Timer control for congestion handling
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2026-01-28
- Publication Date
- 2026-08-13
Smart Images
Figure EP2026052192_13082026_PF_FP_ABST
Abstract
Description
TIMER CONTROL FOR CONGESTION HANDLING FIELD
[0001] Various example embodiments relate to the field of communication and in particular, to devices, methods, apparatuses and a computer readable storage medium for timer control for congestion handling.BACKGROUND
[0002] A communication network may be seen as a facility that enables communications between two or more communication devices, or provides communication devices access to a data network. A mobile or wireless communication network is one example of a communication network.
[0003] Such communication networks operate in accordance with standards, such as those promulgated by 3GPP (Third Generation Partnership Project) or ETSI (European Telecommunications Standards Institute). Examples of such standards include the so-called 5G (5th Generation) standard, 6G (6th Generation) standard or other standards promulgated by 3 GPP.SUMMARY
[0004] In general, example embodiments of the present disclosure provide methods and apparatuses related to timer control for congestion handing for an uplink NAS transport session, especially for backoff timer control at a source terminal for congestion handling.
[0005] In a first aspect, there is provided a terminal device. The terminal device comprises at least one processor and at least one memory storing instructions. The instructions, when executed by the at least one processor, cause the terminal device at least to receive, at a first sublayer of the terminal device, a first message comprising first data, an identity (ID) of a session, a cause value and a timer value; transmit, from the first sublayer of the terminal device to a second sublayer of the terminal device, the first data, the ID of the session, an indication and the timer value, wherein the indication is based on the cause value and indicates congestion in at least one of a data network identified by a data network name (DNN) or a network slice identified by a single network slice selection assistance information (S-NSSAI); and perform at least one action for at least one backoff timer basedon the indication, the timer value and the ID of the session.
[0006] In some embodiments, the timer value does not indicate that the timer is deactivated. The terminal device is caused to perform the at least one action by at least one of: stopping the at least one backoff timer; or if the timer value does not indicate zero, starting the at least one backoff timer with the timer value.
[0007] In some embodiments, the terminal device is further caused to receive, at the first sublayer, a second message which comprises second data and the ID of the session and is without any cause value; receive, at the second sublayer from the first sublayer, the second data and the ID of the session; and based on that the at least one backoff timer is running, stop the at least one backoff timer based on the reception of the second data and the ID of the session.
[0008] In some embodiments, the indication indicates the congestion is in the data network identified by the DNN. The terminal device provided the DNN during establishment of the session. The terminal device is caused to stop the at least one backoff timer by: stopping a first timer associated with the DNN in the at least one backoff timer, and wherein if the timer value does not indicate zero, the terminal device is caused to start the at least one backoff timer with the timer value by: starting the first timer associated with the DNN with the timer value.
[0009] In some embodiments, the indication indicates the congestion is in the data network identified by the DNN. The terminal device did not provide any DNN during establishment of the session. The terminal device is caused to stop the at least one backoff timer by: stopping a first timer associated with no DNN in the at least one backoff timer, and wherein if the timer value does not indicate zero, the terminal device is caused to start the at least one backoff timer with the timer value by: starting the first timer associated with no DNN with the timer value.
[0010] In some embodiments, the terminal device is further caused to: keep the first timer running based on a public land mobile network (PLMN) change or an inter-system change.
[0011] In some embodiments, the first timer comprises a timer T3396.
[0012] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN. The terminal device provided the DNN and the S-NSSAI during establishment of the session, the terminal deviceis caused to stop the at least one backoff timer by: stopping a second timer associated with the DNN and the S-NSSAI in the at least one backoff timer, and wherein if the timer value does not indicate zero, the terminal device is caused to start the at least one backoff timer with the timer value by: starting the second timer associated with the DNN and the S-NSSAI with the timer value.
[0013] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN. The terminal device provided the DNN and did not provide any S-NSSAI during establishment of the session. The terminal device is caused to stop the at least one backoff timer by: stopping a second timer associated with the DNN and no S-NSSAI in the at least one backoff timer, and wherein if the timer value does not indicate zero, the terminal device is caused to start the at least one backoff timer with the timer value by: starting the second timer associated with the DNN and no S-NSSAI with the timer value.
[0014] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN. The terminal device provided the S-NSSAI and did not provide any DNN during establishment of the session, the terminal device is caused to stop the at least one backoff timer by: stopping a second timer associated with the S-NSSAI and no DNN in the at least one backoff timer, and wherein if the timer value does not indicate zero, the terminal device is caused to start the at least one backoff timer with the timer value by: starting the second timer associated with the S-NSSAI and no DNN with the timer value.
[0015] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN. The terminal device did not provide any DNN or any S-NSSAI during establishment of the session. The terminal device is caused to stop the at least one backoff timer by: stopping a second timer associated with no S-NSSAI and no DNN in the at least one backoff timer, and wherein if the timer value does not indicate zero, the terminal device is caused to start the at least one backoff timer with the timer value by: starting the second timer associated with no DNN and no S-NSSAI with the timer value.
[0016] In some embodiments, the second timer comprises a timer T3584.
[0017] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI. The terminal device provided the S-NSSAI during establishmentof the session. The terminal device is caused to stop the at least one backoff timer by: stopping a third timer associated with the S-NSSAI in at least one backoff timer, and wherein if the timer value does not indicate zero, the terminal device is caused to start the at least one backoff timer with the timer value by: starting the third timer associated with the S-NSSAI with the timer value.
[0018] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI. The terminal device did not provide any S-NSSAI during establishment of the session. The terminal device is caused to stop the at least one backoff timer by: stopping a third timer associated with no S-NSSAI in the at least one backoff timer, and wherein if the timer value does not indicate zero, the terminal device is caused to start the at least one backoff timer with the timer value by: starting the third timer associated with no S-NSSAI with the timer value.
[0019] In some embodiments, the terminal device is further caused to: keep the third timer running in case of a PLMN change or an inter-system change.
[0020] In some embodiments, the third timer comprises a timer T3585.
[0021] In some embodiments, the timer value indicates the timer is deactivated. The terminal device is caused to perform the at least one action by: stopping the at least one backoff timer; and keeping the at least one backoff timer as deactivated.
[0022] In some embodiments, the indication indicates the congestion is in the data network identified by the DNN. The terminal device provided the DNN during establishment of the session. The terminal device is caused to stop the at least one backoff timer by: stopping a first timer associated with the DNN in the at least one backoff timer, and wherein the terminal device is caused to keep the at least one backoff timer as deactivated by: keeping the first timer associated with the DNN as deactivated.
[0023] In some embodiments, the indication indicates the congestion is in the data network identified by the DNN. The terminal device did not provide any DNN during establishment of the session. The terminal device is caused to stop the at least one backoff timer by: stopping a first timer associated with no DNN in the at least one backoff timer, and wherein the terminal device is caused to keep the at least one backoff timer as deactivated by: keeping the first timer associated with no DNN as deactivated.
[0024] In some embodiments, the terminal device is further caused to: keep the first timeras deactivated in case of a PLMN change or an inter-system change.
[0025] In some embodiments, the first timer comprises a timer T3396.
[0026] In some embodiments, the indication indicates the congestion is in the data network identified by the DNN and the network slice identified by the S-NSSAI. The terminal device provided the DNN and the S-NSSAI during establishment of the session. The terminal device is caused to stop the at least one backoff timer by: stopping a second timer associated with the DNN and the S-NSSAI in the at least one backoff timer, and wherein the terminal device is caused to keep the at least one backoff timer as deactivated by: keeping the second timer associated with the DNN and the S-NSSAI as deactivated.
[0027] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN. The terminal device provided the DNN and did not provide any S-NSSAI during establishment of the session. The terminal device is caused to stop the at least one backoff timer by: stopping a second timer associated with the DNN and no S-NSSAI in the at least one backoff timer, and wherein the terminal device is caused to keep the at least one backoff timer as deactivated by: keeping the second timer associated with the DNN and no S-NSSAI as deactivated.
[0028] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN. The terminal device did not provide any DNN and provided S-NSSAI during establishment of the session. The terminal device is caused to stop the at least one backoff timer by: stopping a second timer associated with S-NSSAI and no DNN in the at least one backoff timer, and wherein the terminal device is caused to keep the at least one backoff timer as deactivated by: keeping the second timer associated with the S-NSSAI and no DNN as deactivated.
[0029] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN. The terminal device did not provide any DNN or any S-NSSAI during establishment of the session. The terminal device is caused to stop the at least one backoff timer by: stopping a second timer associated with no S-NSSAI and no DNN in the at least one backoff timer, and wherein the terminal device is caused to keep the at least one backoff timer as deactivated by: keeping the second timer associated with no DNN and no S-NSSAI as deactivated.
[0030] In some embodiments, the terminal device is further caused to: keep the second timer as deactivated in case of a PLMN change or an inter-system change.
[0031] In some embodiments, the second timer comprises a timer T3584.
[0032] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI. The terminal device provided the S-NSSAI during establishment of the session. The terminal device is caused to stop the at least one backoff timer by: stopping a third timer associated with the S-NSSAI in at least one backoff timer, and wherein the terminal device is caused to keep the at least one backoff timer as deactivated by: keeping the third timer associated with the S-NSSAI as deactivated.
[0033] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI. The terminal device did not provide any S-NSSAI during establishment of the session. The terminal device is caused to stop the at least one backoff timer by: stopping a third timer associated with no S-NSSAI in the at least one backoff timer, and wherein the terminal device is caused to keep the at least one backoff timer as deactivated by: keeping the third timer associated with no S-NSSAI as deactivated.
[0034] In some embodiments, the terminal device is further caused to: keep the third timer as deactivated in case of a PLMN change or an inter-system change.
[0035] In some embodiments, at least one of: the third timer is applied for a plurality of PLMNs and for a 3GPP access type; the third timer is applied for the plurality of PLMNs and for both the 3GPP access type and a non-3GPP access type; the third timer is applied for a registered PLMN of the plurality of PLMNs and for the 3GPP access type; or the third timer is applied for the registered PLMN of the plurality of PLMNs and for the 3GPP access type and the non-3GPP access type.
[0036] In some embodiments, the third timer comprises a timer T3585.
[0037] In some embodiments, the terminal device is further caused to: based on determining that the terminal device is switched off when the at least one backoff timer is running and a USIM in the terminal device is unchanged, set tl be time remaining for timer timeout at switch off and t be time elapsed between switch off and switch on; and based on determining that the tl is greater than t, restart the at least one backoff timer with a value of tl minus t; based on determining that tl is equal to or less than t, avoid the at least one backoff timer to be restarted; or based on determining that the terminal device is not capable of determining t, restart the at least one backoff timer with the value tl .
[0038] In some embodiments, at least one of: the first sublayer comprises a mobilitymanagement (MM) sublayer; the second sublayer comprises a session management (SM) sublayer; the first data comprises first cellular Internet-of-Things (CIoT) user data; the second data comprises second CIoT user data; the session comprises a protocol data unit (PDU) session; and the cause value comprises an MM cause value.
[0039] In a second aspect, there is provided a method. The method comprises receiving, at a first sublayer of the terminal device, a first message comprising first data, an ID of a session, a cause value and a timer value; transmitting, from the first sublayer of the terminal device to a second sublayer of the terminal device, the first data, the ID of the session, an indication and the timer value, wherein the indication is based on the cause value and indicates congestion in at least one of a data network identified by a DNN or a network slice identified by S-NSSAI; and performing at least one action for at least one backoff timer based on the indication, the timer value and the ID of the session.
[0040] In a third aspect, there is provided an apparatus. The apparatus comprises means for receiving, at a first sublayer of the terminal device, a first message comprising first data, an ID of a session, a cause value and a timer value; means for transmitting, from the first sublayer of the terminal device to a second sublayer of the terminal device, the first data, the ID of the session, an indication and the timer value, wherein the indication is based on the cause value and indicates congestion in at least one of a data network identified by a DNN or a network slice identified by S-NSSAI; and means for performing at least one action for at least one backoff timer based on the indication, the timer value and the ID of the session.
[0041] In a fourth aspect, there is provided a non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the method according to second aspect.
[0042] In a fifth aspect, there is provided a computer program comprising instructions, which, when executed by an apparatus, cause the apparatus to perform at least the method according to second aspect.
[0043] In a sixth aspect, there is provided an apparatus. The apparatus comprises receiving circuitry configured to receive, at a first sublayer of the terminal device, a first message comprising first data, an ID of a session, a cause value and a timer value; transmitting circuitry configured to transmit, from the first sublayer of the terminal device to a second sublayer of the terminal device, the first data, the ID of the session, an indication and the timer value, wherein the indication is based on the cause value and indicates congestion inat least one of a data network identified by a DNN or a network slice identified by S-NSSAI; and performing circuitry configured to perform at least one action for at least one backoff timer based on the indication, the timer value and the ID of the session.
[0044] It is to be understood that the summary section is not intended to identify key or essential features of embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become easily comprehensible through the following description.BRIEF DESCRIPTION OF THE DRAWINGS
[0045] Some example embodiments will now be described with reference to the accompanying drawings, in which:
[0046] FIG. 1 A illustrates an example communication network in which embodiments of the present disclosure may be implemented;
[0047] FIG. IB illustrates a signaling diagram illustrating an example of process for congestion control;
[0048] FIG. 1C illustrates a signaling diagram illustrating an example of process for congestion control;
[0049] FIG. 2 illustrates a signaling diagram illustrating an example of process for timer control for congestion handling according to some embodiments of the present disclosure;
[0050] FIG. 3 illustrates a signaling diagram illustrating an example of another process for timer control for congestion handling according to some embodiments of the present disclosure;
[0051] FIG. 4 illustrates a signaling diagram illustrating an example of process for timer control for congestion handling according to some embodiments of the present disclosure;
[0052] FIG. 5 illustrates a flowchart of a method implemented at a terminal device according to some embodiments of the present disclosure;
[0053] FIG. 6 illustrates a flowchart of a method implemented at a terminal device according to some embodiments of the present disclosure;
[0054] FIG. 7 illustrates a simplified block diagram of an apparatus that is suitable for implementing embodiments of the present disclosure; and
[0055] FIG. 8 illustrates a block diagram of an example computer readable medium in accordance with some embodiments of the present disclosure.
[0056] Throughout the drawings, the same or similar reference numerals represent the same or similar element.DETAILED DESCRIPTION
[0057] Principles of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. The disclosure described herein may be implemented in various manners other than the ones described below.
[0058] In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which this disclosure belongs.
[0059] References in the present disclosure to “one embodiment,” “an embodiment,” “an example embodiment,” and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.
[0060] It shall be understood that although the terms “first” and “second” etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and / or” includes any and all combinations of one or more of the listed terms.
[0061] The terminology used herein is for describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms “comprises”, “comprising”, “has”, “having”, “includes” and / or “including”, when used herein, specify the presence of stated features, elements, and / or components etc., but do not preclude the presence or addition of one or more other features, elements, components and / or combinations thereof. As used herein, “at least one of the following: ” and “at least one of ” and similar wording, where the list of two or more elements are joined by “and” or “or”, mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.
