WO2023216271A1

WO2023216271A1 - Method and apparatus for small data transmission

Info

Publication number: WO2023216271A1
Application number: PCT/CN2022/092884
Authority: WO
Inventors: Samuli Heikki TURTINEN; Chunli Wu; Jussi-Pekka Koskinen
Original assignee: Nokia Shanghai Bell Co., Ltd.; Nokia Solutions And Networks Oy; Nokia Technologies Oy
Priority date: 2022-05-13
Filing date: 2022-05-13
Publication date: 2023-11-16

Abstract

Embodiments of the present disclosure relate to small data transmission. A terminal device determine any one of the following conditions is met: transmission of message 3, Msg3, in a random access, RA, procedure, transmission of message A, MsgA, in a RA procedure, or receipt of a first response from a network device to a configured grant transmission for a configured grant (CG) -SDT procedure; and restart a timer for a small data transmission, SDT, procedure while the timer is already running. The solution for SDT as provided in the present disclosure can keep the synchronization for the timer between terminal device and the network device.

Description

METHOD AND APPARATUS FOR SMALL DATA TRANSMISSION

FIELD

Embodiments of the present disclosure generally relate to the field of telecommunication and in particular, to a method, device, apparatus and computer readable storage medium for small data transmission (SDT) .

BACKGROUND

For a terminal device in a radio resource control (RRC) idle mode or a RRC inactive mode, signals for transitioning to a RRC connected mode and maintaining the RRC connected mode may cause large overheads (e.g., power consumption and delay) when it has small amount of data (small data) to be transmitted.

With developments of communication systems, SDT technologies have been proposed to reduce the signaling overhead and delay by avoiding transiting to RRC connected mode. New Radio (NR) system supports both random access channel (RACH) based SDT (i.e., RA-SDT) and configured grant (CG) based SDT (i.e. CG-SDT) . In an RA-SDT procedure, a terminal device is enabled to transmit small data in the RRC inactive mode using an uplink grant received via a random access (RA) procedure for SDT. In a CG-SDT procedure, the terminal device is enabled to transmit small data in the RRC inactive mode using uplink resources pre-configured.

SUMMARY

In general, example embodiments of the present disclosure provide a solution for small data transmission.

In a first aspect, there is provided a terminal device. The terminal device comprises one or more transceivers; and one or more processers communicatively coupled to the one or more transceivers, and configured to cause the terminal device to: determine any one of the following conditions is met: transmission of message 3, Msg3, in a random access, RA, procedure, transmission of message A, MsgA, in a RA procedure, or receipt of a first response from a network device to a configured grant transmission for a configured grant (CG) -SDT procedure; and restart a timer for a small data transmission, SDT, procedure while the timer is already running.

In a second aspect, there is provided a method implemented at a terminal device. The method comprises determining any one of the following conditions is met: transmission of message 3, Msg3, in a random access, RA, procedure, transmission of message A, MsgA, in a RA procedure, or receipt of a first response from a network device to a configured grant transmission for a configured grant (CG) -SDT procedure; and restarting a timer for a small data transmission, SDT, procedure while the timer is already running.

In a third aspect, there is provided a terminal device. The terminal device comprises one or more processor; and one or more memories including computer program codes; wherein the one or more memories and the computer program codes are configured to, with the one or more processors, cause the terminal device to: determine any one of the following conditions is met: transmission of message 3, Msg3, in a random access, RA, procedure, transmission of message A, MsgA, in a RA procedure, or receipt of a first response from a network device to a configured grant transmission for a configured grant (CG) -SDT procedure; and restart a timer for a small data transmission, SDT, procedure while the timer is already running.

In a fourth aspect, there is provided an apparatus comprising means for means for determining any one of the following conditions is met: transmission of message 3, Msg3, in a random access, RA, procedure, transmission of message A, MsgA, in a RA procedure, or receipt of a first response from a network device to a configured grant transmission for a configured grant (CG) -SDT procedure; and means for restarting a timer for a small data transmission, SDT, procedure while the timer is already running.

In a fifth aspect, there is provided a non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the method according to the above second aspect.

