Small data transmission failure processing method and apparatus and communication system

Abstract

Embodiments of the present application provide a small data transmission failure processing method and apparatus and a communication system. The small data transmission failure processing apparatus comprises a first processing unit. The first processing unit controls a terminal device and causes the terminal device to execute the following operations: when a first condition is satisfied, for a mobile terminated small data transmission (MT-SDT), determining that no small data transmission (SDT) failure is detected; and / or, when a second condition is satisfied, for a mobile originated small data transmission (MO-SDT), determining that a small data transmission (SDT) failure is detected.

Description

Method, device and communication system for processing small data transmission failure Technical Field

[0001] The embodiments of the present application relate to the field of communication technologies. Background Art

[0002] The Small Data Transmission (SDT) process allows the transmission of data and / or signaling in the Radio Resource Control Inactive (RRC_INACTIVE) state, wherein the RRC_INACTIVE state refers to not entering the Radio Resource Control Connected (RRC_CONNECTED) state.

[0003] In New Radio (NR), up to Release 16 (Rel-16), the RRC_INACTIVE state does not support data transmission. Therefore, the terminal device (e.g., UE) must first restore the connection, transitioning to the RRC_CONNECTED state, for both downlink / terminal (DL / MT) and uplink / terminal-oriented (UL / MO) data transmission. This means that even for infrequent small data transmissions, a connection must be established / restored and then released to the INACTIVE state, resulting in energy consumption and signaling overhead. Infrequent small data transmissions include services from instant messaging services (WhatsApp, QQ, WeChat, etc.), heartbeat services or keep-alive services from instant messaging or email (IM / e-mail) clients and other apps, push notifications from various applications, services from wearable devices (e.g., periodic location information), sensors (e.g., industrial wireless sensor networks sending temperature and pressure readings periodically or in an event-triggered manner), and smart meters (or networks) sending periodic meter readings.

[0004] The signaling overhead of small data packet transmission by inactive UEs is a major issue for more UEs in NR and will become a critical issue not only for network performance and efficiency, but also for UE battery performance. Basically, any device that has occasional small data packets in inactive state will benefit from small data transmission in inactive state.

[0005] It should be noted that the above introduction to the technical background is merely intended to provide a clear and complete description of the technical solutions of this application and facilitate understanding by those skilled in the art. Simply because these solutions are described in the background technology section of this application, it should not be assumed that the above technical solutions are well known to those skilled in the art.

[0006] Summary of the Invention

[0007] The inventors of the present application have discovered that, in the prior art, the processing mechanism for small data transmission failures needs to be further improved.

[0008] In response to at least one of the above problems or other similar problems, embodiments of the present application provide a method, device, and communication system for processing small data transmission failures.

[0009] According to one aspect of an embodiment of the present application, a device for processing a small data transmission failure is provided, which is applied to a terminal device. The device includes a first processing unit, which controls the terminal device to cause the terminal device to perform the following operations:

[0010] When the first condition is met, for a terminal-terminated small data transmission (MT-SDT), it is determined that no small data transmission (SDT) failure is detected; and / or,

[0011] When the second condition is satisfied, for the terminal-oriented small data transmission (MO-SDT), it is determined that a small data transmission (SDT) failure is detected.

[0012] According to another aspect of an embodiment of the present application, a device for processing a small data transmission failure is provided, which is applied to a terminal device. The device includes a second processing unit, which controls the terminal device to cause the terminal device to perform the following operations:

[0013] When the small data transmission (SDT) fails, the terminal device maintains a radio resource control inactive (RRC_INACTIVE) state or enters a radio resource control idle (RRC_IDLE) state.

[0014] According to another aspect of an embodiment of the present application, a device for processing a small data transmission failure is provided, which is applied to a terminal device. The device includes a third processing unit, which controls the terminal device to cause the terminal device to perform the following operations:

[0015] When a small data transmission (SDT) failure is detected for a terminal terminated small data transmission (MT-SDT), a radio resource control establishment (RRC setup) process is initiated.

[0016] One of the beneficial effects of the embodiments of the present application is that it can reduce the downlink data transmission delay when small data transmission fails.

[0017] With reference to the following description and accompanying drawings, specific embodiments of the present application are disclosed in detail, indicating the manner in which the principles of the present application can be employed. It should be understood that the embodiments of the present application are not limited in scope. Within the spirit and scope of the appended claims, the embodiments of the present application include many variations, modifications and equivalents.

[0018] Features described and / or illustrated with respect to one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

[0019] It should be emphasized that the term "include / comprising" when used herein refers to the presence of features, integers, steps or components, but does not exclude the presence or addition of one or more other features, integers, steps or components. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The elements and features described in one figure or one embodiment of the present application can be combined with the elements and features shown in one or more other figures or embodiments. In addition, in the accompanying drawings, similar reference numerals represent corresponding parts in several figures and can be used to indicate corresponding parts used in more than one embodiment.

[0021] FIG1 is a schematic diagram of a communication system of the present application;

[0022] FIG2 is a schematic diagram of a method for processing small data transmission failure according to an embodiment of the first aspect;

[0023] FIG3 is a schematic diagram of a method for processing small data transmission failure according to an embodiment of the second aspect;

[0024] FIG4 is a schematic diagram of a method for processing small data transmission failure according to an embodiment of the third aspect;

[0025] FIG5 is a schematic diagram of a method for processing small data transmission according to an embodiment of the fourth aspect;

[0026] FIG6 is a schematic diagram of a method for processing small data transmission according to an embodiment of the fifth aspect;

[0027] FIG7 is a schematic diagram of a device for processing small data transmission failure according to an embodiment of the sixth aspect;

[0028] FIG8 is another schematic diagram of a device for processing small data transmission failure according to an embodiment of the sixth aspect;

[0029] FIG9 is another schematic diagram of a device for processing small data transmission failure according to an embodiment of the sixth aspect;

[0030] FIG10 is a schematic diagram of a small data transmission processing device according to an embodiment of the sixth aspect;

[0031] FIG11 is a schematic diagram of a small data transmission processing device according to an embodiment of the sixth aspect;

[0032] FIG12 is a schematic diagram of a network device according to an embodiment of the eighth aspect;

[0033] Figure 13 is a schematic diagram of a terminal device of an embodiment of the eighth aspect. DETAILED DESCRIPTION

[0034] The above and other features of the present application will become apparent through the following description with reference to the accompanying drawings. In the description and the accompanying drawings, specific embodiments of the present application are disclosed in detail, which illustrate some embodiments in which the principles of the present application can be adopted. It should be understood that the present application is not limited to the described embodiments. On the contrary, the present application includes all modifications, variations and equivalents that fall within the scope of the appended claims.

[0035] In the embodiments of the present application, the terms "first," "second," etc. are used to distinguish different elements in terms of title, but do not indicate the spatial arrangement or temporal order of these elements, and these elements should not be limited by these terms. The term "and / or" includes any one and all combinations of one or more of the associated listed terms. The terms "comprising," "including," "having," etc. refer to the presence of the stated features, elements, components, or components, but do not exclude the presence or addition of one or more other features, elements, components, or components.

[0036] In the embodiments of this application, the singular forms "a," "the," etc. include plural forms and should be broadly understood to mean "a" or "a type" rather than being limited to "one." Furthermore, the term "said" should be understood to include both singular and plural forms, unless the context clearly indicates otherwise. Furthermore, the term "according to" should be understood to mean "at least in part based on...", and the term "based on" should be understood to mean "at least in part based on...", unless the context clearly indicates otherwise.

[0037] In the embodiments of the present application, the term "communication network" or "wireless communication network" may refer to a network that complies with any of the following communication standards, such as New Radio (NR), Long Term Evolution (LTE), Enhanced Long Term Evolution (LTE-A, LTE-Advanced), Wideband Code Division Multiple Access (WCDMA), High-Speed ​​Packet Access (HSPA), etc.

[0038] Furthermore, communication between devices in the communication system may be carried out according to communication protocols of any stage, for example, including but not limited to the following communication protocols: 1G (generation), 2G, 2.5G, 2.75G, 3G, 4G, 4.5G and 5G, New Radio (NR), etc., and / or other communication protocols currently known or to be developed in the future.

[0039] In the embodiments of the present application, the term "network device" refers to, for example, a device in a communication system that connects a terminal device to a communication network and provides services for the terminal device. Network devices may include, but are not limited to, the following devices: an integrated access and backhaul node (IAB-node), a base station (BS), an access point (AP), a transmission reception point (TRP), a broadcast transmitter, a mobile management entity (MME), a gateway, a server, a radio network controller (RNC), a base station controller (BSC), and the like.

[0040] Base stations may include, but are not limited to, NodeB (NB), evolved NodeB (eNodeB or eNB), and 5G base stations (gNB), among others. They may also include remote radio heads (RRHs), remote radio units (RRUs), relays, or low-power nodes (e.g., femeto, pico, etc.). The term "base station" may include some or all of their functions, and each base station may provide communication coverage for a specific geographic area. The term "cell" may refer to a base station and / or its coverage area, depending on the context in which the term is used.

[0041] In the embodiments of the present application, the term "user equipment" (UE) or "terminal equipment" (TE) refers to, for example, a device that accesses a communication network through a network device and receives network services. A terminal device can be fixed or mobile and may also be referred to as a mobile station (MS), a terminal, a subscriber station (SS), an access terminal (AT), a station, and so on.

[0042] Among them, terminal devices may include but are not limited to the following devices: cellular phones, personal digital assistants (PDAs), wireless modems, wireless communication devices, handheld devices, machine-type communication devices, laptop computers, cordless phones, smart phones, smart watches, digital cameras, etc.

