WO2022236614A1

WO2022236614A1 - Method and apparatus for avoiding repeated state transition in small data transmission

Info

Publication number: WO2022236614A1
Application number: PCT/CN2021/092862
Authority: WO
Inventors: Ran YUE; Lianhai WU; Yuantao Zhang; Min Xu
Original assignee: Lenovo (Beijing) Limited
Priority date: 2021-05-10
Filing date: 2021-05-10
Publication date: 2022-11-17

Abstract

Methods and apparatuses for avoiding repeated state transition in small data transmission are disclosed. In one embodiment, a method at a user equipment (UE) that is in a non Radio Resource Control (RRC) _CONNECTED state with a network device comprises determining whether a criterion to provide the network device with an indication is met; and in response to the criterion being met, providing the network device with the indication implicitly or explicitly, wherein the indication is associated with the UE not initiating small data transmission (SDT) to the network device.

Description

METHOD AND APPARATUS FOR AVOIDING REPEATED STATE TRANSITION IN SMALL DATA TRANSMISSION

FIELD

The subject matter disclosed herein generally relates to wireless communications, and more particularly relates to method and apparatus for avoiding repeated state transition in small data transmission.

BACKGROUND

The following abbreviations are herewith defined, at least some of which are referred to within the following description: long term evolution (LTE) , New Radio (NR) , Very Large Scale Integration (VLSI) , Random Access Memory (RAM) , Read-Only Memory (ROM) , Erasable Programmable Read-Only Memory (EPROM or Flash Memory) , Compact Disc Read-Only Memory (CD-ROM) , Local Area Network (LAN) , Wide Area Network (WAN) , User Equipment (UE) , Evolved Node B (eNB) , Next Generation Node B (gNB) , Uplink (UL) , Downlink (DL) , Central Processing Unit (CPU) , Graphics Processing Unit (GPU) , Field Programmable Gate Array (FPGA) , Orthogonal Frequency Division Multiplexing (OFDM) , Radio Resource Control (RRC) , User Entity/Equipment (Mobile Terminal) , small data transmission (SDT) , Medium Access Control (MAC) , MAC control element (MAC CE) , radio access network (RAN) , timing advance (TA) , configured grant (CG) , normal UL (NUL) , supplementary UL (SUL) , Reference Signal Receiving Power (RSRP) , Reference Signal Receiving Quality (RSRQ) .

There are two RRC states for 4G LTE: RRC_IDLE and RRC_CONNECTED. 5G NR introduces a new RRC state, RRC_INACTIVE. Therefore, in 5G NR, RRC has three distinct states: RRC_IDLE, RRC_CONNECTED and RRC_INACTIVE. The behavior and functions of RRC are governed by the current state of RRC.

RRC_IDLE : Upon power on, UE enters into RRC_IDLE state. UE may move to this state from either RRC_CONNECTED mode or RRC_INACTIVE state.

RRC_INACTIVE: UE moves to this state from RRC_CONNECTED state. It is connected but inactive state of UE. In this state, UE maintains RRC connection and at the same time minimizes signaling and power consumption.

RRC_CONNECTED: UE remains in connection with the 5G-RAN/5GC in this state.

RRC states transition process is shown in Figure. 1.

RRC_IDLE to RRC_CONNECTED happens via the RRC Connection Setup procedure. This transition consists of three messages: RRCSetupRequest (UE initiated) , RRCSetup, and RRCSetupComplete.

RRC_CONNECTED to RRC_IDLE is via RRC Connection Release procedure with network-initiated RRCRelease message. Upper layers in the UE may also request a release. RRC connection is also released due to radio link failure, handover failure or cell not meeting cell selection criteria.

RRC_CONNECTED to RRC_INACTIVE is network initiated. It is entered via RRCRelease message with suspendConfig IE.

RRC_INACTIVE to RRC_CONNECTED can be triggered by the network via RAN paging. A paged UE will start with RRC Connection Resume procedure consisting of three messages: RRCResumeRequest, RRCResume (or RRCSetup) , RRCResumeComplete (or RRCSetupComplete) . This procedure can alternatively be initiated by UE for uplink transmission, including RNA update.

RRC_INACTIVE to RRC_IDLE happens when network responds to RRCResumeRequest with RRCRelease.

The main principle of the RRC_INACTIVE state is that the UE is able to resume to the RRC_CONNECTED state as quickly and efficiently as possible. When the UE transforms to RRC_INACTIVE state, both the UE and the RAN store all the information necessary to quickly resume to RRC_CONNECTED state. The message that transforms the UE to RRC_INACTIVE state contains a set of parameters used for RRC_INACTIVE state operation, such as a RAN Notification Area within which the UE is allowed to move without notifying the network. Further, it includes parameters used for secure transition back to the RRC_CONNECTED state, such as a UE identifier and security information needed to support encrypted resume messages.

An UE in RRC_INACTIVE state may initiate a resume procedure when there is a need to transmit data or signaling. In this case, the UE transmits an RRC resume request that includes the UE identifier and a security token to verify the legitimacy of the resume request. After the UE configuration is successfully retrieved, the target node resumes the stored configuration at the UE and applies any necessary modifications, such as the configuration of measurements and the addition or removal of bearers. The respective RRC resume message is integrity protected and encrypted using the security context stored in the network and the UE.

In the RRC_INACTIVE state, the UE is in a power-saving sleep state, but it still retains part of the RAN context (security context, UE capability information, etc. ) , and can be quickly awakened by a message to transfer from the RRC_INACTIVE state to the RRC_CONNECTED state.

NR Release 17 supports small data transmission (SDT) in RRC_INACTIVE state. That is to say, the UE in RRC_INACTIVE state can directly transmit small data without the need to transfer to the RRC_CONNECTED state.

A supplementary UL (SUL) carrier is introduced as a complement to the NUL carrier. The UE can select either SUL carrier or NUL carrier to perform SDT procedure. Switching between the NUL carrier and the SUL carrier means that the UL transmissions move from on one carrier (e.g. one of the NUL carrier and the SUL carrier) to on the other carrier (e.g. the other of the NUL carrier and the SUL carrier) .

The UE needs to receive SDT configuration to perform SDT procedure. There is no restriction on when or how frequently the UE can request for the SDT configuration. The CG-SDT resources (e.g. when CG-SDT is selected) can be maintained by the UE if the TA and other criteria are valid and the UE maintains in the cell.