It is to be understood that the summary section is not intended to identify key or essential features of 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 become easily comprehensible through the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

Some example embodiments will now be described with reference to the accompanying drawings, where:

Fig. 1 illustrates an example communication network in which embodiments of the present disclosure may be implemented;

Fig. 2 illustrates a signaling chart illustrating a process for small data transmission according to some embodiments of the present disclosure;

Fig. 3 illustrates a signaling chart illustrating a process for small data transmission according to some embodiments of the present disclosure;

Fig. 4 illustrates a signaling chart illustrating a process for small data transmission according to some embodiments of the present disclosure;

Fig. 5 illustrates a signaling chart illustrating a process for small data transmission according to some embodiments of the present disclosure;

Fig. 6 illustrates a flowchart of a method for STD implemented at a terminal device according to some embodiments of the present disclosure;

Fig. 7 illustrates a simplified block diagram of an apparatus that is suitable for implementing embodiments of the present disclosure; and

Fig. 8 illustrates a block diagram of an example computer readable medium in accordance with some embodiments of the present disclosure.

Throughout the drawings, the same or similar reference numerals represent the same or similar element.

DETAILED DESCRIPTION

Principle of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. The disclosure described herein can be implemented in various manners other than the ones described below.

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

References in the present disclosure to “one embodiment, ” “an embodiment, ” “an example embodiment, ” and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

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

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

As used in this application, the term “circuitry” may refer to one or more or all of the following:

(a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and

(b) combinations of hardware circuits and software, such as (as applicable) :

(i) a combination of analog and/or digital hardware circuit (s) with software/firmware and

(ii) any portions of hardware processor (s) with software (including digital signal processor (s) ) , software, and memory (ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and

(c) hardware circuit (s) and or processor (s) , such as a microprocessor (s) or a portion of a microprocessor (s) , that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and/or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

As used herein, the term “communication network” refers to a network following any suitable communication standards, such as Long Term Evolution (LTE) , LTE-Advanced (LTE-A) , Wideband Code Division Multiple Access (WCDMA) , High-Speed Packet Access (HSPA) , Narrow Band Internet of Things (NB-IoT) and so on. Furthermore, the communications between a terminal device and a network device in the communication network may be performed according to any suitable generation communication protocols, including, but not limited to, the third generation (3G) , the fourth generation (4G) , 4.5G, the future fifth generation (5G) communication protocols, and/or beyond. Embodiments of the present disclosure may be applied in various communication systems. Given the rapid development in communications, there will of course also be future type communication technologies and systems with which the present disclosure may be embodied. It should not be seen as limiting the scope of the present disclosure to only the aforementioned system.

As used herein, the term “network device” refers to a node in a communication network via which a terminal device accesses the network and receives services therefrom. The network device may refer to a base station (BS) or an access point (AP) , for example, a node B (NodeB or NB) , an evolved NodeB (eNodeB or eNB) , a NR NB (also referred to as a gNB) , a Remote Radio Unit (RRU) , a radio header (RH) , a remote radio head (RRH) , an Integrated Access and Backhaul (IAB) node, a relay, a low power node such as a femto, a pico, and so forth, depending on the applied terminology and technology.

The term “terminal device” refers to any end device that may be capable of wireless communication. By way of example rather than limitation, a terminal device may also be referred to as a communication device, user equipment (UE) , a Subscriber Station (SS) , a Portable Subscriber Station, a Mobile Station (MS) , or an Access Terminal (AT) . The terminal device may include, but not limited to, a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones, a tablet, a wearable terminal device, a personal digital assistant (PDA) , portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE) , laptop-mounted equipment (LME) , USB dongles, smart devices, wireless customer-premises equipment (CPE) , an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD) , a vehicle, a drone, a medical device and applications (e.g., remote surgery) , an industrial device and applications (e.g., a robot and/or other wireless devices operating in an industrial and/or an automated processing chain contexts) , a consumer electronics device, a device operating on commercial and/or industrial wireless networks, and the like. In the following description, the terms “terminal device” , “communication device” , “terminal” , “user equipment” and “UE” may be used interchangeably.

As used herein, the term “resource” , “transmission resource” , “resource block” , “physical resource block” (PRB) , “uplink (UL) resource” or “downlink (DL) resource” may refer to any resource for performing a communication, for example, a communication between a terminal device and a network device, such as a resource in time domain, a resource in frequency domain, a resource in space domain, a resource in code domain, a resource in a combination of more than one domain or any other resource enabling a communication, and the like. In the following, a resource in time domain (such as, a subframe) will be used as an example of a transmission resource for describing some example embodiments of the present disclosure. It is noted that example embodiments of the present disclosure are equally applicable to other resources in other domains.

