Method and user equipment for access control in a wireless communication system - Patents.com

Abstract

Provided are a method and a UE for access control in a wireless communication system. The method, performed by the UE for access control, includes receiving a radio resource configuration from a serving cell while the UE is attempting to initiate an UL data transmission procedure with the serving cell during an RRC inactive state of the UE, and transmitting one or more UL packets to the serving cell based on the radio resource configuration when a plurality of conditions are met, including that the UL data transmission attempt is not prohibited by the serving cell and that the amount of pending UL data to be transmitted is less than or equal to a data amount threshold.

Description

[Technical field]

[0002] [Field] The present disclosure relates to wireless communications, and more particularly, to a method and user equipment (UE) for access control in a wireless communications system. [Background technology]

[0003] 〔background〕 With a significant increase in the number of connected devices and a rapid increase in user / network traffic volume, various efforts have been made to improve various aspects of wireless communication systems for next generation wireless communication systems, such as Fifth Generation (5G) New Radio (NR), by improving data speeds, latency, reliability, and mobility. Summary of the Invention The problem that disclosure aims to solve

[0004] The 5G NR system is designed to provide flexibility and configurability to optimize network services and types for a variety of use cases, such as enhanced mobile broadband (eMBB), massive machine type communications (mMTC), and ultra-reliable low latency communications (URLLC).

[0005] However, as the demand for wireless access continues to increase, further improvements in wireless communications are needed for next generation wireless communication systems. [Means for solving the problem]

[0006] The disclosure is directed to a method and user equipment for access control in a wireless communication system.

[0007] According to a first aspect of the present disclosure, a method is provided that is performed by a user equipment (UE) for access control, the method including receiving a radio resource configuration from a serving cell while the UE is attempting to initiate an uplink (UL) data transmission procedure with the serving cell during a radio resource control (RRC) inactive state of the UE, and transmitting one or more UL packets to the serving cell based on the radio resource configuration when a plurality of conditions are met, the plurality of conditions including that an uplink data transmission attempt is not prohibited by the serving cell, and that an amount of pending UL data to be transmitted is less than or equal to a data amount threshold.

[0008] In one embodiment of the first aspect, the UL data transmission procedure is a Random Access (RA) procedure triggered by the UE based on a radio resource configuration.

[0009] In another embodiment of the first aspect, the UL data transmission procedure includes accessing at least one UL configuration grant (UL-CG) via UE-specific control signaling based on a UL-CG configuration preconfigured by the serving cell.

[0010] Another embodiment of the first aspect further includes determining whether to access at least one UL-CG for a UL data transmission procedure based on a data volume threshold, and determining whether to initiate a random access (RA) procedure for the UL data transmission procedure based on the data volume threshold.

[0011] In one embodiment of the first aspect, the UE receives system information from a serving cell including a cell barring bit indicating that the serving cell is barred or the serving cell is barred (by the UE) for SDT procedures during a barring period determined by the UE based on a unified access control (UAC) mechanism.

[0012] In one embodiment of the first aspect, a UAC mechanism is executed by the UE for a UL data transmission procedure based on an access category associated with the UL data transmission procedure.

[0013] In another embodiment of the first aspect, the method further includes determining a prohibition period for a previous access attempt by the serving cell, the previous access attempt occurring earlier than an access attempt of the UE to initiate a UL data transmission procedure, and the previous access attempt and the access attempt of the UE to initiate a UL data transmission procedure belong to the same access category in the UAC mechanism.

[0014] Another embodiment of the first aspect further includes not performing another UAC mechanism for an access attempt of the UL data transmission procedure until the prohibition period has elapsed.

[0015] Another embodiment of the first aspect further includes receiving the data amount threshold via UE-specific RRC signaling or broadcasted system information.

[0016] Another embodiment of the first aspect further includes determining the amount of pending UL data by only considering pending data for UL data transmission during the RRC inactive state in all of a plurality of logical channels allowed by the serving cell.

[0017] According to a second aspect of the present disclosure, a UE for access control is provided. The UE comprises a memory and a processing circuit coupled to the memory. The processing circuit is configured to receive a radio resource configuration from a serving cell while the UE is attempting to initiate a UL data transmission procedure with the serving cell during an RRC inactive state of the UE, and transmit one or more UL packets to the serving cell based on the radio resource configuration when a plurality of conditions are met. The plurality of conditions include that an UL data transmission attempt is not prohibited by the serving cell and an amount of pending UL data to be transmitted is less than or equal to a data amount threshold.

[0018] In one embodiment of the second aspect, the radio resource configuration is a Random Access (RA) procedure triggered by the UE based on the radio resource configuration.

[0019] In another embodiment of the second aspect, the UL data transmission procedure includes accessing at least one UL configured grant (UL-CG) via UE-specific control signaling based on a UL-CG configuration preconfigured by the serving cell.

[0020] In another embodiment of the second aspect, the process circuit is further configured to determine whether to access at least one UL-CG for a UL data transmission procedure based on a data volume threshold, and to determine whether to initiate an RA procedure for the UL data transmission procedure based on the data volume threshold.

[0021] In one embodiment of the second aspect, if the UE receives system information from the serving cell including a cell barring bit indicating that the serving cell is barred, or the serving cell is barred for a barring period determined by the UE based on the outcome of a unified access control (UAC) mechanism, then the UL data transmission attempt is barred.

[0022] In one embodiment of the second aspect, a UAC mechanism is implemented by the UE for a UL data transmission procedure based on an access category (and / or access identity information) associated with the UL data transmission procedure.

[0023] In another embodiment of the second aspect, the process circuitry is further configured to determine a prohibition period for a previous access attempt using the serving cell, where the previous access attempt occurs earlier than an access attempt of the UE to initiate a UL data transmission procedure, and where the previous access attempt and the access attempt of the UE to initiate a UL data transmission procedure belong to the same access category in the UAC mechanism.

[0024] In another implementation of the second aspect, the process circuitry is further configured to not execute another UAC mechanism for an access attempt of the UL data transmission procedure until the prohibition period has elapsed.

[0025] In another embodiment of the second aspect, the data amount threshold is received via UE specific RRC signaling or via broadcasted system information.

[0026] In another embodiment of the second aspect, the serving cell is further configured to determine the amount of pending UL data only by considering pending data in one or more logical channels among a plurality of logical channels allowed by the serving cell for UL data transmission. [Brief description of the drawings]

[0027] The abbreviations in this application are defined as follows, and unless otherwise stated, the abbreviations have the following meanings: Abbreviation Full Name 3GPP 3rd Generation Partnership Project 5GC 5G Core ACK Acknowledgement AMF Access and Mobility Management Functions ARQ Automatic Repeat Request AS Access Layer BCCH Broadcast Control Channel BCH Broadcast Channel BFR Beam Failure Recovery BS base station BSR Buffer Status Report BWP Bandwidth Part CA Carrier Aggregation CBRA Contention-Based Random Access CFRA Contention Free Random Access CG Configured Grant CM Connection Management CN Core Network CP Control Plane C-RNTI Cell Radio Network Temporary Identifier CG-SDT Setting Small Data Transmission CS-RNTI Configured Scheduling Radio Network Temporary Identifier CSI-RS Channel State Information Reference Signal DC Dual Access DCI Downlink Control Information DL Downlink DRB Data Radio Bearer DRX Intermittent Reception HARQ Hybrid Automatic Repeat Request ID Identifier IE Information Elements I-RNTI Inactive Radio Network Temporary Identifier LCH Logical Channel LCG Logical Channel Group LCP Logical Channel Prioritization MAC Media Access Control MIB Master Information Block MSG Message NAS non-access layer NACK Negative Response NG-RAN Next Generation Radio Access Network NR new radio NW Network PCell Primary Cell PCCH Paging Control Channel PDCCH Physical Downlink Control Channel PDCP Packet Data Convergence Protocol PDU Protocol Data Unit PRACH Physical Random Access Channel PUCCH Physical uplink control channel PUSCH Physical Uplink Shared Channel PLMN Public Land Mobile Network QoS Quality of Service RA Random Access RA-SDT Random Access Small Data Transmission RACH Random Access Channel RAN Radio Access Network RB Radio Bearer Rel Release RLC Radio Line Control RNA RAN-based notification area RNTI Radio Network Temporary Identifier RRC Radio Resource Control RSRP reference signal received power SCell Secondary Cell SCG Secondary Cell Group SCS Subcarrier Spacing SDT Small Data Transmission SDU Service Data Unit SFN System Frame Number SI System Information SIB System Information Block SIB1 System Information Block Type 1 SINR Signal to Interference Plus Noise Ratio SLIV start and length indicator SNPN Standalone Private Network SR Scheduling Request SRB Signaling Radio Bearer SSB sync signal block S-TMSI SAE - Temporary Mobile Subscriber Identity SUL Auxiliary Uplink TA Timing Advance or Time Alignment TB Transport Block TAG Timing Advance Group TS Technical Specifications UAC Unified Access Control UE User Equipment UL Uplink UL-CG Uplink configured grant UP User Plane UPF User Plane Function Aspects of the present embodiment are best understood from the following detailed description when read in conjunction with the accompanying drawing figures. Various features are not drawn to scale. Dimensions of various features may be arbitrarily increased or decreased for clarity of discussion. [Figure 1] FIG. 1 is a schematic diagram illustrating a process for an access control mechanism while a UE is attempting to initiate an SDT procedure with a serving RAN according to one embodiment of the present disclosure. [Diagram 2] FIG. 2 illustrates an example of an RA-SDT procedure according to an embodiment of the present disclosure. [Diagram 3] FIG. 3 illustrates an example of a CG-SDT procedure according to an embodiment of the present disclosure. [Figure 4] FIG. 4 is a flow chart of a method for access control of an SDT according to one embodiment of the present disclosure. [Diagram 5] FIG. 5 illustrates a flowchart of a method for implementing a UAC mechanism for an SDT according to an implementation of the present disclosure. [Figure 6] FIG. 6 is a flowchart of a method of access control performed by a UE according to one embodiment of the present disclosure. [Figure 7] FIG. 7 illustrates a flow chart of a method for access control according to one embodiment of the present disclosure. [Figure 8] FIG. 8 illustrates a flowchart of a method for access control according to one embodiment of the present disclosure. [Figure 9] FIG. 9 is a block diagram illustrating a node for wireless communication according to an embodiment of the disclosure. MODE FOR CARRYING OUT THE DISCLOSURE

[0028] Detailed Description The following contains specific information related to the implementation of the present disclosure. The drawings and their accompanying detailed description are directed to embodiments only. However, the present disclosure is not limited to these implementations. Other variations and implementations of the present disclosure will be apparent to those skilled in the art.

[0029] Unless otherwise noted, like or corresponding elements between the drawings may be indicated by like or corresponding reference numerals. Further, the drawings and illustrations in this disclosure are generally not to scale and are not intended to correspond to actual relative dimensions.

[0030] For ease of consistency and understanding, similar features may be identified by the same numbers in the drawings (not shown in some examples), however, features in different embodiments may differ in other respects and are not intended to be narrowly limited to those shown in the drawings.

[0031] The phrases "in one embodiment" or "in some embodiments" may refer to one or more of the same or different embodiments, respectively. The term "coupled" is defined as directly or indirectly connected through intervening elements, and is not necessarily limited to a physical connection. The term "comprising" indicates an open-ended inclusion or membership in a disclosed combination, series, group, or equivalent, but is not necessarily limited thereto. The phrase "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." The terms "system" and "network" may be used interchangeably. The term "and / or" is only an association relationship to disclose related objects and represents that a three-way relationship may exist, such as A and / or B may indicate that A exists alone, A and B exist simultaneously, or B exists alone. "A and / or B and / or C" may represent that at least one of A, B, and C is present. The character " / " generally represents that related objects are in an "or" relationship.

[0032] For purposes of explanation and not limitation, specific details of functional entities, techniques, protocols, standards, etc. are set forth in order to provide an understanding of the disclosed technology. In other instances, detailed descriptions of well-known methods, techniques, systems, architectures, etc. are omitted so as not to obscure the present disclosure with unnecessary detail.

[0033] Those skilled in the art will readily recognize that any disclosed network function or algorithm may be performed by hardware, software, or a combination of software and hardware. The disclosed functions may correspond to modules, which may be software, hardware, firmware, or any combination thereof.

[0034] Software embodiments may include computer-executable instructions stored on a computer-readable medium, such as a memory or other type of storage device. One or more microprocessors or general-purpose computers having communications processing capabilities can be programmed with the corresponding computer-executable instructions to perform the disclosed network functions or algorithms.

[0035] A microprocessor or general-purpose computer may include the use of an application specific integrated circuit (ASIC), a programmable logic array, and / or one or more digital signal processors (DSPs). Although some of the disclosed embodiments are directed to software installed and executed on computer hardware, alternative embodiments implemented as firmware, or as hardware, or as a combination of hardware and software, are well within the scope of this disclosure. The computer-readable medium may include, but is 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), magnetic cassette, magnetic tape, magnetic disk storage device, or any other equivalent medium capable of storing computer-readable instructions.

[0036] A wireless communication network architecture, such as 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 (BS), at least one UE, and one or more that provide access within the network. The UE may communicate with a network, such as a Core Network (CN), an Evolved Packet Core (EPC) network, an Evolved Universal Terrestrial RAN (E-UTRAN), a Next Generation Core (NGC), a 5G Core (5GC), or the Internet, via the RAN established by the one or more BSs.

[0037] The UE may include, but is not limited to, a mobile station, a mobile UE or device, or a user communication radio UE. The UE may be a mobile radio device, including, but not limited to, a mobile phone, a tablet, a wearable device, a sensor, a vehicle, or a personal digital assistant (PDA) having wireless communication capabilities. The UE may be configured to receive and transmit signals over the air interface to one or more cells in the RAN.

[0038] The BS provides communication services according to at least a radio access technology (RAT) such as Worldwide Interoperability for Microwave Access (WiMAX), Global System for Mobile Communications (GSM) often referred to as 2G, Enhanced Data Rates for GSM (EDGE) RAN for GSM Evolution, General Packet Radio Service (GPRS), Universal Mobile Telecommunications System (UMTS) based on basic Wideband Code Division Multiple Access (W-CDMA) often referred to as 3G, High Speed ​​Packet Access (HSPA), LTE, LTE-A, 5GC, NR (often referred to as 5G), and / or LTE connected to LTE-A Pro (eLTE), although the scope of this disclosure is not limited to these protocols.

[0039] The BS 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 / GERAN, a Next Generation eNB (ng-eNB) in an evolved terrestrial radio access (E-UTRA) BS associated with 5GC, a Next Generation Node B (gNB) in 5G-RAN (or in a 5G Access Network (5G-AN)), or any other device capable of controlling wireless communications and managing radio resources in a cell. The BS may serve one or more UEs over an air interface.

[0040] The base station may provide radio coverage to a particular geographic area using a number of cells included in the radio base station, the base station may support the operation of cells, each of which is operable to serve at least one UE within its radio coverage.

[0041] Each cell (often referred to as a serving cell) may provide services to serve one or more UEs within its radio coverage such that each cell schedules downlink (DL) and optionally uplink (UL) resources to at least one UE within its radio coverage for DL ​​and optionally UL packet transmissions. A base station may communicate with one or more UEs in a wireless communication system via multiple cells.

[0042] A cell can allocate sidelink (SL) resources to support proximity services (ProSe), LTE SL services, LTE / NR sidelink communication services, LTE / NR sidelink discovery services, and / or LTE / NR Vehicle-to-Everything (V2X) services.

[0043] In NR, a packet transmission mechanism is introduced that enables a UE to perform data transmission in an RRC inactive state. Packet transmission is also referred to as "SDT (or small data transmission)" or "small packet transmission" in this disclosure. Thus, the terms "packet transmission", "SDT", and "small packet transmission" are interchangeable in this disclosure.