When new SDT data arrives, the UE can select NUL carrier or SUL carrier. Afterwards, the UE may decide whether SDT or non-SDT (i.e. SDT is not possible) is selected. Both the selection of UL carriers and the selection of SDT or non-SDT are based on RSRP of the UE.

Figures 2, 3 and 4 illustrate different situations of the selection of UL carriers and the selection of SDT or non-SDT.

Figure 2 illustrates a situation in which both carriers (both SUL carrier and NUL carrier) are configured with SDT resources. It can be seen that when the RSRP of the UE is smaller than a threshold RSRP _{SDT/non-SDT_SUL}, non-SDT on SUL carrier is performed; when the RSRP of the UE is larger than the threshold RSRP _{SDT/non-SDT_SUL} and smaller than a threshold RSRP _{SDT_SUL/NUL}, SDT on SUL carrier is performed; when the RSRP of the UE is larger than the threshold RSRP _{SDT_SUL/NUL} and smaller than a threshold RSRP _{SDT/non-SDT_NUL}, non-SDT on NUL carrier is performed; and when the RSRP of the UE is larger than the threshold RSRP _SDT/non- _{SDT_NUL}, SDT on NUL carrier is performed. On the other hand, a legacy threshold RSRP _SUL/NUL is used for the legacy UE to select the carrier: when the RSRP of the UE is larger than the legacy threshold RSRP _SUL/NUL, NUL carrier is selected; and when the RSRP of the UE is smaller than the legacy threshold RSRP _SUL/NUL, SUL carrier is selected.

Figure 3 illustrates a situation in which only NUL carrier is configured with SDT resources (i.e. SUL carrier is not configured with SDT resources) . It can be seen that when the RSRP of the UE is smaller than a threshold RSRP _{SDT _SUL/NUL}, non-SDT on SUL carrier is performed; when the RSRP of the UE is larger than the threshold RSRP _{SDT _SUL/NUL} and smaller than a threshold RSRP _{SDT/non-SDT_NUL}, non-SDT on NUL carrier is performed; and when the RSRP of the UE is larger than the threshold RSRP _{SDT/non-SDT_NUL}, SDT on NUL carrier is performed. On the other hand, a legacy threshold RSRP _SUL/NUL is used for the legacy UE to select the carrier: when the RSRP of the UE is larger than the legacy threshold RSRP _SUL/NUL, NUL carrier is selected; and when the RSRP of the UE is smaller than the legacy threshold RSRP _SUL/NUL, SUL carrier is selected.

Figure 4 illustrates a situation in which only SUL carrier is configured with SDT resources (i.e. NUL carrier is not configured with SDT resources) . It can be seen that when the RSRP of the UE is smaller than a threshold RSRP _{SDT/non-SDT_SUL}, non-SDT on SUL carrier is performed; when the RSRP of the UE is larger than the threshold RSRP _{SDT/non-SDT_SUL} and smaller than a threshold RSRP _{SDT _SUL/NUL}, SDT on SUL carrier is performed; when the RSRP of the UE is larger than the threshold RSRP _{SDT _SUL/NUL}, non-SDT on NUL carrier is performed. On the other hand, a threshold RSRP _SUL/NUL is used for the legacy UE to to select SUL carrier: when the RSRP of the UE is larger than the threshold RSRP _SUL/NUL, NUL carrier is selected; and when the RSRP of the UE is smaller than the threshold RSRP _SUL/NUL, SUL carrier is selected.

It can be seen that the legacy threshold RSRP _SUL/NUL may be different from any of the SDT RSRP thresholds (e.g. the threshold RSRP _{SDT/non-SDT_SUL}, the threshold RSRP _SDT _{_SUL/NUL}, and the threshold RSRP _{SDT/non-SDT_NUL}) .

As shown in Figure 2 and Figure 4, the UE which selects the NUL carrier cannot initiate a SDT on NUL carrier because the RSRP is lower than the threshold RSRP _{SDT _SUL/NUL} for performing SDT on NUL carrier. The UE performs non-SDT on NUL carrier and initiates a RRC resume procedure (to resume to RRC_CONNECTED state) to transmit data. Afterwards, the network device (e.g. gNB) could release the UE to RRC_INACTIVE state based on the existing principle, e.g. the traffic characteristic, while the network device may not identify that the UE resumes to RRC_CONNECTED state because of lower RSRP (i.e. the measured RSRP is lower than the threshold RSRP _{SDT _SUL/NUL} for performing SDT on NUL carrier) . If the RSRP of the UE doesn’t change distinctly, the procedure of resuming and releasing to RRC_INACTIVE state will be repeated. It is obvious not expected.

In addition, as shown in Figure 3, the UE which selects SUL carrier cannot perform SDT on the SUL carrier because the SUL carrier is not configured with SDT resources.

This invention targets resolving the above-described problems, e.g., avoiding repeated state transition in small data transmission.

BRIEF SUMMARY

Methods and apparatuses for avoiding repeated state transition in small data transmission are disclosed.

In one embodiment, a method at a user equipment (UE) that is in a non Radio Resource Control (RRC) _CONNECTED state with a network device comprises determining whether a criterion to provide the network device with an indication is met; and in response to the criterion being met, providing the network device with the indication implicitly or explicitly, wherein the indication is associated with the UE not initiating small data transmission (SDT) to the network device.

In one embodiment, the criterion may be any of: the repeated times of state transition between the resuming and releasing to non RRC_CONNECTED state are larger than a first predetermined value; the repeated times of state transition between the resuming and releasing to non RRC_CONNECTED state are larger than a second predetermined value within a configured time period; and the measured RSRP or RSRQ is lower than a third predetermined value.

In another embodiment, the providing the network device with the indication explicitly comprises: transmitting the indication to the network device, the indication indicates that the reason for not initiating SDT is the measured RSRP being lower than SDT RSRP threshold, or the measured RSRP is not suitable for initiating SDT. The indication may be carried by a resume cause in a resume request to RRC_CONNECTED state, or a MAC CE, or a message, or UCI. The providing the network device with the indication implicitly comprises: forbidding the UE to request for SDT configuration or CG-SDT configuration for a time period.

In some embodiment, the method may further comprise selecting UL carrier based on legacy selection rule.

