Method and apparatus for splitting downlink radio resource control message in mobile communication system

Abstract

The disclosure relates to a communication technology for converging IoT technology and a 5G communication system supporting a higher data transmission rate than a 4G system, and a system thereof. The disclosure can be applied to intelligent services (e.g., smart home, smart building, smart city, smart car or connected car, health care, digital education, retail business, security and safety-related services, etc.) based on 5G communication technology and IoT-related technology. According to an embodiment of the disclosure, a method of a terminal in a communication system can include receiving at least one split radio resource control (RRC) message from a base station, the split RRC message including a part of an RRC message that is greater than a preset size, storing the received at least one split RRC message, identifying that a radio link failure (RLF) with respect to the base station has occurred, and discarding the stored split RRC message when the radio link failure has occurred.

Description

Technical Field

[0001] This invention relates to a mobile communication system, specifically, to a method for a base station to segment and deliver downlink RRCReconfiguration messages and terminal operations. Background Technology

[0002] To meet the increasing demand for wireless data services following the commercialization of 4G communication systems, efforts are underway to develop enhanced 5G or pre-5G communication systems. For this reason, 5G or pre-5G communication systems are referred to as post-4G or post-LTE systems. To achieve high data transmission rates, the implementation of 5G communication systems in millimeter-wave segmentation (e.g., 60 GHz) is considered. To reduce path loss and increase transmission distance in millimeter-wave segmentation, beamforming, massive MIMO, full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and massive MIMO technologies are discussed in 5G communication systems. Furthermore, to improve the network of the system, technologies such as improved small cells, advanced small cells, cloud radio access networks (cloud RAN), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, mobile networks, cooperative communication, cooperative multipoint (CoMP), and receive interference cancellation are being developed in 5G communication systems. In addition, hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC) are being developed as advanced coding and modulation (ACM) schemes in 5G systems, as well as filter bank multicarrier (FBMC), non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA) as advanced access technologies.

[0003] Simultaneously, the Internet has evolved from a human-centric network connecting information generated and consumed by humans to the Internet of Things (IoT), through which information is exchanged and processed between distributed components such as things. An emerging technology is the Internet of Everything (IoE), which combines big data processing technologies connected to cloud servers with IoT technologies. To realize IoT, technological elements such as sensing technologies, wired / wireless communication and network infrastructure, service interface technologies, and security technologies are required. Therefore, technologies for connecting things, such as sensor networks, machine-to-machine (M2M), and machine-type communication (MTC), have recently been researched. In the IoT environment, intelligent Internet technology (IT) services can be provided, where new value is created for human life by collecting and analyzing data generated from connected things. Through the convergence and combination of existing information technology (IT) and various industries, IoT can be applied to fields such as smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, healthcare, smart appliances, and advanced medical services.

[0004] Therefore, various attempts are underway to apply 5G communication systems to IoT. For example, technologies such as sensor networks, machine-to-machine (M2M), and machine-type communication (MTC) are being implemented using schemes such as beamforming, MIMO, and array antennas (i.e., 5G communication technologies). Cloud radio access networks (cloud RAN), as an application of the aforementioned big data processing technologies, can be seen as an example of the convergence between 5G and IoT technologies. Summary of the Invention

[0005] This paper introduces a process in an NR system where, when the UE capability information exceeds the maximum size of a PDCP SDU, the UE receives a request for its capabilities from the base station and reports its capabilities, along with a method for segmenting and delivering UE capability information messages. Similarly, even in the case of downlink RRC messages, situations may arise where the configuration information exceeds the maximum size of the PDCP SDU. Currently, methods for segmenting and delivering downlink RRC messages are not supported. Furthermore, when segmentation of downlink RRC messages is permitted, UE operations need to be defined.

[0006] [Solution]

[0007] A method for a user equipment in a communication system according to embodiments of the present disclosure may include: receiving at least one segmented radio resource control (RRC) message from a base station, the segmented RRC message including a portion of an RRC message larger than a preset size; storing the received at least one segmented RRC message; identifying whether a radio link failure (RLF) has occurred with respect to the base station; and discarding the stored segmented RRC message based on the occurrence of the RLF.

[0008] According to an embodiment, the RLF may be an RLF associated with the primary cell group (MCG).

[0009] According to an embodiment, the RRC message can be an RRCReconfiguration message or an RRCResume message.

[0010] According to an embodiment, the occurrence of RLF can be identified when no last segmented RRC message related to the RRC message is received from the base station.

[0011] Furthermore, a method for a base station in a communication system according to embodiments of this disclosure may include: generating a Radio Resource Control (RRC) message to be sent to a User Equipment (UE); generating at least one segmented RRC message including a portion of the RRC message based on the fact that the size of the RRC message is greater than a preset size; and sending the at least one segmented RRC message to the UE. The at least one segmented RRC message sent to the UE may be discarded by the UE based on a Radio Link Failure (RLF) occurring at the base station.

[0012] Furthermore, the user equipment (UE) of the communication system according to embodiments of this disclosure may include a transceiver unit and a controller, the controller being configured to receive at least one segmented radio resource control (RRC) message from a base station, the segmented RRC message including a portion of an RRC message larger than a preset size, store the received at least one segmented RRC message, identify a radio link failure (RLF) that has occurred with respect to the base station, and discard the stored segmented RRC message based on the occurrence of the RLF.

[0013] Furthermore, the base station of the communication system according to embodiments of this disclosure may include a transceiver unit and a controller. The controller is configured to generate a Radio Resource Control (RRC) message to be sent to a User Equipment (UE), generate at least one segmented RRC message including a portion of the RRC message based on the RRC message size being greater than a preset size, and enable the at least one segmented RRC message to be sent to the UE. The at least one segmented RRC message sent to the UE may be discarded by the UE based on a Radio Link Failure (RLF) occurring at the base station.

[0014] [Beneficial Effects]

[0015] According to this disclosure, when downlink (DL) segmented RRC messages are introduced into an NR system, downlink RRC messages larger than the maximum size of a PDCP SDU can also be generated and delivered. Because UE operations for DL ​​segmented RRC messages are defined, the base station can deliver large amounts of configuration information to the UE without problems, even with small delays. Attached Figure Description

[0016] Figure 1 This is a diagram illustrating the configuration of an LTE system according to an embodiment of the present disclosure.

[0017] Figure 2 This is a diagram illustrating the radio protocol architecture in an LTE system according to an embodiment of the present disclosure.

[0018] Figure 3 This is a diagram illustrating the configuration of a next-generation mobile communication system according to an embodiment of the present disclosure.

[0019] Figure 4 This is a diagram illustrating the radio protocol architecture of a next-generation mobile communication system according to an embodiment of the present disclosure.

[0020] Figure 5 This is a diagram illustrating a method for applying segmentation to RRC control messages via the downlink in an NR system according to an embodiment of the present disclosure.

[0021] Figure 6This is a diagram illustrating a method for applying segmentation to downlink RRC messages in an NR system according to an embodiment of the present disclosure.

[0022] Figure 7 This is a diagram illustrating the operation of the UE and the base station in the case of applying segmentation to downlink RRC messages according to an embodiment of the present disclosure.

[0023] Figure 8 This is a diagram illustrating UE operation according to a first embodiment of the present disclosure, wherein segmented RRC control messages are generated and delivered via a specific SRB.

[0024] Figure 9 This is a diagram illustrating UE operation according to a second embodiment of the present disclosure when a segmented RRC control message is generated and delivered via a specific SRB and an RLF occurs.

