Mobile terminated small data transmission

Abstract

In accordance with some example embodiments of the present disclosure, a solution for mobile terminated small data transmission (MT-SDT) is provided. In the scheme, an RRC entity indicates first information associated with an MT-SDT process to an MAC entity. The MAC entity checks one or more conditions related to the initiation of the MT-SDT process based on the first information. The MAC entity indicates second information to the RRC entity, the second information relating to a result of the condition check. Based on the second information, the RRC entity may determine whether to initiate the MT-SDT procedure.

Description

TECHNICAL FIELD

[0001] Various example embodiments of the present disclosure generally relate to the field of telecommunications, and in particular, to methods, apparatuses, and computer-readable storage media for mobile terminated small data transmission (MT-SDT). BACKGROUND

[0002] With the development of communication systems, new technologies have been proposed. For example, small data transmission (SDT) has been proposed. Specifically, SDT is a transmission for short data burst in a connectionless state, in which a terminal device (e.g., a user equipment, UE) does not need to establish and release a connection when a small amount of data needs to be transmitted. In addition to mobile originated small data transmission (MO-SDT), mobile terminated small data transmission (MT-SDT) has also been proposed. Therefore, it is worth studying MT-SDT. SUMMARY

[0003] In a first aspect of the present disclosure, an apparatus is provided. The apparatus includes at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to at least perform: indicating, by a radio resource control (RRC) entity of the apparatus, first information associated with a MT-SDT procedure to a medium access control (MAC) entity of the apparatus; determining, by the MAC entity, whether one or more conditions related to initiation of the MT-SDT procedure are satisfied based on the first information; indicating, by the MAC entity, second information to the RRC entity based on the determination; and determining, by the RRC entity, whether to initiate the MT-SDT procedure based on the second information.

[0004] In a second aspect of the present disclosure, a method is provided. The method includes: indicating, by a RRC entity of a terminal device, first information associated with a MT-SDT procedure to a MAC entity of the terminal device; determining, by the MAC entity, whether one or more conditions related to initiation of the MT-SDT procedure are satisfied based on the first information; indicating, by the MAC entity, second information to the RRC entity based on the determination; and determining, by the RRC entity, whether to initiate the MT-SDT procedure based on the second information.

[0005] In a third aspect of the present disclosure, an apparatus is provided. The apparatus includes: means for indicating, by a RRC entity of the apparatus, first information associated with a MT-SDT procedure to a MAC entity of the apparatus; means for determining, by the MAC entity, whether one or more conditions related to initiation of the MT-SDT procedure are satisfied based on the first information; means for indicating, by the MAC entity, second information to the RRC entity based on the determination; and means for determining, by the RRC entity, whether to initiate the MT-SDT procedure based on the second information.

[0006] In a fourth aspect of the disclosure, a computer readable medium is provided. The computer readable medium comprises instructions stored thereon for causing an apparatus to perform at least the method according to the second aspect.

[0007] It is to be understood that the Summary is not intended to identify key or essential features of embodiments of the disclosure, nor is it intended to be used to limit the scope of the disclosure. Other features, details, and alternatives of the disclosure will become apparent to persons of ordinary skill in the art from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0008] Some example embodiments will now be described with reference to the accompanying drawings, in which: Figure 1 An example communication environment in which example embodiments of the disclosure can be implemented is illustrated; Figures 2A to 2C An example signalling diagram for SDT is illustrated; Figure 3 A signalling diagram for communication according to some example embodiments of the disclosure is illustrated; Figure 4 A flow diagram of a method implemented at a terminal device according to some example embodiments of the disclosure is illustrated; Figure 5 A simplified block diagram of a device suitable for implementing example embodiments of the disclosure is illustrated; and Figure 6 A block diagram of an example computer readable medium according to some example embodiments of the disclosure is illustrated.

[0009] Throughout the drawings, the same or similar reference numerals and characters may be used to denote like features, components or elements. DETAILED DESCRIPTION

[0010] The principles of the disclosure will now be described with reference to some example implementations. It is to be understood that the description of these implementations is merely intended to be illustrative and help the person skilled in the art to understand and implement the disclosure, and does not imply any limitation on the scope of the disclosure. The implementations described herein can be implemented in various ways other than those described below.

[0011] In the following description and claims, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0012] References in the present disclosure to “one embodiment,” “an embodiment,” “example embodiments,” and the like indicate that the embodiment described can include a particular feature, structure, or characteristic, but not every embodiment necessarily includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Furthermore, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of those skilled in the art to effect such feature, structure, or characteristic in connection with other

[0013] It should be understood that although the terms “first,” “second,” “third,” etc. can be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed terms.

[0014] As used herein, “at least one of ” and “one or more of ,” along with similar phrases, means that at least one of the listed elements is present in any combination. It is not required for all of the elements identified in the provided list to be present or that the elements be present every time a particular combination is identified.

[0015] As used herein, unless expressly stated otherwise, performing a step “in response to A” does not indicate that the step is performed immediately following the occurrence of “A,” and can include one or more intervening steps.

[0016] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes” and / or “including,” when used herein, specify the presence of stated features, elements and / or components, but do not preclude the presence or addition of one or more other features, elements, components and / or groups thereof.

[0017] The term “circuitry” used in this application can refer to one or more or all of the following: (a) hardware-only circuit implementations such as implementations in only analog and / or digital circuitry and (b) combinations of hardware circuits and software such as, as applicable: (i) combinations of analog and / or digital hardware circuits with software / firmware and (ii) any portion of hardware processor(s) with software, including digital signal processor(s), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions and (c) hardware circuitry and / or processor(s), such as microprocessor(s) or a portion of microprocessor(s), that requires software, e.g., firmware for operation, but that does not necessarily require software when that software is not needed for operation.

[0018] The definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers implementations including, but not limited to, hardware-only circuitry or processor(s) (or multiple processors) or hardware and software and / or firmware that work together to achieve a result. The term circuitry also encompasses, for example, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in a server, cellular network device, or other computing or network device, as applicable to a particular claim element.

[0019] As used herein, the term “communication network” refers to a network that follows any suitable communication standard, such as New Radio (NR), Long Term Evolution (LTE), LTE-Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA), High-Speed Packet Access (HSPA), Narrow Band Internet of Things (NB-IoT), etc. In addition, communication between terminal devices and network devices in a communication network can be performed according to a suitable generation of communication protocols, including but not limited to first generation (1G), second generation (2G), 2.5G, 2.75G, third generation (3G), fourth generation (4G), 4.5G, fifth generation (5G), sixth generation (6G) communication protocols, and / or any other protocols that are currently known or developed in the future. Embodiments of the present disclosure can be applied in various communication systems. In view of the rapid development in communications, it is certain that there will be future types of communication technologies and systems that can implement the present disclosure. The scope of the present disclosure should not be limited to the above-mentioned systems only.

[0020] As used herein, the term “network device” refers to a node in a communication network via which terminal devices access the network and receive services therefrom. A network device can refer to a base station (BS) or an access point (AP), such as a NodeB (NB), an evolved NodeB (eNodeB or eNB), an NR NB (also referred to as gNB), a remote radio unit (RRU), a radio head (RH), a remote radio head (RRH), a relay, an integrated access and backhaul (IAB) node, a low power node (such as a femto, pico, non-terrestrial network (NTN)), or a non-terrestrial network device (such as a satellite network device, low earth orbit (LEO) satellite, and geosynchronous earth orbit (GEO) satellite, airplane network device), and the like, depending on the terminology used and the technology applied. In some example embodiments, a radio access network (RAN) split architecture includes a centralized unit (CU) and a distributed unit (DU) located at an IAB donor node. An IAB node includes a mobile termination (IAB-MT) part that behaves like a UE towards a parent node, and a DU part of the IAB node that behaves like a base station towards a next-hop IAB node.

