Network device and method

Abstract

An exemplary embodiment of the present disclosure relates to a UP transmission for a device in an inactive mode, in which a first network device transmits data received from a terminal device in an inactive mode to a second network device through a connection established between the first network device and the second network device for the terminal device, and transmits a first indication to the second network device indicating termination of data transmission related to the terminal device when a first condition is met. This solution allows the connection established between the first network device and the second network device for the terminal device in an inactive mode to be properly terminated to the second network device.

Description

[Technical Field]

[0001] TECHNICAL FIELD Embodiments of the present disclosure relate generally to the field of telecommunications, and more particularly to methods, apparatus and media for communication. [Background technology]

[0002] In current wireless communication systems, the power consumption of terminal devices is a focus. In order to reduce the power consumption of terminal devices, it has been proposed that terminal devices may be set to several power saving modes (such as inactive mode). For terminal devices in inactive mode, it has been proposed that normal data transmission be suspended. Generally, when a terminal device in inactive mode needs to perform normal communication with a network device, the terminal device must resume connection (i.e., wake up and convert to connected mode).

[0003] To further reduce power consumption, a Third Generation Partnership Project (3GPP) work item has proposed a solution that enables small data transmission (SDT) for terminal devices in inactive mode. By using SDT, a terminal device in inactive mode can remain in inactive mode while enabling uplink (UL) transmission (i.e., UL data). Furthermore, in wireless communication systems, terminal devices typically move over time, which may result in a change of network device serving the terminal device. To date, there are still many issues in such scenarios that need to be discussed and specified. Summary of the Invention [Problem to be solved by the invention]

[0004] In general, the exemplary embodiments of the present disclosure provide a solution for UP transmission (i.e., UL data) for devices in inactive mode. To the extent that any embodiments fall outside the scope of the claims, they should be construed as examples useful for understanding various embodiments of the present disclosure. [Means for solving the problem]

[0005] In a first aspect, a communication method is provided, the method including: transmitting, at a first network device, data received from a terminal device in an inactive mode to a second network device via a connection established for the terminal device between the first network device and a second network device; and, in accordance with determining that a first condition is satisfied, transmitting a first indication to the second network device indicating termination of data transmission associated with the terminal device.

[0006] In a second aspect, a communication method is provided, the method including receiving data from a first network device at a second network device via a connection established for the terminal device between the first and second network devices, the data having been received by the first network device from the terminal device in an inactive mode, the method further including receiving a first indication from the first network device indicating an end of data transmission associated with the terminal device, the first indication being transmitted by the first network device according to a first condition.

[0007] In a third aspect, a communication method is provided, the method including: transmitting, at a first network device, data received from a terminal device in an inactive mode to a second network device via a connection established for the terminal device between the first network device and a second network device; and receiving, from the second network device, a third indication indicating termination of data transmission associated with the terminal device, the third indication being transmitted by the second network device according to a second condition.

[0008] In a fourth aspect, a communication method is provided, the method including receiving data from a first network device at a second network device via a connection established for the terminal device between the first and second network devices, the data received by the first network device from the terminal device in an inactive mode, the method further including, in accordance with determining that a second condition is satisfied, transmitting a third indication to the first network device indicating termination of data transmission associated with the terminal device.

[0009] In a fifth aspect, a communication method is provided, the method including: transmitting, at a first network device, data received from a terminal device in an inactive mode to a second network device via a connection established for the terminal device between the first network device and a second network device; and receiving from the second network device a message for initiating a context relocation procedure, the message being transmitted by the second network device according to a third condition.

[0010] In a sixth aspect, a communication method is provided, the method including receiving, at a second network device, data received by a first network device from a terminal device in an inactive mode from the first network device via a connection established for the terminal device between the first network device and a second network device, the method further including, in accordance with determining that a third condition is met, sending a message to the first network device to initiate a context relocation procedure.

[0011] In a seventh aspect, there is provided a first network device, the first network device including a processor unit and a memory, coupled to the processor unit, having instructions stored thereon, the instructions, when executed by the processor unit, causing the device to perform a method according to the first aspect.

[0012] In an eighth aspect, there is provided a second network device, the second network device including a processor unit and a memory, coupled to the processor unit, having instructions stored thereon, the instructions, when executed by the processor unit, causing the device to perform a method according to the second aspect.

[0013] In a ninth aspect, there is provided a first network device, the first network device including a processor unit and a memory, coupled to the processor unit, having instructions stored thereon, the instructions, when executed by the processor unit, causing the device to perform a method according to the third aspect.

[0014] In a tenth aspect, there is provided a second network device, the second network device including a processor unit and a memory, coupled to the processor unit, having instructions stored thereon, the instructions, when executed by the processor unit, causing the device to perform a method according to the fourth aspect.

[0015] In an eleventh aspect, there is provided a first network device, the first network device including a processor unit and a memory, coupled to the processor unit, having instructions stored thereon, the instructions, when executed by the processor unit, causing the device to perform a method according to the fifth aspect.

[0016] In a twelfth aspect, there is provided a second network device, the second network device including a processor unit and a memory, coupled to the processor unit, having instructions stored thereon, the instructions, when executed by the processor unit, causing the device to perform a method according to the sixth aspect.

[0017] In a thirteenth aspect, there is provided a computer-readable medium having stored thereon instructions which, when executed on at least one processor, cause the at least one processor to perform a method according to the first aspect.

[0018] In a fourteenth aspect, there is provided a computer-readable medium having stored thereon instructions which, when executed on at least one processor, cause the at least one processor to perform a method according to the second aspect.

[0019] In a fifteenth aspect, there is provided a computer-readable medium having stored thereon instructions which, when executed on at least one processor, cause the at least one processor to perform a method according to the third aspect.

[0020] In a sixteenth aspect, there is provided a computer-readable medium having stored thereon instructions which, when executed on at least one processor, cause the at least one processor to perform a method according to the fourth aspect.

[0021] In a seventeenth aspect, there is provided a computer-readable medium having stored thereon instructions which, when executed on at least one processor, cause the at least one processor to perform a method according to the fifth aspect.

[0022] In an eighteenth aspect, there is provided a computer-readable medium having stored thereon instructions which, when executed on at least one processor, cause the at least one processor to perform a method according to the sixth aspect.

[0023] It should be understood that this Summary of the Invention is not intended to identify key features or essential features of the embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will be readily apparent through the following description. [Brief explanation of the drawings]

[0024] The above and other objects, features and advantages of the present disclosure will become more apparent through a more detailed description of several exemplary embodiments of the present disclosure in the accompanying drawings.

[0025] [Figure 1] 1 shows the signaling flow for conventional SDT without the context relocation procedure.

[0026] [Figure 2] 1 illustrates an exemplary communication environment in which exemplary embodiments of the present disclosure may be practiced.

[0027] [Figure 3] 1 is a signaling chart illustrating a process for UL transmission of a terminal device in an inactive mode in accordance with some embodiments of the present disclosure.

[0028] [Figure 4A] 1 is a signaling chart illustrating a process for UL transmission of a terminal device in an inactive mode in accordance with some embodiments of the present disclosure. [Figure 4B] 1 is a signaling chart illustrating a process for UL transmission of a terminal device in an inactive mode in accordance with some embodiments of the present disclosure.

[0029] [Figure 5] 10 is a further signaling chart illustrating a process for UL transmission of a terminal device in an inactive mode in accordance with some embodiments of the present disclosure.

[0030] [Figure 6A] 10 is a further signaling chart illustrating a process for UL transmission of a terminal device in an inactive mode in accordance with some embodiments of the present disclosure. [Figure 6B] 10 is a further signaling chart illustrating a process for UL transmission of a terminal device in an inactive mode in accordance with some embodiments of the present disclosure. [Figure 6C]10 is a further signaling chart illustrating a process for UL transmission of a terminal device in an inactive mode in accordance with some embodiments of the present disclosure.

[0031] [Figure 7] 10 is a further signaling chart illustrating a process for UL transmission of a terminal device in an inactive mode in accordance with some embodiments of the present disclosure.

[0032] [Figure 8A] 10 is a further signaling chart illustrating a process for UL transmission of a terminal device in an inactive mode in accordance with some embodiments of the present disclosure. [Figure 8B] 10 is a further signaling chart illustrating a process for UL transmission of a terminal device in an inactive mode in accordance with some embodiments of the present disclosure.

[0033] [Figure 9] 1 illustrates an exemplary communication method implemented in a first network device, according to some embodiments of the present disclosure.

[0034] [Figure 10] 10 illustrates an exemplary communication method implemented in a second network device, according to some embodiments of the present disclosure.

[0035] [Figure 11] 10 illustrates a further exemplary communication method implemented in a first network device, according to some embodiments of the present disclosure.

[0036] [Figure 12] 10 illustrates a further exemplary communication method implemented in a second network device, according to some embodiments of the present disclosure.

[0037] [Figure 13] 10 illustrates another exemplary communication method implemented in a first network device, according to some embodiments of the present disclosure.

