Small data transmission in the Radio Resource Control (RRC) inactive state

Abstract

Some embodiments of the present invention provide a method for a user equipment (UE) to transmit uplink (UL) data associated with a specific radio bearer (RB). When in a radio resource control (RRC)_CONNECTED state, the UE receives an RRC release message from a base station (BS), the RRC release message including at least a configured grant (CG) configuration and a time alignment (TA) timer. Then, in response to receiving the RRC release message, the UE transitions to an RRC_INACTIVE state and starts or restarts the TA timer. After determining that a set of one or more criteria is met, when in the RRC_INACTIVE state, the UE transmits UL data via UL resources configured by the CG configuration, the set of criteria including at least a criterion for a running TA timer.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of and priority to U.S. Provisional Patent Application No. 63 / 014,648, filed on April 23, 2020, entitled “Method and Apparatus of Selection of UL Grant Type for Transmission in RRC Inactive State,” and having attorney docket number US81214 (hereinafter referred to as the “US81214 application”). The disclosure of the US81214 application is hereby incorporated by reference into this application in its entirety. Technical Field

[0003] The present disclosure relates generally to wireless communications, and more particularly, to small data transmission by a user equipment (UE) when the UE is in an RRC_INACTIVE state in a next generation wireless network. Background Art

[0004] With the tremendous growth in the number of connected devices and the rapid increase in user / network traffic, various efforts have been made to improve different aspects of wireless communications in next-generation wireless communication systems, such as the fifth-generation (5G) New Radio (NR), by increasing data rates, latency, reliability, and mobility. The 5G NR system is designed to provide flexibility and configurability to optimize network services and types, accommodating various use cases such as enhanced mobile broadband (eMBB), massive machine-type communications (mMTC), and ultra-reliable low-latency communications (URLLC).

[0005] In NR, a user equipment (UE) can operate in and transition between various radio resource control (RRC) states within the next generation radio access network (RAN). These different states include the RRC connected state, the RRC idle state, and a newly added state called the RRC inactive state. UEs with infrequent data transmission (e.g., periodic and / or aperiodic) are typically maintained by the network in the RRC inactive (also known as RRC_INACTIVE) state. Note that a UE in the RRC_INACTIVE state cannot transmit data and must restore the connection for any downlink (DL) data reception and / or uplink (UL) data transmission (e.g., move / transition to the RRC_CONNECTED state). Therefore, resource scheduling (and subsequent resource release) must be performed for each data transmission, regardless of how small and infrequent the data packets of each transmission are. This results in unnecessary power consumption and signaling overhead.

[0006] The signaling overhead caused by the transmission of small data packets in UEs in an inactive state can be a common problem, which can become a critical issue not only for network performance and efficiency, but also for the battery performance of the UEs as the number of UEs increases. In general, any device that must transmit intermittent small data packets can benefit from enabling small data transmission in the inactive state. To enable small data transmission in the inactive state, the Third Generation Partnership Project (3GPP) recently introduced some mechanisms that utilize, for example, 2-step and / or 4-step random access channel (RACH) procedures and / or configured grants (e.g., Type 1CG) in the inactive state. However, since these mechanisms have only been introduced recently, there is a need to further improve the transmission of small data when the UE is in the inactive state. Summary of the Invention

[0007] The present disclosure relates to small data transmission by a user equipment (UE) when the UE is in an RRC_INACTIVE state.

[0008] In a first aspect of the present application, a method for a user equipment (UE) to transmit uplink (UL) data associated with a specific radio bearer (RB) is provided. The method comprises: when in a radio resource control (RRC)_CONNECTED state, receiving an RRC release message from a base station (BS), the RRC release message including at least a configured grant (CG) configuration and a time alignment (TA) timer; in response to receiving the RRC release message, transitioning to an RRC_INACTIVE state; in response to receiving the RRC release message, starting or restarting the TA timer; and after determining that a set of one or more criteria is met, transmitting the UL data via an UL resource configured by the CG configuration when in the RRC_INACTIVE state, the set of criteria including at least a criterion for the running TA timer.

[0009] Implementations of the first aspect further include starting or restarting the TA timer in response to receiving an indication to update the timing advance from the BS when in the RRC_INACTIVE state.

[0010] Another implementation of the first aspect further includes initiating a random access (RA) procedure when it is determined that one of the set of criteria is not met.

[0011] In another embodiment of the first aspect, the set of criteria further includes a criterion that a data amount of the UL data is lower than a threshold.

[0012] Another implementation of the first aspect further includes initiating an RRC connection recovery process when the data amount of the UL data is higher than the threshold.

[0013] In another implementation of the first aspect, the data amount is determined based on a total amount of the UL data associated with the specific RB.

[0014] In another embodiment of the first aspect, the set of criteria further includes a criterion for a synchronization signal block (SSB) having a reference signal received power (RSRP) above a threshold.

[0015] In another embodiment of the first aspect, the set of criteria further includes a criterion for a specific timer that is running, and when the UE transmits the UL data via the UL resource, the specific timer is started or restarted.

[0016] In another embodiment of the first aspect, the specific RB is configured for small data transmission.

[0017] In another implementation of the first aspect, the RRC release message further includes an information element (IE) suspendConfig.

[0018] In a second aspect, a UE is provided, comprising one or more non-transitory computer-readable media having computer-executable instructions for transmitting uplink (UL) data associated with a specific radio bearer (RB); and at least one processor. The processor is coupled to the one or more non-transitory computer-readable media and configured to execute the computer-executable instructions to receive an RRC release message from a base station (BS) while in a radio resource control (RRC) connected state, the RRC release message including at least a configured grant (CG) configuration and a time alignment (TA) timer; in response to receiving the RRC release message, transition to an RRC_INACTIVE state; in response to receiving the RRC release message, start or restart the TA timer; and after determining that a set of one or more criteria are met, transmit the UL data via UL resources configured by the CG configuration while in the RRC_INACTIVE state, the set of criteria including at least a criterion for the running TA timer. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Various aspects of the present exemplary disclosure are best understood from the following detailed description when read with the accompanying drawings. For clarity of discussion, various features are not drawn to scale and the dimensions of the various features may be arbitrarily increased or reduced.

[0020] Figure 1 is a diagram illustrating a UE state machine and UE state transition according to an exemplary embodiment of the present application.

[0021] Figure 2A is a diagram illustrating a 2-step random access (RA) type RA procedure (eg, for small data transmission) according to an exemplary embodiment of the present application.

[0022] Figure 2B is a diagram illustrating a 4-step random access type RA procedure (eg, for small data transmission) according to an exemplary embodiment of the present application.

[0023] Figure 3 is a flowchart illustrating a method (or process) performed by a UE to transmit uplink (UL) data to a base station when the UE is in an RRC_INACTIVE state according to an exemplary embodiment of the present application.

[0024] Figure 4 A block diagram of a node for wireless communication according to an exemplary embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0025] The acronyms used in this application are defined below. Unless otherwise specified, the acronyms have the following meanings:

[0026] Full acronym

[0027] 3GPP Third Generation Partnership Project

[0028] 5GC 5G Core

[0029] ACK

[0030] AMF Access and Mobility Management Function

[0031] ARQ Automatic Repeat Request

[0032] AS access layer

[0033] BCCH Broadcast Control Channel

[0034] BCH Broadcast Channel

[0035] BFR beam failure recovery

[0036] BS Base Station

[0037] BSR Buffer Status Report

[0038] BWP Bandwidth Part

[0039] Carrier Aggregation (CA)

[0040] CBRA Contention-based random access

[0041] CFRA Contention-Free Random Access

[0042] CG Configuration Authorization

[0043] CM Connection Management

[0044] CN Core Network

[0045] C-RNTI Cell Radio Network Temporary Identifier

[0046] CS-RNTI Configured Scheduling Radio Network Temporary Identifier

[0047] CSI-RS Channel State Information Reference Signal

[0048] DCI Downlink Control Information

[0049] DL Downlink

[0050] DRB Data Radio Bearer

[0051] DRX Discontinuous Reception

[0052] HARQ Hybrid Automatic Repeat Request

[0053] IE Information Element

[0054] LCH Logical Channel

[0055] LCG Logical Channel Group

[0056] LCP Logical Channel Prioritization

[0057] MAC Media Access Control

[0058] MIB Master Information Block

[0059] MSG message

[0060] NAS Non-Access Stratum

[0061] NG-RAN Next Generation Radio Access Network

[0062] NR New Radio

[0063] NW Network

[0064] PCell Primary Cell

[0065] PCCH Paging Control Channel

[0066] PDCCH Physical Downlink Control Channel

[0067] PDCP Packet Data Convergence Protocol

[0068] PDU Protocol Data Unit

[0069] PRACH Physical Random Access Channel

[0070] PUCCH Physical Uplink Control Channel

[0071] PUSCH Physical Uplink Shared Channel

[0072] PLMN Public Land Mobile Network

[0073] QoS Quality of Service

[0074] RA Random Access

[0075] RACH Random Access Channel

[0076] RAN Radio Access Network

[0077] RB Radio Bearer

[0078] Rel version

[0079] RLC Radio Link Control

[0080] RNA RAN-based notification area

[0081] RNTI Radio Network Temporary Identifier

[0082] RRC Radio Resource Control

[0083] RSRP Reference Signal Received Power

[0084] SCell Secondary Cell

[0085] SCG Secondary Cell Group

[0086] SCS subcarrier spacing

[0087] SDT Small Data Transfer

[0088] SDU Service Data Unit

[0089] SFN System Frame Number

[0090] SI System Information

[0091] SIB System Information Block

[0092] SINR Signal-to-Noise-and-Interference Ratio

[0093] SLIV start and length indicator

[0094] SNPN Independently operated non-public network

[0095] SR Scheduling Request

[0096] SRB Signalling Radio Bearer

[0097] SSB Synchronous Signal Block

[0098] S-TMSI SAE-Temporary Mobile Subscriber Identity

[0099] SUL Supplementary Uplink

[0100] TA Timing Advance or Time Alignment

[0101] TAG Timing Advance Group

[0102] TS Technical Specification

[0103] UE User Equipment

[0104] UL Uplink

[0105] UPF user plane function

[0106] The following description includes specific information related to exemplary embodiments of the present disclosure. The drawings and their descriptions in this disclosure relate only to examples. However, the present disclosure is not limited to these exemplary embodiments. Those skilled in the art will recognize other variations and embodiments of the present disclosure. Unless otherwise indicated, identical or corresponding elements in the drawings may be represented by identical or corresponding reference numerals. Furthermore, the drawings and illustrations in this disclosure are generally not drawn to scale and are not intended to correspond to actual relative dimensions.

[0107] For the purpose of consistency and ease of understanding, similar features may be identified by the same numbers in the example figures (although not shown in some examples). However, features in different embodiments may differ in other aspects and therefore should not be limited to what is shown in the drawings.

[0108] As used herein, the phrases "in one embodiment," or "in some embodiments," may each refer to one or more of the same or different embodiments. The term "coupled" is defined as connected, whether directly or indirectly through intermediate components, and is not necessarily limited to physical connections. The term "comprising" when used means "including, but not necessarily limited to"; it specifically refers to the unrestricted membership in the combinations, groups, series, and equivalents so described. The expression "at least one of A, B, and C" or "at least one of: A, B, and C" means: "only A, or only B, or only C, or any combination of A, B, and C."

[0109] In addition, for the purpose of explanation and non-limiting, specific details such as functional entities, technologies, protocols, standards, etc. are set forth to provide an understanding of the described technology. In other instances, detailed descriptions of well-known methods, technologies, systems, architectures, etc. are omitted so as not to obscure the description with unnecessary detail.

[0110] Those skilled in the art will immediately recognize that any network function or algorithm described in this disclosure can be implemented by hardware, software, or a combination of software and hardware. The functions described may correspond to modules, which may be software, hardware, firmware, or any combination thereof. Software implementations may include computer-executable instructions stored on a computer-readable medium such as a memory or other type of storage device. For example, one or more microprocessors or general-purpose computers with communication processing capabilities may be programmed using corresponding executable instructions and perform the described network functions or algorithms. These microprocessors or general-purpose computers may be formed by application-specific integrated circuits (ASICs: Applications Specific Integrated Circuitry), programmable logic arrays, and / or using one or more digital signal processors (DSPs: Digital Signal Processors). Although several exemplary embodiments described in this specification are for software installed and executed on computer hardware, alternative exemplary embodiments implemented as firmware or hardware or a combination of hardware and software are also within the scope of this disclosure.

[0111] Computer-readable media include, but are not limited to, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory, compact disc read-only memory (CD-ROM), cassettes, magnetic tapes, disk storage, or any other equivalent medium capable of storing computer-readable instructions.

[0112] A radio communication network architecture (e.g., a Long Term Evolution (LTE) system, an LTE-Advanced (LTE-A) system, an LTE-Advanced Pro system, or a 5G NR radio access network (RAN)) typically includes at least one base station, at least one UE, and one or more optional network elements that provide a connection to the network. The UE communicates with the network (e.g., a core network (CN), an evolved packet core (EPC), an evolved universal terrestrial radio access network (E-UTRAN), an 5G core (5GC), or the Internet) through the RAN established by one or more base stations.

[0113] It should be noted that in this application, UE may include but is not limited to a mobile station, a mobile terminal or device, and a user communication radio terminal. For example, a UE may be a portable radio device, including but not limited to a mobile phone, a tablet computer, a wearable device, a sensor, a vehicle, or a personal digital assistant (PDA) with wireless communication capabilities. A UE is configured to receive signals over an air interface and transmit signals to one or more cells in a radio access network.

[0114] The base station may be configured to provide communication services according to at least one of the following radio access technologies (RATs): Worldwide Interoperability for Microwave Access (WiMAX), Global System for Mobile communications (GSM, commonly referred to as 2G), GSM Enhanced Data Rates for GSM Evolution (EDGE) Radio Access Network (GERAN), General Packet Radio Service (GPRS), Universal Mobile Telecommunications System (UMTS, commonly referred to as 3G) based on basic Wideband-Code Division Multiple Access (W-CDMA), High-Speed ​​Packet Access (HSPA), LTE, LTE-A, eLTE (evolved LTE, such as LTE connected to 5GC), NR (commonly referred to as 5G), and / or LTE-A Pro. However, the scope of the present application should not be limited to the aforementioned protocols.