[0025] Figure 10 This is a diagram illustrating UE operation according to a third embodiment of the present disclosure when a segmented RRC control message is generated and delivered via a specific SRB and indicates an RRC state transition.

[0026] Figure 11 This is a diagram illustrating UE operation according to a fourth embodiment of the present disclosure when a segmented RRC control message is generated and delivered via a specific SRB and indicates mobility, i.e., a handover or PSCell change is indicated via the RRC message.

[0027] Figure 12 This is a diagram illustrating base station operation according to an embodiment of the present disclosure.

[0028] Figure 13 This is a diagram illustrating the configuration of a UE according to an embodiment of the present disclosure.

[0029] Figure 14 This is a diagram illustrating the configuration of a base station according to an embodiment of the present disclosure. Detailed Implementation

[0030] The operating principles of this disclosure will be described in detail below with reference to the accompanying drawings. In the following description of this disclosure, detailed descriptions of relevant known functions or configurations will be omitted if it is deemed unnecessary to obscure the subject matter of this disclosure. For the same reason, some components are shown enlarged, omitted, or schematically in the drawings. Furthermore, the dimensions of each component do not accurately reflect its actual size. Additionally, the terms described below are defined by consideration of the functions in this disclosure and may vary depending on the intent or practice of the user or operator. Therefore, each term should be defined based on the content throughout the specification. In the following description, for ease of description, examples are given of terms for identifying connected nodes, for representing network entities, for representing messages, for representing interfaces between network entities, for representing various types of identification information, etc. Therefore, this disclosure is not limited to the terms described later, and other terms used to represent objects with equivalent technical meaning may be used.

[0031] In this disclosure, for ease of description, the terms and names defined in the 3GPP LTE standard are used. However, this disclosure is not limited to the terms and names and can be applied equally to systems based on another standard.

[0032] Figure 1 This is a diagram illustrating the configuration of an LTE system according to an embodiment of the present disclosure.

[0033] refer to Figure 1 As shown in the figure, the radio access network of the LTE system includes Evolved Node Bs (hereinafter referred to as "eNB", "Node B" or "base station") 1-05, 1-10, 1-15, 1-20, Mobility Management Entity (MME) 1-25, and Service Gateway (S-GW) 1-30. User Equipment (hereinafter referred to as UE or terminal) 1-35 accesses the external network through eNB 1-05 to 1-20 and S-GW 1-30.

[0034] exist Figure 1In this context, eNBs 1-05 to 1-20 correspond to existing Node Bs in the UMTS system. The eNB connects to UE 1-35 via a radio channel and performs a more complex role than the existing Node B. In LTE systems, all types of user services, including real-time services, are served via shared channels, such as Voice over IP (VoIP) via the Internet Protocol. Therefore, a means is needed to perform scheduling by collecting UE state information (e.g., buffer state, available transmission power state, and channel state) processed by eNBs 1-05 to 1-20. Typically, one eNB controls multiple cells. For example, to achieve a transmission speed of 100 Mbps, the LTE system uses Orthogonal Frequency Division Multiplexing (hereinafter referred to as "OFDM") as the radio access technology in a 20 MHz bandwidth. Furthermore, an Adaptive Modulation and Coding (hereinafter referred to as "AMC") scheme is applied to determine the modulation scheme and channel coding rate based on the UE's channel state. S-GW 1-30 is a means for providing data bearers and generates or removes data bearers under the control of MME 1-25. The MME is a device that, in addition to the UE's mobility management functions, is responsible for various control functions and is connected to multiple base stations.

[0035] Figure 2 This is a diagram illustrating the radio protocol architecture in an LTE system according to an embodiment of the present disclosure.

[0036] Reference Figure 2 The radio protocols of the LTE system include Packet Data Convergence Protocol (PDCP) 2-05 and 2-40, Radio Link Control (RLC) 2-10 and 2-35, and Media Access Control (MAC) 2-15 and 2-30 in the UE and eNB, respectively. PDCP 2-05 and 2-40 handle operations such as IP header compression / reconstruction. The main functions of PDCP are summarized below.

[0037] -Header compression and decompression: ROHC only

[0038] -Transmit user data

[0039] - Sequential delivery of upper-layer PDUs during the PDCP reconstruction process for RLC AM

[0040] - For separate bearers in the DC (RLC AM only): PDCP PDU routing for transmission and PDCP PDU reordering for reception.

[0041] - Repeated detection of lower-level SDUs during PDCP reconstruction for RLC AM

[0042] - Retransmission of PDCP SDUs during handover for RLC AM, and retransmission of PDCP PDUs during PDCP data recovery for separated bearers in DC.

[0043] - Encryption and decryption

[0044] - Timer-based SDU dropping in the uplink

[0045] Radio Link Control (hereinafter referred to as "RLC") 2-10 and 2-35 perform ARQ operations, etc., by reconfiguring PDCP Packet Data Units (PDUs) to appropriate sizes. The main functions of RLC are summarized below.

[0046] -Transmission of upper-layer PDUs

[0047] - Error correction via ARQ (for AM data transmission only)

[0048] Cascading, splitting, and reassembling of RLC SDUs (for UM and AM data transmission only)

[0049] - Resegmentation of RLC data PDUs (for AM data transmission only)

[0050] - Reordering of RLC data PDUs (for UM and AM data transfer only)

[0051] - Duplicate detection (only for UM and AM data transmission)

[0052] - Protocol error detection (for AM data transmission only)

[0053] -RLC SDU discard (only for UM and AM data transfer)

[0054] -RLC Reconstruction

[0055] MAC 2-15 and 2-30 connect to several RLC layer devices configured in a UE and perform operations such as multiplexing RLC PDUs into MAC PDUs and demultiplexing RLC PDUs from MAC PDUs. The main functions of the MAC are summarized below.

[0056] Mapping between logical channels and transport channels

[0057] - Multiplexing MAC SDUs belonging to one or different logical channels into a transport block (TB) delivered to the physical layer on the transport channel / Demultiplexing MAC SDUs belonging to one or different logical channels from a transport block (TB) delivered to the physical layer on the transport channel.

[0058] - Scheduling Information Report

[0059] - Error correction via HARQ

[0060] Priority processing between logical channels of a UE

[0061] - Prioritization among UEs is performed through dynamic scheduling.

[0062] -MBMS service identifier

[0063] -Transmission format selection

[0064] -filling

[0065] PHY layers 2-20 and 2-25 perform channel coding and modulation of higher-layer data, generating OFDM symbols from the higher-layer data, transmitting OFDM symbols via the radio channel, demodulating OFDM symbols received via the radio channel, performing channel decoding on the OFDM symbols, and transmitting the OFDM symbols to higher layers. Furthermore, Hybrid ARQ (HARQ) is used for additional error correction even in the PHY layer. The receiver uses one bit to indicate whether a packet sent by the transmitter has been received. This is called HARQ ACK / NACK information. Downlink HARQ ACK / NACK information for uplink transmission is transmitted via the Physical Hybrid-ARQ Indicator Channel (PHICH) physical channel. Uplink HARQ ACK / NACK information for downlink transmission can be transmitted via the Physical Uplink Control Channel (PUCCH) or the Physical Uplink Shared Channel (PUSCH) physical channel.

[0066] Meanwhile, the PHY layer can consist of one or more frequencies / carriers. The technique of configuring and using multiple frequencies simultaneously is called carrier aggregation (hereinafter referred to as "CA"). CA technology can significantly increase the transmission rate by additionally using a primary carrier and one or more secondary carriers, instead of using only one carrier for communication between the terminal (or user equipment (UE)) and the base station (E-UTRAN NodeB or eNB). In LTE, the cell within a base station using the primary carrier is called the primary cell (PCell), and the secondary carriers are called secondary cells (SCells).