[0043] For another example, in scenarios such as the Internet of Things (IoT), the terminal device can also be a machine or device for monitoring or measurement, including but not limited to: machine type communication (MTC) terminal, vehicle-mounted communication terminal, device-to-device (D2D) terminal, machine-to-machine (M2M) terminal, and so on.

[0044] In addition, the term "network side" or "network device side" refers to one side of the network, which can be a base station or one or more network devices as mentioned above. The term "user side" or "terminal side" or "terminal device side" refers to the user or terminal side, which can be a UE or one or more terminal devices as mentioned above.

[0045] In the following description, the terms "uplink control signal" and "uplink control information (UCI)" or "physical uplink control channel (PUCCH)" are interchangeable, and the terms "uplink data signal" and "uplink data information" or "physical uplink shared channel (PUSCH)" are interchangeable to avoid confusion.

[0046] The terms "downlink control signal" and "downlink control information (DCI)" or "physical downlink control channel (PDCCH)" are interchangeable, and the terms "downlink data signal" and "downlink data information" or "physical downlink shared channel (PDSCH)" are interchangeable.

[0047] In addition, sending or receiving PUSCH can be understood as sending or receiving uplink data carried by PUSCH, sending or receiving PUCCH can be understood as sending or receiving uplink information carried by PUCCH, and sending or receiving PRACH can be understood as sending or receiving preamble carried by PRACH; uplink signals can include uplink data signals and / or uplink control signals, etc., and can also be referred to as uplink transmission (UL transmission) or uplink information or uplink channels. Sending uplink transmission on uplink resources can be understood as sending the uplink transmission using the uplink resources. Similarly, downlink data / signals / channels / information can be understood accordingly.

[0048] In the embodiments of the present application, the high-layer signaling may be, for example, radio resource control (RRC) signaling; for example, an RRC message, including, for example, an MIB, system information, or a dedicated RRC message; or an RRC information element (RRC IE). The high-layer signaling may also be, for example, MAC (Medium Access Control) signaling; or a MAC control element (MAC CE). However, the present application is not limited thereto.

[0049] The following describes the scenarios of the embodiments of the present application through examples, but the present application is not limited thereto.

[0050] Figure 1 is a schematic diagram of the communication system of the present application, which schematically illustrates a situation taking a terminal device and a network device as an example. As shown in Figure 1, the communication system 100 may include a network device 101 and a terminal device 102 (for simplicity, Figure 1 only illustrates one terminal device as an example).

[0051] In the embodiment of the present application, existing services or future services can be carried out between the network device 101 and the terminal device 102. For example, these services include but are not limited to: enhanced mobile broadband (eMBB), massive machine type communication (mMTC), and ultra-reliable and low-latency communication (URLLC), etc.

[0052] Among them, the terminal device 102 can send data to the network device 101, for example, using authorization (for example, a configured authorization, i.e., a configured grant) or an authorization-free transmission mode. In the authorization mode, the network device 101 can receive data sent by one or more terminal devices 102 in the authorization, and feedback information to the terminal device 102, such as confirmation ACK / non-confirmation NACK information, etc., or indicate a new authorization to the terminal device 102. The terminal device 102 can confirm the end of the transmission process based on the feedback information or the new authorization, or can also perform new data transmission, or can retransmit the data. For the authorization-free transmission mode, the terminal device can transmit new data on the configured authorization, or can retransmit.

[0053] The key elements of Small Data Transfer (SDT) in NR, namely the INACTIVE state, 2-step / 4-step random access, and configured grant type 1, have been defined as part of Rel-15 and Rel-16. Therefore, ensuring small data transfer in the INACTIVE state of NR can be based on these elements.

[0054] SDT is enabled on a radio bearer and can be initiated by the UE in the case of mobile-initiated SDT, i.e., mobile-oriented small data transmission (MO-SDT) and / or by the network equipment in the case of mobile-terminated SDT, i.e., mobile-terminated small data transmission (MT-SDT). The network equipment can enable MO-SDT and / or MT-SDT in a cell. MO-SDT is only initiated by the UE if the amount of UL data waiting to be transmitted on all radio bearers with activated SDT is less than the configured value, the DL RSRP is greater than the configured threshold, and valid SDT resources are available. When DL data is waiting for transmission on a radio bearer configured with SDT, MT-SDT is initiated by the network using an indication sent to the UE in a paging message; based on this indication, the UE only initiates MT-SDT if the DL RSRP is greater than the configured threshold.

[0055] The SDT procedure is initiated using transmissions on the Random Access Channel (RACH) or Type 1 Configuration Grant (Type 1CG) resources. RACH can be configured by system information, and Type 1 CG resources can be configured by dedicated signaling in the Radio Resource Control Release (RRCRelease). For both RACH and CG, SDT resources can be configured on the initial bandwidth portion (initial BWP), on non-supplimentary uplink (NUL) carriers, and / or on supplementary uplink (SUL) carriers. The CG resources for SDT are only valid in the UE's primary cell (PCell) upon receipt of an RRCRelease with a hold indication, and are associated with one or more Synchronization Signal / PBCH Blocks (SSBs). SDT on RACH does not support non-contention random access (CFRA). If MT-SDT on RACH is initiated, the UE only uses RACH that is not configured with SDT (i.e., RACH configured for MO-SDT).

[0056] Once initiated, the SDT process is as follows:

[0057] - The SDT procedure is successfully completed after the UE is controlled to enter RRC_IDLE (via RRCRelease) or enter RRC_INACTIVE (via RRCRelease or RRCReject) or enter RRC_CONNECTED (via RRCResume or RRCSetup); or

[0058] - The SDT process completed unsuccessfully.

[0059] Specifically, in response to a UE-initiated recovery procedure for SDT (e.g., the same as a legacy recovery procedure), the network device may:

[0060] -Resume the suspended RRC connection and make the UE enter RRC_CONNECTED. In this case, for example, the UE may: stop T319a if it is running; consider that the SDT process is not in progress; and / or, if SDT MAC / PHY CG is configured (sdt-MAC-PHY-CG-Config), instruct the MAC entity to stop the TA timer (cg-SDT-TimeAlignmentTimer) of the CG-SDT if it is running, and start the TA timer associated with the PTAG if it is not running;

[0061] -Or instruct the UE to initiate NAS-level recovery (for example, in this case, the network device sends an RRCSetup message). When the UE receives the RRCSetup, in this case, the UE may: if the SDT MAC / PHY CG (sdt-MAC-PHY-CG-Config) is configured, the UE instructs the MAC entity to stop the TA timer (cg-SDT-TimeAlignmentTimer) of the CG-SDT if it is running, and start the TA timer associated with the PTAG if it is not running; and / or, if T319a is running, the UE stops T319a; the UE considers that the SDT process is not performed;

[0062] - Or directly release the RRC connection and put the UE into the RRC_IDLE state. In this case, if T319a is running, the UE stops T319a; the UE considers that the SDT process is not in progress;

[0063] - Alternatively, the RRC connection is directly resuspended and the UE enters RRC_INACTIVE. In this case, when the UE receives the RRCRelease message including the suspend configuration (suspendConfig), if SDT (sdt-Config) is configured, the UE may perform at least one of the following operations 1 to 6:

[0064] Operation 1: For each DRB in the SDT DRB list (sdt-DRB-List), the UE considers that the DRB is configured with SDT;

[0065] Operation 2: If SDT SRB2 indication (sdt-SRB2-Indication) is configured, the UE considers that SRB2 is configured with SDT;

[0066] Operation 3: For each unsuspended RLC bearer (except those associated with broadcast MRBs), the UE re-establishes the RLC entity;

[0067] Action 4: For SRB2 (if recovered) and SRB1, the UE triggers the PDCP entity to perform SDU discard;

[0068] Operation 5: If SDT MAC / PHY CG configuration is configured, the UE configures the SDT configured grant (CG) resources for the PCell and instructs the MAC entity to start the TA timer (cg-SDT-TimeAlignmentTimer) of the CG SDT;

[0069] Operation 6: If T319a is running, the UE stops the timer; the UE considers that the SDT process is not in progress.

[0070] Alternatively, the UE may reject the resume request and enter RRC_INACTIVE (with a wait timer). In this case, when the UE receives RRCReject, it may perform at least one of the following operations:

[0071] If timer T319a is running, the UE stops timer T319a;

[0072] The UE considers that the SDT process has not been performed;

[0073] For SRB2, if it is recovered, as for SRB1, the UE triggers the PDCP entity to perform SDU discard and re-establish the RLC entity;

[0074] For each unsuspended DRB, the UE will instruct the PDCP to suspend the lower layers and re-establish the RLC entity;

[0075] The UE suspends SRB1 and radio bearers configured with SDT, if any.

[0076] The above is the processing of the UE in different situations when the SDT process is successfully completed.

[0077] If restoring the RRC connection fails, at least one of the following situations may have occurred:

[0078] -Cell reselection while SDT process is being performed by CG

[0079] -Received an indication from the MCG RLC that the maximum number of retransmissions has been reached while the SDT process is in progress

[0080] -Received the random access problem indication from MCG MAC while the SDT process is in progress

[0081] - The configuredGrantTimer or cg-SDT-TimeAlignmentTimer expires before the lower layer indicates receipt of the network response to the UL CG-SDT transmission carrying the CCCH message while the SDT procedure is in progress

[0082] - An indication of a low-level integrity check failure is received while the SDT process is in progress

[0083] -T319a timeout

[0084] The UE considers that the SDT process has not been carried out and performs the behavior when entering RRC_IDLE, with the release reason being "RRC Resume failure".

