WO2024212059A1

WO2024212059A1 - Devices and methods for communication

Info

Publication number: WO2024212059A1
Application number: PCT/CN2023/087360
Authority: WO
Inventors: Gang Wang
Original assignee: Nec Corporation
Priority date: 2023-04-10
Filing date: 2023-04-10
Publication date: 2024-10-17

Abstract

Embodiments of the present disclosure provide a solution for Packet Data Convergence Protocol (PDCP) duplication enhancement based on importance. In the solution, a terminal device receives a duplication information indicating an activation state of PDCP duplication for a plurality of importance levels, the duplication information further indicating a Quality of Service (QoS) flow with which the plurality of importance levels is associated; determines, at least based on the duplication information, whether the PDCP duplication is activated for a first importance level; and if the PDCP duplication is activated for the first importance level, duplicate, by a PDCP entity of the terminal device, a first packet within the QoS flow for submitting to a plurality of radio link control (RLC) entities of the terminal device, the first packet having the first importance level.

Description

DEVICES AND METHODS FOR COMMUNICATION

FIELDS

Example embodiments of the present disclosure generally relate to the field of communication techniques and in particular, to devices and methods for Packet Data Convergence Protocol (PDCP) duplication enhancement based on importance of a packet.

BACKGROUND

In Release-18 (Rel-18) , a work item for eXtended Reality (XR) enhancement is ongoing. XR-awareness by terminal device and network device would improve the user experience, the New Radio (NR) system capacity in supporting XR services, and reduce the power consumption of terminal device.

Due to Internet Protocol (IP) segmentation or other reasons, a video frame in XR traffic may arrive at 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 payloads of a PDU set (e.g., a frame, video slice/tile) . Packets in such a PDU set may be decoded/handled as a whole. PDU set based Quality of Service (QoS) handling is studied and it would impact the design of RAN protocol.

In downlink, PDU set importance is provided by Core Node (CN) to identify the importance of a PDU set within a QoS flow. Similarly, in uplink, PDU set importance should also be provided to the Access Stratum (AS) layer. Based on the importance, PDU sets with higher importance can be duplicated to improve reliability.

SUMMARY

In general, embodiments of the present disclosure provide methods, devices and computer storage medium for PDCP duplication enhancement based on importance of a packet.

In a first aspect, there is provided a terminal device. The terminal device comprises: a processor configured to cause the terminal device to: receive, from a network device, a duplication information indicating an activation state of Packet Data Convergence Protocol (PDCP) duplication for a plurality of importance levels, the duplication information further indicating a Quality of Service (QoS) flow with which the plurality of importance levels is associated; determine, at least based on the duplication information, whether the PDCP duplication is activated for a first importance level of the plurality of importance levels; and in accordance with a determination that the PDCP duplication is activated for the first importance level, duplicate, by a PDCP entity of the terminal device, a first packet within the QoS flow for submitting to a plurality of radio link control (RLC) entities of the terminal device, the first packet having the first importance level.

In a second aspect, there is provided a network device. The network device comprises: a processor configured to cause the network device to: transmit, to a terminal device, a duplication information indicating an activation state of Packet Data Convergence Protocol (PDCP) duplication for a plurality of importance levels, the duplication information further indicating a Quality of Service (QoS) flow with which the plurality of importance levels is associated.

In a third aspect, there is provided a terminal device. The terminal device comprises: a processor configured to cause the terminal device to: in response to an event or a packet discarding indication from a network device, discard a first duplicated packet generated by Packet Data Convergence Protocol (PDCP) duplication of a first packet based on at least one of: an importance level of the first packet, a radio bearer associated with the first packet, or a radio link control (RLC) entity associated with the first duplicated packet.

In a fourth aspect, there is provided a network device. The network device comprises: a processor configured to cause the network device to transmit, to a terminal device, at least one of: a packet discard indication to discard at least one duplicated packet generated by Packet Data Convergence Protocol (PDCP) duplication of a packet, or a discard information indicating an order in which different duplicated packets are to be discarded.

In a fifth aspect, there is provided a communication method performed by a terminal device. The method comprises: receiving, from a network device, a duplication information indicating an activation state of Packet Data Convergence Protocol (PDCP) duplication for a plurality of importance levels, the duplication information further indicating a Quality of Service (QoS) flow with which the plurality of importance levels is associated; determining, at least based on the duplication information, whether the PDCP duplication is activated for a first importance level of the plurality of importance levels; and in accordance with a determination that the PDCP duplication is activated for the first importance level, duplicating, by a PDCP entity of the terminal device, a first packet within the QoS flow for submitting to a plurality of radio link control (RLC) entities of the terminal device, the first packet having the first importance level.

In a sixth aspect, there is provided a communication method performed by a network device. The method comprises: transmitting, to a terminal device, a duplication information indicating an activation state of Packet Data Convergence Protocol (PDCP) duplication for a plurality of importance levels, the duplication information further indicating a Quality of Service (QoS) flow with which the plurality of importance levels is associated.

In a seventh aspect, there is provided a communication method performed by a terminal device. The method comprises: in response to an event or a packet discard indication from a network device, discarding a first duplicated packet generated by Packet Data Convergence Protocol (PDCP) duplication of a first packet based on at least one of: an importance level of the first packet, a radio bearer associated with the first packet, or a radio link control (RLC) entity associated with the first duplicated packet.

In an eighth aspect, there is provided a communication method performed by a network device. The method comprises: transmitting, to a terminal device, at least one of: a packet discard indication to discard at least one duplicated packet generated by Packet Data Convergence Protocol (PDCP) duplication of a packet, or a discard information indicating an order in which different duplicated packets are to be discarded.

In a ninth aspect, there is provided a computer readable medium having instructions stored thereon, the instructions, when executed on at least one processor, causing the at least one processor to carry out the method according to any of the fifth to the eighth aspect.