[0067] Although not shown in the diagram, a Radio Resource Control (RRC) layer exists on the PDCP layer of each of the UE and the base station. The RRC layer can be connected for radio resource control and can exchange measurement-related configuration control messages.

[0068] Figure 3 This is a diagram illustrating the configuration of a next-generation mobile communication system according to an embodiment of the present disclosure.

[0069] refer to Figure 3 As shown in the figure, the radio access network of the next-generation mobile communication system consists of a new radio node B (hereinafter referred to as "NR NB") 3-10 and a new radio core network (NR CN or next-generation core network (NG CN) 3-05). New radio user equipment (hereinafter referred to as "NR UE" or terminal) 3-15 accesses the external network through NR NB 3-10 and NR CN 3-05.

[0070] exist Figure 3 In this context, NR NB3-10 corresponds to the Evolved Node B (eNB) of the existing LTE system. The NR NB connects to NR UE 3-15 via a radio channel and can provide better service than the existing Node B. In next-generation mobile communication systems, all types of user services are served through a shared channel. Therefore, a device is needed to perform scheduling by collecting UE state information (e.g., buffer state, available transmission power state, and channel state) processed by NR NB3-10. Typically, one NRNB controls multiple cells. To achieve ultra-high-speed data transmission compared to existing LTE, the existing maximum bandwidth or greater can be used, and beamforming technology can be additionally applied by using Orthogonal Frequency Division Multiplexing (OFDM) as the radio access technology. Furthermore, an Adaptive Modulation and Coding (AMC) scheme is applied to determine the modulation scheme and channel coding rate based on the UE's channel state. NRCN 3-05 performs functions such as mobility support, bearer configuration, and Quality of Service (QoS) configuration. The NR CN is a device responsible for various control functions in addition to the UE's mobility management functions and connects to multiple base stations. Furthermore, the next-generation mobile communication system can also operate in conjunction with the existing LTE system. The NR CN connects to the MME 3-25 via a network interface. The MME connects to the eNB3-30, which is the existing base station.

[0071] Figure 4 This is a diagram illustrating the radio protocol architecture of a next-generation mobile communication system according to an embodiment of the present disclosure.

[0072] refer to Figure 4 The radio protocols of the next-generation mobile communication system consist of NR SDAPS 4-01 and 4-45, NR PDCP 4-05 and 4-40, NR RLC 4-10 and 4-35, and NR MAC 4-15 and 4-30 in the UE and NR base station, respectively.

[0073] The main functions of NR SDAP 4-01 and 4-45 may include some of the following functions.

[0074] -Transmission of user plane data

[0075] - Mapping between QoS flows and DRB for both DL and UL

[0076] - Mark QoS flow IDs in DL and UL groups

[0077] - Reflective QoS flow for DRB mapping of UL SDAP PDU.

[0078] For SDAP layer devices, RRC messages can be used to configure the UE to use either the SDAP layer device header or the SDAP layer device functionality for each PDCP layer device, each bearer, or each logical channel. If the SDAP header is already configured, the UE can be instructed to update or reconfigure the uplink and downlink QoS flows and data bearer mapping information using the NAS QoS reflective configuration 1-bit indicator (NAS reflective QoS) and AS QoS reflective configuration 1-bit indicator (AS reflective QoS) in the SDAP header. The SDAP header may include QoS flow ID information indicating QoS. QoS information can be used for data processing priority, scheduling information, etc., to support smooth service.

[0079] The main functions of NR PDCP 4-05 and 4-40 may include some of the following functions.

[0080] -Header compression and decompression: ROHC only

[0081] -Transmit user data

[0082] - Ordered delivery of upper-layer PDUs

[0083] -Disordered delivery of upper-layer PDUs

[0084] - Reordering of received PDCP PDUs

[0085] -Repetition detection of lower-level SDUs

[0086] -PDCP SDU retransmission

[0087] - Encryption and decryption

[0088] - Timer-based SDU dropping in the uplink.

[0089] In the above context, the reordering of the NR PDCP device refers to the function of reordering PDCP PDUs received from a lower layer in sequence based on the PDCP sequence number (SN), and may include the function of delivering data to a higher layer in the reordered sequence, or may include the function of directly delivering data without regard to the sequence, may include the function of reordering the sequence and recording lost PDCP PDUs, may include the function of sending a status report of lost PDCP PDUs to the transmitting side, and may include the function of requesting retransmission of lost PDCP PDUs.

[0090] The main functions of NRRLC4-10 and 4-35 may include some of the following functions.

[0091] -Transmission of upper-layer PDUs

[0092] - Ordered delivery of upper-layer PDUs

[0093] -Disordered delivery of upper-layer PDUs

[0094] -Error correction via ARQ

[0095] Cascading, splitting, and reassembling of RLC SDUs

[0096] -Re-segmentation of RLC data PDUs

[0097] - RLC data PDU reordering

[0098] -Duplicate detection

[0099] -Protocol error detection

[0100] -RLC SDU discard

[0101] -RLC Reconstruction

[0102] In the above context, the sequential delivery of NR RLC devices refers to the function of sequentially delivering RLC SDUs received from lower layers to higher layers. This may include the function of reassembling and delivering several RLC SDUs if an original RLC SDU is split into several RLC SDUs and received; the function of reordering received RLC PDUs based on RLC sequence number (SN) or PDCP sequence number (SN); the function of reordering multiple sequences and recording lost RLC PDUs; the function of sending a status report for lost RLC PDUs to the transmitting side; the function of requesting retransmission of lost RLCPDUs; and the function of sequentially delivering only RLC SDUs to higher layers up to the lost RLC SDU if a lost RLC SDU exists. Alternatively, it may include the function of sequentially delivering all RLC SDUs received before the start of a given timer to higher layers if a given timer has expired, even if a lost RLC SDU exists. Furthermore, as described above, RLC PDUs can be processed in the order they are received (regardless of their sequence numbers) or in the order they arrive, and can be delivered to the PDCP device regardless of order (out-of-order delivery). In the case of fragmentation, fragments stored in a buffer or subsequently received in sequence can be received and reconfigured into a complete RLC PDU, which can then be processed and delivered to the PDCP device. The NR RLC layer may not include concatenation functionality. This functionality can be implemented in the NR MAC layer or replaced by multiplexing functionality of the NR MAC layer.

[0103] In the above, out-of-order delivery of NR RLC devices refers to the function of directly delivering RLC SDUs received from lower layers to higher layers regardless of their order. If an original RLC SDU is split into multiple RLC SDUs and received, the function may include reassembling and delivering multiple RLC SDUs, and may include storing the RLCSN or PDCP SN of the received RLC PDUs, sorting the sequence, and recording lost RLC PDUs.

[0104] NR MACs 4-15 and 4-30 can connect to several NR RLC layer devices configured in a single UE. The main functions of an NR MAC may include some of the following.

[0105] Mapping between logical channels and transport channels

[0106] - MAC SDU multiplexing / demultiplexing

[0107] - Scheduling Information Report

[0108] - Error correction via HARQ

[0109] Priority processing between logical channels of a UE

[0110] - Prioritization among UEs is performed through dynamic scheduling.

[0111] -MBMS service identifier

[0112] -Transmission format selection

[0113] -filling

[0114] NR PHY layers 4-20 and 4-25 can perform the following operations: channel coding and modulation of higher-layer data, generating data into OFDM symbols, transmitting OFDM symbols via a wireless channel or demodulating OFDM symbols received via a wireless channel, channel decoding of OFDM symbols, and delivering OFDM symbols to higher layers.