[0038] [Figure 14] 10 illustrates another exemplary communication method implemented in a second network device, according to some embodiments of the present disclosure.

[0039] [Figure 15] 1 shows a schematic block diagram of an apparatus suitable for practicing exemplary embodiments of the present disclosure.

[0040] Throughout the drawings, the same or similar reference numbers represent the same or similar elements. DETAILED DESCRIPTION OF THE INVENTION

[0041] The principles of the present disclosure will be described with reference to several exemplary embodiments. It should be understood that these embodiments are set forth for illustrative purposes only to aid those skilled in the art in understanding and practicing the present disclosure, and are not intended to imply any limitation on the scope of the present disclosure. The embodiments described herein can be implemented in a variety of ways other than those described below.

[0042] In the following description and claims, unless defined otherwise, all technical and scientific terms used have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0043] References in this disclosure to "one embodiment," "embodiment," "exemplary embodiment," etc. indicate that the described embodiment may include a particular feature, structure, or characteristic, but not all embodiments need include such a particular feature, structure, or characteristic. Furthermore, these phrases do not necessarily refer to the same embodiment. Furthermore, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is believed to be within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments, whether or not explicitly described.

[0044] Although terms such as "first," "second," etc. may be used herein to describe various elements, it should be understood that such elements are not limited by these terms. These terms are used only 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 the exemplary embodiments. As used herein, the term "and / or" includes any and all combinations of one or more of the listed items.

[0045] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit example embodiments. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that the terms "comprise," "includes," "have," "having," "includes," and / or "comprising," when used herein, specify the presence of stated features, elements, and / or components, etc., but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof.

[0046] In some instances, values, procedures, or devices are referred to as "optimum," "lowest," "highest," "minimum," "maximum," etc. It is understood that such descriptions are intended to indicate choices among multiple functional alternatives used, and that such choices are not necessarily better, smaller, higher, or more preferred than other choices.

[0047] As used herein, the term "network device" refers to a device capable of providing or hosting a cell or coverage area over which terminal devices can communicate. Examples of network devices include, but are not limited to, a Node B (NB or NB), an Evolved Node B (eNodeB or eNB), a New Radio Access Node B (gNB), a Remote Radio Unit (RRU), a Radio Head (RH), a Remote Radio Head (RRH), a low-power node such as a femto node or a pico node, a satellite network device, an aircraft network device, etc. For purposes of discussion, some exemplary embodiments will be described below with reference to an eNB as an example of a network device.

[0048] As used herein, the term "terminal" refers to any end device capable of wireless communication. By way of example and not limitation, a terminal may also be referred to as a communication device, a user equipment (UE), a subscriber equipment (SS), a portable subscriber equipment, a mobile station (MS), or an access terminal (AT). Terminal devices include, but are not limited to, mobile phones, mobile phones, smartphones, Voice over IP (VoIP) phones, wireless local loop phones, tablets, wearable terminal devices, personal digital assistants (PDAs), portable computers, desktop computers, imaging terminal devices such as digital cameras, gaming terminal devices, music storage and playback devices, in-vehicle wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), USB dongles, smart devices, wireless customer premises equipment (CPE), Internet of Things (IoT) devices, wearables such as watches, head-mounted displays (HMD), vehicles, drones, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in industrial and / or automated processing chain environments), consumer electronics devices, devices operating in commercial and / or industrial wireless networks, etc. In the following description, the terms "terminal device," "communications device," "terminal," "user equipment," and "UE" may be used interchangeably.

[0049] As used herein, the term "communication network" refers to a network conforming to any suitable communication standard, such as New Radio (NR), Long Term Evolution (LTE), LTE-Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA), High-Speed ​​Packet Access (HSPA), Narrow Band Internet of Things (NB-IoT), etc. Furthermore, communications between terminal devices and network devices in a communication network may be performed by any suitable generation of communication protocols, including, but not limited to, first generation (1G), second generation (2G), 2.5G, 2.75G, third generation (3G), fourth generation (4G), 4.5G, fifth generation (5G) communication protocols, and / or other protocols now known or developed in the future. Embodiments of the present disclosure may be applied to various communication systems. Considering the rapid development of communications, there will naturally be future communications technologies and systems in which the present disclosure can be embodied, and the scope of the present disclosure should not be deemed to be limited to only the aforementioned systems.

[0050] As used herein, the term "core device" refers to any device or entity that provides an Access and Mobility Management Function (AMF), a Session Management Function (SMF), a User Plane Function (UPF), etc. By way of example and not limitation, the core device may be an AMF, an SMF, a UPF, etc. In other embodiments, the core device may be any other suitable device or entity.

[0051] As used herein, the term "end marker" means one message between two ends / devices / elements of the user plane of an interface, such as Iu, Gn, Gp, S1-U, S11-U, S2a, S2b, S4, S5, S8, S12, X2, M1, Sn, Xn, N3, and N9. By way of example and not limitation, the end marker may be a GPT-U (GPRS Tunnel Protocol-user plane) end marker.

[0052] As used herein, the terms "UL Transmission," "SDT," and "UL Data" are equivalent to each other.

[0053] As used herein, the term "circuitry" may refer to a hardware circuit and / or a combination of a hardware circuit and software. For example, a circuit may be a combination of analog and / or digital hardware circuitry and software / firmware. As a further example, a circuit may be any portion of a hardware processor with software, such as a digital signal processor, software, and memory that cooperate to perform various functions in a device, such as a terminal device or network device. In yet another example, a circuit may be a hardware circuit and / or processor, such as a microprocessor or portion of a microprocessor, that requires software / firmware for operation but may be absent when not required for operation. As used herein, the term circuitry also encompasses a simple hardware circuit or processor, or portion of a hardware circuit or processor, and its (or their) accompanying software and / or firmware implementation.

[0054] While the functions described herein may be performed in fixed and / or wireless network nodes in various exemplary embodiments, in other exemplary embodiments, the functions may be implemented in a user terminal device (such as a mobile phone, tablet computer, laptop computer, desktop computer, mobile IoT device, or fixed IoT device). Such a user terminal device may include corresponding functions, as appropriate, such as those described in connection with the fixed and / or wireless network nodes. The user terminal device may be a user terminal and / or a control device, such as a chipset or processor, configured to control the user terminal when attached to the user terminal. Examples of such functions include a bootstrap server function and / or a home subscriber server. Such functions may be implemented in the user terminal device by providing the user terminal device with software configured for execution by the user terminal device in terms of these functions / nodes.

[0055] As described above, in order to reduce the power consumption of a terminal device in wireless communication, several power saving modes may be set in the terminal device. For example, a 3GPP work item has proposed and defined a radio resource control (RRC) inactive mode. Also, as described above, in order to further reduce power consumption, a 3GPP work item has proposed a solution enabling SDT of a terminal device in the RRC inactive mode. In this way, a terminal device in the inactive RRC mode may remain in the inactive RRC mode while enabling data transmission. One proposed solution for enabling SDT is performed by using a random access channel (RACH) procedure (also referred to as a RACH-based scheme) including a two-step RACH and a four-step RACH. More specifically, SDT may be transmitted by a terminal device in the inactive mode to a network device via message A of the two-step RACH and message 3 of the four-step RACH.

[0056] Examples of application scenarios of SDT for smart terminal devices include, but are not limited to: Traffic / data / packets from instant messaging services (e.g., WhatsApp, QQ, WeChat, MSN, etc.) Heartbeat / keep-alive traffic / data / packets from some applications (e.g. instant applications, email applications, etc.) Push notifications from various applications

[0057] Examples of application scenarios of SDT for non-smart terminal devices include, but are not limited to: Traffic / data / packets from wearables (e.g., periodic location information, reference signals, etc.) Periodic or non-periodic traffic / data / packets from sensors (e.g., temperature samples, pressure samples, and parameters from industrial wireless sensor networks) Periodic meter readings from smart meter devices and smart meter network equipment

[0058] Also, for SDT, Uplink / Downlink (UL / DL) transmissions following UL SDT (hereinafter also referred to as subsequent transmissions) without transitioning to RRC connected mode may be supported. Furthermore, when the terminal device is in RRC inactive mode, the terminal device may be able to transmit multiple UL and DL packets as part of the same SDT mechanism without transitioning to RRC connected mode with a dedicated grant.

[0059] In addition to the above, as discussed in wireless communication systems, terminals typically move over time, which may result in changes in the network device serving the terminal device. The RACH-based scheme for SDT may be supported both with and without a context relocation procedure. Figure 1 shows a conventional signaling flow 100 for SDT without a context relocation procedure, which is proposed to perform SDT transmission without content relocation.

[0060] In the embodiment described with reference to FIG. 1, the term “last serving network device” refers to a network device that holds the context of the terminal device, where the context may be used to generate an RRC release message for the terminal device 230 or to initiate a context relocation procedure for the terminal device 230, and the term “new network device” refers to a network device of the cell on which the terminal device 230 is camped.

