Target network device, terminal device, and method

Abstract

Exemplary embodiments of the present disclosure relate to a method, an apparatus, and a computer storage medium for communications. The method includes, in a terminal device, determining from a network device at least one of the following parameters associated with a protocol data unit (PDU) set: a first parameter indicating whether all PDUs in the PDU set are required by an application layer; a second parameter indicating whether the PDU set will be discarded if additional PDU sets associated with the PDU set are lost or discarded; a third parameter indicating a discard timer for the PDU set; or a fourth parameter indicating a reordering timer for the PDU set; and processing the PDU set based on the received at least one of the parameters. In this way, packet processing at a PDU set granularity is supported, and PDU set-based processing is also supported. Therefore, communication quality and network performance are improved.

Description

[Technical Field]

[0001] FIELD Exemplary embodiments of the present disclosure relate generally to the field of communications technology, and more particularly to methods, apparatus, and computer-readable media for communications. [Background technology]

[0002] In 3GPP (Third Generation Partnership Project) Release 18 (also referred to as "Rel-18"), extended reality (XR) is gaining increasing attention. XR awareness by terminal devices (also referred to as "UE" or "user equipment") and network devices (also referred to as "gNB") will improve the user experience, increase the capacity of New Radio (NR) systems to support XR services, and reduce the power consumption of terminal devices.

[0003] Due to Internet Protocol (IP) segmentation or other reasons, video frames in XR traffic may arrive at the Radio Access Network (RAN) as a set of Protocol Data Units (PDUs, e.g., multiple IP packets). For XR / media services, a group of packets is used to carry the payload of a PDU set (meaning "a group of PDUs," e.g., a frame, video slice / tile). Packets in such a PDU set are decoded and / or processed as a whole. PDU set-based Quality of Service (QoS) handling is under study and may impact the design of RAN protocols.

[0004] However, in the current 5G system (5GS), a single PDU in a QoS flow is the finest granularity of QoS differentiation in a PDU session. Processing of each data packet in a QoS flow is relatively independent. Therefore, packet processing at a PDU set granularity is not supported. PDU set-based processing is also not supported for RAN and UE. It is also necessary to study how to reflect PDU set information in the Uu interface (air interface). Summary of the Invention [Problem to be solved by the invention]

[0005] In general, embodiments of the present disclosure provide methods, apparatus, and computer storage media for communication, particularly for reporting similarity information between trained / predicted / pre-configured beam information and field / actual beam information. [Means for solving the problem]

[0006] In a first aspect, a method of communication is provided, the method including: receiving, in a terminal device, from a network device, parameters associated with a set of Protocol Data Units (PDUs): a first parameter indicating whether all PDUs in the PDU set are required by an application layer, a second parameter indicating whether the PDU set will be discarded if additional PDU sets associated with the PDU set are lost or discarded, a third parameter indicating a discard timer for the PDU set, or a fourth parameter indicating a reordering timer for the PDU set; and processing the PDU set based on the received at least one of the parameters.

[0007] In a second aspect, a method of communication is provided, the method including: determining, in a network device, at least one of parameters associated with a Protocol Data Unit (PDU) set: a first parameter indicating whether all PDUs in the PDU set are required by an application layer, a second parameter indicating whether the PDU set will be discarded if additional PDU sets associated with the PDU set are lost or discarded, a third parameter indicating a discard timer for the PDU set, or a fourth parameter indicating a reordering timer for the PDU set; and transmitting the at least one of the parameters to a terminal device.

[0008] In some exemplary embodiments, the network device is a source network device from which the terminal device is handed over to a target network device, and the method of the second aspect further includes sending a message for a handover request to the target network device, passing information for preparing the handover to the target network device, the information including at least PDU set-related information, and the PDU set-related information including at least information regarding the first parameter and the second parameter.

[0009] In some exemplary embodiments, the network device is a target network device to which the terminal device is handed over from the source network device, and the method further includes receiving a message for a handover request from the source network device, passing information for preparing the handover at the target network device, the information including at least PDU set-related information, and the PDU set-related information including at least information regarding the first parameter and the second parameter.

[0010] In a third aspect, there is provided a terminal device comprising a processor and a memory storing computer program code, the memory and the computer program code, together with the processor, configured to cause the terminal device to perform the method of the first aspect.

[0011] In a fourth aspect, there is provided a network device comprising a processor and a memory storing computer program code, the memory and the computer program code, together with the processor, configured to cause the network device to perform the method of the second aspect.

[0012] In a fifth aspect, there is provided a computer readable medium storing instructions which, when executed by a processor of a device, cause the device to perform the method of the first or second aspect.

[0013] It should be understood that this Summary of the Invention is not intended to identify key or essential features of the embodiments of the present disclosure, nor to limit the scope of the present disclosure. Other features of the present disclosure will be readily apparent from the following description. [Brief explanation of the drawings]

[0014] The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description of some exemplary embodiments of the present disclosure in the accompanying drawings.

[0015] [Figure 1] FIG. 1 illustrates an exemplary communication system in which some embodiments of the present disclosure may be implemented.

[0016] [Figure 2] 1 is an exemplary signaling chart in accordance with some exemplary embodiments of the present disclosure.

[0017] [Figure 3A] FIG. 2 illustrates a first exemplary PDCP data PDU format, in accordance with some exemplary embodiments of the present disclosure.

[0018] [Figure 3B] FIG. 10 illustrates a second exemplary PDCP data PDU format, in accordance with some exemplary embodiments of the present disclosure.

[0019] [Figure 3C] FIG. 10 illustrates a third exemplary PDCP data PDU format, in accordance with some exemplary embodiments of the present disclosure.

[0020] [Figure 3D] FIG. 10 illustrates a fourth exemplary PDCP data PDU format, in accordance with some exemplary embodiments of the present disclosure.

[0021] [Figure 3E] A diagram showing a fifth exemplary PDCP data PDU format in accordance with some exemplary embodiments of the present disclosure.

[0022] [Figure 3F] A diagram showing a sixth exemplary PDCP data PDU format in accordance with some exemplary embodiments of the present disclosure.

[0023] [Figure 4] FIG. 2 is an example signaling diagram of a communication process in accordance with some example embodiments of the present disclosure.

[0024] [Figure 5] 1 is a flowchart of an exemplary method implemented in a terminal device, according to some embodiments of the present disclosure.

[0025] [Figure 6] 1 is a flowchart of an exemplary method implemented in a network device, according to some embodiments of the present disclosure.

[0026] [Figure 7] FIG. 1 is a schematic block diagram of an apparatus suitable for implementing embodiments of the present disclosure.

[0027] In the drawings, the same or similar reference numbers represent the same or similar elements.

[0028] Throughout this document, reference may be made to the following defined terms.

[0029] 3GPP 3rd Generation Partnership Project

[0030] NR New Radio Access

[0031] DCI Downlink Control Information

[0032] XR Extended Reality

[0033] PDCCH Physical Downlink Control CHannel

[0034] MACCE MAC Control Element

[0035] RRC Radio Resource Control

[0036] PSDB PDU Set Delay Budget

[0037] PSER PDU Set Error Rate DETAILED DESCRIPTION OF THE INVENTION

[0038] The principles of the present disclosure will now be described with reference to some exemplary embodiments. It should be understood that these embodiments are provided for illustrative purposes only to aid those skilled in the art in understanding and practicing the present disclosure, and do not imply any limitation on the scope of the present disclosure. The embodiments described herein can be implemented in various ways different from those described below.

[0039] In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains.

[0040] 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 do not necessarily mean that each embodiment includes that particular feature, structure, or characteristic. Moreover, such 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 of ordinary skill in the art to affect such feature, structure, or characteristic in connection with other embodiments, whether or not explicitly described.

[0041] While the terms "first," "second," and the like may be used herein to describe various elements, it should be understood that these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, a first element may be termed a second element, and similarly, a second element may 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 terms.

[0042] The terminology used herein is used only for the purpose of describing particular embodiments and is not intended to limit example embodiments. As used herein, the singular forms "a," "an," and "said" include the plural forms unless the context clearly indicates otherwise. It should be further understood that, as used herein, the terms "comprise," "include," "have," "comprise," "comprises," and / or "have" 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.

[0043] In some instances, values, procedures, or devices are referred to as "best," "lowest," "highest," "minimum," "maximum," etc. It should be understood that such descriptions are intended to illustrate that selections may be made from among many functional alternatives used, and that such selections are not necessarily better, smaller, higher, or otherwise more preferred than other selections.

[0044] As used herein, the term "communication network" refers to a network conforming to any appropriate 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 implemented in accordance with any appropriate generation of 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), 5.5G, 5G-Advanced network, or sixth generation (6G) communication protocols, and / or any other protocol now known or developed in the future. Embodiments of the present disclosure may be applied to various communication systems. In view of the rapid development of communications, there will naturally be future types of communications technologies and systems in which the present disclosure can be embodied, which should not be considered to limit the scope of the present disclosure to only the aforementioned systems.

[0045] As used herein, the term "terminal device" means any device with wireless or wired communication capabilities. Examples of terminal devices include User Equipment (UE), personal computers, desktops, mobile phones, cellular phones, smartphones, Personal Digital Assistants (PDAs), portable computers, tablets, wearable devices, Internet of Things (IoT) devices, Ultra-reliable and Low Latency Communication (URLLC) devices, Internet of Everything (IoE) devices, Machine Type Communication (MTC) devices, vehicle-mounted devices for V2X communications where X stands for pedestrian, vehicle, or infrastructure / network, devices for Integrated Access and Backhaul (IAB), satellite- or airborne vehicles in a Non-terrestrial network (NTN) including High Altitude Platforms (HAPs) including satellites and Unmanned Aircraft Systems (UASs), Augmented Reality (AR), Mixed Reality (MR), and other technologies. This includes, but is not limited to, extended reality (XR) devices that include different types of reality, such as virtual reality (VR), unmanned aerial vehicles (UAVs), which are aircraft without a human pilot and are commonly referred to as drones, devices on high-speed trains (HSTs), image capture devices such as digital cameras, sensors, gaming devices, music storage and playback devices, or internet devices that enable wireless or wired internet access and browsing.A "terminal device" may also have multicast / broadcast capabilities to support public safety, mission-critical, V2X applications, transparent IPv4 / IPv6 multicast distribution, IPTV, smart TV, wireless services, wireless software distribution, group communication, and IoT applications. It may also incorporate one or more Subscriber Identity Modules (SIMs), known as multi-SIMs. The term "terminal device" can be used interchangeably with UE, mobile station, subscriber equipment, mobile terminal, user terminal, or wireless device.