[0115] Figure 5 This is a diagram illustrating a method for applying segmentation to RRC control messages via the downlink in an NR system according to embodiments of the present disclosure. RRCReconfiguration and RRCResume messages can be used as examples of RRC control messages, and specific DL RRC control messages that require segmentation due to their large size can also be used as examples of RRC control messages. In the following disclosure, RRCReconfiguration has been generalized and described as an example, but this does not limit the scope of the present disclosure.

[0116] Basically, when the UE is already connected to the serving base station (eNB or gNB) 5-02 (5-05), the UE 5-01 needs to receive configuration information for sending data to and receiving data from the base station. In step 5-10, base stations 5-02 and 5-03 decide to deliver an RRCReconfiguration message to the UE and generate corresponding information. As shown in the figure, in the state of dual connectivity (hereinafter referred to as DC), the following situations may occur depending on how the RRCReconfiguration will be delivered.

[0117] Case 1: If the master node (MN) generates an RRC message that includes MCG configuration information, then in this case, the base station delivers the generated RRC message through SRB1.

[0118] Scenario 2: If the MN receives the secondary node (SN) configuration information and generates an RRC message including MCG / SCG configuration information, then in this case, the base station delivers the generated RRC message through SRB1.

[0119] Case 3: If the SN generates an RRC message that includes SCG configuration information, then in this case, the base station delivers the generated RRC message via SRB3.

[0120] In steps 5-15, when the RRC control message generated in step 5-10 is larger than 9000 bytes, i.e., the maximum size of a PDCP SDU, the base station can apply segmentation to the corresponding RRC control message (e.g., an RRCReconfiguration message). That is, the entire RRCReconfiguration message can be segmented into segments of 9000 bytes each, and the final segment can be the size remaining after subtracting the sum of the sizes of the segmented RRC messages (each segmented into 9000-byte segments) from the total message size. In step 5-20, the base station can deliver the generated segmented RRC messages (segmented RRCReconfiguration messages) to the UE one by one. In this case, the delivered segmented RRC messages need to be delivered sequentially according to their sequence numbers and should not be interrupted by another RRC message. That is, when a segmented RRC message is delivered, another RRC message is not delivered. The UE can store the delivered segmented RRC messages. In steps 5-25, after receiving all the segmented RRC messages, the UE can recover the entire RRC message information by decoding and reassembling the received segmented RRC messages.

[0121] Figure 6 This is a diagram illustrating a method for applying segmentation to downlink RRC messages in an NR system according to embodiments of the present disclosure. The detailed structure of the segmented RRC message is described with reference to the accompanying drawings, and the RRCReconfiguration message is described as an example.

[0122] If segmentation based on DL DCCH messages is applied, a new DL-segmented RRC message can be introduced. For example, a new DL DCCH message called DLDedicatedMessageSegment can be introduced and used to deliver the DL-segmented RRC. When the completed DL DCCH message 6-05, for example, a DL DCCH message including an RRCReconfiguration message, is greater than 9000 bytes, the base station can segment the entire RRCReconfiguration message into 8996 bytes, as in 6-25 and 6-55, and can generate a segmented message of 9000 bytes by adding a 4-byte DL-segmented RRC message header to the segmented message. In this case, the size of the message header and the size of the segmented RRC message can vary depending on the size of the introduced fields. The final segmented message 6-85 can have a size corresponding to the size obtained by subtracting the sum of the sizes of the segmented messages with a length of 9000 bytes from the total size.

[0123] The 6-bit segments 6-10, 6-40, and 6-70 (for the CHOICE structure and DLDedicatedMessageSegment message indication) used for DL ​​DCCH type configuration and the 4-bit segmentation indexes 6-15, 6-45, and 6-75 used for the corresponding segmented UE capability information message can be included in the header of the DL segmented RRC message. The segmentation index is an identifier indicating which segment the corresponding segmented RRC message corresponds to. Figure 6 The example corresponds to the case where the maximum segment size has been set to 16. The number of bits can vary depending on the maximum setting value. The corresponding identifier can always be included, but it can be omitted because the corresponding segments can be delivered sequentially via the PDCP SN. In contrast, an indicator indicating whether a particular segment is the final segment (LastSegment) needs to be included in the corresponding header. If the corresponding LastSegment indicator is indicated as 0, indicating that the corresponding segment is not the final segment, the UE receiving the corresponding message can know that the corresponding packet has a maximum size. Furthermore, padding bits 6-35, 6-65, and 6-95 for byte alignment can be included in the header. The padding bits can vary depending on the previous header, segment size, etc. Additionally, a 15-bit length field indicating the length of the segmented RRC message can be included in the header. This means the number of bits used to indicate 8996 bytes.

[0124] In this method, if the PDCP SDU size is adjusted to 9000 bytes, a PDCP SN can be added and a PDCP PDU can be generated.

[0125] In the following embodiments of this disclosure, if segmentation is applied to DL RRC control messages, particularly RRCReconfiguration messages, the overall operation of delivering the corresponding messages via signaling radio bearers 1 (SRB1) and SRB3 is described, i.e., the existing transmission method. Furthermore, UE and base station operations are proposed based on possible scenarios when the corresponding operation occurs. These scenarios could be RLF, RRC release, RRC recovery, HO, or SCG change. Detailed operations are described in each of the following embodiments.

[0126] Figure 7 This diagram illustrates the operation of the UE and base station in the case of segmentation applied to downlink RRC messages according to embodiments of the present disclosure, and specifically describes the operation under specific circumstances. RRCReconfiguration and RRCResume messages can be used as examples of RRC control messages, and specific DL RRC control messages that require segmentation due to large scale can also be used as examples of RRC control messages. In the following disclosure, RRCReconfiguration is generalized and described. Furthermore, in describing some embodiments of the present disclosure, it is assumed and described that dual connectivity (DC) has been configured, but this is merely illustrative and does not limit the scope of the present disclosure. Embodiments of the present disclosure can also be applied to UE and base station operation without DC configuration.

[0127] Basically, with the UE already connected to the serving base station (eNB or gNB) 7-02 (7-05), the UE 7-01 needs to receive configuration information for sending data to and receiving data from the base station. In this step, it is assumed that DC has been configured and the MN and SN are already connected. In step 7-10, base stations 7-02 and 7-03 decide to deliver an RRCReconfiguration message to the UE and generate corresponding information. As shown in the figure, depending on how RRCReconfiguration will be delivered in the state of configured dual connectivity (hereinafter referred to as DC), the following situations may occur.

[0128] Case 1: If the master node (MN) generates an RRC message that includes MCG configuration information, then in this case, the base station delivers the generated RRC message via SRB1.

[0129] Scenario 2: If the MN receives the secondary node (SN) configuration information and generates an RRC message including MCG / SCG configuration information, then in this case, the base station delivers the generated RRC message through SRB1.

[0130] Case 3: If the SN generates an RRC message that includes SCG configuration information, then in this case, the base station delivers the generated RRC message via SRB3.

[0131] In steps 7-15, when the RRC control message generated in step 7-10 is larger than 9000 bytes, i.e., the maximum size of a PDCP SDU, the base station can apply segmentation to the corresponding RRC control message (e.g., an RRCReconfiguration message). That is, the entire RRCReconfiguration message can be segmented into segments of 9000 bytes each, and the final segment can be the size remaining after subtracting the sum of the sizes of the segmented RRC messages (each segmented into 9000-byte segments) from the total message size. The base station operation is described in detail below based on the above.

[0132] -MN performs a splitting operation on the generated RRCReconfiguration messages (case 1 and case 2).