In some embodiment, a method at a UE that is in a non Radio Resource Control (RRC) _CONNECTED state with a network device comprises receiving an SDT configuration for SDT transmission from the network device; and transmitting, to the network device, a reject message and/or a waittime message to reject the SDT configuration received from the network device. When any of the following criteria is met, the reject message and/or the waittime message are transmitted: the measured RSRP (or RSRQ) is smaller than the RSRP (or RSRQ) threshold for SDT; the measured RSRP (or RSRQ) is smaller than the RSRP (or RSRQ) threshold for SDT minus a delta value, where the delta value is not less than 0; the repeated times of state transition between the resuming and releasing to non RRC_CONNECTED state are larger than a first predetermined value; the repeated times of state transition between the resuming and releasing to non RRC_CONNECTED state are larger than a second predetermined value within a configured period; and the measured RSRP has decreased more than a changing threshold. The reject message means that the measured RSRP falls within non-SDT selection range or the measured RSRP is not suitable for SDT. The waittime message indicates a time period after which the UE releases to non RRC_CONNECTED state, or a time period after which the UE is expected to be configured with SDT configuration.

In some embodiment, a method at a UE comprises receiving SDT specific RSRP thresholds from a network device, wherein the SDT specific RSRP thresholds include a RSRP threshold for selection of SDT or non-SDT on SUL carrier, a RSRP threshold for SDT to select SUL carrier or NUL carrier, and a RSRP threshold for selection of SDT or non-SDT on NUL carrier, and the RSRP threshold for SDT to select SUL carrier or NUL carrier is larger than or has the same value as the RSRP threshold for selection of SDT or non-SDT on NUL carrier.

In some embodiment, a method at a network device, where a user equipment (UE) is in a non Radio Resource Control (RRC) _CONNECTED with the network device, comprises transmitting an SDT configuration to the UE; and receiving, from the UE, a reject message and/or a waittime message to reject the SDT configuration. The reject message means that the measured RSRP falls within non-SDT selection range or the measured RSRP is not suitable for SDT. The waittime message indicates a time period after which the UE releases to non RRC_CONNECTED state, or a time period after which the UE is expected to be configured with SDT configuration. The method may further comprise transmitting an SDT configuration to the UE after the waittime, or after the UE reports a higher RSRP, or after the UE requests for the SDT configuration.

In some embodiment, a method at a network device comprises transmitting SDT specific RSRP thresholds to a user equipment (UE) , wherein the SDT specific RSRP thresholds include a RSRP threshold for determination of SDT or non-SDT on SUL carrier, a RSRP threshold for SDT to select SUL carrier or NUL carrier, and a RSRP threshold for determination of SDT or non-SDT on NUL carrier, and the RSRP threshold for SDT to select SUL carrier or NUL carrier is larger than or has the same value as the RSRP threshold for selection of SDT or non-SDT on NUL carrier.

In some embodiment, a user equipment (UE) comprises a transceiver; a memory; and a processor coupled to the transceiver and the memory and configured to: determine whether a criterion to provide a network device with an indication is met; and in response to the criterion being met, provide the network device with the indication implicitly or explicitly, wherein, the indication is associated with the UE not initiating small data transmission (SDT) to the network device, and the UE is in a non Radio Resource Control (RRC) _CONNECTED state with the network device.

In some embodiment, a user equipment (UE) comprises a transceiver; a memory; and a processor coupled to the transceiver and the memory and configured to: configure the transceiver to receive an SDT configuration from a network device; and configure the transceiver to transmit, to the network device, a reject message and/or a waittime message to reject the SDT configuration, wherein, the UE is in a non Radio Resource Control (RRC) _CONNECTED state with the network device.

In some embodiment, a user equipment (UE) comprises a transceiver; a memory; and a processor coupled to the transceiver and the memory and configured to: configure the transceiver to receive SDT specific RSRP thresholds to a user equipment (UE) , wherein the SDT specific RSRP thresholds include a RSRP threshold for determination of SDT or non-SDT on SUL carrier, a RSRP threshold for SDT to select SUL carrier or NUL carrier, and a RSRP threshold for determination of SDT or non-SDT on NUL carrier, and the RSRP threshold for SDT to select SUL carrier or NUL carrier is larger than or has the same value as the RSRP threshold for selection of SDT or non-SDT on NUL carrier.

In some embodiment, a network device, where a user equipment (UE) is in a non Radio Resource Control (RRC) _CONNECTED with the network device, comprises a transceiver; a memory; and a processor coupled to the transceiver and the memory and configured to: configure the transceiver to transmit an SDT configuration to the UE; and configure the transceiver to receive, from the UE, a reject message and/or a waittime message to reject the SDT configuration.

In another embodiment, a network device comprises a transceiver; a memory; and a processor coupled to the transceiver and the memory and configured to: configure the transceiver to transmit SDT specific RSRP thresholds to a user equipment (UE) , wherein the SDT specific RSRP thresholds include a RSRP threshold for determination of SDT or non-SDT on SUL carrier, a RSRP threshold for SDT to select SUL carrier or NUL carrier, and a RSRP threshold for determination of SDT or non-SDT on NUL carrier, and the RSRP threshold for SDT to select SUL carrier or NUL carrier is larger than or has the same value as the RSRP threshold for selection of SDT or non-SDT on NUL carrier.

BRIEF DESCRIPTION OF THE DRAWINGS

A more particular description of the embodiments briefly described above will be rendered by reference to specific embodiments that are illustrated in the appended drawings. Understanding that these drawings depict only some embodiments, and are not therefore to be considered to be limiting of scope, the embodiments will be described and explained with additional specificity and detail through the use of the accompanying drawings, in which:

Figure 1 illustrates RRC states in NR;

Figure 2 illustrates a situation in which both SUL carrier and NUL carrier are configured with SDT resources;

Figure 3 illustrates a situation in which only NUL carrier is configured with SDT resources;

Figure 4 illustrates a situation in which only SUL carrier is configured with SDT resources;

Figure 5 illustrates an example of the third embodiment;

Figure 6 is a schematic flow chart diagram illustrating an embodiment of a method;

Figure 7 is a schematic flow chart diagram illustrating an embodiment of a method;

Figure 8 is a schematic flow chart diagram illustrating an embodiment of a method;

Figure 9 is a schematic flow chart diagram illustrating an embodiment of a method;

Figure 10 is a schematic flow chart diagram illustrating an embodiment of a method; and

Figure 11 is a schematic block diagram illustrating apparatuses according to one embodiment.

