Method and apparatus for processing packets in a next generation mobile communication system

Abstract

The present disclosure relates to a communication method and system for converging technologies of a 5th generation (5G) communication system and the Internet of Things (IoT), wherein the 5th generation communication system is used to support higher data rates than a 4th generation (4G) system. The present disclosure can be applied to intelligent services based on 5G communication technology and IoT-related technologies (such as smart homes, smart buildings, smart cities, smart cars, connected cars, health care, digital education, smart retail, safety and security services). A method for operating a terminal includes: receiving packet replication data radio bearer (DRB) configuration information from a base station, receiving a media access control (MAC) control element (CE) including information indicating whether packet replication has been activated from the base station, and determining whether to activate the packet replication bearer based on the packet replication DRB configuration information and the MAC CE.

Description

[0001] This application is a divisional application of the invention patent with application date of June 14, 2018, application number 201810612210.4, and invention name “Method and device for processing packets in the next generation mobile communication system”. Technical Field

[0002] The present disclosure relates to terminal and base station operations in a next generation mobile communication system.

[0003] The present disclosure relates to a method for performing a PDCP COUNT CHECK operation in a next generation mobile communication system and an apparatus for performing the method.

[0004] Furthermore, the present disclosure relates to operations and apparatus for activating and deactivating packet duplication in a next generation mobile communication system.

[0005] Furthermore, the present disclosure relates to a method and apparatus for processing packet copy transmission failure in a next generation mobile communication system. Background Art

[0006] In order to meet the growing demand for wireless data traffic since the deployment of 4G communication systems, efforts have been made to develop improved 5G or pre-5G communication systems. Therefore, 5G or pre-5G communication systems are also referred to as "super 4G networks" or "post-LTE systems". 5G communication systems are considered to be implemented in higher frequency (millimeter wave (mm Wave)) bands, for example, 60GHz bands, in order to achieve higher data rates. In order to reduce the propagation loss of radio waves and increase the transmission distance, beamforming, massive multiple-input multiple-output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and massive antenna technology are discussed in 5G communication systems. In addition, in 5G communication systems, research and development for system network improvements are underway based on advanced small cells, cloud radio access networks (RAN), ultra-dense networks, device-to-device (D2D) communications, wireless backhaul, mobile networks, cooperative communications, coordinated multi-point (Comp), and receiver interference cancellation. In 5G systems, hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC) as advanced coding modulation (ACM) have been developed, as well as filter bank multi-carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) as advanced access technologies.

[0007] The Internet is currently evolving into the Internet of Things (IoT), a network of connected things centered around people generating and consuming information, and the Internet of Things, where distributed entities such as things exchange and process information without human intervention. The Internet of Everything (IoE), a combination of IoT technology and big data processing technology connected to cloud servers, has emerged. With technological elements such as sensing technology, wired / wireless communication and network infrastructure, service interface technology, and security technology required for IoT implementation, sensor networks, machine-to-machine (M2M) communication, and machine-type communication (MTC) have recently been researched. Such IoT environments can provide intelligent Internet technology services that create new value for human life by collecting and analyzing data generated by connected things. Through the integration and combination of existing information technology (IT) and various industrial applications, the IoT can be applied in a variety of fields, including smart homes, smart buildings, smart cities, smart cars or connected vehicles, smart grids, healthcare, smart appliances, and advanced medical services.

[0008] To this end, various attempts have been made to apply 5G communication systems to IoT networks. For example, technologies such as sensor networks, machine-type communications (MTC), and machine-to-machine (M2M) communications can be implemented using beamforming, MIMO, and array antennas. The application of cloud radio access networks (RAN), a big data processing technology described above, can also be considered an example of the convergence between 5G and IoT technologies. Summary of the Invention

[0009] According to some embodiments of the present disclosure, a method performed by a terminal is provided, the method comprising: receiving a counter check request message including a data radio bearer (DRB) count most significant bit (MSB) information list from a base station; identifying, in a case where a first DRB is included in the DRB count MSB information list, whether a downlink most significant bit (MSB) value of the terminal for the first DRB is different from a downlink MSB value of the base station for the first DRB indicated by the DRB count MSB information list, wherein the downlink MSB value of the terminal for the first DRB is determined based on a highest count value of a PDCP SDU in a packet data convergence protocol (PDCP) service data unit (SDU) that has been received; and sending a counter check response message to the base station, wherein, in a case where the downlink MSB value of the terminal for the first DRB is different from the downlink MSB value of the base station for the first DRB, the counter check response message includes first DRB count information associated with the first DRB, wherein the first DRB count information is a first PDCP count corresponding to the downlink MSB value of the terminal for the first DRB. The counter check response message includes the second DRB count information of the second DRB of the cell group of the terminal, and wherein, in a case where the second DRB is not included in the DRB count MSB information list, the counter check response message includes the second DRB count information of the second DRB of the cell group of the terminal, wherein the second DRB count information is the full count value of the second PDCP SDU corresponding to the downlink MSB value of the terminal for the second DRB.

[0010] According to some embodiments of the present disclosure, a method performed by a base station is provided, the method comprising: sending a counter check request message including a data radio bearer (DRB) count most significant bit (MSB) information list to a terminal; and receiving a counter check response message from the terminal, wherein, in a case where a first DRB is included in the DRB count MSB information list, whether a downlink most significant bit (MSB) value of the terminal for the first DRB is different from a downlink MSB value of the base station for the first DRB indicated by the DRB count MSB information list is identified by the terminal, wherein the downlink MSB value of the terminal for the first DRB is determined based on a highest count value of a PDCP SDU in a received Packet Data Convergence Protocol (PDCP) service data unit (SDU), wherein, in a case where the downlink MSB value of the terminal for the first DRB is different from a downlink MSB value of the base station for the first DRB, the counter check response message includes first DRB count information associated with the first DRB, wherein the first DRB count information is a first PDCP count information corresponding to the downlink MSB value of the terminal for the first DRB. The counter check response message includes the second DRB count information of the second DRB of the cell group of the terminal, and wherein, in a case where the second DRB is not included in the DRB count MSB information list, the counter check response message includes the second DRB count information of the second DRB of the cell group of the terminal, wherein the second DRB count information is the full count value of the second PDCP SDU corresponding to the downlink MSB value of the terminal for the second DRB.

[0011] According to some embodiments of the present disclosure, a terminal is provided, comprising: a transceiver; and a controller, configured to: receive a counter check request message including a data radio bearer (DRB) count most significant bit (MSB) information list from a base station via the transceiver, identify, in a case where a first DRB is included in the DRB count MSB information list, whether a downlink most significant bit (MSB) value of the terminal for the first DRB is different from a downlink MSB value of the base station for the first DRB indicated by the DRB count MSB information list, wherein the downlink MSB value of the terminal for the first DRB is determined based on a highest count value of a PDCP SDU in a received Packet Data Convergence Protocol (PDCP) service data unit (SDU), and send a counter check response message to the base station via the transceiver, wherein, in a case where the downlink MSB value of the terminal for the first DRB is different from the downlink MSB value of the base station for the first DRB, the counter check response message includes first DRB count information associated with the first DRB, wherein the first DRB count information is a first PDCP count information corresponding to the downlink MSB value of the terminal for the first DRB. The counter check response message includes the second DRB count information of the second DRB of the cell group of the terminal, and wherein, in a case where the second DRB is not included in the DRB count MSB information list, the counter check response message includes the second DRB count information of the second DRB of the cell group of the terminal, wherein the second DRB count information is the full count value of the second PDCP SDU corresponding to the downlink MSB value of the terminal for the second DRB.

[0012] According to some embodiments of the present disclosure, a base station is provided, comprising: a transceiver; and a controller, configured to: send a counter check request message including a data radio bearer DRB count most significant bit MSB information list to a terminal via the transceiver, and receive a counter check response message from the terminal via the transceiver, wherein, in a case where a first DRB is included in the DRB count MSB information list, whether the downlink most significant bit MSB value of the terminal for the first DRB is different from the downlink MSB value of the base station for the first DRB indicated by the DRB count MSB information list is identified by the terminal, wherein the downlink MSB value of the terminal for the first DRB is based on a PDCP service data unit (SDU) in a received PDCP service data unit (PDCP). The counter check response message is determined based on the highest count value of the SDU, wherein, in a case where the downlink MSB value of the terminal for the first DRB is different from the downlink MSB value of the base station for the first DRB, the counter check response message includes first DRB count information associated with the first DRB, wherein the first DRB count information is the full count value of the first PDCP SDU corresponding to the downlink MSB value of the terminal for the first DRB, and wherein, in a case where the second DRB is not included in the DRB count MSB information list, the counter check response message includes second DRB count information of the second DRB of the cell group of the terminal, wherein the second DRB count information is the full count value of the second PDCP SDU corresponding to the downlink MSB value of the terminal for the second DRB.

[0013] The present disclosure may provide a method for a base station to request a count check from a terminal in a next-generation mobile communication system and for the terminal to perform a corresponding operation. Specifically, when taking into account PDCP reordering, the present disclosure may provide a method different from the existing LTE method. For example, in the next generation of mobile communications, LTE and New Radio (NR) may operate in a dual-connection manner. In such a case, different count check operations may be performed in a Master Cell Group (MCG) and a Secondary Cell Group (SCG), and the operations need to be performed independently.

[0014] In addition, the present disclosure may provide content related to packet-duplicated data transmission, which is newly introduced in next-generation mobile communication systems, and clearly define the operation of a terminal when the terminal receives activation or deactivation of packet duplication from a base station via a Medium Access Control (MAC) control element (CE). Embodiments of the present disclosure may provide detailed operations in the MAC when activation or deactivation of packet duplication is received.

[0015] Furthermore, the present disclosure may provide a method and apparatus for handling packet copy transmission failure in a next generation mobile communication system.

[0016] An embodiment of the present disclosure provides a method for operating a terminal, comprising: receiving packet replication data radio bearer (DRB) configuration information from a base station; receiving a media access control (MAC) control element (CE) including information indicating whether packet replication has been activated from the base station; and determining whether to activate the packet replication bearer based on the packet replication DRB configuration information and the MAC CE.

[0017] In addition, an embodiment of the present disclosure provides a terminal including: a transceiver configured to send and receive signals; and a controller configured to control receiving packet replication data radio bearer (DRB) configuration information from a base station; receiving a media access control (MAC) control element (CE) including information indicating whether packet replication has been activated from the base station; and determining whether to activate the packet replication bearer based on the packet replication DRB configuration information and the MAC CE.

[0018] In addition, an embodiment of the present disclosure provides a method for operating a base station, comprising: sending packet replication data radio bearer (DRB) configuration information to a terminal; and sending a media access control (MAC) control element (CE) to the terminal including information indicating whether packet replication has been activated, wherein whether the packet replication bearer is activated is determined based on the packet replication DRB configuration information and the MAC CE.

[0019] In addition, an embodiment of the present disclosure provides a base station, comprising: a transceiver configured to send and receive signals; and a controller configured to send packet replication data radio bearer (DRB) configuration information to a terminal and send a media access control (MAC) control element (CE) to the terminal including information indicating whether packet replication has been activated, wherein whether the packet replication bearer is activated is determined based on the packet replication DRB configuration information and the MAC CE.

[0020] Before proceeding with the following detailed description, it may be helpful to set forth definitions of certain words and phrases used throughout this patent document. The terms "include" and "comprising" and their derivatives are meant to include, but are not limited to; the term "or" is inclusive, meaning and / or; the phrases "associated with" and "associated with" and their derivatives may mean include, be included within, interconnected with, contain, be contained within, connect to or be connected with, couple to or be coupled with, communicate with, cooperate with, intertwine, juxtapose, be proximate, be bound to or be bound with, have, have the property of, and the like; and the term "controller" means any device, system, or portion thereof that controls at least one operation, such device being implemented in hardware, firmware, or software, or some combination of at least two thereof. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely.

[0021] Moreover, the various functions described below can be implemented or supported by one or more computer programs, each of which is formed by a computer-readable program code and is specifically implemented in a computer-readable medium. The terms "application" and "program" refer to one or more computer programs, software components, instruction sets, processes, functions, objects, classes, instances, related data or parts thereof that are suitable for implementation with suitable computer-readable program code. The phrase "computer-readable program code" includes any type of computer code, including source code, object code and executable code. The phrase "computer-readable medium" includes any type of medium that can be accessed by a computer, such as a read-only memory (ROM), a random access memory (RAM), a hard drive, a compact disc (CD), a digital video disc (DVD) or any other type of memory. "Non-transient" computer-readable media excludes wired, wireless, optical or other communication links that transmit transient electrical signals or other signals. Non-transient computer-readable media include media in which data can be permanently stored and media in which data can be stored and subsequently rewritten, such as rewritable optical discs or erasable memory devices.

[0022] Definitions for certain words and phrases are provided throughout this patent document. Those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which like reference numerals represent like parts:

[0024] Figure 1A is a diagram showing a configuration of an LTE system according to an embodiment of the present disclosure;

[0025] Figure 1B is a diagram illustrating a radio protocol architecture in an LTE system according to an embodiment of the present disclosure;

[0026] Figure 1C is a diagram showing a configuration of a next-generation mobile communication system according to an embodiment of the present disclosure;

[0027] Figure 1D is a diagram illustrating a radio protocol architecture of a next-generation mobile communication system according to an embodiment of the present disclosure;

[0028] Figure 1E is a diagram showing a structure of a COUNT value in LTE according to an embodiment of the present disclosure;

[0029] Figure 1F is a diagram illustrating an encryption process in AS security of an LTE system in order to describe an example of using a COUNT value of the present disclosure;

[0030] Figure 1G is a diagram illustrating a COUNT CHECK operation in LTE according to an embodiment of the present disclosure;

[0031] Figure 1H is a diagram illustrating an entire COUNT CHECK operation in a next-generation mobile communication system according to an embodiment of the present disclosure;

[0032] Figure 1I is a diagram illustrating the operation of a UE according to an embodiment of the present disclosure;

[0033] Figure 1J is a diagram showing a configuration of a UE according to an embodiment of the present disclosure;

[0034] Figure 1K is a diagram showing a configuration of an eNB according to an embodiment of the present disclosure;

[0035] Figure 2A is a diagram showing a configuration of an LTE system according to an embodiment of the present disclosure;

[0036] Figure 2B is a diagram illustrating a radio protocol architecture in an LTE system according to an embodiment of the present disclosure;

[0037] Figure 2Cis a diagram schematically illustrating dual connectivity and carrier operations in an LTE system according to an embodiment of the present disclosure;

[0038] Figure 2D is a diagram illustrating a radio protocol architecture of a next-generation mobile communication system according to an embodiment of the present disclosure;

[0039] Figure 2E is a diagram showing a configuration of a next-generation mobile communication system according to an embodiment of the present disclosure;

[0040] Figure 2F is a diagram schematically illustrating data transmission through packet duplication considered in an embodiment of the present disclosure and showing a process in which a UE processes a duplicated packet based on various conditions proposed in this embodiment;

[0041] Figure 2G is a diagram showing the structure of a packet copy activation / deactivation MAC CE according to an embodiment of the present disclosure;

