drop notification

Abstract

Example embodiments of the present disclosure relate to devices, methods, apparatuses, and computer-readable storage media for discard notification. In one method, an access node (AN) receives, from a user plane function, at least one protocol data unit (PDU) belonging to a set of PDUs. Based on detecting that one or more PDUs belonging to the set of PDUs have been lost or discarded, the AN transmits, to the UPF, a discard notification when at least one condition has been met. The discard notification indicates that the UPF is to discard, at the UPF, the one or more PDUs belonging to the set of PDUs.

Description

Technical Field

[0001] Various exemplary embodiments of this disclosure generally relate to the telecommunications field, and more specifically to devices, methods, apparatuses, and computer-readable storage media for notifying user plane functions of a telecommunications network to discard PDUs belonging to a set of Protocol Data Units (PDUs). Background Technology

[0002] Extended Reality (XR) services include services based on various types of reality, such as Virtual Reality (VR), Augmented Reality (AR), and Mixed Reality (MR). XR services are provided to communication devices (e.g., user equipment) by XR application servers (e.g., servers hosting XR applications). The XR application server can send downlink (DL) PDUs (e.g., one or more Protocol Data Units (PDUs) carrying an information element generated by an XR application, such as a frame or video slice used for extended reality (XR) services) to the communication device via a telecommunications network including the User Plane Function (UPF) of the core network and access nodes of the access network. All PDUs belonging to a PDU set can be transmitted within a Quality of Service (QoS) stream. When Integrated Processing Information (PSIHI) is set for a QoS stream in the access node, if it is known that a PDU belonging to the PDU set is lost or discarded, the remaining PDUs in that PDU set can be considered no longer needed by the application layer and can be discarded. Summary of the Invention

[0003] In a first aspect of this disclosure, an access node is provided. The access node includes: at least one processor; and at least one memory storing instructions, which, when executed by the at least one processor, cause the access node to at least: receive at least one PDU belonging to a set of Protocol Data Units (PDUs) from a user plane function; and determine to transmit a discard notification to the user plane function based on the detection that one or more PDUs belonging to the PDU set have been lost or discarded, wherein the discard notification indicates that the user plane function will discard one or more PDUs belonging to the PDU set at the user plane function.

[0004] In a second aspect of this disclosure, an apparatus is provided. The apparatus includes: at least one processor; and at least one memory storing instructions for network functions, the instructions, when executed by the at least one processor, causing the apparatus to at least: transmit an activation request to an access node based on determining that at least one condition is met, wherein the activation request instructs the access node to determine whether to transmit a drop notification to a user plane function in response to detecting that one or more PDUs belonging to a set of Protocol Data Units (PDUs) have been lost or dropped.

[0005] In a third aspect of this disclosure, an apparatus is provided. The apparatus includes: at least one processor; and at least one memory storing instructions for a user plane function, the instructions, when executed by the at least one processor, causing the apparatus to at least: receive a discard notification for a set of PDUs, wherein the discard notification indicates that the user plane function will discard one or more PDUs belonging to the set of PDUs at the user plane function, and discard one or more PDUs belonging to the set of PDUs at the user plane function.

[0006] In a fourth aspect of this disclosure, a method is provided. The method includes: receiving from a user plane function at least one PDU belonging to a set of Protocol Data Units (PDUs); and determining to transmit a discard notification to the user plane function based on the detection that one or more PDUs belonging to the PDU set have been lost or discarded, and upon at least one condition being met, wherein the discard notification indicates that the user plane function will discard one or more PDUs belonging to the PDU set at the user plane function.

[0007] In a fifth aspect of this disclosure, a method is provided. The method includes: transmitting an activation request to an access node based on determining that at least one condition is met, wherein the activation request instructs the access node to determine whether to transmit a drop notification to a user plane function in response to detecting that one or more PDUs belonging to a set of Protocol Data Units (PDUs) have been lost or discarded.

[0008] In a sixth aspect of this disclosure, a method is provided. The method includes: receiving a discard notification for a set of PDUs, wherein the discard notification instructs a user plane function to discard one or more PDUs belonging to the set of PDUs at the user plane function; and discarding one or more PDUs belonging to the set of PDUs at the user plane function.

[0009] In a seventh aspect of this disclosure, a first apparatus is provided. The first apparatus includes: means for receiving from a user plane function at least one PDU belonging to a set of Protocol Data Units (PDUs); and means for determining to transmit a discard notification to the user plane function based on the detection that one or more PDUs belonging to the PDU set have been lost or discarded, wherein the discard notification indicates that the user plane function will discard one or more PDUs belonging to the PDU set at the user plane function.

[0010] In an eighth aspect of this disclosure, a second apparatus is provided. The second apparatus includes components for transmitting an activation request to an access node based on determining that at least one condition is met, wherein the activation request instructs the access node to determine whether to transmit a drop notification to a user plane function in response to detecting that one or more PDUs belonging to a protocol data unit (PDU) set have been lost or discarded.

[0011] In a ninth aspect of this disclosure, a third apparatus is provided. The third apparatus includes: components for receiving a discard notification for a PDU set, wherein the discard notification instructs a user plane function to discard one or more PDUs belonging to the PDU set at the user plane function; and components for discarding one or more PDUs belonging to the PDU set at the user plane function.

[0012] In a tenth aspect of this disclosure, a computer-readable medium is provided. The computer-readable medium includes instructions stored thereon for causing a device to execute at least the method according to the fourth, fifth, or sixth aspect.

[0013] It should be understood that the summary portion is not intended to identify key or essential features of the embodiments of this disclosure, nor is it intended to limit the scope of this disclosure. Other features of this disclosure will become readily apparent from the following description. Attached Figure Description

[0014] Some exemplary embodiments will now be described with reference to the accompanying drawings, in which: Figure 1 An example communication network for connecting a user device to an extended reality application server in which example embodiments of the present disclosure may be implemented is shown; Figure 2 Signaling diagrams of example processes according to some example embodiments of this disclosure are shown; Figure 3 A flowchart is shown illustrating an example method for an access node according to some example embodiments of this disclosure; Figure 4 Some other example embodiments of the present disclosure are shown for use with Figure 1 A flowchart illustrating an example method for the network functions of the core network of the communication network shown. Figure 5 A flowchart is shown for another example method for user plane functionality according to some other example embodiments of this disclosure; Figure 6 It shows what is suitable for implementation Figure 1 A simplified block diagram of a computing system for one or more core network functions of the communication network shown; and Figure 7 A block diagram of an example computer-readable medium according to some example embodiments of the present disclosure is shown.

[0015] In all the accompanying drawings, the same or similar reference numerals denote the same or similar elements. Detailed Implementation

[0016] The principles of this disclosure will now be described with reference to some exemplary embodiments. It should be understood that these embodiments are described for illustrative purposes only and to assist those skilled in the art in understanding and implementing this disclosure, and do not imply any limitation on the scope of this disclosure. The embodiments described herein can be implemented in various ways other than those described below.

[0017] In the following description and claims, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains.