Other features of the present disclosure will become easily comprehensible through the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

Through the more detailed description of some example embodiments of the present disclosure in the accompanying drawings, the above and other objects, features and advantages of the present disclosure will become more apparent, wherein:

FIG. 1 illustrates an example communication environment in which example embodiments of the present disclosure can be implemented;

FIG. 2 illustrates a signaling flow of packet duplication in accordance with some embodiments of the present disclosure;

FIG. 3 illustrates an example schematic diagram of packet paths in accordance with some embodiments of the present disclosure;

FIG. 4A illustrates a schematic diagram of an example format of duplication information via medium access control (MAC) control element (CE) in accordance with some embodiments of the present disclosure;

FIG. 4B illustrates a schematic diagram of another example format of duplication information via MAC CE in accordance with some embodiments of the present disclosure;

FIG. 4C illustrates a schematic diagram of another example format of duplication information format via MAC CE in accordance with some embodiments of the present disclosure;

FIG. 5A illustrates a schematic diagram of an example format of duplication information via PDCP Control PDU in accordance with some embodiments of the present disclosure;

FIG. 5B illustrates a schematic diagram of another example format of duplication information via PDCP Control PDU in accordance with some embodiments of the present disclosure;

FIG. 6A illustrates a schematic diagram of an example format of duplication information via SDAP Control PDU in accordance with some embodiments of the present disclosure;

FIG. 6B illustrates a schematic diagram of another example format of duplication information via SDAP control PDU in accordance with some embodiments of the present disclosure;

FIG. 7 illustrates a schematic diagram of another example format of duplication information associated with QoS flow in accordance with some embodiments of the present disclosure;

FIG. 8 illustrates another signaling flow of packet discard in accordance with some embodiments of the present disclosure;

FIG. 9 illustrates a flowchart of a method implemented at a terminal device according to some example embodiments of the present disclosure;

FIG. 10 illustrates a flowchart of a method implemented at a network device according to some example embodiments of the present disclosure;

FIG. 11 illustrates a flowchart of a method implemented at a terminal device according to some example embodiments of the present disclosure;

FIG. 12 illustrates a flowchart of a method implemented at a network device according to some example embodiments of the present disclosure;

FIG. 13 illustrates a simplified block diagram of an apparatus that is suitable for implementing example embodiments of the present disclosure.

Throughout the drawings, the same or similar reference numerals represent the same or similar element.

DETAILED DESCRIPTION

Principle of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. Embodiments described herein can be implemented in various manners other than the ones described below.

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

As used herein, the term ‘terminal device’ refers to any device having wireless or wired communication capabilities. Examples of the terminal device include, but not limited to, user equipment (UE) , personal computers, desktops, mobile phones, cellular phones, smart phones, personal digital assistants (PDAs) , portable computers, tablets, wearable devices, internet of things (IoT) devices, Ultra-reliable and Low Latency Communications (URLLC) devices, Internet of Everything (IoE) devices, machine type communication (MTC) devices, devices on vehicle for V2X communication where X means pedestrian, vehicle, or infrastructure/network, devices for Integrated Access and Backhaul (IAB) , Space borne vehicles or Air borne vehicles in Non-terrestrial networks (NTN) including Satellites and High Altitude Platforms (HAPs) encompassing Unmanned Aircraft Systems (UAS) , eXtended Reality (XR) devices including different types o f realities such as Augmented Reality (AR) , Mixed Reality (MR) and Virtual Reality (VR) , the unmanned aerial vehicle (UAV) commonly known as a drone which is an aircraft without any human pilot, devices on high speed train (HST) , or image capture devices such as digital cameras, sensors, gaming devices, music storage and playback appliances, or Internet appliances enabling wireless or wired Internet access and browsing and the like. The ‘terminal device’ can further has ‘multicast/broadcast’ feature, to support public safety and mission critical, V2X applications, transparent IPv4/IPv6 multicast delivery, IPTV, smart TV, radio services, software delivery over wireless, group communications and IoT applications. It may also incorporate one or multiple Subscriber Identity Module (SIM) as known as Multi-SIM. The term “terminal device” can be used interchangeably with a UE, a mobile station, a subscriber station, a mobile terminal, a user terminal or a wireless device.

The term “network device” refers to a device which is capable of providing or hosting a cell or coverage where terminal devices can communicate. Examples of a network device include, but not limited to, a Node B (NodeB or NB) , an evolved NodeB (eNodeB or eNB) , a next generation NodeB (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, a pico node, a reconfigurable intelligent surface (RIS) , and the like.

The terminal device or the network device may have Artificial intelligence (AI) or Machine learning capability. It generally includes a model which has been trained from numerous collected data for a specific function, and can be used to predict some information.

The terminal or the network device may work on several frequency ranges, e.g., FR1 (e.g., 450 MHz to 6000 MHz) , FR2 (e.g., 24.25GHz to 52.6GHz) , frequency band larger than 100 GHz as well as Tera Hertz (THz) . It can further work on licensed/unlicensed/shared spectrum. The terminal device may have more than one connection with the network devices under Multi-Radio Dual Connectivity (MR-DC) application scenario. The terminal device or the network device can work on full duplex, flexible duplex and cross division duplex modes.

The embodiments of the present disclosure may be performed in test equipment, e.g., signal generator, signal analyzer, spectrum analyzer, network analyzer, test terminal device, test network device, channel emulator. In some embodiments, the terminal device may be connected with a first network device and a second network device. One of the first network device and the second network device may be a master node and the other one may be a secondary node. The first network device and the second network device may use different radio access technologies (RATs) . In some embodiments, the first network device may be a first RAT device and the second network device may be a second RAT device. In some embodiments, the first RAT device is eNB and the second RAT device is gNB. Information related with different RATs may be transmitted to the terminal device from at least one of the first network device or the second network device. In some embodiments, first information may be transmitted to the terminal device from the first network device and second information may be transmitted to the terminal device from the second network device directly or via the first network device. In some embodiments, information related with configuration for the terminal device configured by the second network device may be transmitted from the second network device via the first network device. Information related with reconfiguration for the terminal device configured by the second network device may be transmitted to the terminal device from the second network device directly or via the first network device.