As discussed above, SDT technologies have been proposed to reduce the signaling overhead and delay avoiding transiting to RRC connected mode and currently the NR system supports both RACH based SDT (i.e., RA-SDT) and CG based SDT (i.e. CG-SDT) . The term “SDT procedure” refers to the whole procedure for the RA-SDT or CG-SDT.

In the CG-SDT procedure, the terminal device may transmit the Common Control Channel (CCCH) message (or CCCH payload, or SDU (Service Data Unit) ) for the CG-SDT procedure by the CG resource in an initial phase of the CG-SDT procedure. For the RA-SDT procedure, the terminal device may first transmit the CCCH message with random access (RA) procedure in RA-SDT procedure, via message 3 (Msg3) of 4-step RA process or message A (MsgA) of 2-step RA process.

In Rel. 17, a timer, named T319a, has also been introduced for the SDT procedure. The timer T319a may indicate a maximum time that the terminal device can try or perform the SDT procedure, to enable failure recovery when no response from the network device to the terminal device or when network device loses the terminal device during the SDT procedure for some reason (e.g., beam outage) and to define the maximum time the SDT procedure can last.

To keep the synchronization for the Timer T319a between the terminal device and the network device, the agreement in Radio Access Network Work Group 2 (RAN2) specifies that the start position of the timer T319a is synchronized when the terminal device first transmits the CG-SDT or RA-SDT message with CCCH message included (i.e., the first SDT transmission with CCCH payload) . In other word, the terminal device will start the timer T319a upon the first transmission of CCCH message, and the network device will start a corresponding time upon receipt of the first transmission.

A potential problem with the above agreement in RAN2 lies in that the network device may not receive the terminal device’s first SDT transmission with CCCH message. In such a case, the terminal device already starts the timer and may re-transmit the CCCH message over CG in CG-SDT procedure or via Msg3/MsgA in RA-SDT procedure. However, the network device will not start the corresponding timer until receipt of the CCCH message. Therefore, as long as there is at least one re-transmission of the CCCH message, the terminal device and the network device would get unsynchronized about the timer operation.

To this end, according to embodiments of the present disclosure, there is provided a solution for keeping synchronization for the timer between the terminal device and the network device in the SDT procedure.

In embodiments of the present disclosure, it is proposed to restart the timer T319a at suitable position to enable the synchronization. Particularly, the timer T319a may be restarted when any of the following is met: transmission of message 3, Msg3, in a random access, RA, procedure, transmission of message A, MsgA, in a RA procedure, or receipt of a first response from a network device to a configured grant transmission for a configured grant -small data transmission, CG-SDT, procedure.

In the RA-SDT procedure, an RA procedure is used to initiate the STD procedure. In the 4-step RA procedure, message 1 (Msg1) including a preamble is transmitted to the network device to make a random access attempt; message 2 (Msg 2) containing an RAR to Msg1 is then transmitted from the network device to the terminal device; using the resources indicated in Msg 2, Msg 3 will be transmitted to the network device. If Msg 4, (a response to Msg 3) is not received from the network device, the terminal device may start another round of random access attempt and may send another Msg3 in this attempt. Such Msg 3 are new Msg 3. In addition, in case of unsuccessful transmission of new Msg3, i.e., the Msg3 is received but not received by the network device successfully, the terminal device may perform a Hybrid Automatic Repeat request, HARQ, re-transmissions for the Msg3. Such retransmitted Msg 3 can be referred to as HARQ retransmitted Msg3. Msg3 may include new Msg3 and retransmitted Msg3. The new Msg3 transmission refers to those scheduled by Random Access Response (RAR) in 4-step RA procedure or by a fallback RAR in 2-step RA procedure. In a two-step RA procedure, Message A (MsgA) including both a preamble and CCCH message is transmitted to the network device and if MsgA is not received, the MsgA can be retransmitted again; if the Msg A is received but CCCH message is not received successfully, a fallback RAR is transmitted to the terminal device and 4-step RAR will be performed, i.e., Msg 3 including a CCCH message will be further transmitted.

