Method and apparatus for optimizing mt-SDT operation in mobile communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. This method performed by a user equipment (UE) in a wireless communication system may comprise the steps of: receiving, from a base station, a radio resource control (RRC) release message including configuration information on small data transmission (SDT); when a paging message including an SDT indication is received from the base station, performing an RRC resumption procedure for the SDT on the basis of the configuration information; and when the SDT fails, transmitting information indicating a cause of the failure of the SDT to the base station.

Description

Method and device for optimizing MT-SDT operation in a mobile communication system

[0001] The present disclosure relates to a wireless communication system, and more particularly, to a method and apparatus for optimizing MT-SDT (mobile terminated-small data transmission) operation in a mobile communication system.

[0002] 5G mobile communication technology defines a wide frequency band to enable fast transmission speeds and new services, and can be implemented not only in the sub-6GHz frequency band such as 3.5 gigahertz (3.5GHz), but also in the ultra-high frequency band called millimeter wave (mmWave) such as 28GHz and 39GHz ('Above 6GHz'). In addition, for 6G mobile communication technology, which is called the system after 5G communication (Beyond 5G), implementation in the terahertz (THz) band (for example, 3 THz band at 95GHz) is being considered to achieve a transmission speed that is 50 times faster than 5G mobile communication technology and an ultra-low latency time that is reduced to one-tenth.

[0003] In the early stages of 5G mobile communication technology, the goal is to support services and satisfy performance requirements for enhanced Mobile Broadband (eMBB), Ultra-Reliable Low-Latency Communications (URLLC), and massive Machine-Type Communications (mMTC). These include beamforming and massive MIMO to mitigate path loss of radio waves in ultra-high frequency bands and increase the transmission distance of radio waves, support for various numerologies (such as operation of multiple subcarrier intervals) and dynamic operation of slot formats for efficient use of ultra-high frequency resources, initial access technology to support multi-beam transmission and wideband, definition and operation of BWP (Bidth Part), new channel coding methods such as LDPC (Low Density Parity Check) codes for large-capacity data transmission and Polar Code for reliable transmission of control information, and L2 pre-processing (L2). Standardization has been made for network slicing, which provides dedicated networks specialized for specific services, and pre-processing.

[0004] Currently, discussions are underway to improve and enhance the initial 5G mobile communication technology in consideration of the services that 5G mobile communication technology was intended to support, and physical layer standardization is in progress for technologies such as V2X (Vehicle-to-Everything) to help autonomous vehicles make driving decisions and increase user convenience based on their own location and status information transmitted by vehicles, NR-U (New Radio Unlicensed) for the purpose of system operation that complies with various regulatory requirements in unlicensed bands, NR terminal low power consumption technology (UE Power Saving), Non-Terrestrial Network (NTN), which is direct terminal-satellite communication to secure coverage in areas where communication with terrestrial networks is impossible, and Positioning.

[0005] In addition, standardization of wireless interface architecture / protocols is in progress for technologies such as intelligent factories (Industrial Internet of Things, IIoT) to support new services through linkage and convergence with other industries, Integrated Access and Backhaul (IAB) that provides nodes for expanding network service areas by integrating wireless backhaul links and access links, Mobility Enhancement technology including Conditional Handover and Dual Active Protocol Stack (DAPS) handover, and 2-step random access (2-step RACH for NR) that simplifies random access procedures. Standardization is also in progress for system architecture / services such as 5G baseline architecture (e.g., Service-based Architecture, Service-based Interface) for grafting Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC) that provides services based on the location of the terminal.

[0006] Once these 5G mobile communication systems are commercialized, an explosive increase in connected devices will be connected to the communication network, necessitating enhanced functionality and performance of 5G mobile communication systems and integrated operation of these connected devices. To this end, new research will be conducted on improving 5G performance and reducing complexity, supporting AI services, supporting metaverse services, and drone communications by utilizing eXtended Reality (XR), Artificial Intelligence (AI), and Machine Learning (ML) to efficiently support Augmented Reality (AR), Virtual Reality (VR), and Mixed Reality (MR).

[0007] In addition, the development of these 5G mobile communication systems includes new waveforms to ensure coverage in the terahertz band of 6G mobile communication technology, multi-antenna transmission technologies such as Full Dimensional MIMO (FD-MIMO), Array Antenna, and Large Scale Antenna, metamaterial-based lenses and antennas to improve the coverage of terahertz band signals, high-dimensional spatial multiplexing technology using Orbital Angular Momentum (OAM), Reconfigurable Intelligent Surface (RIS) technology, as well as full duplex technology to improve the frequency efficiency and system network of 6G mobile communication technology, satellite, AI (Artificial Intelligence) from the design stage and AI-based communication technology that realizes system optimization by internalizing end-to-end AI support functions, and ultra-high-performance communication and computing resources to provide services with complexity that exceeds the limits of terminal computing capabilities. It can serve as a basis for the development of next-generation distributed computing technologies that can be realized by utilizing them.

[0008] According to one embodiment of the present disclosure, a device and method for effectively providing a service in a mobile communication system are provided.

[0009] According to one embodiment of the present disclosure, a method performed by a user equipment (UE) in a wireless communication system may include the steps of: receiving, from a base station, an RRC (radio resource control) release message including configuration information for small data transmission (SDT); performing an RRC resume procedure for SDT based on the configuration information when a paging message including an SDT indication is received from the base station; and transmitting, when the SDT fails, information indicating a cause of failure of the SDT to the base station.

[0010] According to one embodiment of the present disclosure, a device and method for effectively providing a service in a wireless communication system can be provided.

[0011] The effects that can be obtained from the present disclosure are not limited to the effects mentioned above, and other effects that are not mentioned can be clearly understood by a person having ordinary skill in the art to which the present disclosure belongs from the description below.

[0012] FIG. 1a is a diagram illustrating the structure of a mobile communication system according to one embodiment of the present disclosure.

[0013] FIG. 1b is a diagram for explaining a wireless connection state transition in a mobile communication system according to an embodiment of the present disclosure.

[0014] FIG. 1c is a flowchart of a process for reporting information related to establishment or resume when establishment or resume fails according to one embodiment of the present disclosure.

[0015] FIG. 1d is a flowchart of a process for performing a random access (RA) report according to one embodiment of the present disclosure.

[0016] FIG. 1e is a flowchart of a process for performing an MT-SDT operation according to an embodiment of the present disclosure.

[0017] FIG. 1f is a flowchart of a terminal operation for storing information related to an MT-SDT operation according to an embodiment of the present disclosure.

[0018] FIG. 1g is a flowchart of a base station operation for storing information related to an MT-SDT operation according to an embodiment of the present disclosure.

[0019] FIG. 1h is a block diagram illustrating the internal structure of a terminal according to an embodiment of the present disclosure.

[0020] FIG. 1i is a block diagram showing the configuration of a base station according to one embodiment of the present disclosure.

[0021] In the following description of the present disclosure, detailed descriptions of related known functions or configurations may be omitted if they are deemed to unnecessarily obscure the gist of the present disclosure. Embodiments of the present disclosure are described below with reference to the attached drawings.

[0022] FIG. 1a is a diagram illustrating the structure of a mobile communication system according to one embodiment.

