Terminal device, communication device, and method of terminal device

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] Embodiments of the present disclosure generally relate to the field of telecommunications, and more particularly, to a communication method, apparatus, and computer storage medium for small data communication (SDT).

Background Art

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

[0003] In this case, in 3GPP Release 17, small data communication (SDT) in the inactive state is approved. SDT is a procedure that enables data communication while remaining in the inactive state (i.e., without transitioning to the connected state). Therefore, signaling overhead can be reduced. In 3GPP Release 17, only mobile originated SDT (MO-SDT) is defined. MO-SDT means that the trigger for SDT in the inactive state is caused by the arrival of uplink (UL) data. In 3GPP Release 18, one possible aspect of extension is mobile terminated SDT (MT-SDT). MT-SDT means that the trigger for SDT in the inactive state is caused by the arrival of downlink (DL) data. So far, the MT-SDT related technology is still not fully developed and further development is awaited.

Summary of the Invention

Problems to be Solved by the Invention

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

Means for Solving the Problems

[0005] In a first aspect, a communication method is provided. The method includes, at a terminal device, receiving 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 determining whether random access-based MT-SDT or configured grant-based MT-SDT has been performed for the terminal device.

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

[0007] In a third aspect, a terminal device is provided. The terminal device includes a processor and a memory connected to the processor. The memory stores instructions that, when executed by the processor, cause the terminal device to execute the method described in the first aspect of the present disclosure.

[0008] In a fourth aspect, a network device is provided. The network device includes a processor and a memory connected to the processor. The memory stores instructions that, when executed by the processor, cause the network device to execute the method described in the second aspect of the present disclosure.

[0009] In a fifth aspect, a computer-readable medium storing instructions is provided. When the instructions are executed on at least one processor, the at least one processor is caused to execute the method according to the first aspect of the present disclosure.

[0010] In a sixth aspect, a computer-readable medium storing instructions is provided. When the instructions are executed on at least one processor, the at least one processor is caused to execute the method according to the second aspect of the present disclosure.

[0011] Other features of the present disclosure will be readily understood from the following description.

Brief Description of the Drawings

[0012] The above and other objects, features, and advantages of the present disclosure will be made more apparent by describing some embodiments of the present disclosure in further detail with reference to the accompanying drawings.

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[0032] In the figure, the same or similar reference numerals represent the same or similar elements.

DETAILED DESCRIPTION OF THE INVENTION

[0033] Here, some embodiments are referred to explain the principles of the present disclosure. It should be understood that these embodiments are described for illustrative purposes only and are intended to assist those skilled in the art in understanding and implementing the present disclosure, without suggesting any limitation on the scope of the present disclosure. The disclosure described herein can be implemented in various ways different from the methods described below.

[0034] In the following description and claims, unless otherwise defined, all technical and scientific terms used herein shall have the same meaning as commonly understood by those skilled in the art of the present disclosure.

[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 computer, desktop computer, mobile phone, cellular phone, smartphone, personal digital assistant (PDA), portable computer, tablet, wearable device, Internet of Things (IoT) device, any Internet of Everything (IoE) device, machine type communication (MTC) device, in-vehicle device for vehicle-to-everything (V2X) communication, etc. Here, "X" in V2X represents a pedestrian, a vehicle or infrastructure / network, or an image acquisition device such as a digital camera, a game device, a music storage and playback device, or an Internet appliance enabling wireless or wired Internet access and browsing. The term "terminal device" may be used interchangeably with UE, mobile station, subscriber station, mobile terminal, user terminal, or wireless device. Also, the term "network device" refers to a device that can provide or host a cell or coverage with which a terminal device can communicate. Examples of network devices include, but are not limited to, Node B (NodeB or NB), evolved Node B (eNodeB or eNB), next-generation Node B (gNB), transmission and reception point (TRP), remote radio unit (RRU), radio head (RH), remote radio head (RRH), femto node, pico node, and other low-power nodes.

[0036] In one embodiment, the terminal device can be connected 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 regarding 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 regarding the settings of the terminal device set by the second network device may be transmitted from the second network device via the first network device. Information regarding the re - settings of the terminal device set by the second network device may be transmitted from the second network device directly or via the first network device to the terminal device.

[0037] As used herein, the singular forms "a", "an", and "the" include the plural forms as well, unless the context clearly dictates otherwise. The terms "comprising" and its variations should be understood as non - limiting terms meaning "including, but not limited to". The term "based on" should be understood as "at least partially based on". The terms "one embodiment" and "an 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", etc. may refer to different or the same objects. There may be other explicit and implicit definitions hereinafter.

[0038] In some examples, a value, procedure, or device is referred to as "best," "lowest," "highest," "minimum," "maximum," etc. Such descriptions are intended to indicate that a selection can be made from among many available functional alternatives, and it should be understood that such a selection need not be better, smaller, higher, or otherwise preferable to other selections.

