Terminal device, communication device, and terminal device method

Abstract

The embodiments of the present disclosure relate to a communication method, an apparatus, and a computer-readable medium, in which a terminal device receives a paging message from a network device in a radio access network, the paging message including a first indication indicating that MT-SDT is performed for the terminal device, and determines whether a random access-based MT-SDT or a configuration grant-based MT-SDT is performed for the terminal device, so that an MT-SDT procedure can be performed.

Description

[Technical field]

[0001] TECHNICAL FIELD Embodiments of the present disclosure relate generally to the field of telecommunications, and more particularly to communication methods, apparatus, and computer storage media for small data communications (SDT). [Background technology]

[0002] Typically, a terminal device in an inactive state may still have a small amount of infrequent data traffic to transmit. Until 3rd Generation Partnership Project (3GPP) Release 16, the inactive state does not support data communication, and the terminal device must resume the connection (i.e., enter the connected state) for both downlink and uplink data. This causes unnecessary power consumption and signaling overhead.

[0003] In this case, small data communication (SDT) in inactive state is approved in 3GPP Release 17. SDT is a procedure that allows data communication while remaining in inactive state (i.e. without transitioning to connected state). Thus, the signaling overhead can be reduced. In 3GPP Release 17, only mobile originated SDT (MO-SDT) is specified. MO-SDT means that the trigger of SDT in inactive state is due to the arrival of uplink (UL) data. In 3GPP Release 18, one of the possible extension aspects is mobile terminated SDT (MT-SDT). MT-SDT means that the trigger of SDT in inactive state is due to the arrival of downlink (DL) data. For now, MT-SDT related technology is still underdeveloped and further development is awaited. Summary of the Invention [Problem to be solved by the invention]

[0004] In general, the exemplary embodiments of the present disclosure provide a communication method, apparatus, and computer storage medium for MT-SDT. [Means for solving the problem]

[0005] In a first aspect, a method of communication is provided, the method including: receiving, at a terminal device, a paging message from a network device in a radio access network, the paging message including a first indication indicating that MT-SDT is performed for the terminal device, and determining whether random access based MT-SDT or configuration grant based MT-SDT is performed for the terminal device.

[0006] In a second aspect, a method of communication is provided, the method including: in a network device in a radio access network, sending a paging message to a terminal device, the paging message including a first indication indicating that an MT-SDT is to be performed for the terminal device, and receiving an initial uplink transmission of the MT-SDT from the terminal device via a random access resource or a configured grant resource.

[0007] In a third aspect, a terminal device is provided, the terminal device comprising: a processor; and a memory coupled to the processor, the memory storing instructions that, when executed by the processor, cause the terminal device to perform a method according to the first aspect of the present disclosure.

[0008] In a fourth aspect, there is provided a network device comprising a processor and a memory coupled to the processor, the memory storing instructions that, when executed by the processor, cause the network device to perform a method according to the second aspect of the present disclosure.

[0009] In a fifth aspect, a computer-readable medium is provided having instructions stored thereon that, when executed on at least one processor, cause the at least one processor to perform a method according to the first aspect of the present disclosure.

[0010] In a sixth aspect, a computer readable medium is provided having instructions stored thereon that, when executed on at least one processor, cause the at least one processor to perform a method according to the second aspect of the present disclosure.

[0011] Other features of the present disclosure will become readily apparent from the following description. [Brief description of the drawings]

[0012] The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description of several embodiments of the present disclosure in the accompanying drawings.

[0013] [Figure 1A] FIG. 1 illustrates an example communication network in which some embodiments of the present disclosure may be implemented.

[0014] [Figure 1B] FIG. 1 is a schematic diagram illustrating a user plane (UP) protocol stack in which some embodiments of the present disclosure may be implemented.

[0015] [Figure 1C] FIG. 1 is a schematic diagram illustrating a control plane (CP) protocol stack in which some embodiments of the present disclosure may be implemented.

[0016] [Figure 2A] FIG. 1 is a schematic diagram illustrating a radio access network (RAN) paging procedure in which some embodiments of the present disclosure may be implemented.

[0017] [Figure 2B] FIG. 1 is a schematic diagram illustrating a one-time SDT procedure in which some embodiments of the present disclosure can be implemented.

[0018] [Figure 2C] FIG. 1 is a schematic diagram illustrating an SDT procedure including an initial transmission and a subsequent transmission, in which some embodiments of the present disclosure can be implemented.

[0019] [Diagram 3] FIG. 2 is a schematic diagram of a communication process for MT-SDT according to an embodiment of the present disclosure.

[0020] [Figure 4A] 1 is a flowchart illustrating an exemplary process for determining an MT-SDT procedure according to a first embodiment of the present disclosure.

[0021] [Figure 4B] FIG. 4B is a schematic diagram illustrating an exemplary determination of a first time interval according to the process of FIG. 4A.

[0022] [Figure 5A] 11 is a flowchart illustrating an exemplary process for determining an MT-SDT procedure according to a second embodiment of the present disclosure.

[0023] [Figure 5B] FIG. 5B is a schematic diagram illustrating an exemplary determination of a first time interval and a second time interval according to the process of FIG. 5A.

[0024] [Figure 6A] 13 is a flowchart illustrating an exemplary process for determining an MT-SDT procedure according to a third embodiment of the present disclosure.

[0025] [Figure 6B] 13 is a flowchart illustrating an exemplary process for determining an MT-SDT procedure according to a fourth embodiment of the present disclosure.

[0026] [Figure 7A] 13 is a flowchart illustrating an exemplary process for determining an MT-SDT procedure according to a fifth embodiment of the present disclosure.

[0027] [Figure 7B] 13 is a flowchart illustrating an exemplary process for performing a Configured Grant (CG)-based MT-SDT procedure according to a sixth embodiment of the present disclosure.

[0028] [Figure 7C] 13 is a flowchart illustrating an exemplary process for performing a random access (RA) based MT-SDT procedure according to a seventh embodiment of the present disclosure.

[0029] [Figure 8] FIG. 2 illustrates an example communication method performed in a terminal device according to some embodiments of the present disclosure.

[0030] [Figure 9] FIG. 2 illustrates an example communication method performed in a network device, in accordance with some embodiments of the present disclosure.

[0031] [Figure 10] FIG. 1 is a schematic block diagram of an apparatus suitable for implementing embodiments of the present disclosure.

[0032] In the drawings, the same or similar reference numbers represent the same or similar elements. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] The principles of the present disclosure will now be described with reference to some embodiments. It should be understood that these embodiments are provided for illustrative purposes only, to assist those skilled in the art in understanding and implementing the present disclosure, and do not imply any limitations on the scope of the present disclosure. The disclosure described herein can be implemented in various ways different from those described below.

[0034] 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 pertains.

[0035] As used herein, the term "terminal device" refers to any device having wireless or wired communication capabilities. Examples of terminal devices include, but are not limited to, user equipment (UE), personal computers, desktop computers, mobile phones, cellular phones, smartphones, personal digital assistants (PDAs), portable computers, tablets, wearable devices, Internet of Things (IoT) devices, any Internet of Things (IoE) devices, machine type communication (MTC) devices, in-vehicle devices for V2X communication, etc., where the "X" in V2X represents a pedestrian, vehicle or infrastructure / network, or an image capture device such as a digital camera, a gaming device, a music storage and playback device, or an Internet appliance that allows wireless or wired Internet access and browsing, etc. The term "terminal device" may be used interchangeably with UE, mobile station, subscriber station, mobile terminal, user terminal, or wireless device. Additionally, the term "network device" refers to a device that can provide or host a cell or coverage over which the terminal device can communicate. Examples of network devices include, but are not limited to, low power nodes such as a Node B (NodeB or NB), an evolved Node B (eNodeB or eNB), a next generation Node B (gNB), a transmit / receive point (TRP), a remote radio unit (RRU), a radio head (RH), a remote radio head (RRH), a femto node, and a pico node.

[0036] In one embodiment, the terminal device can connect to a first network device and a second network device. One of the first network device and the second network device may be a master node and the other may be a secondary node. The first network device and the second network device may use different radio access technologies (RATs). In one embodiment, the first network device may be a first RAT device and the second network device may be a second RAT device. In one embodiment, the first RAT device is an eNB and the second RAT device is a gNB. Information about the different RATs may be transmitted from at least one of the first network device or the second network device to the terminal device. In one embodiment, the first information may be transmitted from the first network device to the terminal device, and the second information may be transmitted from the second network device directly or via the first network device to the terminal device. In one embodiment, information about the configuration of the terminal device configured by the second network device may be transmitted from the second network device via the first network device. Information regarding the reconfiguration of the terminal device configured by the second network device may be transmitted from the second network device directly to the terminal device or via the first network device.

[0037] As used herein, the singular forms "a," "an," and "said" include the plural forms unless the context clearly indicates otherwise. The term "comprises" and variations thereof should be understood as open-ended terms meaning "including, but not limited to." The term "based on" should be understood as "based at least in part on." The terms "one embodiment" and "embodiment" should be understood as "at least one embodiment." The term "another embodiment" should be understood as "at least one other embodiment." Terms such as "first," "second," and the like may refer to different or the same object. The following may include other explicit and implicit definitions.

[0038] In some instances, values, procedures, or devices are referred to as "best," "lowest," "highest," "minimum," "maximum," etc. It should be understood that such descriptions are intended to illustrate that selections can be made from among many functional alternatives used, and that such selections are not necessarily better, smaller, higher, or otherwise more preferred than other selections.

[0039] Traditionally, there are various applications that exchange data in small amounts and infrequently. For example, in some applications for mobile devices, SDT may include traffic from instant messaging (IM) services, such as heartbeat or keep-alive traffic from IM or email clients and other services, push notifications in various applications, traffic from wearable devices (including, for example, periodic location information), etc. In some applications for non-mobile devices, SDT may include sensor data (e.g., temperature, pressure measurements transmitted periodically or in an event-triggered manner within an IoT network), metering and alarm information sent from smart meters, etc.