[0044] In some aspects of the present disclosure, (part of) the access control for small packet transmission may be performed in the RRC layer (or RRC entity). The RRC layer may instruct the MAC layer whether to enable (or disable) the MAC entity to deliver packets by using an RA procedure (e.g., 2-step / 4-step RA procedure) or by using one or more uplink configured permission settings. The UE may observe that the cell is "barred" by detecting that the value of the "CellBarred" bit changes from "not prohibited" to "Barred" (or vice versa). Some embodiments of the present disclosure provide a UE / RAN mechanism, while the CellBarring mechanism is taken into account in the (small) packet transmission mechanism. In some other aspects of the present disclosure, (part of) the access control for small packet transmission may be performed in the MAC layer (or MAC entity). The MAC layer may inform the RRC layer whether to enable (or disable) the MAC entity to deliver packets by using an RA procedure (e.g., 2-step / 4-step RA procedure) or by using one or more uplink configured permission settings. The UE can observe that a cell is "barred" by detecting that the value of the "CellBarred" bit changes from "non-barred" to "Barred" (or vice versa). Some embodiments of the present disclosure provide a UE / RAN mechanism while the CellBarring mechanism is taken into account in the (small) packet transmission mechanism.

[0045] In some aspects herein, during packet transmission via a 2-step / 4-step RA procedure, a UE may receive an RRCReject message from a serving cell. Some embodiments of the present disclosure provide a packet transmission mechanism that takes into account the transmission or reception of an RRCReject message.

[0046] In some aspects of the disclosure, a Unified Access Control (UAC) mechanism (e.g., UAC mechanism in 3GPP TS 38.331 or TS 38.304) may be performed at the MAC layer (e.g., in a MAC entity) or the RRC layer (e.g., in an RRC entity). The MAC layer may determine whether an RA procedure and associated pre-configured RA resources for a UE (e.g., a UE in an RRC Inactive state or an RRC Idle (i.e., RRC Idle) state) are applicable to the UE for small packet transmission and associated access category while an RRC message (e.g., an RRCResumeRequest message) is multiplexed with a pending UL packet. In some embodiments, a different access category for SDT may alternatively be determined when an RRC message (e.g., an RRCResumeRequest message) is not multiplexed with a UL packet during an SDT procedure (e.g., via an RRC-less small packet transmission procedure).

[0047] In some aspects of the present disclosure, some additional rules regarding RA prioritization for (small) packet transmissions are also provided.

[0048] In some aspects of the present disclosure, access control may be performed based on data volume.

[0049] In some embodiments, the UE may determine whether to initiate small packet transmission through a (2-step / 4-step) RA procedure or UL-CG configuration based on a (pre-configured) data volume threshold.

[0050] It should be noted that although the mechanisms described in this disclosure are mostly described with respect to UEs in an RRC inactive state, the mechanisms described may also be applicable to UEs in an RRC idle state.

[0051] In addition, the UE may be configured with resources (e.g., physical resource blocks, PRACH resources, PUSCH resources, preambles for (small) packet transmissions via RA procedures, and / or uplink configuration grant (UL-CG) configuration for (small) packet transmissions) on the supplemental uplink (SUL) carrier and / or normal uplink carrier (NUL). Also, as explained above, (small) packet transmissions may be performed via 2-step / 4-step RA procedures, and (pre-)configured resource transmissions (e.g., via UL-CG).

[0052] In some aspects of the disclosure, an indicator (e.g., a CellBarred bit) may act on the UE to determine whether the UE is permitted (or enabled) to initiate a (small) packet transmission procedure while the UE is in an RRC inactive / idle state.

[0053] In some implementations, the serving cell may transmit the CellBarred bit via broadcast (e.g., the cell may broadcast the CellBarred bit in a Master Information Block (MIB), which may be broadcast in a Physical Broadcast Channel (PBCH)). The CellBarred bit may be set to a value "barred" or "not forbidden". For example, if the UE receives the CellBarred bit, it may consider the serving cell (or a neighboring cell in the serving RAN) to be "barred". On the other hand, if the UE receives the CellBarred bit set to "not forbidden" while receiving system information, it may consider the serving cell to be "not forbidden". If the UE considers the serving cell to be "barred", the UE may not be allowed to select this cell (e.g., even for emergency calls) for at least a period of time (e.g., 300 seconds), and thus the UE may begin camping on another neighboring cell. In some implementations, the CellBarred bit may be set to a small packet transmission setting by the serving cell before the UE receives the CellBarred bit from the same serving cell. In some other embodiments, the small packet transmission configuration may be set by the serving cell before the UE receives the CellBarred bit from another serving cell.

[0054] In some embodiments, if a first cell is forbidden to the UE, the UE may not be permitted (or may be disabled) to perform (small) packet transmissions through an RA procedure with the first cell (or through one or more UL-CG configurations, which may be set by the first cell). If the CellBarred bit is set to "forbidden", the UE may consider the cell "forbidden" to itself. A cell in the serving RAN may broadcast the CellBarred bit through broadcast information (e.g., in a MIB). The UE may then reselect to another second cell and perform (small) packet transmissions through an RA procedure using the second cell.

[0055] In some embodiments, the MAC entity may release stored resources (with / without stored resource configuration) pre-configured for (small) packet transmissions through an RA procedure (if there is a configuration stored in the MAC entity) after the UE has set the CellBarred bit to "prohibited" during MIB reception.

[0056] In some other embodiments, the MAC entity may suspend stored physical resources (and / or stored resource configurations) that were preconfigured for (small) packet transmissions via an RA procedure. The suspended physical resources (and / or stored resource configurations) may be applicable again after the UE is enabled to transmit packets through the RA procedure (e.g., the cell may change the value of the “CellBarred” bit from “prohibited” to “not prohibited” to enable the UE to reactivate those “suspended” physical resources for small packet transmissions).

[0057] In some other implementations, the MAC entity may suspend stored physical resources (and / or stored resource configurations) preconfigured (by the first serving cell) for (small) packet transmissions via (at least) one UL-CG configuration. The suspended physical resources (and / or stored UL-CG resource configurations) may be applicable again after the UE is enabled to transmit packets with the first serving cell (e.g., the cell may later change the value of the "CellBarred" bit from "prohibited" to "not prohibited" to enable the UE to reactivate those "suspended" physical resources for small packet transmissions).

[0058] In some embodiments, a timer may be triggered (by the UE) to count to 0 while the MAC entity of the UE suspends the stored physical resources (and / or stored resource configurations) preconfigured for (small) packet transmission. The initial value of the timer may be predefined in a technical specification (e.g., 300 seconds) or may be set by the serving RAN via broadcasted system information or UE-specific RRC signaling. Before the execution timer expires (or counts to 0), the UE may be allowed to resume the suspended resource configurations (e.g., RA resource configurations and / or UL-CG resource configurations) while the UE does not discover a serving cell (e.g., CellBarred bit is set to "not prohibited"). However, in some additional embodiments, after the execution timer expires, the UE may release the suspended physical resources (and / or stored CG-SDT / RA-SDT resource configurations).

[0059] In some embodiments, the UE (or MAC entity) may consider the expiration of a time adjustment timer (TAT_inactive) for maintaining UL timing while the UE remains in an RRC inactive state after the UE receives a CellBarred bit set to "prohibited" during MIB reception. In some embodiments, the time adjustment timer (TAT_inactive) may be used while the UE is in an RRC_inactive state (i.e., an RRC inactive state). In some embodiments, the time adjustment timer (TAT_inactive) may be set in an RRC release (RRCRelease) message. For example, the time adjustment timer may be set in a suspend setting of the RRCRelease message.

[0060] In some embodiments, the TAT_inactive may be inactive after the UE receives a timing advance command in a random access response (RAR) message. The TAT_inactive may be released after the UE receives a timing advance command in a RAR message during an RA procedure. Another timing advance timer may be triggered at the same time.

[0061] In some embodiments, the UE may reset the MAC layer or MAC entity after the UE receives the cell prohibit bit set to "prohibited" during MIB reception.

[0062] In some other embodiments, the RRC entity may release the stored physical resources (and / or the stored resource configuration) pre-configured for (small) packet transmissions through an RA procedure (if there is a stored configuration in the RRC entity) after the UE receives the cell prohibit bit set to "prohibited" during MIB reception. In some embodiments, the RRC entity may be notified (or requested) by the MAC entity to release the stored physical resources (and / or the stored resource configuration).

[0063] In some other embodiments, the RRC entity may suspend stored physical resources (and / or stored resource configurations) that were preconfigured for (small) packet transmission via the RA procedure. In such cases, the suspended physical resources may be applicable again after the UE is enabled to transmit packets through the RA procedure (e.g., the same cell may change the "CellBarred" bit from "prohibited" to "not prohibited," thus enabling the UE to reactivate those "suspended" physical resources for small packet transmission). In some implementations, after receiving the CellBarred bit set to "not prohibited" from the serving cell, the UE may still need to run the UAC mechanism, and if the UE also passes the UAC mechanism, the UE is enabled to transmit packets through the RA procedure.

[0064] In some embodiments, on the UE side, the RRC entity may instruct the MAC entity to clear the stored physical resources preconfigured for (small) packet transmissions through the RA procedure. In some other embodiments, the RRC entity may release the stored physical resources preconfigured for (small) packet transmissions through the RA procedure. In some other embodiments, the RRC entity may instruct the MAC entity to suspend the stored physical resources (and / or the stored resource configurations) preconfigured for (small) packet transmissions through the RA procedure. In such a case, the suspended physical resources may be applicable again after the UE is enabled to transmit packets through the RA procedure (e.g., the cell may change the "CellBarred" bit from "prohibited" to "not prohibited", and thus the RRC entity may reactivate those "suspended" physical resources for small packet transmissions. The RRC entity may then reinstruct the MAC entity to apply these reactivated physical resources for packet transmissions through the RA procedure).

[0065] In some embodiments, the MAC entity may apply RA procedures for (small) packet transmissions without considering the cellBarred bit in the broadcast MIB. In some other embodiments, the MAC entity may apply SDT procedures for (small) packet transmissions via one or more UL-CG configurations without considering the CellBarred bit in the broadcast MIB.

[0066] In some embodiments, the UE may determine whether to initiate an RA-SDT procedure or a CG-SDT procedure while UL data arrives during an RRC inactive mode based on an indication indicated by the network. More specifically, the indication may or may not be a CellBarred bit. More specifically, the indication may be indicated by RRC signaling, a MAC control element (MAC CE), and / or a downlink control information (DCI).

[0067] However, in some implementations, the MAC entity may not be permitted to transmit RRC control signaling (e.g., an RRC Resume Request message) along with pending (user plane) packets in a triggered RA procedure if there is pending RRC control signaling in the MAC entity. Furthermore, the UE's MAC entity may remove (or refresh) pending RRC signaling if the UE considers the cell barred (e.g., by receiving a "cellBarred" bit set to "barred" in the MIB). In such a situation, C-Plane data transmission may be barred by the CellBarred bit, and U-Plane data transmission may not be barred by the CellBarred bit. In some other cases, neither U-Plane data nor C-Plane control signaling may be barred by the cellBarred bit.

[0068] In some aspects of the disclosure, the mechanism may also be applicable to UEs configured with a UL-CG configuration for (small) packet transmissions.

[0069] In some embodiments, the MAC entity may release stored resources (with / without stored resource configuration) pre-configured for (small) packet transmissions through the UL-CG procedure (if there is a configuration stored in the MAC entity) after the UE receives the CellBarred bit set to "forbidden" during MIB reception.

[0070] In some other embodiments, the MAC entity may suspend a stored UL-CG (and / or a stored UL-CG configuration) that was pre-configured for (small) packet transmissions. In such cases, the suspended UL-CG (and / or the stored UL-CG configuration) may be applicable again after the UE is enabled to transmit packets again (e.g., the cell may change the "CellBarred" bit from "prohibited" to "not prohibited" to enable the UE to reactivate their "suspended" physical resources for small packet transmissions).

[0071] In some embodiments, a timer may be triggered to count to 0 while the MAC entity suspends the stored UL-CG (and / or stored UL-CG configuration) pre-configured for (small) packet transmission. The initial value of the timer may be predefined in a technical specification (e.g., 300 seconds) or may be set by the serving RAN via broadcast system information or UE-specific RRC signaling. Before the execution timer expires (or counts to 0), the UE may resume the suspended resource configuration while the UE discovers that the serving cell is not barred to the UE (e.g., the cellBarred bit is set to "not barred"). After the execution timer expires, the UE may release the suspended UL-CG (and / or stored UL-CG configuration).

[0072] In some embodiments, the UE (or MAC entity) may clear all configured UL grants (or) pre-configured grants (e.g., for small packet transmissions) after the UE receives the cellBarred bit set to "prohibited" during MIB reception. In this disclosure, the terms "clear" and "release" do not differ in meaning and may be used interchangeably. For example, the UE clearing a configured UL grant may mean that the configured UL grant is released by the UE.

[0073] In some other embodiments, the RRC entity of the UE may release the stored UL-CG (and / or the stored UL-CG configuration) pre-configured for (small) packet transmission (if there is a stored configuration in the RRC entity) after the UE receives the cellBarred bit set to "forbidden" during MIB reception. In some embodiments, the RRC entity may be notified (or requested) by the MAC entity to release the stored UL-CG resources (and / or the stored UL-CG configuration).

[0074] In some other embodiments, the RRC entity of the UE may suspend the stored UL-CG (and / or the stored UL-CG configuration) that was preconfigured for (small) packet transmissions. In such cases, the suspended physical resources may be applicable again after the UE is allowed to transmit packets again (e.g., the cell may change the "CellBarred" bit from "prohibited" to "not prohibited" to allow the UE to reactivate those "suspended" physical resources for small packet transmissions).

[0075] In addition, the timer may be triggered to count to zero while the RRC entity suspends the stored UL-CG (and / or stored UL-CG configuration) pre-configured for (small) packet transmission. The initial value of the timer may be predefined in the technical specification (e.g., 300 seconds) or may be set by the serving RAN via broadcast system information or UE-specific RRC signaling. Before the execution timer expires (or counts to 0), while the UE discovers that the serving cell is not barred for the UE (e.g., the cellBarred bit is set to "not barred"), the UE may resume the suspended UL-CG (and / or stored UL-CG configuration). However, after the execution timer expires, the UE may finally release the suspended physical resources (and / or stored UL-CG configuration).

[0076] In some embodiments, the RRC entity may instruct the MAC entity to clear the stored UL-CG (and / or stored UL-CG configuration) preconfigured for (small) packet transmissions.

[0077] In some other embodiments, the UE's RRC entity may instruct the UE's MAC entity to suspend the preconfigured stored UL-CG (and / or stored UL-CG settings) for (small) packet transmissions. In such a case, the suspended UL-CG (and / or stored UL-CG settings) may be applicable again after the UE is enabled to transmit packets (e.g., the cell may change the "CellBarred" bit from "prohibited" to "not prohibited" and thus the RRC entity may reactivate those "suspended" physical resources for small packet transmissions). The RRC entity may then reinstruct the MAC entity to apply these reactivated physical resources for (small) packet transmissions via the configured UL-CG.

[0078] In addition, a timer may be triggered in the RRC entity to count to zero while the RRC entity suspends the stored UL-CG (and / or UL-CG configuration) pre-configured for (small) packet transmission. The initial value of the timer may be predefined in a technical specification (e.g., 300 seconds) or may be set by the serving RAN via broadcast system information or UE-specific RRC signaling. Before the running timer expires (or counts to zero), the RRC entity may instruct the MAC entity to resume the suspended UL-CG (and / or stored UL-CG configuration) while the UE discovers that the serving cell is not barred for the UE (e.g., the cellBarred bit is set to "not barred"). However, after the running timer expires, the RRC entity may instruct the MAC entity to release the suspended UL-CG (and / or stored UL-CG configuration).

[0079] In some implementations, after the UE transmits one (or more) UL packets through the (two-step / four-step) RA procedure or through a pre-configured UL-CG configuration, the UE may observe that the serving cell is barred while the UE is waiting for a HARQ response from the serving cell. In other words, if the SDT procedure has already been initiated by the UE, the cell may not be considered barred while the UE is transmitting UL packets. In some implementations, if the serving cell transmits one or more dynamic DL assignments / UL grants, also referred to as subsequent packet transmissions, to the UE during the SDT procedure, the ongoing SDT procedure may be extended by the serving cell. In this state, the subsequent packet transmissions may be considered as part of the SDT, and thus the UE may not detect the "CellBarred" bit of the serving cell during the subsequent packet transmission (or the UE may ignore the "CellBarred" bit of the serving cell). In some other implementations, the UE may not perform the UAC mechanism for subsequent packet transmissions after the SDT procedure has already gone through the UAC mechanism.