As used herein, the singular forms ‘a’ , ‘an’ and ‘the’ are intended to include the plural forms as well, unless the context clearly indicates otherwise. The term ‘includes’ and its variants are to be read as open terms that mean ‘includes, but is not limited to. ’ The term ‘based on’ is to be read as ‘at least in part based on. ’ The term ‘one embodiment’ and ‘an embodiment’ are to be read as ‘at least one embodiment. ’ The term ‘another embodiment’ is to be read as ‘at least one other embodiment. ’ The terms ‘first, ’ ‘second, ’ and the like may refer to different or same objects. Other definitions, explicit and implicit, may be included below.

In some examples, values, procedures, or apparatus are referred to as ‘best, ’ ‘lowest, ’ ‘highest, ’ ‘minimum, ’ ‘maximum, ’ or the like. It will be appreciated that such descriptions are intended to indicate that a selection among many used functional alternatives can be made, and such selections need not be better, smaller, higher, or otherwise preferable to other selections.

As used herein, the term “resource, ” “transmission resource, ” “uplink resource, ” or “downlink resource” may refer to any resource for performing a communication, such as a resource in time domain, a resource in frequency domain, a resource in space domain, a resource in code domain, or any other resource enabling a communication, and the like. In the following, unless explicitly stated, a resource in both frequency domain and time domain will be used as an example of a transmission resource for describing some example embodiments of the present disclosure. It is noted that example embodiments of the present disclosure are equally applicable to other resources in other domains.

As used herein, the term “PDU set” may comprise one or more PDUs for carrying the payload of one unit of information generated at the application level (e.g., a frame or video slice for eXtended Reality Multimedia enhancement (XRM) services) . In some implementations, all PDUs in a PDU set are needed by the application layer to use the corresponding unit of information. In other implementations, the application layer may recover parts of or all the information unit, when some PDUs are missing.

As used herein, the term “packet” may refer to a PDU, one or more PDUs, a service data unit (SDU) , one or more SDUs, a PDU set, etc. In the following, some embodiments may be described with respect to the PDU or PDU set. However, this is example without limitation.

As used herein, the term “Data Burst” may refer to a set of PDUs generated and sent by the application in a short period. A Data Burst may comprise one or more PDU sets.

As used herein, the term “radio bearer (RB) ” used herein may refer to a tunnel that may take and carry information from one end to another end. The term “data radio bearer (DRB) ” used herein may refer to an RB that is established for transmissions of data plane packets. The term “signaling radio bearer (SRB) ” used herein may refer to an RB that is used for transmissions of signaling message, for example, radio resource control (RRC) message, non-access stratum (NAS) message.

In the present disclosure, the terms “importance” and “importance level” may be used interchangeably. As one example, a value of importance may be used for indicating an importance level. Moreover, the embodiments described with respect to “importance” or “importance level” may be applied to “priority” or “priority level” . Therefore, the terms “importance” , “importance level” , “priority” and “priority level” may be used interchangeably.

Principles and implementations of the present disclosure will be described in detail below with reference to the figures.

FIG. 1 illustrates a schematic diagram of an example communication environment 100 in which example embodiments of the present disclosure can be implemented. In the communication environment 100, a plurality of communication devices, including a terminal device 110 and a network device 120, can communicate with each other.

In the example of FIG. 1, the terminal device 110 may be a UE and the network device 120 may be a base station serving the UE. The serving area of the network device 120 may be called a cell 102. In the present disclosure, the terms “terminal device” and “UE” may be used interchangeably, and the terms “network device” , “base station” and “network (NW) ” may be used interchangeably.

It is to be understood that the number of devices and their connections shown in FIG. 1 are only for the purpose of illustration without suggesting any limitation. The communication environment 100 may include any suitable number of devices configured to implementing example embodiments of the present disclosure. Although not shown, it would be appreciated that one or more additional devices may be located in the cell 102, and one or more additional cells may be deployed in the communication environment 100.

In some example embodiments, a link from the network device 120 to the terminal device 110 is referred to as a DL, while a link from the terminal device 110 to the network device 120 is referred to as an UL. In DL, the network device 120 is a TX device (or a transmitter) and the terminal device 110 is a RX device (or a receiver) . In UL, the terminal device 110 is a TX device (or a transmitter) and the network device 120 is a RX device (or a receiver) .

The communications in the communication environment 100 may conform to any suitable standards including, but not limited to, Global System for Mobile Communications (GSM) , Long Term Evolution (LTE) , LTE-Evolution, LTE-Advanced (LTE-A) , New Radio (NR) , Wideband Code Division Multiple Access (WCDMA) , Code Division Multiple Access (CDMA) , GSM EDGE Radio Access Network (GERAN) , Machine Type Communication (MTC) and the like. The embodiments of the present disclosure may be performed according to any generation communication protocols either currently known or to be developed in the future. Examples of the communication protocols include, but not limited to, the first generation (1G) , the second generation (2G) , 2.5G, 2.75G, the third generation (3G) , the fourth generation (4G) , 4.5G, the fifth generation (5G) communication protocols, 5.5G, 5G-Advanced networks, or the sixth generation (6G) networks.

In the example of FIG. 1, the terminal device 110 may comprise one PDCP entity 130 and one or more Radio Link Control (RLC) entities. If duplication is configured for an RB by RRC signalling, the terminal device 110 may comprise at least two RLC entities to handle the duplicated packets, such as a RLC entity 140-1 and a RLC entity 140-2 (which are also referred to as a primary RLC and a secondary RLC, or RLC entity 140 individually) . The logical channel (LCH) corresponding to the RLC entity 140-1 is referred to as the primary LCH, and the LCH (s) corresponding to the RLC entity 140-2 is referred to as the secondary LCH (s) .