[0040] Recently, it has been proposed to support paging triggered SDT (MT-SDT). Specifically, the MT-SDT trigger mechanism is supported for UEs in RRC_INACTIVE, and RA-based SDT and CG-based SDT are supported as uplink (UL) responses. In addition, the MT-SDT procedure is also supported for initial downlink (DL) data reception in RRC_INACTIVE and for subsequent UL / DL data communication. However, MT-SDT-related technologies are still immature and require further development.

[0041] In view of this, embodiments of the present disclosure provide a communication solution for MT-SDT to overcome the above and other potential problems. Hereinafter, the principles and embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0042] Example of communication environment FIG. 1A is a schematic diagram illustrating an exemplary communication network 100 in which an embodiment of the present disclosure can be implemented. As shown in FIG. 1A, the communication network 100 may include a terminal device 110 and a plurality of network devices. For illustration purposes, a network device 120 and another network device 130 are shown as a plurality of network devices. The network devices 120 and 130 provide respective cells 121 and 131 to serve the terminal device. In the example of FIG. 1A, the terminal device 110 is in the cell 121 of the network device 120, and the terminal device 110 may communicate with the network device 120. The cell 121 may be referred to as a serving cell of the terminal device 110.

[0043] In the context of this application, it is assumed that the network device 130 is the last serving network device for the terminal device 110. In other words, the network device 130 instructs the terminal device 110 to enter an inactive state. The last serving network device maintains the context of the terminal device 110 and the NG connection with the serving authentication management function (AMF) and user plane function (UPF) in a core network (CN) (not shown). The network device 120 is a neighboring network device of the network device 130, and the cell 121 of the network device 120 is included in the RAN-based notification area (RNA) of the terminal device 110. The RNA of the terminal device 110 is configured by the last serving network device, i.e., the network device 130. The RNA may cover a single cell or multiple cells, may be included in a CN registration area, and may utilize Xn connectivity in the RNA. The terminal device 110 may move in the RNA without notifying the network.

[0044] It should be understood that the number of devices in FIG. 1A is given for illustrative purposes and does not imply any limitations to the present disclosure. Communications network 100 may include any suitable number of network devices and / or terminal devices suitable for implementing embodiments of the present disclosure. Furthermore, each of network devices 120 and 130 may provide more cells to terminal device 110.

[0045] 1A, terminal device 110 may communicate with network devices 120 and 130 via channels, such as wireless communication channels. Communications in communication network 100 may conform to any suitable standard, including, but not limited to, Global System for Mobile Communications (GSM), Long Term Evolution (LTE), LTE-Evolution, LTE-Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA), Code Division Multiple Access (CDMA), GSM EDGE Radio Access Network (GERAN), Machine Type Communication (MTC), and the like. Furthermore, communications may be performed according to any generation of communication protocols now known or developed in the future. Examples of communication protocols include, but are not limited to, first generation (1G), second generation (2G), 2.5G, 2.75G, third generation (3G), fourth generation (4G), 4.5G, and fifth generation (5G) communication protocols.

[0046] Communications in the direction from terminal device 110 to network device 120 or 130 are referred to as UL communications, and communications in the direction from network device 120 or 130 to terminal device 110 are referred to as DL communications. Terminal device 110 may move between cells of network device 120 or 130, and possibly other network devices. In UL communications, terminal device 110 may transmit UL data and control information to network device 120 or 130 over a UL channel. In DL communications, network device 120 or 130 may transmit DL data and control information to terminal device 110 over a DL channel.

[0047] Communications in the communication network 100 may be performed according to the UP and CP protocol stacks. Generally speaking, for a communication device (e.g., a terminal device or a network device), there may be multiple entities of multiple network protocol layers in the protocol stack, and these entities may be configured to perform corresponding processes on data or signaling sent from and received by the communication device. Figure 1B is a schematic diagram 100B illustrating network protocol layer entities that may be established for a UP protocol stack in a device according to some embodiments of the present disclosure.

[0048] As shown in FIG. 1B, in the UP, each of the terminal device 110, the network device 120, and the network device 130 may include an L1 layer entity, i.e., a physical (PHY) layer entity (also referred to as a PHY entity), and one or more entities of upper layers (L2 layer and L3 layer, i.e., upper layers), including a medium access control (MAC) layer entity (also referred to as a MAC entity), a radio link control (RLC) layer entity (also referred to as an RLC entity), a packet data convergence protocol (PDCP) layer entity (also referred to as a PDCP entity), and a service data application protocol (SDAP) layer entity (also referred to as an SDAP entity, which is established in 5G and subsequent generation networks). In some cases, the PHY, MAC, RLC, PDCP, and SDAP entities are in a stack structure.

[0049] FIG. 1C is a schematic diagram 100C illustrating network protocol layer entities that may be established for a CP protocol stack in an apparatus according to some embodiments of the present disclosure. As shown in FIG. 1C, in a CP, each of the terminal device 110, the network device 120, and the network device 130 may include one or more entities of higher layers (L2 layer and L3 layer), including an L1 layer entity, i.e., a PHY layer entity (also referred to as a PHY entity), a MAC layer entity (also referred to as a MAC entity), an RLC layer entity (also referred to as an RLC entity), a PDCP layer entity (also referred to as a PDCP entity), and a radio resource control (RRC) layer entity (also referred to as an RRC entity). The RRC layer may further be referred to as an access stratum (AS) layer, and therefore the RRC entity may further be referred to as an AS entity. As shown in FIG. 1C, the terminal device 110 may further include a non-access stratum (NAS) layer entity (also referred to as a NAS entity). The NAS layer on the network side is located in a core network (CN, not shown) rather than in a network device. In some cases, these entities are stacked.

[0050] Generally, communication channels are divided into logical channels, transmission channels, and physical channels. Physical channels are channels through which the PHY layer actually transmits information. For example, physical channels may include a physical uplink control channel (PUCCH), a physical uplink shared channel (PUSCH), a physical random-access channel (PRACH), a physical downlink control channel (PDCCH), a physical downlink shared channel (PDSCH), and a physical broadcast channel (PBCH).

[0051] The transmission channel is a channel between the PHY layer and the MAC layer. For example, the transmission channel may include a broadcast channel (BCH), a downlink shared channel (DL-SCH), a paging channel (PCH), an uplink shared channel (UL-SCH), and a random access channel (RACH).

[0052] A logical channel is a channel between the MAC layer and the RLC layer. For example, the logical channel may include a dedicated control channel (DCCH), a common control channel (CCCH), a paging control channel (PCCH), a broadcast control channel (BCCH), and a dedicated traffic channel (DTCH).

[0053] Generally, a channel between the RRC layer and the PDCP layer is referred to as a radio bearer. The terminal device 110 may be configured to have at least one data radio bearer (DRB) for carrying data plane data and at least one signaling radio bearer (SRB) for carrying control plane data. In the context of the present disclosure, the DRB may be configured to support transmission in an inactive state (i.e., to support SDT). Of course, the DRB may be configured not to support transmission in an inactive state. The SRB may be configured to support transmission in an inactive state. Of course, the SRB may be configured not to support transmission in an inactive state.

[0054] In the RRC layer, three types of SRBs are defined: SRB0, SRB1 and SRB2. SRB0 uses CCCH to establish or re-establish an RRC connection. SRB1 uses DCCH and is established when an RRC connection is established. SRB2 uses DCCH and is established during RRC re-configuration and after the first security activation.

[0055] Furthermore, a protocol data unit (PDU) session may be established in the NAS layer of the terminal device 110 to transmit data to the CN and receive data from the CN. The PDU session may correspond to an SDAP entity and may include multiple quality of service (QoS) flows. In the context of the present disclosure, the QoS flow may be configured to support transmission in an inactive state. Of course, the QoS flow may be configured not to support transmission in an inactive state.

[0056] In some scenarios, when the terminal device 110 is in an inactive state, when the network device 130 as the last serving network device receives DL data from the UPF or receives DL signaling associated with the terminal device 110 (except for a UE context release command message) from the AMF, the network device 130 may page in a cell corresponding to the RNA. This procedure may be referred to as RAN paging. During RAN paging, if the RNA includes cells of one or more neighboring network devices, the network device 130 may send an XnAP RAN paging message to the one or more neighboring network devices.

[0057] 2A is a schematic diagram illustrating a RAN paging procedure 200A in which some embodiments of the present disclosure can be implemented. For illustrative purposes, the process 200A will be described with reference to FIG 1. The process 200A may involve the terminal device 110, the network device 120, and the network device 130 as shown in FIG 1.

[0058] As shown in FIG. 2A, the terminal device 110 is in an inactive state. The network device 130 may determine whether a RAN paging trigger event occurs (201). For example, when the network device 130 receives DL data from the UPF or receives DL signaling associated with the terminal device 110 from the AMF (excluding a UE context release command message), the network device 130 may determine that a RAN paging trigger event occurs. Of course, the RAN paging trigger event is not limited to this example and may be in any other suitable form.

[0059] When it is determined that a RAN paging trigger event occurs, the network device 130 may page in the cell corresponding to the RNA. For convenience, it is determined that the network device 120 is in the cell corresponding to the RNA, and the following description is given by taking the network device 120 as an example. In this case, the network device 130 may transmit an XnAP RAN paging message to the network device 120 and other network devices in the RNA (202). The network device 130 may also transmit a paging message to the terminal device 110 (202').

[0060] Upon receiving the XnAP RAN paging message, the network device 120 may transmit (203) a paging message to the terminal device 110. In some embodiments, the paging message may include an inactive radio network temporary identifier (I-RNTI). Of course, the paging message may also include any other suitable information. If successfully reached at the terminal device 110, the terminal device 110 may attempt to resume (204) from an inactive state. Up to this point, the RAN paging procedure is completed. It should be understood that the RAN paging procedure 200A may include more or less steps and is not limited to the above example.