[0021] The term “terminal device” refers to any end device that can be capable of wireless communication. By way of example, and without limitation, a terminal device can also be referred to as a communication device, user equipment (UE), subscriber station (SS), portable subscriber station, mobile station (MS), or access terminal (AT). A terminal device can include, but is not limited to, a mobile telephone, a cellular telephone, a smart phone, a voice over Internet Protocol (VoIP) telephone, a wireless local loop telephone, a tablet, a wearable terminal device, a personal digital assistant (PDA), a portable computer, a desktop computer, an image capture terminal device, such as a digital camera, a game terminal device, a music storage and playback appliance, a vehicle-mounted wireless terminal device, a wireless endpoint, a mobile station, a laptop-embedded equipment (LEE), a laptop-mounted equipment (LME), a USB dongle, a smart device, a wireless customer-premise equipment (CPE), an Internet of Things (loT) device, a watch or other wearable device, a head-mounted display (HMD), a vehicle, a drone, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in industrial and / or

[0022] As used herein, the term “resource,” “transmission resource,” “resource block,” “physical resource block” (PRB), “uplink resource,” or “downlink resource” can refer to any resource used to perform communication, e.g., communication between a terminal device and a network device, such as a time domain resource, a frequency domain resource, a spatial domain resource, a code domain resource, or any other combination of time domain resources, frequency domain resources, spatial domain resources, code domain resources capable of communication, etc. Hereinafter, unless explicitly stated, resources in both frequency and time domains will be used as an example of transmission resources to describe some example embodiments of the present disclosure. Note that example embodiments of the present disclosure are equally applicable to other resources in other domains.

[0023] As used herein, the term “SDT” can refer to a procedure that allows data and / or signaling transmission while remaining in the RRC_INACTIVE state (i.e., without transitioning to the RRC_CONNECTED state). Specifically, SDT is a transmission for short data burst in a connectionless state, where the device does not need to establish and release a connection when a small amount of data needs to be transmitted.

[0024] As used herein, the term “common random access (RA)” can refer to a random access that is not dedicated to SDT. Similarly, the term “common random access channel (RACH)” or “common RA resource” can refer to a RACH or RA resource, respectively, that is not dedicated to SDT.

[0025] Figure 1 An example communication environment 100 in which example embodiments of the present disclosure can be implemented is shown. The communication environment 100 can include a terminal device 110. Hereinafter, the terminal device 110 can also be referred to as a UE.

[0026] The terminal device 110 can include or implement entities for different layers. As Figure 1 shown, the terminal device 110 can include an RRC entity 130 and a medium access control (MAC) entity 140. The RRC entity 130 and the MAC entity 140 can interact with each other. Further, one or more RRC entities can be located at the RRC layer, and one or more MAC entities can be located at the MAC layer. Hereinafter, the terms “RRC entity” and “RRC layer” can be used interchangeably, and the terms “MAC entity” and “MAC layer” can be used interchangeably, if there is no specific definition regarding the terms in the description.

[0027] The communication environment 100 can also include a network device 120. Hereinafter, the network device 120 can also be referred to as a gNB. The network device 120 can communicate with the terminal device 110.

[0028] It should be understood that Figure 1The number of network devices, terminal devices, and entities shown in the middle is given for purposes of illustration and is not intended to imply any limitations. The communication environment 100 can include any suitable number of network devices, terminal devices, and entities.

[0029] In some example embodiments, a link from a network device 120 to a terminal device 110 can be referred to as a downlink (DL), and a link from a terminal device 110 to a network device 120 can be referred to as an uplink (UL). In the DL, the network device 120 is a transmitting (TX) device (or transmitter), and the terminal device 110 is a receiving (RX) device (or receiver). In the UL, the terminal device 110 is a TX device (or transmitter), and the network device 120 is an RX device (or receiver).

[0030] Communications in the communication environment 100 can be implemented according to any suitable communication protocol(s), including but not limited to cellular communication protocols of first generation (1G), second generation (2G), third generation (3G), fourth generation (4G), fifth generation (5G), sixth generation (6G), etc., wireless local area network communication protocols such as Institute of Electrical and Electronics Engineers (IEEE) 802.11, and / or any other protocol that is currently known or later developed. Moreover, communications can utilize any suitable wireless communication techniques, including but not limited to code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), frequency division duplexing (FDD), time division duplexing (TDD), multiple-input multiple-output (MIMO), orthogonal frequency division multiple access (OFDMA), discrete Fourier transform spread OFDM (DFT-s-OFDM), and / or any other techniques that are currently known or later developed.

[0031] SDT can be applied to the communication environment 100. For example, MT-SDT and MO-SDT can be applied to the communication environment 100. MO-SDT is initiated by a terminal device on a radio bearer basis and only if all radio bearers for which SDT is enabled have less than a configured amount of UL data waiting for transmission, a DL reference signal received power (RSRP) is above a configured threshold, and a valid SDT resource is available. Figures 2A to 2C An example of a signaling diagram for SDT that can be applied to the communication environment 100 is shown.

[0032] Figure 2A A signaling diagram 200A for interactions for 4-step random access channel (RACH) based SDT (i.e., 4-step RA-SDT) is shown. As Figure 2AAs shown, when the terminal device 110 is in a radio resource control (RRC) inactive state, the terminal device 110 can send (2010) a message 1 (MSG 1) to the network device 120. The MSG 1 includes a preamble for RACH. The network device 120 can send (2020) a message 2 (MSG 2) to the terminal device 110. The MSG 2 includes a random access response. The terminal device 110 can send (2030) a message 3 (MSG 3) to the network device 120. The MSG 3 includes an RRC connection resume request. A small payload (i.e., small data) can be sent in the MSG 3. For example, the small payload can be multiplexed with the RRC connection resume request. The network device 120 can send (2040) an RRC release message. Figure 2B A signaling diagram 200B showing interactions for 2-step RACH based SDT (i.e., 2-step RA-SDT) is shown. As Figure 2B As shown, when the terminal device 110 is in an RRC inactive state, the terminal device 110 can send (2110) a message A (MSG A) to the network device 120. The MSG A can include a preamble for RACH. Small data can be sent with the MSG A. Specifically, the small data can be sent on a physical uplink shared channel (PUSCH) resource pre-configured by the network device 120 and broadcasted in system information with associated physical transmission parameters. The network device 120 can send (2120) a message B (MSG B) to the terminal device 110. The MSG B includes a random access response. Figure 2C A signaling diagram 200C showing interactions for configuration grant based SDT (i.e., CG-SDT) is shown. When the terminal device 110 is in an RRC connected state, the terminal device 110 can receive (2210) a CG Type 1 configuration indicating a specific pre-configured PUSCH resource to be used for UL data transmission in RRC inactive as long as timing alignment is valid. The network device 120 can send (2220) an RRC release message.

[0033] MO-SDT has been specified for new radio (NR). SDT is a procedure that allows data and / or signaling transmission while remaining in RRC_INACTIVE state (i.e., without transitioning to RRC_CONNECTED state). SDT is enabled on a radio bearer basis and MO-SDT is initiated by the UE only if there is less than a configured amount of UL data waiting for transmission on all radio bearers for which SDT is enabled, DL RSRP is above a configured threshold, and valid SDT resources are available.

[0034] The SDT procedure is initiated by the UE through RACH (via system information configuration) or Type 1 CG resources (via dedicated signaling). RRCReleaseor dedicated signaling in other RRC messages or information elements (IEs) configured) on the transmission. SDT resources can be configured on the initial bandwidth part (BWP) for both RACH and CG. RACH and CG resources for SDT can be configured on either or both of a non-supplemental uplink (NUL) and a supplemental uplink (SUL) carrier. When receiving RRCRelease a message with suspend indication, CG resources for SDT are only valid within the UE's primary cell (PCell). CG resources are associated with one or more SSBs. For RACH, the network can configure 2-step RA resources and / or 4-step RA resources for SDT. When both 2-step RA resources and 4-step RA resources for SDT are configured, the UE selects the RA type. For SDT on RACH, contention-free random access (CFRA) is not supported.