[0039] Conventionally, there are various applications that perform small and infrequent data exchanges. For example, in some applications of mobile devices, SDT may include traffic from an instant messaging (IM) service, such as IM or heartbeat or keep-alive traffic from an email client and other services, push notifications in various applications, traffic from wearable devices (e.g., including periodic location information), etc. In some applications of 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), measurement and alarm information transmitted 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: uplink) responses. Furthermore, the MT-SDT procedure for initial downlink (DL) data reception in RRC_INACTIVE and subsequent UL / DL data communication is also supported. However, MT-SDT related technologies are still not fully developed and further development is awaited.

[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, with reference to the accompanying drawings, the principles and embodiments of the present disclosure will be described in detail.

[0042] Example of communication environment FIG. 1A is a schematic diagram showing an exemplary communication network 100 in which embodiments 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, the 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 within 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 the serving cell of the terminal device 110.

[0043] In the background of the present application, assume 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 the core network (CN: not shown). The network device 120 is an adjacent network device of the network device 130, and the cell 121 of the network device 120 is included within the RAN-based notification area (RNA) of the terminal device 110. The RNA of the terminal device 110 is set by the last serving network device, i.e., the network device 130. The RNA may cover a single cell or a plurality of cells, may be included within the CN registration area, and Xn connections can be utilized within the RNA. The terminal device 110 may move within the RNA without notifying the network.

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

[0045] As shown in FIG. 1A, the terminal device 110 may communicate with the network devices 120 and 130 via a channel such as a wireless communication channel. Communication in the communication network 100 may comply with 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), etc. Further, the communication may be performed according to any generation of communication protocol known currently or developed in the future. Examples of communication protocols include, but are not limited to, the first generation (1G), second generation (2G), 2.5G, 2.75G, third generation (3G), fourth generation (4G), 4.5G, fifth generation (5G) communication protocols.

[0046] Communication in the direction from the terminal device 110 to the network device 120 or 130 is referred to as UL communication, and communication in the direction from the network device 120 or 130 to the terminal device 110 is referred to as DL communication. The terminal device 110 can move between the network device 120 or 130 and, in some cases, the cells of other network devices. In UL communication, the terminal device 110 may transmit UL data and control information to the network device 120 or 130 via the UL channel. In DL communication, the network device 120 or 130 can transmit DL data and control information to the terminal device 110 via the DL channel.

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

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

[0049] Figure 1C is a schematic diagram 100C showing 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 Figure 1C, in CP, each of the terminal device 110, the network device 120, and the network device 130 includes an entity of layer L1, that is, an entity of the PHY layer (also referred to as a PHY entity), and an entity of the MAC layer (also referred to as a MAC entity), an entity of the RLC layer (also referred to as an RLC entity), an entity of the PDCP layer (also referred to as a PDCP entity), and one or more entities of the upper layer (L2 layer and L3 layer) including an entity of the radio resource control (RRC) layer (also referred to as an RRC entity). The RRC layer can be further referred to as an access stratum (AS) layer, and for this reason, the RRC entity can be further referred to as an AS entity. As shown in Figure 1C, the terminal device 110 may further include an entity of the non-access stratum (NAS) layer (also referred to as a NAS entity). The NAS layer on the network side is arranged not within the network device but within a core network (CN, not shown). In some cases, these entities form a stack structure.

[0050] Generally, a communication channel is divided into a logical channel, a transport channel, and a physical channel. The physical channel is the channel through which the PHY layer actually transmits information. For example, the 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 transport channel is the channel between the PHY layer and the MAC layer. For example, the transport channels 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] The logical channel is the channel between the MAC layer and the RLC layer. For example, the logical channels 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, the 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 transporting data plane data and at least one signaling radio bearer (SRB) for transporting control plane data. In the context of the present disclosure, the DRB may be configured to support transmissions in the inactive state (i.e., support SDT). Of course, the DRB may be configured not to support transmissions in the inactive state. The SRB may be configured to support transmissions in the inactive state. Of course, the SRB may be configured not to support transmissions in the inactive state.

[0054] In the RRC layer, three types of SRBs, namely SRB0, SRB1, and SRB2, are defined. SRB0 uses the CCCH for the establishment or re - establishment of an RRC connection. SRB1 uses the DCCH and is established when the RRC connection is established. SRB2 uses the 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 or receive data from the CN. The PDU session may correspond to an SDAP entity and may include a plurality of quality of service (QoS) flows. In the context of the present disclosure, the QoS flow may be configured to support transmissions in the inactive state. Of course, the QoS flow may be configured not to support transmissions in the inactive state.

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

[0057] Figure 2A is a schematic diagram showing a RAN paging procedure 200A that can implement some embodiments of the present disclosure. For the sake of explanation, 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 has occurred (201). For example, when the network device 130 receives DL data from the UPF or receives DL signaling (excluding the UE context release command message) associated with the terminal device 110 from the AMF, the network device 130 may determine that a RAN paging trigger event has occurred. Of course, the RAN paging trigger event is not limited to this example and may be in any other appropriate form.

