CN117716732A

CN117716732A - Method and apparatus for updating configuration of conditional PSCell change in next generation mobile communication system

Info

Publication number: CN117716732A
Application number: CN202280053112.6A
Authority: CN
Inventors: 黄�俊; 阿尼尔·阿基瓦尔
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2021-08-05
Filing date: 2022-08-04
Publication date: 2024-03-15

Abstract

The present disclosure relates to: a communication technology and system for merging IoT technology with a 5G communication system to support data transmission rates higher than 4G systems. The present disclosure can be applied to smart services (for example, smart homes, smart buildings, smart cities, smart cars or connected cars, health care, digital education, retail enterprises, security and safety-related services, etc.) based on 5G communication technology and IoT related technologies. . The present disclosure provides a method and device for updating the configuration of a conditional PSCell change.

Description

Method and apparatus for updating configuration of conditional PSCell change in next generation mobile communication system

Technical Field

The present disclosure relates to a next generation mobile communication system or a wireless communication system. In particular, the present disclosure relates to an operation of updating a configuration of a source primary and Secondary Cell Group (SCG) cell (PSCell) change in a case of the configuration change of the PSCell in a conditional mobility operation of a terminal.

Background

In order to meet the increasing demand for wireless data services since the deployment of 4G communication systems, efforts have been made to develop an improved 5G or quasi 5G communication system. Therefore, a 5G or quasi 5G communication system is also referred to as a "super 4G network" or a "LTE-after-system".

A 5G communication system is considered to be implemented in a higher frequency (millimeter wave) band (e.g., 60GHz band) in order to achieve higher data rates. In order to reduce propagation loss of radio waves and increase transmission distance, beamforming, massive Multiple Input Multiple Output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, massive antenna techniques are discussed in 5G communication systems.

In addition, in the 5G communication system, development of system network improvement is underway based on advanced small cells, cloud Radio Access Networks (RANs), ultra dense networks, device-to-device (D2D) communication, wireless backhaul, mobile networks, cooperative communication, coordinated multipoint (CoMP), reception-side interference cancellation, and the like. In 5G systems, hybrid FSK and QAM modulation (FQAM) as Advanced Code Modulation (ACM) and Sliding Window Superposition Coding (SWSC) have been developed, as well as Filter Bank Multicarrier (FBMC), non-orthogonal multiple access (NOMA) and Sparse Code Multiple Access (SCMA) as advanced access techniques.

The internet, which is a human-centric connectivity network in which humans generate and consume information, now evolves into the internet of things (IoT) in which distributed entities such as things exchange and process information without human intervention. Internet of everything (IoE), which is a combination of IoT technology and big data processing technology through connection with cloud servers, has emerged. As IoT implementations require technical elements such as "sensing technology," "wired/wireless communication and network infrastructure," "service interface technology," and "security technology," sensor networks, machine-to-machine (M2M) communications, machine Type Communications (MTC), etc. have recently been investigated. Such IoT environments may provide intelligent internet technology services that create new value for human life by collecting and analyzing data generated between connections. IoT may be applied in a variety of fields including smart homes, smart buildings, smart cities, smart cars or networked cars, smart grids, healthcare, smart appliances, and advanced medical services through fusion and combination between existing Information Technology (IT) and various industrial applications.

Accordingly, various efforts have been made to apply 5G communication systems to IoT networks. For example, techniques such as sensor networks, machine Type Communications (MTC), and machine-to-machine (M2M) communications may be implemented by beamforming, MIMO, and array antennas. By applying cloud Radio Access Networks (RANs) as described above, big data processing techniques may also be considered as examples of convergence between 5G techniques and IoT techniques.

Meanwhile, with the development of mobile communication systems, there is an increasing need for a method of efficiently updating a conditional cell change configuration.

Disclosure of Invention

Technical problem

Technical objects to be achieved by the embodiments of the present disclosure are as follows. In the case of a change in inter-Secondary Node (SN) condition PSCell, if the configuration of the source PSCell is changed in the case that the terminal has been given a conditional PSCell change configuration, the corresponding configuration change is reflected so that the configurations of the current Master Cell Group (MCG) and Master Node (MN) and the configuration of the target PSCell must all be able to be changed.

Currently, there are only two signaling systems between the source SN, MN and the target SN node: a procedure for configuring inter-SN Conditions PSCell Changes (CPCs) and a procedure for updating the configuration of source SNs. In these procedures, inter-SN CPC configuration does not allow changes in MN/MCG configuration, and source SN configuration update procedures do not allow updating of CPC configuration of target SN. Thus, there must be a procedure that allows both updates to enable updating of the MN/MCG configuration with respect to changes in source SN configuration between SNs and to enable updating of the CPC configuration of the target SN.

Technical proposal

According to an embodiment of the present disclosure, a method for controlling a home node (MN) in a wireless communication system includes: in the case where a conditional primary Secondary Cell Group (SCG) cell (PSCell) change (CPC) has been previously configured for the terminal, and if an SN configuration is updated in a source Secondary Node (SN), receiving a first message comprising information about the updated SN configuration and a CPC configuration update indication; updating the previously configured MN configuration information based on the updated SN configuration information; transmitting a second message requesting to update the CPC configuration of the candidate target pscell for the target SN of the candidate target pscell of the terminal for which the CPC was previously configured, based on the CPC update configuration indication included in the first message, wherein the second message includes the CPC configuration update indication; and in the event that the CPC configuration of the candidate target pscell is updated by the target SN, receiving a third message from the target SN comprising updated CPC configuration information.

In accordance with another embodiment of the present disclosure, a method for controlling a source Secondary Node (SN) in a wireless communication system includes: updating the SN configuration in the source SN in case a conditional primary Secondary Cell Group (SCG) cell (PSCell) change (CPC) was previously configured for the terminal; and transmitting a first message to a Master Node (MN), the first message including information on an updated SN configuration and a CPC configuration update indication, wherein if MN configuration information previously configured is updated based on the information on the re-SN configuration, a second message is transmitted based on the CPC configuration update indication included in the first message, the second message requesting to update a CPC configuration of a candidate target pscell for a target SN of a candidate target pscell for which a CPC is previously configured, wherein the second message includes the CPC configuration update indication, and transmitting a third message including updated CPC configuration information from the target SN to the MN in case the CPC configuration of the candidate target pscell is updated by the target SN.

According to another embodiment of the present disclosure, a Master Node (MN) in a wireless communication system includes: a transceiver; and a controller that is controlled to: in the event that a conditional primary Secondary Cell Group (SCG) cell change (CPC) has been previously configured for the terminal, and if the Secondary Node (SN) configuration is updated in the source SN, receiving, by the transceiver, a first message comprising information about the updated SN configuration and a CPC configuration update indication; updating the previously configured MN configuration information based on the updated SN configuration information; transmitting, by the transceiver, a second message requesting to update the CPC configuration of the candidate target pscell for the target SN of the candidate target pscell of the terminal for which the CPC was previously configured based on the CPC update configuration indication included in the first message, wherein the second message includes the CPC configuration update indication; and in the event that the CPC configuration of the candidate target pscell is updated by the target SN, receiving, by the transceiver, a third message from the target SN comprising updated CPC configuration information.

