Method and apparatus for transmitting small data.

Abstract

The present disclosure provides a communication method and system that uses Internet of Things (IoT) technology to integrate a fifth generation (5G) communication system that supports a higher data transmission rate than a fourth generation (4G) system. The present disclosure can be applied to intelligent services based on 5G communication technology and IoT-related technologies, such as smart homes, smart buildings, smart cities, smart cars, connected cars, healthcare, digital education, smart retail, security and safety services. A method and device for transmitting small data are provided.

Description

[Technical Field]

[0001] This disclosure relates to wireless communication systems. More specifically, this disclosure relates to devices, methods, and systems for transmitting small data in wireless communication systems. [Background technology]

[0002] To meet the increasing demand for wireless data traffic since the commercialization of 4G communication systems, efforts are being made to develop improved 5G or pre-5G communication systems. For this reason, 5G or pre-5G communication systems are also called "Beyond 4G Network" communication systems or "Post LTE System" communication systems. To achieve a high data transmission rate, 5G communication systems are expected to be implemented in the ultra-high frequency (mmWave) band (e.g., the 60GHz band). To reduce radio wave propagation loss and increase transmission distance, beamforming, massive MIMO (Multiple-Input Multiple-Output), FD-MIMO (Full Dimensional MIMO), array antennas, analog beamforming, and large-scale antenna technologies are being discussed for 5G communication systems. Furthermore, in order to improve the system's network, 5G communication systems are undergoing technological development, including advanced small cells, cloud radio access networks (cloud RANs), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, moving networks, cooperative communication, CoMP (Coordinated Multi-Point), and reception-end interference cancellation.5G communication systems have seen the development of advanced coding modulation (ACM) methods such as FQAM (Hybrid FSK and QAM Modulation) and SWSC (Sliding Window Superposition Coding), as well as advanced access technologies such as FBMC (Filter Bank Multi Carrier), NOMA (non-orthogonal multiple access), and SCMA (sparse code multiple access).

[0003] The internet, a human-centered connection network where humans generate and consume information, is evolving into the Internet of Things (IoT), where distributed entities like objects exchange and process information without human intervention. Internet of Everything (IoE) technology, which combines IoT technology via cloud server connectivity with big data processing technology, is on the rise. To realize IoT, technological elements such as sensing technology, wired and wireless communication and network infrastructure, service interface technology, and security technology are required. Recently, technologies such as sensor networks, M2M (Machine-to-Machine), and MTC (Machine-type Communication) for connecting objects are being researched. In an IoT environment, intelligent IT (Internet Technology) services can be provided that collect and analyze data generated by connected objects, creating new value for human life. IoT can be applied to fields such as smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, healthcare, smart home appliances, and advanced medical services through the integration and combination of existing IT (Information Technology) technologies and various industries.

[0004] Accordingly, various attempts are being made to apply 5G communication systems to IoT networks. For example, technologies such as sensor networks, MTC (Machine-Type Communication), and M2M (Machine-to-Machine) are realized through 5G communication technology using techniques such as beamforming, MIMO, and array antennas. The application of cloud RAN (cloud Radio Access Network) as a big data processing technology, as mentioned earlier, can also be said to be an example of the convergence between 5G technology and IoT technology.

[0005] Meanwhile, various studies have recently been conducted on small data transmission (SDT) in 5G communication systems.

[0006] The information described above is provided solely as background information to facilitate understanding of this disclosure. No determination has been made, nor has any claim been made, regarding whether any of the information described above can be applied as prior art in relation to this disclosure. [Overview of the project] [Problems that the invention aims to solve]

[0007] The SDT procedures for wireless communication systems need to be improved. [Means for solving the problem]

[0008] Aspects of this disclosure will at least resolve the problems and / or disadvantages described above and provide at least the advantages described below. Accordingly, one aspect of this disclosure provides a communication method and system that integrates fourth-generation (5G) communication systems that support even higher data transmission rates than fourth-generation (4G) systems.

[0009] Additional aspects are described in part in the following description, may become apparent from the description, or can be learned by performing the presented embodiments.

[0010] A part of the present disclosure provides a method performed by a terminal. The method includes: receiving a radio resource control (RRC) deactivation message from a base station including at least one configured grant uplink resource for small data transmission (SDT); identifying an uplink carrier from among a normal uplink (NUL) or a supplementary uplink (SUL) based on an SDT procedure initiated while the terminal is in an RRC deactivation state; identifying an SSB from among synchronization signal blocks (SSBs) associated with a configured grant uplink resource for the SDT procedure on the identified uplink carrier; and transmitting uplink data to the base station on the uplink grant corresponding to the identified SSB.

[0011] Other aspects of the present disclosure provide a method performed by a base station. The method includes the steps of: sending a Radio Resource Control (RRC) deactivation message to a terminal including at least one configured grant uplink resource for small data transmission (SDT); and receiving uplink data from the terminal on an uplink grant corresponding to a synchronized signal block (SSB) - the SSB is one of a plurality of SSBs associated with the configured grant uplink resource for the SDT procedure on an uplink carrier, and the uplink carrier is one of a general uplink (NUL) or a supplementary uplink (SUL) - based on an SDT procedure initiated while the RRC is deactivated.

[0012] In other aspects of the present disclosure, a terminal is provided. The terminal includes a transceiver and at least one processor, the at least one processor which receives a Radio Resource Control (RRC) deactivation message from a base station via the transceiver, including at least one configured grant uplink resource for small data transmission (SDT), identifies an uplink carrier from among a general uplink (NUL) or supplementary uplink (SUL) based on an SDT procedure initiated while the terminal is in an RRC deactivation state, identifies a synchronization signal block (SSB) from among SSBs associated with the configured grant uplink resource for the SDT procedure on the identified uplink carrier, and is configured to transmit uplink data to the base station via the transceiver on the uplink grant corresponding to the identified SSB.

[0013] According to other aspects of the present disclosure, a base station is provided. The base station includes a transceiver and at least one processor, the at least one processor being configured to receive from the terminal via the transceiver uplink data on an uplink grant corresponding to a synchronized signal block (SSB) - the SSB is one of a plurality of SSBs associated with a grant uplink resource configured for the SDT procedure on an uplink carrier, and the uplink carrier is one of a general uplink (NUL) or a supplementary uplink (SUL) - based on an SDT procedure initiated while the terminal is in an RRC deactivated state.

[0014] Other aspects, advantages, and notable features of this disclosure will be apparent to those skilled in the art from the following detailed description, which is taken together with the accompanying drawings and which discloses various embodiments of this disclosure. [Effects of the Invention]

[0015] According to the various embodiments of this disclosure, SDT procedures can be efficiently improved.

[0016] The above-described other aspects, features, and advantages of specific embodiments of the present disclosure will become even more apparent from the following description taken in conjunction with the accompanying drawings.

Brief Description of the Drawings

[0017] [Figure 1] An example of small data transmission using a preset uplink grant is shown according to an embodiment of the present disclosure. [Figure 2] An example of the association between a synchronization signal block and an uplink grant according to an embodiment of the present disclosure is shown. [Figure 3] Another example of the association between a synchronization signal block and an uplink grant according to an embodiment of the present disclosure is shown. [Figure 4] A flowchart for small data transmission using preconfigured uplink resources is shown according to an embodiment of the present disclosure. [Figure 5] A flowchart for small data transmission using preconfigured uplink resources is shown according to an embodiment of the present disclosure. [Figure 6] A flowchart for generating a MAC (medium access control) protocol data unit (PDU) for small data is shown according to an embodiment of the present disclosure. [Figure 7] A flowchart for generating a MAC PDU for small data transmission is shown according to an embodiment of the present disclosure. [Figure 8] A block diagram of a terminal according to an embodiment of the present disclosure. [Figure 9] A block diagram of a base station according to an embodiment of the present disclosure.

Modes for Carrying Out the Invention

[0018] Throughout the drawings, like reference numerals are understood to refer to like parts, components, and structures.

[0019] The following description, with reference to the accompanying drawings, is provided to aid in a comprehensive understanding of the various embodiments of this disclosure, as defined by the claims and their equivalents. It includes various specific details to aid in the corresponding understanding, but these should be considered merely illustrative. Accordingly, those skilled in the art will recognize that various changes and modifications of the various embodiments described herein can be made without departing from the scope and spirit of this disclosure. Furthermore, for clarity and brevity, descriptions of well-known functions and configurations may be omitted.

[0020] The terms and words used in the following description and claims are not limited to their bibliographic meanings, but are used solely to enable the inventors to have a clear and consistent understanding of the Disclosure. Accordingly, it should be obvious to those skilled in the art that the following descriptions of various embodiments of the Disclosure are provided merely as examples and are not intended to limit the Disclosure as defined by the appended claims and their equivalents.

[0021] It should be understood that the singular forms "a," "an," and "the" include plural objects unless the context otherwise makes it clear. Therefore, for example, a reference to "constituent surfaces" includes references to one or more such surfaces.

[0022] The term "substantially" means that the cited characteristic, parameter, or value does not need to be exactly achieved, but deviations or variations, including, for example, tolerances, measurement errors, measurement accuracy limits, and other factors known to those skilled in the art, may occur to the extent that they do not negate the effect that the characteristic is intended to provide.

[0023] Those skilled in the art will know that the blocks of a flowchart (or sequence diagram) and combinations of flowcharts can be represented and performed by computer program instructions. Such computer program instructions can be loaded onto the processor of a general-purpose computer, a special-purpose computer, or a programmable data processing device. When the loaded program instructions are performed by the processor, this generates means for performing the functions described in the flowchart. Since computer program instructions can be stored in computer-readable memory usable by a special-purpose computer or a programmable data processing device, it is also possible to produce products that perform the functions described in the flowchart. Since computer program instructions can be loaded onto a computer or a programmable data processing device, when performed as a process, this can perform the operations of the functions described in the flowchart.

[0024] A block in a flowchart can correspond to, or is part of, a module, segment, or code containing one or more executable instructions that embody one or more logical functions. In some cases, the function indicated by a block may be performed in a different order than the sequenced steps. For example, two blocks listed in a sequence may be performed simultaneously or in reverse order.

[0025] In this description, the words "unit" and "module" can refer to software or hardware components, such as an FPGA (field-programmable gate array) or application-specific integrated circuit (ASIC), that can perform functions or operations. However, "unit," etc., are not limited to hardware or software. Units, etc., can reside in an addressable storage medium or be configured to drive one or more processors. Units, etc., can refer to software components, object-oriented software components, class components, task components, processes, functions, attributes, procedures, subroutines, program code segments, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, or variables. The functions provided by components and units can be combinations of smaller components and units, and can be combined with other components to configure larger components and units. Components and units can be configured to drive a device or one or more processors on a secure multimedia card.

[0026] Prior to any detailed explanation, terms or definitions necessary for understanding this disclosure will be explained. However, such terms should be interpreted in a non-restrictive manner.

[0027] A "base station (BS)" is an entity that communicates with user equipment (UE) and can be referred to as a BS, BTS (base transceiver station), NB (node ​​B), eNB (evolved NB), access point (AP), 5G NB (5GNB), or gNB (next generation node B).

[0028] "UE" is an entity that communicates with BS and can be referred to as a UE, device, mobile station (MS), mobile equipment (ME), or terminal.

[0029] In recent years, a variety of broadband wireless technologies have been developed to meet the growing number of broadband subscribers and to provide a greater number of superior applications and services. Second-generation wireless communication systems were developed to ensure user mobility and provide voice services. Third-generation wireless communication systems support not only voice services but also data services. Recently, fourth-generation wireless communication systems were developed to provide high-speed data services. However, currently, fourth-generation wireless communication systems face difficulties due to a lack of resources to meet the increasing demand for high-speed data services. Therefore, fifth-generation wireless communication systems are being developed to meet the increasing demand for high-speed data services and to support ultra-reliable and low-latency applications.

[0030] Fifth-generation wireless communication systems will be implemented not only in lower frequency bands but also in higher frequency (mmWave) bands such as the 10GHz-100GHz band, achieving even higher data transmission rates. To mitigate radio wave propagation loss and increase transmission distance, beamforming, massive MIMO (Multiple-Input Multiple-Output), FD-MIMO (Full Dimensional MIMO), array antennas, analog beamforming, and large-scale antenna technologies are considered in the design of fifth-generation wireless communication systems. Furthermore, fifth-generation wireless communication systems are expected to solve different use cases with very different requirements in terms of data transmission rate, latency, reliability, and mobility. However, the design of the wireless interface (air-interface) of fifth-generation wireless communication systems is expected to be flexible enough to serve UEs with very different capabilities depending on the use case and market segment in which the UE serves the end customer. Some exemplary use cases that 5th generation wireless communication systems are expected to address include enhanced Mobile Broadband (eMBB), massive Machine Type Communication (m-MTC), and ultra-reliable low latency communication (URLLC). eMBB requirements, such as data transmission rates of tens of Gbps, low latency, and high mobility, address the market segment representing wireless broadband subscribers who need internet connectivity anytime, anywhere through related technologies. m-MTC requirements, such as extremely high connection density, infrequent data transmission, very long battery life, and low mobility addresses, address the market segment representing the Internet of Things (IoT) / Internet of Everything (IoE), which envisions connecting billions of devices.URLLC requirements such as extremely low latency, very high reliability, and variable mobility address market segments such as industrial automation applications and vehicle-to-vehicle / vehicle-to-infrastructure communications, which are expected to be one of the enablers for autonomous vehicles.