[0042] Figure 2H is a diagram illustrating operations in a MAC after packet duplication is activated or deactivated according to an embodiment of the present disclosure;

[0043] Figure 2I is a diagram illustrating an overall operation regarding reception of a packet copy activation / deactivation MAC CE by a UE according to an embodiment of the present disclosure;

[0044] Figure 2J is a diagram illustrating an operation for a UE to perform packet duplication according to an embodiment of the present disclosure;

[0045] Figure 2K is a diagram illustrating a UE operation when receiving ACK from one link while performing a packet copy UE operation and confirming successful delivery of a data packet of the packet copy according to an embodiment of the present disclosure;

[0046] Figure 2L is a diagram showing a configuration of a UE according to an embodiment of the present disclosure;

[0047] Figure 2M is a diagram showing a configuration of an eNB according to an embodiment of the present disclosure;

[0048] Figure 3A is a diagram showing a configuration of a next-generation mobile communication system according to an embodiment of the present disclosure;

[0049] Figure 3B is a diagram illustrating a protocol structure of a transmission phase and a reception phase for high-reliability, low-latency communication for a given traffic type / radio bearer according to an embodiment of the present disclosure;

[0050] Figure 3C is a diagram for illustrating a Radio Link Monitoring (RLM) operation in LTE technology according to an embodiment of the present disclosure;

[0051] Figure 3D is a diagram for illustrating a Radio Link Failure (RLF) operation in LTE technology according to an embodiment of the present disclosure;

[0052] Figure 3E is a diagram illustrating a first scheme for handling an RLC problem when a packet is copied and transmitted in a next-generation mobile communication system according to an embodiment of the present disclosure;

[0053] Figure 3F is a diagram illustrating a second scheme for handling an RLC problem when a packet is copied and transmitted in a next-generation mobile communication system according to an embodiment of the present disclosure;

[0054] Figure 3G is a diagram illustrating an operation of a UE processing an RLC problem when a packet is copied and transmitted in a next generation mobile communication system according to an embodiment of the present disclosure;

[0055] Figure 3H is a diagram showing a configuration of a UE according to an embodiment of the present disclosure; and

[0056] Figure 3I is a diagram showing the configuration of an eNB according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0057] Discussed below Figures 1A to 3I The various embodiments used to describe the principles of the present disclosure in this patent document are for illustration only and should not be construed in any way to limit the scope of the present disclosure. Those skilled in the art will understand that the principles of the present disclosure can be implemented in any suitably arranged system or device.

[0058] Hereinafter, some embodiments of the present disclosure are described in detail with reference to the accompanying drawings. When describing the present disclosure, a detailed description of related known functions or configurations related to the present disclosure will be omitted if it is considered that the gist of the present disclosure is unnecessarily obscure. In addition, the terms to be described below have been defined by taking into account the functions in the present disclosure and may differ depending on the intention or practice of the user, operator. Therefore, each term should be defined based on the content of the entire specification. In the following description, for the convenience of description, terms for identifying access nodes, terms for representing network entities, terms for representing messages, terms for representing interfaces between network entities, and terms for representing various types of identity information have been shown. Therefore, the present disclosure is not limited to the following terms, and other terms representing targets with equivalent technical meanings may be used.

[0059] In the following, for the convenience of description, in the embodiments of the present disclosure, the 3GPP Long Term Evolution (3GPE) is used. rd The present invention relates to terms and names defined in the 3GPP Long Term Evolution (3GPP LTE) standard or terms and names modified according to the defined terms and names. However, the present invention is not limited to these terms and names and can be applied to systems based on other standards in the same manner.

[0060] Figure 1A is a diagram showing a configuration of an LTE system according to an embodiment of the present disclosure.

[0061] refer to Figure 1A The radio access network of the LTE system includes next-generation evolved Node Bs (hereinafter referred to as "eNBs," "Node Bs," or "base stations") 1a-05, 1a-10, 1a-15, and 1a-20, a Mobility Management Entity (MME) 1a-25, and a Serving Gateway (S-GW) 1a-30. User equipment (hereinafter referred to as "UE or terminal") 1a-35 accesses external networks through the eNBs 1a-05, 1a-10, 1a-15, and 1a-20, as well as the S-GW 1a-30.

[0062] exist Figure 1AIn the LTE system, eNB 1a-05, eNB 1a-10, eNB 1a-15, and eNB 1a-20 correspond to the Node Bs of the existing UMTS system. The eNBs are connected to the UEs 1a-35 via radio channels and perform more complex functions than the existing Node Bs. In the LTE system, all types of user traffic, including real-time services such as voice over IP (VoIP), over the Internet Protocol are served via shared channels. Therefore, equipment that performs scheduling by collecting status information such as buffer status, available transmit power status, and the channel status of the UE may be necessary. eNB 1a-05, eNB 1a-10, eNB 1a-15, and eNB 1a-20 are responsible for such equipment. Typically, one eNB controls multiple cells. For example, to implement a transmission rate of 100 Mbps, the LTE system uses orthogonal frequency division multiplexing (hereinafter referred to as "OFDM") as a radio access technology in a 20 MHz bandwidth. In addition, the LTE system adopts an adaptive modulation and coding (hereinafter referred to as "AMC") scheme that determines the modulation scheme and channel coding rate based on the UE's channel status. The S-GW 1a-30 provides data bearers and creates or removes data bearers under the control of the MME 1a-25. In addition to mobility management functions for UEs, the MME is responsible for various control functions and is connected to multiple eNBs.

[0063] Figure 1B is a diagram illustrating a radio protocol architecture in an LTE system according to an embodiment of the present disclosure.

[0064] refer to Figure 1B The LTE system's radio protocols in the UE and eNB include the Packet Data Convergence Protocol (PDCP) 1b-05 and 1b-40, the Radio Link Control (RLC) 1b-10 and 1b-35, and the Medium Access Control (MAC) 1b-15 and 1b-30, respectively. PDCP 1b-05 and PDCP 1b-40 are responsible for operations such as IP header compression and restoration. The main functions of PDCP 1b-05 and PDCP 1b-40 are summarized below.

[0065] -Header compression and decompression: ROHC only

[0066] -Transmission of user data

[0067] - In-sequence delivery of upper layer PDUs during PDCP re-establishment of RLC AM

[0068] - Reordering functionality (for split bearer in DC) (supports RLC AM only): PDCP PDU routing for transmission and PDCP-PDU reordering for reception)

[0069] -Duplicate detection of lower layer SDUs during PDCP re-establishment of RLC AM

[0070] - Retransmission of PDCP SDUs during handover and, for split bearers in DC, retransmission of PDCP PDUs for RLC AM during PDCP data recovery

[0071] -Encryption and decryption

[0072] - Timer-based SDU discard in uplink.

[0073] RLC 1b-10 and RLC 1b-35 reconfigure PDCP packet data units (PDUs) to the appropriate size and perform ARQ operations. The main functions of RLC are summarized as follows.

[0074] -Transmission of upper layer PDU

[0075] -ARQ function (error correction through ARQ (only for AM data transmission))

[0076] - Concatenation, segmentation, and reassembly of RLC SDUs (only for UM and AM data transmission)

[0077] - Re-segmentation of RLC data PDUs (for AM data transmission only)

[0078] - Reordering of RLC data PDUs (only for UM and AM data transmission)

[0079] -Duplicate detection (only for UM and AM data transmission)

[0080] -Protocol error detection (for AM data transmission only)

[0081] -RLC SDU discard (only for UM and AM data transmission)

[0082] -RLC reconstruction

[0083] MAC 1b-15, 1b-30 is connected to a plurality of RLC layer devices configured in one UE and performs operations of multiplexing RLC PDUs with MAC PDUs and demultiplexing RLC PDUs from MAC PDUs. The main functions of MAC are summarized as follows.

[0084] - Mapping between logical channels and transport channels

[0085] - MAC SDUs belonging to one or different logical channels are multiplexed into / demultiplexed from a Transport Block (TB), which is delivered to / from the physical layer on the transport channel

[0086] -Dispatch information report

[0087] - Error correction through HARQ

[0088] - Prioritization between logical channels of a UE

[0089] - Prioritize between UEs with dynamic scheduling

[0090] -MBMS service identification

[0091] -Transmission format selection

[0092] -filling

[0093] The physical layers 1b-20, 1b-25 perform operations of channel coding and modulating higher layer data, generating higher layer data into OFDM symbols, and sending OFDM symbols through a radio channel or demodulating OFDM symbols received through a radio channel, channel decoding OFDM symbols, and sending OFDM symbols to a higher layer.

[0094] Figure 1C is a diagram illustrating a configuration of a next-generation mobile communication system according to an embodiment of the present disclosure.

[0095] refer to Figure 1C The radio access network of the next generation mobile communication system includes a new radio node B (hereinafter referred to as "NR NB" or "base station") 1c-10 and a new radio core network (NR CN) 1c-05. A new radio user equipment (hereinafter referred to as "NR UE" or "terminal") 1c-15 accesses an external network through the NR NB 1c-10 and NR CN 1c-05.

[0096] exist Figure 1CIn the NR NB 1c-10, the NR NB corresponds to the evolved Node B (eNB) of the existing LTE system. The NR NB 1c-10 is connected to the NR UE 1c-15 through a radio channel and can provide excellent services compared to the existing Node B. Because all types of user traffic are served through shared channels, the next-generation mobile communication system requires equipment for performing scheduling by collecting status information such as buffer status, available transmission power status, and channel status of the UE. The NRNB 1c-10 is responsible for the equipment. Typically, one NR NB controls multiple cells. In order to implement ultra-high-speed data transmission compared to the existing LTE, the next-generation mobile communication system can have the existing maximum bandwidth or more, and can use OFDM to additionally graft beamforming technology as a radio access technology. In addition, the next-generation mobile communication system adopts an AMC scheme that determines the modulation scheme and channel coding rate based on the channel status of the UE. The NR CN 1c-05 performs functions such as mobility support, bearer configuration, and QoS configuration. The NR CN 1c-05 is responsible for various control functions, in addition to UE mobility management, and is connected to multiple eNBs. Furthermore, the next-generation mobile communication system can also operate in conjunction with the existing LTE system. The NR CN is connected to the MME 1c-25 via a network interface. The MME 1c-25 is connected to the eNB 1c-30, which is an existing eNB.

[0097] Figure 1D is a diagram illustrating a radio protocol architecture of a next generation mobile communication system according to an embodiment of the present disclosure.

[0098] refer to Figure 1D The radio protocols of the next-generation mobile communication system include NR PDCP 1d-05 and NR PDCP 1d-40 in the UE and NR NB, NR RLC 1d-10 and NR RLC 1d-35, and NR MAC 1d-15 and NR MAC 1d-30, respectively. The main functions of NR PDCP 1d-05 and NR PDCP 1d-40 may include some of the following functions.

[0099] -Header compression and decompression: ROHC only

[0100] -Transmission of user data

[0101] - In-sequence delivery of upper layer PDUs

[0102] - Out-of-sequence delivery of upper layer PDUs

[0103] - Reorder PDCP PDUs for reception

[0104] - Duplicate detection of lower layer SDUs

[0105] -Retransmission of PDCP SDU

[0106] -Encryption and decryption

[0107] - Timer-based SDU discard in uplink.

[0108] The reordering function of the NR PDCP device refers to the function of sequentially reordering PDCP PDUs received from lower layers based on the PDCP sequence number (SN). The reordering function may include the function of sending data to higher layers in a reordered sequence or directly sending data to higher layers without considering the order, the function of reordering the sequence and recording lost PDCP PDUs, the function of reporting the status of lost PDCP PDUs to the transmitting side, and the function of requesting the retransmission of lost PDCP PDUs. The main functions of NR RLC 1d-10 and NR RLC 1d-35 may include some of the following functions.

[0109] -Transmission of upper layer PDU

[0110] - In-sequence delivery of upper layer PDUs

[0111] - Out-of-sequence delivery of upper layer PDUs

[0112] - Error correction through ARQ

[0113] - Concatenation, segmentation and reassembly of RLC SDUs

[0114] - Re-segmentation of RLC data PDUs

[0115] -Reordering of RLC data PDUs

[0116] -Duplicate detection

[0117] -Protocol error detection

[0118] -RLC SDU discarded

[0119] -RLC reconstruction

[0120] The in-sequence delivery function of the NR RLC device refers to a function of sequentially transmitting RLC SDUs received from a lower layer to a higher layer, and may include a function of reassembling and transmitting a plurality of RLC SDUs if one RLC SDU has been originally segmented into a plurality of RLC SDUs and received. The in-sequence delivery function may include a function of reordering received RLC PDUs based on an RLC sequence number (SN) or a PDCP sequence number (SN); a function of reordering the order and recording lost RLC PDUs; a function of transmitting a status report about lost RLC PDUs to a transmitting side; a function of requesting retransmission of lost RLC PDUs; a function of sequentially transmitting only the RLC SDUs preceding the lost RLC SDU to a higher layer when a lost RLC SDU occurs; a function of sequentially transmitting all RLC SDUs received until the expiration of a given timer to a higher layer when there is a lost RLC SDU; and a function of sequentially transmitting all RLC SDUs received so far to a higher layer when a given timer expires when there is a lost RLC SDU. In addition, the in-sequence delivery function may include the function of processing RLC PDUs in the order in which they are received (in the order of arrival, regardless of the order of sequence number and sequence number) and sending RLC PDUs to the PDCP device regardless of their order (i.e., out-of-sequence delivery). The in-sequence delivery function may include the function of receiving segments stored in the buffer or segments to be received later, reconfiguring segments in a complete RLC PDU, processing RLC PDUs, and sending RLC PDUs to the PDCP device. The NR RLC layer may not include a concatenation function. The concatenation function may be performed by the NR MAC layer or may be replaced by a multiplexing function of the NR MAC layer.

[0121] The out-of-sequence delivery function of the NR RLC device refers to a function of directly sending RLC SDUs received from a lower layer to a higher layer regardless of their order. The out-of-sequence delivery function may include a function of reassembling multiple RLC SDUs if one RLC SDU has been originally segmented into multiple RLC SDUs and received. The out-of-sequence delivery function may include a function of storing the RLC SN or PDCP SN of received RLC PDUs, reordering their order, and recording lost RLC PDUs.

[0122] NR MAC 1d-15, NR MAC 1d-30 can be connected to multiple NR RLC layer devices configured in one UE. The main functions of NR MAC may include some of the following functions.

[0123] - Mapping between logical channels and transport channels

[0124] -Multiplexing / demultiplexing of MAC SDUs

[0125] -Dispatch information report

[0126] - Error correction through HARQ

[0127] - Prioritization between logical channels of a UE

[0128] - Prioritize between UEs with dynamic scheduling

[0129] -MBMS service identification

[0130] -Transmission format selection

[0131] -filling

[0132] NR PHY layers 1d-20 and NR PHY layers 1d-25 may perform operations of channel coding and modulating higher layer data, generating higher layer data into OFDM symbols, and sending OFDM symbols to a radio channel or demodulating OFDM symbols received through a radio channel, channel decoding OFDM symbols, and transmitting OFDM symbols to a higher layer.