[0023] Referring to FIG. 1a, a wireless access network of a next-generation mobile communication system (New Radio, NR) according to an embodiment may include a next-generation base station (New Radio Node B, hereinafter referred to as gNB) (1a-10) and an access and mobility management function (AMF) (or, AMF entity) (1a-05, New Radio Core Network). A user terminal (New Radio User Equipment, hereinafter referred to as NR UE or terminal) (1a-15) may access an external network through the gNB (1a-10) and the AMF (1a-05).

[0024] In FIG. 1a of the present disclosure, the gNB may correspond to an eNB (Evolved Node B) of an existing LTE (long term evolution) system. For example, the gNB is connected to an NR UE via a wireless channel and may provide a service superior to that of an existing Node B (1a-20). In the next-generation mobile communication system, since all user traffic is serviced through a shared channel, a device that collects status information such as buffer status, available transmission power status, and / or channel status of UEs and performs scheduling may be required, and the operation of collecting status information such as buffer status, available transmission power status, and / or channel status of UEs and performing scheduling may be performed by the gNB (1a-10).

[0025] In one embodiment, a single gNB can typically control multiple cells. To achieve ultra-high-speed data transmission compared to existing LTE, next-generation mobile communication systems can support bandwidths exceeding the existing maximum bandwidth, utilize orthogonal frequency division multiplexing (OFDM) as a wireless access technology, and additionally utilize beamforming technology.

[0026] According to one embodiment, in a next-generation mobile communication system, an adaptive modulation and coding (AMC) method that determines a modulation scheme and a channel coding rate according to the channel condition of a terminal may be applied.

[0027] According to one embodiment, the AMF (1a-05) may perform functions such as mobility support, bearer setup, and / or quality of service (QoS) setup. For example, the AMF may be a device responsible for various control functions as well as mobility management functions for a terminal, and may be connected to multiple base stations.

[0028] According to one embodiment, the next-generation mobile communication system can also be interoperable with the existing long-term evolution (LTE) system, and the AMF (1a-05) can be connected to the LTE mobility management entity (MME) (1a-25) through a network interface. The MME is connected to the existing base station, the eNB (1a-30). A terminal supporting LTE-NR Dual Connectivity (DC) can transmit and / or receive data while maintaining a connection to both the gNB and the eNB (1a-35).

[0029] Figure 1b is a diagram for explaining wireless connection state transition in a next-generation mobile communication system.

[0030] Referring to FIG. 1b, in a next-generation mobile communication system according to an embodiment, a terminal may have three radio resource control (RRC) states. For example, a connected mode (or connected state) (RRC_CONNECTED, 1b-05) may be a radio connection state in which the terminal can transmit and / or receive data. For example, a standby mode (or idle state) (RRC_IDLE, 1b-30) may be a radio connection state in which the terminal monitors whether a paging is transmitted to it. The two modes described above (e.g., connected mode, idle mode) are radio connection states that are also applied to the existing LTE system, and the detailed technology may be substantially the same as that of the existing LTE system. In the next-generation mobile communication system, a newly inactive mode (RRC_INACTIVE) (1b-15) may be defined as one of the radio connection states. For example, in the inactive mode (RRC_INACTIVE) radio connection state, the UE context is maintained between the base station and the terminal, and RAN (radio access network)-based paging can be supported. The characteristics of the new radio connection state are listed below.

[0031] - Cell re-selection mobility;

[0032] - CN (core network) - NR RAN connection (both C / U-planes) has been established for UE;

[0033] - The UE AS(access stratum) context is stored in at least one gNB and the UE;

[0034] - Paging is initiated by NR RAN;

[0035] - RAN-based notification area is managed by NR RAN;

[0036] - NR RAN knows or identify the RAN-based notification area which the UE belongs to;

[0037] According to one embodiment, an INACTIVE radio connection state (e.g., RRC_INACTIVE) can use a designated procedure, and a terminal can transition from the RRC_INACTIVE state to a connected mode or a standby mode. The terminal can transition from INACTIVE mode to a connected mode through a Resume procedure, and the terminal can transition from a connected mode to INACTIVE mode through a Release procedure including suspend configuration information (1b-10). In the procedure described above, one or more RRC messages can be transmitted and / or received between the terminal and the base station, and one or more steps can be configured. In addition, the terminal can transition from INACTIVE mode to a standby mode through a Release procedure after Resume (1b-20). The transition between the connected mode and the standby mode follows the existing LTE technology. That is, transitions between the above-described modes (e.g., RRC_CONENCTED, RRC INACTIVE, RRCE_IDLE) are made through establishment or release procedures (1b-25).

[0038] FIG. 1c is a flowchart of a process for reporting information related to establishment and resume when establishment or resume fails according to one embodiment of the present disclosure.

[0039] Referring to FIG. 1c, a report according to one embodiment may be referred to as a Connection Establishment Failure (CEF) report.

[0040] According to one embodiment, the terminal (1c-00) may trigger a connection request in step 1c-10 (RRSetupRequest or RRCResumeRequest). In this case, the terminal (1c-00) may transmit an RRCSetupRequest message or an RRCResumeRequest message to the base station and may operate the T300, T319, or T319a timer based on whether establishment, resume, or resume with SDT is applied.

[0041] According to one embodiment, if the above-described establishment, resume, or resume with SDT process is not successfully completed until a timer (e.g., T300, T319, or T319a timer) expires, the terminal (1c-00) may consider or identify the establishment, resume, or resume with SDT attempted in step 1c-15 as failed. In this case, the terminal (1c-00) may store certain information in step 1c-20 and report the stored information to the base station for network optimization. (log information related to establishment failure or resume failure)

[0042] According to one embodiment, during the RRC connection establishment or resume process, the terminal (1c-00) may perform a random access process. The terminal may perform the random access process to synchronize uplink with the serving cell and transmit related RRC messages. For example, the random access process may consist of a total of four steps or two steps.

[0043] For example, based on a 4-step random access, in the 1st step, the terminal (1c-00) can transmit a random access preamble to the base station. In the 2nd step, the base station that has received the random access preamble can transmit a random access response message. The random access response message can include information for synchronization, scheduling information to be used by the terminal (1c-00) in the 3rd step, and / or a temporary terminal ID value. In the 3rd step, the terminal transmits a msg 3 message, and the message (e.g., msg 3) can include an RRCResumeRequest if a resume process is performed. In the 4th step, the random access is a contention-based access method, and finally, a message can be transmitted from the base station to the terminal through contention so that the terminal can know that the random access process has been successfully completed. Since the random access process is an important part of the RRC connection establishment or resume process, whether a RACH (random access channel) problem occurs before the T300 timer expires can be useful information for identifying the cause of the failure.

[0044] In one embodiment, after a failure, the terminal (1c-00) can trigger a connection request again in step 1c-25. (connection request)

[0045] According to one embodiment, in step 1c-30, the terminal (1c-00) may transmit an RRCSetupRequest message or an RRCResumeRequest to the base station (1c-05).

[0046] According to one embodiment, in step 1c-35, the base station (1c-05) may transmit an RRCSetup message or RRCResume to the terminal.

[0047] According to one embodiment, in step 1c-40, if the stored Selected PLMN (public land mobile network) value matches its current RPLMN (registered PLMN) and has valid information recorded when an RRC connection establishment or resume failure occurs, the terminal (1c-00) triggers a connEstFailInfoAvailable information element (IE). For example, the triggered IE (Information Element) may be an indicator to notify the base station that the terminal (1c-00) has information (e.g., valid information recorded when an RRC connection establishment or resume failure occurs).