[0061] As shown in FIG. 1, the terminal device is currently in RRC inactive mode and needs to transmit UL data to the network device. The terminal device sends an RRC resumption request to the new network device (e.g., in message A of the two-step RACH or message 3 of the four-step RACH) (110). Furthermore, UL data is transmitted to the first network device 220-1 along with the RRC resumption request. The new network device sends a Retrieve UE Context Request to the last serving network device (120), and the last serving network device responds with a Retrieve UE Context Response (130). Here, the Retrieve UE Context Response may carry part of the terminal device's context. The new network device then sends the UL data to the last serving network device (140), and the last serving network device sends UP data to the AMF (150). The new network device may then send an RRC release message to the terminal device (160).

[0062] From the above, it can be seen that the proposed signaling flow only discusses a method for transmitting a one-shot SDT. Furthermore, the proposed signaling flow does not discuss a method for terminating the connection between the new network device and the last serving network device. As described above, UL / DL transmission (i.e., UL / DL data) following UL data (i.e., subsequent UL / DL transmission) should be supported. Therefore, for subsequent DL transmissions, because the connection between the new network device and the last serving network device has not been terminated, the last serving network device may forward the subsequent DL data to the new network device, which may cause confusion about how to process the subsequent DL data. For subsequent UL data, because the connection between the new network device and the last serving network device has not been terminated, the new network device may continue to transmit the subsequent UL data to the last serving network device. However, if there are many UL transmissions, the subsequent UL transmissions may be a burden on the last serving network device.

[0063] Therefore, there are still issues to be considered and defined. In particular, it is desirable to propose and discuss how to terminate the connection between the new network device and the last serving network device, and how to handle UE content when there are many subsequent transmissions (i.e., UL / DL data) for a terminal device in an inactive mode (e.g., RRC inactive mode).

[0064] According to some exemplary embodiments of the present disclosure, a solution for UP transmission of a terminal device in an inactive mode is proposed. In this solution, a first network device (e.g., a new network device) and a second network device (e.g., a last serving network device) may terminate the connection between the first network device and the network device according to their respective termination conditions. In this way, the connection between the first network device and the network device is properly terminated, so that subsequent DL data is not transmitted to the first network device. Furthermore, the first network device may also determine whether to initiate a context relocation procedure for the terminal device during the UP transmission procedure (including the subsequent UP data) according to a third condition. In this way, the second network device may dynamically and timely determine whether to initiate a context relocation procedure when subsequent transmissions (including subsequent UL data and DL data) will burden the second network device.

[0065] Example Environment FIG. 2 illustrates an example communications network 200 in which example embodiments of the present disclosure may be implemented.

[0066] In the communication environment 200, one or more network devices 220-1 and 220-2 (collectively referred to as network devices 220) can communicate with a core device 210 (e.g., UFP, AMF, etc.). The one or more network devices 220-1 and 220-2 can provide service to terminal devices 230, and the serving areas of the network devices 220-1 and 220-2 are referred to as cells 202-1 and 202-2 (collectively or individually referred to as cells 202). For purposes of discussion, the network device 220-1 will be referred to as the first network device 220-1, and the network device 220-2 will be referred to as the second network device 220-2. Furthermore, the first network device 202-1 and the second network device 220-2 can communicate with each other.

[0067] In environment 100, a link from first network device 202-1 or second network device 220-2 to terminal device 230 is referred to as DL, while a link from terminal device 2300 to first network device 202-1 or second network device 220-2 is referred to as UL. In DL, first network device 202-1 or second network device 220-2 is a TX device (or transmitter) and terminal device 230 is an RX device (or receiver). In UP, terminal device 230 is a transmitting (TX) device (or transmitter) and first network device 202-1 or second network device 220-2 is a receiving (RX) device (or receiver).

[0068] Additionally, in the example of FIG. 2, terminal device 230 may move over time. As shown in FIG. 2, terminal device 230 may be located in different locations over time. Furthermore, terminal device 230 may be in different modes, such as connected mode and inactive mode. In the specific example of FIG. 2, second network device 220-2 (sometimes referred to as the "last serving network device" or "anchor network device") maintains the terminal device's context. Furthermore, terminal device 230 is in an inactive mode and is camped on first network device 220-1 (sometimes referred to as the "new network device").

[0069] Communications in network 100 may conform to any suitable standard, including, but not limited to, Long Term Evolution (LTE), LTE Evolution (LTE-Evolution), LTE Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA), Code Division Multiple Access (CDMA), and Global System for Mobile Communications (GSM). Furthermore, communications may be performed according to any currently known or future-developed generation of communications protocols. Examples of communications protocols include, but are not limited to, first-generation (1G), second-generation (2G), 2.5G, 2.75G, third-generation (3G), fourth-generation (4G), 4.5G, and fifth-generation (5G) communications protocols.

[0070] It should be understood that the number of first network devices, second network devices, core devices, terminal devices, and cell connections is for illustrative purposes only and does not imply any limitation. Communications environment 100 may include any suitable first network devices, second network devices, core devices, terminal devices, and cells suitable for implementing embodiments of the present disclosure. Although not shown, it should be understood that one or more additional first network devices and second network devices may be located within each cell 202. It should also be understood that in some examples, environment 200 may include only homogeneous network deployments or only heterogeneous network deployments.

[0071] Exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. More specifically, Figures 3 and 4A illustrate a process in which a first network device 220-1 initiates a connection termination between the first network device 220-1 and the second network device 220-2. Figures 5 and 6A-6C illustrate a process in which a second network device 220-2 initiates a connection termination between the first network device 220-1 and the second network device 220-2. Figures 7, 8A, and 8B illustrate a process in which a second network device 220-2 initiates a content relocation procedure for a terminal device during a UP transmission.

[0072] It should be noted that although the following description describes operations in a particular order, it should not be understood that performing these operations in the particular order or sequence shown, or performing all of the operations shown, is required to achieve desired results. In some situations, multitasking and parallel processing may be advantageous. Similarly, while the above discussion includes several specific implementation details, these should not be construed as limitations on the scope of the disclosure, but rather as descriptions of features that may be specific to particular embodiments. Some features that are described in the context of individual embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable subcombination.

[0073] Exemplary Process for First Network Device Initiating Connection Termination Reference is now made to Figure 3, which illustrates a signaling flow 300 for UL transmission (i.e., UL data) of a terminal device in an inactive mode, in accordance with some embodiments of the present disclosure. For purposes of discussion, signaling flow 300 will be described with reference to Figure 2. Signaling flow 300 may involve first network device 220-1, second network device 220-2, and terminal device 230.

[0074] 3, the first network device 220-1 receives UL data from the terminal device 230, and then transmits the UL data (315) over the connection established for the terminal device 230 between the first network device 220-1 and the second network device 220-2. The UL data may be one-shot UL data or subsequent UL data. More specifically, the first network device 220-2 may first transmit additional UL data (305) to the second network device 220-2, and then subsequently transmit the UL data to the second network device 220-2 (315).

[0075] During operation, if the first network device 220-1 determines that a first condition is met, the first network device 220-1 may transmit (320) a first indication indicating termination of data transmission associated with terminal device 230. As a result, a connection (e.g., a GPT-U tunnel) established for terminal device 230 between the first network device 220-1 and the second network device 220-2 may thereby be terminated. The first condition is used by the first network device to determine whether to terminate data transmission associated with terminal device 230. In one embodiment, the first indication indicates termination of transmissions in an inactive mode. The transmissions may include at least one of UL transmissions and DL transmissions.

[0076] In some exemplary embodiments, termination of data transmission refers to the termination of a data transmission procedure (such as SDT or other UL / DL transmission procedure) associated with a terminal device in active mode. Alternatively, or additionally, in some exemplary embodiments, termination of data transmission refers to the termination of a current transmission procedure (such as SDT or other UL / DL transmission procedure). Alternatively, or additionally, in some exemplary embodiments, termination of a data connection may be performed by releasing associated protocol stacks and configurations. It should be understood that the above-described methods for performing termination of data transmission are for illustrative purposes only and do not imply any limitations. In other embodiments, any suitable method may be used to terminate data transmission associated with terminal device 230.

[0077] Then, after receiving the first instruction, the second network device 220-2 may process the connection, such as disconnecting the connection between the first network device 220-1 and the second network device 220-2, releasing related protocol stacks and settings, terminating related transmissions (e.g., SDT), stopping forwarding of DL data to the first network device 220-1, etc. Meanwhile, the first network device 220-1 may send an RRC release message to the terminal device 230 (325).

[0078] In this way, the second network device 220-2 can be informed that the connection between the first network device 220-1 and the second network device 220-2 has been terminated, so that when the second network device 220-2 receives DL data for the terminal device, the second network device 220-2 will no longer forward the DL data to the first network device 220-1. Instead, the second network device 220-2 may initiate a paging procedure for the terminal device 230, and the DL data may then be sent to the terminal device 230 accordingly.