In some embodiments, all RLC entities have the same RLC mode. Duplication at PDCP therefore consists in submitting the same packets multiple times: once to each activated RLC entity for the RB. With multiple independent transmi ssion paths, packet duplication therefore increases reliability, reduces latency and is especially beneficial for Ultra Reliable and Low Latency Communication (URLLC) services.

When duplication is configured for a DRB, RRC also sets the state of PDCP duplication (either activated or deactivated) at the time of (re-) configuration. After the (re) configuration, the PDCP duplication state can then be dynamically controlled by means of a Medium Access Control (MAC) Control Element (CE) and in Dual Connectivity (DC) . The terminal device applies the MAC CE commands regardless of their origin (Master Cell Group, MCG, or Secondary Cell Group, SCG) .

When duplication is configured for an SRB, the state is always active and cannot be dynamically controlled. When configuring duplication for a DRB with more than one secondary RLC entity, RRC also sets the state of each of them (i.e., either activated or deactivated) . Subsequently, a MAC CE can be used to dynamically control whether each of the configured secondary RLC entities for a DRB should be activated or deactivated, i.e., which of the RLC entities shall be used for duplicate transmission.

In some embodiments, the primary RLC entity cannot be deactivated. When duplication is deactivated for a DRB, all secondary RLC entities associated to this DRB are deactivated. When a secondary RLC entity is deactivated, it is not re-established, the Hybrid Automatic Repeat Quest (HARQ) buffers are not flushed, and the transmitting PDCP entity should indicate to the secondary RLC entity to discard all duplicated PDCP PDUs.

It is required that PDCP Control PDUs should not be duplicated and always be submitted to the primary RLC entity.

When activating duplication for a DRB, radio access network (RAN) may ensure that at least one serving cell is activated for each LCH associated with an activated RLC entity of the DRB. When the deactivation of SCells leaves and there is no serving cell activated for a LCH of the DRB, NG-RAN may ensure that duplication is also deactivated for the RLC entity associated with the LCH.

When duplication is activated, the original PDCP PDU and the corresponding duplicate (s) may not be transmitted on the same carrier. The LCHs of an RB configured with duplication may either belong to the same MAC entity (referred to as Carrier Aggregation (CA) duplication) or to different ones (referred to as DC duplication) . CA duplication can also be configured in either or both of the MAC entities together with DC duplication when duplication over more than two RLC entities is configured for the RB. In CA duplication, LCH mapping restrictions are used in a MAC entity to ensure that the different LCHs of an RB in the MAC entity are not sent on the same carrier. When CA duplication is configured for an SRB, one of the LCHs associated to the SRB is mapped to Special Cell (SpCell) , e.g., Primary Cell (PCell) and Primary Secondary Cell (PSCell) .

When CA duplication is deactivated for a DRB in a MAC entity (i.e., none or only one of RLC entities of the DRB in the MAC entity remains activated) , the logical channel mapping restrictions of the logical channels of the DRB are lifted for as long as CA duplication remains deactivated for the DRB in the MAC entity.

When an RLC entity acknowledges the transmission of a PDCP PDU, the PDCP entity may indicate to the other RLC entity (ies) to discard it. In addition, in case of CA duplication, when an RLC entity restricted to only SCell (s) reaches the maximum number of retransmissions for a PDCP PDU, the terminal device 110 informs the network device 120 without triggering the RLF.

The Duplication Activation/Deactivation MAC CE of one octet is identified by a MAC subheader with Logical Channel Identity (LCID) . It has a fixed size and consists of a single octet containing eight D-fields (e.g., D0-D7) . The Duplication Activation/Deactivation MAC CE is defined, for a MAC entity. The Di field indicates the activation/deactivation status of the PDCP duplication of DRB i, where i is the ascending order of the DRB ID among the DRBs configured with PDCP duplication and with RLC entity (ies) associated with this MAC entity. The Di field is set to 1 to indicate that the PDCP duplication of DRB i shall be activated. The Di field is set to 0 to indicate that the PDCP duplication of DRB i shall be deactivated. It is noted that the Duplication Activation/Deactivation MAC CE is not used if a DRB is configured with more than two RLC entities, i.e., with more than two RLC-DRB.

The Duplication RLC Activation/Deactivation MAC CE is identified by a MAC subheader with extended Logical Channel Identity (eLCID) . It has a fixed size and consists of a single octet. The DRB ID field indicates the identity of DRB for which the MAC CE applies. The length of the field may be 5 bits. The RLCi (e.g., RLC0-RLC2) field indicates the activation/deactivation status of PDCP duplication for the RLC entity i, where i is ascending order of LCH ID of secondary RLC entities in the order of MCG and SCG, for the DRB. The RLCi field is set to 1 to indicate that the PDCP duplication for the RLC entity i shall be activated. The RLCi field is set to 0 to indicate that the PDCP duplication for the RLC entity i shall be deactivated.

The following PDU set related information is identified by User Plane Function (UPF) to support PDU set based handling: PDU set Sequence Number (SN) , End PDU of the PDU set, PDU SN within a PDU set, PDU set size in bytes. In cases, it is up to an application to decide whether to send PDU set size in bytes or not.

The PDU set importance parameter may be used to identify the importance of a PDU set within a QoS flow. RAN may use it for PDU set level packet discarding in presence of congestion.

The following PDU set QoS parameters are defined to support PDU set handling: PDU Set Error Rate (PSER) , PDU set Delay Budget (PSDB) , and whether all PDUs are needed for the usage of PDU set by application layer (PDU set Integrated Indication) .

The PSER defines an upper bound for the rate of PDU sets that have been processed by the sender of a link layer protocol (e.g., RLC in RAN of a 3GPP access) but that are not successfully delivered by the corresponding receiver to the upper layer (e.g., PDCP in RAN of a 3GPP access) . Thus, the PSER defines an upper bound for a rate of non-congestion related packet losses. The purpose of the PSER is to allow for appropriate link layer protocol configurations (e.g., RLC and HARQ in RAN of a 3GPP access) . For every 5G QoS Identifier (5QI) the value of the PSER is the same in UL and DL. If any PDU within the PDU set is not successfully transmitted, the PDU set is treated as error. It is noted that the definitions of PSER can be revisited.