[0062] As used in this application, the term “circuitry” may refer to one or more or all of the following:(a) hardware-only circuit implementations (such as implementations in only analog and / or digital circuitry) and(b) combinations of hardware circuits and software, such as (as applicable):(i) a combination of analog and / or digital hardware circuit(s) with software / firmware and(ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and (c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.
[0063] This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.
[0064] As used herein, the term “communication network” refers to a network following any suitable communication standards, such as Long Term Evolution (LTE), LTE- Advanced(LTE-A), Wideband Code Division Multiple Access (WCDMA), High-Speed Packet Access (HSPA), Narrow Band Internet of Things (NB-IoT) and so on. Furthermore, the communications between a terminal device and a network device in the communication network may be performed according to any suitable generation communication protocols, including, but not limited to, the first generation (1G), the second generation (2G), 2.5G, 2.75G, the third generation (3G), the fourth generation (4G), 4.5G, the future fifth generation (5G) and the sixth generation (6G) communication protocols, and / or any other protocols either currently known or to be developed in the future. Embodiments of the present disclosure may be applied in various communication systems. Given the rapid development in communications, there will of course also be future type communication technologies and systems with which the present disclosure may be embodied. It should not be seen as limiting the scope of the present disclosure to only the aforementioned system.
[0065] As used herein, the term “network device” and “core network device” refer to a core network is the central part of a telecommunications network. It serves as the backbone that connects various access networks (such as wireless access networks for mobile devices or wired access networks for fixed - line services) to each other and to external networks like the Internet. In essence, it is responsible for managing and routing data, voice, and other services between different endpoints. The core network is designed to be more flexible, scalable, and service oriented. It features a service based architecture, where network functions like the Access and Mobility Management Function (AMF), Session Management Function (SMF), and Policy Control Function (PCF) communicate with each other through well-defined service based interfaces. The 5G core network aims to support a wide range of new services, including massive machine type communication (mMTC) for the Internet of Things (loT), ultra-reliable low latency communication (URLLC) for applications like autonomous driving, and enhanced mobile broadband (eMBB) for high definition video streaming and other high data rate services.
[0066] The term “terminal device” refers to any end device that may be capable of wireless communication. By way of example rather than limitation, a terminal device may also be referred to as a communication device, user equipment (UE), a Subscriber Station (SS), a Portable Subscriber Station, a Mobile Station (MS), or an Access Terminal (AT). The terminal device may include, but not limited to, a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones, a tablet, a wearable terminal device, a personal digital assistant (PDA), portable computers, desktop computer, imagecapture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), USB dongles, smart devices, wireless customer-premises equipment (CPE), an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and / or other wireless devices operating in an industrial and / or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and / or industrial wireless networks, and the like. In the following description, the terms “terminal device”, “communication device”, “terminal”, “user equipment” and “UE” may be used interchangeably.
[0067] FIG. 1 A illustrates an example communication network in which embodiments of the present disclosure may be implemented.
[0068] As shown in FIG. 1A, the communication network 100 A may include a terminal device 110, a mobility management (MM) NF 120 and a session management (SM) NF 130 comprised in a core network 140. The terminal device 110 comprises an SM sublayer 110-1 and MM sublayer 110-2. The SM sublayer 110-1 may be the 5G SM sublayer and / or SM (sublayer) entity. The MM sublayer 110-2 may be the 5G MM sublayer and / or MM (sublayer) entity. The MM NF 120 may be the AMF in the 5G system (5GS) and the SM NF 130 may be the SMF in the 5GS.
[0069] It is to be understood that the number of terminal devices, the SM sublayers and the MM sublayers is only for the purpose of illustration without suggesting any limitations. The system 100 A may include any suitable number of terminal devices the SM sublayers and the MM sublayers adapted for implementing embodiments of the present disclosure.
[0070] Communications in the communication system 100 A may be implemented according to any proper communication protocol(s), comprising, but not limited to, cellular communication protocols of the first generation (1G), the second generation (2G), the third generation (3G), the fourth generation (4G), the fifth generation (5G) and the sixth generation (6G) and on the like, wireless local network communication protocols such as Institute for Electrical and Electronics Engineers (IEEE) 802.11 and the like, and / or any other protocols currently known or to be developed in the future. Moreover, the communication may utilize any proper wireless communication technology, comprising butnot limited to: Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Frequency Division Duplex (FDD), Time Division Duplex (TDD), Multiple-Input Multiple-Output (MIMO), Orthogonal Frequency Division Multiple (OFDM), Discrete Fourier Transform spread OFDM (DFT-s-OFDM) and / or any other technologies currently known or to be developed in the future.
[0071] As an example, when resources in a mobile communication network (communication system 100A) for a specific data network (identified by a DNN) and / or a specific network slice (identified by an S-NSSAI) are insufficient, an entity in the mobile communication network can perform DNN-based congestion control and / or S-NSSAI-based congestion control.
[0072] FIG. IB illustrates a signaling diagram illustrating an example of process 100B for congestion control. For the purpose of discussion, the process 100B will be described with reference to FIG. 1 A. The process 100B may involve the terminal device 110, MM NF 120 and SM NF 130. The terminal device 110 comprises the SM sublayer 110-1 and MM sublayer 110-2 as illustrated in FIG. 1A.
[0073] Step IB, the SM sublayer 110-1 in the terminal device 110 may construct an SM message for a session.
[0074] Step 2B, the SM sublayer 110-1 may send the SM message for the session to another sublayer in the terminal device 110, MM sublayer 110-2. In addition to the SM message, the SM sublayer 110-1 may provide the MM sublayer 110-2 with an identifier or identity for the session (session ID).
[0075] Step 3B, The MM sublayer 110-2 may create a UL NAS TRANSPORT message. The UL NAS TRANSPORT message includes the SM message and the session ID. The MM sublayer 110-2 may send the UL NAS TRANSPORT message to an MM NF 120 in the mobile communication network (communication network system 100 A illustrated in FIG.1A).
[0076] Step 4B, upon receiving the UL NAS TRANSPORT message, the MM NF 120 may forward the SM message to an SM NF 130 which is serving or is to serve the session identified by the session ID.
[0077] Step 5B, the SM NF 130 may determine that there is congestion in a data network identified by a DNN and / or in a network slice identified by an S-NSSAI. The DNN and theS-NSSAI are associated with the session identified by the session ID.
[0078] Step 6B, as a response to the SM message originated from the 5G SM sublayer 110-1 in the terminal device 110, the SM NF 130 may create an SM message. The created SM message includes an SM cause value and a timer value. The SM NF 130 may invoke an MM NF service and sends a request to the MM NF 120. The request includes the created SM message and the session ID.
[0079] Step 7B, in order to forward the SM message received from the SM NF 130, the MM NF 120 may create a DL NAS TRANSPORT message, includes the SM message, together with the session ID, in the DL NAS TRANSPORT message, and send the DL NAS TRANSPORT message to the terminal device 110.
[0080] Step 8B, The MM sublayer 110-2 in the terminal device 110 may forward the SM message and the session ID to the SM sublayer 110-1.
[0081] Step 9B, the SM sublayer 110-1 may start a timer whose value is set according to the timer value included in the SM message. The timer is associated with the DNN, the S-NSSAI, or both. Whether the timer is associated with the DNN, the S-NSSAI, or both is determined based on the SM cause value in the SM message. The DNN and the S-NSSAI are determined using the session ID.
[0082] As it can be seen from FIG. IB, it is the SM NF 130 which provides the UE with the timer value and the SM cause value.
[0083] However, in some scenarios, the MM NF (e.g., AMF in case of 5GS) may send a timer value and a cause value (MM cause value, not SM cause value because it is sent by the MM NF) to the terminal device when a CIoT user data container cannot be forwarded from the MM NF to the SM NF (SMF in case of 5GS) due to congestion in a data network or a network slice.
[0084] FIG. 1C illustrates a signaling diagram illustrating an example of process 100C for congestion control. In process 100C, the MM NF 120 sends a timer value and a cause value to the terminal device when a CIoT user data container cannot be forwarded from the MM NF to the SM NF due to congestion in a data network or a network slice. For the purpose of discussion, the process 100C will be described with reference to FIG. 1A. The process 100C may involve the terminal device 110 and the MM NF 120. The terminal device 110 comprises the SM sublayer 110-1 and MM sublayer 110-2 as illustrated in FIG. 1A.
[0085] Step 1C, the SM sublayer 110-1 in the terminal device 110 may identify a need to send user data over control plane (e.g., CIoT user data) for a session.
[0086] Step 2C, the SM sublayer 110-1 may send the user data for the session to another sublayer in the terminal device 110, the MM sublayer 110-2. In addition to the user data, the SM sublayer 110-2 may provide the MM sublayer 110-1 with an identifier or identity for the session (session ID).
[0087] Step 3C, the MM sublayer 110-2 may create an UL NAS TRANSPORT message. The UL NAS TRANSPORT message may include the user data and the session ID. The MM sublayer 110-2 may send the UL NAS TRANSPORT message to the MM NF 120 in the mobile communication network (communication network system 100 A illustrated in FIG.1A).
[0088] Step 4C, the MM NF 120 may determine that there is congestion in a data network identified by a DNN and / or in a network slice identified by an S-NSSAI. The DNN and the S-NSSAI are associated with the session identified by the session ID.
[0089] Step 5C, the MM NF 120 may create a DL NAS TRANSPORT message. The DL NAS TRANSPORT message includes an MM cause value, a timer value, and the session ID. The MM NF 120 may send the DL NAS TRANSPORT message to the terminal device 110.
[0090] Step 6C, the MM sublayer 110-2 in the terminal device 110 may forward the user data and the timer value included in the DL NAS TRANSPORT message to the SM sublayer 110-1.
[0091] In addition, the MM sublayer 110-2 may create an indication from the MM cause value included in the DL NAS TRANSPORT message (e.g., if the MM cause value is the 5GMM cause #22 "Congestion", the 5GMM cause #67 "insufficient resources for specific slice and DNN", or the 5GMM cause #69 "insufficient resources for specific slice", the indication is, respectively, an indication that the CIoT user data was not forwarded due to DNN based congestion control, an indication that the CIoT user data was not forwarded due to S-NSSAI and DNN based congestion control, or an indication that the CIoT user data was not forwarded due to S-NSSAI only based congestion control.
[0092] Based on the process 100C, the following items need to be further discussed:
[0093] - How (the SM sublayer of) the terminal device operates and handle the congestion information, for example, the control for (backoff) timers associated with dataretransmissions; and
[0094] - The process 100C may not be feasible because the session ID is not delivered to the SM sublayer. Without the session ID, the SM sublayer cannot determine the appropriate DNN and / or S-NSSAI for which the congestion control applies.
[0095] In view of the above discussions and analysis, some example embodiments of the present disclosure provide methods and apparatuses related to timer control for congestion handling, especially for controlling a backoff timer for congestion handling. In one aspect of the present disclosure, a terminal device receives, at a first sublayer of the terminal device, a first message comprising first data, an ID of a session, a cause value and a timer value. The terminal device transmits, from the first sublayer of the terminal device to a second sublayer of the terminal device, the first data, the ID of the session, an indication and the timer value. The terminal device performs at least one action for at least one timer based on the indication, the timer value and the ID of the session. In some embodiments, the at least one timer comprises backoff timer(s). For illustration purpose, “backoff timer” is used in the following paragraphs.
[0096] Based on the first aspect of the present disclosure, the terminal device is able to handle notification and message exchange with network, and take appropriate actions for the backoff timer control depending on the message received. In addition, based on the session ID, the SM sublayer may determine the appropriate data network identified by the DNN and / or S-NSSAI for which the congestion control applies. Principles and implementations of example embodiments of the present disclosure will be described in detail below with reference to FIGS. 1A-6.
[0097] FIG. 2 illustrates a signaling diagram illustrating an example of a process 200 for timer control for congestion handling according to some embodiments of the present disclosure. For the purpose of discussion, the process 200 will be described with reference to FIG. 1 A. The process 200 may involve the terminal device 201 comprising SM sublayer 201-1 and MM sublayer 201-2, and MM NF 220. The first sublayer 201-2 may be the MM sublayer 110-2 and the second sublayer 201-1 may be the SM sublayer 110-1 in FIG. 1A. The terminal device 201 may be the terminal device 110 and the MM NF 202 may be the MM NF 120 as illustrated in FIG. 1 A.
[0098] In FIG. 2, at 210, the terminal device 201 receives, at the first sublayer 201-2 of the terminal device 201, a first message comprising first data, an ID of a session, a cause valueand a timer value. This first message may be sent from the MM NF 220.
[0099] In some embodiments, the first data may comprise first CIoT user data, the session may comprise a PDU session and the cause value may comprise an MM cause value.
[0100] At 220, the terminal device 201 may transmit, from the first sublayer 201-2 of the terminal device 201 to a second sublayer 201-1 of the terminal device 201, the first data, the ID of the session, an indication and the timer value. The indication is based on the cause value and indicates congestion in at least one of a data network identified by a data network name (DNN) or a network slice identified by single network slice selection assistance information (S-NSSAI).
[0101] At 230, the terminal device 201 may perform at least one action for at least one backoff timer based on the indication, the timer value and the ID of the session.
[0102] In some embodiments, the timer value does not indicate that the timer is deactivated. The terminal device 201 may stop the at least one backoff timer. Additionally or alternatively, if the timer value does not indicate zero, the terminal device 201 may start the at least one backoff timer with the timer value. In some embodiments, the at least one backoff timer may comprise a first timer (e.g., T3396), a second timer (e.g., T3584), and a third timer (e.g., T3585).
[0103] In some embodiments, the indication indicates the congestion is in the data network identified by the DNN. In the previous session establishment process, the terminal device 201 provided the DNN during establishment of the session, the at least one backoff timer may comprise the first timer (e.g., T3396). The terminal device 201 may stop a first timer associated with the DNN in the at least one backoff timer. Additionally or alternatively, if the timer value does not indicate zero, the terminal device 201 may start the first timer associated with the DNN with / using the timer value.
[0104] Timer value indicating zero or non-zero
[0105] In some embodiments, the indication indicates the congestion is in the data network identified by the DNN. In the previous session establishment process, the terminal device 201 did not provide the DNN during establishment of the session, the at least one backoff timer may comprise the first timer (T3396). The terminal device 201 may stop a first timer associated with no DNN in the at least one backoff timer. Additionally or alternatively, if the timer value does not indicate zero, the terminal device 201 may start the first timer associatedwith no DNN with / using the timer value.
[0106] In some embodiments, the terminal device 201 may keep the first timer running based on a public land mobile network (PLMN) change or an inter-system change.
[0107] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN. In these embodiments, if / when / based on the terminal device 201 provided the DNN and the S-NSSAI during establishment of the session, the at least one backoff timer comprises the second timer (e.g., T3584). The terminal device 201 may stop a second timer associated with the DNN and the S-NSSAI in the at least one backoff timer. Additionally or alternatively, if the timer value does not indicate zero, the terminal device 201 may start the second timer associated with the DNN and the S-NSSAI with / using the timer value.