[0079] In some exemplary embodiments, the first indication may be transmitted via signaling transmitted over the Xn or X2 interface, or alternatively, the first indication may be transmitted via at least one end marker packet.

[0080] It should be understood that the above-described signaling or packets for transmitting the first instruction are for illustrative purposes only and do not imply any limitation. In other exemplary embodiments, any suitable message or signaling may be used to transmit the first instruction. In this manner, the first instruction may be flexibly transmitted to the second network device 220-2.

[0081] In some exemplary embodiments, the first network device 220-1 determines that the first condition is met when the first network device 220-1 receives 310 data from the terminal device 230 and the data does not include information regarding the amount of data to be transmitted by the terminal device 230. For example, the first network device 220-1 receives data without a buffer status report (BSR). Alternatively, in some exemplary embodiments, the first network device 220-1 determines that the first condition is met when the first network device 220-1 receives 310 data from the terminal device 230 and the data includes a second indication indicating that there is no more data to be transmitted by the terminal device 230. For example, the first network device 220-1 receives data carrying a BSR value of 0. Also, in some exemplary embodiments, the data may be transmitted via an RRC resumption message (such as message A of a two-step RACH or message 3 of a four-step RACH). Alternatively, in some exemplary embodiments, the data is transmitted via the granted UL resources.

[0082] In this manner, the first network device 220-1 may more gracefully terminate the connection between the first network device 220-1 and the second network device 220-2.

[0083] To better illustrate the above process, some specific examples are provided below, which are for illustrative purposes only and do not imply any limitation.

[0084] An example of a one-shot UL transmission scenario will be described with reference to FIG. 4A. FIG. 4A illustrates a signaling flow 400 for a one-shot UL transmission of a terminal device 230 in an inactive mode, in accordance with some embodiments of the present disclosure. For purposes of discussion, the signaling flow 400 will be described with reference to FIG. 2. The signaling flow 400 may involve a core device 210 (e.g., a UPF), a first network device 220-1, a second network device 220-2, and a terminal device 230.

[0085] During operation, the terminal device 405 sends (405) an RRC resumption request (e.g., message A of a two-step RACH or message 3 of a four-step RACH) to the first network device 220-1, and the RRC resumption request is sent. Furthermore, UL data is sent to the first network device 220-1. Furthermore, information about the amount of data to be transmitted by the terminal device (e.g., BSR) is not indicated. In other words, neither the message nor the data sent by the terminal device 230 includes information about the amount of data to be transmitted by the terminal device (e.g., BSR). The first network device 220-1 may then determine that there is no more data to be transmitted by the terminal device 230. This means that after transmitting the UL data, the first network device 220-1 may terminate the connection between the first network device 220-1 and the second network device 220-2. For example, the first network device may decide to terminate the UP transmission procedure (e.g., SDT), release related protocol stacks and settings, etc.

[0086] The first network device 220-1 sends (410) a Retrieve UE Context Request to the second network device 220-2, where the Retrieve UE Context Request carries a BSR value of 0, indicating that there is no more data to send related to the terminal device 230. The second network device 220-2 responds (415) with a Retrieve UE Context Response / Failure, where the Retrieve UE Context Response / Failure carries an RRC release message for the terminal device 230.

[0087] Thereafter, the first network device 220-1 transmits the UL data to the second network device 220-2 (420), and the second network device 220-2 transmits the UL data to the core device 210 (425). Also, in the specific example of Figure 4A, the second network device 220-2 receives DL data for the terminal device 230 from the core device 210 (430), and the second network device 220-2 transmits the DL data to the first network device 220-1 (435).

[0088] The first network device 220-1 then transmits (440) a first indication indicating the end of data transmission related to the terminal device 230 to the second network device 220-2 via Xn / N2 signaling or at least one end marker packet. Meanwhile, the first network device 220-1 transmits (445) an RRC release message to the terminal device 230. Furthermore, DL data for the terminal device 230 is transmitted to the terminal device 230 together with or separately from the RRC release message.

[0089] After describing the one-shot UL transmission scenario, an example of an UP transmission scenario including a subsequent UL transmission will be described with reference to FIG. 4B.

[0090] Reference is now made to Figure 4B, which illustrates a signaling flow 450 for a scenario of an UP transmission including a subsequent UL transmission. For purposes of discussion, the signaling flow 450 will be described with reference to Figure 2. The signaling flow 450 may involve a core device 210 (e.g., a UPF), a first network device 220-1, a second network device 220-2, and a terminal device 230.

[0091] During operation, the terminal device 230 sends an RRC resumption request (e.g., message A of a two-step RACH or message 3 of a four-step RACH) to the second network device 220-2 (450). In addition, UL data is transmitted to the first network device 220-1. In addition, information that there is still more UP data to be transmitted by the terminal device 230 may be indicated to the first network device 220-1. For example, the terminal device 230 transmits a non-zero BSR to the first network device 220-1.

[0092] According to the UL data, the first network device 220-1 may determine that there is still data to be transmitted by the terminal device 230 in addition to the data included in the RRC resumption request, which means that the connection between the first network device 220-1 and the second network device 220-2 should not be terminated.

[0093] The first network device 220-1 sends a Retrieve UE Context Request to the second network device 220-2 (452). The second network device 220-2 responds with a Retrieve UE Context Response / Failure (454) indicating that the UE context will not be relocated, and optionally, the Retrieve UE Context Response / Failure carries an RRC release message for the terminal device 230.

[0094] Thereafter, the first network device 220-1 transmits the UL data to the second network device 220-2 (456), and the second network device 220-2 transmits the UL data to the core device 210 (458). Also, in the example of Figure 4B, the second network device 220-2 receives DL data for the terminal device 230 from the core device 210 (460), and the second network device 220-2 transmits the DL data to the first network device 220-1 (462).

[0095] As described above, the first network device 220-1 knows that there is more data to be transmitted by the terminal device 230. Therefore, the first network device 220-1 transmits (464) a contention resolution message to the terminal device 230. The message optionally carries an indication of further UP data and optionally carries an UL grant for the further UP data. Additionally, optional DL data may also be transmitted to the terminal device 230.

[0096] After receiving the UL grant, terminal device 230 transmits subsequent UL data to second network device 220-2 (466). In this example of FIG. 4B, terminal device 230 also has further subsequent UL data to be transmitted after transmitting the subsequent UL data. Thus, the subsequent UL data includes a non-zero BSR. Based on the subsequent UL data, first network device 220-1 may determine that there is still further subsequent UL data to be transmitted by terminal device 230.

[0097] Next, the first network device 220-1 transmits (468) the subsequent UL data to the second network device 220-2, which then transmits (470) the subsequent UL data to the core device 210. Also in the example of Figure 4B, the second network device 220-2 receives (472) further DL data for the terminal device 230 from the core device 210, and the second network device 220-2 transmits (474) the further DL data to the first network device 220-1.

[0098] As described above, the first network device 220-1 knows that there is still more subsequent data to be transmitted by the terminal device 230. Therefore, the first network device 220-1 transmits 476 an additional UL grant for the additional subsequent UP data. More specifically, in the example of FIG. 4B, the UL grant is transmitted along with the additional DL data.

[0099] Terminal device 230 may then transmit further subsequent UL data to first network device 220-1 via a further UL grant (478). In the example of FIG. 4B, the further subsequent UL data does not include information (such as a BSR) regarding the amount of data to be transmitted by terminal device 230. According to the further subsequent UL data, first network device 220-1 may determine that there is no more data to be transmitted by terminal device 230. This means that after transmitting the further subsequent UL data, first network device 220-1 may terminate the connection between first network device 220-1 and second network device 220-2.

[0100] The first network device 220-1 transmits (480) further subsequent UL data to the second network device 220-2, which transmits (482) further subsequent UL data to the core device 210. Also, in the example of Figure 4B, the second network device 220-2 receives (484) further DL data for the terminal device 230 from the core device 210, and the second network device 220-2 transmits (486) further DL data to the first network device 220-1.

[0101] Next, the first network device 220-1 transmits a first indication indicating the end of data transmission related to the terminal device 230 to the second network device 220-2 via Xn / N2 signaling or at least one end marker packet (488). The second network device 220-1 may also transmit information to the first network device 220-1 for releasing the RRC connection of the terminal device 230. The information may be transmitted via signaling transmitted on the Xn or X2 interface. Meanwhile, the first network device 220-1 transmits an RRC release message to the terminal device 230 (490). Further, other DL data is transmitted to the terminal device 230.

[0102] The above discussion fully discusses the process by which the first network device 220-1 initiates the termination of a connection between the first network device 220-1 and the second network device 220-2.

[0103] Exemplary Process for Second Network Device Initiating Connection Termination Reference is now made to Figure 5, which illustrates a signaling flow 500 for UL transmissions of a terminal device in an inactive mode, in accordance with some embodiments of the present disclosure. For purposes of discussion, signaling flow 500 will be described with reference to Figure 2. Signaling flow 500 may involve first network device 220-1, second network device 220-2, and terminal device 230.