The PSDB defines an upper bound for the delay that a PDU set may experience for the transfer between the UE and the N6 termination point at the UPF, i.e., time between reception of the first PDU and the successful delivery of the last arrived PDU of a PDU set. PSDB applies to the DL PDU set received by the UPF over the N6 interface, and to the UL PDU set sent by the terminal device 110. For a certain 5QI the value of the PSDB is the same in UL and DL. It is noted that the definitions of PSDB can be revisited. It is also noted that a PDU set is considered as successfully delivered when all PDUs of a PDU set are delivered successfully.

To enable support for PSDB, it is assumed that there is a maximum duration threshold for inter arrival time between PDUs and first arrived PDU within the PDU set as per Service Level Agreement (SLA) or pre-configuration. How to handle the case that the maximum duration threshold is not met needs to be discussed. PSDB is an optional parameter. If Policy Control function (PCF) has sufficient information to determine the PSDB, the PSDB is used to support the configuration of scheduling and link layer functions.

New 5G QoS parameters for PDU set concept may be defined. The PDU set comprises of one or more PDUs for which the following PDU set QoS parameters are applicable: PDU set Delay Budget (PSDB) , PDU set Error Rate (PSER) , PDU set Integrated handling Indication (PSIHI) .

PDU set importance that is conveyed on per-PDU set basis may be defined. All the PDU sets within one QoS flow should apply the same PSER, PSDB and PSIHI. The PDU set importance of the different PDU sets within one QoS flow can be different.

Different types of PDU set may be mapped into the same QoS flow if their PDU set QoS parameters (and other QoS characteristics, e.g., 5QI, ARP) are the same. One QoS flow is associated with one PSER and one PSDB at any time. Further, different PDU sets within one QoS flow may be associated with different “PDU set importance” information.

In some cases, the PDU set information “PDU set importance” may be provided by the UPF to Next Generation Ratio Access Network (NG-RAN) via General Packet Radio Services (GPRS) Tunnelling Protocol for the user plane (GTP-U) header of user plane packet. It may be used by NG-RAN for PDU set level packet discarding in presence of congestion.

The current PDCP duplication mechanism include: ⅰ) PDCP duplication is configured with an RB as granularity. Once the RB is configured with PDCP duplication function, all data packets in the RB shall be duplicated when the PDCP duplication function is activated. ⅱ) For XR traffic, different PDU sets within one QoS flow (which may be mapped to the same DRB) may be associated with different “PDU set importance” information. PDU sets with different importance may have different reliability requirements, and hence, PDU sets with higher importance may apply PDCP duplication, while lower importance PDU sets do not apply PDCP duplication, thereby increasing the reliability of higher importance PDU set, and increasing the utilization of resources. ⅲ) If congestion or other issues happen, PDCP duplication (for DRB, RLC, or importance) may be deactivated, or duplicated packets may be discarded with a higher priority.

Given the above, some issues need to be solved. These issues at least include: ⅰ) how importance-based PDCP duplication is performed, ⅱ) how to configure/activate/deactivate importance-based PDCP duplication, ⅲ) how to calculate data volume when importance-based PDCP duplication is activated/deactivated, ⅳ) how to discard duplicated packets when congestion or other conditions happens.

Reference is made to FIG. 2, which illustrates a signaling flow 200 of packet duplication in accordance with some embodiments of the present disclosure. For the purposes of discussion, the signaling flow 200 will be discussed with reference to FIG. 1, for example, by using the terminal device 110 and the network device 120.

As shown, the network device 120 transmits (202) , to the terminal device 110, a duplication information which indicates an activation state of PDCP duplication for a plurality of importance levels. In one embodiment, the duplication information may indicate an activation state of PDCP duplication for a plurality of values. The duplication information further indicates a QoS flow with which the plurality of importance levels is associated. For example, the plurality of importance levels may be associated with a special QoS flow. The duplication information may be included in an activation/deactivation command. Multiple QoS flows may be mapped to the same DRB. QoS Flow ID (QFI) may be indicated to the terminal device 110 when an activation/deactivation command is sent to the terminal device 110.

The terminal device 110 receives (204) the duplication information from the network device 120 accordingly. At least based on the duplication information, the terminal device 110 determines (206) whether the PDCP duplication is activated or deactivated for an importance level of the plurality of importance levels.

If the PDCP duplication is activated for a first importance level, the terminal device 110 duplicates (208) a first packet within the QoS flow for submitting to a plurality of RLC entities of the terminal device 110. The first packet is set to/configured with the first importance level. For example, the PDCP entity 130 of the terminal device 110 duplicates the first packet for submitting to the RLC entities 140.

A packet, such as SDU, PDU or PDU set, may have different importance levels (which are also referred to as priorities) . In an example, if PDCP duplication for an importance level is activated, the terminal device 110 (or the PDCP entity 130) may submit the same PDCP PDUs (with the importance level) multiple times: once to each activated RLC entity 140 for the RB.

In some embodiments, the terminal device 110 may determine whether the duplication information indicate an activation of the PDCP duplication for the first importance level. Further, the terminal device 110 may determine whether the PDCP duplication is activated for an RB associated with the QoS flow. If the duplication information indicates the activation of the PDCP duplication for the first importance level and/or the PDCP duplication is activated for the RB, the terminal device 110 determine that the PDCP duplication is activated for the first importance level.

For example, the activation/deactivation may be performed per DRB or per QoS flow. If duplication is deactivated for a DRB, all importance-based PDCP duplications associated with this DRB are deactivated.