[0133] □ Check whether the generated RRC message is for MN or SN.

[0134] ◇In the case of RRC messages for MN

[0135] ○ Include / generate segmented RRCReconfiguration messages in DLDedicatedMessageSegment

[0136] ○ Deliver multiple DLDedicatedMessageSegment messages, which already fully contain the entire RRCReconfiguration, via SRB1.

[0137] ○ Perform a segmentation operation on the generated RRCReconfiguration message by sequentially delivering the SN via SRB1 without interrupting another DL RRC message (Case 3).

[0138] □ Check whether the generated RRC message is for MN or SN.

[0139] ◇If the generated RRC message is an RRC message for the SN and SRB3 has been configured

[0140] ○ Include / generate segmented RRCReconfiguration messages in DLDedicatedMessageSegment

[0141] ○ Deliver multiple DLDedicatedMessageSegment messages that completely contain the entire RRCReconfiguration via SRB3.

[0142] ○ Deliver sequentially via SRB3 without interrupting another DL RRC message.

[0143] As described above, in steps 7-15, the base station can deliver the generated segmented RRC messages (segmented RRCReconfiguration messages) to the UE one by one via the configured SRB. In this case, the delivered segmented RRC messages need to be delivered sequentially according to their sequence number (or segment index) and should not be interrupted by another RRC message. That is, when a segmented RRC message is delivered, another RRC message is not delivered. This disclosure proposes the operation of the UE and the base station if a specific situation occurs before the segmented RRC (DLDedicatedMessageSegment) is fully delivered in steps 7-15. For example, if there are a total of N segmented RRC messages, the proposed UE and base station operation exists when a specific situation occurs in the state where (N-1) segments have been delivered to the UE via the configured SRB and the last Nth segmented RRC message has not been delivered to the UE. For example, the above situation could be RLF, RRC release, RRC recovery, HO, SCG change, etc.

[0144] For reference, already referenced Figure 5 The scenario described below illustrates a situation where all segmented RRC messages have been delivered to the UE without any issues. The following embodiments describe different scenarios in more detail. Simplified operations are depicted in the accompanying drawings. Currently, discussion of RRC messages stored in the RRC layer is unnecessary because the operation is performed under the premise that, in the RRC layer, RRC messages are either immediately sent to lower layers upon occurrence without being stored, or processed immediately upon receipt. However, when RRC segmentation is introduced, segmented RRC messages can be stored in the RRC layer, and operations are required to explicitly discard data stored in the RRC layer under specific circumstances.

[0145] The first scenario is a Radio Link Failure (RLF) caused by a radio link problem where the UE fails to receive all the segmented RRC messages (7-20). The UE can receive a signal from the physical layer indicating that it cannot receive service from the base station (MeNB / MgNB) while sending and receiving data from the base station, such as "Out of Synchronization (OOS)". If the number of times the signal is received is N310, the UE identifies a problem with the radio connection with the base station (MeNB / MgNB) and operates timer T310. While the timer is running, the UE does not perform any operations to restore the radio link. Furthermore, timer T310 stops when the number of times a "synchronization" indicator is received from the physical layer is N311 before timer T310 expires, or when an RRCReconfiguration message for re-establishing the connection is received. If timer T310 expires, the UE declares an RLF (7-20) and executes the RRC connection reconstruction procedure (7-25). The UE performs cell selection, MAC reset, RB suspension, PDCP reconstruction, etc., as part of the RRC connection reconstruction procedure. Furthermore, when the RRC connection re-establishment process begins, the UE operates timer T311, and does not perform a radio link recovery operation while the timer is operating. If RRC connection re-establishment is not performed while timer T311 is operating and timer T311 expires, the UE's state transitions to the RRC idle state. Normally, a PDCP re-establishment operation is performed when the corresponding operation occurs. However, this disclosure proposes an operation in steps 7-25 to discard the segmented RRC messages stored in its RRC layer. The discarded segmented RRC messages may correspond to DL segmented RRC messages or UP segmented RRC messages or both. Furthermore, in the corresponding steps, the base station, like the UE, discards the segmented RRC messages stored in its RRC layer.

[0146] The second scenario is where the base station transitions the UE's state to an RRC inactive state if the UE has not received all the segmented RRC messages (7-30). In this case, the base station can deliver the RRCLease message by including suspendConfig (i.e., configuration information for the inactive mode) in the RRCLease message. After receiving the RRCLease in step 7-30, the UE's state transitions to the RRC INACTIVE state according to the configured RRC INACTIVE conditions. In step 7-35, the base station performs the RRC recovery procedure in response to a request from the UE or due to a triggering at a specific time by the base station. The UE that has received the RRCLease message delivered by the base station in step 7-35 performs the operation of re-establishing the PDCP configured in SRB1 and SRB3 as a recovery operation and recovers the corresponding SRB1 / 3. This disclosure proposes that the UE discard the segmented RRC messages stored in the RRC layer in this step. The discarded segmented RRC messages may correspond to DL segmented RRC messages or UL segmented RRC messages, or both. The following sentence can be incorporated into the standard document as an example.

[0147]

[0148] The third scenario is where the base station transitions the UE to an RRC idle state if the UE has not received all the segmented RRC messages (7-40). In this case, the base station includes a configuration indicating a transition to IDLE mode in the RRCRelease message. The UE, having received the corresponding message, performs an operation to release all configured radio bearers (RBs). This means releasing the RLC associated with the RB and releasing the SDAP, PDCP, or MAC configurations for all configured RBs. This disclosure proposes in this step that the UE discards the segmented RRC messages stored in the RRC layer. The discarded segmented RRC messages can be DL segmented RRC messages, UL segmented RRC messages, or both. The following sentence can be incorporated into the standard document as an example.

[0149]

[0150] The fourth scenario is when the base station hands the UE to another serving cell or changes the PSCell if the UE has not received all the segmented RRC messages (7-45). In other words, the fourth scenario outlines UE operations during handover and mobility situations. If the handover indication is enabled, the UE discards the DL segmented RRC messages for SRB1 and SRB3, and discards the DL segmented RRC message for SRB3 in the case of an SCG change. Furthermore, the following scenarios are also possible.

[0151] 1. If SRBToAdd includes DiscardOnPDCP for SRB1 / 3 of the received RRCReconfiguration message, then discard the PDCP and DLDedicatedMessageSegment data of the RRC.

[0152] 2. Alternatively, introduce a new IE (e.g., discardOnRRC) for discarding DLDedicatedMessageSegment.

[0153]

[0154] In the foregoing, the scenario where the UE receives another RRC message even though it has not received all the segmented RRC messages can correspond to the situation where, if interruption is not permitted in the same SRB, handover / mobility configuration is configured for the UE via another SRB. For example, this could correspond to the UE receiving a segmented RRC message via SRB1 and receiving a request to change the PSCell via SRB3, or receiving a segmented RRC message via SRB3 or a handover indication via SRB1. Hereinafter, the operation of the UE and base station according to various embodiments of the present disclosure is described with reference to the accompanying drawings. Throughout this specification, some components in the drawings may be omitted without departing from the scope of the present disclosure, or modifications may be made in various ways.

[0155] Figure 8 This is a diagram illustrating UE operation according to a first embodiment of the present disclosure, wherein segmented RRC control messages are generated and delivered via a specific SRB.