[0080] Thus, in some embodiments, the "CellBarred" bit may not affect the feedback mechanism, which means that even if the UE detects that the "CellBarred" bit is "prohibited" during a (small) packet transmission, the UE may still be able to receive a Hybrid Automatic Repeat Request (HARQ ACK / NACK message or a discontinuous transmission (DTX) state (which means no response is received from the serving cell). The serving cell may generate and send a HARQ response message to the UE after the CellBarred bit is prohibited. Furthermore, the ongoing (small) packet transmission may continue until the UL packet transmission is terminated (e.g., when the UE receives a HARQ ACK message, when the UE reaches a maximum retransmission for HARQ retransmission, or when the UE receives an RRC message from its serving cell to terminate the ongoing SDT procedure).

[0081] In some implementations, when the UE is performing small packet transmission (e.g., when the UE is waiting for a HARQ response), it may ignore the CellBarred bit broadcast by the serving cell. Although the UE may receive the cellBarred bit, the UE may ignore the cellBarred bit. For example, the UE may ignore the CellBarred until the ongoing UL packet transmission is terminated (e.g., when the UE receives one HARQ ACK message, when the UE reaches the maximum retransmissions for HARQ retransmissions, or when the UE receives an RRC message from its serving cell to terminate an ongoing SDT procedure).

[0082] In some other embodiments, the UE may stop monitoring for (HARQ) responses from the serving cell after it detects that the "CellBarred" bit is "prohibited". In addition, the UE may flush the soft buffer after it detects that the "CellBarred" bit is "prohibited". For an RA procedure (start for small packet transmission), an ongoing RA procedure may also be stopped. In such a case, in some embodiments, the UE may not count this event (UL packer transmission is blocked by the serving cell) as a failed HARQ retransmission. In some other embodiments, the UE may count this event (UL packet transmission is prohibited by the serving cell) as a failed HARQ retransmission.

[0083] In some implementations, an ongoing (2-step / 4-step) RA procedure (triggered for small packet transmission) (i.e., RA-SDT procedure) may be aborted after the UE detects that the CellBarred bit is "barred" from the serving cell. In some embodiments, an ongoing RA-SDT procedure may be stopped regardless of whether the UE has successfully transmitted any preambles / (small) packets or whether the UE is waiting for a HARQ response message. In some other embodiments, an ongoing small packet transmission performed via one or more stored UL-CG configurations (i.e., CG-SDT procedure) may be aborted after the UE detects that the CellBarred bit is "barred" from the serving cell. In some embodiments, an ongoing CG-SDT procedure may be stopped regardless of whether the UE has successfully transmitted any preambles / (small) packets or whether the UE is waiting for a HARQ response message.

[0084] In some embodiments, even when the UE is disconnected from the source serving cell and connected to the target serving cell, the pre-configured physical resources (and / or stored resource configurations) for (small) packet transmission via an RA procedure from the source serving cell may be maintained (i.e., not released).

[0085] In some embodiments, the UE may maintain (i.e., not clear) the stored UL-CG (and / or the stored UL-CG configuration) pre-configured for (small) packet transmissions from the source cell even when the UE disconnects from the source cell and connects to the target serving cell.

[0086] In some embodiments, the UE may maintain (i.e., not flush) a HARQ buffer associated with one SDT procedure even if the UE disconnects from the source serving cell and connects to a target serving cell, and thus the SDT procedure (associated with the source serving cell) may be interrupted.

[0087] In some embodiments, an effective area may be configured together with the physical resource configuration or UL-CG configuration. For example, the UE may keep the stored physical resource configuration / UL-CG configuration (including TBs pending in the buffer in some implementations) only while the target serving cell also belongs to the effective area of ​​the stored physical resource configuration (e.g., random access resources) / UL-CG configuration. Otherwise (e.g., the selected target cell may not be part of the defined effective area), the UE may delete (or release) the stored physical resource configuration or UL-CG configuration after reselecting to the target serving cell.

[0088] The effective area information may be configured by at least one cell identity (e.g., a cell identity or physical cell identity (PCI) that may be broadcast by the respective cell in the broadcast system information), a system information area code / system information area ID, a tracking area code (TAC) or a RAN notification area code (RNAC). In some implementations (e.g., in a RAN sharing scenario), the effective area may be further associated with one network identity (e.g., a first PLMN identity configured in a network identity list broadcast by the serving cell via the broadcast system information).

[0089] In some implementations, the source serving cell and the target serving cell may operate on the same frequency carrier (DL / UL). In some other implementations, the source serving cell and the target serving cell may operate on different frequency carriers (DL / UL).

[0090] During the cell (re)selection procedure, the UE may give higher priority to cells within a given coverage area (compared to cells not within the given coverage area). The coverage area configuration may be removed / released after the UE moves to RRC idle state or to another RAT (e.g., E-UTRA).

[0091] Furthermore, pending (multiplexed) TBs in layer 1 (e.g., physical layer) / layer 2 (e.g., MAC layer) may be removed while the UE detects that the "CellBarred" bit is "forbidden" during (small) packet transmission. In some other embodiments, pending TBs in layer 2 (e.g., RLC layer, PDCP layer, SDAP layer) may be suspended or released while the UE detects that the "CellBarred" bit is "forbidden" before the UE is allowed / enabled to initiate one SDT procedure (e.g., RA-SDT procedure or CG-SDT procedure). The RA-SDT procedure may refer to an SDT procedure in which the UE performs SDT over RA procedures / resources. The CG-SDT procedure may refer to an SDT procedure in which the UE performs SDT over UL-CG resources.

[0092] It should be noted that some of the mechanisms described above or below are described for the "CellBarred" bit in the MIB. In some implementations, the described mechanisms are applicable to other cell barring settings delivered by the serving cell through broadcast system information. In some other implementations, the described mechanisms are applicable to the condition that the serving cell does not broadcast any Tacking Area Code (TAC). In such a case, the UE may also consider such a cell as barred. In some other implementations, the described mechanisms may be applied when a condition is met for the UE to perform a cell reselection procedure to another cell and / or when the UE initiates a cell reselection procedure. In one embodiment, when a condition is met for the UE to perform a cell reselection procedure to another cell and / or when the UE initiates a cell reselection procedure, the stored resources (with / without stored resource settings) preconfigured for small packet transmission (if there is a stored setting in the MAC entity) may be released or cleared. In another embodiment, the MAC entity may suspend stored physical resources (and / or stored resource configurations) pre-configured for (small) packet transmissions through an RA procedure (or via a configured UL-CG configuration) when the condition(s) for performing a cell reselection procedure to another cell is met and / or when the UE initiates a cell reselection procedure.

[0093] In some embodiments, the timers described in this disclosure may be reset (or recounted) when the UE receives a new SDT configuration from the serving cell (e.g., through broadcast system information or through UE-specific control signaling such as an RRCRelease message).

[0094] In some aspects of the present disclosure, the UE may receive an RRCReject message while multiplexing an RRC Resume Request (RRCResumeRequest) (or RRCResumeRequest1) message with U-Plane data.

[0095] For example, the RRCResumeRequest (e.g., RRCResumeRequest for RAN Notification Area Update procedure) with or without multiplexing information may be conveyed via the RA procedure. Then, after receiving the RRCReject message during the RA procedure, the UE may release the active data radio bearers (DRBs) (e.g., active DRBs for packet transmission while the UE remains in the RRC inactive state) or active signaling radio bearers (SRBs) (e.g., active SRBs such as SRB0 / SRB1 / SRB2 for packet transmission while the UE remains in the RRC inactive state). In some embodiments, the active DRBs / SRBs may be suspended after the UE receives the RRCReject message. Pending packets (e.g., pending TBs in the buffer) may be deleted / released after the UE receives the RRCReject message.

[0096] In some implementations, if the UE receives an RRCReject message from the (same) serving cell, the pre-configured UL-CG configuration may also be released. In some implementations, if the UE receives an RRCReject message from the (same) serving cell, the pre-configured UL-CG configuration may be suspended. In some other implementations, the pre-configured UL-CG configuration may still be active while the UE receives an RRCReject message from the (same) serving cell. In some embodiments, if the UE receives an RRCReject message, the higher layer of the UE (e.g., the RRC entity) may instruct the lower layer of the UE (e.g., the MAC entity) to clear the configured grant and / or release the UL-CG configuration when the UE receives an RRCReject message.

[0097] In some embodiments, when the UE receives an RRCReject message, the UE (e.g., the MAC entity of the UE) may consider a time adjustment timer to expire. In some embodiments, the UE (or the MAC entity of the UE) may consider a time adjustment timer (e.g., one time adjustment timer (TAT_inactive)) to maintain UL timing while the UE remains in an RRC inactive state to expire after the UE receives a cellBarred bit set to "prohibited" during MIB reception. In some embodiments, the time adjustment timer (TAT_inactive) may be used while the UE is in an RRC inactive state. In some embodiments, the time adjustment timer (TAT_inactive) may be set during (the suspend setting of) an RRCRelease message. In some implementations, each time the UE receives one timing advance command (e.g., a timing advance command MAC CE or a timing advance command in an RAR message during an RA procedure) from its serving cell, it may reset TAT_inactive to its initial value and then count TAT_inactive to 0. The UE may then consider the CG-SDT procedure to have failed or the CG-SDT configuration to be invalid if TAT_inactive expires. In some other embodiments, TAT_inactive may not be active after the UE receives a timing advance command in a RAR message. Thus, TAT_inactive may be released after the UE receives a timing advance command in a RAR message during the RA procedure. Then, another timing advance timer may be triggered at the same time.

[0098] In some embodiments, if the UE receives an RRCReject message, it may reset the MAC entity / layer. The serving cell may be considered as either UL-CG configuration is released (thus disabling the UE from (small) packet transmission via RA procedure) or suspended by sending an RRCReject message to the UE. Furthermore, pending packets (e.g., packets pending in the MAC buffer) may also be released (or removed) from the (HARQ / MAC) buffer. The MAC buffer (or soft buffer pending for HARQ processing) may be flushed after receiving an RRCReject message from the serving cell (e.g., a serving cell that allows the UE to perform (small) packet transmission while the UE remains in an RRC inactive state).

[0099] In some other embodiments, the RRCResumeRequest with / without multiplexed data (e.g., RRCResumeRequest for RNAU procedure) may be delivered first over preconfigured UL-CG resources. Then, after receiving an RRCReject message (by receiving a response message from the serving cell after uplink packet transmission over the preconfigured UL-CG), the UE may release active data radio bearers (DRBs, e.g., active DRBs (if any) for packet transmission while the UE remains in the RRC inactive state) and / or active SRBs.

[0100] In some embodiments, if the DRB is released after the UE receives an RRCReject message from the serving cell, the signaling radio bearer (eg, SRB1) may be applied for uplink (small) packet transmission.

[0101] In some embodiments, SRB1 may be retained (and suspended) after the UE receives the RRCReject message. In contrast, the active / resume DRBs may be released. In such a situation, the UE may recreate the TB to be transmitted, and then the UE may attempt to transmit the pending TB through SRB1 instead. In some implementations, this mechanism may be considered as one switching mechanism for the serving cell to instruct the UE to switch from the UP solution to the CP solution. Also, note that in some embodiments, one explicit indicator may be given in the RRCReject message to instruct the UE to switch the (small) packet transmission approach. In some other embodiments, it is an implicit switching approach, and thus the UE may implicitly switch the (small) packet transmission approach from the UP solution to the CP solution after receiving the RRCReject message.

[0102] In some embodiments, the preconfigured UL-CG configuration may also be released if the UE receives an RRCReject message from the (same) serving cell. In some embodiments, the preconfigured UL-CG configuration may be suspended if the UE receives an RRCReject message from the (same) serving cell. In some other embodiments, the preconfigured UL-CG configuration may be active while the UE receives an RRCReject message from the (same) serving cell.

[0103] In some embodiments, an explicit indicator may be provided in the RRCReject message to instruct the UE to release the stored UL-CG configuration (and / or the stored physical resource configuration for packet transmission via the (2-step / 4-step) RA procedure). In some embodiments, the UE may release the stored UL-CG configuration in an implicit manner where no indicator is provided in the RRCReject message.

[0104] In some embodiments, after receiving the RRCReject message, the UE may only remove the stored (physical resources for RA procedure / UL-CG) configuration that the UE obtains through UE-specific control signaling (e.g., RRCRelease message or RRCReconfiguration message). In other words, an (RRC_Inactive) UE can perform packet transmission through a normal RA procedure or UL-CG configuration after receiving the RRCReject message if the corresponding configuration is provided by the serving cell through cell-specific control signaling (e.g., Broadcast System Information or SI on Demand procedure).

[0105] The serving cell may also consider the UL-CG configuration to be released (and therefore the UE is disabled from (small) packet transmissions via the RA procedure and / or via the grants configured) by sending an RRCReject message to the UE.

[0106] Additionally, pending packets (e.g., packets pending in a MAC buffer) may also be released (or deleted) from the buffer. The MAC buffer (or soft buffers pending for HARQ processing) may be flushed after receiving an RRCReject message from a serving cell (e.g., a serving cell that allows the UE to perform (small) packet transmissions while the UE remains in an RRC inactive state).

[0107] In some embodiments, the mechanisms described above and below may be applicable only to UEs that are enabled to perform a (2-step / 4-step) RA procedure or a (pre-configured) UL-CG configuration (when the UE is in an RRC inactive state).

[0108] In some embodiments, the mechanisms described above and below may be applicable only to serving cells that allow the UE to transmit packets through an RA procedure or that the UE configures a UL-CG configuration for transmitting packets (when the UE is in an RRC inactive state). In addition, the UE may omit to perform the described mechanisms and fall back to an RRC inactive UE that is disabled from packet transmission in the RRC inactive state after the UE reselects (or is redirected) another serving cell. In some other embodiments, the UE may omit to perform the described mechanisms and fall back to an RRC idle UE after the UE reselects (or is redirected) another serving cell.

[0109] In some embodiments, the mechanisms described above and below may cover an RRC resumption procedure in which the UE sends an RRC Resume Request (RRCResumeRequestI) message or an RRC Resume Request 1 (RRCResumeRequest1) message.

[0110] In some embodiments, for a transmitted UL packet (multiplexed with an RRCReject message), the UE may not count this event as a UL packet transmission failure event, while in some other embodiments, the UE may count this event as a UL packet transmission failure event.

[0111] In some embodiments, for a transmitted UL packet (where the UE receives an RRCReject message in response to a transmitted UL packet), the UE may not count this event as a UL HARQ packet (re)transmission failure event, while in some other embodiments the UE may count this event as a UL HARQ (re)transmission failure event.

[0112] As described above, the UE may transmit a RRCResumeRequest (or RRCResumeRequest1) message by applying resources reserved for (small) packet transmission. However, in conventional TS, the UE may still need to perform UAC while the RA procedure is initiated for the RRC resumption procedure. In consideration of this, some embodiments provide a mechanism for the UE to determine whether to perform a UAC procedure for small packet transmission while the small packet is being transmitted through the RA procedure. Some other embodiments provide a mechanism for the UE to determine whether to perform a UAC procedure for small packet transmission while RRC signaling (e.g., RRCResumeRequest message) is being transmitted jointly. Some other embodiments provide a mechanism for the UE to determine which access category may be applied while the UE transmits an RNA update request message and the RNA update request message is multiplexed with the (small) packet. Some other embodiments provide a mechanism for determining whether the UE is still permitted to perform small packet transmissions by initiating another RA procedure when the UE is prohibited from an RNAU procedure (e.g., due to a UAC decision while the UE is triggered to initiate an RNA Update (RNAU) procedure).

