WO2023060413A1

WO2023060413A1 - Method, device and computer storage medium of communication

Info

Publication number: WO2023060413A1
Application number: PCT/CN2021/123164
Authority: WO
Inventors: Da Wang; Gang Wang
Original assignee: Nec Corporation
Priority date: 2021-10-12
Filing date: 2021-10-12
Publication date: 2023-04-20

Abstract

In accordance with a determination that a SDT procedure fails, a terminal device (110) stores information of the failed SDT procedure, and transmits, to a network device (120), a first indication indicating that the information is available. In this way, information of an unsuccessful SDT procedure may be stored and reported to the network and may facilitate the network to identify problems in the SDT procedure and optimize the SDT procedure.

Description

METHOD, DEVICE AND COMPUTER STORAGE MEDIUM OF COMMUNICATION

TECHNICAL FIELD

Embodiments of the present disclosure generally relate to the field of telecommunication, and in particular, to methods, devices and computer storage media of communication for small data transmission (SDT) .

BACKGROUND

In new radio (NR) technology, a self-organizing network (SON) , which encompasses solutions for network self-configuration and self-optimization, is introduced to support deployment of system and performance optimization. The following three features on SON are introduced: mobility robustness optimization (MRO) , mobility load balancing (MLB) and random access channel (RACH) optimization. Besides, other features enabling particular aspects of network self-optimization are also studied: minimization of drive tests (MDT) , energy saving (ES) , interference cancellation (IC) , time division duplex (TDD) uplink (UL) /downlink (DL) traffic adaptation (eIMTA) , collaborative multi-point operation (CoMP) , etc.

In the third generation partnership project (3GPP) Release 16 and Release 17, the feature of SON/MDT is supported, and more and more NR features will be considered in future for network self-optimization. One of possible objectives is to support enhancements for SDT so as to achieve enhancements for network self-optimization.

SUMMARY

In general, embodiments of the present disclosure provide methods, devices and computer storage media of communication for SDT.

In a first aspect, there is provided a method of communication. The method comprises: in accordance with a determination that a SDT procedure fails, storing, at a terminal device, information of the failed SDT procedure; and transmitting, to a network device, a first indication indicating that the information is available.

In a second aspect, there is provided a method of communication. The method comprises: receiving, at a network device and from a terminal device, a first indication indicating that information of a failed SDT procedure is available.

In a third aspect, there is provided a terminal device. The terminal device comprises a processor configured to perform the method according to the first aspect of the present disclosure.

In a fourth aspect, there is provided a network device. The network device comprises a processor configured to perform the method according to the second aspect of the present disclosure.

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

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

Other features of the present disclosure will become easily comprehensible through the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

Through the more detailed description of some embodiments of the present disclosure in the accompanying drawings, the above and other objects, features and advantages of the present disclosure will become more apparent, wherein:

FIG. 1A illustrates an example communication network in which some embodiments of the present disclosure can be implemented;

FIG. 1B illustrates a schematic diagram of a user plane (UP) protocol stack in which some embodiments of the present disclosure can be implemented;

FIG. 1C illustrates a schematic diagram of a control plane (CP) protocol stack in which some embodiments of the present disclosure can be implemented;

FIG. 2A illustrates a schematic diagram illustrating a SDT procedure for one-shot in which some embodiments of the present disclosure can be implemented;

FIG. 2B illustrates a schematic diagram illustrating a SDT procedure comprising initial transmission and subsequent transmission in which some embodiments of the present disclosure can be implemented;

FIG. 3 illustrates a schematic diagram illustrating a process for communication for a reporting of an unsuccessful SDT procedure according to embodiments of the present disclosure;

FIG. 4 illustrates an example method of communication implemented at a terminal device in accordance with some embodiments of the present disclosure;

FIG. 5 illustrates an example method of communication implemented at a network device in accordance with some embodiments of the present disclosure; and

FIG. 6 is a simplified block diagram of a device that is suitable for implementing 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 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 limitations 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.

As used herein, the term ‘terminal device’ refers to any device having wireless or wired communication capabilities. Examples of the terminal device include, but not limited to, user equipment (UE) , personal computers, desktops, mobile phones, cellular phones, smart phones, personal digital assistants (PDAs) , portable computers, tablets, wearable devices, internet of things (IoT) devices, Ultra-reliable and Low Latency Communications (URLLC) devices, Internet of Everything (IoE) devices, machine type communication (MTC) devices, device on vehicle for V2X communication where X means pedestrian, vehicle, or infrastructure/network, devices for Integrated Access and Backhaul (IAB) , Space borne vehicles or Air borne vehicles in Non-terrestrial networks (NTN) including Satellites and High Altitude Platforms (HAPs) encompassing Unmanned Aircraft Systems (UAS) , eXtended Reality (XR) devices including different types of realities such as Augmented Reality (AR) , Mixed Reality (MR) and Virtual Reality (VR) , the unmanned aerial vehicle (UAV) commonly known as a drone which is an aircraft without any human pilot, devices on high speed train (HST) , or image capture devices such as digital cameras, sensors, gaming devices, music storage and playback appliances, or Internet appliances enabling wireless or wired Internet access and browsing and the like. The ‘terminal device’ can further has ‘multicast/broadcast’ feature, to support public safety and mission critical, V2X applications, transparent IPv4/IPv6 multicast delivery, IPTV, smart TV, radio services, software delivery over wireless, group communications and IoT applications. It may also incorporated one or multiple Subscriber Identity Module (SIM) as known as Multi-SIM. The term “terminal device” can be used interchangeably with a UE, a mobile station, a subscriber station, a mobile terminal, a user terminal or a wireless device.

The term “network device” refers to a device which is capable of providing or hosting a cell or coverage where terminal devices can communicate. Examples of a network device include, but not limited to, a Node B (NodeB or NB) , an evolved NodeB (eNodeB or eNB) , a next generation NodeB (gNB) , a transmission reception point (TRP) , a remote radio unit (RRU) , a radio head (RH) , a remote radio head (RRH) , an IAB node, a low power node such as a femto node, a pico node, a reconfigurable intelligent surface (RIS) , and the like.

The terminal device or the network device may have Artificial intelligence (AI) or Machine learning capability. It generally includes a model which has been trained from numerous collected data for a specific function, and can be used to predict some information.

The terminal or the network device may work on several frequency ranges, e.g. FR1 (410 MHz to 7125 MHz) , FR2 (24.25GHz to 71GHz) , frequency band larger than 100GHz as well as Tera Hertz (THz) . It can further work on licensed/unlicensed/shared spectrum. The terminal device may have more than one connections with the network devices under Multi-Radio Dual Connectivity (MR-DC) application scenario. The terminal device or the network device can work on full duplex, flexible duplex and cross division duplex modes.

The embodiments of the present disclosure may be performed in test equipment, e.g. signal generator, signal analyzer, spectrum analyzer, network analyzer, test terminal device, test network device, channel emulator.

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

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. The term ‘includes’ and its variants are to be read as open terms that mean ‘includes, but is not limited to. ’ The term ‘based on’ is to be read as ‘at least in part based on. ’ The term ‘one embodiment’ and ‘an embodiment’ are to be read as ‘at least one embodiment. ’ The term ‘another embodiment’ is to be read as ‘at least one other embodiment. ’ The terms ‘first, ’ ‘second, ’ and the like may refer to different or same objects. Other definitions, explicit and implicit, may be included below.