[0035] Once initiated, the SDT procedure is: - successfully completed after the UE points to RRC_IDLE (via RRCRelease ) or continues RRC_INACTIVE (via RRCRelease or RRCReject ) or RRC_CONNECTED (via RRCResume or RRCSetup ); or - unsuccessfully completed in case of cell reselection, SDT failure detection timer expiry, the MAC entity reaches the configured maximum PRACH preamble transmission threshold, the RLC entity reaches the configured maximum retransmission threshold, or when the SDT procedure is ongoing on CG and the UE has not received a response from the network after the initial PUSCH transmission, the SDT dedicated timing alignment timer expires.

[0036] In response to the SDT procedure not being successfully completed, the UE transitions to RRC_IDLE.

[0037] The initial PUSCH transmission during the SDT procedure includes at least a common control channel (CCCH) message. When CG resources are used for the initial SDT transmission, the UE can perform autonomous retransmission of the initial transmission if it does not receive an acknowledgement (dynamic UL grant or DL assignment) from the network before the expiry of the configured timer. Subsequent transmissions after the initial PUSCH transmission are handled differently depending on the type of resources used to initiate the SDT procedure: - When CG resources are used, the network can schedule subsequent UL transmissions using dynamic grant or they can occur at the following CG resource occasions. DL transmissions are scheduled using dynamic allocation. The UE can initiate subsequent UL transmissions only after receiving an acknowledgement from the network for the initial PUSCH transmission (dynamic UL grant or DL allocation). For subsequent UL transmissions, the UE cannot initiate retransmissions on CG resources.

[0038] - When RACH resources are used, after the RA procedure is completed, the network can schedule subsequent UL and DL transmissions using dynamic UL grant and DL allocation, respectively.

[0039] While the SDT procedure is ongoing, if data appears in the buffer of any radio bearer that is not enabled for SDT, the UE initiates the transmission of a non-SDT data arrival indication to the network using UEAssistanceInformation message and, if available, including the resume cause.

[0040] The SDT procedure on CG resources can only be initiated with valid UL timing alignment. The UL timing alignment is maintained by the UE based on the SDT dedicated timing alignment timer configured by the network via dedicated signaling and, for the initial CG-SDT transmission, also by the configured number of highest ranked SSBs with DL RSRP above a configured RSRP threshold. In response to the SDT dedicated timing alignment timer expiry, the CG resources are released while maintaining the CG resource configuration.

[0041] Logical channel restrictions, if any, configured by the network in the RRCRelease message during RRC_CONNECTED state and / or in the logical channel restriction information element in the

[0042] When receiving a RRCRelease message with suspend indication, the UE initiates the SDT in the PCell of the UE or when the UE initiates the SDT in a cell that is in the UE's radio notification area (RNA), the network can configure the UE to apply robust header compression (ROHC) continuity for the SDT.

[0043] The above aspects relate to MO-SDT. Currently, there is ongoing study on MT-SDT for NR. For example, Release (Rel)-17 specifies MO-SDT to allow for small packet transmission for UL-oriented packets. For DL, MT-SDT (i.e., DL triggered small data) allows similar benefits, e.g., 1) reduced signaling overhead and UE power consumption by not transitioning to RRC_CONNECTED, and reduced latency by allowing fast transmission of (small and infrequent) packets, e.g., for positioning.

[0044] One objective is to specify support for paging triggered SDT (i.e., MT-SDT), including MT-SDT triggering mechanism for UEs in RRC_INACTIVE, support of RA-SDT and CG-SDT as UL response; MT-SDT procedure for initial DL data reception and subsequent UL / DL data transmission in RRC_INACTIVE.

[0045] For MT-SDT, some consensus has been reached. For RAN paging, MT-SDT indication (at least one bit) is explicitly included per UE via paging message. In some example embodiments, Rel-18 MT-SDT reuses the RA-SDT and CG SDT solutions / procedures specified in Rel-17 as baseline after detecting MT-SDT paging trigger. The UE can use non-SDT random access resources to access the network for MT-SDT transmission. The UE can also use configured grant resources and / or MO-RA resources. The network should be able to distinguish why the UL access is triggered, i.e., implicit or explicit indication by the UE. MT-SDT is data belonging to bearers configured for SDT. The configuration can be MO-SDT specific or MT-SDT specific. The network can only trigger MT-SDT if the data belongs to these bearers. The network can only configure MT-SDT without MO-SDT RA resources and / or CG-SDT. Similar to MO-SDT procedure, subsequent UL / DL data belonging to SDT bearers are allowed while in INACTIVE. A new resume cause in RRC resume can be introduced, one codepoint MT-SDT indication.

[0046] Further, a one-bit indication can be included in paging to trigger MT-SDT. It is ensured that a common control channel (CCCH) message can be sent over CG. The indication can be per UE. In case the conditions for paging triggered MT-SDT are not met, the UE initiates RRC resume procedure.

[0047] When the UE resumes MT-SDT, the UE resumes all radio bearers (RBs) configured for SDT. The RBs configured for SDT are common for MO-SDT and MT-SDT. If there is a valid CG-SDT resource, the UE shall use CG-SDT to send the response. When SDT is initiated due to MT-SDT, the UE can exchange subsequent DL / UL SDT data on the resumed RBs.

[0048] There is a need to specify the RRC procedure for RRC resume for MT-SDT initiation without checking the availability of UL data (i.e. if MT-SDT is initiated first, the resume cause is set to MT-SDT). It can be allowed for the UE to initiate MO-SDT based resume or non-SDT based resume at any point (before initiating RRCResumeRequest for MT-SDT) using a separate procedure. If MT-SDT procedure is initiated, for RACH during subsequent data transfer (i.e. RACH triggered due to scheduling request), the UE can use only non-SDT RACH resources (i.e. like traditional way).

[0049] In view of the above, it seems that MO-SDT-RA resources can not be used for MT-SDT as for MT-SDT initiation, the UE will not check the availability of UL data. However, the UE is able to trigger MO-SDT in case the UE has UL data in the buffer and thus naturally uses MO-SDT-RA resources in this case as well. Therefore, RACH based MT-SDT will use common RACH which is not dedicated for SDT.

[0050] For MO-SDT, the MAC layer only indicates that the SDT procedure can be initiated from the MAC perspective without providing any information about SDT resources which are valid for the use of SDT. This principle does not work for MT-SDT if MO-SDT RACH resources shall not be used by MT-SDT procedure. Some solutions do not consider the nature of MT-SDT where RA-SDT cannot be used by MT-SDT while common RACH is not used for MT-SDT as well.

[0051] According to some example embodiments of the present disclosure, a solution for MT-SDT is provided. In this solution, an RRC entity indicates a first information associated with a MT-SDT procedure to a MAC entity. The MAC entity checks one or more conditions related to initiation of the MT-SDT procedure based on the first information. The MAC entity indicates a second information to the RRC entity, the second information related to a result of the condition check. Based on the second information, the RRC entity can determine whether to initiate the MT-SDT procedure. In this way, the interaction between RRC and MAC layer is specified to support MT-SDT.

[0052] Example embodiments of the present disclosure will be described in detail below with reference to the attached drawings.

[0053] Reference will now be made to Figure 3 , which shows a signaling diagram 300 for communication according to some example embodiments of the present disclosure. As Figure 3 shown, the signaling diagram 300 involves a terminal device 110 and a network device 120. For purposes of discussion, the signaling diagram 300 is described with reference to Figure 1 .

[0054] In some example embodiments, the terminal device 110 can receive (305) an SDT configuration from the network device 120. For example, the SDT configuration can include a RACH configuration, a CG configuration (e.g., via an IE cg-SDT-config), a configuration(s) for a service radio bearer (SRB) / data radio bearer (DRB) that is used for SDT, a DRB list, etc. The SDT configuration can be received via any suitable signaling, such as via an information element (IE) sdt-Config , an IE sdt-ConfigCommon , and / or other RRC IE or message.