[0031] In fifth-generation wireless communication systems operating in higher frequency (mmWave) bands, UEs and gNBs communicate with each other using beamforming. Beamforming technology is used to mitigate propagation path loss and increase propagation distance for communication in higher frequency bands. Beamforming improves transmit and receive performance by using high-gain antennas. Beamforming can be classified into transmit (TX) beamforming, which is performed at the transmitting end, and receive (RX) beamforming, which is performed at the receiving end. Generally, TX beamforming increases directivity by using multiple antennas to ensure that the area to which propagation arrives is densely located in a specific direction.

[0032] In this situation, the aggregation of multiple antennas can be called an antenna array, and each antenna included in the array can be called an array element. Antenna arrays can be configured in various forms, such as linear arrays and planar arrays. Using TX beamforming increases the directivity of the signal and increases the propagation distance. Also, since the signal is hardly transmitted in directions other than the directivity direction, signal interference acting on other receiving ends is greatly reduced. The receiving end can perform beamforming on the RX signal by using an RX antenna array. RX beamforming increases the strength of the RX signal transmitted in a specific direction by concentrating propagation in that direction, and provides the effect of blocking interference signals by excluding signals transmitted in directions other than the specific direction from the RX signal.

[0033] By using beamforming technology, a transmitter can create multiple transmit beam patterns in different directions. Each of these transmit beam patterns can also be called a TX beam. Radio communication systems operating at high frequencies use multiple narrow TX beams to transmit signals within a cell, as each narrow TX beam provides coverage to a portion of the cell. The narrower the TX beam, the higher the antenna gain, and therefore the longer the propagation distance of the signal transmitted using beamforming. A receiver can also create multiple RX beam patterns in different directions. Each of these receiver beam patterns can also be called an RX beam.

[0034] Fifth-generation wireless communication systems support independent operating modes and dual connectivity (DC). In DC, a multiplexed Rx / Tx UE can be configured to leverage resources provided by two different nodes (or NBs) connected via a non-ideal backhaul. One node acts as the Master Node (MN), and the other as the Secondary Node (SN). The MN and SN are connected via a network interface, with at least the MN connected to the core network. NR also supports MR-DC (Multi-RAT Dual Connectivity) operation, meaning that a UE in RRC_CONNECTED is located on two different nodes connected via a non-ideal backhaul and configured to leverage radio resources provided by two separate schedulers that provide E-UTRA (Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access) (i.e., when the node is an ng-eNB) or NR (New Radio) access (i.e., when the node is a gNB). For an RRC_CONNECTED UE without carrier aggregation / dual connectivity (CA / DC) configured, NR has only one serving cell, including a PCell (primary cell). For an RRC_CONNECTED UE with CA / DC configured, the term "serving cell" is used to refer to a set of cells including a Special Cell and all secondary cells (SCells). In NR, the Master Cell Group (Master Cell) The term Group (MCG) refers to a group of serving cells associated with a master node that includes a PCell and, selectively, one or more SCells.In NR, the term Secondary Cell Group (SCG) refers to a group of serving cells associated with a secondary node that includes a primary SCell (PSCell) and one or more SCells selectively. In NR, a PCell refers to a serving cell in an MCG operating on the primary frequency, where the UE performs a connection establishment procedure or initiates a reconfiguration procedure. In NR for a CA-configured UE, a SCell is a cell that provides additional radio resources on top of a Special Cell. A PSCell refers to a serving cell in an SCG that the UE randomly accesses when performing a Reconfiguration with Sync procedure. In dual-connection operation, the term SpCell (i.e., Special Cell) refers to a PCell in an MCG or a PSCell in an SCG; otherwise, the term Special Cell refers to a PCell.

[0035] In a fifth-generation wireless communication system (or NR), a Physical Downlink Control Channel (PDCCH) is used to schedule downlink (DL) transmissions on a Physical Downlink Shared Channel (PDSCH) and uplink (UL) transmissions on a Physical Uplink Shared Channel (PUSCH), where Downlink Control Information (DCI) on the PDCCH includes at least a downlink assignment including modulation and coding format, resource allocation, and hybrid-automatic repeat request (ARQ; HARQ) information related to downlink scheduling (DL-SCH); and an uplink scheduling grant including at least a modulation and coding format, resource allocation, and HARQ information related to uplink scheduling (UL-SCH).In addition to scheduling, PDCCH can be used to activate and deactivate PUSCH transmits set with a set grant; activate and deactivate PDSCH semi-persistent transmits; notify one or more UEs of the slot format; notify one or more UEs of physical resource blocks (PRBs) and orthogonal frequency division multiplexing (OFDM) symbols that the UEs can assume are not intended for transmission; transmit transmit power control (TPC) commands to physical uplink control channels (PUCCH) and PUSCH; transmit one or more TPC commands for the transmission of sounding reference signals (SRS) by one or more UEs; switch the active bandwidth portion of the UEs; and initiate random access procedures.

[0036] The UE monitors the PDCCH candidate set in monitoring occasions configured in one or more configured CORESETs (CONtrol REsource SETs) with corresponding search space settings. A CORESET is configured with PRB sets having durations of 1 to 3 OFDM symbols. Resource units REG (Resource Element Groups) and CCE (Control Channel Element) are defined within a CORESET where each CCE is configured in a REG set. Control channels are formed by the aggregation of CCEs. Different code rates for control channels are achieved by aggregating different numbers of CCEs. Interleaved and non-interleaved CCE-REG mappings are supported in the CORESET. Polar coding is used for PDCCHs. Each resource element group that returns a PDCCH returns its own demodulation reference signal (DMRS). PDCCH uses QPSK (Quadrature Phase-Shift Keying) modulation.

[0037] In NR, the search space setting list is signaled by gNB for each configured bandwidth part (BWP), where each search setting is uniquely identified by an identifier. Identifiers for search space settings used for specific purposes, such as paging reception, SI reception, and random access response reception, are explicitly signaled by gNB. In NR, a search space setting includes the parameters Monitoring-periodicity-PDCCH-slot, Monitoring-offset-PDCCH-slot, Monitoring-symbols-PDCCH-in-slot, and duration. The UE monitors PDCCH monitoring occasions within a slot using the parameters PDCCH monitoring period (Monitoring-periodicity-PDCCH-slot), PDCCH monitoring offset (Monitoring-offset-PDCCH-slot), and PDCCH monitoring pattern (Monitoring-symbol-PDCCH-in-slot). The PDCCH monitoring occasion is in slot "x" or x+duration, where the slot containing the number "x" in the radio frame containing the number "y" satisfies equation 1 below:

[0038] [Formula 1]

[0039] (y*(number of radio frame slots)+x-Monitoring-offset-PDCCH-slot)mod(Monitoring-periodicity-PDCCH-slot)=0

[0040] The start symbol for the PDCCH monitoring occasion in each slot that has a PDCCH monitoring occasion is given by Monitoring-symbols-PDCCH-in-slot. The length (in symbols) of the PDCCH monitoring occasion is given in the CORESET associated with the search space. The search space setting includes the identifier of the associated CORESET setting. The list of CORESET settings is signaled by gNB for each set BWP, where each CORESET setting is uniquely identified by its identifier. Note that the duration of each radio frame is 10 ms. Radio frames are identified by radio frame number or system frame number. Each radio frame contains a variety of slots, the number of slots in the radio frame and the duration of the slots vary depending on the subcarrier spacing. The number of slots and the duration of the slots in a radio frame vary because radio frames for each supported subcarrier spacing (SCS) are predefined in NR. Each CORESET setting is associated with a list of TCI (transmission configuration indicator) states. One DL reference signal (RS ID (SSB or CSI-RS (channel state information (CSI) RS))) is set for each TCI state. A list of TCI states corresponding to the CORESET setting is signaled by the gNB via RRC signaling. One of the TCI states in the TCI state list is activated and shown to the UE by the gNB. The TCI state indicates the DL TX beam that the gNB uses for PDCCH transmission during PDCCH monitoring occasions in the search space (the DL TX beam is QCLed (quasi-co-located (QCLed)) with the SSB / CSI RS of the TCI state).

[0041] In NR, bandwidth adaptation (BA) is supported. With BA, the receive and transmit bandwidth of a UE does not need to be as large as the cell bandwidth and can be adjusted: width can be ordered to change (e.g., to reduce during periods of low activity to conserve power); position can be moved in the frequency domain (e.g., to increase scheduling flexibility); and subcarrier spacing can be ordered to change (e.g., to accommodate different services). A subset of the total cell bandwidth of a cell is called a bandwidth portion (BWP).

[0042] BA is achieved by setting BWPs on the RRC-connected UE and informing the UE which of the set BWPs is currently active. When BA is set, the UE should only monitor the PDCCH on one active BWP, i.e., it does not need to monitor the PDCCH on the entire DL frequency of the serving cell. In the RRC-connected state, the UE has one or more DL and UL BWPs set for each set serving cell (i.e., PCell or SCell). For an activated serving cell, there is always one active UL and DL BWP at any given time. BWP switching for a serving cell is used to activate inactive BWPs and simultaneously deactivate active BWPs. BWP switching is controlled by the MAC (medium access control) entity itself at the start of a PDCCH indicating downlink allocation or uplink grant, a bwp-InactivityTimer, RRC signaling, or random access procedure. Upon addition of an SpCell or activation of an SCell, the DL BWP and UL BWP, indicated by firstActiveDownlinkBWP-Id and firstActiveUplinkBWP-Id, respectively, are active without receiving a PDCCH indicating downlink allocation or uplink grant. The active BWP for a serving cell is indicated by an RRC or PDCCH. In the case of an unpaired spectrum, the DL BWP is paired with the UL BWP, and BWP switching is common to both UL and DL. Upon expiration of the BWP deactivation timer, the UE switches the active DL BWP to the base DL BWP or initial DL BWP (if a base DL BWP is not set).

[0043] 5G wireless communication systems support random access (RA). RA is used to achieve UL time synchronization. RA is used during initial access, handover, radio resource control (RRC) reconnection procedures, scheduling request transmission, secondary cell group (SCG) addition / modification, beam fault recovery, and transmission of data or control information in UL by unsynchronized UEs in the RRC CONNECTED state. Various types of random access procedures are supported.

[0044] Contention-based random access (CBRA): This is also known as four-stage CBRA. In this type of RA, the UE first sends an RA preamble (also called Msg1 (message1)) and then waits for a random access response (RAR) in the RAR window. The RAR is also called Msg2 (message2). The next generation node B (gNB) sends the RAR over the physical downlink shared channel (PDSCH). The PDCCH that schedules the PDSCH to send the RAR back is addressed to the RA-RNTI (RA-radio network temporary identifier). The RA-RNTI identifies the time-frequency resource (also called a physical RA channel (PRACH) occasion, or PRACH transmit (TX) occasion, or RA channel (RACH) occasion) detected by the gNB in ​​the RA preamble. RA-RNTI is calculated as follows: RA-RNTI = 1 + s_id + 14*t_id + 14*80*f_id + 14*80*8*ul_carrier_id, where s_id is the index of the first orthogonal frequency division multiplexing (OFDM) symbol of the PRACH occasion in which the UE transmitted Msg1, i.e., the RA preamble; 0 ≤ s_id < 14; t_id is the index of the first slot of the PRACH occasion (0 ≤ t_id < 80); f_id is the index of the PRACH occasion in the slot in the frequency domain (0 ≤ f_id < 8); ul_carrier_id is 0 for the NUL (normal UL) carrier used for Msg1 transmission, and 1 for the SUL (supplementary UL) carrier. The various RARs for diverse RA preambles detected by gNB can be multiplexed by gNB into the same RAR MAC (medium access control) PDU (protocol data unit).A RAR within a MAC PDU corresponds to a UE sending an RA preamble if the RAR contains the RA preamble identifier (RAPID) of the RA preamble sent by the UE. If no RAR corresponding to an RA preamble is received during the RAR window, and the UE has not yet sent an RA preamble within the configurable number of times (configured by the gNB in ​​the RACH setting), the UE returns to the first stage, i.e., selects an RA resource (preamble / PRACH occasion) and sends an RA preamble. A backoff can be applied before returning to the first stage.

[0045] If a RAR corresponding to the RA preamble transmission is received, the UE transmits Msg3 (message3) with the UL grant received in the RAR. Msg3 may contain messages such as RRC connection requests, RRC connection reconfiguration requests, RRC handover confirmations, scheduling requests, and SI requests. Msg3 may also contain the UE identity (i.e., cell-radio network temporary identifier (C-RNTI), or S-TMSI (system architecture evolution (SAE)-temporary mobile subscriber identity), or a random number). After transmitting Msg3, the UE starts the competition resolution timer. If the UE receives a PDCCH addressed to the C-RNTI included in Msg3 while the competition resolution timer is running, the competition resolution is considered successful, the competition resolution timer is terminated, and the RA procedure is completed. While the competition resolution timer is running, if the UE receives a competition resolution MAC control element (CE) containing the UE's competition resolution identity (e.g., the first X bits of the Common Control Channel (CCCH) Service Data Unit (SDU) sent in Msg3), the competition resolution is considered successful, the competition resolution timer is terminated, and the RA procedure is completed. If the competition resolution timer expires and the UE has not yet sent an RA preamble within the configurable number of times, the UE returns to the first stage, i.e., selects an RA resource (preamble / PRACH occasion) and sends an RA preamble. A backoff may be applied before returning to the first stage.