[0085] In the embodiments of the present application: SDT and SDT process have the same meaning; "SDT failure" can be replaced by "SDT is not completed successfully"; "SDT (process) failure is detected for MT-SDT" and "MT-SDT (process) failure is detected" have the same meaning; "SDT (process) failure is detected for MO-SDT" and "MO-SDT (process) failure is detected" have the same meaning.

[0086] Embodiments of the first aspect

[0087] The inventors discovered that if the SDT is not successfully completed, according to the existing mechanism, the terminal device (e.g., UE) enters the idle (IDLE) state and waits for paging from the network device; on the network device side, after the random access network (RAN) paging multiple RAN nodes within the RAN paging area has paged multiple times, if no response is received from the terminal device, the network device will assume that the terminal device has entered the IDLE state and initiate core network (CN) paging, which will cause delays in downlink data transmission.

[0088] In order to solve the above problems, an embodiment of the first aspect of the present application provides a method for processing small data transmission failure, which is applied to a terminal device, for example, the terminal device 102 in Figure 1.

[0089] FIG2 is a schematic diagram of a method for processing a small data transmission failure according to an embodiment of the first aspect. As shown in FIG2 , the method for processing a small data transmission failure includes:

[0090] Operation 201: When a first condition is met, for terminal-terminated small data transmission (MT-SDT), it is determined that no small data transmission (SDT) failure is detected; and / or, when a second condition is met, for terminal-oriented small data transmission (MO-SDT), it is determined that a small data transmission (SDT) failure is detected.

[0091] According to the method of the embodiment of the first aspect, MT-SDT or MO-SDT is distinguished to determine whether an SDT failure is detected. Therefore, under normal circumstances, MT-SDT will not detect an SDT failure. In this way, the UE can remain in the RRC_INACTIVE state and continue to receive the next possible RAN paging, thereby avoiding downlink data transmission delays caused by the UE entering the RRC_IDLE state after an SDT failure and being unable to receive RAN paging and having to wait for CN paging.

[0092] In some embodiments of operation 201, not detecting a small data transfer (SDT) failure includes:

[0093] Small data transfer (SDT) is not completed, small data transfer (SDT) is completed, or small data transfer (SDT) is completed successfully.

[0094] In some embodiments of operation 201, detecting a small data transfer (SDT) failure includes:

[0095] A small data transfer (SDT) was not completed successfully, or a small data transfer was completed but not successfully transferred.

[0096] In some embodiments, the first condition includes:

[0097] The terminal device performs cell reselection while a terminal terminated small data transfer (MT-SDT) process is being performed via a configuration grant (CG); and / or

[0098] a first timer or a second timer expires before a lower layer indication of the terminal device receives a response from a network device to an uplink configuration grant small data transmission (UL CG-SDT) carrying a common control channel (CCCH) message, and a terminal-terminated small data transmission (MT-SDT) process is in progress, wherein the first timer is, for example, a configuration grant timer (configuredGrantTimer) and the second timer is, for example, a configuration grant small data transmission timing alignment timer (cg-SDT-TimeAlignmentTimer); and / or

[0099] Receiving an indication from the Master Cell Group Radio Link Control (MCG RLC) that the maximum number of retransmissions has been reached while the MT-SDT procedure is in progress; and / or

[0100] Receiving a random access problem indication from the Master Cell Group Media Access Control (MCG MAC) while the MT-SDT procedure is in progress; and / or

[0101] Receiving an indication that a lower layer integrity check has failed while the MT-SDT procedure is in progress; and / or

[0102] T319a timeout.

[0103] In addition, the present application is not limited to this, and the first condition may also be other conditions.

[0104] In some embodiments, the second condition includes:

[0105] The terminal device performs cell reselection while a small data transmission (MO-SDT) process toward the terminal is being performed through a configuration grant (CG); and / or

[0106] The first timer or the second timer expires before the lower layer indication of the terminal device receives a response from the network device to an uplink configuration grant small data transmission (UL CG-SDT) carrying a common control channel (CCCH) message, and the terminal-oriented small data transmission (MO-SDT) process is in progress, wherein the first timer is, for example, a configuration grant timer (configuredGrantTimer) and the second timer is, for example, a configuration grant small data transmission timing alignment timer (cg-SDT-TimeAlignmentTimer); and / or

[0107] Receiving an indication from the Master Cell Group Radio Link Control (MCG RLC) that the maximum number of retransmissions has been reached while the MO-SDT procedure is in progress; and / or

[0108] Receiving a random access problem indication from the Master Cell Group Media Access Control (MCG MAC) while the MO-SDT procedure is in progress; and / or

[0109] Receiving an indication that a lower layer integrity check has failed while the MO-SDT process is in progress; and / or

[0110] T319a timeout.

[0111] In addition, the present application is not limited to this, and the second condition may also be other conditions.

[0112] In some embodiments, if no small data transmission (SDT) failure is detected in operation 201, the terminal device may initiate a random access procedure. The random access procedure may be random access-based small data transmission (RA-SDT) or traditional random access (legacy RA). In addition, the random access procedure may be two-step random access (2-step RA) or four-step random access (4-step RA).

[0113] In some further embodiments, if no small data transmission (SDT) failure is detected in operation 201, the terminal device may initiate a random access procedure. The random access procedure may be random access-based small data transmission (RA-SDT) or traditional random access (legacy RA). For example, the terminal device considers that small data transmission (SDT) has not been performed and initiates a traditional random access procedure. In addition, the random access procedure may be two-step random access (2-step RA) or four-step random access (4-step RA).

[0114] In other embodiments, when no small data transmission (SDT) failure is detected in operation 201, the terminal device considers that no configuration-granted small data transmission (CG-SDT) is performed, and a random access procedure may be initiated. The random access procedure may be random access-based small data transmission (RA-SDT) or legacy random access (legacy RA). In addition, the random access procedure may be two-step random access (2-step RA) or four-step random access (4-step RA).

[0115] During the random access process initiated by the terminal device, the terminal device may:

[0116] Obtaining a media access control protocol data unit (MAC PDU) from an automatic repeat request buffer (HARQ buffer); and / or placing the obtained media access control protocol data unit (MAC PDU) into an Msg3 buffer or an MsgA buffer.

[0117] As shown in FIG2 , the method for processing the small data transmission failure further includes:

[0118] Operation 202: When it is determined that a small data transmission (SDT) failure is detected, the terminal device maintains a radio resource control inactive (RRC_INACTIVE) state or enters a radio resource control idle (RRC_IDLE) state.

[0119] In operation 202: for example, when the small data transmission (SDT) is a terminal-oriented small data transmission (MO-SDT), when it is determined that a small data transmission (SDT) failure is detected, the terminal device enters a radio resource control idle (RRC_IDLE) state; for another example, when the small data transmission (SDT) is a terminal-terminated small data transmission (MT-SDT), when it is determined that a small data transmission (SDT) failure is detected, the terminal device remains in a radio resource control inactive (RRC_INACTIVE) state.

[0120] As shown in FIG2 , the method for processing the small data transmission failure further includes:

[0121] Operation 203: When a small data transmission (SDT) failure is detected for the terminal-terminated small data transmission (MT-SDT), a radio resource control setup (RRC setup) process is initiated.

[0122] In operation 203, a radio resource control (RRC setup) process is initiated, which may include at least one of the following at least two solutions:

[0123] Solution 1: The radio resource control (RRC) layer of the terminal device initiates the radio resource control (RRC setup) process;

[0124] Solution 2: The radio resource control (RRC) layer of the terminal device indicates the failure to the non-access stratum (NAS).

[0125] In solution 1, for example, when a small data transfer (SDT) failure is detected for a terminal-terminated small data transfer (MT-SDT), the terminal device enters the radio resource control idle (RRC_IDLE) state and initiates a radio resource control (RRC setup) procedure. The cause of initiating the radio resource control (RRC setup) procedure may be a terminal-terminated access (MT-access).

[0126] In Scheme 2, for example, when a small data transmission (SDT) failure is detected for a terminal-terminated small data transmission (MT-SDT), the failure is indicated by the radio resource control (RRC) layer of the terminal device to the non-access stratum (NAS), and the terminal device enters a radio resource control idle (RRC_IDLE) state, where the release reason is the small data transmission (SDT) failure.

[0127] In some embodiments of Solution 2, based on the indication of the failure by the radio resource control (RRC) layer of the terminal device to the non-access stratum (NAS), the following operations may also be performed:

[0128] The non-access stratum (NAS) instructs the AS to initiate the radio resource control establishment (RRC setup) process; or, based on the indication of the above failure, the non-access stratum (NAS) instructs the AS to initiate the radio resource control establishment (RRC setup) process.

[0129] In this way, the RRC setup process can be initiated.

[0130] Embodiments of the second aspect

[0131] In order to solve a problem similar to that in the embodiment of the first aspect, an embodiment of the second aspect of the present application provides a method for processing small data transmission failure, which is applied to a terminal device, for example, the terminal device 102 in Figure 1.

[0132] FIG3 is a schematic diagram of a method for processing small data transmission failure according to an embodiment of the second aspect.

[0133] As shown in FIG3 , the method for handling the small data transmission failure includes:

[0134] Operation 301: When it is determined that a small data transmission (SDT) failure is detected, the terminal device maintains a radio resource control inactive (RRC_INACTIVE) state or enters a radio resource control idle (RRC_IDLE) state.

[0135] In operation 301: for example, when the small data transmission (SDT) is a terminal-oriented small data transmission (MO-SDT), when it is determined that a small data transmission (SDT) failure is detected, the terminal device enters a radio resource control idle (RRC_IDLE) state; for another example, when the small data transmission (SDT) is a terminal-terminated small data transmission (MT-SDT), when it is determined that a small data transmission (SDT) failure is detected, the terminal device remains in a radio resource control inactive (RRC_INACTIVE) state.