According to another embodiment of the present disclosure, a source and Secondary Node (SN) in a wireless communication system includes: a transceiver; and a controller controlled to update an SN configuration in a source SN in case a conditional primary Secondary Cell Group (SCG) cell (psc) change (CPC) is previously configured for the terminal, and to transmit a first message including information on the updated SN configuration and a CPC configuration update indication to a Master Node (MN) through the transceiver; wherein if the previously configured MN configuration information is updated based on the information on the re-SN configuration, a second message is transmitted based on the CPC configuration update indication included in the first message requesting operation of updating the CPC configuration of the candidate target pscell for the target SN of the candidate target pscell of the terminal for which the CPC is previously configured, wherein the second message includes the CPC configuration update indication, and in case the CPC configuration of the candidate target pscell is updated by the target SN, a third message including the updated CPC configuration information from the target SN is transmitted to the MN.

Advantageous effects

According to an embodiment of the present disclosure, in order to solve the above-described problem, in the case where the configuration of the source SN is changed, the source SN notifies the MN of this change, and if the source SN previously transmitted the CPC configuration to the terminal, the source SN notifies the MN of the situation by including a corresponding CPC configuration update instruction. The MN updates the MN/MCG configuration in response to the indication, requests the target SN to update the CPC configuration, receives update information, and transmits the update information to the terminal, the update information including the updated source SN/MN/MCG configuration and the CPC configuration.

According to these embodiments, in the case of dual connectivity (dual connectivity or DC), if inter-SN CPC, MN/MCG configuration reflects a change in configuration of source SN to terminal configuration, and CPC configuration of target SN can be updated by inter-node signals, and CPC configuration of terminal and target SN can be synchronized by transmitting each updated configuration via one RRC message.

Drawings

Fig. 1 is a diagram illustrating a structure of an LTE system according to an embodiment of the present disclosure.

Fig. 2 is a diagram illustrating a structure of a radio protocol in an LTE system according to an embodiment of the present disclosure.

Fig. 3 is a diagram illustrating a structure of a next-generation mobile communication system according to an embodiment of the present disclosure.

Fig. 4 is a diagram illustrating a structure of a radio protocol in a next generation mobile communication system according to an embodiment of the present disclosure.

Fig. 5 is a diagram illustrating a Secondary Node (SN) configuration update procedure related to an embodiment of the present disclosure.

Fig. 6 is a diagram showing an SN configuration update procedure related to an embodiment of the present disclosure.

Fig. 7 is a diagram showing an SN configuration update procedure related to an embodiment of the present disclosure.

Fig. 8 is a block diagram illustrating a structure of a terminal according to an embodiment of the present disclosure.

Fig. 9 is a block diagram illustrating a structure of a base station according to an embodiment of the present disclosure.

Detailed Description

Hereinafter, preferred embodiments of the present disclosure will be described with reference to the accompanying drawings. In the drawings, like reference numerals refer to like elements. In other instances, well-known functions or constructions may not be described or shown in detail to avoid obscuring the subject matter of the present disclosure.

In describing exemplary embodiments of the present disclosure in the present specification, description of technical contents well known in the art to which the present disclosure pertains and having no direct relation to the present disclosure will be omitted. This is to more clearly convey the gist of the present disclosure by omitting unnecessary descriptions.

For the same reason, some components are exaggerated, omitted, or schematically shown in the drawings. Furthermore, the size of each component does not exactly reflect its actual size. In each of the drawings, identical or corresponding parts are indicated by identical reference numerals.

Various advantages and features of the present disclosure, as well as methods of accomplishing the same, will become apparent from the following detailed description of embodiments with reference to the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed herein, but is to be implemented in various forms. Embodiments the disclosure of the present disclosure is complete and provided so that those skilled in the art may readily understand the scope of the present disclosure. Accordingly, the disclosure is to be defined by the scope of the following claims. Like numbers refer to like elements throughout the specification.

In this document, it will be understood that each block of the flowchart illustrations, and combinations of blocks in the flowchart illustrations, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart block or blocks. These computer program instructions may also be stored in a computer-usable or computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-usable or computer-readable memory produce an article of manufacture including instruction means that implement the function specified in the flowchart block or blocks. The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks.

Furthermore, each block of the flowchart illustrations may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. .

Here, the term "unit" used in the present embodiment means a software or hardware component such as an FPGA or an ASIC, and the "unit" performs any role. However, the meaning of "unit" is not limited to software or hardware. The "unit" may be configured in a storage medium that may be addressed and may also be structured to reproduce one or more processors. Thus, for example, a "unit" includes components such as software components, object-oriented software components, class components and task components, as well as processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables. The functionality provided for in the components and "units" may be combined into a fewer number of components and "units" or may be further separated into additional components and "units". In addition, components and "units" may also be implemented to reproduce one or more CPUs within the device or secure multimedia card.

In the following description, terms indicating access nodes, network entities, messages, interfaces between network entities, and various identification information are used in order to facilitate an explanation of the present disclosure. Therefore, the terms used in the following description are not limited to specific meanings, and they may be replaced with other terms equivalent in technical sense.

In the following description, terms and definitions given in the 3 rd generation partnership project long term evolution (3 GPP LTE) standard and the New Radio (NR) rules are used for ease of explanation. However, the present disclosure is not limited by terms and definitions, and may be applied to other standard systems in the same manner.

In various embodiments of the present disclosure, a Master Node (MN) may be interpreted as a master base station and a Secondary Node (SN) may be interpreted as a secondary base station. Further, in various embodiments of the present disclosure, the MN and SN may be interpreted as different base stations, may be interpreted as base stations using different Radio Access Technologies (RATs), and in some cases, may be used as base stations using the same RAT. The MN and SN may be distinguished using general terms such as first base station, second base station, etc.

In various embodiments of the present disclosure, a Radio Resource Control (RRC) message transmitted by the MN may be referred to as an MN RRC message. In addition, the RRC message generated by the SN may be referred to as an SN RRC message.

Referring to fig. 1, as shown, a radio access network in a Long Term Evolution (LTE) system may include next generation base stations (evolved node bs (hereinafter, referred to as ENB), node bs, or base stations) 1-05, 1-10, 1-15, and 1-20, mobility Management Entities (MMEs) 1-25, and serving gateways (S-GWs) 1-30. The user equipments (UEs or terminals) 1-35 may be connected to an external network through the ENBs 1-05 to 1-20 and the S-GW 1-30.

In fig. 1, the ENBs 1-05 to 1-20 may correspond to existing node bs of a UMTS system. The ENB is connected to the UEs 1-35 through a radio channel, but may perform more complex functions than the existing node B. In the LTE system, all user traffic including real-time services such as voice over IP (VoIP) can be serviced through a shared channel. Therefore, an apparatus is required to perform scheduling based on the collected buffer, available transmit power, and state information of channels for the UE, and the ENBs 1-05 to 1-20 may be responsible for doing so. In a typical case, one END may control a plurality of cells. In order to achieve a data rate of, for example, 100Mbps in a bandwidth of, for example, 20MHz, an LTE system may use Orthogonal Frequency Division Multiplexing (OFDM) as a radio access technology. In addition, the LTE system may apply Adaptive Modulation and Coding (AMC) to determine a modulation scheme and a channel coding rate according to a channel state of the UE. The S-GW 1-30 is an entity that provides data bearers and can be created and removed under the control of the MME 1-25. The MME 1-25 is an entity responsible for various control functions of the UE 1-35, including mobility management functions, and may be connected to a plurality of ENBs 1-05 to 1-20.