[0046] Contention-free random access (CFRA): Also known as legacy CFRA or four-stage CFRA. CFRA procedures are used in scenarios where low latency is required, such as handovers and timing advance setup for Scell. The eNB (or gNB) assigns a dedicated RA preamble to the UE. The UE transmits the dedicated RA preamble. The eNB (or gNB) transmits the RAR over a PDSCH addressed to RA-RNTI. The RAR conveys the RA preamble identifier and timing alignment information. The RAR may also include a UL grant. The RAR is transmitted within a RAR window similar to that of a CBRA procedure. A CFRA is considered successfully completed after receiving the RAR containing the RAPID of the RA preamble transmitted by the UE. If the RA is initiated for a BFR, the CFRA is considered successfully completed when a PDCCH addressed to C-RNTI is received in the search space for the BFR. If the RAR window expires, the RA does not complete successfully, and the UE has not yet sent an RA preamble within the configurable number of times (as set by the gNB in ​​the RACH setting), the UE resends the RA preamble.

[0047] For certain events such as handovers and BFRs, if a dedicated preamble is assigned to the UE, during the first stage of the RA procedure, i.e., during RA resource selection for Msg1 transmission, the UE decides whether to transmit a dedicated or non-dedicated preamble. Dedicated preambles are generally provided to a subset of SSB / CSI RS (channel state information reference signals). If there are no SSB / CSI RS with a critical DL RSRP (reference signal received power) or higher among those provided with CFRA resources (i.e., dedicated preamble / PRACH occasions) by the gNB, the UE selects a non-dedicated preamble. Otherwise, the UE selects a dedicated preamble. During the RA procedure, one RA attempt may be a CFRA, while other random access attempts may be CBRAs.

[0048] Two-stage competition-based random access (two-stage CBRA): In the first stage, the UE sends a random access preamble on PRACH and a payload (i.e., MAC PDU) on PUSCH. The transmission of the random access preamble and payload is also called MsgA. In the second stage, after sending MsgA, the UE monitors for a response from the network (i.e., gNB) within a set window. The response is also called MsgB. If a CCCH SDU is transmitted in the MsgA payload, the UE performs competition resolution using the competition resolution information in MsgB. Competition resolution is successful if the competition resolution identity received in MsgB matches the first 48 bits of the CCCH SDU transmitted in MsgA. If a C-RNTI is transmitted in the MsgA payload, competition resolution is successful if the UE receives a PDCCH addressed to the C-RNTI. If competition resolution is successful, the RA procedure is considered to have completed successfully. Instead of competition resolution information corresponding to the transmitted MSGA, MsgB may contain fallback information corresponding to the random access preamble transmitted in MsgA. If fallback information is received, the UE transmits Msg3, as in the CBRA procedure, and performs competition resolution using Msg4. If competition resolution is successful, the RA procedure is considered to have completed successfully. If competition resolution fails during the fallback (i.e., when Msg3 is transmitted), the UE retransmits MsgA. After the UE transmits MsgA, if the configured window for monitoring network responses has expired and the UE has not received a MsgB containing competition resolution information or fallback information as described above, the UE retransmits MsgA. If the RA procedure does not complete successfully after transmitting a configurable number of MsgA's, the UE falls back to the 4-stage RACH procedure, i.e., the UE transmits only the PRACH preamble.

[0049] The MsgA payload may include one or more of the following: CCCH SDU, Dedicated Control Channel (DCCH) SDU, Dedicated Traffic Channel (DTCH) SDU, Buffer Status Report (BSR) MAC CE, Power Headroom Report (PHR) MAC CE, SSB information, C-RNTI MAC CE, or padding. The MsgA may include a UE ID (e.g., Random ID, S-TMSI, C-RNTI, Restart ID, etc.) along with the preamble in the first stage. The UE ID may be included in the MAC PDU of the MsgA. UE IDs such as C-RNTI may be returned with a MAC CE included in the MAC PDU. Other UE IDs (e.g., Random ID, S-TMSI, C-RNTI, Restart ID, etc.) may be returned with a CCCH SDU. The UE ID can be one of the following: Random ID, S-TMSI, C-RNTI, Restart ID, IMSI (International Mobile Subscriber Identity), Idle Mode ID, or Inactive Mode ID. The UE ID can differ in different scenarios in which the UE performs the RA procedure. When the UE performs RA after powering on (before attaching to the network), the UE ID is the Random ID. When the UE performs RA in the IDLE state after attaching to the network, the UE ID is the S-TMSI. If the UE has an assigned C-RNTI (e.g., while connected), the UE ID is the C-RNTI. If the UE is in the INACTIVE state, the UE ID is the Restart ID. Additional control information can be attached to the UE ID and sent to the MsgA. This control information can be included in the MAC PDU of the MsgA.Control information may include one or more of the following: connection request indication, connection restart request indication, SI request indication, buffer status indication, beam information (e.g., one or more DL TX beam IDs or SSB IDs), BFR indication / information, data indicator, cell / base station (BS) / transmit / receive point (TRP) switching indication, connection reset indication, reset complete or handover complete message.

[0050] Two-stage non-competitive random access (two-stage CFRA): In this case, the gNB allocates a dedicated random access preamble and a physical uplink shared channel (PUSCH) resource for MsgA transmission to the UE. The PRACH occasion used for preamble transmission may also be indicated. In the first stage of the two-stage CFRA, the UE transmits a random access preamble over PRACH using the CFRA resources (i.e., dedicated preamble / PUSCH resource / PRACH occasion) and transmits the payload over PUSCH. In the second stage of the two-stage CFRA, after MsgA transmission, the UE monitors for a response from the network (i.e., the gNB) within a set window. If the UE receives a PDCCH addressed to C-RNTI, the RA procedure is considered successfully completed. If the UE receives fallback information corresponding to the transmitted preamble, the RA procedure is considered successfully completed.

[0051] For certain events such as handovers and BFRs, once dedicated preambles and PUSCH resources are allocated to the UE, during the first stage of the RA procedure, i.e., during RA resource selection for sending MsgA, the UE decides whether to send a dedicated preamble or a non-dedicated preamble. Dedicated preambles are generally provided to a subset of SSB / CSI RSs. If there are no SSB / CSI RSs with DL RSRPs above a critical value among those provided with CFRA resources (i.e., dedicated preamble / PRACH occasion / PUSCH resources) by the gNB, the UE chooses a non-dedicated preamble. Otherwise, the UE chooses a dedicated preamble. During the RA procedure, one RA attempt may be a two-stage CFRA, while other RA attempts may be two-stage CBRAs.

[0052] When an RA procedure is initiated, the UE first selects a carrier (i.e., SUL or NUL). If the carrier to be used for the RA procedure is explicitly signaled by the gNB, the UE selects the signaled carrier to perform the RA procedure. If the carrier to be used for the RA procedure is not explicitly signaled by the gNB; and the serving cell for the RA procedure has set SUL; and the RSRP of the DL path loss criterion is less than rsrp-ThresholdSSB-SUL, the UE selects the SUL carrier to perform the RA procedure. Otherwise, the UE selects the NUL carrier to perform the RA procedure. If a UL carrier is selected, the UE determines the UL and DL BWP during the RA procedure as specified in section 5.15 of technical specification (TS) 38.321. The UE then decides whether to perform a two-stage or four-stage RA during such an RA procedure.

[0053] -If such a random access procedure is initiated by a PDCCH sequence and the ra-PreambleIndex explicitly provided by the PDCCH is not 0b000000, the UE selects a 4-stage RACH.

[0054] - Otherwise, if a two-step non-competitive random access resource is signaled by a gNB for such a random access procedure, the UE will select two-step RACH.

[0055] - Otherwise, if a 4-stage non-competitive random access resource is signaled by a gNB for such a random access procedure, the UE will select 4-stage RACH.

[0056] - Otherwise, if the UL BWP selected for such a random access procedure configures only two-stage RACH resources, the UE will select two-stage RACH.

[0057] - Otherwise, if the UL BWP selected for such a random access procedure configures only 4-stage RACH resources, the UE will select 4-stage RACH.

[0058] -Otherwise, the UL BWP selected for such a random access procedure will configure either the 2-stage or 4-stage RACH resource.

[0059] - If the RSRP for downlink path loss criteria is below the set critical value, the UE selects 4-stage RACH. Otherwise, the UE selects 2-stage RACH.

[0060] In a fifth-generation wireless communication system, a cell broadcast SSB (Synchronization Signal and PBCH block) node B (gNB) or base station consists of a PSS (primary synchronization signal), an SSS (secondary synchronization signal), and system information. System information (SI) includes common parameters necessary for communication within the cell. In a fifth-generation wireless communication system (also called next-generation radio or NR), SI is divided into a MIB (master information block) and numerous SIBs (system information blocks), where:

[0061] - The MIB is always transmitted on the BCH with a period of 80ms, repeated within 80ms, and contains the parameters necessary to obtain SIB1 (system information block 1) from the cell.

[0062] -SIB1 is transmitted over DL-SCH with a period of 160ms and a variable transmit repetition rate. The basic transmit repetition rate of SIB1 is 20ms, but the actual transmit repetition rate depends on the network implementation. The scheduling information for SIB1 includes the mapping between SIBs and SI messages, the period of each SI message, and the length of the SI window. The scheduling information for SIB1 includes an indicator for each SI message indicating whether the associated SI message is broadcast or not. If at least one SI message is not broadcast, SIB1 may include random access resources (PRACH preamble and PRACH resources) to request the gNB to broadcast one or more SI messages.

[0063] -SIBs other than SIB1 are returned in SI (System Information) messages transmitted on DL-SCH. Only SIBs with the same period can be mapped to the same SI message. Each SI message is transmitted within a periodically occurring time domain window (called an SI-window, which has the same length for all SI messages). Each SI message is associated with an SI-window, and the SI-windows of different SI messages do not overlap. Only corresponding SI messages are transmitted within a single SI-window. All SIBs except SIB1 can be configured to be cell-specific or region-specific using the indication of SIB1. Cell-specific SIBs are applicable only within the cell that provides the SIB, while region-specific SIBs are applicable within a region called an SI region, which consists of one or more cells and is identified by the systemInformationAreaID.

[0064] In a 5th generation wireless communication system, the RRC can be in one of the following states: RRC_IDLE, RRC_INACTIVE, or RRC_CONNECTED. The UE is in the RRC_CONNECTED or RRC_INACTIVE state when an RRC connection is established. Otherwise, i.e., if an RRC connection is not established, the UE is in the RRC_IDLE state. The RRC states can also be characterized as follows:

[0065] In RRC_IDLE, UE-specific DRX (discontinuous) can be configured by the higher hierarchy. The UE can monitor short messages sent via DCI in paging RNTI (P-RNTI); monitor paging channels for CN paging using 5G-S-TMSI (5G-S-temoprary mobile subscriber identity); perform adjacent cell measurements and cell (re)selection; acquire system information and send SI requests (if configured); and log available measurements along with location and time for configured UEs.

[0066] In RRC_INACTIVE, the UE-specific DRX can be configured by the higher hierarchy or the RRC hierarchy; the UE stores the UE inactive AS context. The RAN-based notification area is configured by the RRC hierarchy. The UE monitors short messages sent via DCI in P-RNTI; monitors paging channels for CN paging using 5G-S-TMSI and RAN paging using overall I-RNTI; performs adjacent cell measurement and cell (re)selection; periodically updates the RAN-based notification area when moving outside the configured RAN-based notification area; can acquire system information and send SI requests (if configured); logs available measurements along with their location and time relative to the configured UE.

[0067] In RRC_CONNECTED, the UE stores the AS context and unicast data transmission to / from the UE occurs. The UE, if configured, monitors short messages sent via DCI through P-RNTI; monitors control channels associated with shared data channels to determine if data is scheduled; provides channel quality and feedback information; performs adjacent cell measurements and measurement reports; and obtains system information.

[0068] In RRC_CONNECTED, the network can initiate a suspension of the RRC connection by sending an RRCRlease with a suspend setting. When the RRC connection is suspended, the UE stores the UE inactive AS context and all settings received from the network and switches to the RRC_INACTIVE state (transit). If the UE has an SCG configured, the UE removes the SCG configuration when initiating the RRC connection restart procedure. RRC messages for suspending the RRC connection are integrity protected and encrypted.

[0069] The resumption of a temporarily suspended RRC connection is initiated by the higher hierarchy when the UE needs to switch from the RRC_INACTIVE state to the RRC_CONNECTED state, or by the RRC hierarchy to perform an RNA (RAN-based notification area) update, or by RAN paging from NG-RAN. When the RRC connection is resumed, the network configures the UE using the RRC connection resumption procedure based on the stored UE inactive AS context and any RRC settings received from the network. The RRC connection resumption procedure reactivates AS security and reconfigures the SRB (signaling radio bearer) and DRB (data radio bearer). In response to a request to resume the RRC connection, the network either resumes the suspended RRC connection and sends the UE to RRC_CONNECTED, rejects the request to resume and sends the UE to RRC_INACTIVE (according to the standby timer), directly suspends the RRC connection again and sends the UE to RRC_INACTIVE, directly disconnects the RRC connection and sends the UE to RRC_IDLE, or instructs the UE to initiate NAS-level recovery (in this case, the network sends an RRC configuration message).