[0048] According to one embodiment, in step 1c-45, the terminal (1c-00) may transmit an RRCSetupComplete message or an RRCResumeComplete message including a connEstFailInfoAvailable IE to the base station (1c-05). If the base station (1c-05) determines that it is necessary to report information (e.g., valid information recorded when an RRC connection establishment or resumption failure occurs), the base station (1c-05) may transmit a UEInformationRequest message including a connEstFail-ReportReq IE to the terminal in step 1c-50.

[0049] For example, the connEstFail-ReportReq IE can be used to request the terminal (1c-00) to report information (e.g., valid information recorded when RRC connection establishment or resumption fails). For example, the connEstFail-ReportReq IE can be included in a UE information request message with the configuration value set to 'True'.

[0050] According to one embodiment, in step 1c-55, if the Selected PLMN value that the terminal (1c-00) is storing matches its current RPLMN, has valid information recorded when RRC connection establishment or resume fails, and the connEstFail-ReportReq IE received from the base station is set to 'True', the terminal (1c-00) can include the recorded information in the connEstFail-Report IE.

[0051] In one embodiment, at step 1c-60, the terminal (1c-00) may transmit a UEInformationResponse message including the connEstFail-Report IE to the base station (1c-05). For example, the reported information may be used by the base station to perform network optimization.

[0052] FIG. 1d is a flowchart of a process for reporting a random access (RA) report according to one embodiment of the present disclosure.

[0053] Referring to Figure 1d, in the next-generation mobile communication system, NR, 2-step RA was introduced in Rel-16, but only 4-step RA-related information can be recorded and reported in the Rel-16 RA Report. However, in the Rel-17 RA Report, not only 4-step RA but also 2-step RA-related information can be recorded and reported.

[0054] According to one embodiment, a terminal (1d-05) may perform a random access procedure for a base station (1d-10) (e.g., a gNB (next generation node B)). For example, the terminal (1d-05) may store certain information related to the most recently successfully performed random access procedure (1d-15). Thereafter, when another random access procedure is performed and successfully completed, the terminal (1d-05) may delete the previously stored information and store certain information related to the new random access procedure.

[0055] All random access processes performed over a recent specified period of time or the last N random access processes may be considered. For example, the terminal (1d-05) may store information about random access processes performed over a recent specified period of time and / or the last N random access processes.

[0056] According to one embodiment, the terminal (1d-05) may store information related to a failed random access process in addition to a successful random access process, depending on the purpose of the random access. For example, information related to a random access process may be stored according to the following ASN (abstract syntax notation).1 structure and reported to the base station (1d-10). For example, one successfully completed random access process may be stored in an RA-Report IE and reported to the base station (1d-10), and up to eight RA reports may be stored or included in an RA-ReportList IE.

[0057] According to one embodiment, a single RA-Report IE may contain or include information about multiple random access attempts in chronological order (Per-RAInfoList IE).

[0058] According to one embodiment, the PerRAInfo IE stored in the Per-RAInfoList may store or include information (e.g., information related to the random access process, information about random access attempts) described above for each synchronization signal block (SSB) or channel state information-reference signal (CSI-RS) used in the random access attempt.

[0059] For example, the PerRAAttemptInfo IE in the PerRAAttemptInfoList may contain information about each random access attempt, contentionDetected and / or dlRSRPAboveThreshold.

[0060] [Table 1] describes the RA-Report. [Table 1] is only an example, and the information included in the RA-Report may include only some of the information in [Table 1], or may include additional information not included in [Table 1].

[0061]

[0062] According to one embodiment, a terminal in standby mode or inactive mode can transmit an RRCSetupRequest or RRCResumeRequest message to a base station to switch to a connected mode (1d-20). The base station (1d-10) can transmit an RRCSetup or RRCResume message to a terminal (1d-05) (1d-25), and the terminal (1d-05) that receives the RRCSetup or RRCResume can switch to a connected mode.

[0063] According to one embodiment, if there is random access-related information stored, the terminal (1d-05) may transmit an RRCSetupComplete or RRCResumeComplete message including an availability indicator indicating that there is random access-related information to the base station (1d-30).

[0064] For example, a base station (1d-10) that has received an indicator (e.g., availability indicator) can request a terminal (1d-05) to report information (e.g., random access related information) using a predetermined RRC message (1d-35).

[0065] According to one embodiment, a terminal (1d-05) that receives a request for a report may transmit a predetermined response RRC message containing stored information (e.g., random access-related information) to the base station (1d-40). For example, RA Report information reported to the base station (1d-10) may be deleted from the terminal (1d-05). For example, even if a stored RA Report is not reported to the base station, the terminal may delete the RA Report after a certain period of time.

[0066] FIG. 1e is a flowchart of a process for performing a mobile-terminated (MT) SDT operation according to one embodiment of the present disclosure.

[0067] Referring to FIG. 1e, SDT (Small Data Transmission) according to one embodiment may be referred to as a technology for transmitting and / or receiving small-sized data during a random access process or using a technology related to Configured Grant (CG) while the terminal (1e-05) is in an inactive mode (RRC_INACTIVE) without switching to a connected mode (RRC_CONNECTED) when the size of data to be transmitted and / or received between a base station (1e-10) and a terminal (1e-05) is small.

[0068] Typically, in order to transmit and / or receive data, a terminal must switch to a connected mode, and for this connection mode switching, certain control messages may need to be exchanged between the base station and the terminal. Furthermore, in order to transmit and / or receive data, the base station (1e-10) may need to schedule the terminal (1e-05). If the size of the data to be transmitted and / or received is not large, performing the operations described above (e.g., control message exchange, scheduling) may be inefficient. To improve this inefficiency, SDT technology may be utilized.

[0069] According to one embodiment, SDT can be divided into MO-SDT (Mobile Originated-Small Data Transmission) and MT-SDT (Mobile Terminated-Small Data Transmission). For example, MO-SDT is a method applied when a terminal (1d-05) transmits data to a base station (1d-10). In other words, MO-SDT is a process applied when transmitting small-sized data in uplink. For example, MT-SDT is a method applied when a base station transmits data to a terminal. In other words, MT-SDT can be applied when transmitting small-sized data in downlink. In addition, for SDT, if random access is utilized, it can be classified as RA-SDT, and if CG is utilized, it can be classified as CG-SDT. For example, in MO-SDT and MT-SDT, whether data is small enough to be transmitted through the MO-SDT or MT-SDT process can be determined based on a value set by the base station. For example, in MT-SDT, the base station (1e-10) can compare the size of the data to be transmitted with a set threshold value, and if it is smaller than the threshold value, it can determine that the data can be transmitted through MT-SDT. For example, in MO-SDT, the base station (1e-10) can set a threshold value to serve as a criterion for determining whether data can be transmitted through MO-SDT to the terminal (1e-05). In this case, the terminal (1e-05) can compare the threshold value with the size of the data that the terminal wants to transmit, and if the size of the data is smaller than the threshold value, it can determine that the data can be transmitted through MO-SDT.