[0136] According to an embodiment of the second aspect, when an SDT failure is detected, MO-SDT and MT-SDT are processed differently, thereby shortening the delay of downlink data transmission.

[0137] Embodiments of the third aspect

[0138] In order to solve a problem similar to that in the embodiment of the first aspect, an embodiment of the third aspect of the present application provides a method for processing failure of small data transmission, which is applied to a terminal device, for example, the terminal device 102 in Figure 1.

[0139] FIG4 is a schematic diagram of a method for processing a small data transmission failure according to an embodiment of the third aspect. As shown in FIG4 , the method for processing a small data transmission failure includes:

[0140] Operation 401: When a small data transmission (SDT) failure is detected for a terminal-terminated small data transmission (MT-SDT), a radio resource control (RRC setup) process is initiated.

[0141] In operation 401, a radio resource control (RRC setup) process is initiated, which may include at least one of the following at least two solutions:

[0142] Solution 1: The radio resource control (RRC) layer of the terminal device initiates the radio resource control (RRC setup) process;

[0143] Solution 2: The radio resource control (RRC) layer of the terminal device indicates the failure to the non-access stratum (NAS).

[0144] In solution 1, for example, when a small data transfer (SDT) failure is detected for a terminal-terminated small data transfer (MT-SDT), the terminal device enters the radio resource control idle (RRC_IDLE) state and initiates a radio resource control (RRC setup) procedure. The cause of initiating the radio resource control (RRC setup) procedure may be a terminal-terminated access (MT-access).

[0145] In solution 2, for example, when a small data transfer (SDT) failure is detected for a terminal-terminated small data transfer (MT-SDT), the radio resource control (RRC) layer of the terminal device indicates the failure to the non-access stratum (NAS), and the terminal device enters a radio resource control idle (RRC_IDLE) state. In some embodiments of solution 2, the release reason is the small data transfer (SDT) failure.

[0146] In some embodiments of Solution 2, based on the indication of the failure by the radio resource control (RRC) layer of the terminal device to the non-access stratum (NAS), the following operations may also be performed:

[0147] The non-access stratum (NAS) instructs the AS to initiate the radio resource control establishment (RRC setup) process; or, based on the indication of the above failure, the non-access stratum (NAS) instructs the AS to initiate the radio resource control establishment (RRC setup) process.

[0148] In this way, the RRC setup process can be initiated.

[0149] According to an embodiment of the third aspect, when MT-SDT failure is detected, an RRC setup process is initiated, thereby shortening the delay of downlink data transmission.

[0150] Embodiments of the fourth aspect

[0151] An embodiment of the fourth aspect of the present application provides a method for processing small data transmission, which is applied to a terminal device, for example, the terminal device 102 in Figure 1.

[0152] FIG5 is a schematic diagram of a method for processing small data transmission according to an embodiment of the fourth aspect. As shown in FIG5 , the method for processing small data transmission includes:

[0153] Operation 501: When signaling radio bearer 1 (SRB1) is configured with small data transmission (SDT) and / or any data radio bearer (DRB) is not configured with small data transmission (SDT), receive a downlink (DL) message sent by a network device and the downlink (DL) data carried in the downlink (DL) message.

[0154] In an embodiment of the fourth aspect, in the case of SDT, the terminal device receives DL data carried in the DL message, thereby improving the data transmission efficiency during the SDT process.

[0155] In some embodiments of operation 501, when signaling radio bearer 1 (SRB1) is configured with small data transmission (SDT) and / or any data radio bearer (DRB) is not configured with small data transmission (SDT), and there is no uplink data available, a downlink (DL) message sent by a network device and the downlink (DL) data carried in the downlink (DL) message are received.

[0156] In some embodiments, as shown in FIG5 , the method further includes:

[0157] Operation 502: When the downlink (DL) message is an RRC resume message, that is, when the network device resumes the suspended radio resource control (RRC) connection and causes the terminal device to enter a radio resource control connected (RRC_CONNECTED) state, the terminal device performs at least one of the following operations:

[0158] Stop the running timer T319a; and

[0159] If predetermined parameters are configured, instruct the media access control (MAC) entity to: stop the time alignment (TA) timer (e.g., cg-SDT-TimeAlignmentTimer) of the configured grant-based small data transfer (CG-SDT) that is running, or to start the time alignment (TA) timer associated with the primary timing advance group (PTAG) that is not running.

[0160] The predetermined parameter in operation 502 may be a small data transmission media access control layer / physical layer configuration grant (SDT MAC / PHY CG), and a specific name of the predetermined parameter is, for example, sdt-MAC-PHY-CG-Config.

[0161] In some embodiments, as shown in FIG5 , the method further includes:

[0162] Operation 503: When the downlink (DL) message is an RRC establishment message, that is, when an indication of initiating non-access stratum (NAS) level recovery sent by the network device is received, the terminal device performs at least one of the following operations:

[0163] If a predetermined parameter is configured, instructing a medium access control (MAC) entity to: stop a running time alignment (TA) timer (e.g., cg-SDT-TimeAlignmentTimer) of a configuration-grant-based small data transfer (CG-SDT), or to start a non-running time alignment (TA) timer associated with a primary timing advance group (PTAG); and

[0164] Stop the running timer T319a.

[0165] The predetermined parameter in operation 503 may be a small data transmission media access control layer / physical layer configuration authorization (SDT MAC / PHY CG), and a specific name of the predetermined parameter is, for example, sdt-MAC-PHY-CG-Config.

[0166] In some embodiments, as shown in FIG5 , the method further includes:

[0167] Operation 504: When the downlink (DL) message is an RRC release message, that is, the radio resource control (RRC) connection is released and the terminal device enters a radio resource control idle (RRC_IDLE) state, the terminal device performs the following operations:

[0168] Stop the running timer T319a.

[0169] In some embodiments, as shown in FIG5 , the method further includes:

[0170] Operation 505: The method further includes:

[0171] In a case where the downlink (DL) message is an RRC release message including a suspend configuration (suspendConfig), that is, when the terminal device receives a radio resource control release (RRCRelease) message including a suspend configuration (suspendConfig), if small data transmission (SDT) is configured, the terminal device performs at least one of the following operations:

[0172] For each data radio bearer (DRB) in the small data transmission data radio bearer (SDT DRB) list, the terminal device considers that the data radio bearer (DRB) is configured with small data transmission (SDT);

[0173] If a small data transmission signaling radio bearer 2 (SDT SRB2) indication is configured, the terminal device considers that the signaling radio bearer 2 (SRB2) is configured with small data transmission (SDT);

[0174] For at least one unsuspended radio link control (RLC) bearer, the terminal device re-establishes a radio link control (RLC) entity;

[0175] For the restored signaling radio bearer 2 (SRB2) and signaling radio bearer 1 (SRB1), the terminal device triggers a packet data convergence protocol (PDCP) entity to perform service data unit (SDU) discard;

[0176] If the predetermined parameters are configured, the terminal device configures a configuration grant (CG) resource for the small data transmission (SDT) for the primary cell (PCell), and instructs a medium access control (MAC) entity to start a TA timer (e.g., cg-SDT-TimeAlignmentTimer) for the configuration grant small data transmission (CG SDT); and

[0177] Stop the running timer T319a.

[0178] In some embodiments, as shown in FIG5 , the method further includes:

[0179] Operation 506: When the downlink (DL) message is an RRC reject message, that is, when a radio resource control reject (RRCReject) message for rejecting a resumption request of a small data transmission (SDT) process is received, the terminal device performs at least one of the following operations:

[0180] Stop the running timer T319a;

[0181] For the restored signaling radio bearer 2 (SRB2) and signaling radio bearer 1 (SRB1), the terminal device triggers a packet data convergence protocol (PDCP) entity to discard a service data unit (SDU) and re-establish a radio link control (RLC) entity;

[0182] For at least one unsuspended data radio bearer (DRB), the terminal device instructs a packet data convergence protocol (PDCP) to suspend a lower layer and re-establish a radio link control (RLC) entity; and

[0183] Suspend Signalling Radio Bearer 1 (SRB1) and radio bearers configured with Small Data Transport (SDT).

[0184] Embodiments of the fifth aspect

[0185] The fifth embodiment of the present application provides a method for processing small data transmission, which is applied to a network device, such as the terminal device 101 in Figure 1. The method for processing small data transmission in the fifth embodiment corresponds to the method for processing small data transmission in the fourth embodiment.

[0186] FIG6 is a schematic diagram of a method for processing small data transmission according to an embodiment of the fifth aspect. As shown in FIG6 , the method for processing small data transmission includes:

[0187] Operation 601: Carry downlink (DL) data in a downlink (DL) message when signaling radio bearer 1 (SRB1) is configured with small data transmission (SDT) and / or any data radio bearer (DRB) is not configured with small data transmission (SDT).

[0188] In some embodiments of operation 601, when signaling radio bearer 1 (SRB1) is configured with small data transmission (SDT) and / or any data radio bearer (DRB) is not configured with small data transmission (SDT), and there is no uplink data available, downlink (DL) data is carried in a downlink (DL) message.

[0189] In some embodiments:

[0190] The downlink (DL) message is used to resume a suspended radio resource control (RRC) connection and enable the terminal device to enter the radio resource control connected (RRC_CONNECTED) state; or

[0191] The downlink (DL) message is used to instruct the terminal device to initiate non-access stratum (NAS) level recovery; or

[0192] The downlink (DL) message is used to release the radio resource control (RRC) connection and enable the terminal device to enter a radio resource control idle (RRC_IDLE) state; or

[0193] The downlink (DL) message is used to re-suspend the radio resource control (RRC) connection and cause the terminal device to enter a radio resource control inactive (RRC_INACTIVE) state; or

[0194] The downlink (DL) message is used to reject the resumption request of the small data transmission (SDT) process and enable the terminal device to enter the radio resource control inactive (RRC_INACTIVE) state.

