WO2018174654A1

WO2018174654A1 - Method for controlling mobility of terminal in heterogeneous network and apparatus therefor

Info

Publication number: WO2018174654A1
Application number: PCT/KR2018/003466
Authority: WO
Inventors: 김하성
Original assignee: 주식회사 케이티
Priority date: 2017-03-24
Filing date: 2018-03-23
Publication date: 2018-09-27

Abstract

The present disclosure relates to a dual connectivity-based mobility control procedure and system via an interface between a 5G base station and an LTE base station in a 5G non-standalone (NSA) network architecture which uses LTE EPC as a core network. An embodiment provides a method and an apparatus for performing a mobility control procedure of a terminal, by a master base station, the method comprising the steps of: determining starting of a secondary node addition procedure for setting a terminal context for a secondary node in order to provide the terminal with a radio resource of the secondary node; transmitting, to the secondary node, a secondary base station addition request message for requesting radio resource allocation for a specific E-UTRAN radio access bearer (E-RAB); and receiving, from the secondary node, secondary cell group radio resource configuration information to be additionally configured in the terminal.

Description

Method and apparatus for controlling mobility of terminal in heterogeneous network

The present disclosure relates to a dual connectivity-based mobility control procedure and system through an interface between a 5G base station and an LTE base station in a 5G non-standalone (NSA) network structure using LTE EPC as a core network.

Existing LTE supports bearer management for interworking with the LTE base station linked to the core network EPC through the S1 interface and application protocol.

Meanwhile, with the introduction of 5G networks, it has become essential to provide mobility. In particular, when the 5G base station uses the mmWave frequency (eg, 28 GHz) of the high frequency band, the coverage of the base station is expected to be smaller due to the characteristics of the frequency. Therefore, in this case, the frequency of the process of the user equipment to move the base station is increased and the handover (handover) or dual connectivity procedure for this also becomes very important.

In addition, the 5G network is likely to utilize the 5G non-standalone (NSA) network structure that uses LTE EPC as a core network as an initial stage of introduction, and dual connectivity-based mobility control procedures and systems through the interface between 5G and LTE base stations The demand for is increasing.

In this situation, 5G base station (hereinafter, may be referred to as 5G NB, NR NB, NG-RAN, NR base station, or gNB) and LTE base station (hereinafter, LTE NB) in a 5G NSA network structure using an existing LTE EPC as a core network. , dual connectivity can be used to support interface-based mobility between an eNB or a conventional base station. For this purpose, upgrade and modification of related procedures, messages, and information elements within the conventional X2 Application Protocol (X2AP) can be performed. Required.

In other words, in the NSA situation where the LTE base station and the 5G base station use the LTE EPC as a core network, a study on a specific procedure and method for configuring dual connectivity in a terminal is required.

In the above background, the present disclosure intends to propose a specific procedure for configuring dual connectivity using an LTE base station and a 5G base station in a terminal in a 5G NSA network.

In addition, the present disclosure is to propose a specific procedure for adding a 5G base station as a secondary base station to a terminal that communicates with the LTE base station.

In order to solve the above-mentioned problems, an embodiment of the present invention provides a method for performing a mobility control procedure of a terminal by a master base station, the secondary node for setting a terminal context in a secondary node to provide radio resources of the secondary node to the terminal. Determining the start of the node addition procedure, transmitting a secondary base station addition request message for requesting radio resource allocation for a specific E-UTRAN radio access bearer (E-RAB) to the secondary node, and additionally configuring the terminal from the secondary node It provides a method comprising the step of receiving the secondary cell group radio resource configuration information.

In addition, according to an embodiment of the present invention, a secondary base station performs a mobility control procedure of a mobile station. The secondary base station addition request for requesting radio resource allocation for a specific E-UTRAN radio access bearer (E-RAB) of a mobile station from a master node is provided. Secondary cell group radio resource for receiving message, RRM entity approving radio resource allocation for specific E-RAB, allocating transmission network resource according to E-RAB option, and additionally configuring in UE as master node It provides a method comprising the step of transmitting the configuration information.

In addition, according to an embodiment of the present invention, in a master base station performing a mobility control procedure of a terminal, determining a start of a secondary node addition procedure for establishing a terminal context at a secondary node in order to provide radio resources of a secondary node to the terminal. Secondary cell group radio resource configuration for additional configuration from the transmitter and the secondary node to the secondary node to send the secondary base station addition request message requesting the radio resource allocation for a specific E-RAB (E-UTRAN Radio Access Bearer) to the control unit and the secondary node It provides a master base station apparatus including a receiving unit for receiving information.

In addition, according to an embodiment, in a secondary base station performing a mobility control procedure of a terminal, a secondary base station addition request message for requesting radio resource allocation for a specific E-UTRAN radio access bearer (E-RAB) of a terminal from a master node is provided. Secondary cell group radio resource configuration information for additionally configuring the UE as a control unit and a master node that the receiving unit and the RRM entity approve radio resource allocation for a specific E-RAB and allocate transmission network resources according to the E-RAB option. It provides a secondary base station apparatus including a transmitting unit for transmitting.

According to the present disclosure, the dual connectivity can be configured through the LTE base station and the 5G base station to the terminal, it is possible to provide a communication data transmission and reception service utilizing a plurality of radio resources to the terminal in the NSA network.

In addition, according to the present disclosure, even when a core network of a 5G base station is not established, dual connectivity may be provided to a terminal using LTE EPC.

FIG. 1 is a diagram illustrating a 5G NSA network structure including a 5G base station and an LTE base station interworking with an LTE EPC according to an embodiment.

FIG. 2 is a diagram illustrating a 5G NSA network structure including a 5G base station and an LTE base station interworking with an LTE EPC according to another embodiment.

3 is a diagram illustrating a 5G base station connection addition scenario in an NSA network structure according to an embodiment.

4 is a diagram illustrating a 5G base station disconnection scenario in an NSA network structure according to an embodiment.

5 is a diagram for describing an operation of a master base station according to an exemplary embodiment.

6 is a diagram for describing an operation of a secondary base station according to an exemplary embodiment.

7 is a diagram for describing a structure of a secondary base station according to one embodiment.