[0070] Once the restart procedure is initiated, the UE will

[0071] - The values ​​apply the default L1 parameter values ​​as explicitly stated in the corresponding physical hierarchy specification, except for the parameters provided to SIB1;

[0072] -Apply the basic MAC cell group settings;

[0073] -Apply CCCH settings;

[0074] -Start timer T319;

[0075] -Apply timeAlignmentTimerCommon included in SIB1;

[0076] -Apply the basic SRB1 settings;

[0077] - Set the variable pendingRNA-Update to FALSE;

[0078] -Start sending the RRCResumeRequest message or RRCResumeRequest1;

[0079] - Except for the following, stored QoS flows and K from the stored UE inactive AS context for RRC settings, RoHC status, DRB mapping rules gNB and K RRCint Restore the key;

[0080] *-masterCellGroup;

[0081] *-If stored, mrdc-SecondaryCellGroup; and

[0082] *-pdcp-Config;

[0083] Set -resumeMAC-I to the 16 least significant bits of the MAC-I calculated via the following:

[0084] *ASN.1 encoded according to clause 8 (i.e., multiples of 8 bits) VarResumeMAC-Input;

[0085] *K of UE inactive AS context RRCint Key and previously configured integrity protection algorithm; and

[0086] *All input bits for COUNT, BEARER, and DIRECTION set to binary 1;

[0087] -Derive the current K using the stored nextHopChainingCount value gNB K key or NH based on K gNB Derive the key;

[0088] -K RRCenc K key, K RRCint K key, K UPint K key, and K UPenc Derive the key;

[0089] -Set the lower layer to apply integrity protection to all signaling radio bearers except SRB0 using the configured algorithm and K RRCint K key and K UPint That is, integrity protection must be applied to all subsequent messages transmitted and received by the UE;

[0090] -Apply encryption to all signaling radio bearers except SRB0 and set the lower layer to apply the configured encryption algorithm, K RRCenc K key and derived K UPenc Key, that is, the encryption setting must be applied to all subsequent messages transmitted and received by the UE;

[0091] -Reset the PDCP entity for SRB1;

[0092] -Resume SRB1;

[0093] -Send RRCResumeRequest or RRCResumeRequest1.

[0094] In a 4G wireless communication system, a UE can be configured with a pre-configured UL resource for sending small data during RRC_IDLE. The UE receives a PUSCH resource for sending small data (e.g., a periodic UL grant) in the RRC disconnection message. If the amount of data the UE is sending during RRC_IDLE is small, and the UE is camping in the same cell where it received the UL grant in the RRC disconnection message, and the UE has a valid TA, the UE selects the fastest UL grant and sends a MAC PDU with the selected UL grant. The UE waits for a response from the network within a configured time interval. For a response, the UE monitors the PDCCH addressed to the RNTI assigned to the UE in the RRC disconnection message. If no response is received, the small data transmission is considered to have failed.

[0095] 5G wireless communication systems support multiple beams, multiple UL carriers, multiple BWPs, and search spaces for PDCCH monitoring. All such aspects are not considered in existing procedures. Small data transmission procedures must be improved to support multiple beams, multiple UL carriers, multiple BWPs, and search spaces for PDCCH monitoring.

[0096] In 5G wireless communication systems, the logical channel prioritization (LCP) procedure is used to generate MAC PDUs. The Logical Channel Control (RRC) controls the LCP procedure by setting mapping restrictions for each logical channel.

[0097] -allowedSCS-List sets the allowed subcarrier intervals for transmission;

[0098] -maxPUSCH-Duration sets the maximum push duration allowed for transmission;

[0099] -configureGrantType1Allowed sets whether the configured grant type 1 can be used for sending;

[0100] -allowedServingCells sets the cells that are allowed to be sent;

[0101] -allowedCG-List sets the allowed grants configured for transmission;

[0102] -allowedPHY-PriorityIndex sets the allowed PHY priority index for dynamic grants for sending.

[0103] In the case of SDT, DRB is restarted when RRC connection reactivation is initiated. The question is whether the LCH limit of the stored AS context is applied during MAC PDU generation for small data transmission.

[0104] Example 1 - Operation when restarting the RRC connection for sending small data with RRC_INACTIVE, or operation when starting the small data transmission procedure with RRC_INACTIVE

[0105] The UE is in the RRC_INACTIVE state. While in the RRC_INACTIVE state, the UE initiates the reactivation of the RRC connection for sending small data (if the criteria for sending small data are met). Reactivating the RRC connection for sending small data can also be called the small data transmission procedure. At the start of reactivating the RRC connection for sending small data, or at the start of the small data transmission procedure, the UE performs the following actions:

[0106] - Except for parameters whose values ​​are provided to SIB1, apply the basic L1 parameter values ​​as explicitly stated in the corresponding physical hierarchy specification;

[0107] -Apply the basic MAC cell group settings;

[0108] -Apply CCCH settings;

[0109] - Start the timer (T319 or a new timer set by gNB for small data transmission);

[0110] -Apply timeAlignmentTimerCommon included in SIB1;

[0111] -Apply the basic SRB1 settings;

[0112] - Set the variable pendingRNA-Update to false;

[0113] -Start sending the RRCResumeRequest message or RRCResumeRequest1;

[0114] -When the field useFullResumeID is signaled in SIB1:

[0115] *Select RRCResumeRequest1 as the message to use;

[0116] *Set resumeIdentity to the stored fullI-RNTI value;

[0117] -Other (else):

[0118] *Select RRCResumeRequest as the message to use;

[0119] *Set resumeIdentity to the stored shortI-RNTI value;

[0120] - Except for the following, stored QoS flows and KgNB and K from the stored UE inactive AS context for RRC settings, RoHC status, DRB mapping rulesRRCint Restore the key;

[0121] *masterCellGroup;

[0122] *If stored, mrdc-SecondaryCellGroup; and

[0123] *pdcp-Config;

[0124] Set -resumeMAC-I to the 16 least significant bits of the MAC-I calculated via the following:

[0125] *VarResumeMAC-Input encoded in ASN.1,

[0126] *UE inactive AS context K RRCint The key and the previously set integrity protection algorithm; and

[0127] *All input bits for COUNT, BEARER, and DIRECTION, which are set to binary 1;

[0128] - Derive the KgNB key based on the current KgNB key or NH using the stored nextHopChainingCount value;

[0129] -K RRCenc Key, K RRCint Key, K UPint Key, and K UPenc Derive the key;

[0130] - The configured algorithm and K RRCint Key and K UPintThe lower tiers are configured to apply integrity protection to all radio bearers except SRB0 using a key; that is, integrity protection must be applied to all subsequent messages and user data sent and received by the UE; only DRBs with previously configured UP integrity protection should have integrity protection reactivated;

[0131] Encryption is applied to all wireless bearers except SRB0, and the configured encryption algorithm, K RRCenc Key and derived K UPenc The lower levels must be configured to apply the key; that is, the encryption settings must be applied to all subsequent messages and data sent and received by the UE.

[0132] The UE reconfigures the PDCP entities for all SRBs and all DRBs (or reconfigures the PDCP entities for SRB1 and all DRBs); note that the UE applies the PDCP settings from the stored AS context to the reconfigured PDCP entities of DRB and SRB2. In one embodiment, whether to apply the PDCP settings from the stored AS context or the base PDCP settings can be indicated by the gNB in ​​an RRCRlease message or an RRCReconfiguration message, and the UE applies the PDCP settings from the stored AS context, thereby applying the base PDCP settings to the reconfigured PDCP entities of DRB and SRB2.

[0133] - Reconfigure the RLC entities for DRB (note that when the UE enters an inactive state, the RLC entities for SRB1 are reconfigured). The UE applies the RLC settings from the stored AS context to the reconfigured RLC entities of DRB and SRB2. In one embodiment, whether to apply the RLC settings from the stored AS context or the base RLC settings can be indicated by the gNB in ​​the RRCRlease message or RRCReconfiguration message, and the UE applies the RLC settings from the stored AS context, thereby applying the base RLC settings to the reconfigured RLC entities of DRB and SRB2.

[0134] - Restart all SRBs and all DRBs (or restart SRB1 and all DRBs);

[0135] *When the connection is resumed, the point at which the PDCP provides the DTCH SDU to the lower tier must also be specified. The RRC can indicate this to the PDCP when the DRB is resumed.

[0136] - Send RRCResumeRequest or RRCResumeRequest1. User data is encrypted (only for DRBs with UP integrity protection enabled), integrity protected, and sent over the DTCH multiplexed with the RRCResumeRequest / RRCResumeRequest1 message over the CCCH. Some support information such as BSR (regular or truncated) may also be included; a new MAC CE indicating a UE has more UL data, or the UE expects / will expect DL data in response to the UL data, or includes SS-RSRP or CQI; an indication in an RRC message indicating a UE has more UL data, or the UE expects DL data in response to the UL data. Note that such transmissions are made in Msg3 or MsgA for RACH-based small data transmissions and in pre-configured UL grants for non-RACH-based small data transmissions.

[0137] -In the alternative implementation, instead of sending an RRCResumeRequest or RRCResumeRequest1 along with the uplink data, integrity-protected uplink data is sent. No RRCResumeRequest or RRCResumeRequest1 message is sent. The gNB can authenticate the UE based on the MAC-I received along with the uplink data. Such transmissions are made in Msg3 or MsgA for RACH-based small data transmissions, and in a pre-configured UL grant for non-RACH-based small data transmissions.

[0138] Instead of restarting all DRBs and reconfiguring the PDCP / RLC entities for all DRBs as described above, the UE restarts and reconfigures only those DRBs that allow small data transmissions.

[0139] - DRBs that allow small data transmission can be signaled by gNB (e.g., in an RRCRlease message or any other RRC signaling message). One or more DRB identities of a DRB that allows small data transmission can be included in an RRCRlease message or any other RRC signaling message, such as an RRCReconfiguration message. Alternatively, an indicator (e.g., SDTAllowed is set to TRUE) can be included in the DRB configuration to indicate that SDT is allowed for that DRB. If SDTAllowed is set to FALSE or not included, the UE assumes that SDT is not allowed for that DRB.

[0140] -In one embodiment, a DRB is considered permitted for small data transmission if data from the LCH of such a DRB is permitted to be transmitted by LCH restrictions (allowedSCS-List, maxPUSCH-Duration, configureGrantType1Allowed, allowedServingCells, allowedCG-List, and allowedPHY-PriorityIndex) with UL grants for small data transmission. One or more LCH restrictions are set in the LCH settings of the LCH associated with the DRB. allowedSCS-List includes setting the subcarrier interval allowed for transmission; maxPUSCH-Duration setting the maximum push duration allowed for transmission; configureGrantType1Allowed setting whether a set grant type 1 can be used for transmission; allowedServingCells setting the cells allowed for transmission; allowedCG-List setting the allowed grants set for transmission; and allowedPHY-PriorityIndex setting the allowed PHY priority index for dynamic grants for transmission. For example, if the SCS for UL grants for small data transmission is SCS X, and the LCH for DRB has allowedSCS-List set, and SCS X is not included in allowedSCS-List, then DRB will not be considered for small data transmission.

[0141] Example 2 - Small data transmission using a pre-configured UL grant

[0142] Figure 1 shows an example of small data transmission using a pre-configured uplink grant (also known as a CG type 1PUSCH resource) according to one embodiment of the present disclosure.

[0143] Referring to Figure 1, in RRC_CONNECTED, the UE reports its ability to support a pre-configured PUSCH during RRC_INACTIVE. The UE may, for example, report its preference for configuring a pre-configured PUSCH in a UEAssistanceInformation message. The gNB decides whether to configure a pre-configured PUSCH in RRC_INACTIVE based on the UE's capability, UE type, UE preference, and UL traffic pattern.

[0144] In operation 110, the UE receives a pre-configured PUSCH resource (e.g., CG Type1 resource) for small data transmission (SDT) from the gNB via dedicated signaling (RRCReconfiguration message or RRCRlease message).

[0145] *In one embodiment, such a PUSCH resource for SDT can be applied to a cell in which the UE receives an RRCRlease message or RRCReconfiguration message containing the PUSCH resource for SDT. In one embodiment, such a resource for SDT can be applied to multiple cells. Details regarding the relationship between UL resources for SDT and cells will be described later.

[0146] *Such PUSCH resources are also mapped to SSBs. The mapping rules between PUSCH resources and SSBs will be described later.

[0147] *If multiple UL carriers are supported, pre-configured PUSCH resources for SDT are received separately for SUL and NUL.

[0148] *Pre-configured settings on PUSCH are provided in RRCRlease. For example, such settings can be added when RRCRlease is used to switch to RRC_INACTIVE. These settings can be added to SuspendConfig IE. Alternatively, ConfiguredGrantConfig on Type1 is provided in RRCReconfiguration. An indicator that shows whether the UE can continue to use the grant type 1 configured during RRC_INACTIVE is included in RRCRlease. Additional (pre-configured PUSCH specific) settings can also be provided in RRCRlease.