[0195] In an embodiment of the fifth aspect, in the case of SDT, the network device can send DL data through a DL message, thereby improving data transmission efficiency during the SDT process.

[0196] Embodiments of the sixth aspect

[0197] The sixth aspect of the present application provides a device for processing small data transmission failure, which is applied to a terminal device, such as the terminal device 102 in Figure 1. The device for processing small data transmission failure corresponds to the method for processing small data transmission failure in the first aspect of the present application.

[0198] FIG7 is a schematic diagram of a device for processing a small data transmission failure according to an embodiment of the sixth aspect. As shown in FIG7 , the device 700 includes a first processing unit 701. The first processing unit 701 controls the terminal device to cause the terminal device to perform the following operations:

[0199] When the first condition is met, for a terminal-terminated small data transmission (MT-SDT), it is determined that no small data transmission (SDT) failure is detected; and / or,

[0200] When the second condition is satisfied, for the terminal-oriented small data transmission (MO-SDT), it is determined that a small data transmission (SDT) failure is detected.

[0201] In some embodiments, no small data transfer (SDT) failure is detected, including:

[0202] Small data transfer (SDT) is not completed, small data transfer (SDT) is completed, or small data transfer (SDT) is completed successfully.

[0203] In some embodiments, detecting a small data transfer (SDT) failure includes:

[0204] A small data transfer (SDT) was not completed successfully or a small data transfer was completed but not successfully transferred.

[0205] In some embodiments, the first condition includes:

[0206] The terminal device performs cell reselection while a terminal terminated small data transfer (MT-SDT) process is being performed via a configuration grant (CG); and / or

[0207] The first timer or the second timer times out before the lower layer indication of the terminal device receives the response of the network device to the small data transmission (UL CG-SDT) with uplink configuration authorization carrying the common control channel (CCCH) message, and the small data transmission (MT-SDT) process terminated by the terminal is in progress.

[0208] In some embodiments, the second condition includes:

[0209] Receiving an indication from a Master Cell Group Radio Link Control (MCG RLC) that a maximum number of retransmissions has been reached while a Small Data Transfer (MO-SDT) procedure toward the terminal is in progress; and / or

[0210] A random access problem indication of a master cell group medium access control (MCG MAC) is received while a MO-SDT procedure of the terminal is in progress.

[0211] In some embodiments, no small data transfer (SDT) failure is detected, including:

[0212] The terminal device initiates a random access process.

[0213] In some embodiments, the terminal device initiates a random access process, including:

[0214] Obtaining a Media Access Control Protocol Data Unit (MAC PDU) from an Automatic Repeat Request Buffer (HARQ buffer); and / or

[0215] The acquired media access control protocol data unit (MAC PDU) is placed into the Msg3 buffer or the MsgA buffer.

[0216] In some embodiments, the operations further include:

[0217] When it is determined that a small data transmission (SDT) failure is detected, the terminal device maintains a radio resource control inactive (RRC_INACTIVE) state or enters a radio resource control idle (RRC_IDLE) state.

[0218] In some embodiments, when the small data transmission (SDT) is a terminal-oriented small data transmission (MO-SDT), the terminal device enters a radio resource control idle (RRC_IDLE) state; or

[0219] When the small data transmission (SDT) is a terminal terminated small data transmission (MT-SDT), the terminal device remains in a radio resource control inactive (RRC_INACTIVE) state.

[0220] In some embodiments, the operations further include:

[0221] When a small data transmission (SDT) failure is detected for a terminal terminated small data transmission (MT-SDT), a radio resource control establishment (RRC setup) process is initiated.

[0222] In some embodiments, initiating a radio resource control (RRC setup) procedure includes:

[0223] The radio resource control (RRC setup) process is initiated by the radio resource control (RRC) layer of the terminal device; or

[0224] The failure is indicated by a radio resource control (RRC) layer of the terminal device to a non-access stratum (NAS).

[0225] In some embodiments, the radio resource control (RRC setup) process is initiated by a radio resource control (RRC) layer of the terminal device, including:

[0226] When a small data transmission (SDT) failure is detected for a terminal terminated small data transmission (MT-SDT), the terminal device enters a radio resource control idle (RRC_IDLE) state and initiates the radio resource control establishment (RRC setup) process.

[0227] In some embodiments, a cause for initiating the radio resource control (RRC setup) procedure is a terminal terminated access (MT-access).

[0228] In some embodiments, the radio resource control (RRC) layer of the terminal device indicates the failure to a non-access stratum (NAS), including:

[0229] When a small data transmission (SDT) failure is detected for a terminal terminated small data transmission (MT-SDT), the terminal device enters a radio resource control idle (RRC_IDLE) state, wherein the release reason is the small data transmission (SDT) failure.

[0230] In some embodiments, the initiating radio resource control establishment (RRC setup) process further includes:

[0231] Based on the indication, the non-access stratum (NAS) instructs the AS to initiate the radio resource control establishment (RRC setup) process.

[0232] The sixth aspect of the present application further provides a device for processing small data transmission failures, which is applied to a terminal device, such as the terminal device 102 in Figure 1. The device for processing small data transmission failures corresponds to the method for processing small data transmission failures in the second aspect of the present application.

[0233] FIG8 is another schematic diagram of a device for processing a small data transmission failure according to an embodiment of the sixth aspect. As shown in FIG8 , the device 800 includes a second processing unit 801. The second processing unit 801 controls the terminal device to cause the terminal device to perform the following operations:

[0234] When the small data transmission (SDT) fails, the terminal device maintains a radio resource control inactive (RRC_INACTIVE) state or enters a radio resource control idle (RRC_IDLE) state.

[0235] In some embodiments, when the small data transmission (SDT) is a terminal-oriented small data transmission (MO-SDT), the terminal device enters a radio resource control idle (RRC_IDLE) state; or

[0236] When the small data transmission (SDT) is a terminal terminated small data transmission (MT-SDT), the terminal device remains in a radio resource control inactive (RRC_INACTIVE) state.

[0237] The sixth aspect of the present application further provides a device for processing small data transmission failures, which is applied to a terminal device, such as the terminal device 102 in Figure 1. The device for processing small data transmission failures corresponds to the method for processing small data transmission failures in the third aspect of the present application.

[0238] FIG9 is another schematic diagram of a device for processing a small data transmission failure according to an embodiment of the sixth aspect. As shown in FIG9 , the device 900 includes a third processing unit 901. The third processing unit 901 controls the terminal device to cause the terminal device to perform the following operations:

[0239] When a small data transmission (SDT) failure is detected for a terminal terminated small data transmission (MT-SDT), a radio resource control establishment (RRC setup) process is initiated.

[0240] In some embodiments, initiating a radio resource control (RRC setup) procedure includes:

[0241] The radio resource control (RRC setup) process is initiated by the radio resource control (RRC) layer of the terminal device; or

[0242] The failure is indicated by a radio resource control (RRC) layer of the terminal device to a non-access stratum (NAS).

[0243] In some embodiments, the radio resource control (RRC setup) process is initiated by a radio resource control (RRC) layer of the terminal device, including:

[0244] When a small data transmission (SDT) failure is detected for a terminal terminated small data transmission (MT-SDT), the terminal device enters a radio resource control idle (RRC_IDLE) state and initiates the radio resource control establishment (RRC setup) process.

[0245] In some embodiments, a cause for initiating the radio resource control (RRC setup) procedure is a terminal terminated access (MT-access).

[0246] In some embodiments, indicating, by a radio resource control (RRC) layer of the terminal device, the failure to a non-access stratum (NAS), comprises:

[0247] When a small data transmission (SDT) failure is detected for a terminal terminated small data transmission (MT-SDT), the terminal device enters a radio resource control idle (RRC_IDLE) state, wherein the release reason is the small data transmission (SDT) failure.

[0248] In some embodiments, initiating a radio resource control (RRC setup) process further includes:

[0249] Based on the indication, the non-access stratum (NAS) initiates the radio resource control establishment (RRC setup) process.

[0250] The embodiment of the sixth aspect of the present application further provides a small data transmission processing device, which is applied to a terminal device, for example, the terminal device 102 in Figure 1. The small data transmission processing device corresponds to the small data transmission processing method of the embodiment of the fourth aspect.

[0251] FIG10 is a schematic diagram of a processing device for small data transmission according to an embodiment of the sixth aspect. As shown in FIG10 , the device 1000 includes a fourth processing unit 1001. The fourth processing unit 1001 controls the terminal device so that the terminal device performs the following operations:

[0252] When signaling radio bearer 1 (SRB1) is configured with small data transmission (SDT) and / or any data radio bearer (DRB) is not configured with small data transmission (SDT), a downlink (DL) message sent by a network device and the downlink (DL) data carried in the downlink (DL) message are received.

[0253] In some embodiments, the above operations are, for example:

[0254] When signaling radio bearer 1 (SRB1) is configured with small data transmission (SDT) and / or any data radio bearer (DRB) is not configured with small data transmission (SDT) and there is no uplink available data, a downlink (DL) message sent by a receiving network device and the downlink (DL) data carried in the downlink (DL) message.