Referring to fig. 2, in a UE or an ENB, radio protocols of an LTE system may include Packet Data Convergence Protocol (PDCP) 2-05, 2-40, radio Link Control (RLC) 2-10, 2-35, and Medium Access Control (MAC) 2-15, 2-30, respectively. PDCP 2-05, 2-40 may perform compression and decompression of IP headers. The main functions of PDCP 2-05, 2-40 can be summarized as follows.

Header compression and decompression function (header compression and decompression: ROHC only)

User data transfer function (transfer of user data)

Sequential delivery function (sequential delivery of upper layer PDUs in PDCP re-establishment procedure for RLC AM)

Reordering function (for separate bearers in DC (support of RLC AM only): PDCP PDU routing for transmission and PDCP PDU reordering for reception)

Duplicate detection function (duplicate detection of lower SDU during PDCP re-establishment of RLC AM)

Retransmission function (retransmission of PDCP SDUs at handover for RLC AM and retransmission of PDCP PDUs during PDCP data recovery for separate bearers in DC)

Encryption and decryption functions (encryption and decryption)

Timer-based SDU discard function (timer-based SDU discard in uplink)

Radio Link Control (RLC) 2-10, 2-35 may reconfigure PDCP Packet Data Units (PDUs) to an appropriate size and perform automatic repeat request (ARQ) operations. The main functions of the RLC 2-10, 2-35 can be summarized as follows.

Data transfer function (transfer of upper layer PDU)

ARQ function (error correction by ARQ (for AM data transfer only))

Concatenation, segmentation and reassembly functions (concatenation, segmentation and reassembly of RLC SDUs (for UM and AM data transfer only))

Re-segmentation function (re-segmentation of RLC data PDU (for AM data transfer only))

Reordering function (reordering of RLC data PDUs (for UM and AM data transfer only)

Duplicate detection function (duplicate detection (for UM and AM data transfers only))

Error detection function (protocol error detection (for AM data transfer only))

RLC SDU discard function (RLC SDU discard (for UM and AM data transfer only))

RLC re-establishment function (RLC re-establishment)

The MAC 2-15 or 2-30 may be connected to a plurality of RLC layer entities constructed in one UE, and it may multiplex and demultiplex RLC PDUs into MAC PDUs. The main functions of the MACs 2-15, 2-30 can be summarized as follows.

Mapping function (mapping between logical channels and transport channels)

Multiplexing and de-multiplexing functions (multiplexing MAC SDUs belonging to one or different logical channels to/from Transport Blocks (TBs) delivered to the physical layer on transport channels)

-scheduling information reporting function (scheduling information reporting)

HARQ (hybrid automatic repeat request) function (error correction by HARQ)

Priority handling function between logical channels (priority handling between logical channels of one UE)

Priority handling function between UEs (priority handling between UEs by means of dynamic scheduling)

-MBMS service identity function (MBMS service identity)

Transport format selection function (transport format selection)

Filling function (filling)

The Physical (PHY) layer 2-20, 2-25 may convert higher layer data into OFDM symbols by means of channel coding and modulation and transmit the OFDM symbols over a radio channel, or it may demodulate OFDM symbols received over a radio channel, perform channel decoding and convert the result to higher layers.

Referring to fig. 3, a radio access network of a next generation mobile communication system (hereinafter, referred to as NR or 5G) may include next generation base stations (new radio node bs (hereinafter, referred to as gnbs), NRNB, NR gnbs, or NR base stations) 3-10 and next generation new radio core networks (new radio core networks, NR CN) 3-05. The next generation new radio user equipment (NR UE or terminal) 3-15 can be connected to the external network through NR gNB 3-10 and NR CN 3-05.

In fig. 3, NR gNB 3-10 may correspond to an evolved node B (eNB) of an existing LTE system. The NR gNB 3-10 may be connected to the NR UE 3-15 through a radio channel and may provide superior service than an existing node B. In the next generation mobile communication system, all user traffic can be serviced through a shared channel. Thus, an entity that performs scheduling by collecting status information such as a buffer status, an available transmit power status, and a channel status of the UE is required, and the NR NB 3-10 can be responsible for doing so. One NR gNB can control a plurality of cells. In the next generation mobile communication system, in order to achieve ultra-high speed data transmission compared to the current LTE, a bandwidth exceeding the existing maximum bandwidth may be utilized. In addition, the beamforming technique may be additionally combined with Orthogonal Frequency Division Multiplexing (OFDM) used as a radio access technique. In addition, an Adaptive Modulation and Coding (AMC) scheme that determines a modulation scheme and a channel coding rate to match a channel state of the UE may be applied. The NR CN 3-05 may perform functions such as mobility support, bearer configuration, and quality of service (QoS) configuration. The NR CN 3-05 is an entity responsible for not only mobility management but also various control functions of the UE, and may be connected to a plurality of base stations. In addition, the next generation mobile communication system can interwork with the existing LTE system, and the NR CN 3-05 can be connected to the MME 3-25 through a network interface. The MME 3-25 may be connected to an existing base station eNB 3-30.

Referring to fig. 4, in the UE and the NR gNB, radio protocols of the next generation mobile communication system may include NR Service Data Adaptation Protocols (SDAPs) 4-01, 4-45, NR PDCP 4-05, 4-40, NR RLC 4-10, 4-35, and NR MACs 4-15 and 4-30, respectively.

The primary functions of NR SDAP 4-01, 4-45 can include some of the following functions.

User data transfer function (transfer of user plane data)

Mapping function between QoS flows and data bearers of uplink and downlink (mapping between QoS flows and DRBs (data radio bearers) of both DL and UL)

QoS flow ID marking function for uplink and downlink (marking QoS flow IDs in both DL and UL packets)

Function of mapping the reflective QoS flows to data bearers for uplink SDAP PDUs (reflective QoS flow to DRB mapping of UL SDAP PDUs)

Regarding the SDAP layer entity, for each PDCP layer entity, bearer, or logical channel, the UE may be configured with a function of whether to use a header of the SDAP layer entity or whether to use the SDAP layer entity through a Radio Resource Control (RRC) message. In the case of configured SDAP header, the UE may use a non-access stratum (NAS) reflective quality of service (QoS) configuration 1 bit indication of the SDAP header and an Access Stratum (AS) reflective QoS1 configuration 1 bit indication to indicate the update or reconfiguration of mapping information between QoS flows and data bearers of the uplink and downlink. The SDAP header can include QoS flow ID information indicating QoS. QoS information may be used as data processing priority and scheduling information to support smooth service.