[0059] When it is determined that an RAN paging trigger event has occurred, the network device 130 may perform paging within the cell corresponding to the RNA. For convenience, it is determined that the network device 120 is within the cell corresponding to the RNA, and the following description will be given 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 within 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 the paging message to the terminal device 110 (203). 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 appropriate information. If the paging message successfully arrives at the terminal device 110, the terminal device 110 may attempt to resume from the inactive state (204). So far, the RAN paging procedure has been completed. It should be understood that the RAN paging procedure 200A may include more or fewer steps and is not limited to the above example.

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

[0062] FIG. 2B is a schematic diagram showing a one-shot SDT procedure 200B that can implement some embodiments of the present disclosure. For the sake of explanation, the process 200B will be described with reference to FIG. 1. The process 200B may involve the terminal device 110 as shown in FIG. 1 and the network device 120 that serves the terminal device 110. This is only an example, and it should be understood that the process 200B may also be executed 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 send a RRC resume request together with UL data associated with data traffic to the network device 120 (211). For example, the terminal device 110 may send a RRC resume request together with UL data within MsgA of the two-step RACH procedure or Msg3 of the four-step RACH procedure. Of course, the terminal device 110 may further send a RRC resume request together with UL data in the configured grant (CG) resource. Upon receiving the RRC resume request and UL data, the network device 120 may send a 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 send a RRC release message together with DL data within Msg B of the two-step RACH procedure or Msg4 of the four-step RACH procedure. Also, the network device 120 may send a RRC release message together with DL data as a response to the transmission in the CG resource. At this point, the SDT procedure 200B ends.

[0064] Figure 2C is a schematic diagram showing an SDT procedure 200C including an initial transmission and subsequent transmissions that can implement some embodiments of the present disclosure. As shown in Figure 2C, a terminal device 110 in an inactive state may transmit an RRC resume request to a network device 120 together with UL data and a BSR (221). For example, the terminal device 110 may transmit an RRC resume request together with UL data and a BSR within MsgA of a two-step RACH procedure or Msg3 of a four-step RACH procedure. Of course, the terminal device 110 may further transmit an RRC resume request together with UL data in a configured grant (CG) resource. The RRC resume request may include a resume cause. Upon receiving the RRC resume request together with UL data and a BSR, the network device 120 may transmit an instruction for 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 to implicitly indicate a subsequent transmission. In some embodiments, the network device 120 may transmit DL data to the terminal device 110 together with an instruction. At this point, the initial transmission is completed.

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

[0066] Implementation example of the determination of the MT-SDT procedure Embodiments of the present disclosure provide a solution for determining and executing an MT-SDT procedure. This will be described in detail below in connection with FIGS. 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 the sake of explanation, 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 providing) 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., last serving cell providing) serving network device. Further, assume that the network device 130 starts RAN paging within the cell corresponding to the RNA, and the network device 120 receives the RAN paging from the network device 130. Assume that the terminal device 110 is within the cell 121.

[0068] As shown in FIG. 3, the network device 120 transmits (310) a paging message including an instruction (for convenience, also referred to as a first instruction in this specification) indicating that the MT-SDT is to be executed for the terminal device 110 to the terminal device 110. The network device 130 may also transmit the paging message to the terminal device 110 (310'). For example, the RAN paging may include information regarding the MT-SDT for the terminal device 110. Upon receiving the RAN paging, the network device 120 may transmit the first instruction to the terminal device 110 within the paging message. It should be understood that the transmission of the first instruction may be triggered by any other appropriate trigger event, and the present disclosure does not limit this aspect.

[0069] Since the terminal device 110 is within cell 121, the terminal device 110 may respond only to paging messages from the network device 120. When receiving a paging message from the network device 120, the terminal device 110 determines (320) whether RA-based MT-SDT or CG-based MT-SDT has been performed for the terminal device 110. In the case of RA-based MT-SDT, the initial UL transmission of MT-SDT is transmitted within Msg 3 or Msg A. In the case of CG-based MT-SDT, the initial UL transmission of MT-SDT is transmitted within the CG resource.

[0070] In some embodiments, upon receiving a paging message indicating MT-SDT, the RRC layer of the terminal device 110 determines that the MT-SDT procedure has been triggered, and the RRC layer of the terminal device 110 indicates to the MAC layer of the 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 the 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 determination 320 based on at least one of the information on the CG resource set for SDT, the information on the RA resource set for SDT, the information on the CG resource dedicated to MT-SDT, or the information on the RA resource 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 the information on the CG resource set for SDT, the information on the RA resource set for SDT, the information on the CG resource dedicated to MT-SDT, or the information on the RA resource 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 the CG resources are available for the SDT, i.e., whether there are valid CG resources. If there are CG resources available for the SDT, the terminal device 110 may determine that the CG-based MT-SDT has been executed. If there are no CG resources available for the SDT, the terminal device 110 may determine that the RA-based MT-SDT has been executed.

[0073] For purposes of illustration, in connection with Embodiments 1-7, some exemplary embodiments for Decision 320 are described in detail below.