[0104] The signaling flow 500 shown in Figure 5 is similar to the signaling flow 300 shown in Figure 3, and the same operations / elements are given the same reference numerals. For the sake of brevity, the description of the same operations / elements will be omitted below.

[0105] 5, if the second network device 220-2 determines that the second condition is met, the second network device 220-2 may send (520) a third indication to the second network device 220-2 indicating termination of data transmission associated with terminal device 230. As a result, the connection (e.g., the GPT-U tunnel) established for terminal device 230 between the first network device 220-1 and the second network device 220-2 may thereby be terminated. The first network device 220-1 may then be notified that the connection between the first network device 220-1 and the second network device 220-2 has been terminated. The second condition is used by the second network device to determine whether to terminate data transmission associated with terminal device 230.

[0106] In this way, the second network device 220-2 may decide whether to terminate the connection. Therefore, when the second network device 220-2 receives DL data for the terminal device 230, the second network device 220-2 can decide whether to forward the DL data to the first network device 220-1 and whether to initiate a paging procedure for the terminal device 230.

[0107] In some exemplary embodiments, termination of data transmission refers to the termination of a data transmission procedure (such as SDT or other UL / DL transmission procedure) associated with a terminal device in active mode. Alternatively, or additionally, in some exemplary embodiments, termination of data transmission refers to the termination of a current transmission procedure (such as SDT or other UL / DL transmission procedure). Alternatively, or additionally, in some exemplary embodiments, termination of a data connection may be implemented by releasing associated protocol stacks and configurations and ceasing forwarding of DL data to network device 220-1. It should be understood that the methods described above for implementing termination of data transmission are for illustrative purposes only and do not imply any limitations. In other embodiments, any suitable method may be used to terminate data transmission associated with terminal device 230.

[0108] In some exemplary embodiments, the third indication may be transmitted via signaling transmitted over the Xn or X2 interface, or alternatively, the third indication may be transmitted via at least one end marker packet.

[0109] It should be understood that the above-described signaling or packets for transmitting the third instruction are for illustrative purposes only and do not imply any limitation. In other exemplary embodiments, any suitable message or signaling may be used to transmit the third instruction. In this manner, the third instruction may be flexibly transmitted to the second network device 220-2.

[0110] In some demonstrative embodiments, second network device 220-2 may transmit, together with the third instruction, information for releasing the RRC connection of terminal device 230. For example, the RRC release message of terminal device 230 may be embedded in signaling transmitted over the Xn or X2 interface for transmitting the third instruction. In this manner, first network device 220-1 may obtain the information for releasing the RRC connection of terminal device 230 without additional overhead.

[0111] Also, in some exemplary embodiments, if the second network device 220-2 receives a fourth instruction from the first network device 220-1, and the fourth instruction indicates that no more data associated with the terminal device is to be transmitted, the second network device 220-2 determines that the second condition is met and therefore transmits a third instruction to the first network device 220-2. In this manner, the second network device 220-2 may more appropriately initiate connection termination.

[0112] In some exemplary embodiments, the fourth indication may be transmitted via signaling transmitted over the Xn or X2 interface. Alternatively, the fourth indication may be transmitted via at least one end marker packet. Alternatively, the fourth indication may be transmitted via a header of data transmitted from the first network device 220-1 to the second network device 220-2. For example, the "RAN Container" GTP-U extension header of the GTP-U protocol may be used as the fourth indication to indicate buffer size information (such as BSR).

[0113] It should be understood that the above-described signaling or packets for transmitting the fourth instruction are for illustrative purposes only and do not imply any limitation. In other exemplary embodiments, any suitable message or signaling may be used to transmit the fourth instruction. In this manner, the fourth instruction may be flexibly transmitted to the second network device 220-2.

[0114] Alternatively, or additionally, the second network device 220-2 may determine that the second condition is met and therefore send the third indication if the second network device determines that there is no more DL data to send for the terminal device 230. In this manner, DL data may be sent to the terminal device without initiating a paging procedure.

[0115] Alternatively, or in addition, if the second network device does not receive any further UL data from the first network device 210-1 for a certain period of time, the second network device 202-2 may determine that the second condition is met and therefore send a third instruction to the first network device 220-1. Thus, the second network device 220-2 may determine whether to connect according to the status of the UL transmission.

[0116] It should be appreciated that the second network device may determine whether the second condition is met according to any suitable criteria or combination thereof. In this manner, the second network device 220-2 may more appropriately terminate the connection between the first network device 220-1 and the second network device 220-2.

[0117] To better illustrate the above process, some specific examples are provided below, which are for illustrative purposes only and do not imply any limitation.

[0118] An example of a one-shot UL transmission scenario will be described first with reference to FIG. 6A. FIG. 6A illustrates a signaling flow 600 for a one-shot UL transmission of a terminal device in an inactive mode, according to some embodiments of the present disclosure. For discussion purposes, the signaling flow 600 will be described with reference to FIG. 2. The signaling flow 600 may involve a core device 210 (e.g., a UPF), a first network device 220-1, a second network device 220-2, and a terminal device 230.

[0119] The signaling flow 600 shown in Figure 6A is similar to the signaling flow 400 shown in Figure 4A, and the same operations / elements are given the same reference numerals. For the sake of brevity, the description of the same operations / elements will be omitted below.

[0120] In the example of Figure 6A, if the second network device 220-2 determines that the second condition is met, the second network device 220-2 may send an Xn message (carrying a third instruction) to the first network device 220-1 to terminate the connection between the first network device 220-1 and the second network device 220-2 (605). Further, in the example of Figure 6A, the Xn message may carry information for releasing the terminal device's RRC connection. Alternatively, the third instruction is sent via at least one end marker packet.

[0121] Furthermore, as described above, the first network device 220-1 sends a Retrieve UE Context Request to the second network device 220-2 (410), where the Retrieve UE Context Request carries a BSR value of 0, indicating that there is no more data to transmit related to the terminal device 230. Therefore, the BSR included in the Retrieve UE Context Request may be considered as a fourth indication.

[0122] Throughout the above description, a process for a one-shot scenario has been discussed in accordance with some embodiments of the present disclosure. Next, a specific example of a UP transmission scenario with a subsequent UL transmission will be described with reference to Figures 6B and 6C.

[0123] 6B and 6C illustrate signaling flows 640, 660, respectively, for an UL transmission including subsequent UL data, in accordance with some embodiments of the present disclosure. For purposes of discussion, the signaling flows 640, 660 will be described with reference to FIG. 2. The signaling flows 640, 660 may involve the core device 210 (e.g., the UPF), the first network device 220-1, the second network device 220-2, and the terminal device 230.

[0124] The signaling flows 640, 660 shown in Figures 6B, 6B are similar to the signaling flow 450 shown in Figure 4B, and the same operations / elements are given the same reference numerals. For the sake of brevity, the description of the same operations / elements will be omitted below.

[0125] Referring now to the example of FIG. 6B, first, reference is made to FIG. 6B. In the specific example of FIG. 6B, the first network device 220-1 transmits a fourth indication to the second network device 220-2 (642). Here, the fourth indication indicates that there is no more data to be transmitted related to the terminal device 230. The fourth indication may be transmitted via signaling transmitted over the Xn or X2 interface. Alternatively, the fourth indication may be transmitted via at least one end marker packet. Alternatively, the fourth indication may be transmitted via a header of data transmitted from the first network device 220-1 to the second network device 220-2. For example, the "RAN Container" GTP-U extension header of the GTP-U protocol may be used as the fourth indication to indicate buffer size information (such as BSR).

[0126] If the second network device 220-2 determines that the second condition is met, the second network device 220-2 may send an Xn message (carrying a third instruction) to the first network device 220-1 to terminate the connection between the first network device 220-1 and the second network device 220-2 (644). Further, in the example of FIG. 6B, the Xn message may carry information for releasing the terminal device's RRC connection. Alternatively, the third instruction is sent via at least one end marker packet.

[0127] Unlike the example of FIG. 6B, in the example of FIG. 6C, the first network device 220-1 transmits UL data carrying buffer size information to the second network device 220-2 (662 and 664). More specifically, the first network device 220-1 may transmit the UL data using the GTP-U protocol, and the buffer size information is indicated using the GTP-U extension header "RAN Container." Furthermore, the first network device 220-1 transmits subsequent UL data carrying buffer size information to the second network device 220-2 (666). The buffer size information indicates that the buffer size is zero. The buffer size information included in the subsequent UL data may be considered a fourth indication.

[0128] The second network device 220-2 may then determine that the second condition is met and send an Xn message (carrying the third instruction) to the first network device 220-1 to terminate the connection between the first network device 220-1 and the second network device 220-2 (668). Further in the example of Figure 6C, optionally, the Xn message may carry information for releasing the terminal device's RRC connection. Alternatively, the third instruction is sent via at least one end marker packet.

[0129] The above description fully discusses the process by which the second network device 220-2 initiates the termination of a connection between the first network device 220-1 and the second network device 220-2.

