Start of small data transmission

Abstract

To allow small data transmission (SDT) to be initiated.SOLUTION: A first device determines whether the initiation of SDT is permitted at a first protocol layer of the first device. According to the determination that SDT is permitted to be initiated at the first protocol layer, the first device determines whether SDT is permitted to be initiated at a second protocol layer of the first device. According to the determination that SDT is permitted to be initiated at the second protocol layer, the first device initiates an SDT communication procedure with the second device via the first protocol layer. This solution is capable of not only avoiding incorrect resumption of a radio bearer when the SDT procedure cannot be performed, but also avoiding unnecessary interactions between protocol layers.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] Embodiments of the present disclosure generally relate to the field of telecommunications, and more specifically, to devices, methods, apparatuses, and computer-readable storage media for initiating small data transmission (SDT).

Background Art

[0002] In some communication systems, a communication device can transition between an inactive state and a connected state. In the inactive state, the communication device may not have established a connection with a communication network device. To avoid unnecessary signaling overhead and power consumption for establishing or re-establishing a connection, a communication device in the inactive state can perform small data transmission (SDT) procedures with other communication devices without the need to establish a connection with the other communication devices.

Summary of the Invention

[0003] Generally, exemplary embodiments of the present disclosure provide a solution for initiating SDT. If there are embodiments not included in the claims, they should be construed as useful examples for understanding the various embodiments of the present disclosure.

[0004] In a first embodiment, a first device is provided. The first device comprises at least one processor and at least one memory containing computer program code, wherein the at least one memory and the computer program code are configured to cause the first device to perform the following using at least one processor: determine whether small data transmission is permitted to be initiated at a first protocol layer of the first device; determine whether small data transmission is permitted to be initiated at a second protocol layer of the first device in accordance with the determination that small data transmission is permitted to be initiated at the first protocol layer; and initiate a small data transmission communication procedure with a second device via the first protocol layer in accordance with the determination that small data transmission is permitted to be initiated at the second protocol layer.

[0005] A second embodiment provides a method, the method comprising: determining at a first device whether small data transmission is permitted to be initiated at a first protocol layer of the first device; determining, in accordance with the determination that small data transmission is permitted to be initiated at a first protocol layer, whether small data transmission is permitted to be initiated at a second protocol layer of the first device; and initiating a small data transmission communication procedure with a second device via the first protocol layer, in accordance with the determination that small data transmission is permitted to be initiated at a second protocol layer.

[0006] In a third embodiment, a first apparatus is provided. The first apparatus includes means for determining whether small data transmission is permitted to be initiated at a first protocol layer of the first apparatus; means for determining, in accordance with the determination that small data transmission is permitted to be initiated at a first protocol layer, whether small data transmission is permitted to be initiated at a second protocol layer of the first apparatus; and means for initiating a communication procedure for small data transmission with a second apparatus via the first protocol layer, in accordance with the determination that small data transmission is permitted to be initiated at a second protocol layer.

[0007] In a fourth aspect, a computer-readable medium is provided. The computer-readable medium comprises program instructions that cause a device to perform at least the method according to the first aspect.

[0008] It should be understood that the Summary of the Invention section is not intended to identify any important or essential features of the embodiments of this disclosure, nor is it intended to be used to limit the scope of this disclosure. Other features of this disclosure will be readily apparent through the following description.

[0009] Here, several exemplary embodiments will be described with reference to the attached drawings. [Brief explanation of the drawing]

[0010] [Figure 1] This document illustrates an exemplary communication environment in which exemplary embodiments of the present disclosure may be implemented. [Figure 2] This disclosure illustrates an exemplary protocol stack for a device on which exemplary embodiments of this disclosure may be implemented. [Figure 3] The present disclosure illustrates several exemplary embodiments of the signaling flow for SDT initiation across the protocol layers of a device. [Figure 4] A flowchart of a method implemented in a first device according to some exemplary embodiments of the present disclosure is shown. [Figure 5] A simplified block diagram of a device suitable for carrying out exemplary embodiments of this disclosure is shown. [Figure 6] The following are block diagrams of exemplary computer-readable media according to some exemplary embodiments of the present disclosure. [Modes for carrying out the invention]

[0011] Throughout the drawing, the same or similar reference numbers represent the same or similar elements.

[0012] The principles of this disclosure are described here with reference to several exemplary embodiments. These embodiments are described for illustrative purposes only and are intended to assist those skilled in the art in understanding and implementing this disclosure, but should not be considered to imply any limitation on the scope of this disclosure. The embodiments described herein can be implemented in various ways other than those described below.

[0013] In the following description and claims, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art to which this disclosure belongs, unless otherwise defined.

[0014] References in this disclosure such as “one embodiment,” “embodiment,” and “exemplary embodiment” indicate that the embodiments described may include certain features, structures, or characteristics, but not all embodiments necessarily include certain features, structures, or characteristics. Furthermore, such phrases do not necessarily refer to the same embodiment. Moreover, where certain features, structures, or characteristics are described in relation to an embodiment, it is considered that using such features, structures, or characteristics in relation to other embodiments, whether expressly stated or not, would be within the scope of knowledge of those skilled in the art.

[0015] In this specification, terms such as “first” and “second” may be used to describe various elements, but it will be understood that these elements should not be limited by these terms. These terms are used solely to distinguish one element from another. For example, without departing from the scope of the exemplary embodiments, the first element may be referred to as the second element, and similarly, the second element may be referred to as the first element. As used herein, the terms “and / or” encompass all combinations of one or more of the listed terms.

[0016] The terms used herein are intended solely to describe specific embodiments and are not intended to limit the exemplary embodiments. The singular forms “a,” “an,” and “the” used herein are intended to include the plural form unless otherwise clearly indicated by the context. It will be further understood that the terms “comprises,” “comprising,” “has,” “having,” “includes,” and / or “including,” when used herein, identify the presence of the described features, elements, and / or components, but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof.

[0017] The term "circuit" as used in this application means (a) Hardware-only circuit embodiments (such as analog and / or digital circuit-only embodiments), (b) A combination of hardware circuitry and software, for example (where applicable), (i) combinations of analog and / or digital hardware circuits(s) and software / firmware, and (ii) Any part of a hardware processor(s) and software (including digital signal processors(s), software, and memory(s) that work together to cause a device such as a mobile phone or server to perform various functions), (c) Hardware circuits(s) and / or processors(s), such as microprocessors(s) or parts of microprocessors(s), which require software (e.g., firmware) for operation but do not need software if it is not necessary for operation. This could refer to one or more or all of them.

[0018] This definition of circuit applies to all uses of this term in this application, including all claims. As further examples, the term circuit as used in this application also includes embodiments of mere hardware circuits or processors (or multiple processors), or embodiments of a part of a hardware circuit or processor and the software and / or firmware associated therewith. The term circuit also includes, for example, baseband integrated circuits or processor integrated circuits in mobile devices, or similar integrated circuits in servers, cellular network devices, or other computing or network devices, where they constitute a component of a particular claim.

[0019] As used herein, the term “communication network” refers to a network conforming to any preferred communication standard, such as New Radio (NR), Long-Term Evolution (LTE), LTE-A, Broadband Code Division Multiple Access (WCDMA), High-Speed ​​Packet Access (HSPA), and Narrowband Internet of Things (NB-IoT). Furthermore, communication between terminal devices and network devices in a communication network may be carried out in accordance with any preferred generation of communication protocol, including but not limited to first-generation (1G), second-generation (2G), 2.5G, 2.75G, third-generation (3G), fourth-generation (4G), 4.5G, and fifth-generation (5G) communication protocols, and / or any other protocols currently known or to be developed in the future. Embodiments of this disclosure may be applied to a variety of communication systems. Given the rapid development in communications, there will naturally be future communication technologies and systems that can embody this disclosure. The scope of this disclosure should not be considered to be limited to the aforementioned systems only.

