieces of information of the index information indicating the cell in which the cell has occurred. The method of claim 11, The transmitting unit, And a terminal for transmitting the radio link failure related signal including hold indication information of a cell associated with the second base station to the second base station when the cell in which the radio link failure is detected is a cell associated with the first base station. The method of claim 13, The transmitting unit, Further sending indication information indicating retention of relevant configuration information for the cell associated with the second base station held to the target base station for RRC resetting, And receiving request information from the target base station and further transmitting related configuration information for a cell associated with the suspended second base station. The method of claim 11, The transmitting unit, When the cell in which the radio link failure is detected is a cell associated with the first base station, information indicating radio link failure occurrence of the cell associated with the first base station to the second base station, radio link failure cause information, and radio link failure And a terminal for transmitting the radio link failure related signal including at least one or more pieces of information of the index information indicating the cell in which the cell has occurred. The method of claim 11, The transmitting unit, When the cell in which the radio link failure is detected is a cell associated with the first base station, a terminal for transmitting the radio link failure related signal including information for requesting to reset the RRC connection with the second base station to the second base station . The method of claim 11, Setting information for the radio link failure processing received from the second base station, And a terminal including any one of information for performing an RRC connection, an RRC connection reconfiguration, an RRC connection reconfiguration, and a handover to the second base station. The method of claim 11, The control unit, When the occurrence of the radio link failure for the cell associated with the first base station and the cell associated with the second base station is detected simultaneously or sequentially, And a terminal for processing radio link failure for the cell associated with the first base station in preference to radio link failure for the cell associated with the second base station. In the first base station for controlling the radio link failure (RLF) processing of the terminal, A receiver which receives a radio link failure related signal from the terminal or a second base station providing additional radio resources to the terminal; A controller configured to generate setting information for the radio link failure processing; And And a transmitter for transmitting configuration information for the radio link failure processing. The method of claim 19, The setting information, When the radio link failure related signal includes at least one or more of information indicating the occurrence of radio link failure of a cell associated with the second base station, radio link failure cause information, and index information for the cell where the radio link failure has occurred. , Releasing the reset information of the cell associated with the second base station in which the radio link failure has occurred, the change information of the cell associated with the second base station, and the cell associated with the second base station in which the radio link failure has occurred, A base station including any one of information for changing the bearer.

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