WO2018231021A1 - Method and apparatus for processing mobility in dual rrc system - Google Patents

Abstract

The present disclosure relates to a communication technique for convergence of IoT technology and a 5G communication system for supporting a higher data transfer rate beyond a 4G system, and a system therefor. The present disclosure can be applied to intelligent services (e.g., smart homes, smart buildings, smart cities, smart or connected cars, health care, digital education, retail business, and services associated with security and safety) on the basis of 5G communication technology and IoT-related technology. Disclosed are a method and an apparatus for improving mobility-related performance when a dual connectivity is performed using dual RRC.

Description

Method and apparatus for handling mobility in dual RRC system

This patent relates to a technique for performing dual connectivity using Dual RRC.

In order to meet the increasing demand for wireless data traffic since the commercialization of 4G communication systems, efforts are being made to develop improved 5G communication systems or pre-5G communication systems. For this reason, a 5G communication system or a pre-5G communication system is called a system after a 4G network (Beyond 4G Network) or a system after an LTE system (Post LTE). In order to achieve high data rates, 5G communication systems are being considered for implementation in the ultra-high frequency (mmWave) band (eg, such as the 60 Gigabit (60 GHz) band). In order to mitigate the path loss of radio waves in the ultra-high frequency band and increase the propagation distance of radio waves, beamforming, massive array multiple input / output (FD-MIMO), and FD-MIMO are used in 5G communication systems. Array antenna, analog beam-forming, and large scale antenna techniques are discussed. In addition, in order to improve the network of the system, 5G communication systems have advanced small cells, advanced small cells, cloud radio access network (cloud RAN), ultra-dense network (ultra-dense network) , Device to Device communication (D2D), wireless backhaul, moving network, cooperative communication, Coordinated Multi-Points (CoMP), and interference cancellation The development of such technology is being done. In addition, in 5G systems, Hybrid FSK and QAM Modulation (FQAM) and Slide Window Superposition Coding (SWSC), Advanced Coding Modulation (ACM), and FBMC (Filter Bank Multi Carrier) and NOMA are advanced access technologies. (non orthogonal multiple access), and sparse code multiple access (SCMA) are being developed.

Meanwhile, the Internet is evolving from a human-centered connection network in which humans create and consume information, and an Internet of Things (IoT) network that exchanges and processes information between distributed components such as things. The Internet of Everything (IoE) technology, which combines big data processing technology through connection with cloud servers and the like, is emerging. In order to implement the IoT, technical elements such as sensing technology, wired / wireless communication and network infrastructure, service interface technology, and security technology are required, and recently, a sensor network for connection between things, a machine to machine , M2M), Machine Type Communication (MTC), etc. are being studied. In an IoT environment, intelligent Internet technology (IT) services can be provided that collect and analyze data generated from connected objects to create new value in human life. IoT is a field of smart home, smart building, smart city, smart car or connected car, smart grid, health care, smart home appliances, advanced medical services, etc. through convergence and complex of existing information technology (IT) technology and various industries. It can be applied to.

Accordingly, various attempts have been made to apply the 5G communication system to the IoT network. For example, technologies such as sensor network, machine to machine (M2M), machine type communication (MTC), and the like, are implemented by techniques such as beamforming, MIMO, and array antennas. It is. Application of cloud radio access network (cloud RAN) as the big data processing technology described above may be an example of convergence of 5G technology and IoT technology.

In the heterogeneous RAT system, which is being studied recently, when two different RATs are attached to the common core system, the master node (MN) and the secondary node (SN) can operate with the RRC respectively. In this case, since the master node (MN) and the secondary node (SN) may operate with RRC, respectively, in this case, a method for mobility processing is needed.

Disclosure of Invention An object of the present invention is to disclose a method and apparatus for improving mobility-related performance when performing dual connectivity using dual RRC.

In a wireless communication system supporting dual connectivity according to an embodiment of the present invention for solving the above problems, a control method of a terminal is when a connection with a first master node (MN) is released. Transmitting an RRC connection re-establishment request message including identifier information on a secondary node (SN) to a second master node (MN); When the context information about the terminal is included, the method may include receiving an RRC connection reestablishment message from the second MN.

Meanwhile, in a wireless communication system supporting dual connectivity according to another embodiment of the present invention, when a terminal is disconnected from a transceiver for transmitting and receiving a signal and a first master node (MN), the secondary is disconnected. Sends an RRC connection re-establishment request message including identifier information about a node (secondary node, SN) to a second master node (MN), the second MN to the terminal When the context information is included, the controller may control the transceiver to receive the RRC connection reestablishment message from the second MN.

Meanwhile, in a wireless communication system according to another embodiment of the present invention, a method for controlling a master node (MN) may include a secondary node (SN) from a terminal from which a connection with another master node (MN) is released. Receiving an RRC connection re-establishment request message including the identifier information for the information and the context information for the terminal, and transmitting the RRC connection re-establishment message to the terminal It may include.

On the other hand, in a wireless communication system according to another embodiment of the present invention, the master node (MN) is a secondary node (MN) from the terminal that is disconnected from the transceiver for transmitting and receiving signals and other master node (MN) Receiving an RRC connection re-establishment request message including identifier information for the secondary node (SN), and if the context information for the terminal includes, and transmits an RRC connection reestablishment message to the terminal It may include a control unit for controlling the transceiver to.

According to the present invention, when performing dual connectivity using Dual RRC, the throughput of the terminal can be increased by efficiently performing a procedure related to mobility.

1 is a diagram illustrating a system to which the present invention is applied.

FIG. 2 is a diagram illustrating a sequence diagram describing Embodiment 1. FIG.

3 is a diagram illustrating a sequence for describing Embodiment 2. FIG.

4 is a diagram showing a sequence diagram for explaining a sequence diagram for explaining the third embodiment.

FIG. 5 is a diagram for explaining a fourth embodiment.

FIG. 6 is a diagram illustrating a sequence diagram illustrating case 1 according to a fourth embodiment.

FIG. 7 is a sequence diagram illustrating case 2 according to a fourth embodiment.

8 is a sequence diagram illustrating case 3 according to the fourth embodiment.

FIG. 9 is a diagram illustrating a sequence diagram illustrating case 4 according to a fourth embodiment.

FIG. 10 is a sequence diagram illustrating an embodiment in which an SN RRCConnectionReconfigurationComplete is transmitted to an SCG SRB and an MR is also transmitted to the SCG SRB.

FIG. 11 illustrates a sequence diagram of an embodiment in which an SN RRCConnectionReconfigurationComplete is transmitted to an MCG SRB and an MR to an SCG SRB.

12 is a sequence diagram illustrating an embodiment in which SN RRCConnectionReconfigurationComplete is transmitted to an SCG SRB and an MR to an MCG SRB.

FIG. 13 illustrates a sequence diagram of an embodiment in which an SN RRCConnectionReconfigurationComplete is transmitted to an MCG SRB and an MR is also transmitted to the MCG SRB.

FIG. 14 illustrates a sequence diagram of an embodiment in which a UL path is set differently although carried in respective RRCconnectionReconfiguration messages of separate measConfig.

15 is a diagram showing a sequence diagram for describing the sixth embodiment.