[0018] References to "an embodiment," "embodiment," "example embodiment," etc., in this disclosure indicate that the described embodiment may include a particular feature, structure, or characteristic, but not every embodiment must include that particular feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Additionally, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is believed that incorporating other embodiments, whether explicitly described or not, to affect such a feature, structure, or characteristic is within the knowledge of those skilled in the art.

[0019] It should be understood that although terms such as "first," "second," etc., preceding nouns may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another, and they do not restrict the order of the nouns. For example, without departing from the scope of the exemplary embodiments, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element. As used herein, the term "and / or" includes any and all combinations of one or more of the listed terms.

[0020] As used herein, “at least one of the following: ” and “at least one of ” and similar wording (where the list of two or more elements is connected by “and” or “or”) means at least any one of the elements, or at least any two or more of the elements, or at least all of the elements.

[0021] As used herein, unless explicitly stated otherwise, the execution step “in response to A” does not indicate that the step is performed immediately after “A” occurs, and may include one or more intermediate steps.

[0022] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that, when used herein, the terms “comprising,” “including,” “having,” “having,” “including,” and / or “containing” specify the presence of a feature, element, and / or component, etc., but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof.

[0023] As used in this application, the term "circuit system" may refer to one or more of the following: (a) Hardware circuit implementation only (such as implementation in analog and / or digital circuit systems only) and (b) A combination of hardware circuitry and software, such as (if applicable): (i) A combination of (multiple) analog and / or digital hardware circuits with software / firmware, and (ii) Any part of a hardware processor(s) having software (including (multiple) digital signal processors), software, and (multiple) memories, which work together to enable a device such as a mobile phone or server to perform various functions, and (c) (Multiple) hardware circuits and / or (multiple) processors (such as (multiple) microprocessors or a portion of (multiple) microprocessors) that require software (e.g., firmware) to operate, but which may be absent when no software is required to operate.

[0024] This definition of "circuit system" applies to all uses of the term "circuit system" in this application (including in any claim). As another example, as used in this application, the term "circuit system" also covers implementations of hardware circuitry or processors (or processors in general) and their accompanying software and / or firmware. For instance, where applicable to a particular claim element, the term "circuit system" also covers baseband integrated circuits or processor integrated circuits for mobile devices or similar integrated circuits in servers, cellular network devices, or other computing or network devices.

[0025] As used herein, the term "communication network" refers to a network that follows any suitable communication protocol, 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), sixth-generation (6G) communication protocols and / or any other protocols currently known or to be developed in the future. Embodiments of this disclosure can be applied to a variety of communication systems. Given the rapid development of communications, there will certainly be future types of communication technologies and systems that embody the nature of this disclosure. The scope of this disclosure should not be construed as limited to the aforementioned systems.

[0026] As used herein, the term "access node" or "access network node" refers to a device in a communications network through which user equipment accesses and receives services from the core network. An access network node can be a radio access network node or a wired access network node. Examples of radio access network nodes may include, but are not limited to, base stations (BS) or access points (APs), such as Node B (NodeB or NB), evolved Node B (eNodeB or eNB), NR NB (also known as gNB), next-generation radio access network node (also known as NG-RAN node), remote radio unit (RRU), radio head (RH), remote radio head (RRH), relay, integrated access and backhaul (IAB) node, low-power node (such as femtosecond, picosecond, non-terrestrial network (NTN)) or non-terrestrial network equipment (such as satellite network equipment, low Earth orbit (LEO) satellites and geostationary Earth orbit (GEO) satellites), spacecraft network equipment, etc., depending on the terminology and technology applied. In some example embodiments, a RAN node (e.g., a gNB) may include a centralized unit (CU) and one or more distributed units (DUs) connected to the CU. Examples of wireless access network nodes may include, but are not limited to, wired 5G access network (W-5GAN) nodes, such as wired 5G BBF access network (W-5GBAN) nodes or wired 5G cable access network (W-5GCAN) nodes.

[0027] As used herein, a core network device or core network function can be any computing device or computing system that includes hardware (e.g., at least one processor and at least one memory) and software comprising one or more core network functions. Examples of core network devices may include, but are not limited to, evolved packet data gateways (ePGWs), trusted wireless LAN access network (TWAN) nodes, home subscriber servers (HSSs), access and mobility management functions (AMFs), session management functions (SMFs), network slice selection functions (NSSFs), serving gateways (SGWs), packet data network (PDN) gateways (PGWs), authentication server functions (AUSFs), subscription identifier de-hiding functions (SIDFs), unified data management (UDMs), secure edge protection brokers (SEPPs), network open functions (NEFs), user plane functions (UPFs), and / or policy control functions (PCFs).

[0028] The term "user equipment" refers to any device capable of wireless communication with a communication network. By way of example and not limitation, user equipment may also be referred to as communication equipment, terminal equipment, subscriber station (SS), portable subscriber station, mobile station (MS), or access terminal (AT). User equipment can be mobile phones, cellular phones, smartphones, Voice over IP (VoIP) phones, wireless local loop phones, tablets, wearable terminal devices, personal digital assistants (PDAs), portable computers, desktop computers, image capture 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 devices (LEEs), laptop-mounted devices (LMEs), USB dongles, smart devices, wireless customer premises equipment (CPEs), Internet of Things (IoT) devices, watches or other wearable devices, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in the context of industrial and / or automated processing chains), consumer electronics devices, devices operating on commercial and / or industrial wireless networks, etc. The terminal equipment may also correspond to the mobile termination (MT) portion of an IAB node (e.g., a relay node). In the following description, the terms "terminal equipment," "communication equipment," "terminal," "user equipment," and "UE" are used interchangeably.

[0029] As used herein, the terms “resource,” “transmission resource,” “resource block,” “physical resource block” (PRB), “uplink resource,” or “downlink resource” can refer to any resource used to perform communication, such as communication between a user equipment and an access node, including resources in the time domain, frequency domain, spatial domain, code domain, or any other combination of time, frequency, spatial, and / or code domain resources used to implement communication. In the following, unless explicitly stated otherwise, resources in the frequency and time domains will be used as examples of transmission resources used to describe some exemplary embodiments of this disclosure. Note that the exemplary embodiments of this disclosure are equally applicable to other resources in other domains.

[0030] As used herein, the term “extended reality” or “XR” refers to a combination of real and virtual environments in which human-computer interaction is generated by computers and wearable devices (e.g., user devices). XR is an overarching term for different types of reality, such as virtual reality (VR), augmented reality (AR), mixed reality (MR), etc.

[0031] As used herein, the term "protocol data unit set" or "PDU set" includes one or more protocol data units (PDUs) that carry the payload of a single unit of information generated at the application level (e.g., multiple video frames, multiple video slices, etc., for XR services). All PDUs belonging to a PDU set are transmitted within a single Quality of Service (QoS) stream.