[0115] A base station may include, but is not limited to, a Node B (NB) in UMTS, an evolved Node B (eNB) in LTE or LTE-A, a Radio Network Controller (RNC) in UMTS, a BS Controller (BSC) in GSM / GSM Enhanced Data rates for GSM Evolution (EDGE) RAN (GERAN), a Next Generation (NG)-eNB in ​​an Evolved Universal Terrestrial Radio Access (E-UTRA) BS connected to a 5GC, a Next Generation Node B (gNB) in a 5G-RAN, and any other device capable of controlling radio communications and managing radio resources within a cell. A BS may be connected via a radio interface to serve one or more UEs.

[0116] A base station is operable to provide radio coverage to a specific geographic area using multiple cells included in a RAN. A BS supports the operation of cells. Each cell is operable to provide services to at least one UE within its radio coverage. Specifically, each cell (often referred to as a serving cell) can provide services to serve one or more UEs within its radio coverage (e.g., each cell schedules downlink and optionally uplink resources to at least one UE within its radio coverage for downlink and optionally uplink packet transmission). A BS can communicate with one or more UEs in a radio communication system via multiple cells.

[0117] The cell can allocate sidelink (SL: Sidelink) resources to support proximity service (ProSe: Proximity Service) or vehicle to everything (V2X: Vehicle to Everything) service. Each cell may have a coverage area that overlaps with other cells. In the case of multi-RAT dual connectivity (MR-DC), the main cell of the main cell group (MCG: Master Cell Group) or the secondary cell group (SCG: Secondary Cell Group) may be called a special cell (SpCell: Special Cell). The main cell (PCell: Primary Cell) may refer to the SpCell of the MCG. The primary SCG cell (PSCell: Primary SCGCell) may refer to the SpCell of the SCG. MCG may refer to a service cell group associated with a master node (MN: Master Node), including SpCell and optionally one or more secondary cells (SCell). SCG may refer to a service cell group associated with a secondary node (SN: Secondary Node), including SpCell and optionally one or more Scells.

[0118] As previously mentioned, the frame structure for NR supports flexible configuration to accommodate various next-generation (e.g., 5G) communication requirements, such as enhanced mobile broadband (eMBB), massive machine type communication (mMTC), and ultra-reliable and low-latency communication (URLLC), while meeting high reliability, high data rate, and low latency requirements. The orthogonal frequency division multiplexing (OFDM) technology agreed upon in 3GPP can be used as the baseline for the NR waveform. Scalable OFDM parameter sets, such as adaptive subcarrier spacing, channel bandwidth, and cyclic prefix (CP), can also be used. In addition, two coding schemes are considered for NR: (1) low-density parity check (LDPC) code and (2) polar code. Coding scheme adaptation can be configured based on channel conditions and / or service applications.

[0119] In addition, it is also considered that the transmission time interval TX of a single NR frame should include at least downlink (DL) transmission data, protection period and uplink (UL) transmission data, wherein the respective parts of DL transmission data, protection period and UL transmission data should also be configurable, for example, based on the dynamic configuration of the NR network. In addition, sidelink resources can also be provided in the NR frame to support ProSe services or V2X services.

[0120] Furthermore, the terms "system" and "network" are used interchangeably. The term "and / or" in this document simply describes the relationship between associated objects, indicating three possible relationships. For example, "A and / or B" can mean: A exists alone, A and B exist simultaneously, or B exists alone. Furthermore, the character " / " generally indicates that the preceding associated object and the following associated object are in an "or" relationship.

[0121] As described above, the next generation (e.g., 5G NR) wireless networks are envisioned to support more capacity, data, and services. A UE configured with multi-connectivity can connect to a master node (MN) as an anchor point and one or more secondary nodes (SN) for data transfer. Each of these nodes may be formed by a cell group comprising one or more cells. For example, an MN may be formed by a primary cell group (MCG) and an SN may be formed by a secondary cell group (SCG). In other words, for a UE configured with dual connectivity (DC), an MCG is a set of one or more serving cells, including a PCell and zero or more secondary cells. In contrast, an SCG is a set of one or more serving cells, including a PSCell and zero or more secondary cells.

[0122] As mentioned above, the primary cell (PCell) can be an MCG cell operating on the primary frequency, where the UE performs the initial connection establishment process, or initiates the connection re-establishment process. In MR-DC mode, the PCell can belong to the MN. The primary SCG cell (PSCell) can be an SCG cell where the UE performs random access (for example, when reconfiguration is performed using a synchronization process). In MR-DC, the PSCell can belong to the SN. The special cell (SpCell) can be called the PCell of the MCG or the PSCell of the SCG, depending on whether the media access control (MAC) entity is associated with the MCG or the SCG. Otherwise, the term special cell can refer to the PCell. The special cell can support physical uplink control channel (PUCCH) transmission and contention-based random access, and can be activated at all times. In addition, for a UE in the RRC_CONNECTED state that is not configured with CA / DC, it can communicate with only one serving cell (SCell), which can be the primary cell. In contrast, for a UE in RRC_CONNECTED state configured with CA / DC, a set of serving cells including the special cell(s) and all secondary cells may communicate with the UE.

[0123] As described above, in NR, three different RRC states are supported as operating modes of the UE. These three states include the RRC_CONNECTED state, the RRC_IDLE state, and the RRC_INACTIVE state. The UE (or the RRC layer of the UE) can operate in one of these three RRC states. In addition to UL data transmission performed during the RA procedure, the UE can generally be allowed to perform UL data transmission only in the RRC_CONNECTED state.

[0124] Figure 11 is an RRC state transition diagram according to an exemplary embodiment of the present application, which illustrates various RRC states and RRC transition processes that a UE may experience within a next generation radio access network. The RRC state transition diagram 100 may include an RRC_CONNECTED state 110, an RRC_INACTIVE state 120, and an RRC_IDLE state 130. In some embodiments, the RRC connected state, the RRC inactive state, and the RRC idle state may be three independent RRC states. Figure 1 As shown, the UE can transition between three RRC states.

[0125] For example, the UE may transition from the RRC_CONNECTED state 110 to the RRC_INACTIVE state 120, or may transition from the RRC_INACTIVE state 120 to either the RRC_CONNECTED state 110 or the RRC_IDLE state 130. However, as shown in the RRC state transition diagram 100, in some embodiments, the UE may not transition directly from the RRC IDLE state 130 to the RRC INACTIVE state 120. That is, in some such embodiments, the UE may transition from the RRC IDLE state 130 to the RRC INACTIVE state 120 via the RRC CONNECTED state 110. In some aspects of the embodiments of the present invention, the UE may also transition from the RRC CONNECTED state 110 to the RRC INACTIVE state 120 using an RRC suspend (or RRC release with suspend) procedure. Conversely, the UE may transition from the RRC INACTIVE state 120 to the RRC CONNECTED state 110 using an RRC (Connection) Resume procedure. In addition, the UE may use an RRC release procedure to transition from the RRC connected state 110 or the RRC inactive state 120 to the RRC idle state 130 , and use an RRC setup procedure to transition from the RRC idle state 130 to the RRC connected state 110 .

[0126] In some embodiments, in the RRC_INACTIVE state, the UE may remain in Connection Management (CM)-CONNECTED (e.g., if the UE has a signaling connection with the AMF) and may move within the area configured by the NG-RAN (e.g., RNA) without notifying the NG-RAN. In the RRC_INACTIVE state, the last serving cell (e.g., associated with the gNB) may maintain the UE context and the NG connection associated with the UE serving the AMF and UPF.

[0127] In some embodiments, the RRC_INACTIVE state may support various functions and / or features, such as small data transfer (SDT), PLMN selection, system information broadcast, cell reselection mobility, paging initiated by NG-RAN (RAN paging), RAN-based notification area (RNA) managed by NG-RAN, DRX configured by NG-RAN for RAN paging, 5GC-NG-RAN connection established for the UE (e.g., both control plane / user plane (C / U), NG-RAN determining the RNA to which the UE belongs, etc. In some embodiments, for NR connected to a 5GC network, the UE's identity (e.g., I-RNTI) may be used to identify the UE context in the RRC_INACTIVE state. The I-RNTI may provide a reference to the UE context corresponding to the old NG-RAN node to the new NG-RAN node.

[0128] In some embodiments, the AS context of a UE in RRC_INACTIVE state may be stored upon connection termination (e.g., when the UE is in RRC_INACTIVE state) and may be restored / retrieved upon connection resumption (e.g., when the UE transitions from RRC_INACTIVE state to RRC_CONNECTED state). Termination of the RRC connection may be initiated by the network. When an RRC connection is terminated, the UE may store the UE inactive AS context (and any related configuration received from the network) and may transition to the RRC_INACTIVE state. If the UE is configured with an SCG, the UE may release the SCG configuration when initiating the RRC connection resumption procedure. The RRC message used to terminate the RRC connection may be integrity protected and encrypted. When the UE needs to transition from the RRC_INACTIVE state to the RRC_CONNECTED state, resumption of the terminated RRC connection may be initiated by upper layers, or by the RRC layer to perform an RNA update, or by, for example, a RAN paging from the NG-RAN. When the RRC connection is restored, the network may configure the UE according to the RRC connection restoration procedure and based on the stored UE inactive AS context (and any relevant RRC configuration received from the network). The RRC connection restoration procedure may reactivate AS security and reestablish (one or more) SRBs and (one or more) DRBs.

[0129] In some embodiments, in response to a request to resume the RRC connection, the network may perform any of the following procedures. In some embodiments, in response to such a request, the network may resume the suspended RRC connection and send the UE to the RRC_CONNECTED state, or may reject the request and send the UE to the RRC_INACTIVE state (e.g., using a wait timer). In some other embodiments, the network may directly re-suspend the RRC connection and send the UE to the RRC_INACTIVE state in response to the request, or may directly release the (RRC) connection and send the UE to RRC_IDLE mode. In yet other embodiments, in response to the request to resume the RRC connection, the network may instruct the UE to initiate NAS level recovery (e.g., by transmitting an RRC setup message to the UE).

[0130] In addition, in the RRC_INACTIVE state, the upper layer (or RRC layer) can configure specific DRX for the UE. The controlled mobility of the UE can be based on the network configuration in the RRC_INACTIVE state, and the UE can store the UE inactive AS context. In addition, when the UE is in the RRC_INACTIVE state, the RRC layer can configure a RAN-based notification area. In addition, when in the RRC_INACTIVE state, the UE can perform other functions, such as monitoring short messages (e.g., short messages transmitted via DCI with P-RNTI); monitoring the paging channel for CN paging (e.g., using 5G-S-TMSI) and RAN paging (e.g., using full I-RNTI); performing neighbor cell measurements and cell (re)selection; performing RAN-based notification area updates periodically and / or when moving outside the configured RAN-based notification area; and obtaining system information and transmitting SI (e.g., if configured).

[0131] Random access process

[0132] In some implementations, two types of random access (RA) procedures may be supported / configured for a UE. For example, a 4-step RA type with MSG1 and a 2-step RA type with MSGA. Both types of RA procedures support contention-based random access (CBRA) and contention-free random access (CFRA).

[0133] The UE selects the following random access types when initiating the random access procedure based on the network configuration, for example:

[0134] -When CFRA resources are not configured, the UE can use the RSRP threshold to select between 2-step RA type and 4-step RA type;

[0135] - When CFRA resources for 4-step RA type are configured, the UE may perform RA with 4-step RA type; and / or

[0136] - When CFRA resources for 2-step RA type are configured, the UE may perform RA with 2-step RA type.

[0137] Figure 2A FIG210 is a diagram illustrating a random access procedure with a 2-step RA type (e.g., for small data transmission) according to an exemplary embodiment of the present application. FIG210 includes a UE 202 and a base station 204 (e.g., a gNB), wherein the UE 202 can transmit an RRC recovery request and / or uplink (UL) data (e.g., small data) to the base station 204 via a random access procedure with a 2-step RA type.

[0138] like Figure 2A As shown, action 212 includes UE 202 transmitting a random access (RA) preamble and / or an RRC recovery request (e.g., MSG A) to base station 204. MSG A may include RACH resources and a PUSCH payload. The RA preamble may be transmitted via the RACH resources of MSG A. The RRC recovery request may be transmitted via the PUSCH payload of MSG A. Base station 204 may configure RACH resources that may be used for UE 202 to transmit the RA preamble. In some embodiments, RACH resources may be specifically configured for small data transmission purposes. UE 202 may select a RACH resource (for small data transmission purposes) from the configured RACH resources (e.g., specified by a combination of time resources, frequency resources, and sequence resources). UE 202 may then transmit the RA preamble using the selected RACH resource of MSG A (e.g., for small data transmission purposes). UE 202 may transmit the RRC recovery request via the PUSCH payload of MSG A. UL data (eg, small data) may also be multiplexed with the RRC recovery request to be transmitted via the PUSCH payload of MSG A.

[0139] like Figure 2A As shown, action 214 includes, for example, when the base station 204 detects the RA preamble and / or UL data, the base station 204 transmitting a random access response (RAR) (e.g., MSG B) to the UE 202. For UL data transmission (e.g., small data transmission), the base station 204 may provide an acknowledgement (ACK) / negative acknowledgement (NACK) message in MSG B to indicate to the UE 202 whether the base station 204 has successfully received the UL data in MSG A.

[0140] Figure 2BFIG220 is a diagram illustrating a random access procedure with a 4-step RA type (e.g., for small data transmission) according to an exemplary embodiment of the present application. FIG220 includes a UE 202 and a base station 204 (e.g., a gNB), wherein the UE 202 can transmit an RRC recovery request and / or UL data (e.g., small data) to the base station 204 via a random access procedure with a 4-step RA type.

[0141] like Figure 2B As shown, action 222 includes UE 202 transmitting an RA preamble (e.g., MSG 1) to base station 204. Base station 204 may configure RACH resources available for UE 202 to transmit the RA preamble. In some embodiments, the RACH resources may be specifically configured for small data transmission purposes. In some embodiments, UE 202 may select a RACH resource (for small data transmission purposes) from the configured RACH resources (e.g., specified by a combination of time resources, frequency resources, and sequence resources). UE 202 may then use the selected RACH resource (e.g., for small data transmission purposes) to transmit the RA preamble.