[0255] In some embodiments, the operations further include:

[0256] In a case where the network device resumes a suspended radio resource control (RRC) connection and causes the terminal device to enter a radio resource control connected (RRC_CONNECTED) state, the terminal device performs at least one of the following operations:

[0257] Stop the running timer T319a; and

[0258] If predetermined parameters are configured, instruct the media access control (MAC) entity to: stop the time alignment (TA) timer of the configured authorization-based small data transmission (CG-SDT) that is running, or start the time alignment (TA) timer associated with the primary timing advance group (PTAG) that is not running.

[0259] In some embodiments, the operations further include:

[0260] Upon receiving an indication from the network device to initiate non-access stratum (NAS) level recovery, the terminal device performs at least one of the following operations:

[0261] If the predetermined parameters are configured, instructing the medium access control (MAC) entity to: stop the time alignment (TA) timer of the configuration grant-based small data transmission (CG-SDT) that is running, or start the time alignment (TA) timer associated with the primary timing advance group (PTAG) that is not running; and

[0262] Stop the running timer T319a.

[0263] In some embodiments, the operations further include:

[0264] The radio resource control (RRC) connection is released and the terminal device enters a radio resource control idle (RRC_IDLE) state, and the terminal device performs the following operations:

[0265] Stop the running timer T319a.

[0266] In some embodiments, the operations further include:

[0267] When the terminal device receives a radio resource control release (RRCRelease) message including a suspend configuration (suspendConfig), if small data transmission (SDT) is configured, the terminal device performs at least one of the following operations:

[0268] For each data radio bearer (DRB) in the small data transmission data radio bearer (SDT DRB) list, the terminal device considers that the data radio bearer (DRB) is configured with small data transmission (SDT);

[0269] If a small data transmission signaling radio bearer 2 (SDT SRB2) indication is configured, the terminal device considers that the signaling radio bearer 2 (SRB2) is configured with small data transmission (SDT);

[0270] For at least one unsuspended radio link control (RLC) bearer, the terminal device re-establishes a radio link control (RLC) entity;

[0271] For the restored signaling radio bearer 2 (SRB2) and signaling radio bearer 1 (SRB1), the terminal device triggers a packet data convergence protocol (PDCP) entity to perform service data unit (SDU) discard;

[0272] If the predetermined parameters are configured, the terminal device configures a configuration grant (CG) resource of the small data transmission (SDT) for the primary cell (PCell), and instructs a medium access control (MAC) entity to start a TA timer of the configuration grant small data transmission (CG SDT); and

[0273] Stop the running timer T319a.

[0274] In some embodiments, the operations further include:

[0275] Upon receiving a radio resource control reject (RRCReject) message for rejecting a resume request of a small data transfer (SDT) process, the terminal device performs at least one of the following operations:

[0276] Stop the running timer T319a;

[0277] For the restored signaling radio bearer 2 (SRB2) and signaling radio bearer 1 (SRB1), the terminal device triggers a packet data convergence protocol (PDCP) entity to discard a service data unit (SDU) and re-establish a radio link control (RLC) entity;

[0278] For at least one unsuspended data radio bearer (DRB), the terminal device instructs a packet data convergence protocol (PDCP) to suspend a lower layer and re-establish a radio link control (RLC) entity; and

[0279] Suspend Signalling Radio Bearer 1 (SRB1) and radio bearers configured with Small Data Transport (SDT).

[0280] Embodiments of the seventh aspect

[0281] The seventh aspect of the present application provides a small data transmission processing device, which is applied to a network device, such as the network device 101 in Figure 1. The small data transmission processing device corresponds to the small data transmission processing method of the fifth aspect.

[0282] FIG11 is a schematic diagram of a processing device for small data transmission according to an embodiment of the sixth aspect. As shown in FIG11 , the device 1100 includes a fifth processing unit 1101. The fifth processing unit 1101 controls the network device to cause the network device to perform the following operations:

[0283] When signaling radio bearer 1 (SRB1) is configured with small data transmission (SDT) and / or any data radio bearer (DRB) is not configured with small data transmission (SDT), downlink (DL) data is carried in a downlink (DL) message.

[0284] In some embodiments, the above operation is, for example: sending a downlink (DL) message carrying downlink (DL) data when signaling radio bearer 1 (SRB1) is configured with small data transmission (SDT) and / or any data radio bearer (DRB) is not configured with small data transmission (SDT), and there is no uplink available data.

[0285] In some embodiments, the downlink (DL) message is used to resume a suspended radio resource control (RRC) connection and cause the terminal device to enter a radio resource control connected (RRC_CONNECTED) state; or

[0286] The downlink (DL) message is used to instruct the terminal device to initiate non-access stratum (NAS) level recovery; or

[0287] The downlink (DL) message is used to release the radio resource control (RRC) connection and enable the terminal device to enter a radio resource control idle (RRC_IDLE) state; or

[0288] The downlink (DL) message is used to re-suspend the radio resource control (RRC) connection and cause the terminal device to enter a radio resource control inactive (RRC_INACTIVE) state; or

[0289] The downlink (DL) message is used to reject the resumption request of the small data transmission (SDT) process and enable the terminal device to enter the radio resource control inactive (RRC_INACTIVE) state.

[0290] Embodiments of the eighth aspect

[0291] An embodiment of the eighth aspect of the present application provides a communication system, which may include a network device and a terminal device.

[0292] FIG12 is a schematic diagram of a network device according to an embodiment of the eighth aspect. As shown in FIG12 , network device 1200 (e.g., corresponding to network device 201 in FIG2 ) may include a processor 1210 (e.g., a central processing unit (CPU)) and a memory 1220; the memory 1220 is coupled to the processor 1210. The memory 1220 may store various data and may also store an information processing program 1230, which is executed under the control of the processor 1212.

[0293] For example, the processor 1212 can be configured to execute a program to implement the method as described in the embodiment of the fifth aspect.

[0294] In addition, as shown in FIG12 , network device 1200 may further include: a transceiver 1240 and an antenna 1250, etc.; wherein, the functions of the above components are similar to those in the prior art and are not described in detail here. It is worth noting that network device 1200 does not necessarily include all the components shown in FIG12 ; in addition, network device 1200 may also include components not shown in FIG12 , and reference may be made to the prior art for details.

[0295] FIG13 is a schematic diagram of a terminal device according to an embodiment of the eighth aspect. As shown in FIG13 , the terminal device 1300 (e.g., corresponding to the terminal device 102 in FIG1 ) may include a processor 1310 and a memory 1320; the memory 1320 stores data and programs and is coupled to the processor 1310. It should be noted that this diagram is exemplary; other types of structures may be used to supplement or replace this structure to implement telecommunication functions or other functions.

[0296] For example, the processor 1310 can be configured to execute a program to implement the method in the first aspect embodiment and / or the method in the second aspect embodiment and / or the method in the third aspect embodiment and / or the method in the fourth aspect embodiment.

[0297] As shown in Figure 13 , the terminal device 1300 may further include: a communication module 1330, an input unit 1340, a display 1350, and a power supply 1360. The functions of these components are similar to those in the prior art and are not described in detail here. It is worth noting that the terminal device 1300 does not necessarily include all of the components shown in Figure 13 , and these components are not essential. Furthermore, the terminal device 1300 may also include components not shown in Figure 13 , for which reference may be made to the prior art.

[0298] An embodiment of the present application also provides a computer program, wherein when the program is executed in a terminal device, the program causes the terminal device to execute at least one method in the embodiments of the first to fourth aspects.

[0299] An embodiment of the present application also provides a storage medium storing a computer program, wherein the computer program enables a terminal device to execute at least one method of the embodiments of the first to fourth aspects.

[0300] An embodiment of the present application also provides a computer program, wherein when the program is executed in a network device, the program causes the network device to execute the method in the embodiment of the fifth aspect.

[0301] An embodiment of the present application also provides a storage medium storing a computer program, wherein the computer program enables a network device to execute the method in the embodiment of the fifth aspect.

[0302] The above devices and methods of the present application can be implemented by hardware or by a combination of hardware and software. The present application relates to such a computer-readable program that, when executed by a logic component, enables the logic component to implement the devices or components described above, or enables the logic component to implement the various methods or steps described above. The present application also relates to a storage medium for storing the above program, such as a hard disk, a magnetic disk, an optical disk, a DVD, a flash memory, etc.

[0303] The method / device described in conjunction with the embodiments of the present application can be directly embodied as hardware, a software module executed by a processor, or a combination of the two. For example, one or more of the functional block diagrams shown in the figure and / or one or more combinations of functional block diagrams can correspond to various software modules of the computer program flow or to various hardware modules. These software modules can respectively correspond to the various steps shown in the figure. These hardware modules can be implemented by solidifying these software modules, for example, using a field programmable gate array (FPGA).

[0304] The software module may be located in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. A storage medium may be coupled to a processor so that the processor can read information from the storage medium and write information to the storage medium; or the storage medium may be an integral part of the processor. The processor and the storage medium may be located in an ASIC. The software module may be stored in the memory of the mobile terminal or in a memory card that can be inserted into the mobile terminal. For example, if the device (such as a mobile terminal) uses a large-capacity MEGA-SIM card or a large-capacity flash memory device, the software module may be stored in the MEGA-SIM card or the large-capacity flash memory device.

[0305] One or more of the functional blocks and / or one or more combinations of functional blocks described in the accompanying drawings may be implemented as a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, or any appropriate combination thereof for performing the functions described in this application. One or more of the functional blocks and / or one or more combinations of functional blocks described in the accompanying drawings may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in communication with a DSP, or any other such configuration.

[0306] The present application has been described above in conjunction with specific embodiments. However, those skilled in the art should understand that these descriptions are merely illustrative and are not intended to limit the scope of protection of the present application. Those skilled in the art may make various modifications and variations to the present application based on the spirit and principles of the present application, and such modifications and variations are also within the scope of the present application.