[0108] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN. In these embodiments, if / when / based on the terminal device 201 provided the DNN and did not provide any S-NSSAI during establishment of the session, the at least one backoff timer comprises the second timer (e.g., T3584). The terminal device 201 may stop a second timer associated with the DNN and no S-NSSAI in the at least one backoff timer. Additionally or alternatively, if the timer value does not indicate zero, the terminal device 201 may start the second timer associated with the DNN and no S-NSSAI with the timer value.
[0109] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN. In these embodiments, if / when / based on the terminal device 201 provided the S-NSSAI and did not provide any DNN during establishment of the session, the at least one backoff timer comprises the second timer (e.g., T3584). The terminal device 201 may stop a second timer associated with the S-NSSAI and no DNN in the at least one backoff timer. Additionally or alternatively, if the timer value does not indicate zero, the terminal device 201 may start the second timer associated with the S-NSSAI and no DNN with the timer value.
[0110] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN. In these embodiments, if / when / based on the terminal device 201 did not provide any DNN or any S-NSSAI during establishment of the session, the at least one backoff timer comprises the second timer (e.g., T3584). The terminal device 201 may stop a second timer associated withno S-NSSAI and no DNN in the at least one backoff timer. Additionally or alternatively, if the timer value does not indicate zero, the terminal device 201 may start the second timer associated with no DNN and no S-NSSAI with the timer value.
[0111] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI. In these embodiments, if / when / based on the terminal device 201 provided the S-NSSAI during establishment of the session, the at least one backoff timer comprises the third timer (e.g., T3585). The terminal device 201 may stop a third timer associated with the S-NSSAI in at least one backoff timer. Additionally or alternatively, if the timer value does not indicate zero, the terminal device 201 may start the third timer associated with the S-NSSAI with the timer value.
[0112] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI. In these embodiments, if / when / based on the terminal device 201 did not provide any S-NSSAI during establishment of the session, the at least one backoff timer comprises the third timer (e.g., T3585). The terminal device 201 may stop a third timer associated with no S-NSSAI in the at least one backoff timer. Additionally or alternatively, if the timer value does not indicate zero, the terminal device 201 may start the third timer associated with no S-NSSAI with the timer value.
[0113] In some embodiments, the terminal device may keep the third timer running in case of a PLMN change or an inter-system change.
[0114] Timer value indicating deactivated
[0115] In some embodiments, the timer value indicates the timer is deactivated. The terminal device terminal device 201 may stop the at least one backoff timer and keep the at least one backoff timer as deactivated. In some embodiments, the at least one backoff timer may comprise at least one of the first timer (T3396), the second timer (T3584), and the third timer (T3585).
[0116] In some embodiments, the indication indicates the congestion is in the data network identified by the DNN. In these embodiments, if / when / based on the terminal device 201 provided the DNN during establishment of the session, the at least one backoff timer comprises the first timer (e.g., T3396). The terminal device 201 may stop a first timer associated with the DNN in the at least one backoff timer. Additionally, the terminal device 201 may keep the first timer associated with the DNN as deactivated.
[0117] In some embodiments, the indication indicates the congestion is in the data network identified by the DNN. In these embodiments, if / when / based on the terminal device 201 did not provide any DNN during establishment of the session, the at least one backoff timer comprises the first timer (e.g., T3396). The terminal device 201 may stop a first timer associated with no DNN in the at least one backoff timer. Additionally, the terminal device 201 may keep the first timer associated with no DNN as deactivated.
[0118] In some embodiments, the terminal device 201 may keep the first timer as deactivated in case of a PLMN change or an inter-system change.
[0119] In some embodiments, the indication indicates the congestion is in the data network identified by the DNN and the network slice identified by the S-NSSAI. In t these embodiments, if / when / based on the terminal device 201 provided the DNN and the S-NSSAI during establishment of the session, the at least one backoff timer comprises the second timer (e.g., T3584). The terminal device 201 may stop a second timer associated with the DNN and the S-NSSAI in the at least one backoff timer. Additionally, the terminal device 201 may keep the second timer associated with the DNN and the S-NSSAI as deactivated.
[0120] In some embodiments, the indication indicates the congestion is in the data network identified by the DNN and the network slice identified by the S-NSSAI. In these embodiments, if / when / based on the terminal device 201 provided the DNN and did not provide any S-NSSAI during establishment of the session, the at least one backoff timer comprises the second timer (e.g., T3584). The terminal device 201 may stop a second timer associated with the DNN and no S-NSSAI in the at least one backoff timer. Additionally, the terminal device 201 may keep the second timer associated with the DNN and no S-NSSAI as deactivated.
[0121] In some embodiments, the indication indicates the congestion is in the data network identified by the DNN and the network slice identified by the S-NSSAI. In these embodiments, if / when / based on the terminal device 201 did not provide any DNN and provided S-NSSAI during establishment of the session, the at least one backoff timer comprises the second timer (e.g., T3584). The terminal device 201 may stop a second timer associated with S-NSSAI and no DNN in the at least one backoff timer. Additionally, the terminal device 201 may keep the second timer associated with S-NSSAI and no DNN as deactivated.
[0122] In some embodiments, the indication indicates the congestion is in the data networkidentified by the DNN and the network slice identified by the S-NSSAI. In these embodiments, if / when / based on the terminal device 201 did not provide any DNN or S-NSSAI during establishment of the session, the at least one backoff timer comprises the second timer (e.g., T3584). The terminal device 201 may stop a second timer associated with no S-NSSAI and no DNN in the at least one backoff timer. Additionally, the terminal device 201 may keep the second timer associated with no S-NSSAI and no DNN as deactivated.
[0123] In some embodiments, the terminal device 201 may keep the second timer as deactivated in case of a PLMN change or an inter-system change.
[0124] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI. In these embodiments, if / when / based on the terminal device 201 provided the S-NSSAI during establishment of the session, the at least one backoff timer comprises the third timer (e.g., T3585). The terminal device 201 may stop a third timer associated with the S-NSSAI in at least one backoff timer. Additionally, the terminal device 201 may keep the third timer associated with the S-NSSAI as deactivated.
[0125] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI. In these embodiments, if / when / based on the terminal device 201 did not provide any S-NSSAI during establishment of the session, the at least one backoff timer comprises the third timer (e.g., T3585). The terminal device 201 may stop a third timer associated with no S-NSSAI in at least one backoff timer. Additionally, the terminal device 201 may keep the third timer associated with no S-NSSAI as deactivated.
[0126] In some embodiments, the third timer is applied for a plurality of PLMNs and for a 3GPP access type. Additionally or alternatively, the third timer is applied for the plurality of PLMNs and for both the 3GPP access type and a non-3GPP access type. Additionally or alternatively, the third timer is applied for a registered PLMN of the plurality of PLMNs and for the 3GPP access type. Additionally or alternatively, the third timer is applied for the registered PLMN of the plurality of PLMNs and for the 3GPP access type and the non-3GPP access type.
[0127] In some embodiments, the timer associated with no DNN refers to a timer not associated with any DNN or a timer unassociated with any DNN. Similarly, the timer associated with no S-NSSAI refers to a timer not associated with any S-NSSAI or a timer unassociated with any S-NSSAI.
[0128] Now move back to the FIG. IB, under a congestion condition, the network device(for example, the SM NF 130 and / or the MM SF 120) may have a means to back off (data (re)transmissions from) the terminal device 110 and the network device can even decide for how long the terminal device 110 is to be backed off.
[0129] In some scenarios, if the congestion condition is resolved earlier than expected (i.e., while the backoff timer is running in the terminal device 110 and the terminal device 110 does not send any uplink SM message for the DNN and / or S-NSSAI associated with the timer), the network device (for example, the SM NF 130) may send a downlink SM message to the terminal device 110 and the terminal device 110 may stop the timer (and start data (re)transmissions). For example, the terminal device 110 may stop at least one of the timers T3396, T3584, and T3585 are timers associated with a DNN, combination of a DNN and an S-NSSAI, and an S-NSSAI, respectively.
[0130] Note that transmission of a DL NAS TRANSPORT message including user data for a session associated with a DNN and / or an S-NSSAI implies that a congestion situation in the data network identified by the DNN and / or the network slice identified by the S-NSSAI has been resolved. However, the terminal device 110 (a CIoT device) which has previously received an indication / cause value indicating that not enough resources are available, does not stop the relevant timers (i.e., T3396, T3585 and T3584 (if running), associated with network slice (S-NSSAI) or DNN) (e.g., based on the existing mechanisms).
[0131] As mentioned above, the terminal device 110 starts the at least one backoff timer with timer value based on the indication, the timer value and the ID of the session. For example, the terminal device 110 may receive an indication from the network (e.g., identified by DNN / S-NSSAI) is congested for an expected period of time (e.g., one hour). Based on that indication, the terminal device 110 may start a certain set of timers (i.e., T3396 and / or T3585 and / or T3584) which prevents the terminal device 110 to send UL data while the timers are running.
[0132] In view of this, some example embodiments of the disclosure also propose that upon / after receiving a second message (DL NAS TRANSPORT message) which includes user data (second data) and a session ID, the terminal device 110 may stop the relevant timers (i.e., T3396 and / or T3585 and / or T3584).
[0133] Specificallyy, in some example embodiments of FIG. 2, the terminal device 201 may receive, at the first sublayer 201-2, a second message which comprises second data and the ID of the session and is without any cause value (after 230). The terminal device 201may receive, at the second sublayer 201-1 from the first sublayer 201-2, the second data and the ID of the session. The terminal device 201 may stop the at least one backoff timer based on the reception of the second data and the ID of the session based on that the at least one backoff timer is running.
[0134] For example, the terminal device 201 may stop the running third timer (T3585). The timer T3585 is applied for a plurality of PLMNs and for a 3GPP access type. Additionally or alternatively, the timer T3585 is applied for the plurality of PLMNs and for both the 3GPP access type and a non-3GPP access type. Additionally or alternatively, the timer T3585 is applied for a registered PLMN of the plurality of PLMNs and for the 3GPP access type. Additionally or alternatively, the timer T3585 is applied for the registered PLMN of the plurality of PLMNs and for the 3GPP access type and the non-3GPP access type.
[0135] The second message may be DL NAS TRANSPORT message. The second data may be second CIoT user data (user data).
[0136] For example, the terminal device 201 may select a running timer to stop (i.e., the first timer (T3396) and / or the second timer (T3584) and / or the third timer (T3585)) using a DNN and / or an S-NSSAI which the terminal device 201 provided during the establishment of a session identified by the session ID. If the terminal device 201 provided no DNN and / or no S-NSSAI during the establishment of the session, a timer associated with no DNN and / or no S-NSSAI is selected. The more details will be discussed with the FIGS. 3 and 4.
[0137] In this way, it will enable the terminal device 201 to send uplink SM messages and user data via control plane for a session which is associated with the DNN (or no DNN) and / or the S-NSSAI (or no S-NSSAI), after the previous congestion issues have been solved / eased. Therefore, the terminal device 201 can transmit UL data before the running timers triggered by the prior congestion indication expired. The efficiency and the performance of the communication are increased, therefore.
[0138] In some embodiments, the terminal device 201 may set “tl” be time remaining for timer timeout at switch off and “f ’ be time elapsed between switch off and switch on based on determining that the terminal device is switched off when the at least one backoff timer is running and a USIM in the terminal device is unchanged.
[0139] The terminal device 201 may then restart the at least one backoff timer with a value of tl minus t based on determining that the tl is greater than t.
[0140] Alternatively, the terminal device 201 may then avoid the at least one backoff timer to be restarted based on determining that tl is equal to or less than t.
[0141] Alternatively, the terminal device 201 may then restart the at least one backoff timer with the value tl based on determining that the terminal device is not capable of determining t.
[0142] In this way, the terminal device 201 may handle, notification and message exchange with network, and take appropriate action for the backoff timer control depending on the message received. Additionally, the terminal device 201 may be able to determine the appropriate data network identified by the DNN and / or S-NSSAI for which the congestion control applies.
[0143] Additionally, the terminal device 201 may be able to stop the backoff timer if any of them were running and can transmit UL data before the previously defined congestion timer has expired.
[0144] Therefore, the efficiency and performance of the communication (for example, CIoT communication) between the terminal device and the network device (for example, the SMF and / or AMF) may be improved.
[0145] FIG. 3 illustrates a signaling diagram illustrating an example of another process 300 for timer control for congestion handling according to some embodiments of the present disclosure. For the purpose of discussion, the process 300 will be described with reference to FIG. 1 A. The process 300 may involve the terminal device 301 comprising SM sublayer 301-1 and MM sublayer 301-2, and MM NF 302. The MM sublayer 301-2 may be the MM sublayer 110-2 and the SM sublayer 301-1 may be the SM sublayer 110-1. The terminal device 301 may be the terminal device 110 and the MM NF 302 may be the MM NF 120 as illustrated in FIG. 1 A.
[0146] In FIG. 3, at 310, the terminal device 301 may receive, at a mobility management MM sublayer 301-2 of the terminal device 301, a first message comprising first CIoT user data, an ID of a PDU session, an MM cause value and a timer value.
[0147] At 320, the terminal device 301 may transmit, from the MM sublayer 301-2 of the terminal device 301 to a SM sublayer 301-1 of the terminal device 301, the first CIoT user data, the ID of the PDU session, an indication and the timer value. The indication is based on the MM cause value and indicates congestion in at least one of a data network identifiedby a DNN or a network slice identified by a S-NSSAI.
[0148] At 330, the terminal device 301 may start at least one backoff timer based on the indication, the timer value and the ID of the PDU session. The at least one backoff timer comprises at least one of a timer T3396, a timer T3584 and a timer T3585.
[0149] In some embodiments, the timer value indicates neither zero nor the timer is deactivated. The terminal device 301 may stop the at least one backoff timer and start the at least one backoff timer with the timer value.
[0150] In some embodiments, the at least one backoff timer comprises the timer T3396. The indication indicates the congestion is in the data network identified by the DNN and the terminal device 301 provided the DNN during establishment of the PDU session. The terminal device 301 may stop the timer T3396 associated with the DNN in the at least one backoff timer and start the timer T3396 associated with the DNN with the timer value.
[0151] In some embodiments, the at least one backoff timer comprises the timer T3396. The indication indicates the congestion is in the data network identified by the DNN and the terminal device 301 did not provide the DNN during establishment of the PDU session. The terminal device 301 may stop the timer T3396 associated with no DNN in the at least one backoff timer and start the timer T3396 associated with no DNN with the timer value.
[0152] In some embodiments, the terminal device 301 may keep the timer T3396 running based on a public land mobile network (PLMN) change or an inter-system change.
[0153] In some embodiments, the at least one backoff timer comprises the timer T3584. The indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN and the terminal device 301 provided the DNN and the S-NSSAI during establishment of the PDU session. The terminal device 301 may stop the timer T3584 associated with the DNN and the S-NSSAI in the at least one backoff timer and start the timer T3584 associated with the DNN and the S-NSSAI with the timer value.
[0154] In some embodiments, the at least one backoff timer comprises the timer T3584. The indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN and the terminal device 301 provided the DNN and did not provide any S-NSSAI. The terminal device 301 may stop the timer T3584 associated with the DNN and no S-NSSAI in the at least one backoff timer and start the timerT3584 associated with the DNN and no S-NSSAI with the timer value.