In some embodiments, the terminal device 110 (or the PDCP entity 130) may indicate a secondary RLC entity of the plurality of RLC entities to discard a duplicated packet corresponding to the first packet if the PDCP duplication is deactivated for the first importance level. In an example, if an importance level is deactivated, the transmitting PDCP entity may indicate the associated secondary RLC entity to discard all duplicated PDCP PDUs.

In some embodiments, at least based on the duplication information, the terminal device 110 may determine whether the PDCP duplication is deactivated for a second importance level of the plurality of importance levels. If the PDCP duplication is deactivated for the second importance level, the terminal device 110 (or the PDCP entity 130) may submit a second packet within the QoS flow to a primary RLC entity without duplication of the second packet. The second packet may be set to or configured with the second importance level.

In an example, if PDCP duplication for an importance level is deactivated, PDCP PDUs (with the importance level) may be submitted to the RLC entity 140, e.g., the primary RLC entity. In this situation, split-bearer may not be considered.

Reference is now made to FIG. 3, which illustrates an example schematic diagram 300 of packet paths in accordance with some embodiments of the present disclosure. The packets 310 whose importance level is activated for PDCP duplication are submitted to the primary RLC entity and the secondary RLC entity by the PDCP entity 130. The packets 320 whose importance level is deactivated for PDCP duplication are submitted to the primary RLC entity by the PDCP entity 130 without submitting to the secondary RLC entity.

In an example, for the PDCP layer, the transmitting PDCP entity is associated with at least two RLC entities, e.g., the RLC entity 140-1 and the RLC entity 140-2. If the PDCP duplication is activated for the importance level and the PDCP PDU is a PDCP Data PDU, the terminal device 110 may duplicate the PDCP Data PDU with the importance level and submit the PDCP Data PDU to the associated RLC entities activated for PDCP duplication. Otherwise, the terminal device 110 may submit the PDCP Control PDU to the primary RLC entity, that is, the RLC entity 140-1.

The procedure of importance-based PDCP duplication is associated with MAC layer and PDCP layer. In MAC layer, the PDCP duplication for all or a subset of associated importance levels is activated and deactivated by receiving a MAC CE (e.g., Duplication Importance Activation/Deactivation MAC CE) and/or an indication by RRC.

In an example, if a MAC CE (e.g., Duplication Importance Activation/Deactivation MAC CE) is received activating PDCP duplication for associated importance level (e.g., of the DRB or QoS flow) , the terminal device 110 may indicate the activation of PDCP duplication for the indicated importance level to upper layer (s) (e.g., PDCP or SDAP layer) .

In an example, if a MAC CE (e.g., Duplication Importance Activation/Deactivation MAC CE) is received deactivating PDCP duplication for associated importance level (e.g., of the DRB or QoS flow) , the terminal device 110 may indicate the deactivation of PDCP duplication for the indicated importance level to upper layer (s) (e.g., PDCP or SDAP layer) .

In an example, for PDCP layer, if the indication of activation of importance-based PDCP duplication has been received from a lower layer (e.g., MAC layer) , or a PDCP/SDAP control PDU indicates activation of importance-based PDCP duplication has been received, the PDCP entity 130 may activate the PDCP duplication for the indicated associated importance level.

In an example, if the indication of deactivation of importance-based PDCP duplication has been received from a lower layer (e.g., MAC layer) , or a PDCP/SDAP control PDU indicates deactivation of importance-based PDCP duplication has been received, the PDCP entity 130 may deactivate the PDCP duplication for the indicated associated importance level.

In some embodiments, the terminal device 110 may transmit assistance information to the network device 120. The assistance information comprises at least one of: the number of the plurality of importance levels, or a suggestion on one or more importance levels for which the PDCP duplication is activated.

In an example, the terminal device 110 may assist the network device 120 to configure/activate/deactivate importance-based PDCP duplication. The terminal device 110 may indicate at least one of the following information to the network device 120 (e.g., via UE Assistance Information) : the importance levels which are suggested to be activated for PDCP duplication, the number of importance levels.

In order to indicate the importance-based duplication, in some embodiments, the duplication information comprises a plurality of fields corresponding to the plurality of importance levels. A field of the plurality of fields indicates the activation state for the corresponding importance level. For example, a bitmap may be used, as described below. In one embodiment, the duplication information comprises an indication of a reference level for partitioning the plurality of importance levels according to whether the PDCP duplication is activated. For example, an importance level may be indicated as a reference to the terminal device 110, as described below.

The duplication information may be included in any suitable signaling. In some embodiments, the duplication information may be received in an RRC signaling. When configuring duplication for an importance level, RRC may set the state of PDCP duplication (either activated or deactivated) for each importance level at the time of (re-) configuration.

In an example, each importance level may correspond to a bit (e.g., a bit in importanceDuplicationState) . If a bit for an importance level is set to 1 (or true) , the PDCP duplication for the importance level is activated. If the bit for an importance level is set to 0 (or false) , the PDCP duplication for the importance level is deactivated.

An importance value or level may be configurable as a reference. The importance level (s) equal to or higher than the configured importance value may be activated for PDCP duplication. In an example, 4 importance levels (0～3) are defined, where 0 refers to the highest importance level and 3 refers to the lowest importance level. If the configured value is 1, the importance level with values 0 and 1 shall be activated for PDCP duplication, and the importance level with values 2 and 3 shall be deactivated for PDCP duplication.

In some embodiments, the QFI with which the importance levels are associated may also be configured. For example, a list of ImportanceDuplication may be configured by the network device 120.

In some embodiments, the duplication information may be received in a MAC CE. After the duplication configuration, the PDCP duplication state for an importance level may be dynamically controlled by means of a MAC CE. The related MAC CE (e.g., Duplication Importance Activation/Deactivation MAC CE, which may be a newly-introduced) may include at least one of the following fields: DRB ID field, Importance i (or IMPi) field, importance level field (or importance field) , QFI field.

The DRB ID field may indicate the identity of DRB for which the MAC CE applies.