[0142] Action 224 includes, for example, when the base station 204 detects the RA preamble, the base station 204 transmitting the RAR (e.g., MSG 2) to the UE 202. Since the base station 204 may not be able to identify the UE 202 that transmitted the RA preamble, the RAR may be transmitted over the entire cell covered by the base station 204. For example, the physical downlink shared channel (PDSCH) resource in which the RAR is mapped may be indicated to the UE 202 by the base station 204 via the physical downlink control channel (PDCCH). In addition, the RAR may contain information about resources to be used by the UE 202 in the uplink or information about the uplink transmission timing of the UE 202.

[0143] Action 226 includes, in action 224, UE 202 transmitting an RRC recovery request (e.g., MSG 3) using uplink resources (e.g., PUSCH resources) provided by base station 204 via the RAR. In some embodiments of the present invention, UE 202 may transmit an RRC recovery request message to base station 204, wherein the RRC recovery request message may or may not request a transition to the RRC_CONNECTED state. In some embodiments, UL data (e.g., small data) may also be multiplexed with the RRC recovery request message to be transmitted via MSG 3.

[0144] Action 228 includes base station 204 transmitting a PDCCH transmission for contention resolution (e.g., MSG 4) to UE 202. In some embodiments of the present invention, base station 204 may provide an acknowledgement (ACK) / negative acknowledgement (NACK) message in MSG 4 to indicate to UE 202 whether base station 204 has successfully received the UL data in MSG 3.

[0145] In some embodiments, an MSGA with a RA procedure of a 2-step RA type may include a preamble on the PRACH and a payload on the PUSCH. In some such embodiments, after the MSGA transmission, the UE may monitor for a response from the network within a configured window. For CFRA, upon receiving the network response, the UE may end the random access procedure. For CBRA, if contention resolution is successful, for example, upon receiving the network response, the UE may end the random access procedure. If a fallback indication is received in the MSGB, the UE may perform an MSG3 transmission and monitor for contention resolution. If contention resolution is unsuccessful after the MSG3 (re)transmission, the UE may return to the MSGA transmission. In some embodiments, if the random access procedure with a 2-step RA type is not completed after multiple MSGA transmissions, the UE may be configured to switch to a CBRA with a 4-step RA type.

[0146] For random access in a cell configured with SUL, the network can explicitly signal which carrier can be used (e.g., UL or SUL carrier), otherwise, if the measured DL quality is below a broadcast threshold, the UE can select the SUL carrier. The UE can perform carrier selection before selecting an RA procedure with a 2-step or 4-step RA type. The RSRP threshold for selecting between 2-step and 4-step RA types can be configured separately for UL and SUL. Once started, all uplink transmissions of the random access procedure can remain on the selected carrier.

[0147] Configured authorization

[0148] In some embodiments, in the uplink, a base station (e.g., a gNB) can dynamically allocate resources to a UE, for example, via a C-RNTI / CS-RNTI on the PDCCH. When downlink reception is enabled, the UE can monitor the PDCCH to find possible configured grants for uplink transmission (e.g., when configured, the UE can manage activity via DRX). When Carrier Access Control (CA) is configured, the same C-RNTI / CS-RNTI can apply to all serving cells. In addition, the base station can allocate uplink resources for initial HARQ transmissions to the UE using the configured grants.

[0149] In some embodiments, two types of configured uplink grants can be configured. For Type 1 Configured Grant (CG), RRC signaling can directly provide the configured uplink grant (e.g., including the period). For Type 2 CG, RRC signaling can define the period of the configured uplink grant, and the PDCCH addressed to the CS-RNTI can signal the configured uplink grant and activate or deactivate it. That is, the PDCCH addressed to the CS-RNTI can indicate that the uplink grant can be implicitly reused according to the period defined by RRC signaling until it is deactivated.

[0150] In some embodiments, Type 1 and Type 2 CGs are configured per serving cell and BWP via RRC signaling. In some such embodiments, multiple configurations can be active simultaneously, for example, on different serving cells. For Type 2 CGs, activation and deactivation can depend on the serving cell. For the same serving cell, the UE / MAC entity can be configured with either Type 1 or Type 2.

[0151] In some embodiments, when configuring a configured grant type 1, RRC may configure different parameters. For example, RRC may configure the cs-RNTI parameter, which is used for retransmissions; the periodicity parameter, which indicates the period of the configured grant type 1; the timeDomainOffset parameter, which indicates the offset of resources in the time domain relative to SFN=0; the timeDomainAllocation parameter, which is used to allocate the configured uplink grant in the time domain, which may contain the startSymbolAndLength (e.g., SLIV in technical specification 38.214); and the nrofHARQ-Processes parameter, which indicates the number of HARQ processes for the configured grant.

[0152] When a configured grant type 1 for a serving cell is configured (e.g., by upper layers), the UE / MAC entity may store the uplink grant provided by the upper layers as the configured uplink grant for the indicated serving cell. The UE / MAC entity may also initialize or reinitialize the configured uplink grant to start in symbol 1 based on the timeDomainOffset and S (derived from SLIV specified in Technical Specification (TS) 38.214) parameters and to repeat periodically.

[0153] As described above, in NR, small UL data transmission (SDT) in the RRC_INACTIVE state may be possible. The solution for small data transmission in the RRC_INACTIVE state may be service-independent, resulting in different service requirements. In some embodiments, small data transmission can be achieved by using a RACH-based mechanism (e.g., through an RA procedure with a 2-step and / or 4-step RA type) and / or using pre-configured PUSCH resources (e.g., a configured grant type 1).

[0154] The UE AS context used for uplink data transmission in the RRC_INACTIVE state (e.g., the UE inactive AS context) may be similar to the context used in a state transition from the RRC_INACTIVE state to the RRC_CONNECTED state. The UE AS context may be located and identified in the network via an "AS context ID," which may be allocated by the network and stored in the UE (e.g., and in the network) when the UE transitions to the RRC_INACTIVE state and may be used to locate the AS context when the UE attempts to transmit small data and / or performs a transition to the RRC_CONNECTED state. The UE AS context may be stored in the "anchor" / source base station and may be retrieved by the new serving base station when needed, for example, upon triggering a small data transmission and / or transitioning from the RRC_INACTIVE state to the RRC_CONNECTED state. The UE ID may be able to uniquely identify the UE context in the RAN.

[0155] Small data transmission may use the AS context ID transmitted in the "first" message for contention resolution (e.g., at least when using RACH). After receiving the "first" message with small data, the network may be able to inform the UE that it can move to the RRC_CONNECTED state, for example, via a DL RRC message (e.g., an RRCConnectionResume message). If necessary, the "first" message with small data may provide information that enables the network to apply overload control and prioritization. The UE may provide the network with all necessary information in the "first" message with the initial uplink data transmission to enable the network to move the UE to the RRC_CONNECTED state, or to enable the network to keep the UE in the RRC_INACTIVE state. For example, this information may include a BSR.

[0156] In some embodiments, small data transmission can at least support the RLC ARQ mechanism. When the UE transmits small data in the RRC_INACTIVE state, the network may have the ability to perform a context update. The context update may rely on RRC signaling and may be completed in a "second" message (e.g., an RRCConnectionResume message or a control response message triggered by small data transmission). The UE context in the RRC_INACTIVE state may include configurations such as radio bearers, logical channels, security, etc. The UE may maintain the same PDCP entity as in the RRC_CONNECTED state, and maintain the PDCP COUNT and the SN of the PDCP entity.

[0157] One or more specific RBs (e.g., DRBs and / or SRBs) may remain in the RRC_INACTIVE state, and small data transmission may occur on the DRBs and / or SRBs associated with the relevant service. For small data transmission in the RRC_INACTIVE state, the UE may perform small data transmission on configured RBs (e.g., DRBs and / or SRBs configured for small data transmission). If a bearer with configured QoS is allowed to be used for UL small data transmission, QoS may still need to be met.

[0158] In some embodiments, the RRC connection resume request may contain at least the information required for the network to perform contention resolution, identify the UE AS context, and verify the correct UE. Upon receiving a response from the network (e.g., an RRCConnectionResume message), the UE may be able to identify the correct network, perform contention resolution, and receive DL data and remain in the RRC_INACTIVE state or resume its previously suspended connection (e.g., move to the RRC_CONNECTED state). DL transmission / response and subsequent UL transmission may be supported without the UE having to move to the RRC_CONNECTED state.

[0159] When transmitting MSG3, HARQ ACK / NACK transmission may be supported (e.g., once the UE has transmitted the first UL data packet, the UE is expected to continuously monitor the DL PDCCH, and DL RLC ACK / NACK messages may be scheduled normally while the UE is still listening to the DL channel). The UE may provide information to the network to enable the network to decide whether to leave the UE in the RRC_INACTIVE state or move the UE to the RRC_CONNECTED state.

[0160] In some embodiments, MSG 1 may be used for RA preamble transmission in a random access procedure with a 4-step RA type; MSG 3 may be used for the first modulation transmission in a random access procedure; MSG A may be used for RA preamble and PUSCH payload transmission in a random access procedure with a 2-step RA type; MSG B may be used to respond to MSG A in a random access procedure with a 2-step RA type. In some aspects of the embodiments of the present invention, MSG B may include one or more responses for contention resolution, fallback indication, and / or backoff indication.

[0161] Supports UL / small data transmission configuration in RRC_INACTIVE state

[0162] As mentioned above, UL data transmission (e.g., SDT) can be supported in the RRC_INACTIVE state. Based on the RRC state machine and the state transition in NR, as mentioned above Figure 1 As described above, the RRC state of the UE can be controlled by the NW. Specifically, the NW can switch the RRC state of the UE from the RRC_CONNECTED state to the RRC_INACTIVE state by transmitting an RRC release message (e.g., with an abort configuration) to the UE. In some aspects of the preset implementation methods, if the UE is in the RRC_IDLE state, it may be necessary to first switch the RRC state of the UE to the RRC_CONNECTED state before switching its state to RRC_INACTIVE. In other words, in some implementations, the RRC state of the UE cannot be switched directly from the RRC_IDLE state to the RRC_INACTIVE state.

[0163] In some embodiments, the UL data transmission configuration may be configured via an RRC release with an abort configuration or via a specific configuration for UL data transmission included in an RRC release command (and / or in an abort configuration in an RRC release message). Alternatively, the UL data transmission (e.g., SDT) configuration may be pre-configured via a specific RRC configuration. For example, the UE may receive the SDT configuration via an RRC reconfiguration message (e.g., from a serving cell when the UE is in the RRC_CONNECTED state) via dedicated RRC signaling.

[0164] The UL data transmission (e.g., SDT) configuration may include a 4-step RACH configuration, a 2-step RACH configuration, a configuration grant configuration, a radio bearer configuration, a BWP indicator, a UE (context) ID, a time alignment (TA) configuration, a paging configuration, a RAN notification area configuration, and the like. For example, when the UE is configured to support UL data transmission in the RRC_INACTIVE state, these configurations, described in more detail below, may be applied by the UE. More specifically, when the UE receives the UL data transmission configuration, the UE may enter the RRC_INACTIVE state. In some embodiments, the UL data transmission (e.g., SDT) configuration may be applied when the UE is in the RRC_INACTIVE state.

[0165] RACH Configuration: In some embodiments, a specific preamble and / or PRACH resource may be configured for SDT. The specific preamble and / or PRACH resource may be associated with a specific grant size for MSG3. The UE may select a preamble and / or PRACH resource to initiate an RA procedure for SDT (e.g., UL data transmission in RRC_INACTIVE state) based on certain criteria (e.g., based on RB, TA, data volume, buffer status, channel quality, etc.). In some embodiments, the RACH configuration may be included in the RRC release message.

[0166] 2-step RACH configuration: In some embodiments, a specific preamble, PRACH resources, and / or MSG A PUSCH resources may be configured for SDT. The specific preamble and / or PRACH resources may be associated with a specific grant size for MSG A PUSCH. The UE may select the preamble, PRACH resources, and / or associated MSG A PUSCH for SDT based on certain criteria (e.g., based on RB, TA, data volume, buffer status, channel quality, etc.). In some embodiments, the 2-step RACH configuration may be included in the RRC release message.

[0167] Configured grant configuration: In some embodiments, the configured grant configuration included in the UL data transmission (e.g., SDT) configuration may include one or more parameters listed in the IE ConfiguredGrantConfig, for example, as described in 3GPP TS 38.321 (e.g., the period of the configured grant, the size of the UL resources, the duration of the UL resources, etc.) and / or other parameters (e.g., the number and / or threshold available for CG release, TA timer for TA validity, RSRP threshold, time offset, UE-specific RNTI, configured grant ID and / or timer / window for responding to UL transmissions with configured grants, number of HARQ processes, etc.). In some embodiments, the CG configuration may be included in the RRC release message.

[0168] As described above, the configured grant configuration may be a type 1 and / or type 2 configured grant. The configured grant configuration may include contention-based resources and / or contention-free resources. Such a configured grant configuration may only be used in the RRC_INACTIVE state and / or may be used in the RRC_CONNECTED state and the RRC_INACTIVE state. The configured grant configuration may include dedicated UL resources for the UE. The UE may be configured with multiple configured grant configurations, for example, for transmissions in the RRC_INACTIVE state. More specifically, the number of transmissions via the configured grant may be configured in the configured grant configuration. For example, if the number of transmissions is 2, the UE may use only two configured grants for transmission.

[0169] In some embodiments, the UE may maintain a counter and decrement the counter by one after each transmission via the configured grant / resource. In some such embodiments, if the counter reaches zero, the UE may clear / release the configured grant configuration or the configured granted resource. More specifically, in some embodiments, a timer may be configured in the configured grant configuration. Such a timer may be used to reflect whether the configured grant / resource is valid. In some embodiments, the configured grant configuration or the configured granted resource may only be valid while the timer is running (e.g., not expired or not reaching zero).

[0170] Radio Bearer Configuration: In some embodiments, one or more of the specific SRBs and / or DRBs may be configured for SDT. In some embodiments, the specific SRBs and / or DRBs may be resumed when the UE initiates the SDT procedure. In some embodiments, when the RRC state of the UE switches to the RRC_INACTIVE state (e.g., when the UE receives an RRC release with a suspension configuration and / or SDT configuration), the specific SRBs and / or DRBs may not be suspended. In some embodiments, the radio bearer configuration may be included in the RRC release message.