16A to 16C illustrate a sequence diagram for an embodiment of a master node (MN) initiated SCG change indication.

17A to 17C illustrate a sequence diagram of an embodiment in which an SN sends an MN indicating an operation required for an SCG change indication IE in an SN modification required message by an MN.

18 is a diagram illustrating a structure of a terminal according to an embodiment of the present invention.

19 is a diagram showing the structure of a base station according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In describing the embodiments, descriptions of technical contents which are well known in the technical field to which the present invention belongs and are not directly related to the present invention will be omitted. This is to more clearly communicate without obscure the subject matter of the present invention by omitting unnecessary description.

For the same reason, in the accompanying drawings, some components are exaggerated, omitted or schematically illustrated. In addition, the size of each component does not fully reflect the actual size. The same or corresponding components in each drawing are given the same reference numerals.

Advantages and features of the present invention, and methods for achieving them will be apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various forms, and only the embodiments of the present invention make the disclosure of the present invention complete and the general knowledge in the technical field to which the present invention belongs. It is provided to fully convey the scope of the invention to those skilled in the art, and the present invention is defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

At this point, it will be understood that each block of the flowchart illustrations and combinations of flowchart illustrations may be performed by computer program instructions. Since these computer program instructions may be mounted on a processor of a general purpose computer, special purpose computer, or other programmable data processing equipment, those instructions executed through the processor of the computer or other programmable data processing equipment may be described in flow chart block (s). It creates a means to perform the functions. These computer program instructions may be stored in a computer usable or computer readable memory that can be directed to a computer or other programmable data processing equipment to implement functionality in a particular manner, and thus the computer usable or computer readable memory. It is also possible for the instructions stored in to produce an article of manufacture containing instruction means for performing the functions described in the flowchart block (s). Computer program instructions may also be mounted on a computer or other programmable data processing equipment, such that a series of operating steps may be performed on the computer or other programmable data processing equipment to create a computer-implemented process to create a computer or other programmable data. Instructions for performing the processing equipment may also provide steps for performing the functions described in the flowchart block (s).

In addition, each block may represent a portion of a module, segment, or code that includes one or more executable instructions for executing a specified logical function (s). It should also be noted that in some alternative implementations, the functions noted in the blocks may occur out of order. For example, the two blocks shown in succession may in fact be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending on the corresponding function.

In this case, the term '~ part' used in the present embodiment refers to software or a hardware component such as an FPGA or an ASIC, and '~ part' performs certain roles. However, '~' is not meant to be limited to software or hardware. '~ Portion' may be configured to be in an addressable storage medium or may be configured to play one or more processors. Thus, as an example, '~' means components such as software components, object-oriented software components, class components, and task components, and processes, functions, properties, procedures, and the like. Subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functionality provided within the components and the 'parts' may be combined into a smaller number of components and the 'parts' or further separated into additional components and the 'parts'. In addition, the components and '~' may be implemented to play one or more CPUs in the device or secure multimedia card. Also, in an embodiment, '~ part' may include one or more processors.

This technology assumes that when the RAT is heterogeneous, when two different RATs are attached to the common core system, the master node (MN) and the secondary node (SN) operate with the RRC, respectively.

In this case, it is assumed that the MN has a core network and a NAS signaling interface. 1 is a diagram showing a system to which the present invention is applied according to an embodiment of the present invention.

As shown in FIG. 1, it may be assumed that two nodes are commonly attached to an MN 110 connected to a terminal 100 by an LTE eNB, an SN 120 by an NR gNB, and a core by an EPC 130. . However, this is only an example, and the MN 110, the SN 120, and the core 130 are gNB, LTE, and NR cores, respectively, or various core and RAN nodes of heterogeneous systems such as eLTE, gNB, and NR cores. May be used.

This document contains the following shorthand:

DC: dual connectivity

MN: master node

SN: secondary node

MR: measurement report

IE: information element

RRC: radio resource control layer

MCG: master cell group

SCG: secondary cell group

RRE: RRC connection re-establishment

RB: radio bearer

PCI: physical cell ID

HO: handover

SRB: signaling radio bearer

In LTE DC, RRC may not exist in the SN. As a result, the connection through SN is performed when the radio link problem / RRC reconfiguration failure / other types of operations that require reconnection at the RRC level are performed. After executing, it is activated again as needed. For example, even if there is no problem with the link of the SN itself, if the MN link is unstable, the connection utilization of the SN side drops. In addition, interruption may proceed very long in view of data during SN link transmission.

As another problem, when the RRC message processed by the SN RRC is transmitted only to the SCG SRB, in case of an SN link using a frequency such as mmW, message transmission may not be performed well. Accordingly, a method of transmitting an SN RRC message to the MCG SRB or SCG SRB should be introduced.

In this case, if RRC is used independently of MN in SN, data communication using SN connection can be continued for a period of time until reconnection according to connection re-establishment and re-addition of SN to MN. Can be reduced. In addition, when the SN sends the SN RRC request message to the UE, a 1-bit for UL path indication may be added to the SN request message so that the UE may transmit a response RRC message by selecting one of the MCG SRB and SCG SRB.

Example 1

2 is a diagram showing Example 1. FIG.

In Embodiments 1, 2 and 3, the SRB (eg, SRB3) of the SN side should be set in advance in the UE and the SN, or the operation of setting the SRB3 before the failure of the MN should be entered in advance.

FIG. 2 illustrates an embodiment in which the MN 20 connected to the terminal 10 is an LTE eNB and the SN 30 is an NR gNB as described above with reference to FIG. 1. In step S200 and step S205, the terminal 10 may receive data from the MN 20 and the SN 30.

As in step S210, when the terminal 10 detects the MN failure, it can first stop the MCG RB. The condition for determining the MN failure by the terminal 10 may include, for example, at least one of MCG radio link failure, MCG integrity failure, MCG reconfiguration failure, and HO failure.

And the terminal 10 may release the MCG Scell (release). The terminal 10 may maintain the SCG configuration and maintain the DRB and its configuration related to the SCG. Here, the DRB associated with the SCG may refer to the SCG part of the SCG direct or split DRB or SRB or the MCG DRB or SRB. The gNB corresponding to the terminal 10 and the SN 30 may continue to transmit and receive packets through the SCG DRB. The packet may include RRC signaling and data of the UE for the SCG. Packet transmission and reception through the SN gNB 30 may continue until a new MN cell is found and reconnection is successfully completed and SCG reconfiguration is performed through the new MN cell.

In step S215, the terminal 10 may perform cell selection and perform RACH on the appropriate MN cell 40. After performing the RACH in step S220, the UE 10 may transmit a RRE request message to the newly attached MN cell 40. At this time, the RRE request message includes the C-rnti and the ID of the source cell (physical cell ID or global ID, etc.) used in the source cell, and the ID of the gNB cell 30 used as the SN (physical cell). ID to distinguish the cell such as ID or global cell ID) and the ID of the gNB. In addition, information currently used when the transmission to the SN, for example, information of the SN terminated beaerer (EPS bearer ID, ERAB ID, drb ID and QoS information corresponding to the SCG bearer (UE SN AMBR), security key, NCC, NH, security algorithm, etc. can be delivered together.