In some examples, values, procedures, or apparatus are referred to as ‘best, ’ ‘lowest, ’ ‘highest, ’ ‘minimum, ’ ‘maximum, ’ or the like. It will be appreciated that such descriptions are intended to indicate that a selection among many used functional alternatives can be made, and such selections need not be better, smaller, higher, or otherwise preferable to other selections.

As known, SDT is a procedure allowing data transmission while remaining in an inactive state (i.e. without transitioning to a connected state) . SDT is enabled on a radio bearer basis and is initiated by a terminal device only if less than a configured amount of UL data awaits transmission across all radio bearers for which SDT is enabled and measured reference signal receive power (RSRP) in a cell is above a configured threshold.

Currently, there are various applications that involve exchange of small and infrequency data. For example, in some applications of mobile devices, SDT may involve traffic from Instant Messaging (IM) services, heart-beat or keep-alive traffic, for example, from IM or email clients and other services, push notifications in various applications, traffic from wearables (including, for example, periodic positioning information) , and/or the like. In some applications of non-mobile devices, SDT may involve sensor data (e.g., temperature, pressure readings transmitted periodically or in an event-triggered manner in an IoT network) , metering and alerting information sent from smart meters, and/or the like.

As mentioned above, one of possible objectives in future is to support enhancements for SDT so as to achieve enhancements for network self-optimization. In view of this, embodiments of the present disclosure provide a solution for reporting an unsuccessful SDT procedure to support enhancements for network self-optimization or other potential enhancements. Principles and implementations of the present disclosure will be described in detail below with reference to the figures.

EXAMPLE OF COMMUNICATION ENVIRONMENT

FIG. 1A illustrates a schematic diagram of an example communication network 100 in which some embodiments of the present disclosure can be implemented. As shown in FIG. 1A, the communication network 100 may include a terminal device 110 and a network device 120. The network device 120 provides a cell 121 to serve a terminal device. In the example of FIG. 1A, the terminal device 110 is located within the cell 121 of the network device 120, and the cell 121 may be referred to as a serving cell of the terminal device 110. The terminal device 110 may communicate with the network device 120. For example, the terminal device 110 may communicate with the network device 120 via one or more beams.

It is to be understood that the number of devices, cells and beams in FIG. 1A is given for the purpose of illustration without suggesting any limitations to the present disclosure. The communication network 100 may include any suitable number of network devices and/or terminal devices adapted for implementing implementations of the present disclosure. Further, the network device 120 may provide more cells for the terminal device 110.

As shown in FIG. 1A, the terminal device 110 may communicate with the network device 120 via a channel such as a wireless communication channel. The communications in the communication network 100 may conform to any suitable standards including, but not limited to, Global System for Mobile Communications (GSM) , Long Term Evolution (LTE) , LTE-Evolution, LTE-Advanced (LTE-A) , New Radio (NR) , Wideband Code Division Multiple Access (WCDMA) , Code Division Multiple Access (CDMA) , GSM EDGE Radio Access Network (GERAN) , Machine Type Communication (MTC) and the like. The embodiments of the present disclosure may be performed according to any generation communication protocols either currently known or to be developed in the future. Examples of the communication protocols include, but not limited to, the first generation (1G) , the second generation (2G) , 2.5G, 2.75G, the third generation (3G) , the fourth generation (4G) , 4.5G, the fifth generation (5G) communication protocols, 5.5G, 5G-Advanced networks, or the sixth generation (6G) networks.

Communication in a direction from the terminal device 110 towards the network device 120 is referred to as UL communication, while communication in a reverse direction from the network device 120 towards the terminal device 110 is referred to as DL communication. The terminal device 110 can move amongst the cells of the network device 120 and possibly other network devices. In UL communication, the terminal device 110 may transmit UL data and control information to the network device 120 via a UL channel. In DL communication, the network device 120 may transmit DL data and control information to the terminal device 110 via a DL channel.

The communications in the communication network 100 can be performed in accordance with UP and CP protocol stacks. Generally speaking, for a communication device (such as a terminal device or a network device) , there are a plurality of entities for a plurality of network protocol layers in a protocol stack, which can be configured to implement corresponding processing on data or signaling transmitted from the communication device and received by the communication device. FIG. 1B illustrates a schematic diagram 100B illustrating network protocol layer entities that may be established for UP protocol stack at devices according to some embodiments of the present disclosure.

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

FIG. 1C illustrates a schematic diagram 100C illustrating network protocol layer entities that may be established for CP protocol stack at devices according to some embodiments of the present disclosure. As shown in FIG. 1C, in the CP, each of the terminal device 110 and the network device 120 may comprise an entity for the L1 layer, i.e., an entity for a PHY layer (also referred to as a PHY entity) , and one or more entities for upper layers (L2 and L3 layers) including an entity for a MAC layer (also referred to as a MAC entity) , an entity for a RLC layer (also referred to as a RLC entity) , an entity for a PDCP layer (also referred to as a PDCP entity) , and an entity for a radio resource control (RRC) layer (also referred to as a RRC entity) . The RRC layer may be also referred to as an access stratum (AS) layer, and thus the RRC entity may be also referred to as an AS entity. As shown in FIG. 1C, the terminal device 110 may also comprise an entity for a non-access stratum (NAS) layer (also referred to as a NAS entity) . An NAS layer at the network side is not located in a network device and is located in a core network (CN, not shown) . In some cases, these entities are in a stack structure.

Generally, communication channels are classified into logical channels, transmission channels and physical channels. The physical channels are channels that the PHY layer actually transmits information. For example, the physical channels may comprise a physical uplink control channel (PUCCH) , a physical uplink shared channel (PUSCH) , a physical random-access channel (PRACH) , a physical downlink control channel (PDCCH) , a physical downlink shared channel (PDSCH) and a physical broadcast channel (PBCH) .

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

The logical channels are channels between the MAC layer and the RLC layer. For example, the logical channels may comprise a dedicated control channel (DCCH) , a common control channel (CCCH) , a paging control channel (PCCH) , broadcast control channel (BCCH) and dedicated traffic channel (DTCH) .

Generally, channels between the RRC layer and PDCP layer are called as radio bearers (RBs) . The terminal device 110 may be configured with at least one data radio bearer (DRB) for bearing data plane data and at least one signaling radio bearer (SRB) for bearing control plane data. In the context of the present disclosure, a DRB may be configured as supporting a transmission in an inactive state (i.e., supporting SDT) . Of course, a DRB may also be configured as not supporting a transmission in an inactive state. A SRB may be configured as supporting a transmission in an inactive state. Of course, a SRB may also be configured as not supporting a transmission in an inactive state.

In some scenarios, when the terminal device 110 in an inactive state has small and infrequency data traffic to be transmitted, the terminal device 110 may initiate a SDT procedure. FIG. 2A illustrates a schematic diagram illustrating a SDT procedure 200A for one-shot in which some embodiments of the present disclosure can be implemented. For the purpose of discussion, the process 200A will be described with reference to FIG. 1. The process 200A may involve the terminal device 110 and the network device 120 as illustrated in FIG. 1.

As shown in FIG. 2A, the terminal device 110 in an inactive state may transmit 211, to the network device 120, a RRC resume request message with UL data associated with the data traffic. For example, the terminal device 110 may transmit the RRC resume request message with UL data in Msg A of a 2-step RACH procedure or in Msg3 of a 4-step RACH procedure. Of course, the terminal device 110 may also transmit the RRC resume request message with UL data in a configured grant (CG) resource. Upon receipt of the RRC resume request and the UL data, the network device 120 may transmit 212 a RRC release message with DL data corresponding to the UL data to the terminal device 110. For example, the network device 120 may transmit the RRC release message with the DL data in Msg B of a 2-step RACH procedure or in Msg4 of a 4-step RACH procedure. Or the network device 120 may transmit the RRC release message with DL data as response of the transmission at the CG resource. So far, the SDT procedure 200A ends.