[0032] PDU-based QoS processing performed by access nodes (e.g., Next-Generation Radio Access Network (NG-RAN)) is based on PDU-based QoS parameters such as PDU-based Delay Budget (PSDB), PDU-based Error Rate (PSER), and PDU-based Integrated Processing Information (often referred to as PDU-based Integrated Processing Information (PSIHI)). PSIHI indicates whether the application layer in the receiver (e.g., user equipment) requires all PDUs belonging to the PDU-based set. When PSIHI is set for a QoS flow, if it is known that one PDU belonging to the PDU-based set is lost, the remaining PDUs belonging to that set can be considered no longer needed by the application layer and can be discarded by the transmitter (e.g., UPF in a 5G core network).

[0033] To support QoS processing based on PDU sets, the PDU Session Anchor (PSA) User Plane Function (UPF) identifies PDUs belonging to a PDU set and determines the following information about the PDU set (commonly referred to as PDU set information). The PSA-UPF sends this information to the NG-RAN node in the General Packet Radio Service (GPRS) Tunnel Transport Protocol User Plane (GTP-U) header. The PDU set information is used by the NG-RAN node for QoS processing based on PDU sets. The PDU set information may include the sequence number of the PDU set (also known as the PDU set sequence number), an indication of the last PDU belonging to the PDU set, the sequence numbers of the PDUs within the PDU set (also known as the PDU sequence numbers), and / or the size of the PDU set in bytes (also known as the PDU set size).

[0034] PDU set information can also include PDU set importance (PSI), which identifies the relative importance of a PDU set compared to other PDU sets within a QoS flow. In the event of congestion, NG-RAN nodes can use cross-QoS flow priority and PSI within a QoS flow to drop packets at the PDU set level.

[0035] The PDU set may include PDUs for video frames. These PDUs may be quite large (e.g., 1500 bytes). Many of these PDUs are needed to transmit video frames. The downlink (DL) PDU set may include one or more of the following DL PDUs: multiple DL PDUs already transmitted to the User Equipment (UE); multiple DL PDUs buffered in an NG-RAN node (e.g., gNB) awaiting transmission to the UE; multiple DL PDUs buffered in a UPF awaiting transmission to an NG-RAN node (e.g., gNB); multiple DL PDUs buffered in an application server (AS) hosting the XR application awaiting transmission to the PSA-UPF; and potential DL PDUs buffered in intermediate transport network nodes (e.g., routers) between the PSA-UPF and the AS.

[0036] If PSIHI is set for QoS flows and PDUs belonging to a PDU set are dropped in the NG-RAN node (e.g., gNB), for example, if a DL PDU is dropped when the PDCP drop timer expires, then there is no need to continue buffering and transmitting the remaining PDUs belonging to the PDU set. The NG-RAN node (e.g., gNB) can drop buffered DL PDUs belonging to the same PDU set. However, there may be some PDUs belonging to a PDU set that have already been buffered and have not yet been transmitted to the NG-RAN node (e.g., gNB). For example, such PDUs may include PDUs buffered in the PSA-UPF and AS. If these PDUs continue to be transmitted to the NG-RAN node (e.g., gNB), it may waste resources of the transport network between the PSA-UPF and AS, as well as resources of the access network between the NG-RAN node and the UE.

[0037] Furthermore, when the UE is in a handover (HO) to a target NG-RAN node (e.g., gNB), the source NG-RAN node may have already discarded one or more PDUs belonging to the PDU set. After the UE connects to the target NG-RAN node, the UPF sends the remaining PDUs belonging to the PDU set to the target NG-RAN node. However, the target NG-RAN node (e.g., gNB) cannot know that (multiple) PDUs belonging to the PDU set may have been discarded and can continue to transmit these PDUs to the UE. Due to the lack of all PDUs belonging to the PDU set, these PDUs will eventually be discarded by the UE. This is wasteful for the UPF to forward the remaining PDUs of the affected PDU set to the target NG-RAN node, and for the NG-RAN node to transmit the remaining PDUs of the affected PDU set to the UE.

[0038] Therefore, when an NG-RAN node (e.g., gNB) has determined that a PDU belonging to the PDU set can be discarded, it is necessary to avoid buffering and / or transmitting the remaining DL PDUs belonging to the PDU set.

[0039] An example embodiment of this disclosure proposes a drop notification solution. In this solution, an access node receives at least one PDU belonging to a set of Protocol Data Units (PDUs) from a user plane function. Based on the detection that one or more PDUs belonging to the PDU set have been lost or dropped, and when at least one condition has been met, the access node transmits a drop notification to the user plane function. The drop notification indicates that the user plane function will drop one or more PDUs belonging to the PDU set at the user plane function.

[0040] As an example, if the gNB has determined that a PDU set cannot be successfully transmitted because some PDUs belonging to the set have been lost, the gNB can determine to transmit a drop notification to the UPF, instructing the UPF to discard buffered or received PDUs belonging to the affected PDU set. Therefore, storage and processing resources of core network equipment, including or implementing the UPF, can be saved. Furthermore, resources of the communication network can be saved, and the capacity of the communication network can be increased.

[0041] Figure 1 An example communication network 100 for connecting a user device to an extended reality application server is shown, in which example embodiments of the present disclosure can be implemented.

[0042] Communication network 100 includes UE 110 and access node (AN) 120 (such as gNB) that can communicate with each other. The communication link or link from AN 120 to UE 110 is referred to as DL, while the communication link or link from UE 110 to AN 120 is referred to as UL. In the DL, AN 120 is a transmission (TX) device (or transmitter), and UE 110 is a reception (RX) device (or receiver). In the UL, UE 110 is a TX device (or transmitter), and AN 120 is an RX device (or receiver).

[0043] The communication network 100 also includes one or more network functions of the core network (generally referred to as core network functions), which may include a UPF 130, an Access and Mobility Management Function (AMF) 140, a Session Management Function (SMF) 150, and a Policy Control Function (PCF) 160. The UPF 130 may be capable of data buffering, routing, and transmission. PDU and PDU sets may be transmitted between the AN 120 and the UPF 130 via a user plane protocol (e.g., General Packet Radio System (GPRS) Tunnel Transport Protocol User Plane (GTP-U)). In some example embodiments, the UPF 130 may transmit DL PDUs configured by the XR application server 165 to the AN 120 and further to the UE 110.

[0044] SMF 150 is a network function in the control plane that interacts with network elements in the user plane and provides PDU session management. AMF 140 can transmit session management messages between AN 120 and SMF 150. PCF 160 can provide Policy Charging and Control (PCC) rules for policy control to SMF 150. Control signaling can be transmitted between AN 120 and control plane functions such as AMF 140, SMF 150, and PCF 160.

[0045] Communication in communication network 100 can be implemented according to any suitable communication protocol, including but not limited to cellular communication protocols such as first-generation (1G), second-generation (2G), third-generation (3G), fourth-generation (4G), fifth-generation (5G), and sixth-generation (6G), wireless local network communication protocols such as IEEE 802.11, and / or any other currently known or future-developed protocols. Furthermore, communication can utilize any suitable wireless communication technology, including but not limited to: Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Frequency Division Duplex (FDD), Time Division Duplex (TDD), Multiple-Input Multiple-Output (MIMO), Orthogonal Frequency Division Multiple Access (OFDM), Discrete Fourier Transform Extended OFDM (DFT-s-OFDM), and / or any other currently known or future-developed technologies.