[0020] As used herein, the term "network device" refers to a node within a communication network, and a terminal device accesses the network via the node and receives services therefrom. The network device may refer to a base station (BS) or an access point (AP) depending on the applicable terms and technologies, for example, Node B (NodeB or NB), evolved Node B (eNodeB or eNB), NR NB (also referred to as gNB), remote radio unit (RRU), radio header (RH), remote radio head (RRH), relay, access backhaul integrated (IAB) node, low-power nodes such as femto, pico, etc., as well as non-terrestrial network (NTN) devices or non-ground network devices such as satellite network devices, low-earth orbit (LEO) satellites and geostationary earth orbit (GEO) satellites, aircraft network devices, etc. In some exemplary embodiments, a radio access network (RAN) split architecture includes a central unit (CU) and a distributed unit (DU) in an IAB donor node. The IAB node includes a mobile terminal (IAB-MT) part that operates like a UE with respect to a parent node, and the DU part of the IAB node operates like a base station with respect to the next-hop IAB node.

[0021] The term "terminal device" refers to any end device that may be capable of wireless communication. Examples, though not limited to, terminal devices may also be called communication devices, user equipment (UE), subscriber stations (SS), mobile subscriber stations, mobile stations (MS), or access terminals (AT). Terminal devices may include, but are not limited to, mobile phones, cellular phones, smartphones, voice over IP (VoIP) phones, wireless local loop phones, tablets, wearable terminal devices, personal digital assistants (PDAs), portable computers, desktop computers, image capture terminal devices such as digital cameras, game terminal devices, music storage and playback appliances, in-vehicle wireless terminal devices, wireless endpoints, mobile stations, laptop embedded devices (LEEs), laptop mounted devices (LMEs), USB dongles, smart devices, wireless customer equipment (CPEs), Internet of Things (IoT) devices, watches or other wearable devices, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in industrial processing chains and / or automated processing chains), consumer electronics, and devices operating on commercial and / or industrial wireless networks. Terminal devices may also correspond to the mobile termination (MT) portion of IAB nodes (e.g., relay nodes). In the following explanation, the terms “terminal device,” “communication device,” “terminal,” “user equipment,” and “UE” may be used interchangeably.

[0022] As used herein, the terms "resource", "transmission resource", "resource block", "physical resource block" (PRB), "uplink resource", or "downlink resource" may refer to any resource for performing communication, such as communication between a terminal device and a network device, and may include resources in the time domain, resources in the frequency domain, resources in the spatial domain, resources in the code domain, or other resources enabling communication. In the following, for the purpose of explaining some exemplary embodiments of the present disclosure, resources in both the frequency domain and the time domain are used as examples of transmission resources. It should be noted that the exemplary embodiments of the present disclosure are equally applicable to other resources in other domains.

[0023] FIG. 1 shows an exemplary communication environment 100 in which an exemplary embodiment of the present disclosure may be implemented. In communication environment 100, a plurality of communication devices including a first device 110 and a second device 120 may communicate with each other.

[0024] In the example of FIG. 1, the first device 110 is shown as a terminal device, and the second device 120 is shown as a network device that provides services to the terminal device. The serving area of the second device 120 may be referred to as cell 102.

[0025] It should be understood that the devices shown in FIG. 1 and their connections are for illustrative purposes only and do not imply any limitations. Environment 100 may include any suitable number of devices adapted to implement embodiments of the present disclosure. Although not shown, one or more additional devices may be disposed within cell 102, and it will be understood that one or more additional cells may be deployed within environment 100. Note that the second device 120 is shown as a network device, but it may be a device other than a network device. The first device 110 is shown as a terminal device, but it may be a device other than a terminal device.

[0026] In some exemplary embodiments, when the first device 110 is a terminal device and the second device 120 is a network device, the link from the second device 120 to the first device 110 is referred to as a downlink (DL), while the link from the first device 110 to the second device 120 is referred to as an uplink (UL). In a DL, the second device 120 is a transmit (TX) device (i.e., a transmitter) and the first device 110 is a receive (RX) device (i.e., a receiver). In a UL, the first device 110 is a TX device (i.e., a transmitter) and the second device 120 is an RX device (i.e., a receiver).

[0027] Communication in communication environment 100 may be carried out according to any suitable communication protocol(s), which may include, but are not limited to, cellular communication protocols such as first-generation (1G), second-generation (2G), third-generation (3G), fourth-generation (4G), and fifth-generation (5G), wireless local network communication protocols such as IEEE 802.11, and / or any other protocols currently known or to be developed in the future. Furthermore, communication may utilize any suitable wireless communication technology, which may include, but are not limited to, code division multiplexing access (CDMA), frequency division multiplexing access (FDMA), time division multiplexing access (TDMA), frequency division duplexing (FDD), time division duplexing (TDD), multiple input multiple output (MIMO), orthogonal frequency division multiplexing (OFDM), discrete Fourier transform spread OFDM (DFT-s-OFDM), and / or any other technologies currently known or to be developed in the future.

[0028] The first device 110 and the second device 120 may include a protocol stack having multiple protocol layers. Figure 2 shows an exemplary protocol stack of the first device 110. As shown, the protocol stack of the first device 110 may include a Radio Resource Control (RRC) layer 202, a Packet Data Convergence Protocol (PDCP) layer 204, and a Medium Access Control (MAC) layer 206. Each of the protocol layers may perform corresponding services and functions to facilitate communication between the first device 110 and other devices. Although not shown, the protocol stack of the first device 110 may include further protocol layers in addition to the RRC, PDCP, and MAC layers. Other protocol layers may include a Non-Access Stratum (NAS) above the RRC layer, a Radio Link Control (RLC) layer between the RRC and MAC layers, and a Physical (PHY) layer.

[0029] Although not shown, the second device 120 may include a protocol stack similar to that of the first device 110. Inter-device communication, such as between the first device 110 and the second device 120, typically takes place within the same protocol layer between the two devices. For example, communication from the RRC layer 202 of the first device 110 is transmitted through the PDCP layer 204 and MAC layer 206, and then sent to the second device 120 via the PHY layer. Once received by the second device 120, the communication is transmitted through the protocol layers of the second device 120 in the reverse order.

[0030] During operation, a device (e.g., a terminal device) can transition between an inactive state and a connected state. The inactive state may sometimes be referred to as inactive mode or RRC_INACTIVE state / mode, and these terms are used interchangeably herein. The connected state may sometimes be referred to as connected mode, active state / mode, or RRC_CONNECTED state / mode, and these terms are used interchangeably herein.

[0031] Normally, transitioning a terminal device from an inactive state to a connected state by establishing or re-establishing a connection between the terminal device and a network device involves a certain amount of signaling overhead and power consumption. For at least one data transmission from an inactive terminal device, connection setup and subsequent disconnection can occur, even if the data packets are small and infrequent, resulting in unnecessary power consumption and signaling overhead. Currently, inactive terminal devices may be capable of performing Small Data Transmission (SDT). As used herein, the term "SDT" refers to a type of transmission in which small amounts of data are transmitted, although other terms may also be used.

[0032] There are various applications that involve the exchange of relatively small amounts of data. For example, in some applications on mobile devices, SDT may include traffic from instant messaging (IM) services, heartbeat or keep-alive traffic from IM or email clients and other services, push notifications from various applications, and / or traffic from wearable devices (e.g., including periodic positioning information). In some applications on non-mobile devices, SDT may include sensor data (e.g., temperature and pressure readings transmitted periodically or event-triggered on an IoT network), measurement and warning information sent from smart meters, and / or similar.