[0171] BWP indicator: In some embodiments, a specific BWP (ID) can be configured for use by the UE in the RRC_INACTIVE state (e.g., for SDT). For example, if the UE receives a BWP indicator and / or if the UE initiates an SDT procedure, the UE can switch the active BWP to the indicated / configured BWP upon entering the RRC_INACTIVE state (e.g., via the BWP indicator). In the RRC_INACTIVE state, the UE can receive system information broadcast on the indicated BWP. The indicated / configured BWP can be configured with a CG configuration. The UE can then perform UL data transmission on the indicated / configured BWP (e.g., via a configured grant). The indicated / configured BWP can be an initial BWP, a default BWP, and / or a specific BWP. In some embodiments, the BWP indicator can be included in the RRC release message.

[0172] UE (Context) ID: In some embodiments, the UE (Context) ID can be referred to as a specific RNTI (e.g., I-RNTI, full I-RNTI, short I-RNTI, C-RNTI, CS-RNTI, a specific RNTI for SDT, etc.), a UE AS context ID, a UE inactive AS context, etc. In some embodiments, the UE ID can be transmitted along with UL data transmission. For example, the UE ID can be transmitted via MSG1, MSG 3, MSGA, and / or UL resources derived from a configured grant. In some embodiments, the UE ID can be used by the UE when receiving a request for UL data transmission (e.g., via a configured grant). In some embodiments, the UE (Context) ID can be included in the RRC release message.

[0173] Time Alignment (TA) Configuration: In some embodiments, a specific TA timer may be configured for use by the UE in the RRC_INACTIVE state. In some embodiments, when the UE receives the TA configuration, the UE may (re)start the specific TA timer. In some embodiments, when the UE receives a specific timing advance command (e.g., via a paging message, a short message and / or other DL signaling, such as via PDCCH and / or a specific DCI format), the UE may apply the timing advance command and / or (re)start the specific TA timer. The timing advance command (e.g., a timing advance command MAC CE) may be used to update the TA value for UL synchronization. When the specific TA timer is running (e.g., not expired or has not reached zero), the UE may determine that the TA is valid. If the specific TA timer expires (or is not running), the UE may determine that the TA is invalid. In some embodiments, if the TA is determined to be valid, the UE may only use the configured grant for transmissions in the RRC_INACTIVE state. Otherwise, if it is determined that the TA is invalid, the UE may initiate an RRC connection recovery procedure and / or a random access procedure, while requiring the UE to transmit UL data (e.g., in the RRC_INACTIVE state).In some embodiments, the time alignment (TA) configuration may be included in the RRC release message.

[0174] Paging configuration: In some embodiments, when the UE is in RRC_INACTIVE state, a paging cycle may be configured for UL data transmission. In some embodiments, the paging configuration may be included in the RRC release message.

[0175] RAN Notification Area Configuration: In some embodiments, the RAN Notification Area Configuration may include a cell ID list, a RAN Area Configuration list, a RAN Area Code (RANAC) list, a RAN Area ID list, and / or a Tracking Area Code list. A specific timer for the RAN Notification Area (e.g., similar to t380 introduced by 3GPP) may be configured for the UE. In some embodiments, the RAN configuration may be included in the RRC Release message.

[0176] As described above, the UL data transmission (e.g., SDT) configuration and corresponding parameters may be configured via an RRC release message (e.g., with an abort configuration). In some embodiments, when a UE in an RRC_CONNECTED state receives an UL data transmission configuration / SDT configuration (e.g., RACH configuration, 2-step RACH configuration, configured authorization configuration, radio bearer configuration, BWP indicator, UE (context) ID, time alignment (TA) configuration, paging configuration, and / or RAN notification area configuration), the UE may switch its RRC state to an RRC_INACTIVE state and may apply the UL data transmission (e.g., SDT) configuration. The UE may perform UL and / or DL ​​data transmission after the UL data transmission (e.g., SDT) configuration in the RRC_INACTIVE state, for example, without performing a state transition to the RRC_CONNECTED state. In addition, the UE may or may not reset the MAC entity (or may partially reset the MAC entity). The UE may or may not release the default MAC cell group configuration.

[0177] Select UL grant type for UL / small data transmission in RRC_INACTIVE state

[0178] In some current embodiments, the UE / MAC entity may determine how to use a received or configured UL grant. If the UE has received an UL grant or there is a configured UL grant (e.g., an activated / initialized CG configuration), the UE / MAC entity may determine (e.g., based on a new data indicator (NDI)) the UL grant to use for a new transmission or retransmission. Accordingly, the UE / MAC entity may pass the UL grant and associated HARQ information (e.g., NDI, transport block size (TBS), redundancy version (RV), and / or HARQ process ID) to the UE's HARQ entity.

[0179] For each UL grant, the UE's HARQ entity may identify the HARQ process associated with the corresponding UL grant. For each identified HARQ process, the UE's HARQ entity may determine the type of the corresponding UL grant (e.g., whether the UL grant is for a new transmission or for a retransmission, whether the UL grant is received in the RAR, whether the UL grant is a configured grant, etc.). The UE's HARQ entity may then obtain a MAC PDU (e.g., for transmission) from the UE's multiplexing and assembly entity. If a MAC PDU for transmission has been obtained, the UE's HARQ entity may pass the MAC PDU and the UL grant and HARQ information (e.g., MAC PDU) for the TB to the identified HARQ process. If the UE's HARQ entity requests a new transmission for the TB, the UE's HARQ process may store the MAC PDU in an associated HARQ buffer, store the UL grant received from the HARQ entity, and / or generate a transmission. If the UE's HARQ entity requests a retransmission for the TB, the UE's HARQ process may store the uplink grant received from the HARQ entity, and / or generate a transmission. To generate a transmission for a TB, the UE's HARQ process may instruct the physical layer to generate a transmission according to the stored UL grant.

[0180] In some embodiments, the UE may generate data for transmission (e.g., MAC PDU / TB) when the UE receives an UL grant or before the transmission time of (each) configured grant (e.g., the start symbol of the PUSCH resource). To generate the data for transmission, the UE / MAC entity may perform a multiplexing and assembly process and / or an LCP process to obtain data from the logical channels and / or the generated MAC CE. If at least some UL data for the logical channel becomes available, the UE / MAC entity may trigger a BSR (e.g., when certain criteria (such as those specified in 3GPP TS 38.321) are also met), where the BSR may be used to provide information about the amount of UL data and / or buffer status to the network.

[0181] For example, when there is UL data received from upper layers (e.g., RRC, SDAP, PDCP and / or RLC) by LCH (e.g., CCCH, DCCH and / or DTCH), the MAC entity of the UE can determine that there is available UL data. If a BSR has been triggered, the UE can check whether there are any UL resources (e.g., PUSCH resources) available for (new) transmission. If there are no available UL resources, the UE can trigger an SR, where the SR can be used to request UL-SCH resources for the new transmission. As long as at least one SR is pending, the UE can check whether there are any valid PUCCH resources configured for the pending SR. If there are no valid PUCCH resources, the UE can initiate a RA procedure (e.g., on a SpCell and / or on a cell where the UE resides in RRC_IDLE / RRC_INACTIVE state).

[0182] It should be noted that UL resources may be considered available when the UE / MAC entity has an active configuration for either type of configured uplink grant (e.g., Type 1 or Type 2), or when the UE / MAC entity has received a dynamic uplink grant, or both conditions are met.

[0183] In some embodiments of the present invention, when the UE is in the RRC_INACTIVE state, no PUCCH resources may be configured / valid. This is because when the UE switches its RRC state from RRC_CONNECTED to RRC_INACTIVE, the UE may reset the MAC entity and consider the TA timer to have expired. Upon determining that the TA timer has expired, the UE may release, for example, the PUCCH resources associated with all cells.

[0184] According to the latest 3GPP NR versions (e.g., R-15 and / or R-16), when the UE is in the RRC_INACTIVE state, if the UE needs to transmit UL data, the UE may need to restore its connection (e.g., move to the RRC_CONNECTED state). To this end, the UE may initiate an RRC connection recovery procedure and / or initiate the transmission of an RRCResumeRequest message. The RRCResumeRequest message may be transmitted via a logical channel (e.g., CCCH). From the perspective of the UE / MAC entity, if there is UL data received by the LCH (and no other logical channels contain any available UL data), the UE may trigger a BSR. Since there are no available UL resources in the RRC_INACTIVE state, the UE may trigger an SR. Therefore, when there are no valid PUCCH resources in the RRC_INACTIVE state, the UE may initiate a RA procedure. Therefore, the UE may use the UL resources of the RA procedure to transmit the RRCResumeRequest message. In some embodiments, the UL resources may be a MSG APUSCH. In some embodiments, the UL resources may be received in the RAR.

[0185] In some embodiments of the present invention, at least three types of UL grants may be supported for UL data transmission in the RRC_INACTIVE state (e.g., SDT). UL grants may be provided during a RA procedure with a 4-step RA type, a RA procedure with a 2-step RA type, and / or a configured PUSCH resource (e.g., CG type 1). For a RA procedure with a 4-step RA type, the UE may transmit UL data via a UL grant received from the RAR (e.g., UL data may be transmitted via MSG 3). For a RA procedure with a 2-step RA type, the UE may transmit UL data via a UL grant pre-configured for MSG A (e.g., UL data may be transmitted via the PUSCH resources of MSG A). For configured PUSCH resources, the UE may transmit UL data via an activated / initialized configured grant (UL data may be transmitted via the PUSCH resources of the CG). Therefore, if more than one type of UL grant is configured for the UE, the UE may have to determine which type of UL grant must be used to transmit UL data (e.g., small data).

[0186] The types of UL grants can be grouped into RACH-based mechanisms (e.g., 4-step RA type and / or 2-step RA type) and CG-based mechanisms (e.g., configured grant type 1). As discussed herein, several different criteria can be determined by the UE to select a RACH-based or CG-based mechanism for UL data transmission (e.g., SDT) in the RRC_INACTIVE state. Furthermore, in the event that the UE selects a RACH-based mechanism, the UE can determine different criteria to select a 4-step RA type or a 2-step RA type for UL data transmission (e.g., SDT) while in the RRC_INACTIVE state.

[0187] For RACH-based mechanisms, the UE may be configured with only 2-step RA (e.g., via rach-ConfigCommonTwoStepRA), only 4-step RA (e.g., via rach-ConfigCommon), or both 2-step and 4-step RA.

[0188] In a two-step RA, the UE may be configured with one or more PUSCH resources for MSG A. In some embodiments, the UE may be configured with one or more preamble groups. More specifically, the number of PUSCH resources for MSG A may be consistent with the number of preamble groups configured in the RACH-ConfigCommonTwoStepRA parameter. More specifically, different preamble groups and / or different PUSCH resources for MSG A may be associated with different characteristics (e.g., payload size, MCS, DMRS, number of PUSCH opportunities, etc.).

[0189] In 4-step RA, a UE may be configured with one or more preamble groups. More specifically, different preamble groups may be associated with different characteristics (e.g., the payload size of MSG3).

[0190] In a CG-based mechanism, a UE may be configured with zero, one or more CG resources, e.g., for SDT, and / or for UL data transmission in the RRC_INACTIVE state. In some embodiments, different CG configurations / resources may have different characteristics (e.g., payload size, period, MCS, number of repetitions, number of HARQ processes, etc.). In some embodiments, a CG may be a dedicated PUSCH resource for a specific UE and / or a common PUSCH resource shared by a group of UEs. In some embodiments, when a UE is configured with multiple CG configurations / resources (e.g., for SDT, and / or for UL data transmission in the RRC_INACTIVE state), there may be zero, one, or several CG configurations / resources initialized / activated in the RRC_INACTIVE state. In some embodiments, the UE may determine that only the initialized / activated CG configurations / resources are valid or available for UL data transmission in the RRC_INACTIVE state.

[0191] Select RACH-based or CG-based mechanism for UL / small data transmission in RRC_INACTIVE state

[0192] As described above, in some embodiments of the present invention, the UE may be configured with one or more RACH resources (e.g., for 4-step RA type and / or 2-step RA type) and one or more CG resources (e.g., CG type 1) (e.g., for SDT). When at least some UL data associated with at least one radio bearer / logical channel becomes available and / or a BSR is triggered (e.g., when the UE is in RRC_INACTIVE state), one or more of the following alternative criteria may be applied: the UE determines whether to use the CG configuration / resources for UL data transmission (e.g., SDT) to trigger the SR and / or initiate a RA procedure (and / or initiate an RRC connection recovery procedure). In some embodiments, the UE may apply one or any combination of the following alternative criteria to determine whether there are any valid / available UL resources and / or CG resources for (new) transmission. In some embodiments, when the UE is in RRC_INACTIVE state, the UE may apply one or any combination of the following alternative criteria to determine whether to transmit UL data (e.g., small data) via the UL resources configured by the CG configuration.

[0193] Criteria 1-1: Based on whether any CG configuration / resource has been initialized / activated:

[0194] In some embodiments of the present invention, whether the CG configuration / resources can be used by the UE for UL data transmission, or whether the CG configuration / resources are determined to be valid / available, can be determined based on whether the CG configuration has been initialized / activated. That is, in some embodiments, if the CG configuration / resources are suspended / deactivated / released, the CG configuration / resources may not be used for UL data transmission. Similarly, if the UE determines that the CG configuration / resources are invalid / unavailable, the CG configuration / resources may not be used for UL data transmission. In some embodiments, the CG configuration may be initialized / activated when the CG is configured for the UE. For example, when the UE receives the CG configuration, the CG configuration may be initialized / activated. In some embodiments, the NW may send an indication to the UE to initialize / activate the CG configuration / resources and / or suspend / deactivate / release the CG configuration / resources. In some embodiments, the UE may receive (e.g., from the NW) a CG configuration and / or an index associated with the CG configuration to be initialized / activated or suspended / deactivated / released in the RRCRelease message (e.g., with a suspension configuration). In some embodiments, when the UE receives an RRCRelease message including a specific CG configuration, for example, for SDT, the UE may transition from the RRC_CONNECTED state to the RRC_INACTIVE state. The UE may then initiate / activate the specific CG configuration, and / or suspend / deactivate / release other CG configurations (e.g., not for SDT). The UE may determine whether to use the CG configuration / resources for UL data transmission (e.g., SDT) to trigger an SR, initiate an RA procedure (e.g., for SDT), and / or initiate an RRC connection recovery procedure, for example, based on whether any CG configuration has been initialized and / or activated.