[0055] In some example embodiments, the terminal device 110 can receive a paging message from the network device 120. The paging message can indicate the terminal device 110 to initiate a MT-SDT procedure. In other words, the paging message can be used to trigger the MT-SDT procedure. As an example, the paging message can be a message PagingRecord .

[0056] In response to triggering the MT-SDT procedure, e.g., in response to receiving the paging message, the RRC entity 130 of the terminal device 110 can indicate (310) a first information associated with the MT-SDT procedure to the MAC entity 140 of the terminal device 110.

[0057] Based on the first information, the MAC entity 140 can check 315 one or more conditions related to the initiation of the MT-SDT procedure, which can be referred to as initiation conditions. In other words, the MAC entity can determine whether one or more initiation conditions are fulfilled. The first information triggers the condition check at the MAC entity 140 The first information can comprise any suitable indication. In some example embodiments, the first information can comprise a general indication to check one or more initiation conditions. For example, the RRC entity 130 can indicate to the MAC entity 140 to check whether the MT-SDT procedure can be initiated. In this case, the MAC entity 140 can check different conditions or a different set of conditions than for the MO-SDT. For example, the data volume threshold (DVT) can not be checked.

[0058] Alternatively, the first information can comprise a specific indication to check a condition of the one or more initiation conditions. In some example embodiments, the first information can indicate to the MAC entity 140 to check a condition for initiating the SDT procedure via resources for a CG-SDT procedure, which is also referred to as CG-SDT resources. For example, if there is no UL SDT data available for transmission in response to initiating the MT-SDT procedure, the RRC entity 130 can indicate to the MAC entity 140 to check only whether the condition for initiating the SDT procedure via CG-SDT resources is fulfilled.

[0059] The MAC entity 140 can check any suitable condition related to the initiation of the MT-SDT procedure. In some example embodiments, an RSRP threshold condition can be checked. For example, the RSRP threshold condition can comprise that the RSRP of a downlink pathloss reference is above a SDT RSRP threshold, such as sdt-RSRP-Threshold If the SDT RSRP threshold is not configured, the RSRP threshold condition can be omitted. In some example embodiments, if the RSRP threshold condition is omitted, the condition for initiating the MT-SDT can always be true and the MAC entity 140 can only check which resources are used.

[0060] Alternatively or additionally, in some example embodiments, a condition for initiating the SDT procedure via CG-SDT resources can be checked. For example, the condition for initiating the SDT procedure via CG-SDT resources can comprise, but is not limited to, that the serving cell is configured with a supplementary uplink, CG-SDT is configured on the selected UL carrier, and the TA for CG-SDT is valid, at least one SSB configured for CG-SDT with SS-RSRP above cg-SDT-RSRP-ThresholdSSB , and so on.

[0061] Alternatively or additionally, in some example embodiments, a condition for initiating the SDT procedure via a resource for the RA-SDT procedure (also referred to as a RA-SDT resource) can be checked. For example, the condition for initiating the SDT procedure can include, but is not limited to, selecting a set of RA resources for performing the RA-SDT on the selected UL carrier.

[0062] Alternatively or additionally, in some example embodiments, a condition for initiating the MT-SDT procedure can be checked. Alternatively or additionally, in some example embodiments, a condition for initiating the MO-SDT procedure can be checked.

[0063] By checking the one or more initiation conditions, the terminal device 110 can determine whether the MT-SDT procedure can be initiated and what resource can be used if the MT-SDT procedure can be initiated.

[0064] Continuing the signaling diagram 300, based on the result of the condition check, the MAC entity 140 can indicate (320) second information to the RRC entity 130. The second information is related to the result of the condition check.

[0065] In some example embodiments, the MAC entity 140 can indicate to the RRC entity 130 that the condition for initiating the MT-SDT procedure is fulfilled or that the MT-SDT procedure can be initiated, which is also referred to as a general indication. Such a general indication can not include information about what resource can be used. In some example embodiments, the MAC entity 140 can also indicate to the RRC entity 130 which resource can be used for the MT-SDT procedure, which is also referred to as a specific indication. For example, the MAC entity 140 can indicate to the RRC entity 130 that the condition for initiating the SDT procedure via the CG-SDT resource is fulfilled. In some example embodiments, the MAC entity 140 can indicate to the RRC entity 130 that some or all of the conditions for initiating the MT-SDT procedure are not fulfilled.

[0066] The RRC entity 130 can then determine (325) whether to initiate the MT-SDT procedure based on the second information. In some example embodiments, the MT-SDT procedure can be initiated, for example, using the CG-SDT resource or the common RA resource. In some other example embodiments, the MT-SDT procedure can not be initiated. Instead, a non-SDT recovery procedure or a MO-SDT procedure can be initiated. A transmission to the network device 120 can then be performed (330). Alternatively, the terminal device 110 can not initiate any procedure in response to the paging message from the network device 120.

[0067] In some example embodiments, the RRC entity 130 can initiate the MT-SDT procedure only if the MAC entity 140 indicates to the RRC entity 130 that the conditions for initiating the MT-SDT procedure are met or the MT-SDT procedure can be initiated. The RRC entity 130 can instruct the MAC entity 140 to initiate the MT-SDT procedure and the MAC entity 140 can determine the resources to use based on the results of the condition checks. For example, if the conditions for initiating the SDT procedure via the CG-SDT resources are met, the MAC entity 140 can determine to use the CG-SDT resources. For another example, if the conditions for initiating the SDT procedure via the CG-SDT resources are not met but the RSRP threshold condition is met, the MAC entity 140 can determine to use the common RA resources.

[0068] In some example embodiments, the RRC entity 130 can determine which resources are used for the MT-SDT procedure. In an example, based on the second information from the MAC entity 140, the RRC entity 130 can initiate the MT-SDT procedure using the CG-SDT resources. In another example, based on the second information from the MAC entity 140, the RRC entity 130 can initiate the MT-SDT procedure using the common RA resources. For example, the RRC entity 130 can instruct the MAC entity 140 to initiate the RA procedure.

[0069] The above describes example interaction procedures between the MAC entity 140 and the RRC entity 130. More example embodiments regarding the condition checks and interactions are now described.

[0070] In some example embodiments, the RSRP threshold condition and / or the conditions for initiating the SDT procedure via the CG-SDT resources can be checked by the MAC entity 140. For example, if the RRC entity 130 instructs the MAC entity 140 to check whether the MT-SDT procedure can be initiated, the MAC entity 140 can only check whether the RSRP threshold condition and / or the conditions for initiating the SDT procedure via the CG-SDT resources are met.

[0071] In some example embodiments, the terminal device 110 can initiate the MT-SDT procedure using the CG-SDT resource if the condition for initiating the SDT procedure via the CG-SDT resource is satisfied. In an example, if the MAC entity 140 determines that the condition for initiating the SDT procedure via the CG-SDT resource is satisfied, the MAC entity 140 can indicate to the RRC entity 130 that the condition for initiating the SDT procedure via the CG-SDT resource is satisfied. Based on the indication, the RRC entity 130 can determine that the MT-SDT procedure can be initiated and the CG-SDT resource can be used. Alternatively, the MAC entity 140 can only indicate to the RRC entity 130 that the condition for initiating the MT-SDT procedure is satisfied or the MT-SDT procedure can be initiated. Thus, the RRC entity 130 can only initiate the MT-SDT procedure and then the MAC entity 140 can determine to use the CG-SDT resource for the MT-SDT.