[0061] In some scenarios, when the terminal device 110 in an inactive state has a small amount of infrequent data traffic to transmit, the terminal device 110 may initiate an SDT procedure, i.e., MO-SDT. As mentioned above, SDT is a procedure that allows data communication while remaining in an inactive state (i.e., without transitioning to a connected state). In some embodiments, SDT is enabled on a radio bearer basis and is initiated by the terminal device only when it waits for less than a configured amount of UL data to be transmitted across all SDT-enabled radio bearers and the measured reference signal received power (RSRP) in the cell is above a configured threshold.

[0062] 2B is a schematic diagram illustrating a one-time SDT procedure 200B in which some embodiments of the present disclosure can be implemented. For illustrative purposes, the process 200B is described with reference to FIG. 1. The process 200B may involve a terminal device 110 and a network device 120 serving the terminal device 110 as shown in FIG. 1. It should be understood that this is only one example and that the process 200B may also be performed between the terminal device 110 and the network device 130.

[0063] As shown in FIG. 2B, the terminal device 110 in the inactive state may transmit an RRC resume request together with UL data associated with data traffic to the network device 120 (211). For example, the terminal device 110 may transmit the RRC resume request together with the UL data in MsgA of the two-step RACH procedure or Msg3 of the four-step RACH procedure. Of course, the terminal device 110 may also transmit the RRC resume request together with the UL data in a configuration grant (CG) resource. Upon receiving the RRC resume request and the UL data, the network device 120 may transmit an RRC release message together with DL data corresponding to the UL data to the terminal device 110 (212). For example, the network device 120 may transmit an RRC release message together with DL data in Msg B of the two-step RACH procedure or Msg4 of the four-step RACH procedure. The network device 120 may also transmit an RRC release message together with DL data in response to the transmission in the CG resource. At this point, the SDT procedure 200B ends.

[0064] FIG. 2C is a schematic diagram illustrating an SDT procedure 200C including an initial transmission and subsequent transmissions, in which some embodiments of the present disclosure can be implemented. As shown in FIG. 2C, the terminal device 110 in an inactive state may transmit an RRC resume request together with UL data and a BSR to the network device 120 (221). For example, the terminal device 110 may transmit the RRC resume request together with the UL data and a BSR in MsgA of a two-step RACH procedure or Msg3 of a four-step RACH procedure. Of course, the terminal device 110 may also transmit the RRC resume request together with the UL data in a configuration grant (CG) resource. The RRC resume request may include a resume cause. Upon receiving the RRC resume request together with the UL data and a BSR, the network device 120 may transmit an indication of a subsequent transmission to the terminal device 110 (222). For example, the network device 120 may transmit an explicit RRC message indicating a subsequent transmission. As another example, the network device 120 may transmit a UL grant for another transmission, implicitly indicating a subsequent transmission. In some embodiments, the network device 120 may transmit DL data with an indication to the terminal device 110. At this point, the first transmission is complete.

[0065] Based on this indication, the terminal device 110 may transmit another UL data and a BSR to the network device 120 (223), for example, based on a dynamic or configured authorization. The network device 120 may then transmit a UL authorization for the dynamic authorization to the terminal device 110 (224). In some embodiments, the network device 120 may transmit DL data to the terminal device 110 along with the UL authorization. Based on the UL authorization from the network device 120, the terminal device 110 may transmit the remaining UL data to the network device 120 (225). Thus, the network device 120 may transmit an RRC release message to the terminal device 110 (226). At this point, the subsequent transmission is complete; that is, the SDT procedure 200C ends. It should be understood that the SDT procedure 200C may include more or fewer steps in the subsequent transmission.

[0066] Example of implementation of MT-SDT procedure decision The embodiments of the present disclosure provide a solution for determining and performing MT-SDT procedures, which will be described in detail below with reference to Figures 3 to 7C.

[0067] FIG. 3 is a schematic diagram of a communication process 300 for MT-SDT according to an embodiment of the present disclosure. For illustrative purposes, the process 300 will be described with reference to FIG. 1. The process 300 may involve a terminal device 110, a network device 120, and a network device 130 as shown in FIG. 1. Assume that the network device 120 is the current (i.e., serving cell) serving network device for the terminal device 110, the network device 130 is the last serving network device for the terminal device 110, and the terminal device 110 has already entered an inactive state under the instruction of the last (i.e., serving cell) serving network device. Further assume that the network device 130 initiates RAN paging in a cell corresponding to RNA, and the network device 120 receives RAN paging from the network device 130. Assume that the terminal device 110 is in a cell 121.

[0068] 3, network device 120 transmits a paging message to terminal device 110 including an indication (for convenience, also referred to herein as a first indication) indicating that MT-SDT is to be performed for terminal device 110 (310). Network device 130 may also transmit the paging message to terminal device 110 (310′). For example, the RAN paging may include information regarding the MT-SDT for terminal device 110. Upon receiving the RAN paging, network device 120 may transmit the first indication to terminal device 110 in the paging message. It should be understood that the transmission of the first indication may be triggered by any other suitable triggering event, and the disclosure is not limited in this respect.

[0069] Because the terminal device 110 is in the cell 121, the terminal device 110 may only respond to the paging message from the network device 120. Upon receiving the paging message from the network device 120, the terminal device 110 determines (320) whether RA-based MT-SDT or CG-based MT-SDT is performed for the terminal device 110. For RA-based MT-SDT, the initial UL transmission of the MT-SDT is transmitted in Msg 3 or Msg A. For CG-based MT-SDT, the initial UL transmission of the MT-SDT is transmitted in CG resources.

[0070] In some embodiments, upon receiving a paging message indicating MT-SDT, the RRC layer of terminal device 110 may determine that an MT-SDT procedure has been triggered, the RRC layer of terminal device 110 may indicate to the MAC layer of terminal device 110 that MT-SDT has been triggered, and the MAC layer may determine whether RA-based MT-SDT or CG-based MT-SDT has been performed for terminal device 110. In some embodiments, the MAC layer may skip the serving cell RSRP check and / or data volume check for MT-SDT and perform a selection between RA-based MT-SDT and CG-based MT-SDT.

[0071] In some embodiments, the terminal device 110 may perform the decision 320 based on at least one of information of CG resources configured for SDT, information of RA resources configured for SDT, information of CG resources dedicated to MT-SDT, or information of RA resources dedicated to MT-SDT. In some embodiments, the terminal device 110 may receive from the network device 120 one or more configurations indicating at least one of information of CG resources configured for SDT, information of RA resources configured for SDT, information of CG resources dedicated to MT-SDT, or information of RA resources dedicated to MT-SDT.

[0072] In some embodiments, the CG-based MT-SDT may have a higher priority than the RA-based MT-SDT. In these embodiments, the terminal device 110 may determine whether CG resources are available for the SDT, i.e., whether there are valid CG resources. If there are available CG resources in the SDT, the terminal device 110 may determine that the CG-based MT-SDT has been performed. If there are no available CG resources in the SDT, the terminal device 110 may determine that the RA-based MT-SDT has been performed.

[0073] For illustrative purposes, several exemplary embodiments for determining 320 are described in detail below in relation to embodiments 1 to 7.

[0074] EMBODIMENT 1 Since the current CG-SDT setting is designed for MO-SDT, the period of the CG-SDT setting is long considering the service requirements. If the CG-SDT setting is used to transmit the initial UL transmission of the MT-SDT, it may introduce a large delay. Furthermore, if the terminal device does not respond to the RAN paging message for a long time, the network device pages the terminal device in a wider area, and thus initiates a core network (CN) paging. In view of this, embodiment 1 provides a solution for determining the MT-SDT to solve the above and other potential problems. This embodiment will be described with reference to FIG. 4A and FIG. 4B.

[0075] 4A is a flowchart illustrating an example process 400A for determining an MT-SDT procedure according to the first embodiment of the present disclosure. For example, the method 400A may be performed in a terminal device 110 as shown in FIG. 1. For illustrative purposes, the method 400A will be described below with reference to FIG. 1. It should be understood that the method 400A may include additional blocks not shown and / or omit some blocks shown, and that the scope of the present disclosure is not limited in this respect.

[0076] As shown in FIG. 4A, in block 410, the terminal device 110 may determine a time interval (also referred to herein as a first time interval for convenience) between the time of the trigger of the MT-SDT (i.e., the time of receipt of the paging message) and the time of the next CG resource available for the SDT. FIG. 4B is a schematic diagram 400B illustrating an example determination of the first time interval according to the process of FIG. 4A. As shown in FIG. 4B, starting from the trigger of the MT-SDT, the next CG resource available for the SDT is on the CG opportunity 401. Then, a time interval 402 from the trigger of the MT-SDT to the CG opportunity 401 may be determined.

[0077] Returning to FIG. 4A, in block 420, terminal device 110 may determine whether the first time interval is less than or equal to the first threshold interval. In some embodiments, terminal device 110 may receive a configuration (also referred to herein as a first configuration for convenience) from network device 120 indicating the first threshold interval. For example, terminal device 110 may receive the first configuration in system information from network device 120. As another example, terminal device 110 may receive the first configuration in an RRC message (e.g., an RRC release message or any other suitable message) from network device 120. Of course, any other suitable manner is also possible.

[0078] If the first time interval is less than or equal to the first threshold interval, the process 400A proceeds to block 430. In block 430, the terminal device 110 may determine that a CG-based MT-SDT has been performed.