[0074] Embodiment 1 Since the current CG-SDT setting is designed for MO-SDT, considering the service requirements, the period of the CG-SDT setting will become long. If the CG-SDT setting is used to transmit the initial UL transmission of the MT-SDT, it may introduce a large delay. Further, if the terminal device does not respond to the RAN paging message for a long time, the network device will page the terminal device within a wider area and, consequently, start the 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 FIGS. 4A and 4B.

[0075] FIG. 4A is a flowchart showing an exemplary process 400A for determining an MT-SDT procedure according to Embodiment 1 of the present disclosure. For example, the method 400A may be executed in the terminal device 110 as shown in FIG. 1. Hereinafter, for purposes of explanation, the method 400A will be described with reference to FIG. 1. The method 400A may include additional blocks not shown and / or may omit some of the blocks shown, and it should be understood that the scope of the present disclosure is not limited in this regard.

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

[0077] Returning to FIG. 4A, in block 420, the terminal device 110 may determine whether the first time interval is less than or equal to the first threshold interval. In some embodiments, the terminal device 110 may receive a setting (for convenience, also referred to as the first setting in this specification) indicating the first threshold interval from the network device 120. For example, the terminal device 110 may receive the first setting within the system information from the network device 120. As another example, the terminal device 110 may receive the first setting within an RRC message (e.g., an RRC release message or any other appropriate message) from the network device 120. Of course, any other appropriate method 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 the CG-based MT-SDT has been executed.

[0079] If the first time interval is greater than the first threshold interval, process 400A proceeds to block 440. At block 440, the terminal device 110 may determine that the RA-based MT-SDT has been executed. In some embodiments where the RA-based MT-SDT is executed, the terminal device 110 may store information regarding the CG-based MT-SDT that has not been executed 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 first time interval, i.e., the length of the actual delay.

[0080] According to the solution of Embodiment 1, it is possible to guarantee the delay of the CG-based MT-SDT.

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

[0082] FIG. 5A is a flowchart showing an exemplary process 500A for determining an MT-SDT procedure according to Embodiment 2 of the present disclosure. For example, method 500A may be executed in the terminal device 110 as shown in FIG. 1. Hereinafter, for the sake of explanation, method 500A will be described with reference to FIG. 1. Method 500A may include additional blocks not shown and / or may omit some of the blocks shown, and it should be understood that the scope of the present disclosure is not limited in this regard.

[0083] As shown in FIG. 5A, at 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 reception time 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 the time interval (for convenience, also referred to as the second time interval in this specification) between the time of the trigger of MT-SDT (i.e., the reception time of the paging message) and the time of the next RA resource available for SDT. For example, the next RA resource may be the next available PRACH opportunity or the next PUSCH resource available for two-step RACH.

[0085] FIG. 5B is a schematic diagram 500B showing an exemplary determination of the first time interval and the second time interval for 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 the CG opportunity 501. And the 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 the PRACH opportunity or PUSCH opportunity 503. And the time interval 504 from the trigger of MT-SDT to the PRACH opportunity or PUSCH opportunity 503 may also be determined.

[0086] Returning to FIG. 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 CG-based MT-SDT has been executed.

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

[0088] With the solution of Embodiment 2, it is also 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 the signaling overhead.

[0089] Embodiment 3 Currently, it is unclear whether the RA configuration for SDT or the RA configuration for non-SDT or both are available for MT-SDT. In the case of RA-based MT-SDT, the following possibilities exist. First, only the RA configuration for non-SDT is available for RA-based MT-SDT. Second, only the RA configuration for SDT is available for RA-based MT-SDT. Third, both the RA configuration for non-SDT and the RA configuration for SDT are available for RA-based MT-SDT.

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

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

[0092] FIG. 6A is a flowchart showing an exemplary process 600A for determining an MT-SDT procedure according to Embodiment 3 of the present disclosure. For example, method 600A may be executed in the terminal device 110 as shown in FIG. 1. Hereinafter, for the sake of explanation, method 600A will be described with reference to FIG. 1. Method 600A may include additional blocks not shown and / or some of the blocks shown may be omitted, and it should be understood that the scope of the present disclosure is not limited in this regard. Assume that it is determined that RA-based MT-SDT is to be executed for the terminal device 110.

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

[0094] At block 611, the terminal device 110 may determine whether the third time interval is less than or equal to a second threshold interval. In some embodiments, the terminal device 110 may receive a setting (for convenience, also referred to herein as the second setting) indicating the second threshold interval from the network device 120. For example, the terminal device 110 may receive the second setting within the system information from the network device 120. As another example, the terminal device 110 may receive the second setting within an RRC message (e.g., an RRC release message or any other suitable message) from the network device 120. Of course, any other suitable method 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. At block 612, the terminal device 110 may execute RA-based MT-SDT based on the RA setting for SDT (for convenience, also referred to herein as the first RA setting).

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

[0097] With the solution of Embodiment 3, it is 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 FIG. 6B.