DETAILED DESCRIPTION

As will be appreciated by one skilled in the art that certain aspects of the embodiments may be embodied as a system, apparatus, method, or program product. Accordingly, embodiments may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc. ) or an embodiment combining software and hardware aspects that may generally all be referred to herein as a “circuit” , “module” or “system” . Furthermore, embodiments may take the form of a program product embodied in one or more computer readable storage devices storing machine-readable code, computer readable code, and/or program code, referred to hereafter as “code” . The storage devices may be tangible, non-transitory, and/or non-transmission. The storage devices may not embody signals. In a certain embodiment, the storage devices only employ signals for accessing code.

Certain functional units described in this specification may be labeled as “modules” , in order to more particularly emphasize their independent implementation. For example, a module may be implemented as a hardware circuit comprising custom very-large-scale integration (VLSI) circuits or gate arrays, off-the-shelf semiconductors such as logic chips, transistors, or other discrete components. A module may also be implemented in programmable hardware devices such as field programmable gate arrays, programmable array logic, programmable logic devices or the like.

Modules may also be implemented in code and/or software for execution by various types of processors. An identified module of code may, for instance, include one or more physical or logical blocks of executable code which may, for instance, be organized as an object, procedure, or function. Nevertheless, the executables of an identified module need not be physically located together, but, may include disparate instructions stored in different locations which, when joined logically together, include the module and achieve the stated purpose for the module.

Indeed, a module of code may contain a single instruction, or many instructions, and may even be distributed over several different code segments, among different programs, and across several memory devices. Similarly, operational data may be identified and illustrated herein within modules and may be embodied in any suitable form and organized within any suitable type of data structure. This operational data may be collected as a single data set, or may be distributed over different locations including over different computer readable storage devices. Where a module or portions of a module are implemented in software, the software portions are stored on one or more computer readable storage devices.

Any combination of one or more computer readable medium may be utilized. The computer readable medium may be a computer readable storage medium. The computer readable storage medium may be a storage device storing code. The storage device may be, for example, but need not necessarily be, an electronic, magnetic, optical, electromagnetic, infrared, holographic, micromechanical, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing.

A non-exhaustive list of more specific examples of the storage device would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, random access memory (RAM) , read-only memory (ROM) , erasable programmable read-only memory (EPROM or Flash Memory) , portable compact disc read-only memory (CD-ROM) , an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer-readable storage medium may be any tangible medium that can contain or store a program for use by or in connection with an instruction execution system, apparatus, or device.

Code for carrying out operations for embodiments may include any number of lines and may be written in any combination of one or more programming languages including an object-oriented programming language such as Python, Ruby, Java, Smalltalk, C++, or the like, and conventional procedural programming languages, such as the "C" programming language, or the like, and/or machine languages such as assembly languages. The code may be executed entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the very last scenario, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN) , or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider) .

Reference throughout this specification to “one embodiment” , “an embodiment” , or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in one embodiment” , “in an embodiment” , and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment, but mean “one or more but not all embodiments” unless expressly specified otherwise. The terms “including” , “comprising” , “having” , and variations thereof mean “including but are not limited to” , unless otherwise expressly specified. An enumerated listing of items does not imply that any or all of the items are mutually exclusive, otherwise unless expressly specified. The terms “a” , “an” , and “the” also refer to “one or more” unless otherwise expressly specified.

Furthermore, described features, structures, or characteristics of various embodiments may be combined in any suitable manner. In the following description, numerous specific details are provided, such as examples of programming, software modules, user selections, network transactions, database queries, database structures, hardware modules, hardware circuits, hardware chips, etc., to provide a thorough understanding of embodiments. One skilled in the relevant art will recognize, however, that embodiments may be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid any obscuring of aspects of an embodiment.

Aspects of different embodiments are described below with reference to schematic flowchart diagrams and/or schematic block diagrams of methods, apparatuses, systems, and program products according to embodiments. It will be understood that each block of the schematic flowchart diagrams and/or schematic block diagrams, and combinations of blocks in the schematic flowchart diagrams and/or schematic block diagrams, can be implemented by code. This code may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which are executed via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the schematic flowchart diagrams and/or schematic block diagrams for the block or blocks.

The code may also be stored in a storage device that can direct a computer, other programmable data processing apparatus, or other devices, to function in a particular manner, such that the instructions stored in the storage device produce an article of manufacture including instructions which implement the function specified in the schematic flowchart diagrams and/or schematic block diagrams block or blocks.

The code may also be loaded onto a computer, other programmable data processing apparatus, or other devices, to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the code executed on the computer or other programmable apparatus provides processes for implementing the functions specified in the flowchart and/or block diagram block or blocks.

The schematic flowchart diagrams and/or schematic block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of apparatuses, systems, methods and program products according to various embodiments. In this regard, each block in the schematic flowchart diagrams and/or schematic block diagrams may represent a module, segment, or portion of code, which includes one or more executable instructions of the code for implementing the specified logical function (s) .

It should also be noted that in some alternative implementations, the functions noted in the block may occur out of the order noted in the Figures. For example, two blocks shown in succession may substantially be executed concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. Other steps and methods may be conceived that are equivalent in function, logic, or effect to one or more blocks, or portions thereof, to the illustrated Figures.

Although various arrow types and line types may be employed in the flowchart and/or block diagrams, they are understood not to limit the scope of the corresponding embodiments. Indeed, some arrows or other connectors may be used to indicate only the logical flow of the depicted embodiment. For instance, an arrow may indicate a waiting or monitoring period of unspecified duration between enumerated steps of the depicted embodiment. It will also be noted that each block of the block diagrams and/or flowchart diagrams, and combinations of blocks in the block diagrams and/or flowchart diagrams, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and code.

The description of elements in each Figure may refer to elements of proceeding figures. Like numbers refer to like elements in all figures, including alternate embodiments of like elements.

Reference will now be made in detail to some embodiments of the present application, examples of which are illustrated in the accompanying drawings. To facilitate understanding, embodiments are provided under specific network architecture and new service scenarios, such as 3GPP 5G, 3GPP LTE, 3GPP NR-U, NR Radio Access operating with shared spectrum channel access and so on. It is contemplated that along with the developments of network architectures and new service scenarios, all embodiments in the present application are also applicable to similar technical problems. Moreover, the terminologies recited in the present application may change, which should not affect the principle of the present application. Embodiments of the present disclosure can also be applied to unlicensed spectrum scenario.