FIG. 2B illustrates a schematic diagram illustrating a SDT procedure 200B comprising initial transmission and subsequent transmission in which some embodiments of the present disclosure can be implemented. As shown in FIG. 2B, the terminal device 110 in an inactive state may transmit 221, to the network device 120, a RRC resume request message with UL data and a BSR. For example, the terminal device 110 may transmit the RRC resume request message with the UL data and the BSR in Msg A of a 2-step RACH procedure or in Msg 3 of a 4-step RACH procedure. Of course, the terminal device 110 may also transmit the RRC resume request message with UL data in a configured grant (CG) resource. The RRC resume request message may comprise a resume cause. Upon receipt of the RRC resume request message with the UL data and the BSR, the network device 120 may transmit 222 a response of the initial transmission to the terminal device 110. For example, the network device 120 may transmit an explicit RRC message as the response. As another example, the network device 120 may transmit an UL grant for further transmission. As another example, the network device 120 may transmit contention resolution information. In some embodiments, the network device 120 may also transmit DL data in the response to the terminal device 110. So far, the initial transmission is done.

Based on the response, the terminal device 110 may transmit 223 further UL data and BSR to the network device 120, for example, based on a dynamic grant or configured grant. Then the network device 120 may transmit 224 an UL grant for dynamic grant to the terminal device 110. In some embodiments, the network device 120 may transmit DL data with the UL grant to the terminal device 110. Based on the UL grant from the network device 120, the terminal device 110 may transmit 225 remaining UL data to the network device 120. Or the terminal device 110 may transmit 225 remaining UL data to the network device 120 using configured grant. Accordingly, the network device 120 may transmit 226 RRC release message to the terminal device 110. So far, subsequent transmission is done. That is, the SDT procedure 200B ends. It is to be understood that the SDT procedure 200B may comprise more or less steps in the subsequent transmission.

It is to be understood that a SDT procedure either takes place on RACH or type 1 CG resources. In the context of the present application, a SDT using a RACH resource may be referred to as a random access (RA) -based SDT procedure or a RA-SDT, and a SDT using a CG resource may be referred to as a CG-based SDT procedure or a CG-SDT. For a CG-based SDT procedure, resources for SDT may be configured either on initial bandwidth part (BWP) or on a dedicated BWP. For a RA-based SDT procedure, the network side may also configure whether 2-step and/or 4-step RA types may be used. For a CG-based SDT procedure, the first UL data (i.e., the starting UL data) may be transmitted in a CG resource. For a RA-based SDT procedure, the first UL data (i.e., the starting UL data) may be transmitted in Msg 3 or Msg A.

In some embodiments, once initiated, a SDT procedure lasts as long as a terminal device is not explicitly directed to an idle state (RRC_IDLE) or an inactive state (RRC_INACTIVE) , for example, via a RRCRelease message or to a connected state (RRC_CONNECTED) , for example, via a RRCResume message.

In some embodiments, after the initial SDT transmission, subsequent transmissions may be handled differently depending on the type of resources configured. For example, in case of using CG resources, the network side may schedule subsequent UL transmission using a dynamic grant or the subsequent UL transmission may take place on the next CG resource occasion. In case of using RACH resources, the network side may schedule subsequent UL and DL transmissions using dynamic grants and assignments, respectively, after the completion of the RA procedure.

In some embodiments for a CG-based SDT procedure, multiple CG resources may be configured for SDT. The CG resources may be associated with synchronization signal blocks (SSBs) . A synchronization signal (SS) -RSRP threshold may be configured for SSB selection. In some embodiments, the terminal device 110 may select one of the SSB with SS-RSRP above the SS-RSRP threshold and select a CG resource associated with the selected SS-RSRP for UL data transmission.

EXAMPLE IMPLEMENTATION OF REPORTING AN UNSUCCESSFUL SDT PROCEDURE

Embodiments of the present disclosure provide a solution of communication for reporting an unsuccessful SDT procedure. The detailed description will be given below in connection with FIG. 3.

FIG. 3 illustrates a schematic diagram illustrating a process 300 for communication for a reporting of an unsuccessful SDT procedure according to embodiments 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 110 and the network device 120 as illustrated in FIG. 1. Assuming that the terminal device 110 performs a SDT procedure, for example, as shown in FIGs. 2A and 2B.

As shown in FIG. 3, the terminal device 110 determines 310 whether the SDT procedure fails. The terminal device 110 may determine with the SDT procedure fails in any suitable ways, and the present disclosure does not limit this aspect.

If the SDT procedure fails, the terminal device 110 stores or logs 320 information of the failed SDT procedure. In some embodiments, the terminal device 110 may store the information of the failed SDT procedure if the SDT procedure is a RA-based SDT procedure.

In some embodiments where the SDT procedure is a RA-based SDT procedure, the terminal device 110 may store the information of the failed SDT procedure if a timer (for convenience, also referred to as a first timer herein) configured for detecting the failure of the SDT procedure expires. In some embodiments, the first timer may start upon transmission of a RRC resume request message for SDT and stop upon receipt of a RRC release or RRC resume or RRC reject message. In some embodiments, the first timer may start or restart after each UL transmission during SDT procedure. Of course, the first timer may be set in any other suitable manners.

In some embodiments where the SDT procedure is a RA-based SDT procedure, the terminal device 110 may store the information of the failed SDT procedure if a lower layer of the terminal device 110 indicates the failure of the SDT procedure to a RRC layer of the terminal device 110. For example, if a MAC layer of the terminal device 110 indicates the failure of a random access procedure for the SDT procedure to the RRC layer of the terminal device 110, the terminal device 110 may store the information of the failed SDT procedure. As another example, if the MAC layer of the terminal device 110 indicates a beam failure associated with the SDT procedure to the RRC layer of the terminal device 110, the terminal device 110 may store the information of the failed SDT procedure. As still another example, if a RLC layer of the terminal device 110 indicates to the RRC layer of the terminal device 110 that the number of retransmissions during the SDT procedure reaches a threshold number, the terminal device 110 may store the information of the failed SDT procedure. For example, if the RLC layer indicates that the maximum number of retransmissions is reached, the terminal device 110 may store the information of the failed SDT procedure.

It is to be understood that the terminal device 110 may store the information of the failed RA-based SDT procedure in response to any combination of the above or other conditions.

In some embodiments where the SDT procedure is a RA-based SDT procedure, the information of the failed SDT procedure may comprise information (for convenience, also referred to as first information herein) stored for a connection establishment failure (CEF) report, e.g., existing or future information stored for failed RRC resume procedure. In some embodiments, the first information may comprise at least one of the following:

a time stamp which is a period of time elapsed between the storing of the information and a reporting of the information;

a global cell identity of a serving cell when the SDT procedure fails, i.e., a cell which the terminal device attempted to access;

the latest available radio measurements for an frequency or RAT;

the latest detailed location information if available;

an index of a SSB of a downlink beam of a serving cell;

the latest number of consecutive connection failures in the last failed cell the terminal device has experienced independent of RRC state transitions;

RACH information, for example, tried SSB index and number of Random Access Preambles transmitted for each tried SSB in chronological order of attempts, contention detected as per RACH attempt, an indication whether the selected SSB is above or below the rsrp-ThresholdSSB threshold, as per RACH attempt;

a timing advance command (TAC) of a cell in which the terminal device performs a RA procedure;

the latest wireless local area network (WLAN) measurement results if available;

the latest Bluetooth measurement results if available; or

the latest sensor information if available.