[0046] The term "network device" as used herein means 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 satellite, an Unmanned Aerial System (UAS) platform, a Node B (Node B or NB), an evolved Node B (eNodeB or eNB), a next generation Node B (gNB), a Transmission Reception Point (TRP), a Remote Radio Unit (RRU), a Radio Head (RH), a Remote Radio Head (RRH), an IAB node, a low-power node such as a femto node or a pico node, a Reconfigurable Intelligent Surface (RIS), etc.

[0047] Communications described herein may conform to any suitable standard, including, but not limited to, New Radio Access (NR), Long Term Evolution (LTE), LTE-Evolution, LTE-Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA), Code Division Multiple Access (CDMA), cdma2000, Global System for Mobile Communications (GSM), etc. Furthermore, communications may be performed in accordance with any generation of communications protocols now known or developed in the future. Examples of communication protocols include, but are not limited to, first generation (1G), second generation (2G), 2.5G, 2.85G, third generation (3G), fourth generation (4G), 4.5G, fifth generation (5G), and sixth generation (6G) communication protocols. The techniques described herein may be used for the wireless networks and technologies mentioned above, as well as other wireless networks and technologies. Embodiments of the present disclosure may be performed in accordance with any generation of communication protocols now known or developed in the future.Examples of communication 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, fifth generation (5G) communication protocols, 5.5G, 5G-Advanced networks, or sixth generation (6G) networks.

[0048] A terminal device or a network device may have artificial intelligence (AI) or machine learning capabilities, which generally include a model trained from a large amount of data collected for a specific function and can be used to predict some information.

[0049] The terminal device or network device may operate on several frequency ranges, such as FR1 (410 MHz to 7125 MHz), FR2 (24.25 GHz to 71 GHz), frequency bands greater than 100 GHz, and Terahertz (THz). It can also operate on licensed, unlicensed, and shared spectrum. The terminal device may have two or more connections with the network device under a Multi-Radio Dual Connectivity (MR-DC) application scenario. The terminal device or network device can operate in full duplex, flexible duplex, and cross-division duplex modes.

[0050] Embodiments of the present disclosure may be implemented in test equipment such as, for example, a signal generator, a signal analyzer, a spectrum analyzer, a network analyzer, a test terminal device, a test network device, or a channel emulator.

[0051] Embodiments of the present disclosure may be performed in accordance with any currently known or future developed 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, 5.5G, 5G-Advanced networks, or sixth generation (6G) networks.

[0052] 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 yet another example, a circuit may be any portion of a hardware processor with software, including a digital signal processor, software, and one or more memories, that cooperate to cause a device, such as a terminal device or a network device, to perform various functions. In yet another example, a circuit may be a hardware circuit and / or a processor, such as a microprocessor or portion thereof, that requires software / firmware for operation, although software may not be present if not necessary for operation. As used herein, the term "circuitry" also includes an implementation of a hardware circuit or one or more processors only, or a hardware circuit or portion of one or more processors and its (or their) accompanying software and / or firmware.

[0053] As used herein, the singular forms "a," "an," and "said" include the plural forms unless the context clearly indicates otherwise. The term "comprises" and variations thereof should be understood as open-ended terms meaning "including, but not limited to." The term "based on" should be understood as "based at least in part on." The terms "one embodiment" and "embodiment" should be understood as "at least one embodiment." The term "another embodiment" should be understood as "at least one other embodiment." Terms such as "first," "second," etc. may refer to different or the same object. The following may include other explicit and implicit definitions.

[0054] In some instances, values, procedures, or devices are referred to as "best," "lowest," "highest," "minimum," "maximum," etc. It should be understood that such descriptions are intended to illustrate that selections may be made from among many functional alternatives used, and that such selections are not necessarily better, smaller, higher, or otherwise more preferred than other selections.

[0055] In an exemplary PDCP data PDU format according to conventional schemes in the art, the PDCP data PDU format is N octets long and includes a 12-bit "PDCP SN" field. Specifically, the first octet includes, from left to right, a "D / C" field, three "R" (for "reserved") fields, and the first four bits of the "PDCP SN" field. The second octet includes the remaining eight bits of the "PDCP SN" field. The remaining octets in the first format are used to store data.

[0056] In another exemplary PDCP data PDU format according to conventional schemes in the art, the PDCP data PDU format is also N octets long and includes an 18-bit "PDCP SN" field. Specifically, the first octet includes, from left to right, a "D / C" field, five "R" fields, and the first two bits of the "PDCP SN" field. The second and third octets include the remaining 16 bits of the "PDCP SN" field, with each field containing 8 bits. The remaining octets in the format are used to store data.

[0057] In conventional systems, as mentioned above, a PDCP data PDU format with a 12-bit PDCP SN and a PDCP data PDU format with an 18-bit PDCP SN are defined. A transmitting PDCP entity should maintain a discard timer to discard a PDCP service data unit (SDU) when certain conditions are met. This timer is configured only for the data radio bearer (DRB). The timer's duration is configured by higher layers. At the transmitter (or, in other words, at the transmitting PDCP entity), a new timer is started upon reception of an SDU from higher layers. When the discardTimer expires for a PDCP SDU, or when successful delivery of the PDCP SDU is confirmed by a PDCP status report, the transmitting PDCP entity should discard the PDCP SDU along with the corresponding PDCP data PDU. If the corresponding PDCP data PDU has already been submitted to lower layers, discarding is indicated to the lower layers. For SRB, if the upper layer requests the discarding of PDCP SDUs, the PDCP entity should discard all stored PDCP SDUs and PDCP PDUs.

[0058] At the same time, the receiving PDCP entity should maintain a reordering timer (e.g., with the name "t-Reordering") for reordering the PDUs received at the receiving PDCP entity. The duration of the timer is configured by higher layers, except in the case of New Radio (NR) sidelink communication or sidelink Signaling Radio Bearer 4 (SRB4). In the case of NR sidelink communication or sidelink SRB4, the t-Reordering timer is determined by the terminal device implementation. This timer is used to detect PDCP data PDU loss. If the t-Reordering timer is running, no additional t-Reordering timers should be started; i.e., at a given time, only one t-Reordering timer is running per receiving PDCP entity.

[0059] In an exemplary signaling flow of a handover process according to a conventional technique in the art, a source gNB (source network device) issues a Handover Request message to a target gNB (target network device), passing a transparent RRC container with information necessary to prepare a handover at the target gNB. The information includes at least a target cell ID, KgNB*, a C-RNTI of the terminal device at the source network device, an RRM configuration including the terminal device's inactive time, a basic access strum (AS) configuration including antenna info (short for "information") and DL carrier frequency, a current QoS flow-to-DRB mapping rule applied to the terminal device, SIB1 from the source network device, the terminal device's capabilities for different radio access technologies (RATs), and measurement information reported by the terminal device, including PDU session-related information and, if possible, beam-related information. The PDU session-related information may include slice information and a QoS flow-level QoS profile. The source network device may also request a Dual Active Protocol Stack (DAPS) handover for one or more DRBs.

[0060] For DRBs configured with DAPS, the source gNB sends an EARLY STATUS TRANSFER message. The DL COUNT value conveyed in the EARLY STATUS TRANSFER message indicates the PDCP SN and Hyper Frame Number (HFN) of the first PDCP SDU that the source gNB will transfer to the target gNB. The source gNB does not stop allocating SNs to downlink PDCP SDUs until it sends an SN STATUS TRANSFER message to the target gNB in ​​step 8b.

[0061] In the U-plane process for handover, for Radio Link Control - Acknowledgement (RLC-AM) bearers, the PDCP SN is maintained on a per DRB basis, and the source gNB informs the target gNB about the next DL PDCP SN to assign to packets (from the source gNB or from the UPF) that do not yet have a PDCP sequence number. For security synchronization, the HFN is also maintained, and the source gNB provides the target gNB with one reference HFN for the UL and one reference HFN for the DL, i.e., the HFN and the corresponding SN. Furthermore, for RLC-UM bearers, the PDCP SN and HFN are reset at the target gNB unless a DAPS handover is configured for the bearer.

[0062] In particular, for DAPS handover, both downlink and uplink operations are performed at PDU / SDU granularity.

[0063] In some communication systems, an application layer instance can generate information units that can be used by another application layer instance, for example to construct usable information; an example of such an information unit may be a video frame. Depending on its size and the Maximum Transmission Unit (MTU) of the transport network, the information unit may need to be segmented and forwarded in multiple transport units, for example, multiple IP packets. If all segments are received, the receiving application layer instance uses the information unit. Therefore, the Quality of Experience (QoE) depends on the reception of the information unit (rather than the individual segments that make up the information unit). Therefore, a forwarding action described by QoS parameters needs to be associated with the information unit.

[0064] As a result, the conventional system described above may not provide good performance. To achieve good performance, for XR / media services, a group of packets is used to carry the payload of a PDU set (e.g., a frame, a video slice / tile). At the media layer, packets in such a PDU set are decoded and / or processed as a whole. For example, a frame / video slice may be decoded only if all or a certain number of packets carrying the frame / video slice are successfully delivered. For example, a frame in a Group of Pictures (GOP) can be decoded by a client only if all frames on which it depends are successfully received. Therefore, groups of packets in a PDU set have inherent dependencies with each other at the media layer. Without considering such dependencies between packets in a PDU set, 5GS may perform scheduling inefficiently. For example, 5GS may randomly drop packets, potentially wasting radio resources by attempting to deliver other packets from the same PDU set that are useless to the client.

[0065] In view of the above problems, this specification introduces a method, an apparatus, and a computer-readable medium for communication to achieve better communication quality and network performance, particularly for XR services. Such solutions are described in detail below with reference to Figures 1 to 7.

[0066] 1 illustrates an exemplary communication system 100 in which some embodiments of the present disclosure may be implemented. The communication system 100, which is part of a communication network, includes network devices 110-1, 110-2, and a terminal device 120. Hereinafter, the network device 110-1 may be referred to as a first network device (or a "source network device"), and the network device 110-2 may be referred to as a second network device (or a "target network device"). The network devices 110-1 and 110-2 may be collectively referred to as "network device 110" or "gNB 110," or individually referred to as "network device 110" or "gNB 110."

[0067] 1, network device 110 provides a coverage area that includes cell 101, and terminal device 120 camps in cell 101 and is served by network device 110-1. Network device 110-2 has a coverage area that includes cell 102. In other words, network device 110-1 provides network connectivity to terminal device 120.

[0068] In system 100, the link from network device 110 to terminal device 120 is referred to as the downlink (DL), and the link from terminal device 120 to network device 110 is referred to as the uplink (UL). In the downlink, network device 110 is the transmit (TX) device (or transmitter) and terminal device 120 is the receive (RX) device (or receiver). In the uplink, terminal device 120 is the transmit TX device (or transmitter) and network device 110 is the RX device (or receiver). It should be understood that network device 110 may provide one or more serving cells. In some embodiments, network device 110 can provide multiple cells.