[0307] Regarding the implementation methods including the above embodiments, the following additional notes are also disclosed:

[0308] The terminal side method of the first aspect embodiment:

[0309] 1. A method for processing a small data transmission failure, applied to a terminal device, comprising:

[0310] When the first condition is met, for a terminal-terminated small data transmission (MT-SDT), it is determined that no small data transmission (SDT) failure is detected; and / or,

[0311] When the second condition is satisfied, for the terminal-oriented small data transmission (MO-SDT), it is determined that a small data transmission (SDT) failure is detected.

[0312] 1a. The method as described in Note 1, wherein:

[0313] No small data transfer (SDT) failures were detected, including:

[0314] Small data transfer (SDT) is not completed, small data transfer (SDT) is completed, or small data transfer (SDT) is completed successfully.

[0315] 1b. The method as described in Note 1, wherein:

[0316] Small Data Transfer (SDT) failures were detected, including:

[0317] A small data transfer (SDT) was not completed successfully or a small data transfer was completed but not successfully transferred.

[0318] 2. The method as described in Note 1, wherein:

[0319] The first condition includes:

[0320] The terminal device performs cell reselection while a terminal terminated small data transfer (MT-SDT) process is being performed via a configuration grant (CG); and / or

[0321] The first timer or the second timer times out before the lower layer indication of the terminal device receives the response of the network device to the small data transmission (UL CG-SDT) with uplink configuration authorization carrying the common control channel (CCCH) message, and the small data transmission (MT-SDT) process terminated by the terminal is in progress.

[0322] 3. The method as described in Note 1, wherein:

[0323] The second condition includes:

[0324] Receiving an indication from a Master Cell Group Radio Link Control (MCG RLC) that a maximum number of retransmissions has been reached while a Small Data Transfer (MO-SDT) procedure toward the terminal is in progress; and / or

[0325] A random access problem indication of a master cell group medium access control (MCG MAC) is received while a MO-SDT procedure of the terminal is in progress.

[0326] 4. The method as described in Note 1, wherein:

[0327] No small data transfer (SDT) failures were detected, including:

[0328] The terminal device initiates a random access process.

[0329] 5. The method as described in Note 4, wherein:

[0330] The terminal device initiates a random access process, including:

[0331] Obtaining a Media Access Control Protocol Data Unit (MAC PDU) from an Automatic Repeat Request Buffer (HARQ buffer); and / or

[0332] The acquired media access control protocol data unit (MAC PDU) is placed into the Msg3 buffer or the MsgA buffer.

[0333] 6. The method as described in Supplementary Note 1, wherein the method further comprises:

[0334] When it is determined that a small data transmission (SDT) failure is detected, the terminal device maintains a radio resource control inactive (RRC_INACTIVE) state or enters a radio resource control idle (RRC_IDLE) state.

[0335] 7. The method as described in Supplementary Note 6, wherein:

[0336] When the small data transmission (SDT) is a terminal-oriented small data transmission (MO-SDT), the terminal device enters a radio resource control idle (RRC_IDLE) state; or

[0337] When the small data transmission (SDT) is a terminal terminated small data transmission (MT-SDT), the terminal device remains in a radio resource control inactive (RRC_INACTIVE) state.

[0338] 13. The method as described in Supplement 1, wherein the method further comprises:

[0339] When a small data transmission (SDT) failure is detected for a terminal terminated small data transmission (MT-SDT), a radio resource control establishment (RRC setup) process is initiated.

[0340] 9. The method as described in Note 13, wherein:

[0341] Initiate the radio resource control (RRC setup) process, including:

[0342] The radio resource control (RRC setup) process is initiated by the radio resource control (RRC) layer of the terminal device; or

[0343] The failure is indicated by a radio resource control (RRC) layer of the terminal device to a non-access stratum (NAS).

[0344] 10. The method as described in Supplementary Note 9, wherein:

[0345] The radio resource control (RRC setup) process is initiated by the radio resource control (RRC) layer of the terminal device, including:

[0346] When a small data transmission (SDT) failure is detected for a terminal terminated small data transmission (MT-SDT), the terminal device enters a radio resource control idle (RRC_IDLE) state and initiates the radio resource control establishment (RRC setup) process.

[0347] 11. The method as described in Supplementary Note 10, wherein:

[0348] The cause of initiating the radio resource control setup (RRC setup) procedure is a terminal terminated access (MT-access).

[0349] 12. The method as described in Supplementary Note 9, wherein:

[0350] The radio resource control (RRC) layer of the terminal device indicates the failure to a non-access stratum (NAS), including:

[0351] When a small data transmission (SDT) failure is detected for a terminal terminated small data transmission (MT-SDT), the terminal device enters a radio resource control idle (RRC_IDLE) state, wherein the release reason is the small data transmission (SDT) failure.

[0352] 13. The method as described in Supplementary Note 9, wherein:

[0353] The initiating radio resource control establishment (RRC setup) process further includes:

[0354] Based on the indication, the non-access stratum (NAS) instructs the AS to initiate the radio resource control establishment (RRC setup) process.

[0355] The terminal side method of the second aspect embodiment:

[0356] 1. A method for processing a small data transmission failure, applied to a terminal device, comprising:

[0357] When the small data transmission (SDT) fails, the terminal device maintains a radio resource control inactive (RRC_INACTIVE) state or enters a radio resource control idle (RRC_IDLE) state.

[0358] 2. The method as described in Note 1, wherein:

[0359] When the small data transmission (SDT) is a terminal-oriented small data transmission (MO-SDT), the terminal device enters a radio resource control idle (RRC_IDLE) state; or

[0360] When the small data transmission (SDT) is a terminal terminated small data transmission (MT-SDT), the terminal device remains in a radio resource control inactive (RRC_INACTIVE) state.

[0361] The terminal side method of the third aspect embodiment:

[0362] 1. A method for processing a small data transmission failure, applied to a terminal device, comprising:

[0363] When a small data transmission (SDT) failure is detected for a terminal terminated small data transmission (MT-SDT), a radio resource control establishment (RRC setup) process is initiated.

[0364] 2. The method as described in Note 1, wherein:

[0365] Initiate the radio resource control (RRC setup) process, including:

[0366] The radio resource control (RRC setup) process is initiated by the radio resource control (RRC) layer of the terminal device; or

[0367] The failure is indicated by a radio resource control (RRC) layer of the terminal device to a non-access stratum (NAS).

[0368] 3. The method as described in Note 2, wherein:

[0369] The radio resource control (RRC setup) process is initiated by the radio resource control (RRC) layer of the terminal device, including:

[0370] When a small data transmission (SDT) failure is detected for a terminal terminated small data transmission (MT-SDT), the terminal device enters a radio resource control idle (RRC_IDLE) state and initiates the radio resource control establishment (RRC setup) process.

[0371] 4. The method as described in Note 3, wherein:

[0372] The cause of initiating the radio resource control setup (RRC setup) procedure is a terminal terminated access (MT-access).

[0373] 5. The method as described in Note 2, wherein:

[0374] The indicating, by a radio resource control (RRC) layer of the terminal device, to a non-access stratum (NAS) of the failure, includes:

[0375] When a small data transmission (SDT) failure is detected for a terminal terminated small data transmission (MT-SDT), the terminal device enters a radio resource control idle (RRC_IDLE) state, wherein the release reason is the small data transmission (SDT) failure.

[0376] 6. The method as described in Note 2, wherein:

[0377] The process of initiating the radio resource control establishment (RRC setup) also includes:

[0378] Based on the indication, the non-access stratum (NAS) initiates the radio resource control establishment (RRC setup) process.

[0379] The terminal side method of the fourth aspect embodiment:

[0380] 1. A method for processing small data transmission, applied to a terminal device, comprising:

[0381] When signaling radio bearer 1 (SRB1) is configured with small data transmission (SDT) and / or any data radio bearer (DRB) is not configured with small data transmission (SDT), a downlink (DL) message sent by a network device and the downlink (DL) data carried in the downlink (DL) message are received.

[0382] 1a. The method as described in Note 1, wherein:

[0383] In the absence of any uplink available data, the downlink (DL) message sent by the network device and the downlink (DL) data carried in the downlink (DL) message are received.

[0384] 2. The method as described in Note 1, wherein the method further comprises:

[0385] In a case where the network device resumes a suspended radio resource control (RRC) connection and causes the terminal device to enter a radio resource control connected (RRC_CONNECTED) state, the terminal device performs at least one of the following operations:

[0386] Stop the running timer T319a; and

[0387] If predetermined parameters are configured, instruct the media access control (MAC) entity to: stop the time alignment (TA) timer of the configured authorization-based small data transmission (CG-SDT) that is running, or start the time alignment (TA) timer associated with the primary timing advance group (PTAG) that is not running.

[0388] 3. The method as described in Note 1, wherein the method further comprises:

[0389] Upon receiving an indication from the network device to initiate non-access stratum (NAS) level recovery, the terminal device performs at least one of the following operations:

[0390] If the predetermined parameters are configured, instructing the medium access control (MAC) entity to: stop the time alignment (TA) timer of the configuration grant-based small data transmission (CG-SDT) that is running, or start the time alignment (TA) timer associated with the primary timing advance group (PTAG) that is not running; and

[0391] Stop the running timer T319a.

[0392] 4. The method as described in Note 1, wherein the method further comprises:

[0393] The radio resource control (RRC) connection is released and the terminal device enters a radio resource control idle (RRC_IDLE) state, and the terminal device performs the following operations:

[0394] Stop the running timer T319a.