According to a first embodiment, the UE may inform the network device that the reason for not initiating SDT is because the RSRP of the UE is lower than SDT RSRP threshold (e.g. more precisely, the RSRP of the UE falls within non SDT selection range) or the measured RSRP is not suitable for SDT. With reference to Figure 2, the UE does not initiate SDT on SUL carrier when the RSRP is lower than the threshold RSRP _{SDT/non-SDT_SUL}. When the RSRP is lower than the threshold RSRP _{SDT/non-SDT_SUL}, the RSRP is in non SDT selection range for SUL carrier. Moreover, the UE does not initiate SDT on NUL carrier when the RSRP is lower than the threshold RSRP _{SDT/non-SDT_NUL}. More precisely, when the RSRP is lower than the threshold RSRP _{SDT/non-SDT_NUL} and larger than the threshold RSRP _{SDT _SUL/NUL} (i.e. falls within non SDT selection range for NUL carrier) , the UE does not initiate SDT on NUL carrier.

The UE is configured to allow SDT. For example, the SUL carrier and/or the NUL carrier are configured with SDT resources (see the situations in Figures 2 to 4) . The UE is in RRC_INACTIVE state. For example, the UE is released to the RRC_INACTIVE state. The UE performs UL carrier selection based on SDT specific RSRP thresholds, such as the threshold RSRP _{SDT/non-SDT_SUL}, the threshold RSRP _{SDT _SUL/NUL}, and the threshold RSRP _{SDT/non-SDT_NUL} shown in Figures 2-4. After the UE compares the measured RSRP (i.e. the RSRP of the UE) with the SDT specific RSRP thresholds, the UE determines to perform non-SDT (either non-SDT on SUL carrier or non-SDT on NUL carrier) .

The UE determines whether to transmit an indication to the network device based on any of the following criteria:

Criterion 1: the repeated times of state transition between the resuming and releasing to RRC_INACTIVE state are larger than a first predetermined value. For example, it is one time if the UE is released to RRC__INACTIVE state, then resuming to RRC_CONNECTED state. Alternatively, it is one time if the UE is resumed to RRC_CONNECTED state, then released to RRC_INACTIVE state.

Criterion 2: the repeated times of state transition between the resuming and releasing to RRC_INACTIVE state are larger than a second predetermined value within a configured time period (or within a time duration, or within a time window) . For example, it is one time if the UE is released to RRC_INACTIVE state, then resuming to RRC_CONNECTED state within a configured time period. Alternatively it is one time if the UE is resumed to RRC_CONNECTED state, then released to RRC_INACTIVE state within a configured time period.

Criterion 3: the measured RSRP (or RSRQ) falls within non-SDT selection range (e.g. the measured RSRP makes the UE determine to perform non-SDT on SUL carrier or non-SDT on NUL carrier) .

If any of the above criteria is met, the UE transmits an indication to the network device. Any of the above criteria can be configured or pre-defined to the UE. The indication may indicate that the reason for not initiating SDT is that the measured RSRP (or RSRQ) is lower than SDT RSRP (or RSRQ) threshold (or the RSRP (or RSRQ) of the UE falls within non SDT selection range) , or that the measured RSRP (or RSRQ) is not suitable for initiating SDT.

The indication may be carried by a resume cause in the resume request by the UE to the network device to resume the UE to RRC_CONNECTED state. In this condition, the indication is transmitted from the UE that is still in RRC_INACTIVE state.

Alternatively, the indication may be transmitted from the UE to the network device after the UE has changed (e.g. resumed) to RRC_CONNECTED state. For example, the indication may be carried in a MAC CE or a message or UCI.

In the first embodiment, the indication that the reason for not initiating SDT is that the measured RSRP (or RSRQ) is lower than SDT RSRP (or RSRQ) threshold (or falls within non SDT selection range) , or that the measured RSRP (or RSRQ) is not suitable for initiating SDT is transmitted to the network device explicitly.

Upon receiving the indication, the network device may maintain the UE in RRC_CONNECTED state, or release the UE to RRC_INACTIVE state for SDT later.

According to a variety of the first embodiment, the indication can be implicitly informed to the network device. In particular, when the UE determines to perform non-SDT (either non-SDT on SUL carrier or non-SDT on NUL carrier) , the UE may be forbidden to request for SDT configuration or CG based SDT (CG-SDT) configuration for a time period (or time duration) . In other words, when the network device does not receive the request for SDT configuration or CG-SDT configuration, the network device understands that the reason for the UE not initiating SDT is that the measured RSRP (or RSRQ) of the UE is lower than SDT RSRP (or RSRQ) threshold (or falls within non-SDT selection range) , or the measured RSRP (or RSRQ) is not suitable for initiating SDT.

The time period (or time duration) can be controlled by a timer (e.g. a timer configured by the network device) , or a time window (e.g. a time window configured by the network device) , or a RSRP changing threshold (i.e. the measured RSRP has increased more than a changing threshold) , or the measured RSRP falling within SDT selection range (e.g. the measured RSRP is larger than RSRP _{SDT/non-SDT_NUL}, or the measured RSRP is larger than RSRP _{SDT/non-SDT_SUL} and smaller than RSRP _{SDT _SUL/NUL}) .

According to a further variety of the first embodiment, a further step of reselecting UL carrier can be added. After the UE decides not to perform SDT because the measured RSRP (or RSRQ) of the UE is lower than SDT RSRP (or RSRQ) threshold (or falls within non-SDT selection range) , or the measured RSRP (or RSRQ) is not suitable for initiating SDT, the UE may further reselect the UL carrier based on legacy selection rule, i.e. based on the comparison of the measured RSRP with the threshold RSRP _SUL/NUL. For example, with reference to Figure 3, if the measured RSRP is larger than the threshold RSRP _SUL/NUL and smaller than the threshold RSRP _{SDT _SUL/NUL}, the SUL carrier is selected according to the comparison with the SDT specific RSRP thresholds (e.g. with the threshold RSRP _{SDT _SUL/NUL}) . On the other hand, if the measured RSRP is compared with legacy RSRP threshold (e.g. the threshold RSRP _SUL/NUL) , the NUL carrier can be selected. The network device may configure the UE on whether the further step is performed or not.

According to a second embodiment, the UE may reject SDT configuration configured by the network device.

The UE measures its RSRP (or RSRQ) .

The network device configures the UE with SDT configuration.

When the UE receives the SDT configuration, if any of the following criteria is met, the UE may reject the SDT configuration and/or recommend a waittime to the network device. The network device may have sent a configuration to the UE to allow the UE to reject the SDT configuration.