[0156] In step 8-05, the UE performs the RRC connection procedure together with the serving base station, and in step 8-10, it reports the capabilities supported by the UE to the corresponding base station. That is, in step 8-10, the UE can receive a request from the base station instructing the UE to report UE capability information (UECapabilityEnquiry message). This message may include filtering information for the UE capability information (RAT type, frequency information, etc.). When the UECapabilityEnquiry message is received, the UE generates its own UE capability message (UE capability information) in response to the base station's UE capability request, and when the corresponding message is larger than 9000 bytes, i.e., the maximum size of a PDCPPDU, segmentation is applied to the UE capability information. In other words, the entire UE capability information message can be segmented into segments of 9000 bytes each, and the final segment can be the size remaining after subtracting the sum of the sizes of the segmented 9000-byte RRC messages from the total message size.

[0157] In steps 8-15, the UE can receive a DL-dedicatedMessageSegment (DLDedicatedMessageSegment) segmented from the RRCReconfiguration message from the base station. In steps 8-20, the UE identifies which SRB the received RRC message was delivered through.

[0158] When the received RRC message is received via SRB1 based on the delivered SRB type in step 8-25, in step 8-30, the UE delivers the received DL-segmented RRC message to the UE's RRC layer. In this case, the RRC message received via the corresponding SRB1 is managed separately, ensuring that the RRC message is not mixed with RRC messages received via another SRB. In step 8-35, after receiving all DL-segmented RRC messages, the UE performs decoding and restores the DL-segmented RRC messages to RRCReconfiguration messages, i.e., the original DL RRC messages. In the above, the UE can recognize that the received DL-segmented RRC message is the last one by identifying the last segmentation indicator in the DL-segmented RRC message. In step 8-40, the UE decodes and interprets the restored RRCReconfiguration message and applies the RRC configuration information included therein.

[0159] When the received RRC message is received via SRB3 based on the delivered SRB type in step 8-25, the UE delivers the received DL-segmented RRC message to the UE's RRC layer in step 8-45. In this case, the RRC message received via the corresponding SRB3 is managed separately, ensuring that the RRC message is not mixed with RRC messages received via another SRB. In step 8-50, after receiving all DL-segmented RRC messages, the UE performs decoding and restores the DL-segmented RRC messages to RRCReconfiguration messages, i.e., the original DL RRC messages. In the above, the UE can recognize that the received DL-segmented RRC message is the last one by identifying the last segmentation indicator in the DL-segmented RRC message. In step 8-55, the UE decodes and interprets the restored RRCReconfiguration message and applies the RRC configuration information included therein.

[0160] Figure 9 This is a diagram illustrating UE operation according to a second embodiment of the present disclosure when a segmented RRC control message is generated and delivered via a specific SRB and an RLF occurs.

[0161] In step 9-05, the UE performs the RRC connection procedure together with the serving base station, and in step 9-10, it reports the capabilities supported by the UE to the corresponding base station. That is, in step 9-10, the UE can receive a request from the base station instructing the UE to report UE capability information (UECapabilityEnquiry message). This message may include filtering information for the UE capability information (RAT type, frequency information, etc.). When the UECapabilityEnquiry message is received, the UE generates its own UE capability message (UE capability information) in response to the base station's UE capability request, and when the corresponding message is larger than 9000 bytes, i.e., the maximum size of a PDCPPDU, segmentation is applied to the UE capability information. In other words, the entire UE capability information message can be segmented into segments of 9000 bytes each, and the final segment can be the size remaining after subtracting the sum of the sizes of the segmented 9000-byte RRC messages from the total message size.

[0162] In steps 9-15, the UE can receive DL-dedicatedMessageSegments (DLDedicatedMessageSegments) from the RRCReconfiguration message from the base station and can store the received DL-dedicatedMessageSegments. In steps 9-20, the UE identifies which SRB the received RRC message was delivered by. In this embodiment, a Radio Link Failure (RLF) is considered in the case where the final segment of the DL-dedicatedMessageSegment was not received.

[0163] In steps 9-25, the UE can identify in which node an RLF (MCG RLF or SCG RLF) occurred. If only an MCG RLF occurred, the UE performs an MCG RLF operation in step 9-30. That is, if split SRB1 is not configured, the UE discards all RRC splits received through or stored in SRB1. For cases where split SRB1 is configured, the operation differs based on the link state identified in the SCG. In step 9-35, if the UL split RRC message was already stored in the UE's RRC layer when the MCG RLF occurred, the UE can also discard all stored UL split RRC messages. Furthermore, the following cases can also be considered.

[0164] □ MCG RLF occurs when SCG RLF occurs (no SCG link connection).

[0165] ◇ Re-establish PDCP for SRB1 and discard DLDedicatedMessageSegment

[0166] □ MCG RLF occurs when SCG is configured (SCG link exists).

[0167] Option 1: Re-establish PDCP for SRB1 and discard DLDedicatedMessageSegment

[0168] Option 2: Re-establish PDCP for SRB1 and SRB3, and discard DLDedicatedMessageSegment for SRB1 and SRB3.

[0169] □MCG RLF occurs when SCG is not configured.

[0170] ◇ Re-establish PDCP for SRB1 and discard DLDedicatedMessageSegment

[0171] In steps 9-25, the UE identifies in which node an RLF (MCG RLF or SCG RLF) occurred. If only an SCG RLF occurred, then in step 9-40, the UE performs an SCG RLF operation. That is, the UE discards all RRC segments received or stored in SRB3. In step 9-45, if the UL segmented RRC message was already stored in the UE's RRC layer when the MCG RLF occurred, the UE can also discard all stored UL segmented RRC messages.

[0172] In steps 9-25, the UE identifies which node the RLF (MCG RLF or SCG RLF) occurred in. If both MCG RLF and SCG RLF occurred, then in steps 9-50, the UE performs the following RLF operation.

[0173] □ Discard SRB1 RRC segments without considering split SRB1 and unsplit SRB1.

[0174] □ Discard SRB3 RRC segmentation

[0175] In steps 9-55, if the UL segmented RRC message has already been stored in the UE's RRC layer when the RLF occurs, the UE can also discard all stored UL segmented RRC messages.

[0176] Figure 10 This is a diagram illustrating UE operation according to a third embodiment of the present disclosure when a segmented RRC control message is generated and delivered via a specific SRB and instructs an RRC state transition.

[0177] In step 10-05, the UE performs the RRC connection procedure together with the serving base station, and in step 10-10, it reports the capabilities supported by the UE to the corresponding base station. That is, in step 10-10, the UE can receive a request from the base station instructing the UE to report UE capability information (UECapabilityEnquiry message). This message may include filtering information for the UE capability information (RAT type, frequency information, etc.). When the UECapabilityEnquiry message is received, the UE generates its own UE capability message (UE capability information) in response to the base station's UE capability request, and when the corresponding message is larger than 9000 bytes, i.e., the maximum size of a PDCP PDU, segmentation is applied to the UE capability information. In other words, the entire UE capability information message can be segmented into segments of 9000 bytes each, and the final segment can be the size remaining after subtracting the sum of the sizes of the segmented 9000-byte RRC messages from the total message size.

[0178] In steps 10-15, the UE can receive DL-dedicatedMessageSegments (DLDedicatedMessageSegments) from the RRCReconfiguration message from the base station and can store the received DL-dedicatedMessageSegments. In steps 10-20, the UE identifies which SRB the received RRC message was delivered by. In this embodiment, the case of receiving an RRC state transition indication in the state of the last segment of the DL-dedicatedMessageSegment without having received the DL-dedicatedMessageSegment is considered.