[0113] During the RRC resume procedure, the UAC mechanism may be executed on the RRC layer, and the MAC entity may initiate the RA procedure based on the command of the RRC layer (e.g., while passing the UAC). Furthermore, the MAC entity may initiate the RA procedure by itself (e.g., for small packet transmission), and the RRC entity may or may not be involved (so the UAC may not be executed). The UE may be configured to execute the UAC mechanism while the UE is triggered to transmit a UL packet through the RA procedure. In some embodiments, the UE may be configured with one specific access category (and / or one specific access identity) for small packet transmission. It should be noted that in some embodiments, both the RA-SDT procedure and the CG-SDT procedure may share the same access category. However, in some embodiments, the RA-SDT procedure and the CG-SDT procedure may be configured with different access categories. In some embodiments, the access category of the RA-SDT / CG-SDT procedure may be predefined in a technical specification, pre-installed in a memory module on the UE side, and may be configured by the serving RAN via broadcast system information or through one or more UE-specific DL-RRC signaling.

[0114] In some implementations, if the UE is not configured with any particular access identity / access category from the serving cell or pre-configuration, the UE may automatically (e.g., while an access attempt is initiated for a small packet transmission) use one default access identity (e.g., access identity number is set to "0") and / or default access category (e.g., access category is set to "0"). For small packet transmission, it may be that the UE may use at least one of the operator-defined access categories.

[0115] FIG. 1 is a schematic diagram illustrating a process for an access control mechanism while a UE 10 attempts to initiate an SDT procedure with a serving RAN 12, according to an embodiment of the present disclosure.

[0116] In action 102, the UE 10 may receive an SDT configuration from a serving cell that is part of the UE 10's serving RAN 12 when the UE remains in the RRC connected state. The SDT configuration may be included in UE-specific RRC signaling, such as an RRC Reconfiguration message or an RRCRelease message (e.g., an RRCRelease message with an IE suspend configuration used to instruct the UE to transition to an RRC inactive state). After receiving the SDT configuration, the UE 10 may transition to an RRC inactive state according to the received SDT configuration. In some embodiments, the SDT configuration may include at least one of an RA resource configuration and a (type 1) UL-CG configuration. In some embodiments, the SDT configuration may further indicate the radio bearers (or RLC bearers / logical channels) that are enabled / configured for small data transmission (while the UE remains in the RRC inactive state) and / or the logical channels associated with these radio bearers / RLC bearers / logical channels. In some additional embodiments, the SDT configuration may further include Layer 2 (e.g., PDCP / RLC / MAC layer) / Layer 1 (e.g., PHY layer) settings / parameters of these (radio / RLC) bearers / logical channels for small data transmission.

[0117] RA resource configuration(s) (e.g., physical resource block (PRB) locations for the UE to transmit preambles and / or multiplexed data and preamble sets that the UE may select to transmit to the serving cell during the RA procedure). In some other embodiments, the RA resource configuration may include radio resource configuration for the UE 10 to initiate a two-step RA procedure and / or radio resource configuration for the UE 10 to initiate a four-step RA procedure. In some embodiments, the RA resource configuration for the SDT procedure is an RA-SDT configuration, and the SDT procedure performed via the two-step / four-step RA procedure is an RA-SDT procedure. In some implementations, the UE 10 may receive the RA-SDT configuration of its serving cell via broadcast system information (e.g., via SIB1 or a SIB specific to the SDT configuration). Also, the UE 10 may receive the SDT-specific SIB via a dedicated SIB request procedure or a SI (System Information) on Demand procedure for an SDT-specific SIB that contains the SDT configuration of one cell. In some additional embodiments, the RA resource configuration may include radio resource configuration designated for a (2-step / 4-step) contention-based RA (CBRA) procedure and / or a contention-free RA (CFRA) procedure.

[0118] Meanwhile, a (type 1) UL-CG configuration (e.g., a PRB position for a UE to transmit one UL control signaling with data multiplexed via the configured type 1 UL-CG configuration). In some embodiments, the PRB for the UL-CG configuration may appear periodically in the time domain, so that the UE may utilize the UL-CG configuration for SDT when there is a pending packet available. In some embodiments, a type 1 UL-CG configuration for an SDT procedure is a CG-SDT configuration, and an SDT procedure performed via a type 1 UL-CG configuration is a CG-SDT procedure.

[0119] In some embodiments, the SDT configuration may further indicate one or more logical channels available / allowed / enabled for SDT. Thus, when one or more packets arrive at layer 2 (e.g., a MAC entity), the MAC entity may identify the logical channel with which the arriving packets are associated. The UE 10 may decide to initiate an SDT procedure if there are pending packets in one or more logical channels enabled / configured for SDT (during the UE's RRC inactive state). In contrast, the UE 10 may initiate one RRC resumption procedure with its serving cell of the serving RAN 12 if there are pending packets in one or more logical channels not enabled for SDT during the UE's RRC inactive state. Thus, in action 104, the UE 10 may perform an access control (mechanism) for the SDT procedure after the UE 10 observes one or more pending packets in at least one logical channel enabled for the SDT procedure. It should also be noted that in some embodiments, (part of) the proposed access control mechanism for the SDT procedure may be performed before there are pending packets associated with the logical channels configured / enabled for the SDT procedure. For example, if the UE is forced to (re)select another serving cell (e.g., cell #2) due to the original serving cell (e.g., cell #1 which configures the UE with an SDT setting) being considered forbidden, then (part of) the stored SDT setting may become invalid after the cell reselection procedure and the UE should not perform the SDT procedure with cell #2 which has (part of) the invalid SDT setting.

[0120] In action 106, the UE 10 may perform SDT initiation by initiating an SDT procedure with a serving cell of the serving RAN 12 if the UE 10 passed access control for the SDT procedure in action 104. The UE 10 may (temporarily) not be able to initiate any SDT procedure (with that serving cell) if the UE 10 does not pass access control.

[0121] The UE 10 may perform the action 106 by various approaches. For example, the UE 10 may initiate the CG-SDT procedure by accessing (at least) one UL-CG physical resource for transmitting (at least) an UL packet (with / without multiplexing with an RRC Resume Request (RRCResumeRequest) message), which includes a UE-ID (e.g., I-RNTI) for a serving cell of the serving RAN 12 to identify the source of the UL packet. In another embodiment, the UE 10 may initiate the RA-SDT procedure by accessing (at least) one RA physical resource for transmitting an UL packet with multiplexing with an RRCResumeRequest message, which includes a UE-ID (e.g., I-RNTI) for a serving cell of the serving RAN 12 to identify the source of the UL packet. In some embodiments, the RA-SDT procedure may be performed via a four-step RA procedure (e.g., the UE may send multiplexed RRC Resume Request messages in MSG3 in an UL packet w / wo during a four-step RA procedure), and thus action 106 may be performed via an MSG3 transmission from the UE 10 to a serving cell of the serving RAN 12. In some other embodiments, the RA-SDT procedure may be performed via a two-step RA procedure (e.g., the UE may send multiplexed RRC Resume Request messages in MSGA in an UL packet w / wo during a two-step RA procedure), and thus action 106 may be performed via an MSGA transmission from the UE to a serving cell of the serving RAN 12.

[0122] After receiving the UL packet from the UE 10 (e.g., sent by the UE 10 in action 106), the serving cell of the serving RAN 12 may respond with a layer 1 ACK / NACK message (e.g., a HARQ ACK / NACK message) to the UE 10 to inform the UE 10 whether the UL packet was successfully received by the serving cell of the serving RAN 12. Then, in some embodiments, the serving cell of the serving RAN 12 may further configure a dynamic DL assignment / UL grant, which may be transmitted to the UE 10 via a downlink control information (DCI) in a physical downlink control channel (PDCCH) to enhance the ongoing SDT procedure. Thus, during a subsequent packet exchange in action 108, the UE 10 may receive a DL packet based on the received dynamic downlink assignment (via at least one DCI), and the UE 10 may then send a HARQ ACK / NACK message back to the serving cell of the serving RAN 12 (also based on the received DCI associated with the DL packet). Additionally, also during the subsequent packet exchange at action 108, the UE 10 may transmit a UL packet based on the received dynamic UL grant (via at least one DCI), and then the UE 10 may wait for the serving cell of the serving RAN 12 to return a HARQ ACK / NACK message for the UL packet (also based on the received DCI associated with the UL packet). During the SDT procedure (and subsequent packet exchange), the UE 10 and the serving cell of the serving RAN 12 may further exchange Layer 2 ACK / NACK messages (e.g., ARQ ACK / NACK messages) for the DL / UL packet exchange.

[0123] In action 110, the serving cell of the serving RAN 12 may send (at least) one SDT Termination message to the UE 10 to terminate the ongoing SDT procedure (which may or may not include a subsequent packet exchange in action 108). In some embodiments, the serving cell of the serving RAN 12 may send an RRC Release message (e.g., an RRC Release message with suspend configuration) to instruct the UE 10 to terminate the ongoing SDT procedure and remain in an RRC Inactive state. In some embodiments, the serving cell of the serving RAN 12 may send an RRC Release message (e.g., an RRC Release message without suspend configuration) to instruct the UE 10 to terminate the ongoing SDT procedure and transition to an RRC Idle state. In some other embodiments, the serving cell of the serving RAN 12 may send an RRC Resume message (or an RRC Re-establishment message) to instruct the UE 10 to terminate the ongoing SDT procedure and transition to an RRC Connected state. In some other embodiments, the serving cell of the serving RAN 12 may send an RRC SETUP message to instruct the UE 10 to terminate the ongoing SDT procedure, transition to an RRC IDLE state, and reconnect with the serving cell of the serving RAN 12.

[0124] The UE 10 may reselect its serving cell (e.g., a serving cell of the serving RAN 12) in one or more actions shown in FIG. 1. In some implementations, the UE may receive an SDT configuration using serving cell #1, and then the UE may move and reselect to another cell #2 as the UE's serving cell. In this state, the UE 10 may perform an access control mechanism using the (serving) cell #2 in action 104. In some implementations, the UE 10 may reselect during the SDT procedure (or during subsequent packet exchanges) to another cell (e.g., cell #3). In some implementations, if the UE is in an SDT procedure and cell reselection is performed, the UE may suspend the ongoing SDT procedure (and subsequent packet exchanges) and remain in an RRC inactive state (and the stored SDT configuration may or may not be maintained by the UE 10 after the UE 10 reselects cell #3). In some other embodiments, the UE 10 may suspend ongoing SDT procedures (and subsequent packet exchanges) and transition to the RRC idle state. The stored SDT configuration may not be retained by the UE after the UE 10 transitions to the RRC idle state.

[0125] FIG. 2 illustrates an example of an RA-SDT procedure according to an embodiment of the present disclosure.

[0126] After receiving the RRCRelease message from its serving cell, the UE may remain in the RRC inactive state with the stored SDT configuration. If the UE in the RRC inactive state has uplink data available for transmission, the UE passes the access control for the SDT procedure. The UE may initiate the RA-SDT procedure for the transmission of UL data (e.g., if the CG-SDT configuration is not considered valid). The UE may select a 4-step RA type or a 2-step RA type for the RA-SDT procedure. Furthermore, the preamble / PRACH resources for the RA-based SDT procedure (e.g., RA preamble / PRACH resources configured for SDT) and the normal RA procedure (e.g., RA preamble not configured for SDT) may be different. As shown in action 202 of FIG. 2, the UE 20 may transmit (select) the preamble / PRACH resources configured for the RA-SDT procedure.

[0127] After transmitting the (RA) preamble / PRACH resource to the RAN 22 in action 202, the UE 20 may wait for a response (e.g., an RAR message) from a serving cell of the RAN 22 during the RA-SDT procedure (contention-based) four-step RA procedure in action 204. The (MSG2) RAR message received in action 204 may further include a UL dynamic grant for the UE 20 to transmit the next MSG3.

[0128] In action 206, the UE 20 may transmit an RRC message (e.g., a Common Control CHannel (CCCH) message), MAC CE(s), and / or UL data via MSG3 (if a four-step RA type is selected for the RA-SDT procedure) or MSGA (if a two-step RA type is selected for the RA-SDT procedure). The RRC message may be an RRCResumeRequest message. In addition to the RRC message, MAC CE (e.g., a buffer status report) and UL data (e.g., data related to DRB / SRB for SDT) may also be included in MSG3 / MSGA. In some embodiments, the two-step RA procedure (for SDT) may be performed by merging action 202 and action 206 in a PRACH resource pre-configured for the two-step RA procedure (and in such a case, action 204 may be omitted during the two-step RA procedure).

[0129] Once MSG3 / MSGA is sent, in action 208, the UE 20 may monitor (e.g., temporary C-RNTI) / C-RNTI / RA-RNTI / MSGB-RNTI for MSG4 / MSGB, in which the contention resolution ID is carried. The RAN 22 may also send an RRC message in MSG4 (if a 4-step RA type is selected in the RA-SDT procedure) / MSGB (if a 2-step RA type is selected in the RA-SDT procedure). The RRC message may be an RRCRelease message (with a suspendConfig IE) or an RRCResume message. The UE 20 may remain in an RRC inactive state if it receives an RRCRelease message (with a suspendConfig IE), and thus may terminate the ongoing SDT procedure. In some embodiments, the RA-SDT procedure may be considered to have completed successfully after the UE 20 successfully receives MG4 / MSB (e.g., as an ACK message from the serving cell of RAN 22 indicating that the UL data in MSG3 / MSGA was successfully received by the (serving) RAN 22).

[0130] In some embodiments, the RA-SDT procedure may be further extended (or a new subsequent packet exchange procedure may be initiated after the RA-SDT procedure is terminated, as shown in action 210). For example, in action 210, the UE 20 may monitor a specific RNTI (e.g., C-RNTI) on a specific search space for a subsequent packet exchange. In some implementations, a serving cell of the RAN 22 may transmit one or more UL dynamic grants in action 208 / action 210 for a subsequent packet exchange. The subsequent packet exchange may be a transmission of multiple UL and / or DL ​​data packets without transitioning to an RRC connected state (e.g., the UE 20 is still in an RRC inactive state) as part of the SDT procedure. The UE 20 may monitor the PDCCH via the specific RNTI (e.g., C-RNTI) to receive dynamic scheduling for new transmissions and / or corresponding packet retransmissions (e.g., HARQ retransmissions and / or ARQ retransmissions) in the UL and / or DL.

[0131] At action 212, the (serving) RAN 22 may send an RRC Release (with suspendconfig) message to the UE 20 to keep the UE 20 in the RRC inactive state. When the RRCRelease message (with suspendConfig IE) is received, the UE 20 may terminate the RA-SDT procedure based on the RRCRelease message and / or stop monitoring the C-RNTI and remain in the RRC inactive state.

[0132] FIG. 3 illustrates an example of a CG-SDT procedure according to an embodiment of the present disclosure.

[0133] The serving RAN (e.g., RAN 32) may decide to transition the UE 30 to an RRC inactive state by sending a RRCRelease message (including a suspendconfig IE) to the UE 30. The RRCRelease message may include a UL-CG configuration for configuring UL-CG resources in the UE 30. The (UL-)CG configuration may include at least one of a CG periodicity, a TB size, a number for implicit release of CG resources, a CG timer, a retransmission timer, one or more HARQ processes (and HARQ process IDs) reserved / configured for CG during the SDT, a downlink RSRP threshold for SSB selection, and an association between SSBs and CG resources, TA-related parameters (e.g., cg-SDT-TimeAlignmentTimer), etc.

[0134] In action 302, the UE 30 may perform small data transmission via a CG-SDT procedure based on the configured CG resources. Then, in action 304, the UE 30 may monitor a response message from the serving RAN 32 (e.g., a HARQ ACK / NACK message for the UL packet transmitted in action 302). In some embodiments, the serving cell of the RAN 32 may also send a RRCRelease message (with a suspend configuration (or suspend configuration IE)) to the UE 30. After receiving the RRCRelease message, the UE 30 may terminate the CG-SDT procedure.

