Initiation 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] FIELD Embodiments of the present disclosure relate generally to the field of telecommunications, and more particularly to a device, method, apparatus, and computer-readable storage medium for initiating small data transmission (SDT). [Background technology]

[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 may perform small data transmission (SDT) procedures with other communication devices, and does not need to establish a connection with the other communication devices. Summary of the Invention

[0003] Generally, the exemplary embodiments of the present disclosure provide a solution for initiating SDT. Any embodiments not falling within the scope of the claims should be construed as examples useful for understanding various embodiments of the present disclosure.

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

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

[0006] In a third aspect, a first device is provided, the first device comprising: means for determining whether small data transmission is permitted to be initiated at a first protocol layer of the first device; means for determining 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 means for initiating a communication procedure for small data transmission 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.

[0007] In a fourth aspect, there is provided a computer readable medium comprising program instructions for causing an apparatus to perform at least the method according to the first aspect.

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

[0009] Several exemplary embodiments will now be described with reference to the accompanying drawings. [Brief explanation of the drawings]

[0010] [Figure 1] 1 illustrates an exemplary communication environment in which exemplary embodiments of the present disclosure may be implemented. [Figure 2] 1 illustrates an exemplary protocol stack for a device in which exemplary embodiments of the present disclosure may be implemented. [Figure 3] 1 illustrates a signaling flow for SDT initiation between protocol layers of a device, according to some example embodiments of the present disclosure. [Figure 4] 1 illustrates a flowchart of a method implemented in a first device, according to some exemplary embodiments of the present disclosure. [Figure 5] FIG. 1 shows a simplified block diagram of a device suitable for practicing exemplary embodiments of the present disclosure. [Figure 6] 1 illustrates a block diagram of an exemplary computer-readable medium according to some exemplary embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

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

[0012] The principles of the present disclosure will now be described with reference to several exemplary embodiments. It should be understood that these embodiments are set forth for illustrative purposes only, to assist those skilled in the art in understanding and practicing the present disclosure, and are not intended to imply any limitation on the scope of the present disclosure. The embodiments described herein can be implemented in a variety of ways other than those described below.

[0013] In the following description and claims, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs, unless defined otherwise.

[0014] References in this disclosure to "one embodiment," "embodiment," "exemplary embodiment," and the like indicate that the described embodiment may include a particular feature, structure, or characteristic, but not every embodiment necessarily includes the particular feature, structure, or characteristic. Moreover, such phrases do not necessarily refer to the same embodiment. Furthermore, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is believed to be within the knowledge of one of ordinary skill in the art to use such feature, structure, or characteristic in connection with other embodiments, whether or not explicitly stated.

[0015] As used herein, terms such as "first" and "second" may be used to describe various elements, but it is understood that these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element, without departing from the scope of the exemplary embodiments. As used herein, the term "and / or" includes any and all combinations of one or more of the listed terms.

[0016] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. It will be further understood that the terms "comprises," "comprising," "has," "having," "includes," and / or "including," as used herein, specify the presence of stated features, elements, and / or components, etc., 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 implementations (e.g., analog and / or digital-only circuit implementations); (b) a combination of hardware circuitry and software, e.g., (where applicable); (i) a combination of analog and / or digital hardware circuitry(s) and software / firmware; and (ii) any portion of hardware processor(s) and software (including digital signal processor(s), software, and memory(s) that cooperate to cause a device, such as a mobile phone or server, to perform various functions); (c) processor(s), such as hardware circuit(s) and / or microprocessor(s) or portions of microprocessor(s), that require software (e.g., firmware) to operate, but may be free of software if not necessary for operation; and It may refer to one or more or all of:

[0018] This definition of circuit applies to all uses of the term in this application, including any claims. As a further example, the term circuit as used in this application encompasses implementations of just a hardware circuit or processor(s), or of portions of a hardware circuit or processor together with its (or their) accompanying software and / or firmware. The term circuit also encompasses, for example, a baseband or processor integrated circuit in a mobile device, or similar integrated circuit in a server, cellular network device, or other computing or network device, if applicable to certain claim elements.

[0019] As used herein, the term "communication network" refers to a network conforming to any suitable communication standard, such as New Radio (NR), Long Term Evolution (LTE), LTE-Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA), High-Speed ​​Packet Access (HSPA), and Narrowband Internet of Things (NB-IoT). Furthermore, communications between terminal devices and network devices in a communication network may be performed according to any suitable generation of communication protocols, including, but not limited to, first-generation (1G), second-generation (2G), 2.5G, 2.75G, third-generation (3G), fourth-generation (4G), 4.5G, fifth-generation (5G) communication protocols, and / or any other protocols currently known or developed in the future. Embodiments of the present disclosure may be applied to various communication systems. Given the rapid development in communications, it is understood that there will also be future communication technologies and systems in which the present disclosure can be embodied. The scope of the present disclosure should not be considered limited to only the aforementioned systems.