[0079] If the first time interval is greater than the first threshold interval, the process 400A proceeds to block 440. In block 440, the terminal device 110 may determine that the RA-based MT-SDT has been performed. In some embodiments in which the RA-based MT-SDT is performed, the terminal device 110 may store information regarding the CG-based MT-SDT that has not been performed for the terminal device 110 and notify the network device 120 of the stored information. In some embodiments, the stored information may include that the first time interval is greater than the first threshold interval, i.e., the cause of the long delay. In some embodiments, the stored information may include the length of the first time interval, i.e., the actual delay.

[0080] The solution of embodiment 1 makes it possible to guarantee the delay of CG-based MT-SDT.

[0081] EMBODIMENT 2 This embodiment is an alternative to embodiment 1. This embodiment will be described with reference to Figures 5A and 5B.

[0082] 5A is a flowchart illustrating an example process 500A for determining an MT-SDT procedure according to a second embodiment of the present disclosure. For example, the method 500A may be performed in a terminal device 110 as shown in FIG. 1. For illustrative purposes, the method 500A will be described below with reference to FIG. 1. It should be understood that the method 500A may include additional blocks not shown and / or omit some blocks that are shown, and that the scope of the present disclosure is not limited in this respect.

[0083] 5A, in block 510, the terminal device 110 may determine a first time interval between the time of the trigger of the MT-SDT (i.e., the time of receipt of the paging message) and the time of the next CG resource available for the SDT. For example, the next CG resource may be the next available CG opportunity.

[0084] In block 520, the terminal device 110 may determine a time interval (also referred to herein as a second time interval for convenience) between the time of the trigger of the MT-SDT (i.e., the time of receipt of the paging message) and the time of the next RA resource available for the SDT. For example, the next RA resource may be the next available PRACH opportunity or the next PUSCH resource available for the two-step RACH.

[0085] 5B is a schematic diagram 500B illustrating an example determination of the first time interval and the second time interval according to the process of FIG. 5A. As shown in FIG. 5B, starting from the trigger of MT-SDT, the next CG resource available for SDT is on a CG opportunity 501. Then, a time interval 502 from the trigger of MT-SDT to the CG opportunity 501 may be determined. Starting from the trigger of MT-SDT, the next RA resource available for SDT is on a PRACH opportunity or a PUSCH opportunity 503. Then, a time interval 504 from the trigger of MT-SDT to the PRACH opportunity or a PUSCH opportunity 503 may also be determined.

[0086] 5A, in block 530, the terminal device 110 may determine whether the first time interval is less than or equal to the second time interval. If the first time interval is less than or equal to the second time interval, the process 500A proceeds to block 540. In block 540, the terminal device 110 may determine that the CG-based MT-SDT has been performed.

[0087] If the first time interval is greater than the second time interval, process 500A proceeds to block 550. In block 550, terminal device 110 may determine that RA-based MT-SDT has been performed.

[0088] The solution of embodiment 2 also makes it possible to guarantee the delay of CG-based MT-SDT. Furthermore, since there is no need to set the first threshold interval, it is possible to reduce signaling overhead.

[0089] EMBODIMENT 3 At present, it is unclear whether RA settings for SDT or RA settings for non-SDT or both can be used for MT-SDT. For RA-based MT-SDT, the following possibilities exist: First, only RA settings for non-SDT can be used for RA-based MT-SDT. Second, only RA settings for SDT can be used for RA-based MT-SDT. Third, both RA settings for non-SDT and RA settings for SDT can be used for RA-based MT-SDT.

[0090] In the context of the present disclosure, an RA configuration may include RA resources and parameters used for an RA procedure. The RA resources may include a preamble, a PRACH opportunity, and / or a PUSCH opportunity. An RA configuration for SDT refers to an RA configuration used for an SDT procedure. An RA configuration for non-SDT refers to an RA configuration not used for an SDT procedure.

[0091] If the RA setting for SDT is used for MT-SDT, it may cause a long delay. The delay is longer than when using the RA setting for non-SDT. In view of this, embodiment 3 provides a solution for determining MT-SDT to solve the above and other potential problems. In this solution, it is assumed that both the RA setting for non-SDT and the RA setting for SDT are available for RA-based MT-SDT. This embodiment will be described with reference to FIG. 6A.

[0092] 6A is a flowchart illustrating an example process 600A for determining an MT-SDT procedure according to a third embodiment of the present disclosure. For example, the method 600A may be performed in the terminal device 110 as shown in FIG. 1. Hereinafter, the method 600A will be described with reference to FIG. 1 for illustrative purposes. It should be understood that the method 600A may include additional blocks not shown and / or omit some blocks shown, and the scope of the present disclosure is not limited in this respect. Assume that RA-based MT-SDT is determined to be performed for the terminal device 110.

[0093] 6A, in block 610, the terminal device 110 may determine a time interval (also referred to herein as a third time interval for convenience) between the time of the trigger of the MT-SDT (i.e., the time of receipt of the paging message) and the time of the next RA resource available for the SDT. For example, the next RA resource available for the SDT may be the next available PRACH opportunity or the next available PUSCH opportunity.

[0094] In block 611, the terminal device 110 may determine whether the third time interval is less than or equal to the second threshold interval. In some embodiments, the terminal device 110 may receive a configuration (also referred to herein as a second configuration for convenience) from the network device 120 indicating the second threshold interval. For example, the terminal device 110 may receive the second configuration in system information from the network device 120. As another example, the terminal device 110 may receive the second configuration in an RRC message (e.g., an RRC release message or any other suitable message) from the network device 120. Of course, any other suitable manner is also possible.

[0095] If the third time interval is less than or equal to the second threshold interval, the process 600A proceeds to block 612. In block 612, the terminal device 110 may perform RA-based MT-SDT based on an RA configuration for SDT (also referred to as a first RA configuration in this specification for convenience).

[0096] If the first time interval is greater than the first threshold interval, the process 600A proceeds to block 613. In block 613, the terminal device 110 may perform RA-based MT-SDT based on an RA configuration for non-SDT (for convenience, also referred to as a second RA configuration in this specification).

[0097] The solution of embodiment 3 makes it possible to guarantee the delay of RA-based MT-SDT.

[0098] EMBODIMENT 4 This embodiment is an alternative to embodiment 3. This embodiment will be described with reference to Figure 6B.

[0099] FIG. 6B is a flowchart illustrating an example process 600B for determining an MT-SDT procedure according to the fourth embodiment of the present disclosure. For example, the method 600B may be performed in the terminal device 110 as shown in FIG. 1. Hereinafter, the method 600B will be described with reference to FIG. 1 for illustrative purposes. It should be understood that the method 600B may include additional blocks not shown and / or omit some blocks shown, and the scope of the present disclosure is not limited in this respect. Assume that RA-based MT-SDT is determined to be performed for the terminal device 110.

[0100] 6B, in block 620, the terminal device 110 may determine a third time interval between the time of the trigger of the MT-SDT and the time of the next RA resource available for the SDT. For example, the next RA resource available for the SDT may be the next available PRACH opportunity or the next available PUSCH resource.

[0101] In block 621, the terminal device 110 may determine a time interval between the time of the trigger of the MT-SDT and the time of the next random access resource available for non-SDT (for convenience, also referred to herein as the fourth time interval).

[0102] In block 622, the terminal device 110 may determine whether the third time interval is less than or equal to the fourth time interval. If the third time interval is less than or equal to the fourth time interval, the process 600B proceeds to block 623. In block 623, the terminal device 110 may perform RA-based MT-SDT based on the first RA configuration for SDT.

[0103] If the first time interval is greater than the first threshold interval, process 600B proceeds to block 624. In block 624, terminal device 110 may perform RA-based MT-SDT based on the second RA configuration for non-SDT.

[0104] The solution of embodiment 4 also makes it possible to guarantee the delay of RA-based MT-SDT. Furthermore, since there is no need to set the second threshold interval, it is possible to reduce signaling overhead.

[0105] EMBODIMENT 5 Currently, the size of the configured CG resource is usually designed for MO-SDT, so it has a large UL grant size. Although the UL grant size of the CG resource may be several thousand bits, only 100 bits are enough for the initial UL transmission of MT-SDT. Therefore, many padding bits need to be inserted, which may also cause a waste of UL grant, so the configured CG resource may not be suitable for MT-SDT.

[0106] In view of this, embodiment 5 provides a solution for determining MT-SDT to solve the above and other potential problems, which will be described with reference to FIG. 7A.

[0107] 7A is a flowchart illustrating an example process 700A for determining an MT-SDT procedure according to a fifth embodiment of the present disclosure. For example, the method 700A may be performed in a terminal device 110 as shown in FIG. 1. For illustrative purposes, the method 700A will be described below with reference to FIG. 1. It should be understood that the method 700A may include additional blocks not shown and / or omit some blocks that are shown, and that the scope of the present disclosure is not limited in this respect.

[0108] As shown in Figure 7A, in block 710, terminal device 110 may determine whether CG resources dedicated to MT-SDT are available. In some embodiments, the CG resources dedicated to MT-SDT may have a smaller UL grant and / or a shorter delay than the CG resources configured for MO-SDT. In some embodiments, terminal device 110 may receive a configuration (also referred to herein as a third configuration for convenience) from network device 120 indicating the CG resources dedicated to MT-SDT.

[0109] If dedicated CG resources are available for MT-SDT, process 700A proceeds to block 711. In block 711, terminal device 110 may determine that CG-based MT-SDT has been performed for terminal device 110.

[0110] If there are no dedicated CG resources for MT-SDT available, process 700A proceeds to block 712. In block 712, terminal device 110 may determine that RA-based MT-SDT is performed for terminal device 110.

[0111] The solution of embodiment 5 can avoid the waste of UL permission and improve the probability of successful transmission.

[0112] EMBODIMENT 6 This embodiment is an alternative to embodiment 5. This embodiment will be described with reference to Figure 7B.