The primary functions of NR PDCP 4-05, 4-40 can include some of the following functions.

User data transfer function (transfer of user data)

Sequential delivery function (sequential delivery of upper layer PDUs)

Out-of-order delivery function (out-of-order delivery of upper layer PDUs)

-a reordering function (PDCP PDU reordering for reception)

Duplicate detection function (duplicate detection of lower SDU)

Retransmission function (retransmission of PDCP SDU)

Encryption and decryption functions (encryption and decryption)

Timer-based SDU discard function (timer-based SDU discard in uplink)

In the above description, the reordering function of the NR PDCP entity may refer to a reordering function of PDCP PDUs received from a lower layer in order based on a PDCP Sequence Number (SN). The reordering function of the NR PDCP entity may include delivering data to a higher layer in a reordered sequence, directly delivering data regardless of order, recording lost PDCP PDUs by reordering, reporting a status of the lost PDCP PDUs to a transmitting side, and requesting retransmission of the lost PDCP PDUs.

The primary functions of NR RLCs 4-10, 4-35 may include some of the following functions.

Data transfer function (transfer of upper layer PDU)

Sequential delivery function (sequential delivery of upper layer PDUs)

Out-of-order delivery function (out-of-order delivery of upper layer PDUs)

ARQ function (error correction by ARQ)

Concatenation, segmentation and reassembly functions (concatenation, segmentation and reassembly of RLC SDUs)

Re-segmentation function (re-segmentation of RLC data PDU)

Reordering function (reordering of RLC data PDUs)

-repetition detection function (repetition detection)

Error detection function (protocol error detection)

RLC SDU discard function (RLC SDU discard)

RLC re-establishment function (RLC re-establishment)

In the above description, the in-order delivery function of the NR RLC entity may refer to an in-order delivery function of delivering RLC SDUs received from a lower layer to a higher layer. In case several RLC SDUs belonging to one original RLC SDU are received after segmentation, the sequential delivery function of the NR RLC entity may comprise reassembly and delivery of RLC SDUs.

The sequential delivery function of the NR RLC may include a function of reordering received RLC PDUs based on RLC Sequence Numbers (SNs) or PDCP SNs, recording missing RLC PDUs by reordering, reporting a status of the missing RLC PDUs to a transmitting side, and requesting retransmission of the missing RLC PDUs.

In the case where there is a missing RLC SDU, the in-order delivery function of the NR RLC entity may include an in-order delivery function of delivering only RLC SDUs preceding the missing RLC SDU to higher layers.

The in-order delivery function of the NR RLC entity may include an in-order delivery function of delivering all RLC SDUs received before the timer starts to a higher layer if a designated timer has expired, although there are missing RLC SDUs.

The in-sequence delivery function of the NR RLC entity may include an in-sequence delivery function of delivering all RLC SDUs received up to now to a higher layer if a specified timer has expired, although there are missing RLC SDUs.

The NR RLC may process RLC PDUs in the order of reception regardless of the order of sequence numbers and transmit them to the NR PDCP entity.

In case of receiving the segment, the NR RLC entity may reconstruct one complete RLC PDU from the segment stored in the buffer or received later and transfer it to the NR PDCP entity.

The NR RLC layer may not include a concatenation function, which may be performed by the NR MAC layer or may be replaced with a multiplexing function of the NR MAC layer.

In the above description, the out-of-order delivery function of the NR RLC entity may refer to a function of directly transferring RLC SDUs received from a lower layer to a higher layer regardless of the order. In case several RLC SDUs belonging to one original RLC SDU are received after segmentation, the out-of-order delivery function of the NR RLC entity may comprise a reassembly and delivery function of the RLC SDU. The out-of-order delivery function of the NR RLC entity may include a function of storing RLC SNs or PDCP SNs of the received RLC PDUs and ordering them to record missing RLC PDUs.

The NR MACs 4-15, 4-30 may be connected to several NR RLC layer entities constituted in one entity, and the main functions of the NR MACs 4-15, 4-30 may include some of the following functions.

Mapping function (mapping between logical channels and transport channels)

Multiplexing and demultiplexing functions (multiplexing/demultiplexing of MAC SDUs)

-scheduling information reporting function (scheduling information reporting)

HARQ functionality (error correction by HARQ)

-MBMS service identity function (MBMS service identity)

Transport format selection function (transport format selection)

Filling function (filling)

The NR PHY 4-20, 4-25 may compose OFDM symbols from higher layers of data and transmit over a radio channel by channel coding and modulation, or may demodulate and channel decode OFDM symbols received over a radio channel and convert the result to higher layers.

In various embodiments of the present disclosure, reference to a dual connectivity case may include LTE-NR dual connectivity (ENDC) where the core network is an Evolved Packet Core (EPC) and multi-RAT dual connectivity (MRDC) where the core network is a 5GC, and accordingly include operation of the network and terminal according to the RATs of the MN and SN. In the case of NR-DC, the core network is a 5GC.

Hereinafter, the present disclosure may use the following abbreviations.

SN: auxiliary node

MN: main node

MCG: master cell group

SCG: secondary cell group

Pcell: main cell

Pscell: primary SCG (secondary cell group) cell

SCell: secondary cell

SpCell: special cell

CHO: conditional switching

CPC: conditional PSCell change

S-SN: source SN

T-SN: target SN

SNModReq: SN change request information

SNChangeReq: SN change requirement information

SNAddReq: SN addition request information

SNAddReqACK: SN addition request acknowledgement message

SNModConfirms: SN change acknowledgement information

Fig. 5 is a diagram illustrating a Secondary Node (SN) configuration update procedure related to an embodiment of the present disclosure. Fig. 5 shows a case where the CPC configuration is updated using S-SN change request information.

After the CPC configuration is given to the UE, that is, in the case where the CPC configuration of the corresponding UE is maintained/managed in the S-SN, MN, and T-SN, a case where the S-SN configuration is changed is explained.

The S-SN may transmit the configuration change request information by delivering an snomodreq message to the MN. The SNModReq message may include the following information.

-information requesting SCG bearer change/release, change/release of SCG RLC bearer of split bearer or Pscell change in X2/Xn field (for security key change, PDCP restoration, etc.).

The information included in the RRC container part may include RRC configuration information (octet string) to be changed as S-SN configuration information.

-including a CPC configuration update indication in the X2/Xn related field.

The operation of the MN receiving the above message may include the following operations.

The MN reflects SCG configuration change request information present in the X2/Xn part and makes changes to the current MN configuration information. Such a change may be an addition/change/release of a bearer, and with respect to such a change, PDCP restoration, PDCP version change indication, or bearer type change for a separate bearer may be performed. During this process, the MN can transmit an SN change request back to the SN to perform the necessary request, if necessary. Additionally, the MN may update MCG configuration information provided to the UE.

-if a CPC configuration update indication is included, delivering RRC configuration information of the received S-SN to be changed to the T-SN of each candidate target pscell operating corresponding to the existing CPC configuration of the UE indicated in the received message. In addition, for each candidate target pscell, an update of the existing CPC configuration based on the received configuration information of the S-SN is requested.