[0020] The term "network device" as used herein refers to a node in a communication network through which a terminal device accesses and receives services from the network. Depending on the terminology and technology applied, the network device may refer to a base station (BS) or an access point (AP), such as a Node B (Node B or NB), evolved Node B (eNode B or eNB), NR NB (also referred to as gNB), remote radio unit (RRU), radio header (RH), remote radio head (RRH), relay, integrated access backhaul (IAB) node, low-power nodes such as femto and pico, and non-terrestrial network (NTN) or non-terrestrial network devices such as satellite network devices, low Earth orbit (LEO) satellites and geostationary Earth orbit (GEO) satellites, and airborne network devices. In some exemplary embodiments, a Radio Access Network (RAN) split architecture comprises a centralized unit (CU) and a distributed unit (DU) in an IAB donor node. An IAB node comprises a mobile terminal (IAB-MT) portion that acts like a UE towards a parent node, and the DU portion of the IAB node acts like a base station towards the next-hop IAB node.

[0021] The term "terminal device" refers to any end device that may be capable of wireless communication. By way of example and not limitation, a terminal device may also be referred to as a communication device, user equipment (UE), subscriber station (SS), mobile subscriber station, mobile station (MS), or access terminal (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, gaming terminal devices, music storage and playback appliances, in-vehicle wireless terminal devices, wireless endpoints, mobile stations, laptop embedded equipment (LEE), laptop mounted equipment (LME), USB dongles, smart devices, wireless customer premises equipment (CPE), Internet of Things (IoT) devices, watches or other wearable devices, head-mounted displays (HMD), 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 and / or automated processing chain contexts), consumer electronics devices, and devices operating in commercial and / or industrial wireless networks. Terminal devices may also correspond to the mobile termination (MT) portion of an IAB node (e.g., a relay node). In the following description, 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, including time-domain resources, frequency-domain resources, spatial-domain resources, code-domain resources, or other resources that enable communication. In the following, to describe some exemplary embodiments of the present disclosure, both frequency-domain and time-domain resources 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] 1 illustrates an exemplary communication environment 100 in which exemplary embodiments of the present disclosure may be implemented. In the communication environment 100, multiple communication devices, including a first device 110 and a second device 120, may communicate with each other.

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

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

[0026] In some demonstrative 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 the DL, the second device 120 is the transmitting (TX) device (i.e., transmitter) and the first device 110 is the receiving (RX) device (i.e., receiver). In the UL, the first device 110 is the TX device (i.e., transmitter) and the second device 120 is the RX device (i.e., receiver).

[0027] Communications in communication environment 100 may be conducted according to any suitable communications protocol(s), including, but not limited to, cellular communications protocols such as first generation (1G), second generation (2G), third generation (3G), fourth generation (4G), and fifth generation (5G), wireless local network communications protocols such as Institute of Electrical and Electronics Engineers (IEEE) 802.11, and / or any other protocols now known or developed in the future. Further, communications may utilize any suitable wireless communications technology, including, but not limited to, code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), frequency division duplex (FDD), time division duplex (TDD), multiple input multiple output (MIMO), orthogonal frequency division multiplexing (OFDM), discrete Fourier transform spread OFDM (DFT-s-OFDM), and / or any other technology now known or developed in the future.

[0028] The first device 110 and the second device 120 may include a protocol stack having multiple protocol layers. FIG. 2 shows an example protocol stack for the first device 110. As shown, the protocol stack for 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. To facilitate communication between the first device 110 and other devices, each of the protocol layers may perform corresponding services and functions. Although not shown, the protocol stack for the first device 110 may include additional protocol layers in addition to the RRC, PDCP, and MAC layers. The 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. Communication between devices, such as between the first device 110 and the second device 120, typically occurs within the same protocol layers between the two devices. For example, a communication from the RRC layer 202 of the first device 110 is conveyed through the PDCP layer 204, the MAC layer 206, and sent via the PHY layer to the second device 120. When the communication is received at the second device 120, it is conveyed through the protocol layers of the second device 120 in 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 an inactive mode, an RRC_INACTIVE state / mode, and such terms are used interchangeably herein. The connected state may sometimes be referred to as a connected mode, an active state / mode, or an RRC_CONNECTED state / mode, and such terms are used interchangeably herein.

[0031] Typically, 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 incurs a certain amount of signaling overhead and power consumption. If connection setup and subsequent connection release occur for at least one data transmission of a terminal device in an inactive state, unnecessary power consumption and signaling overhead may occur, no matter how small or infrequent the data packets are. Currently, a terminal device in an inactive state may be capable of performing small data transmission (SDT). As used herein, the term "SDT" refers to a type of transmission in which a small amount of data is 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 (including, for example, periodic positioning information). In some applications on non-mobile devices, SDT may include sensor data (e.g., temperature and pressure measurements transmitted periodically or in an event-triggered manner over an IoT network), metering and alert information from smart meters, and / or the like.