In the newly attached MN cell 40 that has received the above information, in step S225, it may be determined whether the cell has the terminal context. If the new MN cell 40 has a terminal context, the operation after step S225 shown in FIG. 1 may be performed. If not, the RRE reject message is transmitted, so that the UE switches to idle mode.

If the UE context check is successful in the new MN cell 40, in step S230, the new MN cell 40 may transmit an RRE message to the terminal 10 to transmit security and NAS related configuration information. Accordingly, the terminal 10 may perform a corresponding setting and transmit a complete message in step S235. From then on, the UE 10 and the new cell 40 of the MN may establish SRB1,2.

After the SRBs 1 and 2 are established, in step S240, the new MN cell 40 uses the cell ID and gNB id of the SN used in the RRE request message, and the gNB 30 that is the SN supporting the corresponding cell using the SCG RB information. ) Can send an SN addition request. In this case, in response to receiving the SN addition request, the SN 30 may negotiate a radio resource and transmit ack or nack to the new MN cell 40 in step S245.

In this case, in step S243, the new MN cell 40 may transmit / receive a PDU session path switch request with the core network AMF or UPF 50.

In step S250, the new MN cell 40 may deliver an RLF indication to the old MN cell 20. The forwarding of the SN addition request and the RLF indication message may be reversed. The past MN cell 20 receiving the RLF indication may transmit an SN release command to the gNB 30 which is the SN in step S255. At this time, the SN gNB 30 may stop the DL transmission. Receiving this message, the gNB can send a message to the new MN that the SN has been released.

After receiving the message that the SN has been released, the new MN 40 may deliver an RRC connection reconfiguration message to the UE, including the SCG configuration information included in the SN addition request ack message received in step S260, in step S260. have. The RRC connection reconfiguration may include a command to perform SCG configuration information and SCB related DRB release used in the past SN 30. In addition, the new MN cell 40 may directly command the terminal 10 SCG configuration based on the newly received SCG configuration. Through this, new SCG configuration information can be applied while releasing past SCG configuration information. The SCG configuration information is information obtained by the new MN 40 as a response to the content requested by the SN addition request based on the SCG / DRB information included in the RRE request. Through this, the SN 30 may know the resource request provided by the previous SN gNB 30 as much as possible, and allocate resources based on the resource request provided by the previous SN gNB 30. have.

In step S265, the UE reconnects to the cell of the corresponding SN through the RACH. In step S270, the UE may resume transmission and reception of the SN and data while transmitting an RRCConnection reconfiguration complete message to the SN cell.

In operation S275, the new MN cell 40 may transmit / receive data with the core network AMF or UPF 50.

Example 2

3 is a view showing Example 2. FIG. As described above in the first embodiment, in step S300, if the terminal 10 detects an MN failure, it may first stop the MCG RB. The terminal 10 may release the MCG Scell. In addition, the terminal 10 may maintain the SCG setting, and maintain the DRB associated with the SCG. Therefore, the operation of allowing the terminal 10 to connect the MN to the new MN cell 40 while maintaining communication with the SN cell 30 will be described.

In the case of MN failure in step S305, the terminal 10 may transmit the MCG failure information to the SN gNB 30 through the SCG SRB. In this case, the SN gNB 30 may deliver the information received from the terminal back to the MN eNB in a re-establishment required message. The MCG failure indication may include serving cell and neighbor cell measurement results (cell ID, measure value) among measurements performed in the MN cell 20. The information is delivered to the MN cell 20 in a re-establishment required message again in step S310, in which case the terminal identifier such as UE ID or C-rnti and security information used in the MN such as shortMAC-I are transmitted. Can be. The MN cell 20 that has received this message may configure information to be included in a handover request (HO) using the measurement result and the terminal identifier. In step S315, the MN 20 may transmit a Ho request to a new cell 40 of the MN determined to have the best signal state among the measurement results. The HO request may include a target cell ID to be used in the new MN 40. Or it may include multiple cell ID. If the single target cell ID is included, the MN 40 performs HO with the corresponding cell, and given the multiple cell ID, among the given cells, the new MN 40 determines the target cell. Upon receipt of the request, the new MN cell 40 may transmit ack if it is able to grant the HO of the terminal as requested in the Ho request in step S320, and nack if not. When the new MN 40 transmits a response to the HO request to the old MN 20, the new MN 40 may transmit the response to the previous MN 20 including configuration information about a resource that the new MN 40 may give. When the configuration information on the resource is delivered to the previous MN 20, in step S325, the previous MN 20 includes the UE configuration information in the corresponding HO response in the handover command message and includes the SN gNB 30. You can send In operation S330, the SN gNB 30 may deliver an RRCconnectionReconfiguration message to the terminal 10 through an SCG SRB (eg, SCG RRC). When HO cmd is delivered in step S325, the previous MN 20 may give an SN release command. The SN release command may be delivered to the RRCconnectionReconfiguration delivered to the UE 10 immediately after the SN release transmission. In this case, there may be no SN release message. In this case, after the new MN 40 receives the RRCconnectionreconfigurationComplete message after S340 separately from the HO command message, the gNB 30 transmits the HO complete message to the gNB 30 and then the SNB self-SN. Release can be performed. The terminal 10 may apply a configuration for accessing the new MN 40 with the target cell ID included in the RRCconnectionReconfiguration and the access information (rach setting, etc.) of the cell. The RRCconnectionReconfigruation may also include SCG configuration information and SN related DRB configuration information. Through this, the SN-related connection maintained after the old MN failure can be disabled.

In step S335, the terminal 10 may access the target cell of the new MN 40 through the RACH. Thereafter, in step S340, the terminal 10 may transmit the RRCconnectionReconfigurationcomplete information to the target cell. In step S350, when the MN 40 of the target cell performs the SN addition procedure and transmits the corresponding configuration information through the MCG SRB of the new MN 40 (step S355), the terminal 10 accesses the SN cell. Can be done. In addition, through Rach, the UE may transmit a connection complete and configuration complete message to the SN cell 30 (step S360).

The terminal 10 may later transmit / receive data with the SN cell 30 again.

Example 3

4 is a view showing Example 3; As described above in Embodiment 1, when the UE 10 detects an MN failure in step S400, it may first stop the MCG RB. The terminal 10 may release the MCG Scell. In addition, the terminal 10 may maintain the SCG configuration, and maintain the DRB associated with the SCG. Therefore, the operation of allowing the terminal 10 to connect the MN to the new MN cell 40 while maintaining communication with the SN cell 30 will be described. The difference from Embodiment 2 described above is that the SN addition operation is performed during the HO request-HO response with the new MN cell 40, and the SN is added to the RRCConnectionReconfiguration message transmitted from the SN cell 30 to the UE. The release and new SCG config information is included, so that the terminal 10 simultaneously performs SN release and new SN cell access.