[0033] The signaling overhead and latency incurred by inactive devices due to small data packets are an overall issue affecting not only network performance and efficiency but also battery performance. Any device with intermittent small data packets in an inactive state typically benefits from enabling SDT. Ideally, devices should apply several criteria for choosing between SDT and non-SDT. These criteria may relate to data availability, resource availability, channel quality, and SDT mode-specific checks. However, currently, there is no solution that specifically defines how SDT and non-SDT selection is made at different protocol layers of a device.

[0034] According to some exemplary embodiments of this disclosure, a solution is provided for initiating an SDT procedure. In this solution, permission to initiate an SDT is checked at different protocol layers. If it is determined that initiating an SDT is permitted, the SDT communication procedure is initiated. This solution further checks for permission to initiate an SDT at other layers before the protocol layer decides to initiate an SDT.

[0035] By splitting the SDT initiation criteria across different protocol layers, each protocol layer can focus on its own relevant services and functions related to SDT. Furthermore, various combinations of SDT initiation criteria are possible between protocol layers. Moreover, considering that SDT can resume several authorized radio bearers when the SDT procedure can be initiated, defining an optimal criterion check division across protocol layers is beneficial. Therefore, it is possible to avoid not only incorrect resumption of radio bearers when the SDT procedure cannot be executed, but also unnecessary interaction between protocol layers.

[0036] Exemplary embodiments of this disclosure are described in detail below with reference to the attached drawings.

[0037] Herein, we refer to Figure 3, which shows a signaling flow 300 for SDT initiation according to some exemplary embodiments of the present disclosure. The signaling flow 300 may include operations and interactions between different protocol layers of the first device 110. For discussion purposes, we refer to the communication environment shown in Figure 1 and the protocol stack shown in Figure 2.

[0038] During operation, if there is data to send to, for example, a second device 120, the first device 110 performs the corresponding processing at each protocol layer of the protocol stack. For example, if data arrives at the PDCP layer 204 of the first device 110 (301), other protocol layers, including the RRC layer 202 and the MAC layer 206, may operate to initiate a communication procedure with the second device 120. The first device 110 may also decide within its own protocol stack whether to initiate an SDT or non-SDT communication procedure. In some exemplary embodiments, the first device 110 may be in an inactive state or in other operating states in which SDT can be selected for communication.

[0039] Specifically, the first device 110 determines at a first protocol layer, for example, a higher layer, the RRC layer 202, whether SDT initiation is permitted (or available) (302). SDT initiation is triggered at the first device 110 when several predetermined criteria are met. According to embodiments of the present disclosure, the criteria are divided among the protocol layers of the first device 110, and one or more criteria are checked at the RRC layer 202. Exemplary criteria at the RRC layer 202 are discussed in detail below.

[0040] If it is determined at RRC layer 202 that SDT initiation is permitted (or available), for example, if it is determined that the criteria set at RRC layer 202 are met, the first device 110 determines at a second protocol layer, such as a lower layer MAC layer 206, whether SDT initiation is permitted, instead of directly resuming the radio bearer configured for SDT (304). According to embodiments of the present disclosure, one or more criteria are checked at MAC layer 206 to determine whether SDT initiation is permitted.

[0041] In some exemplary embodiments, if the RRC layer 202 determines that the initiation of SDT is permitted, the RRC layer 202 may send a request to the MAC layer 206 to determine whether the SDT is permitted (303). In response to the request from the RRC layer 202, the MAC layer 206 may operate to determine whether one or more criteria for permitting the initiation of SDT are met.

[0042] If MAC layer 206 determines that SDT initiation is permitted or available, for example, if it determines that the criteria set in MAC layer 206 are met, RRC layer 202 may initiate the SDT communication procedure (also referred to as the SDT procedure) with the second device 120 (306A). In some exemplary embodiments, if MAC layer 206 determines that SDT initiation is permitted, MAC layer 206 may send an indication of permission or availability to initiate SDT to RRC layer 202 (305A). In response to this indication, RRC layer 202 may act to initiate the SDT communication procedure with the second device 120.

[0043] In some exemplary embodiments, the MAC layer 206 also verifies that SDT is permitted, so the RRC layer 202 may decide to perform an SDT RRC resume on the radio bearer for SDT to initiate the SDT communication procedure (306A). Radio bearers to resume for SDT may include a signaling radio bearer (SRB) for SDT, e.g., SRB1 or SRB2, and a data radio bearer (DRB). In exemplary embodiments, the RRC layer 202 may resume SRB1 or SRB2 for SDT. In exemplary embodiments, the RRC layer 202 may send a request to the PDCP layer 204 to resume at least one radio bearer for SDT (e.g., an SRB or a DRB) (307). In some exemplary embodiments, the PDCP layer 204 may, after the radio bearer resume, inject data for transmission to a lower layer, such as the RLC layer (309), which is further processed by the MAC layer 206. In some exemplary embodiments, to initiate the SDT communication procedure, the RRC layer 202 may further send a Common Control Channel (CCCH) RRC Resume Request for SDT to the MAC layer 206 (308A). Through the above process, the SDT communication procedure may be initiated at the first device 110, and data may be transmitted to the second device 120 using the SDT communication procedure.

[0044] In conventional protocol stacks, if the RRC layer of a device determines that it can initiate SDT communication with another device, the RRC layer may directly resume a radio bearer such as a DRB and / or SRB. If the MAC layer determines that SDT is unavailable, for example, if resources for SDT are invalid, the incorrectly resumed radio bearer can cause complex problems in the protocol stack. According to exemplary embodiments of this disclosure, by checking for permission to initiate SDT at both the RRC and MAC layers, it is possible to avoid incorrect resumption of the radio bearer if the MAC layer determines that SDT is unavailable, which would have resulted in unnecessary interaction between protocol layers.

[0045] Several detailed examples of the criteria for permitting SDT initiation, which are divided between RRC layer 202 and MAC layer 206, are discussed below. To better understand the criteria discussed, several exemplary SDT modes are first introduced.

[0046] In some exemplary embodiments, SDT may be performed based on a Random Access (RA) procedure or using a configured grant (CG). Therefore, two or more different SDT modes may be defined based on the resource type used in the SDT procedure (e.g., RA resources or CG resources). In some examples, an SDT mode based on an RA procedure may be referred to as an RA-based SDT mode or RA-SDT mode. An SDT mode that uses CG for data communication may be referred to as a CG-based SDT mode or CG-SDT mode. In an RA-based SDT mode, data may be transmitted from a first device 110 to a second device 120 in MsgA of a two-step RA procedure or in Msg3 of a four-step RA procedure. In a CG-based SDT mode, data transmission(s) may be performed directly using CG resources, such as configured grant type 1 resources.

[0047] In some exemplary embodiments, the RA procedure may include a two-step RA procedure or a four-step RA procedure, so different RA-based SDT modes may exist, namely SDT modes using a two-step RA procedure and SDT modes using a four-step RA procedure. An RA-based SDT mode based on a two-step RA resource may be referred to as a two-step RA-based SDT mode, and an RA-based SDT mode based on a four-step RA resource may be referred to as a four-step RA-based SDT mode. According to the two-step RA-based SDT mode, data may be transmitted from the first device 110 to the second device 120 in MsgA of the two-step RA procedure initiated with the second device 120. According to the four-step RA-based SDT mode, data may be transmitted in Msg3 of the four-step RA procedure initiated with the second device 120.