The CG-SDT procedure may have “initial CG-SDT transmission” and the “subsequent CG-SDT transmission” . The “initial CG-SDT transmission” refers to the initial phase in a CG-SDT procedure, which can also be called as a CG transmission. In the initial CG-SDT transmission, the terminal device transmits the Common Control Channel (CCCH) message (or CCCH payload) for the CG-SDT procedure by the CG resource. The terminal device may perform re-transmission of CCCH message in initial CG-SCG transmission if no response is received from the network device. Therefore, the initial CG-SCG transmission may comprise one or more transmissions of CCCH message, wherein, the first one of these transmissions may be referred to as “a first transmission” or a first CG transmission hereinafter. In a case wherein the network device receives the CCCH message but not receives the message successfully, the terminal device may also perform scheduled HARQ re-transmission by means of a dynamic grant in the initial CG-STD transmission. After the successful transmission of CCCH message, the terminal device may perform “subsequent CG-STD transmission, ” which refers to the subsequent STD phase after the initial phase in SDT procedure.

For the CG-SDT procedure, this first SDT transmission with CCCH message may refer to the first transmission in the initial CG-SDT transmission; for the RA-SDT transmission, it may refer to the first Msg3 or MsgA transmission in the RA procedure.

In some embodiments, for a RA-SDT procedure, after starting the timer T319a by the first SDT transmission including the CCCH message in the RA procedure of RA-SDT (first MsgA in 2-step or first Msg3 in 4-step RA procedures) , the UE may re-starts the running Timer T319a after each new Msg3 or MsgA transmission within the same RA procedure. The new Msg3 transmission may be scheduled by RAR (Random Access Response) in 4-step RA procedure, or alternatively scheduled by a fallback RAR in 2-step RA procedure. Or additionally, the timer T319a may be re-started after each HARQ re-transmission of Msg3 transmission (even though the network device knows the first occasion when the Msg3 is transmitted in this case) .

In some embodiments, for a CG-SDT procedure, after starting the timer T319a by the first SDT transmission including the CCCH message, the terminal device may keep the timer running for any terminal device initiated re-transmission of the initial CG-SDT transmission including the CCCH message when no response is received form the network device. And the terminal device may re-start the timer when a first response to the transmission including CCCH message is received from the network device. For example, the timer may restart from the CG occasion for which network device provided response to the terminal device. In such a case, the terminal device may re-start the timer in the previously transmitted CG occasion after the network device confirmed the receiving of the first CG-SDT transmission, or consider it restarted in the previously transmitted CG occasion after the network device confirmed the receiving of the first CG-SDT transmission, for example, by adjusting a proper starting value, a timer period of the timer. Additionally, the timer could also be re-started after each dynamic grant scheduled HARQ re-transmission of the first CG-SDT transmission (even though network device knows the first occasion when the CG is transmitted in this case) .

Although functionalities described herein can be performed, in various example embodiments, in a fixed and/or a wireless network node may, in other example embodiments, functionalities may be implemented in user equipment (such as a cell phone or tablet computer or laptop computer or desktop computer or mobile IOT device or fixed IOT device) . This user equipment may, for example, be furnished with corresponding capabilities as described in connection with the fixed and/or the wireless network node (s) , as appropriate. The user equipment may be the user equipment and/or or a control device, such as a chipset or processor, configured to control the user equipment when installed therein. Examples of such functionalities include the bootstrapping server function and/or the home subscriber server, which may be implemented in the user equipment apparatus by providing the user equipment apparatus with software configured to cause the user equipment apparatus to perform from the point of view of these functions/nodes.

Principle and embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. It is to be noted that these embodiments are given only for illustration purposes without suggesting any limitation to the present disclosure in any manner.

Reference is first made to Fig. 1, which illustrates an example communication system 100 in which embodiments of the present disclosure may be implemented. As illustrated, the system 100 includes a network device, such as a network device 111. The system 100 also includes terminal devices, such as a terminal device is 101. The terminal device 101 capable of connecting (for example, wirelessly) and communicating with the network devices 111 in both UL and DL, to perform, e.g., an SDT procedure. In communication systems, the UL refers to a communication link in a direction from a terminal device to a network device, and the DL refers to a communication link in a direction from the network device to the terminal device.

It is to be understood that the number of network devices and terminal devices is only for the purpose of illustration without suggesting any limitations. The system 100 may include any suitable number of network devices and terminal devices adapted for implementing embodiments of the present disclosure.

Communications in the communication system 100 may be implemented according to any proper communication protocol (s) , comprising, but not limited to, cellular communication protocols of the third generation (3G) , the fourth generation (4G) and the fifth generation (5G) or beyond, wireless local network communication protocols such as Institute for Electrical and Electronics Engineers (IEEE) 802.11 and the like, and/or any other protocols currently known or to be developed in the future. Moreover, the communication may utilize any proper wireless communication technology, comprising 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 Multiple (OFDM) , Discrete Fourier Transform spread OFDM (DFT-s-OFDM) and/or any other technologies currently known or to be developed in the future.