In step S405, in case of an MN failure according to the third embodiment, when the terminal 10 transmits MCG failure information to the SN gNB 30 through the SCG SRB, the SN cell 30 returns the MN again with a re-establishment required message. May be delivered to cell 20. At this time, the MCG failure indication may include a neighbor cell measurement result (cell ID, measure value) of neighbor cells among the measurements performed in the MN cell 20. The information is transmitted back to the MN cell 20 in a re-establishment required message, in which case a terminal identifier such as UE ID or C-rnti may be included. The MN cell 20 receiving the message configures information to be included in the HO request through the measurement result and the terminal identifier, and in step S415 to the new cell 40 of the MN determined to have the best signal state among the measurement results. , Can transmit HO request. In this case, the HO request may include a target cell ID. At this time, the HO request includes PCI and SCG info / SCG DRB information of the cell used in the SN cell 30 (for example, EPS bearer ID, ERAB ID, drb ID, and QoS information corresponding to the bearer (UE SN AMBR)). This can be passed along. The new MN cell 40 receiving the HO request can transmit ack if it can approve the HO of the terminal 10 and nack if it cannot approve. Between negotiating the HO of the terminal 10 through the HO request and the HO response message, the new MN cell 40 together with the previous MN cell 20 through SN PCI (cell ID) information included in the HO request. Information on the used SN cell 30 can be obtained. Therefore, in step S420, the new MN cell 40 may request SN addition from the SN cell 30 used together with the previous MN cell 20 by transmitting an SN addition request message. At this time, by requesting the SC cell / DRB configuration information received from the HO request to the SN cell 30, if the SN cell 30 accepts this, it is possible to re-assign radio resources for guaranteeing the QoS level previously received in the SN cell. Through this, in step S425, when the SN cell 30 receives the new SCG config, the SN cell 30 may be loaded together with the SN addition ack and transferred to the new MN cell 40. In operation S430, the new MN cell 40 may transmit the HO response to the previous MN cell 20 including the SCG config.

When the new MN cell 40 transmits the HO response to the HO request to the old MN cell 20, the new MN cell 40 may include the configuration information on the resources that the new MN cell 40 can give. When the information is transmitted to the previous MN cell 20, in step S435, the previous MN cell 20 loads the UE configuration information in the corresponding HO response in the HO cmd message and the SN gNB 20 currently communicating with the terminal 10. You can also send an SN release command at the same time. In operation S440, the gNB 30, which is an SN cell, may transmit an RRCconnectionReconfiguration to the terminal 10 through the SCG SRB. The terminal 10 applies a setting for accessing the new MN cell 40 with the MN target cell ID included in the RRCconnectionReconfiguration and the access information (rach setting, etc.) of the cell, and applies the newly received SN related SCG config. SN radio information can be set by applying. In this case, the terminal 10 may apply the configuration information of the newly received SCG config by removing the SN-related DRB configuration information and SCG configuration information received from the previous SN cell 30. In operation S445, the terminal 10 may perform a RACH to access the target cell of the new MN cell 40. In operation S450, the terminal 10 may transmit the RRCconnectionReconfigurationcomplete information to the target cell of the new MN 40.

Meanwhile, in step S455, the new MN cell 40 may complete the PDC session modification with the core network 50.

Then, in step S460, the terminal 10 may perform a RACH with the SN cell 30 through the access information in the new SCG config. In this case, the RACH with the SN cell 30 may be omitted. Thereafter, the terminal 10 may transmit and receive data with the SN cell 30.

Example 4

According to another embodiment of the present invention, in a multi-RAT dual connectivity including EN-DC, an SN RRC message may be delivered using SCG SRB in addition to MCG SRB. In the case of an RRC message generated in SN RRC, if the message is a request type message requesting a response, the UL path of the SN RRC response message corresponding to the corresponding SN RRC request message may be indicated. Hereinafter, according to another embodiment of the present disclosure, a method of transmitting an SN RRC message by a terminal is disclosed. To indicate the UL path, 1 bit for the UL path indication may be included in the SN RRC request message. The bit may indicate whether the corresponding SN RRC response message is transmitted to the SCG SRB or the MCG SRB.

5 is a diagram showing Embodiment 4 of the present invention.

In step S500, the UE may receive an SN RRC request message. The UE may determine whether the SN RRC request message is received and the UL path indication bit included in the SN RRC request message, and encapsulates the MN RRC message to send to the MCG SRB or the SCG SRB.

For example, in step S510, the UE may check whether the SN RRC request message is delivered by being encapsulated in the MN. Based on the check result, when the SN RRC request message is delivered by being encapsulated in the MN, in step S520, the UE may check whether the SN RRC response UL path indication bit is indicated as SCG SRB. If the SN RRC response UL path indication bit is indicated by the SCG SRB, in step S523, the UE may transmit the MN RRC response message to the MCG SRB and the SN RRC response message to the SCG SRB. On the other hand, when the SN RRC response UL path indication bit is not indicated by the SCG SRB, that is, when the SN RRC response UL path indication bit is indicated by the MCG SRB, in step S525, the UE transmits the MN RRC response message to the MCG SRB. In addition, the SN RRC response message may be delivered as an encapsulate in the MN RRC response message.

On the other hand, when the SN RRC request message is not encapsulated in the MN and delivered in step S510, that is, when directly delivered through the SCG SRB, in step S530, the UE is indicated by the SN RRC response UL path indication bit as SCG SRB You can check whether there is. As a result of the check, when the SN RRC response UL path indication bit is indicated by the SCG SRB, in step S533, the UE may transmit the SN RRC response message to the SCG SRB. On the other hand, when the SN RRC response UL path indication bit is not indicated by the SCG SRB, in step S535, the UE may transmit the MN RRC unidirectional message to the MCG SRB. In addition, the UE may transmit the SN RRC response message by encapsulating the MN RRC unidirectional message.

In summary, for the received SN RRC request message,

1. If the MN RRC message is encapsulated and delivered, and the MN RRC message is removed and only the SN message is seen, if the UL path is SCG SRB, the UE delivers the MN RRC response message to the MCG SRB, and a separate SN RRC response message. Can be created and delivered via SCG SRB. In this case, the MN RRC response message may be omitted.

2. If the MN RRC message is encapsulated and delivered and the MN RRC message is removed and only the SN message is seen, if the UL path is MCG SRB, the UE creates an MN RRC response message and the SN RRC response to the MN RRC response message. The message may be included and delivered through the MCG SRB. The MN receiving the message may separate only the SN RRC response message and deliver it to the SN as an inter node message.

3. If the transmission is directly through the SCG SRB, and if the UL path is SCG SRB, the UE can directly transmit the SN RRC response message to the SN through the SCG SRB.

When the MN receives the RRC message from the SN, the UE sends an encapsulation to its MN RRC message, and when the MN receives the MN RRC response message from the UE, the MN checks whether the SN message is encapsulated therein. Delivers SN messages to the Xn interface, if not present.

4. If it is directly transmitted through the SCG SRB, and the UL path is MCG SRB, the UE may make an MN RRC unidirectional message and include the SN RRC response message in the MN RRC unidirectional message to transmit it through the MCG SRB. The MN receiving the message may separate only the SN RRC response message and deliver it to the SN as an inter node message.