[0099] FIG. 6B is a flowchart showing an exemplary process 600B for determining an MT-SDT procedure according to Embodiment 4 of the present disclosure. For example, method 600B may be executed in the terminal device 110 as shown in FIG. 1. Hereinafter, for the sake of explanation, method 600B will be described with reference to FIG. 1. Method 600B may include additional blocks not shown and / or may omit some of the blocks shown, and it should be understood that the scope of the present disclosure is not limited in this regard. Assume that RA-based MT-SDT is determined to be executed for the terminal device 110.

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

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

[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 setting for SDT.

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

[0104] It is possible to guarantee the delay of RA-based MT-SDT even by the solution of Embodiment 4. Furthermore, since it is not necessary to set the second threshold interval, it is possible to reduce the signaling overhead.

[0105] Embodiment 5 Currently, the size of the configured CG resource is designed for normal MO-SDT, so it has a large UL grant size. The UL grant size of the CG resource may be several thousand bits, but only 100 bits are sufficient for the initial UL transmission of MT-SDT. Therefore, it is necessary to insert many padding bits, which may cause waste of UL grants, 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. This embodiment will be described with reference to FIG. 7A.

[0107] FIG. 7A is a flowchart showing an exemplary process 700A for determining an MT-SDT procedure according to Embodiment 5 of the present disclosure. For example, method 700A may be executed in terminal device 110 as shown in FIG. 1. Hereinafter, for the sake of explanation, method 700A will be described with reference to FIG. 1. Method 700A may include additional blocks not shown and / or some of the blocks shown may be omitted, and it should be understood that the scope of the present disclosure is not limited in this regard.

[0108] As shown in FIG. 7A, at 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 shorter latency than the CG resources configured for MO-SDT. In some embodiments, terminal device 110 may receive a configuration (hereinafter also referred to as a third configuration for convenience) indicating CG resources dedicated to MT-SDT from network device 120.

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

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

[0111] According to the solution of Embodiment 5, waste of UL grants can be avoided, and the possibility of successful transmission can be improved.

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

[0113] FIG. 7B is a flowchart showing an exemplary process 700B for determining an MT-SDT procedure according to Embodiment 6 of the present disclosure. For example, method 700B may be executed in terminal device 110 as shown in FIG. 1. Hereinafter, for the sake of explanation, method 700B will be described with reference to FIG. 1. Method 700B may include additional blocks not shown and / or may omit some of the blocks shown, and it should be understood that the scope of the present disclosure is not limited in this regard. Assume that CG-based MT-SDT is determined to be executed for terminal device 110.

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

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

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

[0117] Also, according to the solution of Embodiment 6, it is possible to avoid waste of UL grants and improve the possibility of successful transmission.

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

[0119] FIG. 7C is a flowchart showing an exemplary process 700C for determining an MT-SDT procedure according to Embodiment 7 of the present disclosure. For example, the method 700C may be executed in the terminal device 110 as shown in FIG. 1. Hereinafter, for the sake of explanation, the method 700C will be described with reference to FIG. 1. The method 700C may include additional blocks (not shown) and / or may omit some of the blocks shown, and it should be understood that the scope of the present disclosure is not limited in this regard. Assume that it is determined that RA-based MT-SDT is to be performed for the terminal device 110.

[0120] As shown in FIG. 7C, in block 730, the 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, the terminal device 110 may receive from the network device 120 a configuration (also referred to herein as a fourth configuration for convenience) indicating the RA resources dedicated to MT-SDT.

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

[0122] The solution of Embodiment 7 can also avoid waste of UL grants and improve the possibility of successful transmission.

[0123] So far, some exemplary embodiments of the determination 320 of the MT-SDT procedure have been described. Returning to FIG. 3, based on the determination 320, the terminal device 110 executes 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 execute the initial UL transmission of MT-SDT via the RA resource. If the terminal device 110 determines that CG-based MT-SDT has been performed, the terminal device 110 may execute the initial UL transmission of MT-SDT via the CG resource.

[0124] In some embodiments, the terminal device 110 may execute 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 indicating MT-SDT (for convenience, also referred to as a second indication in this specification). In some alternative embodiments, the RRC resume request message may not include the second indication.

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

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

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

[0128] Thus, in the initial UL transmission of MT-SDT, the buffered data is not transmitted. For this reason, the bits of the data to be transmitted may be saved, and it becomes easier for the terminal device 110 to resume the RRC connection with the network device 120 normally.

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

[0130] Continuing to refer to FIG. 3, upon receiving the initial UL transmission, the network device 120 may send a request to the network device 130 to obtain the context of the terminal device 110 (335). This request includes an indication (hereinafter also referred to as the third indication for convenience) indicating that MT-SDT has been executed for the terminal device 110. For example, the network device 120 may send this request within a retrieve UE context request message. Of course, any other appropriate method is also possible.

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

[0132] Upon receiving the initial UL transmission, for example, an RRC resume request message indicating MT-SDT, the network device 120 may respond to the terminal device 110 in any appropriate manner. In some embodiments, the network device 120 may send an RRC release message to the terminal device 110 together with DL data (340). In some embodiments, the network device 120 may send an RRC resume message to the terminal device 110 (350). In some embodiments, the network device 120 may send an RRC rejection message to the terminal device 110 (360). In some embodiments, the network device 120 may send an RRC setup message to the terminal device 110 (370).