[0135] In some embodiments, the subsequent packet exchange may be performed (at action 306) as part of the CG-SDT procedure (e.g., the UE is still in an RRC inactive state). The UE 30 may (at least) monitor the PDCCH via a specific RNTI (e.g., C-RNTI, CS-RNTI, and / or a new RNTI for SDT) over a search space (e.g., configured as part of the SDT configuration) to receive dynamic scheduling for UL grant(s) and / or DL ​​assignments and / or corresponding retransmissions (e.g., HARQ retransmissions and / or ARQ retransmissions). The UE 30 may (at least) monitor the PDCCH via a unique RNTI to receive dynamic scheduling for retransmissions of packets transmitted via the stored UL-CG configuration. The UE 30 may also perform subsequent data transmissions via CG resources according to the CG configuration (e.g., configured in action 102 of FIG. 1). At action 308, the serving RAN 32 may send a RRCRelease message (with suspendconfig IE) to keep the UE 30 in an RRC inactive state. When the RRCRelease message (with suspendConfig IE) is received, the UE 30 may terminate the CG-SDT procedure in response to receiving the RRCRelease message.

[0136] 4 illustrates a flow chart of a method 400 of access control for SDT procedure according to an embodiment of the present disclosure. At action 402, the UE remains in an RRC inactive state using a stored configuration for SDT (which the UE receives from its serving cell via an RRCRelease message reception).

[0137] The UE may then move within the coverage of a serving radio access network (consisting of one or more cells, each configured and supported by a base station such as a NR, gNB or E-UTRA eNB). Then, while the UE is moving within the radio coverage, the UE may perform a cell reselection procedure to select one serving cell to camp on. Also, the UE may continue to receive system information (e.g., MIB, SIB1, SIB2) broadcasted by the same serving cell to monitor the working status of the serving cell.

[0138] At action 404, the UE may check whether the "CellBarred" bit broadcast by the serving cell (even though the UE may already have stored the SDT configuration sent by the same serving cell) is "forbidden". In some additional implementations, the UE may also check whether the "CellBarred" bits broadcast by its neighboring cells are "forbidden", and then the UE will not reselect a cell whose CellBarred bit is "forbidden" during a cell (re)selection procedure.

[0139] In action 406, the UE may reselect another cell as its serving cell if the cellBarred bit of the serving cell indicates "forbidden." In contrast, in action 408, the UE may stay on the (same) serving cell if the cellBarred bit of the serving cell indicates "not forbidden."

[0140] In some embodiments, the UE may move from the original serving cell (e.g., cell #1) to the newly selected cell (e.g., cell #2) after a cell reselection procedure due to the cellBarred bit of cell #1="barred". The UE may have stored the SDT configuration set by cell #1. In this state, even if the UE receives the CellBarred bit of cell #1, when the UE camps on cell #2, the UE may still hold / suspend / retain the stored SDT configuration (e.g., CG-SDT configuration including UL-CG configuration for SDT set by cell #1) even if at least a part of the stored CG-SDT configuration becomes invalid. Thus, if the UE returns to camp on cell #1 again after the UE observes CellBarred of cell #1="not forbidden" in the next cell reselection procedure, the UE may still have a chance to perform the SDT procedure on cell #1, thereby reducing signaling overhead. In some other embodiments, the UE may release / clear / delete (at least a portion of) the stored SDT configuration (e.g., CG-SDT configuration including UL-CG configuration for SDT) set by cell #1 when / after the UE reselects to another cell due to cell #1's cellBarred bit being set to "forbidden".

[0141] In block 410, the UE may determine whether a UL packet arrives on a logical channel enabled for SDT, for example, by monitoring UL packet arrivals from higher layers (e.g., application layer, NAS layer) on the UE side. In some embodiments, the arriving UL packet may be associated with one or more radio bearers (or RLC bearers) configured by a stored SDT configuration for the SDT procedure.

[0142] In action 412, the UE may determine whether the total amount of reserved data for the logical channels (enabled for the SDT procedure) is less than or equal to a given data amount threshold for SDT (e.g., included in the SDT configuration). If the total amount of reserved data for the logical channels is less than or equal to the data amount threshold for SDT, the UE may determine that the SDT procedure may be initiated.

[0143] In action 414, after the UE determines that the SDT procedure may be initiated, the UE may check whether the UAC (mechanism) passes by executing a UAC procedure (or "UAC mechanism") based on the access category and access class determined by the UE for the SDT procedure. In some embodiments, the access class / access category (e.g., the access class / access category for the SDT procedure) may be predefined in a 3GPP technical specification, and the access class / access category may be preinstalled in the memory or other storage module of the UE. After executing the UAC mechanism, in action 418, if the UE passes the UAC mechanism, the UE may initiate the SDT procedure (e.g., a CG-SDT procedure or a RA-SDT procedure). Conversely, in action 416, if the UE does not pass the UAC mechanism, the UE may prohibit the SDT procedure for a period of time (e.g., a backoff period), and the time span of the period may be autonomously determined by the UE based on a given formula implemented in the UAC mechanism.

[0144] In some other embodiments, the UE only applies UAC for the RRCResumeRequest procedure (e.g., by reusing the access category for the RRC resume request while the UL packet (or uplink transport block) is multiplexed with the RRCResumeRequest message for transmission), and the decision may also apply to (small) packet transmissions. In other words, there may be no specific UAC mechanism for (small) packet transmissions. In some embodiments, the UE may perform the access control procedure until the SDT procedure is initiated. On the other hand, the UE may not perform the access control procedure during the SDT procedure. The access control procedure may be a general solution for the CG-SDT procedure and the RA-SDT procedure. In some implementations, the access control may be performed before the UE decides to apply the CG-SDT procedure or the RA-SDT procedure. After the UE passes the access control, the UE may decide to apply the type of SDT procedure to the RRC inactive state packet transmission. As explained above, the access control may be a mechanism used to determine whether the UE is allowed to perform a UL data transmission procedure (e.g., an SDT procedure) while the UE is in the RRC inactive state. A UE may be considered to pass access control (i.e., the UE is permitted to perform a UL data transmission procedure) when the UE meets a specific set of conditions including, for example, that UL data transmission attempts are not prohibited by the serving cell and the amount of pending UL data to be transmitted is less than or equal to a data volume threshold. In some other embodiments, the specific set of conditions may further include the UE passing a UAC mechanism.

[0145] FIG. 5 illustrates a flowchart for a method 500 of performing a UAC mechanism for SDT according to an implementation of the present disclosure. In some embodiments, before the apparatus 500 executes, the UE may have already received one or more configured parameters related to UAC from a serving cell. For example, the serving cell may configure the UE with parameters related to UAC for small packet transmission procedure (e.g., through broadcast system information). In addition, before the UE initiates an SDT procedure for small packet transmission, the UE may determine whether a pending packet to be transmitted can be directly transmitted through an SDT procedure. In other words, before the UE initiates an SDT procedure for small packet transmission, the UE may execute a UAC mechanism (e.g., as shown in FIG. 5) to determine whether a small packet to be transmitted can be directly transmitted through an SDT procedure. The UE may receive an information element 'UAC-BarringInfoSetList' from the serving cell, which includes parameters such as 'uac-BarringForAccessIdentity', 'uac-BarringFactor', and 'uac-BarringTime'. Furthermore, the access category may be further associated with a particular configuration provided by the serving cell. For example, the association may be determined by assigning a 'UAC-BarringInfoSetIndex' that is associated with a particular 'uac-BarringInfoSetList'. Also, note that the SDT procedure may be a CG-SDT procedure or a RA-SDT procedure (e.g., a 2-step / 4-step RA procedure). Also, note that in some embodiments, the UE may be configured with different access categories for the CG-SDT procedure or the RA-SDT procedure, respectively. In this state, the UE may be configured to first initiate one particular first type SDT procedure (e.g., a CG-SDT procedure), and thus the UE may perform a first UAC mechanism for the first type SDT procedure. Then, if the first type SDT procedure is prohibited by the first UAC result.The UE may consider selecting another type of SDT procedure (e.g., an RA-SDT procedure), and thus the UE may perform a second UAC mechanism for a subsequent RA-SDT procedure (e.g., a CG-SDT procedure is considered to be prohibited by the first UAC result).

[0146] In action 502, the UE can determine whether the UE is already remaining within a prohibition period caused by a previous access attempt with the serving cell, where the previous access attempt occurred earlier than the UE's access attempt to initiate an SDT procedure (e.g., a CG-SDT procedure or a RA-SDT procedure), and the previous access attempt and the UE's access attempt to initiate a UL data transmission procedure have the same access category (AC) in the UAC mechanism. In some embodiments, the previous access attempt may be the UE's previous attempt to initiate an SDT procedure (thus, in this state, the SDT procedure may have already been prohibited by the UE at least once in the past, and therefore the UE may need to check whether the prohibition period determined by the last failed attempt expires). In some other embodiments, the previous access attempt may not be an SDT procedure attempt, but another event that shares the same access category (e.g., RRC message delivery) as the SDT procedure in the UAC mechanism.

[0147] In a state while the active prohibition period is still counting, the UE may be prohibited from performing an SDT procedure until the prohibition period determined based on the UAC outcome of the previous access attempt has expired. In some embodiments, the UE may be allowed to initiate another UAC mechanism for an SDT procedure only when the prohibition period determined by the previous access attempt has expired.

[0148] When the prohibition period (affecting the SDT procedure) expires, in action 504, the UE may perform random number selection to generate a random number based on the UAC rule. The value of the random number may be in the range between [0,1]. Then, in action 506, the UE may determine whether the randomly selected number is less than or equal to uac-BarringFactor. Specifically, based on the access category, the UE may determine whether the UE is prohibited from small packet transmission by comparing the randomly selected number (determined in action 504) with a specific numerical value (e.g., uac-BarringFactor) received from the serving cell. The case where the randomly selected number is less than (or equal to) uac-BarringFactor means that the SDT procedure is allowed, and in action 508, the UE may initiate the SDT procedure in which the UE's pending packets are allowed to be transmitted by the UE in the RRC inactive state. In contrast, if the randomly selected number is greater than uac-BarringFactor, then in action 510, the UE may perform a prohibited time period determination and consider the SDP procedure to be prohibited from being performed for the prohibited time period.

[0149] Moreover, if a UE's access attempt is barred, the UE may also determine the time span for which small packet transmissions are prohibited by randomly selecting an initial value for timer T390 based on the following formula: T390=(0.7+0.6 * land) * uac-BarringTime(1) Here, rand means a random value selected between a given range (0,1). After determining the initial value of T390, the UE may start counting T390 to zero, and an access attempt (for small packet transmission) may be barred before the ongoing T390 expires. After T390 expires, the UE may execute the UAC mechanism again. The information elements {uac-BarringFactor, uac-BarringTime} for the SDT procedure may be determined by the access category of the SDT procedure (if it is set by the RAN / CN) or by the access category of the RRC message transmission.

[0150] In some other embodiments, the UE can determine whether the access attempt is barred by comparing the determined access identity with "uac-BarringForAccessIdentity" from the serving cell. For example, uac-BarringForAccessIdentity is a bitmap, where each bit in the bitmap directly maps to one Access Identity, and if the bit associated with the UE's Access Identity is set to 0, the access attempt (for small packet transmission) is allowed. If not (e.g., the bit associated with the UE's Access Identity information is set to "1"), which means the access attempt is barred for the UE, the UE may perform an access check and start counting T390 to 0.

[0151] In some embodiments, the UE may determine the pre-configured access identity. (For example, a Universal Subscriber Identity Module (USIM) equipped in the UE may indicate which access identity the UE should apply while the UE is triggered to transmit a small data packet via an SDT procedure.) In some embodiments, the UE may determine the access identity based on the service type (e.g., multimedia priority service (with access identity 1) or mission critical service (with access identity 2)) associated with a pending packet to be delivered through the SDT procedure.

[0152] In some embodiments, the UE may only apply UAC for the RRCResumeRequest procedure (by reusing the access category for the RRC resume request while the UL packet (or UL TB) is multiplexed with the RRCResumeRequest message for transmission), and the decision may also apply to (small) packet transmissions. In other words, there may be no specific UAC mechanism for (small) packet transmissions.

[0153] In some aspects of the present disclosure, the UE may not need to perform an access barring check while it is triggered to transmit uplink packets through an RA procedure (e.g., an RA-SDT procedure), which may be a two-step RA procedure or a four-step RA procedure.

[0154] In some aspects of the present disclosure, while a UE is triggered to transmit a UL packet via a UL-CG configuration (e.g., a CG-SDT procedure), it may not be necessary to perform an access barring check (e.g., method 500 illustrated in FIG. 5).

[0155] In some embodiments, it is predefined (e.g., predefined in a technical specification) that the UE does not need to perform an access barring check while the UE wishes to transmit an uplink packet through an RA procedure.

[0156] In some embodiments, the UE may also be configured to perform an access barring check while an RA procedure is triggered for small packet transmission. In some other embodiments, there may be a default setting preconfigured in the UE. For example, by default, the UE should perform an access barring check (e.g., as shown in FIG. 1) for small packet transmission via an RA procedure. Thus, explicit signaling (e.g., DL control signaling, DL-RRC signaling, or system information) can be configured in the UE to change the default setting. Otherwise, the UE can decide whether to trigger access barring based on the default setting and the serving cell, and the serving cell may not deliver DL-control signaling to change the default setting.

[0157] In some embodiments, the UE may not perform (eg, skip) the access barring check mechanism while an SDT procedure is triggered for a small packet transmission.

[0158] In some embodiments, the serving cell (e.g., while the UE remains in an RRC connected state) may configure the UE whether to skip or perform access barring checks via DL-RRC signaling, such as an RRC (access) release message or an RRC (connection) reconfiguration message.

[0159] In some other implementations, the serving cell (e.g., while the UE remains in an RRC connected, RRC inactive, or RRC idle state) may configure the UE to skip / perform the access barring check by system information delivery. The serving cell may send the system information to the UE via a broadcast approach or UE-specific DL control signaling (e.g., DL-RRC signaling such as an RRC (connection) reconfiguration message). In some additional embodiments, the UE may be configured (e.g., UE DL RRC signaling) to skip the access barring check (mechanism) for the CG-SDT or RA-SDT procedure. When the access barring check is skipped, the UE does not perform the access barring check.

[0160] In some embodiments, the UE may be pre-configured (e.g., the pre-configuration may be stored in a memory module on the UE side) to skip performing the access barring check mechanism for small packet transmissions. In some additional embodiments, the UE may be pre-configured to skip the access barring check mechanism for a CG-SDT procedure or a RA-SDT procedure.

[0161] In some aspects of the present disclosure, the UAC mechanism may be executed via a CG-SDT procedure or a UL-CG procedure.

[0162] For example, a UAC-like mechanism may be applied to the UE while it wants to transmit small packets through one or more UL-CG configurations. In other words, if the UAC outcome to the UE is forbidden, the UE is not allowed to perform / conduct (small) packet transmissions through the stored UL-CG configuration(s). Also, UL-CG transmissions may be forbidden while also counting a back-off timer (e.g., T390). The initial value of T390 may be part of the UAC outcome.

[0163] In some embodiments, a UE attempting to transmit a packet(s) via a pre-configured UL-CG configuration may be considered to generate an access attempt. Thus, the UAC mechanism may be reused when a UE (in an RRC inactive or RRC idle state) attempts to transmit a packet via one or more pre-configured UL-CG configurations.

[0164] In some embodiments, whether the UE needs to perform UAC for small packet transmissions may be configurable by accessing the UL-CG configuration.

[0165] In some embodiments, the UAC mechanisms that apply to the RA procedure may not apply to (small) packet transmissions over the UL-CG configuration. In such a situation, the UE may still be able to transmit (small) packets over the stored UL-CG configuration while the UAC outcome (related to the RA-SDT procedure) is "prohibited" and the back-off timer (e.g., T390) is still running / counting.

[0166] In some implementations, if the UE considers an access attempt associated with the serving cell to be barred (e.g., due to a UAC decision derived by other events such as an RNAU procedure, or while the UE is being triggered (by higher layers) for a new service request). The UE may also be directly disabled from (small) packet transmissions via RA procedures while being barred from initiating another access attempt to that serving cell (e.g., an SDT procedure, which may be a CG-SDT procedure or a RA-SDT procedure). In some other embodiments, the barring situation (e.g., an SDT procedure is affected by a previous other event) may only occur when the SDT procedure and the other event belong to the same access category in the UAC mechanism.