[0070] According to one embodiment, the base station (1e-10) transmits, to the terminal (1e-05), configuration information of a Configured Grant applicable for SDT (e.g., configuration information of CG-SDT) using the RRCRelease message in step 1e-15. For example, the base station (1e-10) may include the CG-SDT configuration information in an RRC message and transmit it to the terminal (1e-05). For example, the SDT-Config IE included in the RRCRelease message may store or include configuration information (e.g., CG-SDT configuration information). (RRCRelease(SDT-Config: cg-SDT-MaxDurationToNext-CG-Occasion))

[0071] According to one embodiment, the configuration information (e.g., CG-SDT configuration information) may include a cg-SDT-MaxDurationToNext-CG-Occasion field. For example, the cg-SDT-MaxDurationToNext-CG-Occasion field may be used by the terminal to determine whether to use RA-SDT or CG-SDT. For example, the cg-SDT-MaxDurationToNext-CG-Occasion field may indicate at least one of RA-SDT or CG-SDT.

[0072] For example, if the time gap until the first CG occasion that arrives after the SDT process is initialized is less than the value indicated by the field (e.g., cg-SDT-MaxDurationToNext-CG-Occasion field), the terminal (1e-05) may select or identify CG-SDT. Otherwise (e.g., if the time gap until the first CG occasion that arrives after the SDT process is initialized is greater than or equal to the value indicated by the field), the terminal (1e-05) may select or identify RA-SDT. This is to prevent data transmission through SDT from being excessively delayed due to the time gap until the first CG occasion that arrives after the SDT process is initialized being too long.

[0073] According to one embodiment, the terminal (1e-05) may transition to an inactive mode after receiving an RRCRelease message in step 1e-20. For example, the terminal (1e-05) may receive an RRC release message from the base station (1e-10), and the state of the terminal (1e-05) may transition to an inactive mode.

[0074] According to one embodiment, the base station (1e-10) may broadcast configuration information of random access applicable for SDT (e.g., configuration information of RA-SDT) to the terminal through SIB1 (system information block 1) in step 1e-25. For example, the configuration information (e.g., configuration information of random access) may include an sdt-RSRP-Threshold field. SIB (mt-SDT-ConfigCommonSIB-r18: sdt-RSRP-Threshold)

[0075] According to one embodiment, the sdt-RSRP-Threshold field may be used to determine whether the terminal uses SDT. For example, if the RSRP (reference signals received power) of the downlink pathloss reference is higher than the value indicated by the sdt-RSRP-Threshold field, the terminal (1e-05) may trigger SDT. For example, if the RSRP of the downlink pathloss reference is less than or equal to the value indicated by the sdt-RSRP-Threshold field, the terminal (1e-05) may not trigger SDT.

[0076] According to one embodiment, the base station (1e-10) may transmit a paging message including an mt-SDT indicator to the terminal (1e-05) at step 1e-30. For example, the mt-SDT indicator may instruct the terminal (1e-05) to perform MT-SDT if a specified condition is satisfied. For example, the specified condition (e.g., a SDT execution condition) may include a condition in which the RSRP value of the received signal is greater than a value indicated by the sdt-RSRP-Threshold field. (Paging (mt-SDT))

[0077] According to one embodiment, a terminal (1e-05) that receives a Paging message including an mt-SDT indicator may determine or identify whether the RSRP of the downlink pathloss reference is higher than a value indicated by a field (e.g., sdt-RSRP-Threshold field) in step 1e-35. For example, the RSRP of the downlink pathloss reference may be the RSRP of a reference signal (e.g., SSB).

[0078] If RSRP is higher than the value indicated by the field, the terminal (1e-05) may trigger SDT. Otherwise (e.g., if RSRP is less than or equal to the value indicated by the field), the terminal (1e-05) may trigger or perform the normal Resume procedure in step 1e-40. In this case, the terminal (1e-05) may transmit an RRCResumeRequest message including a ResumeCause field indicated by mt-Access to the base station (1e-10) in step 1e-45. The terminal (1e-05) may start the T319 timer while transmitting the RRCResumeRequest message to the base station (1e-10). If the Resume procedure is not successfully completed before the T319 timer expires, the terminal (1e-05) may consider or identify that the Resume procedure has failed. In this embodiment, when Resume fails, the terminal (1e-05) stores certain information related to SDT.

[0079] According to one embodiment, if the RSRP of the downlink pathloss reference is higher than the value indicated by the field (e.g., the sdt-RSRP-Threshold field), the terminal (1e-05) may determine or identify whether the time gap until the first CG occasion to arrive is less than the value indicated by the field (e.g., the sdt-RSRP-Threshold field) after initiating the SDT process in step 1e-50. If the time gap until the first occasion is less than the value indicated by the field, the terminal (1e-05) may trigger the CG-SDT in step 1e-55.

[0080] In one embodiment, otherwise (e.g., if the time gap until the first occasion is equal to or greater than the value indicated by the field), the terminal (1e-05) may trigger RA-SDT in step 1e-60.

[0081] According to one embodiment, in the CG-SDT or RA-SDT process (or the process being performed), the terminal (1e-05) may transmit an RRC message (e.g., an RRCResumeRequest message) including a ResumeCause field indicated by mt-SDT in step 1e-65 to the base station (1e-10).

[0082] In one embodiment, determining whether the time gap until the first CG occasion that arrives after the terminal (1e-05) initializes the SDT process is less than the value indicated by the field (e.g., the cg-SDT-MaxDurationToNext-CG-Occasion field) can be understood as determining whether the terminal (1e-05) will perform either CG-SDT or RA-SDT.

[0083] According to one embodiment, the base station (1e-10) that has received a message (e.g., an RRCResumeRequest message) may transmit small-sized user data to the terminal (1e-05) in step 1e-70 (DTCH (Dedicated Traffic Channel)). For example, the size of the user data that can be transmitted to the terminal (1e-05) through the MT-SDT process may be determined based on the implementation or configuration of the base station.

[0084] For example, whether data is small enough to be transmitted through the MO-SDT or MT-SDT process can be determined based on a setting value of the base station (1e-10). For example, in MT-SDT, the base station (1e-10) can compare the size of the data to be transmitted with a set threshold value, and if it is smaller than the threshold value, determine that the data can be transmitted through MT-SDT. For example, in MO-SDT, the base station (1e-10) can set a threshold value to serve as a criterion for determining whether data can be transmitted through MO-SDT to the terminal (1e-05). In this case, the terminal (1e-05) can compare the threshold value with the size of the data that the terminal (1e-05) wants to transmit, and if the size of the data is smaller than the threshold value, determine that the data can be transmitted through MO-SDT.

[0085] According to one embodiment, the terminal (1e-05) starts the T319a timer while transmitting an RRC message (e.g., an RRCResumeRequest message). If at least one of the conditions mentioned below is satisfied, the terminal (1e-05) may consider or identify that the triggered SDT process is not continuing and switch to standby mode. That is, if at least one of the conditions below is satisfied, the terminal (1e-05) may consider or identify that the SDT process has failed.

[0086] - If an indication from the MCG (master cell group) RLC (radio link control) that the maximum number of retransmissions has been reached is received while the SDT procedure is ongoing

[0087] - If a random access problem indication is received from MCG MAC (medium access control) while SDT procedure is ongoing

[0088] - If the lower layers indicate that cg-SDT-TimeAlignmentTimer or the configuredGrantTimer expired before receiving network response for the UL CG-SDT transmission with CCCH message while SDT procedure is ongoing.