[0195] In some embodiments, when the UE is in the RRC_INACTIVE state, the UE may be configured with a first CG configuration. In some such embodiments, when at least some UL data associated with the radio bearer / logical channel becomes available and / or a BSR is triggered (e.g., when the UE is in the RRC_INACTIVE state), the UE may determine, for example, based on whether the first CG configuration has been initialized / activated, whether to use the CG configuration / resources for UL data transmission (e.g., SDT) to trigger an SR, initiate a RA procedure (e.g., for SDT), and / or initiate an RRC connection recovery procedure. If the first CG configuration has been configured and / or initialized / activated, the UE may use the CG configuration / resources for UL data transmission (e.g., SDT). As a result, the UE may not trigger an SR, may not initiate a RA procedure, and / or may not initiate an RRC connection recovery procedure. More specifically, the UE may determine whether there are valid / available UL resources for UL data transmission (e.g., SDT) in the RRC_INACTIVE state based on whether the first CG configuration has been initialized / activated. In other words, if the first CG configuration has not been configured and / or initialized / activated, the UE may trigger an SR, initiate an RA procedure and / or initiate an RRC connection recovery procedure.

[0196] In some embodiments, when the UE is in the RRC_INACTIVE state, the UE may be configured with multiple CG configurations, such as a first CG configuration and a second CG configuration. In some embodiments, when at least some UL data associated with a radio bearer / logical channel becomes available and / or a BSR is triggered (e.g., when the UE is in the RRC_INACTIVE state), the UE may determine, for example, based on whether at least one of the first and second CG configurations has been initialized / activated, whether to use the CG configuration / resources for UL data transmission (e.g., SDT) to trigger an SR, initiate an RA procedure (e.g., for SDT), and / or initiate an RRC connection recovery procedure. If at least one of the first and second CG configurations has been configured and / or initialized / activated, the UE may use the CG configuration / resources for UL data transmission (e.g., SDT). As a result, the UE may not trigger an SR, may not initiate an RA procedure, and / or may not initiate an RRC connection recovery procedure. More specifically, the UE may determine whether there are valid / available UL resources for UL data transmission (e.g., SDT) in the RRC_INACTIVE state based on whether the first CG configuration has been initialized / activated. In other words, if the first and second CG configurations have not yet been configured and / or initialized / activated, the UE may trigger an SR, initiate an RA procedure and / or initiate an RRC connection recovery procedure.

[0197] In some embodiments, when the UE is in the RRC_INACTIVE state, a specific (UL) BWP of the UE may be configured with one or more CG configurations, for example, for small data transmission. If at least some UL data associated with a radio bearer / logical channel becomes available and / or a BSR is triggered while the UE is in the RRC_INACTIVE state, the UE may determine whether to trigger a SR, initiate a RA procedure (e.g., for SDT), and / or initiate an RRC connection recovery procedure using the CG configuration / resources for UL data transmission (e.g., SDT), based on whether at least one of the configured CG configurations for the specific (UL) BWP has been initialized / activated. When at least one of the configured CG configurations for the specific (UL) BWP has been initialized / activated, the UE may not trigger a SR and / or may not initiate a RA procedure and / or may not initiate an RRC connection recovery procedure. Otherwise, the UE may perform small data transmission via the RA procedure. In some embodiments, the specific (UL) BWP may or may not be the (UL) BWP indicated / configured by the base station as a specific (UL) BWP for small data transmission. In some implementations, when the UE is in the RRC_INACTIVE state, a specific (UL) BWP may be determined as an active (UL) BWP.

[0198] In some embodiments, when the UE is in the RRC_INACTIVE state, a specific (UL) BWP of the UE may be configured with one or more CG configurations for small data transmission. When the UE is in the RRC_INACTIVE state, when at least some UL data associated with a radio bearer / logical channel becomes available and / or a BSR is triggered, the UE may determine whether to use the CG configuration / resources for UL data transmission (e.g., SDT) to trigger an SR, initiate an RA procedure (e.g., for SDT), and / or initiate an RRC connection recovery procedure based on whether at least one of the configured CG configurations of the UL BWP is configured with an rrc-ConfiguredUplinkGrant (e.g., as defined in 3GPP TS 38.331) and / or has been initialized / activated. If at least one of the configured CG configurations of the UL BWP is configured with an rrc-ConfiguredUplinkGrant and / or has been initialized / activated, the UE may use the CG configuration / resources for UL data transmission (e.g., SDT), and the UE may not trigger an SR, may not initiate an RA procedure (and / or may not initiate an RRC connection recovery procedure). Otherwise, the UE may perform small data transmission via the RA procedure. For example, the UE may trigger an SR, initiate an RA procedure, and / or initiate an RRC connection recovery procedure. In some embodiments, the specific (UL) BWP may or may not be the (UL) BWP indicated / configured by the base station as the (UL) BWP for small data transmission. In some embodiments, when the UE is in the RRC_INACTIVE state, the specific UL BWP may be determined as the active (UL) BWP.

[0199] In some embodiments, when the UE is in the RRC_INACTIVE state, the UE's specific serving cell may be configured with one or more CG configurations for small data transmission. If at least some UL data associated with the radio bearer / logical channel becomes available and / or a BSR is triggered when the UE is in the RRC_INACTIVE state, the UE may determine whether to use the CG configuration / resources for UL data transmission (e.g., SDT) to trigger SR, initiate an RA procedure (e.g., for SDT), and / or initiate an RRC connection recovery procedure, for example, based on whether the CG configuration of the specific serving cell has been initialized / activated. If at least one of the CG configurations of the serving cell has been initialized / activated, the UE may use the CG configuration / resources for UL data transmission (e.g., SDT), and the UE may not trigger SR, may not initiate an RA procedure, and / or may not initiate an RRC connection recovery procedure. Otherwise, the UE may perform small data transmission via the RA procedure. For example, the UE may trigger SR, initiate an RA procedure, and / or initiate an RRC connection recovery procedure. In some embodiments, the UE's specific (UL) BWP may or may not be a serving cell that is indicated / configured by the base station as a serving cell for small data transmission. In some implementations, when the UE is in the RRC_INACTIVE state, a specific serving cell may be determined as an active serving cell.

[0200] In some embodiments, when the UE is in the RRC_INACTIVE state, a specific serving cell of the UE may be configured with one or more CG configurations for small data transmission. If at least some UL data associated with a radio bearer / logical channel becomes available and / or a BSR is triggered while the UE is in the RRC_INACTIVE state, the UE may determine whether to use the CG configuration / resources for UL data transmission (e.g., SDT) to trigger SR, initiate an RA procedure (e.g., for SDT), and / or initiate an RRC connection recovery procedure, for example, based on whether at least one of the configured CG configurations of the serving cell is configured with an rrc-ConfiguredUplinkGrant (e.g., as defined in 3GPP TS 38.331) and / or has been initialized / activated. If at least one of the configured CG configurations of the serving cell has been configured with an rrc-ConfiguredUplinkGrant and has been initialized and activated, the UE may use the CG configuration / resources for UL data transmission (e.g., SDT). As a result, the UE may not trigger an SR, may not initiate an RA procedure, and / or may not initiate an RRC connection recovery procedure. Otherwise, the UE may perform small data transmission via the RA procedure. For example, the UE may trigger an SR, initiate an RA procedure, and / or initiate an RRC connection recovery procedure. In some embodiments, the UE's specific (UL) BWP may or may not be a serving cell, which is indicated / configured by the base station as a serving cell for small data transmission. In some embodiments, when the UE is in the RRC_INACTIVE state, the specific serving cell may be determined as an active serving cell (e.g., SpCell).

[0201] Criteria 1-2: Based on one or more characteristics of CG configuration / resources (e.g., payload size, number of repetitions, periodicity, SLIV, number of HARQ processes, HARQ information, timers, etc.).

[0202] In some embodiments, the UE may be configured with one or more CG configurations. The CG configuration may be initialized / activated and may include certain characteristics, such as one or more of the parameters listed in Table 1 below, and / or specific parameters configured in the CG configuration for small data transmission.

[0203] Table 1

[0204]

[0205]

[0206]

[0207] In some embodiments, when at least some UL data associated with a radio bearer / logical channel becomes available and / or a BSR is triggered (e.g., when the UE is in the RRC_INACTIVE state), the UE may determine, for example, based on whether one or more of the CG configuration / resource characteristics satisfy a specific rule, whether to use the CG configuration / resources for UL data transmission (e.g., SDT) to trigger an SR, initiate an RA procedure (e.g., for SDT), and / or initiate an RRC connection recovery procedure. More specifically, the UE may determine whether there are valid / available UL resources for UL data transmission (e.g., SDT) in the RRC_INACTIVE state based on whether one or more of the CG configuration / resource characteristics satisfy a specific rule.

[0208] In some embodiments, the UE may be configured with a threshold to determine whether to use the CG configuration / resources for UL data transmission (e.g., SDT) to trigger SR, initiate a RA process (e.g., for SDT), and / or initiate an RRC connection recovery process by determining whether a characteristic value of the CG configuration / resource is above or below a threshold. In some embodiments, the UE may be configured with a threshold by the BS in different ways, such as through dedicated signaling (e.g., in an RRCRelease message with a suspension configuration, etc.), through broadcast system information (e.g., SIB1, other SI, small data specific system information, etc.), or through other signaling. In some embodiments, once the UE receives the configured threshold, the UE may replace the stored threshold (if any) with the received threshold. In some embodiments, the UE may release the configured threshold when the UE enters the RRC_CONNECTED or RRC_IDLE state from the RRC_INACTIVE state. In some embodiments, the UE may receive several different thresholds, and each of these thresholds may be associated with a characteristic of the CG configuration / resource (e.g., the payload size of the first CG configuration, the period of the first CG configuration, the number of repetitions of the first CG configuration, etc.).

[0209] In some embodiments, when the UE is in the RRC_INACTIVE state, the UE may be configured with a first CG configuration. If at least some UL data associated with the radio bearer / logical channel becomes available and / or a BSR is triggered (e.g., when the UE is in the RRC_INACTIVE state), the UE may determine whether to use the CG configuration / resources for UL data transmission (e.g., SDT) to trigger an SR, initiate an RA procedure (e.g., for SDT), and / or initiate an RRC connection recovery procedure based on whether the amount of data of the first CG configuration is lower than a threshold. If the amount of data of the first CG configuration is lower than a threshold, the UE may use the CG configuration / resources for UL data transmission (e.g., SDT). If the amount of data of the first CG configuration is higher than a threshold, the UE may trigger an SR, initiate an RA procedure, and / or initiate an RRC connection recovery procedure. More specifically, if the amount of data of the first CG configuration is lower than a threshold, the UE may determine that there are valid / available UL resources for UL data transmission in the RRC_INACTIVE state.

[0210] In some embodiments, when the UE is in the RRC_INACTIVE state, the UE may be configured with a first CG configuration. If at least some UL data associated with the radio bearer / logical channel becomes available and / or a BSR is triggered (e.g., when the UE is in the RRC_INACTIVE state), the UE may determine whether to use the CG configuration / resources for UL data transmission (e.g., SDT) to trigger an SR, initiate an RA procedure (e.g., for SDT), and / or initiate an RRC connection recovery procedure, for example, based on whether the periodicity of the first CG configuration is lower than (or equal to) a threshold. If the periodicity of the first CG configuration is higher than the threshold, the UE may trigger an SR, initiate an RA procedure, and / or initiate an RRC connection recovery procedure. More specifically, when the periodicity of the first CG configuration is lower than the threshold, the UE may determine that there are valid / available UL resources for UL data transmission in the RRC_INACTIVE state.

[0211] In some embodiments, when the UE is in the RRC_INACTIVE state, the UE may be configured with a first CG configuration. If at least some UL data associated with the radio bearer / logical channel becomes available and / or a BSR is triggered (e.g., when the UE is in the RRC_INACTIVE state), the UE may determine, for example, based on whether the number of repetitions of the first CG configuration is higher / lower than a threshold, whether to use the CG configuration / resources for UL data transmission (e.g., SDT) to trigger an SR, initiate an RA procedure (e.g., for SDT), and / or initiate an RRC connection recovery procedure. If the number of repetitions of the first CG configuration is not higher than the threshold, the UE may trigger an SR, initiate an RA procedure, and / or initiate an RRC connection recovery procedure. More specifically, when the number of repetitions of the first CG configuration is higher than the threshold, the UE may determine that there are valid / available UL resources for UL data transmission in the RRC_INACTIVE state.

[0212] In some embodiments, the UE may be configured with a timer associated with the CG configuration, wherein the timer may be used to indicate whether the associated CG configuration / resources (e.g., for (new) transmission) are valid / available. For example, based on a running timer, the UE may determine that the associated CG configuration / resources (e.g., for (new) transmission) may be valid / available. In some embodiments, when the timer is not running, the UE may determine that the associated CG configuration / resources (e.g., for (new) transmission) are invalid / unavailable. In some embodiments, the UE may be configured with a timer by the NW via dedicated signaling (e.g., in an RRCRelease message with an abort configuration), in broadcast system information (e.g., SIB1, other SI, small data specific system information), etc.

[0213] In some embodiments, if the timer is running and the UE (in RRC_INACTIVE state) receives a configuration for the timer from the NW, the UE may ignore or may apply the configuration of the timer. In some embodiments, the UE may release / stop the timer when the UE enters the RRC_CONNECTED or RRC_IDLE state from the RRC_INACTIVE state. In some embodiments, the UE may (re)start the timer when it receives the configuration for the timer. For example, the UE may (re)start the timer when it receives the configuration for the timer via dedicated signaling (e.g., an RRC release message). In some embodiments, the UE may (re)start the timer when it receives a CG configuration. In some embodiments, the UE may receive configurations for several timers, each of which may be associated with one of the aCG configurations. In some embodiments, the UE may receive a configuration for a timer that is associated with all CG configurations of the UE.