[0155] In some embodiments, the at least one backoff timer comprises the timer T3584. The indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN and the terminal device 301 provided the DNN and did not provide any S-NSSAI during establishment of the PDU session. The terminal device 301 may stop the timer T3584 associated with the DNN and no S-NSSAI in the at least one backoff timer and start the timer T3584 associated with the DNN and no S-NSSAI with the timer value.
[0156] In some embodiments, the at least one backoff timer comprises the timer T3584. The indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN and the terminal device 301 provided the S-NSSAI and did not provide any DNN during establishment of the PDU session. The terminal device 301 may stop the timer T3584 associated with the S-NSSAI and no DNN in the at least one backoff timer and start the timer T3584 associated with the S-NSSAI and no DNN with the timer value.
[0157] In some embodiments, the at least one backoff timer comprises the timer T3584. The indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN and the terminal device 301 provided the S-NSSAI and did not provide any DNN during establishment of the PDU session. The terminal device 301 may stop the timer T3584 associated with the S-NSSAI and no DNN in the at least one backoff timer and start the timer T3584 associated with the S-NSSAI and no DNN with the timer value.
[0158] In some embodiments, the at least one backoff timer comprises the timer T3584. The indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN and the terminal device 301 did not provide any DNN or any S-NSSAI during establishment of the PDU session. The terminal device 301 may stop the timer T3584 associated with no S-NSSAI and no DNN in the at least one backoff timer and start the timer T3584 associated with no DNN and no S-NSSAI with the timer value.
[0159] In some embodiments, the at least one backoff timer comprises the timer T3585. The indication indicates the congestion is in the network slice identified by the S-NSSAI and the terminal device 301 provided the S-NSSAI during establishment of the PDU session.The terminal device 301 may stop the timer T3585 associated with the S-NSSAI in at least one backoff timer and start the timer T3585 associated with the S-NSSAI with the timer value.
[0160] In some embodiments, the at least one backoff timer comprises the timer T3585. The indication indicates the congestion is in the network slice identified by the S-NSSAI and the terminal device did not provide any S-NSSAI during establishment of the PDU session. The terminal device 301 may stop the timer T3585 associated with the S-NSSAI in at least one backoff timer and start the timer T3585 associated with no S-NSSAI with the timer value.
[0161] In some embodiments, the timer T3585 is applied for a plurality of PLMNs and for a 3GPP access type. Additionally or alternatively, the timer T3585 is applied for the plurality of PLMNs and for both the 3GPP access type and a non-3GPP access type. Additionally or alternatively, the timer T3585 is applied for a registered PLMN of the plurality of PLMNs and for the 3GPP access type. Additionally or alternatively, the timer T3585 is applied for the registered PLMN of the plurality of PLMNs and for the 3GPP access type and the non-3 GPP access type.
[0162] There may also exist the same mentioned above problem which is: transmission of a DL NAS TRANSPORT message including user data for a session associated with a DNN and / or an S-NSSAI implies that a congestion situation in the data network identified by the DNN and / or the network slice identified by the S-NSSAI has been resolved. However, the terminal device 110 (a CIoT device) which has previously received an indication / cause value indicating that not enough resources are available, does not stop the relevant timers (i.e., T3396, T3585 and T3584 (if running), associated with network slice (S-NSSAI) or DNN).
[0163] In view of this, some embodiments of the disclosure also propose that upon receiving a second message (DLNAS TRANSPORT message) which includes user data and a session ID, the terminal device 110 may stop the relevant timers (i.e., T3396, T3585 and / or T3584).
[0164] In some embodiments, the terminal device 301 may receive, at the MM sublayer 301-2, a second message (DL NAS TRANSPORT message) which comprises second CIoT user data and the ID of the PDU session and is without any MM cause value. The terminal device 201 may receive, at the SM sublayer 301-1 from the MM sublayer 301-2, the second CIoT user data and the ID of the PDU session. The terminal device 301 may stop the at leastone backoff timer based on the reception of the second data and the ID of the session based on that the at least one backoff timer is running.
[0165] For example, the terminal device 301 may stop the running third timer (T3585). The timer T3585 is applied for a plurality of PLMNs and for a 3GPP access type. Additionally or alternatively, the timer T3585 is applied for the plurality of PLMNs and for both the 3GPP access type and a non-3GPP access type. Additionally or alternatively, the timer T3585 is applied for a registered PLMN of the plurality of PLMNs and for the 3GPP access type. Additionally or alternatively, the timer T3585 is applied for the registered PLMN of the plurality of PLMNs and for the 3GPP access type and the non-3GPP access type. The more details will be discussed with the FIG. 4 later.
[0166] In this way, it will enable the terminal device 301 to send uplink SM messages and user data via control plane for a session which is associated with the DNN (or no DNN) and / or the S-NSSAI (or no S-NSSAI), which is not congested anymore. Therefore, the terminal device 301 can transmit UL data before the prior congestion indication has expired which will improve the efficiency and the performance of the communication.
[0167] In some embodiments, the terminal device 301 may set tl be time remaining for timer timeout at switch off and t be time elapsed between switch off and switch on based on determining that the terminal device is switched off when the at least one backoff timer is running and a USIM in the terminal device is unchanged.
[0168] The terminal device 301 may then restart the at least one backoff timer with a value of tl minus t based on determining that the tl is greater than t.
[0169] Alternatively, the terminal device 301 may then avoid the at least one backoff timer to be restarted based on determining that tl is equal to or less than t.
[0170] Alternatively, the terminal device 301 may then restart the at least one backoff timer with the value tl based on determining that the terminal device is not capable of determining t.
[0171] In this way, the terminal device 301 may handle, notification and message exchange with network, and take appropriate action for the backoff timer control depending on the message received. Additionally, the terminal device 301 may be able to determine the appropriate data network identified by the DNN and / or S-NSSAI for which the congestion control applies.
[0172] Additionally, the terminal device 301 may be able to stop the backoff timer if any of them were running and can transmit UL data before the previously defined congestion timer has expired.
[0173] Therefore, the efficiency and performance of the communication (for example, CIoT communication) between the terminal device and the network device (for example, the SMF and / or AMF) may be improved.
[0174] FIG. 4 illustrates a signaling diagram illustrating an example of process 400 for timer control for congestion handling according to some embodiments of the present disclosure. For the purpose of discussion, the process 400 will be described with reference to FIG. 1 A. The process 400 may involve the terminal device 401 comprising SM sublayer 401-1 and MM sublayer 401-2, SM NF 403 and MM NF 402 . The (5G) MM sublayer 401-2 may be the MM sublayer 101-2 and the (5G) SM sublayer 401-1 may be the SM sublayer 101-1. The UE 401 may be the terminal device 110, the SM MF 403 may be the SMNF 130, and the MM NF 402 may be the MM NF 120 as illustrated in FIG. 1 A.
[0175] At 411, the SM sublayer 401-1 in the UE 401 may identify a need to send user data over control plane (e.g., CIoT user data) for a session.
[0176] At 412, the SM sublayer 401-1 may send the user data for the session to another sublayer in the UE 401, the MM sublayer 401-2. In addition to the user data, the SM sublayer 401-1 may provide the MM sublayer 401-2 with an identifier or identity for the session (session ID).
[0177] At 413, the MM sublayer 401-2 may create an UL NAS TRANSPORT message. The UL NAS TRANSPORT message may include the user data and the session ID. The MM sublayer 401-2 may send the UL NAS TRANSPORT message to the MM NF 302 in the mobile communication network.
[0178] At 414, the MM NF 402 may determine that there is congestion in a data network identified by a DNN and / or in a network slice identified by an S-NSSAI. The DNN and the S-NSSAI are associated with the session identified by the session ID.
[0179] At 415, the MM NF 402 may create a DL NAS TRANSPORT message. The DL NAS TRANSPORT message includes an MM cause value, a timer value, and the session ID. The MM NF 402 may send the DLNAS TRANSPORT message to the UE 401.
[0180] At 416, the MM sublayer 401-2 may determine the indication based on the MMcause value. The MM sublayer 401-2 may send the session ID, the indication and the timer value to the SM sublayer 401-1.
[0181] For example, upon reception of a DL NAS TRANSPORT message, if the Payload container type IE is set to "CIoT user data container". Additionally, the 5GMM cause IE is set to the 5GMM cause #22 "Congestion" (MM cause value), the UE passes to the 5GSM sublayer 401-1 an indication that the CIoT user data was not forwarded due to DNN based congestion control along with the CIoT user data from the Payload container IE, the timer value from the Back-off timer value IE, and the PDU session ID from the PDU session ID IE of the DL NAS TRANSPORT message
[0182] Alternatively, upon reception of a DLNAS TRANSPORT message, if the Payload container type IE is set to "CIoT user data container". Additionally, the 5GMM cause IE is set to the 5GMM cause #67 "insufficient resources for specific slice and DNN", the UE 401 passes to the 5GSM sublayer 401-1 an indication that the CIoT user data was not forwarded due to S-NSSAI and DNN based congestion control along with the CIoT user data from the Payload container IE, the timer value from the Back-off timer value IE, and the PDU session ID from the PDU session ID IE of the DL NAS TRANSPORT message.
[0183] Alternatively, upon reception of a DLNAS TRANSPORT message, if the Payload container type IE is set to "CIoT user data container". Additionally, the 5GMM cause IE is set to the 5GMM cause #69 "insufficient resources for specific slice", the UE 401 passes to the 5GSM sublayer 401-1 an indication that the CIoT user data was not forwarded due to S-NSSAI only based congestion control along with the CIoT user data from the Payload container IE, the timer value from the Back-off timer value IE, and the PDU session ID from the PDU session ID IE of the DL NAS TRANSPORT message.
[0184] At 417, the SM sublayer 401-1 may perform at least one action for the at least one backoff timer depending on the session ID, indication, and timer value received from the MM sublayer 401-2.
[0185] Upon receiving the message comprising the indication, the session ID and the timer value, the SM layer may process the session ID (PDU session ID) and activate the back-off timer as per the DNN and / or NSSAI information in PDU Session ID. Also the SM layer may also stop and / or deactivate the back-off timer as per the DNN and / or NSSAI information in PDU Session ID.
[0186] For example, the SM layer 401-1 may handle the timers T3396 in case of congestion,T3584 in case of "insufficient resources for specific slice and DNN" and T3585 in case of "insufficient resources for specific slice", as per the received PDU session ID and the timer value.
[0187] More specifically, if an indication that the CIoT user data container was not forwarded due to DNN based congestion control is received from the 5GMM sublayer 401-2 along with CIoT user data, a timer value, and a PDU session ID, the UE 401 shall take different actions depending on the timer value received from the 5GMM sublayer 401-2 as follows: a) If the timer value indicates neither zero nor deactivated and:1) The UE 401 provided a DNN during the establishment of the PDU session identified by the PDU session ID, the UE 401 shall stop timer T3396 associated with the DNN, if it is running, and start timer T3396 with the timer value for the DNN; or2) The UE 401 did not provide a DNN during the establishment of the PDU session identified by the PDU session ID, the UE 401 shall stop timer T3396 associated with no DNN, if it is running, and start timer T3396 with the timer value for no DNN.
[0188] In some embodiments, the UE 401 shall not stop the timer T3396 upon a PLMN change or inter-system change.
[0189] Alternatively, if an indication that the CIoT user data container was not forwarded due to DNN based congestion control is received from the 5GMM sublayer 401-2 along with CIoT user data, a timer value, and a PDU session ID, the UE 401 shall take different actions depending on the timer value received from the 5GMM sublayer 401-2 as follows: b) If the timer value indicates that the timer is deactivated and:1) The UE 401 provided a DNN during the establishment of the PDU session identified by the PDU session ID, the UE 401 shall stop timer T3396 associated with the DNN, if it is running, and keep the timer T3396 deactivated; or2) The UE 401 did not provide a DNN during the establishment of the PDU session identified by the PDU session ID, the UE 401 shall stop timer T3396 associated with no DNN, if it is running, and keep the timer T3396 deactivated.
[0190] In some embodiments, the UE 401 shall keep the timer T3396 deactivated upon a PLMN change or inter-system change.
[0191] Alternatively, if an indication that the CIoT user data container was not forwarded due to DNN based congestion control is received from the 5GMM sublayer 401-2 along withCIoT user data, a timer value, and a PDU session ID, the UE 401 shall take different actions depending on the timer value received from the 5GMM sublayer 401-2 as follows: c) If the timer value indicates zero and:1) The UE 401 provided a DNN during the establishment of the PDU session identified by the PDU session ID, the UE 401 shall stop timer T3396 associated with the DNN, if it is running, and keep the timer T3396 deactivated; or2) The UE 401 did not provide a DNN during the establishment of the PDU session identified by the PDU session ID, the UE 401 shall stop timer T3396 associated with no DNN, if it is running, and keep the timer T3396 deactivated.
[0192] Alternatively, if an indication that the CIoT user data container was not forwarded due to DNN based congestion control is received from the 5GMM sublayer 401-2 along with CIoT user data, a timer value, and a PDU session ID, the UE 401 shall take different actions depending on the timer value received from the 5GMM sublayer 401-2 as follows: c) If the timer value indicates zero and:1) The UE 401 provided a DNN during the establishment of the PDU session identified by the PDU session ID, the UE 401 shall stop timer T3396 associated with the DNN, if it is running; or2) The UE 401 did not provide a DNN during the establishment of the PDU session identified by the PDU session ID, the UE 401 shall stop timer T3396 associated with no DNN, if it is running.
[0193] In some embodiments, if the timer T3396 is running when the UE 401 enters state 5GMM-DEREGISTERED, the UE 401 remains switched on, and the USIM in the UE 401 remains the same, then the timer T3396 is kept running until it expires or is stopped.
[0194] In some embodiments, if the UE 401 is switched off when the timer T3396 is running and the USIM in the UE 401 remains the same, then the UE 401 shall behave as follows: let tl be the time remaining for the timer T3396 timeout at switch off and let “f ’ be the time elapsed between switch off and switch on. If tl is greater than t, then the timer shall be restarted with the value tl minus t. If tl is equal to or less than t, then the timer need not be restarted. If the UE 401 is not capable of determining t, then the UE 401 shall restart the timer with the value tl .
[0195] If an indication that the CIoT user data container was not forwarded due to S-NSSAIand DNN based congestion control is received from the 5GMM sublayer 401-2 along with CIoT user data, a timer value, and a PDU session ID, the UE 401 shall take different actions depending on the timer value received from the 5GMM sublayer 401-2 as follows: a) If the timer value indicates neither zero nor deactivated and:1) The UE 401 provided a DNN and an S-NSSAI during the establishment of the PDU session identified by the PDU session ID, the UE 401 shall stop timer T3584 associated with [the DNN, the S-NSSAI] combination, if it is running, and start timer T3584 with the timer value for [the DNN, the S-NSSAI] combination;2) The UE 401 provided an S-NSSAI and did not provide a DNN during the establishment of the PDU session identified by the PDU session ID, the UE 401 shall stop timer T3584 associated with [no DNN, the S-NSSAI] combination, if it is running, and start timer T3584 with the timer value for [no DNN, the S-NSSAI] combination;3) The UE 401 provided a DNN and did not provide an S-NSSAI during the establishment of the PDU session identified by the PDU session ID, the UE 401 shall stop timer T3584 associated with [the DNN, no S-NSSAI] combination, if it is running, and start timer T3584 with the timer value for [the DNN, no S-NSSAI] combination; or4) The UE 401 did not provide a DNN or an S-NSSAI during the establishment of the PDU session identified by the PDU session ID, the UE 401 shall stop timer T3584 associated with [no DNN, no S-NSSAI] combination, if it is running, and start timer T3584 with the timer value for [no DNN, no S-NSSAI] combination.