In some additional or alternative embodiments, the information of the failed SDT procedure may comprise at least one of the following:

an indication (for convenience, also referred to as a second indication herein) indicating that the information is for the SDT procedure;

a data volume of uplink data to be transmitted when the SDT procedure is triggered;

a measured value of RSRP of a serving cell when the SDT procedure is triggered;

information (for convenience, also referred to as second information herein) regarding phases of the SDT procedure when the failure of the SDT procedure occurs, for example, an indication (for convenience, also referred to as a third indication herein) indicating whether the failure of the SDT procedure occurs before contention resolution or after successful contention resolution, or an indication (for convenience, also referred to as a fourth indication herein) indicating whether the failure of the SDT procedure occurs during a subsequent transmission phase or an initial transmission phase for the SDT procedure;

a cause of the failure of the SDT procedure, for example, an expiration of the first timer configured for detecting the failure of the SDT procedure, a random access problem, the number of retransmissions reaching a threshold number, or a beam failure associated with the SDT procedure;

an identity (ID) of a RB associated with uplink data triggering the SDT procedure, and data volume of the RB; or

information (for convenience, also referred to as third information herein) of a BWP selected for the SDT procedure, for example, BWP ID or any other suitable information.

The data volume or RSRP information may be used for the network device 120 to adjust a configuration of the data volume or RSRP threshold for SDT. The ID of RB may be used to adjust a configuration of which RB supporting SDT. The information regarding the phases of the SDT procedure and the cause of the failure of the SDT procedure may help the network device 120 to identify the reason of the failure. It is to be understood that any other suitable information is also feasible, and the present disclosure is not limited to the above-listed information.

In some embodiments where the SDT procedure is a RA-based SDT procedure, the terminal device 110 may store the information in a variable of the terminal device 110 for a CEF report. For example, the information of the failed RA-based SDT may be stored in the same UE variable for CEF information, e.g., VarConnEstFailReport. In some additional or alternative embodiments, the terminal device 110 may store the information in a dedicated variable of the terminal device 110. For example, the information of the failed RA-based SDT may be stored in a newly defined UE variable.

In some embodiments, the terminal device 110 may store the information of the failed SDT procedure if the SDT procedure is a CG-based SDT procedure. In some embodiments where the SDT procedure is a CG-based SDT procedure, the terminal device 110 may store the information of the failed SDT procedure if the first timer configured for detecting the failure of the SDT procedure expires.

In some embodiments where the SDT procedure is a CG-based SDT procedure, the terminal device 110 may store the information of the failed SDT procedure if a lower layer of the terminal device 110 indicates the failure of the SDT procedure to a RRC layer of the terminal device 110. For example, if the MAC layer of the terminal device 110 indicates the failure of a random access procedure for the SDT procedure to the RRC layer of the terminal device 110, the terminal device 110 may store the information of the failed SDT procedure. As another example, if the MAC layer of the terminal device 110 indicates a beam failure associated with the SDT procedure to the RRC layer of the terminal device 110, the terminal device 110 may store the information of the failed SDT procedure.

As still another example, if the RLC layer of the terminal device 110 indicates to the RRC layer of the terminal device 110 that the number of retransmissions during the SDT procedure reaches a threshold number, the terminal device 110 may store the information of the failed SDT procedure. For example, if the RLC layer indicates that the maximum number of retransmissions is reached, the terminal device 110 may store the information of the failed SDT procedure.

As yet another example, if the MAC layer of the terminal device 110 indicates to the RRC layer of the terminal device 110 that a timer (for convenience, also referred to as a second timer herein) configured for downlink control channel (for example, PDCCH) monitoring after a CG transmission for the SDT procedure expires, the terminal device 110 may store the information of the failed SDT procedure. For example, the second timer may be used to monitor a PDCCH transmission, which is addressed to a cell-radio network temporary identifier (C-RNTI) or configured scheduling-radio network temporary identifier (CS-RNTI) , when the second timer is running or within a time window for the PDCCH monitoring.

It is to be understood that the terminal device 110 may store the information of the failed the CG-based SDT procedure in response to any combination of the above or other conditions.

In some embodiments where the SDT procedure is a CG-based SDT procedure, the information of the failed SDT procedure may comprise information (for convenience, also referred to as fourth information herein) stored for a connection establishment failure (CEF) report, e.g., existing or future information stored for failed RRC resume procedure. In some embodiments, the fourth information may comprise at least one of the following:

a global cell identity of a serving cell when the SDT procedure fails;

the latest available radio measurements for an frequency or RAT;

the latest detailed location information if available;

the latest WLAN measurement results if available;

the latest Bluetooth measurement results if available; or

the latest sensor information if available.

information (for convenience, also referred to as fifth information herein) of a CG resource selected for a failed CG transmission of the SDT procedure, for example, an index of the failed CG resource;

an index of a SSB selected for the SDT procedure;

a measured value of RSRP of the selected SSB when a CG resource is selected;

data volume of uplink data to be transmitted when the SDT procedure is triggered;

a measured value of RSRP of a serving cell when the SDT procedure is triggered;

information (for convenience, also referred to as sixth information herein) regarding phases of the SDT procedure when the failure of the SDT procedure occurs, for example, an indication (for convenience, also referred to as a fifth indication herein) indicating whether the failure of the SDT procedure occurs during a subsequent transmission phase or an initial transmission phase for the SDT procedure;

a cause of the failure of the SDT procedure, for example, an expiration of a timer configured for detecting the failure of the SDT procedure, a random access problem, the number of retransmissions reaching a threshold number, or a beam failure associated with the SDT procedure;

an ID of a RB associated with uplink data triggering the SDT procedure, and data volume of the RB;

a value of a time alignment timer (TAT) for the SDT procedure when the SDT procedure is triggered, the TAT controlling how long the MAC entity considers that a timing advance value is valid for CG-based SDT; or

information (for convenience, also referred to as seventh information herein) of a BWP selected for the SDT procedure, for example, BWP ID or any other suitable information.

The information of the CG resource may help the network device 120 to optimize a CG configuration for SDT. The index of the SSB selected for the failed CG-based SDT procedure may also help the network device 120 to optimize a CG configuration for SDT. The measured value of RSRP of the selected SSB when a CG resource is selected may help the network device 120 to adjust a SSB threshold for CG resource selection. The value of TAT may help the network device 120 to adjust the maximum TAT volume for CG-based SDT. It is to be understood that any other suitable information is also feasible, and the present disclosure is not limited to the above-listed information.

In some embodiments where the SDT procedure is a CG-based SDT procedure, the terminal device 110 may store the information in a variable of the terminal device 110 for a CEF report. For example, the information of the failed CG-based SDT may be stored in the same UE variable for CEF information, e.g., VarConnEstFailReport. In this case, the perRAInfoList information may be set to a predefined value. In some additional or alternative embodiments, the terminal device 110 may store the information in a dedicated variable of the terminal device 110. For example, the information of the failed CG-based SDT may be stored in a newly defined UE variable.