[0113] FIG. 7B is a flowchart illustrating an example process 700B for determining an MT-SDT procedure according to a sixth embodiment of the present disclosure. For example, the method 700B may be performed in the terminal device 110 as shown in FIG. 1. Hereinafter, the method 700B will be described with reference to FIG. 1 for illustrative purposes. It should be understood that the method 700B may include additional blocks not shown and / or omit some blocks shown, and the scope of the present disclosure is not limited in this respect. Assume that a CG-based MT-SDT is determined to be performed for the terminal device 110.

[0114] 7B, in block 720, the terminal device 110 may determine a transmission configuration from a set of transmission configurations for CG-based MT-SDT. In some embodiments, the transmission configuration may include at least one of a modulation order, a target code rate, or a transport block (TB) size. For example, the transmission configuration may be a TBSandMCS configuration or any other suitable form.

[0115] In some embodiments, the terminal device 110 may receive the set of transmission configurations from the network device 120 in an RRC release message. The terminal device 110 may select an appropriate one of the transmission configurations from the set of transmission configurations when triggering the CG-based MT-SDT. For example, the terminal device 110 may perform the selection based on the size of data of the initial UL transmission of the MT-SDT. Of course, any other suitable method for the selection is also possible. In some embodiments in which the set of transmission configurations includes a single transmission configuration for the MT-SDT, the terminal device 110 may use the single transmission configuration for the CG-based MT-SDT.

[0116] In block 721, the terminal device 110 may perform the CG-based MT-SDT based on the determined transmission configuration. In some embodiments, the terminal device 110 may indicate the determined transmission configuration to the network device 120 by UCI piggybacked on the initial UL transmission of the CG-based MT-SDT.

[0117] The solution of embodiment 6 can also avoid the waste of UL permission and improve the probability of successful transmission.

[0118] EMBODIMENT 7 This embodiment is also an alternative to embodiment 5. This embodiment will be described with reference to Figure 7C.

[0119] 7C is a flowchart illustrating an example process 700C for determining an MT-SDT procedure according to the seventh embodiment of the present disclosure. For example, the method 700C may be performed in the terminal device 110 as shown in FIG. 1. Hereinafter, the method 700C will be described with reference to FIG. 1 for illustrative purposes. It should be understood that the method 700C may include additional blocks not shown and / or omit some blocks shown, and the scope of the present disclosure is not limited in this respect. Assume that RA-based MT-SDT is determined to be performed for the terminal device 110.

[0120] As shown in FIG. 7C, in block 730, terminal device 110 may determine whether RA resources dedicated to MT-SDT are available. In some embodiments, the RA resources dedicated to MT-SDT may have a smaller UL grant and / or a shorter delay than the RA resources configured for MO-SDT. In some embodiments, terminal device 110 may receive a configuration (also referred to herein as a fourth configuration for convenience) from network device 120 indicating the RA resources dedicated to MT-SDT.

[0121] If RA resources dedicated to MT-SDT are available, process 700C proceeds to block 731. In block 731, terminal device 110 may determine that RA-based MT-SDT has been performed for terminal device 110. That is, terminal device 110 may select only RA resources dedicated to MT-SDT. In some embodiments, if there are no RA resources dedicated to MT-SDT available, terminal device 110 may determine that MO-SDT or non-SDT procedures have been performed for terminal device 110.

[0122] The solution of embodiment 7 can also avoid the waste of UL permission and improve the probability of successful transmission.

[0123] So far, some exemplary embodiments of the MT-SDT procedure decision 320 have been described. Returning to FIG. 3, based on the decision 320, the terminal device 110 performs the MT-SDT procedure via RA or CG resources (330). In some embodiments, if the terminal device 110 determines that RA-based MT-SDT has been performed, the terminal device 110 may perform the initial UL transmission of MT-SDT via RA resources. If the terminal device 110 determines that CG-based MT-SDT has been performed, the terminal device 110 may perform the initial UL transmission of MT-SDT via CG resources.

[0124] In some embodiments, the terminal device 110 may perform the initial UL transmission by sending an RRC Resume Request message to the network device 120. In some embodiments, the RRC Resume Request message may include an indication (for convenience, also referred to herein as the second indication) indicating the MT-SDT. In some alternative embodiments, the RRC Resume Request message may not include the second indication.

[0125] In some scenarios, when the terminal device 110 goes into an inactive state after receiving an RRC release message in a suspended configuration, there may be UL packets (i.e., buffered data) buffered in the terminal device 110 that were not successfully transmitted to the network device 120. This raises the question of whether the buffered data is transmitted with the initial UL transmission of the MT-SDT.

[0126] In some embodiments, upon triggering of the MT-SDT, the terminal device 110 may resume radio bearers configured to have the SDT and perform PDCP re-establishment and RLC re-establishment for the PDCP and RLC entities of the radio bearers configured to have the SDT so that the buffered data is transmitted together with the initial UL transmission of the MT-SDT. In some embodiments, the terminal device 110 may allocate UL resources for an SRB (e.g., SRB0) for the initial UL transmission by the MAC layer of the terminal device 110 (331). In other words, the terminal device 110 may not allocate UL resources for radio bearers other than SRB0 for the initial UL transmission of the MT-SDT. In these embodiments, the terminal device 110 may allocate resources for radio bearers other than SRB0 for subsequent transmission of the MT-SDT by the MAC layer. These radio bearers are configured to have the SDT and are not suspended.

[0127] In some alternative embodiments, terminal device 110 may determine whether the execution of the initial uplink transmission was successful (332). If the execution of the initial uplink transmission was successful, terminal device 110 may resume (333) the set of radio bearers configured to have the SDT and perform PDCP re-establishment and RLC re-establishment for the PDCP and RLC entities of the set of radio bearers. For example, after the MAC layer indicates successful completion of the RA procedure for the MT-SDT or after the MAC layer indicates successful CG transmission, terminal device 110 may resume the set of radio bearers configured to have the SDT and perform PDCP re-establishment and RLC re-establishment for the PDCP and RLC entities of the set of radio bearers.

[0128] Thus, in the initial UL transmission of the MT-SDT, no buffered data is transmitted, so that bits of data to be transmitted may be preserved, making it easier for the terminal device 110 to successfully resume the RRC connection with the network device 120.

[0129] Alternatively, the buffered data may be transmitted together with the initial UL transmission of the MT-SDT. In these embodiments, the terminal device 110 may allocate resources for SRB0 and other (configured to have an SDT and not suspended) radio bearers by the MAC layer for the initial UL transmission of the MT-SDT. The terminal device 110 may also allocate resources for (configured to have an SDT and not suspended) radio bearers by the MAC layer during subsequent transmissions of the MT-SDT. Thus, the buffered data may be transmitted together with the initial UL transmission of the MT-SDT.

[0130] 3, upon receiving the initial UL transmission, the network device 120 may send a request to the network device 130 to retrieve the context of the terminal device 110 (335). The request includes an indication (also referred to herein as a third indication for convenience) indicating that MT-SDT has been performed for the terminal device 110. For example, the network device 120 may send the request in a retrieve UE context request message. Of course, any other suitable manner is also possible.

[0131] Based on the presence or absence of the third indication, network device 130 may recognize whether the request is for MT-SDT purposes and may determine whether to perform anchor location. In some embodiments, network device 130 may send (335') the context of terminal device 110 to network device 120.

[0132] Upon receiving an RRC RESUME REQUEST message indicating an initial UL transmission, e.g., MT-SDT, network device 120 may respond to terminal device 110 in any suitable manner. In some embodiments, network device 120 may send an RRC RELEASE message with DL data to terminal device 110 (340). In some embodiments, network device 120 may send an RRC RESUME message to terminal device 110 (350). In some embodiments, network device 120 may send an RRC REJECT message to terminal device 110 (360). In some embodiments, network device 120 may send an RRC SETUP message to terminal device 110 (370).

[0133] In some embodiments, network device 120 may transmit DL data to terminal device 110 while performing subsequent transmission with terminal device 110 (380). For example, network device 120 may transmit DL data to terminal device 110 (381). Terminal device 110 may transmit UL data to network device 120 (382). Network device 120 may transmit an RRC release message with the DL data to terminal device 110 (383). The MT-SDT procedure then ends.

[0134] Example of the method Therefore, the embodiments of the present disclosure provide communication methods implemented in a terminal device and a network device, which are described below with reference to Figures 8-9.

[0135] 8 illustrates an example communication method 800 implemented in a terminal device, according to some embodiments of the present disclosure. For example, the method 800 may be performed in a terminal device 110 as shown in FIG. For purposes of explanation, the method 800 will be described below with reference to FIG. 1. It should be understood that the method 800 may include additional blocks not shown and / or omit some blocks that are shown, and that the scope of the present disclosure is not limited in this respect.

[0136] In block 810, the terminal device 110 receives a paging message from a network device 120 in the RAN, the paging message including a first indication indicating that MT-SDT is performed for the terminal device 110.

[0137] In block 820, the terminal device 110 determines whether RA-based MT-SDT or CG-based MT-SDT has been performed for the terminal device 110. In some embodiments, the terminal device 110 may indicate to the MAC layer of the terminal device 110 via the RRC layer of the terminal device 110 that an MT-SDT procedure has been triggered, and the MAC layer may determine whether RA-based MT-SDT or CG-based MT-SDT has been performed for the terminal device 110.

[0138] In some embodiments, the terminal device 110 may determine whether CG resources are available for the SDT. If CG resources are available for the SDT, the terminal device 110 may determine that a CG-based MT-SDT has been performed for the terminal device 110. If there are no CG resources available for the SDT, the terminal device 110 may determine that a RA-based MT-SDT has been performed for the terminal device 110.