Reference is now made to Fig. 2, which shows a process 200 for small data transmission, particularly in an RA-SDT procedure, according to an embodiment of the present disclosure. For the purpose of discussion, the process 200 will be described with reference to Fig. 1. The process 200 may involve the terminal device 101 and the network device 111 as illustrated in Fig. 1. It would be appreciated that although the process 200 has been described in the communication system 100 of Fig. 1, this process may be likewise applied to other communication scenarios where SDT transmission is supported. It would also be appreciated that although the small data transmission of the terminal device 101 is discussed, a similar process can be applied for any other terminal devices.

In the process 200, the terminal device 101 initiates a RA-SDT procedure with 4-step RA procedure. The terminal device 101 transmits 201 message 1 (Msg1) including a RA preamble to the network device 111. The network device 111 transmits 202 message 2 (Msg2) as an RAR response to the terminal device 101. Upon reception of the Msg2, the terminal device 101 transmits 203 a Msg3 to the network device 111. In the RA-SDT procedure, the Msg3 has the CCCH message for the SDT procedure. Upon transmission of the Msg 3, , the terminal device 101 may start 204 the Timer T319a. Since no response to Msg3 is received from the network device 111 (e.g., the Msg3 is not received by the network device 111) , the terminal device 101 transmits 205 another Msg1 to the network device 111. The network device 111 transmits 206 another message 2 (Msg2) as an RAR response to the terminal device 101. Upon reception of the Msg2, the terminal device 101 transmits 207 another Msg3 to the network device 111 using the resource indicated in Msg 2. The new Msg3 also includes the CCCH message. Upon transmission of this Msg 3, the terminal device 101 may restart 208 the timer T319a.

If the network receives the Msg3 but does not decode successfully, the network device transmits 209 a HARQ message (e.g., NACK) to the terminal device 101 to indicate the terminal device that the Msg3 should be re-transmitted. Then the terminal device retransmits 210 the Msg3 to the network device 111 in a HARQ procedure.

In some embodiments, as an option, the terminal device may additionally, restart 211 the timer again. The network device 111 transmits 212 a message 4 (Msg4) upon the successful reception of the retransmitted Msg3.

In some embodiments, the terminal device 101 may alternatively not restart 205 the timer T319a for the above HARQ re-transmission of the Msg3 transmission; instead, it may only restart the timer upon transmission of each new Msg3.

Reference is further made to Fig. 3, which shows a process 300 for small data transmission, particularly in an RA-SDT procedure, according to an embodiment of the present disclosure. For the purpose of discussion, the process 300 will be described with reference to Fig. 1. The process 300 may involve the terminal device 101 and the network device 111 as illustrated in Fig. 1. It would be appreciated that although the process 300 has been described in the communication system 100 of Fig. 1, this process may be likewise applied to other communication scenarios. It would also be appreciated that although the small data transmission of the terminal device 101 is discussed, a similar process can be applied for any other terminal devices.

As illustrated in Fig. 3, in the process 300, the terminal device 101 initiates a RA-SDT procedure with 2-step RA procedure. The terminal device 101 transmits 301 MsgA to the network device 111. The MsgA has the CCCH message. And then the terminal device 101 starts 302 the T319a timer. Since no response from the network device 111 (e.g., the MsgA is not received by the network device 111) , the terminal device 101 transmits 303 another MsgA to the network device 111. Upon the transmission of this MsgA, the terminal device restarts 304 the timer. Upon reception of the MsgA, the network device 111 starts the corresponding timer and transmits 305 message B (MsgB) to the terminal device 101.

Reference is then made to Fig. 4, which shows a process 400 for small data transmission, particularly in an RA-SDT procedure, according to an embodiment of the present disclosure. For the purpose of discussion, the process 400 will be described with reference to Fig. 1. The process 400 may involve the terminal device 101 and the network device 111 as illustrated in Fig. 1. It would be appreciated that although the process 400 has been described in the communication system 100 of Fig. 1, this process may be likewise applied to other communication scenarios. It would also be appreciated that although the small data transmission of the terminal device 101 is discussed, a similar process can be applied for any other terminal devices.