[0072] In some example embodiments, the terminal device 110 can initiate the MT-SDT procedure using the common RA resource if the condition for initiating the SDT procedure via the CG-SDT resource is not satisfied and the RSRP threshold condition is satisfied. In an example, if the MAC entity 140 determines that the condition for initiating the SDT procedure via the CG-SDT resource is not satisfied and the RSRP threshold condition is satisfied, the MAC entity 140 can indicate to the RRC entity 130 at least one of the condition for initiating the SDT procedure via the CG-SDT resource is not satisfied, the RSRP threshold condition is satisfied, the condition for initiating the MT-SDT procedure is satisfied, or the condition for initiating the SDT procedure is satisfied. Based on such indication, the RRC entity 130 can determine that the MT-SDT procedure can be initiated and the common RA resource can be used. Alternatively, the MAC entity 140 can only indicate to the RRC entity 130 that the condition for initiating the MT-SDT procedure is satisfied or the MT-SDT procedure can be initiated. Thus, the RRC entity 130 can only initiate the MT-SDT procedure and then the MAC entity 140 can determine to use the common RA resource for the MT-SDT.

[0073] In some example embodiments, the terminal device 110 can initiate a non-SDT RRC resume procedure if the conditions for initiating the SDT procedure via the CG-SDT resource are not satisfied and the RSRP threshold condition is not satisfied. In an example, the MAC entity 140 can indicate to the RRC entity 130 at least one of the following: the conditions for initiating the MT-SDT procedure are not satisfied, or the conditions for initiating the SDT procedure are not satisfied, if the MAC entity 140 determines that the conditions for initiating the SDT procedure via the CG-SDT resource are not satisfied and the RSRP threshold condition is not satisfied. Based on the indication, the RRC entity 130 can determine that the MT-SDT procedure cannot be initiated and can instead initiate a non-SDT RRC resume procedure.

[0074] In the above example embodiments, the conditions for initiating the SDT procedure via the CG-SDT resource and / or the RSRP threshold condition are checked. By way of example only and without any limitation, an example implementation of a technical specification (e.g., TS 38.221) can be as follows: The MAC entity can be configured by RRC with SDT and the SDT procedure can be initiated by the RRC layer. The SDT procedure can be performed through a random access procedure with 2-step RA type or 4-step RA type (i.e., RA-SDT) or through configured grant Type 1 (i.e., CG-SDT).

[0075] The RRC configures the following parameters for the SDT procedure: - sdt-DataVolumeThreshold sdt-DataVolumeThreshold: Data volume threshold for the UE to determine whether to perform the SDT procedure; - sdt-RSRP-Threshold sdt-RSRP-ThresholdSSB: RSRP threshold for the UE to determine whether to perform the SDT procedure; - cg-SDT-RSRP-ThresholdSSB sdt-RSRP-ThresholdSSB-ForCG-SDT: Configures the RSRP threshold for SSB selection for CG-SDT.

[0076] If the SDT procedure is initiated by the upper layer, the MAC entity shall: 1> if the data volume of UL data pending on all RBs configured for SDT is less than or equal to sdt-DataVolumeThreshold, or if the SDT procedure is initiated for MT-SDT; and NOTE: For the SDT procedure, the MAC entity also considers the suspended RBs configured with SDT for data volume calculation. It is up to UE implementation how the UE calculates the data volume for the suspended RBs. The size of CCCH message is not considered for data volume calculation.

[0077] 1> if the RSRP of the downlink pathloss reference is higher than sdt-RSRP-Threshold; or 1> if sdt-RSRP-Threshold is not configured: 2> if the serving cell is configured with a Scheduling Request configured as specified in TS 38.331 [5]; and 2> if the RSRP of the downlink pathloss reference is less than rsrp-ThresholdSSB-SUL : 3> select the SUL carrier.

[0078] 2> else: 3> select the NUL carrier.

[0079] 2> if CG-SDT is configured on the selected UL carrier and the TA for CG-SDT is valid according to clause 5.27.2 in the first available CG occasion (according to clause 5.8.2) for initial CG-SDT transmission with a CCCH message; and 2> for each RB with data available for transmission, if configureGrantType1Allowed (if configured) is configured to true for the corresponding logical channel; and 2> if at least one SSB with SS-RSRP higher than cg-SDT-RSRP-ThresholdSSB configured for CG-SDT is available: 3> if the SDT procedure is initiated by upper layers for MT-SDT: 4> indicate to upper layers that the conditions for initiating a CG-SDT procedure are met.

[0080] 3> else: 4> indicate to upper layers that the conditions for initiating a SDT procedure are met; 3> perform a CG-SDT procedure on the selected UL carrier according to clause 5.8.2. 2> else if the SDT procedure is initiated by upper layers for MT-SDT: 3> indicate to upper layers that the conditions for initiating a CG-SDT procedure are not met, or (alternatively) indicate to upper layers that the conditions for initiating a SDT procedure are met, or (alternatively) indicate to upper layers that the RSRP of the downlink pathloss reference is higher than sdt-RSRP-Threshold.

[0081] 2> else if the SDT procedure is not initiated by upper layers for MT-SDT; and 2> if the set of random access resources for performing RA-SDT is selected according to entry 5.1.1b on the selected UL carrier: 3> if the cg-SDT-TimeAligmentTimer is running, consider the cg-SDT-TimeAligmentTimer expired and perform the corresponding actions in entry 5.2; 3> indicate to upper layers that the conditions for initiating the SDT procedure are fulfilled.

[0082] 2> else: 3> indicate to upper layers that the conditions for initiating the SDT procedure are not fulfilled.

[0083] 1> else: 2> indicate to upper layers that the conditions for initiating the SDT procedure are not fulfilled.

[0084] Another example implementation of the technical specification (e.g., TS 38.331) with respect to the conditions for initiating the MT-SDT can be as follows: When all the following conditions are fulfilled, the UE in RRC_INACTIVE initiates the resume procedure for MT-SDT: 1> the PagingRecord includes an indication for initiating the MT-SDT; and 1> the SIB1 includes sdt-ConfigCommon; and 1> the sdt-Config is configured; and 1> when initiated, the lower layers indicate that the conditions for initiating the MT-SDT are fulfilled as specified in TS 38.321 [3].

[0085] Another example implementation of the technical specification (e.g., TS 38.331) with respect to the initiation can be as follows: In response to initiating the procedure, the UE shall: 1> if sdt-MAC-PHY-CG-Config is configured: 2> if the resume procedure is initiated in a cell different from the PCell where the UE received the stored sdt-MAC-PHY-CG-Config: 3> release the stored sdt-MAC-PHY-CG-Config; 3> if running, instruct the MAC entity to stop the cg-SDT-TimeAligmentTimer; 1> if the conditions for initiating the SDT are fulfilled according to section 5.3.13.1b of TS 38.331 for MO-SDT; or 1> if the conditions for initiating SDT are fulfilled according to clause 5.3.13.1c of TS 38.331 for MT-SDT: 2> consider that the resume procedure is initiated for SDT; 2> if the low layer indicates that the conditions for initiating the CG-SDT procedure are not fulfilled, or (alternatively) the low layer indicates that the conditions for initiating the SDT procedure are fulfilled, or (alternatively) the low layer indicates that the RSRP of the downlink pathloss reference is higher than sdt-RSRP-Threshold: 3> indicate to the low layers to initiate a random access procedure as specified in TS 38.321 [3]; 2> start timer T319a when the low layer first transmits a CCCH message; 2> consider that the SDT procedure is ongoing; 1> else: 2> start timer T319; 2> if running, instruct the MAC entity to stop cg-SDT-TimeAligmentTimer; 1> if ta-Report is configured with a value enable and the UE supports TA reporting: 2> indicate to the low layers that TA reporting is initiated; 1> set the variable pendingRNA-Update to false; 1> if stored, release successHO-Config from the UE Inactive AS context; 1> initiate transmission of the RRCResumeRequest message or RRCResumeRequest1 according to clause 5.3.13.3 of TS 38.331 Additionally or alternatively, some other conditions can be checked in addition to the conditions for initiating the SDT procedure via CG-SDT resources and / or the RSRP threshold condition.