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

[0134] Example implementation of the method Therefore, the embodiments of the present disclosure provide communication methods implemented in a terminal device and a network device. Referring to FIGS. 8-9, these methods will be described below.

[0135] FIG. 8 is a diagram showing an exemplary communication method 800 implemented in a terminal device according to some embodiments of the present disclosure. For example, the method 800 may be executed in the terminal device 110 as shown in FIG. 1. Hereinafter, for the sake of explanation, the method 800 will be described with reference to FIG. 1. The method 800 may include additional blocks not shown and / or some of the blocks shown may be omitted, and it should be understood that the scope of the present disclosure is not limited in this regard.

[0136] In block 810, the terminal device 110 receives a paging message from the network device 120 within the RAN, the paging message including a first indication indicating that MT-SDT is to be 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 by the RRC layer of the terminal device 110 that the 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 the CG resource is available for the SDT. If the CG resource is available for the SDT, the terminal device 110 may determine that the CG-based MT-SDT has been executed for the terminal device 110. If there is no CG resource available for the SDT, the terminal device 110 may determine that the RA-based MT-SDT has been executed 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 the MT-SDT and the time of the next CG resource available for the SDT. If the first time interval is less than or equal to the first threshold interval, the terminal device 110 may determine that the CG-based MT-SDT has been executed for the terminal device 110. If the first time interval is greater than the first threshold interval, the terminal device 110 may determine that the RA-based MT-SDT has been executed for the terminal device 110. In some embodiments, the terminal device 110 may receive a first setting indicating the first threshold interval from the network device 120.

[0140] In some embodiments, when the RA-based MT-SDT is executed for the terminal device 110, the terminal device 110 may store information regarding the CG-based MT-SDT that has not been executed for the terminal device 110, and notify the stored information to the network device 120. 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.

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

[0142] 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. If the third time interval is less than or equal to the second threshold interval, the terminal device 110 may execute the RA-based MT-SDT based on the first RA setting for the SDT. The first RA setting 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 execute the RA-based MT-SDT based on the second RA setting for the non-SDT. In some embodiments, the terminal device 110 may receive a second setting indicating the second threshold interval from the network device 120.

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

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

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

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

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

[0148] In some embodiments, the terminal device 110 may receive an RRC release message together with DL data from the network device 120. In some embodiments, the terminal device 110 may receive an RRC resume message from the network device 120. In some embodiments, the terminal device 110 may receive an RRC rejection message from the network device 120. In some embodiments, the terminal device 110 may receive an RRC setup message from the network device 120. In some embodiments, the terminal device 110 may receive DL data from the network device 120 while performing subsequent transmissions with the network device 120.

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

[0150] In some embodiments, the terminal device 110 may determine whether the execution of the initial UL transmission has been successful. If the execution of the initial UL transmission is successful, the terminal device 110 may resume a set of radio bearers configured to have SDT and perform PDCP and RLC re-establishment for the set of radio bearers.

[0151] FIG. 9 is a diagram illustrating an exemplary 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 executed in the network device 120 as shown in FIG. 1. Hereinafter, for the sake of explanation, the method 900 will be described with reference to FIG. 1. The method 900 may include additional blocks not shown and / or some of the blocks shown may be omitted, and it should be understood that the scope of the present disclosure is not limited in this regard.

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

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

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

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

[0156] In some embodiments, the network device 120 may receive information regarding CG-based MT-SDT not performed on the terminal device 110 from 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 transmit a set of transmission settings for CG-based MT-SDT to the terminal device 110 within an RRC release message. In some embodiments, the transmission settings may include at least one of modulation order, target code rate, or TB size.

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

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

[0160] In this way, the MT-SDT procedure is executed. Since the realization of the methods described in FIGS. 8 and 9 substantially corresponds to the realization described in relation to FIGS. 3 to 7C, repeated descriptions of other details are omitted herein.

[0161] Examples of device and equipment realizations FIG. 10 is a schematic block diagram of a device 1000 suitable for realizing an embodiment of the present disclosure. The device 1000 can be considered as another exemplary embodiment of the terminal device 110 or the network device 120 shown in FIG. 1. Therefore, the device 1000 may be realized in the terminal device 110 or the network device 120, or as at least a part thereof.