[0089] - If an integrity check failure indication is received from lower layers while the SDT procedure is ongoing

[0090] - If T319a expires

[0091] In this embodiment, when SDT fails, the terminal (1e-05) stores certain information related to SDT. The information stored in the terminal (1e-05) can be reported to the base station (1e-10) by the terminal through the UE Information process (e.g., UEInformationRequest message and UEInformationResponse message). The information reported to the base station (1e-10) can be utilized by the network to optimize SDT operation.

[0092] FIG. 1f is a flowchart of a terminal operation for storing information related to an MT-SDT operation according to an embodiment of the present disclosure.

[0093] Referring to FIG. 1f, in step 1f-00, a terminal (e.g., terminal (1e-05) of FIG. 1e) may report its capability information to a base station (e.g., base station (1e-10) of FIG. 1e). For example, the capability information of the terminal may include an indicator indicating whether the terminal supports MT-SDT and an indicator indicating whether the terminal can store SDT-related information and report it to the base station. For example, the capability information of the terminal may include a first indicator indicating whether MT-SDT is supported and / or a second indicator indicating whether SDT-related information can be reported.

[0094] According to one embodiment, in step 1f-05, the terminal may receive an RRC message (e.g., an RRCRelease message) from the base station containing configuration information related to CG-SDT. For example, the configuration information related to CG-SDT may include a cg-SDT-MaxDurationToNext-CG-Occasion field.

[0095] According to one embodiment, in step 1f-10, the terminal may receive system information (e.g., SIB1) containing configuration information related to RA-SDT broadcast from the base station. For example, the configuration information may include the sdt-RSRP-Threshold field. (receives SIB1 with mt-SDT-ConfigcommonSIB)

[0096] According to one embodiment, in step 1f-15, the terminal may receive a Paging message including an mt-SDT indicator from the base station.

[0097] In one embodiment, in step 1f-20, the terminal may determine or identify whether the RSRP of the downlink pathloss reference is higher than a value indicated by a field (e.g., sdt-RSRP-Threshold field). For example, the RSRP of the downlink pathloss reference may be the RSRP of a reference signal (e.g., SSB).

[0098] According to one embodiment, in step 1f-25, if the RSRP of the downlink pathloss reference is not higher than the value indicated by the field, the terminal must transition to connected mode to receive user data, and may trigger a Resume process for the connected mode transition. In this case, the terminal may set the ResumeCause field included in the RRCResumeRequest to mt-Access.

[0099] According to one embodiment, in step 1f-30, if the Resume process is deemed to have failed based on a predetermined condition, the terminal may store the following SDT-related information. For example, the SDT-related information may be stored as CEF Report content.

[0100] - An indication to indicate that the paging message includes an mt-SDT indication, but the DL RSRP is not higher than the sdt-RSRP-Threshold. For example, the SDT-related information may indicate that a condition related to the sdt-RSRP-Threshold (e.g., DL RSRP is greater than the sdt-RSRP-Threshold) was not satisfied, and thus the general Resume procedure corresponding to the ResumeCause value of mt-Access was triggered. That is, the indication that the paging message includes an mt-SDT indication, but the DL RSRP is not higher than the sdt-RSRP-Threshold, can be used to distinguish between SDT failure and Resume failure.

[0101] - Configured value of sdt-RSRP-Threshold

[0102] According to one embodiment, in step 1f-35, if the RSRP of the downlink pathloss reference is higher than the value indicated by the field (e.g., Sdt-RSRP-Threshold), the terminal can determine or identify whether the time gap until the first CG occasion to arrive is less than the value indicated by the field after initiating the CG-SDT transmission. For example, the initiation of the CG-SDT transmission can be referenced by receiving a Paging message including an mt-SDT indicator, or when all CG-SDT trigger conditions are satisfied.

[0103] According to one embodiment, in step 1f-40, after the terminal initializes the SDT process, it may trigger CG-SDT if the time gap until the first CG occasion to arrive is less than the value indicated by the field (e.g., cg-SDT-MaxDurationToNext-CG-Occasion field).

[0104] According to one embodiment, in step 1f-45, if the terminal determines or identifies that the CG-SDT or the Resume process corresponding to the CG-SDT has failed based on certain conditions, the terminal may store the following SDT-related information. For example, the following information may be stored as CEF Report content.

[0105] - Indication to indicate that CG-SDT has been initiated for MT-SDT, and at least one SSB configured for CG-SDT with SS-RSRP above cg-SDT-RSRP-ThresholdSSB is not available. For example, the indication is intended to indicate (beam) failure of CG-SDT triggered for MT-SDT.

[0106] - Configured value of sdt-RSRP-Threshold

[0107] - Configured value of cg-SDT-MaxDurationToNextCG-Occasion

[0108] - Configured value of cg-SDT-RSRP-ThresholdSSB

[0109] - Selected SSB for CG-SDT

[0110] - Time between the initiation of the CG-SDT transmission and the first available CG occasion for initial CG-SDT transmission

[0111] - Time between the reception of paging and the transmission of RRCResumeRequest

[0112] - Time between the reception of paging and considering or identifying the configured uplink grant as not valid

[0113] - SDT failure cause information. That is, at least one of the following causes can be stored. For example, information (e.g., SDT failure cause information) can be indicated in the ENUMERATED format in ASN.1.

[0114] ■ Indication to indicate if indication from the MCG RLC that the maximum number of retransmissions has been reached is received while SDT procedure is ongoing

[0115] ■ Indication to indicate if random access problem indication is received from MCG MAC while SDT procedure is ongoing

[0116] ■ Indication to indicate if the lower layers indicate that cg-SDT-TimeAlignmentTimer or the configuredGrantTimer expired before receiving network response for the UL CG-SDT transmission with CCCH message while SDT procedure is ongoing

[0117] ■ Indication to indicate if integrity check failure indication is received from lower layers while SDT procedure is ongoing

[0118] ■ Indication to indicate if T319a expires

[0119] Due to the various causes described above, a terminal may consider the SDT being performed as failed. At this time, the terminal can record (or identify) the cause of the SDT failure and report the cause of the failure to the base station later. However, to indicate all the various causes, the number of bits in the field used to indicate the various causes increases. This means increased signaling overhead. On the other hand, among the causes causing SDT failure, certain causes have a very low probability of occurrence or can be easily inferred by the base station through other related information. Reporting these types of causes (e.g., failure causes with a low probability of occurrence or inferred through other information) to the base station by the terminal increases signaling overhead and may reduce its usefulness. In the present disclosure, we propose to indicate other causes, except for certain important SDT failure causes that must be indicated through the terminal's report, using a single code point. For example, if SDT failure due to T319a expiration is a critical cause and the remaining causes are non-critical causes, the field used to indicate SDT failure can be defined as follows.

[0120]

[0121] At this time, if T319a expiration is the cause of SDT failure, the "t319a-Expiry" value is set, and if there are other causes, the "other" value is set. Since multiple causes can correspond to the "other" value, a base station that receives a field set to the "other" value may need to implementally identify the cause of failure through other information. If other important causes other than T319a expiration need to be separately indicated, a new code point corresponding to this must be added to the information field below.

[0122] However, the fact that multiple causes correspond to other is only an example, and that only one cause corresponds to other.

[0123] According to one embodiment, in step 1f-50, after the terminal initializes the SDT process, it may trigger RA-SDT if the time gap until the first CG occasion to arrive is not less than the value indicated by the field (e.g., cg-SDT-MaxDurationToNext-CG-Occasion field).