[0167] In some implementations, the UE may consider the cell to be barred for a period of time (e.g., by referencing a running T390). The UE is then barred from initiating an RA procedure (2-step / 4-step procedure) for small packet transmission before the running T390 expires. In other words, the UE may initiate an RA procedure for small packet transmission (only) after the counting T390 expires.

[0168] In some embodiments, the UE may initiate an RA procedure for small packet transmission without being affected by a previous UAC decision (even if the UE is still prohibited from initiating an RA procedure for an RNAU procedure). In other words, the access attempt(s) for small packet transmission may be independent for each RRC procedure (e.g., an RRC resume procedure), and thus the UE may perform a separate UAC mechanism for (small) packet transmission, and the UE may determine whether the (small) packet transmission via the RA procedure is allowed or prohibited by considering only the UAC decision triggered for the small packet transmission.

[0169] Furthermore, initiation of an RA procedure for a (small) packet transmission may not affect the counting period for which the UE considers itself "prohibited" from initiating an RA procedure for one RRC procedure (e.g., an RNAU procedure).

[0170] In such a situation, a pending RRC resume request message (if any) may not be allowed to be multiplexed with small packets before the T390 count (which is generated while access attempts for the RNAU procedure are prohibited) expires.

[0171] In some embodiments, the UE may be configured with prioritized RA parameters (e.g., as RA prioritization settings in TS38.331) for (small) packet transmission via the RA procedure. For example, the UE may be configured with at least one of the parameters PowerRampingSetupHighPriority, ScalingFactorBI, Preamblereceivedtargetpower, and PreambleTransMax: PowerRampingSetupHighPriority=ENUMERATED{dB0, dB2, dB4, dB6}. PowerRampingSetupHighPriority defines the ramping step applied to the prioritized RA procedure, where dB0 means 0 dB in each power ramping step, dB2 means 2 dB in each ramping step, etc. In this disclosure, "ENUMERATED{...}" represents a data type consisting of a set of named values ​​(e.g., dB0, dB2, dB4, and dB6 in the above example) defined by Abstract Syntax Notation One (ASN.1).

[0172] ScalingFactorBI=ENUMERATED{zero, dot25, dot5, dot75}. ScalingFactorBI defines the scaling factor for the backoff indicator for prioritized RA procedures (as specified in 3GPP TS38.321), where the value 0 corresponds to 0, the value dot25 corresponds to 0.25, and so on.

[0173] Preamblereceivedtargetpower=Integer (-202..-60). This parameter defines the target power at the network receiver side.

[0174] PreambleTransMax=ENUMERATED{n3, n4, n5, n6, n7, n8, n10, n20, n50, n100, n200}. This parameter defines the maximum number of RA preamble transmissions performed before declaring a failure.

[0175] In some embodiments, the RA-Prioritization setting for (small) packet transmissions (e.g., RA-Prioritization_ULPacket) may be configured in the UE through dedicated UE-specific control signaling (e.g., RRCReconfiguration message, RRCRelease message) or broadcast system information, or via SI delivery through UE-specific control signaling or an SI on demand procedure. In some embodiments, the preferred RA parameters may be configured via an RRCRelease ((RRC Configuration) Suspend Command or Suspend Configuration) message. In some embodiments, the preferred RA parameters may be included in the configuration for SDT. In some embodiments, the preferred RA parameters may be applied only if the UE is configured with the preferred RA parameters for (small) packet transmission and the UE meets the conditions for initiating an RA for (small) packet transmission. In one embodiment, the conditions for initiating an RA for (small) packet transmission may be due to incoming UL data while the UE is in RRC_INACTIVE state, the UL data available for transmission plus a MAC header, and if necessary, the MAC control element is smaller (or larger) than a data threshold indicated by the network.

[0176] In some embodiments, the configured parameter RA_prioritization_ULPacket may generally apply to 4-step RA procedures and 2-step RA procedures. In some other embodiments, RA_prioritization_ULPacket may only apply to 4-step RA procedures. Another parameter set "RA_Prioritization_ULPacket-2step" may also be configured to the UE for (small) packet transmission via 2-step RA procedures. RA_prioritization_ULPacket and RA_prioritization_ULPacket-2step may be configured to the UE jointly through the same approach. In some other embodiments, RA_prioritization_ULPacket and RA_prioritization_ULPacket-2step may be configured to the UE separately through different approaches.

[0177] In some embodiments, RA_prioritization_ULPacket settings associated with different access identities and / or different access categories may be delivered to the UE (through UE-specific RRC signaling or through (broadcast) system information). The UE may apply the RA_prioritization_ULPacket setting associated with the corresponding access identity (and / or) access category of the (small) packet transmission via the (2-step / 4-step) RA procedure. In some embodiments, an access identity bitmap (access_identity_bitmap) may be configured to be associated with the RA_prioritization_ULPacket setting, and each bit in the access_identity_bitmap may be predefined to be associated with one corresponding access identity. In some implementations, one access identity with RA prioritization may be configured by the serving cell by setting the corresponding bit in the bitmap to "1". Otherwise (no RA prioritization for the access identity), the serving cell may set the corresponding bit to "0".

[0178] A similar approach may be applied to RA prioritization for different access categories. For example, one access_category_Bitmap may be set to be associated with one RA_prioritization_ULPacket setting, and each bit in the access_category_Bitmap may be predefined to be associated with one corresponding access category. In some implementations, the serving cell may set one access category with RA prioritization by setting the corresponding bit in the bitmap to "1". Otherwise (no RA prioritization for the access category), the serving cell may set the corresponding bit to "0". In some embodiments, the Access_Category_Bitmap may be replaced by a Boolean array.

[0179] In some embodiments, there is one bit (e.g., RA_prioritization_up bit) or one Boolean value to be set to be associated with the RA_prioritization setting. The serving cell can configure the UE to prioritize the RA procedure (for small packet transmission) by setting the RA_prioritization_up bit = "1" (or "true"). After receiving the configuration, the UE may apply the RA_prioritization setting during the RA procedure (for small packet transmission) if RA_prioritization_up = "1" or "true". Otherwise (e.g., RA_prioritization_up is "0" or "false" or it is not set by the serving cell), the UE may not apply the RA_prioritization setting during the RA procedure (for small packet transmission). In some embodiments, the RA_prioritization_up bit may cover both 4-step / 2-step RA procedures (for small packet transmission). In some other embodiments, the RA_prioritization_up bit may cover the 4-step RA procedure (for small packet transmission).

[0180] In some other implementations, another bit (or Boolean value), such as RA_prioritization_up-2step, may also be set to be associated with the RA_prioritization setting (e.g., RA_prioritizationTwoStep, which defines the power ramping factor and BI scaling factor for the UE to perform a (prioritized) two-step RA procedure). RA_priotization_up-2step is set to enable / disable the UE from applying the RA_prioritization setting while the UE is performing a (small) packet transmission via a two-step RA procedure. After receiving the setting, the UE may apply the two-step RA procedure prioritization setting (for small packet transmission) if RA_prioritization_up="1" or "true". Otherwise (e.g., RA_prioritization_up is "0" or "false" or not set by the serving cell), the UE may not apply the RA priority procedure (e.g., RA_prioritizationTwoStep) during the two-step RA procedure (for small packet transmission).

[0181] In some embodiments, at least one of the parameters RA_prioritization_ULPacket setting and the parameter RA_prioritization_ULPacket-2step setting may be associated with a different logical channel (LCH) that initiates the RA procedure. For example, when a 4-step RA procedure is initiated, the UE may apply the RA_prioritization_ULPacket setting associated with the corresponding LCH that has pending update data for SDT. In another example, when a 2-step RA procedure is initiated, the UE may apply the RA_prioritization_ULPacket-2step setting associated with the corresponding LCH that has pending UL data for SDT.

[0182] In some cases, the UE may receive two configurations for the same application (e.g., RA_prioritization_ULPacket and RA_prioritization_ULPacket-2step configurations) via system information broadcast by the network and / or via UE-specific dedicated control signaling (e.g., UE-specific (DL) RRC signaling), respectively. In such cases, the configuration received via the UE-specific dedicated control signaling may have a higher priority. The UE may apply the configuration received via the UE-specific RRC signaling rather than the configuration received via the (broadcast) system information. In some embodiments, the UE may apply the configuration received via the (broadcast) system information while the configuration received via the UE-specific RRC signaling is deleted (or invalid).

[0183] In some embodiments, the UE may reuse the existing signaling and RA prioritization approach by reusing the existing mechanism. It means that the existing RA prioritization indication (and rules) are applied to the UE to implement the (small) packet transmission via the (2-step / 4-step) RA procedure. The UE may be configured with different RA_prioritization_ULPacket settings for (small) packet transmission on the SUL or UL component carrier, respectively. In some embodiments, different RA_prioritization parameters may be configured to be associated with different logical channels (or different RLC bearers) for small packet transmission. Thus, while the UE initiates the RA procedure for (small) packet transmission, the UE may determine the RA_prioritization parameter based on the corresponding logical channel (on which pending packets are multiplexed for transmission). The UE may determine the RA_Prioritization parameter based on the priority of the corresponding logical channel (e.g., the priority of the configured corresponding logical channel, which may be configured in the SDT configuration).

[0184] The concept of power ramping may also be applied to (small) packet transmission via a stored UL-CG configuration. For example, a parameter ''PowerRamping_CG'' is configured in the UE for (small) packet transmission via a UL-CG configuration. Each time the UE receives one HARQ NACK message from the serving cell (and / or DTX, meaning that the UE does not receive a HARQ feedback message from the serving cell after a packet transmission via the stored UL-CG configuration), the UE may increase the transmit (Tx) power in the next transmission by one step further based on the parameter PowerRamping_CG. The power ramping procedure may be performed continuously until the UE reaches a maximum number of UL packet retransmissions or a maximum UL Tx power threshold is reached.

[0185] In some aspects of the present disclosure, at least one data amount threshold (D) for the UE is used to determine whether the UE should initiate an RA procedure (e.g., a two-step or four-step procedure) and / or access one (or more) UL-CG configurations for small packet transmission. Low The UE may be configured using broadcast system information with or without SI on demand procedure, UE specific dedicated control signaling (e.g., RRCRelease message or RRCReconfiguration message with suspend configuration), physical control signaling (e.g., DCI) predefined in the technical specification or preinstalled in the USIM, and / or MAC control element. Low In some implementations, the value of D Low may be in units, for example, bytes or bits. In some implementations, D Low The value of may be part of the SDT configuration sent by the serving cell via the RRCRelease message.

[0186] In some embodiments, the UE may calculate the total pending data volume by considering only the logical channels that are enabled / allowed / configured for the SDT procedure. In addition, the UE may calculate the pending data volume of one logical channel based on a conventional approach when the UE is calculating the buffer status of one logical channel (e.g., by referring to 3GPP TS38.322 and 38.323). The pending data volumes of all Data Radio Bearers (DRBs) and all Signaling Radio Bearers (SRBs) enabled for SDT may be jointly considered for the access control mechanism while one or more DRBs / SRBs are enabled for SDT procedure. In some additional embodiments, the pending volumes of all DRBs enabled for SDT may be counted independently from the pending volumes of all SRBs enabled for SDT, and an independent data volume threshold (D Low ) may be configured in the UE for the amount of reserved data for the DRB and another for the amount of reserved data for the SRB, respectively. In this state, action 506 in FIG. 5 may be performed only for the DRB or only for the SRB.

[0187] In some embodiments, D Low and the access control measures / evaluates / calculates / estimates the reserved packet volume (e.g., the total TB allowed to be transmitted through the proposed small packet transmission) and sets the total volume to D Low The UE may compare the amount of pending packets with D Low If the total amount of pending packets allowed to be transmitted via the proposed small packet transmission in the MAC entity is greater than (or equal to) D, then it may be allowed (or enabled / configured) to initiate a (2-step / 4-step) RA procedure (or one UL-CG access attempt to access the UL-CG configuration). Conversely (e.g., if the total amount of pending packets allowed to be transmitted via the proposed small packet transmission in the MAC entity is greater than D, then it may be allowed (or enabled / configured) to initiate a (2-step / 4-step) RA procedure (or one UL-CG access attempt to access the UL-CG configuration). Low , the UE is not allowed to initiate a (2-step / 4-step) RA procedure (or a UL-CG access attempt) for small packet transmission.

[0188] In contrast (e.g., D Low (or equal to) the total amount of pending packets in the MAC entity), the UE is not allowed to initiate a (2-step / 4-step) RA procedure (and / or a UL-CG access attempt) for small packet transmission. Pending packets may still be able to be transmitted through an RA procedure (or a UL-CG access attempt) initiated by other triggering events.

[0189] In some embodiments, the UE may transmit pending packets if an RA procedure or UL-CG access attempt is triggered due to other events (the total amount of pending data is D Low For example, while an RA procedure (or a UL-CG access attempt) is triggered by an RRC signaling transmission, the UE may still be able to multiplex pending packets with an RRCResumeRequest message for small packet transmission.

[0190] In some embodiments, the UE Low In some other implementations (e.g., D Low is not set or D Low is set to a very large value, such as infinity), this means that the MAC entity is necessarily disabled from directly initiating an RA procedure (and / or a UL-CG access attempt) (e.g., in other words, pending packets of the logical channel may only be multiplexed with RRC signaling while an RA or UL-CG access attempt is initiated).

[0191] In some embodiments, D Lowmay be associated with a logical channel (or may be associated with a radio bearer such as a DRB or SRB). In the MAC entity, the UE may measure / evaluate / calculate / estimate the total amount of pending packets for one logical channel (for which packets associated with the logical channel are allowed to be transmitted while the UE remains in the RRC inactive state). Then, the total amount of pending packets for one (or more) considered logical channels (e.g., D Low The amount of pending packets in the logical channel (configured using Low If , the UE may be allowed to initiate a (2-step / 4-step) RA procedure (or UL-CG access attempt) for small packet transmission.

[0192] In contrast (e.g., if the amount of pending packets is D Low (logical channels larger than (or equal to) are not considered), the UE is not allowed to initiate a (2-step / 4-step) RA procedure (or UL-CG access attempt) for small packet transmission. Note, however, that these pending packets may still be able to be transmitted through RA procedures (or UL-CG access attempts) initiated by other triggering events.

[0193] In some embodiments, if an RA procedure or UL-CG access attempt is triggered due to other events, the UE may not be able to receive pending packets of a logical channel (e.g., an associated D Low Even if the amount of pending data on LCH#1 is smaller than the amount of pending data on LCH#1, it may still be possible to transmit LCH#1.

[0194] For example, the UE may be able to multiplex pending packets of a logical channel (e.g., LCH#1) with RRC control signaling (e.g., RRCResumeRequest message) for small packet transmission while an RA procedure (or UL-CG access attempt) is triggered by an RRC signaling transmission. For example, the UE may be able to multiplex pending packets of a logical channel (e.g., LCH#1) with RRC control signaling (e.g., RRCResumeRequest message) for small packet transmission while an RA procedure (or UL-CG access attempt) is triggered by an RRC signaling transmission ... Low , pending packets of LCH#1 can be multiplexed with pending packets of other logical channels (eg, LCH#2).

[0195] In some embodiments, the logical channel is D Low In some other implementations (e.g., D Low is not set or is set to a very large value such as infinity. Low is set), which necessarily disables the UE from directly initiating an RA procedure (and / or initiating a UL-CG access attempt) (e.g., in other words, pending packets of a logical channel can only be multiplexed with packets of other logical channels while an RA or UL-CG access attempt is initiated).

[0196] In some embodiments, D Lowmay be associated with one logical channel group (e.g., one logical channel group may be configured by the serving cell to include one or more logical channels). In the MAC entity of the UE, the UE may measure / evaluate / calculate / estimate the total amount of pending packets of one logical channel group (the packets associated with which are allowed to be transmitted while the UE remains in the RRC inactive state). Then, the UE may measure / evaluate / calculate / estimate the total amount of pending packets of one (or more) considered logical channel groups (e.g., D Low The total number of pending packets in the logical channel (configured by Low If , the UE may be allowed to initiate a (2-step / 4-step) RA procedure (or UL-CG access attempt).