So far, the storing of the information of the failed SDT procedure is described. Continue to refer to FIG. 3, the terminal device 110 transmits 330, to the network device 120, an indication (for convenience, also referred to as a first indication herein) indicating that the information is available. For example, the terminal device 110 may transmit the first indication to the network device 120 in a RRCReconfigurationComplete, RRCSetupComplete, RRCResumeComplete, or RRCRestablishmentComplete message. Of course, the terminal device 110 may transmit the first indication in any other suitable ways.

In some embodiments where the SDT procedure is a RA-based SDT procedure, the terminal device 110 may transmit the first indication to the network device 120 in an information element (IE) for a CEF report, e.g., connEstFailInfoAvailable or connEstFailReport. In some embodiments where the SDT procedure is a CG-based SDT procedure, the terminal device 110 may also transmit the first indication to the network device 120 in an IE for a CEF report, e.g., connEstFailInfoAvailable or connEstFailReport.

In some embodiments, the terminal device 110 may transmit the first indication to the network device 120 in a dedicated IE, for example a newly defined IE. In some embodiments, the terminal device 110 may transmit the first indication to the network device 120 in an IE common for a RA-based SDT procedure and a CG-based SDT procedure. Of course, the terminal device 110 may also transmit the first indication to the network device 120 in different IEs for a RA-based SDT procedure and a CG-based SDT procedure.

Upon receipt of the first indication, the network device 120 may transmit 340 a request for obtaining the information of the failed SDT procedure. For example, the network device 120 may request for the information of the failed SDT procedure from the terminal device 110 by a UEInformationRequest message. The network device 120 may request for the information of the failed SDT procedure using the same IE for CEF report, i.e. connEstFailReportReq-r16. The network device 120 may also request for the information of the failed SDT procedure using dedicated IE, i.e. newly defined IE for SDT, or newly defined IE for RA-SDT or CG-SDT. Of course, any other suitable ways are also feasible.

Upon receipt of the request, the terminal device 110 may transmit 350 the information of the failed SDT procedure to the network device 120. For example, the terminal device 110 may report the information of the failed SDT procedure to the network device 120 by a UEInformationResponse message. The terminal device 110 may report the information of the failed SDT procedure using the same IE for CEF report, i.e. connEstFailReport-r16. The terminal device 110 may report the information of the failed SDT procedure using a dedicated IE, i.e. newly defined IE for SDT, or newly defined IE for RA-SDT or CG-SDT. Of course, any other suitable ways are also feasible.

In some embodiments, the terminal device 110 may discard 360 the stored information of the failed SDT procedure after the information is successfully transmitted to the network device 120. In some embodiments, the terminal device 110 may determine whether a predetermined period of time elapses after the information is added into a variable of the terminal device 110. If the predetermined period of time elapses after the information is added into the variable of the terminal device 110, the terminal device 110 may discard 360’ the stored information of the failed SDT procedure. For example, the predetermined period of time may be 48 hours. Of course, any other suitable values are also feasible.

With the process of FIG. 3, the information of unsuccessful SDT procedure may be logged and reported to the network, and thus it is helpful for the network to identify the problems in the SDT procedure and optimize the SDT procedure.

EXAMPLE IMPLEMENTATION OF METHODS

Accordingly, embodiments of the present disclosure provide methods of communication implemented at a terminal device and a network device. These methods will be described below with reference to FIGs. 4 to 5.

FIG. 4 illustrates an example method 400 of communication implemented at a terminal device in accordance with some embodiments of the present disclosure. For example, the method 400 may be performed at the terminal device 110 as shown in FIG. 1. For the purpose of discussion, in the following, the method 400 will be described with reference to FIG. 1. It is to be understood that the method 400 may include additional blocks not shown and/or may omit some blocks as shown, and the scope of the present disclosure is not limited in this regard.

At block 410, the terminal device 110 determines whether a SDT procedure fails. If the SDT procedure fails, the process 400 proceeds to block 420.

At block 420, the terminal device 110 stores information of the failed SDT procedure. In some embodiments, the terminal device 110 may store the information in response to at least one of the following: the SDT procedure being a RA-based SDT procedure; an expiration of a first timer configured for detecting the failure of the SDT procedure; or a lower layer of the terminal device 110 indicating the failure of the SDT procedure to a RRC layer of the terminal device 110.

In some embodiments where the lower layer indicates the failure of the SDT procedure to the RRC layer, the terminal device 110 may store the information in response to at least one of the following: a MAC layer of the terminal device indicating the failure of a random access procedure for the SDT procedure; the MAC layer indicating a beam failure associated with the SDT procedure; or a RLC layer of the terminal device indicating that the number of retransmissions during the SDT procedure reaches a threshold number.

In some embodiments where the SDT procedure is a RA-based SDT procedure, the information may comprise at least one of the following: first information stored for a connection establishment failure report, a second indication indicating that the information is for the SDT procedure, a data volume of uplink data to be transmitted when the SDT procedure is triggered, a measured value of reference signal receive power of a serving cell when the SDT procedure is triggered, second information regarding phases of the SDT procedure when the failure of the SDT procedure occurs, a cause of the failure of the SDT procedure, an identity of a radio bearer associated with uplink data triggering the SDT procedure and data volume of the radio bearer, or third information of a bandwidth part selected for the SDT procedure.

In some embodiments, the first information may comprise at least one of the following: a time stamp which is a period of time elapsed between the storing of the information and the transmission of the first indication, a global cell identity of a serving cell when the SDT procedure fails, the latest available radio measurements for an frequency or RAT, the latest detailed location information if available, an index of a SSB of a downlink beam of a serving cell, the latest number of consecutive connection failures in the last failed cell the terminal device has experienced independent of RRC state transitions, RACH information, a TAC of a cell in which the terminal device performs a RA procedure, the latest WLAN measurement results if available, the latest Bluetooth measurement results if available, or the latest sensor information if available.

In some embodiments, the second information may comprise at least one of the following: a third indication indicating whether the failure of the SDT procedure occurs before contention resolution or after successful contention resolution, or a fourth indication indicating whether the failure of the SDT procedure occurs during a subsequent transmission phase or an initial transmission phase for the SDT procedure.

In some embodiments, the cause of the failure of the SDT procedure may comprise at least one of the following: an expiration of a first timer configured for detecting the failure of the SDT procedure, a random access problem, the number of retransmissions reaching a threshold number, or a beam failure associated with the SDT procedure.

In some embodiments, the terminal device 110 may store the information in response to at least one of the following: the SDT procedure being a CG-based SDT procedure; an expiration of a first timer configured for detecting the failure of the SDT procedure; or a lower layer of the terminal device 110 indicating the failure of the SDT procedure to a RRC layer of the terminal device 110.

In some embodiments where the lower layer indicates the failure of the SDT procedure to the RRC layer, the terminal device 110 may store the information in response to at least one of the following: a MAC layer of the terminal device indicating the failure of a random access procedure for the SDT procedure; the MAC layer indicating a beam failure associated with the SDT procedure; a RLC layer of the terminal device indicating that the number of retransmissions during the SDT procedure reaches a threshold number; or the MAC layer indicating an expiration of a second timer configured for downlink control channel monitoring after a CG transmission for the SDT procedure.