6 is a sequence diagram illustrating case 1. First, in step S600, while the SN cell 30 transmits an SN RRC request message to the MN cell 20, the SN RRC response UL path indication bit may be indicated and transmitted as an SCG SRB. In operation S610, the MN cell 20 may encapsulate and transmit an SN RRC request message to the MN RRC request message to the terminal 10. The terminal 10 may check the SN RRC response UL path indication bit as described above. As a result of the check, when the SN RRC response UL path indication bit is indicated as the SCG SRB, the terminal 10 may determine to transmit the SN RRC response message using the SCG SRB in step S620. Specifically, in step S630, the terminal 10 may transmit an MN RRC response message to the MCG SRB, and in step S640, the terminal 10 may transmit an SN RRC response message to the SCG SRB.

On the other hand, Figure 7 is a sequence diagram showing a case 2. As in the embodiment described with reference to FIG. 6, in step S700, the SN cell 30 may transmit an SN RRC request message to the MN cell 20. In the embodiment shown in FIG. 7, the SN RRC response UL path indication bit may be indicated by the MCG SRB and transmitted. In operation S710, the MN cell 20 may encapsulate and transmit an SN RRC request message to the MN RRC request message to the terminal 10. The terminal 10 may check the SN RRC response UL path indication bit. As a result of confirmation, when the SN RRC response UL path indication bit is indicated as MCG SRB, the UE 10 may determine to transmit an SN RRC response message using the MCG SRB in step S720. In detail, in step S730, the terminal 10 may transmit an MN RRC response message to the MCG SRB. In step S740, the MN cell 20 may separate only the SN RRC response message and deliver it to the SN as an inter node message.

8 is a sequence diagram showing case 3. FIG. In the embodiment of FIG. 8, first, in step S800, the terminal 10 may receive an SN RRC request message from the SN cell 30 through an SCG SRB. In this case, if the UL path is SCG SRB in the SN RRC request message, the UE 10 may determine to use the SCG SRB in step S810. In operation S820, the terminal 10 may directly transmit an SN RRC response message to the SN through the SCG SRB.

9 is a sequence diagram showing case 4. FIG. In the embodiment of FIG. 9, first, in step S900, the terminal 10 may receive an SN RRC request message from the SN cell 30 through an SCG SRB. In this case, if the UL path is the MCG SRB in the SN RRC request message, the UE 10 may determine to use the MCG SRB in step S9610. Accordingly, in step S920, the terminal 10 may make an MN RRC unidirectional message and include the SN RRC response message in the MN RRC unidirectional message to transmit the MCR SRB. In addition, the MN cell 20 receiving the message may separate only the SN RRC response message, and may transmit the message to the SN cell 30 as an inter node message in step S930.

Example 5

According to another embodiment of the present invention, the SN Measurement report may be set by measConfig included in the SN RRC connection reconfiguration message. In this case, in addition to the UL path indication bit of the SN RRCConnectionReconfigurationComplete message, which is a response message of the SN RRCConnectionReconfiguration message, a measurement report message set in measConfig IE is later used when the corresponding event occurs. There may be a 1 bit indication. If the indication is indicated through the SN RRC message, as described above in the fourth embodiment, the UE can transmit the SN RRCConnectionReconfigurationComplete, which is a response message of the SN RRCConnectionReconfiguration message, by viewing UL path indication information and selecting one from SCG / MCG SRB. have. At the same time, the terminal reports the MR UL path indication bit in the measConfig IE and may transmit the measurement report (MR) to the corresponding UL path when an event occurs. For example, when the MR is set to be transmitted to the SCG SRB, the terminal may be directly transmitted to the SCG SRB. If the MR is set to be transmitted to the MCG SRB, the terminal may be transmitted to the MN by being included in an MN RRC response or a one-way message. And MN can deliver only the received MR to the SN.

In detail, FIG. 10 is a sequence diagram illustrating an embodiment in which an SN RRCConnectionReconfigurationComplete is transmitted to an SCG SRB and an MR is also transmitted to the SCG SRB.

First, in step S1000, the SN cell 30 sets both the UL path indication bit for the RRCConnectionReconfigurationComplete and the MR UL path indication bit of the measConfig IE to indicate the SCG SRB to the MN cell 20 to transmit the SN RRC connection reconfiguration message. Can be. In operation S1010, the MN cell 20 may encapsulate and transmit an SN RRC request message to the MN RRC request message to the terminal 10. The terminal 10 may check the UL path indication bit for the RRCConnectionReconfigurationComplete and the MR UL path indication bit of the measConfig IE.

As a result of the check, when the indication bits indicate the SCG SRB, the terminal 10 may determine to transmit the SN RRCConnectionReconfigurationComplete message and the MR using the SCG SRB in step S1020.

Accordingly, the terminal 10 transmits an MN RRC response message to the MN cell 20 in step S1030. In steps S1040 and S1050, the terminal 10 may transmit an SN RRCConnectionReconfigurationComplete message and an MR using the SCG SRB. have. 11 is a sequence diagram illustrating an embodiment in which an SN RRCConnectionReconfigurationComplete is transmitted to an MCG SRB and an MR is also transmitted to an SCG SRB. First, in step S1100, the SN cell 30 sets the UL path indication bit for the RRCConnectionReconfigurationComplete to the MN cell 20 to indicate the MCG SRB and the MR UL path indication bit of the measConfig IE to indicate the SCG SRB. You can send a connection reconfiguration message. In operation S1110, the MN cell 20 may transmit an encapsulated SN RRC request message to the MN RRC request message to the terminal 10. The terminal 10 may check the UL path indication bit for the RRCConnectionReconfigurationComplete and the MR UL path indication bit of the measConfig IE.

Based on the confirmation result, in step S1120, the terminal 10 may determine a path to transmit the RRC message.

In detail, in step S1130, the terminal 10 may transmit an MN RRC response message to the MN cell 20. In this case, an SN RRCConnectionReconfigurationComplete message may be encapsulated in the MN RRC response message and transmitted together with the MN cell 20. Accordingly, in step S1140, the MN cell 20 may transmit the SN RRCConnectionReconfigurationComplete message to the SN cell 30. In operation S1150, the terminal 10 may transmit the MR to the SN cell 30 using the SCG SRB. 12 is a sequence diagram illustrating an embodiment in which an SN RRCConnectionReconfigurationComplete is transmitted to an SCG SRB and an MR to an MCG SRB. First, in step S1200, the SN cell 30 is configured to indicate to the MN cell 20 the UL path indication bit for the RRCConnectionReconfigurationComplete indicates the SCG SRB, and the MR UL path indication bit of the measConfig IE indicates the MCG SRB. You can send a connection reconfiguration message. In operation S1210, the MN cell 20 may encapsulate and transmit an SN RRC request message to the MN RRC request message to the terminal 10. The terminal 10 may check the UL path indication bit for the RRCConnectionReconfigurationComplete and the MR UL path indication bit of the measConfig IE.

Based on the confirmation result, in step S1220, the terminal 10 may determine a path to transmit the RRC message.