[0214] In some embodiments, when the UE is in the RRC_INACTIVE state, the UE may be configured with a first CG configuration. If at least some UL data associated with the radio bearer / logical channel becomes available and / or a BSR is triggered (e.g., when the UE is in the RRC_INACTIVE state), the UE may determine, for example, based on whether a timer associated with the CG configuration is running, whether to use the CG configuration / resources for UL data transmission (e.g., SDT) to trigger an SR, initiate a RA procedure (e.g., for SDT), and / or initiate an RRC connection recovery procedure. If the timer associated with the CG configuration is running, the UE may use the CG configuration / resources for UL data transmission (e.g., SDT). If the timer associated with the CG configuration is not running (or expires), the UE may trigger an SR, initiate a RA procedure, and / or initiate an RRC connection recovery procedure. More specifically, when the timer associated with the CG configuration is running, the UE may determine that there are valid / available UL resources for UL data transmission (e.g., SDT) in the RRC_INACTIVE state.

[0215] In some embodiments, the timer may be a CG validity timer or a TA timer. For example, the timer may be used to control the release / suspension / deactivation / validity of a configured authorization configuration / resource. More specifically, when the timer expires (e.g., reaches zero), the UE may determine that the associated CG configuration is invalid. If the timer expires and the associated CG configuration becomes invalid, the UE may release / suspend the CG configuration / resource. Subsequently, when the CG configuration is released / suspended, the UE may initiate an RA procedure with a 2-step RA type and / or a 4-step RA type for small data transmission. In some embodiments, the timer may be used to control whether the timing advance is valid.

[0216] In some embodiments, the timer may be a specific timer. The specific timer may be associated with a HARQ process. When the UE receives, for example, an UL grant or DL ​​allocation for the corresponding HARQ process, the specific timer may be (re)started. When, for example, an UL and / or DL ​​transmission is performed for the corresponding HARQ process, the specific timer may be (re)started. When, for example, the UE receives HARQ feedback for the corresponding HARQ process, the specific timer may be stopped.

[0217] In some embodiments, a timer may be associated with one or more CG configurations. For example, one timer may be associated with all CG configurations applied by the UE. In another example, each timer may be associated with a corresponding CG configuration applied by the UE.

[0218] Standards 1-3: Based on the LCP mapping standard.

[0219] The UE may be configured with one or more LCP mapping restrictions for (each) logical channel (e.g., when the UE is in RRC_INACTIVE state). LCP mapping restrictions may be used to map UL data from different LCHs to UL resources with different characteristics. For example, LCP mapping restrictions may be used to map UL data from different LCHs to different configured grant configurations in the RRC_INACTIVE state, e.g., via the allowedCG-List.

[0220] In some embodiments, if at least some UL data associated with a radio bearer / logical channel becomes available and / or a BSR is triggered (e.g., when the UE is in RRC_INACTIVE state), the UE may determine, for example, based on whether the logical channel satisfies LCP mapping restrictions, whether to use the CG configuration / resources for UL data transmission (e.g., SDT) to trigger an SR, initiate an RA procedure (e.g., for SDT), and / or initiate an RRC connection recovery procedure. More specifically, the UE may determine whether there are valid / available UL resources for UL data transmission (e.g., SDT) in the RRC_INACTIVE state based on whether the logical channel satisfies LCP mapping restrictions.

[0221] In some embodiments, when the UE is in the RRC_INACTIVE state, the UE may be configured with a first CG configuration, and the UE may be configured with LCP mapping restrictions for logical channels. If at least some UL data associated with the radio bearer / logical channel becomes available and / or a BSR is triggered (e.g., when the UE is in the RRC_INACTIVE state), the UE may determine that the logical channels used for the first CG resources (e.g., indicated by the first CG configuration) meet the LCP mapping restrictions. If the logical channels of the first CG resources (e.g., indicated by the first CG configuration) do not meet the LCP mapping restrictions, the UE may trigger an SR, initiate a RA procedure and / or initiate an RRC recovery procedure. More specifically, when the logical channels used for the first CG resources (e.g., indicated by the first CG configuration) meet the LCP mapping restrictions, the UE may determine that there are valid / available UL resources for UL data transmission in the RRC_INACTIVE state.

[0222] In some embodiments, LCP mapping restrictions may be indicated by different parameters. These parameters may include, but are not limited to, allowedSCS-List, which may set the subcarrier spacing allowed for transmission; maxPUSCH-Duration, which may set the maximum PUSCH duration allowed for transmission; configuredGrantType1Allowed, which may determine whether a configured Grant Type 1 can be used for transmission; and allowedServingCells, which may set the cells allowed for transmission.

[0223] In some embodiments, specific LCP mapping restrictions may be defined for UL data transmission in the RRC_INACTIVE state. For example, the NW may configure parameters to control, for example, via a flag, whether the LCH or CG can trigger a BSR, trigger an SR, and / or initiate an RA procedure.

[0224] Criteria 1-4: Transmission timing based on the next CG resource opportunity (or the starting symbol of transmission).

[0225] In some embodiments, the CG resources may include periodic UL resources (e.g., the period of the CG resources may be configured in the CG configuration). The UE may be able to determine the transmission timing of the next CG resource opportunity (or the starting symbol of the transmission). If at least some UL data associated with the radio bearer / logical channel becomes available and / or a BSR is triggered at a first timing (e.g., when the UE is in the RRC_INACTIVE state), the UE may determine whether to use the CG configuration / resources for UL data transmission (e.g., SDT) to trigger an SR, initiate an RA procedure (e.g., for SDT), and / or initiate an RRC connection recovery procedure, for example, based on the duration of the first timing and the transmission timing (or the starting symbol of the transmission) of the next resource opportunity.

[0226] In some embodiments, if the duration is longer than a first threshold, the UE may trigger an SR, initiate a RA procedure and / or initiate an RRC recovery procedure. More specifically, when the duration is shorter than the first threshold, the UE may determine that there are valid / available UL resources for UL data transmission in the RRC_INACTIVE state. In some embodiments, if the duration is lower than the first threshold, the UE may use a CG configuration / resource for UL data transmission (e.g., SDT). In some embodiments, the threshold (e.g., the first threshold) may be configured in different ways, as described in the present disclosure. For example, the threshold may be configured in a UL data transmission (e.g., SDT) configuration or a CG configuration, may be specified in a specification, may be configured via an RRC release message (with a suspension configuration), and so on. In some embodiments, the unit of the threshold may be a symbol, a time slot, a millisecond, and the like. In some embodiments, the value of the threshold may be associated with the capabilities of the UE.

[0227] In some embodiments, the NW may be configured with a threshold by the UE via dedicated signaling (e.g., in an RRCRelease message with abort configuration). In some embodiments, the UE may be configured with a threshold by the NW via broadcasted system information (e.g., in SIB1, other SI, small data specific system information).

[0228] Criteria 1-5: Based on whether Timing Advance (TA) (eg, for CG) is valid.

[0229] Some embodiments may utilize TA for UL (Layer 1) synchronization. In the RRC_INACTIVE state, the UE may maintain the TA (e.g., via a TA timer). For example, when the TA timer is running, the UE may determine that the TA is valid. The BS may be responsible for maintaining the TA to maintain UL (Layer 1) synchronization, for example, by updating the TA value using specific indications / signaling. If at least some UL data associated with the radio bearer / logical channel becomes available and / or a BSR is triggered (e.g., when the UE is in the RRC_INACTIVE state), the UE may determine whether to use the CG configuration / resources for UL data transmission (e.g., SDT) to trigger an SR, initiate a RA procedure (e.g., for SDT), and / or initiate an RRC connection recovery procedure, for example, based on whether the TA (e.g., for the CG) is valid (e.g., whether the TA timer is running).

[0230] In some embodiments, if the TA is considered invalid (e.g., the TA timer is not running), the UE may trigger an SR, initiate an RA procedure, and / or initiate an RRC connection recovery procedure. More specifically, when the TA is considered valid (e.g., the TA timer is running), the UE may determine that there are valid / available UL resources for UL data transmission (e.g., SDT) in the RRC_INACTIVE state. In some embodiments, if the TA is considered valid (e.g., the TA timer is running), the UE may use the CG configuration / resources for UL data transmission (e.g., SDT).

[0231] In some embodiments, the TA timer may be maintained only in the RRC_INACTIVE state. For example, the TA timer may be configured for a UE in the RRC_INACTIVE state (e.g., the configuration of the TA timer may be included in an RRC release message (e.g., with a suspend configuration), and / or may be configured in an UL data transmission (e.g., SDT) configuration (as described above and below), and / or may be configured in a CG configuration).

[0232] In some embodiments, the TA timer may include one or more parameters, such as timeAlignmentTimer (e.g., as configured in RRC_CONNECTED), and may be (re)started when the UE (successfully) transmits data via the configured granted UL resources in the RRC_INACTIVE state. Additionally, the TA timer may be (re)started when the UE receives an indication / signaling from the network, wherein the indication / signaling may include a response to the UL transmission via the configured granted UL resources. Such a response may be a NACK / ACK indication, which may indicate an unsuccessful / successful reception of the UL transmission via the configured granted UL resources. The TA timer may be (re)started when the UE receives an indication from the network, wherein the indication may be used to (re)configure / (re)initialize / activate the configured granted configuration / resources. In some embodiments, the TA timer may be (re)started when the UE receives an indication from the network, wherein the indication may be used to update the TA, such as a timing advance command MAC CE.

[0233] Additionally, in some embodiments, the TA timer may be (re)started when the UE receives an UL grant that may schedule UL resources for retransmitting a configured uplink grant when the UE is in RRC_INACTIVE state. The UE may receive such an UL grant on a PDCCH with a special RNTI provided by the network. The special RNTI may be configured in an information element (IE) such as configuredGrantConfig.

[0234] In some embodiments, the TA timer may be stopped when the UE initiates an RA procedure. In some embodiments, the timer may be stopped when the UE initiates an RRC connection recovery procedure. In some embodiments, the TA timer may be stopped when the UE enters the RRC_CONNECTED state and / or the RRC_IDLE state. Furthermore, the TA timer may be stopped upon receiving an indication from the NW to release / suspend / deactivate a configured grant configuration / resource.

[0235] In some embodiments, the TA timer may be stopped when the UE receives an RRC message (e.g., RRC establishment, RRC recovery, RRC reconfiguration, RRC reconfiguration with synchronization (sync), RRC release, RRC release with abort configuration, RRC reestablishment, RRC reject, MobilityFromNRCommand, etc.).

[0236] In some embodiments, the TA timer may be stopped when the CG configuration / resources used by the UE in the RRC_INACTIVE state have been reconfigured by, for example, the network. In some embodiments, the TA timer may be configured via an RRC release message (e.g., with a suspend configuration) or via a specific configuration for small data transmission (SDT).

[0237] Criteria 1-6: Based on the amount of (pending) UL data.

[0238] The UE may determine the amount of (pending) UL data (e.g., associated with a radio bearer / logical channel) according to a data amount calculation procedure, such as the data amount calculation procedure described in 3GPP TS 38.322 and / or TS 38.323. Alternatively, determining the amount of (pending) UL data may be the same as determining the buffer size for the BSR, such as that described in 3GPP TS 38.321. For example, the UE / MAC entity may determine the amount of UL data available for the radio bearer / logical channel according to the data amount calculation procedure in TS 38.322 and / or TS 38.323. Alternatively, determining the amount of pending UL data may be based on the data available across all radio bearers / logical channels and the total amount of data that has not yet been associated with the radio bearer / logical channel (e.g., after all MAC PDUs have been established). The (pending) UL data may include UL data available for transmission in one or more layers, such as the RLC layer, the PDCP layer, the SDAP layer, and / or the RRC layer. If at least some UL data associated with a radio bearer / logical channel becomes available and / or a BSR is triggered (e.g., when the UE is in RRC_INACTIVE state), the UE may determine, for example, based on the amount of (pending) UL data, whether to use the CG configuration / resources for UL data transmission (e.g., SDT) to trigger an SR, initiate an RA procedure (e.g., for SDT), and / or initiate an RRC connection recovery procedure. In some embodiments, a radio bearer / logical channel may be specifically configured for SDT.

[0239] In some embodiments, if the amount of (pending) UL data is above a threshold, the UE may trigger an SR, initiate an RA procedure, and / or initiate an RRC connection recovery procedure. In some embodiments, if the amount of (pending) UL data is not above a threshold, the UE may use the CG configuration / resources for UL data transmission (e.g., SDT). As described above, such a threshold may be configured in the UL data transmission (e.g., SDT) configuration and / or in the CG configuration and / or in the RRC release message (with abort configuration).

[0240] In some embodiments, the UE may be configured with a threshold by the NW via dedicated signaling (e.g., in an RRCRelease message with abort configuration) and / or via broadcasted system information (e.g., SIB1, other SI, small data specific system information), etc. In some embodiments, the UE may release the configured threshold when, for example, the UE enters the RRC_CONNECTED or RRC_IDLE state from the RRC_INACTIVE state. In some embodiments, the UE may receive several thresholds, each of which may be associated with one of the CG configurations.

[0241] In some embodiments, if the amount of (pending) UL data is higher than the payload size of the (all) CG configurations, the UE may trigger an SR, initiate a RA procedure and / or initiate an RRC connection recovery procedure. More specifically, if the (total) net payload size of (all) (next available) CG resources mapped to a specific LCH is smaller than the amount of (pending) UL data associated with the specific LCH, the UE may trigger an SR, initiate a RA procedure and / or initiate an RRC connection recovery procedure. In some embodiments, if the amount of (pending) UL data is higher than a threshold, the UE may trigger a buffer status report (BSR).

[0242] Criteria 1-7: Based on which radio bearer / LCH / LCG the data is associated with.

[0243] Each logical channel type can be defined by what type of information is transmitted through the corresponding logical channel. Logical channels can be divided into different types, such as control channels and traffic channels. Control channels can be used to transmit control plane information / data. For example, the Broadcast Control Channel (BCCH) is a downlink channel used to broadcast system control information. The Paging Control Channel (PCCH) is a downlink channel that carries paging messages. The Common Control Channel (CCCH) is a channel used to transmit control information between the UE and the network. The CCCH is used for UEs that do not have an RRC connection with the network. The Dedicated Control Channel (DCCH) is a point-to-point bidirectional channel that transmits dedicated control information between the UE and the network and is used by UEs with an RRC connection. In the uplink, different connections between logical channels and transport channels. The CCCH can be mapped to the UL-SCH. The DCCH can be mapped to the UL-SCH. The DTCH can be mapped to the UL-SCH.

[0244] In some embodiments, the UE may be configured (e.g., via rlc-BearerToAddModList) with one or more logical channels, corresponding RLC entities, and their association with radio bearers. Each logical channel may have its own identity. The IE LogicalChannelIdentity may be used to identify the logical channel (LogicalChannelConfig) and the corresponding RLC bearer (RLC-BearerConfig).