In the process 400, the terminal device 101 initiates a RA-SDT procedure with 2-step RA procedure but falls back to a 4-step RA procedure. As illustrated in Fig. 4, the terminal device 101 transmits 401 a MsgA to the network device 111. The MsgA includes the CCCH message. Then the terminal device 101 starts 402 the Timer T319a. If the network device receives the MsgA but the CCCH message is not successfully received, the network device 111 transmits 403 a fallback RAR to the terminal device 101. Upon the reception of the fallback RAR, the terminal device 101 will fall back to a 4-step RA procedure. In such a case, the terminal device performing the RA procedure similar to those illustrated in Fig. 2. For example, the terminal device transmits 404 the Msg3 to the network device 111. The Msg3 has the CCCH message. Then the terminal device 101 may restart 405 the Timer T319a. Similarly, if the network device 111 does not receive the Msg3, the terminal device may transmit the Msg3 again and restart the timer T319a accordingly.

In addition, if the network device 111 does not successfully receive the Msg3, it transmits a HARQ message (NACK) to the terminal device 101. And then the terminal device 101 may retransmit the Msg3 in a HARQ process and restart 408 the timer T319a again. Upon the successful reception of the Msg3, the network device 111 transmits 409 a Msg4 to the terminal device 101.

Reference is further made to Fig. 5, which shows a process 500 for small data transmission, particularly in CG-SDT procedure, according to an embodiment of the present disclosure. For the purpose of discussion, the process 500 will be described with reference to Fig. 1. The process 500 may involve the terminal device 101 and the network device 111 as illustrated in Fig. 1. It would be appreciated that although the process 500 has been described in the communication system 100 of Fig. 1, this process may be likewise applied to other communication scenarios. It would also be appreciated that although the small data transmission of the terminal device 101 is discussed, a similar process can be applied for any other terminal devices.

In the process 500, the terminal device 101 initiates a CG-SDT procedure using CG resources. Particularly, the terminal device 101 transmits 501 a first transmission including CCCH message to the network device 111. Then the terminal device 101 starts 502 the Timer T319a. Since no response from the network device 111 (e.g., the first transmission is not received by the network device 111) , the terminal device 101 performs 503 another transmission of CCCH message in Msg3 to the network device 111. The transmission also has the CCCH message. Upon reception of the retransmission, the network device 111 may start the corresponding timer and transmit 504 a response to the terminal device 101, a first response of the CG transmission. Upon reception of the first response, and the terminal device 101 restarts 505 the timer. In such a case, the terminal device may re-start the timer in the previously transmitted CG occasion after the network device confirmed the receiving of the first CG-SDT transmission, or consider it restarted in the previously transmitted CG occasion after the network device confirmed the receiving of the first CG-SDT transmission, for example, by adjusting a proper starting value, a timer period of the timer. If there are more than one CCCH messages between the first CCCH message and the reception of the first response, there timer will not restart in response to these CCCH messages but keeps the timer running before receiving the first response.

Additionally, the terminal device may also restart 507 the timer T319a after each dynamic grant scheduled HARQ re-transmission 506 of the first CG-SDT transmission (even though NW knows the first occasion when the Msg3 is transmitted in this case) .

Fig. 6 shows a flowchart of an example method 600 implemented at a terminal device in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 600 will be described from the perspective of the terminal device 101 with reference to Fig. 1.

At block 610, the terminal device 101 may determine any one of the following conditions is met: transmission of message 3, Msg3, in a random access, RA, procedure, transmission of MsgA, in a RA procedure, or receipt of a first response from a network device to a configured grant transmission for a configured grant (CG) -SDT procedure.

At block 620, the terminal device 101 may restart a timer for a small data transmission, SDT, procedure while the timer is already running.

In some embodiments, the Msg3 may be scheduled by any one of: a random access response, RAR, in a 4-step RA procedure; a fallback RAR in a 2-step RA procedure; or a Hybrid Automatic Repeat request, HARQ, re-transmission of a Msg3 transmission.

In some embodiments, the Msg3 or MsgA may include CCCH, message.

In some embodiments, the method further may comprise starting the timer upon a first transmission including a CCCH message in the CG-SDT procedure.

In some embodiments, the method further may comprise keeping the timer running before receiving the first response from the network device.

In some embodiments, the timer may be restarted from a CG occasion for which the network device provided the first response to the terminal device.

In some embodiments, the restarting conditions may further comprise a dynamic grant scheduled HARQ re-transmission of the CG transmission.

In some embodiments, the RA procedure may be a part of random access SDT, RA-SDT, procedure.