In this case, the message used by the MN to deliver to the T-SN may be SNAddReq. Alternatively, a separate new X2/Xn message may be used.

In case a SNAddReq message is used for CPC update, the SNAddReq message may comprise CPC candidate target cell id and previously configured frequency information in the UE.

The SNAddReq message may comprise an indication indicating a CPC configuration change. The T-SN that received this indication updates the CPC candidate target cell configuration information of the previously configured CPC candidate target cell based on the new configuration information of the received S-SN of the candidate target pscell that has been admitted by the corresponding UE.

The T-SN may deliver the updated CPC configuration information to the MN by including it in the SNAddReqACK message. In this case, an updated RRC message may be included for each admitted candidate target cell, or a 1-bit indication indicating that the configuration of each candidate target cell is the same as the existing configuration in the case where CPC configuration information is not updated.

In case the above message is received from the T-SN, the MN can store the following information in its rrcrecon configuration message and deliver it to the UE.

-a: configuration information to be updated for S-SN, i.e. delta signal compared to existing S-SN configuration

-B: delta signal compared to existing MCG configuration considering updated configuration information of MN for S-SN update

-C: update configuration information of candidate target pscell reflecting configuration update of S-SN

-D: the above C, i.e. the update configuration information of MCG reflecting the update configuration information of the candidate target pscell

In this information, C and D are included in the conditional reconfigurations field, indicated by a specific ID, and applied in the case of meeting a specific condition associated with one candidate target pscell. The specific ID is a condition reconfiguration ID determined by the MN, and is updated with newly received C and D in case the UE has already had the condition reconfiguration indicated by the corresponding ID.

After receiving the rrcrecon configuration message, a given configuration is applied and the con-ditional reconfiguration is updated, and then the UE transmits the rrcrecon configuration complete message to the Mn. After receiving the message, the MN can deliver an SN change confirm (complete) message to the S-SN, thereby informing the S-SN that all requested changes to the S-SN configuration have been completed.

Fig. 6 is a diagram showing an SN configuration update procedure related to an embodiment of the present disclosure. Fig. 6 is an embodiment of updating CPC configuration using S-SN change requirement information.

In the embodiment shown in fig. 6, after CPC configuration is given to the UE, for example, in the case where CPC configuration of the corresponding UE is maintained/managed in S-SN, MN, and T-SN, a case where S-SN configuration is changed is explained.

The S-SN may transmit the configuration change request information by sending an SNChangeReq (e.g., SN change request) message to the MN. For example, the S-SN may determine to change the S-SN configuration. In addition, an SNChangeReq message may be transmitted to the MN based on the change in S-SN configuration.

The SNChangeReq message may include the following information.

For reference, in addition to the above information, information described in table 1 below may be included as SN configuration change request information. For a description of the information described in table 1, please refer to TS 38.423.

[ Table 1 ]

The information included in the RRC container may include RRC configuration information (octet string) of the S-SN to be changed.

In the Xn part, a CPC configuration update indication may be included.

The MN can make changes to the current MN configuration information by reflecting SCG configuration change request information present in the X2/Xn part. The change may be an addition/change/release of a bearer, and in this regard, the change may include PDCP restoration, PDCP version change indication, bearer type change for the separated bearer, and so on. During this process, the MN can transmit an SN change request back to the SN to perform the necessary request, if necessary. Additionally, the MN may update MCG configuration information transmitted to the UE.

If a CPC configuration update indication is included, the MN may deliver RRC configuration information to be changed of the received S-SN to the T-SN operating each candidate target pscell corresponding to the existing CPC configuration owned by the UE indicated in the received message. In addition, for each candidate target pscell, the MN may request that the T-SN update the existing CPC configuration based on the received configuration information of the S-SN.

In this case, the message used by the MN to deliver to the T-SN may be SNAddReq. Alternatively, a separate new Xn message may be provided.

The SNAddReq message may comprise an indication indicating a CPC configuration update. The T-SN receiving the indication indicating the CPC configuration update may update CPC candidate target cell configuration information of the previous configuration of the candidate target pscell that has been admitted by the corresponding UE based on the new configuration information of the received S-SN.

The T-SN may deliver the updated CPC configuration information to the MN by including it in the SNAddReqACK message. In this case, the SNAddReqACK message may include an updated RRC message for each admitted candidate target cell. In the case where no update has been made, the SNAddReqACK message may include a 1-bit indication indicating that the configuration of each candidate target cell is the same as the existing configuration.

In case a SNAddReqACK message is received from the T-SN, the MN can store the following information in its rrcrecon configuration message and deliver it to the UE.

-a: configuration information to be updated by the S-SN, e.g. delta signal compared to existing S-SN configuration

-D: above C, for example, update configuration information of MCG reflecting update configuration information of candidate target pscell

In these messages, C and D are included in the configurationreconfigurationfield and may be indicated with a specific ID. In addition, C and D above may be applied to the case where a particular condition associated with one candidate target pscell is satisfied. The specific id is a conditional reconfiguration id determined by the MN, and in case the UE already has a conditional reconfiguration indicated by the corresponding id, it can be updated with the newly received C and D.

After receiving the rrcreconditionionreconfiguration message, a given configuration is applied and the conditionlneconfiguration is updated, and then the UE can deliver the rrcreconditionlnomplete message to the Mn. After receiving the rrcrecon configuration complete message, the MN can deliver an SN change complete message to the S-SN, thereby informing the S-SN that all requested changes to the S-SN configuration have been completed.

Fig. 7 is a diagram showing an SN configuration update procedure related to an embodiment of the present disclosure. Fig. 7 is a case where a new CPC configuration reflecting the configuration of the S-SN to be updated is made after releasing the CPC configuration.

The case where the S-SN configuration is changed after CPC configuration is given is explained.

The S-SN delivers the snomodreq message to the MN. In this case, the SNModReq message includes information to be changed (information mentioned in the previous figures) and may include updated configuration information of the S-SN.

Additionally, the SNModReq information including the CPC release indication may be transmitted. The CPC release indication must be included in the Xn/X2 field.

The MN can receive the above message and update the configuration information of the MN and MCG with respect to the change request information of the corresponding S-SN. In addition, the MN may deliver updated configuration information including the updated MN/MCG configuration information and the received S-SN to the UE in the RRCRECONfigure. In this case, the MCG configuration information may include a release command for all CPC configurations the UE currently has.

An indication to release all CPC configurations may occur when a conditional reconfiguration release is commanded, or the release may be requested by directly indicating each condReconfig Id.

Additionally, in the current S-SN configuration, an indication indicating a release of measurement configuration information associated with the CPC configuration may be included in the measurement configuration.

* The UE receiving rrcrecon configuration applies the received MN/MCG/SCG configuration information and deletes all corresponding CPCs according to the release instruction.

* S-Sn uses the new source configuration and performs the normal CPC configuration procedure. For example, when SN change request information is sent to the MN, S-SN includes and delivers CPC configuration indication to the MN. The message may include a list of candidate target pscells selected by the S-SN and CPC execution conditions for each pscell. In addition, the current S-SN configuration may be included in the RRC octet string.