[0245] For example, each logical channel can be assigned to an LCG using a logicalChannelGroup. More specifically, one or more logical channels (or LCH lists) can be assigned to a specific LCG, where the LCHs (or LCH lists) in the LCG can be used for UL data transmission in the RRC_INACTIVE state. An LCH (or a list of LCHs) can be associated with a specific SRB / DRB, where the specific SRB / DRB can be configured for SDT. When the UE initiates an SDT process and / or when the RRC state of the UE switches to the RRC_INACTIVE state (e.g., by receiving an RRC release with an abort configuration), the specific SRB / DRB can be restored. The LCH / LCG (identity) (or LCH list) can be configured in the UL data transmission (e.g., SDT) configuration. In some embodiments, if at least some UL data associated with a radio bearer / logical channel becomes available and / or a BSR is triggered (e.g., when the UE is in RRC_INACTIVE state), the UE may determine, for example, based on which LCH / LCG / radio bearer the UL data is associated with, whether to trigger an SR, initiate a RA procedure (e.g., for SDT), and / or initiate an RRC connection recovery procedure using a CG configuration / resource for UL data transmission (e.g., SDT).

[0246] In some embodiments, if UL data associated with a first radio bearer / logical channel becomes available and / or a BSR is triggered by the first logical channel (e.g., when the UE is in the RRC_INACTIVE state), the UE may trigger an SR, initiate an RA procedure, and / or initiate an RRC connection recovery procedure. Conversely, if UL data associated with a second radio bearer / logical channel becomes available and / or a BSR is triggered by the second logical channel (e.g., when the UE is in the RRC_INACTIVE state), the UE may not trigger an SR, may not initiate an RA procedure, and / or may not initiate an RRC connection recovery procedure, for example, if the UE is configured with a CG configuration and / or the CG is initialized / activated in the RRC_INACTIVE state.

[0247] In some embodiments, if UL data associated with a first radio bearer / logical channel allocated to a first LCG becomes available and / or a BSR is triggered by the first logical channel (e.g., when the UE is in the RRC_INACTIVE state), the UE may trigger an SR, initiate an RA procedure, and / or initiate an RRC connection recovery procedure. Conversely, if UL data associated with a second radio bearer / logical channel allocated to an LCG becomes available and / or a BSR is triggered by the second logical channel (when the UE is in the RRC_INACTIVE state), the UE may not trigger an SR, may not initiate an RA procedure, and / or may not initiate an RRC connection recovery procedure, for example, when the UE is configured with a CG configuration and / or the CG is initialized in the RRC_INACTIVE state. More specifically, the LCG may be a specific LCG (e.g., LCG 0) used for UL data transmission (e.g., SDT) in the RRC_INACTIVE state.

[0248] In some embodiments, if UL data associated with a first radio channel (associated with a first radio bearer) becomes available and / or a BSR is triggered by a first logical channel (when the UE is in an RRC_INACTIVE state), the UE may trigger an SR, initiate an RA procedure, and / or initiate an RRC connection recovery procedure. On the other hand, if UL data associated with a second logical channel (associated with a second radio bearer) becomes available and / or a BSR is triggered by a second logical channel (when the UE is in an RRC_INACTIVE state), the UE may not trigger an SR, may not initiate an RA procedure, and / or may not initiate an RRC connection recovery procedure.

[0249] In some embodiments, the first logical channel may be a logical channel with a specific priority (e.g., the highest priority or above a threshold). For example, if the specific priority of the logical channel is above / below the threshold, the UE may trigger an SR, initiate an RA procedure, and / or initiate an RRC connection recovery procedure, for example, when the UE is configured with a CG configuration and / or the CG configuration is initialized / activated in the RRC_INACTIVE state.

[0250] In some embodiments, the first logical channel may be associated with a specific logical channel identifier. For example, if the identifier of the specific logical channel (e.g., an index value assigned to the identifier) ​​is higher than / lower than a threshold, the UE may trigger an SR, initiate an RA procedure, and / or initiate an RRC connection recovery procedure.

[0251] In some embodiments, the first logical channel may be a CCCH. In some embodiments, the threshold may be configured in the LogicalChannelConfig, in the UL data transmission (e.g., SDT) configuration (as described above), in the CG configuration, and / or via an RRC release message (with an abort configuration). In some embodiments, if UL data associated with the radio bearer / logical channel becomes available and / or a BSR is triggered by the first logical channel (when the UE is in the RRC_INACTIVE state), the UE may determine, for example, based on a specific IE, whether to use the CG configuration / resources for UL data transmission (e.g., SDT) to trigger an SR, initiate an RA procedure (e.g., for SDT), and / or initiate an RRC connection recovery procedure. More specifically, the UE may determine, based on the presence or value of a specific IE, whether to use the CG configuration / resources for UL data transmission (e.g., SDT) to trigger an SR, initiate an RA procedure (e.g., for SDT), and / or initiate an RRC connection recovery procedure. For example, if the specific IE exists (and has a value of "TRUE" or "1"), the UE may trigger an SR, initiate an RA procedure, and / or initiate an RRC connection recovery procedure. In some implementations, a specific IE may be configured per logical channel (eg, configured for a first logical channel), per radio bearer, per serving cell, per MAC entity, and the like.

[0252] Criteria 1-8: Based on whether a specific process has been triggered (either pending or in progress).

[0253] In some implementations, the specific procedure may be a procedure for generating specific information (e.g., MAC CE). For example, the specific procedure may be called BSR, SR, RA, SDT, BFR, etc. When the specific procedure is triggered (rather than canceled), the UE may generate the specific information if UL resources are available to accommodate the specific information (plus its subtitle).

[0254] The specific process may be an RRC process, such as RRC connection establishment, RRC connection re-establishment, RRC connection recovery procedure, cell (re)selection, RNA update, tracking area update, SDT process, etc.

[0255] The specific process may be a process for generating information in the RRC_INACTIVE state. For example, the information may include an indication of the UE's buffer status, the amount of (pending) UL data, the preferred RRC state, certain UE assistance information, UE context, UE ID, ACK / NACK information, (beam / SSB) measurement reports, etc.

[0256] In some embodiments, the UE may be configured with a first CG configuration (when the UE is in the RRC_INACTIVE state). If at least some UL data associated with the radio bearer / logical channel becomes available and / or a BSR is triggered (e.g., when the UE is in the RRC_INACTIVE state), the UE may determine, for example, based on whether a specific procedure is triggered (or pending or in progress) whether to use the CG configuration / resources for UL data transmission (e.g., SDT) to trigger an SR, initiate an RA procedure (e.g., for SDT), and / or initiate an RRC connection recovery procedure. If the specific procedure is triggered (or pending or in progress), the UE may or may not trigger an SR, may or may not initiate an RA procedure, and / or may or may not initiate an RRC connection recovery procedure. More specifically, the UE may determine whether there are valid / available UL resources for UL data transmission (e.g., SDT) in the RRC_INACTIVE state based on whether the specific procedure is triggered (or pending or in progress).

[0257] Criteria 1-9: Based on DL channel conditions / quality

[0258] In some embodiments, the UE may perform a measurement procedure on a DL reference signal (e.g., SSB / CSI-RS) to determine the condition / quality of the DL channel (e.g., based on measurement results such as RSRP, RSRQ, RSSI, SINR, etc.). More specifically, the condition / quality of the DL channel may be measured / evaluated based on criteria for cell (re)selection.

[0259] In some embodiments, the UE may be configured with a first CG configuration (when the UE is in the RRC_INACTIVE state). If at least some UL data associated with the radio bearer / logical channel becomes available and / or a BSR is triggered (e.g., when the UE is in the RRC_INACTIVE state), the UE may determine, for example based on the condition / quality of the DL channel, whether to use the CG configuration / resources for UL data transmission (e.g., SDT) to trigger an SR, initiate an RA procedure (e.g., for SDT), and / or initiate an RRC connection recovery procedure.

[0260] In some embodiments, if the DL channel condition / quality falls below a first threshold, e.g., the SSB / CSI-RS with RSRP falls below an RSRP threshold, the UE may trigger an SR, initiate an RA procedure, and / or initiate an RRC connection recovery procedure. In some embodiments, if the DL channel condition / quality changes above a second threshold, e.g., the current RSRP compared to a stored / previous RSRP is above an RSRP threshold, the UE may trigger an SR, initiate an RA procedure, and / or initiate an RRC connection recovery procedure. The threshold may be configured in the UL data transmission (e.g., SDT) configuration (as described above), in the CG configuration, and / or via an RRC release message (with an abort configuration). In some embodiments, the UE may be configured with the threshold by the NW via dedicated signaling (e.g., in an RRC release message with an abort configuration) and / or via broadcast system information (e.g., SIB1, other SI, small data specific system information), etc. In some embodiments, the UE may release the configured threshold when, for example, the UE enters the RRC_CONNECTED or RRC_IDLE state from the RRC_INACTIVE state. In some embodiments, the UE may receive several thresholds, each of which may be associated with one of the CG configurations.

[0261] Criteria 1-10: Based on whether a transmission (eg, via a configured authorization) has failed multiple times, eg, within a time period.

[0262] In some embodiments, the UE may maintain a counter to count the number of times that an UL (or DL) transmission (e.g., performed via CG resources or other UL resources) has failed (e.g., transmission). For example, the UE may be configured with a first CG configuration (when the UE is in the RRC_INACTIVE state). If at least some UL data associated with the radio bearer / logical channel becomes available and / or a BSR is triggered (e.g., when the UE is in the RRC_INACTIVE state), the UE may determine whether to use the CG configuration / resources for UL data transmission (e.g., SDT) to trigger an SR, initiate an RA procedure (e.g., for SDT), and / or initiate an RRC connection recovery procedure, for example, based on whether the number indicated by the counter reaches a specific value (e.g., a maximum value that can be configured by the BS). In some embodiments, a counter may be incremented when the UE does not successfully transmit an UL (or DL) transmission (e.g., via configured granted resources or other UL resources), e.g., due to no data arrival, or due to poor channel conditions / quality, etc., when the UE does not receive an ACK for the UL transmission (e.g., within a time window), when the UE does not transmit (or when the UE skips) an UL transmission (e.g., via configured granted resources or other UL resources).

[0263] In some embodiments, the counter may be associated with one or more of the configured grant configurations. Alternatively, each CG configuration may be associated with a separate counter. In some embodiments, the counter may be reset when the UE triggers an SR, initiates a RA procedure and / or initiates an RRC connection recovery procedure. In some embodiments, the counter may be reset when the UE successfully transmits a (UL / DL) transmission (e.g., via configured grant resources or other UL resources). In some embodiments, the counter may be reset when the UE receives an indication from the network (e.g., the indication may be a response to a UL transmission). In some embodiments, the counter may be reset when the UE triggers and / or transmits an SR. In some embodiments, the counter may be reset when a timer (e.g., a TA timer, a CG timer, a specific timer (as described above)) expires.

[0264] In some implementations, a counter may be maintained per HARQ process. When the UE performs a (re)transmission on a HARQ process, the counter associated with the HARQ process may be incremented. Alternatively, when the UE receives a schedule for (re)transmission of the HARQ process, the counter associated with the HARQ process may be incremented.

[0265] In some embodiments, the value of the counter may be configured in the UL data transmission (e.g., SDT) configuration, CG configuration, and / or RRC release message (with abort configuration). In some embodiments, the UE may be configured with the value of the counter by the NW through dedicated signaling (e.g., in an RRC Release message with abort configuration) and / or through broadcast system information (e.g., SIB1, other SI, small data specific system information), etc. In some embodiments, when the UE enters the RRC_CONNECTED or RRC_IDLE state, for example from the RRC_INACTIVE state, the UE may release the configured value and / or reset the counter.

[0266] In some embodiments, the UE may be configured with a timer / window to determine whether an UL / DL transmission has been successfully transmitted during a particular time period. The timer may continue to run when the DL / UL transmission has not been successfully transmitted, for example, no ACK / NACK response has been received for the UL transmission. When the UE successfully transmits the UL / DL transmission (e.g., through configured granted resources or other resources), for example, an ACK response has been received for the UL transmission, the timer may be (re)started. In some embodiments, the timer may be (re)started when the UE receives an indication from the network (e.g., where the indication may be a response to a UL data transmission). If the timer expires, the UE may not be able to use the CG configuration for UL data transmission (e.g., SDT), and the UE may release the CG configuration / resources.

[0267] In some embodiments, the UE may be configured with a first CG configuration (when the UE is in the RRC_INACTIVE state). If at least some UL data associated with the radio bearer / logical channel becomes available and / or a BSR is triggered (e.g., when the UE is in the RRC_INACTIVE state), the UE may determine, for example, whether a timer is running, whether to use the CG configuration / resources for UL data transmission (e.g., SDT) to trigger an SR, initiate an RA procedure (e.g., for SDT), and / or initiate an RRC connection recovery procedure. For example, when the timer is running, the UE may determine to use the CG configuration / resources for UL data transmission (e.g., SDT). For example, when the timer is not running or the timer expires, the UE may determine to trigger an SR, initiate an RA procedure, and / or initiate an RRC connection recovery procedure.

[0268] In some embodiments, one or more of the radio bearers / logical channels configured for the UE may be further configured with certain specific masks / flags. In some such embodiments, radio bearers / logical channels configured with such masks / flags may trigger a BSR. In other words, only radio bearers / logical channels configured with such masks / flags may transmit small data using the RA procedure (e.g., triggered by a BSR).

[0269] In some embodiments, the timer may be a data inactivity timer (e.g., as described in 3GPP TS 38.321). The timer may be (re)started when the UE / MAC entity receives data for the LCH (e.g., MAC SDU) from upper layers, and / or when the UE transmits data for the LCH (e.g., MAC PDU). Upon expiration of the timer, the UE may release the CG configuration, trigger an SR, initiate an RA procedure, and / or initiate an RRC connection recovery procedure. In some embodiments, the UE may further determine whether to use the CG configuration / resources for UL data transmission (e.g., SDT) to trigger an SR, initiate an RA procedure (e.g., for SDT), and / or initiate an RRC connection recovery procedure, for example, based on whether the UL resources are (or are not) able to accommodate specific information (e.g., MAC CE or data).