[0033] The signaling overhead and delays incurred by inactive devices due to small data packets are a global issue that affects not only network performance and efficiency, but also battery performance. Typically, any device with intermittent small data packets in an inactive state would benefit from enabling SDT. Preferably, devices should apply some criteria for selecting SDT or 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 the selection between SDT and non-SDT is made at different protocol layers of a device.

[0034] According to some exemplary embodiments of the present disclosure, a solution for initiating an SDT procedure is provided, in which permission to start an SDT is checked at different protocol layers. If it is determined that the SDT is allowed to start, the SDT communication procedure is initiated. With this solution, permission to start an SDT is further checked at other layers before the protocol layer decides to start the SDT.

[0035] By dividing the SDT initiation criteria among different protocol layers, each protocol layer can focus on its own relevant services and functions related to SDT. Various combinations of SDT initiation criteria are also possible among protocol layers. Furthermore, considering that some SDT-allowed radio bearers can be resumed in a situation where an SDT procedure can be initiated, it is beneficial to define an optimal division of criteria checks among protocol layers. This not only avoids incorrect resumption of radio bearers when an SDT procedure cannot be performed, but also avoids unnecessary interactions between protocol layers.

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

[0037] Reference is now made to Figure 3, which illustrates a signaling flow 300 for SDT initiation, in accordance with some example embodiments of the present disclosure. The signaling flow 300 may include operations and interactions between different protocol layers of the first device 110. For purposes of discussion, reference is made to the communication environment illustrated in Figure 1 and the protocol stacks illustrated in Figure 2.

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

[0039] Specifically, the first device 110 determines (302) whether initiation of an SDT is permitted (or available) at a first protocol layer, e.g., an upper layer, the RRC layer 202. Initiation of an SDT is triggered at the first device 110 when certain predetermined criteria are met. According to an embodiment 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 the RRC layer 202 determines that initiation of SDT is permitted (or available), e.g., if it determines that the criteria set in the RRC layer 202 are satisfied, the first device 110, instead of directly resuming the radio bearers configured for SDT, determines whether initiation of SDT is permitted (304) at a second protocol layer, e.g., a lower layer, the MAC layer 206. According to an embodiment of the present disclosure, one or more criteria are checked at the MAC layer 206 to determine whether initiation of SDT is permitted.

[0041] In some example embodiments, if the RRC layer 202 determines that initiation of SDT is permitted, the RRC layer 202 may send a request to the MAC layer 206 to determine whether 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 permission to initiate SDT are met.

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

[0043] In some exemplary embodiments, because the MAC layer 206 also determines that SDT is permitted, the RRC layer 202 may determine to perform an SDT RRC resume on the SDT radio bearers to initiate SDT communication procedures (306A). The radio bearers to resume for SDT may include a signaling radio bearer (SRB), e.g., SRB1 or SRB2, and a data radio bearer (DRB) for SDT. In an exemplary embodiment, the RRC layer 202 may resume SRB1 or SRB2 for SDT. In an exemplary embodiment, the RRC layer 202 may send a request to the PDCP layer 204 to resume at least one radio bearer (e.g., an SRB or DRB) for SDT (307). In some exemplary embodiments, after resuming the radio bearers, the PDCP layer 204 may inject data for transmission to lower layers, such as the RLC layer, for further processing by the MAC layer 206 (309). In some demonstrative 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 a conventional protocol stack, if the RRC layer of a device determines that it can initiate SDT communication with another device, the RRC layer may directly resume radio bearers, such as DRBs and / or SRBs. If the MAC layer finds that the SDT is unavailable, e.g., resources for the SDT are invalid, an erroneously resumed radio bearer can cause complex problems in the protocol stack. According to an exemplary embodiment of the present disclosure, by checking permission to start an SDT at both the RRC layer and the MAC layer, it is possible to avoid erroneous resumption of a radio bearer if the MAC layer finds that the SDT is unavailable, which would have resulted in unnecessary interaction between protocol layers if the radio bearer were erroneously resumed.

[0045] Some detailed examples of SDT initiation authorization criteria split between the RRC layer 202 and the MAC layer 206 are discussed below. To better understand the discussed criteria, some 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). Accordingly, two or more different SDT modes may be defined based on the resource type (e.g., RA resources or CG resources) used for the SDT procedure. In some examples, an SDT mode based on the RA procedure may be referred to as an RA-based SDT mode or an RA-SDT mode. An SDT mode that uses a CG for data communication may be referred to as a CG-based SDT mode or a CG-SDT mode. In the RA-based SDT mode, data may be transmitted from the first device 110 to the second device 120 in Msg A of a two-step RA procedure or in Msg 3 of a four-step RA procedure. In the CG-based SDT mode, data transmission(s) may be performed directly using resources of the CG, e.g., resources of a configured grant type 1.