[0149] While the UE is in RRC_INACTIVE state, SDT using the pre-configured PUSCH resources in operation 120 is initiated. The criteria for SDT using pre-configured PUSCH resources are described later.

[0150] UE selects the UL carrier in operation 130.

[0151] *If SUL is set (for the cell where the UE is performing SDT, i.e., the camped cell of RRC_INACTIVE) and the RSRP of the downlink path loss criterion (e.g., SSB) is less than RSRPThresholdSUL-SDT, the UE selects SUL. Otherwise, the UE selects NUL. RSRPThresholdSUL-SDT is received from the gNB. If RSRPThresholdSUL-SDT is not set, the UE uses RSRPThresholdSUL set in the RACH setting. RSRPThresholdSUL-SDT is a new parameter set to select between SUL and NUL for small data transmissions. This parameter differs from the SUL and NUL carrier selection for random access preamble transmissions. This is because the UL information transmitted in the case of SDT is much larger than in the case of a general random access procedure for connection setup / reopening, requiring much stronger channel conditions to ensure stable transmission.

[0152] Subsequently, the UE selects an SSB with a higher SS-RSRP than RSRPThresholdSSB-SDT from among the SSBs associated with the pre-configured PUSCH resources for SDT on the UL carrier selected in operation 140. RSRPThresholdSSB-SDT is received from the gNB. If RSRPThresholdSSB-SDT is not configured, the UE uses RSRPThresholdSSB configured in the RACH setting. On the selected UL carrier, the UE uses the pre-configured PUSCH resources for SDT on the UL BWP for small data transmission using the pre-configured PUSCH resources. The UL BWP for small data transmission using the pre-configured PUSCH resources will be described later.

[0153] The UE selects the fastest available UL grant corresponding to the selected SSB from the pre-configured PUSCH resources of the UL carrier selected in operation 150.

[0154] The UE generates a MAC PDU for sending small data and sends it when the UL grant selected in operation 160. The UE sends the small data using one of the following options:

[0155] *RRCResumeRequest (or new RRC message) + uplink data (on DTCH). resumeIdentity, ResumeMAC-I, resumeCause for RCRResumeRequest / RRCResumeRequest1. New resumeCause may be introduced to indicate a small data transmission or a small data transmission via a pre-configured PUSCH.

[0156] *RRCResumeRequest (or new RRC message). ResumeIdentity, ResumeMAC-I, resumeCause, NAS container for RRCResumeRequest / RRCResumeRequest1. The NAS container contains UL data.

[0157] *New MAC CE (resumeIdentity, ResumeMAC-I) + uplink data (on DTCH). resumeIdentity is provided for UE identification. ResumeMAC-I is for security purposes.

[0158] Example 2-1 - Details of pre-configured PUSCH resources for SDT

[0159] Related cells

[0160] In one embodiment, a pre-configured PUSCH resource setting for SDT received via dedicated signaling is valid in the cell where the UE receives the setting.

[0161] In one embodiment, the gNB can also signal a pre-configured PUSCH resource for SDT for multiple cells using dedicated signaling.

[0162] *Signaling may include pre-configured PUSCH resource settings and one or more associated cell identities.

[0163] *One setting can be mapped to multiple cells.

[0164] *Cell identity may be skipped due to settings associated with the cell that received the RRCRlease message.

[0165] Related BWP

[0166] In one embodiment, a pre-configured PUSCH resource setting for an SDT received via dedicated signaling is applied to the initial UL BWP (or the pre-configured PUSCH resource setting for the SDT is for the initial UL BWP, or the pre-configured PUSCH resource setting for the SDT is signaled for the initial UL BWP).

[0167] In an alternative embodiment, an applicable BWP for an SDT using a pre-configured PUSCH resource setting (the BWP ID can be indicated from one of the BWPs configured in the RRCReconfiguration message) can be communicated via an RRC message (e.g., RRCRlease, RRCReconfiguration message, or SI message). In one embodiment, the BWP setting may include an indicator that the BWP is applied to an SDT using a pre-configured PUSCH resource setting. In one embodiment, the BWP for an SDT using a pre-configured PUSCH resource setting is a BWP whose setting includes the pre-configured PUSCH resource setting for the SDT. If no applicable BWP is communicated, the pre-configured PUSCH resource setting for the SDT received via dedicated signaling is applied to the initial UL BWP.

[0168] Alternatively, absolute value-based frequency domain information can be signaled.

[0169] Related UL carrier

[0170] In one embodiment, the pre-configured PUSCH resource for SDT is configured separately for NUL and SUL.

[0171] To optimize signaling, if the settings for both SUL and NUL are identical, the setting for SUL can be skipped, and the UE will apply the NUL setting to SUL even if SUL is set to a cell.

[0172] Relationship between SSB and UL Grant

[0173] If the system is deployed at an even higher frequency, the UE needs to know that an association is established between the SSB and the configured grants (i.e., PUSCH occasions / resources).

[0174] In the RRC_INACTIVE state, the UE can only measure SSB, therefore the configured grant is related to SSB.

[0175] To associate the grant with the SSB, the following options are proposed in this disclosure:

[0176] - Option 1: Signaling includes one set grant setting for the UL carrier for SDT.

[0177] *1-1: A list of one or more SSB IDs associated with the grant configuration (or PUSCH resource configuration) is signaled.

[0178] *1-2: Grant settings relate to all transmitted SSBs in a cell where the transmitted SSB is determined by the parameter ssb-PositionsInBurst.

[0179] *In one embodiment, the UL grant is related to the i-th SSB when i = [floor(CURRENT_symbol / periodicity)] modulo N1, where,

[0180] **CURRENT_symbol=[SFN Х numberOfSlotsPerFrame Х numberOfSymbolsPerSlot+frame Х numberOfSymbolsPerSlot's slot number+slot's symbol number]

[0181] **numberOfSlotsPerFrame and numberOfSymbolsPerSlot refer to the number of consecutive slots per frame and the number of consecutive symbols per slot, respectively. numberOfSlotsPerFrame is specific to an SCS and is predefined for each SCS. An SCS is the SCS of the UL BWP associated with the configured grant.**

[0182] **The period (of the symbol) is the period during which the UL grant is set and signaled.

[0183] **SFN is the system frame number to which the configured UL grant is assigned.**

[0184] **The slot number is the starting slot for the configured UL grant.

[0185] **The symbol number is the starting symbol for the configured UL grant.

[0186] **N1 = Number of SSBs**

[0187] **SSBs are mapped in ascending order of SSB ID.

[0188] Figure 2 shows an example of the relationship between a synchronization signal block and an uplink grant (PUSCH occasion / resource) according to one embodiment of the present disclosure.

[0189] Referring to Figure 2, each UL grant / PUSCH occasion is associated with one SSB. The period during which each SSB maps to a UL grant / PUSCH occasion can be said to be an association period, which is a multiple of the grant period in which the association period was set. In Figure 2, the association period includes the four periods during which the grant was set. It should be noted that each UL grant / PUSCH occasion can be mapped to one or more SSBs. In Figure 2, each UL grant / PUSCH occasion is mapped to one SSB.

[0190] - Option 2: Signaling includes multiple grant settings for the UL carrier.

[0191] *In this option, a list of one or more SSB IDs associated with the grant configuration will be signaled in the corresponding configuration. Each UL grant in the grant configuration is associated with an SSB in the list.

[0192] Figure 3 shows another example of the relationship between the synchronization signal block and the uplink grant according to one embodiment of the present disclosure.

[0193] Referring to Figure 3, each grant setting is mapped to one SSB. Therefore, all UL grant / PUSCH occasions in a set grant setting are mapped to the same SSB. If a grant setting is mapped to multiple SSBs, the SSBs can be sequentially mapped to UL grant / PUSCH occasions in a sequential manner, as shown in Figure 2. If the UL grant / PUSCH occasions of a grant setting are also frequency-division multiplexed, the UL grant / PUSCH occasions can be mapped sequentially by frequency first, and then by time.

[0194] Example 2-2 - Criteria for determining whether or not to use pre-configured PUSCH resources for SDT

[0195] The UE can perform SDT using a pre-configured PUSCH resource (or CG resource) if the following conditions are met. In different embodiments, a subset of the following conditions may apply.

[0196] Condition 1: The higher layer requests the resumption of the RRC connection, the resumption request is for mobile originating calls, and the configuration cause is mo-Data; the higher layer requests the resumption of the RRC connection, and the resumption request is for mobile originating calls; the resumption request is for mobile originating calls.

[0197] Condition 2: The UE supports SDT.

[0198] Condition 3: A pre-configured PUSCH resource is signaled in an RRCRlease message along with a suspend indication during a previous suspend procedure, and the UE is in the same cell that received the pre-configured PUSCH resource.

[0199] Condition 4: The UE has a stored value of nextHopChainingCount that was provided in the RRCRlease message along with the interruption indicator during a previous interruption procedure. If nextHopChainingCount is always provided in the RRCRlease message, this condition may be skipped.

[0200] Condition 5: If LCH restrictions on LCPs are applied to the SDT, all LCHs available for data transmission are permitted to be multiplexed with MAC PDUs against pre-configured PUSCH resources for the SDT by the LCH restrictions.

[0201] It should also be noted that the network can indicate a DRB for which SDT is acceptable. In this case, condition 5 considers the LCH corresponding to the DRB for which SDT is acceptable. If data is available for transmission to a DRB other than the DRB for which SDT is acceptable, the UE must initiate connection reactivation without SDT. In one embodiment, condition 5 is not used to determine the SDT.

[0202] Condition 6: UE has a valid TA value.

[0203] The network sets the SDT-TimeAlignmentTimer. The SDT-TimeAlignmentTimer starts when it receives the SDT-TimeAlignmentTimer setting from the network. The SDT-TimeAlignmentTimer starts again when a timing advance instruction MAC control element is received or when PDCCH indicates a timing advance adjustment.

[0204] *If SDT-TimeAlignmentTimer is running; and

[0205] * The SS-RSRP (which is the linear average of the power contributions of the resource elements that return the secondary synchronization signal to the SS reference signal received power) of the path loss criterion (i.e., SSB) does not increase by more than rsrp-IncreaseThresh after the last SDT-TimeAlignmentTimer has started; and

[0206] *If the SS-RSRP of the path loss criterion (i.e., SSB) does not decrease by more than rsrp-DecreaseThresh after the last SDT-TimeAlignmentTimer has started,

[0207] **A TA is considered valid. An SSB for which SS-RSRP is measured for TA validation is either one of the SSBs sent in a camped cell, or one of the SSBs associated with a pre-configured PUSCH resource, or one of the SSBs associated with a pre-configured PUSCH resource and sent in a camped cell. If several such SSBs exist, the SS-RSRP of the best SSB among them (i.e., the one with the highest SS-RSRP value) can be used for TA validation.

[0208] Condition 7: The UE has at least one SSB associated with the pre-configured PUSCH resource for the UL carrier / UL BWP selected for SDT using the pre-configured PUSCH resource that has an SS-RSRP higher than the critical value. If the RSRP based on downlink path loss is less than rsrp-ThresholdSSB-SUL, SUL is selected for SDT using the pre-configured PUSCH resource. Otherwise, NUL is selected for SDT using the pre-configured PUSCH resource. In one embodiment, Condition 7 is not used to determine SDT.

[0209] Condition 8: If the size of the MAC PDU being transmitted is less than or equal to the transport block size (TBS) of the pre-configured PUSCH resource, or if the size of the available data is less than or equal to the data volume critical value (the data volume critical value is signaled by the gNB), one of the following options can be used to set the TBS for the SDT using the pre-configured PUSCH resource and to decide whether to use the pre-configured PUSCH resource for small data transmission or to use general connection resumption.

[0210] Example 2-2-1 - Option 1: Single PUSCH setting and no signal quality-based critical value (for UL carrier of camped cells)

[0211] gNB sets a single PUSCH setting for SDT (for the UL carrier of the camped cell). TBS is not explicitly signaled and is determined based on the number of SCS, PRBs and OFDM symbols of the PUSCH resource. TBS can also be explicitly signaled.

[0212] - If the message size (UL data available for transmission + MAC header and MAC control elements if necessary) is smaller than the TB size of the payload by the PUSCH setting on the UL carrier selected for transmission,

[0213] *The UE starts sending small data using a pre-configured PUSCH resource.

[0214] -Others

[0215] *The UE will not initiate small data transmission using a pre-configured PUSCH resource. The UE may initiate small data transmission using RACH if the RACH-based criteria for performing SDT are met.

[0216] Example 2-2-2 - Option 2: Single PUSCH setting and single RSRP critical value (for UL carrier of camped cell)

[0217] The gNB sets a single PUSCH setting for SDT (for the UL carrier of camped cells). The TBS is not explicitly signaled and is determined based on the number of SCS, PRBs and OFDM symbols of the PUSCH resource. The TBS can also be explicitly signaled. The gNB also sets the parameter sdt-Threshold. Such parameters are set separately for SUL and NUL because their UL coverage differs.

[0218] - If the message size (UL data available for transmission + MAC header and MAC control elements if necessary) is less than or equal to the TB size of the payload based on the PUSCH settings on the UL carrier selected for transmission, and the RSRP based on downlink path loss is greater than or equal to the sdt-Threshold,

[0219] *The UE starts sending small data using a pre-configured PUSCH resource.