In detail, in step S1230, the terminal 10 may transmit an MN RRC response message to the MN cell 20. In operation S1240, the terminal 10 may transmit the SN RRCConnectionReconfigurationComplete message to the SN cell 30 using an SCG SRB. In operation S1250, the terminal 10 may transmit an MN RRC response message including the MR to the MN cell 20 using the MCG SRB. The MN cell 20 may separate the MR and transmit the same to the SN cell 30. FIG. 13 is a sequence diagram illustrating an embodiment in which an SN RRCConnectionReconfigurationComplete is transmitted to an MCG SRB and an MR is also transmitted to the MCG SRB. First, in step S1300, the SN cell 30 sets both the UL path indication bit for the RRCConnectionReconfigurationComplete and the MR UL path indication bit of the measConfig IE to indicate the MCG SRB to the MN cell 20 to transmit the SN RRC connection reconfiguration message. Can be. In step S1310, the MN cell 20 may transmit an SN RRC request message to the terminal 10 by encapsulating the MN RRC request message. The terminal 10 may check the UL path indication bit for the RRCConnectionReconfigurationComplete and the MR UL path indication bit of the measConfig IE.

As a result of the check, when the indication bits indicate the MCG SRB, the terminal 10 may determine to transmit the SN RRCConnectionReconfigurationComplete message and the MR using the MCG SRB in step S1320.

Therefore, the terminal 10 may transmit an MN RRC response message to the MN cell 20 in step S1330. In this case, an SN RRCConnectionReconfigurationComplete message may be encapsulated in the MN RRC response message and transmitted together with the MN cell 20. Accordingly, in step S1340, the MN cell 20 may transmit the SN RRCConnectionReconfigurationComplete message to the SN cell 30.

In operation S1350, the terminal 10 may transmit an MN RRC response message including the MR to the MN cell 20 using the MCG SRB. In step S1360, the MN cell 20 may separate the MR and transmit the MR to the SN cell 30. FIG. 14 is included in each RRCconnectionReconfiguration message of a plurality of separate measConfig and transmitted. FIG. 11 is a sequence diagram illustrating a case where MR UL paths are set differently. At this time, the MR set in each measConfig can be independently transmitted to each set UL path.

Specifically, in step S1400, the SN cell 30 sets both the UL path indication bit for the RRCConnectionReconfigurationComplete and the MR UL path indication bit of the first measConfig IE to indicate the SCG SRB to the MN cell 20 so as to indicate the SN RRC connection reconfiguration message. Can be transmitted. In operation S1405, the MN cell 20 may transmit an SN RRC reconfiguration message to the terminal 10 by encapsulating the MN RRC request message. The terminal 10 may check the UL path indication bit for the RRCConnectionReconfigurationComplete and the MR UL path indication bit of the measConfig IE.

As a result of the check, when the indication bits indicate the SCG SRB, the terminal 10 may determine to transmit an SN RRCConnectionReconfigurationComplete message and an MR using the SCG SRB in step S1410.

Accordingly, the terminal 10 transmits an MN RRC response message to the MN cell 20 in step S1415. In steps S1420 and S1425, the terminal 10 transmits an SN RRCConnectionReconfigurationComplete message and a first MR using the SCG SRB. Each can be transmitted.

Meanwhile, in step S1430, the SN cell 30 sets the UL path indication bit for the RRCConnectionReconfigurationComplete to the MN cell 20 to indicate the SCG SRB and the MR UL path indication bit of the measConfig IE to indicate the MCG SRB. You can send a connection reconfiguration message. In operation S1435, the MN cell 20 may encapsulate and transmit an SN RRC request message to the MN RRC request message to the terminal 10. The terminal 10 may check the UL path indication bit for the RRCConnectionReconfigurationComplete and the MR UL path indication bit of the measConfig IE.

Based on the confirmation result, in step S1440, the terminal 10 may determine a path to transmit the RRC message.

In detail, in step S1445, the terminal 10 may transmit an MN RRC response message to the MN cell 20. In operation S1450, the terminal 10 may transmit the SN RRCConnectionReconfigurationComplete message to the SN cell 30 using an SCG SRB. In operation S1455, the terminal 10 may transmit an MN RRC response message including the second MR to the MN cell 20 using the MCG SRB. In step S1460, the MN cell 20 may separate and transmit the second MR to the SN cell 30.

Example 6

According to another embodiment of the present invention, the UL path of the MR MR for SN may be set per measConfig IE included in the RRCConnectionReconfiguration, but may also be set for each measId in measConfig. In this case, 1 bit for UL path selection for SN RRCConnectionReconfigurationComplete and MR UL path indication bits for each measID of measConfig IE may be separately included and transferred in the SN RRCConnectionReconfiguration message. The UE reports the SN RRCConnectionReconfiguration message, reports the MR UL path indication for each measID included in the SN RRCConnectionReconfiguration message, and transmits the corresponding MR to the configured UL path when an event for each measID occurs.

Specifically, Embodiment 6 will be described based on FIG. 15. First, in step S1500, the SN cell 30 sets the UL path indication bit for the RRCConnectionReconfigurationComplete to the MN cell 20 to indicate the SCG SRB, and in the measConfig IE, the first measID sets the MR UL path indication bit to the SCG SRB, The second measID may set the MR UL path indication bit to the MCG SRB to transmit an SN RRC connection reconfiguration message. In operation S1510, the MN cell 20 may encapsulate and transmit an SN RRC reconfiguration message to the MN RRC request message to the terminal 10. The terminal 10 may check the UL path indication bit for the RRCConnectionReconfigurationComplete and the MR UL path indication bits for the first and second measIDs of the measConfig IE. Based on the confirmation result, in step S1520, the terminal 10 may determine to transmit an SN RRCConnectionReconfigurationComplete message and an MR for the first measID using the SCG SRB. The terminal 10 may determine to transmit the MR for the second measID using the MCG SRB.

Accordingly, the terminal 10 transmits an MN RRC response message to the MN cell 20 in step S1530. In steps S1540 and S1550, the terminal 10 transmits an SN RRCConnectionReconfigurationComplete message and a first MR using an SCG SRB. Each can be transmitted.

In operation S1560, the terminal 10 may transmit an MN RRC response message including the second MR to the MN cell 20 using the MCG SRB. In step S1570, the MN cell 20 may separate the second MR and transmit it to the SN cell 30.

For example, when the carrier frequency of the SN cell is mmW band, the SN cell may always set the MR UL path to MCG SRB. Or MR UL, if it is determined that the link quality is very low based on the link status of the SN cell (the average level of RSRP feedback from the terminal or directly measured by the SRS, or the average number of RLC retransmissions or HARQ retransmissions). The path may be set to MCG SRB.

The SN RRC request message may be any type of message in which the UE sends a one-time response corresponding to the UE in SN RRC, and the SN RRC response message refers to a response message transmitted by the UE. For example, the following is an example of a request-response message.

CounterCheck CounterCheckResponse

RRCConnectionReconfiguration RRCConnectionReconfigurationComplete

RRCConnectionResume RRCConnectionResumeComplete

SecurityModeCommand SecurityModeComplete, SecurityModeFailure

UECapabilityEnquiry UECapabilityInformation

UEInformationRequest UEInformationResponse

In addition, there may be a message sent by the SN RRC one time to the DL or a message sent by the terminal to the UL one time. The one-time message sent to the DL can be directly sent by the SN RRC by selecting the MCG SRB or the SCG SRB, and each UL one-time SN RRC message has a predetermined SRB for the default SN so that the one-time message can be transmitted to the default SRB. The default SRB may be selected from MCG SRB and SCG SRB and transmitted to the UE as system information.