[0069] Network device 110-1 may provide a service to terminal device 120, and network device 110-1 and terminal device 120 may communicate data and control information with each other. In other words, network device 110-1 is a serving network device for terminal device 120.

[0070] Communications in communication system 100 may conform to any suitable standard, including, but not limited to, Long Term Evolution (LTE), 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 communication protocols. Examples of communication 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, fifth generation (5G), 5.5G, 5G-Advanced networks, or sixth generation (6G) communication protocols.

[0071] It should be understood that the number of devices and their connectivity and types shown in Figure 1 are provided for illustrative purposes only and do not imply any limitations. Communication system 100 may include any appropriate number of network devices and terminal devices suitable for implementing embodiments of the present disclosure.

[0072] The following points should be noted:

[0073] The term "PDU set" in this disclosure means, for example, that a PDU set consists of one or more PDUs carrying the payload of one information unit (e.g., a frame or video slice for XRM services used in 3gpp TR26.926

[27] ) generated at the application level. In some implementations, all PDUs in a PDU set are required by the application layer to use the corresponding information unit. In other implementations, the application layer can recover part or all of the information unit even if some PDUs are missing.

[0074] In this disclosure, the term "data burst" refers to a set of data including, for example, multiple PDUs generated and transmitted by an application within a short period of time. Note that a data burst can consist of one or more PDU sets.

[0075] The term "PSDB" in this disclosure refers to a PDU Set Delay Budget (PSDB) that defines an upper limit on the time a PDU set may be delayed between, for example, the terminal device 120 and the N6 termination point in the User-Plane Function (UPF). The PSDB applies to DL PDU sets received by the UPF via the N6 interface and to UL PDU sets transmitted by the terminal device 120.

[0076] The term "PSER" in this disclosure refers, for example, to the PDU Set Error Rate (PSER), which defines an upper bound on the proportion of PDU sets (e.g., a set of IP packets constituting a PDU set) processed by a sender of a link layer protocol (e.g., Radio Link Access (RLC) in a RAN of 3GPP access) where not all PDUs in the PDU set are successfully delivered by a corresponding receiver to a higher layer (e.g., PDCP in a RAN of 3GPP access). Thus, the PSER defines an upper bound on the non-congestion-related packet loss rate. The purpose of the PSER is to enable appropriate link layer protocol configuration (e.g., RLC and Hybrid Automatic Repeat Request (HARQ) in a RAN of 3GPP access).

[0077] 2 shows an example signaling diagram illustrating a communication process 200 according to some example embodiments of the present disclosure. For illustrative purposes only, the communication process 200 will be described with reference to FIG. 1. The communication process 200 may involve a terminal device 120 and a network device 110.

[0078] In some exemplary embodiments, the network device 110 determines at least one of the following parameters associated with a Protocol Data Unit (PDU) set: a first parameter indicating whether all PDUs in the PDU set are required by the application layer; a second parameter indicating whether the PDU set will be discarded if additional PDU sets associated with the PDU set are lost or discarded; a third parameter indicating a discard timer for the PDU set; or a fourth parameter indicating a reordering timer for the PDU set.

[0079] For example, for the control plane, the network device 110 may determine 210 at least one of the following parameters for the terminal device 120 via RRC signaling, as shown in FIG.

[0080] ● Whether all PDUs belonging to a PDU set are required: Based on this parameter, the receiving PDCP entity can decide whether to discard all PDUs belonging to a PDU set if at least one PDU of the set is lost.

[0081] If a high priority (or associated) PDU set is lost / discarded, whether other PDU sets associated with this PDU set should be discarded or not.

[0082] ● PDU set discard timer (e.g. with the name "discardTimer"): This timer is set for the DRB only. At the first reception of a PDU of a PDCP set from the upper layer in the transmitting PDCP entity, a new PDCP set discard timer is started. If this timer expires, the terminal device 120 discards all PDUs belonging to the corresponding PDU set and / or all PDUs of other PDU sets associated with this PDU set. All PDUs in the same PDU set share the same PDU set discard timer.

[0083] ● PDU Set Reordering Timer (eg, with the name "t-Reordering"): This timer is set only for the DRB. This timer is used to detect the loss of PDCP data PDUs belonging to the corresponding PDU set.

[0084] Additionally, in some exemplary embodiments, network device 110 transmits at least one of the parameters to terminal device 120 .

[0085] For example, for the control plane, the network device 110 may transmit (220) at least one of the parameters (denoted as 201 in FIG. 2) to the terminal device 120 (e.g., via RRC signaling), as shown in FIG. 2.

[0086] On the other side of the communication, terminal device 120 receives 222 at least one parameter 201. The received parameters can be used to configure such parameters in terminal device 120.

[0087] Furthermore, in some exemplary embodiments, terminal device 120 processes the PDU set based on the received at least one of the parameters 201 .

[0088] For example, the terminal device 120 may process 230 the PDU set (eg, drop / discard the PDU set) based on the received at least one of the parameters 201 .

[0089] Several fields may be defined in the PDCP data PDU to facilitate processing of PDU sets by terminal device 120. In some example embodiments, packets from higher layers are organized in PDU sets at the PDCP layer, and PDU set information is transmitted in-band in the PDCP header of each PDU in the PDU set.

[0090] For example, as can be seen from the examples shown in Figures 3A-3F, packets from higher layers are organized in PDU sets at the PDCP layer, and PDU set information is transmitted in-band in the PDCP header of each PDU in the PDU set, as will be described in more detail with reference to Figures 3A-3F.

[0091] FIG. 3A illustrates an exemplary PDCP data PDU format (hereinafter referred to as the "first format") according to some exemplary embodiments of the present disclosure.

[0092] In some exemplary embodiments, the header of a PDCP data PDU defines at least one of the following fields: a first field indicating the serial number (SN) of the PDU set to which the PDCP data PDU belongs; a second field indicating whether the PDCP data PDU is the first PDU of the PDU set to which it belongs; or a third field indicating whether the PDCP data PDU is the last PDU of the PDU set to which it belongs.

[0093] For example, a PDCP data PDU format with a 12-bit PDCP SN (for a PDU set) is shown in Figure 3A. According to the first format, at least one of the following fields may be defined in the header of the PDCP data PDU:

[0094] "PDU set SN" field: This field indicates the SN of the PDU set to which the PDCP data PDU belongs.

[0095] "Start Indication" field: This field indicates whether the PDCP Data PDU is the first PDU of the PDU set to which it belongs. If the value of this field is set to "0", it indicates that the PDCP Data PDU is not the first PDU of the PDU set to which it belongs. If the value of this field is set to "1", it indicates that the PDCP Data PDU is the first PDU of the PDU set to which it belongs.

[0096] "End Indication" field: This field indicates whether this PDCP Data PDU is the last PDU of the PDU set to which it belongs. If the value of this field is set to "0", it indicates that this PDCP Data PDU is not the last PDU of the PDU set to which it belongs. If the value of this field is set to "1", it indicates that this PDCP Data PDU is not the last PDU of the PDU set to which it belongs.

[0097] In some exemplary embodiments, the second and third fields each occupy one bit in the PDCP header. For example, as shown in FIG. 3A, the "start indication" and "end indication" fields may each occupy one reserved bit in the PDCP header.

[0098] Additionally or alternatively, the length of the "PDU Set SN" field may be one octet, i.e., eight bits, as shown in FIG. 3A.

[0099] FIG. 3B illustrates another exemplary PDCP data PDU format (hereinafter referred to as the "second format") according to some exemplary embodiments of the present disclosure.

[0100] In some exemplary embodiments, the header of a PDCP data PDU defines at least one of the following fields: a first field indicating the serial number (SN) of the PDU set to which the PDCP data PDU belongs; a second field indicating whether the PDCP data PDU is the first PDU of the PDU set to which it belongs; or a third field indicating whether the PDCP data PDU is the last PDU of the PDU set to which it belongs.

[0101] For example, a PDCP data PDU format with an 18-bit PDCP SN (for PDU set) is shown in Figure 3B. According to the second format, at least one field among the "PDU Set SN" field, the "Start Indicator" field, and the "End Indicator" field should be defined in the header of the PDCP data PDU.

[0102] Similar to the example shown in Figure 3A, in the example shown in Figure 3B, the second field ("Start Indicator" field) and the third field ("End Indicator" field) may each use one reserved bit in the PDCP header. Additionally or alternatively, the length of the "PDU Set SN" field may be one octet, i.e., eight bits, as shown in Figure 3B.

[0103] 3C illustrates an exemplary PDCP data PDU format (hereinafter referred to as the "third format") according to some exemplary embodiments of the present disclosure. For illustrative purposes only, the third format will be described with reference to FIG. 3A.

[0104] In some exemplary embodiments, the header of the PDCP data PDU further defines at least one of the following fields: a fourth field indicating the SN of another PDU set, where the PDU set to which the PDCP data PDU belongs is associated with the PDU set identified by the fourth field; a fifth field indicating whether the fourth field is present in the header of the PDCP data PDU; or a sixth field indicating the importance or priority of the PDU set.

[0105] For example, a PDCP data PDU format with a 12-bit PDCP SN (for a PDU set) is shown in Figure 3C. According to the third format, at least one of the following fields may be further defined in the header of the PDCP data PDU:

[0106] "Correlation PDU Set SN" field (optional): This field indicates the SN of another PDU set, and the PDU set to which this PDCP data PDU belongs is associated with the PDU set identified by this field. For example, if at least one PDU of the PDU set indicated by the "Correlation PDU Set SN" field is lost / discarded, the PDU set to which this PDCP data PDU belongs should also be discarded / dropped.

[0107] "T" field (optional): This field indicates whether the "Correlated PDU Set SN" field is present in the PDCP header. If the value of the "T" field is set to 0, it indicates that the "Correlated PDU Set SN" field is not present in the PDCP header. If the value of the "T" field is set to 1, it indicates that the "Correlated PDU Set SN" field is present in the PDCP header.

[0108] "PDU Set Importance Level Information" field (or priority or PDU Set Type, optional): This field contains the importance or priority information of the PDU set. For example, the importance level (or priority) of the PDU set corresponding to an I-frame (short for "Independent frame," which is a single frame of digital content that the compressor examines independently of the frames before and after it and stores all the data necessary to display that frame) and a P-frame (short for "Predicted frame," which contains only the image changes from the previous frame) are different. The importance level (or priority) of the PDU set corresponding to the Base Layer (BL) and the Enhanced Layer (EL) are different, etc.

[0109] In some exemplary embodiments, the fifth field occupies one bit in the PDCP header, and in response to the fifth field indicating that the fourth field is present in the PDCP header, the fourth field is newly added to the PDCP header.