[0124] According to one embodiment, in step 1f-55, if the terminal determines or identifies that the RA-SDT or the Resume process corresponding to the RA-SDT has failed based on a predetermined condition, the terminal may store the following SDT-related information. For example, the information below may be stored as CEF Report content or RA Report content.

[0125] - Configured value of sdt-RSRP-Threshold

[0126] - Configured value of cg-SDT-MaxDurationToNextCG-Occasion

[0127] - Configured value of cg-SDT-RSRP-ThresholdSSB

[0128] - Selected SSB for CG-SDT

[0129] - Time between the initiation of the CG-SDT transmission and first available CG occasion for initial CG-SDT transmission

[0130] - Time between the reception of Paging and the transmission RRRCesumeRequest

[0131] - Time between the reception of Paging and considering the configured uplink grant as not valid

[0132] - SDT failure cause information. That is, at least one of the following causes can be stored. For example, information (e.g., SDT failure cause information) can be indicated in the ENUMERATED format in ASN.1.

[0133] ■ Indication to indicate if indication from the MCG RLC that the maximum number of retransmissions has been reached is received while SDT procedure is ongoing

[0134] ■ Indication to indicate if random access problem indication is received from MCG MAC while SDT procedure is ongoing

[0135] ■ Indication to indicate if the lower layers indicate that cg-SDT-TimeAlignmentTimer or the configuredGrantTimer expired before receiving network response for the UL CG-SDT transmission with CCCH message while SDT procedure is ongoing

[0136] ■ Indication to indicate if integrity check failure indication is received from lower layers while SDT procedure is ongoing

[0137] ■ Indication to indicate if T319a expires

[0138] - Indicator indicating whether the RA-SDT procedure is successful or not. The indicator indicating whether the RA-SDT procedure is successful or not can be indicated according to the following options (e.g., option 1 to option 3).

[0139] ● Option 1: Explicitly indicate MO-SDT and MT-SDT failures in ENUMERATED format

[0140] ● Considering Rel-18 MT-SDT together, it explicitly indicates either MO-SDT failure or MT-SDT

[0141] ● sdtFailureType-r18 ENUMERATED {mo-SdtFailure, mt-SdtFailure, spare2, spare1}

[0142] ● Option 2: Indicate SDT failure regardless of MO-SDT or MT-SDT. Whether it is an MT-SDT failure or not can be recognized or identified by the MT-SDT-related information proposed in this embodiment. In addition, while dedicated RACH radio resources can be used in MO-SDT, since dedicated RACH radio resources are not allocated separately in MT-SDT, the network can determine or identify whether it is MO-SDT or MT-SDT through the information on the used RACH radio resources stored in the RA Report.

[0143] ● It just indicates SDT failure, regardless of SDT types

[0144] ● sdtFailure-r18 ENUMERATED {true}

[0145] ● MT-SDT would be implicitly distinguished from MO-SDT, with any new information related to MT-SDT failure

[0146] ● Option 3: MO-SDT and MT-SDT failures are explicitly indicated by separate corresponding fields.

[0147] ● Just separate indications

[0148] ● mo-SdtFailure-r18 ENUMERATED {true}

[0149] ● mt-SdtFailure-r18 ENUMERATED {true}

[0150] According to one embodiment, when information on a random access performed when an RA-SDT trigger condition is satisfied is stored in an RA Report, the raPurpose field, which is one of the RA Report contents, may indicate that the random access was performed by RA-SDT. For example, the following code point may be newly defined.

[0151] Option 1: Define a new code point indicating that the random access corresponding to the RA Report corresponds to the RA-SDT (e.g., [Table 3]). See the ASN.1 example below.

[0152]

[0153] ● Option 2: Define multiple new code points (e.g., [Table 4]) that indicate that random access corresponding to the RA Report corresponds to the MO-SDT or MT-SDT of the RA-SDT. See the ASN.1 example below.

[0154]

[0155] ● Option 3: Random accesses corresponding to RA Reports are always indicated by the existing code point accessRelated. Whether the random access corresponds to RA-SDT or MO- / MT-SDT can be indicated by a separate field.

[0156] According to one embodiment, at least some of the SDT-related information that can be stored by a terminal that has performed an SDT procedure may be stored even when the performed SDT procedure is successfully completed. For example, even when the SDT procedure is successfully completed, the SDT-related information may include at least one of a Configured value of sdt-RSRP-Threshold, a Configured value of cg-SDT-MaxDurationToNextCG-Occasion, a Configured value of cg-SDT-RSRP-ThresholdSSB, a Selected SSB for CG-SDT, a Time between the initiation of the CG-SDT transmission and the first available CG occasion for initial CG-SDT transmission, a Time between the reception of Paging and the transmission RRCResumeRequest, a Time between the reception of Paging and considering the configured uplink grant as not valid, SDT failure cause information, or an indicator indicating whether the RA-SDT procedure was successful.

[0157] FIG. 1g is a flowchart of a base station operation for storing information related to an MT-SDT operation according to an embodiment of the present disclosure.

[0158] Referring to FIG. 1g, in step 1g-05, a base station (e.g., base station (1e-10) of FIG. 1e) may receive capability information of a terminal (e.g., terminal (1e-05) of FIG. 1e). For example, the capability information may include an indicator indicating whether the terminal supports MT-SDT and an indicator indicating whether the terminal can store SDT-related information and report it to the base station. For example, the capability information of the terminal may include a first indicator indicating whether MT-SDT is supported and / or a second indicator indicating whether SDT-related information can be reported.

[0159] In one embodiment, in step 1g-10, the base station may transmit an RRC message (e.g., an RRCRelease message) containing configuration information related to CG-SDT to the terminal. For example, the configuration information related to CG-SDT may include the cg-SDT-MaxDurationToNext-CG-Occasion field.

[0160] In one embodiment, in step 1g-15, the base station may broadcast system information (e.g., SIB1) containing configuration information related to RA-SDT. For example, the configuration information related to RA-SDT may include the sdt-RSRP-Threshold field. (broadcast SIB1 with mt-SDT-ConfigCommonSIB)

[0161] According to one embodiment, in step 1g-20, the base station may transmit a Paging message including an mt-SDT indicator to the terminal.

[0162] In one embodiment, at step 1g-25, the base station may receive from the terminal a predetermined RRC message including an indicator indicating that the terminal itself is storing the CEF Report and / or RA Report content.

[0163] In one embodiment, at step 1g-30, the base station may transmit a UEInformationRequest message requesting the terminal to report information stored by the terminal (e.g., CEF report, RA report contents).

[0164] According to one embodiment, in step 1g-35, the base station can receive a CEF Report or RA Report including information related to SDT from the terminal.

[0165] In one embodiment, in step 1g-40, the base station may forward the received information (e.g., information related to SDT) to the base station or network entity related to the information, or the base station itself may utilize the received information to optimize the SDT operation. For example, the base station may utilize the received information (e.g., information related to SDT) to adjust the SDT trigger frequency or adjust the sdt-RSRP-Threshold or cg-SDT-MaxDurationToNext-CG-Occasion values ​​related to the SDT trigger condition to reduce the delay time of data transmission through SDT.

[0166] Figure 1h is a block diagram showing the internal structure of a terminal to which the present disclosure is applied.