[0133] Figure 1E is a diagram illustrating a structure of a COUNT value in LTE according to an embodiment of the present disclosure.

[0134] In PDCP, a value called "COUNT" is stored for ciphering and integrity protection between the UE and the eNB. When performing ciphering and integrity protection of PDCP packets, the stored COUNT value is used as a parameter of the previously configured ciphering and integrity protection algorithm. Figure 1F Give a detailed description.

[0135] All PDCP packets (e.g., data packets and control message packets) have a PDCP sequence number (SN), and each PDCP packet may have a value that increases by 1 from the previous value when the packet is generated. When the preset PDCP SN size is exceeded, the PDCP SN will be counted again from 0. In this case, the PDCP SN may have the same SN as the previously transmitted PDCP packet. If a hacker has a previous SN value and attempts to use the corresponding value to hack during communication between the UE and the eNB, the communication may be affected by the added PDCP packet. The UE and eNB have introduced the COUNT value to address security issues that may occur due to the limited SN length. The COUNT value has a length of 32 bits and includes the Hyperframe Number (HFN) 1e-05 and the PDCP SN 1e-10. The UE and eNB can maintain the COUNT value and use it for encryption and integrity protection. During actual data transmission, the PDCP packet only includes the SN. Therefore, it is difficult for a hacker to know the exact COUNT value because only the PDCP SN is transmitted over the radio channel. For reference, the PDCP SN used in LTE has multiple values as shown in Table 1-1 1e-15.

[0136] Table 1-1: PDCP SN length

[0137] length describe 5 SRB 7 DRB (if configured by upper layer) (pdcp-SN-size) 12 DRB (if configured by upper layer) (pdcp-SN-size) 15 DRB (if configured by upper layer) (pdcp-SN-size) 16 SLRB 18 DRB (if configured by upper layer) (pdcp-SN-size)

[0138] When the eNB configures the PDCP configuration for the UE via an RRC message, it sets the PDCP SN size to 5, 7, 12, 15, 16, and 18 bits, and can automatically generate the COUNT value based on the set value. In other words, the HFN size is implicitly determined (1e-20).

[0139] Figure 1F : is a diagram illustrating an encryption process in access stratum (AS) security of an LTE system, in order to describe an example of using the COUNT value of the present disclosure.

[0140] Figure 1F The following diagram shows a series of processes for encrypting the uplink data of a user generated in the UE, transmitting the data to the eNB, and decrypting the data. In this case, the downlink encryption / decryption operation is also the same, and thus in Figure 1FNot shown in the figure. In LTE, all packets are sent in their unencrypted state until AS security is activated, and all types of traffic (control plane (CP) and user plane (UP) data) are encrypted and sent after AS security is activated. That is, when the UE and eNB exchange SecurityModeCommand messages and SecurityModeComplete messages and security configuration is completed, all RRC messages exchanged between the UE and eNB are integrity protected and encrypted and sent, and IP packets are encrypted and sent.

[0141] After AS security is established, when uplink data from the UE occurs (1f-05), a keystream block is obtained using the UE's encryption key generation algorithm (EPS encryption algorithm) 1f-15, and the pure uplink data block (i.e., the plaintext block) is subjected to an exclusive OR operation 1f-20 to generate an encrypted user packet. In this case, the keystream block for encryption can be obtained by executing a key generation algorithm using the user plane encryption key (K_UP_enc) 1f-10 obtained from the K_eNB and input parameters such as COUNT (32-bit uplink NASCOUNT value), bearer (bearer ID), direction (message transmission direction, 0: uplink, 1: downlink), and length (length of the keystream block). The eNB receives the user packet encrypted by the UE, generates the same keystream block used for encryption by executing the key generation algorithm applied in the UE, and performs an exclusive OR operation (1f-35). As in the execution of the algorithm in the UE, the eNB can obtain the key stream block for encryption using the encryption key (K_UP_enc) 1f-25 for the user plane obtained from K_eNB and parameters such as COUNT (32-bit up NAS COUNT value), bearer (bearer ID), direction (message transmission direction, 0: uplink, 1: downlink) and length (length of the key stream block) (1f-30) as input. The receiving stage can perform selective decryption by applying the encryption operation in reverse in the transmitting stage.

[0142] In order to accurately perform the encryption process, the COUNT value held by the UE and the eNB must be accurate. That is, in order to apply the accurate encryption key to the PDCP packet to be encrypted, a process of checking whether the COUNT value is accurate may be necessary. To this end, LTE includes an operation for the eNB to request the UE to perform a COUNT CHECK. In response to the request from the eNB, the UE determines the suitability of the COUNT value, and if it is determined that the COUNT value is not suitable, it sends the COUNT value to the eNB. Reference Figure 1G Give a detailed description.

[0143] Figure 1G is a diagram illustrating a COUNT CHECK operation in LTE according to an embodiment of the present disclosure.

[0144] Figure 1G The entire operation of the eNB checking the UE's COUNT value is shown. The eNB can identify whether the COUNT value of each configured DRB is valid through the corresponding operation.

[0145] First, when UE 1g-01 and eNB 1g-02 are RRC connected (1g-05), the eNB requests a COUNT check and report for each DRB from the UE by sending a CounterCheck RRC message to the UE (1g-10). This message is sent over a dedicated common control channel (DCCH) and can be sent as an RRCConnectionReconfiguration or RRCConnectionReestablishment message. In addition, the CounterCheck message sends a list drb-CountMSB-InfoList for requesting a COUNT check for each DRB. The list includes a drb identifier, countMSB-Uplink (25 bits), and countMSB-Downlink (25 bits). That is, the list includes the identifier of the DRB on which the COUNT check needs to be performed and the MSB 25 bits of the uplink and downlink COUNT values that the eNB has in the corresponding DRB.

[0146] After receiving the message, the UE compares the 25-bit MSB stored in the UE with the 25-bit MSB of the configured DRB (i.e., performs both countMSB-Uplink and countMSB-Downlink, i.e., the values for uplink and downlink). The UE generates a message to report the complete COUNT (32 bits) for DRBs with different MSB values (1g-15). In addition, the UE generates a message to report to the eNB the complete COUNT for DRBs that are not included in the DRB list of the received CounterCheck message (1g-15). If the COUNT value received from the eNB and the COUNT value calculated by the UE are the same, the corresponding DRB is excluded from the report list. Thereafter, the UE sends the CounterCheckResponse message generated at operation 1g-15 to the eNB (1g-20).

[0147] Figure 1His a diagram illustrating an entire COUNT CHECK operation in a next generation mobile communication system according to an embodiment of the present disclosure.

[0148] When UE 1h-01 and eNB 1h-02 are RRC connected (1h-05), the eNB requests a COUNT check and report for each DRB from the UE by sending a CounterCheckRRC message to the UE (1h-10). This message is sent over a dedicated common control channel (DCCH) and can be sent as an RRCConnectionReconfiguration or RRCConnectionReestablishment message. In addition, the CounterCheck message sends a list drb-CountMSB-InfoList for requesting a COUNT check for each DRB. The list includes a drb identifier, countMSB-Uplink (25 bits), and countMSB-Downlink (25 bits). That is, the list includes the identifier of the DRB on which the COUNT check needs to be performed and the MSB 25 bits of the uplink and downlink COUNT values that the eNB has in the corresponding DRB. However, the eNB can send the CounterCheck message over SRB1 or SRB3. That is, if the UE is connected to the MCG, the UE can receive the COUNT CHECK request through the MCG SRB. If the UE is connected to the SCG, it can receive the COUNT CHECK request through the SCG SRB. In addition, the UE can receive the COUNT CHECK request of SRB1 and SRB3 at the same time.

[0149] After receiving the message, the UE checks whether the bearer on which the CounterCheck message has been received is SRB1 or SRB3, and then performs the following operations (1h-15).

[0150] 1. When SRB1 is received (first operation): generate a COUNT CHECK RESPONSE message including the complete COUNT of the first DRB group and the third DRB group;

[0151] 2. When SRB3 is received (second operation): generate a COUNT CHECK RESPONSE message including the complete COUNT of the second and third DRB groups;

[0152] In this case, the definition of the DRB group used in the first operation and the second operation is as follows.

[0153] - First DRB group: a set of DRBs belonging to MCG bearers and MCG split bearers but not included in drb-CountMSB-InfoList;

[0154] - Second DRB group: a set of DRBs belonging to SCG bearers and SCG split bearers but not included in drb-CountMSB-InfoList;

[0155] - Third DRB group: a set of DRBs that belong to the DRBs included in drb-CountMSB-InfoList and do not have the same 25 MSB bits;

[0156] For example, when a CounterCheck message is received via SRB1, the UE receives the complete COUNT value of DRBs belonging to MCG bearers and MCG split bearers but not included in the drb-CountMSB-InfoList; compares the 25-bit MSB of the DRB configured in the received CounterCheck message with the 25-bit MSB stored in the UE (i.e., performs both countMSB-Uplink and countMSB-Downlink, i.e., the values for uplink and downlink); and stores the complete COUNT value of DRBs with different MSB values. If the COUNT value received from the eNB and the COUNT value calculated by the UE are the same, the UE excludes the corresponding DRB from the report list.

[0157] In this case, when comparing COUNT values, it may be necessary for the UE to figure out which PDCP SDU's COUNT value the values set in the CounterCheck message (countMSB-Uplink (25 bits) and countMSB-Downlink (25 bits)) will be compared with. The UE can apply the following two methods.

[0158] - compared with the highest COUNT (NEXT_RX_COUNT-1) of one of the PDCP SDUs received so far;

[0159] - or compared with the highest COUNT of PDCP SDUs that have completed reordering;

[0160] In addition, the UE needs to define which PDCP SDU COUNT will be reported. The UE can apply the following three methods.

[0161] - COUNT report that is the same as the compared COUNT;

[0162] - or the highest COUNT at the reporting time;

[0163] - or the highest COUNT of PDCP SDUs that have completed reordering at the reporting time;

[0164] When the UE generates result information about the CounterCheck in the above operation, it transmits an RRC message (CounterCheckResponse) including the corresponding information to the eNB (1h-20).

[0165] Figure 1I is a diagram illustrating UE operation according to an embodiment of the present disclosure.

[0166] When the UE receives a COUNT CHECK request (RRC message) from the eNB (1i-05), the UE identifies the SRB through which the RRC message has been sent (1i-10). If the UE receives the RRC message through SRB1 (SRB of the MCG), the UE performs the first operation. If the UE receives the RRC message through SRB3 (SRB of the SCG), the UE performs the second operation.

[0167] The first operation of the UE is a method of performing COUNT CHECK on the first DRB group and the third DRB group when performing COUNT CHECK. The first DRB group means a set of DRBs that belong to the MCG bearer and the MCG split bearer but are not included in the received drb-CountMSB-InfoList. The third DRB group means a set of DRBs that belong to the DRBs included in the received drb-CountMSB-InfoList. That is, the UE performs a COUNT CHECK operation on the DRB list included in the third DRB group (i.e., compares the 25-bit MSB of the DRB configured in the CounterCheck message with the 25-bit MSB stored in the UE) (i.e., performs both countMSB-Uplink and countMSB-Downlink, i.e., for the uplink and downlink values) and stores the UE's complete COUNT value (1i-15) for DRBs with different MSB values. The UE stores the complete COUNT of the first DRB group and generates a COUNT CHECK RESPONSE message (1i-20). Thereafter, the UE sends the generated COUNT CHECK RESPONSE message to the eNB (1i-25).

[0168] The second operation of the UE is a method of performing COUNTCHECK on the second DRB group and the third DRB group when performing COUNT CHECK. The second DRB group means a set of DRBs that belong to the SCG bearer and the SCG separate bearer but are not included in the received drb-CountMSB-InfoList. The third DRB group means a set of DRBs included in the received drb-CountMSB-InfoList. That is, the UE performs a COUNTCHECK operation on the DRB list included in the third DRB group (i.e., compares the 25-bit MSB of the DRB configured in the CounterCheck message with the 25-bit MSB stored in the UE) (i.e., performs both countMSB-Uplink and countMSB-Downlink, i.e., for the uplink and downlink values) and stores the UE's complete COUNT value (1i-30) for DRBs with different MSB values. The UE stores the complete COUNT of the second DRB group and generates a COUNT CHECK RESPONSE message (1i-35). If the COUNT value received from the eNB is the same as the COUNT value calculated by the UE, the UE excludes the corresponding DRB from the report list. Thereafter, the UE sends the generated COUNT CHECK RESPONSE message to the eNB (1i-40).

[0169] As reference Figure 1H As described, when comparing COUNT values, the UE may need to figure out which PDCP SDU's COUNT value the values (countMSB-Uplink (25 bits) and countMSB-Downlink (25 bits)) set in the CounterCheck message will be compared with. The UE may apply the following two methods.

[0170] - Compare with the highest COUNT of PDCP SDUs received so far (NEXT_RX_COUNT-1);

[0171] - or compared with the highest COUNT of PDCP SDUs that have completed reordering;

[0172] In addition, it may be necessary for the UE to define which PDCP SDU COUNT will be reported. The UE can apply the following three methods.

[0173] - the same COUNT report as the COUNT of the compared COUNT and;

[0174] - or the highest COUNT at the reporting time;

[0175] - or the highest COUNT of PDCP SDUs that have completed reordering at the reporting time.

[0176] Figure 1J is a diagram illustrating a configuration of a UE according to an embodiment of the present disclosure.

[0177] refer to Figure 1J , the UE includes a radio frequency (RF) processor 1j-10, a baseband processor 1j-20, a storage unit 1j-30 and a controller 1j-40.

[0178] The RF processor 1j-10 performs functions for sending / receiving signals through a radio channel, such as frequency band conversion and amplification of the signal. That is, the RF processor 1j-10 up-converts the baseband signal received from the baseband processor 1j-20 into an RF band signal, transmits the RF band signal through an antenna, and down-converts the RF band signal received through the antenna into a baseband signal. For example, the RF processor 1j-10 may include a transmitting filter, a receiving filter, an amplifier, a mixer, an oscillator, a digital-to-analog converter (DAC), and an analog-to-digital converter (ADC). Figure 1J In the figure, only one antenna is shown, but the UE may include multiple antennas. In addition, the RF processor 1j-10 may include multiple RF chains. In addition, the RF processor 1j-10 may perform beamforming. For beamforming, the RF processor 1j-10 may adjust the phase and magnitude of each of the signals transmitted / received through multiple antennas or antenna elements. In addition, the RF processor may perform MIMO. When performing MIMO operation, the RF processor may receive multiple layers.

[0179] The baseband processor 1j-20 performs the conversion function between the baseband signal and the bit stream based on the physical layer standard of the system. For example, when sending data, the baseband processor 1j-20 generates complex symbols by encoding and modulating the sending bit stream. In addition, when receiving data, the baseband processor 1j-20 reconstructs the received bit stream from the baseband signal by modulation and demodulation, and the baseband signal is received from the RF processor 1j-10. For example, if the OFDM scheme is applied, when sending data, the baseband processor 1j-20 generates complex symbols by encoding and modulating the sending bit stream, maps the complex symbols to subcarriers, and then configures OFDM symbols through IFFT operation and CP insertion. In addition, when receiving data, the baseband processor 1j-20 segments the baseband signal received from the RF processor 1j-10 in OFDM symbol units, reconstructs the signal mapped to the subcarriers through FFT operation, and reconstructs the received bit stream through modulation and demodulation.