* The MN receiving this information may transmit a SNAddReq message to a candidate target T-SN corresponding to a candidate target pscell included in the received message. The SNAddReq message includes a list of candidate target pscells selected by the S-SN and may include the current configuration of the S-SN. If the T-SN that received the SNAddReq message identifies that the corresponding message is for a UE in which the T-SN previously maintained CPC configuration information, the T-SN may delete all CPC configuration information it maintains. In addition, the T-SN may select a final candidate target pscell from a received list of candidate target pscells of the S-SN based on measurement values transmitted from the S-SN to the MN. In addition, the T-SN may create a CPC configuration based on the S-SN configuration information of the selected pscell. In addition, the T-SN may deliver to the MN CPC configurations including those made for the selected candidate target pscell. The MN can map the execution condition, the configuration in the target cell, and the MCG configuration and deliver them to the UE with this configuration of each candidate target cell selected in the conditional reconfiguration field applied to one conditional reconfiguration id.

* The UE receiving the message from the MN may store the corresponding condition reconfiguration information and perform a measurement operation according to the execution condition.

In the case of the flowcharts of fig. 5 and 6 above, if the MN transmits a CPC configuration change indication in a SNAddReq message to the T-SN, the T-SN may update the preconfigured CPC configuration. In this case, if the configuration is the same as the existing CPC, the T-SN may include CG-Config (RRC message referring to CPC configuration) having a size of 0 in a field including CPC configuration of the SNAddReqACK message, or may not include a field including CPC configuration of the SNAddReqACK message at all. Upon receiving the SNAddReqACK message including the CG-Config of 0 size or the container field omitting the CG-Config, the MN may recognize that the CPC configuration of the corresponding candidate target pscell is the same as all configurations previously by the UE. The MN may recognize a CG-Config field of 0 size, or if a field including CPC configuration is not included in the SNAddReqACK, the MN may recognize that CPC configuration information of the corresponding candidate target pscell is the same as that of the previous delivery.

If a container field including the CPC configuration of each candidate target pscell is forcibly included in the SNAddReqACK message, another approach is to have the T-SN link the CPC configuration of each candidate target pscell to the SNAddReqACK message and transmit the X2/Xn field of the SNAddReqACK by including an ignore indication in the X2/Xn field of the SNAddReqACK. In this case, the MN that receives the field can know that there is no change from the existing CPC by ignoring the field.

There is a separate CPC configuration change vacancy handling indication in the SNAddReq message of the MN. If the indication is included in the SNAddReq message and delivered to the T-SN, the T-SN may not include the CPC configuration or may include an ignore indication in a container including the CPC configuration or append a CG-Config message having a 0-bit size when a response message is transmitted to the corresponding MN.

In the case of fig. 5 and 6, the rrcrecon configuration message eventually received from the MN may include (a) current S-SN configuration information, (B) current MN configuration information considering (a) and MCG configuration information, (C) an SCG configuration included in the rrcrecon configuration message associated with an id indicating a specific candidate target pscell in the condition reconfiguration field, and (D) CPC configuration and MCG configuration configured in consideration of the above CPC configuration, for example. In case the UE adds or alters a specific id of a condition reconfiguration field included in the finally received rrcrecon configuration message, only C or D may be changed compared to the former. For example, in the case where the MN requests CPC configuration or receives a SNAddReqACK message without CPC configuration information from a SNAddReq message having transmitted a request to change CPC configuration, the MN can recognize that there is no change information compared to the former. However, in the case where the request for CPC configuration information update is to change the original S-SN configuration and the current MN/MCG configuration is changed due to the change of the S-SN configuration, D (e.g., MCG configuration information in CPC configuration) based on the current MCG configuration may also be changed. For example, C may not change, but D may change. In this case, the MN stores the C information to be changed in the MCG configuration field in the rrcrecon configuration message to be overwritten in the condition reconfiguration field within the rrcrecon configuration message to be finally delivered for each candidate target pscell-related ID to be changed. The MN can also deliver unchanged D information by inserting existing D information back into the SCG configuration field. Also, the C information does not need to be changed according to the judgment of Mn, but if newly changed configuration information of D information is received from T-SN, mn stores D information to be changed in SCG configuration field within rrcrecon configuration message for each candidate target pscell-related ID to be modified. The MN can also deliver unchanged C information by inserting existing C information back into the MCG configuration field. In case the UE receives the addition/modification information of the condition reconfiguration field, the UE may replace the entire rrcrecon configuration message corresponding to the id.

In fig. 5 and 6, the Xn/X2 message informing the MN of the S-SN configuration change, requesting the MN to configure the T-SN and CPC, and causing the MN to receive the result may be the following message: meaning an SN change request or SN change request information or a new message of Xn/X2 for an individual CPC configuration update. In this case, each piece of information included in the initial message of fig. 5 and 6 may be included just like the new message.

Hereinafter, separately from what has been described previously, another embodiment related to conditional PScell addition/change (CPAC) will be described. In case the UE performs the CPAC, a pscell addition/change failure may occur if a given T304 timer expires when random access is performed to the target cell. In this case, the UE may select a new candidate target pscell from among given CPAC candidate target pscells and perform a pscell addition/change on the selected cell based on the following.

* After selecting the same cell as the cell selection procedure performed in idle/inactive state, in case the selected cell is one of the respective candidate target pscell associated with the CPAC configuration

* Among the respective candidate target pscell associated with the respective CPAC configuration, the candidate target cell having the highest measured cell signal strength

* Among the respective candidate target pscell associated with the respective CPAC configuration, any of the candidate target cells having cell signal strengths greater than a predetermined threshold are measured

* Among the respective candidate target pscell associated with the respective CPAC configuration, the cell with the highest strength among the candidate target cells having a cell signal strength greater than a predetermined threshold is measured

* Among the respective candidate target pscell associated with the respective CPAC configuration, among the candidate target cells having measured cell signal strengths greater than a predetermined threshold, a cell in which the number of beams exceeding the threshold of the particular beam exceeds the predetermined number

* Random cells selected by a UE among respective candidate target pscells associated with respective CPAC configurations

In case that no cell satisfies the above criteria, the UE may perform the scgfailurenformation procedure. Alternatively, the UE may perform the SCGFailureInformation process in case the above criteria are satisfied or the following conditions are satisfied in addition to the case where there is a cell selected by the UE.

* In the case where there is a cell that meets the above criteria and the pscell addition/change procedure fails when the pscell addition/change procedure is performed on that cell,

* In case that a cell meets the above criteria, an attempt is made to perform a predefined number of pscell addition/change procedures on the cell, and all the execution attempts of this number eventually fail (for reference, after one failed attempt, the T304 timer is restarted, and can be regarded as failed when this timer expires.)

* In case that the result of performing the pscell addition/change on the cell satisfying the above criteria is failure, the UE may repeat the pscell addition/change operation by applying the above criteria again at the time of failure. In case the UE repeats the operation more than a predefined number of times,

this procedure is a procedure for transmitting the SCGFailureInformation message to the SN over the link of the MN. The scgfailurenformation message may include a measurement result value of each cell and beams of the serving cell and neighbor cells. In the case of performing a conditional or unconditional pscell addition/change and failing, the UE may include an indication indicating that the conditional or unconditional pscell addition/change fails in a corresponding message. Additionally, SCGFailureInformation may be delivered to the SN, including an indication of the corresponding failed pscell (e.g., at least one of ARFCN, CGI, PCI and related condition reconfiguration ID).