In some embodiments, the timer may be stopped upon the reception of any one of: RRCResume message, RRCSetup message, RRCRelease message, RRCReject, or failure to resume RRC connection for SDT.

In some embodiments, the terminal device is further caused to, upon expiry of the timer, perform the actions of going to RRC_IDLE state.

In some embodiments, a terminal device may one or more processors; and one or more memories including computer program codes. The one or more memories and the computer program codes are configured to, with the one or more processors, cause the terminal device to performing any of the method 600 (for example, the terminal device 101) . For example, the terminal device may be caused to determine any one of the following conditions is met: transmission of message 3, Msg3, in a random access, RA, procedure, transmission of message A, MsgA, in a RA procedure, or receipt of a first response from a network device to a configured grant transmission for a configured grant -small data transmission, CG-SDT, procedure; and restart a timer for a small data transmission, SDT, procedure while the timer is already running.

In some embodiments, an apparatus capable of performing any of the method 600 (for example, the terminal device 101) may comprise means for performing the respective steps of the method 600. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

In some embodiments, the apparatus comprises means for means for determining any one of the following conditions is met: transmission of message 3, Msg3, in a random access, RA, procedure, transmission of message A, MsgA, in a RA procedure, or receipt of a first response from a network device to a configured grant transmission for a configured grant (CG) -SDT procedure; and means for restarting a timer for a small data transmission, SDT, procedure while the timer is already running.

In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of the method 600. In some embodiments, the means comprises at least one processor; and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

FIG. 7 is a simplified block diagram of a device 700 that is suitable for implementing embodiments of the present disclosure. The device 700 may be provided to implement the communication device, for example the terminal device 101, the network device 111 as shown in Fig. 1. As shown, the device 700 includes one or more processors 710, one or more memories 740 coupled to the processor 710, and one or more transmitters and/or receivers (TX/RX) 740 coupled to the processor 710.

The TX/RX 640 is for bidirectional communications. The TX/RX 740 has at least one antenna to facilitate communication. The communication interface may represent any interface that is necessary for communication with other network elements.

The processor 710 may be of any type suitable to the local technical network and may include one or more of the following: general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 700 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

The memory 720 may include one or more non-volatile memories and one or more volatile memories. Examples of the non-volatile memories include, but are not limited to, a Read Only Memory (ROM) 724, an electrically programmable read only memory (EPROM) , a flash memory, a hard disk, a compact disc (CD) , a digital video disk (DVD) , and other magnetic storage and/or optical storage. Examples of the volatile memories include, but are not limited to, a random access memory (RAM) 722 and other volatile memories that will not last in the power-down duration.

A computer program 730 includes computer executable instructions that are executed by the associated processor 710. The program 730 may be stored in the ROM 1020. The processor 710 may perform any suitable actions and processing by loading the program 730 into the RAM 722.

The embodiments of the present disclosure may be implemented by means of the program 730 so that the device 700 may perform any process of the disclosure as discussed with reference to FIGs. 2 to 6. The embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

In some embodiments, the program 730 may be tangibly contained in a computer readable medium which may be included in the device 700 (such as in the memory 720) or other storage devices that are accessible by the device 700. The device 700 may load the program 730 from the computer readable medium to the RAM 722 for execution. The computer readable medium may include any types of tangible non-volatile storage, such as ROM, EPROM, a flash memory, a hard disk, CD, DVD, and the like. Fig. 8 shows an example of the computer readable medium 800 in form of CD or DVD. The computer readable medium has the program 730 stored thereon.

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 which may be executed by a controller, microprocessor or other computing device. While various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representations, it is to be understood that the block, apparatus, system, technique or method described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, being executed in a device on a target real or virtual processor, to carry out the

processes

200, 300, 400 and 500, and method 600 as described above with reference to FIGs. 2 to 6. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

Program code for carrying out 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, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the processor or controller, cause the functions/operations specified in the flowcharts and/or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

In the context of the present disclosure, the computer program codes or related data may be carried by any suitable carrier to enable the device, apparatus or processor to perform various processes and operations as described above. Examples of the carrier include a signal, computer readable medium, and the like.

The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include but 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 would 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.

Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to 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 sub-combination.