[0180] As described above, the baseband processor 1j-20 and the RF processor 1j-10 send and receive signals. Therefore, the baseband processor 1j-20 and the RF processor 1j-10 can be referred to as a transmitter, a receiver, a transceiver or a communication unit. In addition, at least one of the baseband processor 1j-20 and the RF processor 1j-10 may include a plurality of communication modules to support different multiple radio access technologies. In addition, at least one of the baseband processor 1j-20 and the RF processor 1j-10 may include different communication modules to process signals of different frequency bands. For example, different radio access technologies may include wireless LAN (e.g., IEEE 802.11) and cellular networks (e.g., LTE). In addition, different frequency bands may include ultra-high frequency (SHF) (e.g., 2.NRHz, NRhz) bands and millimeter wave (e.g., 60GHz) bands.

[0181] The storage unit 1j-30 stores basic programs, applications, and data such as configuration information for the operation of the UE. Specifically, the storage unit 1j-30 can store information related to a second access node that performs wireless communication using a second radio access technology. In addition, the storage unit 1j-30 provides the stored data in response to a request from the controller 1j-40. Specifically, with respect to the present disclosure, the storage unit 1j-30 stores and updates a COUNT value.

[0182] The controller 1j-40 controls the overall operation of the UE. For example, the controller 1j-40 sends / receives signals through the baseband processor 1j-20 and the RF processor 1j-10. In addition, the controller 1j-40 writes data to / reads data from the memory unit 1j-30. Specifically, with respect to the present disclosure, the controller 1j-40 writes a COUNT value to / reads a COUNT value from the memory unit 1j-30. To this end, the controller 1j-40 may include at least one processor. For example, the controller 1j-40 may include a communication processor (CP) that performs communication control and an application processor (AP) that controls a higher layer (such as an application).

[0183] Figure 1K is a diagram showing the configuration of an eNB according to an embodiment of the present disclosure.

[0184] like Figure 1K As shown, the eNB includes an RF processor 1k-10, a baseband processor 1k-20, a backhaul communication unit 1k-30, a storage unit 1k-40, and a controller 1k-50.

[0185] The RF processor 1k-10 performs functions for transmitting / receiving signals through a radio channel, such as frequency band conversion and amplification of the signals. That is, the RF processor 1k-10 up-converts the baseband signal received from the baseband processor 1k-20 into an RF band signal, transmits the RF band signal through an antenna, and down-converts the RF band signal received through the antenna into a baseband signal. For example, the RF processor 1k-10 may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a DAC, and an ADC. Figure 1K In the figure, only one antenna is shown, but the eNB may include multiple antennas. In addition, the RF processor 1k-10 may include multiple RF chains. In addition, the RF processor 1k-10 may perform beamforming. For beamforming, the RF processor 1k-10 may adjust the phase and magnitude of each of the signals transmitted / received through multiple antennas or antenna elements. The RF processor may perform downlink MIMO operations by transmitting one or more layers.

[0186] The baseband processor 1k-20 performs the conversion function between baseband signals and bit streams based on the physical layer standard of the first radio access technology. For example, when sending data, the baseband processor 1k-20 generates complex symbols by encoding and modulating the transmitted bit stream. In addition, when receiving data, the baseband processor 1k-20 reconstructs the received bit stream from the baseband signal by modulation and demodulation, and the baseband signal is received from the RF processor 1k-10. For example, if the OFDM scheme is applied, when sending data, the baseband processor 1k-20 generates complex symbols by encoding and modulating the transmitted bit stream, maps the complex symbols to subcarriers, and then configures OFDM symbols through IFFT operation and CP insertion. In addition, when receiving data, the baseband processor 1k-20 segments the baseband signal received from the RF processor 1k-10 in OFDM symbol units, reconstructs the signal mapped to the subcarriers through FFT operation, and then reconstructs the received bit stream through modulation and demodulation. As described above, the baseband processor 1k-20 and the RF processor 1k-10 send and receive signals. Therefore, the baseband processor 1k-20 and the RF processor 1k-10 can be referred to as a transmitter, a receiver, a transceiver, a communication unit, or a wireless communication unit.

[0187] The backhaul communication unit 1k-30 provides an interface for performing communication with other nodes within the network. That is, the backhaul communication unit 1k-30 converts the bit stream sent from the master eNB to different nodes (e.g., auxiliary eNB or core network) into a physical signal, and converts the physical signal received from the different nodes into a bit stream.

[0188] The storage unit 1k-40 stores data such as basic programs, applications, and configuration information for the operation of the master eNB. Specifically, the storage unit 1k-40 can store information about bearers allocated to accessed UEs and measurement results reported by accessed UEs. In addition, the storage unit 1k-40 can store information, namely, criteria for determining whether to provide dual connectivity to the UE or to stop dual connectivity. In addition, the storage unit 1k-40 provides the stored data in response to a request from the controller 1k-50.

[0189] The controller 1k-50 controls the overall operation of the master eNB. For example, the controller 1k-50 transmits / receives signals via the baseband processor 1k-20 and the RF processor 1k-10, or via the backhaul communication unit 1k-30. Furthermore, the controller 1k-50 writes data to the memory unit 1k-40 and reads data from the memory unit 1k-40. Specifically, with respect to the present disclosure, the controller 1k-50 writes / reads a COUNT value to / from the memory unit 1k-40. To this end, the controller 1k-50 may include at least one processor.

[0190] Another embodiment of the present disclosure relates to a method and apparatus for activating and deactivating packet duplication in a next generation mobile communication system.

[0191] Figure 2A is a diagram showing a configuration of an LTE system according to an embodiment of the present disclosure.

[0192] refer to Figure 2A The radio access network of the LTE system includes next-generation evolved Node Bs (hereinafter referred to as "eNBs," "Node Bs," or "base stations") 2a-05, 2a-10, 2a-15, and 2a-20, a mobility management entity (MME) 2a-25, and a serving gateway (S-GW) 2a-30. User equipment (hereinafter referred to as "UE" or "terminal") 2a-35 accesses external networks through the eNBs 2a-05, 2a-10, 2a-15, 2a-20, and the S-GW 2a-30.

[0193] exist Figure 2AIn the LTE system, eNB 2a-05, eNB 2a-10, eNB 2a-15, and eNB 2a-20 correspond to the Node Bs of the existing UMTS system. The eNBs are connected to the UE 2a-35 via radio channels and perform more complex functions than the existing Node Bs. In the LTE system, all types of user traffic, including real-time services, such as voice over IP (VoIP), via the Internet Protocol are served via shared channels. Therefore, equipment that performs scheduling by collecting status information such as buffer status, available transmit power status, and the channel status of the UE may be necessary. eNB 2a-05, eNB 2a-10, eNB 2a-15, and eNB 2a-20 are responsible for such equipment. Typically, one eNB controls multiple cells. For example, to implement a transmission rate of 100 Mbps, the LTE system uses OFDM as the radio access technology in a 20 MHz bandwidth. In addition, the LTE system adopts an AMC scheme that determines the modulation scheme and channel coding rate based on the channel status of the UE. The S-GW 2a-30 provides data bearers and generates or removes data bearers under the control of the MME 2a-25. In addition to the mobility management function for the UE, the MME is also responsible for various control functions and is connected to multiple eNBs.

[0194] Figure 2B is a diagram illustrating a radio protocol architecture in an LTE system according to an embodiment of the present disclosure.

[0195] refer to Figure 2B The LTE system's radio protocols in the UE and eNB include the Packet Data Convergence Protocol (PDCP) 2b-05 and 2b-40, the Radio Link Control (RLC) 2b-10 and 2b-35, and the Medium Access Control (MAC) 2b-15 and 2b-30, respectively. PDCP 2b-05 and PDCP 2b-40 are responsible for operations such as IP header compression and restoration. The main functions of PDCP 2b-05 and PDCP 2b-40 are summarized below.

[0196] -Header compression and decompression: ROHC only

[0197] -Transmission of user data

[0198] - In-sequence delivery of upper layer PDUs during PDCP re-establishment of RLC AM

[0199] - Reordering functionality (for split bearers in DC (supports RLC AM only): PDCP PDU routing for transmission and PDCP-PDU reordering for reception)

[0200] - Duplicate detection of lower layer SDUs during PDCP re-establishment of RLC AM

[0201] - Retransmission of PDCP SDUs during handover and, for split bearers in DC, retransmission of PDCP PDUs for RLC AM during PDCP data recovery

[0202] -Encryption and decryption

[0203] - Timer-based SDU discard in uplink.

[0204] RLC 2b-10 and RLC 2b-35 reconfigure PDCP packet data units (PDUs) to the appropriate size and perform ARQ operations. The main functions of RLC are summarized as follows.

[0205] -Transmission of upper layer PDU

[0206] -ARQ function (error correction through ARQ (only for AM data transmission))

[0207] - Concatenation, segmentation, and reassembly of RLC SDUs (only for UM and AM data transmission)

[0208] - Re-segmentation of RLC data PDUs (for AM data transmission only)

[0209] - Reordering of RLC data PDUs (only for UM and AM data transmission)

[0210] -Duplicate detection (only for UM and AM data transmission)

[0211] -Protocol error detection (for AM data transmission only)

[0212] -RLC SDU discard (only for UM and AM data transmission)

[0213] -RLC reconstruction

[0214] MAC 2b-15, 2b-30 is connected to a plurality of RLC layer devices configured in one UE and performs operations of multiplexing RLC PDUs with MAC PDUs and demultiplexing RLC PDUs from MAC PDUs. The main functions of MAC are summarized as follows.

[0215] - Mapping between logical channels and transport channels

[0216] - MAC SDUs belonging to one or different logical channels are multiplexed into / demultiplexed from a transport block, which is delivered to / from the physical layer on the transport channel

[0217] -Dispatch information report

[0218] - Error correction through HARQ

[0219] - Prioritization between logical channels of a UE

[0220] - Prioritize between UEs with dynamic scheduling

[0221] -MBMS service identification

[0222] -Transmission format selection

[0223] -filling

[0224] The physical layers 2b-20, 2b-25 perform operations of channel coding and modulating higher layer data, generating higher layer data into OFDM symbols, and sending OFDM symbols through a radio channel or demodulating OFDM symbols received through a radio channel, channel decoding OFDM symbols, and sending OFDM symbols to a higher layer.

[0225] Figure 2C is a diagram schematically illustrating dual connectivity and carrier operations in an LTE system according to an embodiment of the present disclosure.

[0226] refer to Figure 2C Assuming that eNB 1 2c-05 transmits / receives a carrier with a center frequency of f1 and eNB 2 2c-15 transmits / receives a carrier with a center frequency of f2, when UE 1 2c-01 combines the carrier with a forward center frequency of f1 and the carrier with a forward center frequency of f2, one UE can transmit / receive data to / from two or more eNBs. The LTE system supports such an operation, which is called dual connectivity (hereinafter referred to as "DC").

[0227] Furthermore, typically, a single eNB 3 2c-25 can transmit / receive multiple carriers in multiple frequency bands. For example, in conventional technology, when eNB 3 2c-25 transmits carrier 2c-30 with a forward center frequency of f3 and carrier 2c-35 with a forward center frequency of f4, a single UE uses one of the two carriers to transmit / receive data. However, a UE 2 2c-40 with carrier aggregation capabilities can simultaneously transmit / receive data via multiple carriers. eNB 3 2c-25 can allocate more carriers to UE 2 2c-40 with carrier aggregation capabilities as needed, thereby increasing the transmission rate of UE 2 2c-40. Aggregating forward and reverse carriers transmitted and received by a single eNB as described above is called intra-eNB carrier aggregation (CA). In the conventional sense, assuming that one forward carrier transmitted by an eNB and one reverse carrier received by the same eNB form a single cell, carrier aggregation can be understood as a UE simultaneously transmitting / receiving data via multiple cells. Therefore, the maximum transmission rate increases in proportion to the number of aggregated carriers.

[0228] In the following embodiments of the present invention, the meaning of a UE receiving data through a specific forward carrier or sending data through a specific uplink carrier is the same as the meaning of sending / receiving data using a control channel and a data channel provided by a cell corresponding to the center frequency and frequency band characterizing the carrier. In an embodiment of the present disclosure, a set of service cells controlled by the same eNB is defined as a cell group (CG). The cell group is divided into a master cell group (MCG) and a secondary cell group (SCG). MCG means a set of service cells controlled by an eNB (i.e., master eNB (MeNB)) that controls a primary cell (PCell). SCG means a set of service cells controlled by an eNB other than the eNB that controls a PCell (i.e., an eNB that controls only a secondary cell (SCell) (i.e., secondary eNB (SeNB))). The eNB informs the UE whether a given service cell belongs to an MCG or an SCG during the process of configuring the corresponding service cell.

[0229] PCell and SCell are terms indicating the type of service cell configured in the UE. PCell and SCell have some differences. For example, PCell maintains an activation state, but SCell repeats an activation state and a deactivation state in response to an instruction from the eNB. The mobility of the UE is controlled based on the PCell, and the SCell can be understood as an additional service cell for data transmission / reception. In an embodiment of the present disclosure, PCell and SCell mean the PCell and SCell defined in LTE standards 36.331 or 36.321. The terms have the same meanings as those used in the LTE mobile communication system without any changes. In one embodiment of the present disclosure, terms such as carrier, component carrier, and service cell are used interchangeably.

[0230] Return Reference Figure 2C , if eNB 1 2c-05 is a MeNB and eNB 2 2c-15 is a SeNB, the service cell 2c-10 with the center frequency f1 is a service cell belonging to the MCG, and the service cell 2c-20 with the center frequency f2 is a service cell belonging to the SCG. In addition, it is actually impossible to send the HARQ feedback and channel state information (hereinafter referred to as "CSI") of the SCG SCell through the Physical Uplink Control Channel (PUCCH) of the PCell. The HARQ feedback needs to be sent within the HARQ Round Trip Time (RTT) (typically 8ms). This is because the transmission delay between the MeNB and the SeNB may be longer than the HARQ RTT. Due to this problem, PUCCH transmission resources are configured in one of the SCells belonging to the SCG (i.e., the primary SCell (PSCell)), and the HARQ feedback and CSI of the SCG SCell are sent through the PUCCH.

[0231] Furthermore, in public carrier aggregation within eNB 3 2c-25, UE 2 2c-40 transmits HARQ feedback and CSI for the SCell in addition to the HARQ feedback and CSI for the PCell via the PCell's PUCCH. This is because carrier aggregation is applied to UEs that are not capable of simultaneous uplink transmission. LTE Rel-13 enhanced carrier aggregation (eCA) defines additional SCells with PUCCH, and can aggregate up to 32 carriers.

[0232] Figure 2D is a diagram illustrating a radio protocol architecture of a next generation mobile communication system according to an embodiment of the present disclosure.