8 is a diagram for describing a structure of a secondary base station structure including a central unit and a distribution unit, according to an exemplary embodiment.

9 is a diagram illustrating a dual connectivity configuration procedure using the secondary base station according to one embodiment.

10 is a diagram illustrating a configuration of a master base station according to one embodiment.

11 is a diagram for describing a configuration of a secondary base station according to one embodiment.

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.

In the present specification, the MTC terminal may mean a terminal supporting low cost (or low complexity) or a terminal supporting coverage enhancement. In the present specification, the MTC terminal may mean a terminal supporting low cost (or low complexity) and coverage enhancement. Alternatively, in the present specification, the MTC terminal may mean a terminal defined in a specific category for supporting low cost (or low complexity) and / or coverage enhancement.

In other words, in the present specification, the MTC terminal may mean a newly defined 3GPP Release-13 low cost (or low complexity) UE category / type for performing LTE-based MTC related operations. Alternatively, in the present specification, the MTC terminal supports enhanced coverage compared to the existing LTE coverage, or supports UE category / type defined in the existing 3GPP Release-12 or lower, or newly defined Release-13 low cost (or lower power consumption). low complexity) can mean UE category / type.

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 generic concept meaning a terminal in wireless communication. In addition, user equipment (UE) in WCDMA, LTE, and HSPA, as well as mobile station (MS) in GSM, user terminal (UT), and SS It should be interpreted as a concept that includes a subscriber station, a wireless device, and the like.

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. Other terms such as a base transceiver system, an access point, a relay node, a remote radio head (RRH), a radio unit (RU), and a small cell may be called.

That is, in the present specification, a base station or a cell is interpreted in a comprehensive sense to indicate some areas or functions covered by a base station controller (BSC) in CDMA, a NodeB in WCDMA, an eNB or a sector (site) in LTE, and the like. It is meant to cover various coverage areas such as mega cell, macro cell, micro cell, pico cell, femto cell and relay node, RRH, RU, small cell 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, and the like, according to the configuration of the radio region, become an embodiment of the base station. In ii), the base station may indicate the radio area itself to receive or transmit a signal from the viewpoint of the user terminal or the position of 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, and 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 a system such as LTE and LTE-advanced, a standard is configured by configuring uplink and downlink based on one carrier or a pair of carriers. The uplink and the downlink include a Physical Downlink Control CHannel (PDCCH), a Physical Control Format Indicator CHannel (PCFICH), a Physical Hybrid ARQ Indicator CHannel (PHICH), a Physical Uplink Control CHannel (PUCCH), an Enhanced Physical Downlink Control CHannel (EPDCCH), and the like. Control information is transmitted through the same control channel, and data is configured by a data channel such as a physical downlink shared channel (PDSCH) and a physical uplink shared channel (PUSCH).

On the other hand, control information may 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 coordinated multi-antenna transmission in which two or more transmission / reception points cooperate to transmit a signal. system), a cooperative multi-cell communication system. The CoMP system may include at least two multiple transmission / reception points and terminals.

The multiple transmit / receive point is at least one having a high transmission power or a low transmission power in a macro cell region, which is connected to an eNB or a macro cell (hereinafter referred to as an 'eNB') and wired controlled by an optical cable or an optical fiber to an eNB. May be RRH.

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 described in the form of 'sending and receiving a PUCCH, a PUSCH, a PDCCH, an EPDCCH, and a PDSCH.'

In addition, hereinafter, a description of transmitting or receiving a PDCCH or transmitting or receiving a signal through the PDCCH may be used as a meaning including transmitting or receiving an EPDCCH or transmitting or receiving a signal through the EPDCCH.

That is, the physical downlink control channel described below may mean PDCCH or EPDCCH, and may also be used to include both PDCCH and EPDCCH.

In addition, for convenience of description, the EPDCCH, which is an embodiment of the present invention, may be applied to the portion described as the PDCCH, and the EPDCCH may be applied to the portion described as the EPDCCH as an embodiment of the present invention.

Meanwhile, high layer signaling described below includes RRC signaling for transmitting RRC information including an RRC parameter.

The eNB performs downlink transmission to the terminals. The eNB includes downlink control information and an uplink data channel (eg, a physical downlink shared channel (PDSCH), which is a primary physical channel for unicast transmission, and scheduling required to receive the PDSCH. 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.

As a typical usage scenario in New Radio (NR), which is recently discussed by 3GPP, enhanced Mobile BroadBand (eMBB), massive machine type communication (MMTC), and Ultra Reliable and Low Latency Communication (URLLC) are being raised.

In this specification, frequencies, frames, subframes, resources, resource blocks, regions, bands, subbands, control channels, data channels, synchronization signals, various reference signals, various signals, and various messages related to NR (New Radio). May be interpreted as meaning used in the past or present, or various meanings used in the future.

For example, in the present specification, LTE and NR mean different radio access technologies, and a new radio access technology discussed in Release-15 of 3GPP will be described using NR. NR may include various differences from LTE to other frame structures, channels, and core network technologies, and may add various functions for high-bandwidth wireless transmission, high speed, and large data transmission.

Hereinafter, for convenience of understanding, a conventional radio access technology will be described in LTE, and a new radio access technology discussed in 3GPP will be described in NR. In addition, the base station may be an eNB using the LTE technology, may be a gNB using the NR technology, and will be described separately as necessary.

In addition, a cell in the present specification is used as a term encompassing a radio path, a radio link, a carrier, and the like for transmitting data, and one base station can transmit and receive data through a plurality of cells. Alternatively, the terminal may transmit and receive data using a plurality of cells through a cell controlled by two base stations. As will be described below, the description will be made by describing carrier aggregation when one base station controls a plurality of cells, and described as dual connectivity when using a plurality of cells controlled by two or more base stations.

듀얼 커넥티비티 동작(Dual Connectivity operation)Dual Connectivity operation

In the conventional LTE technology, a terminal supports a dual connectivity technology for simultaneously using two base station radio resources. Dual connectivity operation for multiple RX / TX UEs in RRC Connected state is configured to connect to two base stations connected via non-ideal backhaul to use radio resources provided by two different schedulers located at each base station.