[0395] 5. The method as described in Note 1, wherein the method further comprises:

[0396] When the terminal device receives a radio resource control release (RRCRelease) message including a suspend configuration (suspendConfig), if small data transmission (SDT) is configured, the terminal device performs at least one of the following operations:

[0397] For each data radio bearer (DRB) in the small data transmission data radio bearer (SDT DRB) list, the terminal device considers that the data radio bearer (DRB) is configured with small data transmission (SDT);

[0398] If a small data transmission signaling radio bearer 2 (SDT SRB2) indication is configured, the terminal device considers that the signaling radio bearer 2 (SRB2) is configured with small data transmission (SDT);

[0399] For at least one unsuspended radio link control (RLC) bearer, the terminal device re-establishes a radio link control (RLC) entity;

[0400] For the restored signaling radio bearer 2 (SRB2) and signaling radio bearer 1 (SRB1), the terminal device triggers a packet data convergence protocol (PDCP) entity to perform service data unit (SDU) discard;

[0401] If the predetermined parameters are configured, the terminal device configures a configuration grant (CG) resource of the small data transmission (SDT) for the primary cell (PCell), and instructs a medium access control (MAC) entity to start a TA timer of the configuration grant small data transmission (CG SDT); and

[0402] Stop the running timer T319a.

[0403] 6. The method as described in Note 1, wherein the method further comprises:

[0404] Upon receiving a radio resource control reject (RRCReject) message for rejecting a resume request of a small data transfer (SDT) process, the terminal device performs at least one of the following operations:

[0405] Stop the running timer T319a;

[0406] For the restored signaling radio bearer 2 (SRB2) and signaling radio bearer 1 (SRB1), the terminal device triggers a packet data convergence protocol (PDCP) entity to discard a service data unit (SDU) and re-establish a radio link control (RLC) entity;

[0407] For at least one unsuspended data radio bearer (DRB), the terminal device instructs a packet data convergence protocol (PDCP) to suspend a lower layer and re-establish a radio link control (RLC) entity; and

[0408] Suspend Signalling Radio Bearer 1 (SRB1) and radio bearers configured with Small Data Transport (SDT).

[0409] The network side method of the fifth aspect embodiment:

[0410] 1. A method for processing small data transmission, applied to a network device, comprising:

[0411] When signaling radio bearer 1 (SRB1) is configured with small data transmission (SDT) and / or any data radio bearer (DRB) is not configured with small data transmission (SDT), downlink (DL) data is carried in a downlink (DL) message.

[0412] 1a. The method as described in Note 1, wherein:

[0413] In the absence of any uplink available data, the downlink (DL) data is carried in the downlink (DL) message.

[0414] 2. The method as described in Note 1, wherein:

[0415] The downlink (DL) message is used to resume a suspended radio resource control (RRC) connection and enable the terminal device to enter a radio resource control connected (RRC_CONNECTED) state; or

[0416] The downlink (DL) message is used to instruct the terminal device to initiate non-access stratum (NAS) level recovery; or

[0417] The downlink (DL) message is used to release the radio resource control (RRC) connection and enable the terminal device to enter a radio resource control idle (RRC_IDLE) state; or

[0418] The downlink (DL) message is used to re-suspend the radio resource control (RRC) connection and cause the terminal device to enter a radio resource control inactive (RRC_INACTIVE) state; or

[0419] The downlink (DL) message is used to reject the resumption request of the small data transmission (SDT) process and enable the terminal device to enter the radio resource control inactive (RRC_INACTIVE) state.

Claims

1. A device for processing a small data transmission failure, applied to a terminal device, the device comprising a first processing unit, the first processing unit controlling the terminal device to enable the terminal device to perform the following operations: When the first condition is met, for a terminal terminated small data transmission (MT-SDT), it is determined that no small data transmission (SDT) failure is detected; and / or, When the second condition is satisfied, for the terminal-oriented small data transmission (MO-SDT), it is determined that a small data transmission (SDT) failure is detected.

2. The device according to claim 1, wherein: No small data transfer (SDT) failures were detected, including: The small data transfer (SDT) is not completed, the small data transfer (SDT) is completed, or the small data transfer (SDT) is successfully completed.

3. The device according to claim 1, wherein: Small Data Transfer (SDT) failures were detected, including: A small data transfer (SDT) was not completed successfully or a small data transfer was completed but not successfully transferred.

4. The device according to claim 1, wherein: The first condition includes: The terminal device performs cell reselection while the terminal terminated small data transmission (MT-SDT) process is being performed through a configuration grant (CG); and / or The first timer or the second timer times out before the low layer indication of the terminal device receives a response from the network device to the small data transmission (UL CG-SDT) with uplink configuration authorization carrying the common control channel (CCCH) message, and the small data transmission (MT-SDT) process terminated by the terminal is in progress.

5. The device according to claim 1, wherein: The second condition includes: Receiving an indication from a master cell group radio link control (MCG RLC) that a maximum number of retransmissions has been reached while a MO-SDT procedure is in progress; and / or A random access problem indication of a master cell group medium access control (MCG MAC) is received while a MO-SDT procedure of the terminal is in progress.

6. The device according to claim 1, wherein: No small data transfer (SDT) failures were detected, including: The terminal device initiates a random access process.

7. The device according to claim 6, wherein: The terminal device initiates a random access process, including: Obtaining a media access control protocol data unit (MAC PDU) from an automatic repeat request buffer (HARQ buffer); and / or The acquired media access control protocol data unit (MAC PDU) is placed into the Msg3 buffer or the MsgA buffer.

8. The device of claim 1, wherein: This operation also includes: When it is determined that a small data transmission (SDT) failure is detected, the terminal device maintains a radio resource control inactive (RRC_INACTIVE) state or enters a radio resource control idle (RRC_IDLE) state.

9. The device of claim 8, wherein: When the small data transmission (SDT) is a terminal-oriented small data transmission (MO-SDT), the terminal device enters a radio resource control idle (RRC_IDLE) state; or When the small data transmission (SDT) is a terminal terminated small data transmission (MT-SDT), the terminal device remains in a radio resource control inactive (RRC_INACTIVE) state.

10. The device of claim 1, wherein: This operation also includes: When a small data transmission (SDT) failure is detected for a terminal terminated small data transmission (MT-SDT), a radio resource control establishment (RRC setup) procedure is initiated.

11. The device of claim 10, wherein: Initiate the radio resource control establishment (RRC setup) process, including: The radio resource control (RRC setup) process is initiated by the radio resource control (RRC) layer of the terminal device; or The failure is indicated by a radio resource control (RRC) layer of the terminal device to a non-access stratum (NAS).

12. The device of claim 11, wherein: The radio resource control (RRC) layer of the terminal device indicates the failure to a non-access stratum (NAS), including: When a small data transfer (SDT) failure is detected for a terminal terminated small data transfer (MT-SDT), the The terminal device enters a radio resource control idle (RRC_IDLE) state, wherein the release reason is a small data transmission (SDT) failure.

13. A device for processing a small data transmission failure, applied to a terminal device, the device comprising a third processing unit, the third processing unit controlling the terminal device to enable the terminal device to perform the following operations: When a small data transmission (SDT) failure is detected for a terminal terminated small data transmission (MT-SDT), a radio resource control establishment (RRC setup) procedure is initiated.

14. The device of claim 13, wherein: Initiate the radio resource control establishment (RRC setup) process, including: The radio resource control (RRC setup) process is initiated by the radio resource control (RRC) layer of the terminal device; or The failure is indicated by a radio resource control (RRC) layer of the terminal device to a non-access stratum (NAS).

15. The device of claim 14, wherein: The radio resource control (RRC setup) process is initiated by the radio resource control (RRC) layer of the terminal device, including: When a small data transmission (SDT) failure is detected for a terminal terminated small data transmission (MT-SDT), the terminal device enters a radio resource control idle (RRC_IDLE) state and initiates the radio resource control establishment (RRC setup) process.

16. The device of claim 14, wherein: The indicating, by a radio resource control (RRC) layer of the terminal device, to a non-access stratum (NAS) of the failure, comprises: When a small data transmission (SDT) failure is detected for a terminal terminated small data transmission (MT-SDT), the terminal device enters a radio resource control idle (RRC_IDLE) state, wherein the release reason is the small data transmission (SDT) failure.

17. The device of claim 14, wherein: The process of initiating the radio resource control establishment (RRC setup) also includes: Based on the indication, the non-access stratum (NAS) initiates the radio resource control establishment (RRC setup) process.

18. A small data transmission processing device, applied to a network device, the device comprising a fifth processing unit, the fifth processing unit controlling the network device to enable the network device to perform the following operations: When signaling radio bearer 1 (SRB1) is configured with small data transmission (SDT) and / or any data radio bearer (DRB) is not configured with small data transmission (SDT), downlink (DL) data is carried in a downlink (DL) message.

19. The device of claim 18, wherein: In the case of no uplink available data, the downlink (DL) data is carried in the downlink (DL) message.

20. The apparatus of claim 18, wherein: The downlink (DL) message is used to resume a suspended radio resource control (RRC) connection and enable the terminal device to enter a radio resource control connected (RRC_CONNECTED) state; or The downlink (DL) message is used to instruct the terminal device to initiate non-access stratum (NAS) level recovery; or The downlink (DL) message is used to release the radio resource control (RRC) connection and enable the terminal device to enter a radio resource control idle (RRC_IDLE) state; or The downlink (DL) message is used to re-suspend the radio resource control (RRC) connection and cause the terminal device to enter a radio resource control inactive (RRC_INACTIVE) state; or The downlink (DL) message is used to reject the resumption request of the small data transmission (SDT) process and make the terminal device enter the radio resource control inactive (RRC_INACTIVE) state.

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