[0046] It should be understood that Figure 1 The types and numbers of devices shown are for illustrative purposes only and do not imply any limitation. Communication network 100 may include any number of access network devices and core network devices configured to implement exemplary embodiments of this disclosure. Furthermore, communication network 100 may include other devices. For example, communication network 100 may include one or more application functions or servers capable of transmitting data with UPF 130.

[0047] In communication network 100, within the DL, PDUs of a PDU set can be transmitted from an application server (not shown) to UPF 130, further to AN 120, and then to UE 110. After UPF 130 receives PDUs belonging to the PDU set from the application server, UPF 130 can buffer these PDUs and then transmit them to AN 120 in batches. During the transmission of PDUs from UPF 130 to AN 120, some PDUs belonging to the PDU set can be buffered in UPF 130 and await transmission to AN 120.

[0048] According to some example embodiments of this disclosure, if AN 120 detects that one or more PDUs belonging to a PDU set have been lost or discarded, AN 120 transmits a discard notification to UPF 130, enabling UPF 130 to discard buffered PDU(s) awaiting transmission to AN 120, as well as other PDUs from the same PDU set that will be received, for example, from an application server. Reference will be made below. Figure 2 This section discusses some example implementations of this discard notification.

[0049] Figure 2 A signaling diagram of an example process 200 according to some example embodiments of the present disclosure is shown.

[0050] like Figure 2 As shown, AN 120 receives (202) at least one PDU belonging to the PDU set from UPF 130. In some example embodiments, AN 120 may receive (205) an activation request for a drop notification. The activation request instructs AN 120 to determine whether to transmit a drop notification to the User Plane Function UPF 130 in response to detecting that one or more PDUs belonging to the Protocol Data Unit (PDU) set have been detected as lost or dropped by the access node. In some example embodiments, the activation request may be transmitted from UPF 130 to AN 120 (210). For example, the activation request (210) may be transmitted from UPF 130 to AN 120 in the User Plane Protocol, such as via the General Packet Radio Service (GPRS) Tunnel Transport Protocol (GTP) User Plane (GTP-U).

[0051] In some other example embodiments, the activation request may be transmitted from SMF 150 to AN 120 via AMF 140 (215). For example, the activation request may be transmitted from SMF 150 to AMF 140 (215). AMF 140 may then transmit it to AN 120, for example, via N2 in control plane signaling (216). In some example embodiments, AN 120 may receive the activation request from SMF 150 via AMF 140 (205).

[0052] In some example embodiments, the activation request may be based on a decision made by PCF 160 regarding an activation drop notification. In some example embodiments, this decision by PCF 160 may include an activation request, which is transmitted from PCF 160 to SMF 150 and further via AMF 140 to AN 120 (217). For example, the decision may be published in a PCC rule sent to SMF 150 and further to AN 120. In some example embodiments, the decision by PCF 160 may include an instruction instructing SMF 150 to transmit the activation request to AN 120.

[0053] In some example embodiments, UPF 130, SMF 150, or PCF 160 may determine whether an activation request should be transmitted based on at least one condition. In an example, UPF 130, SMF 150, or PCF 160 may determine whether at least one condition is met. If it is determined that an activation request should be transmitted based on at least one condition, UPF 130, SMF 150, or PCF 160 may transmit the activation request to AN 120. In this way, UPF 130, SMF 150, or PCF 160 may dynamically request activation or deactivation of a discard notification from AN 120.

[0054] (Multiple) conditions may relate to the number of PDUs belonging to the PDU set. For example, if the number of PDUs belonging to the PDU set or typical PDU set exceeds a threshold, UPF 130, SMF 150, or PCF 160 may activate a drop notification from AN 120. If the PDU set or typical PDU set contains only a few PDUs, it may not be worthwhile to activate a drop notification from AN 120. In this case, UPF 130, SMF 150, or PCF 160 may decide not to activate a drop notification from AN 120.

[0055] Alternatively or additionally, other criteria may be considered for UPF 130, SMF 150, or PCF 160. For example, the conditions(s) used to make the decision may be related to the memory usage, load status (or conditions) of UPF 130. For example, a high-load UPF may wish to reduce the number of DL PDUs in its buffer. Therefore, for such a UPF, a discard notification from AN 120 may be activated.

[0056] Alternatively or additionally, conditions (multiple) can be related to PSIHI. For example, activation can be requested only when PSIHI is set for a QoS flow. Alternatively or additionally, conditions (multiple) can be related to the requirement for successful transmission of all PDUs belonging to the PDU set. This requirement can be indicated by a new parameter that indicates the proportion of PDUs belonging to the PDU set that must be successfully received by the application so that the PDU set can be successfully decoded.

[0057] Alternatively or additionally, conditions may relate to media stream characteristics associated with a PDU set. A PDU belonging to a PDU set is a PDU of a media stream provided by an Application Function (AF). Media stream characteristics associated with a PDU set (e.g., PDU set information) can be determined at UPF 130 based on a "protocol description" sent from AF to PCF 160, then to SMF 150, and further to UPF 130, as well as information in the transport protocol header provided by AF (such as the new Real-Time Transport Protocol (RTP) header extension defined by SA4). Alternatively, the determination of media stream characteristics is left to be implemented on UPF 130. In the example, UPF 130, SMF 150, or PCF 160 may decide not to activate a drop notification from AN 120 based on media stream characteristics that are not worth sending a drop notification for any PDU set. For example, if the typical PDU set of a media stream is only a pair of PDUs, a drop notification may not be activated for the PDU set of the media stream.

[0058] It should be understood that the decisions made by UPF 130, SMF 150, or PCF 160, and the discard notifications transmitted by UPF 130, SMF 150, or PCF 160, are illustrative only and are not limited thereto. In some example embodiments, the activation request for AN 120 may be provided by the Operations Management and Maintenance (OAM) server. In some other example embodiments, the decision may be made, and therefore the activation request may be transmitted by other application functions of the core network.

[0059] After AN 120 receives (205) at least one PDU belonging to the PDU set from UPF 130, AN 120 detects (220) whether one or more PDUs belonging to the PDU set have been lost or discarded. For example, AN 120 may detect that a PDU has been lost or discarded based on a discard timer. For example, when AN 120 sends a DL PDU to UE 110, AN 120 may start a discard timer, such as a discardTimer in the Packet Data Convergence Protocol (PDCP) layer. When AN 120 receives an acknowledgment from UE 110, AN 120 stops the discardTimer. For example, if AN 120 receives a Packet Data Convergence Protocol (PDCP) status report indicating that the DL PDU has been successfully received by UE 110, AN 120 may determine that an acknowledgment has been received from UE 110. If AN 120 fails to receive an acknowledgment when the discardTimer expires, AN 120 may consider the DL PDU to be lost.

[0060] If AN 120 detects (220) that one or more PDUs belonging to the PDU set have been lost or discarded, then AN 120 transmits (225) a discard notification to UPF 130 when at least one condition has been met. The discard notification instructs UPF 130 to discard (235) one or more PDUs belonging to the PDU set at UPF 130.