[0196] Alternatively, if an indication that the CIoT user data container was not forwarded due to S-NSSAI and DNN based congestion control is received from the 5GMM sublayer 401-2 along with CIoT user data, a timer value, and a PDU session ID, the UE 401 shall take different actions depending on the timer value received from the 5GMM sublayer 401-2 as follows: b) If the timer value indicates that the timer is deactivated and:1) The UE 401 provided a DNN and an S-NSSAI during the establishment of the PDU session identified by the PDU session ID, the UE 401 shall stop timer T3584 associated with [the DNN, the S-NSSAI] combination, if it is running, and keep the timer T3584 deactivated; 2) The UE 401 provided an S-NSSAI and did not provide a DNN during the establishment of the PDU session identified by the PDU session ID, the UE 401 shall stop timer T3584 associated with [no DNN, the S-NSSAI] combination, if it is running, and keep the timerT3584 deactivated;3) The UE 401 provided a DNN and did not provide an S-NSSAI during the establishment of the PDU session identified by the PDU session ID, the UE 401 shall stop timer T3584 associated with [the DNN, no S-NSSAI] combination, if it is running, and keep the timer T3584 deactivated; or4) The UE 401 did not provide a DNN or an S-NSSAI during the establishment of the PDU session identified by the PDU session ID, the UE 401 shall stop timer T3584 associated with [no DNN, no S-NSSAI] combination, if it is running, and keep the timer T3584 deactivated.
[0197] In some embodiments, the UE 401 shall keep timer T3584 deactivated upon a PLMN change or inter-system change.
[0198] Alternatively, if an indication that the CIoT user data container was not forwarded due to S-NSSAI and DNN based congestion control is received from the 5GMM sublayer 401-2 along with CIoT user data, a timer value, and a PDU session ID, the UE 401 shall take different actions depending on the timer value received from the 5GMM sublayer 401-2 as follows: c) If the timer value indicates zero and:1) The UE 401 provided a DNN and an S-NSSAI during the establishment of the PDU session identified by the PDU session ID, the UE 401 shall stop timer T3584 associated with [the DNN, the S-NSSAI] combination, if it is running;2) The UE 401 provided an S-NSSAI and did not provide a DNN during the establishment of the PDU session identified by the PDU session ID, the UE 401 shall stop timer T3584 associated with [no DNN, the S-NSSAI] combination, if it is running;3) The UE 401 provided a DNN and did not provide an S-NSSAI during the establishment of the PDU session identified by the PDU session ID, the UE 401 shall stop timer T3584 associated with [the DNN, no S-NSSAI] combination, if it is running; or4) The UE 401 did not provide a DNN or an S-NSSAI during the establishment of the PDU session identified by the PDU session ID, the UE 401 shall stop timer T3584 associated with [no DNN, no S-NSSAI] combination, if it is running.
[0199] In some embodiments, the timer T3584 to be stopped includes the timer T3584 applied for all the PLMNs, if running, and the timer T3584 applied for the registered PLMN, if running.
[0200] In some embodiments, if the timer T3584 is running when the UE 401 enters state5GMM-DEREGISTERED, the UE 401 remains switched on, and the USIM in the UE 401 remains the same, then the timer T3584 is kept running until it expires or is stopped.
[0201] In some embodiments, if the UE 401 is switched off when the timer T3584 is running and the USIM in the UE 401 remains the same, then the UE 401 shall behave as follows: let tl be the time remaining for the timer T3584 timeout at switch off and let “t” be the time elapsed between switch off and switch on. If tl is greater than t, then the timer shall be restarted with the value tlminus t. If tl is equal to or less than t, then the timer need not be restarted. If the UE 401 is not capable of determining t, then the UE 401 shall restart the timer with the value tl .
[0202] If an indication that the CIoT user data container was not forwarded due to S-NSSAI only based congestion control is received from the 5GMM sublayer 401-2 along with CIoT user data, a timer value, and a PDU session ID, the UE 401 shall take different actions depending on the timer value received from the 5GMM sublayer 401-2 as follows: a) If the timer value indicates neither zero nor deactivated and:1) The UE 401 provided an S-NSSAI during the establishment of the PDU session identified by the PDU session ID, the UE 401 shall stop timer T3585 associated with the S-NSSAI, if it is running, and start timer T3396 with the timer value for the S-NSSAI; or 2) The UE 401 did not provide an S-NSSAI during the establishment of the PDU session identified by the PDU session ID, the UE 401 shall stop timer T3585 associated with no S-NSSAI, if it is running, and start timer T3585 with the timer value for no S-NSSAI.
[0203] In some embodiments, the UE 401 shall not stop the timer T3585 upon a PLMN change or inter-system change.
[0204] Alternatively, if an indication that the CIoT user data container was not forwarded due to S-NSSAI only based congestion control is received from the 5GMM sublayer 401-2 along with CIoT user data, a timer value, and a PDU session ID, the UE 401 shall take different actions depending on the timer value received from the 5GMM sublayer 401-2 as follows: b) If the timer value indicates that the timer is deactivated and:1) The UE 401 provided an S-NSSAI during the establishment of the PDU session identified by the PDU session ID, the UE 401 shall stop timer T3585 associated with the S-NSSAI, if it is running, and keep the timer T3585 deactivated; or2) The UE 401 did not provide an S-NSSAI during the establishment of the PDU sessionidentified by the PDU session ID, the UE 401 shall stop timer T3585 associated with no S-NSSAI, if it is running, and keep the timer T3585 deactivated.
[0205] In some embodiments, the UE 401 shall keep the timer T3585 deactivated upon a PLMN change or inter-system change.
[0206] Alternatively, if an indication that the CIoT user data container was not forwarded due to S-NSSAI only based congestion control is received from the 5GMM sublayer 401-2 along with CIoT user data, a timer value, and a PDU session ID, the UE 401 shall take different actions depending on the timer value received from the 5GMM sublayer 401-2 as follows: c) If the timer value indicates zero and:1) The UE 401 provided an S-NSSAI during the establishment of the PDU session identified by the PDU session ID, the UE 401 shall stop timer T3585 associated with the S-NSSAI, if it is running; or2) The UE 401 did not provide an S-NSSAI during the establishment of the PDU session identified by the PDU session ID, the UE 401 shall stop timer T3585 associated with no S-NSSAI, if it is running.
[0207] In some embodiments, the timer to be stopped includes:a) the timer T3585 applied for all the PLMNs and for 3GPP access type, if running; b) the timer T3585 applied for all the PLMNs and for both 3GPP access type and non-3 GPP access type, if running;c) the timer T3585 applied for the registered PLMN and for 3GPP access type, if running; andd) the timer T3585 applied for the registered PLMN and for both 3GPP access type and non-3GPP access type, if running.
[0208] In some embodiments, if the timer T3585 is running when the UE 401 enters state 5GMM-DEREGISTERED, the UE 401 remains switched on, and the USIM in the UE 401 remains the same, then the timer T3585 is kept running until it expires or is stopped.
[0209] In some embodiments, if the UE 401 is switched off when the timer T3585 is running and the USIM in the UE 401 remains the same, then the UE 401 shall behave as follows: let tl be the time remaining for the timer T3585 timeout at switch off and let “t” be the time elapsed between switch off and switch on. If tl is greater than t, then the timer shallbe restarted with the value tlminus t. If tl is equal to or less than t, then the timer need not be restarted. If the UE 401 is not capable of determining t, then the UE 401 shall restart the timer with the value tl .
[0210] It can be seen that the UE 401 (CIoT device) has received a particular cause value (e.g., #22, #67 or #69 in current 4GS or 5GS) indicating that there are not enough available resources in 416. The UE 401 may start at least one backoff timer (T3396, T3585, or T3584) in 417. Under this indication, even if the UE 401 has UL data to transmit it cannot do it prior to the expiration of the congestion indication while the corresponding at least one backoff timer is running. To solve this problem, after the congestion is resolved, it may need another indication to stop the at least one running backoff timer.
[0211] Therefore, at 418, the network comprising SM NF 402 and MM NF 403 may determine that congestion condition does not apply anymore for a DNN and / or an S-NSSAI. The congestion may be resolved.
[0212] At 419, the SM NF 402 may need to send user data of a session associated with the DNN and / or the S-NSSAI to the UE 401. In order to send the user data, the SM NF 402 may invoke an MM NF service. In a request to invoke the MM NF service, the SM NF 402 may include user data and an identifier or identity of the session.
[0213] At 420, the MM NF 403 may send a DLNAS TRANSPORT message including the user data and the session ID and without any MM cause value.
[0214] At 421, the MM sublayer 401-2 may send the user data and the session ID to the SM sublayer 401-1.
[0215] At 422, the SM sublayer 401-1 in the UE 401 may stop the relevant backoff timers (in case they were running) as follows:
[0216] If the UE 401 provided a DNN and an S-NSSAI, the UE 401 shall stop timer T3396 associated with the DNN (if running), timer T3584 associated with [the DNN, the S-NSSAI] combination (if running), and timer T3585 associated with the S-NSSAI (if running).
[0217] Alternatively, if the UE 401 provided a DNN and did not provide an S-NSSAI, the UE 401 shall stop timer T3396 associated with the DNN (if running), timer T3584 associated with [the DNN, no S-NSSAI] combination (if running), and timer T3585 associated with no S-NSSAI (if running).
[0218] Alternatively, if the UE 401 provided an S-NSSAI and did not provide a DNN, theUE 401 shall stop timer T3396 associated with no DNN (if running), timer T3584 associated with [no DNN, the S-NSSAI] combination (if running), and timer T3585 associated with the S-NSSAI (if running).
[0219] Alternatively, if the UE 401 did not provide a DNN or an S-NSSAI, the UE 401 shall stop timer T3396 associated with no DNN (if running), timer T3584 associated with [no DNN, no S-NSSAI] combination (if running), and timer T3585 associated with no S-NSSAI (if running).
[0220] In some embodiments, the timer T3584 to be stopped includes the timer T3584 applied for all the PLMNs (if running), and the timer T3584 applied for the registered PLMN (if running).
[0221] In some embodiments, the timer T3585 (if running) is applied for a plurality of PLMNs and for a 3GPP access type. Additionally or alternatively, the timer T3585 (if running) is applied for the plurality of PLMNs and for both the 3GPP access type and a non-3GPP access type. Additionally or alternatively, the timer T3585 (if running) is applied for a registered PLMN of the plurality of PLMNs and for the 3GPP access type. Additionally or alternatively, the timer T3585 (if running) is applied for the registered PLMN of the plurality of PLMNs and for the 3GPP access type and the non-3GPP access type.
[0222] Upon stopping the relevant backoff timers in 422, the UE 401 can send uplink user data or an uplink SM message for the DNN (or no DNN) and / or the S-NSSAI (or no S-NSSAI).
[0223] Therefore, upon receiving a DL NAS TRANSPORT message including CIoT user data container (user data and session ID) and that does not include any MM cause value, the UE (terminal device or CIoT device) may stop the above-mentioned backoff timer if any of them were running and can transmit UL data before the previously defined congestion timer has expired which will increase the efficiency and reduce the transmission latency.
[0224] FIG. 5 illustrates a flowchart of a method 500 implemented at a terminal device according to some embodiments of the present disclosure. For the purpose of discussion, the method 500 will be described from the perspective of the terminal device 110 comprising the SM sublayer (also referred as SM sublayer entity) 110-1 and MM sublayer (also referred as MM sublayer entity) 110-2 with reference to FIG. 1 A. The first sublayer may be the MM sublayer 110-2 and the second sublayer may be the SM sublayer 110-1.
[0225] At block 510, the terminal device 110 may receive, at a first sublayer 110-2 of the terminal device 110, a first message comprising first data, an ID of a session, a cause value and a timer value.
[0226] At block 520, the terminal device 110 may transmit, from the first sublayer 110-2 of the terminal device 110 to a second sublayer 110-1 of the terminal device 110, the first data, the ID of the session, an indication and the timer value. The indication is based on the cause value and indicates congestion in at least one of a data network identified by a DNN or a network slice identified by S-NSSAI.
[0227] At block 530, the terminal device 110 may perform at least one action for at least one backoff timer based on the indication, the timer value and the ID of the session.
[0228] In some embodiments, the timer value does not indicate that the timer is deactivated. The terminal device is further caused to perform the at least one action by at least one of stopping the at least one backoff timer; or if the timer value does not indicate zero, starting the at least one backoff timer with the timer value.
[0229] In some embodiments, the terminal device is further caused to receive, at the first sublayer, a second message which comprises second data and the ID of the session and is without any cause value; receive, at the second sublayer 110-1 from the first sublayer, the second data and the ID of the session; and based on that the at least one backoff timer is running, stop the at least one backoff timer based on the reception of the second data and the ID of the session.
[0230] In some embodiments, the indication indicates the congestion is in the data network identified by the DNN. The terminal device provided the DNN during establishment of the session. The terminal device is caused to stop the at least one backoff timer by: stopping a first timer associated with the DNN in the at least one backoff timer, and wherein if the timer value does not indicate zero, the terminal device is caused to start the at least one backoff timer with the timer value by: starting the first timer associated with the DNN with the timer value.
[0231] In some embodiments, the indication indicates the congestion is in the data network identified by the DNN. The terminal device did not provide any DNN during establishment of the session. The terminal device is caused to stop the at least one backoff timer by: stopping a first timer associated with no DNN in the at least one backoff timer, and wherein if the timer value does not indicate zero, the terminal device is caused to start the at least onebackoff timer with the timer value by: starting the first timer associated with no DNN with the timer value.
[0232] In some embodiments, the terminal device is further caused to: keep the first timer running based on a PLMN change or an inter-system change.
[0233] In some embodiments, the first timer comprises a timer T3396.
[0234] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN. The terminal device provided the DNN and the S-NSSAI during establishment of the session, the terminal device is caused to stop the at least one backoff timer by: stopping a second timer associated with the DNN and the S-NSSAI in the at least one backoff timer, and wherein if the timer value does not indicate zero, the terminal device is caused to start the at least one backoff timer with the timer value by: starting the second timer associated with the DNN and the S-NSSAI with the timer value.
[0235] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN. The terminal device provided the DNN and did not provide any S-NSSAI during establishment of the session. The terminal device is caused to stop the at least one backoff timer by: stopping a second timer associated with the DNN and no S-NSSAI in the at least one backoff timer, and wherein if the timer value does not indicate zero, the terminal device is caused to start the at least one backoff timer with the timer value by: starting the second timer associated with the DNN and no S-NSSAI with the timer value.