[0130] An exemplary process for a second network device to initiate a content relocation procedure for a terminal device during a UP transmission Reference is now made to Figure 7, which illustrates a signaling flow 700 for UL transmission of a terminal device in an inactive mode, in accordance with some embodiments of the present disclosure. For purposes of discussion, the signaling flow 700 will be described with reference to Figure 2. The signaling flow 700 may involve a first network device 220-1 and a second network device 220-2.

[0131] 7, the first network device 220-1 transmits (710) UL data over the connection established between the first network device 220-1 and the second network device 220-2 for the terminal device 230. Additionally, the first network device 220-2 may transmit (730) additional UL data to the second network device 220-2.

[0132] If the second network device 220-2 determines that the third condition is met, the second network device 220-2 sends a message to initiate a context relocation procedure for the first network device 220-1 (740). The first network device 220-1 may then perform a context relocation procedure for the terminal device. For example, the first network device 220-1 sends a path switch request to a core device (such as an AMF). In this manner, the second network device 220-2 may dynamically and timely determine whether to initiate a context relocation procedure. The third condition is used by the second network device 220-2 to determine whether to initiate content relocation for the terminal device 230.

[0133] In some exemplary embodiments, the message may be sent via signaling sent over the Xn or X2 interface. In some examples, a RETRIEVE UE CONTEXT RESPONSE may be used. In other exemplary embodiments, any suitable message or signaling may be used to send the above message. In this manner, the message to initiate the context relocation procedure may be flexibly sent to the second network device 220-2.

[0134] Also, in some exemplary embodiments, the first network device transmits (720) a fifth instruction to the second network device 220-2, the fifth instruction indicating the amount of data to be transmitted associated with terminal device 230. In this manner, the second network device 220-2 may timely obtain the status of the UL transmission, and if the second network device 220-2 determines that a subsequent UL transmission will burden the second network device 220-2, the second network device 220-2 may timely initiate a context relocation procedure. For example, if the BSR of terminal device 230 increases significantly during a subsequent transmission, the first network device 220-2 may transmit an Xn message to the second network device 220-2 to request the context again, where the Xn message may include updated buffer size information. As a result, the second network device 220-2 may decide to initiate a content relocation procedure.

[0135] In some exemplary embodiments, the fifth indication may be transmitted via signaling transmitted over the Xn or X2 interface. Alternatively, the fifth indication may be transmitted via a header of data transmitted from the first network device to the second network device. For example, the "RAN Container" GTP-U extension header of the GTP-U protocol may be used as the fifth indication to indicate buffer size information (such as BSR).

[0136] It should be understood that the above-described signaling or packets for transmitting the fifth instruction are for illustrative purposes only and do not imply any limitation. In other exemplary embodiments, any suitable message or signaling may be used to transmit the fifth instruction. In this manner, the fifth instruction may be flexibly transmitted to the second network device 220-2.

[0137] Alternatively, or in addition, in some exemplary embodiments, if the second network 220-2 determines that the DL transmissions received from the core device 210 will burden the second network 220-2, the second network 220-2 may determine that the content relocation condition is met and therefore send a message to initiate content relocation.

[0138] Alternatively, or in addition, in some exemplary embodiments, if the second network 220-2 determines that resources (e.g., frequency resources, time resources, code resources, spatial resources, hardware resources, etc.) are insufficient for a subsequent transmission (e.g., subsequent UL data or subsequent DL data), the second network 220-2 may determine that a content relocation condition is met and, accordingly, transmit a message to initiate content relocation.

[0139] It should be understood that the second network device 220-2 may determine whether the content relocation termination condition is met according to any suitable criteria or combination thereof, and in this manner, the second network device 220-2 may more appropriately initiate the content relocation procedure.

[0140] Also, the connection between the first network device 220-1 and the second network device 220-2 should be terminated. The connection termination procedure can then be initiated by either the first network device 220-1 or the second network device 220-2 in any suitable manner, as described above. Furthermore, the connection termination procedure can be performed at any suitable opportunity, such as before or after sending a message to initiate the content relocation procedure, and before or after sending a path switch request.

[0141] In this manner, the second network device 220-2 may dynamically and timely determine whether to initiate a context relocation procedure when subsequent transmissions (including subsequent UL and DL data) will burden the second network device 220-2.

[0142] To better illustrate the above process, some specific examples are provided below, which are for illustrative purposes only and do not imply any limitation.

[0143] 8A and 8B illustrate signaling flows 800 and 850, respectively, for UL transmission in accordance with some embodiments of the present disclosure. For purposes of discussion, the signaling flows 800 and 850 will be described with reference to FIG. 2. The signaling flows 800 and 850 may involve the core device 210 (e.g., the UPF or AMF), the first network device 220-1, the second network device 220-2, and the terminal device 230.

[0144] The signaling flows 800, 850 shown in Figures 8A and 8B are similar to the signaling flow 450 shown in Figure 4B, and the same operations / elements are designated with the same reference numerals. For the sake of brevity, the description of the same operations / elements will be omitted below.

[0145] Referring first to Figure 8A, in the example of Figure 8A, the second network device 220-2 receives (810) a fifth indication, the fifth indication indicating an amount of data associated with the terminal device 230, transmitted from the first network device. In the specific example of Figure 8A, the fifth indication is transmitted via signaling on the Xn interface.

[0146] If the second network device 220-2 determines that the third condition is met, the second network device 220-2 sends a message to the first network device 220-1 to initiate a context relocation procedure (820). In the example of FIG. 8A, the message is sent via signaling on the Xn interface. The first network device 220-1 then sends a path switch request to a core device (e.g., AMF) (830). It should be understood that the second network device 220-2 may alternatively decide not to initiate a context relocation procedure (i.e., the second network device 220-2 may decide to continue subsequent transmissions without UE context relocation). The second network device 220-2 may also send a message to the first network device to maintain the UE context location. In some embodiments, the existing RETRIVE UE CONTEX Failure message can be used. As a result, the first network device still forwards subsequent UP data to the second network device 220-2. In other words, the second device 220-2 may dynamically decide whether to initiate a content relocation procedure, and the related decision result may be transmitted to the first network device 220-1.

[0147] Although not shown in FIG. 8A, it should be understood that the connection between the first network device 220-1 and the second network device 220-2 should be terminated.

[0148] 8A, in the example of FIG. 8B, the first network device 220-1 transmits UL data carrying buffer size information to the second network device 220-2 (852, 854, and 856). More specifically, the first network device 220-1 may transmit the UL data using the GTP-U protocol, and the buffer size information is indicated using the GTP-U extension header "RAN Container." Therefore, the second network device may obtain the status of the UP transmission in a timely manner.

[0149] If the second network device 220-2 determines that the third condition is met, the second network device 220-2 sends a message to the first network device 220-1 to initiate a context relocation procedure (858). In the example of FIG. 8B, the message is sent via signaling on the Xn interface. The first network device 220-1 then sends a path switch request to a core device (e.g., AMF) (860).

[0150] Although not shown in FIG. 8B, it should be understood that the connection between the first network device 220-1 and the second network device 220-2 should be terminated.

[0151] The above description fully discusses the process by which the second network device 220-2 initiates a content relocation procedure during a UP transmission.

[0152] 9 illustrates a flowchart of an example method 900 implemented in the first network device 220-1, according to some example embodiments of the present disclosure. For purposes of discussion, the method 900 will be described from the perspective of the first network device 220-1 with reference to FIG.

[0153] In block 910, the first network device 220-1 transmits the data received from the terminal device 230 in the inactive mode to the second network device 220-2 via the connection established for the terminal device 230 between the first network device 220-1 and the second network device 220-2.

[0154] At block 920, the first network device 220-1 transmits a first indication to the second network device 220-2 indicating termination of data transmission associated with the terminal device 230 in accordance with determining that the first condition is met.

[0155] In some exemplary embodiments, first network device 220-1 receives data from terminal device 230 without information regarding the amount of data being transmitted by terminal device 230 and determines that the first condition is met.

[0156] In some exemplary embodiments, first network device 220-1 receives data including a second indication indicating that there is no more data to be transmitted by terminal device 230 and determines that the first condition is met.

[0157] In some exemplary embodiments, the first network device 220-1 transmits the first indication via one of signaling transmitted over an Xn interface, signaling transmitted over an X2 interface, or at least one end marker packet.

[0158] 10 illustrates a flowchart of an example communication method 1000 implemented in the second network device 220-2, according to some example embodiments of the present disclosure. For purposes of discussion, the method 1000 will be described from the perspective of the second network device 220-2 with respect to FIG. 2.

[0159] In block 1010, the second network device 220-2 receives data from the first network device 220-1 that was received by the first network device 220-1 from the terminal device 230 in the inactive mode via the connection established for the terminal device 230 between the first network device 220-1 and the second network device 220-2.