[0220] -Others

[0221] *The UE will not initiate small data transmission using a pre-configured PUSCH resource. The UE may initiate small data transmission using RACH if the RACH-based criteria for performing SDT are met.

[0222] Example 2-2-3 - Option 3: Multiplexing [PUSCH setting, critical value]

[0223] gNB sets the PUSCH-Config-SDT-1 and PUSCH-Config-SDT-2 parameters for SDT (for the UL carrier of camped cells). TBS is not explicitly signaled and is determined based on the number of SCS, PRBs and OFDM symbols of the PUSCH resource. TBS can also be explicitly signaled. sdt-Threshold-1 is also set. Such parameters are set separately for SUL and NUL due to the different UL coverage for SUL and NUL.

[0224] - If the size of the message (UL data available for transmission + MAC header and MAC control elements if necessary) is less than or equal to the TB size of the payload by PUSCH-Config-SDT-1 to SDT on the UL carrier selected for transmission,

[0225] *The UE starts sending small data using the PUSCH resources pre-configured in PUSCH-Config-SDT-1.

[0226] -In addition, if the message size (UL data + MAC header and MAC control elements if necessary, available for transmission) is less than or equal to the TB size of the payload by PUSCH-Config-SDT-2 on the selected UL carrier, and the RSRP based on downlink path loss is greater than or equal to sdt-Threshold-2,

[0227] *UE starts sending small data using the PUSCH resources pre-configured in PUSCH-Config-SDT-2.

[0228] -Others

[0229] *The UE will not initiate small data transmission using a pre-configured PUSCH resource. The UE may initiate small data transmission using RACH if the RACH-based criteria for performing SDT are met.

[0230] This option can be generalized by gNB setting the parameters PUSCH-Config-SDT-1~PUSCH-Config-SDT-N;sdt-Threshold-2~sdt-Threshold-N.

[0231] - If the size of the message (UL data available for transmission + MAC header and MAC control elements if necessary) is less than or equal to the TB size of the payload by PUSCH-Config-SDT-1 to SDT on the UL carrier selected for transmission,

[0232] *The UE starts sending small data using the PUSCH resources pre-configured in PUSCH-Config-SDT-1.

[0233] -In addition, if the message size (UL data + MAC header and MAC control elements if necessary, available for transmission) is less than or equal to the TB size of the payload by PUSCH-Config-SDT-2 for the selected UL carrier, and the RSRP for downlink path loss criteria is greater than or equal to sdt-Threshold-2,

[0234] *UE starts sending small data using the PUSCH resources pre-configured in PUSCH-Config-SDT-2.

[0235] -In addition, if the message size (UL data + MAC header and MAC control elements if necessary, available for transmission) is greater than the payload TB size by PUSCH-Config-SDT-2 (the phrase "greater than the payload TB size by PUSCH-Config-SDT-2" can be removed in one embodiment), less than or equal to the payload TB size by PUSCH-Config-SDT-3 for SDT on the UL carrier selected for transmission, and the RSRP based on downlink path loss is greater than or equal to sdt-Threshold-3,

[0236] *UE starts sending small data using the PUSCH resources pre-configured in PUSCH-Config-SDT-2.

[0237] -In addition, if the message size (UL data + MAC header and MAC control elements if necessary, available for transmission) is greater than the TB size of the payload by PUSCH-Config-SDT-N-1 (the phrase "greater than the TB size of the payload by PUSCH-Config-SDT-N-1" can be removed in one embodiment), and is less than or equal to the TB size of the payload by PUSCH-Config-SDT-N for SDT on the UL carrier selected for transmission, and the RSRP based on downlink path loss is greater than or equal to sdt-Threshold-N,

[0238] *UE starts sending small data using the PUSCH resources pre-configured in PUSCH-Config-SDT-N.

[0239] -Others

[0240] *The UE will not initiate small data transmission using a pre-configured PUSCH resource. The UE may initiate small data transmission using RACH if the RACH-based criteria for performing SDT are met.

[0241] Example 2-2-3A - Option 3A

[0242] gNB sets parameters PUSCH-Config-SDT-1 and PUSCH-Config-SDT-2 in the PUSCH settings for SDT (for the UL carrier of camped cells). TBS is not explicitly signaled and is determined based on the number of SCS, PRBs and OFDM symbols of the PUSCH resource. TBS can also be explicitly signaled. sdt-Threshold-1 and sdt-Threshold-2 are also set. Such parameters are set separately for SUL and NUL due to the different UL coverage for SUL and NUL.

[0243] - If the message size (UL data available for transmission + MAC header and MAC control elements if necessary) is less than or equal to the TB size of the payload by PUSCH-Config-SDT-1 for SDT on the UL carrier selected for transmission, and the RSRP based on downlink path loss is greater than or equal to sdt-Threshold-1,

[0244] *The UE starts sending small data using the PUSCH resources pre-configured in PUSCH-Config-SDT-1.

[0245] -In addition, if the message size (UL data + MAC header and MAC control elements if necessary, available for transmission) is greater than the payload TB size by PUSCH-Config-SDT-1 (the phrase "greater than the payload TB size by PUSCH-Config-SDT-1" can be removed in one embodiment), less than or equal to the payload TB size by PUSCH-Config-SDT-2 for the selected UL carrier, and the RSRP for downlink path loss criteria is greater than or equal to sdt-Threshold-2,

[0246] *UE starts sending small data using the PUSCH resources pre-configured in PUSCH-Config-SDT-2.

[0247] -Others

[0248] *The UE will not initiate small data transmission using a pre-configured PUSCH resource. The UE may initiate small data transmission using RACH if the RACH-based criteria for performing SDT are met.

[0249] This option can be generalized by gNB setting the parameters PUSCH-Config-SDT-1~PUSCH-Config-SDT-N;sdt-Threshold-1~sdt-Threshold-N.

[0250] - If the message size (UL data available for transmission + MAC header and MAC control elements if necessary) is less than or equal to the TB size of the payload by PUSCH-Config-SDT-1 for SDT on the UL carrier selected for transmission, and the RSRP based on downlink path loss is greater than or equal to sdt-Threshold-1,

[0251] *The UE starts sending small data using the PUSCH resources pre-configured in PUSCH-Config-SDT-1.

[0252] -In addition, if the message size (UL data + MAC header and MAC control elements if necessary, available for transmission) is greater than the payload TB size by PUSCH-Config-SDT-1 (the phrase "greater than the payload TB size by PUSCH-Config-SDT-1" can be removed in one embodiment), less than or equal to the payload TB size by PUSCH-Config-SDT-2 for the selected UL carrier, and the RSRP for downlink path loss criteria is greater than or equal to sdt-Threshold-2,

[0253] *UE starts sending small data using the PUSCH resources pre-configured in PUSCH-Config-SDT-2.

[0254] -In addition, if the message size (UL data + MAC header and MAC control elements if necessary, available for transmission) is greater than the TB size of the payload by PUSCH-Config-SDT-N-1 (the phrase "greater than the TB size of the payload by PUSCH-Config-SDT-N-1" can be removed in one embodiment), and is less than or equal to the TB size of the payload by PUSCH-Config-SDT-N for SDT on the UL carrier selected for transmission, and the RSRP based on downlink path loss is greater than or equal to sdt-Threshold-N,

[0255] *UE starts sending small data using the PUSCH resources pre-configured in PUSCH-Config-SDT-N.

[0256] -Others

[0257] *The UE will not initiate small data transmission using a pre-configured PUSCH resource. The UE may initiate small data transmission using RACH if the RACH-based criteria for performing SDT are met.

[0258] Example 2-2-4 - Option 4: Multiple [TBS]

[0259] gNB sets parameters PUSCH-Config-SDT-1 and PUSCH-Config-SDT-2 in the PUSCH settings for SDT (for the UL carrier of camped cells). TBS is not explicitly signaled and is determined based on the number of SCS, PRBs and OFDM symbols of the PUSCH resource. TBS can also be explicitly signaled. Such parameters are set separately for SUL and NUL due to the different UL coverage for SUL and NUL.

[0260] - If the message size (UL data available for transmission + MAC header and MAC control elements if necessary) is less than or equal to the payload size TB by PUSCH-Config-SDT-1,

[0261] *The UE starts sending small data using the PUSCH resources pre-configured in PUSCH-Config-SDT-1.

[0262] -In addition, if the message size (UL data available for transmission + MAC header and MAC control elements if necessary) is less than or equal to the payload TB size according to PUSCH-Config-SDT-2,

[0263] *UE starts sending small data using the PUSCH resources pre-configured in PUSCH-Config-SDT-2.

[0264] -Others

[0265] *The UE will not initiate small data transmission using a pre-configured PUSCH resource. The UE may initiate small data transmission using RACH if the RACH-based criteria for performing SDT are met.

[0266] This option can be generalized by gNB setting parameters PUSCH-Config-SDT-1 to PUSCH-Config-SDT-N.

[0267] - If the message size (UL data available for transmission + MAC header and MAC control elements if necessary) is less than or equal to the payload size TB by PUSCH-Config-SDT-1,

[0268] *The UE starts sending small data using the PUSCH resources pre-configured in PUSCH-Config-SDT-1.

[0269] -In addition, if the message size (UL data available for transmission + MAC header and MAC control elements if necessary) is less than or equal to the payload TB size according to PUSCH-Config-SDT-2,

[0270] *UE starts sending small data using the PUSCH resources pre-configured in PUSCH-Config-SDT-2.

[0271] -In addition, if the message size (UL data available for transmission + MAC header and MAC control elements if necessary) is less than or equal to the payload TB size according to PUSCH-Config-SDT-3,

[0272] *UE starts sending small data using the PUSCH resources pre-configured in PUSCH-Config-SDT-3.

[0273] -In addition, if the message size (UL data available for transmission + MAC header and MAC control elements if necessary) is less than or equal to the TB size of the payload by PUSCH-Config-SDT-N,

[0274] *UE starts sending small data using the PUSCH resources pre-configured in PUSCH-Config-SDT-N.

[0275] -Others

[0276] *The UE will not initiate small data transmission using a pre-configured PUSCH resource. The UE may initiate small data transmission using RACH if the RACH-based criteria for performing SDT are met.

[0277] Example 2-3 - PDCCH monitoring when sending small data using a pre-configured PUSCH resource

[0278] When transmitting uplink data using a pre-configured PUSCH resource, the UE needs to monitor the PDCCH for network responses.

[0279] Search Space: The UE needs to know the search space for monitoring the PDCCH. One of the following options can be used to determine the search space for monitoring the PDCCH for network responses to SDT using the pre-configured PUSCH resource.

[0280] - Option 1: The sdt-SearchSpaceCG for SDT using the pre-configured PUSCH resource can be signaled by the network in the RRCRlease message together with the pre-configured PUSCH resource.

[0281] *1-1: The sdt-SearchSpaceCG indicates one of the search spaces in the PDCCH-ConfigCommon IE of the initial DL BWP or DL BWP that has the same BWP ID as the UL BWP selected for SDT using the pre-configured PUSCH resource.

[0282] *1-2: The sdt-SearchSpaceCG indicates one of the search spaces in the PDCCH-Config IE of the initial DL BWP or DL BWP that has the same BWP ID as the UL BWP selected for SDT using the pre-configured PUSCH resource.

[0283] - Option 2: The sdt-SearchSpaceCG can be signaled by the network in the initial DL BWP configuration (PDCCH-ConfigCommon IE or PDCCH-Config IE) or DL BWP configuration that has the same BWP ID as the UL BWP selected for SDT using the pre-configured PUSCH resource.

[0284] -sdt-SearchSpaceCG indicates the search space ID of the search space setting (from the list of search space settings) used for PDCCH monitoring.

[0285] -UE monitors the search space using an RX beam corresponding to the SSB associated with the UL grant transmitted by the UE.

[0286] RNTI:UE needs to know the RNTI in order to monitor PDCCH. The UE can monitor PDCCH addressed to C-RNTI, where C-RNTI is used in the cell that received the pre-configured PUSCH resource. Alternatively, C-RNTI can be assigned along with the pre-configured PUSCH resource (for example, in an RRCRlease message).

[0287] Monitoring Time: The UE needs to know the time interval for monitoring responses. The timer can be set by the network along with a pre-configured PUSCH resource. The timer can be started at the end of a PUSCH transmission, at the first PDCCH monitoring occasion at the end of a PUSCH transmission, or at a fixed offset at the end of a PUSCH transmission. The timer is terminated when the UE receives a PDCCH addressed to C-RNTI and the TB is successfully decoded.

[0288] Retransmission process:

[0289] - Option 1: Do not retransmit. Once the timer expires, the SDT is considered to have failed.

[0290] -Option 2: Timer-based retransmission: If the UE has not yet sent the configurable number of MAC PDUs, it will retransmit the MAC PDU generated using a pre-configured PUSCH resource. Once the UE has sent the configurable number of MAC PDUs, the SDT is considered to have failed.