[0110] For example, the fifth field (the "T" field) reuses a reserved bit in the PDCP header. A "T" field set to 1 may indicate that the "Correlated PDU Set SN" field is present in the PDCP header, and a "T" field set to 0 may indicate that the "Correlated PDU Set SN" field is present in the PDCP header. In this case, the fourth field (i.e., the "Correlated PDU Set SN" field) is newly added to the PDCP header in response to the "T" field indicating that the fourth field is present in the PDCP header (i.e., the "T" field is set to 1).

[0111] 3D illustrates another exemplary PDCP data PDU format (hereinafter referred to as the "fourth format") according to some exemplary embodiments of the present disclosure. For illustrative purposes only, the fourth format will be described with reference to FIG. 3B.

[0112] For example, a PDCP data PDU format with an 18-bit PDCP SN (for a PDU set) is shown in Figure 3D. According to the fourth format, at least one of the following fields may be defined in the header of the PDCP data PDU: a "Correlated PDU Set SN" field (optional), a "T" field (optional), and a "PDU Set Importance Level Information" field.

[0113] In some exemplary embodiments, the fifth field occupies one bit in the PDCP header, and in response to the fifth field indicating that the fourth field is present in the PDCP header, the fourth field is newly added to the PDCP header.

[0114] For example, the fifth field (the "T" field) reuses a reserved bit in the PDCP header. A "T" field set to 1 may indicate that the "Correlated PDU Set SN" field is present in the PDCP header, and a "T" field set to 0 may indicate that the "Correlated PDU Set SN" field is present in the PDCP header. In this case, the fourth field (i.e., the "Correlated PDU Set SN" field) is newly added to the PDCP header in response to the "T" field indicating that the fourth field is present in the PDCP header (i.e., the "T" field is set to 1).

[0115] 3E illustrates an example PDCP data PDU format (hereinafter referred to as the "fifth format") according to some example embodiments of the present disclosure. For illustrative purposes only, the fifth format will be described with reference to FIG. 3A.

[0116] For example, a PDCP data PDU format with a 12-bit PDCP SN (for a PDU set) is shown in Figure 3E. According to the fifth format, compared with the first format, an "Imp" field indicating PDU set importance level information is further defined in the header of the PDCP data PDU. As mentioned above, this field contains the importance or priority information of the PDU set. For example, the importance levels (or priorities) of PDU sets corresponding to I frames and P frames are different; the importance levels (or priorities) of PDU sets corresponding to BL layers and EL layers are different; etc.

[0117] In some exemplary embodiments, the sixth field uses at least one bit in the PDCP header.

[0118] For example, as shown in FIG. 3E, the sixth field (the "PDU Set Importance Level Information" field, or simply the "Imp" field, as shown in FIG. 3E) reuses reserved bits in the PDCP header, as shown in FIG. 3A.

[0119] 3F illustrates another exemplary PDCP data PDU format (hereinafter referred to as the "sixth format") according to some exemplary embodiments of the present disclosure. For illustrative purposes only, the sixth format will be described with reference to FIG. 3B.

[0120] For example, a PDCP data PDU format with an 18-bit PDCP SN (for a PDU set) is shown in Figure 3F. According to the sixth format, compared with the second format, an "Imp" field indicating PDU set importance level information is further defined in the header of the PDCP data PDU. As mentioned above, this field contains the importance or priority information of the PDU set. For example, the importance levels (or priorities) of PDU sets corresponding to I frames and P frames are different; the importance levels (or priorities) of PDU sets corresponding to BL layers and EL layers are different; etc.

[0121] In some exemplary embodiments, the sixth field uses at least one bit in the PDCP header.

[0122] For example, the sixth field (the "PDU Set Importance Level Information" field, or simply the "Imp" field, as shown in FIG. 3E) reuses reserved bits in the PDCP header.

[0123] In some exemplary embodiments, the terminal device further determines a range of counts or PDCP SNs belonging to the PDU set from a first count or first PDCP SN, which is a count or PDCP SN of PDCP data PDUs with the second field set to 1, to a second count or second PDCP SN, which is a count or PDCP SN of PDCP data PDUs with the third field set to 1, and determines whether the PDCP set has lost at least one PDU based on information about the PDU set SN, the count or PDCP SN, the second field, and the third field.

[0124] For example, in the examples shown in Figures 3A to 3F, the range of COUNT (or PDCP SN) belonging to a PDU set is [COUNT (or PDCP SN) of PDCP data PDUs whose start indication field is set to 1, COUNT (or PDCP SN) of PDCP data PDUs whose end indication field is set to 1]. The terminal device 120 and / or network device 110 can determine whether any PDUs in the PDCP set have been lost according to the "PDU set SN", COUNT (or "PDCP SN"), "start indication" and "end indication" fields.

[0125] In this case, if no PDCP data PDUs with the "start indication" field set to 1 or the "end indication" field set to 1 are received for a PDU set, it can be inferred that the PDCP set has lost at least one PDU.

[0126] Furthermore, when a PDCP data PDU with the "start indication" field set to 1 and a PDCP data PDU with the "end indication" field set to 1 are received for a PDU set, the PDCP receiving entity determines the COUNT (or PDCP SN) range of the PDU set based on these PDCP data PDUs. If any PDCP PDU within this range is lost, the receiving PDCP entity can determine that the PDU set has lost at least one PDU.

[0127] Thus, based on the PDCP data PDU structure (e.g., as shown in Figures 3A-3F), the PDCP SN (or COUNT) values ​​are conventionally sequential, and existing COUNT-based procedures (e.g., encryption / integrity protection / reordering, etc.) can be reused. At the same time, PDU set-related procedures, such as PDU set-based discarding and determining whether any PDUs in a PDU set have been lost, may be performed based on conventional COUNT-based procedures.

[0128] In some example embodiments, upon first reception of a PDCP SDU belonging to a PDU set from a higher layer, the transmitting PDCP entity (e.g., in terminal device 120) starts a discard timer associated with that PDU set, and if the discard timer expires for that SDU set, discards the PDUs and / or SDUs belonging to the corresponding PDU set and / or PDUs and / or SDUs of other PDU sets associated with that PDU set, where PDUs within the same PDU set share the same discard timer.

[0129] For example, in a PDU set discard timer-based drop / discard scenario, a PDU set discard timer (e.g., with the name "discardTimer") is defined as a timer that is set only for the DRB. All PDUs in the same PDU set share the same PDU set discard timer. Upon the first reception of a PDCP SDU belonging to a PDCP set from higher layers, the transmitting PDCP entity (e.g., in the terminal device 120) should start the PDU set discard timer associated with this PDU set (if configured). If the PDU set discard timer expires for a PDU set, the transmitting PDCP entity should discard all PDUs / SDUs belonging to the corresponding PDU set and / or all PDUs / SDUs of other PDU sets associated with this PDU set. If the corresponding PDCP data PDUs have already been submitted to lower layers, the discard is indicated to the lower layers. For example, if PDU set N (the PDU set with set index "N") is discarded, the transmitting PDCP entity should also discard PDU sets whose "Correlated PDU Set SN" field is equal to N.

[0130] There are two alternatives for buffering the data belonging to a PDU set: one way is that all PDCP SDUs of a PDU set are delivered to upper layers only when all PDUs belonging to the PDU set have been received; otherwise, the data of the PDU set should be stored in the receive buffer for reordering; the other way is that only out-of-order data should be stored in the receive buffer as usual.

[0131] In some example embodiments, upon first reception of a PDU belonging to a PDU set from a lower layer, the receiving PDCP entity (e.g., in terminal device 120) starts a reordering timer associated with that PDU set, and, if the reordering timer expires for that SDU set, discards the PDUs and / or SDUs belonging to the corresponding PDU set and / or PDUs and / or SDUs of other PDU sets associated with that PDU set, where PDUs within the same PDU set share the same reordering timer.

[0132] For example, the PDU set t-Reordering timer is defined as the reordering timer for a PDU set and is set by RRC signaling. This timer is set only for the DRB and is used to detect the loss of PDCP data PDUs belonging to the corresponding PDU set. All PDUs in the same PDU set share the same PDU set t-Reordering timer. At the receiving PDCP entity (e.g., in the terminal device 120), a new PDCP PDU set reordering timer (i.e., the t-Reordering timer) is started upon the first reception of a PDCP PDU belonging to a PDCP set from a lower layer. If the PDU set t-Reordering expires for a PDU set and at least one PDU / SDU of the PDCP set is lost, the receiving PDCP entity should discard all PDUs / SDUs belonging to this PDU set and / or all PDUs / SDUs of other PDU sets associated with this PDU set. For example, if PDU set N (the PDU set with set index "N") is lost, the receiving PDCP entity should also discard PDU sets with "Correlated PDU Set SN" field equal to N.

[0133] Specifically, in this case, the following processing flow may be executed based on the above description. TIFF2025532917000002.tif63168TIFF2025532917000003.tif44168

[0134] Additionally or alternatively, the following process flow may be performed. TIFF2025532917000004.tif39168TIFF2025532917000005.tif30168

[0135] Specifically, in some exemplary embodiments, if a request is received from an upper layer to pause transmission of a PDU set, and the reordering timer is running, the receiving PDCP entity in the terminal device 120 also stops and resets the reordering timer.

[0136] For example, if the upper layer requests the PDCP entity to pause (transmission of a PDU set), the receiving PDCP entity (e.g., in the terminal device 120)

[0137] - If t-Reordering or PDU set t-Reordering is running,

[0138] - Stop and reset t-Reordering or PDU set t-Reordering,

[0139] delivering all stored PDCP SDUs to the upper layer in ascending order of their associated COUNT values ​​after performing header decompression;

[0140] - Set RX_NEXT and RX_DELIV to their initial values.

[0141] In some other exemplary embodiments, if the value of the reordering timer is set by a higher layer, the receiving PDCP entity in terminal device 120 also stops and restarts the reordering timer while it is running.

[0142] For example, if the upper layer requests the PDCP entity to suspend, the receiving PDCP entity (e.g., in terminal device 120) may:

[0143] If the value of the PDU set t-Reordering is reset by an upper layer while the PDU set t-Reordering is being executed, the receiving PDCP entity in the terminal device 120:

[0144] - Update RX_REORD to RX_NEXT,

[0145] - PDU set t-Reordering should be stopped and restarted.

[0146] In some exemplary embodiments, when a discard timer expires for a PDCP SDU, the transmitting PDCP entity in terminal device 120 discards PDUs and / or SDUs belonging to the corresponding PDU set and / or PDUs and / or SDUs of other PDU sets associated with that PDU set.