[0047] In some demonstrative embodiments, since the RA procedure may include a two-step RA procedure or a four-step RA procedure, there may be different RA-based SDT modes, i.e., an SDT mode using a two-step RA procedure and an SDT mode using a four-step RA procedure. The RA-based SDT mode based on two-step RA resources may be referred to as a two-step RA-based SDT mode, and the RA-based SDT mode based on four-step RA resources 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 Msg A 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 Msg 3 of the four-step RA procedure initiated with the second device 120.

[0048] In some exemplary embodiments of the present disclosure, several SDT modes are described, but it will be understood that other applicable SDT modes may exist. In some exemplary embodiments, multiple different SDT modes may be defined based on a specific number or range of numbers of consecutive data transmissions allowed in the SDT procedure. For example, an 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 302 whether SDT is allowed at the RRC layer 202, the RRC layer 202 may apply a radio bearer data availability-based criterion to SDT. In some example embodiments, the RRC layer 202 may determine whether one or more radio bearers for which SDT is allowed exist and whether data is available on at least one radio bearer for which SDT is allowed. In some cases, not all radio bearers are configured for SDT. If the RRC layer 202 determines that no data is available on the radio bearer(s) for SDT, the RRC layer 202 may determine that SDT is not allowed. If it determines that such data is present, the RRC layer 202 may determine that the radio bearer data availability-based criterion is 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. The threshold-based criteria may include criteria based on a data volume threshold configured for SDT. The RRC layer 202 may determine whether the amount of data to be transmitted meets a requirement based on the data volume threshold configured for SDT. In some exemplary embodiments, the requirement may not be specific to an SDT mode but may be common to SDT, and the data volume threshold for SDT may be configured in the RRC layer 202. The requirement for SDT may be defined as being met if the amount of data to be transmitted is less than or equal to (or strictly below) the data volume threshold. In this case, the RRC layer 202 may determine whether to allow the start 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 the one or more SDT modes may be configured in the RRC layer 202. The requirement for initiating an SDT mode may be satisfied if the data volume threshold specific to the SDT mode is met. For example, a first data volume threshold may be configured for the first SDT mode, and a second data volume threshold may be configured for the 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 to be transmitted is less than or equal to the first data volume threshold for the first SDT mode, the first SDT mode may be selected for initiation. In some exemplary embodiments, if the first device 110 can determine that the amount of data to be transmitted exceeds the first data volume threshold and is less than or equal to the second data volume threshold for 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 the data volume threshold-based criteria, the 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, the channel quality may be measured based on one or more of the 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 the signal-to-interference-and-noise ratio (SINR) or path loss. The RRC layer 202 may determine whether the channel quality meets requirements based on the channel quality threshold set for SDT. In some exemplary embodiments, the requirements may be common to SDT rather than specific to the SDT mode, and the channel quality threshold for SDT may be set in the RRC layer 202. It may be defined that the requirements for SDT are met if the channel quality exceeds the channel quality threshold. In this case, the RRC layer 202 may determine whether SDT initiation is permitted by comparing the channel quality to a channel quality threshold. In some exemplary embodiments, similar to the data volume threshold-based criteria, one or more channel quality thresholds specific to one or more SDT modes may be configured in the RRC layer 202. By comparing the channel quality to the SDT mode-specific thresholds, the RRC layer 202 may determine the SDT mode(s) that may be permitted to initiate.

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

[0054] In some exemplary embodiments, the RRC layer 202 may not determine the validity of resources configured for SDT. Verification of resources configured for SDT may be performed by the MAC layer 206. As indicated above, the SDT communication procedure is initiated by the RRC layer 202 after the MAC layer 206 also verifies that SDT is permitted. Thus, it is possible to prevent the RRC layer 202 from initiating a communication procedure when valid resources do not exist.

[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 to determine whether an RA procedure or a CG-based procedure should be initiated, and therefore the criteria applied by the RRC layer 202 may not be SDT mode specific, but rather generic to all possible SDT modes.

[0056] In some example embodiments, the RRC layer 202 may be able to determine which one or more SDT modes may be allowed after applying criteria of the RRC layer 202. For example, the RRC layer 202 may be configured with one or more data volume-based criteria or channel quality-based criteria that are specific to one or more SDT modes, such as a CG-based SDT mode, an RA-based SDT mode, a 2-step-based SDT mode, or a 4-step-based SDT mode, etc. In this case, if any of the criteria is met, the RRC layer 202 may determine that entry of the corresponding SDT mode(s) is allowed.

[0057] In some example embodiments, the RRC layer 202 may perform checks based on criteria that are independent of the selection of the SDT mode or the selection of the UL carrier (e.g., a normal UL carrier or a supplemental UL (SUL) carrier).

[0058] Various criteria for the RRC layer 202 are discussed above. It will be appreciated that the RRC layer 202 may apply one or more of the above criteria and / or other possible criteria to determine SDT authorization. The scope of the present disclosure is not limited in this respect.