According to another embodiment of the present invention, an operation required for the SCG change indication or a use case requiring the operation may be displayed and transmitted to the SN or the MN.

Since NR PDCP can be used in the LTE user plane, in relation to PDCP version change, PDCP anchor point change, security key refresh, etc. of bearers used in SCG, existing synchronous reconfiguration (for example, when the UE is MAC, In the case where RLC reset and PDCP re-establishment for SCG and RACH to target SCG) are collectively performed, each layer 2 stack can be partially reset. In this regard, through the SCG change message, the partial synchronous reconfiguration operation required for the SCG change IE may be displayed or the use case may be displayed so that the SN may prepare for the operation and reduce latency.

16A to 16C illustrate an embodiment of an MN initiated SCG change.

First, as in step S1600, the MN 20 may deliver a SCG change indication in an SN modification request message, while delivering the necessary operation of synchronous reconfiguration to the SN 30. In this case, the necessary operation may be as follows. security key refresh, reconfiguration, RACH, RACH and MAC reset, RACH and MAC reset and RLC reset, RACH and MAC reset and RLC reset and PDCP re-establishment. When the SN 30 receives the message, the SN 30 performs an operation for the necessary operation. For example, if the general reconfiguration is not a reset of the sub-layer of the L2 stack, the reconfiguration is performed, and if the RACH is displayed in the message, the random access preamble transmission of the corresponding UE is monitored. Can be.

As shown in FIG. 16A, when RACH and MAC reset is displayed as a necessary operation of synchronous reconfiguration, the SN 30 may reset the MAC belonging to the corresponding UE. The SN 30 may wait for the RACH operation of the terminal 10. In step S1605, the SN 30 may transmit the SN modification ack message to the MN 20, including the SCG setting for setting the RACH and the MAC reset. In operation S1610, the MN 20 may transmit the received setting to the terminal 10. Accordingly, the terminal 10 may reset the MAC in step S1615. In operation S1620, the UE 10 may transmit an RACH to the SN 30.

Meanwhile, according to another embodiment, when the necessary operations of synchronous reconfiguration are RACH, MAC, and RLC reset, the SN 30 may reset all RLC entities belonging to the corresponding UE 10 and may also reset the MAC. . The SN 30 may wait for the RA of the terminal 10. In detail, as shown in FIG. 16B, in step S1625, the SN 30 may transmit an SN modification ack message to the MN 20, including an SCG setting for setting RACH, MAC, and RLC reset. In operation S1630, the MN 20 may transmit the received setting to the terminal 10. Accordingly, the terminal 10 may reset the MAC and RLC in step S1635. In operation S1640, the terminal 10 may transmit a RACH to the SN 30.

According to another embodiment, when the necessary operation of synchronous reconfiguration is RACH and MAC / RLC reset and PDCP re-establishment, the SN 30 re-establishes the PDCP of the terminal 10 and then performs RLC and MAC. You can reset it. The SN 30 may wait for the RA of the terminal 10. Specifically, as shown in FIG. 16C, in step S1645, the SN 30 transmits an SN modification ack message to the MN 20, including an SCG setting for setting RACH and MAC / RLC reset and PDCP re-establishment. Can transmit In operation S1650, the MN 20 may transmit the received setting to the terminal 10. Accordingly, the terminal 10 may reset the MAC and RLC in step S1655. The terminal 10 may perform PDCP re-establishment. In addition, in step S1660, the terminal 10 may transmit a RACH to the SN (30).

In each of the embodiments illustrated in FIGS. 16A to 16C, when the MN 20 indicates an operation required for the SCG change indication IE in the SN modification request message, the SN 30 confirms the displayed operation and confirms the required operation. And it can create a reconfiguration message required by the terminal. The message is delivered to the MN 20 as a container, and when the MN 20 reconfigures the terminal 10, the message may be delivered by the SN 30 to allow the terminal 10 to perform a necessary operation. . In summary, the terminal 10 shown in FIG. 16A is MAC reset and RACH, or the terminal 10 shown in FIG. 16B is MAC / RLC reset and RACH, or the terminal 10 shown in FIG. 16C is MAC / RLC. An embodiment of performing reset, PDCP re-establishment, and RACH is shown. In addition to this operation, the SCG change indication indication and the UE operation, which simply perform reconfiguration, may also be performed. For example, reconfiguration is reconfiguration without MAC reset, RACH is RACH, RACH and MAC reset is reconfiguration with MAC reset, RACH and MAC / RLC reset is traditional handover but without PDCP re-establishment, RACH and MAC / RLC / PDCP reset / re -establish can be traditional HO

Meanwhile, FIGS. 17A to 17C illustrate an embodiment of SN initiated SCG change. Specifically, in step S1700, the SN 30 may indicate to the MN 20 an operation required for the SCG change indication IE in the SN modification required message. In step S1710, the MN 20 receiving the message may generate an SN modification request and deliver it back to the SN 30, including the necessary operation received from the SN 30 in the SCG change indication IE of the SN modification request. have. Specifically, when the SN 30 recognizes the occurrence of one of the above-described embodiments, it transmits the SCG change indication to the MN 20 in the SN modification required message, and delivers the necessary operation of the synchronous reconfiguration to the MN 20. Can be. In this case, the necessary operation may be as follows. reconfiguration, RACH, RACH and MAC reset, RACH and MAC reset and RLC reset, RACH and MAC reset and RLC reset and PDCP re-establishment.

The MN 20 may generate an SN modification request. The MN 20 may forward back to the SN 30, including the necessary actions received from the SN 30 in the SCG change indication IE of the SN modification request.

When the SN 30 receives the SN modification request message, the SN 30 performs an operation performed for the necessary operation. For example, if the general reconfiguration is not a reset of the sub-layer of the L2 stack, the reconfiguration is performed, and if the RACH is displayed in the message, the random access preamble transmission of the corresponding UE can be monitored without performing any other operation. .

Specifically, as shown in 17a, when RACH and MAC reset are displayed as a necessary operation of synchronous reconfiguration, the SN 30 may reset the MAC belonging to the corresponding terminal. The SN 30 may wait for the RACH operation of the terminal 10. In step S1715, the SN 30 may transmit the SN modification ack message to the MN 20, including the SCG setting for setting the RACH and the MAC reset. In operation S1720, the MN 20 may transmit the received setting to the terminal 10. Accordingly, the terminal 10 may reset the MAC in step S1725. In operation S1730, the terminal 10 may transmit a RACH to the SN 30.

Meanwhile, according to another embodiment, when the necessary operations of synchronous reconfiguration are RACH, MAC, and RLC reset, the SN 30 may reset all RLC entities belonging to the corresponding UE 10 and may also reset the MAC. . The SN 30 may wait for the RA of the terminal 10. In detail, as illustrated in FIG. 17B, in step S1735, the SN 30 may transmit an SN modification ack message to the MN 20, including an SCG setting for setting RACH, MAC, and RLC reset. In operation S1740, the MN 20 may transmit the received setting to the terminal 10. Accordingly, the terminal 10 may reset the MAC and RLC in step S1745. In operation S1750, the terminal 10 may transmit a RACH to the SN 30.