Criterion 1: the measured RSRP (or RSRQ) is smaller than the RSRP (or RSRQ) threshold for SDT (or falls within non-SDT selection range) .

Criterion 2: the measured RSRP (or RSRQ) is smaller than the RSRP (or RSRQ) threshold for SDT minus a delta value (or falls within non-SDT selection range minus a delta value) , where the delta value is not less than 0. If the non-SDT selection range is from A to B, the “non-SDT selection range minus a delta value” means from A -delta value to B -delta value.

Criterion 3: the repeated times of state transition between the resuming and releasing to RRC_INACTIVE state are larger than a first predetermined value.

Criterion 4: the repeated times of state transition between the resuming and releasing to RRC_INACTIVE state are larger than a second predetermined value within a configured period (or within a time duration, or within a time window) .

Criterion 5: the measured RSRP has decreased more than a changing threshold.

The rejection to the SDT configuration may be performed by transmitting a reject message to the network device. For example, the reject message can be carried by a resume cause in the resume request by the UE to the network device to resume to the RRC_CONNECTED state. The reject message means that the measured RSRP falls within non-SDT selection range or the measured RSRP is not suitable for SDT.

In addition to the reject message or alternative to the reject message, the UE may transmit a waittime to the network device. The waittime refers to a time period recommended by the UE. The waittime may mean that, when the network device releases the UE to RRC_INACTIVE state, the UE will wait for the time period of waittime to release to RRC_INACTIVE state (i.e. the UE would apply the SDT configuration after the time period of waittime) . Alternatively, the waittime may mean that the UE is expected to be released to RRC_INACTIVE state after the time period of waittime (i.e. the UE is expected to be configured with SDT configuration after the waittime) .

If the network device receives the waittime, the network device configures the UE with SDT configuration (i.e. release the UE to RRC_INACTIVE state) after the waittime or after the UE reports a higher RSRP (e.g. the higher RSRP is higher than SDT RSRP threshold or falls within SDT selection range) or after the UE requests for the SDT configuration again.

The waittime may be carried by a resume cause in the resume request by the UE to the network device to resume to the RRC_CONNECTED state.

According to a third embodiment, the configuration of the SDT specific RSRP thresholds by the network device is restricted. In particular, as shown in Figure 5, the RSRP threshold for SDT to select SUL carrier or NUL carrier (e.g. the threshold RSRP _{SDT _SUL/NUL}) is configured as the RSRP threshold for the selection of SDT or non-SDT on NUL (e.g. the threshold RSRP _{SDT/non-SDT_NUL}) . A comparison between Figure 2 and Figure 5 indicates that the threshold RSRP _{SDT _SUL/NUL} is moved to the same position as the threshold RSRP _{SDT/non-SDT_NUL}, that is, reconfigured as the same value as the threshold RSRP _{SDT/non-SDT_NUL}. Alternatively, the RSRP threshold for SDT to select SUL carrier or NUL carrier (e.g. RSRP _{SDT _SUL/NUL}) can be configured to be larger than the RSRP threshold for selection of SDT or non-SDT on NUL carrier (e.g. RSRP _{SDT/non-SDT_NUL}) .

With the configured or reconfigured threshold RSRP _{SDT _SUL/NUL} (which is the same as the threshold RSRP _{SDT/non-SDT_NUL}) , the UE would only select non-STD on SUL carrier, SDT on SUL carrier or SDT on NUL carrier. In other words, non-SDT on NUL carrier is impossible to be selected because the threshold RSRP _{SDT _SUL/NUL} has the same value as the threshold RSRP _{SDT/non-SDT_NUL}.

If the SDT specific RSRP thresholds are configured as illustrated in Figure 1, only when the RSRP of the UE is larger than the threshold RSRP _{SDT/non-SDT_SUL} and smaller than the threshold RSRP _{SDT _SUL/NUL}, SDT on SUL carrier is selected; while if the RSRP of the UE is larger than the threshold RSRP _{SDT _SUL/NUL} and smaller than the threshold RSRP _{SDT/non-SDT_NUL}, non-SDT on NUL carrier is selected.

On the other hand, if the SDT specific RSRP thresholds are configured as illustrated in Figure 5, because the threshold RSRP _{SDT _SUL/NUL} is configured or reconfigured as the same value as or a higher value than the threshold RSRP _{SDT/non-SDT_NUL}, when the RSRP of the UE is larger than the threshold RSRP _{SDT/non-SDT_SUL} and smaller than the reconfigured threshold RSRP _{SDT _SUL/NUL}, SDT on SUL carrier is selected. In other words, if the SDT specific RSRP thresholds are configured as illustrated in Figure 5, the non-SDT on NUL carrier is impossible to be selected.

In the above embodiment, the UE performs SDT procedure in RRC_INACTIVE state. The present disclosure is not limited to the UE in RRC_INACTIVE state. It is possible that the UE in RRC_IDLE state so long as the UE can perform SDT procedure in RRC_IDLE state. The RRC_INACTIVE state and the RRC_IDLE state can be commonly referred to as non-connected state (e.g. non RRC_CONNECTED state) .

Figure 6 is a schematic flow chart diagram illustrating an embodiment of a method 600 according to the present application. In some embodiments, the method 600 is performed by an apparatus, such as a remote unit (e.g. UE) . In certain embodiments, the method 600 may be performed by a processor executing program code, for example, a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or the like. The UE is in a non Radio Resource Control (RRC) _CONNECTED state with a network device.

The method 600 may include 602 determining whether a criterion to provide the network device with an indication is met; and 604 in response to the criterion being met, providing the network device with the indication implicitly or explicitly, wherein the indication is associated with the UE not initiating small data transmission (SDT) to the network device.

The criterion may be any of: the repeated times of state transition between the resuming and releasing to non RRC_CONNECTED state are larger than a first predetermined value; the repeated times of state transition between the resuming and releasing to non RRC_CONNECTED state are larger than a second predetermined value within a configured time period; and the measured RSRP or RSRQ is lower than a third predetermined value.

The providing the network device with the indication explicitly comprises: transmitting the indication to the network device, the indication indicates that the reason for not initiating SDT is the measured RSRP being lower than SDT RSRP threshold, or the measured RSRP is not suitable for initiating SDT. The indication may be carried by a resume cause in a resume request to RRC_CONNECTED state, or a MAC CE, or a message, or UCI.