[0291] *During a retransmission, the UE first selects an SSB (in one embodiment, the UE uses the same SSB that was selected during the first transmission); then the UE selects a PUSCH resource corresponding to the selected SSB; then the UE transmits using the selected PUSCH resource; and the UE starts a monitoring timer and waits for a response (i.e., a PDCCH addressed to C-RNTI). If UCI is supported, the UE can indicate a new transmission / retransmission with UCI. A Redundancy Version (RV) can be predefined for each transmission / retransmission.

[0292] *During retransmission, power ramping for push transmission may be performed. Power from the previous transmission may be ramped by the power ramping phase. The power ramping phase is signaled by gNB.

[0293] -Option 3: Network-triggered retransmission:

[0294] *When a UE receives a PDCCH addressed to C-RNTI for HARQ retransmission of a HARQ process used for SDT with a pre-configured PUSCH resource, the UE performs HARQ retransmission. The PDCCH indicates a UL grant for retransmission. The HARQ process used for SDT with a pre-configured PUSCH resource can be signaled in the SDT configuration or predefined.

[0295] *The UE restarts the monitoring timer and waits for a response.

[0296] *The UE continues to use the SSB selected during the initial transmission.

[0297] During retransmission, power ramping for PUSCH transmission can be performed. The power of the previous transmission can be ramped by the power ramping stage. The power ramping stage is signaled by the gNB.

[0298] As a response to small data transmission, the UE can receive a signal (RRC message or DCI) for the following purposes.

[0299] Release a preset PUSCH or switch to a resume procedure (i.e., RRC_CONNECTED).

[0300] Example 2-4 - Release of Preset PUSCH Resources

[0301] Option 1: Timer-Based Release

[0302] - The timer starts (again) when receiving a preset PUSCH resource in a release message. If the timer expires, the preset PUSCH resource is released.

[0303] Option 2: Release by Number of Occurrences

[0304] - The MAC entity must discard the preset PUSCH resource immediately after "N" consecutive relevant periods in which the grant is not used. The relevant period is equal to the period of the set grant * X, where X is the number of SSBs associated with the set grant.

[0305] Option 3: Receiving an RRCRlease without any indication of using any preset PUSCH resource or previously set resource

[0306] Option 4: Release When Cell Changes

[0307] Option 5: Release When Connection Resumes

[0308] Option 6: The gNB may want to release the pre-configured PUSCH for inactive UEs. RAN paging can then be used. A new field may be introduced in the RAN paging. When the UE receives the RAN paging with the new field, it releases the pre-configured PUSCH but does not need to switch to RRC_CONNECTED.

[0309] Example 2-5 - Signaling flow without context fetching

[0310] Figure 4 shows a flowchart for transmitting small data using a pre-configured uplink resource according to one embodiment of the present disclosure.

[0311] Referring to Figure 4, in this case, we assume that the gNB has the context of the UE.

[0312] 0. The criteria for starting SDT using pre-configured PUSCH resources are met.

[0313] 1. The UE, using a pre-configured PUSCH resource, sends an RRCResumeRequest / RRCResumeRequest1 on SRB0 to the gNB (identical to the last serving gNB) in operation 410. The request includes a full / short I-RNTI (resumeIdentity), a resumeCause, and an authentication token (resumeMAC-I). The I-RNTI (short or full I-RNTI) is used for context identification, and its value must be identical to the I-RNTI received by the UE from the last serving gNB in ​​the RRCRlease with the suspendConfig message. The ResumeMAC-I is a 16-bit message authentication token, which the UE must calculate using an integrity algorithm (NIA or EIA) in a stored AS security context negotiated between the UE and the last serving gNB, and a KRRCint from the stored AS security context with the following inputs:

[0314] -KEY: Must be set to the current KRRCint;

[0315] -BEARER: All bits must be set to 1;

[0316] -DIRECTION: must be set to 1;

[0317] -COUNT: All bits must be set to 1;

[0318] -MESSAGE: VarResumeMAC-Input must be set to have the following input:

[0319] -Source PCI(UE is set to the physical cell identity of the connected PCIe before the RRC connection is interrupted);

[0320] -Target cell ID (the cellIdentity of the first PLMN-Identity included in the PLMN-IdentityInfoList broadcast in the target cell's SIB1, i.e., set to the cell from which the UE is sending small data); and

[0321] - Source C-RNTI (The UE is set to the C-RNTI that was on the PCell it was connected to before the RRC connection was interrupted).

[0322] The UE restarts all SRBs and DRBs, derives a new security key using the NextHopChainingCount provided in the RRCRlease message for the previous RRC connection, and resets the AS security. User data is encrypted and integrity protected (only for DRBs with UP integrity protection enabled) and sent over the DTCH multiplexed with RRCResumeRequest / RRCResumeRequest1 messages over the CCCH.

[0323] Alternatively, the UE can send small data by using one of the following options:

[0324] -RRCResumeRequest (or a new RRC message). ResumeIdentity, ResumeMAC-I, resumeCause, NAS container for RRCResumeRequest / RRCResumeRequest1. The NAS container contains UL data.

[0325] - New MAC CE (resumeIdentity, ResumeMAC-I) + uplink data (on DTCH). resumeIdentity is provided for UE identification. ResumeMAC-I is for security purposes.

[0326] 2. The gNB verifies resumeMAC-I in operation 420 and transmits uplink data to the UPF.

[0327] 3. The gNB sends an RRCRlease message to keep the UE in the RRC_INACTIVE state. The PDCCH is addressed to the C-RNTI, which is used in the cell where the UE received a pre-configured PUSCH resource. Alternatively, the C-RNTI can be assigned along with a pre-configured PUSCH resource. If downlink data is available in operation 430, the downlink data is encrypted and transmitted with integrity protection on the DTCH, which is multiplexed with the RRCRlease message on the DCCH in operation 440 (only for DRBs with UP integrity protection enabled).

[0328] (Alternative 1) The gNB considers an alternative signaling flow in which it can schedule a UL grant (PDCCH addressed to C-RNTI) before RRCRlease. In UL transmission, the UE can indicate if there is any more data to transmit. If there is any more data to transmit, the gNB can schedule a UL grant. Otherwise, it schedules an RRCRlease. In UL transmission, the UE can also include an SSB ID of a higher-than-critical SSB if the SSB indicated by the PRACH preamble is no longer suitable.

[0329] (Alternative 2) As an alternative, the gNB can send a PDCCH addressed to the RNTI (i.e., the RNTI is allocated by the gNB along with a pre-configured resource, and the RNTI can also be allocated to other UEs), and the scheduled DL TB includes the competition resolution identity (which is the first X bits (e.g., 48 bits) of the restart message) and the C-RNTI. If this matches the UE's competition resolution identity, the UE can abort the monitoring timer and consider the small data transmission successful.

[0330] In response to a small data transmission, the UE may receive signals (RRC messages or DCI) for purposes such as:

[0331] Either release the pre-configured PUSCH command or switch to the restart procedure (i.e., RRC_CONNECTED).

[0332] Example 2-6 - Exemplary signaling flow using context fetching and route rerouting

[0333] Figure 5 is a flowchart for transmitting small data using pre-configured uplink resources according to an embodiment of the present disclosure.

[0334] Referring to Figure 5, in this case, we assume that the gNB does not have the UE's context and fetches the same context from the last serving gNB. A route rerouting occurs, and the context is removed from the last serving gNB. This can only happen if the UE sends using a pre-configured PUSCH resource in a different cell from the cell where it last received the RRC deactivation message.

[0335] 0. The criteria for starting SDT using pre-configured PUSCH resources are met.

[0336] 1. The UE, using a pre-configured PUSCH resource, sends an RRCResumeRequest / RRCResumeRequest1 on SRB0 to a gNB (different from the last serving gNB) in operation 510. The request includes the full / short I-RNTI (resumeIdentity), the resume cause (resumeCause), and the authentication token (resumeMAC-I). The I-RNTI (short or full I-RNTI) is used for context identification, and its value must be identical to the I-RNTI received by the UE from the last serving gNB in ​​the RRCRlease with the suspendConfig message. The ResumeMAC-I is a 16-bit message authentication token. The UE must compute the ResumeMAC-I using the integrity algorithm (NIA or EIA) in the stored AS security context negotiated between the UE and the last serving gNB, and a KRRCint from the stored AS security context with the following inputs:

[0337] -KEY: Must be set to the current KRRCint;

[0338] -BEARER: All bits must be set to 1;

[0339] -DIRECTION: must be set to 1;

[0340] -COUNT: All bits must be set to 1;

[0341] -MESSAGE: VarResumeMAC-Input must be set to have the following input:

[0342] -Source PCI(UE is set to the physical cell identity of the connected PCIe before the RRC connection is interrupted);

[0343] -Target cell ID (the cellIdentity of the first PLMN-Identity included in the PLMN-IdentityInfoList broadcast in the target cell's SIB1, i.e., set to the cell that the UE is trying to restart); and

[0344] - Source C-RNTI (The UE is set to the C-RNTI that was on the PCell it was connected to before the RRC connection was interrupted).

[0345] The UE restarts all SRBs and DRBs, derives a new security key using the NextHopChainingCount provided in the RRCConnectionRelease message of the previous RRC connection, and resets the AS security. User data is encrypted, integrity protected (only for DRBs with UP integrity protection enabled), and sent over the DTCH multiplexed with RRCResumeRequest / RRCResumeRequest1 messages over the CCCH.

[0346] 2. The gNB (i.e., the target gNB) identifies the gNB identity of the last serving gNB (i.e., the source gNB) from the I-RNTI and requests the last serving gNB to provide context data for the UE by sending a Retrieve UE Context Request message containing the I-RNTI, ResumeMAC-I, and target Cell-ID, so that the source gNB can verify the UE request and retrieve the UE context.

[0347] 3. The last serving gNB (i.e., source gNB) validates resumeMAC-I and provides UE context data.

[0348] The source gNB uses I-RNTI to search the database for stored UE contexts that include the UE 5G AS security context. The source gNB then retrieves the current K stored in the retrieved UE 5G AS security context. RRCint The ResumeMAC-I is verified using the key (the ResumeMAC-I is calculated using the same method as described above). If the verification of the ResumeMAC-I is successful, the source gNB is determined using horizontal key derivation or vertical key derivation based on whether the source gNB has unused pairs of {NCC, NH}, using the target cell PCI, target ARFCN-DL, and KgNB / NH in the current UE 5G AS security context. NG-RAN * is calculated. The source gNB can obtain the target PCI and target ARFCN-DL from the cell configuration database via the target Cell-ID received from the target gNB. The source gNB must then respond with an Xn-AP Retrieve UE Context Response message to the target Gnb in operation 520, which includes the UE 5G AS security context. The UE 5G AS security context sent to the target gNB is the newly derived K NG-RAN *, K NG-RAN *This must include the NCC, UE 5G security capabilities, UP security policy, UP security activation state with corresponding PDU session ID, and encryption and integrity algorithms used by the UE together with the source cell.

[0349] 4. If loss of buffered DL user data in the last serving gNB must be prevented, the gNB provides a forwarding address in operation 525.

[0350] 5. gNB performs route switching in operations 530 and 535.

[0351] 6. gNB triggers the release of the UE resource in operation 540, which is the last serving gNB.

[0352] 7. The gNB transmits uplink data to the UPF in operation 545.

[0353] 8. The gNB sends an RRCRlease message to keep the UE in the RRC_INACTIVE state. The PDCCH is addressed to the C-RNTI, which is the cell used when the UE receives a pre-configured PUSCH resource. Alternatively, the C-RNTI can be assigned along with a pre-configured PUSCH resource. If downlink data is available in operation 550, the downlink data is encrypted and transmitted with integrity protection over the DTCH (only for DRBs with UP integrity protection enabled) which is multiplexed with the RRCRlease message on the DCCH in operation 555.

[0354] (Alternative 1) The gNB may consider an alternative signaling flow that allows scheduling a UL grant (PDCCH addressed to C-RNTI) before RRCRlease. In UL transmission, the UE may indicate if there is any more data to transmit. If there is more data to transmit, the gNB may schedule a UL grant. Otherwise, it schedules an RRCRlease. In UL transmission, the UE may also include an SSB ID of a higher-than-critical SSB if the SSB indicated by the PRACH preamble is no longer suitable.

[0355] (Alternative 2) As an alternative, the gNB can send a PDCCH addressed to the RNTI (i.e., the RNTI is allocated by the gNB along with a pre-configured resource, which can also be allocated to other UEs), and the scheduled DL TB includes the competition resolution identity (which is the first X bits (e.g., 48 bits) of the restart message) and the C-RNTI. If this matches the UE's competition resolution identity, the UE can abort the monitoring timer and consider the small data transmission successful.

[0356] In response to a small data transmission, the UE may receive signals (RRC messages or DCI) for purposes such as:

[0357] Either release the pre-configured PUSCH command or switch to the restart procedure (i.e., RRC_CONNECTED).

[0358] Example 2-7 - MAC PDU generation for SDT

[0359] In one method of this disclosure, none of the LCH restrictions apply while generating the MAC PDU for small data transmission in RRC_INACTIVE using MsgA or Msg3 or a pre-configured PUSCH resource.

[0360] Figure 6 shows a flowchart for generating a MAC (medium access control) protocol data unit (PDU) for small data transmission according to one embodiment of the present disclosure.