According to another embodiment, when the necessary operation of synchronous reconfiguration is RACH and MAC / RLC reset and PDCP re-establishment, the SN 30 re-establishes the PDCP of the terminal 10 and then performs RLC and MAC. You can reset it. The SN 30 may wait for the RA of the terminal 10. In detail, as shown in FIG. 17C, in step S1755, the SN 30 transmits an SN modification ack message to the MN 20, including an SCG setting for setting RACH and MAC / RLC reset and PDCP re-establishment. Can transmit In operation S1760, the MN 20 may transmit the received setting to the terminal 10. Accordingly, the terminal 10 may reset the MAC and RLC in step S1765. The terminal 10 may perform PDCP re-establishment. In addition, in step S1770, the terminal 10 may transmit a RACH to the SN (30).

As described with reference to FIGS. 17A through 17C, the MN 20 receiving the SN modification required message forwards the SN modification request to the SN 30 that has sent the SN modification required, so that the SN 30 performs the operation. Can be ordered.

In this case, the necessary operations may be replaced by the name of the situation in which the operation is required, not the operation itself. For example, reconfiguration is reconfiguration without MAC reset, RACH is RACH, RACH and MAC reset is reconfiguration with MAC reset, RACH and MAC / RLC reset is traditional handover but without PDCP re-establishment, RACH and MAC / RLC / PDCP reset / re -establish can be traditional HO

18 is a diagram illustrating a structure of a terminal according to an embodiment of the present invention.

Referring to FIG. 18, the terminal may include a transceiver 1810, a controller 1820, and a storage 1830. In the present invention, the controller may be defined as a circuit or application specific integrated circuit or at least one processor.

The transceiver 1810 may exchange a signal with another network entity. The transceiver 1810 may receive system information from, for example, a base station, and may receive a synchronization signal or a reference signal.

The controller 1820 may control the overall operation of the terminal according to the embodiment proposed by the present invention.

For example, the controller 1820, if the connection with the first master node (MN) of the terminal is released, RRC connection reestablishment request (connection) including the identifier information for the secondary node (secondary node, SN) (connection) Send a re-establishment request message to a second master node (MN), and when the second MN includes context information for the terminal, receives an RRC connection reestablishment message from the second MN. The transceiver 1810 may be controlled to control the transmission / reception unit 1810.

In this case, an SN addition request message may be transmitted to the SN by the second MN based on the identifier information of the SN.

The RRC connection reestablishment request message may further include bearer information for the SN.

The SN may be characterized by including an RRC layer (radio resource control layer).

The storage unit 1830 may store at least one of information transmitted and received through the transceiver 1810 and information generated through the controller 1820.

19 is a diagram illustrating a structure of a base station according to an embodiment of the present invention. The base station may be an eNB of LTE system (including MeNB, SeNB) or a gNB of NR system.

Referring to FIG. 19, the base station may include a transceiver 1910, a controller 1920, and a storage 1930. In the present invention, the controller 1920 may be defined as a circuit or application specific integrated circuit or at least one processor.

The transceiver 1910 may exchange a signal with another network entity. The transceiver 1910 may transmit system information to the terminal, for example, and may transmit a synchronization signal or a reference signal.

The controller 1920 may control the overall operation of the base station according to the embodiment proposed by the present invention. For example, when the base station is the second MN, the controller 1920 includes identifier information on the secondary node (SN) from the terminal disconnected from the first master node (MN). When receiving the RRC connection re-establishment request message, and includes the context information for the terminal, the transceiver 1910 can be controlled to transmit the RRC connection reestablishment message to the terminal. have.

The controller 1920 may control the transceiver 1910 to transmit an SN addition request message to the SN based on the identifier information of the SN.

In this case, the RRC connection reestablishment request message may further include bearer information for the SN.

In addition, the SN may include an RRC layer (radio resource control layer).

The storage unit 1930 may store at least one of information transmitted and received through the transceiver 1910 and information generated through the controller 1920.

In addition, the present specification and drawings disclose preferred embodiments of the present invention, although specific terms are used, these are merely used in a general sense to easily explain the technical contents of the present invention and to help the understanding of the present invention. It is not intended to limit the scope of the invention. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention can be carried out in addition to the embodiments disclosed herein.

Claims (15)

1. In a control method of a terminal in a wireless communication system supporting dual connectivity,

   When the connection with the first master node (MN) is released, the second master node sends an RRC connection re-establishment request message including identifier information about the secondary node (SN). transmitting to (master node, MN); And

   Receiving the RRC connection reestablishment message from the second MN when the second MN includes context information about the terminal; How to include.
2. The method of claim 1,

   And by the second MN, an SN addition request message is transmitted to the SN based on the identifier information of the SN.
3. The method of claim 1,

   The RRC connection reestablishment request message,

   Further comprising bearer information for the SN.
4. The method of claim 1,

   The SN comprises a radio resource control layer (RRC).
5. In a terminal in a wireless communication system supporting dual connectivity,

   Transmitting and receiving unit for transmitting and receiving a signal; And

   When the connection with the first master node (MN) is released, the second master node sends an RRC connection re-establishment request message including identifier information about the secondary node (SN). a control unit for transmitting to a master node (MN) and controlling the transceiver to receive an RRC connection reestablishment message from the second MN when the second MN includes context information about the terminal; Terminal comprising a.
6. The method of claim 5,

   The terminal is characterized in that by the second MN, the SN addition request message is transmitted to the SN based on the identifier information for the SN.
7. The method of claim 5,

   The RRC connection reestablishment request message,

   The terminal further comprises bearer information for the SN.
8. The method of claim 5,

   The SN is characterized in that it comprises an RRC layer (radio resource control layer).
9. In a control method of a master node (MN) in a wireless communication system,

   Receiving an RRC connection re-establishment request message including identifier information on a secondary node (SN) from a terminal disconnected from another master node (MN); And

   If it includes context information for the terminal, transmitting an RRC connection reestablishment message to the terminal; How to include.
10. The method of claim 9,

    Transmitting an SN addition request message to the SN based on the identifier information of the SN; Method further comprising a.
11. The method of claim 9,

    The RRC connection reestablishment request message,

    Further includes bearer information for the SN,

    The SN comprises a radio resource control layer (RRC).
12. In a master node (MN) in a wireless communication system,

    Transmitting and receiving unit for transmitting and receiving a signal; And

    Receiving an RRC connection re-establishment request message including identifier information for a secondary node (SN) from a terminal disconnected from another master node (MN), A control unit for controlling the transceiver to transmit an RRC connection reestablishment message to the terminal when it includes context information about the terminal; MN comprising a.
13. The method of claim 12,

    The control unit,

    MN, characterized in that for controlling the transceiver to send an SN addition request message to the SN based on the identifier information for the SN.
14. The method of claim 12,

    The RRC connection reestablishment request message,

    MN further comprises bearer information for the SN.
15. The method of claim 12,

    The SN includes an RRC layer (radio resource control layer).

Images