[0233] refer to Figure 2D The radio protocols of the next-generation mobile communication system include NR PDCP 2d-05 and NR PDCP 2d-40 in the UE and NR NB, NR RLC 2d-10 and NR RLC 2d-35, and NR MAC 2d-15 and NR MAC 2d-30, respectively. The main functions of NR PDCP 2d-05 and NR PDCP 2d-40 may include some of the following functions.

[0234] -Header compression and decompression: ROHC only

[0235] -Transmission of user data

[0236] - In-sequence delivery of upper layer PDUs

[0237] - Out-of-sequence delivery of upper layer PDUs

[0238] - Reorder PDCP PDUs for reception

[0239] - Duplicate detection of lower layer SDUs

[0240] -Retransmission of PDCP SDU

[0241] -Encryption and decryption

[0242] - Timer-based SDU discard in uplink.

[0243] The reordering function of the NR PDCP device refers to the function of sequentially reordering PDCP PDUs received from lower layers based on the PDCP sequence number (SN). The reordering function may include the function of sending data to higher layers in a reordered sequence or directly sending data to higher layers without considering the order, the function of reordering the order and recording lost PDCP PDUs, the function of reporting the status of lost PDCP PDUs to the transmitting side, and the function of requesting retransmission of lost PDCP PDUs.

[0244] The main functions of NR RLC 2d-10, NR RLC 2d-35 may include some of the following functions.

[0245] -Transmission of upper layer PDU

[0246] - In-sequence delivery of upper layer PDUs

[0247] - Out-of-sequence delivery of upper layer PDUs

[0248] - Error correction through ARQ

[0249] - Concatenation, segmentation and reassembly of RLC SDUs

[0250] - Re-segmentation of RLC data PDUs

[0251] -Reordering of RLC data PDUs

[0252] -Duplicate detection

[0253] -Protocol error detection

[0254] -RLC SDU discarded

[0255] -RLC reconstruction

[0256] The in-sequence delivery function of the NR RLC device refers to a function of sequentially transmitting RLC SDUs received from a lower layer to a higher layer, and may include a function of reassembling and transmitting a plurality of RLC SDUs if one RLC SDU has been originally segmented into a plurality of RLC SDUs and received. The in-sequence delivery function may include: a function of reordering received RLC PDUs based on an RLC sequence number (SN) or a PDCP sequence number (SN); a function of reordering the order and recording lost RLC PDUs; a function of transmitting a status report on lost RLC PDUs to a transmitting side; a function of requesting retransmission of lost RLC PDUs; a function of sequentially transmitting only the RLC SDUs preceding the lost RLC SDU to a higher layer when a lost RLC SDU occurs; a function of sequentially transmitting all RLC SDUs received until a given timer expires to a higher layer when there is a lost RLC SDU; a function of sequentially transmitting all RLC SDUs received so far to a higher layer when a given timer expires when there is a lost RLC SDU. In addition, the in-sequence delivery function may include the function of processing RLC PDUs in the order in which the RLC PDUs are received (in the order of arrival, regardless of the order of sequence numbers) and sending RLC PDUs to the PDCP device regardless of their order (i.e., out-of-sequence delivery). The in-sequence delivery function may include the function of receiving segments stored in the buffer or segments to be received later, reconfiguring segments in a complete RLC PDU, processing RLC PDUs, and sending RLC PDUs to the PDCP device. The NR RLC layer may not include a concatenation function. The concatenation function may be performed by the NR MAC layer or may be replaced by a multiplexing function of the NR MAC layer.

[0257] The out-of-sequence delivery function of the NR RLC device refers to a function of directly sending RLC SDUs received from a lower layer to a higher layer regardless of their order. The out-of-sequence delivery function may include a function of reassembling multiple RLC SDUs if one RLC SDU has been originally segmented into multiple RLC SDUs and received. The out-of-sequence delivery function may include a function of storing the RLCSN or PDCP SN of received RLC PDUs, reordering their order, and recording lost RLC PDUs.

[0258] NR MAC 2d-15, NR MAC 2d-30 can be connected to multiple NR RLC layer devices configured in one UE. The main functions of NR MAC may include some of the following functions.

[0259] - Mapping between logical channels and transport channels

[0260] -Multiplexing / demultiplexing of MAC SDUs

[0261] -Dispatch information report

[0262] - Error correction through HARQ

[0263] - Prioritization between logical channels of a UE

[0264] - Prioritize between UEs with dynamic scheduling

[0265] -MBMS service identification

[0266] -Transmission format selection

[0267] -filling

[0268] NR PHY layer 2d-20, NR PHY layer 2d-25 can perform operations of channel coding and modulating higher layer data, generating higher layer data into OFDM symbols, and sending OFDM symbols to a radio channel or demodulating OFDM symbols received through a radio channel, channel decoding OFDM symbols, and transmitting OFDM symbols to a higher layer.

[0269] Table 2-1 describes various pieces of information that may be included in the MAC header.

[0270] Table 2-1. MAC header variables

[0271]

[0272]

[0273] Figure 2E is a diagram illustrating a configuration of a next-generation mobile communication system according to an embodiment of the present disclosure.

[0274] refer to Figure 2E The radio access network of the next generation mobile communication system includes a new radio node B (hereinafter referred to as "NR NB") 2e-10 and a new radio core network (NR CN) 2e-05. A new radio user equipment (hereinafter referred to as "NR UE" or "terminal") 2e-15 accesses an external network through the NR NB 2e-10 and NR CN 2e-05.

[0275] exist Figure 2E In the NR NB 2e-10, the NR NB corresponds to the evolved Node B (eNB) in the existing LTE system. The NR NB 2e-10 is connected to the NR UE 2e-15 via a radio channel and can provide superior service compared to the existing Node B. Because all types of user traffic are served over shared channels, next-generation mobile communication systems require equipment for scheduling by collecting status information such as buffer status, available transmit power, and the UE's channel status. The NR NB 2e-10 is responsible for this equipment. Typically, one NR NB controls multiple cells. To implement ultra-high-speed data transmission compared to existing LTE, next-generation mobile communication systems can have bandwidths exceeding the existing maximum and can use OFDM with beamforming as the radio access technology. Furthermore, next-generation mobile communication systems employ an AMC scheme that determines the modulation scheme and channel coding rate based on the UE's channel status. The NR CN 2e-05 performs functions such as mobility support, bearer configuration, and QoS configuration. In addition to UE mobility management, the NR CN 2e-05 is responsible for various control functions and is connected to multiple eNBs. In addition, the next generation mobile communication system can also be operated in conjunction with the existing LTE system. NR CN 2e-05 is connected to MME 2e-25 through a network interface. MME 2e-25 is connected to eNB 2e-30, which is an existing eNB.

[0276] Figure 2F is a diagram schematically illustrating data transmission through packet duplication considered in an embodiment of the present disclosure and showing a process in which a UE processes a duplicated packet based on various conditions proposed in the present embodiment.

[0277] The present disclosure relates to a method for sending duplicate data through a path different from the path of the original packet (or indicated as a "leg") when the UE performs ultra-reliable low latency communication (URLLC) in the next generation mobile communication system. In one embodiment of the present disclosure, URLLC is described as an example, and the packet replication of the present disclosure is not limited to URLLC. If the duplicated data is allocated as the same MAC PDU, duplicate transmission is difficult. Therefore, if the packet is duplicated, dual connectivity (DC) or carrier aggregation (CA) can basically be used. That is, a secondary eNB (SeNB) or SCell configuration must be performed on the UE so that it can support dual connectivity or carrier aggregation. In one embodiment of the present disclosure, it is assumed that dual connectivity and carrier aggregation have been configured in the UE. The basic principle is described by a packet processing method for each type of protocol architecture in each case.

[0278] Return Reference Figure 2F, the eNB or UE receives a data packet (i.e., PDCP SDU) for URLLC from a higher layer (steps 2f-05, 2f-50) and sends the data packet to the PDCP layer. At operations 2f-10 and 2f-55, the PDCP layer determines whether to copy the data packet. If copying is necessary, the PDCP layer generates the original PDCP PDU1 and the copied PDCP PDU2 (steps 2f-15, 2f-20 and 2f-60, 2f-65) and sends them to the RLC layer (steps 2f-25, 2f-30 and 2f-70, 2f-75). The determination of packet copying is based on the packet copy activation / deactivation MAC CE (hereinafter referred to as "Du A / D MAC CE") received from the eNB. The RLC1 and RLC2 of each serving cell send the received data packet to the MAC layer of the MeNB or UE. The MAC layer maps the packet data received at operations 2f-35, 2f-80, and 2f-85 (one MAC may exist in the case of CA and two MACs may exist in the case of DC) to an appropriate logical channel group (LCG), generates a MAC PDU, generates a MAC PDU, and sends it to the physical layer of the corresponding serving cell (steps 2f-40, 2f-45 and 2f-90, 2f-95). Thereafter, the physical layer sends the MAC PDU received through the corresponding carrier aggregation or dual connectivity. In the reception process, the reverse process of the transmission process is performed without any change. That is, the physical layer receives the data packet (i.e., MAC PDU) through the corresponding serving cell and sends it to the MAC layer of the UE or corresponding eNB. Thereafter, PDCP PDU1 and PDCP PDU2 via RLC are aggregated at the PDCP of the UE or eNB. The PDCP layer checks the sequence numbers (SNs) of the received original packet and the duplicated packet, deletes one of them when the same packet is reached, and sends it to a higher layer.

[0279] In the execution operation, in this embodiment, two situations are defined, and it is defined how the UE will operate in the corresponding situations.

[0280] First, when the UE receives the Packet Duplication Deactivation MAC CE from the eNB, there is a question of how to handle the duplicate packets stored in the RLC or MAC at the corresponding moment. In this condition, the UE operates differently based on the RLC transmission mode.

[0281] 1. In the case of RLC Unacknowledged Mode (UM):

[0282] The RLC PDU / MAC SDU 2f-100 and 2f-105 that are pre-processed for duplicate transmission and that have been stored in another branch (or path) other than the preferred branch (or path) are not transmitted and are discarded.

[0283] 2. In the case of RLC Acknowledged Mode (AM):

[0284] The transmission needs to continue because the SN information in the RLC header may be necessary

[0285] a. Transmission without any changes: RLC PDU / MAC SDU or MAC PDU 2f-100, 2f-105 or 2f-110, 2f-115, 2f-120 stored in the buffer is transmitted without any changes. Including retransmission according to ACK 2f-125, 2f-130 / NACK

[0286] b. Header-only packet transmission: Only the RLC header 2f-115 and MAC header 2f-120 are transmitted in addition to the payload

[0287] c. Retransmission Discard: The eNB has deactivated packet duplication via MAC CE, meaning it no longer receives data via the corresponding path. Although the mode is RLC AM, the RLC PDUs and MAC SDUs stored in the RLC and MAC are discarded during the transmission phase. That is, when the UE receives a deactivation indication for a given path from the eNB via MAC CE deactivation, the UE discards RLC PDUs / MAC SDUs 2f-100 and 2f-105 that were pre-processed for duplicate transmission and stored in a branch (or path) other than the preferred branch (or path) without transmitting them.

[0288] Secondly, the packet copy operation is configured from the eNB in the UE through carrier aggregation (CA) or dual connectivity (DC). If the successful transmission is confirmed based on RLC ACK in one link for a given PDCP while the UE is operating, there is a problem of how to define the operation in the other links. In this problem, because the conventional Buffer Status Report (BSR) is delayed due to the priority in the Logical Channel Prioritization (LCP), the copied packet may have a later transmission time than the original data. Specifically, in the case of packet copying through DC, the original data packet and the copied data packet may be sent / received at different times because the packet copy is processed in another MAC.

[0289] 1. If the duplicate packet to be sent via another link has not yet been sent from the PDCP layer to the RLC layer, A. Stop sending

[0290] 2. If the duplicate packet to be sent through another link has been sent from the PDCP layer to the RLC layer or MAC layer and pre-processed, then

[0291] A. Transmission without any change: The RLC PDU / MAC SDU or MAC PDU 2f-100, 2f-105 or 2f-110, 2f-115, 2f-120 stored in the buffer is transmitted without any change.

[0292] B. Send only the RLC header 2f-115 and MAC header 2f-120 in addition to the header-only packet sending the payload.

[0293] Figure 2G is a diagram illustrating a structure of a packet copy activation / deactivation MAC CE according to an embodiment of the present disclosure.

[0294] First, the eNB configures which bearer or logical channel ID (LCID) can be used for packet replication through RRC configuration for the UE. Thereafter, the eNB can use MAC CE to activate / deactivate packet replication corresponding to a specific bearer or LCID of a configured bearer or LCID for the UE. In one embodiment of the present disclosure, the method of activating / deactivating packet replication through MAC CE is divided into two cases.

[0295] First, there is a method of using the Du A / D MAC CE for each UE. In this case, a UE that has received the Du A / D MAC CE activates / deactivates packet duplication for all bearers or LCIDs previously configured for packet duplication. In this case, the Du A / D MAC CE can be used as a MAC CE that includes only a header without a payload (Case 1: MAC CE per UE). That is, the Du A / D MAC CE includes only LCID 2g-15 and only reserved bits (R) 2g-40. To this end, it is necessary to map the LCID (6 bits) and the Du A / D MAC CE.

[0296] Secondly, there is a method of using Du A / D MAC CE for each resource bearer or radio bearer (RB). In this case, the UE that has received the Du A / D MAC CE only activates / deactivates the packet replication of the given RB of the bearer or LCID previously configured for packet replication. In addition, depending on whether the bearer is a DRB or an SRB, the method can operate differently. The Du A / D MAC CE for SRB can have the same structure as in Case 1: a MAC CE for each UE. That is, the Du A / D MAC CE for SRB can use a header-only MAC CE without a payload. When the UE receives a Du A / D MAC CE in which the LCID has been mapped to activation or deactivation of packet replication, it can activate or deactivate the packet replication of the SRB. In contrast, the Du A / D MAC CE for DRB needs to be specified as to which RB will be activated or deactivated by the payload. To this end, the embodiments of the present disclosure propose two structures.

[0297] Case 2-1 (MAC CE per RB): The 6-bit LCID 2g-15 is mapped to the Du A / D MAC CE, and the F field 2g-20 and L field 2g-25 may be present. In addition, the IDs 2g-30 and 2g-35 of the bearers to be activated or deactivated may be specified. The bearer ID may be 1 byte, and the size of the MAC CE may vary depending on the number of specified bearers.

[0298] - Case 2-2 (MAC CE per RB): 6-bit LCID 2g-45 is mapped to Du A / D MAC CE, and F field 2g-50 and L field 2g-55 may exist. In addition,

[0299] The DRBs that need to be activated or deactivated can be specified in a 1-byte bitmap format. In bitmap 2g-60, B0 is mapped to the DRB that belongs to the split bearer of the packet duplication configuration configured in the UE and has the lowest DRB id, and B1 is the second lowest DRB,

[0300] And a total of 8 DRBs can be designated.

[0301] Figure 2H is a diagram illustrating operations in a MAC after packet copying is activated or deactivated according to an embodiment of the present disclosure.