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

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

[0061] A radio bearer data availability-based criterion may be applied to the SDT to determine 304 whether the RRC layer 202 is allowed. In some exemplary embodiments, if there are no modes specified for the SDT, the RRC layer 202 may determine whether initiation of the SDT is allowed. In some exemplary embodiments, the MAC layer 206 may determine initiation permission for one or more SDT modes configured for the first device 110. As noted above, in some exemplary embodiments, the SDT mode may be indicated by the RRC layer 202.

[0062] In some exemplary embodiments, first device 110 may be configured with multiple UL carriers (such as a normal UL carrier or an SUL carrier) for communication with second device 120. In such a case, MAC layer 206 may select one of the UL carriers for communication. In some exemplary embodiments, UL carrier selection may follow a legacy selection mechanism unrelated to SDT. In exemplary embodiments, UL carrier selection 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 may be set in the MAC layer 206, which may differ from the threshold used in the legacy selection mechanism. To select a UL carrier, the MAC layer 206 may determine whether the channel quality over a given UL carrier meets a requirement based on the channel quality threshold set for SDT. In some examples, the requirement may be met if the channel quality over a given UL carrier exceeds a particular channel quality threshold. In this case, the MAC layer 206 may select the given UL carrier.

[0064] Once a UL carrier is selected, the MAC layer 206 may apply further criteria, if any, to determine whether SDT is permitted to begin on the selected UL carrier. In some exemplary embodiments, the MAC layer 206 may apply resource availability-based criteria for SDT. The MAC layer 206 may determine whether resources are configured and available for SDT or whether resources are configured and available for a particular SDT mode.

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

[0066] In some exemplary embodiments, if RA resources are configured for the first device 110, the MAC layer 206 may further determine whether the RA resources are 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 resources may include, for example, a physical random access channel (PRACH) and preamble, as well as dedicated radio resources for the RA procedure for SDT.

[0067] In some example embodiments, by checking the availability of CG and / or RA resources, the MAC layer 206 may be able to determine whether initiation of a CG-based SDT mode or an RA-based SDT mode (e.g., a 2-step RA-based SDT mode or a 4-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. The threshold-based criteria may include criteria based on a data volume threshold configured for SDT and criteria based on a channel quality threshold configured for SDT. In some exemplary embodiments, if the MAC layer 206 is configured with threshold-based criteria, it may be unnecessary for the RRC layer 202 to perform threshold-based criteria checks for SDT. In some exemplary embodiments, both the RRC layer 202 and the MAC layer 206 may perform threshold-based criteria checks for SDT, although different thresholds may be configured for the two layers.

[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 a data volume threshold configured for SDT or may include requirements based on one or more data volume thresholds configured specifically for one or more SDT modes. In some exemplary embodiments, the criteria based on channel quality thresholds may include requirements based on a channel quality threshold configured for SDT or may include requirements based on one or more channel quality thresholds configured specifically for one or more SDT modes. By comparing the amount of data to be transmitted with the corresponding data volume threshold(s) and / or comparing the channel quality with the corresponding channel quality threshold(s), the MAC layer 206 may determine whether SDT is allowed or which SDT mode is allowed. In some exemplary embodiments, SDT is allowed if both the criteria based on data volume thresholds and channel quality thresholds are met.

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

[0071] In the above embodiment, the operation of the protocol layer when it is determined that SDT is permitted has been described. In some cases, if the RRC layer 202 or the MAC layer 206 determines that SDT is rejected, for example, if one or more criteria in the RRC layer 202 or the MAC layer 206 are not met, the first device 110 may initiate a non-SDT communication procedure with the second device 120. Continuing with FIG. 2 , for example, if the RRC layer 202 determines that SDT is rejected because no resources or radio bearers configured or permitted for SDT exist, the 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, the RRC layer 202 may decide to resume an SBR, e.g., SBR1, for the non-SDT communication procedure. The RRC layer 202 may further send a CCCH RRC resume request for non-SDT to the MAC layer 206 (308B). The PDCP layer 204 and the MAC layer 206 may operate appropriately to perform non-SDT communication procedures, in which data may be transmitted to the second device 120 using the non-SDT procedures.

[0072] If the RRC layer 202 determines that SDT is allowed, but the MAC layer 206 determines that SDT initiation is not allowed, the MAC layer 206 may send an indication of SDT initiation denial or unavailability to the RRC layer 202 (305B). Upon receiving such an indication from the MAC layer 206, the RRC layer 202 may initiate non-SDT communication procedures in response (306B).