In some embodiments where the SDT procedure is a CG-based SDT procedure, the information may comprise at least one of the following: fourth information stored for a connection establishment failure report, fifth information of a CG resource selected for a failed CG transmission of the SDT procedure, an index of a SSB selected for the SDT procedure, a measured value of reference signal receive power of the selected SSB when a CG resource is selected, data volume of uplink data to be transmitted when the SDT procedure is triggered, a measured value of reference signal receive power of a serving cell when the SDT procedure is triggered, sixth information regarding phases of the SDT procedure when the failure of the SDT procedure occurs, a cause of the failure of the SDT procedure, an identity of a radio bearer associated with uplink data triggering the SDT procedure and data volume of the radio bearer, a value of a time alignment timer for the SDT procedure when the SDT procedure is triggered, or seventh information of a bandwidth part selected for the SDT procedure.

In some embodiments, the fourth information may comprise at least one of the following: a time stamp which is a period of time elapsed between the storing of the information and the transmission of the first indication, a global cell identity of a serving cell when the SDT procedure fails, the latest available radio measurements for an frequency or RAT, the latest detailed location information if available, the latest WLAN measurement results if available, the latest Bluetooth measurement results if available, or the latest sensor information if available.

In some embodiments, the sixth information may comprise at least one of the following: a fifth indication indicating whether the failure of the SDT procedure occurs during a subsequent transmission phase or an initial transmission phase for the SDT procedure.

In some embodiments, the terminal device 110 may store the information in a variable of the terminal device for a CEF report. In some alternative embodiments, the terminal device 110 may store the information in a dedicated variable of the terminal device 110.

At block 430, the terminal device 110 transmits, to the network device 120, a first indication indicating that the information is available.

In some embodiments, the terminal device 110 may transmit the first indication to the network device 120 in an IE for a CEF report. In some alternative embodiments, the terminal device 110 may transmit the first indication to the network device 120 in a dedicated IE.

In some embodiments, the terminal device 110 may receive, from the network device 120, a request for obtaining the information, and transmit the information to the network device 120. In some embodiments, the terminal device 110 may discard the stored information after the information is successfully transmitted to the network device 120. In some embodiments, the terminal device 110 may discard the stored information if a predetermined period of time elapses after the information is added into a variable of the terminal device 110.

With the method of FIG. 4, the information of unsuccessful SDT procedure may be stored and reported to the network side.

FIG. 5 illustrates an example method 500 of communication implemented at a network device in accordance with some embodiments of the present disclosure. For example, the method 500 may be performed at the network device 120 as shown in FIG. 1. For the purpose of discussion, in the following, the method 500 will be described with reference to FIG. 1. It is to be understood that the method 500 may include additional blocks not shown and/or may omit some blocks as shown, and the scope of the present disclosure is not limited in this regard.

At block 510, the network device 120 receives, from the terminal device 110, a first indication indicating that information of a failed SDT procedure is available. In some embodiments, the network device 120 may transmit, to the terminal device 110, a request for obtaining the information, and receive the information from the terminal device 110.

In some embodiments, the first information may comprise at least one of the following: a time stamp which is a period of time elapsed between the storing of the information and the transmission of the first indication, a global cell identity of a serving cell when the SDT procedure fails, the latest available radio measurements for an frequency or RAT, the latest detailed location information if available, an index of a SSB of a downlink beam of a serving cell, the latest number of consecutive connection failures in the last failed cell the terminal device 110 has experienced independent of RRC state transitions, RACH information, a TAC of a cell in which the terminal device 110 performs a RA procedure, the latest WLAN measurement results if available, the latest Bluetooth measurement results if available, or the latest sensor information if available.

In some embodiments, the cause of the failure of the SDT procedure may comprise at least one of the following: an expiration of a timer configured for detecting the failure of the SDT procedure, a random access problem, the number of retransmissions reaching a threshold number, or a beam failure associated with the SDT procedure.

In some embodiments where the SDT procedure is a CG-based SDT procedure, the information may comprise at least one of the following: fourth information stored for a CEF report, fifth information of a CG resource selected for a failed CG transmission of the SDT procedure, an index of a SSB selected for the SDT procedure, a measured value of reference signal receive power of the selected SSB when a CG resource is selected, data volume of uplink data to be transmitted when the SDT procedure is triggered, a measured value of reference signal receive power of a serving cell when the SDT procedure is triggered, sixth information regarding phases of the SDT procedure when the failure of the SDT procedure occurs, a cause of the failure of the SDT procedure, an identity of a radio bearer associated with uplink data triggering the SDT procedure and data volume of the radio bearer, a value of a time alignment timer for the SDT procedure when the SDT procedure is triggered, or seventh information of a bandwidth part selected for the SDT procedure.

In some embodiments, the network device 120 may receive the first indication from the terminal device 110 in an IE for a CEF report. In some embodiments, the network device 120 may receive the first indication from the terminal device 110 in a dedicated IE.

With the method of FIG. 5, the network side may receive the information of the unsuccessful SDT procedure. With the information, the network side may identify the problem of the SDT procedure and optimize the SDT procedure.

The implementations of the methods described in FIGs. 4-5 substantially correspond to that described with reference to FIG. 3, and thus other details are not repeated here.

EXAMPLE IMPLEMENTATION OF DEVICE

FIG. 6 is a simplified block diagram of a device 600 that is suitable for implementing embodiments of the present disclosure. The device 600 can be considered as a further example implementation of the terminal device 110 or the network device 120 as shown in FIG. 1. Accordingly, the device 600 can be implemented at or as at least a part of the terminal device 110 or the network device 120.

As shown, the device 600 includes a processor 610, a memory 620 coupled to the processor 610, a suitable transmitter (TX) and receiver (RX) 640 coupled to the processor 610, and a communication interface coupled to the TX/RX 640. The memory 610 stores at least a part of a program 630. The TX/RX 640 is for bidirectional communications. The TX/RX 640 has at least one antenna to facilitate communication, though in practice an Access Node mentioned in this application may have several ones. The communication interface may represent any interface that is necessary for communication with other network elements, such as X2/Xn interface for bidirectional communications between eNBs/gNBs, S1/NG interface for communication between a Mobility Management Entity (MME) /Access and Mobility Management Function (AMF) /SGW/UPF and the eNB/gNB, Un interface for communication between the eNB/gNB and a relay node (RN) , or Uu interface for communication between the eNB/gNB and a terminal device.

The program 630 is assumed to include program instructions that, when executed by the associated processor 610, enable the device 600 to operate in accordance with the embodiments of the present disclosure, as discussed herein with reference to FIGs. 1 to 5. The embodiments herein may be implemented by computer software executable by the processor 610 of the device 600, or by hardware, or by a combination of software and hardware. The processor 610 may be configured to implement various embodiments of the present disclosure. Furthermore, a combination of the processor 610 and memory 620 may form processing means 650 adapted to implement various embodiments of the present disclosure.

The memory 620 may be of any type suitable to the local technical network and may be implemented using any suitable data storage technology, such as a non-transitory computer readable storage medium, semiconductor based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory, as non-limiting examples. While only one memory 620 is shown in the device 600, there may be several physically distinct memory modules in the device 600. The processor 610 may be of any type suitable to the local technical network, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 600 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.

In some embodiments, a terminal device comprises a circuitry configured to: in accordance with a determination that a SDT procedure fails, store information of the failed SDT procedure; and transmit, to a network device, a first indication indicating that the information is available.

In some embodiments, the circuitry may be further configured to: receive, from the network device, a request for obtaining the information; and transmit the information to the network device.

In some embodiments, the circuitry may be further configured to: discard the stored information after the information is successfully transmitted to the network device; or discard the stored information if a predetermined period of time elapses after the information is added into a variable of the terminal device.