[0236] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN. The terminal device provided the S-NSSAI and did not provide any DNN during establishment of the session, the terminal device is caused to stop the at least one backoff timer by: stopping a second timer associated with the S-NSSAI and no DNN in the at least one backoff timer, and wherein if the timer value does not indicate zero, the terminal device is caused to start the at least one backoff timer with the timer value by: starting the second timer associated with the S-NSSAI and no DNN with the timer value.
[0237] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN. The terminal device did not provide any DNN or any S-NSSAI during establishment of the session. The terminaldevice is caused to stop the at least one backoff timer by: stopping a second timer associated with no S-NSSAI and no DNN in the at least one backoff timer, and wherein if the timer value does not indicate zero, the terminal device is caused to start the at least one backoff timer with the timer value by: starting the second timer associated with no DNN and no S-NSSAI with the timer value.
[0238] In some embodiments, the second timer comprises a timer T3584.
[0239] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI. The terminal device provided the S-NSSAI during establishment of the session. The terminal device is caused to stop the at least one backoff timer by: stopping a third timer associated with the S-NSSAI in at least one backoff timer, and wherein if the timer value does not indicate zero, the terminal device is caused to start the at least one backoff timer with the timer value by: starting the third timer associated with the S-NSSAI with the timer value.
[0240] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI. The terminal device did not provide any S-NSSAI during establishment of the session. The terminal device is caused to stop the at least one backoff timer by: stopping a third timer associated with no S-NSSAI in the at least one backoff timer, and wherein if the timer value does not indicate zero, the terminal device is caused to start the at least one backoff timer with the timer value by: starting the third timer associated with no S-NSSAI with the timer value.
[0241] In some embodiments, the terminal device is further caused to: keep the third timer running in case of a PLMN change or an inter-system change.
[0242] In some embodiments, the third timer comprises a timer T3585.
[0243] In some embodiments, the timer value indicates the timer is deactivated. The terminal device is caused to perform the at least one action by: stopping the at least one backoff timer; and keeping the at least one backoff timer as deactivated.
[0244] In some embodiments, the indication indicates the congestion is in the data network identified by the DNN. The terminal device provided the DNN during establishment of the session. The terminal device is caused to stop the at least one backoff timer by: stopping a first timer associated with the DNN in the at least one backoff timer, and wherein the terminal device is caused to keep the at least one backoff timer as deactivated by: keeping the firsttimer associated with the DNN as deactivated.
[0245] In some embodiments, the indication indicates the congestion is in the data network identified by the DNN. The terminal device did not provide any DNN during establishment of the session. The terminal device is caused to stop the at least one backoff timer by: stopping a first timer associated with no DNN in the at least one backoff timer, and wherein the terminal device is caused to keep the at least one backoff timer as deactivated by: keeping the first timer associated with no DNN as deactivated.
[0246] In some embodiments, the terminal device is further caused to: keep the first timer as deactivated in case of a PLMN change or an inter-system change.
[0247] In some embodiments, the first timer comprises a timer T3396.
[0248] In some embodiments, the indication indicates the congestion is in the data network identified by the DNN and the network slice identified by the S-NSSAI. The terminal device provided the DNN and the S-NSSAI during establishment of the session. The terminal device is caused to stop the at least one backoff timer by: stopping a second timer associated with the DNN and the S-NSSAI in the at least one backoff timer, and wherein the terminal device is caused to keep the at least one backoff timer as deactivated by: keeping the second timer associated with the DNN and the S-NSSAI as deactivated.
[0249] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN. The terminal device provided the DNN and did not provide any S-NSSAI during establishment of the session. The terminal device is caused to stop the at least one backoff timer by: stopping a second timer associated with the DNN and no S-NSSAI in the at least one backoff timer, and wherein the terminal device is caused to keep the at least one backoff timer as deactivated by: keeping the second timer associated with the DNN and no S-NSSAI as deactivated.
[0250] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN. The terminal device did not provide any DNN and provided S-NSSAI during establishment of the session. The terminal device is caused to stop the at least one backoff timer by: stopping a second timer associated with S-NSSAI and no DNN in the at least one backoff timer, and wherein the terminal device is caused to keep the at least one backoff timer as deactivated by: keeping the second timer associated with the S-NSSAI and no DNN as deactivated.
[0251] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN. The terminal device did not provide any DNN or any S-NSSAI during establishment of the session. The terminal device is caused to stop the at least one backoff timer by: stopping a second timer associated with no S-NSSAI and no DNN in the at least one backoff timer, and wherein the terminal device is caused to keep the at least one backoff timer as deactivated by: keeping the second timer associated with no DNN and no S-NSSAI as deactivated.
[0252] In some embodiments, the terminal device is further caused to: keep the second timer as deactivated in case of a PLMN change or an inter-system change.
[0253] In some embodiments, the second timer comprises a timer T3584.
[0254] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI. The terminal device provided the S-NSSAI during establishment of the session. The terminal device is caused to stop the at least one backoff timer by: stopping a third timer associated with the S-NSSAI in at least one backoff timer, and wherein the terminal device is caused to keep the at least one backoff timer as deactivated by: keeping the third timer associated with the S-NSSAI as deactivated.
[0255] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI. The terminal device did not provide any S-NSSAI during establishment of the session. The terminal device is caused to stop the at least one backoff timer by: stopping a third timer associated with no S-NSSAI in the at least one backoff timer, and wherein the terminal device is caused to keep the at least one backoff timer as deactivated by: keeping the third timer associated with no S-NSSAI as deactivated.
[0256] In some embodiments, the terminal device is further caused to: keep the third timer as deactivated in case of a PLMN change or an inter-system change.
[0257] In some embodiments, at least one of: the third timer is applied for a plurality of PLMNs and for a 3GPP access type; the third timer is applied for the plurality of PLMNs and for both the 3GPP access type and a non-3GPP access type; the third timer is applied for a registered PLMN of the plurality of PLMNs and for the 3GPP access type; or the third timer is applied for the registered PLMN of the plurality of PLMNs and for the 3GPP access type and the non-3GPP access type.
[0258] In some embodiments, the third timer comprises a timer T3585.
[0259] In some embodiments, the terminal device is further caused to: based on determining that the terminal device is switched off when the at least one backoff timer is running and a USIM in the terminal device is unchanged, set tl be time remaining for timer timeout at switch off and t be time elapsed between switch off and switch on; and based on determining that the tl is greater than t, restart the at least one backoff timer with a value of tl minus t; based on determining that tl is equal to or less than t, avoid the at least one backoff timer to be restarted; or based on determining that the terminal device is not capable of determining t, restart the at least one backoff timer with the value tl .
[0260] In some embodiments, at least one of: the first sublayer comprises a mobility management (MM) sublayer; the second sublayer comprises a session management (SM) sublayer; the first data comprises first cellular Internet-of-Things (CIoT) user data; the second data comprises second CIoT user data; the session comprises a protocol data unit (PDU) session; and the cause value comprises an MM cause value.
[0261] In some embodiments, an apparatus capable of performing any of the method 500 (for example, the terminal device 110) may comprise means for performing the respective steps of the method 500. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.
[0262] In some embodiments, the apparatus comprises means for receiving, at a first sublayer of the terminal device, a first message comprising first data, an ID of a session, a cause value and a timer value; means for transmitting, from the first sublayer of the terminal device to a second sublayer of the terminal device, the first data, the ID of the session, an indication and the timer value, wherein the indication is based on the cause value and indicates congestion in at least one of a data network identified by a DNN or a network slice identified by a S-NSSAI; and means for performing at least one action for at least one backoff timer based on the indication, the timer value and the ID of the session.
[0263] In some embodiments, the timer value does not indicate that the timer is deactivated. The apparatus further comprises means for performing the at least one action by at least one of: stopping the at least one backoff timer; or if the timer value does not indicate zero, starting the at least one backoff timer with the timer value.
[0264] In some embodiments, the apparatus further comprises means for receiving, at the first sublayer, a second message which comprises second data and the ID of the session and is without any cause value; means for receiving, at the second sublayer from the first sublayer,the second data and the ID of the session; and means for, based on that the at least one backoff timer is running, stopping the at least one backoff timer based on the reception of the second data and the ID of the session.
[0265] In some embodiments, the indication indicates the congestion is in the data network identified by the DNN. The terminal device provided the DNN during establishment of the session. The means for stopping the at least one backoff timer comprise means for stopping a first timer associated with the DNN in the at least one backoff timer, and wherein if the timer value does not indicate zero, the means for starting the at least one backoff timer with the timer value comprise means for starting the first timer associated with the DNN with the timer value.
[0266] In some embodiments, the indication indicates the congestion is in the data network identified by the DNN. The terminal device did not provide any DNN during establishment of the session. The means for stopping the at least one backoff timer comprise means for stopping a first timer associated with no DNN in the at least one backoff timer, and wherein if the timer value does not indicate zero, the means for starting the at least one backoff timer with the timer value comprise means for starting the first timer associated with no DNN with the timer value.
[0267] In some embodiments, the apparatus may further comprise means for keeping the first timer running based on a PLMN change or an inter-system change.
[0268] In some embodiments, the first timer comprises a timer T3396.
[0269] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN. The terminal device provided the DNN and the S-NSSAI during establishment of the session. The means for stopping the at least one backoff timer comprise means for stopping a second timer associated with the DNN and the S-NSSAI in the at least one backoff timer, and wherein if the timer value does not indicate zero, the means for starting the at least one backoff timer with the timer value comprise means for starting the second timer associated with the DNN and the S-NSSAI with the timer value.
[0270] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN. The terminal device provided the DNN and did not provide any S-NSSAI during establishment of the session. The means for stopping the at least one backoff timer comprise means for stopping a secondtimer associated with the DNN and no S-NSSAI in the at least one backoff timer, and wherein if the timer value does not indicate zero, the means for starting the at least one backoff timer with the timer value comprise means for starting the second timer associated with the DNN and no S-NSSAI with the timer value.
[0271] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN. The terminal device provided the S-NSSAI and did not provide any DNN during establishment of the session, the terminal device is caused to stop the at least one backoff timer by: stopping a second timer associated with the S-NSSAI and no DNN in the at least one backoff timer, and wherein if the timer value does not indicate zero, the terminal device is caused to start the at least one backoff timer with the timer value by: starting the second timer associated with the S-NSSAI and no DNN with the timer value.
[0272] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN. The terminal device did not provide any DNN or any S-NSSAI during establishment of the session. The means for stopping the at least one backoff timer comprise means for stopping a second timer associated with no S-NSSAI and no DNN in the at least one backoff timer, and wherein if the timer value does not indicate zero, the means for starting the at least one backoff timer with the timer value comprise means for starting the second timer associated with no DNN and no S-NSSAI with the timer value.
[0273] In some embodiments, the second timer comprises a timer T3584.
[0274] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI. The terminal device provided the S-NSSAI during establishment of the session. The means for stopping the at least one backoff timer comprise means for stopping a third timer associated with the S-NSSAI in at least one backoff timer, and wherein if the timer value does not indicate zero, the means for starting the at least one backoff timer with the timer value comprise means for starting the third timer associated with the S-NSSAI with the timer value.
[0275] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI. The terminal device did not provide any S-NSSAI during establishment of the session. The means for stopping the at least one backoff timer comprise means for stopping a third timer associated with no S-NSSAI in the at least one backoff timer,and wherein if the timer value does not indicate zero, the means for starting the at least one backoff timer with the timer value comprise means for starting the third timer associated with no S-NSSAI with the timer value.
[0276] In some embodiments, the apparatus may further comprise means for keeping the third timer running in case of a PLMN change or an inter-system change.
[0277] In some embodiments, the third timer comprises a timer T3585.
[0278] In some embodiments, the timer value indicates the timer is deactivated. The terminal device comprises means for performing the at least one action by: stopping the at least one backoff timer; and keeping the at least one backoff timer as deactivated.
[0279] In some embodiments, the indication indicates the congestion is in the data network identified by the DNN. The terminal device provided the DNN during establishment of the session. The means for stopping the at least one backoff timer comprise means for stopping a first timer associated with the DNN in the at least one backoff timer, and wherein the means for keeping the at least one backoff timer as deactivated comprise means for keeping the first timer associated with the DNN as deactivated.
[0280] In some embodiments, the indication indicates the congestion is in the data network identified by the DNN. The terminal device did not provide any DNN during establishment of the session. The means for stopping the at least one backoff timer comprise means for stopping a first timer associated with no DNN in the at least one backoff timer, and wherein the means for keeping the at least one backoff timer as deactivated comprise means for keeping the first timer associated with no DNN as deactivated.
[0281] In some embodiments, the apparatus may further comprise means for keeping the first timer as deactivated in case of a PLMN change or an inter-system change.
[0282] In some embodiments, the first timer comprises a timer T3396.
[0283] In some embodiments, the indication indicates the congestion is in the data network identified by the DNN and the network slice identified by the S-NSSAI. The terminal device provided the DNN and the S-NSSAI during establishment of the session. The means for stopping the at least one backoff timer comprise means for stopping a second timer associated with the DNN and the S-NSSAI in the at least one backoff timer, and wherein the means for keeping the at least one backoff timer as deactivated comprise means for keeping the second timer associated with the DNN and the S-NSSAI as deactivated.
[0284] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN. The terminal device provided the DNN and did not provide any S-NSSAI during establishment of the session. The means for stopping the at least one backoff timer comprise means for stopping a second timer associated with the DNN and no S-NSSAI in the at least one backoff timer, and wherein the means for keeping the at least one backoff timer as deactivated comprise means for keeping the second timer associated with the DNN and no S-NSSAI as deactivated.
[0285] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN. The terminal device did not provide any DNN and provided S-NSSAI during establishment of the session. The means for stopping the at least one backoff timer comprise means for stopping a second timer associated with S-NSSAI and no DNN in the at least one backoff timer, and wherein the means for keeping the at least one backoff timer as deactivated comprise means for keeping the second timer associated with the S-NSSAI and no DNN as deactivated.
[0286] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN. The terminal device did not provide any DNN or any S-NSSAI during establishment of the session. The means for stopping the at least one backoff timer comprise means for stopping a second timer associated with no S-NSSAI and no DNN in the at least one backoff timer, and wherein the means for keeping the at least one backoff timer as deactivated comprise means for keeping the second timer associated with no DNN and no S-NSSAI as deactivated.
[0287] In some embodiments, the apparatus may further comprise means for keeping the second timer as deactivated in case of a PLMN change or an inter-system change.
[0288] In some embodiments, the second timer comprises a timer T3584.
[0289] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI. The terminal device provided the S-NSSAI during establishment of the session. The means for stopping the at least one backoff timer comprise means for stopping a third timer associated with the S-NSSAI in at least one backoff timer, and wherein the means for keeping the at least one backoff timer as deactivated comprise means for keeping the third timer associated with the S-NSSAI as deactivated.