[0061] In some example embodiments, if one or more PDUs belonging to the PDU set are discarded or lost, AN 120 may determine that a discard notification needs to be provided to UPF 130 based on at least one condition. In some example embodiments, an activation request received by AN 120 (205) may trigger AN 120 to make such a determination. In the example, if an activation request is received (205), AN 120 may determine whether to transmit a discard notification to UPF 130 based on (multiple) conditions.

[0062] In some example embodiments, at least one condition may include the condition that the last PDU in the PDU set has not yet been received at AN 120. If AN 120 detects that a PDU belonging to the PDU set has been lost or discarded, and the last PDU belonging to the PDU set has not yet been received from UPF 130, then AN 120 may send a discard notification to UPF 130.

[0063] Alternatively or additionally, the at least one condition may include a condition that the number of PDUs in the PDU set that have not yet been received at AN 120 is equal to or greater than a threshold number. Alternatively or additionally, the at least one condition may include a condition that the size of the unreceived portion of the PDU set at AN 120 is equal to or greater than a threshold size. For example, if the number of PDUs belonging to the PDU set to be discarded that AN 120 has not yet received is greater than the threshold number, or if the remaining size of the PDU set to be discarded that AN 120 has not yet received is greater than the threshold size, then AN 120 may send a discard notification to UPF 130.

[0064] In an example embodiment, the number and size of thresholds may be determined by AN 120 based on activation requests (205) received from UPF 130 or from PCF 160 via AMF 140 and SMF 150. In another example embodiment, the number and size of thresholds may be determined by AN 120 based on, for example, the specifications of an OAM server. In yet another example embodiment, the number and size of thresholds may be determined by AN 120 based on its own implementation.

[0065] In some example embodiments, the activation request may include at least one of a threshold number and a threshold size for triggering a drop notification transmission of PDUs from AN 120 to UPF 130. For example, the activation request may include a threshold number for the number of PDUs in the PDU set that have not yet been received by AN 120, and / or a threshold size for the number of bytes in the PDU set that have not yet been received by AN 120. In this case, if either the threshold number or the threshold size is exceeded, AN 120 may send a drop notification to UPF 130.

[0066] In some example embodiments, the drop notification may include information for identifying or indicating the affected PDU set. For example, the drop notification may include an identifier (ID) of the Quality of Service (QoS) flow associated with the PDU set (also known as a QoS flow ID or QFI) to identify the affected QoS flow. Alternatively or additionally, the drop notification may include an identifier or sequence number of the PDU set (which may also be referred to as a PDU set sequence number (PSSN)) to identify the affected PDU set.

[0067] Drop notifications can be transmitted directly from AN 120 to UPF 130 via a user plane protocol (e.g., via GTP-U) (225). For example, a drop notification can be transmitted directly from AN 120 to UPF 130 via a GTP PDU on N3 via the user plane (225). As an example, a drop notification can be transmitted via a New Information Element (IE) in the extended header of a GTP PDU (225). In the absence of user data packets or transport PDUs (T-PDUs), AN 120 can generate a UL pseudo-GTP-U packet for such a drop notification.

[0068] In some example embodiments, the drop notification may be transmitted indirectly (225) from AN 120 to UPF 130 via AMF 140 and SMF 150 in the core network. For example, the drop notification may be transmitted from AN 120 to AMF 140 (225), then from AMF 140 to SMF 150 (230), and further from SMF 140 to UPF 130 (235).

[0069] In some example embodiments, AN 120 may receive a deactivation request, for example, from UPF 130, SMF 150, PCF 160, or other application functions of the core network. The deactivation request instructs the access node to cease determining whether to transmit a drop notification to UPF 130 in response to detecting that one or more PDUs belonging to the PDU set have been lost or discarded. AN 120 may then deactivate the transmission of the drop notification.

[0070] The decision to deactivate a discard notification can also be made by UPF 130, SMF 150, PCF 160, or other application functions based on the aforementioned conditions used to determine activation. In some example embodiments, the deactivation request may also include the number and / or size of thresholds for triggering the deactivation of discard notifications from AN 120 to UPF 130. The features associated with activation requests for discard notifications as described above also apply to deactivation requests. Details will be omitted for simplicity.

[0071] After receiving (240) a discard notification from AN 120, UPF 130 discards (245) one or more PDUs belonging to the PDU set at UPF 130. Therefore, UPF 130 can discard PDU(s) associated with the affected PDU set. In some example embodiments, UPF 130 receives the discard notification (240) directly from AN 120. In some other example embodiments, the discard notification may be received (235) by AMF 140, or by SMF 150 (240), and then by UPF 130 (230).

[0072] In some example embodiments, UPF 130 may discard additional PDUs belonging to the PDU set based on a discard notification, wherein the additional PDUs are received after the discard notification is received. For example, if UPF 130 has not yet received the last PDU belonging to the PDU set, UPF 130 may retain or consider information identifying or indicating the affected PDU set to discard any other PDUs from the same PDU set that UPF 130 may receive later. In example embodiments, all remaining PDUs in the PDU set may be received and buffered entirely in UPF 130. In another example embodiment, some PDUs in the PDU set are received and buffered in UPF 130, and other PDUs in the same PDU set have not yet been received by UPF 130. In yet another example embodiment, there may be no buffered PDUs in UPF 130, and all remaining PDUs in the PDU set have not yet been received by UPF 130. Based on the discard notification, the UPF130 can discard any PDU in the PDU set buffered in the UPF130, and / or any PDU in the PDU set received after receiving the discard notification in the UPF130.

[0073] If one or more PDUs belonging to a PDU set are lost or discarded at AN 120, preventing successful decoding of the PDUs, AN 120 can discard buffered PDU(s) associated with the affected PDU set. By using the proposed discard notification solution, PDU(s) already buffered at UPF 130 or to be received later by UPF 130 from the affected PDU set can also be discarded. Therefore, no additional PDU(s) associated with the affected PDU set will be transmitted from UPF 130 to AN 120. This saves transmission network and access network resources and increases network capacity. Furthermore, it saves storage and processing resources for both UPF 130 and AN 120.

[0074] Example Method Figure 3 A flowchart of an example method 300 for an access node according to some example embodiments of the present disclosure is shown. Method 300 can be provided by... Figure 1 The AN 120 implementation is described above. For discussion purposes, references will be made to... Figure 1 Method 300 is described from the perspective of AN 120.

[0075] In box 310, AN 120 receives at least one PDU belonging to the Protocol Data Unit (PDU) set from the user plane function.

[0076] In box 320, based on the detection that one or more PDUs belonging to the PDU set have been lost or discarded, AN 120 determines to transmit a discard notification to the user plane function when at least one condition has been met. The discard notification instructs the user plane function to discard one or more PDUs belonging to the PDU set at the user plane function.

[0077] In some example embodiments, AN 120 may receive an activation request received at the access node. The activation request instructs the access node to determine whether to transmit a drop notification to the user plane function in response to detecting that one or more PDUs belonging to the PDU set have been lost or discarded.