[0160] At block 1010, the second network device 220-2 receives a first indication from the first network device 220-1 indicating an end of data transmission associated with the terminal device 230. The first indication is sent by the first network device 220-1 according to a first condition.

[0161] In some demonstrative embodiments, the second network device 220-2 receives the first indication via one of signaling transmitted over an Xn interface, signaling transmitted over an X2 interface, or at least one end marker packet.

[0162] 11 illustrates a flowchart of an example method 1100 implemented in the first network device 220-1, according to some example embodiments of the present disclosure. For purposes of discussion, the method 1100 will be described from the perspective of the first network device 220-1 with reference to FIG. 2.

[0163] In block 1110, the first network device 220-1 transmits the data received from the terminal device 230 in the inactive mode to the second network device 220-2 via the connection established for the terminal device 230 between the first network device 220-1 and the second network device 220-2.

[0164] At block 1120, the first network device 220-1 receives a third indication from the second network device 220-2 indicating an end of data transmission associated with the terminal device 230. The third indication is sent by the second network device 220-2 according to a second condition.

[0165] In some exemplary embodiments, the first network device 220-1 receives the third indication via one of signaling transmitted over an Xn interface, signaling transmitted over an X2 interface, or at least one end marker packet.

[0166] In some exemplary embodiments, the first network device 220-1 receives information generated by the second network device 220-2 for releasing a radio resource control (RRC) connection of the terminal device 230, along with a third instruction, from the second network device 220-2, and transmits an RRC release message generated by the first network device 220-1 to the terminal device 230 based on the information.

[0167] In some exemplary embodiments, first network device 220-1 sends a fourth indication to second network device 220-2 indicating that no more data related to terminal device 230 will be transmitted, and receives a third indication from second network device 220-2 indicating the end of data transmission related to terminal device 230.

[0168] In some exemplary embodiments, the first network device 220-1 transmits the fourth instruction via one of signaling transmitted over the Xn interface, signaling transmitted over the X2 interface, at least one end marker packet, or a header of data transmitted from the first network device 220-1 to the second network device 220-2.

[0169] 12 illustrates a flowchart of an example communication method 1200 implemented in the second network device 220-2, according to some example embodiments of the present disclosure. For purposes of discussion, the method 1200 will be described from the perspective of the second network device 220-2 with respect to FIG. 2.

[0170] In block 1210, the second network device 220-2 receives data from the first network device 220-1 that was received by the first network device 220-1 from the terminal device 230 in the inactive mode via the connection established for the terminal device 230 between the first network device 220-1 and the second network device 220-2.

[0171] At block 1220, the second network device 220-2 transmits a third indication to the first network device 220-1 indicating termination of data transmission associated with the terminal device 230 in accordance with determining that the second condition is met.

[0172] In some exemplary embodiments, the second network device 220-2 determines that the second condition is met in response to receiving a fourth indication from the first network device 220-1 indicating that no further data related to the terminal device 230 will be transmitted.

[0173] In some exemplary embodiments, the fourth indication is received via one of signaling transmitted over the Xn interface, signaling transmitted over the X2 interface, at least one end marker packet, or a header of data transmitted from the first network device 220-1 to the second network device 220-2.

[0174] In some exemplary embodiments, the second network device 220-2 transmits the third indication via one of signaling transmitted over an Xn interface, signaling transmitted over an X2 interface, or at least one end marker packet.

[0175] In some exemplary embodiments, second network device 220-2 sends information for releasing a radio resource control (RRC) connection of terminal device 230 along with the third indication.

[0176] 13 illustrates a flowchart of an example method 1300 implemented in the first network device 220-1, according to some example embodiments of the present disclosure. For purposes of discussion, the method 1300 will be described from the perspective of the first network device 220-1 with reference to FIG. 2.

[0177] In block 1310, the first network device 220-1 transmits the data received from the terminal device 230 in the inactive mode to the second network device 220-2 via the connection established for the terminal device 230 between the first network device 220-1 and the second network device 220-2.

[0178] At block 1320, the first network device 220-1 receives a message to initiate a context relocation procedure from the second network device 220-2, the message being sent from the second network device 220-2 according to a third condition.

[0179] In some examples, the first network device 220-1 sends a fifth indication to the second network device 220-2 indicating the amount of data to be transmitted associated with the terminal device 230 and receives a message from the second network device 220-2 to initiate a context relocation procedure.

[0180] In some examples, the first network device 220-1 sends the fifth instruction via one of a header of data sent from the first network device 220-1 to the second network device 220-2, signaling sent over the Xn interface, or signaling sent over the X2 interface.

[0181] 14 illustrates a flowchart of an example communication method 1400 implemented in the second network device 220-2, according to some example embodiments of the present disclosure. For purposes of discussion, the method 1400 will be described from the perspective of the second network device 220-2 with respect to FIG. 2.

[0182] In block 1410, the second network device 220-2 receives data from the first network device 220-1 that was received by the first network device 220-1 from the terminal device 230 in the inactive mode via the connection established for the terminal device 230 between the first network device 220-1 and the second network device 220-2.

[0183] At block 1420, the second network device 220-2, pursuant to determining that the third condition is met, sends a message to the first network device to initiate a context relocation procedure.

[0184] In some examples, the second network device 220-2 receives a fifth indication from the first network device 220-1 indicating the amount of data to be transmitted associated with the terminal device 230 and transmits a message to the first network device 220-1 to initiate a context relocation procedure.

[0185] In some examples, the second network device 220-2 receives the fifth instruction via one of a header of data sent from the first network device 220-1 to the second network device 220-2, signaling sent over the Xn interface, or signaling sent over the X2 interface.

[0186] In some embodiments, the first network device includes circuitry configured to transmit data received from the terminal device in the inactive mode to the second network device at the first network device via a connection established for the terminal device between the first network device and the second network device, and, pursuant to a determination that a first condition is met, transmit a first indication to the second network device indicating termination of data transmission associated with the terminal device 230.

[0187] In some embodiments, the first network device includes circuitry configured to determine that the first condition is met in response to at least one of receiving data from the terminal device that does not include information regarding the amount of data to be transmitted by the terminal device, or receiving data from the terminal device that includes a second indication indicating that there is no more data to be transmitted by the terminal device.

[0188] In some embodiments, the first network device includes circuitry configured to transmit the first indication via one of signaling transmitted over an Xn interface, signaling transmitted over an X2 interface, or at least one end marker packet.

[0189] In some embodiments, the second network device includes circuitry configured to receive from the first network device at the second network device, via a connection established for the terminal device between the first network device and the second network device, data received by the first network device from the terminal device in the inactive mode, and to receive from the first network device a first indication indicating an end of data transmission associated with the terminal device 230. The first indication is transmitted by the first network device in accordance with a first condition.

[0190] In some embodiments, the second network device includes circuitry configured to receive the first indication via one of signaling transmitted over an Xn interface, signaling transmitted over an X2 interface, or at least one end marker packet.

[0191] In some embodiments, the first network device includes circuitry configured to transmit data received from the terminal device in the inactive mode to the second network device at the first network device via a connection established for the terminal device between the first network device and the second network device, and to receive a third indication from the second network device indicating termination of data transmission associated with the terminal device 230. The third indication is transmitted by the second network device in accordance with a second condition.

[0192] In some embodiments, the first network device includes circuitry configured to receive the third indication via one of signaling transmitted over an Xn interface, signaling transmitted over an X2 interface, or at least one end marker packet.

[0193] In some embodiments, the first network device includes circuitry configured to receive information generated by the second network device for releasing a radio resource control (RRC) connection of the terminal device together with a third instruction from the second network device, and to transmit an RRC release message generated by the first network device based on the information to the terminal device.

[0194] In some embodiments, the first network device includes circuitry configured to send a fourth indication to the second network device indicating that no more data associated with the terminal device will be transmitted, and to receive a third indication from the second network device indicating an end of data transmission associated with the terminal device 230.

[0195] In some embodiments, the first network device includes circuitry configured to transmit the fourth instruction via one of signaling transmitted over an Xn interface, signaling transmitted over an X2 interface, at least one end marker packet, or a header of data transmitted from the first network device to the second network device.

[0196] In some embodiments, the second network device includes circuitry configured to receive data received by the first network device from the terminal device in the inactive mode from the first network device at the second network device via a connection established for the terminal device between the first network device and the second network device, and to transmit a third indication to the first network device indicating termination of data transmission associated with the terminal device 230 pursuant to a determination that the second condition is met.

[0197] In some embodiments, the second network device includes circuitry configured to determine that the second condition is satisfied in response to receiving a fourth indication from the first network device indicating that no further data associated with the terminal device will be transmitted.

[0198] In some embodiments, the second network device includes circuitry configured to receive the fourth indication via one of signaling transmitted over an Xn interface, signaling transmitted over an X2 interface, at least one end marker packet, or a header of data transmitted from the first network device to the second network device.

[0199] In some embodiments, the second network device receives signaling transmitted over an Xn interface, signaling transmitted over an X2 interface, or

[0200] and circuitry configured to transmit a third indication via one of the at least one end marker packets.