[0162] As shown, apparatus 1000 includes a processor 1010, a memory 1020 connected to the processor 1010, an appropriate 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 part of a program 1030. The TX / RX 1040 is used for two-way communication. The TX / RX 1040 has at least one antenna to facilitate communication, although the access nodes mentioned in this specification may actually have multiple antennas. The communication interface may represent any interface necessary for communication with other network elements, such as an X2 / Xn interface for two-way communication between eNB / gNB, an S1 / NG interface for communication between a Mobility Management Entity (MME) / Access and Mobility Management Function (AMF) / SGW / UPF and eNB / gNB, a 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] It is assumed that when the program 1030 is executed by the associated processor 1010 as described herein with reference to FIGS. 1-9, it includes program instructions that enable the apparatus 1000 to operate in accordance with the embodiments of the present disclosure. The embodiments herein may be implemented by computer software executable by the processor 1010 of the apparatus 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. Further, 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] Memory 1020 may be of any type suitable for a local technology network and, by way of non-limiting example, may be implemented using any suitable data storage technology such as a non-transitory computer-readable storage medium, a semiconductor-based memory device, a magnetic memory device and system, an optical memory device and system, a fixed memory, and a removable memory. Only one memory 1020 is shown within device 1000, but there may be several physically different memory modules within device 1000. Processor 1010 may be of any type suitable for a local technology network and, by way of non-limiting example, may include one or more of a general-purpose computer, a dedicated computer, a microprocessor, a digital signal processor (DSP), and a processor based on a multi-core processor architecture. Device 1000 may have a plurality of processors, for example, an application-specific integrated circuit chip that is temporally dependent on a clock that synchronizes the main processor.

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

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

[0167] In some embodiments, the circuit determines whether the configured grant resource is available for SDT, and in response to a determination that the configured grant resource is available for SDT, determines that the configured grant-based MT-SDT has been executed for the terminal device, and in response to a determination that there is no configured grant resource available for SDT, is configured to determine that the random access-based MT-SDT has been executed for the terminal device.

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

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

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

[0171] In some embodiments, the circuit further determines, in response to determining that the random access-based MT-SDT has been executed for the terminal device, a third time interval between the trigger time of the MT-SDT and the time of the next random access resource available for the SDT, and in response to determining that the third time interval is less than or equal to a second threshold interval, executes the random access-based MT-SDT based on a first random access setting for the SDT, and in response to determining that the third time interval is greater than the second threshold interval, may be set to execute the random access-based MT-SDT based on a second random access setting for non-SDT. In some embodiments, the circuit may further be set to receive, from the network device, a second setting indicating the second threshold interval.

[0172] In some embodiments, the circuit further determines a third time interval between the time of the trigger of the MT-SDT and the time of the next random access resource available for SDT in response to a determination that the random access-based MT-SDT has been executed for the terminal device, determines 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, and executes the random access-based MT-SDT based on a first random access setting for SDT in response to a determination that the third time interval is less than or equal to the fourth time interval, and executes the random access-based MT-SDT based on a second random access setting for non-SDT in response to a determination that the third time interval is greater than the fourth threshold interval.

[0173] In some embodiments, the circuit determines whether a dedicated configuration grant resource for MT-SDT is available, determines that the configuration grant-based MT-SDT has been executed for the terminal device in response to a determination that the dedicated configuration grant resource is available, and is configured to determine that the random access-based MT-SDT has been executed for the terminal device in response to a determination that there is no available dedicated configuration grant resource. In some embodiments, the circuit may further be configured to receive a third configuration indicating the dedicated configuration grant resource from the network device.

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

[0175] In some embodiments, the circuit is further configured to determine, in response to a determination that the random access-based MT-SDT has been executed for the terminal device, whether dedicated random access resources for the MT-SDT are available, and in response to a determination that the dedicated random access resources are available, be configured to execute the random access-based MT-SDT based on the dedicated random access resources. In some embodiments, the circuit may further be configured to receive, from the network device, a fourth setting indicating the dedicated random access resources.

[0176] In some embodiments, the circuit is further configured to execute, in response to a determination that the random access-based MT-SDT has been executed for the terminal device, an initial uplink transmission of the MT-SDT to the network device via random access resources, or execute, in response to a determination that the configured grant-based MT-SDT has been executed for the terminal device, the initial uplink transmission to the network device via configured grant resources.

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

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

[0179] In some embodiments, the circuit may be further configured to determine whether the execution of the initial uplink transmission is successful, and in response to a determination that the execution of the initial uplink transmission is successful, resume a set of radio bearers configured to have the SDT, and perform PDCP and RLC re-establishment for the set of radio bearers.

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

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

[0182] In some embodiments, the circuit may further be configured to transmit a radio resource control release message to the terminal device together with downlink data, transmit a radio resource control resume message to the terminal device, transmit a radio resource control rejection message to the terminal device, transmit 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 circuit may further be configured to perform at least one of transmitting a first setting indicating a first threshold interval for determining the setup grant-based MT-SDT to the terminal device or transmitting a second setting indicating a second threshold interval for determining the random access-based MT-SDT to the terminal device.

[0184] In some embodiments, the circuit may further be configured to receive information regarding the setup grant-based MT-SDT that has not been performed for the terminal device from 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 circuit may further be configured to transmit a set of transmission settings for the setup grant-based MT-SDT to the terminal device in a radio resource control release message. In some embodiments, the transmission settings include at least one of modulation order, target code rate, or transport block size.

[0186] In some embodiments, the circuit may further be configured to cause the terminal device to execute at least one of: transmitting a third configuration indicating a configuration grant resource dedicated to the MT-SDT to the terminal device; or transmitting a fourth configuration indicating a random access resource dedicated to the MT-SDT to the terminal device.