In the case of dual connectivity, the terminal may transmit and receive data through a plurality of cells provided by two or more base stations, and in the present specification, a main base station (MeNB) or a main base station that forms an RRC connection with the terminal and serves as a reference for handover A base station that describes a master node and provides an additional cell to a terminal is described as a secondary base station (SeNB) or a secondary node.

On the other hand, as architectures and migration requirements for next-generation radio access technologies, the RAN architecture needs to support tight interworking between NR and LTE. It is expected that LTE dual connectivity technology can be utilized for tight interworking between NR and LTE. To this end, dual connectivity using an LTE base station and an NR base station and a dual connectivity technology using a plurality of NR base stations may be used. Dual connectivity in an NR environment can be defined as multi-connection. For example, multi connectivity may be defined as an operation mode of a terminal for using radio resources configured by an LTE base station and / or an NR base station.

In the present specification, a description will be made based on dual connectivity, but this is a term for exemplarily describing a case in which a plurality of base stations provide radio resources to a terminal, and should be understood as a meaning including multi connectivity, and in the case of multi connectivity. The content of the disclosure may apply. In addition, NR refers to the next generation radio access technology to which the technical document after 3GPP Rel-15 is applied, and is used as a term meaning a radio access technology that satisfies the requirements of IMT-2020.

In the present specification, in order to distinguish between LTE technology and NR technology, terms may be selected and used as follows.

In the following description, a base station using an LTE wireless network is described and described as an LTE base station, a 4G base station, a conventional base station, an eNB, an E-UTRAN NodeB, and an LTE NB, and a base station using an NR wireless network, which is a newly defined next-generation wireless access technology, is described. NR base station, 5G base station, gNB, 5G NB and the like will be described. In addition, the core network in the LTE network means EPC (Evolved Packet Core), the core network of the NR network means 5GC (5G Core Network). In addition, the terms necessary to describe the present disclosure will be described below to define the meaning of their use.

In addition, in the functional aspect of dual connectivity, the base station that forms an RRC connection with the terminal and serves as a reference for handover is described as a master base station or a master node (Master Node, MN), and a base station providing additional radio resources to the terminal is described. The description will be given as a base station or a secondary node (SN). In addition, the cell group provided by the master base station will be described and described as a master cell group (MCG), and the cell group provided by the secondary base station will be described and described as a secondary cell group (SCG). A cell supporting transmission of an uplink signal among a plurality of secondary cells included in the secondary cell group will be described as a primary secondary cell (PSCell).

The terms described above are described by way of example in order to facilitate understanding, and the present disclosure is not limited to the terms.

The existing LTE wireless network can support mobility between LTE base stations linked to the core network system EPC through S1, X2 interface and application protocol. As the 5G network is newly introduced, it is essential to provide interworking and mobility with the existing LTE base station. In particular, when the 5G base station uses a high band mmWave frequency (eg, 28 GHz frequency), smaller coverage is expected due to the frequency characteristics, so that the movement between the LTE base station and the 5G base station may occur more frequently. Therefore, the mobility support procedure for the terminal to support frequent mobility is very important. In addition, since 5G base stations are locally constructed at the beginning of 5G network construction, the dependency on the LTE network may be further increased.

In order to support interface-based mobility between 5G base stations and LTE base stations in a 5G non-standalone (NSA) network structure using the existing LTE EPC as a core network, related procedures in the existing X2 Application Protocol (X2AP) to use dual connectivity, Message and IE upgrade and modification will be required. Therefore, in the present disclosure, in order to support seamless mobility generated when the UE moves between 5G base station and LTE base station in LTE EPC based 5G NSA network structure, dual connectivity based mobility control based on direct interface and application protocol between 5G base station and LTE base station. To provide a procedure and system.

Hereinafter, a network structure in a situation where an LTE base station and a 5G base station are mixed will be described with reference to the drawings. In particular, in the present disclosure, the 5G base station will be described with reference to a network structure in which dual connectivity is configured in a terminal by interworking with an LTE base station, but may also be applied to a dual connectivity structure between 5G base stations.

FIG. 1 is a diagram illustrating a 5G NSA network structure including a 5G base station and an LTE base station interworking with an LTE EPC according to an embodiment, and FIG. 2 is a view illustrating a 5G base station and an LTE base station interworking with an LTE EPC according to another embodiment. A diagram illustrating a 5G NSA network structure.

1 and 2, the 5G network is composed of a SA (StandAlone) structure in which the 5G base station is connected to the 5G core network and a NSA (Non-StandAlone) structure in which the 5G base station is connected to the LTE EPC core network. Can be.

For example, the 5G NSA network includes an LTE EPC Core Network (CN), an LTE Radio Access Network (LTE RAN) 120 serving as a master base station, and a 5G Radio Access Network as a secondary base station. 5G RAN (130), and the EPC is connected to an external data network (DN) through a PGW (PDN Gateway).

The terminal is equipped with both a 5G / LTE wireless transceiver and a wireless protocol, and is connected to the 5G / LTE wireless interface (LTE-Uu / 5G-Uu). The terminal may be connected to the LTE base station and the 5G base station through Inter-RAT dual connectivity.

Due to the nature of the NSA network structure, the MME 110 that is responsible for mobility support and the SGW (Serving Gateway, 100) and the LTE base station 120, which are in charge of data processing, are respectively S1-C (or, S1-MME) and S1-U. Interworking with the interface, in particular MME 110 is responsible for mobility control, such as handover. In addition, the 5G base station 130 may be interworked with the SGW 100 through the S1-U interface. That is, the S1-C interface between the MME 110 and the 5G base station 130 is not configured, and the 5G base station 130 may include only the SGW 100 and the S1-U interface.

Alternatively, as shown in FIG. 2, the 5G base station 130 may not interwork with the SGW 100 through the S1-U interface. That is, the 5G base station 130 may be connected to the LTE base station 120 and may be associated with each entity (MME or SGW) of the LTE EPC through the LTE base station 120.

In the present specification, a structure like FIG. 1 will be described as NSA1, and a structure like FIG. 2 will be described as NSA2.

In addition, the interface and application protocol between the 5G base station 130 and the LTE base station 120 is defined as Xx and XxAP, respectively.