[0302] Figure 2HThe logical channel prioritization (LCP) operation in the MAC considered in one embodiment of the present disclosure is shown. This operation refers to LCP in LTE and is different from the existing LTE operation in that it solves problems that may occur when the existing LTE operation is performed for packet duplication without any changes.

[0303] In the MAC of the UE, when the bearer configuration with the eNB is completed, data packets are stacked at the Prioritized Bit Rate (PRB) 2h-35 set in each of the Logical Channel (LC) 2h-05, 2h-10, 2h-15, 2h-20, 2h-25 for each Transmit Time Interval (TTI) for the configured bearer. This operation is performed for each LC and is repeated during the Bucket Size Duration (BSD) 2h-30, that is, another set value. If packets are stacked during the BSD set in a given LC, the operation stops until the packets are cleared. In addition, the LCP operates based on the priority 2h-40. Describes Figure 2H An example in . For packet replication of LC 1, LC 5 is configured with the same priority at the same PBR and BSD. The parameters can be set to different values. The remaining LC 2, LC 3, and LC 4 have their own priority, PBR, and BSD. In LTE, when the eNB performs the bearer configuration of the UE, the LC and the parameters of each LC are configured together. The PBR is stacked at each TTI simultaneously with the RRC configuration. However, if such an operation is performed, although the packet replication activation has not yet started in the LC5 where packet replication has been configured, the PBR is stacked. If packet replication is activated over time by the Du A / D MAC CE, all previously stacked PBRs are used for the BSR request. Such an operation is not suitable for the purpose of introduction of activation / deactivation. Therefore, the UE may have to stack the PBR of LC5 (LC for packet replication) from the time the Du A / D MAC CE is received.

[0304] After LCP operation with such packet duplication having been applied, the UE requests a BSR from the eNB and stores data in a grant received from the eNB according to the LCP procedure. The LCP procedure may refer to a procedure in LTE and may follow the order summarized below.

[0305] 1. The data stored for each LC priority is stored sequentially (not exceeding the BSD of each LC).

[0306] 2. Store the data of all valid LCs, and if authorization still exists, store all the data of LCs with high priority and apply it to the next priority.

[0307] 3. In case of LC to which packet duplication is applied, an LCP operation is performed after receiving an activation indication of the Du A / D MAC CE.

[0308] 4. The packet copy packet and the original packet are stored in different authorizations (2h-50, 2h-55).

[0309] Figure 2I is a diagram illustrating overall operations regarding reception of a packet duplication activation / deactivation MAC CE by a UE according to an embodiment of the present disclosure.

[0310] UE 2i-01 establishes an RRC connection with eNB 2i-02 for data transmission / reception (2i-05), and receives an RRC message including bearer configuration for URLLC from eNB2i-02 (2i-10). For this operation, CA or DC can be configured. If CA is applied, bearers belonging to the SCell and configured for URLLC transmission can be additionally configured, and additional LCG cell groups and serving cells can be configured. If DC is applied, bearers configured for URLLC and serving cells can be included in the configuration of the SCG bearer. In addition, in the DRB configuration, it is indicated whether replication is applied for each separate bearer, and a preferred path can be configured for each separate bearer. That is, a path can be specified as a path that is mapped to a given logical channel id and along which a given service is sent. Alternatively, the preferred path can be used to specify the path along which the original data packet is sent, and can also be used to indicate which path is better if both paths have good quality.

[0311] Thereafter, UE 2i-01 performs uplink / downlink data transmission together with eNB 2i-02 (2i-15, 2i-25). In the case of the downlink, eNB 2i-02 can immediately perform a downlink packet copy operation on the separate bearer for which its packet copy has been configured. On the contrary, in the case of uplink packet copy, uplink packet copy is not applied in this operation because uplink packet copy is performed after activation / deactivation is indicated by Du A / D MAC CE. In the above operation, UE 2i-01 applies buffer status (BS) calculation method 1 to all DRBs used for uplink data transmission (2i-20). In BS calculation method 1, when calculating the PDCP data amount of the separate DRB, the BS is calculated by considering only the PDCP data amount of the referenced logical channel.

[0312] For a given reason, the eNB 2i-02 may indicate packet duplication of the DRB previously configured in the UE 2i-01 via the Du A / D MAC CE (2i-30). The given reason may include: the eNB 2i-02 determines the transmission link quality of the UE 2i-01 and determines that packet duplication is necessary, or the necessity of the URLLC mode may be determined based on the implementation of the eNB 2i-02 for a given service mapped to the LC. After receiving the Du A / D MAC CE, the UE 2i-01 may perform the following operations according to the conditions (2i-35).

[0313] 1. If at least one DRB replication has been newly activated due to MAC CE reception, then:

[0314] - For DRBs whose replication has been activated, change the BS calculation method from method 1 to method 2

[0315] -Regular BSR trigger

[0316] 2. If at least one new DRB copy has been deactivated due to MAC CE reception, then:

[0317] - Changed BS calculation method from Method 2 to Method 1

[0318] - In case of RLC UM DRB, discard the RLC PDU and MAC SDU pre-processed in non-preferred logical channels

[0319] - In case of RLC AM DRB, transmit RLC PDU and MAC SDU pre-processed in non-preferred logical channel without any changes, or transmit header-only packet in addition to payload

[0320] In this case, BS calculation method 1 means that when calculating the PDCP data volume, the PDCP data volume of the split DRB is considered in the BS for the preferred logical channel. BS calculation method 2 means that when calculating the PDCP data volume for both the BS for the preferred logical channel and the BS for non-preferred logical channels, the PDCP data volume of the split DRB is considered. Unlike this method, as an alternative solution, the MAC can notify the PDCP of the A / D situation, and the PDCP can appropriately notify the MAC of the PDCP data volume based on the situation.

[0321] Thereafter, at operation 2i-40, the UE performs uplink / downlink data transmission together with the eNB.

[0322] Figure 2J is a diagram illustrating an operation for a UE to perform packet duplication according to an embodiment of the present disclosure.

[0323] The UE establishes an RRC connection with the eNB for data transmission / reception (2j-05) and receives an RRC message including a bearer (DRB) configuration for URLLC from the eNB (2j-10). Thereafter, the UE applies BS calculation method 1 until it receives a MAC CE indicating packet duplication activation / deactivation and sends / receives uplink / downlink data (2j-15). When the UE receives the Du A / D MAC CE, the MAC operation in the UE is changed. That is, from the perspective of PDCP, this means that packet duplication transmission has started / stopped, but from the perspective of MAC, this means that the BS calculation method needs to be updated (2j-20).

[0324] When the received Du A / D MAC CE indicates activation (based on UE or RB, 2j-25), the UE switches to BS calculation method 2 for the corresponding DRB (or UE) (2j-30), triggers a regular BSR (2j-35), and performs data transmission / reception through the received grant (2j-40). Conversely, when the received Du A / D MAC CE indicates deactivation (based on UE or RB, 2j-25), the UE switches to BS calculation method 1 for the corresponding DRB (or UE) (2j-45) and performs operations differently based on the RLC mode (2j-50). In the case of an RLC UM DRB, the UE discards the RLC PDU and MAC SDU pre-processed in the non-preferred logical channel (2j-55). In the case of an RLC AM DRB, the UE sends the RLC PDU and MAC SDU pre-processed in the non-preferred logical channel without any change, or sends a header-only packet in addition to the payload (2j-60).

[0325] Figure 2K is a diagram illustrating a UE operation when receiving ACK from one link while performing a packet copy UE operation and confirming successful delivery of a data packet of the packet copy according to an embodiment of the present disclosure.

[0326] The UE establishes an RRC connection for data transmission / reception with the eNB (2k-05), and receives an RRC message including bearer (DRB) configuration for URLLC from the eNB (2k-10). Figure 2JThe packet copy operation described (2k-15). If the successful transmission of a given packet (to be precise, a packet sent through a different link due to the activation of the packet copy) is confirmed in one link due to the RLC ACK while the packet copy operation is being performed (2k-20), the operation of the UE is defined. At operation 2k-25, the UE identifies which link the received ACK corresponds to and continues to perform data transmission / reception by applying the BS calculation method configured for the link through which the ACK has been received (2k-30). Conversely, the UE identifies which layer the packet corresponding to the SN of the packet in which the ACK has been received has been buffered for the link through which the ACK has not yet been received (2k-45). If the corresponding packet has been buffered in the PDCP layer (2k-50), the UE discards the corresponding PDCP packet (2k-55). If the corresponding packet has been buffered in the RLC or MAC layer, the UE can send the prepared RLC PDU and MAC SDU without any change, or can send only the header other than the payload (2k-60). This operation corresponds to the case performed based on RLC AM.

[0327] Figure 2L is a diagram illustrating a configuration of a UE according to an embodiment of the present disclosure.

[0328] refer to Figure 2L , the UE includes a radio frequency (RF) processor 21-10, a baseband processor 21-20, a storage unit 21-30, and a controller 21-40.

[0329] The RF processor 21-10 performs functions for transmitting / receiving signals through a radio channel, such as frequency band conversion and amplification of the signals. That is, the RF processor 21-10 up-converts the baseband signal received from the baseband processor 21-20 into an RF band signal, transmits the RF band signal through an antenna, and down-converts the RF band signal received through the antenna into a baseband signal. For example, the RF processor 21-10 may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a DAC, and an ADC. Figure 2L In the figure, only one antenna is shown, but the UE may include multiple antennas. In addition, the RF processor 21-10 may include multiple RF chains. In addition, the RF processor 21-10 may perform beamforming. For beamforming, the RF processor 21-10 may adjust the phase and magnitude of each of the signals transmitted / received via multiple antennas or antenna elements. In addition, the RF processor may perform MIMO. When performing MIMO operation, the RF processor may receive multiple layers.

[0330] The baseband processor 21-20 performs conversion between baseband signals and bit streams based on the system's physical layer standard. For example, when transmitting data, the baseband processor 21-20 generates complex symbols by encoding and modulating the transmitted bit stream. Furthermore, when receiving data, the baseband processor 21-20 reconstructs the received bit stream from the baseband signal received from the RF processor 21-10 through modulation and demodulation. For example, if an OFDM scheme is employed, when transmitting data, the baseband processor 21-20 generates complex symbols by encoding and modulating the transmitted bit stream, maps the complex symbols to subcarriers, and then configures OFDM symbols through an IFFT operation and CP insertion. Furthermore, when receiving data, the baseband processor 21-20 segments the baseband signal received from the RF processor 21-10 into OFDM symbol units, reconstructs the signals mapped to the subcarriers through an FFT operation, and reconstructs the received bit stream through modulation and demodulation.

[0331] As described above, the baseband processor 21-20 and the RF processor 21-10 send and receive signals. Therefore, the baseband processor 21-20 and the RF processor 21-10 can be referred to as a transmitter, a receiver, a transceiver, or a communication unit. In addition, at least one of the baseband processor 21-20 and the RF processor 21-10 can include multiple communication modules to support different multiple radio access technologies. In addition, at least one of the baseband processor 21-20 and the RF processor 21-10 can include different communication modules to process signals of different frequency bands. For example, different radio access technologies can include wireless LAN (e.g., IEEE802.11) and cellular networks (e.g., LTE). In addition, different frequency bands can include ultra-high frequency (SHF) (e.g., 2.NRHz, NRhz) bands and millimeter wave (e.g., 60GHz) bands.

[0332] The storage unit 21-30 stores basic programs and applications for the operation of the UE, as well as data such as configuration information. Specifically, the storage unit 21-30 may store information related to a second access node performing wireless communication using a second radio access technology. In addition, the storage unit 21-30 provides the stored data in response to a request from the controller 21-40.

[0333] The controller 21-40 controls the overall operation of the UE. For example, the controller 21-40 transmits / receives signals via the baseband processor 21-20 and the RF processor 21-10. Furthermore, the controller 21-40 writes / reads data to / from the storage unit 21-30. To this end, the controller 21-40 may include at least one processor. For example, the controller 21-40 may include a communication processor (CP) that controls communications and an application processor (AP) that controls higher layers (such as applications).

[0334] In addition, the controller 21-40 may control receiving packet replication data radio bearer (DRB) configuration information from the eNB, receiving a MAC CE including information indicating whether packet replication has been activated from the eNB, and determining whether to activate the packet replication bearer based on the packet replication DRB configuration information and the MAC CE. The information indicating whether packet replication has been activated includes bitmap information. The bitmap information may correspond to a sequence of packet replication bearer identifiers configured by the packet replication DRB configuration information.

[0335] In addition, when the MAC CE indicates packet copy deactivation and the transmission mode of the UE is RLC AM, the controller 21-40 may control the transmission of the RLC PDU or MAC PDU that has received the packet copy deactivation indication and stored in the buffer of the bearer.

[0336] In addition, the controller 21-40 recognizes the successful transmission of the packet in the link established by CA or DC. When the MAC CE indicates packet duplication deactivation, if the duplicate packet has not been transmitted from the PDCP layer to the RLC layer, the controller 21-40 may control the discard of the duplicate packet corresponding to the packet, and if the duplicate packet has been transmitted from the PDCP layer to the RLC layer, the controller 21-40 may control the transmission of the duplicate packet.

[0337] In addition, the controller 21-40 may control the LCP operation of the LC starting the packet copy bearer after receiving the MAC CE.

[0338] Figure 2M is a diagram showing the configuration of an eNB according to an embodiment of the present disclosure.

[0339] like Figure 2M As shown, the eNB includes an RF processor 2m-10, a baseband processor 2m-20, a backhaul communication unit 2m-30, a storage unit 2m-40, and a controller 2m-50.

[0340] The RF processor 2m-10 performs functions for transmitting / receiving signals through a radio channel, such as frequency band conversion and amplification of the signals. That is, the RF processor 2m-10 up-converts the baseband signal received from the baseband processor 2m-20 into an RF band signal, transmits the RF band signal through an antenna, and down-converts the RF band signal received through the antenna into a baseband signal. For example, the RF processor 2m-10 may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a DAC, and an ADC. Figure 2MIn the figure, only one antenna is shown, but the UE may include multiple antennas. In addition, the RF processor 2m-10 may include multiple RF chains. In addition, the RF processor 2m-10 may perform beamforming. For beamforming, the RF processor 2m-10 may adjust the phase and magnitude of each of the signals transmitted / received via the multiple antennas or antenna elements. The RF processor may perform downlink MIMO operations by transmitting one or more layers.

[0341] The baseband processor 2m-20 performs conversion between baseband signals and bit streams based on the physical layer standard of the first radio access technology. For example, when transmitting data, the baseband processor 2m-20 generates complex symbols by encoding and modulating the transmitted bit stream. Furthermore, when receiving data, the baseband processor 2m-20 reconstructs the received bit stream from the baseband signal received from the RF processor 2m-10 through modulation and demodulation. For example, if an OFDM scheme is used, when transmitting data, the baseband processor 2m-20 generates complex symbols by encoding and modulating the transmitted bit stream, maps the complex symbols to subcarriers, and then configures OFDM symbols through an IFFT operation and CP insertion. Furthermore, when receiving data, the baseband processor 2m-20 segments the baseband signal received from the RF processor 2m-10 into OFDM symbol units, reconstructs the signals mapped to the subcarriers through an FFT operation, and reconstructs the received bit stream through modulation and demodulation. As described above, the baseband processor 2m-20 and the RF processor 2m-10 transmit and receive signals. Therefore, the baseband processor 2m-20 and the RF processor 2m-10 can be called a transmitter, a receiver, a transceiver, a communication unit or a wireless communication unit.