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

[0188] As used herein, the term "circuit" may mean a hardware circuit and / or a combination of a hardware circuit and software. For example, the circuit may be a combination of analog and / or digital hardware circuits and software / firmware. As yet another example, the 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, the 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 "circuit" also includes the implementation of a hardware circuit or only one or more processors, or a portion of a hardware circuit or one or more processors and their (or their) accompanying software and / or firmware.

[0189] Overall, the various embodiments of the present disclosure may be implemented in hardware or dedicated circuitry, software, logic, or any combination thereof. Some aspects may be implemented in hardware, and other aspects may be implemented in firmware or software executable by a controller, microprocessor, or other computing device. The various aspects of the embodiments of the present disclosure are illustrated and described using block diagrams, flowcharts, or some other pictorial representation, but the blocks, devices, systems, techniques, or methods described herein are, by way of non-limiting example, hardware, software, firmware, dedicated circuitry or logic, general-purpose hardware or controllers or other computing devices, 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 program modules, that are executed within a device on a target physical processor or virtual processor to perform the processes or methods described above with reference to FIGS. 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 functions of the program modules may be connected or divided among the program modules as needed. The machine-executable instructions of the program modules may be executed within a local or distributed device. In a distributed device, the program modules may be located in both local and remote storage media.

[0191] The program code for executing the method of the present disclosure may be described in any combination of one or more programming languages. These program codes are provided to a processor or a controller of a general-purpose computer, a dedicated computer, or other programmable data processing devices, and when executed by the processor or the controller, the program codes implement the functions / operations specified in the flowchart and / or block diagram. The program code may be executed entirely on the machine, partially on the machine, as an independent 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, and the machine-readable medium may be any tangible medium that can be used by or associated with an instruction execution system, apparatus, or device and that can contain or store a program related thereto. 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, apparatus, or device, or any suitable combination of the foregoing media. More specific examples of the machine-readable storage medium may include electrical connections 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 disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0193] Although the operations have been described in a particular order, it should be understood that in order to obtain the desired results, these operations need not be performed in the particular order shown or in a sequential order, nor is it required that all of the operations described be performed. 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 present disclosure, but rather as descriptions of features that may be specific to a particular embodiment. Some features described in the context of individual embodiments may be combined and implemented 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 sub-combination.

[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 exemplary forms of implementing the claims.

Claims

1. A terminal device, comprising: communication means for communicating with a communication device; receiving means for receiving a first message including first information indicating that it is MT-SDT (Mobile-terminated small data transmission) from the communication device; wherein when a first time interval indicating a time interval between the start of the MT-SDT procedure and a configured grant (CG) opportunity for SDT is equal to or less than a first threshold, the communication means executes a configured grant SDT (CG-SDT) procedure; a terminal device.

2. The receiving means: receives a second message including information indicating the first threshold from the communication device; The terminal device according to claim 1.

3. The communication means indicates from the RRC (radio resource control) layer to the MAC (medium access control) layer of the terminal device that the MT-SDT has been triggered, and the MAC layer determines that random access-based MT-SDT or CG-based MT-SDT is to be executed; The terminal device according to claim 1 or 2.

4. The communication means determines whether a CG resource for SDT is available, and when it is determined that the CG resource is available, determines that the CG-based MT-SDT is to be executed, and when it is determined that the CG resource is not available, determines that random access-based MT-SDT is to be executed for the terminal device; The terminal device according to claim 3.

5. A communication device, comprising: communication means for communicating with a terminal device; transmitting means for transmitting a first message including first information indicating that it is MT-SDT (Mobile-terminated small data transmission) to the terminal device; wherein when a first time interval indicating a time interval between the start of the MT-SDT procedure and a configured grant (CG) opportunity for SDT is equal to or less than a first threshold, the communication means executes a configured grant SDT (CG-SDT); a communication device.

6. The transmitting means: transmits a second message including information indicating the first threshold to the terminal device; The communication device according to claim 5.

7. A method for a terminal device, comprising: communicating with a communication device; Receiving a first message including first information indicating that it is MT-SDT (Mobile-terminated small data transmission) from the communication device, When a first time interval indicating a time interval between the start of the MT-SDT procedure and an opportunity for a configured grant (CG) to the SDT is equal to or less than a first threshold, including performing CG-SDT, A method for a terminal device.

8. Receiving a second message including information indicating the first threshold from the communication device, including this, The method for a terminal device according to claim 7.

9. From the RRC (radio resource control) layer to the MAC (medium access control) layer of the terminal device, indicating that the MT-SDT has been triggered, The MAC layer determines that random access-based MT-SDT or CG-based MT-SDT is to be performed. The method for a terminal device according to claim 7 or 8.

10. Determining whether a CG resource for SDT is available, When it is determined that the CG resource is available, determining that the CG-based MT-SDT is to be performed, When it is determined that the CG resource is not available, determining that random access-based MT-SDT is to be performed on the terminal device, The method for a terminal device according to claim 9.

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