Meanwhile, as described above, the interface between the EPC and the 5G base station may be configured as an S1 interface, and the interface between the EPC and the LTE base station may also be linked to the S1 interface. For example, a plurality of 5G base stations and LTE base stations may be individually connected to one EPC. However, the 5G base station may include an eLTE base station capable of supporting not only 5G NB but also some functions of the 5G network. That is, the eLTE base station refers to a base station that satisfies the improved performance based on the LTE radio access technology as a radio access technology configured to satisfy some or all of the requirements of the aforementioned IMT-2020. Therefore, the description of the 5G base station in the present specification can be equally applied to the eLTE base station. .

Meanwhile, in order to configure dual connectivity in the aforementioned NSA 1 or NSA 2 structure, the EPC or the master base station (for example, the LTE base station) checks the capability information and the terminal capability information for the secondary base station (for example, the 5G base station). There is a need.

For example, the EPC or master base station may need to confirm at least one of the following information.

1) Secondary Node Type Information: The secondary node may include information on whether the secondary node is a base station using 5G, LTE, or eLTE.

2) S1 -U interface connection information of the secondary node: may include information on whether the secondary base station is connected to the SGW or not.

3) Bearer processing capability information of the secondary node: includes information on whether the secondary cell group (SCG) bearer or SCG split bearer (bearer supporting split transmission of the secondary node to the master node and the secondary node) can be processed. Can be.

4) Terminal wireless access support information: information on whether the terminal supports LTE-only wireless access, LTE and 5G wireless access simultaneously, whether to support eLTE and 5G wireless access simultaneously, and 5G-only wireless access. It may include.

5) Support network information of the terminal: may include information about the network structure supported by the terminal. For example, the terminal may include information on whether the terminal supports the NSA structure or whether the terminal supports the SA structure or the NSA and the SA structure at the same time.

Using at least one of the above-described information, the EPC or the master base station may limit or deny access of the terminal if necessary.

Hereinafter, a description will be given focusing on the above-described NSA1 network structure, but the present disclosure can be equally applied to the NSA2 network structure.

3 is a diagram illustrating a 5G base station connection addition scenario in an NSA network structure according to an embodiment, and FIG. 4 is a diagram illustrating a 5G base station connection release scenario in an NSA network structure according to an embodiment.

3 and 4, in the aforementioned NSA1 network structure, the terminal 300 may enter the coverage of the 5G base station 130 as it moves. In this case, the terminal 300 may configure the dual connectivity by using the 5G base station 130 to improve the data transmission and reception speed and the data throughput.

Accordingly, in the case of FIG. 3, the terminal 300 may configure dual connectivity in which the LTE base station 120 is the master base station and the 5G base station 130 is the secondary base station while maintaining the connection with the LTE base station 120. have. This requires an additional or reconfiguration procedure for the secondary base station.

In contrast, the terminal 300 configures dual connectivity with the LTE base station 120 within the coverage of the 5G base station 130 and may move out of the 5G base station 130 coverage according to the movement during operation. In this case, the terminal 300 requires a procedure of releasing the 5G base station 130 which is the secondary base station constituting the dual connectivity.

As described above, in the network structure in which the LTE base station 120 and the 5G base station 130 are deployed, the terminal needs to perform a dual connectivity configuration and release operation according to the movement. In particular, when the dual connectivity is configured as the 5G base station 130 as the secondary base station, a specific processing procedure on the Xx interface is required.

Hereinafter, a detailed embodiment of the present disclosure derived in accordance with such a request will be described with reference to the drawings.

Referring to FIG. 5, in order to provide a radio resource of the secondary node to the terminal, the master base station may perform the step of determining the start of the secondary node addition procedure for setting the terminal context in the secondary node (S510).

For example, the master base station may receive channel quality measurement results for the LTE base station and 5G base station of the terminal, and may determine whether to add the radio resource of the secondary node to the terminal based on the channel quality measurement result.

If necessary, the master base station or the secondary base station may transmit capability information of the terminal, the master base station and the secondary base station to the EPC entity (eg, MME), and the EPC entity may transmit the master base station and the secondary base station to the terminal based on the received information. It is possible to determine whether dual connectivity configuration is possible. If necessary, the EPC entity may restrict or deny connection or dual connectivity configuration of the terminal.

Meanwhile, the secondary node may be a secondary base station using a different radio access technology from the master base station. For example, the master base station may be an LTE base station, and the secondary base station may be a 5G base station.

The master base station may determine the start of the secondary node addition procedure for providing radio resources of the secondary node to the terminal based on at least one of the measurement information of the terminal and the result of determining whether to limit the MME. The master base station may set the terminal context to the secondary node through the secondary node addition procedure.

Meanwhile, the secondary base station may be composed of one central unit and one or more distributed units, and may be connected to the LTE EPC through the aforementioned NSA1 or NSA2 network structure.

The master base station may perform a step of transmitting a secondary base station addition request message requesting radio resource allocation for a specific E-RAB (E-UTRAN Radio Access Bearer) to the secondary node (S520). When the start of the secondary node addition procedure is determined, the master base station may transmit the secondary base station addition request message to the secondary node in order to configure the dual connectivity by adding the secondary node to the terminal.

For example, dual connectivity may be configured for a specific radio bearer (E-RAB), for which the master base station may request radio resource allocation for a specific E-RAB.

Meanwhile, the secondary base station addition request message may include at least one of UE capability information and radio resource configuration information of the master base station. In more detail, the terminal capability information may include a RAT-Type information element including information on a radio access technology supported by the terminal. In addition, the radio resource configuration information of the master base station includes configuration information on radio resources configured in the terminal by the master base station.

The RAT-Type information element of the terminal capability information may include at least one of whether the terminal supports each radio access technology, whether the terminal supports multi-connectivity using each radio access technology, and whether the terminal supports each radio access technology. May contain information. Such information may be included in the terminal capability RAT container list information by being included as a separate container in the RAT-Type information element.

The master base station may perform the step of receiving the secondary cell group radio resource configuration information for additional configuration from the secondary node to the terminal (S530). For example, when the secondary node approves radio resource allocation for the requested E-RAB, the master base station may receive radio resource configuration information for the secondary cell group added by configuring dual connectivity in the terminal.