[0167] Referring to FIG. 1h, a terminal (e.g., terminal (1e-05) of FIG. 1e) includes a radio frequency (RF) processing unit (1h-10), a baseband processing unit (1h-20), a storage unit (1h-30), and a control unit (1h-40). As another example, the terminal may include a transceiver and / or a controller. In this case, the transceiver may be configured to include an RF processing unit (1h-10) and a baseband processing unit (1h-20). The terminal of FIG. 1h of the present disclosure may correspond to the terminals of FIGS. 1a to 1g.

[0168] According to one embodiment, the RF processing unit (1h-10) may perform functions for transmitting and / or receiving signals through a wireless channel, such as signal band conversion and amplification. For example, the RF processing unit (1h-10) may up-convert a baseband signal provided from the baseband processing unit (1h-20) into an RF band signal and then transmit the same through an antenna, and down-convert an RF band signal received through the antenna into a baseband signal.

[0169] For example, the RF processing unit (1h-10) may include a transmitting filter, a receiving filter, an amplifier, a mixer, an oscillator, a digital to analog convertor (DAC), and / or an analog to digital convertor (ADC). Although only one antenna is illustrated in FIG. 1h of the present disclosure, the terminal may include multiple antennas. In addition, the RF processing unit (1h-10) may include multiple RF chains. Furthermore, the RF processing unit (1h-10) may perform beamforming. For beamforming, the RF processing unit (1h-10) may adjust the phase and magnitude of each signal transmitted and / or received through multiple antennas or antenna elements (e.g., phase shifters). In addition, the RF processing unit (1h-1) may perform MIMO (multi-input multi-output) and may receive multiple layers when performing the MIMO operation.

[0170] According to one embodiment, the baseband processing unit (1h-20) may perform a conversion function between a baseband signal and a bit stream according to the physical layer specifications of the system. For example, when transmitting data, the baseband processing unit (1h-20) generates complex symbols by encoding and modulating a transmission bit stream. In addition, when receiving data, the baseband processing unit (1h-20) may restore a reception bit stream by demodulating and decoding a baseband signal provided from the RF processing unit (1h-10). For example, in the case of an orthogonal frequency division multiplexing (OFDM) scheme, when transmitting data, the baseband processing unit (1h-20) may generate complex symbols by encoding and modulating a transmission bit stream, map the complex symbols to subcarriers, and then configure OFDM symbols by performing an inverse fast Fourier transform (IFFT) operation and inserting a cyclic prefix (CP). In addition, when receiving data, the baseband processing unit (1h-20) divides the baseband signal provided from the RF processing unit (1h-10) into OFDM symbol units, restores signals mapped to subcarriers through an FFT (fast Fourier transform) operation, and then restores the received bit string through demodulation and decoding.

[0171] According to one embodiment, the baseband processing unit (1h-20) and the RF processing unit (1h-10) may transmit and receive signals as described above. Accordingly, the baseband processing unit (1h-20) and the RF processing unit (1h-10) may be referred to as a transmitter, a receiver, a transceiver, or a communication unit. Furthermore, at least one of the baseband processing unit (1h-20) and the RF processing unit (1h-10) may include a plurality of communication modules to support a plurality of different wireless access technologies. In addition, at least one of the baseband processing unit (1h-20) and the RF processing unit (1h-10) may include different communication modules to process signals of different frequency bands. For example, the different wireless access technologies may include wireless LAN (e.g., IEEE 802.11) and / or a cellular network (e.g., LTE). Additionally, the different frequency bands may include a super high frequency (SHF) (e.g., 2.NRHz, NRhz) band, and / or a millimeter wave (mm wave) (e.g., 60GHz) band.

[0172] According to one embodiment, the storage unit (1h-30) can store data such as basic programs, application programs, and setting information for the operation of the terminal. In particular, the storage unit (1h-30) can store information related to a second access node that performs wireless communication using a second wireless access technology. In addition, the storage unit (1h-30) can provide the stored data upon request from the control unit (1h-40).

[0173] According to one embodiment, the control unit (1h-40) can control the overall operations of the terminal. For example, the control unit (1h-40) can transmit and / or receive signals through the baseband processing unit (1h-20) and the RF processing unit (1h-10). In addition, the control unit (1h-40) can record and read data in the storage unit (1h-40). For this purpose, the control unit (1h-40) can include at least one processor. For example, the control unit (1h-40) can include a communication processor (CP) that performs control for communication and an application processor (AP) that controls upper layers such as application programs.

[0174] FIG. 1i is a block diagram showing the configuration of a base station according to one embodiment.

[0175] Referring to FIG. 1i, a base station (e.g., a base station (1e-10) of FIG. 1e) may include an RF processing unit (1i-10), a baseband processing unit (1i-20), a backhaul communication unit (1i-30), a storage unit (1i-40), and / or a control unit (1i-50). As another example, the base station may include a transceiver and / or a controller. In this case, the transceiver may be configured to include an RF processing unit (1i-10) and a baseband processing unit (1i-20). The base station of FIG. 1i of the present disclosure may correspond to the base stations of FIGS. 1a to 1g.

[0176] According to one embodiment, the RF processing unit (1i-10) may perform functions for transmitting and / or receiving signals through a wireless channel, such as signal band conversion and amplification. For example, the RF processing unit (1i-10) may up-convert a baseband signal provided from the baseband processing unit (1i-20) into an RF band signal and transmit the up-converted signal through an antenna, and may down-convert an RF band signal received through the antenna into a baseband signal.

[0177] For example, the RF processing unit (1i-10) may include a transmitting filter, a receiving filter, an amplifier, a mixer, an oscillator, a DAC, and / or an ADC, etc. In FIG. 1i of the present disclosure, only one antenna is illustrated, but the first access node may include multiple antennas. In addition, the RF processing unit (1i-10) may include multiple RF chains. Furthermore, the RF processing unit (1i-10) may perform beamforming. For beamforming, the RF processing unit (1i-10) may adjust the phase and magnitude of each signal transmitted and / or received through the multiple antennas or antenna elements. The RF processing unit (1i-10) may perform a downlink MIMO operation by transmitting one or more layers.

[0178] According to one embodiment, the baseband processing unit (1i-20) may perform a conversion function between a baseband signal and a bit stream according to the physical layer specification of the first wireless access technology. For example, when transmitting data, the baseband processing unit (1i-20) may generate complex symbols by encoding and modulating a transmission bit stream. In addition, when receiving data, the baseband processing unit (1i-20) may restore a reception bit stream by demodulating and decoding a baseband signal provided from the RF processing unit (1i-10). For example, in the case of OFDM, when transmitting data, the baseband processing unit (1i-20) may generate complex symbols by encoding and modulating a transmission bit stream, map the complex symbols to subcarriers, and then configure OFDM symbols through an IFFT operation and CP insertion. In addition, when receiving data, the baseband processing unit (1i-20) can divide the baseband signal provided from the RF processing unit (1i-10) into OFDM symbol units, restore the signals mapped to subcarriers through FFT operation, and then restore the received bit string through demodulation and decoding. The baseband processing unit (1i-20) and the RF processing unit (1i-10) can transmit and / or receive signals as described above. Accordingly, the baseband processing unit (1i-20) and the RF processing unit (1i-10) may be referred to as a transmitter, a receiver, a transceiver, a communication unit, or a wireless communication unit.

[0179] According to one embodiment, the backhaul communication unit (1i-30) may provide an interface for performing communication with other nodes within the network. For example, the backhaul communication unit (1i-30) may convert a bit string transmitted from the main base station to another node, such as an auxiliary base station or a core network, into a physical signal, and may convert a physical signal received from the other node into a bit string.