[0078] In some example embodiments, at least one of the following conditions includes: the condition that the last PDU in the PDU set has not yet been received at the access node; the condition that the number of PDUs in the PDU set that have not yet been received at the access node is equal to or greater than a threshold number of PDUs; and the condition that the size of a portion of the PDU set that has not yet been received at the access node is equal to or greater than a threshold size.

[0079] In some example embodiments, the activation request includes at least one of a threshold number and a threshold size for triggering the transmission of a drop notification from the access node to the user plane function.

[0080] In some example embodiments, AN 120 receives a deactivation request. The deactivation request instructs the access node to stop determining whether to transmit a drop notification to the user plane function in response to detecting that one or more PDUs belonging to the PDU set have been lost or discarded. Then, AN 120 deactivates the transmission of the drop notification.

[0081] In some example embodiments, the drop notification includes at least one of the following: an identifier of the quality of service flow associated with the PDU set, and a sequence number of the PDU set.

[0082] In some example embodiments, the activation request is received from the user plane function via a user plane protocol.

[0083] In some example embodiments, the activation request is received from the access and mobility functions in the control plane signaling.

[0084] Figure 4 Examples of embodiments of the present disclosure are shown for use with Figure 1 The flowchart illustrates an example method 400 for the network functions of the core network of a communication network. Method 400 can be derived from, for example... Figure 1 It can be implemented using the network functions of UPF 130, SMF 150 or PCF160.

[0085] At box 410, based on the determination that at least one condition is met, the network function transmits an activation request to the access node. The activation request instructs the access node to determine whether to transmit a drop notification to the user plane function in response to the detection that one or more PDUs belonging to the Protocol Data Unit (PDU) set have been lost or discarded.

[0086] In some example embodiments, at least one condition is associated with at least one of the following: the number of PDUs belonging to the PDU set, protocol data unit set integration processing information, the requirement for successful transmission of all PDUs belonging to the PDU set, memory usage of user plane functions, load status of user plane functions, and media stream characteristics associated with the PDU set.

[0087] In some example embodiments, the activation request includes at least one of a threshold number and a threshold size for triggering the transmission of a drop notification from the access node to the user plane function.

[0088] In some example embodiments, the network function transmits a deactivation request to the access node. The deactivation request instructs the access node to stop determining whether to transmit a drop notification to the user plane function in response to detecting that one or more PDUs belonging to the PDU set have been lost or discarded.

[0089] In some example embodiments, network functions include at least one of user plane functions, session management functions, and policy control functions.

[0090] In some example implementations, the network function receives a PDU set drop notification from the access node and then transmits the PDU set drop notification to the user plane function.

[0091] Figure 5 A flowchart of an example method 500 for user plane functionality according to some example embodiments of the present disclosure is shown. Method 500 can be... Figure 1 The UPF 130 implementation is described above. For discussion purposes, references will be provided. Figure 1 Method 500 is described from the perspective of UPF 130.

[0092] In box 510, UPF 130 receives a discard notification for a set of PDUs, wherein the discard notification instructs the user plane function to discard one or more PDUs belonging to the set of PDUs at the user plane function.

[0093] In box 520, UPF 130 discards one or more PDUs belonging to the PDU set at the user plane function.

[0094] In some example embodiments, UPF 130 discards additional PDUs belonging to the PDU set based on a discard notification, wherein the additional PDUs are received after the discard notification has been received.

[0095] In some example embodiments, the drop notification is received from the access node via a user plane protocol.

[0096] In some example embodiments, the drop notification is received in control plane signaling sent by the session management function.

[0097] In some example embodiments, the drop notification includes at least one of the following: an identifier of the quality of service flow associated with the PDU set, and a sequence number of the PDU set.

[0098] As per the above reference Figures 1 to 2 All operations and features related to AN 120, UPF 130, SMF 150, and PCF 160 are equally applicable to methods 300 to 500 and have similar effects. For the sake of simplicity, details will be omitted.

[0099] Example devices, equipment and media In some example embodiments, a first means capable of performing method 300 (e.g., Figure 1 AN 120 in the document may include components for performing the corresponding operations of method 300. These components may be implemented in any suitable form. For example, the components may be implemented in a circuit system or a software module. The first device may be implemented as or included in... Figure 1 In AN 120.

[0100] In some example embodiments, the first apparatus includes: components for receiving at least one PDU belonging to a set of Protocol Data Units (PDUs) from a user plane function; and components for transmitting a discard notification to the user plane function when at least one condition has been met based on the detection that one or more PDUs belonging to the PDU set have been lost or discarded, wherein the discard notification indicates that the user plane function will discard one or more PDUs belonging to the PDU set at the user plane function.

[0101] In some example embodiments, the first apparatus further includes a component for receiving an activation request, wherein the activation request instructs the access node to determine whether to transmit a drop notification to the user plane function in response to detecting that one or more PDUs belonging to the PDU set have been lost or discarded.

[0102] In some example embodiments, at least one of the following conditions includes: the condition that the last PDU in the PDU set has not yet been received at the access node; the condition that the number of PDUs in the PDU set that have not yet been received at the access node is equal to or greater than a threshold number of PDUs; and the condition that the size of a portion of the PDU set that has not yet been received at the access node is equal to or greater than a threshold size.

[0103] In some example embodiments, the activation request includes at least one of a threshold number and a threshold size for triggering the transmission of a drop notification from the access node to the user plane function.

[0104] In some example embodiments, the first apparatus further includes a component for receiving a deactivation request, wherein the deactivation request instructs the access node to stop determining whether to transmit a drop notification to the user plane function in response to detecting that one or more PDUs belonging to the PDU set have been lost or dropped.

[0105] In some example embodiments, the drop notification includes at least one of the following: an identifier of the quality of service flow associated with the PDU set, and a sequence number of the PDU set.

[0106] In some example embodiments, the activation request is received from the user plane function via a user plane protocol.

[0107] In some example embodiments, the activation request is received from the access and mobility functions in the control plane signaling.

[0108] In some example embodiments, the first device further includes components for performing other operations in some example embodiments of method 300 or AN 120. In some example embodiments, the components include: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause execution of the first device.

[0109] In some example embodiments, a second means capable of performing method 400 (e.g., Figure 1 The UPF 130, AMF140, SMF 150, or PCF 160 in the above may include components for performing the corresponding operations of method 400. These components may be implemented in any suitable form. For example, the components may be implemented in a circuit system or a software module. The second device may be implemented as or included in... Figure 1 Among them, UPF 130, AMF 140, SMF 150 or PCF 160.

[0110] In some example embodiments, the second apparatus includes components for transmitting an activation request to an access node based on determining that at least one condition is met, wherein the activation request instructs the access node to determine whether to transmit a drop notification to the user plane function in response to detecting that one or more PDUs belonging to the Protocol Data Unit (PDU) set have been lost or discarded.

[0111] In some example embodiments, at least one condition is associated with at least one of the following: the number of PDUs belonging to the PDU set, protocol data unit set integration processing information, the requirement for successful transmission of all PDUs belonging to the PDU set, memory usage of user plane functions, load status of user plane functions, and media stream characteristics associated with the PDU set.

[0112] In some example embodiments, the activation request includes at least one of a threshold number and a threshold size for triggering the transmission of a drop notification from the access node to the user plane function.