For example, the RRM entity of the secondary node may approve radio resource allocation for the requested E-RAB and determine secondary cells excluding the primary secondary cell (PSCell) and the PSCell to be included in the secondary cell group. When the cells are determined, the secondary node may transmit the secondary cell group radio resource configuration information for configuring radio resources for the cell to the terminal in the RRC configuration message and transmit the information to the master base station.

The master base station may receive the secondary cell group radio resource configuration information including the RRC configuration message through the secondary base station addition request confirmation message.

Through this procedure, the master base station can add a secondary base station using another radio access technology as a dual connectivity base station of the terminal.

Additionally, when the base station addition request confirmation message is received, the master base station may transmit an RRC connection reconfiguration message to the terminal to instruct the terminal to add the secondary node as a dual connectivity base station. When the terminal configures the dual connectivity configuration using the secondary node in the terminal and reports to the master base station, the master base station transmits a message indicating that the secondary base station reconfiguration procedure is completed.

Thereafter, the terminal may establish a connection by performing a random access procedure with the secondary node using the PSCell of the secondary cell group.

Referring to FIG. 6, the secondary base station may perform a step of receiving a secondary base station addition request message for requesting radio resource allocation for a specific E-UTRAN radio access bearer (E-RAB) of a terminal from a master node (S610). ). When the allocation of radio resources for a specific E-RAB is determined by the master node and the start of the procedure for adding a secondary node for establishing a terminal context to the secondary node is determined, the secondary base station receives the secondary base station addition request message from the master node. can do.

The master node may refer to a master base station configured to use a different radio access technology from the secondary base station, and refers to a base station that becomes a reference for handover by configuring an RRC connection with the terminal. For example, the secondary base station may be a 5G base station, and the master base station may be an LTE base station. The secondary base station and the master base station can provide a radio resource to the terminal by configuring a dual connectivity.

The secondary base station addition request message may include at least one of UE capability information and radio resource configuration information of the master node. In more detail, the terminal capability information may include a RAT-Type information element including information on a radio access technology supported by the terminal. In addition, the radio resource configuration information of the master node includes configuration information on radio resources configured in the terminal by the master node.

The secondary base station may perform a step in which the RRM entity approves radio resource allocation for a specific E-RAB and allocates transmission network resources according to the E-RAB option (S620). For example, the RRM entity of the secondary base station may approve radio resource allocation for the requested E-RAB and determine secondary cells excluding the primary secondary cell (PSCell) and the PSCell to be included in the secondary cell group.

In addition, the RRM entity may allocate transport network resources based on the option information of the requested E-RAB. For example, the E-RAB option information may include at least one of QoS flow, split bearer status, characteristic information and type information of the E-RAB.

The RRM entity may determine whether to allocate the transmission network resources by considering whether the secondary base station can provide radio resources or process them when the bearer is a split bearer using the E-RAB option information.

The secondary base station may perform the step of transmitting the secondary cell group radio resource configuration information for additional configuration to the terminal to the master node (S630).

When the cells to be provided to the corresponding radio bearer (E-RAB) are determined, the secondary base station may transmit secondary cell group radio resource configuration information for configuring radio resources for the corresponding cell in the RRC configuration message to the master node. have. The secondary base station may transmit the secondary cell group radio resource configuration information including the aforementioned RRC configuration message through the secondary base station addition request confirmation message.

Through such a procedure, the secondary base station may determine the radio resource for configuring dual connectivity to the terminal and instruct the terminal.

Thereafter, the master node transmits the secondary cell group radio resource configuration information to the terminal, and if the terminal configures dual connectivity to the terminal using the radio resource configuration information for the secondary cell group, the secondary base station transmits a message for completion of configuration. Can be.

Thereafter, the secondary base station may configure dual connectivity by performing a random access procedure through the terminal and the PSCell.

Meanwhile, the secondary base station, which is a 5G base station, may be configured of a central unit and a distributed unit as described above.

Referring to FIG. 7, a 5G base station, which is a 5G radio access network (RAN), mainly includes a central unit 700 installed at a central station and a distributed

unit

710, 720 installed at a cell site. It can be configured separately. One CU 700 may be connected to one or more DUs 710 and 720 to configure a base station.

For example, the CU 700 may be connected to a DU 710 manufactured by vendor A, or may also be connected to a DU 720 manufactured by vendor B. FIG. CU 700 and

DUs

710 and 720 may be manufactured / installed by the same vendor or other vendors. In this case, the CU 700 and the DU 710 may be configured by the same vendor, and the CU 700 and the other DU 720 may be configured by different vendors.

The CU 700 and each of the

DUs

710 and 720 may be connected through a fronthaul interface. Hereinafter, the fronthaul interface, which is a connection interface between the CU 700 and the

DUs

710 and 720, will be described with Xf as an example. If necessary, the front hole may be described as a midhole.

Meanwhile, the

DUs

710 and 720 may include RF or antenna functions or may be separated separately. If separated, the three steps of the CU 700, the

DUs

710 and 720, and RF / antenna (not shown) may be performed. The base station may be designed in a separate structure.

The base station in the present embodiment may be implemented in a virtualized manner as an independent network function (Network Function, NF) of the PHY, MAC, RLC, PDCP, RRC type as a baseband function. In addition, the upper protocol and lower protocol functions of the base station may be appropriately separated into CU and DU, respectively, as shown in FIG. Alternatively, the independent network functions may be fixedly implemented without being virtualized as in the case of the LTE communication scheme.

FIG. 8 is a diagram for describing a structure of a secondary base station configuration including a central unit and a distribution unit, according to an embodiment.

The central unit and the distributed unit constituting the secondary base station (5G base station) may be configured in various types. Referring to FIG. 8, in the case of the type 1 base station 800, the central unit 801 configures the RRC and PDCP network functions, and the distributed unit 805 configures the RLC, MAC, and PHY network functions to form a separation structure. can do. Alternatively, the secondary base station, like the type 2 base station 810, the central unit 811 may configure the RRC, PDCP, RLC, MAC network function, the distribution unit 815 may configure only the PHY network function. In addition, some functions allowing non-real-time processing of the RLC or MAC may be distributed in the

central units

801 and 811 and some functions requiring real-time processing may be distributed and distributed in the

distribution units

805 and 815.