[0139] In some embodiments, the terminal device 110 may determine a first time interval between the time of the trigger of MT-SDT and the time of the next CG resource available for SDT. If the first time interval is less than or equal to the first threshold interval, the terminal device 110 may determine that a CG-based MT-SDT has been performed for the terminal device 110. If the first time interval is greater than the first threshold interval, the terminal device 110 may determine that an RA-based MT-SDT has been performed for the terminal device 110. In some embodiments, the terminal device 110 may receive a first configuration from the network device 120 indicating the first threshold interval.

[0140] In some embodiments, when the RA-based MT-SDT is performed for the terminal device 110, the terminal device 110 may store information about the CG-based MT-SDT that is not performed for the terminal device 110, and notify the network device 120 of the stored information. In some embodiments, the information may include at least one of: the first time interval is greater than the first threshold interval, or the first time interval.

[0141] In some embodiments, the terminal device 110 may determine a first time interval between the time of triggering the MT-SDT and the time of the next CG resource available for the SDT, and may determine a second time interval between the time of triggering the MT-SDT and the time of the next RA resource available for the SDT. If the first time interval is less than or equal to the second time interval, the terminal device 110 may determine that a CG-based MT-SDT has been performed for the terminal device 110. If the first time interval is greater than the second time interval, the terminal device 110 may determine that a RA-based MT-SDT has been performed for the terminal device 110.

[0142] In some embodiments, if the RA-based MT-SDT is performed for the terminal device 110, the terminal device 110 may determine a third time interval between the time of the trigger of the MT-SDT and the time of the next RA resource available for the SDT. If the third time interval is less than or equal to the second threshold interval, the terminal device 110 may perform the RA-based MT-SDT based on a first RA configuration for the SDT. The first RA configuration may include the next RA resource available for the SDT. If the third time interval is greater than the second threshold interval, the terminal device 110 may perform the RA-based MT-SDT based on a second RA configuration for the non-SDT. In some embodiments, the terminal device 110 may receive from the network device 120 a second configuration indicating the second threshold interval.

[0143] In some embodiments, when the RA-based MT-SDT is executed for the terminal device 110, the terminal device 110 may determine a third time interval between the time of the trigger of the MT-SDT and the time of the next RA resource available for the SDT, and may determine a fourth time interval between the time of the trigger of the MT-SDT and the time of the next RA resource available for the non-SDT. If the third time interval is equal to or less than the fourth time interval, the terminal device 110 may execute the RA-based MT-SDT based on a first RA configuration for the SDT. The first RA configuration may include the next RA resource available for the SDT. If the third time interval is greater than the fourth threshold interval, the terminal device 110 may execute the RA-based MT-SDT based on a second RA configuration for the non-SDT. The second RA configuration may include the next RA resource available for the non-SDT.

[0144] In some embodiments, the terminal device 110 may determine whether a dedicated CG resource is available for MT-SDT. If the dedicated CG resource is available, the terminal device 110 may determine that a CG-based MT-SDT has been performed for the terminal device 110. If no dedicated CG resource is available, the terminal device 110 may determine that an RA-based MT-SDT has been performed for the terminal device 110. In some embodiments, the terminal device 110 may receive a third configuration from the network device 120 indicating the dedicated CG resource.

[0145] In some embodiments, when CG-based MT-SDT is performed for terminal device 110, terminal device 110 may determine a transmission configuration from a set of transmission configurations for CG-based MT-SDT and perform CG-based MT-SDT based on the determined transmission configuration. In some embodiments, the transmission configuration may include at least one of a modulation order, a target code rate, or a TB size. In some embodiments, terminal device 110 may receive the set of transmission configurations from network device 120 in an RRC release message.

[0146] In some embodiments, when RA-based MT-SDT is performed for terminal device 110, terminal device 110 may determine whether dedicated RA resources are available for MT-SDT. If dedicated RA resources are available, terminal device 110 may perform RA-based MT-SDT based on the dedicated RA resources. In some embodiments, terminal device 110 may receive a fourth configuration from network device 120 indicating dedicated RA resources.

[0147] In some embodiments, if RA-based MT-SDT is performed for terminal device 110, terminal device 110 may perform an initial uplink transmission of MT-SDT to network device 120 via RA resources. In some embodiments, if CG-based MT-SDT is performed for terminal device 110, terminal device 110 may perform an initial uplink transmission to network device 120 via CG resources.

[0148] In some embodiments, terminal device 110 may receive an RRC release message along with DL data from network device 120. In some embodiments, terminal device 110 may receive an RRC resume message from network device 120. In some embodiments, terminal device 110 may receive an RRC reject message from network device 120. In some embodiments, terminal device 110 may receive an RRC setup message from network device 120. In some embodiments, terminal device 110 may receive DL data from network device 120 while performing a subsequent transmission with network device 120.

[0149] In some embodiments, terminal device 110 may perform the initial uplink transmission by allocating, via the MAC layer of terminal device 110, UL resources for SRBs for the initial uplink transmission, including the transmission of an RRC Resume Request message. In some embodiments, the RRC Resume Request message includes a second indication of the MT-SDT. In some embodiments, terminal device 110 may also allocate, via the MAC layer, resources for radio bearers other than the SRBs for subsequent transmissions of the MT-SDT.

[0150] In some embodiments, terminal device 110 may determine whether the initial UL transmission was successfully performed, and if the initial UL transmission was successfully performed, terminal device 110 may resume the set of radio bearers configured to have the SDT and perform PDCP and RLC re-establishment for the set of radio bearers.

[0151] 9 illustrates an example communication method 900 implemented in a network device serving a terminal device, according to some embodiments of the present disclosure. For example, the method 900 may be performed in the network device 120 as shown in FIG. 1. For purposes of explanation, the method 900 will be described below with reference to FIG. 1. It should be understood that the method 900 may include additional blocks not shown and / or omit some blocks that are shown, and that the scope of the present disclosure is not limited in this respect.

[0152] In block 910, network device 120 sends a paging message to terminal device 110. The paging message includes a first indication that MT-SDT is to be performed for terminal device 110.

[0153] At block 920, the network device 120 receives an initial UL transmission of the MT-SDT over the RA or CG resources from the terminal device 110. In some embodiments, the network device 120 may receive an RRC resume request message from the terminal device 110 that includes a second indication indicating the MT-SDT.

[0154] In some embodiments, network device 120 may send an RRC release message along with the DL data to terminal device 110. In some embodiments, network device 120 may send an RRC resume message to terminal device 110. In some embodiments, network device 120 may send an RRC reject message to terminal device 110. In some embodiments, network device 120 may send an RRC setup message to terminal device 110. In some embodiments, network device 120 may transmit DL data to terminal device 110 while performing subsequent transmissions with terminal device 110.

[0155] In some embodiments, network device 120 may transmit to terminal device 110 a first configuration indicating a first threshold interval for CG-based MT-SDT determination. In some embodiments, network device 120 may transmit to terminal device 110 a second configuration indicating a second threshold interval for RA-based MT-SDT determination.

[0156] In some embodiments, the network device 120 may receive information from the terminal device 110 regarding the non-performed CG-based MT-SDT for the terminal device 110. In some embodiments, the information may include at least one of: the first time interval being greater than the first threshold interval, or the first time interval.

[0157] In some embodiments, the network device 120 may send a set of transmission configurations for CG-based MT-SDT to the terminal device 110 in an RRC release message. In some embodiments, the transmission configurations may include at least one of a modulation order, a target code rate, or a TB size.

[0158] In some embodiments, the network device 120 may transmit a third configuration to the terminal device 110 indicating CG resources dedicated to the MT-SDT. In some embodiments, the network device 120 may transmit a fourth configuration to the terminal device 110 indicating RA resources dedicated to the MT-SDT.

[0159] In some embodiments, network device 120 may send a request to another network device (e.g., network device 130) to obtain the context of terminal device 110, the request including a third indication indicating that MT-SDT has been performed for terminal device 110.

[0160] Thus, the MT-SDT procedure is performed. The implementation of the method shown in Figures 8 and 9 substantially corresponds to the implementation described in relation to Figures 3 to 7C, so that other details are not repeated in this specification.

[0161] Examples of equipment and devices Fig. 10 is a schematic block diagram of an apparatus 1000 suitable for implementing embodiments of the present disclosure. The apparatus 1000 may be considered as another exemplary implementation of the terminal device 110 or the network device 120 shown in Fig. 1. Thus, the apparatus 1000 may be implemented in the terminal device 110 or the network device 120, or as at least a part thereof.

[0162] As shown, the apparatus 1000 comprises a processor 1010, a memory 1020 connected to the processor 1010, a suitable transmitter (TX) and receiver (RX) 1040 connected to the processor 1010, and a communication interface connected to the TX / RX 1040. The memory 1010 stores at least a portion of a program 1030. The TX / RX 1040 is used for bidirectional communication. The TX / RX 1040 has at least one antenna to facilitate communication, although the access nodes referred to herein may in practice have multiple antennas. The communication interface may represent any interface required for communication with other network elements, such as an X2 / Xn interface for bidirectional communication between eNBs / gNBs, an S1 / NG interface for communication between a Mobility Management Entity (MME) / Access and Mobility Management Function (AMF) / SGW / UPF and an eNB / gNB, an Un interface for communication between an eNB / gNB and a relay node (RN), or a Uu interface for communication between an eNB / gNB and a terminal device.

[0163] The program 1030 is assumed to include program instructions that, when executed by the associated processor 1010, enable the device 1000 to operate according to embodiments of the present disclosure, as described herein with reference to Figures 1-9. The embodiments of the present disclosure may be realized by computer software executable by the processor 1010 of the device 1000, or by hardware, or by a combination of software and hardware. The processor 1010 may be configured to implement various embodiments of the present disclosure. Furthermore, the combination of the processor 1010 and the memory 1020 may form a processing means 1050 suitable for implementing various embodiments of the present disclosure.