[0270] Select RA procedure with 2-step or 4-step RA type for UL / small data transmission in RRC_INACTIVE state

[0271] As described above, two types of random access procedures may be supported / configured for the UE, which may be a 4-step RA type that may include MSG 1 / MSG 2 / MSG 3 / MSG 4, and a 2-step RA type that may include MSG A / MSG B.

[0272] In some embodiments, the UE may be configured with only RACH resources (e.g., no CG configuration / resources are configured at the UE), or there may be no valid / available CG resources for transmission, or the UE may determine not to use CG resources, for example, based on the above criteria. In some such embodiments, when at least some UL data associated with the radio bearer / logical channel becomes available and / or a BSR is triggered (e.g., when the UE is in RRC_INACTIVE state), the UE may trigger an SR, initiate a RA procedure, initiate an RRC connection recovery procedure, and / or select / set an RA type (e.g., a 2-step RA type or a 4-step RA type) to be used for the RA procedure.

[0273] For example, when initiating an RA procedure (e.g., when the UE is in the RRC_INACTIVE state), one or more of the following alternatives may be applied to select a 2-step RA type or a 4-step RA type for the initiated / ongoing RA procedure. It should be noted that in some embodiments, any number of the following alternatives may be combined to determine the RA type selected for the RA procedure.

[0274] Criterion 2-1: Based on the amount of (pending) UL data.

[0275] In some embodiments, when the UE (in RRC_INACTIVE state) initiates an RA procedure, if the amount of (pending) UL data is above a threshold, the UE may select a 4-step or 2-step RA type when initiating the RA procedure. In some embodiments, the threshold may be associated with the payload size of the PUSCH resources for MSG A.

[0276] Criterion 2-2: Based on the preamble and / or payload size of the PUSCH resources for MSG A.

[0277] In some embodiments, the UE may be configured with a specific preamble (e.g., preamble A or preamble B) that may be associated with a specific payload size of the PUSCH resources used for MSGA. For example, a first preamble may be mapped to a first size of the PUSCH resources used for MSGA, while a second preamble may be mapped to a second size of the PUSCH resources used for MSGA.

[0278] In some embodiments, when the UE initiates the RA procedure (e.g., when the UE is in the RRC_INACTIVE state), if a specific preamble group is configured (e.g., for 2-step RA), the UE may select the 2-step RA type. Otherwise, the UE may select the 4-step RA type.

[0279] In some embodiments, when the UE initiates the RA procedure (e.g., when the UE is in RRC_INACTIVE state), the UE may select a 2-step RA type if a specific payload size is configured for the PUSCH resource for MSG A. Otherwise, the UE may select a 4-step RA type.

[0280] In some embodiments, when the UE initiates an RA procedure (e.g., when the UE is in the RRC_INACTIVE state), if a specific payload size is greater than a threshold, the UE may select a 2-step RA type. Otherwise, the UE may select a 4-step RA type.

[0281] Criteria 2-3: Based on which LCH / LCG / radio bearer the data is associated with and / or which LCH / LCG / radio bearer triggers the BSR / SR / RA.

[0282] In some embodiments, when the UE initiates the RA procedure (e.g., when the UE is in RRC_INACTIVE state), if UL data associated with the first LCH / LCG / RB becomes available and / or BSR / SR / RA has been triggered by the first LCH / LCG / RB (e.g., when the UE is in RRC_INACTIVE state), the UE may select the 2-step RA type. Otherwise, the UE may select the 4-step RA type.

[0283] In some embodiments, when the UE initiates the RA procedure (e.g., when the UE is in the RRC_INACTIVE state), if UL data associated with the first radio bearer / logical channel allocated to the first LCG becomes available and / or a BSR / SR / RA has been triggered by the first radio bearer / logical channel (when the UE is in the RRC_INACTIVE state), the UE may select the 2-step RA type. Otherwise, the UE may select the 4-step RA type.

[0284] In some embodiments, when the UE initiates the RA procedure (e.g., when the UE is in the RRC_INACTIVE state), if UL data associated with the first logical channel (associated with the first radio bearer) becomes available and / or a BSR has been triggered by the first logical channel (e.g., when the UE is in the RRC_INACTIVE state), the UE may select the 2-step RA type. Otherwise, the UE may select the 4-step RA type.

[0285] Figure 3 3 is a flow chart illustrating a method (or process) 300 performed by a UE to transmit uplink (UL) data to a base station (BS) when the UE is in an RRC_INACTIVE state according to an exemplary embodiment of the present application. In some embodiments, the UE may transmit UL data (e.g., small data) associated with a specific radio bearer (RB) (e.g., a DRB or SRB). In some such embodiments, the specific RB may be configured for small data transmission. The specific RB may be restored when the UE is in the RRC_INACTIVE state, for example, when the UE initiates an SDT procedure.

[0286] As shown, process 300 may begin with the following steps: At 310, an RRC release message is received from a base station (BS) when the UE is in the RRC_CONNECTED state. The RRC release message may include configuration / IEs, such as at least a configured grant (CG) configuration and a time alignment (TA) timer (e.g., a value of the TA timer). In some embodiments of the present invention, the RRC release message may also include an information element (IE), such as a suspendConfig parameter, which may indicate that the UE is transitioning from the RRC_CONNECTED state to the RRC_INACTIVE state, for example.

[0287] After receiving the RRC release message, the process 300 may cause the UE to transition from the RRC_CONNECTED state to the RRC_INACTIVE state at 320, for example. At 330, the process 300 may start or restart the TA timer in response to receiving the RRC release message, in response to receiving the CG configuration, and / or in response to receiving the configuration of the TA timer. As described above, in some embodiments, the TA timer may be configured for use by the UE in the RRC_INACTIVE state. For example, when the UE receives a specific indication to update the timing advance (e.g., a timing advance command), the UE may apply the timing advance command and (re)start the TA timer. The timing advance command may be used to update the timing advance value for UL (Layer 1) synchronization.

[0288] At 340, process 300 may transmit UL data (e.g., small data) via the UL resources configured by the CG configuration when the UE is in the RRC_INACTIVE state. The process may transmit the UL data after determining that a set of one or more criteria are met. In some embodiments, the set of criteria may include at least a criterion for a running TA timer. When the TA timer is running (e.g., not expired or has not reached zero), the UE may determine that the TA is valid and continue to transmit UL data. In some embodiments, if at least one of the set of criteria is not met, for example, if the TA timer expires (or is not running), the UE may initiate a RA process. The process may then end.

[0289] In some embodiments, another criterion in the set of criteria may include the amount of UL data being below a threshold. In some such embodiments, when the amount of UL data is above the threshold, the process may initiate an RRC connection recovery procedure. In some embodiments, the amount of data may be determined based on the total amount of UL data associated with a particular RB.

[0290] In some embodiments, the set of criteria may also include criteria for synchronization signal blocks (SSBs) with reference signal received power (RSRP) above a threshold. The set of criteria may also include criteria for specific timers (except the TA timer) that are running, which are started or restarted when the UE transmits UL data via UL resources.

[0291] Figure 4 1 shows a block diagram of a node for wireless communication according to an exemplary embodiment of the present application. Figure 4As shown, the node 400 may include a transceiver 420, a processor 426, a memory 428, one or more presentation components 434, and at least one antenna 436. The node 400 may also include a radio frequency (RF) spectrum band module, a base station communication module, a network communication module, a system communication management module, an input / output (I / O) port, an I / O component, and a power supply (in the Figure 4 Each of these components may communicate with each other, directly or indirectly, via one or more buses 440.

[0292] The transceiver 420 having a transmitter 422 and a receiver 424 can be configured to transmit and / or receive time and / or frequency resource partitioning information. In some embodiments, the transceiver 420 can be configured to transmit in different types of subframes and time slots, including but not limited to usable, unusable, and flexibly usable subframe and time slot formats. The transceiver 420 can be configured to receive data and control signals.

[0293] Node 400 may include a variety of computer-readable media. Computer-readable media can be any available media accessible by node 400 and include both volatile and non-volatile media, removable and non-removable media. By way of example and not limitation, computer-readable media may include computer storage media and communication media. Computer storage media include both volatile and non-volatile media, removable and non-removable media, and can be implemented in any method or technology for information such as computer-readable instructions, data structures, program modules, or other data.

[0294] Computer storage media include RAM, ROM, EEPROM, flash memory (or other storage technology), CD-ROM, Digital Versatile Disk (DVD) or other optical disk storage devices, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices. Computer storage media do not include propagating data signals. Communication media typically contain computer-readable instructions, data structures, program modules or other data in a modulated data signal (such as a carrier wave or other transport mechanism), and include any information delivery media. The term "modulated data signal" refers to a signal having one or more characteristics set or changed in such a way as to encode information in the signal. By way of example, and not limitation, communication media include wired media (such as a wired network or a direct wired connection) and wireless media (such as acoustic, RF, infrared and other wireless media). Any combination of the above media should also be included within the scope of computer-readable media.

[0295] The memory 428 may include computer storage media in the form of volatile and / or non-volatile memory. The memory 428 may be removable, non-removable, or a combination thereof. For example, the memory may include solid-state memory, a hard drive, an optical drive, etc. Figure 4 As shown, the memory 428 may store computer-readable, computer-executable instructions 432 (e.g., software code) that, when executed, are configured to cause the processor 426 (e.g., processing circuitry) to perform various functions described herein, such as with reference to Figures 1 to 4 Alternatively, instructions 432 may not be directly executable by processor 426, but may be configured to cause node 400 (eg, when compiled and executed) to perform various functions described herein.

[0296] Processor 426 may include an intelligent hardware device, such as a central processing unit (CPU), a microcontroller, an ASIC, or the like. Processor 426 may also include memory. Processor 426 may process data 430 and instructions 432 received from memory 428, as well as information transmitted through transceiver 420, the baseband communication module, and / or the network communication module. Processor 426 may also process information to be transmitted to transceiver 420 for transmission to the NW communication module via antenna 436 for transmission to the CN.

[0297] One or more presentation components 434 present data indications to a person or other device. For example, one or more presentation components 504 include a display device, a speaker, a printing component, a vibration component, etc.

[0298] From the above description, it has been shown that, without departing from the scope of the concepts described in this application, various techniques can be used to realize these concepts. In addition, although concepts have been described with specific reference to certain embodiments, it will be appreciated by those skilled in the art that, without departing from the scope of those concepts, changes can be made in form and detail. Therefore, the described embodiments should be considered to be illustrative and not restrictive in all respects. It should also be understood that, although the application is not limited to the specific embodiments described above, many rearrangements, modifications, and replacements are possible without departing from the scope of this disclosure.

Claims

1. A method for transmitting uplink (UL) data associated with a specific radio bearer (RB) by a user equipment (UE), the method comprising: When in a radio resource control RRC_CONNECTED state, receiving an RRC release message from a base station BS, the RRC release message including at least a configured authorized CG configuration and a value of a time alignment TA timer; In response to receiving the RRC release message, transitioning to the RRC_INACTIVE state; In response to receiving the RRC release message, starting or restarting the TA timer; as well as After determining that a set of one or more criteria is met, the UL data is transmitted via the UL resources configured by the CG configuration when in the RRC_INACTIVE state, and the set of criteria includes at least a criterion for the TA timer being running.

2. The method of claim 1, further comprising: In response to receiving an indication to update the timing advance from the BS while in the RRC_INACTIVE state, starting or restarting the TA timer.

3. The method of claim 1 , further comprising: When it is determined that one of the criteria set is not satisfied, a random access RA procedure is initiated.

4. The method according to claim 1, wherein The set of criteria also includes a criterion for the data amount of the UL data to be below a threshold.

5. The method of claim 4, further comprising: When the data amount of the UL data is higher than the threshold, an RRC connection recovery process is initiated.

6. The method according to claim 5, wherein The data amount is determined based on a total amount of the UL data associated with the specific RB.

7. The method according to claim 1, wherein The set of criteria also includes a criterion for a synchronization signal block SSB having a reference signal received power RSRP above a threshold.

8. The method according to claim 1, wherein The set of criteria further includes a criterion for a specific timer that is running, and when the UE transmits the UL data via the UL resource, the specific timer is started or restarted.

9. The method according to claim 1, wherein The specific RB is configured for small data transmission.

10. The method according to claim 1, wherein The RRC release message also includes an information element IE suspendConfig .

11. A user equipment (UE), comprising: one or more non-transitory computer-readable media having computer-executable instructions for transmitting uplink (UL) data associated with a particular radio bearer (RB); as well as at least one processor coupled to the one or more non-transitory computer-readable media and configured to execute the computer-executable instructions to: When in a radio resource control RRC_CONNECTED state, receiving an RRC release message from a base station BS, the RRC release message including at least a configured authorized CG configuration and a value of a time alignment TA timer; In response to receiving the RRC release message, transitioning to the RRC_INACTIVE state; In response to receiving the RRC release message, starting or restarting the TA timer; as well as After determining that a set of one or more criteria is met, the UL data is transmitted via the UL resources configured by the CG configuration when in the RRC_INACTIVE state, and the set of criteria includes at least a criterion for the TA timer being running.

12. The UE according to claim 11, wherein: The at least one processor is further configured to execute computer-executable instructions to: In response to receiving an indication to update the timing advance from the BS while in the RRC_INACTIVE state, starting or restarting the TA timer.

13. The UE according to claim 11, wherein: The at least one processor is further configured to execute computer-executable instructions to: When it is determined that one of the criteria set is not satisfied, a random access RA procedure is initiated.

14. The UE according to claim 11, wherein: The set of criteria also includes a criterion for the data amount of the UL data to be below a threshold.

15. The UE according to claim 14, wherein: The at least one processor is further configured to execute computer-executable instructions to: When the data amount of the UL data is higher than the threshold, an RRC connection recovery process is initiated.

16. The UE according to claim 15, wherein: The data amount is determined based on a total amount of the UL data associated with the specific RB.

17. The UE according to claim 11, wherein: The set of criteria also includes a criterion for a synchronization signal block SSB having a reference signal received power RSRP above a threshold.

18. The UE according to claim 11, wherein: The set of criteria further includes a criterion for a specific timer that is running, and when the UE transmits the UL data via the UL resource, the specific timer is started or restarted.

19. The UE according to claim 11, wherein: The specific RB is configured for small data transmission.

20. The UE according to claim 11, wherein The RRC release message also includes an information element IE suspendConfig .

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