[0290] In some embodiments, the indication indicates the congestion is in the network slice identified by the S-NSSAI. The terminal device did not provide any S-NSSAI duringestablishment of the session. The means for stopping the at least one backoff timer comprise means for stopping a third timer associated with no S-NSSAI in the at least one backoff timer, and wherein the means for keeping the at least one backoff timer as deactivated comprise means for keeping the third timer associated with no S-NSSAI as deactivated.
[0291] In some embodiments, the apparatus may further comprise means for keeping the third timer as deactivated in case of a PLMN change or an inter-system change.
[0292] In some embodiments, at least one of: the third timer is applied for a plurality of PLMNs and for a 3GPP access type; the third timer is applied for the plurality of PLMNs and for both the 3GPP access type and a non-3GPP access type; the third timer is applied for a registered PLMN of the plurality of PLMNs and for the 3GPP access type; or the third timer is applied for the registered PLMN of the plurality of PLMNs and for the 3GPP access type and the non-3GPP access type.
[0293] In some embodiments, the third timer comprises a timer T3585.
[0294] In some embodiments, the apparatus may further comprise means for, based on determining that the terminal device is switched off when the at least one backoff timer is running and a USIM in the terminal device is unchanged, setting tl be time remaining for timer timeout at switch off and t be time elapsed between switch off and switch on; and means for, based on determining that the tl is greater than t, restarting the at least one backoff timer with a value of tl minus t; means for, based on determining that tl is equal to or less than t, avoiding the at least one backoff timer to be restarted; or means for, based on determining that the terminal device is not capable of determining t, restarting the at least one backoff timer with the value tl .
[0295] In some embodiments, at least one of: the first sublayer comprises a mobility management (MM) sublayer; the second sublayer comprises a session management (SM) sublayer; the first data comprises first cellular Internet-of-Things (CIoT) user data; the second data comprises second CIoT user data; the session comprises a protocol data unit (PDU) session; and the cause value comprises an MM cause value.
[0296] In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of the method 500. In some embodiments, the means comprises at least one processor and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.
[0297] FIG. 6 illustrates a flowchart of a method 600 implemented at a terminal device according to some embodiments of the present disclosure. For the purpose of discussion, the method 600 will be described from the perspective of the terminal device 110 comprising the SM sublayer (also referred as SM sublayer entity) 110-1 and MM sublayer (also referred as MM sublayer entity) 110-2 with reference to FIG. 1A.
[0298] At block 610, the terminal device 110 may receive, at a MM sublayer 110-2 of the terminal device 110, a first message comprising first CIoT user data, an ID of a PDU session, an MM cause value and a timer value.
[0299] At block 620, the terminal device 110 may transmit, from the MM sublayer 110-2 of the terminal device 110 to a SM sublayer of the terminal device 110, the first CIoT user data, the ID of the PDU session, an indication and the timer value, wherein the indication is based on the MM cause value and indicates congestion in at least one of a data network identified by a DNN or a network slice identified by a S-NSSAI.
[0300] At block 630, the terminal device 110 may start at least one backoff timer based on the indication, the timer value and the ID of the PDU session, wherein the at least one backoff timer comprises at least one of a timer T3396, a timer T3584 and a timer T3585.
[0301] In some embodiments, the timer value indicates neither zero nor the timer is deactivated. The terminal device 110 is caused to start at least one backoff timer by: stopping the at least one backoff timer; and starting the at least one backoff timer with the timer value.
[0302] In some embodiments, the terminal device is further caused to: receive, at the MM sublayer, a second message which comprises second CIoT user data and the ID of the PDU session and is without any MM cause value; receive, at the SM sublayer from the MM sublayer, the second CIoT user data and the ID of the PDU session; and based on that the at least one backoff timer is running, stop the at least one backoff timer based on the reception of the second CIoT user data and the ID of the PDU session.
[0303] In some embodiments, the at least one backoff timer comprises the timer T3396. The indication indicates the congestion is in the data network identified by the DNN. The terminal device provided the DNN during establishment of the PDU session. The terminal device is caused to stop the at least one backoff timer by: stopping the timer T3396 associated with the DNN in the at least one backoff timer, and wherein the terminal device is caused to start the at least one backoff timer with the timer value by: starting the timer T3396 associated with the DNN with the timer value.
[0304] In some embodiments, the at least one backoff timer comprises the timer T3396. The indication indicates the congestion is in the data network identified by the DNN. The terminal device did not provide any DNN during establishment of the PDU session. The terminal device is caused to stop the at least one backoff timer by: stopping the timer T3396 associated with no DNN in the at least one backoff timer, and wherein the terminal device is caused to start the at least one backoff timer with the timer value by: starting the timer T3396 associated with no DNN with the timer value.
[0305] In some embodiments, the terminal device is further caused to: keep the timer T3396 running based on a public land mobile network (PLMN) change or an inter-system change.
[0306] In some embodiments, the at least one backoff timer comprises the timer T3584. The indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN. The terminal device provided the DNN and the S-NSSAI during establishment of the PDU session. The terminal device is caused to stop the at least one backoff timer by: stopping the timer T3584 associated with the DNN and the S-NSSAI in the at least one backoff timer and wherein the terminal device is caused to start the at least one backoff timer with the timer value by: starting the timer T3584 associated with the DNN and the S-NSSAI with the timer value.
[0307] In some embodiments, the at least one backoff timer comprises the timer T3584. The indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN. The terminal device provided the DNN and did not provide any S-NSSAI during establishment of the PDU session. The terminal device is caused to stop the at least one backoff timer by: stopping the timer T3584 associated with the DNN and no S-NSSAI in the at least one backoff timer, and wherein the terminal device is caused to start the at least one backoff timer with the timer value by: starting the timer T3584 associated with the DNN and no S-NSSAI with the timer value.
[0308] In some embodiments, the at least one backoff timer comprises the timer T3584. The indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN. The terminal device provided the S-NSSAI and did not provide any DNN during establishment of the PDU session. The terminal device is caused to stop the at least one backoff timer by: stopping the timer T3584 associated with the S-NSSAI and no DNN in the at least one backoff timer, and wherein the terminal deviceis caused to start the at least one backoff timer with the timer value by: starting the timer T3584 associated with the S-NSSAI and no DNN with the timer value.
[0309] In some embodiments, the at least one backoff timer comprises the timer T3584. The indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN. The terminal device did not provide any DNN or any S-NSSAI during establishment of the PDU session. The terminal device is caused to stop the at least one backoff timer by: stopping the timer T3584 associated with no S-NSSAI and no DNN in the at least one backoff timer and wherein the terminal device is caused to start the at least one backoff timer with the timer value by: starting the timer T3584 associated with no DNN and no S-NSSAI with the timer value.
[0310] In some embodiments, the at least one backoff timer comprises the timer T3585. The indication indicates the congestion is in the network slice identified by the S-NSSAI. The terminal device provided the S-NSSAI during establishment of the PDU session. The terminal device is caused to stop the at least one backoff timer by: stopping the timer T3585 associated with the S-NSSAI in at least one backoff timer, and wherein the terminal device is caused to start the at least one backoff timer with the timer value by: starting the timer T3585 associated with the S-NSSAI with the timer value.
[0311] In some embodiments, the at least one backoff timer comprises the timer T3585. The indication indicates the congestion is in the network slice identified by the S-NSSAI. The terminal device is caused to stop the at least one backoff timer by: stopping the timer T3585 associated with no S-NSSAI in the at least one backoff timer, and wherein the terminal device is caused to start the at least one backoff timer with the timer value by: starting the timer T3585 associated with no S-NSSAI with the timer value.
[0312] In some embodiments, the terminal device is further caused to: keep the timer T3585 running in case of a PLMN change or an inter-system change.
[0313] In some embodiments, wherein at least one of: the timer T3585 is applied for a plurality of PLMNs and for a 3GPP access type; the timer T3585 is applied for the plurality of PLMNs and for both the 3GPP access type and a non-3GPP access type; the T3585 is applied for a registered PLMN of the plurality of PLMNs and for the 3GPP access type; or the timer T3585 is applied for the registered PLMN of the plurality of PLMNs and for the 3 GPP access type and the non-3GPP access type.
[0314] In some embodiments, the terminal device is further caused to: based ondetermining that the terminal device is switched off when the at least one backoff timer is running and a USIM in the terminal device is unchanged, set tl be time remaining for timer timeout at switch off and t be time elapsed between switch off and switch on; and based on determining that the tl is greater than t, restart the at least one backoff timer with a value of tl minus t; based on determining that tl is equal to or less than t, avoid the at least one backoff timer to be restarted; or based on determining that the terminal device is not capable of determining t, restart the at least one backoff timer with the value tl .
[0315] In some embodiments, an apparatus capable of performing any of the method 600 (for example, the terminal device 110) may comprise means for performing the respective steps of the method 600. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.
[0316] In some embodiments, the apparatus comprises means for receiving, at a MM sublayer of the terminal device, a first message comprising first CIoT user data, an ID of a PDU session, an MM cause value and a timer value; means for transmitting, from the MM sublayer of the terminal device to a SM sublayer of the terminal device, the first CIoT user data, the ID of the PDU session, an indication and the timer value, wherein the indication is based on the MM cause value and indicates congestion in at least one of a data network identified by a DNN or a network slice identified by a S-NSSAI; and means for starting at least one backoff timer based on the indication, the timer value and the ID of the PDU session, wherein the at least one backoff timer comprises at least one of a timer T3396, a timer T3584 and a timer T3585.
[0317] In some embodiments, the timer value indicates neither zero nor the timer is deactivated. The means for starting at least one backoff timer comprise means for stopping the at least one backoff timer; and starting the at least one backoff timer with the timer value.
[0318] In some embodiments, the apparatus further comprise means for receiving, at the MM sublayer, a second message which comprises second CIoT user data and the ID of the PDU session and is without any MM cause value; means for receiving, at the SM sublayer from the MM sublayer, the second CIoT user data and the ID of the PDU session; and means for, based on that the at least one backoff timer is running, stopping the at least one backoff timer based on the reception of the second CIoT user data and the ID of the PDU session.
[0319] In some embodiments, the at least one backoff timer comprises the timer T3396. The indication indicates the congestion is in the data network identified by the DNN. Theterminal device provided the DNN during establishment of the PDU session. The means for stopping the at least one backoff timer comprise means for stopping the timer T3396 associated with the DNN in the at least one backoff timer, and wherein the means for starting the at least one backoff timer with the timer value comprise means for starting the timer T3396 associated with the DNN with the timer value.
[0320] In some embodiments, the at least one backoff timer comprises the timer T3396. The indication indicates the congestion is in the data network identified by the DNN. The terminal device did not provide any DNN during establishment of the PDU session. The means for stopping the at least one backoff timer comprise means for stopping the timer T3396 associated with no DNN in the at least one backoff timer, and wherein the means for starting the at least one backoff timer with the timer value comprise means for starting the timer T3396 associated with no DNN with the timer value.
[0321] In some embodiments, the apparatus may comprise means for: keep the timer T3396 running based on a PLMN change or an inter-system change.
[0322] In some embodiments, the at least one backoff timer comprises the timer T3584. The indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN. The terminal device provided the DNN and the S-NSSAI during establishment of the PDU session. The means for stopping the at least one backoff timer comprise means for stopping the timer T3584 associated with the DNN and the S-NSSAI in the at least one backoff timer and wherein the means for starting the at least one backoff timer with the timer value comprise means for starting the timer T3584 associated with the DNN and the S-NSSAI with the timer value.
[0323] In some embodiments, the at least one backoff timer comprises the timer T3584. The indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN. The terminal device provided the DNN and did not provide any S-NSSAI during establishment of the PDU session. The means for stopping the at least one backoff timer comprise means for stopping the timer T3584 associated with the DNN and no S-NSSAI in the at least one backoff timer, and wherein the means for starting the at least one backoff timer with the timer value comprise means for starting the timer T3584 associated with the DNN and no S-NSSAI with the timer value.
[0324] In some embodiments, the at least one backoff timer comprises the timer T3584. The indication indicates the congestion is in the network slice identified by the S-NSSAIand the data network identified by the DNN. The terminal device provided the S-NSSAI and did not provide any DNN during establishment of the PDU session. The means for stopping the at least one backoff timer comprise means for stopping the timer T3584 associated with the S-NSSAI and no DNN in the at least one backoff timer, and wherein the means for starting the at least one backoff timer with the timer value comprise means for starting the timer T3584 associated with the S-NSSAI and no DNN with the timer value.
[0325] In some embodiments, the at least one backoff timer comprises the timer T3584. The indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN. The terminal device did not provide any DNN or any S-NSSAI during establishment of the PDU session. The means for stopping the at least one backoff timer comprise means for stopping the timer T3584 associated with no S-NSSAI and no DNN in the at least one backoff timer and wherein the means for starting the at least one backoff timer with the timer value comprise means for starting the timer T3584 associated with no DNN and no S-NSSAI with the timer value.
[0326] In some embodiments, the at least one backoff timer comprises the timer T3585. The indication indicates the congestion is in the network slice identified by the S-NSSAI. The terminal device provided the S-NSSAI during establishment of the PDU session. The means for stopping the at least one backoff timer comprise means for stopping the timer T3585 associated with the S-NSSAI in at least one backoff timer, and wherein the means for starting the at least one backoff timer with the timer value comprise means for starting the timer T3585 associated with the S-NSSAI with the timer value.
[0327] In some embodiments, the at least one backoff timer comprises the timer T3585. The indication indicates the congestion is in the network slice identified by the S-NSSAI. The means for stopping the at least one backoff timer comprise means for stopping the timer T3585 associated with no S-NSSAI in the at least one backoff timer, and wherein means for starting the at least one backoff timer with the timer value comprise means for starting the timer T3585 associated with no S-NSSAI with the timer value.
[0328] In some embodiments, the apparatus may further comprise means for keeping the timer T3585 running in case of a PLMN change or an inter-system change.
[0329] In some embodiments, wherein at least one of the timer T3585 is applied for a plurality of PLMNs and for a 3GPP access type; the timer T3585 is applied for the plurality of PLMNs and for both the 3GPP access type and a non-3GPP access type; the T3585 isapplied for a registered PLMN of the plurality of PLMNs and for the 3GPP access type; or the timer T3585 is applied for the registered PLMN of the plurality of PLMNs and for the 3 GPP access type and the non-3GPP access type.
[0330] In some embodiments, the apparatus may further comprise means for, based on determining that the terminal device is switched off when the at least one backoff timer is running and a USIM in the terminal device is unchanged, setting tl be time remaining for timer timeout at switch off and t be time elapsed between switch off and switch on; and means for, based on determining that the tl is greater than t, restarting the at least one backoff timer with a value of tl minus t; means for, based on determining that tl is equal to or less than t, avoiding the at least one backoff timer to be restarted; or means for based on determining that the terminal device is not capable of determining t, restarting the at least one backoff timer with the value tl .
[0331] In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of the method 600. In some embodiments, the means comprises at least one processor and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.
[0332] FIG. 7 is a simplified block diagram of a device 700 that is suitable for implementing embodiments of the present disclosure. The device 700 may be provided to implement the communication device, for example the terminal device 110 as shown in FIG.1. As shown, the device 700 includes one or more processors 710, one or more memories 720 coupled to the processor 710, and one or more communication modules 740 coupled to the processor 710.