[0164] The memory 1020 may be of any type suitable for a local technology network and may be implemented using any suitable data storage technology, such as, by way of non-limiting example, non-transitory computer-readable storage media, semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. Although only one memory 1020 is shown in the device 1000, there may be several physically different memory modules in the device 1000. The processor 1010 may be of any type suitable for a local technology network and may include, by way of non-limiting example, one or more of a general purpose computer, a special purpose computer, a microprocessor, a digital signal processor (DSP) and a multi-core processor architecture based processor. The device 1000 may have multiple processors, for example application specific integrated circuit chips time-slaved to a clock that synchronizes the main processor.

[0165] In some embodiments, a terminal device comprises a circuit configured to receive a paging message from a network device in a radio access network, the paging message including a first indication indicating that MT-SDT is to be performed for the terminal device, and configured to determine whether random access based MT-SDT or configuration grant based MT-SDT is to be performed for the terminal device.

[0166] In some embodiments, the circuitry may be configured to indicate, by a radio resource control layer of the terminal device, to a media access control layer of the terminal device that the MT-SDT has been triggered, and to determine, by the media access control layer, whether the random access based MT-SDT or the configuration grant based MT-SDT has been performed for the terminal device.

[0167] In some embodiments, the circuitry may be configured to determine whether configured grant resources are available for SDT, and in response to a determination that the configured grant resources are available for SDT, determine that the configured grant-based MT-SDT has been performed for the terminal device, and in response to a determination that there are no configured grant resources available for SDT, determine that the random access-based MT-SDT has been performed for the terminal device.

[0168] In some embodiments, the circuitry may be configured to determine a first time interval between a time of triggering the MT-SDT and a time of a next configured grant resource available for SDT, determine that the configured grant-based MT-SDT has been performed for the terminal device in response to determining that the first time interval is less than or equal to a first threshold interval, and determine that the random access-based MT-SDT has been performed for the terminal device in response to determining that the first time interval is greater than the first threshold interval. In some embodiments, the circuitry may be further configured to receive from the network device a first configuration indicating the first threshold interval.

[0169] In some embodiments, the circuitry may be further configured to, in response to determining that the random access based MT-SDT has been performed for the terminal device, store information regarding the configuration grant based MT-SDT not being performed for the terminal device, and report the information to the network device. In some embodiments, the information includes at least one of: the first time interval being greater than the first threshold interval, or the first time interval.

[0170] In some embodiments, the circuitry may be configured to determine a first time interval between a time of triggering the MT-SDT and a time of a next configured grant resource available for SDT, determine a second time interval between a time of triggering the MT-SDT and a time of a next random access resource available for SDT, and in response to a determination that the first time interval is less than or equal to the second time interval, determine that the configured grant-based MT-SDT has been performed for the terminal device, and in response to a determination that the first time interval is greater than the second time interval, determine that the random access-based MT-SDT has been performed for the terminal device.

[0171] In some embodiments, the circuitry may be further configured to, in response to determining that the random access based MT-SDT has been performed for the terminal device, determine a third time interval between a time of triggering the MT-SDT and a time of a next random access resource available for SDT, in response to determining that the third time interval is less than or equal to a second threshold interval, perform the random access based MT-SDT based on a first random access configuration for SDT, and in response to determining that the third time interval is greater than the second threshold interval, perform the random access based MT-SDT based on a second random access configuration for non-SDT. In some embodiments, the circuitry may be further configured to receive from the network device a second configuration indicative of the second threshold interval.

[0172] In some embodiments, the circuitry may be further configured to, in response to a determination that the random access-based MT-SDT has been performed for the terminal device, determine a third time interval between a time of triggering the MT-SDT and a time of a next random access resource available for an SDT, determine a fourth time interval between the time of triggering the MT-SDT and a time of a next random access resource available for a non-SDT, in response to a determination that the third time interval is less than or equal to the fourth time interval, perform the random access-based MT-SDT based on a first random access configuration for an SDT, and in response to a determination that the third time interval is greater than the fourth threshold interval, perform the random access-based MT-SDT based on a second random access configuration for a non-SDT.

[0173] In some embodiments, the circuitry may be configured to determine whether dedicated configuration grant resources are available for MT-SDT, determine that the configuration grant-based MT-SDT has been performed for the terminal device in response to determining that the dedicated configuration grant resources are available, and determine that the random access-based MT-SDT has been performed for the terminal device in response to determining that no dedicated configuration grant resources are available. In some embodiments, the circuitry may be further configured to receive a third configuration from the network device indicating the dedicated configuration grant resources.

[0174] In some embodiments, the circuitry is further configured to, in response to determining that the configuration grant-based MT-SDT has been performed for the terminal device, determine a transmission configuration from a set of transmission configurations for the configuration grant-based MT-SDT and perform the configuration grant-based MT-SDT based on the determined configuration. In some embodiments, the transmission configuration includes at least one of a modulation order, a target code rate, or a transport block size. In some embodiments, the circuitry may be further configured to receive the set of transmission configurations in a radio resource control release message from the network device.

[0175] In some embodiments, the circuitry may be further configured to, in response to determining that the random access based MT-SDT has been performed for the terminal device, determine whether a dedicated random access resource for MT-SDT is available, and in response to determining that the dedicated random access resource is available, perform the random access based MT-SDT based on the dedicated random access resource. In some embodiments, the circuitry may be further configured to receive a fourth configuration from the network device indicating the dedicated random access resource.

[0176] In some embodiments, the circuitry may be further configured to: perform an initial uplink transmission of the MT-SDT to the network device via a random access resource in response to a determination that the random access based MT-SDT has been performed for the terminal device; or perform the initial uplink transmission to the network device via a configured grant resource in response to a determination that the configured grant based MT-SDT has been performed for the terminal device.

[0177] In some embodiments, the circuitry may be further configured to receive a radio resource control release message together with downlink data from the network device, receive a radio resource control resume message from the network device, receive a radio resource control reject message from the network device, receive a radio resource control setup message from the network device, or receive downlink data from the network device while performing a subsequent transmission with the network device.

[0178] In some embodiments, the circuitry may be configured to perform the initial uplink transmission by allocating, by a media access control layer of the terminal device, uplink resources for a signaling radio bearer for the initial uplink transmission including transmission of a radio resource control resume request message. In some embodiments, the radio resource control resume request message includes a second indication indicating the MT-SDT. In some embodiments, the circuitry may be further configured to allocate, by the media access control layer, resources for a radio bearer other than the signaling radio bearer for a subsequent transmission of the MT-SDT.

[0179] In some embodiments, the circuitry may be further configured to determine whether the initial uplink transmission was successfully performed, and in response to determining that the initial uplink transmission was successfully performed, resume a set of radio bearers configured to have an SDT, and perform PDCP and RLC re-establishment for the set of radio bearers.

[0180] In some embodiments, the network device comprises a circuit configured to send a paging message to a terminal device including a first indication indicating that MT-SDT is performed for the terminal device, and to receive an initial uplink transmission of the MT-SDT from the terminal device via a random access resource or a configured grant resource.

[0181] In some embodiments, the circuitry may be configured to receive the initial uplink transmission by receiving a radio resource control resume request message from the terminal device, the radio resource control resume request message including a second indication indicating the MT-SDT.

[0182] In some embodiments, the circuitry may be further configured to send a radio resource control release message together with downlink data to the terminal device, send a radio resource control resume message to the terminal device, send a radio resource control reject message to the terminal device, send a radio resource control setup message to the terminal device, and transmit downlink data to the terminal device while performing subsequent transmissions with the terminal device.

[0183] In some embodiments, the circuitry may be further configured to perform at least one of: sending to the terminal device a first configuration indicating a first threshold interval for configuration grant based MT-SDT determination; or sending to the terminal device a second configuration indicating a second threshold interval for random access based MT-SDT determination.

[0184] In some embodiments, the circuitry may be further configured to receive information from the terminal device regarding the configuration grant-based MT-SDT not being performed for the terminal device, in some embodiments, the information includes at least one of: the first time interval being greater than the first threshold interval, or the first time interval.

[0185] In some embodiments, the circuitry may be further configured to send a set of transmission configurations for configuration grant-based MT-SDT to the terminal device in a radio resource control release message, in some embodiments, the transmission configurations include at least one of a modulation order, a target code rate, or a transport block size.

[0186] In some embodiments, the circuitry may be further configured to perform at least one of: sending to the terminal device a third configuration indicating configuration grant resources dedicated to the MT-SDT; or sending to the terminal device a fourth configuration indicating random access resources dedicated to the MT-SDT.

[0187] In some embodiments, the circuitry may be further configured to send to another network device a request to obtain a context of the terminal device, the request including a third indication indicating that MT-SDT has been performed for the terminal device.

[0188] The term "circuitry" as used herein may refer to a hardware circuit and / or a combination of a hardware circuit and software. For example, a circuit may be a combination of analog and / or digital hardware circuitry and software / firmware. As yet another example, a circuit may be any portion of a hardware processor having software, including a digital signal processor, software, and one or more memories, that cooperate to cause a device, such as a terminal device or a network device, to perform various functions. In yet another example, a circuit may be a hardware circuit and / or a processor, such as a microprocessor or a portion thereof, that requires software / firmware for operation, but the software may not be present if not required for operation. As used herein, the term "circuitry" also includes an implementation of only a hardware circuit or one or more processors, or a portion of a hardware circuit or one or more processors and its (or their) associated software and / or firmware.

[0189] Overall, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic, or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software that may be executed by a controller, microprocessor, or other computing device. Although various aspects of the embodiments of the present disclosure have been illustrated and described using block diagrams, flow charts, or some other pictorial representations, it should be understood that the blocks, devices, systems, techniques, or methods described herein may be implemented, by way of non-limiting examples, in hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing device, or any combination thereof.