As such, the

central units

801, 811 may configure at least one network function of RRC, PDCP, RLC and MAC network functions, and the distributed

units

805, 815 may comprise at least one of RLC, MAC and PHY network functions. You can configure the network function. Alternatively, in the case of an integrated device in which an RF and an antenna are embedded, the RF may be included in the

distribution units

805 and 815. Therefore, in addition to the type 1 base station 800 and the type 2 base station 810 described above, various types of base station separation structures may be implemented. For example, the RLC and MAC layers have packet processing capabilities such as packet concatenation (Multiplexing, Assembling, etc.), segmentation (Packet Segmentation, De-multiplexing, etc.), packet reordering, and packet retransmission. Similar, integrated into a single layer or similar functions may be combined for high performance packet processing. Or, if necessary, certain network functions may be removed or not used.

Such a base station separation structure may be variously configured as necessary.

For example, the type 1 base station 800 may be more suitable for the mmWave base station for broadband transmission since it is easy to interwork between 5G and LTE / WiFi base station equipment through PDCP and requires a small capacity of fronthaul data transmission. The type 2 base station 810 is capable of short transmission delay and fast radio resource scheduling, but it is more suitable for a base station using a frequency of 6 GHz band or less because a large amount of fronthaul data transmission is required.

Meanwhile, a radio resource management (RRM) function may be added to the

DUs

805 and 815 to support mobility and the like separately from the

CUs

801 and 811. Alternatively, the RRM entity may be configured in the

CUs

801 and 811. Alternatively, a network function (eg, RRC) corresponding to a RAN control plane (CP) may be disposed in both the

CUs

801 and 811 and the

DUs

805 and 815.

Meanwhile, the aforementioned S1-U interface may be connected between the SGW and the

CUs

801 and 811. In particular, in the NSA structure, the protocol layer function for processing mapping between the bearer and the QoS flow located in or above the PDCP of the

CUs

801 and 811 may be deactivated (or unprocessed transmission). Here, the protocol layer for processing the mapping between the QoS flow and the bearer is described as a PDAP (Packet Data Association Protocol), but is not limited thereto. However, when the QoS flow function is supported in addition to bearer processing in the EPC and the UE, the PDAP layer may be dynamically activated.

As described above, the secondary base station which is a 5G base station may be divided into a central unit and a distributed unit.

As described above, in the EPC-based NSA network structure, the terminal connected to the LTE base station can be further connected to the 5G base station as it moves.

If 5G base station connection is added, it can be performed using UE / NB Capability Info Indication procedure through S1 interface and secondary base station addition / reconfiguration procedure through Xx interface. The procedure is similarly applicable to NSA2 network architecture.

The UE / NB Capability Info Indication procedure of the S1AP is a message used by the base station to transmit information of the terminal and the base station to the MME, and may be used by modifying or utilizing the conventional S1 message. The MME sends a UE / NB Capability Info Indication Acknowledge message to the base station to confirm the dual connectivity connection if the 5G base station can be connected based on the received terminal and base station information. If this is not allowed, a UE / NB Capability Info Indication Failure message is sent to the base station, including the reason for the failure, indicating that dual connectivity is not supported.

Hereinafter, the overall procedure for establishing a dual connectivity configuration by adding a secondary base station to a terminal including the above-described procedure will be described with reference to the drawings. Each message in the procedure described below is not limited to the terminology, and some procedure steps may be omitted or reordered.

Referring to FIG. 9, the MN 901 will be described assuming an LTE base station as a master node, and the SN 902 will be described assuming a 5G base station as a secondary node. In addition, each message is transmitted and received using a protocol such as S1AP or XxAP, and NB means NodeB as NodeB. Accordingly, NB is described as including both the master base station (MNB) and the secondary base station (SNB), and as necessary, the master base station 901 is described as MNB, and the secondary base station 902 is described as SNB. MNB should be understood as meaning MeNB, and SNB should be understood as meaning SgNB as 5G base station.

Detailed steps in the case of additionally connecting the 5G base station to the secondary base station 902 in the state connected with the master base station 901 may be performed as follows.

The terminal 900 measures 5G and LTE radio channel quality and reports it to the MN 901 (S910). The report may include information on cell quality and beam quality.

The MN 901, which is an LTE base station, transmits information of the terminal 900 and the

base stations

901 and 902 to the MME 903 (S915). That is, the MN 901 transmits the above-described UE / NB Capability Info Indication message to the MME 903.

The MME 903 determines whether the 5G base station 902 can be connected based on the information of the received terminal 900 and the

base stations

901 and 902. If necessary, the EPC may restrict or deny the connection or dual connectivity support of the terminal 900 according to the corresponding information.

The MME 903 sends a UE / NB Capability Info Indication Acknowledge message to the MN 901 to allow dual connectivity connection (S920), and the 5G base station 902 connection is not allowed. In this case, a UE / NB Capability Info Indication Failure message is sent to the MN 901 including the reason for the failure, indicating that the dual connectivity is not supported.

The MN 901 requests the radio resource allocation for a specific E-RAB to the SN 902 (S925). For example, MN 901 may send a secondary base station addition request message to SN 902. The secondary base station addition request message may include at least one of SCG-ConfigInfo, UE Capability information, and MCG-ConfigInfo. For example, the terminal capability information may include information about a radio access technology supported by the terminal 900 and may include a RAT-type information element including information on a radio access technology supported by the terminal. . The RAT-Type information element of the terminal capability information may include at least one of whether the terminal supports each radio access technology, whether the terminal supports multi-connectivity using each radio access technology, and whether the terminal supports each radio access technology. May contain information. Such information may be included in the terminal capability RAT container list information by being included as a separate container in the RAT-Type information element.

The SN 902 allocates radio resources when the requested radio resources are available and transmits them to the MN 901 including SCG-Config information (S930). For example, the SN 902 may request the requested E-RAB. If the radio resource allocation is approved, the secondary base station addition request confirmation message including radio resource configuration information for the secondary cell group added to configure the dual connectivity may be transmitted to the terminal 900. The secondary base station addition request acknowledgment message may include an RRC configuration message including information for configuring radio resources for the secondary cell except the primary secondary cell (PSCell) and the PSCell to be included in the secondary cell group.