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

Claims

A terminal device, comprising:

one or more transceivers; and

one or more processers communicatively coupled to the one or more transceivers, and configured to cause the terminal device to:

determine any one of the following conditions is met:

- transmission of message 3, Msg3, in a random access, RA, procedure,

- transmission of message A, MsgA, in a RA procedure, or

- receipt of a first response from a network device to a configured grant transmission for a configured grant -small data transmission, CG-SDT, procedure; and

restart a timer for a small data transmission, SDT, procedure while the timer is already running.
The terminal device of claim 1, wherein, the Msg3 is scheduled by any one of:

a random access response, RAR, in a 4-step RA procedure;

a fallback RAR in a 2-step RA procedure; or

a Hybrid Automatic Repeat request, HARQ, re-transmission of a Msg3 transmission.
The terminal device of claim 1 or 2, wherein the Msg3 or MsgA includes common control channel, CCCH, message.
The terminal device of claim 1, wherein the terminal device is further caused to:

start the timer upon a first transmission including a CCCH message in the CG-SDT procedure.
The terminal device of claim 4, wherein the terminal device is further caused to:

keep the timer running before receiving the first response from the network device.
The terminal device of claim 4 or 5, wherein the terminal device is caused to restart the timer for the CG-SDT procedure by:

re-starting the timer from a CG occasion for which the network device provided the first response to the terminal device.
The terminal device of any one of claims 1 to 5, wherein the restarting conditions further comprise:

a dynamic grant scheduled HARQ re-transmission of the configured grant transmission.
The terminal device of claim 1, wherein the RA procedure is a part of random access SDT, RA-SDT, procedure.
The terminal device of claim 1, wherein the timer is stopped upon the reception of any one of:

a Radio Resource Control, RRC, resume message,

an RRC setup message,

an RRC release message,

an RRC reject message, or

failure to resume RRC connection for SDT; and/or wherein the terminal device is further caused to, upon expiry of the timer, perform actions of going to RRC_IDLE.
A method at a terminal device comprising:

determining any one of the following conditions is met:

- transmission of message 3, Msg3, in a random access, RA, procedure,

- transmission of message A, MsgA, in a RA procedure, or

- receipt of a first response from a network device to a configured grant transmission for a configured grant -small data transmission, CG-SDT, procedure; and

restarting a timer for a small data transmission, SDT, procedure while the timer is already running.
The method of claim 10, wherein, the Msg3 is scheduled by any one of:

a random access response, RAR, in a 4-step RA procedure;

a fallback RAR in a 2-step RA procedure; or

a Hybrid Automatic Repeat request, HARQ, re-transmission of a Msg3 transmission.
The method of claim 10 or 11, wherein the Msg3 or the MsgA includes common control channel, CCCH, message.
The method of claim 10, further comprises:

starting the timer upon a first transmission including a CCCH message in the CG-SDT procedure.
The method of claim 13, further comprises:

keeping the timer running before receiving the first response from the network device.
The method of claim 13 or 14, further comprises:

re-starting the timer from a CG occasion for which the network device provided the first response to the terminal device.
The method of claim 10, wherein the restarting conditions further comprise:

a dynamic grant scheduled HARQ re-transmission of the configured grant transmission.
The method of claim 10, wherein the RA procedure is a part of random access SDT, RA-SDT, procedure.
The method of claim 10, wherein the timer is stopped upon the reception of any one of:

a Radio Resource Control, RRC, resume message,

an RRC setup message,

an RRC release message,

an RRC reject message, or

failure to resume RRC connection for SDT; and/or

wherein the terminal device is further caused to, upon expiry of the timer, perform the actions of going to RRC_IDLE.
A terminal device, comprising:

one or more processors; and

one or more memories including computer program codes;

wherein the one or more memories and the computer program codes are configured to, with the one or more processors, cause the terminal device to:

determine any one of the following conditions is met:

- transmission of message 3, Msg3, in a random access, RA, procedure,

- transmission of message A, MsgA, in a RA procedure, or

- receipt of a first response from a network device to a configured grant transmission for a configured grant -small data transmission, CG-SDT, procedure; and

restart a timer for a small data transmission, SDT, procedure while the timer is already running.
An apparatus of terminal device comprising:

means for determining any one of the following conditions is met:

transmission of message 3, Msg3, in a random access, RA, procedure,

transmission of message A, MsgA, in a RA procedure, or

receipt of a first response from a network device to a configured grant transmission for a configured grant -small data transmission, CG-SDT procedure; and

means for restarting a timer for a small data transmission, SDT, procedure while the timer is already running.
A non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the method of any of claims 10 to 18.