[0190] The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer-readable storage medium. The computer program product includes computer-executable instructions, such as instructions included in a program module, that execute in a device on a target real or virtual processor to perform the process or method described above with reference to Figures 1-9. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, etc. that perform particular tasks or implement particular abstract data types. In various embodiments, the functionality of the program modules may be combined or divided among program modules as appropriate. The machine-executable instructions of the program modules may be executed in local or distributed devices. In a distributed device, the program modules may be located in both local and remote storage media.

[0191] Program codes for carrying out the methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, a special purpose computer, or other programmable data processing device, and when executed by the processor or controller, the program code causes the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code may run entirely on the machine, partially on the machine, as a separate software package, partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0192] The above program code may be implemented on a machine-readable medium, which may be any tangible medium that can contain or store a program used by or associated with an instruction execution system, device, or apparatus. The machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. The machine-readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or apparatus, or any suitable combination of the aforementioned media. More specific examples of the machine-readable storage medium may include an electrical connection having one or more wires, a portable computer disk, 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 disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the aforementioned.

[0193] It should be noted that although operations have been described in a particular order, it should not be understood that such operations are required to be performed in the particular order shown, or in any sequential order, or to perform all of the operations described, in order to achieve desired results. In some cases, multitasking and parallel processing may be advantageous. Similarly, although some specific implementation details are included in the above discussion, these should not be construed as limitations on the scope of the disclosure, but rather as descriptions of features that may be specific to certain embodiments. Some features described in the context of individual embodiments may be realized in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may be implemented separately in multiple embodiments or in any suitable subcombination.

[0194] Although the present disclosure has been described in language specific to structural features and / or methodological acts, it should be understood that the present disclosure, as defined in the appended claims, is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. 1. A method of communication comprising: receiving, at a terminal device, from a network device in a radio access network, a paging message including a first indication indicating that a mobile-terminated small data transmission (MT-SDT) is to be performed for the terminal device; determining whether a random access based MT-SDT or a configuration grant based MT-SDT has been performed for the terminal device; The method includes:

2. The determining step comprises: indicating, by a radio resource control layer of the terminal device, to a media access control layer of the terminal device that the MT-SDT has been triggered; determining, by the media access control layer, whether the random access based MT-SDT or the configuration grant based MT-SDT is performed for the terminal device; The method of claim 1 , comprising:

3. The determining step comprises: determining whether a configured grant resource is available for small data transmission (SDT); determining that the configured grant-based MT-SDT has been performed for the terminal device in response to determining that the configured grant resources are available for SDT; determining that the random access based MT-SDT has been performed for the terminal device in response to determining that there are no configured grant resources available for SDT; The method of claim 1 , comprising:

4. The determining step comprises: determining a first time interval between a time of triggering the MT-SDT and a time of the next configured grant resource available for SDT; determining that the configuration grant based MT-SDT has been performed for the terminal device in response to determining that the first time interval is less than or equal to a first threshold interval; determining that the random access based MT-SDT has been performed for the terminal device in response to determining that the first time interval is greater than the first threshold interval; The method of claim 1 , comprising:

5. receiving a first setting from the network device indicating the first threshold interval; The method of claim 4 further comprising:

6. storing information regarding the configuration grant-based MT-SDT not being performed for the terminal device in response to determining that the random access-based MT-SDT has been performed for the terminal device; reporting said information to said network device; The method of claim 4 further comprising:

7. The information is the first time interval is greater than the first threshold interval; or The first time interval The method of claim 6 , comprising at least one of:

8. The determining step comprises: determining a first time interval between a time of triggering the MT-SDT and a time of the next configured grant resource available for SDT; determining a second time interval between the time of the trigger of the MT-SDT and the time of the next random access resource available for SDT; determining that the configuration grant-based MT-SDT has been performed for the terminal device in response to determining that the first time interval is less than or equal to the second time interval; determining that the random access based MT-SDT has been performed for the terminal device in response to determining that the first time interval is greater than the second time interval; The method of claim 1 , comprising:

9. determining a third time interval between a time of triggering the MT-SDT and a time of a next random access resource available for SDT in response to determining that the random access based MT-SDT has been performed for the terminal device; performing the random access based MT-SDT based on a first random access configuration for SDT in response to determining that the third time interval is less than or equal to a second threshold interval; performing the random access based MT-SDT based on a second random access configuration for non-SDT in response to determining that the third time interval is greater than the second threshold interval; The method of claim 1 further comprising:

10. receiving a second setting from the network device indicating the second threshold interval; The method of claim 9 further comprising:

11. determining a third time interval between a time of triggering the MT-SDT and a time of a next random access resource available for SDT in response to determining that the random access based MT-SDT has been performed for the terminal device; determining a fourth time interval between the time of the trigger of the MT-SDT and the time of the next random access resource available for non-SDT; performing the random access based MT-SDT based on a first random access configuration for SDT in response to determining that the third time interval is less than or equal to the fourth time interval; performing the random access based MT-SDT based on a second random access configuration for non-SDT in response to determining that the third time interval is greater than the fourth threshold interval; The method of claim 1 further comprising:

12. The determining step comprises: determining whether configuration grant resources dedicated to MT-SDT are available; determining that the configuration grant-based MT-SDT has been performed for the terminal device in response to determining that the dedicated configuration grant resources are available; determining that the random access based MT-SDT has been performed for the terminal device in response to determining that there are no dedicated configuration grant resources available; The method of claim 1 , comprising:

13. receiving a third configuration from the network device indicating the dedicated configuration grant resource; The method of claim 12 further comprising:

14. determining a transmission configuration from a set of transmission configurations for the configuration grant-based MT-SDT in response to determining that the configuration grant-based MT-SDT has been performed for the terminal device; performing the configuration grant based MT-SDT based on the determined transmission configuration; The method of claim 1 further comprising:

15. The method of claim 14 , wherein the transmission configuration includes at least one of a modulation order, a target code rate, or a transport block size.

16. receiving the set of transmission configurations in a radio resource control release message from the network device; The method of claim 14 further comprising:

17. determining whether random access resources dedicated to MT-SDT are available in response to determining that the random access based MT-SDT has been performed for the terminal device; responsive to determining that the dedicated random access resource is available, performing the random access based MT-SDT based on the dedicated random access resource; The method of claim 1 further comprising:

18. receiving a fourth configuration from the network device indicating the dedicated random access resource; 20. The method of claim 17, further comprising:

19. performing an initial uplink transmission of the MT-SDT to the network device via a random access resource in response to determining that the random access based MT-SDT has been performed for the terminal device; or performing the initial uplink transmission to the network device via configured grant resources in response to determining that the configured grant-based MT-SDT has been performed for the terminal device. The method of claim 1 further comprising:

20. receiving a radio resource control release message together with downlink data from the network device; receiving a radio resource control resume message from the network device; receiving a radio resource control reject message from the network device; receiving a radio resource control setup message from the network device; or receiving downlink data from the network device while conducting subsequent transmission with the network device; 20. The method of claim 19, further comprising:

21. performing the initial uplink transmission, allocating uplink resources for a signaling radio bearer for the initial uplink transmission, including transmitting a radio resource control resume request message, by a media access control layer of the terminal device; 20. The method of claim 19, comprising:

22. The method of claim 21, wherein the radio resource control resume request message includes a second indication indicating the MT-SDT.

23. allocating resources for a radio bearer other than the signaling radio bearer for subsequent transmission of the MT-SDT by the media access control layer; 22. The method of claim 21 further comprising:

24. determining whether the initial uplink transmission was successfully performed; in response to determining that the initial uplink transmission was successfully performed, resuming a set of radio bearers configured with the SDT; performing a Packet Data Convergence Protocol (PDCP) and radio link control (RLC) re-establishment for the set of radio bearers; and 20. The method of claim 19, further comprising:

25. 1. A method of communication comprising: sending, in a network device in a radio access network, to a terminal device, a paging message including a first indication indicating that a mobile-terminated small data transmission (MT-SDT) is to be performed for the terminal device; receiving an initial uplink transmission of the MT-SDT from the terminal device via a random access resource or a configured grant resource; The method includes:

26. Receiving the initial uplink transmission comprises: receiving, from the terminal device, a radio resource control resume request message including a second indication indicating the MT-SDT; 26. The method of claim 25, comprising:

27. sending a radio resource control release message to the terminal device together with downlink data; transmitting a radio resource control resume message to the terminal device; sending a radio resource control rejection message to the terminal device; sending a radio resource control setup message to the terminal device; or Transmitting downlink data to the terminal device while performing subsequent transmissions with the terminal device.

26. The method of claim 25, further comprising:

28. sending to the terminal device a first configuration indicating a first threshold interval for configuration grant based MT-SDT decision; or sending to the terminal device a second configuration indicating a second threshold interval for random access based MT-SDT determination; 26. The method of claim 25, further comprising at least one of:

29. receiving information from the terminal device regarding the configuration grant-based MT-SDT that is not being performed for the terminal device; 30. The method of claim 28, further comprising:

30. The information is the first time interval is greater than the first threshold interval; or The first time interval 30. The method of claim 29, comprising at least one of:

31. sending a set of transmission configurations for configuration grant-based MT-SDT to the terminal device in a radio resource control release message; 26. The method of claim 25, further comprising:

32. 32. The method of claim 31, wherein the transmission configuration includes at least one of a modulation order, a target code rate, or a transport block size.

33. sending to the terminal device a third configuration indicating a configuration grant resource dedicated to the MT-SDT; or sending, to the terminal device, a fourth configuration indicating random access resources dedicated to the MT-SDT; 26. The method of claim 25, further comprising at least one of:

34. sending, to another network device, a request to obtain a context of the terminal device, the request including a third indication indicating that the MT-SDT has been performed for the terminal device; 26. The method of claim 25, further comprising:

35. A processor configured to carry out the method according to any one of claims 1 to 24. Terminal device.

36. A processor configured to carry out the method according to any one of claims 25 to 34. Network device.

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