If the SN 902 approves the configuration, the MN 901 transmits an RRC Connection Reconfiguration message to the terminal 900 (S935). Through this, the terminal 900 may set the configuration of the secondary cell group in the terminal to prepare for dual connectivity.

After applying the radio resource configuration for the secondary cell group, the terminal 900 transmits an RRC Connection Reconfiguration Complete message to the MN 901 (S940).

The MN 901 transmits a secondary base station reconfiguration complete message to the SN 902 indicating that the configuration of the secondary cell group radio resource of the terminal is completed (S945).

The terminal 900 synchronizes with the PSCell, and performs a random access procedure with the SN 902 (S950).

The MN 901 performs SN status transfer of the transport packet (S955), and when data from the SGW 904 is received, performs a data forwarding procedure of forwarding it to the SN 902 (S960). .

Thereafter, the MN 901 transmits an E-RAB modification indication message to update the data path to the MME 903 of the EPC (S965), and the MME 903 performs a bearer modification procedure with the SGW 904. (S970).

The SGW 904 transmits the end market packet to the MN 901, and the MN 901 forwards it to the SN 902 (S975). The MME 980 forwards a modification confirmation message for the E-RAB modification to the MN 901 to complete the data path update procedure.

As described above, the present disclosure provides a dual connectivity based mobility support procedure generated when the UE moves between the 5G base station and the LTE base station in the LTE EPC-based 5G NSA network structure, thereby providing service continuity, and establishing and operating a 5G wireless network. This has the effect of providing significant savings.

Hereinafter, configurations of a master base station and a secondary base station capable of performing some or all of operations of the master base station and the secondary base station described with reference to FIGS. 1 to 9 will be described. Each configuration may be performed by a control module, a transmission module, and a reception module configured in the base station, or may be performed by one electronic control unit or a plurality of electronic control units.

Referring to FIG. 10, the master base station 1000 includes a control unit 1010 and a secondary node for determining the start of a secondary node addition procedure for setting a terminal context in the secondary node in order to provide radio resources of the secondary node to the terminal. Secondary cell group radio resource configuration information for additional configuration to the terminal from the transmitter 1020 and the secondary node for transmitting a secondary base station addition request message for requesting radio resource allocation for a specific E-RAB (E-UTRAN Radio Access Bearer) It may include a receiving unit 1030 for receiving.

For example, the receiver 1030 may receive channel quality measurement results for the LTE base station and 5G base station of the terminal, and the controller 1010 may determine whether to add the radio resource of the secondary node to the terminal based on the channel quality measurement result. have.

If necessary, the transmitter 1020 may transmit capability information of the terminal, the master base station, and the secondary base station to the EPC entity (for example, the MME), and the EPC entity may transmit the master base station and the secondary base station to the terminal based on the received information. It may be determined whether the dual connectivity configuration used is possible. If necessary, the EPC entity may restrict or deny connection or dual connectivity configuration of the terminal.

The controller 1010 may determine initiation of a secondary node addition procedure for providing radio resources of the secondary node to the terminal based on at least one of measurement information of the terminal and a result of determining whether to restrict the MME.

When the start of the secondary node addition procedure is determined, the transmitter 1020 may transmit a secondary base station addition request message to the secondary node in order to configure the dual connectivity by adding the secondary node to the terminal. For example, dual connectivity may be configured for a specific radio bearer (E-RAB), and for this purpose, the transmitter 1020 may request radio resource allocation for a specific E-RAB. The secondary base station addition request message may include at least one of UE capability information and radio resource configuration information of the master base station. In more detail, the terminal capability information may include a RAT-Type information element including information on a radio access technology supported by the terminal. In addition, the radio resource configuration information of the master base station includes configuration information on radio resources configured in the terminal by the master base station. The RAT-Type information element of the terminal capability information may include at least one of whether the terminal supports each radio access technology, whether the terminal supports multi-connectivity using each radio access technology, and whether the terminal supports each radio access technology. May contain information. Such information may be included in the terminal capability RAT container list information by being included as a separate container in the RAT-Type information element.

In addition, when the secondary node approves radio resource allocation for the requested E-RAB, the receiving unit 1030 may configure radio connectivity for the terminal and receive radio resource configuration information for the secondary cell group added. For example, when the cells of the secondary node are determined, the receiver 1030 may receive the secondary cell group radio resource configuration information for configuring radio resources for the corresponding cell in the terminal in the RRC configuration message. In addition, the receiver 1030 may receive the secondary cell group radio resource configuration information including the RRC configuration message through the secondary base station addition request confirmation message.

In addition, when the base station addition request confirmation message is received, the transmitter 1020 may transmit an RRC connection reconfiguration message to the terminal to instruct the terminal to add the secondary node as the dual connectivity base station. In addition, when the terminal applies the dual connectivity configuration using the secondary node in the terminal, the receiving unit 1030 may receive a configuration completion message thereof. Thereafter, the transmitter 1020 transmits a message indicating that the secondary base station reconfiguration procedure is completed to the secondary node.

In addition, the control unit 1010 may control the overall operation of the master base station 1000 for configuring the multi-connectivity to the terminal by using a plurality of base stations using different radio access technologies in the above-described embodiments.

Also, the transmitter 1020 and the receiver 1030 are used to transmit and receive signals, messages, and data necessary for performing the above-described embodiments with a terminal, an EPC entity, and a secondary base station.

Referring to FIG. 11, the secondary base station 1100 includes a receiver 1130 that receives a secondary base station addition request message for requesting radio resource allocation for a specific E-UTRAN radio access bearer (E-RAB) of a terminal from a master node; Secondary cell group radio resource configuration information for the RRM entity to approve radio resource allocation for a specific E-RAB and additionally configure the UE as a control unit 1110 and a master node for allocating transmission network resources according to the E-RAB option. It may include a transmitting unit 1120 for transmitting.