Fig. 8 is a block diagram illustrating an internal structure of a terminal according to an embodiment of the present disclosure.

Referring to the drawings, a terminal may include a Radio Frequency (RF) processor 5-10, a baseband processor 5-20, a storage device 5-30, and a controller 5-40. In addition, the controller 5-40 may also include a multi-connection processor 5-42.

The RF processors 5-10 perform functions for transmitting or receiving signals over a wireless channel, such as signal band changing, amplifying, etc. That is, the RF processor 5-10 up-converts the baseband signal supplied from the baseband processor 5-20 into an RF band signal and then transmits the RF band signal through the antenna, and down-converts the RF band signal received through the antenna into a baseband signal. For example, the RF processors 5-10 may include transmit filters, receive filters, amplifiers, mixers, oscillators, digital-to-analog converters (DACs), analog-to-digital converters (ADCs), and the like. In the drawings, only one antenna is shown, but the terminal may include a plurality of antennas. In addition, the RF processor 5-10 may include a plurality of RF chains. In addition, the RF processors 5-10 may perform beamforming. To perform beamforming, the RF processor 5-10 may adjust the phase and magnitude of each of the signals transmitted and received through multiple antennas or antenna elements. Further, the RF processor may perform MIMO, and may receive multiple layers when performing MIMO operation.

The baseband processor 5-20 performs the function of converting between baseband signals and bit streams according to the physical layer protocol of the system. For example, when transmitting data, the baseband processor 5-20 generates complex symbols by encoding and modulating a transmission bit stream. In addition, when data is received, the baseband processor 5-20 reconstructs a received bit stream by demodulating and decoding the baseband signal supplied from the RF processor 5-10. For example, in case of applying an Orthogonal Frequency Division Multiplexing (OFDM) scheme, when transmitting data, the baseband processor 5-20 generates complex symbols by encoding and modulating a transmission bit stream, maps the complex symbols to subcarriers, and then constructs OFDM symbols by Inverse Fast Fourier Transform (IFFT) calculation and Cyclic Prefix (CP) insertion. Further, when data is received, the baseband processor 5-20 separates the baseband signals supplied from the RF processor 5-10 in units of OFDM symbols, reconstructs signals mapped to subcarriers through Fast Fourier Transform (FFT), and then reconstructs a received bit stream through demodulation and decoding.

The baseband processor 5-20 and the RF processor 5-10 transmit and receive signals as described above. Thus, the baseband processor 5-20 and the RF processor 5-10 may be referred to as a transmitter, receiver, transceiver, transceiving means, or communicator. Further, at least one of the baseband processor 5-20 and the RF processor 5-10 may include a plurality of communication modules to support a plurality of different radio access technologies. In addition, at least one of the baseband processor 5-20 and the RF processor 5-10 may include different communication modules to process signals of different frequency bands. For example, the different radio access technologies may include wireless LANs (e.g., IEEE 802.11), cellular networks (e.g., LTE), and so on. Further, the different frequency bands may include an ultrahigh frequency (SHF) (e.g., 2.NRhz, NRhz) frequency band, a millimeter (mm) wave (e.g., 60 GHz) frequency band, and the like.

The storage devices 5-30 store data such as basic programs, application programs, and configuration information for the operation of the terminal. In particular, the storage device 5-30 may store information related to a second access node performing radio communication by using a second radio access technology. The storage device 5-30 provides the stored data in response to a request by the controller 5-40.

The controllers 5-40 control the overall operation of the terminal. For example, the controller 5-40 transmits or receives signals via the baseband processor 5-20 and the RF processor 5-10. In addition, the controller 5-40 records data in and reads data from the storage device 5-40. To this end, the controller 5-40 may comprise at least one processor. For example, the controllers 5 to 40 may include a Communication Processor (CP) executing control for communication and an Application Processor (AP) controlling higher layers such as an application program. In addition, the controllers 5-40 may control the operation of the terminals according to various embodiments of the present disclosure or entities corresponding thereto.

As shown in the figures, the base station may include an RF processor 6-10, a baseband processor 6-20, a backhaul communicator 6-30, a storage device 6-40, and a controller 6-50. The controller 6-50 may also include a multi-connection processor 6-52.

The RF processors 6-10 perform functions for transmitting or receiving signals over a wireless channel, such as signal band changing, amplifying, etc. That is, the RF processor 6-10 up-converts the baseband signal supplied from the baseband processor 6-20 into an RF band signal and then transmits the RF band signal through the antenna, and down-converts the RF band signal received through the antenna into a baseband signal. For example, the RF processors 6-10 may include transmit filters, receive filters, amplifiers, mixers, oscillators, DACs, ADCs, and the like. In the figures, only one antenna is shown, but the first access node may comprise multiple antennas. In addition, the RF processor 6-10 may include a plurality of RF chains. In addition, the RF processor 6-10 may perform beamforming. To perform beamforming, the RF processor 6-10 may adjust the phase and size of each of the signals transmitted and received via multiple antennas or antenna elements. The RF processor may perform downlink MIMO operation by transmitting one or more layers.

The baseband processor 6-20 performs the function of converting between baseband signals and bit streams according to the physical layer protocol of the first radio access technology. For example, when transmitting data, the baseband processor 6-20 generates complex symbols by encoding and modulating a transmitted bit stream. In addition, when data is received, the baseband processor 6-20 reconstructs a received bit stream by demodulating and decoding the baseband signal supplied from the RF processor 6-10. For example, in the case of applying the OFDM scheme, when transmitting data, the baseband processor 6-20 generates complex symbols by encoding and modulating a transmission bit stream, maps the complex symbols to subcarriers, and then constructs OFDM symbols by IFFT computation and CP insertion. Further, when data is received, the baseband processor 6-20 separates the baseband signals supplied from the RF processor 6-10 in units of OFDM symbols, reconstructs signals mapped to subcarriers through FFT computation, and then reconstructs a received bit stream through demodulation and decoding. The baseband processor 6-20 and the RF processor 6-10 transmit and receive signals as described above. Thus, the baseband processor 6-20 and the RF processor 6-10 may be referred to as a transmitter, a receiver, a transceiver, a transceiving unit, a communication unit, or a wireless communication unit.

Backhaul communicators 6-30 provide interfaces for performing communications with other nodes within the network. That is, the backhaul communicator 6-30 converts a bit stream transmitted from the primary base station to another node (e.g., a secondary base station, a core network, etc.) into a physical signal, and converts a physical signal received from the other node into a bit stream.

The storage devices 6-40 store data such as basic programs, application programs, and configuration information for the operation of the base station. Specifically, the storage devices 6-40 may store information about bearers allocated to the connected terminals, measurement results reported from the connected terminals, and the like. Further, the storage device 6-40 may store information serving as a determination criterion of whether to provide or stop providing multiple connections to the UE. The storage device 6-40 provides stored data in response to a request by the controller 6-50.