The IMPi field may indicate the activation/deactivation status of PDCP duplication for the importance i, where i is the importance value or the ascending order of importance level, for the DRB (or for the PDU set/QoS flow) . The IMPi field is set to 1 to indicate that the PDCP duplication for the IMPi may be activated. The IMPi field is set to 0 to indicate that the PDCP duplication for the IMPi may be deactivated.

The importance level field may indicate that importance level (s) equal to or higher than the field value may be activated for PDCP duplication. For example, if 4 importance levels (0～3) are defined, where 0 refers to the highest importance level and 3 refers to the lowest importance level. If the importance level field value is 1, then importance level with values 0 and 1 shall be activated for PDCP duplication, and importance level with values 2 and 3 shall be deactivated for PDCP duplication.

The field QFI may indicate the ID of the QoS flow with which the importance levels are associated. In some embodiments, the MAC CE further comprises an identification of an RB associated with the QoS flow.

Reference is now made to FIG. 4A, which illustrates a schematic diagram of an example format 400A of duplication information via MAC CE in accordance with some embodiments of the present disclosure. The format 400A comprises fields for configuring three importance levels. In one embodiment, the format 400A comprises an IMP₀ field 408, an IMP₁ field 406 and an IMP₂ field 404, a DRB ID field 402 (and/or QFI field) , wherein the DRB ID field 402 contains five bits.

In an example, activation/deactivation state of PDCP duplication for the RLC entity i and importance i can be mixed together in the same MAC CE. Reference is now made to FIG. 4B, which illustrates a schematic diagram of another example format 400B of duplication information via MAC CE in accordance with some embodiments of the present disclosure. The format 400B may represent the duplication RLC and the importance activation/deactivation MAC CE for four importance levels as an example. In one embodiment, the format 400B comprises a DRB ID field 410 (and/or QFI field) , a RLC₀ field 416, a RLC₁ field 414, a RLC₂ field 412, an IMP₀ field 424, an IMP₁ field 422, an IMP₂ field 420, an IMP₃ field 418 and reserved fields (R fields) , wherein the DRB ID field 402 contains five Bits.

Reference is now made to FIG. 4C, which illustrates a schematic diagram of another example format 400C of duplication information via MAC CE in accordance with some embodiments of the present disclosure. The format 400C comprises a DRB ID field 426 (and/or QFI field) and an Importance field 428, wherein the DRB ID field 402 contains five bits and the Importance field contains three bits.

In some embodiments, the duplication information may be received in a PDCP control PDU. After the duplication configuration, the PDCP duplication state for an importance level can be dynamically controlled by means of a PDCP Control PDU. The new PDCP Control PDU may include at least one of the following fields: new PDU Type field, Importance i (or IMPi) field, importance level field (or importance field) , QFI field.

In an example, a PDU type field may comprise a Bit value “000” for PDCP status report, a Bit value “001” for Interspersed Robust Header Compression (ROHC) feedback, a Bit value “010” for Ethernet Header Compression (EHC) feedback and a Bit value “011” for Uplink Data Compression (UDC) feedback. The PDU Type field may further comprise a new value, for example, a Bit value “100” for importance based PDCP duplication activation/deactivation.

The IMPi field may indicate the activation/deactivation state of PDCP duplication for the Importance i, where i is the importance value or the ascending order of importance level, for the DRB (or for the PDU set/QoS flow) . The IMPi field is set to 1 to indicate that the PDCP duplication for the importance i may be activated. The IMPi field is set to 0 to indicate that the PDCP duplication for the importance i may be deactivated.

The importance level field may indicate that the importance level (s) equal to or higher than the field value may be activated for PDCP duplication. For example, if 4 importance levels (0～3) are defined, where 0 refers to the highest importance level and 3 refers to the lowest importance level. If the filed value is 1, then importance level with values 0 and 1 shall be activated for PDCP duplication, and an importance level with values 2 and 3 shall be deactivated for PDCP duplication.

In an example, the QFI field may indicate the ID of the QoS flow with which the importance levels are associated. Additionally, the QFI field may be optional.

Reference is now made to FIG. 5A, which illustrates a schematic diagram of an example format 500A of duplication information via PDCP Control PDU in accordance with some embodiments of the present disclosure. The format 500A comprises a D/C field 502, a PDU type field 504, an IMP₀ field 512, an IMP₁ field 510, an IMP₂ field 508 and an IMP₃ field 506, wherein the PDU type field 504 contains three bits.

Reference is now made to FIG. 5B, which illustrates a schematic diagram of another example format 500B of duplication information via PDCP Control PDU in accordance with some embodiments of the present disclosure. The format 500B comprises a D/C field 502, a PDU type field 504 and an Importance field 514, wherein the PDU type field 504 contains three bits and the Importance field 514 contains four bits.

In one embodiment, the duplication information may be received in an SDAP control PDU. After the duplication configuration, the PDCP duplication state for an importance level may be dynamically controlled by means of an SDAP control PDU. The (new) SDAP control PDU may include at least one of the following fields: (new) PDU Type field, QFI field, importance i (or IMPi) field, importance level field (or importance field) .

A PDU type field with a specific value may indicate that the PDU is used for activation/deactivation of importance-based PDCP duplication.

The QFI field may indicate the ID of the QoS flow with which the importance levels are associated. It is noted that SDAP layer may indicate QFI to lower layer (e.g., PDCP layer) for the PDCP duplication handling.

The IMPi field may indicate the activation/deactivation state of PDCP duplication for the importance i, where i is the importance value or the ascending order of importance level, for the QoS flow (or for the PDU set) . The IMPi field is set to 1 to indicate that the PDCP duplication for the IMPi shall be activated. The IMPi field is set to 0 to indicate that the PDCP duplication for the IMPi shall be deactivated.

The importance field may indicate that the importance level (s) equal to or higher than the field value shall be activated for PDCP duplication. For example, if 4 importance levels (0～3) are defined, 0 is the highest importance level and 3 is the lowest importance level. If the filed value is 1, then importance level with values 0 and 1 shall be activated for PDCP duplication, and the importance level with values 2 and 3 shall be deactivated for PDCP duplication.