[0342] The backhaul communication unit 2m-30 provides an interface for performing communication with other nodes within the network. That is, the backhaul communication unit 2m-30 converts the bit stream sent from the master eNB to different nodes (e.g., secondary eNB or core network) into a physical signal, and converts the physical signal received from the different nodes into a bit stream.

[0343] The storage unit 2m-40 stores data such as basic programs, applications, and configuration information for the operation of the master eNB. Specifically, the storage unit 2m-40 may store information regarding bearers assigned to connected UEs and measurement results reported by connected UEs. Furthermore, the storage unit 2m-40 may store information regarding criteria for determining whether to provide or terminate dual connectivity to a UE. Furthermore, the storage unit 2m-40 provides stored data in response to a request from the controller 2m-50.

[0344] The controller 2m-50 controls the overall operation of the master eNB. For example, the controller 2m-50 transmits and receives signals through the baseband processor 2m-20 and the RF processor 2m-10, or through the backhaul communication unit 2m-30. Furthermore, the controller 2m-50 writes and reads data to and from the memory unit 2m-40. To this end, the controller 2m-50 may include at least one processor.

[0345] In addition, the controller 2m-50 may control the transmission of packet replication DRB configuration information to the UE and may transmit a MAC CE including information indicating whether packet replication has been activated to the UE. Whether to activate the packet replication bearer may be determined based on the packet replication DRB configuration information and the MAC CE. Furthermore, the information indicating whether packet replication has been activated may include bitmap information. The bitmap information may correspond to a sequence of packet replication bearer identifiers configured by the packet replication DRB configuration information.

[0346] When the MAC CE indicates packet duplication deactivation and the UE's transmission mode is RLC AM, the eNB may receive the RLC PDU or MAC PDU stored in the buffer of the bearer for which the packet duplication deactivation indication has been received. When successful transmission of a packet is recognized in a link established through CA or DC and the MAC CE indicates packet duplication deactivation, if the packet duplication has not yet been sent from the PDCP layer to the RLC layer, the duplicate packet corresponding to the packet may be discarded, and if the duplicate packet has already been sent from the PDCP layer to the RLC layer, the duplicate packet may be sent to the UE. LCP operation of the LC for the packet duplication bearer may begin after the UE receives the MAC CE.

[0347] Another embodiment of the present disclosure relates to a method and apparatus for handling packet copy transmission failure in a next generation mobile communication system.

[0348] Figure 3A is a diagram illustrating a configuration of a next-generation mobile communication system according to an embodiment of the present disclosure.

[0349] refer to Figure 3A The radio access network of the next generation mobile communication system includes a new radio node B (hereinafter referred to as "NR NB") 3a-10 and a new radio core network (NR CN) 3a-05. A new radio user equipment (hereinafter referred to as "NR UE" or "NR terminal") 3a-15 accesses an external network through the NR NB 3a-10 and the NR CN 3a-05.

[0350] exist Figure 3AIn the NR NB 3a-10, the NR NB 3a-10 corresponds to the eNB in the existing LTE system. The NR NB 3a-10 is connected to the NR UE 3a-15 via a radio channel and can provide superior service compared to the existing Node B. Because all types of user traffic are served over shared channels, next-generation mobile communication systems require equipment for performing scheduling by collecting status information such as buffer status, available transmit power, and the UE's channel status. The NR NB 3a-10 is responsible for this equipment. Typically, one NR NB controls multiple cells. To implement ultra-high-speed data transmission compared to existing LTE, next-generation mobile communication systems can have bandwidths exceeding the existing maximum and can use OFDM with beamforming technology as a radio access technology. In addition, next-generation mobile communication systems adopt an AMC scheme that determines the modulation scheme and channel coding rate based on the UE's channel status. The NR CN 3a-05 performs functions such as mobility support, bearer configuration, and QoS configuration. In addition to UE mobility management, the NR CN 3a-05 is responsible for various control functions and is connected to multiple eNBs. In addition, the next generation mobile communication system can also be operated in conjunction with the existing LTE system. NR CN 3a-05 is connected to MME 3a-25 through a network interface. MME 3a-25 is connected to eNB 3a-30, which is an existing eNB.

[0351] Figure 3B is a diagram illustrating a protocol structure of a transmission phase and a reception phase for high-reliability low-latency communication for a given traffic type / radio bearer according to an embodiment of the present disclosure. Figure 3BThis corresponds to a method in which the PDCP layer 3b-01 generates duplicate packets with the same SN as the same packet for a given traffic type / radio bearer and sends the duplicate packets to independent RLC layers 3b-03 and 3b-05, but sends the duplicate packets via a shared MAC layer 3b-07. In this case, the PDCP layer manages the SNs in the RLC layer separately by sending the same packets to different RLC layers. The MAC layer 3b-07 sends packets received from the respective RLC layers to the same physical layer or different physical layers 3b-11 and 3b-13. The physical layers 3b-15 and 3b-17, having received the packets, send the packets to the corresponding MAC layer 3b-19. The packets are then sent to the corresponding RLC layers 3b-23 and 3b-25 and ultimately to the PDCP layer 3b-27. If all packets with duplicate SNs are successfully sent via different paths and reach the PDCP layer 3b-27, the duplicate packets are discarded and only one packet is sent to higher layers on the receiving side. In addition, it is assumed that the RLC layer is an entity operating according to an unacknowledged mode (UM) method without retransmission of automatic repeat request (ARQ) through low-latency communication. In addition, different physical layers can use different frequencies or spatially different resources of the same frequency or different antennas.

[0352] Figure 3C is a diagram for illustrating a radio link monitoring (RLM) operation in LTE technology according to an embodiment of the present disclosure.

[0353] The physical layer (PHY) of the UE measures the downlink signal quality of the cell-specific reference (CRS) signal from the serving cell (3c-05). The physical layer determines whether the signal quality is lower than a given threshold Qout (3c-10). The threshold is a signal quality value corresponding to a given BLER measured in the PDCCH. If the signal quality is lower than a given threshold Qout, the physical layer sends an "out of synchronization" indicator to a higher layer. In LTE technology, this operation is called RLM. When a given number or more indicators are sent to a higher layer, the higher layer drives a given timer. When the timer expires, the higher layer declares a radio link failure (RLF) (3c-15).

[0354] Figure 3D is a diagram for illustrating an RLF operation in an LTE technology according to an embodiment of the present disclosure.

[0355] As described above, RLF can be declared based on the result from RLM. The physical layer of the UE determines whether the downlink signal quality is lower than a given threshold Qout based on the CRS of the serving cell in a given period or each Qout evaluation period. If the signal quality is lower than the given threshold Qout, the physical layer sends an "out of synchronization" indicator to the higher layer. After the minimum indicator is sent to the higher layer (3d-05), when the minimum indicator is sent to the higher layer a given number N310, a given timer T310 is driven (3d-10). The physical layer determines whether the downlink signal quality is higher than a given threshold Qin based on the CRS of the serving cell. If the signal quality is higher than the given threshold Qin, the physical layer sends an "in synchronization" indicator to the higher layer. When the indicator is sent to the higher layer a given number, the driving timer T310 stops. If timer T310 does not stop and expires, the higher layer declares RLF (3d-15). After declaring RLF, the UE drives another timer T311. The UE finds a new suitable cell. If the UE does not find a suitable cell until timer T311 expires, the UE switches to idle mode (3d-25). If the UE finds a new suitable cell before the timer expires, it drives timer T301 and performs a re-establishment process on the new cell (3d-20). If the re-establishment is not successfully completed until timer T301 expires, the UE switches to idle mode (3d-30). When the re-establishment is successful, the UE continues to maintain the connected mode of the cell. RLF can be declared by the RLM operation, or can be declared under another condition. RLF may be declared when random access fails (3d-35). In addition, although the maximum number of retransmissions is reached in the RLC layer, if the packet is not successfully sent, RLF is declared (3d-40).

[0356] The embodiments of the present disclosure propose a solution for declaring RLF based on the RLC problem in the aforementioned packet duplication and transmission technology.

[0357] In carrier aggregation technology, a single RLC layer exists within the UE. Therefore, the aforementioned operations apply. In contrast, in dual connectivity technology, two RLC layers exist within the UE. One RLC layer processes packets related to the MeNB, while the other RLC layer processes packets related to the SeNB. The MCG RLC corresponding to the MeNB determines whether the RLF condition is met and, if so, declares the RLF. The SCG RLC corresponding to the SeNB determines whether the RLF condition is met and, if so, resets the SCG Failure Information procedure without declaring the RLF. This procedure reports to the MeNB that a problem has occurred in the PSCell.

[0358] The packet duplication transmission technology is based on the carrier aggregation technology, but differs from the carrier aggregation technology in that two RLC layers are present. Therefore, a new RLF declaration rule may be necessary.

[0359] Figure 3E is a diagram illustrating a first scheme of processing an RLC problem when a packet is copied and transmitted in a next generation mobile communication system according to an embodiment of the present disclosure.

[0360] In the first scenario, when a maximum retransmission occurs in one of the two RLC layers, the UE declares an RLF and performs an RRC connection reestablishment procedure on a newly discovered suitable cell. The PDCP layer 3e-05 sends duplicate copies of the same packet to both RLC layers 3e-10 and 3e-15. The RLC layers 3e-10 and 3e-15 process the same packet and send it to a single MAC layer 3e-20. In this scenario, when a maximum retransmission occurs in one of the two RLC layers (3e-10), the UE declares an RLF. When an RLF is declared, the other RLC layer 3e-15, which did not perform a maximum retransmission, stops processing the packet.

[0361] In the first scenario, performing RRC connection re-establishment may be an over-reaction because another RLC layer is still able to successfully send / receive packets.

[0362] Figure 3F is a diagram illustrating a second scheme of processing an RLC problem when a packet is copied and transmitted in a next generation mobile communication system according to an embodiment of the present disclosure.

[0363] In the second approach, when maximum retransmissions occur in both RLC layers, the UE declares an RLF and performs an RRC connection reestablishment procedure on a newly discovered suitable cell. However, when maximum retransmissions occur in only one RLC layer, the UE does not declare an RLF and reports the problem to higher layers. Furthermore, when maximum retransmissions occur, RLC layer operations can be divided into two options.

[0364] Option 1) The RLC layer in which maximum retransmission has occurred reports to the higher layer that maximum retransmission has occurred, suspends packet processing and waits for new configuration from the higher layer.

[0365] Option 2) The RLC layer in which maximum retransmission has occurred reports to a higher layer that maximum retransmission has occurred and continues to perform packet processing. A detailed method for continuing to perform packet processing is described below.

[0366] Method 1: Delete the packet that has undergone the maximum retransmission, reset the number of retransmissions for the complete count, restart the number of retransmissions, and perform the next packet transmission.

[0367] Method 2: Reset the full count of retransmissions, restart the retransmission number, and continue to perform retransmissions of the processed packet. When the restarted retransmission number reaches the maximum retransmission number, the RLC layer reports it to the higher layer again. Retransmission can continue until a given number of reports occur, until an indication is received from a higher layer or other RLC layer, or until the packet duplication configuration is released. The given number can be preset or preset by dedicated RRC signaling from the network. The network can configure it by dividing the maximum retransmission number information indicating that an RLC problem has occurred into an object for declaring RLF and an object for reporting the RLC problem to the higher layer. This configuration is sent to the UE by dedicated RRC signaling.

[0368] The PDCP layer 3f-05 sends a copy of the same packet to two RLC layers 3f-10 and 3f-15. Each of the RLC layers 3f-10 and 3f-15 processes the same packet and sends it to a single MAC layer 3f-20. At this point, if a maximum retransmission occurs in one of the two RLC layers, for example, the RLC layer 3f-10, where the maximum retransmission has occurred, performs one of two options. For example, the RLC layer 3f-15, where the maximum retransmission has not occurred, continues packet processing.

[0369] Figure 3G is a diagram illustrating an operation of a UE processing an RLC problem when a packet is copied and transmitted in a next generation mobile communication system according to an embodiment of the present disclosure.

[0370] At operation 3g-05, the UE applies the configuration information for packet copy transmission received from the eNB. At operation 3g-10, the UE receives a MAC CE for activating packet copy transmission from the eNB, and then triggers packet copy transmission. At operation 3g-15, the UE identifies that maximum retransmission has occurred in the RLC layer. At operation 3g-20, the UE determines whether maximum retransmission has occurred in all RLC layers or in only one RLC layer. If maximum retransmission has occurred in all RLC layers, the UE declares RLF at operation 3g-25 and initializes an RRC connection reestablishment operation at operation 3g-30. If maximum retransmission has occurred in only one RLC, the UE reports to a higher layer that a problem has occurred at operation 3g-35. The higher layer means the RRC layer. At operation 3g-40, the UE performs one of the following operations.

[0371] Option 1) The RLC layer where maximum retransmission has occurred suspends packet processing and waits for new configuration from higher layers.

[0372] Option 2) The RLC layer where maximum retransmission has occurred continues to perform packet processing.

[0373] For example, the UE may perform the following operations based on the result of the determination at operation 3g-20. If the condition of operation 3g-20 is met only in the SCG RLC layer corresponding to the SeNB, the UE does not declare an RLF, but may report the occurrence of the problem to higher layers at operation 3g-35. If it is determined at operation 3g-20 that the maximum number of retransmissions has been reached in all RLCs of the UE, the condition of the maximum number of retransmissions is met even in the RLC of the MCG corresponding to the MeNB. The UE may declare an RLF at operation 3g-25.

[0374] Figure 3H is a diagram illustrating a configuration of a UE according to an embodiment of the present disclosure.

[0375] refer to Figure 3H , the UE includes a radio frequency (RF) processor 3h-10, a baseband processor 3h-20, a storage unit 3h-30 and a controller 3h-40.

[0376] The RF processor 3h-10 performs functions for transmitting / receiving signals through a radio channel, such as frequency band conversion and amplification of the signals. That is, the RF processor 3h-10 up-converts the baseband signal received from the baseband processor 3h-20 into an RF band signal, transmits the RF band signal through an antenna, and down-converts the RF band signal received through the antenna into a baseband signal. For example, the RF processor 3h-10 may include a transmitting filter, a receiving filter, an amplifier, a mixer, an oscillator, a DAC, and an ADC. Figure 3H In the figure, only one antenna is shown, but the eNB may include multiple antennas. In addition, the RF processor 3h-10 may include multiple RF chains. In addition, the RF processor 3h-10 may perform beamforming. For beamforming, the RF processor 3h-10 may adjust the phase and magnitude of each of the signals transmitted / received through the multiple antennas or antenna elements. In addition, the RF processor may perform MIMO and may receive multiple layers when performing MIMO operations.