[0179] In steps 10-25, the UE can receive an RRC release or RRC recovery message from the base station and perform different operations depending on which message is received. When an RRC release message indicating a transition to RRC idle is received, in steps 10-30, the UE performs a release operation on all configured SRBs (SRB1 and SRB3) and discards received or stored DL RRC segments. Furthermore, in steps 10-35, if a UL segmented RRC message was stored in the UE's RRC layer when the RRC idle indication occurred, the UE also discards all stored UL segmented RRC messages. Additionally, the UE performs a release operation on all configured RBs. This operation means releasing the RLC associated with the RB and releasing the SDAP, PDCP, or MAC configurations for all configured RBs. Furthermore, after the UE receives an RRC release message indicating a transition to RRC inactivity in steps 10-25 and the UE's state transitions to inactivity, if the UE has already received an RRC recovery message, then in steps 10-30, the UE performs a release operation on all configured SRBs (SRB1 and SRB3) and discards any received or stored DL RRC segments. Additionally, in steps 10-35, if a UL segmented RRC message was stored in the UE's RRC layer when an RRC idle indication occurred, the UE also discards all stored UL segmented RRC messages.

[0180] If no RRC message indicating an RRC idle or inactive transition is received in steps 10-25, then in steps 10-40, the UE continues to receive segmented RRC messages from the received SRB, receives the last segment, and restores the corresponding message to the original RRC message by decoding the corresponding message. In steps 10-45, the UE applies the configuration in the restored RRC message.

[0181] Figure 11 This is a diagram illustrating UE operation according to a fourth embodiment of the present disclosure when a segmented RRC control message is generated and delivered via a specific SRB and indicates mobility, i.e., a handover or PSCell change is indicated via the RRC message.

[0182] In step 11-05, the UE performs the RRC connection procedure together with the serving base station, and in step 11-10, it reports the capabilities supported by the UE to the corresponding base station. That is, in step 11-10, the UE can receive a request from the base station instructing the UE to report UE capability information (UECapabilityEnquiry message). This message may include filtering information for the UE capability information (RAT type, frequency information, etc.). When the UECapabilityEnquiry message is received, the UE generates its own UE capability message (UE capability information) in response to the base station's UE capability request, and when the corresponding message is larger than 9000 bytes, i.e., the maximum size of a PDCP PDU, segmentation is applied to the UE capability information. In other words, the entire UE capability information message can be segmented into segments of 9000 bytes each, and the final segment can be the size remaining after subtracting the sum of the sizes of the segmented 9000-byte RRC messages from the total message size.

[0183] In steps 11-15, the UE can receive DL-dedicatedMessageSegments (DLDedicatedMessageSegments) from the RRCReconfiguration message from the base station and can store the received DL-dedicatedMessageSegments. In steps 11-20, the UE identifies which SRB the received RRC message was delivered by. In this embodiment, the case of receiving mobility control in the state before the final segmentation of the DL-dedicatedMessageSegment has been received is considered. This may include cases indicating handover or PSCell change.

[0184] In steps 11-25, the UE can receive a ReconfigurationWithSync message included in another RRCReconfiguration message from the base station. A handover or PSCell change operation can be indicated via the corresponding message. If the UE receives a handover indication in step 11-30, then in step 11-35, the UE discards all DL-segmented RRC messages received or stored in SRB1 and SRB3. Furthermore, in step 11-40, if UL-segmented RRC messages are stored in the UE's RRC layer, the UE also discards all stored UL-segmented RRC messages. In the case of an SCG change as a result of the check in step 11-30, in step 11-45, the UE discards DL-segmented RRC messages received or stored in SRB3. Furthermore, in step 11-50, if UL-segmented RRC messages are stored in the UE's RRC layer, the UE also discards all stored UL-segmented RRC messages. Additionally, the UE performs the following operations when it receives the following indication from the base station.

[0185] 1. If the SRBToAdd of the received RRCReconfiguration message SRB1 / 3 includes the discarding of PDCP, then the UE discards the PDCP data and the RRC DLDedicatedMessageSegment.

[0186] 2. Alternatively, the UE may receive a new IE (e.g., discardOnRRC) for discarding the DLDedicatedMessageSegment.

[0187] In the above context, if interruptions are not allowed within the same SRB, the situation where the UE receives another RRC message before it has fully received all the segmented RRC messages can correspond to a handover / mobility configuration indication via another SRB. For example, this could correspond to the UE receiving a segmented RRC message via SRB1 and a request to change the PSCell via SRB3, or receiving a segmented RRC message via SRB3 and a handover indication via SRB1.

[0188] If the UE does not receive ReconfigurationWithSync in steps 11-25, then in steps 11-55, the UE continues to receive segmented RRC messages from the received SRB, receives the final segment, and then restores the corresponding message to the original RRC message by decoding the corresponding message. In steps 11-60, the UE applies the configuration in the restored RRC message.

[0189] Figure 12 This is a diagram illustrating base station operation according to an embodiment of the present disclosure.

[0190] In step 12-05, the serving base station (eNB or gNB) can establish a connection with the UE. In this step, the DC is configured so that the MN and SN can have their states of being connected to the UE. In step 12-10, the base station decides to deliver an RRCReconfiguration message to the UE and generates the corresponding information. As shown in the figure, in the state of configured dual connectivity (hereinafter referred to as DC), the following situations may occur depending on how the RRCReconfiguration will be delivered.

[0191] Case 1: If the master node (MN) generates an RRC message that includes MCG configuration information, then in this case, the base station delivers the generated RRC message via SRB1.

[0192] Scenario 2: If the MN receives the secondary node (SN) configuration information and generates an RRC message including MCG / SCG configuration information, then in this case, the base station delivers the generated RRC message through SRB1.

[0193] Case 3: If the SN generates an RRC message that includes SCG configuration information, then in this case, the base station delivers the generated RRC message via SRB3.

[0194] In steps 12-15, the base station checks whether the RRC control message generated in step 12-10 is greater than 9000 bytes, i.e., the maximum size of the PDCP SDU (12-20). When the generated RRC message is greater than 9000 bytes, in step 12-25, the base station identifies whether the corresponding message was generated from the MN or the SN. If the corresponding message was generated from the MN, then in step 12-30, the base station generates a segmented RRCReconfiguration message, contains the segmented RRCReconfiguration message within a DLDedicatedMessageSegment, and delivers multiple DLDedicatedMessageSegment messages containing all RRC reconfigurations via SRB1. In this case, the base station sequentially delivers multiple DLDedicatedMessageSegment messages via SRB1 without interrupting another DL RRC message. If the identification result of the message generation node in steps 12-25 is that the corresponding message is a message generated from the SN, that is, the corresponding message is an RRC message for the SN, and SRB3 has been configured in steps 12-40, then the base station includes and generates a segmented RRCReconfiguration message in the DLDedicatedMessageSegment, and delivers multiple DLDedicatedMessageSegment messages containing all RRCReconfigurations through the following steps: SRB3. In this case, the base station delivers multiple DLDedicatedMessageSegment messages sequentially through SRB3 without interrupting another DL RRC message.

[0195] When the size of the generated downlink RRC message, as a result of checking it in steps 12-20, is less than 9000 bytes, the base station delivers the generated RRC message via the SRB, which has already generated the corresponding message. Subsequently, in steps 12-55, the base station, based on the configured information, performs data transmission and reception together with the UE.

[0196] Figure 13This is a diagram illustrating the configuration of a UE according to an embodiment of the present disclosure.

[0197] like Figure 13 As shown, the UE according to an embodiment of the present disclosure includes a transceiver unit 13-05, a controller 13-10, a multiplexing and demultiplexing unit 13-15, various higher-layer processors 13-20 and 13-25, and a control message processor 13-30.