[0073] The interactions between protocol layers have been discussed above. Exemplary procedures performed at the MAC layer 206 according to some exemplary embodiments may be summarized as follows: The corresponding steps of signaling flow 300 are shown below. - When the MAC receives a request to start an SDT procedure (step 303), it performs SUL / UL selection (step 304) based on the SUL / UL_SDT_RSRP threshold (which may be the same as or different from the conventional SUL / UL RSRP threshold). - After selecting the UL carrier (step 304), - The MAC performs CG verification (including TA, beam, RSRP criteria, etc.) for the selected UL carrier (step 304); - If there is a valid CG in the SDT, - MAC indicates to RRC that it can start the (CG-)SDT and executes the CG-SDT (step 305A), - If no valid CG exists (is not configured or does not meet any criteria), - the MAC checks the availability of 2-step and 4-step RA-SDT and performs 2-step / 4-step RA selection based on a 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 is a valid RA resource in the SDT for the selected RA type, - the MAC indicates to the RRC that it can start the (RA-)SDT and therefore performs the RA-SDT (step 305A); - if there is neither a CG valid for SDT nor a 2-step or 4-step RA resource valid for SDT on the selected UL (note that it is conceivable that the first device 110 may be configured with only a CG-SDT resource without an RA-SDT, or with only a 2-step RA or a 4-step RA configured for SDT) (step 304); - The MAC indicates to the RRC that it is not possible to perform the SDT procedure (step 305B).

[0074] Exemplary procedures performed in the RRC layer 202 according to some exemplary embodiments may be summarized as follows: The corresponding steps of the signaling flow 300 are shown below. - if the SDT criteria are met, e.g. whether SDT is configured for the associated DRB and whether the UL payload complies with the SDT threshold, and whether the SDT-RSRP criteria are met (step 302); - requesting the MAC to perform SDT resource verification (step 303); - if an SDT available indication is received from the MAC (step 305A), - Resume SRB1 / (SRB2) / SDT DRB(s) (steps 307 and 308A), - Execute SDT resume and send SDT resume to MAC (steps 306A and 309), - if an unavailability indication is received from the MAC (step 305B), - Resume SRB1, - Execute a non-SDT resume (steps 306B and 308B).

[0075] 4 shows a flowchart of an example method 400 implemented at the first device 110, according to some example embodiments of the present disclosure. For discussion purposes, the method 400 will be described from the perspective of the first device 110 with respect to FIG.

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

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

[0078] In some demonstrative embodiments, the first device 110 may determine that SDT is allowed to start 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 for which SDT is allowed; or the amount of data to be transmitted meets a requirement based on a first data amount threshold set for SDT.

[0079] In some example embodiments, the at least one SDT mode includes at least one of the following: a first SDT mode based on a configuration 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 demonstrative embodiments, if initiation of SDT is allowed at the first protocol layer, the first device 110 may cause one of the following requests to be sent from the first protocol layer to the second protocol layer: a first request to determine whether initiation of SDT is allowed at the second protocol layer; or a second request to determine whether initiation of the target SDT mode is allowed at the second protocol layer.

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

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

[0083] In some demonstrative embodiments, if the second protocol layer allows initiation of one of the at least one SDT mode, the first device 110 may cause an indication of the determined SDT mode to be transmitted from the second protocol layer to the first protocol layer, and in response to the indication of the determined SDT mode, the first device 110 may initiate an SDT communication procedure by initiating a communication procedure according to the determined SDT mode via the first protocol layer.

[0084] In some demonstrative embodiments, the first device 110 may determine that SDT is allowed to start at the second protocol layer by determining that at least one of the following criteria is met: resources configured for SDT are valid; resources configured for at least one SDT mode are valid; the amount of data to be transmitted meets a requirement based on a second data volume threshold set for SDT; the amount of data to be transmitted meets a requirement 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 a requirement based on a first quality threshold set for SDT; or the channel quality meets a requirement based on a second quality threshold set for at least one SDT mode.

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

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

[0087] In some exemplary embodiments, the first device 110 may initiate a communication procedure for the SDT 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 a third protocol layer (e.g., PDCP layer 204) of the first device 110. In some exemplary embodiments, the third protocol layer includes a packet data convergence protocol layer.

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

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

[0090] In some exemplary embodiments, the means for determining whether initiation of small data transmission is permitted at the first protocol layer comprises means for determining that 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 for which small data transmission is permitted; or the amount of data to be transmitted meets a requirement based on a first data amount threshold set for small data transmission.

[0091] In some exemplary embodiments, the at least one small data transmission mode includes at least one of the following: a first small data transmission mode based on a configuration 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 demonstrative embodiments, the first device further comprises means for causing, in accordance with a determination that initiation of small data transmission is permitted at the first protocol layer, one of the following requests to be sent from the first protocol layer to the second protocol layer: a first request to determine whether initiation of small data transmission is permitted at the second protocol layer; or a second request to determine whether initiation of a target small data transmission mode is permitted at the second protocol layer.

[0093] In some exemplary embodiments, the means for determining whether initiation of small data transmission at the second protocol layer is permitted includes means for determining whether initiation of small data transmission at the second protocol layer is permitted in response to a first request, or means for determining whether 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, the means for determining whether initiation of small data transmission at the second protocol layer is permitted includes means for determining whether 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 comprises means for causing, in accordance with a determination that initiation of one of the at least one small data transmission modes is permitted at the second protocol layer, an indication of the determined small data transmission mode to be sent from the second protocol layer to the first protocol layer. In some exemplary embodiments, the means for initiating a small data transmission communication procedure includes means for initiating a communication procedure according to the determined small data transmission mode via the first protocol layer in response to the indication of the determined small data transmission mode.