[0048] While several SDT modes are described in some exemplary embodiments of this disclosure, it will be understood that other applicable SDT modes may exist. In some exemplary embodiments, multiple different SDT modes may be defined based on the specific number or range of consecutive data transmissions permitted in the SDT procedure. For example, one SDT mode may be defined as allowing only one data transmission during the SDT procedure, while another SDT mode may be defined as allowing two or more data transmissions during the SDT procedure.

[0049] To determine whether SDT is permitted at RRC layer 202 (302), wireless bearer data availability-based criteria may be applied to SDT at RRC layer 202. In some exemplary embodiments, RRC layer 202 may determine whether there is one or more wireless bearers permitted for SDT, and whether data is available on at least one wireless bearer permitted for SDT. In some cases, not all wireless bearers are configured for SDT. If RRC layer 202 determines that there is no data available on the wireless bearer(s) for SDT, RRC layer 202 may determine that SDT is not permitted. If it determines that such data exists, RRC layer 202 may determine that the wireless bearer data availability-based criteria are met.

[0050] In some exemplary embodiments, alternatively or additionally, the RRC layer 202 may further determine whether one or more threshold-based criteria for SDT are met. Threshold-based criteria may include criteria based on a data volume threshold set for SDT. The RRC layer 202 may determine whether the amount of data being transmitted meets the requirements based on the data volume threshold set for SDT. In some exemplary embodiments, the requirements may not be specific to the SDT mode but common to SDT, and the SDT data volume threshold may be set in the RRC layer 202. If the amount of data being transmitted is less than (or strictly below) the data volume threshold, the requirements for SDT may be defined as being met. In this case, the RRC layer 202 may determine whether to allow the initiation of SDT by comparing the amount of data with the data volume threshold.

[0051] In some exemplary embodiments, the first device 110 may be configured with one or more SDT modes, and one or more data volume thresholds specific to one or more SDT modes may be set in the RRC layer 202. The requirements for initiating an SDT mode may be met if the data volume threshold specific to this SDT mode is met. For example, a first data volume threshold may be set for a first SDT mode, and a second data volume threshold may be set for a second SDT mode. The first data volume threshold may be lower than the second data volume threshold. If the first device 110 can determine that the amount of data being transmitted is less than or equal to the first data volume threshold of the first SDT mode, the first SDT mode may be selected to initiate. In some exemplary embodiments, if the first device 110 can determine that the amount of data being transmitted exceeds the first data volume threshold but is less than or equal to the second data volume threshold of the second SDT mode, the first device 110 may select the second SDT mode.

[0052] In some exemplary embodiments, in addition to, or as an alternative to, data volume threshold-based criteria, threshold-based criteria may include criteria based on a channel quality threshold set for SDT. The channel quality between the first device 110 and the second device 120 may be compared to the channel quality threshold to determine whether SDT is permitted. In some exemplary embodiments, channel quality may be measured based on one or more of the following: Criteria signal received power (RSRP), Criteria signal received quality (RSRQ), and / or other factors reflecting the channel quality between the first device 110 and the second device 120, such as signal-to-interference noise ratio (SINR) or path loss. The RRC layer 202 may determine whether the channel quality meets the requirements based on the channel quality threshold set for SDT. In some exemplary embodiments, the requirements may not be specific to the SDT mode but common to SDT, and the channel quality threshold for SDT may be set in the RRC layer 202. If the channel quality exceeds the channel quality threshold, the requirements for SDT may be defined as being met. In this case, the RRC layer 202 may determine whether SDT initiation is permitted by comparing the channel quality with a channel quality threshold. In some exemplary embodiments, one or more channel quality thresholds specific to one or more SDT modes may be set in the RRC layer 202, similar to data volume threshold-based criteria. By comparing the channel quality with the SDT mode-specific thresholds, the RRC layer 202 may determine which SDT mode(s) may be permitted to initiation.

[0053] In some exemplary embodiments, alternatively or additionally, RRC layer 202 may further apply several resource availability-based criteria for SDT. RRC layer 202 may determine whether resources configured for SDT exist. For example, RRC layer 202 may determine whether a CG configured for SDT exists and / or RA resources configured for SDT exist. If the first device 110 is configured with CG and / or RA resources for SDT, RRC layer 202 determines that initiating SDT is permitted.

[0054] In some exemplary embodiments, the RRC layer 202 does not need to determine the validity of the resources configured for the SDT. Verification of the resources configured for the SDT may be performed at the MAC layer 206. As shown above, the SDT communication procedure is initiated by the RRC layer 202 only after the MAC layer 206 has also confirmed that the SDT is permitted. Therefore, it is possible to prevent the RRC layer 202 from initiating the communication procedure when no valid resources are available.

[0055] In some exemplary embodiments, the RRC layer 202 may not be configured to determine what type of RA procedure should be initiated for communication with the second device 120, or whether an RA procedure or a CG-based procedure should be initiated. Therefore, the criteria applied in the RRC layer 202 may not be specific to the SDT mode, but are general to all possible SDT modes.

[0056] In some exemplary embodiments, the RRC layer 202 may be able to determine which one or more SDT modes may be permitted after applying the criteria of the RRC layer 202. For example, the RRC layer 202 may consist of one or more data volume-based criteria or channel quality-based criteria specific to one or more SDT modes, such as a CG-based SDT mode, an RA-based SDT mode, a two-step-based SDT mode, or a four-step-based SDT mode. In this case, if any of the criteria are met, the RRC layer 202 may determine that the initiation of the corresponding SDT mode(s) is permitted.

[0057] In some exemplary embodiments, the RRC layer 202 may perform checks based on criteria that do not depend on the selection of the SDT mode or the selection of the UL carrier (e.g., a normal UL carrier or an auxiliary UL (SUL) carrier).

[0058] The various criteria in RRC Layer 202 have been discussed above. It will be understood that RRC Layer 202 may apply one or more of the above criteria and / or other possible criteria to determine whether SDT is permitted. The scope of this disclosure is not limited in this regard.

[0059] As described above, if RRC layer 202 determines that initiating an SDT is permitted based on the criteria of RRC layer 202, RRC layer 202 cannot directly initiate the SDT communication procedure to communicate data. Instead, RRC layer 202 may send a request to MAC layer 206 to further determine whether and when an SDT may be permitted before initiating the communication procedure (303). In some exemplary embodiments, if RRC layer 202 determines that initiating one or more target SDT modes is permitted, RRC layer 202 may send a request to MAC layer 206 to determine whether initiating one or more target SDT modes is permitted at a second protocol layer (303).

[0060] When MAC layer 206 receives a request to determine whether to authorize one or more specific target SDT modes, it may apply MAC layer 206 criteria for those SDT modes and determine, based on MAC layer 206 criteria, whether any of them are authorized. Otherwise, MAC layer 206 receives a general request from RRC layer 202 and determines whether any SDT mode can be initiated. MAC layer 206 may apply MAC layer 206 criteria to check for authorization of SDT, or authorization of all possible SDT modes configured for the first device 110.

[0061] To determine whether SDT is permitted at the RRC layer 202 (304), a radio bearer data availability-based criteria may be applied to the SDT. In some exemplary embodiments, if there are no various modes designated for the SDT, the RRC layer 202 may determine whether initiating the SDT is permitted. In some exemplary embodiments, the MAC layer 206 may determine permission to initiate with respect to one or more SDT modes configured for the first device 110. As described above, in some exemplary embodiments, the SDT modes may be indicated by the RRC layer 202.