[0198] Transceiver unit 13-05 receives data and given control signals through the forward channel of the serving cell and transmits data and given control signals through its backward channel. If multiple serving cells are configured, transceiver unit 13-05 performs data transmission and reception, as well as control signal transmission and reception, through multiple serving cells. Multiplexing and demultiplexing unit 13-15 is used to multiplex data generated by higher-layer processors 13-20, 13-25, or control message processor 13-30, or to demultiplex data received from transceiver unit 13-05, and deliver the data to the appropriate higher-layer processor 13-20, 13-25, or control message processor 13-30. Control message processor 13-30 sends and receives control messages from the base station and takes the necessary actions. In this case, the necessary actions include functions for processing control messages (e.g., RRC messages and MAC CE), and include reporting CBR measurements and receiving RRC messages for resource pools, as well as UE operations. Higher-layer processors 13-20 and 13-25 represent DRB devices and can be configured for each service. Higher-layer processors 13-20 and 13-25 process data generated in user services such as File Transfer Protocol (FTP) or Voice over Internet Protocol (VoIP) and deliver the data to multiplexing and demultiplexing unit 13-15, or process data received from multiplexing and demultiplexing unit 13-15 and deliver the data to higher-layer service applications. Controller 13-10 recognizes scheduling commands received through transceiver unit 13-05, such as backward authorization, and controls transceiver unit 13-05 and multiplexing and demultiplexing unit 13-15 to perform backward transmissions at appropriate timings using appropriate transmission resources. Furthermore, while the UE has been described above as consisting of multiple blocks performing different functions, this is merely an embodiment, and the disclosure is not substantially limited thereto. For example, the functions performed by demultiplexing unit 13-15 may be performed by controller 13-10 itself.

[0199] Figure 14 This is a diagram illustrating the configuration of a base station according to an embodiment of the present disclosure.

[0200] Figure 14The base station device includes a transceiver unit 14-05, a controller 14-10, a multiplexing and demultiplexing unit 14-20, a control message processor 14-35, various higher-layer processors 14-25 and 14-30, and a scheduler 14-15.

[0201] Transceiver unit 14-05 transmits data and given control signals via a forward carrier and receives data and given control signals via a backward carrier. If multiple carriers are configured, transceiver unit 14-05 performs data transmission and reception, as well as control signal transmission and reception, via multiple carriers. Multiplexing and demultiplexing unit 14-20 is used to multiplex data generated by higher-layer processors 14-25, 14-30, or control message processor 14-35, or to demultiplex data received from transceiver unit 14-05, and delivers the data to the appropriate higher-layer processor 14-25, 14-30, control message processor 14-35, or controller 14-10. Control message processor 14-35 generates a message to be delivered to the UE in response to instructions from the controller and delivers the message to the lower layer. Higher-layer processors 14-25 and 14-30 can be configured for each service component of each UE, and process data generated in user services such as FTP or VoIP, delivering the data to the multiplexing and demultiplexing unit 14-20, or process data received from the multiplexing and demultiplexing unit 14-20 and deliver the data to the higher-layer service application. Scheduler 14-15 allocates transmission resources to the UE at appropriate timing by considering the UE's buffer state, channel state, UE activity time, etc., and enables the transceiver unit to process signals transmitted by the UE or send signals to the UE.

[0202] In the detailed embodiments described above, components included in this disclosure have been represented in singular or plural form according to the proposed detailed embodiments. However, for ease of description, singular or plural expressions have been suitably chosen, and this disclosure is not limited to singular or plural components. Although a component has been represented in plural form, it can be configured in singular form. Although a component has been represented in singular form, it can be configured in plural form.

[0203] Although detailed embodiments have been described in the detailed description of this disclosure, this disclosure can be modified in various ways without departing from its scope. Therefore, the scope of this disclosure should not be limited to the foregoing embodiments, but should be defined by the claims and their equivalents.

Claims

1. A method performed by a user equipment (UE) in a communication system, comprising: Receive UE capability query messages from the base station; Based on the fact that the size of the UE capability information message is greater than the maximum size of the Packet Data Convergence Protocol (PDCP) Service Data Unit (SDU), at least one segment of the UE capability information message is sent to the base station. Receive at least one segment of a first Radio Resource Control (RRC) message from the base station; Store at least one segment of the received first RRC message; Receive an RRC release message from the base station indicating a transition to the RRC idle state; as well as Based on the RRC release message indicating a transition to the RRC idle state, at least one segment of the stored first RRC message is discarded.

2. The method according to claim 1, wherein, The size of the first RRC message is greater than the maximum size of the Packet Data Convergence Protocol (PDCP) Service Data Unit (SDU).

3. The method according to claim 1, wherein, The at least one segment of the first RRC message includes at least one segment of the RRCReconfiguration message or at least one segment of the RRCResume message.

4. A method performed by a base station in a communication system, comprising: Send a UE capability query message to the user equipment (UE); Based on the fact that the size of the UE capability information message is greater than the maximum size of the Packet Data Convergence Protocol (PDCP) Service Data Unit (SDU), at least one segment of the UE capability information message is received from the UE. Generate a first Radio Resource Control (RRC) message to be sent to the UE; Generate at least one segment of the first RRC message; as well as Send at least one segment of the first RRC message to the UE; Generate an RRC release message indicating the transition to the RRC idle state; as well as Send the RRC release message to the UE. The RRC release message is used to instruct the UE to discard at least one segment of the first RRC message stored in the UE.

5. The method according to claim 4, wherein, The size of the first RRC message is greater than the maximum size of the Packet Data Convergence Protocol (PDCP) Service Data Unit (SDU).

6. The method according to claim 4, wherein, The at least one segment of the first RRC message includes at least one segment of the RRCReconfiguration message or at least one segment of the RRCResume message.

7. A user equipment (UE) for a communication system, comprising: Transceiver unit; as well as The controller is configured to: Receive UE capability query messages from the base station; Based on the fact that the size of the UE capability information message is greater than the maximum size of the Packet Data Convergence Protocol (PDCP) Service Data Unit (SDU), at least one segment of the UE capability information message is sent to the base station. Receive at least one segment of a first Radio Resource Control (RRC) message from the base station. Store the at least one segment of the received first RRC message. Receive an RRC release message from the base station indicating a transition to an RRC idle state, and Based on the RRC release message indicating a transition to the RRC idle state, at least one segment of the stored first RRC message is discarded.

8. The UE according to claim 7, wherein, The size of the first RRC message is greater than the maximum size of the Packet Data Convergence Protocol (PDCP) Service Data Unit (SDU).

9. The UE according to claim 7, wherein, The at least one segment of the first RRC message includes at least one segment of the RRCReconfiguration message or at least one segment of the RRCResume message.

10. A base station for a communication system, comprising: Transceiver unit; as well as The controller is configured to: Send a UE capability query message to the user equipment (UE); Based on the fact that the size of the UE capability information message is greater than the maximum size of the Packet Data Convergence Protocol (PDCP) Service Data Unit (SDU), at least one segment of the UE capability information message is received from the UE. Generate a Radio Resource Control (RRC) message to be sent to the UE. Generate at least one segment of the first RRC message. Send at least one segment of the first RRC message to the UE. Generate an RRC release message indicating a transition to the RRC idle state, and Send the RRC release message to the UE. The RRC release message is used to instruct the UE to discard at least one segment of the first RRC message stored in the UE.

11. The base station according to claim 10, wherein, The size of the first RRC message is greater than the maximum size of the Packet Data Convergence Protocol (PDCP) Packet Data Unit (SDU).

12. The base station according to claim 10, wherein, The at least one segment of the first RRC message includes at least one segment of the RRCReconfiguration message or at least one segment of the RRCResume message.

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