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

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

[0098] In some demonstrative embodiments, the means for selecting one of the plurality of uplink carriers includes: means for determining, for a given uplink carrier of the plurality of uplink carriers, whether a channel quality over the given uplink carrier meets a requirement based on a fourth quality threshold configured for the small data transmission or a requirement based on a fifth quality threshold configured for the small data transmission mode; and means for selecting the given uplink carrier according to a determination that the channel quality meets the requirement based on the fourth quality threshold or the requirement based on the fifth quality threshold.

[0099] In some exemplary embodiments, the means for initiating a communication procedure for the small data transmission via the first protocol layer includes means for causing the first protocol layer to send a third request to a third protocol layer of the first device to resume at least one radio bearer for the 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 layer includes a medium access control layer.

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

[0102] In some exemplary embodiments, the first apparatus further comprises means for performing method 400 or other operations in some exemplary embodiments of 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 configured to cause execution of the first apparatus using the at least one processor.

[0103] 5 is a simplified block diagram of a device 500 suitable for implementing an exemplary embodiment of the present disclosure. Device 500 may be provided to implement a communications device such as first device 110 or second device 120 shown in FIG. 1. As shown, device 500 includes one or more processors 510, one or more memories 520 coupled to processor 510, and one or more communications modules 540 coupled to processor 510.

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

[0105] The processor 510 may be of any type suitable for a local technical network, including, by way of non-limiting example, one or more of a general-purpose computer, a special-purpose computer, a microprocessor, a digital signal processor (DSP), and a processor based on a multi-core processor architecture. The device 500 may have multiple processors, such as application-specific integrated circuit chips configured to time-track clocks that synchronize the main processors.

[0106] The 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 disks (CDs), digital video disks (DVDs), optical disks, laser disks, 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 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 a memory, for example, the ROM 524. The processor 510 may load the program 530 into the RAM 522 to perform any suitable operation or process.

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

[0109] In some exemplary embodiments, the program 530 may be tangibly contained in a computer-readable medium that may be included in the device 500 (such as the memory 520) or in other storage accessible by the device 500. The device 500 may load the program 530 from the computer-readable medium into the RAM 522 for execution. The computer-readable medium may include any type of tangible non-volatile storage device, such as a ROM, an EPROM, a flash memory, a hard disk, a CD, and a 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 disk. The computer-readable medium has the program 530 stored thereon.

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

[0111] 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, e.g., included in program modules, that, when executed on a target physical or virtual processor device, perform any of the methods described above with reference to Figures 3-4. Typically, program modules include routines, programs, libraries, objects, classes, components, or data structures that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split among program modules as desired in various embodiments. The machine-executable instructions of the program modules may be executed in local or distributed devices. In distributed devices, program modules are located in both local and remote storage media.

[0112] Program code for carrying out the methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus such that, when executed by the processor or controller, the program code performs the functions / acts specified in the flowcharts and / or block diagrams. The program code may be executed entirely on the machine, partially on the machine, as a stand-alone 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 the present disclosure, computer program code or associated data may be carried by any suitable carrier to enable a device, apparatus, or processor to perform the various processes and operations described above. Examples of carriers include signals, computer-readable media, etc.

[0114] The computer-readable medium may be a computer-readable signal medium or a computer-readable storage medium. The computer-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. More specific examples of the computer-readable storage medium include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0115] Furthermore, although operations are depicted in a particular order, this should not be understood as requiring such operations to be performed in the particular order or sequential order shown, or that all of the illustrated operations be performed, to achieve desirable results. Multitasking and parallel processing may be advantageous in certain situations. Similarly, while the above discussion includes details of several specific implementations, these should not be construed as limitations on the scope of the disclosure, but rather as descriptions of features that may be unique to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable subcombination.

[0116] Although the present disclosure has been described in language specific to structural features and / or methodological acts, it is to be understood that the present disclosure, as defined by the appended claims, is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. at least one processor; at least one memory containing computer program code; a first device comprising: The at least one memory and the computer program code are used by the at least one processor to: determining whether a small data transmission is permitted to be initiated at a first protocol layer of the first device; determining whether the small data transmission is permitted to be initiated at a second protocol layer of the first device in accordance with determining that the small data transmission is permitted to be initiated at the first protocol layer; Initiating a communication procedure for the small data transmission with a second device via the first protocol layer in accordance with a determination that the small data transmission is permitted to be initiated at the second protocol layer; The first device is configured to cause the first device to execute the

2. The at least one memory and the computer program code, using the at least one processor, are configured to: resources for the 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 authorized for the small data transmission; or the amount of data to be transmitted meets a requirement based on a first data amount threshold set for the small data transmission; The first device of claim 1, configured to cause the first device to determine that the small data transmission is permitted to be initiated at the first protocol layer by determining that at least one of the following is satisfied.