[0361] Referring to Figure 6, if a UL grant for a new transmission is available in operation 610, operation 620 determines whether such a UL grant is for an SDT. If the UL grant is for an SDT, the UE selects all logical channels for MAC PDU generation (i.e., logical channels corresponding to the RBs that are restarted when the small data transmission procedure is initiated) in operation 640 and applies the LCP procedure to the selected logical channels in operation 650. Otherwise, in operation 630, the UE selects logical channels (from among the logical channels corresponding to the RBs that are restarted when the small data transmission procedure is initiated) that are allowed to be transmitted with such a UL grant, by at least one of allowedSCS-List, maxPUSCH-Duration, configuredGrantType1Allowed, allowedServingCells, allowedCG-List, or allowedPHY-PriorityIndex for MAC PDU generation.

[0362] Figure 7 shows a flowchart illustrating the generation of a MAC PDU for small data transmission according to one embodiment of the present disclosure.

[0363] Referring to Figure 7, allowedSCS-List and maxPUSCH-Duration are applied to generate MAC PDUs for SDT. This means that if allowedSCS-List is set to LCH and the SCS included in allowedSCS-List is not the SCS of the UL grant used for SDT, such an LCH will not be selected for SDT. This means that if maxPUSCH-Duration is set to LCH and the duration included in allowedSCS-List is not the duration of the UL grant used for SDT, such an LCH will not be selected for SDT. AllowedServingCells is not applied to generate MAC PDUs for SDT. ConfiguredGrantType1Allowed is not applied for RACH-based small data transmissions, but is allowed for non-RACH-based small data transmissions. For non-RACH-based small data transmissions, if configureGrantType1Allowed is not set to LCH, such an LCH will not be selected for SDT.

[0364] Specifically, if an UL grant for a new transmission is available in operation 710, operation 720 determines whether such an UL grant is for an SDT. If the UL grant is not for an SDT, in operation 730 the UE selects a logical channel that is allowed to be transmitted with such an UL grant by allowedSCS-List, maxPUSCH-Duration, configureGrantType1Allowed, allowedServingCells, allowedCG-List, and allowedPHY-PriorityIndex for MAC PDU generation. Otherwise, in operation 740 the UE determines whether the UL grant is a pre-configured UL grant. If the UL grant is a pre-configured UL grant, in operation 770 the UE selects a logical channel (from among the logical channels corresponding to the RB that will be restarted when the small data transmission procedure is initiated) that is allowed to be transmitted with such an UL grant by allowedSCS-List, maxPUSCH-Duration, and configuredGrantType1Allowed, and in operation 760 the LCP procedure is applied to the selected logical channel. If the UL grant is not a pre-configured UL grant, the UE selects a logical channel in operation 750, by allowedSCS-List and maxPUSCH-Duration, that is permitted to be transmitted on such a UL grant (from among the logical channels corresponding to the RB that will be restarted when the small data transmission procedure is initiated), and in operation 760, applies the LCP procedure to the selected logical channel.

[0365] In one method of this disclosure, the network indicates whether or not to apply LCH limits. The indication can be an RRCRlease or RACH setting for the SDT. If the network indicates to apply LCH limits, all LCH limits are considered when selecting an LCH for the SDT. In one embodiment, the limits that may be applied can also be indicated by the network. In this case, the UE applies only the LCH limits indicated when selecting an LCH for the SDT.

[0366] Figure 8 is a block diagram of a terminal according to one embodiment of the present disclosure.

[0367] Referring to Figure 8, the terminal includes a transceiver 810, a control unit 820, and a memory 830. The control unit 820 may refer to a circuit, an ASIC (application-specific integrated circuit), or at least one processor. The transceiver 810, the control unit 820, and the memory 830 are configured to perform the operations of the terminal shown in Figures 1 to 7 or described above. Although the transceiver 810, the control unit 820, and the memory 830 are shown as separate entities, they can be implemented as a single entity, such as a single chip. Alternatively, the transceiver 810, the control unit 820, and the memory 830 can be electrically connected or coupled to each other.

[0368] The transceiver 810 can transmit signals to other network entities, such as a base station, and receive signals from the base station.

[0369] The control unit 820 can control the terminal to perform the functions according to one of the embodiments described above. For example, the control unit 820 can control the transceiver 810 and / or memory 830 to perform small data transmission and reception according to various embodiments of the present disclosure.

[0370] In one embodiment, the operation of the terminal can be implemented using a memory 830 that stores the corresponding program code. The terminal may be equipped with a memory 830 that stores program code to implement the desired operation. In order to perform the desired operation, the control unit 820 can read and execute the program code stored in the memory 830 by using at least one processor or CPU.

[0371] Figure 9 is a block diagram of a base station according to one embodiment of the present disclosure.

[0372] Referring to Figure 9, the base station includes a transceiver 910, a control unit 920, and a memory 930. The control unit 920 may refer to a circuit, an ASIC, or at least one processor. The transceiver 910, the control unit 920, and the memory 930 are configured to perform the UE operations shown in Figures 1 to 7 or described above. Although the transceiver 910, the control unit 920, and the memory 930 are shown as separate entities, they can be implemented as a single entity, such as a single chip. The transceiver 910, the control unit 920, and the memory 930 can be electrically connected or coupled to one another.

[0373] The transceiver 910 can transmit signals to other network entities, such as terminals, and receive signals from terminals.

[0374] The control unit 920 can control the base station to perform the functions according to one of the embodiments described above. For example, the control unit 920 can control the transceiver 910 and / or memory 930 to perform small data transmission and reception according to various embodiments of the present disclosure.

[0375] In one embodiment, the operation of the base station can be implemented using a memory 930 that stores the corresponding program code. The base station may be equipped with a memory 930 that stores program code to implement the desired operation. To perform the desired operation, the control unit 920 can read and execute the program code stored in the memory 930 using at least one processor or CPU.

[0376] While this disclosure has been illustrated and described with reference to various embodiments thereof, those skilled in the art will understand that various modifications of form and details may be made without departing from the spirit and scope of this disclosure, as defined by the appended claims and equivalents.

[0377] While this disclosure has been illustrated and described with reference to various embodiments thereof, those skilled in the art will understand that various modifications of form and details may be made without departing from the spirit and scope of this disclosure, as defined by the appended claims and equivalents. [Explanation of symbols]

[0378] 810 Transmitter / Receiver 820 Control Unit 830 memory 910 Transmitter / Receiver 920 Control Unit 930 memory

Claims

1. In a method performed by a terminal in a wireless communication system, The steps include receiving a radio resource control (RRC) release message from a base station, which includes information about at least one configured uplink resource for small data transmission (SDT), While the terminal is in an RRC inactive state, the steps include identifying an uplink carrier for the SDT from among the normal uplink (NUL) or supplementary uplink (SUL), The steps include identifying an SSB from among a plurality of synchronization signal blocks (SSBs) associated with at least one configured uplink resource for the SDT on the identified uplink carrier, A method comprising the step of transmitting uplink data to the base station based on a configured uplink resource associated with the identified SSB.

2. The information relating to the SDT for the at least one configured uplink resource includes a first configuration of at least one configured uplink resource for the NUL and a second configuration of at least one configured uplink resource for the SUL, The plurality of SSBs associated with at least one configured uplink resource for the SDT are identified based on information about one or more SSB indices associated with the configuration for the identified uplink carrier, or based on all SSBs received in the cell associated with the NUL and SUL. The method according to claim 1, characterized in that the information relating to one or more SSB indices associated with the settings for the identified uplink carrier is signaled by the RRC release message.

3. The process further includes receiving information from the base station regarding the setting of the PDCCH (physical downlink control channel) for the initial downlink bandwidth part (bandwidth part; BWP) of the identified uplink carrier, The information relating to the PDCCH setting includes information regarding the SDT search space for monitoring the PDCCH for the response to the uplink data, The RRC deactivation message further includes information about the radio network temporary identifier (RNTI) for the SDT, The method according to claim 1, characterized in that the PDCCH is addressed to the RNTI.

4. The uplink carrier is identified based on a critical value of the first reference signal received power (RSRP) associated with SUL selection. The method according to claim 1, characterized in that the SSB is identified based on a critical value of second reference signal received power (RSRP) related to SSB selection for the SDT set by the base station.

5. In a method performed by a base station in a wireless communication system, A step of sending a radio resource control (RRC) release message to a terminal containing information about at least one configured uplink resource for small data transmission (SDT), The process includes the step of receiving uplink data from the terminal on the uplink carrier for the SDT, based on a configured uplink resource associated with a synchronization signal block (SSB), while the terminal is in an RRC-inactive state. The SSB is one of a plurality of SSBs associated with at least one configured uplink resource for the SDT, A method characterized in that the uplink carrier is one of a normal uplink (NUL) or an additional uplink (SUL).

6. The process further includes transmitting to the terminal information regarding the PDCCH (physical downlink control channel) setting for the initial downlink bandwidth part (BWP) of the uplink carrier for the SDT, The information relating to the PDCCH setting includes information regarding the SDT search space for monitoring the PDCCH for the response to the uplink data, The RRC deactivation message further includes information about the radio network temporary identifier (RNTI) for the SDT, The method according to claim 5, characterized in that the PDCCH is addressed to the RNTI.

7. The information relating to the SDT for the at least one configured uplink resource includes a first configuration of the at least one configured uplink resource for the NUL and a second configuration of the at least one configured uplink resource for the SUL. The plurality of SSBs associated with at least one configured uplink resource for the SDT are identified based on information about one or more SSB indices associated with the configuration for the uplink carrier for the SDT, or on all SSBs transmitted within the cell associated with the NUL and SUL. The method according to claim 5, characterized in that the information relating to one or more SSB indices in relation to the setting for the uplink carrier for the SDT is signaled by the RRC release message.

8. In a terminal of a wireless communication system, Transmitter and receiver, Includes a control unit, and the control unit is The transceiver receives a radio resource control (RRC) release message from the base station via the transceiver, which includes information about at least one configured uplink resource for small data transmission (SDT). While the terminal is in an RRC inactive state, it identifies the uplink carrier for the SDT from among the normal uplink (NUL) or the supplementary uplink (SUL), On the identified uplink carrier, an SSB is identified from among a plurality of synchronization signal blocks (SSBs) associated with at least one configured uplink resource for the SDT, A terminal configured to transmit uplink data to the base station via the transceiver, based on the configured uplink resource associated with the identified SSB.

9. The information relating to the SDT for the at least one configured uplink resource includes a first configuration of the at least one configured uplink resource for the NUL and a second configuration of the at least one configured uplink resource for the SUL, The plurality of SSBs associated with at least one configured uplink resource for the SDT are identified based on information about one or more SSB indices associated with the configuration for the identified uplink carrier, or based on all SSBs received in the cell associated with the NUL and SUL. The terminal according to claim 8, characterized in that the information relating to one or more SSB indices associated with the settings for the identified uplink carrier is signaled by the RRC release message.

10. The control unit is configured to receive information from the base station via the transceiver regarding the PDCCH (physical downlink control channel) setting for the initial downlink bandwidth part (BWP) of the identified uplink carrier, The information relating to the PDCCH setting includes information regarding the SDT search space for monitoring the PDCCH for the response to the uplink data, The RRC deactivation message further includes information about the radio network temporary identifier (RNTI) for the SDT, The terminal according to claim 8, characterized in that the PDCCH is addressed to the RNTI.

11. The uplink carrier is identified based on a critical value of the first reference signal received power (RSRP) associated with SUL selection. The terminal according to claim 8, characterized in that the SSB is identified based on a critical value of second reference signal received power (RSRP) related to SSB selection for the SDT set by the base station.

12. In a base station of a wireless communication system, Transmitter and receiver, Includes a control unit, and the control unit is A radio resource control (RRC) release message, including information about at least one configured uplink resource for small data transmission (SDT), is transmitted to the terminal via the transceiver. While the terminal is in an RRC-inactive state, the uplink carrier for the SDT is configured to receive uplink data from the terminal via the transceiver, based on configured uplink resources associated with a plurality of synchronization signal blocks (SSBs). The SSB is one of the plurality of SSBs associated with at least one configured uplink resource for the SDT, A base station characterized in that the uplink carrier is one of either a normal uplink (NUL) or a supplementary uplink (SUL).

13. The base station according to claim 12, characterized in that the at least one configured uplink resource for the SDT includes a first configured uplink resource for the NUL and a second configured uplink resource for the SUL.

14. The control unit is configured to transmit to the terminal via the transceiver information regarding the PDCCH (physical downlink control channel) setting for the initial downlink bandwidth part (BWP) of the uplink carrier for the SDT, The information relating to the PDCCH setting includes information regarding the SDT search space for monitoring the PDCCH for the response to the uplink data, The RRC deactivation message further includes information about the radio network temporary identifier (RNTI) for the SDT, The base station according to claim 12, characterized in that the PDCCH is addressed to the RNTI.

15. The information relating to the SDT for the at least one configured uplink resource includes a first configuration of the at least one configured uplink resource for the NUL and a second configuration of the at least one configured uplink resource for the SUL. The plurality of SSBs associated with at least one configured uplink resource for the SDT are identified based on information about one or more SSB indices associated with the configuration for the uplink carrier for the SDT, or on all SSBs transmitted within the cell associated with the NUL and SUL. The base station according to claim 12, characterized in that the information relating to one or more SSB indices related to the setting for the uplink carrier for the SDT is signaled by the RRC release message.

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