[0113] In some example embodiments, the second apparatus further includes a component for transmitting a deactivation request to an access node, wherein the deactivation request instructs the access node to stop determining whether to transmit a discard notification to the user plane function in response to detecting that one or more PDUs belonging to the PDU set have been lost or discarded.

[0114] In some example embodiments, the second apparatus further includes: a component for receiving a drop notification for a PDU set from an access node; and a component for transmitting the drop notification for the PDU set to a user plane function.

[0115] In some example embodiments, the second means further includes components for performing other operations in some example embodiments of method 400. In some example embodiments, the components include: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause execution of the second means.

[0116] In some example embodiments, a third means capable of performing method 500 (e.g., Figure 1 The UPF 130 in the document may include components for performing the corresponding operations of method 500. These components may be implemented in any suitable form. For example, the components may be implemented in a circuit system or a software module. The third device may be implemented as or included in... Figure 1 In UPF 130.

[0117] In some example embodiments, the third apparatus includes: a component for receiving a discard notification for a PDU set, wherein the discard notification indicates that a user plane function will discard one or more PDUs belonging to the PDU set at the user plane function; and a component for discarding one or more PDUs belonging to the PDU set at the user plane function.

[0118] In some example embodiments, the third device further includes a component for discarding additional PDUs belonging to the PDU set based on a discard notification, wherein the additional PDUs are received after the discard notification is received.

[0119] In some example embodiments, the drop notification is received from the access node via a user plane protocol.

[0120] In some example embodiments, the drop notification is received in control plane signaling sent by the session management function.

[0121] In some example embodiments, the drop notification includes at least one of the following: an identifier of the quality of service flow associated with the PDU set, and a sequence number of the PDU set.

[0122] In some example embodiments, the third means further includes components for performing other operations in some example embodiments of method 500. In some example embodiments, the components include: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause execution of the third means.

[0123] Figure 6 It is suitable for implementation Figure 1 The diagram shows a simplified block diagram of a computing system 600 that performs one or more core network functions of a communication network 100. The computing system 600 can be provided to implement communication devices, such as... Figure 1 The AN 120, UPF 130, SMF 150, or PCF 160 are shown. As shown, the computing system 600 includes one or more processors 610, one or more memories 620 coupled to the processors 610, and one or more communication modules 640 coupled to the processors 610.

[0124] Communication module 640 is used for bidirectional communication. Communication module 640 has one or more communication interfaces to facilitate communication with one or more other modules or devices. The communication interface can represent any interface required for communication with other network elements. In some example embodiments, communication module 640 may include at least one antenna.

[0125] As a non-limiting example, processor 610 can be any type suitable for a local technology network and can include one or more of the following: general-purpose computer, special-purpose computer, microprocessor, digital signal processor (DSP), and processor based on a multi-core processor architecture. Computing system 600 can have multiple processors, such as application-specific integrated circuit chips that are time-dependent on a clock of a synchronous main processor.

[0126] Memory 620 may include one or more non-volatile memories and one or more volatile memories. Examples of non-volatile memories include, but are not limited to, read-only memory (ROM) 624, electrically programmable read-only memory (EPROM), flash memory, hard disk, optical disc (CD), digital video disc (DVD), optical disc, laser disc, and other magnetic and / or optical storage. Examples of volatile memories include, but are not limited to, random access memory (RAM) 622 and other volatile memories that will not persist for the duration of a power outage.

[0127] Computer program 630 includes computer-executable instructions that are executed by an associated processor 610. The instructions of program 630 may include instructions for performing operations / actions of some example embodiments of this disclosure. Program 630 may be stored in memory (e.g., ROM 624). Processor 610 can perform any suitable actions and processes by loading program 630 into RAM 622.

[0128] The exemplary embodiments of this disclosure can be implemented by program 630, enabling computing system 600 to execute as described in the reference. Figures 1 to 5 Any process discussed in this disclosure. Exemplary embodiments of this disclosure may also be implemented by hardware or by a combination of software and hardware.

[0129] In some example embodiments, program 630 may be tangibly contained in a computer-readable medium, which may be included in computing system 600 (such as in memory 620) or in other storage devices accessible by computing system 600. Computing system 600 may load program 630 from the computer-readable medium into RAM 622 for execution. In some example embodiments, the computer-readable medium may include any type of non-transitory storage medium, such as ROM, EPROM, flash memory, hard disk, CD, DVD, etc. As used herein, the term "non-transitory" is a limitation on the medium itself (i.e., tangible, not tactile), rather than a limitation on the persistence of data storage (e.g., RAM and ROM).

[0130] Figure 7 An example of a computer-readable medium 700 is shown, which may be in the form of a CD, DVD, or other optical storage disc. A program 630 is stored on the computer-readable medium 700.

[0131] Generally, the various embodiments of this disclosure can be implemented in hardware or dedicated circuitry, software, logic, or any combination thereof. Some aspects can be implemented in hardware, while others can be implemented in firmware or software that can be executed by a controller, microprocessor, or other computing device. Although various aspects of the embodiments of this disclosure are illustrated and described as block diagrams, flowcharts, or using some other graphical representation, it should be understood that, as non-limiting examples, the blocks, apparatuses, systems, techniques, or methods described herein can be implemented in hardware, software, firmware, dedicated circuitry or logic, general-purpose hardware or controllers or other computing devices, or some combination thereof.

[0132] Some exemplary embodiments of this disclosure also provide at least one computer program product tangibly stored on a computer-readable medium, such as a non-transitory computer-readable medium. The computer program product includes computer-executable instructions that execute in a device on a target physical or virtual processor, such as those included in a program module, to perform any of the methods described above. Typically, a program module includes routines, programs, libraries, objects, classes, components, data structures, etc., that perform a particular task or implement a particular abstract data type. In various embodiments, the functionality of a program module can be combined or split among program modules as needed. The machine-executable instructions for a program module can execute within a local or distributed device. In a distributed device, the program module can reside in both local and remote storage media.

[0133] Program code used to perform the methods of this disclosure may be written in any combination of one or more programming languages. The program code may be provided to a processor or controller of a general-purpose computer, special-purpose computer, or other programmable data processing apparatus, such that when executed by the processor or controller, the program code causes the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code may be executed entirely on a machine, partially on a machine, as a stand-alone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0134] In the context of this disclosure, computer program code or related 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.

[0135] Computer-readable media can be computer-readable signal media or computer-readable storage media. Computer-readable media can include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatuses, or devices, or any suitable combination thereof. More specific examples of computer-readable storage media will include electrical connections having one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable optical disc read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0136] Furthermore, although operations are described in a specific order, this should not be construed as requiring that such operations be performed in the specific order shown or sequentially, or that all shown operations be performed to achieve the desired result. In some cases, multitasking and parallel processing may be advantageous. Similarly, although several specific implementation details are included in the discussion above, these details should not be construed as limiting the scope of this disclosure, but rather as descriptions of features that may be specific to particular embodiments. Unless explicitly stated otherwise, certain features described in the context of a single embodiment may also be implemented in combination in a single embodiment. Conversely, unless explicitly stated otherwise, various features described in the context of a single embodiment may also be implemented individually or in any suitable sub-combination in multiple embodiments.