[0197] In contrast (e.g., D related to a logical channel group where the total number of pending packets is taken into account) Low If there is no considered logical channel group larger than (or equal to) , the UE may not be allowed to initiate a (2-step / 4-step) RA procedure (and / or UL-CG access attempt) for small packet transmission. Pending packets may still be able to be transmitted through RA procedures (or UL-CG access attempts) initiated by other triggering events.

[0198] In some embodiments, when the UE determines that an RA procedure or a UL-CG access attempt is triggered due to other events, it may notify the UE of pending packets of a logical channel group (e.g., pending data amount of LCG#1) related to the D LowFor example, the UE may still be able to multiplex pending packets of a logical channel (e.g., LCH#1) with an RRCResumeRequest message for small packet transmissions while an RA procedure (or UL-CG access attempt) is triggered by an RRC signaling transmission. ...CG#2) with an RRCResumeRequest message for small packet transmissions while an RA procedure (or UL-CG access attempt) is triggered by an LCG#2 (e.g., the amount of pending data of LCG#2 is less than the amount of pending data of the D associated with LCG#2). Low , it may still be possible to multiplex pending packets of LCG#1 with pending packets of other logical channels (e.g., LCG#2).

[0199] In some embodiments, the logical channel group is D Low (or may be set to zero, "0") using D, which may indicate that the UE is enabled to initiate an RA procedure (and / or a UL-CG access attempt) while a new data packet arrives on the logical channel from a higher layer (e.g., the Radio Link Control (RLC) layer). Low is not set or is set to a very large value such as infinity), this means that the UE is never able to directly initiate an RA procedure (and / or a UL-CG access attempt) (in other words, pending packets of a logical channel group can only be multiplexed with packets of other logical channel groups while an RA or UL-CG access attempt is initiated).

[0200] In some embodiments, the logical channel group is defined by reusing the logical channel group of the buffer status report. In some other embodiments, the serving cell may configure a specific logical channel group for the measurement of the amount of pending packets. In addition, the UE may receive the LCG configuration through RRC signaling (e.g., in the suspend configuration in the RRCRelease message).

[0201] In some embodiments, different D Low For example, D for UE / logical channel / logical channel group can be set to Low The values ​​of D may be different from each other. For example, different D may be used for one UE to decide whether the UE should initiate a 4-step RA procedure / 2-step RA procedure / UL-CG access attempt. Low For example, different D Low may be configured to be associated with different RACH resource configurations, covering normal uplink carriers and auxiliary uplink carriers. For example, different D Low may be configured to cover normal uplink carriers and auxiliary uplink carriers.

[0202] As described in this disclosure, a solution is provided for a UE to perform (small) packet transmission while the UE remains in an RRC inactive state (or an RRC idle state). The UE described in this disclosure may perform any combination of the mechanisms / methods described in this disclosure. The parameters described in this disclosure may be considered as part of the UL-CG configuration or physical resource configuration of the RA procedure for (small) packet transmission while the UE remains in an RRC inactive state. The parameters may also be area specific, which may be configured with one effective area together with the UL-CG configuration or physical resource configuration of the RA procedure.

[0203] In some embodiments, the parameters or settings that the UE is configured for small packet transmission (e.g., UL-CG settings, RACH resource settings for small packet transmission, and / or parameters proposed in this disclosure) (any subset of) may still be retained after the UE transitions from an RRC inactive state to an RRC connected state. Furthermore, the stored parameters or settings may still be valid for small packet transmission while the UE switches from an RRC connected state to an RRC inactive state again (e.g., if the serving cell does not command the UE to release the stored parameters / settings and / or if the serving cell does not send new parameters / settings for the UE to replace the stored parameters / settings). In some implementations, the described mechanisms may be applied to mobility events in various RRC states, such as a cell (re)selection procedure or a (conditional) handover procedure. Further, in some embodiments, the stored parameters / settings may be valid in a UE-specific / cell-specific area, which may be defined by at least one of a cell identity, a physical cell identity (PCI), a RAN area ID, a RAN notification area code (RNAC), a tracking area code (TAC), or a system information area ID (e.g., a system information area ID). In some embodiments, the parameters / settings stored by the UE may be automatically deleted (or released) while the UE leaves the validity area associated with the stored parameters / settings due to a mobility event in various RRC states (e.g., cell (re)selection, handover, conditional handover, RRC (re)establishment procedure). In some embodiments, the stored parameters / settings may be released by the UE moving to another RA (e.g., E-UTRA) or changing the SNPN access mode (e.g., when the UE moves to or leaves the SNPN access mode).

[0204] In some embodiments, various combinations of the described embodiments may be made to formulate a two-tier (or multi-tier) access control mechanism for small packet transmissions (e.g., while the UE remains in an RRC inactive state).

[0205] FIG. 6 illustrates a flowchart of a method 600 that a UE performs for access control, according to one embodiment of the present disclosure. Although actions 602 and 604 are illustrated as separate actions depicted as independent blocks in FIG. 6, these separately illustrated actions should not necessarily be construed as order dependent. The order in which the operations are performed in FIG. 6 is not intended to be construed as limiting, and any number of the disclosed blocks may be combined in any order to perform the method, or alternative methods. Additionally, each of actions 602 and 604 may be performed independently of the other actions and may be omitted in some embodiments of the present disclosure.

[0206] At action 602, the UE may receive and store a radio resource configuration from the serving cell (e.g., while the UE remains in an RRC connected state with the serving RAN, which may be an E-UTRAN or an NR-RAN) while attempting to initiate a UL data transmission procedure with the serving cell during the UE's RRC inactive state. Then, after the UE moves to the (LTE / NR) RRC inactive state, the UE may be able to initiate a UL data transmission procedure with the serving RAN based on the stored radio resource configuration. For example, the UE may initiate a UL data transmission procedure to perform a (small) packet transmission in the RRC inactive state.

[0207] In action 604, the UE attempts to initiate a UL data transmission procedure with the serving cell during the UE's RRC inactive state, and the UE can transmit one or more UL packets to the serving cell based on the radio resource configuration when multiple conditions are met. In other words, the UE is allowed to perform the UL data transmission procedure when multiple conditions are met. The multiple conditions include that the UL data transmission attempt is not prohibited by the serving cell and the amount of pending UL data to be transmitted is less than or equal to a data amount threshold.

[0208] In some embodiments, the UL data transmission procedure is an RA procedure (eg, a 2-step / 4-step RA procedure) that is triggered by the UE based on a radio resource configuration.

[0209] In some embodiments, the UL data transmission procedure includes (by the UE) accessing at least one UL-CG based on a UL-CG configuration preconfigured by the serving cell via UE specific control signaling.

[0210] In some implementations, a UL data transmission attempt may be barred when system information is received from a serving cell including a cell barred bit (e.g., the cellBarred bit described above) indicating that the serving cell is barred, or when an access attempt (e.g., an SDT procedure or another access attempt that may have the same access category as the SDT procedure) related to the serving cell is barred for a barring period determined by the UE based on the outcome of the UAC mechanism. When a UE's UL data transmission attempt is barred, it means that even if the UE has a pending packet to be transmitted and attempts to transmit the pending packet, the UE is prohibited from performing a UL data transmission.

[0211] In some embodiments, a UAC mechanism may be performed by (or "performed by") the UE for a UL data transmission procedure (e.g., an SDT procedure, or an access attempt with the serving cell, such as an initial access attempt) based on an access category associated with the UL data transmission procedure. In some embodiments, the UE may perform / execute the UAC mechanism by comparing a randomly selected number with a unique value (e.g., uac-BarringFactor) received from the serving cell (as shown). If the randomly selected number is smaller (or equal) to a certain value, the UE passes the UAC test and is deemed to be allowed to perform the UL data transmission procedure. If the randomly selected number is larger than a certain value, the UE fails the UAC test and the UL data transmission procedure is prohibited for a period of time, which time span may be randomly determined by the UE within a given range as part of the UAC mechanism.

[0212] In some embodiments, the UE may not perform another UAC mechanism for an access attempt of a UL data transmission procedure until the prohibition time has elapsed.

[0213] In some embodiments, the UE may receive the data amount threshold via UE-specific RRC signaling or via broadcast system information.

[0214] In some embodiments, the UE may determine the amount of pending UL data (e.g., the total number of pending packets at the UE) by only considering the pending data in all of the multiple logical channels allowed by the serving cell for UL data transmission during the RRC inactive state.

[0215] 7 illustrates a flow chart of a method 700 for access control according to one embodiment of the present disclosure. Method 700 may be performed independently or in combination with other methods described in this disclosure.

[0216] At action 702, the UE may determine whether to initiate an SDT procedure for uplink data transmission based on a data amount threshold.

[0217] At action 704, if the pending amount is less than (or equal to) the data amount threshold, the UE may initiate a CG-SDT / RA-SDT procedure.

[0218] 8 illustrates a flowchart of a method 800 for access control according to an embodiment of the present disclosure. The method 800 may be performed independently or in combination with other methods described in this disclosure.

[0219] At action 802, the UE may determine whether to access at least one UL-CG for UL data transmission based on the first data amount threshold. For example, the UE may determine whether to initiate a CG-SDT procedure for UL data transmission (e.g., by accessing at least one UL-CG stored in an SDT configuration) based on the first data amount threshold. In some embodiments, the UE may determine not to initiate a CG-SDT procedure at action 802 if at least one of the following events (1) and (2) occurs: (1) The pending data amount is greater than (or equal to) the stored first data amount threshold (set for the CG-SDT procedure). (2) There is no appropriate UL-CG resource configuration for the SDT procedure (e.g., the UE performs a DL-RSRP measurement associated with a stored UL-CG configuration (e.g., by measuring a DL-SSB set associated with the UL-CG configuration), and the measurement result of the UL-CG configuration is lower than a given DL-RSRP threshold associated with the UL-CG configuration).

[0220] In some other embodiments, a CG-SDT procedure may be initiated in action 802, but the initiated CG-SDT procedure may fail (e.g., the UE reselects to another cell during the CG-SDT procedure, the number of ARQ retransmissions (for one RLC packet) reaches a maximum threshold during the CG-SDT procedure, the TAT_Inactive associated with the CG-SDT procedure expires), etc. In this state, the UE may then move to action 804.

[0221] In action 804, the UE may determine whether to initiate an RA procedure for uplink data transmission based on the second data volume threshold. For example, the UE may determine whether to initiate an RA-SDT procedure if the total pending volume is equal to or less than the second volume threshold. In some embodiments, the first data volume threshold and the second data volume threshold are independently configured in the UE. In some other embodiments, the first data volume threshold setting and the second data volume threshold setting may be the same data volume threshold setting. In some embodiments, the UE may only execute one access control mechanism in action 802 (to determine whether to initiate a CG-SDT procedure based on the result of the proposed access control mechanism). In addition, the UE may skip the access control mechanism in action 804 if the UE has already passed in action 802. In other words, the UE does not apply the access control mechanism for the RA-SDT procedure if the RA-SDT procedure is triggered after a failed CG-SDT procedure or after a "prohibited" CG-SDT access attempt.

[0222] The following may be used to further disclose terms, examples, embodiments, implementations, actions, and / or behaviors: The terms network (NW), radio access network (RAN), cell, camped cell, serving cell, base station, gNB, eNB, and ng-eNB may be used interchangeably in this disclosure. In addition, some of the terms may refer to the same network entity.

[0223] Serving cell: For a UE in RRC_connected (i.e., RRC connected state) without CA / DC configured, there is only one serving cell, including the primary cell. For a UE in RRC_CONNECTED with CA / DC configured, the term "serving cell" is used to denote the set of cells, including the special cell and all secondary cells.

[0224] Special cell: In case of dual connectivity operation, the term special cell refers to a PCell in the MCG or a PSCell in the SCG; otherwise, the term special cell refers to a PCell.

[0225] The proposed mechanism may be applied to any RAT, which may be (but is not limited to) NR, NR-U, LTE, E-UTRA connected to 5GC, LTE connected to 5GC, E-UTRA connected to EPC, and LTE connected to EPC. The proposed mechanism may be applied to UEs in a public network or in a private network (e.g., NPN (Non-Public Network), SNPN (Standalone NPN), PNI-NPN (Public Network Integrated NPN)).

[0226] The mechanisms described in this disclosure may be applied to licensed frequencies and / or dark licensable frequencies.

[0227] System information (SI) may refer to MIB, SIB1, and other SI. The minimum SI may include MIB and SIB1. Other SI may refer to SIB3, SIB4, SIB5, and other SIB(s) (e.g., SNPN-specific SIB, PNI-NPN-specific SIB).

[0228] The dedicated signal may refer to (but is not limited to) an RRC message, such as an RRC(Connection)SetupRequest message, an RRC(Connection)SetupComplete message, an RRC(Connection)Reconfiguration message, an RRC Connection Reconfiguration message with mobility control information, an RRC Reconfiguration message without mobility control information therein, an RRC Reconfiguration message with synchronization therein, an RRC(Connection)ReconfigurationComplete message, an RRC(Connection)ResumeRequest message, an RRC(Connection)Resume message, an RRC(Connection)ResumeComplete message, an RRC(Connection)ReestablishmentRequest message, an RRC(Connection)Reestablishment message, an RRC(Connection)ReestablishmentComplete message, an RRC(Connection)Reject message, an RRC(Connection)Releasemessage message, an RRC System information Request message, a UE AssistanceInformation message, a UE CapabilityEnquiry message, and a UE CapabilityInformation message. An RRC message may be a type of dedicated signal. The UE may receive RRC messages from the network via unicast / broadcast / groupcast.

[0229] RRC_connected UEs (i.e., UEs in an RRC connected state), RRC_inactive UEs (i.e., UEs in an RRC inactive state), and RRC_idle UEs (i.e., UEs in an RRC idle state) may apply the embodiments described in the present disclosure.

[0230] An RRC_CONNECTED UE may be configured with an active BWP with a common search space configured to monitor system information or paging.

[0231] The described mechanism may be applied to the PCell and the UE. In some embodiments, the described mechanism may be applied for the PSCell and the UE. The short message and / or the paging DCI may be transmitted by the PSCell (or the secondary node) to the UE. The UE may monitor the PDCCH monitoring opportunities for paging configured by the PSCell (or the secondary node).

[0232] In the presented embodiment, if the UE considers itself barred by a cell, or if the UE barred the cell, or if the UE is barred from initiating one particular service with the serving cell, the UE may bar the cell for a period of time (e.g., 300s). The UE cannot consider the cell as a candidate cell for cell (re)selection for the period of time (e.g., 300s).

[0233] In the presented implementation, when the UE changes from SNPN access mode to PLMN access mode, the UE's (NAS entity) may release (or delete) the (stored or maintained) list of SNPN IDs (if any).

[0234] In the presented embodiment, when the UE changes from PLMN access mode to SNPN access mode, the (NAS entity of) the UE may release (or delete or discard) the (stored or maintained) list of PLMN IDs, if present.

[0235] Downlink control will be described. DCI can refer to a PDCCH resource with a Cyclic Redundancy Check (CRC) scrambled by a Radio Network Temporary Identifier (RNTI). Alternatively, the DCI embodiment can be applied to a physical signal.

[0236] NR supports the RRC_INACTIVE state, and UEs with infrequent (periodic and / or aperiodic) data transmissions are generally maintained by the network in the RRC_INACTIVE state. Until Rel-16, the RRC_INACTIVE state does not support data transmission. Thus, the UE must resume access (i.e., transition to the RRC_CONNECTED state) for any DL reception and / or UL data transmission. A connection setup and subsequent release to the inactive state is performed for each data transmission, regardless of how small and infrequent the data packets are. This results in unnecessary power consumption and signaling overhead.