[0086] In some example embodiments, the conditions for initiating the SDT procedure via CG-SDT resources, the conditions for initiating the SDT procedure via RA-SDT resources and / or the UL SDT data can be checked. For example, if the RRC entity 130 indicates to the MAC entity 140 to check whether the MT-SDT procedure can be initiated, the MAC entity 140 can check these conditions.

[0087] In some example embodiments, if the conditions for initiating the SDT procedure via the CG-SDT resource are not met, UL SDT data is available, and the conditions for initiating the SDT procedure via the RA-SDT resource are met, the terminal device 110 can initiate a MO-SDT procedure or a non-SDT RRC resume procedure. For example, if the available UL SDT data is associated with a radio bearer configured with SDT, the MO-SDT procedure can be initiated. Otherwise, the non-SDT RRC resume procedure can be initiated.

[0088] In an example, the RRC entity 130 can indicate to the MAC entity 140 to check whether the MT-SDT can be initiated. Based on the indication, the MAC entity 140 can check whether the conditions for initiating the SDT procedure via the CG-SDT resource are met. If the conditions for initiating the SDT procedure via the CG-SDT resource are not met, the MAC entity 140 can determine whether there is UL SDT data available for transmission. If there is UL SDT data available for transmission, the MAC entity 140 can check whether the conditions for initiating the SDT procedure via the RA-SDT resource are met. If the conditions for initiating the SDT procedure via the RA-SDT resource are met, the MAC entity 140 can indicate to the RRC entity 130 that the conditions for initiating the SDT procedure via the RA-SDT resource are met or the conditions for initiating the MO-SDT procedure are met.

[0089] Based on the indication from the MAC entity 140, the RRC entity 130 can determine that the MT-SDT procedure cannot be initiated, but the MO-SDT procedure can be initiated. The RRC entity 130 can initiate the MO-SDT procedure or the non-SDT RRC resume procedure.

[0090] In such example embodiments, in the case where there is available UL SDT data, MO-SDT can be triggered instead of MT-SDT.

[0091] In some example embodiments, a particular condition can be checked. As an example, only a condition for initiating an SDT procedure via a CG-SDT resource can be checked. For example, if there is no UL SDT data available for transmission in response to initiating an MT-SDT procedure, the RRC entity 130 can indicate to the MAC entity 140 to check whether a condition for initiating an SDT procedure via a CG-SDT resource is satisfied only. If the condition for initiating an SDT procedure via a CG-SDT resource is satisfied, the terminal device 110 can initiate an MT-SDT procedure using a CG-SDT resource. For example, the MAC entity 140 can indicate to the RRC entity 130 that the condition for initiating an SDT procedure via a CG-SDT resource is satisfied or that the condition for initiating an MT-SDT procedure is satisfied. Thus, the RRC entity 130 can initiate an MT-SDT procedure and use a CG-SDT resource.

[0092] In some example embodiments, if the condition for initiating an SDT procedure via a CG-SDT resource is not satisfied, the terminal device 110 can initiate a non-SDT RRC resume procedure. For example, the MAC entity 140 can indicate to the RRC entity 130 that the condition for initiating an SDT procedure via a CG-SDT resource is not satisfied or that the condition for initiating an MT-SDT procedure is not satisfied. Thus, the RRC entity 130 can determine that an MT-SDT procedure cannot be initiated and can instead initiate a non-SDT RRC resume procedure.

[0093] Alternatively, in some example embodiments, even if the RRC entity 130 indicates to the MAC entity 140 to check a particular condition, the MAC entity 140 can check one or more other conditions. Based on the results of the condition checks, the MAC entity 140 can indicate to the RRC entity 130 whether the particular condition is satisfied or whether one or more other conditions are satisfied or whether the condition for initiating an MT-SDT procedure is satisfied. Based on this indication from the MAC entity 140, the RRC entity 130 can determine whether to initiate an MT-SDT procedure.

[0094] As an example, the RRC entity 130 can instruct the MAC entity 140 to check a condition for initiating an SDT procedure via a CG-SDT resource. The MAC entity 140 can also check one or more other conditions, for example, an RSRP threshold condition. Then, based on the results of the condition checks, the MAC entity 140 can indicate to the RRC entity 130 whether the condition for initiating an SDT procedure via a CG-SDT resource is satisfied or whether the RSRP threshold condition is satisfied or whether the condition for initiating an MT-SDT procedure is satisfied.

[0095] The correct initiation of the MT-SDT procedure can be achieved through conditional checks and interactions between the RRC and MAC layers. Furthermore, it should be noted that the combination of different conditions described above are by way of example and not limitation.

[0096] In Figure 3 In some example embodiments, only one RRC entity 130 and one MAC entity 140 are depicted, but more than one RRC and / or MAC entity can be included in the terminal device 110.

[0097] Figure 4 A flowchart of an example method 400 implemented at a terminal device according to some example embodiments of the present disclosure is shown. For purposes of discussion, the method 400 will be described from the perspective of the terminal device 110 in Figure 1 The method 400 will be described from the perspective of the terminal device 110 in

[0098] At block 410, the RRC entity of the terminal device indicates first information associated with the MT-SDT procedure to the MAC entity of the terminal device.

[0099] At block 420, the MAC entity determines, based on the first information, whether one or more conditions related to initiation of the MT-SDT procedure are satisfied.

[0100] At block 430, the MAC entity indicates second information to the RRC entity based on the determination.

[0101] At block 440, the RRC entity determines, based on the second information, whether to initiate the MT-SDT procedure.

[0102] In some example embodiments, the one or more conditions include at least one of a reference signal received power, RSRP, threshold condition, a condition for initiating the MT-SDT procedure, a condition for initiating a small data transmission, SDT, procedure via resources for a configured grant small data transmission, CG-SDT, procedure, a condition for initiating the SDT procedure via resources for a random access small data transmission, RA-SDT, procedure, or a condition for initiating a mobile originated small data transmission, MO-SDT, procedure.

[0103] In some example embodiments, if the condition for initiating the SDT procedure via resources for the CG-SDT procedure is satisfied, the MT-SDT procedure is initiated using the resources for the CG-SDT procedure.

[0104] In some example embodiments, the second information indicates that the condition for initiating the SDT procedure via resources for the CG-SDT procedure is satisfied.

[0105] In some example embodiments, if the condition for initiating the SDT procedure via the resource for the CG-SDT procedure is not satisfied and the RSRP threshold condition is satisfied, the terminal device can initiate the MT-SDT procedure using the resource for the common random access (RA) procedure.

[0106] In some example embodiments, the second information indicates at least one of: the condition for initiating the SDT procedure via the resource for the CG-SDT procedure is not satisfied, the RSRP threshold condition is satisfied, the condition for initiating the MT-SDT procedure is satisfied, or the condition for initiating the SDT procedure is satisfied.

[0107] In some example embodiments, if the condition for initiating the SDT procedure via the resource for the CG-SDT procedure is not satisfied and the RSRP threshold condition is not satisfied, the terminal device can initiate the non-SDT RRC resume procedure.

[0108] In some example embodiments, the second information indicates at least one of: the condition for initiating the MT-SDT procedure is not satisfied, or the condition for initiating the SDT procedure is not satisfied.

[0109] In some example embodiments, if: the condition for initiating the SDT procedure via the resource for the CG-SDT procedure is not satisfied, uplink small data transmission data is available, and the condition for initiating the SDT procedure via the resource for the RA-SDT procedure is satisfied, the terminal device can initiate the MO-SDT procedure or the non-SDT RRC resume procedure.

[0110] In some example embodiments, the second information indicates at least one of: the condition for initiating the SDT procedure via the resource for the RA-SDT procedure is satisfied, or the condition for initiating the MO SDT procedure is satisfied.