[0137] Although this disclosure has been described in language specific to structural features and / or methodological actions, it should be understood that the disclosure as defined in the appended claims is not necessarily limited to the specific features or actions described above. Rather, the specific features and actions described above are disclosed as exemplary forms for implementing the claims.

Claims

1. An access node, comprising: At least one processor; as well as At least one memory storing instructions, which, when executed by the at least one processor, cause the access node to at least: Receive at least one PDU belonging to the Protocol Data Unit (PDU) set from the user plane function; as well as Based on the detection that one or more PDUs belonging to the PDU set have been lost or discarded, and when at least one condition has been met, a discard notification is determined to be transmitted to the user plane function. The discard notification indicates that the user plane function will discard one or more PDUs belonging to the PDU set at the user plane function.

2. The access node according to claim 1, wherein the at least one memory and the at least one processor further enable the access node to: Receive an activation request, wherein the activation request instructs the access node to determine whether to transmit a drop notification to the user plane function in response to detecting that one or more PDUs belonging to the PDU set have been lost or dropped.

3. The access node according to claim 1 or 2, wherein the at least one condition includes at least one of the following: The condition that the last PDU in the PDU set has not yet been received at the access node; The condition that the number of PDUs not yet received at the access node in the PDU set is equal to or greater than the threshold number of PDUs. The condition that the size of a portion of the PDU set that has not yet been received at the access node is equal to or greater than a threshold size.

4. The access node according to claim 2 or 3, wherein the activation request includes at least one of a threshold number and a threshold size for triggering the transmission of the drop notification from the access node to the user plane function.

5. The access node according to any one of claims 1 to 4, wherein the at least one memory and the at least one processor further enable the access node to: Receive a deactivation request, wherein the deactivation request instructs the access node to stop determining whether to transmit a drop notification to the user plane function in response to detecting that one or more PDUs belonging to the PDU set have been lost or dropped; and Deactivate the transmission of the discard notification.

6. The access node according to any one of claims 1 to 5, wherein the drop notification includes at least one of the following: The identifier of the quality of service flow associated with the PDU set, and The sequence number of the PDU set.

7. The access node according to any one of claims 2 to 6, wherein the activation request is received from the user plane function via a user plane protocol.

8. The access node according to any one of claims 2 to 6, wherein the activation request is received from access and mobility functions in control plane signaling.

9. An apparatus comprising: At least one processor; as well as At least one memory storing instructions for network functionality, wherein the instructions, when executed by the at least one processor, cause the device to at least: Based on the determination that at least one condition is met, an activation request is transmitted to the access node, wherein the activation request instructs the access node to determine whether to transmit a drop notification to the user plane function in response to the detection that one or more PDUs belonging to the Protocol Data Unit (PDU) set have been lost or discarded.

10. The apparatus of claim 9, wherein the at least one condition is associated with at least one of the following: The number of PDUs belonging to the PDU set. Protocol data unit sets integrate and process information. The requirement for successful transmission of all PDUs belonging to the PDU set, The memory used for the user plane function The load status of the user plane function, and Media streaming characteristics associated with the PDU set.

11. The apparatus of any one of claims 9 to 10, wherein the activation request includes at least one of a threshold number and a threshold size for triggering the transmission of the drop notification from the access node to the user plane function.

12. The apparatus according to any one of claims 9 to 11, wherein the at least one memory and the at least one processor further cause the apparatus to: A deactivation request is transmitted to the access node, wherein the deactivation request instructs the access node to stop determining whether to transmit a drop notification to the user plane function in response to detecting that one or more PDUs belonging to the PDU set have been lost or dropped.

13. The apparatus according to any one of claims 9 to 12, wherein the network function includes at least one of user plane function, session management function, and policy control function.

14. The apparatus according to any one of claims 9 to 13, wherein the at least one memory and the at least one processor further cause the apparatus to: Receive a drop notification for the PDU set from the access node; and The discard notification for the PDU set is transmitted to the user plane function.

15. An apparatus comprising: At least one processor; as well as At least one memory storing instructions for user plane functions, said instructions, when executed by said at least one processor, cause the device to at least: Receive a drop notification for a PDU set, wherein the drop notification instructs a user plane function to drop one or more PDUs belonging to the PDU set at the user plane function; as well as One or more PDUs belonging to the PDU set are discarded at the user plane function.

16. The apparatus of claim 15, wherein the at least one memory and the at least one processor further enable the apparatus to: Based on the discard notification, other PDUs belonging to the PDU set are discarded, wherein the other PDUs are received after the discard notification is received.

17. The apparatus of any one of claims 15 to 16, wherein the drop notification is received from the access node via a user plane protocol.

18. The apparatus according to any one of claims 15 to 16, wherein the discard notification is received in control plane signaling sent by the session management function.

19. The apparatus according to any one of claims 15 to 18, wherein the discard notification comprises at least one of the following: The identifier of the quality of service flow associated with the PDU set, and The sequence number of the PDU set.

20. A method comprising: Receive at least one PDU belonging to the Protocol Data Unit (PDU) set from the user plane function; as well as Based on the detection that one or more PDUs belonging to the PDU set have been lost or discarded, and when at least one condition has been met, a discard notification is determined to be transmitted to the user plane function. The discard notification indicates that the user plane function will discard one or more PDUs belonging to the PDU set at the user plane function.

21. A method comprising: Based on the determination that at least one condition is met, an activation request is transmitted to the access node, wherein the activation request instructs the access node to determine whether to transmit a drop notification to the user plane function in response to the detection that one or more PDUs belonging to the Protocol Data Unit (PDU) set have been lost or discarded.

22. A method comprising: Receive a drop notification for a PDU set, wherein the drop notification instructs a user plane function to drop one or more PDUs belonging to the PDU set at the user plane function, and One or more PDUs belonging to the PDU set are discarded at the user plane function.

23. A first device, comprising: A component for receiving at least one PDU belonging to a set of Protocol Data Units (PDUs) from a user plane function; as well as A component for determining to transmit a discard notification to the user plane function when at least one condition has been met, based on the detection that one or more PDUs belonging to the PDU set have been lost or discarded. The discard notification indicates that the user plane function will discard one or more PDUs belonging to the PDU set at the user plane function.

24. A second device, comprising: A component for transmitting an activation request to an access node based on determining that at least one condition is met, wherein the activation request instructs the access node to determine whether to transmit a drop notification to the user plane function in response to detecting that one or more PDUs belonging to a set of Protocol Data Units (PDUs) have been lost or dropped.

25. A third device, comprising: A component for receiving a discard notification for a PDU set, wherein the discard notification instructs a user plane function to discard one or more PDUs belonging to the PDU set at the user plane function, and A component for discarding one or more PDUs belonging to the PDU set at the user plane function.

26. A computer-readable medium comprising instructions stored thereon, the instructions being configured to cause a device to perform at least the method of claim 20, the method of claim 21, or the method of claim 22.

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