[0062] In some exemplary embodiments, the first device 110 may consist of multiple UL carriers (such as typical UL carriers or SUL carriers) to communicate with the second device 120. In such cases, the MAC layer 206 may select one of the UL carriers for communication. In some exemplary embodiments, the selection of a UL carrier may follow a legacy selection mechanism independent of SDT. In exemplary embodiments, the selection of a UL carrier may be performed based on a channel quality threshold that is not specifically set for SDT or any SDT mode.

[0063] In some exemplary embodiments, a channel quality threshold may be set for SDT and also set in MAC layer 206, which may differ from the threshold used in legacy selection mechanisms. MAC layer 206 may determine, in order to select a UL carrier, whether the channel quality across a given UL carrier meets requirements based on the channel quality threshold set for SDT. In some examples, the requirement may be met if the channel quality across a given UL carrier exceeds a certain channel quality threshold. In this case, MAC layer 206 may select the given UL carrier.

[0064] Once a UL carrier is selected, MAC layer 206 may apply further criteria (if any) to determine whether SDT can be initiated on the selected UL carrier. In some exemplary embodiments, MAC layer 206 may apply resource-effectiveness-based criteria for SDT. MAC layer 206 may determine whether resources are configured and enabled for SDT, or for a particular SDT mode.

[0065] For example, if a CG for performing SDT is configured for a first device 110, the MAC layer 206 may determine whether the CG is enabled by determining whether the timing advance (TA) of the first device 110 is enabled. If the TA is enabled, the CG is determined to be enabled. In some exemplary embodiments, a new TA timer for TA maintenance may be set for CG-based SDT. In some exemplary embodiments, additionally or alternatively, the effectiveness of the CG for SDT may be based on other factors, including whether one or more beams are enabled for the CG, whether the CG is associated with a selected synchronous signal block (SSB), and whether the channel quality (e.g., RSRP) has changed beyond a corresponding channel quality threshold. The scope of this disclosure is not limited in this regard.

[0066] In some exemplary embodiments, if an RA resource is configured for a first device 110, the MAC layer 206 may further determine whether the RA resource is valid for SDT. In some exemplary embodiments, the MAC layer 206 may determine that a two-step RA resource or a four-step RA resource is available and valid for SDT. The RA resource may include, for example, a physical random access channel (PRACH) and preamble, as well as a dedicated radio resource for the RA procedure of SDT, if any.

[0067] In some exemplary embodiments, by checking the availability of CG and / or RA resources, MAC layer 206 may be able to determine whether initiating a CG-based SDT mode or an RA-based SDT mode (e.g., a two-step RA-based SDT mode or a four-step RA-based SDT mode) is permitted.

[0068] In some exemplary embodiments, alternatively or additionally, the MAC layer 206 may further determine whether one or more threshold-based criteria for SDT are met. Threshold-based criteria may include criteria based on a data volume threshold set for SDT, and criteria based on a channel quality threshold set for SDT. In some exemplary embodiments, if the MAC layer 206 is composed of threshold-based criteria, it may not be necessary for the RRC layer 202 to perform threshold-based criterion checks for SDT. In some exemplary embodiments, both the RRC layer 202 and the MAC layer 206 may perform threshold-based criterion checks for SDT, but the two layers may have different thresholds set.

[0069] In some exemplary embodiments, similar to the criteria described above with respect to the RRC layer 202, the criteria based on data volume thresholds may include requirements based on data volume thresholds set for SDT, or requirements based on one or more data volume thresholds specifically set for one or more SDT modes. In some exemplary embodiments, the criteria based on channel quality thresholds may include requirements based on channel quality thresholds set for SDT, or requirements based on one or more channel quality thresholds specifically set for one or more SDT modes. By comparing the amount of data transmitted with the corresponding data volume threshold(s) and / or by comparing the channel quality with the corresponding channel quality threshold(s) and / or by comparing the channel quality with the corresponding channel quality threshold(s). In some exemplary embodiments, SDT is permitted if both the criteria based on data volume thresholds and channel quality thresholds are met.

[0070] Various criteria in MAC layer 206 have been discussed above. It will be understood that MAC layer 206 may apply one or more of the above criteria and / or other possible criteria to determine whether to authorize SDT. The scope of this disclosure is not limited in this regard. If MAC layer 206 determines that it is authorized to initiate SDT as described above, MAC layer 206 may transmit an indication of authorization or availability for initiating SDT to RRC layer 202 (305A). In some exemplary embodiments, if MAC layer 206 determines that a particular SDT mode is authorized, MAC layer 206 may transmit an indication of the authorized SDT mode to RRC layer 202 (305A). In response to the indication from MAC layer 206, RRC layer 202 may act to initiate an SDT communication procedure with the second device 120. If a particular SDT mode is indicated, RRC layer 202 may initiate a communication procedure according to the SDT mode.

[0071] In the embodiments described above, the operation of the protocol layer when it is determined that SDT is permitted has been explained. In some cases, if it is found that SDT has been rejected at RRC layer 202 or MAC layer 206, for example, if one or more of the criteria at RRC layer 202 or MAC layer 206 are not met, the first device 110 may initiate a non-SDT communication procedure with the second device 120. Refer to Figure 2 again. For example, if RRC layer 202 determines that SDT is rejected because there are no resources or radio bearers configured for or permitted for SDT, RRC layer 202 may initiate a non-SDT communication procedure (also referred to as a non-SDT procedure) with the second device 120 (306B). For example, RRC layer 202 may decide to resume an SBR, e.g., SBR1, for the non-SDT communication procedure. RRC layer 202 may further send a CCCH RRC resume request for non-SDT to MAC layer 206 (308B). The PDCP layer 204 and MAC layer 206 may, as appropriate, operate to perform non-SDT communication procedures. Using non-SDT procedures, data may be transmitted to the second device 120.

[0072] If RRC layer 202 determines that SDT is permitted, but MAC layer 206 determines that the initiation of SDT is not permitted, MAC layer 206 may send an indication to RRC layer 202 that the initiation of SDT is rejected or unavailable (305B). Upon receiving such an indication from MAC layer 206, RRC layer 202 may initiate a non-SDT communication procedure accordingly (306B).

[0073] Interactions between protocol layers have been discussed above. Exemplary procedures performed at MAC layer 206 according to several exemplary embodiments can be summarized as follows. The corresponding steps of the signaling flow 300 are shown below. - When MAC receives a request to start the SDT procedure (step 303), it performs a SUL / UL selection based on the SUL / UL_SDT_RSRP threshold (which may be the same as or different from the conventional SUL / UL RSRP threshold) (step 304). - After selecting the UL carrier (step 304), - MAC performs CG verification (including TA, beam, RSRP criteria, etc.) on the selected UL carrier (step 304), - If there is a valid CG for SDT, - MAC indicates to RRC that it can start (CG-)SDT and performs CG-SDT (step 305A), - If no valid CG exists (is not configured, or none of the criteria are met), - MAC checks the availability of 2-step and 4-step RA-SDT and performs 2-step / 4-step RA selection based on the 2-step / 4-step RA SDT-RSRP threshold (which may be the same as or different from the conventional 2-step / 4-step selection RSRP threshold) (step 304). - If there are RA resources available for SDT for the selected RA type, - MAC indicates to RRC that it can initiate (RA-)SDT, and therefore performs RA-SDT (step 305A), - If neither a CG valid for SDT nor a 2-step or 4-step RA resource valid for SDT exists on the selected UL (note that the first device 110 may consist only of CG-SDT resources without RA-SDT, or only of 2-step or 4-step RA configured for SDT) (step 304), - MAC indicates to RRC that the SDT procedure cannot be performed (step 305B).