[0147] For example, if the discardTimer expires for a PDCP SDU, the transmitting PDCP entity (e.g., in terminal device 120) should discard all PDUs / SDUs belonging to the corresponding PDU set and / or all PDUs / SDUs of other PDU sets associated with this PDU set. If the corresponding PDCP data PDU has already been submitted to the lower layer, the discard is indicated to the lower layer.

[0148] In some exemplary embodiments, in response to all PDUs in a PDU set being required by the application layer and at least one PDU and / or SDU of the PDCP set being configured as lost, the receiving PDCP entity (e.g., in terminal device 120) discards PDUs and / or SDUs belonging to the corresponding PDU set and / or PDUs / SDUs of other PDU sets associated with the PDU set when the reordering timer for the PDCP SDU expires.

[0149] For example, if RRC signaling configures all PDUs belonging to a PDU set to be required by the application layer and at least one PDU / SDU of the PDCP set is lost upon expiration of t-Reordering, the receiving PDCP entity (e.g., in terminal device 120) should discard all PDUs / SDUs belonging to this PDU set and / or all PDUs / SDUs of other PDU sets associated with this PDU set.

[0150] The following description introduces how to process the PDU set information during the handover procedure.

[0151] 4 shows an example signaling diagram of a communication process 400 according to some example embodiments of the present disclosure. For illustrative purposes only, the process 400 will be described with reference to FIG. 1. Specifically, the communication process 400 may be a handover process and may include a terminal device 120, a source network device 110-1, and a target network device 110-2.

[0152] In the communication process 600, which is a handover process, as described above, it is assumed that network device 110-1 is the source network device currently providing network services to terminal device 120, and network device 110-2 is the target network device that may provide network services to terminal device 120 from the time of handover, while source network device 110-1 will no longer provide network services to terminal device 120 from the time of handover. In other words, network services to terminal device 120 may be "handed over" from source network device 110-1 to target network device 110-2.

[0153] In some example embodiments, during handover execution, terminal device 120 further maintains a common PDU set SN assignment, where PDU set SN continuity is supported for both RLC-AM and Unacknowledgement (UM) DRBs with DAPS configured.

[0154] In some exemplary embodiments, the source network device 110-1 further sends a message for handover request to the target network device 110-2, passing information for preparing the handover to the target network device, the information including at least PDU set-related information, the PDU set-related information including at least information regarding the first parameter and the second parameter.

[0155] In some exemplary embodiments, the source network device 110-1 further maintains a PDU set serial number (SN) for the RLC-AM bearer and sends to the target network device the next PDU set SN to assign to a packet that does not have a PDU set SN.

[0156] In some example embodiments, the source network device 110-1 further transmits to the target network device 110-2 information regarding at least one of the first field, the second field, the third field, or the size of the PDU set.

[0157] In some example embodiments, the source network device 110-1 further transmits to the target network device 110-2 information regarding the importance level or priority or associated PDU set.

[0158] In some exemplary embodiments, if the DRB is configured with DAPS, the source network device 110-1 further sends a message for early state transfer to the target network device 110-2, where the values ​​of the PDU Set SN and / or Downlink Count carried in the message indicate the PDU Set SN, PDCP SN, and HFN of the first PDCP SDU that the source network device 110-1 will transfer to the target network device 110-2.

[0159] In some exemplary embodiments, the source network device 110-1 further assigns a SN and / or a PDU set SN to the downlink PDCP SDU until the source network device 110-1 sends a message for SN state transfer to the target network device 110-2.

[0160] In some exemplary embodiments, the message for SN state transfer indicates to target network device 110-2 the PDU set SN and count of the first missing PDCP SDU that target network device 110-2 should begin delivering.

[0161] In some exemplary embodiments, the source network device 110-1 further assigns a downlink PDCP SN and / or PDU set SN until the SN allocation is handed over to the target network device 110-2, schedules downlink data on the source radio link upon assignment of the downlink PDCP SN and / or PDU set SN by the source network device 110-1, begins forwarding downlink PDCP SDUs with the assigned PDCP SN and / or PDU set SN to the target network device 110-2, and maintains the PDU set SN, HFN, and PDCP SN after the SN allocation is handed over to the target network device 110-2.

[0162] In some example embodiments, the source network device 110-1 further transmits to the target network device 110-2 information regarding at least one of the first field, the second field, the third field, or the size of the PDU set.

[0163] In some example embodiments, the source network device 110-1 further transmits to the target network device 110-2 information regarding the importance level or priority or associated PDU set.

[0164] In some exemplary embodiments, the source network device 110-1 further sends a message for a handover request to the target network device 110-2, the message including PDU set-related information including information about at least a first parameter and a second parameter, and sends a message for an SN state transfer to the target network device 110-2.

[0165] In some exemplary embodiments, the source network device 110-1 further requests DAPS handover for one or more DRBs and sends a message for early state transfer to the target network device 110-2 for the DRBs for which DAPS is configured, the message including values ​​of PDU Set SN and / or Downlink Count indicating the PDU Set SN, PDCP SN, and HFN of the first PDCP SDU that the source network device 110-1 will transfer to the target network device 110-2.

[0166] In some exemplary embodiments, for a DRB that does not have DAPS configured, the source network device 110-1 further sends a message for SN state transfer to the target network device 110-2.

[0167] In some exemplary embodiments, the target network device 110-2 further receives a message for handover request from the source network device 110-1, passing information for preparing the handover at the target network device 110-2, the information including at least PDU set-related information, the PDU set-related information including at least information regarding a first parameter and a second parameter.

[0168] In some exemplary embodiments, upon determining that a DAPS handover is configured for a Radio Link Control-Acknowledgement (RLC-UM) bearer, the target network device 110-2 further resets the PDU set SN, PDCP SN, and HFN for the RLC-UM bearer.

[0169] As shown in FIG. 4, in step 3, the source gNB (i.e., the source network device 110-1) issues a handover request message to the target gNB (i.e., the target network device 110-2) passing a transparent RRC container containing information necessary for preparing a handover on the target side. The information includes at least the target cell ID, KgNB*, the C-RNTI of the terminal device 120 at the source network device 110-1, RRM configuration including the inactive time of the terminal device 120, basic AS configuration including antenna info and DL carrier frequency, the current QoS flow-to-DRB mapping rule applied to the terminal device 120, SIB1 from the source network device 110-1, the capabilities of the terminal device 120 for different RATs, PDU session-related information, PDU set-related information (optional, this information may be in the QoS profile), and, if possible, measurement information reported by the UE including beam-related information. The PDU session-related information includes slice information and a QoS flow-level QoS profile. The PDU set related information includes whether all PDUs are required for the PDU set, whether / how to drop PDUs, etc. The source gNB may also request a DAPS handover for one or more DRBs.

[0170] Also, as shown in Figure 4, in step 7a, for a DRB for which DAPS is configured, the source gNB (i.e., source network device 110-1) sends an EARLY STATUS TRANSFER message. The PDU Set SN / DL COUNT value conveyed in the EARLY STATUS TRANSFER message indicates the PDU Set SN, PDCP SN, and HFN of the first PDCP SDU that the source gNB (i.e., source network device 110-1) will transfer to the target gNB (i.e., target network device 110-2). The source gNB does not stop allocating SN / PDU Set SN to downlink PDCP SDUs until it sends an SN STATUS TRANSFER message to the target gNB in ​​step 8b.

[0171] In step 7, for DRBs where DAPS is not configured, the source gNB sends an SN STATUS TRANSFER message to the target gNB to convey the uplink PDCP SN receiver state and downlink PDCP SN transmitter state of the DRB for which PDCP state preservation applies (i.e., for RLC-AM). The uplink PDCP SN receiver state includes the PDCP SN of at least the first missing UL PDCP SDU and may include a bitmap (if any) of the reception state of out-of-order UL PDCP SDUs that the terminal device 120 needs to retransmit in the target cell (associated with the target gNB). The downlink PDCP SN transmitter state indicates the next PDCP SN that the target gNB should allocate to new PDCP SDUs that do not yet have a PDCP SN.

[0172] In the U-plane process for handover, for RLC-AM bearers, in-order delivery, and application duplication, the PDCP SN is maintained on a per-DRB basis, and the source gNB informs the target gNB of the next DL PDCP SN to allocate to packets (from the source gNB or from the UPF) that do not yet have a PDCP sequence number. For security synchronization, the HFN is also maintained, and the source gNB provides the target gNB with one reference HFN for the UL and one reference HFN for the DL, i.e., the HFN and the corresponding SN. The source gNB informs the target gNB of at least one of the following: "PDU Set SN," "Start indication," "End indication," or the size of the PDU set. Specifically, the PDCP Set SN is maintained, and the source gNB informs the target gNB of the next PDU Set SN to allocate to packets (from the source gNB or from the UPF) that do not yet have a PDU Set SN. The source gNB may also inform the target gNB about the "start indication" / "stop indication" and / or the size of the PDU set. If necessary, the importance level (or priority, or PDU set type) or the "correlated PDU set SN" should also be informed from the source gNB to the target gNB. Furthermore, for RLC-UM bearers, the PDU set SN, PDCP SN and HFN are reset in the target gNB unless a DAPS handover is configured for the bearer.

[0173] In some exemplary embodiments, in the case of a DAPS handover, both downlink and uplink operations are performed at a PDU set granularity.

[0174] In one example, for downlink processing, the source gNB is responsible for allocating downlink PDCP SN / PDU sets SN until the SN allocation is handed over to the target gNB 110-2 and data transfer occurs. That is, the source gNB does not stop allocating PDCP SN / PDU sets SN to downlink packets until it receives a HANDOVER SUCCESS message and sends an SN STATUS TRANSFER message to the target gNB. Upon allocation of a downlink PDCP SN / PDU set SN by the source gNB, it begins scheduling downlink data on the source radio link and begins transferring downlink PDCP SDUs with the allocated PDCP SN / PDU set SN to the target gNB. For security synchronization, the HFN is maintained for transferred downlink SDUs with the PDCP SN allocated by the source gNB. The source gNB sends an EARLY STATUS TRANSFER message conveying a DL COUNT value indicating the PDCP SN and HFN of the first PDCP SDU that the source gNB will transfer to the target gNB. After the SN allocation is handed over to the target gNB, the PDU Set SN, HFN, and PDCP SN are maintained. The SN STATUS TRANSFER message indicates, for RLC-UM as well, the next DL PDCP SN / PDU Set SN to assign to packets that do not yet have a PDCP sequence number / PDU Set SN. The "start indication" / "end indication" and / or the size of the PDU set may also be handed over to the target gNB. If necessary, the importance level (or priority, or PDU Set type) or the "correlated PDU Set SN" should be signaled from the source gNB to the target gNB.