[0111] In some example embodiments, if no uplink SDT data is available for transmission for the MT-SDT procedure, the first information indicates to check only the condition for initiating the SDT procedure via the resource for the CG-SDT procedure.

[0112] In some example embodiments, an apparatus (e.g., the terminal device 110 in Figure 1 ) capable of performing any one of the methods 400 can include means for performing the corresponding operations of the methods 400. The means can be implemented in any suitable form. For example, the means can be implemented in firmware or software modules. The apparatus can be implemented as or included in the terminal device 110 in Figure 1 .

[0113] In some example embodiments, the apparatus comprises: means for indicating, by a radio resource control, RRC, entity of the apparatus, first information associated with a mobile terminated small data transmission, MT-SDT, procedure to a medium access control, MAC, entity of the apparatus; means for determining, by the MAC entity, based on the first information, whether one or more conditions related to initiation of the MT-SDT procedure are satisfied; means for indicating, by the MAC entity, based on the determination, second information to the RRC entity; and means for determining, by the RRC entity, based on the second information, whether to initiate the MT-SDT procedure.

[0114] In some example embodiments, the one or more conditions comprise at least one of: a reference signal received power, RSRP, threshold condition, a condition for initiating the MT-SDT procedure, a condition for initiating the small data transmission, SDT, procedure via resources for a configured grant small data transmission, CG-SDT, procedure, a condition for initiating the SDT procedure via resources for a random access small data transmission, RA-SDT, procedure, or a condition for initiating a mobile originated small data transmission, MO-SDT, procedure.

[0115] In some example embodiments, the apparatus comprises: means for initiating the MT-SDT procedure using resources for a CG-SDT procedure if a condition for initiating the SDT procedure via resources for the CG-SDT procedure is satisfied.

[0116] In some example embodiments, the second information indicates that the condition for initiating the SDT procedure via resources for the CG-SDT procedure is satisfied.

[0117] In some example embodiments, the apparatus comprises: means for initiating the MT-SDT procedure using resources for a common random access, RA, procedure if the condition for initiating the SDT procedure via resources for the CG-SDT procedure is not satisfied and the RSRP threshold condition is satisfied.

[0118] In some example embodiments, the second information indicates at least one of: the condition for initiating the SDT procedure via resources for the CG-SDT procedure is not satisfied, the RSRP threshold condition is satisfied, the condition for initiating the MT-SDT procedure is satisfied, or the condition for initiating the SDT procedure is satisfied.

[0119] In some example embodiments, the apparatus comprises: means for initiating a non-SDT RRC resume procedure if the condition for initiating the SDT procedure via resources for the CG-SDT procedure is not satisfied and the RSRP threshold condition is not satisfied.

[0120] In some example embodiments, the second information indicates at least one of: the condition for initiating the SDT procedure via resources for the CG-SDT procedure is not satisfied, or the condition for initiating the SDT procedure via resources for the RA-SDT procedure is not satisfied.

[0121] In some example embodiments, the apparatus comprises means for initiating the MO-SDT procedure or the non-SDT RRC resume procedure if the condition for initiating the SDT procedure via resources for the CG-SDT procedure is not satisfied, uplink small data transmission data is available, and the condition for initiating the SDT procedure via resources for the RA-SDT procedure is satisfied.

[0122] In some example embodiments, the second information indicates at least one of: the condition for initiating the SDT procedure via resources for the RA-SDT procedure is satisfied, or the condition for initiating the MO SDT procedure is satisfied.

[0123] In some example embodiments, the first information indicates to check only the condition for initiating the SDT procedure via resources for the CG-SDT procedure if no uplink SDT data is available for transmission for the MT-SDT procedure.

[0124] In some example embodiments, the apparatus further comprises means for performing other operations in the method 400 or some example embodiments of the terminal device 110. In some example embodiments, the means comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to perform.

[0125] Figure 5 is a simplified block diagram of a device 500 suitable for implementing example embodiments of the present disclosure. The device 500 can be provided to implement a communication device, such as the terminal device 110 or the network device 120 shown in Figure 1 FIG. 1. As shown, the device 500 includes one or more processors 510, one or more memories 520 coupled to the processor(s) 510, and one or more communication modules 540 coupled to the processor(s) 510.

[0126] The communication module 540 is for bidirectional communication. The communication module 540 has one or more communication interfaces to facilitate communication with one or more other modules or devices. The communication interface can represent any interface necessary to communicate with other network elements. In some example embodiments, the communication module 540 can include at least one antenna.

[0127] As non-limiting examples, the processor 510 can be any type suitable for the local technological network and can include one or more of: a general purpose computer, a special purpose computer, a microprocessor, a digital signal processor (DSP), and a processor based on a multi-core processor architecture. The device 500 can have multiple processors, such as a dedicated integrated circuit chip that is time-slaved to a clock of a synchronous host processor.

[0128] The memory 520 can include one or more non-volatile memories and one or more volatile memories. Examples of non-volatile memories include, but are not limited to, read only memories (ROMs) 524, electrically programmable read only memories (EPROMs), flash memories, hard disks, compact disks (CDs), digital video disks (DVDs), optical disks, laser disks, and other magnetic and / or optical storage. Examples of volatile memories include, but are not limited to, random access memories (RAMs) 522 and other volatile memories that do not persist during power loss.

[0129] The computer program 530 includes computer-executable instructions executed by the associated processor 510. The instructions of the program 530 can include instructions for performing the operations / acts of some example embodiments of the present disclosure. The program 530 can be stored in a memory, such as the ROM 524. The processor 510 can perform any suitable actions and processes by loading the program 530 into the RAM 522.

[0130] Example embodiments of the present disclosure can be implemented with the aid of the program 530, such that the device 500 can perform any processes of the present disclosure as discussed with reference to Figures 2A to 4 Example embodiments of the present disclosure can also be implemented by hardware or by a combination of software and hardware.

[0131] In some example embodiments, the program 530 can be tangibly embodied in a computer-readable medium, which can be included in the device 500 (such as in the memory 520) or in another storage device accessible by the device 500. The device 500 can load the program 530 from the computer-readable medium into the RAM 522 for execution. In some example embodiments, the computer-readable medium can include any type of non-transitory storage medium, such as a ROM, an EPROM, a flash memory, a hard disk, a CD, a DVD, and so on. The term "non-transitory" as used herein is a limitation of the medium itself (i.e., tangible, as opposed to a signal), and not a limitation of data storage durability (e.g., RAM versus ROM).

[0132] Figure 6 An example of a computer-readable medium 600, which can be in the form of a CD, DVD, or other optical storage disk, is shown. The computer-readable medium 600 has the program 530 stored thereon.

[0133] In general, the various embodiments of the disclosure can be implemented in hardware or special-purpose circuits, software, logic or any combination thereof. Some aspects can be implemented in hardware, while other aspects can be implemented in firmware or software which can be executed by a controller, microprocessor or other computing device. While various aspects of embodiments of the disclosure are illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein can be implemented in hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controler or other computing devices, or some combination thereof.

[0134] Some example embodiments of the present disclosure also provide at least one computer program product which is tangibly stored on a computer readable medium, such as a non-transitory computer readable medium. The computer program product includes computer executable instructions, such as those included in program modules executed by devices on a target physical or virtual processor, to perform any of the methods as described above. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules can be combined or split between program modules as desired in various embodiments. Machine executable instructions for program modules can be executed locally or distributed across devices. In a distributed deice, program modules can be located in both local and remote storage media.

[0135] Program code for carrying out methods of the present disclosure can be written in any combination of one or more programming languages. The program code can be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the program code, when executed by the processor or controller, causes the machine to perform the functions / operations described in the flow diagrams and / or block diagrams. The program code can be executed entirely on a machine, partially on a machine, as a stand-alone software package, partially on a machine and partially on a remote machine or entirely on a remote machine or server.