[0180] According to one embodiment, the storage unit (1i-40) can store data such as basic programs, application programs, and setting information for the operation of the main base station. In particular, the storage unit (1i-40) can store information on bearers assigned to connected terminals and / or measurement results reported from connected terminals. For example, the storage unit (1i-40) can store information that serves as a criterion for determining whether to provide or terminate multiple connections to a terminal. For example, the storage unit (1i-40) can provide stored data at the request of the control unit (1i-50).

[0181] According to one embodiment, the control unit (1i-50) can control the overall operations of the base station. For example, the control unit (1i-50) can transmit and / or receive signals through the baseband processing unit (1i-20) and the RF processing unit (1i-10) or through the backhaul communication unit (1i-30). In addition, the control unit (1i-50) records and reads data in the storage unit (1i-40). For this purpose, the control unit (1i-50) can include at least one processor.

[0182] The methods according to the embodiments described in the claims or specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0183] When implemented in software, a computer-readable storage medium storing one or more programs (software modules) may be provided. The one or more programs stored in the computer-readable storage medium are configured for execution by one or more processors within an electronic device. The one or more programs include instructions that cause the electronic device to execute methods according to the embodiments described in the claims or specification of the present disclosure.

[0184] These programs (software modules, software) may be stored in a non-volatile memory including random access memory, flash memory, read only memory (ROM), electrically erasable programmable read only memory (EEPROM), magnetic disc storage devices, compact disc ROMs (CD-ROMs), digital versatile discs (DVDs) or other forms of optical storage devices, magnetic cassettes, or may be stored in a memory configured as a combination of some or all of these. In addition, each configuration memory may be included in multiple numbers.

[0185] Additionally, the program may be stored on an attachable storage device that is accessible via a communication network such as the Internet, an intranet, a local area network (LAN), a wide local area network (WLAN), a storage area network (SAN), or a combination thereof. Such a storage device may be connected to a device implementing an embodiment of the present disclosure via an external port. Additionally, a separate storage device on the communication network may be connected to a device implementing an embodiment of the present disclosure.

[0186] In the specific embodiments of the present disclosure described above, components included in the present disclosure are expressed singularly or plurally, depending on the specific embodiment presented. However, the singular or plural expressions are selected to suit the presented situation for convenience of explanation, and the present disclosure is not limited to singular or plural components. Components expressed in plural may be composed of singular elements, or components expressed in singular may be composed of plural elements.

[0187] Meanwhile, the embodiments of the present disclosure disclosed in this specification and drawings are merely specific examples to easily explain the technical contents of the present disclosure and to help understand the present disclosure, and are not intended to limit the scope of the present disclosure. In other words, it will be apparent to those skilled in the art that other modifications based on the technical idea of ​​the present disclosure are possible. In addition, the respective embodiments may be combined and operated with each other as needed. For example, parts of one embodiment of the present disclosure and another embodiment may be combined with each other to operate a base station and a terminal. In addition, the embodiments of the present disclosure are applicable to other communication systems, and other modifications based on the technical idea of ​​the embodiments may also be implemented.

Claims

1. A method performed by a UE (user equipment) in a wireless communication system, A step of receiving an RRC (radio resource control) release message including configuration information for SDT (small data transmission) from a base station; When receiving a paging message including an SDT indication from the base station, a step of performing an RRC resume procedure for SDT based on the configuration information; and A method comprising the step of transmitting information indicating the cause of failure of the SDT to the base station when the SDT fails.

2. In claim 1, A method wherein the cause of failure of the SDT comprises expiration of a timer associated with the failure of the SDT.

3. In claim 1, Further comprising a step of receiving SIB 1 (system information block 1) from the above base station, The above SIB 1 includes first information about a threshold value for determining whether a mobile terminated (MT) SDT can be started, A method wherein the above configuration information includes second information about a maximum period until the next CG (configured grant)-SDT occasion.

4. In claim 3, A method, wherein, if the RSRP (reference signal received power) of the DL (downlink) pathloss reference is higher than a value set based on the first information, and the period between the start of the SDT and the next CG-SDT occasion is less than the maximum period set based on the second information, the SDT is performed according to the CG-SDT.

5. A method performed by a base station in a wireless communication system, A step of transmitting an RRC (radio resource control) release message including configuration information for SDT (small data transmission) to a UE (user equipment); A step of transmitting a paging message including an SDT indication to the UE; and A method comprising the step of receiving information indicating a cause of failure of the SDT from the UE when the SDT based on the above setting information fails.

6. In claim 5, A method wherein the cause of failure of the SDT comprises expiration of a timer associated with the failure of the SDT.

7. In claim 5, Further comprising a step of transmitting SIB 1 (system information block 1) to the UE, The above SIB 1 contains first information about a threshold value associated with whether a mobile terminated (MT) SDT can be started, A method wherein the above configuration information includes second information about a maximum period until the next CG (configured grant)-SDT occasion.

8. In claim 7, A method, wherein, if the RSRP (reference signal received power) of the DL (downlink) pathloss reference is higher than a value set based on the first information, and the period between the start of the SDT and the next CG-SDT occasion is less than the maximum period set based on the second information, the SDT is performed according to the CG-SDT.

9. In a wireless communication system, in the UE (user equipment), transceiver; and A controller coupled with the above transceiver, The above controller: Receive an RRC (radio resource control) release message containing configuration information for SDT (small data transmission) from a base station, When receiving a paging message including an SDT indication from the above base station, perform an RRC resume procedure for SDT based on the above configuration information, A UE configured to transmit information indicating the cause of failure of the SDT to the base station when the above SDT fails.

10. In claim 9, The above failure cause of the above SDT includes expiration of a timer associated with the failure of the above SDT, UE.

11. In claim 9, The above controller: It is set to receive SIB 1 (system information block 1) from the above base station, The above SIB 1 includes first information about a threshold value for determining whether a mobile terminated (MT) SDT can be started, The above configuration information includes second information about the maximum period until the next CG (configured grant)-SDT occasion.

12. In claim 11, A UE, wherein if the RSRP (reference signal received power) of the DL (downlink) pathloss reference is higher than a value set based on the first information, and the period between the start of the SDT and the next CG-SDT occasion is less than the maximum period set based on the second information, the SDT is performed according to the CG-SDT.

13. In a base station in a wireless communication system, transceiver; and A controller coupled with the above transceiver, The above controller: Transmit an RRC (radio resource control) release message containing configuration information for SDT (small data transmission) to the UE (user equipment), Transmitting a paging message including an SDT indication to the UE, A base station configured to receive information indicating a cause of failure of the SDT from the UE when the SDT based on the above setting information fails.

14. In claim 13, A base station, wherein the cause of failure of the above SDT includes expiration of a timer associated with the failure of the above SDT.

15. In claim 13, Further comprising a step of transmitting SIB 1 (system information block 1) to the UE, The above SIB 1 contains first information about a threshold value associated with whether a mobile terminated (MT) SDT can be started, The above configuration information includes second information about the maximum period until the next CG (configured grant)-SDT occasion, A base station, wherein, if the RSRP (reference signal received power) of the DL (downlink) pathloss reference is higher than a value set based on the first information, and the period between the start of the SDT and the next CG-SDT occasion is less than the maximum period set based on the second information, the SDT is performed according to the CG-SDT.

Images