3. At least one small data transmission mode is one of the following: a first small data transmission mode based on a configuration 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; The first device of claim 2 , comprising at least one of:

4. The at least one memory and the computer program code, using the at least one processor, further In accordance with a determination that the small data transmission is permitted to be initiated at the first protocol layer, the following request: a first request to determine whether the small data transmission is permitted to be initiated at the second protocol layer; or a second request to determine whether a target small data transmission mode is allowed to be initiated at the second protocol layer; 2. The first device of claim 1, configured to cause the first device to perform one of the following:

5. The at least one memory and the computer program code are used by the at least one processor to: determining whether the small data transmission is permitted to be initiated at the second protocol layer in response to the first request; or determining, in response to the second request, whether the target small data transmission mode is permitted to be initiated at the second protocol layer; The first device of claim 4 , configured to cause the first device to execute:

6. 2. The first device of claim 1, wherein the at least one memory and the computer program code are configured to cause the first device, using the at least one processor, to determine whether at least one small data transmission mode is allowed to be initiated in the second protocol layer.

7. The at least one memory and the computer program code, using the at least one processor, further configured to cause the first device to, in accordance with a determination that one of the at least one small data transmission modes is permitted to be initiated at the second protocol layer, send an indication of the determined small data transmission mode from the second protocol layer to the first protocol layer; The at least one memory and the computer program code are used by the at least one processor to: initiating the communication procedure in accordance with the determined small data transmission mode via the first protocol layer in response to the indication of the determined small data transmission mode; The first device according to claim 6 , configured to cause the first device to initiate the communication procedure for the small data transmission.

8. The at least one memory and the computer program code, using the at least one processor, are configured to: that the resources configured for the small data transmission are valid; that resources configured for at least one small data transmission mode are available; the amount of data to be transmitted meets a requirement based on a second data amount threshold set for the small data transmission; the amount of data to be transmitted meets a requirement based on a third data amount threshold set for at least one small data transmission mode; The channel quality between the first device and the second device meets a requirement based on a first quality threshold set for the small data transmission; or the channel quality meets a requirement based on a second quality threshold set for at least one small data transmission mode; The first device of claim 1, configured to cause the first device to determine that the small data transmission is permitted to be initiated at the second protocol layer by determining that at least one of the following is satisfied.

9. The at least one memory and the computer program code are used by the at least one processor to: selecting one of a plurality of uplink carriers; determining whether the small data transmission is permitted to be initiated on the selected uplink carrier; The first device of claim 1 , configured to cause the first device to execute:

10. The at least one memory and the computer program code are configured to, using the at least one processor, perform, for a given uplink carrier of the plurality of uplink carriers: determining whether the channel quality across the given uplink carrier meets a requirement based on a fourth quality threshold set for the small data transmission or a requirement based on a fifth quality threshold set for the small data transmission mode; selecting the given uplink carrier in accordance with a determination that the channel quality meets the requirement based on the fourth quality threshold or the requirement based on the fifth quality threshold; The first device of claim 9 , configured to cause the first device to execute:

11. 2. The first device of claim 1, wherein the at least one memory and the computer program code are configured to cause the first device, using the at least one processor, to send a third request from the first protocol layer to a third protocol layer of the first device to resume at least one radio bearer for the small data transmission.

12. The first device of claim 11 , wherein the third protocol layer comprises a packet data convergence protocol layer.

13. The first device of claim 1 , wherein the first protocol layer includes a radio resource control layer and the second protocol layer includes a medium access control layer.

14. The at least one memory and the computer program code, using the at least one processor, further initiating a further communication procedure with the second device via the first protocol layer, the non-small data transmission, in accordance with a determination that the small data transmission is rejected from being initiated at the first protocol layer or the second protocol layer; The first device of claim 1 , configured to cause the first device to execute:

15. The first device of claim 1 , wherein the first device comprises a terminal device and the second device comprises a network device.

16. 1. A method comprising: determining, at a first device, whether a small data transmission is permitted to be initiated at a first protocol layer of the first device; determining whether the small data transmission is permitted to be initiated at a second protocol layer of the first device in accordance with determining that the small data transmission is permitted to be initiated at the first protocol layer; Initiating a communication procedure for the small data transmission with a second device via the first protocol layer in accordance with a determination that the small data transmission is permitted to be initiated at the second protocol layer; The method comprising:

17. 1. A first device, comprising: means for determining whether a small data transmission is permitted to be initiated at a first protocol layer of the first device; means for determining whether the small data transmission is permitted to be initiated at a second protocol layer of the first device in accordance with a determination that the small data transmission is permitted to be initiated at the first protocol layer; means for initiating a communication procedure for the small data transmission with a second device via the first protocol layer in accordance with a determination that the small data transmission is permitted to be initiated at the second protocol layer; The first device comprising:

18. A computer readable medium comprising program instructions for causing an apparatus to perform at least the method of claim 16.

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