[0237] Signaling overhead from (RRC) INACTIVE UEs due to transmission of small data packets is a common issue and becomes a significant issue as the number of UEs increases in NR, not only for network performance and efficiency, but also for UE battery performance. In general, devices with intermittent small data packets in INACTIVE state can benefit from enabling SDT in INACTIVE.

[0238] The key enablers for SDT in NR, i.e. inactive state, 2-step, 4-step RACH, and configured authorization type 1, are already specified as part of the legacy. Therefore, this work builds on these building blocks to enable SDT in the inactive state for NR.

[0239] RRC_inactive (i.e., RRC inactive state) is a state in which the UE remains CM-CONNECTED and can move within the area established by the NG-RAN (RNA) without informing the NG-RAN. In RRC_INACTIVE, the last serving gNB node (i.e., the anchor node to the UE) maintains the UE context and UE-associated NG connection with the serving AMF and UPF.

[0240] The RRC_INACTIVE state supports at least one of the following features: 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 for RAN paging configured by NG-RAN, 5GC-NG-RAN connection (both C / U-plane) established for the UE, UE AS context stored in the NG-RAN, and / or UE, the NG-RAN knows the RNA to which the UE belongs, etc.

[0241] For NR connected to 5GC, the UE identity "I-RNTI" may be used to identify the UE context in RRC_INACTIVE. The I-RNTI provides the new NG-RAN node with a reference to the UE context in the old NG-RAN node. How the new NG-RAN node can resolve the old NG-RAN ID from the I-RNTI is a matter of appropriate configuration in the old and new NG-RAN nodes. Some typical divisions of the 40-bit I-RNTI assume the following contents: UE-specific criteria: criteria to a UE context within a logical NG-RAN node; NG-RAN node address index: information for identifying the NG-RAN node that assigned the UE specific part; PLMN Specific Information: Information supporting network sharing deployment that provides an index into the PLMN ID portion of the global NG-RAN node identifier.

[0242] SNPN-specific information: An SNPN may be a small PLMN configured by an operator. Each SNPN may be identified by a unique SNPN identity (e.g., an identifier for the SNPN comprising a combination of a PLMN ID and a NID). Configured permission settings may be associated with the SNPN ID.

[0243] UE Inactive AS Context: The UE Inactive AS Context is stored when access is interrupted (when the UE is in RRC_Inactive state) and restored when access is resumed (e.g., when the UE transitions from RRC_Inactive state to RRC_CONNECTED state). In some embodiments, (part of) the configured SDT configuration may also be part of the UE inactive AS context (or part of the configured SDT configuration may be derived from the UE inactive AS context). In some other embodiments, (part of) the configured SDT configuration may be independent of the UE inactive AS context.

[0244] Suspension of RRC connection is initiated by the network. When RRC access is suspended, the UE stores the UE Inactive AS context and any configuration received from the network and transitions to RRC_Inactive state. If the UE is configured with SCG, the UE releases or suspends the SCG configuration when it initiates the RRC connection resumption procedure. The RRC messages for suspending RRC access are integrity protected and encrypted. Resumption of suspended RRC access is initiated by the above layers when the UE needs to transition from RRC_INACTIVE state to RRC_CONNECTED state, or by the RRC layer to perform an RNA update, or by RAN paging from NG-RAN. When the RRC connection is resumed, the network configures the UE according to the RRC connection resumption procedure based on the stored UE inactive AS context and any RRC configuration received from the network. The RRC connection resumption procedure reactivates AS security and reestablishes SRBs and DRBs.

[0245] In response to the request to resume the RRC connection, the network can either resume the suspended RRC access and send the UE to RRC_CONNECTED, or reject the resume request and send the UE to RRC_INACTIVE (with a waiting timer), or directly resuspend the RRC connection and send the UE to RRC_INACTIVE, or directly release the RRC connection and send the UE to RRC_IDLE, or command the UE to initiate NAS level recovery (in this case the network sends an RRC SETUP message).

[0246] In addition, in RRC_Inactive, UE-specific DRX may be configured by higher layers or by the RRC layer, UE controlled mobility is based on network configuration, the UE stores UE inactive AS context, and RAN-based notification area is configured by the RRC layer. Furthermore, the UE can perform the following behaviors in the RRC_INACTIVE state: Monitoring of short messages sent using P-RNTI on DCI; Monitoring of paging channel for CN paging using 5G-S-TMSI and RAN paging using full I-RNTI; Measurement of neighboring cells and performing cell (reselection); Performing RAN-based notification area updates periodically and when moving outside the configured RAN-based notification area Can get system information and submit SI requests (if configured).

[0247] In the UL, the gNB can dynamically allocate resources to the UE via the C-RNTI on the PDCCH. When the UE has its downlink reception enabled (when configured, activity governed by DRX), it constantly monitors the PDCCH to find possible UL grants / DL allocations for uplink transmission / DL reception. When CA is configured, the same C-RNTI applies to all serving cells.

[0248] Also, using configured grants, the gNB can allocate uplink resources for an initial HARQ transmission to the UE. Two types of configured uplink grants are defined: In type 1, the RRC directly provides the configured uplink grant (including the periodicity).

[0249] In Type 2, the RRC defines the period of the configured uplink grant, while the PDCCH addressed to the CS-RNTI signals the configured uplink grant and can activate or deactivate it, i.e., the PDCCH addressed to the CS-RNTI indicates that the uplink grant can be implicitly reused according to the period defined by the RRC until it is deactivated.

[0250] Type 1 and Type 2 are configured by the RRC per serving cell and per BWP. Multiple configurations can only be activated simultaneously on different serving cells. For Type 2, activation and deactivation are independent between serving cells. For the same serving cell, a MAC entity is configured with either Type 1 or Type 2.

[0251] The RRC configures the following parameters when grant type 1 is configured: cs-RNTI: CS-RNTI for retransmission; period: the period of the configured grant type 1; timeDomainOffset: The offset of the resource relative to SFN=0 in the time domain; timeDomainAllocation: Allocation of configured uplink grants in the time domain including startSymbolAndLength (i.e., SLIV in TS 38.214) nrofHARQ-Processes: The number of HARQ processes for the configured grant.

[0252] Upon configuration of a configured grant type 1 for the serving cell by higher layers, the MAC entity shall store the uplink grant provided by higher layers as the configured uplink grant for the indicated serving cell and / or shall initiate or restart the configured uplink grant at symbols according to timeDomainOffset and S (derived from SLIV as specified in TS 38.214) and reoccur with periodicity.

[0253] Regarding the RA procedure, two types of RA procedures are supported: a 4-step RA type (with MSG1) (e.g., CFRA and / or 4-step CBRA) and a 2-step RA type (with MSGA) (e.g., 2-step CFRA and / or 2-step CBRA).

[0254] Four RA types using MSG1 and two RA types using MSGA are supported. Both types of RA procedures support Contention-Based Random Access (CBRA) and Contention-Free Random Access (CFRA).

[0255] The UE may select the type of RA at the start of an RA procedure (e.g., for an SDT procedure) based on network configuration.

[0256] For example, if CFRA resources are not configured, the RSRP threshold is used by the UE to select between the 2-step RA type and the 4-step RA type. If CFRA resources for the 4-step RA type are configured, the UE performs RA of the 4-step RA type, and if CFRA resources for the 2-step RA type are configured, the UE performs RA of the 2-step RA type.

[0257] The network cannot configure CFRA resources for 4-step and 2-step RA types simultaneously for a certain BWP (bandwidth portion). CFRA with 2-step RA type is only supported for handover.

[0258] The two-step RA type MSGA includes a preamble on PRACH and a payload on PUSCH. After MSGA transmission, the UE monitors for a response from the network within a configured window. In case of CFRA, if a network response is received, the UE terminates the RA procedure. In case of CBRA, if contention resolution is successful upon reception of the network response, the UE terminates the RA procedure and if a fallback indication is received in MSGB, the UE performs an MSG3 transmission and monitors contention resolution. If contention resolution is not successful after MSG3 (re)transmission, the UE reverts to MSGA transmission.

[0259] If the RA procedure with a 2-step RA type is not completed after several MSGA transmissions, the UE may be configured to switch to CBRA with a 4-step RA type.

[0260] For cells configured with SUL, the network may explicitly signal which carrier to use (UL or SUL). Otherwise, the UE selects the SUL carrier only if the measured DL quality is lower than the broadcast threshold. The UE performs carrier selection before choosing between 2-step and 4-step RA types. The RSRP threshold for selecting between 2-step and 4-step RA types can be configured separately for UL and SUL. Once initiated, all uplink transmissions for the RA procedure remain on the selected carrier.

[0261] Based on the 3GPP specifications, when the UE wants to initiate an access attempt at one of the events defined in the 3GPP specifications (e.g., 3GPP TS 24.501), the UE determines one or more access identities from a set of standardized access identities and one access category from a set of standardized access categories and an operator-defined access category to be associated with the access attempt. In some embodiments, the UE may be configured with a unique access identity for an SDT procedure. In some other embodiments, the UE may reuse one existing access identity information as indicated in the 3GPP specifications (e.g., 3GPP TS 24.501) for the UAC mechanism of one SDT procedure (e.g., one CG-SDT procedure or one RA-SDT procedure).

[0262] Similarly, in some embodiments, the UE may be configured with one unique access category for SDT procedures, while in some other embodiments, the UE may reuse one existing access category as set forth in 3GPP specifications (e.g., 3GPP TS 24.501) for the UAC mechanism of one SDT procedure (e.g., one CG-SDT procedure or one RA-SDT procedure).

[0263] Figure 9 is a block diagram illustrating a node 900 for wireless communication according to one embodiment of the disclosure. As shown in Figure 9, the node 900 may include a transceiver 920, a processor 928, a memory 934, one or more presentation components 938, and at least one antenna 936. The node 900 may also include a radio frequency (RF) spectrum band module, a BS communication module, a network communication module, a system communication management module, an input / output (I / O) port, I / O components, and a power source (not shown in Figure 9).

[0264] Each of the components may communicate directly or indirectly with each other via one or more buses 940. The node 900 may be a UE or a BS that performs the various functions disclosed with reference to FIGS.

[0265] The transceiver 920 has a transmitter 922 (e.g., transmit / transmit circuitry) and a receiver 924 (e.g., receive / receive circuitry) and may be configured to transmit and / or receive time and / or frequency resource partitioning information. The transceiver 920 may be configured to transmit in different types of subframes and slots, including, but not limited to, usable, unavailable, and flexibly usable subframe and slot formats. The transceiver 920 may be configured to receive data channels and control channels.

[0266] The node 900 may include a variety of computer-readable media. The computer-readable media may be any available media that can be accessed by the node 900 and may include volatile (and / or non-volatile memory) and removable (and / or non-removable) media.

[0267] Computer-readable media may include computer storage media and communication media. Computer storage media may include both volatile and nonvolatile media, as well as removable and non-removable media implemented in any method or technology for storage of information such as computer-readable instructions, data structures, program modules, or data.

[0268] Computer storage media may include RAM, ROM, EPROM, EEPROM, flash memory (or other memory technologies), CD-ROM, digital versatile disks (DVD) (or other optical disk storage devices), magnetic cassettes, magnetic tapes, magnetic disk storage devices (or other magnetic storage devices), etc. Computer storage media need not include propagated data signals. Communication media may typically embody 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.

[0269] The term "modulated data signal" may mean a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. Communication media may include wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, radio frequency, infrared and other wireless media. Combinations of any of the above should also be included within the scope of computer-readable media.

[0270] The memory 934 may include computer storage media in the form of volatile and / or non-volatile memory. The memory 934 may be removable, non-removable, or a combination thereof. Example memory may include solid-state memory, hard drives, optical disk drives, and the like. As shown in FIG. 9, the memory 934 may store computer readable and / or computer executable programs 932 (e.g., software code or instruction sets) that, when executed, are configured to cause the processor 928 to perform various functions disclosed herein, for example, with respect to FIGS. 1-8. Alternatively, the programs 932 may not be directly executable by the processor 928, but may be configured (e.g., when compiled and executed) to cause the node 900 to perform various functions disclosed herein.

[0271] The processor 928 (e.g., having processing circuitry) may include an intelligent hardware device, e.g., a central processing unit (CPU), a microcontroller, an ASIC, etc. The processor 928 may include a memory. The processor 928 may process data 930 and programs 932 received from the memory 938, as well as information transmitted and received via the transceiver 920, the baseband communication module, and / or the network communication module. The processor 928 may also process information for transmission to the transceiver 920 for transmission to the network communication module via the antenna 936 for transmission to the CN.

[0272] One or more presentation components 938 can present the data indication to a person or another device. Examples of presentation components 938 can include a display device, a speaker, a printing component, a vibrating component, and the like.

[0273] In view of the present disclosure, it is apparent that various techniques may be used to implement the disclosed concepts without departing from the scope of those concepts. Moreover, although the concepts have been disclosed with specific reference to certain embodiments, those skilled in the art will recognize that changes may be made in form and detail without departing from the scope of those concepts. The disclosed embodiments are therefore considered in all respects to be illustrative and not restrictive. It should also be understood that the present disclosure is not limited to the particular embodiments disclosed. Moreover, many rearrangements, modifications, and substitutions are possible without departing from the scope of the present disclosure.

Claims

1. A method performed by a user equipment (UE (900)) for access control, comprising: While the UE is attempting to initiate a Small Data Transmission (SDT) procedure with a serving cell during the UE's Radio Resource Control (RRC) inactive state, receiving a radio resource configuration associated with the SDT procedure from the serving cell; and transmitting one or more uplink (UL) packets to the serving cell based on the radio resource configuration associated with the SDT procedure after performing a unified access control (UAC) mechanism; If an SDT attempt is not forbidden by the serving cell, the UE passes the UAC mechanism; and If the UE passes the UAC mechanism, the UE initiates a configured small data transmission (CG-SDT) procedure or a random access small data transmission (RA-SDT) procedure; determining whether to access at least one UL-CG for the SDT procedure based on a data volume threshold; and determining whether to initiate a Random Access (RA) procedure for the SDT procedure based on the data volume threshold; The SDT procedure includes accessing at least one UL configured grant (UL-CG) based on a UL-CG configuration preconfigured by the serving cell via UE-specific control signaling. A method comprising:

2. If the attempt of the SDT is forbidden by the serving cell, the UE does not pass the UAC mechanism; The method of claim 1, wherein if the UE does not pass the UAC mechanism, the UE inhibits the SDT procedure.

3. The method of claim 1, wherein if the UE passes the UAC mechanism, a Medium Access Control (MAC) entity of the UE initiates the CG-SDT procedure or the RA-SDT procedure.

4. The method of claim 1 , wherein the UAC mechanism is executed in an RRC entity of the UE.

5. The method of claim 1 , wherein the SDT procedure is a Random Access (RA) procedure triggered by the UE based on the radio resource configuration.

6. If the UE receives system information from the serving cell, the system information includes a cell barring bit indicating that the serving cell is barred; or If the serving cell is barred for a barring period determined by the UE based on the outcome of the UAC mechanism, The method of claim 1 , wherein the attempt of the SDT is prohibited.

7. The method of claim 6 , wherein the UAC mechanism is performed by the UE for the SDT procedure based on an access category associated with the SDT procedure.

8. determining the inhibit period for a previous access attempt with the serving cell; the previous access attempt occurs earlier than an access attempt of the UE to initiate the SDT procedure; The method of claim 6 , wherein the previous access attempt and the access attempt of the UE to initiate the SDT procedure belong to the same access category in the UAC mechanism.

9. 7. The method of claim 6, further comprising: not performing another UAC mechanism for the attempt of the SDT until the prohibition period has elapsed.

10. The method of claim 1 , further comprising receiving the data amount threshold via UE-specific RRC signaling or via broadcast system information.

11. 2. The method of claim 1, further comprising: determining an amount of pending UL data by considering only pending data in all of a plurality of logical channels allowed by the serving cell for the SDT during the RRC inactive state.

12. A user equipment (UE (900)) for access control, one or more non-transitory computer-readable media (934) having computer-executable instructions (932); and at least one processor (928) coupled to the one or more non-transitory computer readable media; The computer-executable instructions, when executed by the at least one processor, cause the UE to perform a method according to any one of claims 1 to 11.

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