[0074] An exemplary procedure performed in the RRC layer 202 according to several exemplary embodiments can be summarized as follows. The corresponding steps of the signaling flow 300 are shown below. - SDT criteria include, for example, whether SDT is configured for the relevant DRB and whether the UL payload meets the SDT threshold, and whether the SDT-RSRP criteria are met (step 302), - Request MAC to perform SDT resource verification (step 303), - If an SDT availability indication is received from MAC (step 305A), - Resume SRB1 / (SRB2) / SDT DRB(multiple) (steps 307 and 308A), - Perform SDT resume and send SDT resume to MAC (steps 306A and 309), - If an unavailable indication is received from MAC (step 305B), - Resume SRB1, - Perform a non-SDT resume (steps 306B and 308B).

[0075] Figure 4 shows a flowchart of an exemplary method 400 performed with the first device 110 according to some exemplary embodiments of the present disclosure. For discussional purposes, method 400 will be described in reference to the first device 110 with respect to Figure 1.

[0076] In block 410, the first device 110 determines whether the initiation of SDT is permitted at the first protocol layer of the first device 110 (e.g., RRC layer 202). If the initiation of SDT is permitted at the first protocol layer, in block 420, the first device 110 determines whether the initiation of SDT is permitted at the second protocol layer of the first device 110 (e.g., MAC layer 206). If the initiation of SDT is permitted at the second protocol layer, in block 430, the first device 110 initiates the SDT communication procedure with the second device 120 via the first protocol layer.

[0077] In some exemplary embodiments, if the initiation of SDT is rejected at the first or second protocol layer, in block 440, the first device 110 may initiate a non-SDT further communication procedure with the second device 120 via the first protocol layer.

[0078] In some exemplary embodiments, the first device 110 may determine that initiating SDT is permitted at the first protocol layer by determining that at least one of the following criteria is met: resources for SDT are configured; resources for at least one SDT mode are configured; data is available on at least one radio bearer authorized for SDT; or the amount of data being transmitted meets requirements based on a first data volume threshold set for SDT.

[0079] In some exemplary embodiments, at least one SDT mode includes at least one of the following: a first SDT mode based on a setting grant, a second SDT mode based on a random access procedure, a third SDT mode based on a two-step random access procedure, and a fourth SDT mode based on a four-step random access procedure.

[0080] In some exemplary embodiments, if the initiation of SDT is permitted at the first protocol layer, the first device 110 may cause the first protocol layer to send one of the following requests to the second protocol layer: a first request to determine whether the initiation of SDT is permitted at the second protocol layer, or a second request to determine whether the initiation of a target SDT mode is permitted at the second protocol layer.

[0081] In some exemplary embodiments, the first device 110 may determine whether the initiation of SDT is permitted at the second protocol layer by determining whether the initiation of SDT is permitted at the second protocol layer in response to a first request, or by determining whether the initiation of a target SDT mode is permitted at the second protocol layer in response to a second request.

[0082] In some exemplary embodiments, the first device 110 may determine whether the initiation of SDT is permitted in the second protocol layer by determining whether the initiation of at least one SDT mode is permitted in the second protocol layer.

[0083] In some exemplary embodiments, if the second protocol layer permits the initiation of at least one of the SDT modes, the first device 110 may cause the second protocol layer to transmit an indication of the determined SDT mode to the first protocol. In response to the indication of the determined SDT mode, the first device 110 may initiate an SDT communication procedure via the first protocol layer by initiating a communication procedure according to the determined SDT mode.

[0084] In some exemplary embodiments, the first device 110 may determine that the second protocol layer is permitted to initiate SDT if at least one of the following criteria is met: resources configured for SDT are enabled; resources configured for at least one SDT mode are enabled; the amount of data transmitted meets the requirements based on a second data volume threshold set for SDT; the amount of data transmitted meets the requirements based on a third data volume threshold set for at least one SDT mode; the channel quality between the first device 110 and the second device 120 meets the requirements based on a first quality threshold set for SDT, or the channel quality meets the requirements based on a second quality threshold set for at least one SDT mode.

[0085] In some exemplary embodiments, the first device 110 may determine whether the initiation of SDT is permitted at the second protocol layer by selecting one of a plurality of uplink carriers and determining whether the initiation of SDT is permitted on the selected uplink carrier.

[0086] In some exemplary embodiments, the first device 110 may select one of a plurality of uplink carriers by determining, with respect to a given uplink carrier, whether the channel quality across a given uplink carrier meets the requirements based on a fourth quality threshold set for SDT or a fifth quality threshold set for SDT mode, and selecting the given uplink carrier according to the determination that the channel quality meets the requirements based on the fourth quality threshold or the fifth quality threshold.

[0087] In some exemplary embodiments, the first device 110 may initiate the SDT communication procedure via the first protocol layer by causing the first protocol layer to send a third request to resume at least one radio bearer for the SDT to the third protocol layer of the first device 110 (e.g., PDCP layer 204). In some exemplary embodiments, the third protocol layer includes a packet data convergence protocol layer.

[0088] In some exemplary embodiments, a first apparatus (e.g., first device 110) capable of performing any of the methods 300 may comprise means for performing each operation of the methods 300. The means can be implemented in any preferred form. For example, the means can be implemented in a circuit / or software module. The first apparatus may be implemented as the first device 110, or may be included in the first device 110.

[0089] In some exemplary embodiments, the first device includes means for determining whether the initiation of small data transmission is permitted at a first protocol layer of the first device; means for determining whether the initiation of small data transmission is permitted at a second protocol layer of the first device in accordance with the determination that the initiation of small data transmission is permitted at the first protocol layer; and means for initiating a small data transmission communication procedure with a second device (e.g., a second device 120) via the first protocol layer in accordance with the determination that the initiation of small data transmission is permitted at the second protocol layer.

[0090] In some exemplary embodiments, means for determining whether the initiation of small data transmission is permitted at the first protocol layer include means for determining whether the initiation of small data transmission is permitted at the first protocol layer by determining that at least one of the following criteria is met: resources for small data transmission are configured; resources for at least one small data transmission mode are configured; data is available on at least one radio bearer on which small data transmission is permitted; or the amount of data to be transmitted meets requirements based on a first data volume threshold set for small data transmission.

[0091] In some exemplary embodiments, at least one small data transmission mode includes at least one of the following: a first small data transmission mode based on a setting grant, a second small data transmission mode based on a random access procedure, a third small data transmission mode based on a two-step random access procedure, and a fourth small data transmission mode based on a four-step random access procedure.

[0092] In some exemplary embodiments, the first device further includes means for causing the first device to transmit from the first protocol layer to the second protocol layer one of the following requests: a first request for determining whether the second protocol layer is permitted to initiate small data transmission, or a second request for determining whether the second protocol layer is permitted to initiate a target small data transmission mode, in accordance with a determination that the first protocol layer permits the initiation of small data transmission.

[0093] In some exemplary embodiments, means for determining whether the initiation of small data transmission is permitted at the second protocol layer include means for determining whether the initiation of small data transmission is permitted at the second protocol layer in response to a first request, or means for determining whether the initiation of a target small data transmission mode is permitted at the second protocol layer in response to a second request.

[0094] In some exemplary embodiments, means for determining whether the initiation of small data transmission is permitted at the second protocol layer include means for determining whether the initiation of at least one small data transmission mode is permitted at the second protocol layer.

[0095] In some exemplary embodiments, the first device further includes means for causing an indication of a determined small data transmission mode to be transmitted from the second protocol layer to the first protocol layer, in accordance with a determination that the second protocol layer permits the initiation of at least one of the small data transmission modes. In some exemplary embodiments, means for initiating a small data transmission communication procedure include means for initiating a communication procedure via the first protocol layer in accordance with the determined small data transmission mode, in response to the indication of the determined small data transmission mode.