[0201] In some embodiments, the second network device includes circuitry configured to transmit, along with the third indication, information for releasing a radio resource control (RRC) connection of the terminal device.

[0202] In some embodiments, the first network device includes circuitry configured to transmit data received from the terminal device in the inactive mode to the second network device at the first network device via a connection established for the terminal device between the first network device and the second network device, and to receive a message from the second network device to initiate a context relocation procedure, the message being transmitted by the second network device according to a third condition.

[0203] In some embodiments, the first network device includes circuitry configured to send a fifth indication to the second network device indicating an amount of data to be transmitted associated with the terminal device and to receive a message from the second network device to initiate a context relocation procedure.

[0204] In some embodiments, the first network device includes circuitry configured to transmit the fifth instruction via one of a header of data transmitted from the first network device to the second network device, signaling transmitted over an Xn interface, or signaling transmitted over an X2 interface.

[0205] In some embodiments, the second network device includes circuitry configured to receive data received by the first network device from the terminal device in an inactive mode from the first network device at the second network device via a connection established for the terminal device between the first network device and the second network device, and to send a message to the first network device to initiate a context relocation procedure in accordance with a determination that a third condition is met.

[0206] In some embodiments, the second network device includes circuitry configured to receive from the first network device a fifth indication indicating an amount of data to be transmitted associated with the terminal device and to transmit a message to the first network device to initiate a context relocation procedure.

[0207] In some embodiments, the second network device includes circuitry configured to receive the fifth indication via one of a header of data transmitted from the first network device to the second network device, signaling transmitted over an Xn interface, or signaling transmitted over an X2 interface.

[0208] 15 is a schematic block diagram of an apparatus 1500 suitable for implementing exemplary embodiments of the present disclosure. The apparatus 1500 may be provided to implement communications devices such as the first network device 220-1 and the second network device 220-2 shown in FIG. 2. As shown, the apparatus 1500 includes one or more processors 1510, one or more memories 1520 coupled to the processors 1510, and one or more communications modules 1540 coupled to the processors 1510.

[0209] The communications module 1540 is for two-way communication. The communications module 1540 has one or more communications interfaces to facilitate communication with one or more other modules or devices. The communications interfaces may represent any interface necessary for communication with other network elements. In some exemplary embodiments, the communications module 1540 may include at least one antenna.

[0210] The processor 1510 may be of any type suitable for a local technology network, including, by way of example and not limitation, one or more of a general purpose computer, a special purpose computer, a microprocessor, a digital signal processor (DSP), and a processor based on a multi-core processor configuration. The device 1500 may have multiple processors, for example, application specific integrated circuit chips time-slaved to a clock synchronized with a master processor.

[0211] Memory 1520 may include one or more non-volatile memories and one or more volatile memories. Examples of non-volatile memory include, but are not limited to, read-only memory (ROM) 1524, electrically programmable read-only memory (EPROM), flash memory, hard disks, compact discs (CDs), digital video disks (DVDs), optical disks, laser disks, and other magnetic and / or optical storage devices. Examples of volatile memory include, but are not limited to, random access memory (RAM) 1522 and other volatile memories that do not retain information when powered off.

[0212] The computer program 1530 includes computer-executable instructions that are executed by the associated processor 1510. The program 1530 may be stored in a memory, such as the ROM 1524. The processor 1510 may load the program 1530 into the RAM 1522 to perform any suitable operations and processes.

[0213] An exemplary embodiment of the present disclosure may be implemented by a program 1530 such that the device 1500 can perform any of the processes of the present disclosure discussed with reference to Figures 1 to 14. An exemplary embodiment of the present disclosure may be implemented by hardware or a combination of software and hardware.

[0214] In some exemplary embodiments, the program 1530 may be tangibly embodied in a computer-readable medium, which may be included in the device 1500 (such as in memory 1520) or in other storage accessible by the device 1500. The device 1500 may load the program 1530 from the computer-readable medium into RAM 1522 for execution. The computer-readable medium may include any type of non-volatile tangible storage device, such as ROM, EPROM, flash memory, hard disk, CD, DVD, etc.

[0215] Generally, various embodiments of the present disclosure may be implemented by hardware or special purpose circuits, software, logic, or any combination thereof. Some aspects may be implemented by hardware, while other aspects may be implemented by firmware or software that may be executed by a controller, microprocessor, or other computing device. While various aspects of the embodiments of the present disclosure are shown and described as block diagrams, flowcharts, or illustrated by some other pictorial representation, it should be understood that the blocks, apparatus, systems, techniques, or methods described herein may be implemented by, for example, but not limited to, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing device, or combinations thereof.

[0216] The present disclosure further provides at least one computer program product tangibly stored on a computer-readable, non-transitory storage medium. The computer program product includes computer-executable instructions, such as instructions included in program modules. The instructions execute on a target real or virtual processor device to perform any of the methods described above with reference to FIGS. 3-7. Typically, program modules include routines, programs, libraries, objects, classes, components, data structures, etc. that perform particular tasks or implement particular abstract data types. In various embodiments, the functionality of the program modules may be combined or split among program modules as desired. The machine-readable instructions of the program modules may be executed in local or distributed devices. In distributed devices, the program modules may be located in both local and remote storage media.

[0217] Program code for carrying out the methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus, and when executed by the processor or controller, the functions / operations specified in the flowcharts and / or block diagrams are performed. The program code may run entirely on the machine, partially on the machine, as a separate software package, partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0218] In the context of the present disclosure, computer program code or associated data may be carried by any suitable carrier to enable a device, apparatus, or processor to perform the various processes and operations described above. Examples of carriers include signals, computer-readable media, etc.

[0219] The computer-readable medium may be a computer-readable signal medium or a computer-readable storage medium. The computer-readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. Even more specific examples of computer-readable storage media include 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.

[0220] Although operations have been described in a particular order, it should not be understood that performing these operations in the particular order or sequence shown, or performing all of the operations shown, is required to achieve desired results. In some situations, multitasking and parallel processing may be advantageous. Similarly, while the above discussion includes several specific implementation details, these should not be construed as limitations on the scope of the disclosure, but rather as descriptions of features that may be specific to particular embodiments. Some features that are described in the context of individual embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable subcombination.

[0221] Although the present disclosure has been described in language specific to structural features and / or methodological acts, it is to be understood that the present disclosure, as defined by the appended claims, is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. means for sending a Retrieve USER EQUIPMENT (UE) Context Request message to a second network device; means for receiving a portion of a context for the terminal device from the second network device; means for transmitting a first message to the second network device, the first message including a reason for terminating a small data transmission (SDT) procedure; means for receiving a second message from the second network device, the second message comprising a Radio Resource Control (RRC) release message; means for transmitting the RRC release message to the terminal device; Including, The second message is a RETRIEVE UE CONTEXT FAILURE message. A first network device.

2. The reason for terminating the SDT procedure includes: there are no more packets to be sent; or the uplink SDT data in the Buffer Status Report (BSR) is large. The first network device of claim 1 .

3. After the SDT procedure is completed by the second network device, downlink data transmission between the first network device and the second network device is stopped. The first network device of claim 1 .

4. The transmission of the first message and the reception of the second message are performed via an Xn interface. The first network device of claim 1 .

5. sending a Retrieve USER EQUIPMENT (UE) Context Request message to a second network device; receiving a portion of a context for the terminal device from the second network device; sending a first message to the second network device, the first message including a reason for terminating a small data transmission (SDT) procedure; receiving a second message from the second network device, the second message comprising a radio resource control (RRC) release message; sending the RRC release message to the terminal device; Including, The second message is a RETRIEVE UE CONTEXT FAILURE message. A method performed by a first network device.

6. The reason for terminating the SDT procedure includes: there are no more packets to be sent; or the uplink SDT data in the Buffer Status Report (BSR) is large. The method of claim 5.

7. After the SDT procedure is completed by the second network device, downlink data transmission between the first network device and the second network device is stopped. The method of claim 5.

8. The transmission of the first message and the reception of the second message are performed via an Xn interface. The method of claim 5.

9. means for receiving a Retrieve User Equipment (UE) Context Request message from a first network device; means for transmitting a portion of a context for the terminal device to the first network device; means for receiving a first message from the first network device, the first message including a reason for terminating a small data transmission (SDT) procedure; means for sending a second message to the first network device, the second message including a Radio Resource Control (RRC) release message, if the first network device receives the first message and decides to terminate the SDT procedure; Including, The second message is a RETRIEVE UE CONTEXT FAILURE message. A second network device.

10. The reason for terminating the SDT procedure includes: there are no more packets to be sent; or the uplink SDT data in the Buffer Status Report (BSR) is large. The second network device of claim 9.

11. After completing the SDT procedure, downlink data transmission between the first network device and the second network device is stopped. The second network device of claim 9.

12. The reception of the first message and the transmission of the second message are performed via an Xn interface. The second network device of claim 9.

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