[0136] In the context of the present disclosure, computer program code or related data can be carried by any suitable carrier to enable a device, apparatus or processor to perform the various processes and operations as described above. Examples of carriers include signals, computer readable media, etc.

[0137] The computer-readable medium can be a computer-readable signal medium or a computer-readable storage medium. It can include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of a computer-readable storage medium will include a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0138] Moreover, while operations may be depicted in the drawings in a particular, serial order, this should not be understood as requiring or implying that such operations be performed in the particular order shown, or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing can be advantageous. Likewise, while several specific implementation details are contained in the above discussion, these should not be construed as limitations on the scope of the disclosure, but merely as description of features that can be specific to particular embodiments. Certain features that are described in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable sub-combination. Moreover, although the components of the disclosure can be described in the context of a single embodiment, it will be understood that the components can be combined across embodiments.

[0139] Although the present disclosure has been described in language specific to structural features and / or methodological acts, it is to be understood that the subject of the appended claims is not necessarily limited to the specific features or acts described. Rather, the specific features and acts are disclosed as example forms of implementing the claims.

Claims

1. An apparatus comprising: At least one processor; as well as At least one memory stores instructions that, when executed by the at least one processor, cause the device to at least: The Radio Resource Control (RRC) entity of the device indicates first information associated with the Mobile Termination Small Data Transmission (MT-SDT) procedure to the Media Access Control (MAC) entity of the device. The MAC entity determines, based on the first information, whether one or more conditions related to the initiation of the MT-SDT process are met; The MAC entity indicates the second information to the RRC entity based on the determination; The RRC entity determines whether to initiate the MT-SDT process based on the second information.

2. The apparatus of claim 1, wherein the one or more conditions include at least one of the following: Reference signal received power (RSRP) threshold condition. Regarding the conditions for initiating the MT-SDT process, Conditions for initiating the Small Data Transfer SDT process via resources used to configure the authorized small data transfer CG-SDT process. Conditions for initiating the SDT process via resources used for the Random Access Small Data Transmission (RA-SDT) process, or Conditions for initiating the Mobile Small Data Transmission (MO-SDT) process.

3. The apparatus of claim 2, wherein the at least one memory stores instructions that, when executed by the at least one processor, cause the apparatus to perform the following operations: If the conditions for initiating the SDT process via the resources used for the CG-SDT process are met, the MT-SDT process is initiated using the resources used for the CG-SDT process.

4. The apparatus of claim 3, wherein the second information indicates that the condition for initiating the SDT process via the resource for the CG-SDT process is met.

5. The apparatus of claim 2, wherein the at least one memory stores instructions that, when executed by the at least one processor, cause the apparatus to perform the following operations: If the conditions for initiating the SDT procedure via the resources used for the CG-SDT procedure are not met and the RSRP threshold condition is met, the resources used for the Public Random Access (RA) procedure are used to initiate the MT-SDT procedure.

6. The apparatus of claim 5, wherein the second information indicates at least one of the following: The condition for initiating the SDT process via the resources used in the CG-SDT process was not met. The RSRP threshold condition is met. The conditions for initiating the MT-SDT procedure are met, or The conditions for initiating the SDT procedure are met.

7. The apparatus of claim 2, wherein the at least one memory stores instructions that, when executed by the at least one processor, cause the apparatus to perform the following operations: If the conditions for initiating the SDT process via the resources used in the CG-SDT process are not met and the RSRP threshold condition is not met, a non-SDT RRC recovery process is initiated.

8. The apparatus of claim 7, wherein the second information indicates at least one of the following: If the conditions for initiating the MT-SDT procedure are not met, or The conditions for initiating the SDT procedure were not met.

9. The apparatus of claim 2, wherein the at least one memory stores instructions that, when executed by the at least one processor, cause the apparatus to perform the following operations: if: The condition for initiating the SDT process via the resources used in the CG-SDT process was not met. Uplink small data transmission is available, and The conditions for initiating the SDT process via the resources used for the RA-SDT process are met. Initiate the MO-SDT process or the non-SDT RRC recovery process.

10. The apparatus of claim 9, wherein the second information indicates at least one of the following: The conditions for initiating the SDT process via the resources used in the RA-SDT process are met, or The conditions for initiating the MO SDT procedure are met.

11. The apparatus of claim 1, wherein if no uplink SDT data is available for transmission of the MT-SDT process, the first information indicates that the conditions for initiating the SDT process via resources for the CG-SDT process are checked only.

12. A method comprising: The Radio Resource Control (RRC) entity of the terminal device indicates to the Media Access Control (MAC) entity of the terminal device the first information associated with the Mobile Termination Small Data Transmission (MT-SDT) procedure; The MAC entity determines, based on the first information, whether one or more conditions related to the initiation of the MT-SDT process are met; The MAC entity indicates the second information to the RRC entity based on the determination; The RRC entity determines whether to initiate the MT-SDT process based on the second information.

13. The method of claim 12, wherein the one or more conditions include at least one of the following: Reference signal received power (RSRP) threshold condition. Regarding the conditions for initiating the MT-SDT process, Conditions for initiating the Small Data Transfer SDT process via resources used to configure the authorized small data transfer CG-SDT process. Conditions for initiating the SDT process via resources used for the Random Access Small Data Transmission (RA-SDT) process, or Conditions for initiating the Mobile Small Data Transmission (MO-SDT) process.

14. The method of claim 13, further comprising: If the conditions for initiating the SDT process via the resources used for the CG-SDT process are met, the MT-SDT process is initiated using the resources used for the CG-SDT process.

15. The method of claim 14, wherein the second information indicates that the condition for initiating the SDT process via the resource used for the CG-SDT process is met.

16. The method of claim 13, further comprising: If the conditions for initiating the SDT procedure via the resources used for the CG-SDT procedure are not met and the RSRP threshold condition is met, the resources used for the Public Random Access (RA) procedure are used to initiate the MT-SDT procedure.

17. The method of claim 16, wherein the second information indicates at least one of the following: The condition for initiating the SDT process via the resources used in the CG-SDT process was not met. The RSRP threshold condition is met. The conditions for initiating the MT-SDT procedure are met, or The conditions for initiating the SDT procedure are met.

18. The method of claim 13, further comprising: If the conditions for initiating the SDT process via the resources used in the CG-SDT process are not met and the RSRP threshold condition is not met, a non-SDT RRC recovery process is initiated.

19. The method of claim 18, wherein the second information indicates at least one of the following: If the conditions for initiating the MT-SDT procedure are not met, or The conditions for initiating the SDT procedure were not met.

20. The method of claim 13, further comprising: if: The condition for initiating the SDT process via the resources used in the CG-SDT process was not met. Uplink small data transmission is available, and The conditions for initiating the SDT process via the resources used for the RA-SDT process are met. Initiate the MO-SDT process or the non-SDT RRC recovery process.

21. The method of claim 20, wherein the second information indicates at least one of the following: The conditions for initiating the SDT process via the resources used in the RA-SDT process are met, or The conditions for initiating the MO SDT procedure are met.

22. The method of claim 12, wherein if no uplink SDT data is available for transmission of the MT-SDT procedure, the first information indicates that only conditions for initiating the SDT procedure via resources used for the CG-SDT procedure are checked.

23. An apparatus comprising: A component for instructing the device’s Media Access Control (MAC) entity, from the Radio Resource Control (RRC) entity of the device, to the device’s Media Access Control (MAC) entity, the first information associated with the Mobile Termination Small Data Transmission (MT-SDT) procedure; A component for the MAC entity to determine, based on the first information, whether one or more conditions related to the initiation of the MT-SDT process are met; A component for instructing the RRC entity with second information based on the determination by the MAC entity; as well as A component used by the RRC entity to determine whether to initiate the MT-SDT process based on the second information.

24. A computer-readable medium comprising instructions stored thereon for causing a device to perform at least the method according to any one of claims 12 to 22.

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