[0175] In another example, for uplink processing, during handover execution, the UE maintains separate security contexts and ROHC header compressor contexts for uplink transmissions to the source and target gNBs. The UE maintains a common UL PDCP SN / PDU Set SN assignment. PDCP SN / PDU Set SN continuity is supported for both RLC-AM and UM DRBs with DAPS configured. The PDU Set SN, HFN, and PDCP SN are maintained in the target gNB. For RLC-UM, the SN STATUS TRANSFER message also indicates the PDU Set SN and COUNT of the first missing PDCP SDU that the target should start delivering to the 5GC.

[0176] In this way, packet processing at PDU set granularity is supported, and PDU set-based processing is also supported. Therefore, processing of XR / media services can be performed at PDU set granularity rather than PDU granularity. At the same time, processing of each data packet in a QoS flow is no longer relatively independent. However, PDU sets that depend on other PDU sets can be processed (e.g., dropped / discarded) based on the other PDU sets. As a result, communication quality and network performance are improved.

[0177] 5 is a flowchart of an example method 500 implemented in a terminal device, according to some embodiments of the present disclosure. For illustrative purposes, the method 500 will be described from the perspective of the terminal device 120 and with reference to FIG.

[0178] In block 510, the terminal device 120 receives from the network device 120 at least one of parameters associated with the PDU set: a first parameter indicating whether all PDUs in the PDU set are required by the application layer, a second parameter indicating whether the PDU set will be discarded if additional PDU sets associated with the PDU set are lost or discarded, a third parameter indicating a discard timer for the PDU set, or a fourth parameter indicating a reordering timer for the PDU set. In block 520, the terminal device 120 processes the PDU set based on the received at least one of the parameters.

[0179] In some exemplary embodiments, the header of a PDCP data PDU defines at least one of the following fields: a first field indicating the SN of the PDU set to which the PDCP data PDU belongs; a second field indicating whether the PDCP data PDU is the first PDU of the PDU set to which it belongs; or a third field indicating whether the PDCP data PDU is the last PDU of the PDU set to which it belongs.

[0180] In some exemplary embodiments, the header of the PDCP data PDU further defines at least one of the following fields: a fourth field indicating the SN of another PDU set, where the PDU set to which the PDCP data PDU belongs is associated with the PDU set identified by the fourth field; a fifth field indicating whether the fourth field is present in the header of the PDCP data PDU; or a sixth field indicating the importance or priority of the PDU set.

[0181] In some exemplary embodiments, the terminal device further determines a range of counts or PDCP SNs belonging to the PDU set from a first count or first PDCP SN, which is a count or PDCP SN of PDCP data PDUs with the second field set to 1, to a second count or second PDCP SN, which is a count or PDCP SN of PDCP data PDUs with the third field set to 1, and determines whether the PDCP set has lost at least one PDU based on information about the PDU set SN, the count or PDCP SN, the second field, and the third field.

[0182] In some exemplary embodiments, the second field and the third field each use one bit in the PDCP header.

[0183] In some exemplary embodiments, the fifth field occupies one bit in the PDCP header, and in response to the fifth field indicating that the fourth field is present in the PDCP header, the fourth field is newly added to the PDCP header.

[0184] In some exemplary embodiments, the sixth field uses at least one bit in the PDCP header.

[0185] In some example embodiments, packets from higher layers are organized in PDU sets at the PDCP layer, and PDU set information is transmitted in-band in the PDCP header of each PDU in the PDU set.

[0186] In some exemplary embodiments, the terminal device 120 further performs maintaining a common PDU set SN allocation at the terminal device 120 during handover execution, and PDU set SN continuity is supported for both RLC-AM and UM DRB with DAPS configured.

[0187] In some exemplary embodiments, the terminal device 120 further performs the following: upon first receiving a PDCP SDU belonging to a PDU set from a higher layer, starting a discard timer associated with the PDU set; and, if the discard timer for the SDU set expires, discarding PDUs and / or SDUs belonging to the corresponding PDU set and / or PDUs and / or SDUs of other PDU sets associated with the PDU set, wherein PDUs within the same PDU set share the same discard timer.

[0188] In some exemplary embodiments, the terminal device 120 further performs the following: upon first receiving a PDU belonging to a PDU set from a lower layer, starting a reordering timer associated with the PDU set; and, if the reordering timer for the SDU set expires, discarding PDUs and / or SDUs belonging to the corresponding PDU set and / or PDUs and / or SDUs of other PDU sets associated with the PDU set, wherein PDUs within the same PDU set share the same reordering timer.

[0189] In some exemplary embodiments, the terminal device 120 further performs the following: stopping and resetting the reordering timer when the reordering timer is running if requested by an upper layer to pause transmission of the PDU set.

[0190] In some exemplary embodiments, terminal device 120 further stops and restarts the reordering timer while the reordering timer is running if the reordering timer value is set by a higher layer.

[0191] In some exemplary embodiments, the terminal device 120 further performs the following: if a discard timer expires for a PDCP SDU, discarding PDUs and / or SDUs belonging to the corresponding PDU set and / or PDUs and / or SDUs of other PDU sets associated with the PDU set.

[0192] In some exemplary embodiments, the terminal device 120 further performs the following: if a reordering timer expires for a PDCP SDU, in response to all PDUs in the PDU set being required by the application layer and at least one PDU and / or SDU of the PDCP set being configured as lost, discarding PDUs and / or SDUs belonging to the corresponding PDU set and / or PDUs / SDUs of other PDU sets associated with the PDU set.

[0193] In this way, packet processing at PDU set granularity is supported, and PDU set-based processing is also supported. Therefore, processing of XR / media services can be performed at PDU set granularity rather than PDU granularity. At the same time, processing of each data packet in a QoS flow is no longer relatively independent. However, PDU sets that depend on other PDU sets can be processed (e.g., dropped / discarded) based on the other PDU sets. As a result, communication quality and network performance are improved.

[0194] 6 is a flowchart of an example method 600 implemented in a network device according to some embodiments of the present disclosure. For purposes of discussion, the method 600 will be described from the perspective of the network device 110 and with reference to FIGS. 1 and 5.

[0195] In block 610, the network device 110 determines at least one of the following parameters associated with the PDU set: a first parameter indicating whether all PDUs in the PDU set are needed by the application layer, a second parameter indicating whether the PDU set will be discarded if additional PDU sets associated with the PDU set are lost or discarded, a third parameter indicating a discard timer for the PDU set, or a fourth parameter indicating a reordering timer for the PDU set. In block 620, the network device 110 transmits at least one of the parameters to the terminal device 120.

[0196] In some exemplary embodiments, the header of a PDCP data PDU defines at least one of the following fields: a first field indicating the SN of the PDU set to which the PDCP data PDU belongs; a second field indicating whether the PDCP data PDU is the first PDU of the PDU set to which it belongs; or a third field indicating whether the PDCP data PDU is the last PDU of the PDU set to which it belongs.

[0197] In some exemplary embodiments, the header of the PDCP data PDU further defines at least one of the following fields: a fourth field indicating the SN of another PDU set, where the PDU set to which the PDCP data PDU belongs is associated with the PDU set identified by this field; a fifth field indicating whether the fourth field is present in the header of the PDCP data PDU; or a sixth field indicating the importance or priority of the PDU set.

[0198] In some exemplary embodiments, the network device is the source network device 110-1 from which the terminal device 120 is handed over to the target network device 110-2.

[0199] In some example embodiments, the source network device 110-1 sends a message for handover request to the target network device 110-2, passing information for preparing the handover to the target network device, the information including at least PDU set-related information, the PDU set-related information including at least information regarding a first parameter and a second parameter.

[0200] In some exemplary embodiments, the source network device 110-1 further performs the following: maintaining a PDU set SN for the RLC-AM bearer; and transmitting to the target network device 110-2 the next PDU set SN to be assigned to a packet that does not have a PDU set SN.

[0201] In some exemplary embodiments, the source network device 110-1 further transmits to the target network device 110-2 information regarding at least one of the first field, the second field, the third field, or the size of the PDU set.

[0202] In some example embodiments, the source network device 110-1 further transmits information regarding the importance level or priority or associated PDU set to the target network device 110-2.

[0203] In some exemplary embodiments, the source network device 110-1 further performs, if DAPS is configured in the DRB, sending a message for early state transfer to the target network device 110-2, where the values ​​of the PDU Set SN and / or Downlink Count carried in the message indicate the PDU Set SN, PDCP SN, and HFN of the first PDCP SDU that the source network device 110-1 will transfer to the target network device 110-2.

[0204] In some exemplary embodiments, the source network device 110-1 further performs assigning SNs and / or PDU set SNs to downlink PDCP SDUs before sending a message for SN state transfer to the target network device 110-2.

[0205] In some exemplary embodiments, the message for SN state transfer indicates to target network device 110-2 the PDU set SN and count of the first missing PDCP SDU that target network device 110-2 should start delivering.

[0206] In some example embodiments, the source network device 110-1 further assigns a downlink PDCP SN and / or PDU set SN until the SN allocation is handed over to the target network device 110-2; upon assignment of the downlink PDCP SN and / or PDU set SN by the source network device 110-1, begins scheduling downlink data on the source radio link and forwarding downlink PDCP SDUs with the assigned PDCP SN and / or PDU set SN to the target network device 110-2; and maintains the PDU set SN, HFN, and PDCP SN after the SN allocation is handed over to the target network device 110-2.

[0207] In some exemplary embodiments, the source network device 110-1 further transmits to the target network device 110-2 information regarding at least one of the first field, the second field, the third field, or the size of the PDU set.

[0208] In some example embodiments, the source network device 110-1 further transmits information regarding the importance level or priority or associated PDU set to the target network device 110-2.

[0209] In some exemplary embodiments, the source network device 110-1 further performs the following: sending a message for a handover request to the target network device 110-2, the message including PDU set-related information including information about at least a first parameter and a second parameter; and sending a message for SN state transfer to the target network device.

[0210] In some exemplary embodiments, the source network device 110-1 further performs: requesting a DAPS handover for one or more DRBs; and for the DRBs for which DAPS is configured, sending a message for early state transfer to the target network device 110-2, where the message includes values ​​of a PDU Set SN and / or a Downlink Count indicating the PDU Set SN, PDCP SN, and HFN of the first PDCP SDU that the source network device 110-1 will transfer to the target network device 110-2.

[0211] In some exemplary embodiments, the source network device 110-1 further performs sending a message for SN state transfer to the target network device 110-2 for a DRB for which DAPS is not configured.

[0212] In some exemplary embodiments, the network device is a target network device 110-2 to which terminal device 120 is being handed over from source network device 110-1.