[0096] In some exemplary embodiments, means for determining whether the initiation of small data transmission is permitted at the second protocol layer include means for determining whether the initiation of small data transmission is permitted at the second protocol layer by determining that at least one of the following criteria is met: resources configured for small data transmission are available; resources configured for at least one small data transmission mode are available; the amount of data transmitted meets the requirements based on a second data volume threshold set for small data transmission; the amount of data transmitted meets the requirements based on a third data volume threshold set for at least one small data transmission mode; the channel quality between the first and second devices meets the requirements based on a first quality threshold set for small data transmission; or the channel quality meets the requirements based on a second quality threshold set for at least one small data transmission mode.

[0097] In some exemplary embodiments, means for determining whether the initiation of small data transmission is permitted at the second protocol layer include means for selecting one of a plurality of uplink carriers, and means for determining whether the initiation of small data transmission is permitted on the selected uplink carrier.

[0098] In some exemplary embodiments, means for selecting one of a plurality of uplink carriers include means for determining, with respect to a given uplink carrier among the plurality of uplink carriers, whether the channel quality across a given uplink carrier meets requirements based on a fourth quality threshold set for small data transmission or requirements based on a fifth quality threshold set for a small data transmission mode, and means for selecting a given uplink carrier according to the determination that the channel quality meets requirements based on the fourth quality threshold or requirements based on the fifth quality threshold.

[0099] In some exemplary embodiments, means for initiating a communication procedure for small data transmission via a first protocol layer include means for causing a third request to be transmitted from the first protocol layer to the third protocol layer of the first device for resuming at least one radio bearer for small data transmission.

[0100] In some exemplary embodiments, the third protocol layer includes a packet data convergence protocol layer. In some exemplary embodiments, the first protocol layer includes a radio resource control layer, and the second protocol includes a medium access control layer.

[0101] In some exemplary embodiments, the first device further includes means for initiating a further communication procedure for non-small data transmission with the second device via the first protocol layer, in accordance with a determination that the initiation of small data transmission is rejected at the first or second protocol layer.

[0102] In some exemplary embodiments, the first device further comprises means for performing method 400 or other operations in some exemplary embodiments of the first device 110. In some exemplary embodiments, the means comprises at least one processor and at least one memory containing computer program code, the at least one memory and the computer program code being configured to cause the execution of the first device using at least one processor.

[0103] Figure 5 is a simplified block diagram of a device 500 suitable for carrying out exemplary embodiments of the present disclosure. The device 500 may be provided to carry out a communication device such as the first device 110 or the second device 120 shown in Figure 1, for example. As shown, the device 500 includes one or more processors 510, one or more memories 520 connected to the processors 510, and one or more communication modules 540 connected to the processors 510.

[0104] The communication module 540 is for bidirectional communication. The communication module 540 has one or more communication interfaces that facilitate communication with one or more other modules or devices. The communication interfaces may represent any interfaces necessary for communication with other network elements. In some exemplary embodiments, the communication module 540 may include at least one antenna.

[0105] The processor 510 may be any type suitable for a local technical network and may include, in non-limiting examples, one or more of the following: a general-purpose computer, a dedicated computer, a microprocessor, a digital signal processor (DSP), and a processor based on a multi-core processor architecture. The device 500 may have multiple processors, such as an application-specific integrated circuit chip configured to time-track a clock that synchronizes the main processor.

[0106] Memory 520 may include one or more non-volatile memories and one or more volatile memories. Examples of non-volatile memories include, but are not limited to, read-only memory (ROM) 524, electrically programmable read-only memory (EPROM), flash memory, hard disks, compact discs (CDs), digital video discs (DVDs), optical discs, laser discs, and other magnetic and / or optical storage devices. Examples of volatile memories include, but are not limited to, random-access memory (RAM) 522 and other volatile memories that do not persist while the power is off.

[0107] The computer program 530 includes computer executable instructions that are executed by the associated processor 510. The program 530 may be stored in memory, for example, ROM 524. The processor 510 can perform any preferred operations and processes by loading the program 530 into RAM 522.

[0108] The exemplary embodiments of the disclosure can be implemented by program 530 so that device 500 can perform any of the processes of the disclosure discussed with reference to Figures 3 and 4. The exemplary embodiments of the disclosure may also be implemented by hardware or by a combination of software and hardware.

[0109] In some exemplary embodiments, the program 530 may be tangibly contained in a computer-readable medium (such as memory 520) that may be contained within device 500, or in other storage devices accessible by device 500. Device 500 may load the program 530 from the computer-readable medium into RAM 522 for execution. The computer-readable medium may include any type of tangible non-volatile storage device, such as ROM, EPROM, flash memory, hard disk, CD, and DVD. Figure 6 shows an example of a computer-readable medium 600, which may be in the form of a CD, DVD, or other optical storage disc. The program 530 is stored on the computer-readable medium.

[0110] Typically, various embodiments of the present disclosure may be implemented in hardware, dedicated circuitry, software, logic, or any combination thereof. Some embodiments may be implemented in hardware, while others may be implemented in firmware or software that can be executed by a controller, microprocessor, or other computing device. Various embodiments of the present disclosure are illustrated and described using block diagrams, flowcharts, or some other graphical representations, but it will be understood that any blocks, apparatus, systems, techniques, or methods described herein may be implemented, in non-limiting examples, in hardware, software, firmware, dedicated circuitry or logic, general-purpose hardware or controllers or other computing devices, or any combination thereof.

[0111] This disclosure also provides at least one computer program product tangibly stored in a non-temporary computer-readable storage medium. The computer program product includes computer-executable instructions, which, for example, are contained in a program module and, when executed on a device on a target physical or virtual processor, perform one of the methods described above with reference to Figures 3-4. Typically, a program module includes routines, programs, libraries, objects, classes, components, or data structures that perform a specific task or implement a specific abstract data type. The functionality of the program modules may be combined or separated amongst the program modules, as desired in various embodiments. The machine-executable instructions of the program modules may be executed in a local device or in a distributed device. In a distributed device, the program modules reside on both local and remote storage media.

[0112] Program code for performing the methods of this disclosure may be written in any combination of one or more programming languages. This program code may be provided to a processor or controller of a general-purpose computer, a dedicated computer, or other programmable data processing device, and as a result, when the program code is executed by the processor or controller, it will perform the functions / operations defined in the flowcharts and / or block diagrams. The program code may run entirely on the machine, partially on the machine, as a standalone software package, partially on the machine and partially on a remote machine, or entirely on a remote machine or remote server.

[0113] In the context of this disclosure, computer program code or related data may be carried by any suitable carrier so that a device, apparatus, or processor can perform the various processes and operations described above. Examples of carriers include signals and computer-readable media.

[0114] Computer-readable media may be computer-readable signal media or computer-readable storage media. Computer-readable media may include, but are not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any preferred combination thereof. More specific examples of computer-readable storage media include electrical connections with one or more wires, portable computer diskettes, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any preferred combination thereof.

[0115] Furthermore, although the operations are described in a specific order, this should not be understood as requiring that such operations be performed in a specific order or sequence shown, or that all exemplified operations be performed, in order to obtain the desired results. In certain circumstances, multitasking and parallel processing may be advantageous. Similarly, the above discussion includes details of several specific embodiments, but these should not be interpreted as limitations on the scope of this disclosure, but rather as descriptions of features that may be specific to a particular embodiment. Certain features described in the context of a separate embodiment may be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented separately in multiple embodiments, or in any preferred partial combination.