The controllers 6-50 control the overall operation of the base station. For example, the controller 6-50 transmits or receives signals via the baseband processor 6-20 and the RF processor 6-10 or via the backhaul communicator 6-30. In addition, the controller 6-50 records data in and reads data from the storage device 6-40. To this end, the controllers 6-50 may include at least one processor. In addition, the controllers 6-50 may control the operation of the base stations according to various embodiments of the present disclosure or entities corresponding thereto.

Meanwhile, the embodiments of the present disclosure described with reference to the present specification and the drawings are merely specific examples illustrated for convenience of description and understanding of the present disclosure, and are not intended to limit the scope of the present disclosure. It will be apparent to those skilled in the art that other modifications based on the technical spirit of the present disclosure may be implemented.

In addition, the embodiments of the present disclosure described and illustrated in the specification and drawings are merely specific embodiments presented for ease of explanation of the disclosure and to aid in understanding the disclosure, and are not intended to limit the scope of the disclosure. Accordingly, it should be construed that all changes or modified forms derived from the technical ideas of the present disclosure, except the embodiments disclosed herein, fall within the scope of the present disclosure.

Claims

1. A method of controlling a master node MN in a wireless communication system, comprising:

in case that the SCG cell PScell of the conditional primary and secondary cell group has been previously configured for the terminal to change CPC, if the SN configuration is updated in the source secondary node SN, receiving a first message comprising information about the updated SN configuration and a CPC configuration update indication;

updating previously configured MN configuration information based on the updated SN configuration information;

Transmitting a second message requesting a target SN operating a candidate target PSCell to update the CPC configuration of the candidate target PSCell based on the CPC update configuration indication included in the first message, the candidate target PSCell for the terminal for which the CPC was previously configured, the second message including the CPC configuration update indication; and

in the case that the CPC configuration of the candidate target PSCell is updated by the target SN, a third message is received from the target SN that includes the updated CPC configuration information.

2. The method of claim 1, further comprising transmitting a fourth message to the terminal, the fourth message including the updated SN configuration information, the updated MN configuration information, the updated CPC configuration information, and primary cell group, MCG, configuration information updated based on the updated CPC configuration information.

3. The method of claim 1, wherein the second message further comprises information received from the SN regarding updated SN configuration, and

wherein the CPC configuration previously configured for the candidate target PSCell is updated by the target SN based on information about the updated SN configuration.

4. The method of claim 1, wherein the third message comprises the CPC configuration information updated for a first candidate PSCell if the CPC configuration is updated for the first candidate PSCell, and comprises an indication that the CPC configuration information is not updated for a second candidate PSCell if the CPC configuration information is not updated for the second candidate PSCell.

5. A method of controlling a source secondary node SN in a wireless communication system, comprising:

updating the SN configuration in the source SN under the condition that the SCG cell PScell of the conditional primary and secondary cell groups is configured for the terminal to change CPC; and

transmitting a first message to the master node MN, the first message comprising information about the updated SN configuration and a CPC configuration update indication,

wherein if MN configuration information previously configured is updated based on information on an updated SN configuration, a second message requesting that a target SN operating a candidate target PSCell update the CPC configuration of the candidate target PSCell is transmitted based on the CPC configuration update indication included in the first message, the candidate target PSCell being for the terminal for which the CPC was previously configured, the second message including the CPC configuration update indication, and a third message including the updated CPC configuration information from the target SN is transmitted to the MN in case the CPC configuration of the candidate target PSCell is updated by the target SN.

6. The method of claim 5, further comprising transmitting a fourth message to the terminal, the fourth message comprising the updated SN configuration information, the updated MN configuration information, the updated CPC configuration information, and primary cell group, MCG, configuration information updated based on the updated CPC configuration information.

7. The method of claim 5, wherein the second message further comprises information received from the SN regarding updated SN configuration, and

8. The method of claim 1, wherein the third message comprises the CPC configuration information updated for a first candidate PSCell if the CPC configuration is updated for the first candidate PSCell, and comprises an indication that the CPC configuration information is not updated for a second candidate PSCell if the CPC configuration information is not updated for the second candidate PSCell.

9. A master node, MN, in a wireless communication system, comprising:

a transceiver; and

a controller, the controller being controlled to:

In case that the CPC is changed by the SCG cell PSCell, which previously configured the conditional primary and secondary cell group for the terminal, if the SN configuration is updated in the source secondary node SN, receiving a first message by the transceiver, the first message including information on the updated SN configuration and a CPC configuration update indication;

transmitting, by the transceiver, a second message requesting a target SN operating a candidate target PSCell for the terminal for which the CPC was previously configured to update the CPC configuration of the candidate target PSCell based on the CPC update configuration indication included in the first message, the second message including the CPC configuration update indication; and

in the case that the CPC configuration of the candidate target PSCell is updated by the target SN, a third message including the updated CPC configuration information is received from the target SN by the transceiver.

10. The MN of claim 9, wherein the controller is configured to transmit a fourth message to the terminal via the transceiver, the fourth message including the updated SN configuration information, the updated MN configuration information, the updated CPC configuration information, and the primary cell group MCG configuration information updated based on the updated CPC configuration information.

11. The MN of claim 9, wherein the second message further comprises information received from the SN regarding updated SN configuration, and

12. The MN of claim 9, wherein the third message comprises the CPC configuration information updated for a first candidate PSCell if the CPC configuration is updated for the first candidate PSCell, and comprises an indication that the CPC configuration information is not updated for a second candidate PSCell if the CPC configuration information is not updated for the second candidate PSCell.

13. A source secondary node SN in a wireless communication system, comprising:

a transceiver; and

a controller, the controller being controlled to: updating the SN configuration in the source SN under the condition that the SCG cell PScell of the conditional primary and secondary cell group is configured for the terminal to change CPC; and transmitting, by the transceiver, a first message to the master node MN, the first message including information about the updated SN configuration and a CPC configuration update indication,

Wherein if MN configuration information previously configured is updated based on information on an updated SN configuration, a second message including the CPC configuration update indication is transmitted based on the CPC configuration update indication included in the first message requesting that a target SN operating a candidate target PSCell update the CPC configuration of the candidate target PSCell for the terminal for which the CPC was previously configured, and a third message including the updated CPC configuration information from the target SN is transmitted to the MN in case the CPC configuration of the candidate target PSCell is updated by the target SN.

14. The source SN of claim 13 wherein a fourth message is transmitted to the terminal, the fourth message including the updated SN configuration information, the updated MN configuration information, the updated CPC configuration information, and primary cell group MCG configuration information updated based on the updated CPC configuration information,

wherein the second message further includes information received from the SN regarding updated SN configuration, an

15. The source SN of claim 13, wherein the third message comprises the CPC configuration information updated for a first candidate target PSCell if the CPC configuration is updated for the first candidate PSCell, and the third message comprises an indication that the CPC configuration information is not updated for a second candidate target PSCell if the CPC configuration is not updated for the second candidate PSCell.