[0213] In some exemplary embodiments, the target network device 110-2 further receives from the source network device 110-1 a message for a handover request, the message passing information for preparing the handover at the target network device, the information including at least PDU set-related information, the PDU set-related information including at least information regarding a first parameter and a second parameter.

[0214] In some exemplary embodiments, if the target network device 110-2 determines that a DAPS handover is configured for the RLC-UM bearer, it further resets the PDU set SN, PDCP SN, and HFN for the RLC-UM bearer.

[0215] In this way, packet processing at PDU set granularity is supported, and PDU set-based processing is also supported. Therefore, processing of XR / media services can be performed at PDU set granularity rather than PDU granularity. At the same time, processing of each data packet in a QoS flow is no longer relatively independent. However, PDU sets that depend on other PDU sets can be processed (e.g., dropped / discarded) based on the other PDU sets. As a result, communication quality and network performance are improved.

[0216] 7 is a schematic block diagram of an apparatus 700 suitable for implementing embodiments of the present disclosure. Apparatus 700 may be viewed as another exemplary implementation of terminal device 120 and / or network device 110 as shown in FIG. 1. Thus, apparatus 700 may be implemented in, or as at least a part of, terminal device 120 or network device 110.

[0217] As shown, the apparatus 700 comprises a processor 710, a memory 720 coupled to the processor 710, a suitable transmitter (TX) and receiver (RX) 740 coupled to the processor 710, and a communication interface coupled to the TX / RX 740. The memory 710 stores at least a portion of a program 730. The TX / RX 740 is used for bidirectional communication. The TX / RX 740 has at least one antenna to facilitate communication, although the access nodes referred to in this disclosure may actually have multiple antennas. The communication interface may represent any interface required for communication with other network elements, such as an X2 interface for bidirectional communication between eNBs, an S1 interface for communication between a Mobility Management Entity (MME) / Serving Gateway (S-GW) and an eNB, a Un interface for communication between an eNB and a Relay Node (RN), or a Uu interface for communication between an eNB and a terminal device.

[0218] The program 730 is assumed to include program instructions that, when executed by the associated processor 710, enable the device 700 to operate in accordance with embodiments of the present disclosure, as described herein with reference to Figures 2-6. The embodiments herein may be implemented by computer software executable by the processor 710 of the device 700, by hardware, or by a combination of software and hardware. The processor 710 may be configured to implement various embodiments of the present disclosure. Furthermore, the combination of the processor 710 and the memory 720 may form a processing means 750 suitable for implementing various embodiments of the present disclosure.

[0219] Memory 720 may be of any type suitable for a local technology network and may be implemented using any suitable data storage technology, including, by way of non-limiting example, non-transitory computer-readable storage media, semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and removable memory. While only one memory 720 is shown in device 700, there may be several physically distinct memory modules within device 700. Processor 710 may be of any type suitable for a local technology network and may include, by way of non-limiting example, 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 architecture. Device 700 may have multiple processors, for example, application-specific integrated circuit chips time-slaved to a clock that synchronizes the main processor.

[0220] In summary, the embodiments of the present disclosure can provide the following solutions:

[0221] The present disclosure provides a method of communication, the method including: receiving, in a terminal device, from a network device, at least one of parameters associated with a protocol data unit (PDU) set: a first parameter indicating whether all PDUs in the PDU set are required by an application layer; a second parameter indicating whether the PDU set is discarded if an additional PDU set associated with the PDU set is lost or discarded; a third parameter indicating a discard timer for the PDU set; or a fourth parameter indicating a reordering timer for the PDU set; and processing the PDU set based on the received at least one of the parameters.

[0222] In one embodiment, in the method, the header of a Packet Data Convergence Protocol (PDCP) data PDU is defined with at least one of the following fields: a first field indicating the serial number (SN) of the PDU set to which the PDCP data PDU belongs; a second field indicating whether the PDCP data PDU is the first PDU of the PDU set to which it belongs; or a third field indicating whether the PDCP data PDU is the last PDU of the PDU set to which it belongs.

[0223] In one embodiment, in the method, the header of the PDCP data PDU further defines at least one of the following fields: a fourth field indicating the SN of another PDU set, wherein the PDU set to which the PDCP data PDU belongs is associated with the PDU set identified by the fourth field; a fifth field indicating whether the fourth field is present in the header of the PDCP data PDU; or a sixth field indicating the importance or priority of the PDU set.

[0224] In one embodiment, the method further comprises determining a range of counts or PDCP SNs belonging to a PDU set, from a first count or first PDCP SN, which is a count or PDCP SN of PDCP data PDUs with the second field set to 1, to a second count or second PDCP SN, which is a count or PDCP SN of PDCP data PDUs with the third field set to 1, and determining whether a PDCP set has lost at least one PDU based on information about the PDU set SN, the count or PDCP SN, the second field, and the third field.

[0225] In one embodiment, in the method, the second field and the third field each occupy one bit in the PDCP header.

[0226] In one embodiment, in the method, the fifth field occupies one bit in the PDCP header, and the fourth field is newly added to the PDCP header in response to the fifth field indicating that the fourth field is present in the PDCP header.

[0227] In one embodiment, in the method, the sixth field uses at least one bit in the PDCP header.

[0228] In one embodiment, in the method, packets from higher layers are organized in units of PDU sets at the PDCP layer, and PDU set information is transmitted in-band in the PDCP header of each PDU in a PDU set.

[0229] In one embodiment, the method further includes maintaining a common PDU set SN allocation in the terminal device during handover execution, and PDU set SN continuity is supported for both RLC-AM and UM DRB with DAPS configured.

[0230] In one embodiment, the method further comprises, upon first reception of a PDCP SDU belonging to a PDU set from a higher layer, starting a discard timer associated with the PDU set, and, if the discard timer for the SDU set expires, discarding PDUs and / or SDUs belonging to the corresponding PDU set and / or PDUs and / or SDUs of other PDU sets associated with the PDU set, wherein PDUs within the same PDU set share the same discard timer.

[0231] In one embodiment, the method further comprises starting a reordering timer associated with a PDU set upon first reception of a PDU belonging to the PDU set from a lower layer, and discarding PDUs and / or SDUs belonging to the corresponding PDU set and / or PDUs and / or SDUs of other PDU sets associated with the PDU set if the reordering timer for the SDU set expires, wherein PDUs within the same PDU set share the same reordering timer.

[0232] In one embodiment, the method further comprises stopping and resetting the reordering timer when the reordering timer is running if requested by an upper layer to pause transmission of the PDU set.

[0233] In one embodiment, the method further includes stopping and restarting the reordering timer while the timer is running if the value of the reordering timer is set by a higher layer.

[0234] In one embodiment, the method further includes, if a discard timer expires for a PDCP SDU, discarding PDUs and / or SDUs belonging to the corresponding PDU set and / or PDUs and / or SDUs of other PDU sets associated with the PDU set.

[0235] In one embodiment, the method further comprises, in response to all PDUs in a PDU set being required by the application layer and at least one PDU and / or SDU of a PDCP set being set as lost, discarding PDUs and / or SDUs belonging to the corresponding PDU set and / or PDUs / SDUs of other PDU sets associated with the PDU set if a reordering timer for the PDCP SDU expires.

[0236] The present disclosure provides a method of communication, the method including: determining, in a network device, at least one of parameters associated with a protocol data unit (PDU) set, the parameters being a first parameter indicating whether all PDUs in the PDU set are required by an application layer; a second parameter indicating whether the PDU set will be discarded if an additional PDU set associated with the PDU set is lost or discarded; a third parameter indicating a discard timer for the PDU set; or a fourth parameter indicating a reordering timer for the PDU set; and transmitting the at least one of the parameters to a terminal device.

[0237] In one embodiment, in the method, the header of a PDCP data PDU defines at least one of a first field indicating the serial number (SN) of the PDU set to which the PDCP data PDU belongs, a second field indicating whether the PDCP data PDU is the first PDU of the PDU set to which it belongs, or a third field indicating whether the PDCP data PDU is the last PDU of the PDU set to which it belongs.

[0238] In one embodiment, the method further defines at least one of the following fields in the header of the PDCP data PDU: a fourth field indicating the SN of another PDU set, where the PDU set to which the PDCP data PDU belongs is associated with the PDU set identified by this field; a fifth field indicating whether the fourth field is present in the header of the PDCP data PDU; or a sixth field indicating the importance or priority of the PDU set.

[0239] In one embodiment, in the method, the network device is a source network device from which the terminal device is handed over to a target network device.

[0240] In one embodiment, the method further includes sending a message for a handover request to the target network device, passing information for preparing a handover to the target network device, the information including at least PDU set related information, and the PDU set related information including at least information regarding the first parameter and the second parameter.

[0241] In one embodiment, the method further includes maintaining a PDU set serial number (SN) for the RLC-AM bearer and sending to the target network device a next PDU set SN to assign to a packet that does not have a PDU set SN.

[0242] In one embodiment, the method further includes transmitting information regarding at least one of the first field, the second field, the third field, or the size of the PDU set to the target network device.

[0243] In one embodiment, the method further comprises sending information about an importance level or priority or an associated PDU set to the target network device.

[0244] In one embodiment, the method further includes, if DAPS is configured in the DRB, sending a message for early state transfer to the target network device, wherein the values ​​of the PDU set SN and / or downlink count conveyed in the message indicate the PDU set SN, PDCP SN and HFN of the first PDCP SDU that the source network device will transfer to the target network device.

[0245] In one embodiment, the method further includes allocating SNs and / or PDU sets SNs to downlink PDCP SDUs until sending a message for SN state transfer to the target network device.

[0246] In one embodiment, in the method, the message for SN state transfer indicates to the target network device a PDU set SN and count of the first missing PDCP SDU that the target network device should start delivering.

[0247] In one embodiment, the method further includes assigning a downlink PDCP SN and / or PDU Set SN until SN allocation is handed over to the target network device; upon assignment of the downlink PDCP SN and / or PDU Set SN by the source network device, starting to schedule downlink data on the source radio link and forward downlink PDCP SDUs with the assigned PDCP SN and / or PDU Set SN to the target network device; and maintaining the PDU Set SN, HFN, and PDCP SN after SN allocation is handed over to the target network device.

[0248] In one embodiment, the method further includes transmitting information regarding at least one of the first field, the second field, the third field, or the size of the PDU set to the target network device.

[0249] In one embodiment, the method further comprises sending information about an importance level or priority or an associated PDU set to the target network device.

[0250] In one embodiment, the method further includes sending a message for a handover request to the target network device, the message including Protocol Data Unit (PDU) set related information including information about at least the first parameter and the second parameter, and sending a message for SN state transfer to the target network device.