The receiver 1130 determines a radio resource allocation for a specific E-RAB by the master node, and when the start of the secondary node addition procedure for setting a terminal context in the secondary node is determined, a secondary base station addition request message is received from the master node. Can be received. For example, the secondary base station addition request message may include at least one of UE capability information and radio resource configuration information of the master node. In more detail, the terminal capability information may include a RAT-Type information element including information on a radio access technology supported by the terminal. In addition, the radio resource configuration information of the master node includes configuration information on radio resources configured in the terminal by the master node. The RAT-Type information element of the terminal capability information may include at least one of whether the terminal supports each radio access technology, whether the terminal supports multi-connectivity using each radio access technology, and whether the terminal supports each radio access technology. May contain information. Such information may be included in the terminal capability RAT container list information by being included as a separate container in the RAT-Type information element.

In addition, the controller 1110 may approve radio resource allocation for the requested E-RAB and determine secondary cells excluding the primary secondary cell (PSCell) and the PSCell to be included in the secondary cell group. In addition, the controller 1110 may allocate a transmission network resource based on the requested information of the E-RAB. For example, the E-RAB option information may include at least one of QoS flow, split bearer status, characteristic information and type information of the E-RAB. The controller 1110 may determine whether to allocate the transmission network resource by considering whether the secondary base station can provide radio resources or whether the corresponding bearer can process the split bearer using the E-RAB option information. have.

When the cells to be provided to the corresponding radio bearer (E-RAB) are determined, the transmitter 1120 includes the secondary cell group radio resource configuration information for configuring radio resources for the corresponding cell in the RRC configuration message to the master node. Can transmit The transmitter 1120 may transmit the secondary cell group radio resource configuration information including the aforementioned RRC configuration message through the secondary base station addition request confirmation message.

In addition, the controller 1110 may control the overall operation of the secondary base station 1100 for configuring the multi-connectivity to the terminal by using a plurality of base stations using different wireless access technologies.

In addition, the transmitter 1120 and the receiver 1130 are used to transmit and receive signals, messages, and data necessary for performing the above-described embodiments with a terminal, an EPC entity, and a master base station.

The standard contents or standard documents mentioned in the above embodiments are omitted to simplify the description of the specification and form a part of the present specification. Therefore, the addition of the contents of the standard and part of the standard documents to the specification or the description in the claims should be construed as falling within the scope of the present invention.

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 APPLICATIONCROSS-REFERENCE TO RELATED APPLICATION

This patent application is filed with the Korean Patent Application No. 10-2018-0033250 filed on March 22, 2018 and the Korean Patent Application No. 10-2017-0037934 filed on March 24, 2017 in the United States. Priority is claimed under section (a) (35 USC § 119 (a)), all of which is incorporated by reference in this patent 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

In the method for the master base station performs the mobility control procedure of the terminal,

Determining initiation of a secondary node addition procedure for establishing a terminal context at the secondary node to provide radio resources of the secondary node to the terminal;

Transmitting a secondary base station addition request message for requesting radio resource allocation for a specific E-RAB (E-UTRAN Radio Access Bearer) to the secondary node; And

Receiving secondary cell group radio resource configuration information for additional configuration from the secondary node to the terminal.
The method of claim 1,

The secondary node,

A secondary base station configured to use a different radio access technology from the master base station,

And the master base station and the secondary base station configure dual connectivity for the terminal.
The method of claim 2,

The secondary base station,

A central unit and one or more distributed units coupled to the central unit, the method comprising the core network of the master base station.
The method of claim 1,

The secondary base station addition request message,

And at least one of UE capability information and radio resource configuration information of the master base station.
The method of claim 4, wherein

The terminal capability information,

And information about a radio access technology supported by the terminal.
The method of claim 1,

The secondary cell group radio resource configuration information,

If the radio resource allocation for the particular E-UTRAN Radio Access Bearer (E-RAB) is approved by the RRM entity of the secondary node,

And an RRC configuration message including radio resource configuration information for a primary secondary cell (PSC) included in the secondary cell group.
In the method of the secondary base station performs the mobility control procedure of the terminal,

Receiving a secondary base station addition request message for requesting radio resource allocation for a specific E-UTRAN radio access bearer (E-RAB) of a terminal from a master node;

An RRM entity approving radio resource allocation for the specific E-RAB and allocating transmission network resources according to the E-RAB option; And

And transmitting secondary cell group radio resource configuration information for additional configuration to the terminal to the master node.
The method of claim 7, wherein

The master node,

A master base station configured to use a different radio access technology from the secondary base station,

And the secondary base station and the master base station configure dual connectivity for the terminal.
The method of claim 8,

The secondary base station,

A central unit and one or more distributed units coupled to the central unit, the method comprising the core network of the master base station.
The method of claim 7, wherein

The secondary base station addition request message,

And at least one of UE capability information and radio resource configuration information of the master node.
The method of claim 10,

The terminal capability information,

And information about a radio access technology supported by the terminal.
The method of claim 7, wherein

The secondary cell group radio resource configuration information,

And an RRC configuration message including radio resource configuration information for a primary secondary cell (PSC) included in the secondary cell group.
In the master base station performing the mobility control procedure of the terminal,

A control unit for determining a start of a secondary node addition procedure for setting a terminal context in the secondary node in order to provide the terminal with radio resources of the secondary node;

A transmitter for transmitting a secondary base station addition request message for requesting radio resource allocation for a specific E-RAB (E-UTRAN Radio Access Bearer) to the secondary node; And

And a receiving unit for receiving secondary cell group radio resource configuration information for additional configuration from the secondary node to the terminal.
The method of claim 13,

The secondary node,

A secondary base station configured to use a different radio access technology from the master base station,

The master base station and the secondary base station is configured to configure the dual connectivity for the terminal.
The method of claim 14,

The secondary base station,

And a central unit and at least one distributed unit connected to the central unit, wherein the master base station is configured to use the core network of the master base station.
The method of claim 13,

The secondary base station addition request message,

And at least one of UE capability information and radio resource configuration information of the master base station.
The method of claim 16,

The terminal capability information,

Master base station, characterized in that it comprises information on the radio access technology supported by the terminal.
The method of claim 13,

The secondary cell group radio resource configuration information,

If the radio resource allocation for the particular E-UTRAN Radio Access Bearer (E-RAB) is approved by the RRM entity of the secondary node,

And a RRC configuration message including radio resource configuration information for a primary secondary cell (Primary SCell, PSCell) included in the secondary cell group.