[0333] The communication module 740 is for bidirectional communications. The communication module 740 has at least one antenna to facilitate communication. The communication interface may represent any interface that is necessary for communication with other network elements.
[0334] The processor 710 may be of any type suitable to the local technical network and may include one or more of the following: general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 700 may have multiple processors, such as an application specific integrated circuit chip that is slaved intime to a clock which synchronizes the main processor.
[0335] The memory 720 may include one or more non-volatile memories and one or more volatile memories. Examples of the non-volatile memories include, but are not limited to, a Read Only Memory (ROM) 724, an electrically programmable read only memory (EPROM), a flash memory, a hard disk, a compact disc (CD), a digital video disk (DVD), and other magnetic storage and / or optical storage. Examples of the volatile memories include, but are not limited to, a random access memory (RAM) 722 and other volatile memories that will not last in the power-down duration.
[0336] A computer program 730 includes computer executable instructions that are executed by the associated processor 710. The program 730 may be stored in the ROM 724. The processor 710 may perform any suitable actions and processing by loading the program 730 into the RAM 722.
[0337] The embodiments of the present disclosure may be implemented by means of the program 730 so that the device 700 may perform any process of the disclosure as discussed with reference to FIGS. 2 to 4. The embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.
[0338] In some embodiments, the program 730 may be tangibly contained in a computer readable medium which may be included in the device 700 (such as in the memory 720) or other storage devices that are accessible by the device 700. The device 700 may load the program 730 from the computer readable medium to the RAM 722 for execution. The computer readable medium may include any types of tangible non-volatile storage, such as ROM, EPROM, a flash memory, a hard disk, CD, DVD, and the like.
[0339] FIG. 8 shows an example of the computer readable medium 800 in form of CD or DVD. The computer readable medium has the program 730 stored thereon.
[0340] Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representations, it is to be understood that the block, apparatus, system, technique or method described herein may be implemented in, as non-limiting examples, hardware, software,firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.
[0341] The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, being executed in a device on a target real or virtual processor, to carry out the method 500 and / or 600 as described above with reference to FIG. 5 and / or 6. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.
[0342] Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the processor or controller, cause the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.
[0343] In the context of the present disclosure, the computer program codes or related data may be carried by any suitable carrier to enable the device, apparatus or processor to perform various processes and operations as described above. Examples of the carrier include a signal, computer readable medium, and the like.
[0344] The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the computer readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory(EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. The term “non-transitory,” as used herein, is a limitation of the medium itself (i.e., tangible, not a signal) as opposed to a limitation on data storage persistency (e.g., RAM vs. ROM).
[0345] Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable sub-combination.
[0346] Although the present disclosure has been described in languages specific to structural features and / or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.
Claims
1. WHAT IS CLAIMED IS:
1. A terminal device comprising:at least one processor; andat least one memory storing instructions that, when executed by the at least one processor, cause the terminal device at least to:receive, at a first sublayer of the terminal device, a first message comprising first data, an identity (ID) of a session, a cause value and a timer value;transmit, from the first sublayer of the terminal device to a second sublayer of the terminal device, the first data, the ID of the session, an indication and the timer value, wherein the indication is based on the cause value and indicates congestion in at least one of a data network identified by a data network name (DNN) or a network slice identified by a single network slice selection assistance information (S-NSSAI); andperform at least one action for at least one backoff timer based on the indication, the timer value and the ID of the session.
2. The terminal device of claim 1, wherein the timer value does not indicate that the timer is deactivated, and wherein the terminal device is caused to perform the at least one action by at least one of:stopping the at least one backoff timer; orif the timer value does not indicate zero, starting the at least one backoff timer with the timer value.3 The terminal device of claim 2, wherein the terminal device is further caused to:receive, at the first sublayer, a second message which comprises second data and the ID of the session and is without any cause value;receive, at the second sublayer from the first sublayer, the second data and the ID of the session; andbased on that the at least one backoff timer is running, stop the at least one backoff timer based on the reception of the second data and the ID of the session.
4. The terminal device of claim 2 or 3, wherein the indication indicates the congestion is in the data network identified by the DNN, the terminal device provided the DNN during establishment of the session, and wherein the terminal device is caused to stop the at least one backoff timer by:stopping a first timer associated with the DNN in the at least one backoff timer, and wherein if the timer value does not indicate zero, the terminal device is caused to start the at least one backoff timer with the timer value by:starting the first timer associated with the DNN with the timer value.
5. The terminal device of claim 2 or 3, wherein the indication indicates the congestion is in the data network identified by the DNN, wherein the terminal device did not provide any DNN during establishment of the session, and wherein the terminal device is caused to stop the at least one backoff timer by:stopping a first timer associated with no DNN in the at least one backoff timer, and wherein if the timer value does not indicate zero, the terminal device is caused to start the at least one backoff timer with the timer value by:starting the first timer associated with no DNN with the timer value.
6. The terminal device of any of claims 2-5, wherein the terminal device is further caused to:keep the first timer running based on a public land mobile network (PLMN) change or an inter-system change.
7. The terminal device of any of claims 2-6, wherein the first timer comprises a timer T3396.
8. The terminal device of claim 2 or 3, wherein the indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN, the terminal device provided the DNN and the S-NSSAI during establishment of the session, and wherein the terminal device is caused to stop the at least one backoff timer by:stopping a second timer associated with the DNN and the S-NSSAI in the at least one backoff timer,and wherein if the timer value does not indicate zero, the terminal device is caused to start the at least one backoff timer with the timer value by:starting the second timer associated with the DNN and the S-NSSAI with the timer value.
9. The terminal device of claim 2 or 3, wherein the indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN, the terminal device provided the DNN and did not provide any S-NSSAI during establishment of the session, and wherein the terminal device is caused to stop the at least one backoff timer by:stopping a second timer associated with the DNN and no S-NSSAI in the at least one backoff timer,and wherein if the timer value does not indicate zero, the terminal device is caused to start the at least one backoff timer with the timer value by:starting the second timer associated with the DNN and no S-NSSAI with the timer value.
10. The terminal device of claim 2 or 3, wherein the indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN, the terminal device provided the S-NSSAI and did not provide any DNN during establishment of the session, and wherein the terminal device is caused to stop the at least one backoff timer by:stopping a second timer associated with the S-NSSAI and no DNN in the at least one backoff timer,and wherein if the timer value does not indicate zero, the terminal device is caused to start the at least one backoff timer with the timer value by:starting the second timer associated with the S-NSSAI and no DNN with the timer value.
11. The terminal device of claim 2 or 3, wherein the indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN, the terminal device did not provide any DNN or any S-NSSAI during establishment of the session, and wherein the terminal device is caused to stop the at leastone backoff timer by:stopping a second timer associated with no S-NSSAI and no DNN in the at least one backoff timer,and wherein if the timer value does not indicate zero, the terminal device is caused to start the at least one backoff timer with the timer value by:starting the second timer associated with no DNN and no S-NSSAI with the timer value.12 The terminal device of any of claims 7 to 11, wherein the second timer comprises a timer T3584.
13. The terminal device of claim 2 or 3, wherein the indication indicates the congestion is in the network slice identified by the S-NSSAI, the terminal device provided the S-NSSAI during establishment of the session, and wherein the terminal device is caused to stop the at least one backoff timer by:stopping a third timer associated with the S-NSSAI in at least one backoff timer, and wherein if the timer value does not indicate zero, the terminal device is caused to start the at least one backoff timer with the timer value by:starting the third timer associated with the S-NSSAI with the timer value.
14. The terminal device of claim 2 or 3, wherein the indication indicates the congestion is in the network slice identified by the S-NSSAI, the terminal device did not provide any S-NSSAI during establishment of the session, and wherein the terminal device is caused to stop the at least one backoff timer by:stopping a third timer associated with no S-NSSAI in the at least one backoff timer, and wherein if the timer value does not indicate zero, the terminal device is caused to start the at least one backoff timer with the timer value by:starting the third timer associated with no S-NSSAI with the timer value.
15. The terminal device of claim 13 or 14, wherein the terminal device is further caused to:keep the third timer running in case of a PLMN change or an inter-system change.16 The terminal device of any of claims 13 to 15, wherein the third timer comprises a timer T3585.
17. The terminal device of claim 1, wherein the timer value indicates the timer is deactivated, and wherein the terminal device is caused to perform the at least one action by:stopping the at least one backoff timer; andkeeping the at least one backoff timer as deactivated.
18. The terminal device of claim 17, wherein the indication indicates the congestion is in the data network identified by the DNN, the terminal device provided the DNN during establishment of the session, and wherein the terminal device is caused to stop the at least one backoff timer by:stopping a first timer associated with the DNN in the at least one backoff timer, and wherein the terminal device is caused to keep the at least one backoff timer as deactivated by:keeping the first timer associated with the DNN as deactivated.
19. The terminal device of claim 17, wherein the indication indicates the congestion is in the data network identified by the DNN, the terminal device did not provide any DNN during establishment of the session, and wherein the terminal device is caused to stop the at least one backoff timer by:stopping a first timer associated with no DNN in the at least one backoff timer, and wherein the terminal device is caused to keep the at least one backoff timer as deactivated by:keeping the first timer associated with no DNN as deactivated.
20. The terminal device of claim 18 or 19, wherein the terminal device is further caused to:keep the first timer as deactivated in case of a PLMN change or an inter-system change.21 The terminal device of any of claims 17-20, wherein the first timer comprises a timer T3396.
22. The terminal device of claim 17, wherein the indication indicates the congestion is in the data network identified by the DNN and the network slice identified by the S-NSSAI, the terminal device provided the DNN and the S-NSSAI during establishment of the session, wherein the terminal device is caused to stop the at least one backoff timer by:stopping a second timer associated with the DNN and the S-NSSAI in the at least one backoff timer,and wherein the terminal device is caused to keep the at least one backoff timer as deactivated by:keeping the second timer associated with the DNN and the S-NSSAI as deactivated.
23. The terminal device of claim 17, wherein the indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN, the terminal device provided the DNN and did not provide any S-NSSAI during establishment of the session, wherein the terminal device is caused to stop the at least one backoff timer by:stopping a second timer associated with the DNN and no S-NSSAI in the at least one backoff timer,and wherein the terminal device is caused to keep the at least one backoff timer as deactivated by:keeping the second timer associated with the DNN and no S-NSSAI as deactivated.
24. The terminal device of claim 17, wherein the indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN, the terminal device did not provide any DNN and provided S-NSSAI during establishment of the session, and wherein the terminal device is caused to stop the at least one backoff timer by:stopping a second timer associated with S-NSSAI and no DNN in the at least one backoff timer,and wherein the terminal device is caused to keep the at least one backoff timer as deactivated by:keeping the second timer associated with the S-NSSAI and no DNN as deactivated.
25. The terminal device of claim 17, wherein the indication indicates the congestion is in the network slice identified by the S-NSSAI and the data network identified by the DNN, the terminal device did not provide any DNN or any S-NSSAI during establishment of the session, and wherein the terminal device is caused to stop the at least one backoff timer by:stopping a second timer associated with no S-NSSAI and no DNN in the at least one backoff timer,and wherein the terminal device is caused to keep the at least one backoff timer as deactivated by:keeping the second timer associated with no DNN and no S-NSSAI as deactivated.
26. The terminal device of any of claims 22-25, wherein the terminal device is further caused to:keep the second timer as deactivated in case of a PLMN change or an inter-system change.27 The terminal device of any of claims 22 to 26, wherein the second timer comprises a timer T3584.
28. The terminal device of claim 17, wherein the indication indicates the congestion is in the network slice identified by the S-NSSAI, the terminal device provided the S-NSSAI during establishment of the session, and wherein the terminal device is caused to stop the at least one backoff timer by:stopping a third timer associated with the S-NSSAI in at least one backoff timer, and wherein the terminal device is caused to keep the at least one backoff timer as deactivated by:keeping the third timer associated with the S-NSSAI as deactivated.
29. The terminal device of claim 17, wherein the indication indicates the congestion is in the network slice identified by the S-NSSAI, the terminal device did not provide any S-NSSAI during establishment of the session, and wherein the terminal device is caused to stop the at least one backoff timer by:stopping a third timer associated with no S-NSSAI in the at least one backoff timer, and wherein the terminal device is caused to keep the at least one backoff timer as deactivated by:keeping the third timer associated with no S-NSSAI as deactivated.
30. The terminal device of claim 28 or 29, wherein the terminal device is further caused to:keep the third timer as deactivated in case of a PLMN change or an inter-system change.
31. The terminal device of any of claims 28-30, wherein at least one of:the third timer is applied for a plurality of PLMNs and for a 3GPP access type; the third timer is applied for the plurality of PLMNs and for both the 3GPP access type and a non-3GPP access type;the third timer is applied for a registered PLMN of the plurality of PLMNs and for the 3 GPP access type; orthe third timer is applied for the registered PLMN of the plurality of PLMNs and for the 3GPP access type and the non-3GPP access type.32 The terminal device of any of claims 28 to 31, wherein the third timer comprises a timer T3585.
33. The terminal device of any of claims 1-32, wherein the terminal device is further caused to:based on determining that the terminal device is switched off when the at least one backoff timer is running and a USIM in the terminal device is unchanged, set tl be time remaining for timer timeout at switch off and t be time elapsed between switch off and switch on; andbased on determining that the tl is greater than t, restart the at least one backoff timer with a value of tl minus t;based on determining that tl is equal to or less than t, avoid the at least one backoff timer to be restarted; orbased on determining that the terminal device is not capable of determining t, restart the at least one backoff timer with the value tl .
34. The terminal device of any of claims 1-33, wherein at least one of:the first sublayer comprises a mobility management (MM) sublayer;the second sublayer comprises a session management (SM) sublayer;the first data comprises first cellular Internet-of-Things (CIoT) user data;the second data comprises second CIoT user data;the session comprises a protocol data unit (PDU) session; andthe cause value comprises an MM cause value.
35. A method comprising:receiving, at a first sublayer of the terminal device, a first message comprising first data, an identity (ID) of a session, a cause value and a timer value;transmitting, from the first sublayer of the terminal device to a second sublayer of the terminal device, the first data, the ID of the session, an indication and the timer value, wherein the indication is based on the cause value and indicates congestion in at least one of a data network identified by a data network name (DNN) or a network slice identified by single network slice selection assistance information (S-NSSAI); andperforming at least one action for at least one backoff timer based on the indication, the timer value and the ID of the session.
36. An apparatus comprising:means for receiving, at a first sublayer of the terminal device, a first message comprising first data, an identity (ID) of a session, a cause value and a timer value;means for transmitting, from the first sublayer of the terminal device to a second sublayer of the terminal device, the first data, the ID of the session, an indication and the timer value, wherein the indication is based on the cause value and indicates congestion in at least one of a data network identified by a data network name (DNN) or a network sliceidentified by single network slice selection assistance information (S-NSSAI); and means for performing at least one action for at least one backoff timer based on the indication, the timer value and the ID of the session.
37. A computer readable medium comprising program instructions that, when executed by an apparatus, cause the apparatus to perform at least the method of claim 35.