The providing the network device with the indication implicitly comprises: forbidding the UE to request for SDT configuration or CG-SDT configuration for a time period.

The method may further comprise selecting UL carrier based on legacy selection rule.

Figure 7 is a schematic flow chart diagram illustrating an embodiment of a method 700 according to the present application. In some embodiments, the method 700 is performed by an apparatus, such as a remote unit (e.g. UE) . In certain embodiments, the method 700 may be performed by a processor executing program code, for example, a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or the like. The UE is in a non Radio Resource Control (RRC) _CONNECTED state with a network device.

The method 700 may include 702 receiving an SDT configuration from the network device; and 704 transmitting, to the network device, a reject message and/or a waittime message to reject the SDT configuration received from the network device.

When any of the following criteria is met, the reject message and/or the waittime message are transmitted: the measured RSRP (or RSRQ) is smaller than the RSRP (or RSRQ) threshold for SDT; the measured RSRP (or RSRQ) is smaller than the RSRP (or RSRQ) threshold for SDT minus a delta value, where the delta value is not less than 0; the repeated times of state transition between the resuming and releasing to non RRC_CONNECTED state are larger than a first predetermined value; the repeated times of state transition between the resuming and releasing to non RRC_CONNECTED state are larger than a second predetermined value within a configured period; and the measured RSRP has decreased more than a changing threshold.

The reject message means that the measured RSRP falls within non-SDT selection range or the measured RSRP is not suitable for SDT. The waittime message indicates a time period after which the UE releases to non RRC_CONNECTED state, or a time period after which the UE is expected to be configured with SDT configuration.

Figure 8 is a schematic flow chart diagram illustrating a further embodiment of a method 800 according to the present application. In some embodiments, the method 800 is performed by an apparatus, such as a base unit or a network device. In certain embodiments, the method 800 may be performed by a processor executing program code, for example, a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or the like. A user equipment (UE) is in a non Radio Resource Control (RRC) _CONNECTED with the network device.

The method 800 may include 802 transmitting an SDT configuration to the UE; and 804 receiving, from the UE, a reject message and/or a waittime message to reject the SDT configuration.

The method may further comprise transmitting an SDT configuration to the UE after the time period indicated by the waittime message, or after the UE reports a higher RSRP, or after the UE requests for the SDT configuration.

Figure 9 is a schematic flow chart diagram illustrating a further embodiment of a method 900 according to the present application. In some embodiments, the method 900 is performed by an apparatus, such as a base unit or a network device. In certain embodiments, the method 900 may be performed by a processor executing program code, for example, a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or the like.

The method 900 may include 902 transmitting SDT specific RSRP thresholds to a user equipment (UE) , wherein the SDT specific RSRP thresholds include a RSRP threshold for determination of SDT or non-SDT on SUL carrier, a RSRP threshold for SDT to select SUL carrier or NUL carrier, and a RSRP threshold for determination of SDT or non-SDT on NUL carrier, and the RSRP threshold for SDT to select SUL carrier or NUL carrier is larger than or has the same value as the RSRP threshold for selection of SDT or non-SDT on NUL carrier.

Figure 10 is a schematic flow chart diagram illustrating an embodiment of a method 1000 according to the present application. In some embodiments, the method 1000 is performed by an apparatus, such as a remote unit (e.g. UE) . In certain embodiments, the method 1000 may be performed by a processor executing program code, for example, a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or the like.

The method 1000 may include 1002 receiving SDT specific RSRP thresholds from a network device, wherein the SDT specific RSRP thresholds include a RSRP threshold for selection of SDT or non-SDT on SUL carrier, a RSRP threshold for SDT to select SUL carrier or NUL carrier, and a RSRP threshold for selection of SDT or non-SDT on NUL carrier, and the RSRP threshold for SDT to select SUL carrier or NUL carrier is larger than or has the same value as the RSRP threshold for selection of SDT or non-SDT on NUL carrier.

Figure 11 is a schematic block diagram illustrating apparatuses according to one embodiment. Referring to Figure 11, the UE (i.e. the remote unit) includes a processor, a memory, and a transceiver. The processor implements a function, a process, and/or a method which are proposed in Figure 6 or 7 or 10.

The user equipment (UE) comprises a transceiver; a memory; and a processor coupled to the transceiver and the memory and configured to: determine whether a criterion to provide a network device with an indication is met; and in response to the criterion being met, provide the network device with the indication implicitly or explicitly, wherein, the indication is associated with the UE not initiating small data transmission (SDT) to the network device, and the UE is in a non Radio Resource Control (RRC) _CONNECTED state with the network device.

Alternatively, the user equipment (UE) comprises a transceiver; a memory; and a processor coupled to the transceiver and the memory and configured to: configure the transceiver to receive an SDT configuration for SDT transmission from a network device; and configure the transceiver to transmit, to the network device, a reject message and/or a waittime message to reject the SDT configuration, wherein, the UE is in a non Radio Resource Control (RRC) _CONNECTED state with the network device.

Further alternatively, the user equipment (UE) comprises a transceiver; a memory; and a processor coupled to the transceiver and the memory and configured to: configure the transceiver to receive SDT specific RSRP thresholds to a user equipment (UE) , wherein the SDT specific RSRP thresholds include a RSRP threshold for determination of SDT or non-SDT on SUL carrier, a RSRP threshold for SDT to select SUL carrier or NUL carrier, and a RSRP threshold for determination of SDT or non-SDT on NUL carrier, and the RSRP threshold for SDT to select SUL carrier or NUL carrier is larger than or has the same value as the RSRP threshold for selection of SDT or non-SDT on NUL carrier.

Referring to Figure 11, the gNB (i.e. base unit or network device) includes a processor, a memory, and a transceiver. The processors implement a function, a process, and/or a method which are proposed in Figure 8 or 9.

A user equipment (UE) is in a non Radio Resource Control (RRC) _CONNECTED with the network device. The network device comprises a transceiver; a memory; and a processor coupled to the transceiver and the memory and configured to: configure the transceiver to transmit an SDT configuration for SDT transmission to the UE; and configure the transceiver to receive, from the UE, a reject message and/or a waittime message to reject the SDT configuration.