[0116] While this disclosure is described in language specific to structural features and / or methodological actions, it should be understood that the disclosure as defined in the attached claims is not necessarily limited to the specific features or actions described herein. Rather, the specific features and actions described herein are disclosed as exemplary forms of implementing the claims.

Claims

1. At least one processor, At least one memory location containing program code, A terminal device equipped with, The at least one memory and the program code are used by the at least one processor to operate while the terminal device is in an inactive state of radio resource control (RRC). Determining that small data transmission is permitted to be initiated at the RRC protocol layer of the terminal device, If the small data transmission is permitted to be initiated at the RRC protocol layer, it is determined that the small data transmission is permitted to be initiated at the Media Access Control (MAC) protocol layer of the terminal device. If the small data transmission is permitted to be initiated at the MAC protocol layer, the RRC protocol layer initiates the communication procedure for the small data transmission with the network device. It is configured to cause the terminal device to execute the following: The terminal device is configured to use the at least one memory and the program code to cause the terminal device to initiate the communication procedure for the small data transmission at the RRC protocol layer in response to an instruction from the MAC protocol layer that the small data transmission is permitted to be initiated at the MAC protocol layer.

2. The at least one memory and the program code are further processed using the at least one processor. If the small data transmission is permitted to be initiated at the RRC protocol layer, a request is sent from the RRC protocol layer to the MAC protocol layer to determine whether the small data transmission is permitted to be initiated at the MAC protocol layer. In response to the aforementioned request, it is determined that the small data transmission is permitted to be initiated at the MAC protocol layer, If the small data transmission is permitted to be initiated at the MAC protocol layer, the MAC protocol layer transmits the instruction to the RRC protocol layer, The terminal device according to claim 1, configured to cause the terminal device to perform the above.

3. The at least one memory and the program code are further processed using the at least one processor. If the small data transmission is permitted to be initiated at the RRC protocol layer, a request is sent from the RRC protocol layer to the MAC protocol layer to determine whether the small data transmission mode is permitted to be initiated at the MAC protocol layer. In response to the aforementioned request, it is determined that the small data transmission mode is permitted to be initiated at the MAC protocol layer, If the small data transmission mode is permitted to be initiated at the MAC protocol layer, then further instructions are sent from the MAC protocol layer to the RRC protocol layer. In response to the further instructions, the communication procedure for the small data transmission is initiated via the RRC protocol layer in accordance with the small data transmission mode. The terminal device according to claim 1, configured to cause the terminal device to perform the above.

4. The terminal device according to claim 1, wherein the at least one memory and the program code are configured to cause the terminal device to determine, using the at least one processor, that resources for the small data transmission are set up, thereby determining that the small data transmission is permitted to be initiated at the RRC protocol layer.

5. The terminal device according to claim 1, wherein the at least one memory and the program code are configured to cause the terminal device to determine, using the at least one processor, that resources for a small data transmission mode are set up, thereby determining that the small data transmission is permitted to be initiated at the RRC protocol layer.

6. The terminal device according to claim 1, wherein the at least one memory and the program code are configured to cause the terminal device to determine, using the at least one processor, that data is available in at least one wireless bearer authorized for the small data transmission, thereby determining that the small data transmission is permitted to be initiated at the RRC protocol layer.

7. The terminal device according to claim 1, wherein the at least one memory and the program code are configured to cause the terminal device to perform the following actions: determine, using the at least one processor, that the amount of data to be transmitted meets the requirements based on a data volume threshold set for the small data transmission, thereby determining that the small data transmission is permitted to be initiated at the RRC protocol layer.

8. The aforementioned small data transmission mode is as follows: Small data transmission mode based on configuration grant, Small data transmission mode based on random access procedure, A small data transmission mode based on a two-step random access procedure, and Small data transmission mode based on a 4-step random access procedure. The terminal device according to claim 3 or 5, comprising one of the following.

9. The terminal device according to claim 1, wherein the at least one memory and the program code are configured to cause the terminal device to determine, using the at least one processor, that the resources set out for the small data transmission are valid, thereby determining that the small data transmission is permitted to be initiated at the MAC protocol layer.

10. The terminal device according to claim 1, wherein the at least one memory and the program code are configured to cause the terminal device to determine, using the at least one processor, that the resources set for the small data transmission mode are valid, thereby determining that the small data transmission is permitted to be initiated at the MAC protocol layer.

11. The terminal device according to claim 1, wherein the at least one memory and the program code are configured to cause the terminal device to determine, using the at least one processor, that the amount of data to be transmitted meets the requirements based on a data volume threshold set for the small data transmission, thereby determining that the small data transmission is permitted to be initiated at the MAC protocol layer.

12. The terminal device according to claim 1, wherein the at least one memory and the program code are configured to cause the terminal device to determine, using the at least one processor, that the amount of data to be transmitted meets the requirements based on a data volume threshold set for the small data transmission mode, thereby determining that the small data transmission is permitted to be initiated at the MAC protocol layer.

13. The terminal device according to claim 1, wherein the at least one memory and the program code are configured to cause the terminal device to determine, using the at least one processor, that the channel quality between the terminal device and the network device meets the requirements based on the quality threshold set for the small data transmission, thereby determining that the small data transmission is permitted to be initiated at the MAC protocol layer.

14. The terminal device according to claim 1, wherein the at least one memory and the program code are configured to cause the terminal device to determine, using the at least one processor, that the channel quality between the terminal device and the network device meets the requirements based on a quality threshold set for the small data transmission mode, thereby determining that the small data transmission is permitted to be initiated at the MAC protocol layer.

15. The at least one memory and the program code are further processed using the at least one processor. Selecting one of several uplink carriers, Determining whether the small data transmission is permitted to be initiated on one of the multiple uplink carriers, The terminal device according to claim 1, configured to cause the terminal device to perform the above.

16. The at least one memory and the program code, using the at least one processor, further with respect to a given uplink carrier of the plurality of uplink carriers, Determining whether the channel quality between the terminal device and the network device across the given uplink carrier meets the requirements based on the quality threshold set for the small data transmission or small data transmission mode, If the channel quality meets the requirements based on the quality threshold, the given uplink carrier is selected. The terminal device according to claim 15, configured to cause the terminal device to perform the above.

17. The terminal device according to claim 1, wherein the at least one memory and the program code are further configured to cause the terminal device to perform the action of sending a request from the RRC protocol layer to the Packet Data Convergence Protocol (PDCP) protocol layer of the terminal device in order to resume the at least one wireless bearer for small data transmission, using the at least one processor.

18. The at least one memory and the program code are further processed using the at least one processor. If the small data transmission is rejected from being initiated at the RRC protocol layer or the MAC protocol layer, the further communication procedure for non-small data transmission with the network device is initiated via the RRC protocol layer. The terminal device according to claim 1, configured to cause the terminal device to perform the above.

19. A method for a terminal device that is performed while the terminal device is in an inactive state of radio resource control (RRC), Determining that small data transmission is permitted to be initiated at the RRC protocol layer of the terminal device, If the small data transmission is permitted to be initiated at the RRC protocol layer, then determine whether the small data transmission is permitted to be initiated at the Media Access Control (MAC) protocol layer of the terminal device. If the small data transmission is permitted to be initiated at the MAC protocol layer, the RRC protocol layer initiates the communication procedure for the small data transmission with the network device. Includes, The method further comprises, in response to an instruction from the MAC protocol layer that the small data transmission is permitted to be initiated at the MAC protocol layer, initiating the communication procedure for the small data transmission at the RRC protocol layer.

20. A computer-readable storage medium storing program instructions for causing a device to perform at least the method described in claim 19.

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