[0377] The baseband processor 3h-20 performs the conversion function between the baseband signal and the bit stream based on the physical layer standard of the system. For example, when sending data, the baseband processor 3h-20 generates complex symbols by encoding and modulating the sending bit stream. In addition, when receiving data, the baseband processor 3h-20 reconstructs the received bit stream from the baseband signal by modulation and demodulation, and the baseband signal is received from the RF processor 3h-10. For example, if the OFDM scheme is applied, when sending data, the baseband processor 3h-20 generates complex symbols by encoding and modulating the sending bit stream, maps the complex symbols to subcarriers, and then configures OFDM symbols through IFFT operation and CP insertion. In addition, when receiving data, the baseband processor 3h-20 segments the baseband signal received from the RF processor 3h-10 in OFDM symbol units, reconstructs the signal mapped to the subcarriers through FFT operation, and then reconstructs the received bit stream through modulation and demodulation.

[0378] As described above, the baseband processor 3h-20 and the RF processor 3h-10 send and receive signals. Therefore, the baseband processor 3h-20 and the RF processor 3h-10 can be referred to as a transmitter, a receiver, a transceiver, a communication unit or a wireless communication unit. In addition, at least one of the baseband processor 3h-20 and the RF processor 3h-10 may include a plurality of communication modules to support different multiple radio access technologies. In addition, at least one of the baseband processor 3h-20 and the RF processor 3h-10 may include different communication modules to process signals of different frequency bands. For example, different radio access technologies may include wireless LAN (e.g., IEEE802.11) and cellular networks (e.g., LTE). In addition, different frequency bands may include ultra-high frequency (SHF) (e.g., 2.NRHz, NRhz) bands and millimeter wave (e.g., 60GHz) bands.

[0379] The storage unit 3h-30 stores basic programs and applications for the operation of the UE, as well as data such as configuration information. Specifically, the storage unit 3h-30 may store information related to a second access node performing wireless communication using a second radio access technology. In addition, the storage unit 3h-30 provides the stored data in response to a request from the controller 3h-40.

[0380] The controller 3h-40 controls the overall operation of the UE. For example, the controller 3h-40 sends / receives signals through the baseband processor 3h-20 and the RF processor 3h-10. In addition, the controller 3h-40 writes / reads data to / from the storage unit 3h-30. To this end, the controller 3h-40 may include at least one processor. For example, the controller 3h-40 may include a communication processor (CP) that performs control of communication and an application processor (AP) that controls higher layers (such as applications).

[0381] Figure 3I Is a diagram showing the configuration of an eNB according to an embodiment of the present disclosure.

[0382] like Figure 3I As shown, the eNB includes an RF processor 3i-10, a baseband processor 3i-20, a backhaul communication unit 3i-30, a storage unit 3i-40, and a controller 3i-50.

[0383] The RF processor 3i-10 performs functions for transmitting / receiving signals through a radio channel, such as frequency band conversion and amplification of the signals. That is, the RF processor 3i-10 up-converts the baseband signal received from the baseband processor 3i-20 into an RF band signal, transmits the RF band signal through an antenna, and down-converts the RF band signal received through the antenna into a baseband signal. For example, the RF processor 3i-10 may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a DAC, and an ADC. Figure 3I In the figure, only one antenna is shown, but the first access node may include multiple antennas. In addition, the RF processor 3i-10 may include multiple RF chains. In addition, the RF processor 3i-10 may perform beamforming. For beamforming, the RF processor 3i-10 may adjust the phase and magnitude of each of the signals transmitted / received via the multiple antennas or antenna elements. The RF processor may perform downlink MIMO operations by transmitting one or more layers.

[0384] The baseband processor 3i-20 performs conversion between baseband signals and bit streams based on the physical layer standard of the first radio access technology. For example, when transmitting data, the baseband processor 3i-20 generates complex symbols by encoding and modulating the transmitted bit stream. Furthermore, when receiving data, the baseband processor 3i-20 reconstructs the received bit stream from the baseband signal received from the RF processor 3i-10 through modulation and demodulation. For example, if an OFDM scheme is used, when transmitting data, the baseband processor 3i-20 generates complex symbols by encoding and modulating the transmitted bit stream, maps the complex symbols to subcarriers, and then configures OFDM symbols through an IFFT operation and CP insertion. Furthermore, when receiving data, the baseband processor 3i-20 segments the baseband signal received from the RF processor 3i-10 into OFDM symbol units, reconstructs the signals mapped to the subcarriers through an FFT operation, and then reconstructs the received bit stream through modulation and demodulation. As described above, the baseband processor 3i-20 and the RF processor 3i-10 transmit and receive signals. Therefore, the baseband processor 3i-20 and the RF processor 3i-10 can be referred to as a transmitter, a receiver, a transceiver, a communication unit or a wireless communication unit.

[0385] The backhaul communication unit 3i-30 provides an interface for performing communication with other nodes within the network. That is, the backhaul communication unit 3i-30 converts the bit stream sent from the master eNB to different nodes (e.g., secondary eNB or core network) into a physical signal, and converts the physical signal received from different nodes into a bit stream.

[0386] The storage unit 3i-40 stores data such as basic programs, applications, and configuration information for the operation of the master eNB. Specifically, the storage unit 3i-40 may store information regarding bearers allocated to connected UEs and measurement results reported by connected UEs. Furthermore, the storage unit 3i-40 may store information regarding criteria for determining whether to provide or terminate dual connectivity to a UE. Furthermore, the storage unit 3i-40 provides stored data in response to a request from the controller 3i-50.

[0387] The controller 3i-50 controls the overall operation of the master eNB. For example, the controller 3i-50 transmits and receives signals via the baseband processor 3i-20 and RF processor 3i-10, or via the backhaul communication unit 3i-30. Furthermore, the controller 3i-50 writes and reads data from the memory unit 3i-40. Specifically, with respect to the present disclosure, the controller 3i-50 writes and reads a COUNT value to and from the memory unit 3i-40. To this end, the controller 3i-50 may include at least one processor.

[0388] According to an embodiment of the present disclosure, a method for a UE and an eNB to perform a count check operation in a next-generation mobile communication system specifically defines the UE operation. Therefore, the count check operation for each of Signaling Radio Bearer (SRB) 1 and SRB 3 and the corresponding SRB operation for Packet Data Convergence Protocol (PDCP) reordering are accurately performed, enabling accurate PDCP count operations.

[0389] In addition, according to an embodiment of the present disclosure, specifically, when a packet copy activation / deactivation MAC CE is received, operations of a UE and an eNB through packet copying can be clarified by defining a method of transmitting data of a newly introduced packet copying in a next generation mobile communication system.

[0390] Furthermore, according to the embodiments of the present disclosure, a method and apparatus for processing packet copy transmission failure in a next generation mobile communication system can be provided.

[0391] In addition, the various embodiments of the present disclosure disclosed in the specification and the drawings are only specific examples in order to easily describe the content of the present disclosure and help understand the present disclosure, and are not intended to limit the scope of the present disclosure. Therefore, in addition to the disclosed embodiments, all modifications or modifications derived based on the technical spirit of the present disclosure should be interpreted as being included in the scope of the present disclosure.

[0392] Although the present disclosure has been described with various embodiments, various changes and modifications may occur to those skilled in the art. The present disclosure is intended to encompass such changes and modifications as fall within the scope of the appended claims.

Claims

1. A method performed by a terminal, the method comprising: receiving a counter check request message including a data radio bearer (DRB) count most significant bit (MSB) information list from a base station; In a case where a first DRB is included in the DRB count MSB information list, identifying whether a downlink most significant bit (MSB) value of the terminal for the first DRB is different from a downlink MSB value of the base station for the first DRB indicated by the DRB count MSB information list, wherein the downlink MSB value of the terminal for the first DRB is determined based on a highest count value of a Packet Data Convergence Protocol (PDCP) Service Data Unit (SDU) that has been received; and sending a counter check response message to the base station, wherein, in a case where the downlink MSB value of the terminal for the first DRB is different from the downlink MSB value of the base station for the first DRB, the counter check response message includes first DRB counting information associated with the first DRB, wherein the first DRB counting information is a full count value of the first PDCP SDU corresponding to the downlink MSB value of the terminal for the first DRB, and In which, when the second DRB is not included in the DRB count MSB information list, the counter check response message includes the second DRB count information of the second DRB of the cell group of the terminal, wherein the second DRB count information is the full count value of the second PDCP SDU corresponding to the downlink MSB value of the terminal for the second DRB.

2. The method according to claim 1, wherein The highest count value of the PDCP SDU corresponds to the count value of the next PDCP SDU to be received minus one.

3. The method according to claim 1, in, The counter check request message is received via signaling radio bearer SRB1.

4. The method according to claim 3, in, In the case where the counter check request message is associated with a primary cell group MCG, the counter check response message includes DRB count information associated with the MCG bearer, but does not include DRB count information associated with the secondary cell group SCG bearer, and In the case where the counter check request message is associated with the SCG, the counter check response message includes DRB counting information associated with the SCG bearer, but does not include DRB counting information associated with the MCG bearer.

5. The method according to claim 1, in, In a case where the downlink MSB value of the terminal is identical to the downlink MSB value of the base station, the counter check response message does not include first DRB count information associated with the first DRB.

6. A method performed by a base station, the method comprising: Sending a counter check request message including a data radio bearer (DRB) count most significant bit (MSB) information list to the terminal; as well as receiving a counter check response message from the terminal, wherein, in a case where the first DRB is included in the DRB count MSB information list, whether the downlink most significant bit MSB value of the terminal for the first DRB is different from the downlink MSB value of the base station for the first DRB indicated by the DRB count MSB information list is identified by the terminal, The downlink MSB value of the terminal for the first DRB is determined based on the highest count value of the PDCP SDU in the received Packet Data Convergence Protocol PDCP Service Data Unit SDU, wherein, in a case where the downlink MSB value of the terminal for the first DRB is different from the downlink MSB value of the base station for the first DRB, the counter check response message includes first DRB counting information associated with the first DRB, wherein the first DRB counting information is a full count value of the first PDCP SDU corresponding to the downlink MSB value of the terminal for the first DRB, and In which, when the second DRB is not included in the DRB count MSB information list, the counter check response message includes the second DRB count information of the second DRB of the cell group of the terminal, wherein the second DRB count information is the full count value of the second PDCP SDU corresponding to the downlink MSB value of the terminal for the second DRB.

7. The method according to claim 6, in, The highest count value of the PDCP SDU corresponds to the count value of the next PDCP SDU to be received minus one.

8. The method according to claim 6, in, The counter check request message is sent via signaling radio bearer SRB1.

9. The method according to claim 8, in, In the case where the counter check request message is associated with a primary cell group MCG, the counter check response message includes DRB count information associated with the MCG bearer, but does not include DRB count information associated with the secondary cell group SCG bearer, and In the case where the counter check request message is associated with the SCG, the counter check response message includes DRB counting information associated with the SCG bearer, but does not include DRB counting information associated with the MCG bearer.

10. The method according to claim 6, in, In a case where the downlink MSB value of the terminal is identical to the downlink MSB value of the base station, the counter check response message does not include first DRB count information associated with the first DRB.

11. A terminal comprising: transceiver; and The controller is configured as: receiving a counter check request message including a data radio bearer (DRB) count most significant bit (MSB) information list from a base station via the transceiver, identifying, in a case where a first DRB is included in the DRB count MSB information list, whether a downlink most significant bit (MSB) value of the terminal for the first DRB is different from a downlink MSB value of the base station for the first DRB indicated by the DRB count MSB information list, wherein the downlink MSB value of the terminal for the first DRB is determined based on a highest count value of a Packet Data Convergence Protocol (PDCP) Service Data Unit (SDU) that has been received, and sending a counter check response message to the base station via the transceiver, wherein, in a case where the downlink MSB value of the terminal for the first DRB is different from the downlink MSB value of the base station for the first DRB, the counter check response message includes first DRB counting information associated with the first DRB, wherein the first DRB counting information is a full count value of the first PDCP SDU corresponding to the downlink MSB value of the terminal for the first DRB, and In which, when the second DRB is not included in the DRB count MSB information list, the counter check response message includes the second DRB count information of the second DRB of the cell group of the terminal, wherein the second DRB count information is the full count value of the second PDCP SDU corresponding to the downlink MSB value of the terminal for the second DRB.

12. The terminal according to claim 11, in, The highest count value of the PDCP SDU corresponds to the count value of the next PDCP SDU to be received minus one.

13. The terminal according to claim 11, in, The controller is further configured to identify whether the counter check request message is received over a signaling radio bearer SRB1.

14. The terminal according to claim 13, in, In the case where the counter check request message is associated with a primary cell group MCG, the counter check response message includes DRB count information associated with the MCG bearer, but does not include DRB count information associated with the secondary cell group SCG bearer, and In the case where the counter check request message is associated with the SCG, the counter check response message includes DRB counting information associated with the SCG bearer, but does not include DRB counting information associated with the MCG bearer.

15. The terminal according to claim 11, in, In a case where the downlink MSB value of the terminal is identical to the downlink MSB value of the base station, the counter check response message does not include first DRB count information associated with the first DRB.

16. A base station, comprising: transceiver; and The controller is configured as: sending a counter check request message including a data radio bearer (DRB) count most significant bit (MSB) information list to the terminal via the transceiver, and receiving a counter check response message from the terminal via the transceiver, wherein, in a case where the first DRB is included in the DRB count MSB information list, whether the downlink most significant bit MSB value of the terminal for the first DRB is different from the downlink MSB value of the base station for the first DRB indicated by the DRB count MSB information list is identified by the terminal, The downlink MSB value of the terminal for the first DRB is determined based on the highest count value of the PDCP SDU in the received Packet Data Convergence Protocol PDCP Service Data Unit SDU, wherein, in a case where the downlink MSB value of the terminal for the first DRB is different from the downlink MSB value of the base station for the first DRB, the counter check response message includes first DRB counting information associated with the first DRB, wherein the first DRB counting information is a full count value of the first PDCP SDU corresponding to the downlink MSB value of the terminal for the first DRB, and In which, when the second DRB is not included in the DRB count MSB information list, the counter check response message includes the second DRB count information of the second DRB of the cell group of the terminal, wherein the second DRB count information is the full count value of the second PDCP SDU corresponding to the downlink MSB value of the terminal for the second DRB.

17. The base station according to claim 16, in, The highest count value of the PDCP SDU corresponds to the count value of the next PDCP SDU to be received minus one.

18. The base station according to claim 16, in, The counter check request message is sent via signaling radio bearer SRB1.

19. The base station according to claim 18, in, In the case where the counter check request message is associated with a primary cell group MCG, the counter check response message includes DRB count information associated with the MCG bearer, but does not include DRB count information associated with the secondary cell group SCG bearer, and In the case where the counter check request message is associated with the SCG, the counter check response message includes DRB counting information associated with the SCG bearer, but does not include DRB counting information associated with the MCG bearer.

20. The base station according to claim 16, in, In a case where the downlink MSB value of the terminal is identical to the downlink MSB value of the base station, the counter check response message does not include first DRB count information associated with the first DRB.

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