Alternatively, the network device comprises a transceiver; a memory; and a processor coupled to the transceiver and the memory and configured to: configure the transceiver to transmit SDT specific RSRP thresholds to a user equipment (UE) , wherein the SDT specific RSRP thresholds include a RSRP threshold for determination of SDT or non-SDT on SUL carrier, a RSRP threshold for SDT to select SUL carrier or NUL carrier, and a RSRP threshold for determination of SDT or non-SDT on NUL carrier, and the RSRP threshold for SDT to select SUL carrier or NUL carrier is larger than or has the same value as the RSRP threshold for selection of SDT or non-SDT on NUL carrier.

Layers of a radio interface protocol may be implemented by the processors. The memories are connected with the processors to store various pieces of information for driving the processors. The transceivers are connected with the processors to transmit and/or receive a radio signal. Needless to say, the transceiver may be implemented as a transmitter to transmit the radio signal and a receiver to receive the radio signal.

The memories may be positioned inside or outside the processors and connected with the processors by various well-known means.

In the embodiments described above, the components and the features of the embodiments are combined in a predetermined form. Each component or feature should be considered as an option unless otherwise expressly stated. Each component or feature may be implemented not to be associated with other components or features. Further, the embodiment may be configured by associating some components and/or features. The order of the operations described in the embodiments may be changed. Some components or features of any embodiment may be included in another embodiment or replaced with the component and the feature corresponding to another embodiment. It is apparent that the claims that are not expressly cited in the claims are combined to form an embodiment or be included in a new claim.

The embodiments may be implemented by hardware, firmware, software, or combinations thereof. In the case of implementation by hardware, according to hardware implementation, the exemplary embodiment described herein may be implemented by using one or more application-specific integrated circuits (ASICs) , digital signal processors (DSPs) , digital signal processing devices (DSPDs) , programmable logic devices (PLDs) , field programmable gate arrays (FPGAs) , processors, controllers, micro-controllers, microprocessors, and the like.

Embodiments may be practiced in other specific forms. The described embodiments are to be considered in all respects to be only illustrative and not restrictive. The scope of the invention is, therefore, indicated in the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims

A method at a user equipment (UE) , the UE is in a non Radio Resource Control (RRC) _CONNECTED state with a network device, the method comprising:

determining whether a criterion to provide the network device with an indication is met; and

in response to the criterion being met, providing the network device with the indication implicitly or explicitly, wherein the indication is associated with the UE not initiating small data transmission (SDT) to the network device.
The method of claim 1, wherein, the criterion is any of:

the repeated times of state transition between the resuming and releasing to non RRC_CONNECTED state are larger than a first predetermined value;

the repeated times of state transition between the resuming and releasing to non RRC_CONNECTED state are larger than a second predetermined value within a configured time period; and

the measured RSRP or RSRQ is lower than a third predetermined value.
The method of claim 1, wherein, the providing the network device with the indication explicitly comprises: transmitting the indication to the network device, the indication indicates that the reason for not initiating SDT is the measured RSRP being lower than SDT RSRP threshold, or the measured RSRP is not suitable for initiating SDT.
The method of claim 3, wherein the indication is carried by a resume cause in a resume request to RRC_CONNECTED state, or a MAC CE, or a message, or UCI.
The method of claim 1, wherein, the providing the network device with the indication implicitly comprises: forbidding the UE to request for SDT configuration or CG-SDT configuration for a time period.
The method of claim 1, further comprising: selecting UL carrier based on legacy selection rule.
A user equipment (UE) , comprising:

a transceiver;

a memory; and

a processor coupled to the transceiver and the memory and configured to:

determine whether a criterion to provide a network device with an indication is met; and

in response to the criterion being met, provide the network device with the indication implicitly or explicitly,

wherein the indication is associated with the UE not initiating small data transmission (SDT) to the network device, and

the UE is in a non Radio Resource Control (RRC) _CONNECTED state with the network device.
A method at a user equipment (UE) , the UE is in a non Radio Resource Control (RRC) _CONNECTED state with a network device, the method comprising:

receiving a small data transmission (SDT) configuration for SDT transmission from the network device; and

transmitting, to the network device, a reject message and/or a waittime message to reject the SDT configuration received from the network device.
The method of claim 8, wherein, when any of the following criteria is met, the reject message and/or the waittime message are transmitted:

the measured RSRP (or RSRQ) is smaller than the RSRP (or RSRQ) threshold for SDT;

the measured RSRP (or RSRQ) is smaller than the RSRP (or RSRQ) threshold for SDT minus a delta value, where the delta value is not less than 0;

the repeated times of state transition between the resuming and releasing to non RRC_CONNECTED state are larger than a first predetermined value;

the repeated times of state transition between the resuming and releasing to non RRC_CONNECTED state are larger than a second predetermined value within a configured period; and

the measured RSRP has decreased more than a changing threshold.
The method of claim 8, wherein, the reject message means that the measured RSRP falls within non-SDT selection range or the measured RSRP is not suitable for SDT; and the waittime message indicates a time period after which the UE releases to non RRC_CONNECTED state, or a time period after which the UE is expected to be configured with SDT configuration.
A method at a network device, where a user equipment (UE) is in a non Radio Resource Control (RRC) _CONNECTED with the network device, the method comprising:

transmitting a small data transmission (SDT) configuration for SDT transmission to the UE; and

receiving, from the UE, a reject message and/or a waittime message to reject the SDT configuration.
The method of claim 11, wherein, the reject message means that the measured RSRP falls within non-SDT selection range or the measured RSRP is not suitable for SDT; and the waittime message indicates a time period after which the UE releases to non RRC_CONNECTED state, or a time period after which the UE is expected to be configured with SDT configuration.
The method of claim12, further comprising: transmitting an SDT configuration to the UE after the time period indicated by the waittime message, or after the UE reports a higher RSRP, or after the UE requests for the SDT configuration.
A user equipment (UE) , comprising:

a transceiver;

a memory; and

a processor coupled to the transceiver and the memory and configured to:

configure the transceiver to receive an SDT configuration for SDT transmission from a network device; and

configure the transceiver to transmit, to the network device, a reject message and/or a waittime message to reject the SDT configuration received from the network device, wherein

the UE is in a non Radio Resource Control (RRC) _CONNECTED state with the network device.
A network device, where a user equipment (UE) is in a non Radio Resource Control (RRC) _CONNECTED with the network device, the network device comprising:

a transceiver;

a memory; and

a processor coupled to the transceiver and the memory and configured to:

configure the transceiver to transmit an SDT configuration for SDT transmission to the UE; and

configure the transceiver to receive, from the UE, a reject message and/or a waittime message to reject the SDT configuration.