In some embodiments, the circuitry may be configured to store the information comprises storing the information in response to at least one of the following: the SDT procedure being a RA-based SDT procedure; an expiration of a first timer configured for detecting the failure of the SDT procedure; or a lower layer of the terminal device indicating the failure of the SDT procedure to a RRC layer of the terminal device. In some embodiments where the lower layer indicates the failure of the SDT procedure to the RRC layer, the circuitry may be configured to store the information in response to at least one of the following: a MAC layer of the terminal device indicating the failure of a random access procedure for the SDT procedure; the MAC layer indicating a beam failure associated with the SDT procedure; or a RLC layer of the terminal device indicating that the number of retransmissions during the SDT procedure reaches a threshold number.

In these embodiments, the information may comprise at least one of the following: first information stored for a connection establishment failure report, a second indication indicating that the information is for the SDT procedure, a data volume of uplink data to be transmitted when the SDT procedure is triggered, a measured value of reference signal receive power of a serving cell when the SDT procedure is triggered, second information regarding phases of the SDT procedure when the failure of the SDT procedure occurs, a cause of the failure of the SDT procedure, an identity of a radio bearer associated with uplink data triggering the SDT procedure and data volume of the radio bearer, or third information of a bandwidth part selected for the SDT procedure.

In some embodiments, the circuitry may be configured to store the information by storing the information in response to at least one of the following: the SDT procedure being a CG-based SDT procedure; an expiration of a first timer configured for detecting the failure of the SDT procedure; or a lower layer of the terminal device indicating the failure of the SDT procedure to a RRC layer of the terminal device.

In some embodiments where the lower layer indicates the failure of the SDT procedure to the RRC layer, the circuitry may be configured to store the information in response to at least one of the following: a MAC layer of the terminal device indicating the failure of a random access procedure for the SDT procedure; the MAC layer indicating a beam failure associated with the SDT procedure; a RLC layer of the terminal device indicating that the number of retransmissions during the SDT procedure reaches a threshold number; or the MAC layer indicating an expiration of a second timer configured for downlink control channel monitoring after a CG transmission for the SDT procedure.

In these embodiments, the information may comprise at least one of the following: fourth information stored for a connection establishment failure report, fifth information of a CG resource selected for a failed CG transmission of the SDT procedure, an index of a SSB selected for the SDT procedure, a measured value of reference signal receive power of the selected SSB when a CG resource is selected, data volume of uplink data to be transmitted when the SDT procedure is triggered, a measured value of reference signal receive power of a serving cell when the SDT procedure is triggered, sixth information regarding phases of the SDT procedure when the failure of the SDT procedure occurs, a cause of the failure of the SDT procedure, an identity of a radio bearer associated with uplink data triggering the SDT procedure and data volume of the radio bearer, a value of a time alignment timer for the SDT procedure when the SDT procedure is triggered, or seventh information of a bandwidth part selected for the SDT procedure.

In some embodiments, the circuitry may be configured to store the information by at least one of the following: storing the information in a variable of the terminal device for a connection establishment failure report; or storing the information in a dedicated variable of the terminal device.

In some embodiments, the circuitry may be configured to transmit the first indication by at least one of the following: transmitting the first indication to the network device in an IE for a connection establishment failure report; or transmitting the first indication to the network device in a dedicated IE.

In some embodiments, a network device comprises a circuitry configured to receive, from a terminal device, a first indication indicating that information of a failed SDT procedure is available. In some embodiments, the circuitry may be further configured to: transmit, to the terminal device, a request for obtaining the information; and receive the information from the terminal device.

In some embodiments, the circuitry may be configured to receive the first indication by at least one of the following: receiving the first indication from the terminal device in an IE for a connection establishment failure report; or receiving the first indication from the terminal device in a dedicated IE.

The term “circuitry” used herein may refer to hardware circuits and/or combinations of hardware circuits and software. For example, the circuitry may be a combination of analog and/or digital hardware circuits with software/firmware. As a further example, the circuitry may be any portions of hardware processors with software including digital signal processor (s) , software, and memory (ies) that work together to cause an apparatus, such as a terminal device or a network device, to perform various functions. In a still further example, the circuitry may be hardware circuits and or processors, such as a microprocessor or a portion of a microprocessor, that requires software/firmware for operation, but the software may not be present when it is not needed for operation. As used herein, the term circuitry also covers an implementation of merely a hardware circuit or processor (s) or a portion of a hardware circuit or processor (s) and its (or their) accompanying software and/or firmware.

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 representation, it will be appreciated that the blocks, apparatus, systems, techniques or methods 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 process or method as described above with reference to FIGs. 1 to 5. 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.

The above program code may be embodied on a machine readable medium, which may be any tangible medium that may contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. The machine readable medium may be a machine readable signal medium or a machine readable storage medium. A machine 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 machine 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 language 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 method of communication, comprising:

in accordance with a determination that a small data transmission (SDT) procedure fails, storing, at a terminal device, information of the failed SDT procedure; and

transmitting, to a network device, a first indication indicating that the information is available.
The method of claim 1, further comprising:

receiving, from the network device, a request for obtaining the information; and

transmitting the information to the network device.
The method of claim 1, further comprising:

discarding the stored information after the information is successfully transmitted to the network device; or

discarding the stored information if a predetermined period of time elapses after the information is added into a variable of the terminal device.
The method of claim 1, wherein storing the information comprises storing the information in response to at least one of the following:

the SDT procedure being a random access (RA) -based SDT procedure;

an expiration of a first timer configured for detecting the failure of the SDT procedure; or

a lower layer of the terminal device indicating the failure of the SDT procedure to a radio resource control (RRC) layer of the terminal device.
The method of claim 4, wherein storing the information in response to the lower layer of the terminal device indicating the failure of the SDT procedure to the RRC layer of the terminal device comprises storing the information in response to at least one of the following:

a media access control (MAC) layer of the terminal device indicating the failure of a random access procedure for the SDT procedure;

the MAC layer indicating a beam failure associated with the SDT procedure; or

a radio link control (RLC) layer of the terminal device indicating that the number of retransmissions during the SDT procedure reaches a threshold number.
The method of claim 4, wherein the information comprises at least one of the following:

first information stored for a connection establishment failure report,

a second indication indicating that the information is for the SDT procedure,

a data volume of uplink data to be transmitted when the SDT procedure is triggered,

a measured value of reference signal receive power of a serving cell when the SDT procedure is triggered,

second information regarding phases of the SDT procedure when the failure of the SDT procedure occurs,

a cause of the failure of the SDT procedure,

an identity of a radio bearer associated with uplink data triggering the SDT procedure and data volume of the radio bearer, or

third information of a bandwidth part selected for the SDT procedure.
The method of claim 6, wherein the first information comprises at least one of the following:

a time stamp which is a period of time elapsed between the storing of the information and the transmission of the first indication,

a global cell identity of a serving cell when the SDT procedure fails,

the latest available radio measurements for an frequency or radio access technology (RAT) ,

the latest detailed location information if available,

an index of a synchronization signal block (SSB) of a downlink beam of a serving cell,

the latest number of consecutive connection failures in the last failed cell the terminal device has experienced independent of RRC state transitions,

radio access channel (RACH) information,

a timing advance command (TAC) of a cell in which the terminal device performs a RA procedure,

the latest wireless local area network (WLAN) measurement results if available,

the latest Bluetooth measurement results if available, or

the latest sensor information if available.
The method of claim 6, wherein the second information comprises at least one of the following:

a third indication indicating whether the failure of the SDT procedure occurs before contention resolution or after successful contention resolution, or

a fourth indication indicating whether the failure of the SDT procedure occurs during a subsequent transmission phase or an initial transmission phase for the SDT procedure.
The method of claim 1, wherein storing the information comprises at least one of the following:

storing the information in a variable of the terminal device for a connection establishment failure report; or

storing the information in a dedicated variable of the terminal device.
The method of claim 1, wherein transmitting the first indication comprises at least one of the following:

transmitting the first indication to the network device in an information element (IE) for a connection establishment failure report; or

transmitting the first indication to the network device in a dedicated information element.
The method of claim 1, wherein storing the information comprises storing the information in response to at least one of the following:

the SDT procedure being a configured grant (CG) -based SDT procedure;

an expiration of a first timer configured for detecting the failure of the SDT procedure; or

a lower layer of the terminal device indicating the failure of the SDT procedure to a radio resource control (RRC) layer of the terminal device.
The method of claim 11, wherein storing the information in response to the lower layer of the terminal device indicating the failure of the SDT procedure to the RRC layer of the terminal device comprises storing the information in response to at least one of the following:

a media access control (MAC) layer of the terminal device indicating the failure of a random access procedure for the SDT procedure;

the MAC layer indicating a beam failure associated with the SDT procedure;

a radio link control (RLC) layer of the terminal device indicating that the number of retransmissions during the SDT procedure reaches a threshold number; or

the MAC layer indicating an expiration of a second timer configured for downlink control channel monitoring after a CG transmission for the SDT procedure.
The method of claim 11, wherein the information comprises at least one of the following:

fourth information stored for a connection establishment failure report,

fifth information of a CG resource selected for a failed CG transmission of the SDT procedure,

an index of a synchronization signal block (SSB) selected for the SDT procedure,

a measured value of reference signal receive power of the selected SSB when a CG resource is selected,

data volume of uplink data to be transmitted when the SDT procedure is triggered,

a measured value of reference signal receive power of a serving cell when the SDT procedure is triggered,

sixth information regarding phases of the SDT procedure when the failure of the SDT procedure occurs,

a cause of the failure of the SDT procedure,

an identity of a radio bearer associated with uplink data triggering the SDT procedure and data volume of the radio bearer,

a value of a time alignment timer for the SDT procedure when the SDT procedure is triggered, or

seventh information of a bandwidth part selected for the SDT procedure.
The method of claim 13, wherein the fourth information comprises at least one of the following:

a time stamp which is a period of time elapsed between the storing of the information and the transmission of the first indication,

a global cell identity of a serving cell when the SDT procedure fails,

the latest available radio measurements for an frequency or radio access technology (RAT) ,

the latest detailed location information if available,

the latest wireless local area network (WLAN) measurement results if available,

the latest Bluetooth measurement results if available, or

the latest sensor information if available.
The method of claim 13, wherein the sixth information comprises at least one of the following:

a fifth indication indicating whether the failure of the SDT procedure occurs during a subsequent transmission phase or an initial transmission phase for the SDT procedure.
The method of claim 6 or 13, wherein the cause of the failure of the SDT procedure comprises at least one of the following:

an expiration of a first timer configured for detecting the failure of the SDT procedure,

a random access problem,

the number of retransmissions reaching a threshold number, or

a beam failure associated with the SDT procedure.
A method of communication, comprising:

receiving, at a network device and from a terminal device, a first indication indicating that information of a failed small data transmission (SDT) procedure is available.
The method of claim 17, further comprising:

transmitting, to the terminal device, a request for obtaining the information; and

receiving the information from the terminal device.
The method of claim 17, wherein the SDT procedure is a random access (RA) -based SDT procedure, and wherein the information comprises at least one of the following:

first information stored for a connection establishment failure report,

a second indication indicating that the information is for the SDT procedure,

a data volume of uplink data to be transmitted when the SDT procedure is triggered,

a measured value of reference signal receive power of a serving cell when the SDT procedure is triggered,

second information regarding phases of the SDT procedure when the failure of the SDT procedure occurs,

a cause of the failure of the SDT procedure,

an identity of a radio bearer associated with uplink data triggering the SDT procedure and data volume of the radio bearer, or

third information of a bandwidth part selected for the SDT procedure.
The method of claim 19, wherein the first information comprises at least one of the following:

a time stamp which is a period of time elapsed between the storing of the information and the transmission of the first indication,

a global cell identity of a serving cell when the SDT procedure fails,

the latest available radio measurements for an frequency or radio access technology (RAT) ,

the latest detailed location information if available,

an index of a synchronization signal block (SSB) of a downlink beam of a serving cell,

the latest number of consecutive connection failures in the last failed cell the terminal device has experienced independent of radio resource control (RRC) state transitions,

radio access channel (RACH) information,

a timing advance command (TAC) of a cell in which the terminal device performs a RA procedure,

the latest wireless local area network (WLAN) measurement results if available,

the latest Bluetooth measurement results if available, or

the latest sensor information if available.
The method of claim 19, wherein the second information comprises at least one of the following:

a third indication indicating whether the failure of the SDT procedure occurs before contention resolution or after successful contention resolution, or

a fourth indication indicating whether the failure of the SDT procedure occurs during a subsequent transmission phase or an initial transmission phase for the SDT procedure.
The method of claim 17, wherein receiving the first indication comprises at least one of the following:

receiving the first indication from the terminal device in an information element (IE) for a connection establishment failure report; or

receiving the first indication from the terminal device in a dedicated information element.
The method of claim 17, wherein the SDT procedure is a configured grant (CG) -based SDT procedure, and wherein the information comprises at least one of the following:

fourth information stored for a connection establishment failure report,

fifth information of a CG resource selected for a failed CG transmission of the SDT procedure,

an index of a synchronization signal block (SSB) selected for the SDT procedure,

a measured value of reference signal receive power of the selected SSB when a CG resource is selected,

data volume of uplink data to be transmitted when the SDT procedure is triggered,

a measured value of reference signal receive power of a serving cell when the SDT procedure is triggered,

sixth information regarding phases of the SDT procedure when the failure of the SDT procedure occurs,

a cause of the failure of the SDT procedure,

an identity of a radio bearer associated with uplink data triggering the SDT procedure and data volume of the radio bearer,

a value of a time alignment timer for the SDT procedure when the SDT procedure is triggered, or

seventh information of a bandwidth part selected for the SDT procedure.
The method of claim 23, wherein the fourth information comprises at least one of the following:

a time stamp which is a period of time elapsed between the storing of the information and the transmission of the first indication,

a global cell identity of a serving cell when the SDT procedure fails,

the latest available radio measurements for an frequency or radio access technology (RAT) ,

the latest detailed location information if available,

the latest wireless local area network (WLAN) measurement results if available,

the latest Bluetooth measurement results if available, or

the latest sensor information if available.
The method of claim 23, wherein the sixth information comprises at least one of the following:

a fifth indication indicating whether the failure of the SDT procedure occurs during a subsequent transmission phase or an initial transmission phase for the SDT procedure.
The method of claim 19 or 23, wherein the cause of the failure of the SDT procedure comprises at least one of the following:

an expiration of a timer configured for detecting the failure of the SDT procedure,

a random access problem,

the number of retransmissions reaching a threshold number, or

a beam failure associated with the SDT procedure.
A terminal device comprising:

a processor configured to perform the method according to any of claims 1 to 16.
A network device comprising:

a processor configured to perform the method according to any of claims 17-26.