[0251] In one embodiment, the method further includes requesting a DAPS handover for one or more DRBs, and for a DRB configured with DAPS, sending a message for early state transfer to the target network device, wherein the message includes a PDU Set SN and / or a Downlink Count value indicating a PDU Set SN, a PDCP SN, and an HFN of a first PDCP SDU to be transferred from the source network device to the target network device.

[0252] In one embodiment, the method further includes, for a DRB for which DAPS is not configured, sending a message for SN state transfer to the target network device.

[0253] In one embodiment, in the method, the network device is a target network device to which the terminal device is handed over from the source network device.

[0254] In one embodiment, the method further includes receiving a message for a handover request from the source network device, passing information for preparing the handover in the target network device, the information including at least PDU set related information, and the PDU set related information including at least information regarding the first parameter and the second parameter.

[0255] In one embodiment, the method further includes resetting a PDU Set SN, a PDCP SN, and an HFN for the RLC-UM bearer upon determining that the RLC-UM bearer is configured for DAPS handover.

[0256] The present disclosure provides a terminal device comprising a processor and a memory storing computer program code, the memory and the computer program code, together with the processor, configured to cause the terminal device to execute the above method implemented in the terminal device 120.

[0257] The present disclosure provides a network device comprising a processor and a memory storing computer program code, the memory and the computer program code, together with the processor, configured to cause the network device to perform the above method implemented in the network device 110.

[0258] The present disclosure provides a computer-readable medium that stores instructions that, when executed by a processor of a device, cause the device to perform the above-described method implemented in the terminal device 120 or the network device 110.

[0259] Overall, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic, or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software executable by a controller, microprocessor, or other computing device. While various aspects of embodiments of the present disclosure have been illustrated and described using block diagrams, flowcharts, or other pictorial representations, it should be understood that the blocks, devices, systems, techniques, or methods described herein may be implemented, by way of non-limiting example, in hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing device, or any combination thereof.

[0260] The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer-readable storage medium. The computer program product includes computer-executable instructions, such as instructions included in program modules, that execute within a device on a target real or virtual processor to perform the processes or methods described above with reference to FIGS. 5-6. Generally, 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 between program modules as desired. The machine-executable instructions of the program modules may be executed within local or distributed devices. In a distributed device, program modules may be located in both local and remote storage media.

[0261] 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 device, and when executed by the processor or controller, cause the program code to implement the functions / acts specified in the flowcharts and / or block diagrams. 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.

[0262] The above-described program code may be embodied on a machine-readable medium, which may be any tangible medium that can contain or store a program used by or associated with an instruction execution system, apparatus, or device. The machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. The machine-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 aforementioned media. More specific examples of a machine-readable storage medium may include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0263] Although operations have been described in a particular order, it should not be understood that performing such operations in the particular order or sequence shown, or performing all of the operations described, is required to achieve desirable results. In some cases, multitasking and parallel processing may be advantageous. Similarly, while several specific implementation details are included in the above discussion, 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.

[0264] Although the present disclosure has been described in language specific to structural features and / or methodological acts, it should be understood that the present disclosure, as defined in the appended claims, is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. A method of communication comprising: In the terminal device, a parameter associated with a protocol data unit (PDU) set is received from the network device: a first parameter indicating whether all PDUs in the set of PDUs are required by an application layer; a second parameter indicating whether the set of PDUs is discarded if an additional set of PDUs associated with the set of PDUs is lost or discarded; a third parameter indicating a discard timer for the set of PDUs; a fourth parameter indicating a reordering timer for the set of PDUs; receiving at least one of: processing the set of PDUs based on the received at least one of the parameters; A method comprising:

2. The Packet Data Convergence Protocol (PDCP) data PDU header contains: a first field indicating a serial number (SN) of a PDU set to which the PDCP data PDU belongs; a second field indicating whether the PDCP Data PDU is the first PDU of the PDU set to which it belongs; or a third field indicating whether the PDCP data PDU is the last PDU of the PDU set to which it belongs; At least one field of The second field and the third field each use one bit in the PDCP header. The method of claim 1.

3. The header of the PDCP data PDU includes: a fourth field indicating the SN of another PDU set, where the PDU set to which the PDCP data PDU belongs is associated with the PDU set identified by said field; a fifth field indicating whether the fourth field is present in a header of the PDCP data PDU; or a sixth field indicating the importance or priority of the PDU set; At least one of the following is further defined: the fourth field is newly added to the PDCP header in response to the fifth field indicating that the fourth field is present in the PDCP header; The sixth field uses at least one bit in the PDCP header. The method of claim 2.

4. determining a range of counts or PDCP SNs belonging to the PDU set from a first count or first PDCP SN, which is a count or PDCP SN of PDCP Data PDUs with the second field set to 1, to a second count or second PDCP SN, which is a count or PDCP SN of PDCP Data PDUs with the third field set to 1; determining whether a PDCP set has lost at least one PDU based on information about the PDU set SN, the count or PDCP SN, the second field, and the third field; The method of claim 2 further comprising:

5. maintaining a common PDU set SN allocation in the terminal device during handover execution; The PDU Set SN continuity is supported for both Radio Link Control - Acknowledgement (RLC-AM) and Unacknowledgement (UM) Data Radio Bearers (DRBs) with Dual Active Protocol Stack (DAPS) configured. The method of claim 2.

6. Upon first reception of a Packet Data Convergence Protocol (PDCP) Service Data Unit (SDU) belonging to a set of PDUs from an upper layer, starting a discard timer associated with the set of PDUs; If the discard timer for the SDU set expires, discarding PDUs and / or SDUs belonging to the corresponding PDU set and / or PDUs and / or SDUs of other PDU sets associated with the PDU set; PDUs within the same PDU set share the same discard timer The method of claim 1.

7. - starting a reordering timer associated with a set of PDUs upon first reception of the PDUs from a lower layer; If the reordering timer for the SDU set expires, discarding PDUs and / or SDUs belonging to the corresponding PDU set and / or PDUs and / or SDUs of other PDU sets associated with the PDU set; PDUs in the same PDU set share the same reordering timer The method of claim 1.

8. discarding PDUs and / or SDUs belonging to a corresponding Packet Data Convergence Protocol (PDCP) Service Data Unit (SDU) set and / or PDUs and / or SDUs of other PDU sets associated with said PDU set, if a discard timer for said PDCP Service Data Unit expires; The method of claim 1 further comprising:

9. discarding PDUs and / or SDUs belonging to a Packet Data Convergence Protocol (PDCP) set and / or PDUs / SDUs of other PDU sets associated with the PDCP set if a reordering timer for the PDCP SDU expires, in response to all PDUs in the PDU set being required by the application layer and at least one PDU and / or SDU of the PDCP set being configured as lost; The method of claim 1 further comprising:

10. A method of communication comprising: In a network device, a parameter associated with a Protocol Data Unit (PDU) set is a first parameter indicating whether all PDUs in the set of PDUs are required by an application layer; a second parameter indicating whether the set of PDUs is discarded if an additional set of PDUs associated with the set of PDUs is lost or discarded; a third parameter indicating a discard timer for the set of PDUs; a fourth parameter indicating a reordering timer for the set of PDUs; determining at least one of: transmitting said at least one of said parameters to a terminal device; A method comprising:

11. The PDCP data PDU header includes: a first field indicating a serial number (SN) of a PDU set to which the PDCP data PDU belongs; a second field indicating whether the PDCP Data PDU is the first PDU of the PDU set to which it belongs; or a third field indicating whether the PDCP Data PDU is the last PDU of the PDU set to which it belongs; At least one field of The method of claim 10.

12. The network device is a source network device from which the terminal device is handed over to a target network device. The method of claim 10.

13. sending a message for a handover request from the source network device to the target network device, the message passing information for preparing a handover to the target network device; the information includes at least PDU set related information; The PDU set related information includes information on at least the first parameter and the second parameter. The method of claim 12.

14. Maintaining a PDU set Serial Number (SN) for a Radio Link Control - Acknowledgement (RLC-AM) bearer; sending to the target network device a next PDU set SN to be assigned to packets that do not have a PDU set SN; The method of claim 13 further comprising:

15. the target network device, information regarding at least one of the first field, the second field, the third field, or the size of the PDU set; or Information about the importance level or priority or associated PDU set; transmitting at least one of: Also includes The method of claim 13.

16. If a Dual Active Protocol Stack (DAPS) is configured in the DRB, sending a message for early state transfer to the target network device; The PDU Set SN and / or Downlink Count values ​​carried in the message indicate the PDU Set SN, PDCP SN, and Hyper Frame Number (HFN) of the first PDCP SDU that the source network device will transmit to the target network device. The method of claim 13.

17. Allocating SNs and / or PDU set SNs to downlink PDCP SDUs until sending a message for SN state transfer to the target network device; 17. The method of claim 16 further comprising:

18. The message for SN state transfer indicates to the target network device the PDU set SN and count of the first missing PDCP SDU that the target network device should start delivering.

17. The method of claim 16.

19. assigning downlink PDCP SNs and / or PDU set SNs until SN allocation is handed over to the target network device; Upon assignment of downlink PDCP SNs and / or PDU Set SNs by the source network device, scheduling downlink data on the source radio link and starting to transfer downlink PDCP SDUs with allocated PDCP SNs and / or PDU Set SNs to the target network device; Maintaining a PDU set SN, HFN, and PDCP SN after the SN allocation is handed over to the target network device; 17. The method of claim 16 further comprising:

20. sending a message for handover request to the target network device, the message including a Protocol Data Unit (PDU) set related information including information about at least the first parameter and the second parameter; sending a message for SN state transfer to the target network device; 20. The method of claim 19 further comprising:

21. Requesting a Dual Active Protocol Stack (DAPS) handover for one or more Data Radio Bearers (DRBs); For a DRB with DAPS configured, sending a message for early state transfer to the target network device; The message includes a PDU Set SN and / or a Downlink Count value indicating a PDU Set SN, a PDCP SN, and an HFN of a first PDCP SDU that the source network device will forward to the target network device.

21. The method of claim 20.

22. receiving, at the target network device, from the source network device, a message for a handover request, the message passing information for preparing the handover at the target network device; the information includes at least PDU set related information; The PDU set related information includes information on at least the first parameter and the second parameter. The method of claim 12.

23. A terminal device comprising a processor and a memory storing computer program code, The memory and the computer program code together with the processor are configured to cause the terminal device to carry out the method according to any one of claims 1 to 9. Terminal device.

24. 1. A network device comprising a processor and a memory storing computer program code, The memory and the computer program code together with the processor are configured to cause the network device to perform the method of any one of claims 10 to 22. Network equipment.

25. storing instructions which, when executed by a processor of a device, cause said device to carry out a method according to any one of claims 1 to 9 or any one of claims 10 to 22; Computer-readable medium.

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