Reference is now made to FIG. 6A, which illustrates a schematic diagram of an example format 600A of duplication information via SDAP Control PDU in accordance with some embodiments of the present disclosure. The format 600A for four importance levels as an example comprises a D/C field 602, a QFI field 604, a PDU Type field 606, an IMP₀ field 614, an IMP₁ field 612, an IMP₂ field 610 and an IMP₃ field 608, and a reserved field (R field) , where the QFI field 604 contains six bits and the PDU Type field 606 contains four bits.

Reference is now made to FIG. 6B, which illustrates a schematic diagram of another example format 600B of duplication information via SDAP control PDU in accordance with some embodiments of the present disclosure. The format 600B comprises a D/C field 602, a QFI field 604, a PDU Type field 606, an importance field 616, and a reserved field (R field) , wherein the QFI field 604 contains six bits and the PDU Type field 606 contains four bits.

In some embodiments, for each importance level of the plurality of importance levels, the duplication information further indicates whether the PDCP duplication is activated for each secondary RLC entity. In some embodiments, the plurality of RLC entity may comprise a primary RLC entity and at least one RLC entity for which the PDCP duplication for the first importance level is activated.

If packets (e.g., SDUs/PDUs/PDU sets) with different importance levels are mapped to different LCHs, the network device 120 may indicate the terminal device 110 to activate/deactivate importance-based PDCP duplication (e.g., via RRC/MAC CE/PDCP Control PDU/SDAP Control PDU) . At least one of the following fields may be configured or sent to the terminal device 110: DRB ID or QFI field, impotence i (or IMPi) field, importance level field (or importance field) , RLCi field.

In an example, the DRB ID or QFI field may indicate the ID of the QoS flow or DRB with which the importance levels are associated.

In an example, the IMPi field may indicate the activation/deactivation status of PDCP duplication for the importance i, where i is the importance value or the ascending order of importance level, for the QoS flow (or for the PDU set) . The IMPi field is set to 1 to indicate that the PDCP duplication for the importance i shall be activated. The IMPi field is set to 0 to indicate that the PDCP duplication for the importance i shall be deactivated.

In an example, the importance level (s) equal to or higher than the field value shall be activated for PDCP duplication. For example, if 4 importance levels (0～3) are defined, 0 is the highest importance level and 3 is the lowest importance level. If the filed value is 1, then importance level with values 0 and 1 shall be activated for PDCP duplication, and the importance level with values 2 and 3 shall be deactivated for PDCP duplication.

In an example, the RLCi field may indicate the activation/deactivation status of PDCP duplication for the RLC entity i where i is ascending order of logical channel ID of secondary RLC entities in the order of MCG and SCG, for the DRB or the importance. The RLCi field is set to 1 to indicate that the PDCP duplication for the RLC entity i shall be activated. The RLCi field is set to 0 to indicate that the PDCP duplication for the RLC entity i shall be deactivated. It is noted that one or more secondary RLC entities may be associated with a specific importance.

Reference is now made to FIG. 7, which illustrates a schematic diagram of another example format 700 of duplication associated with QoS flow in accordance with some embodiments of the present disclosure. The format 700 for four importance levels may indicate the duplication RLC. For example, the format 700 comprises a DRB ID field 702 (and/or QFI field) and reserved fields (R fields) in the first eight bits 704, two IMPi (e.g., IMP₀, IMP₁) field and six RLCi fields (i.e., two RLC₀, two RLC₁ and two RLC₂) in the second eight bits 706, and two IMPi (e.g., IMP₂, IMP₃) fields and six RLCi fields (i.e., two RLC₀, two RLC₁ and two RLC₂) in the third eight bits 708, where the DRB ID field 702 contains five bits.

In general, in accordance with some embodiments of the present disclosure, different PDUs/PDU sets within one QoS flow/DRB may be associated with different “PDU set importance” information. For PDUs/PDU sets with a higher importance, PDCP duplication can be applied to improve the reliability of higher importance PDUs/PDU sets. PDCP duplication (for DRB, RLC entity, or importance level) may be deactivated when congestion or other conditions happen. Therefore, the reliability of PDUs/PDU sets with higher importance may be improved and the utilization of resources may be increased.

It is to be understood that the length of any field described above is merely for purpose of illustration without any limitation. In embodiments of the present disclosure, a field may have any suitable length. Moreover, the order of different fields described above is merely for purpose of illustration without any limitation. In embodiments of the present disclosure, different fields may be arranged in any suitable manner.

Given the PDCP duplication may be activated for an importance level but deactivated for another importance level, PDCP data volume calculation may be performed by taking the importance based PDCP duplication into consideration.

Reference is made back to the flow 200. In some embodiments, the plurality of RLC entities comprises a primary RLC entity and at least a first RLC entity other than the primary RLC entity, and the PDCP entity 130 may indicate, to a first MAC entity, a first PDCP data volume corresponding to the first importance level. The first MAC entity is associated with the first RLC entity, and the first PDCP data volume excludes a data volume of a control packet.

In some embodiments, the PDCP entity 130 may indicate, to a second MAC entity, a second PDCP data volume corresponding to the first importance level as a predetermine value (for example, 0) . The second MAC entity is associated with a second RLC entity deactivated for the PDCP duplication.

Data volume may be calculated in the PDCP entity 130. In an example, if the PDCP duplication is activated for an importance, the PDCP entity 130 may indicate the PDCP data volume to the MAC entity associated with the primary RLC entity. The PDCP entity 130 may indicate the PDCP data volume corresponding to the importance (excluding the PDCP control PDU) to the MAC entity associated with the RLC entity other than the primary RLC entity activated for PDCP duplication. The PDCP entity 130 may indicate the PDCP data volume corresponding to the importance as 0 to the MAC entity associated with RLC entity deactivated for PDCP duplication.

In some embodiments, the PDCP duplication is deactivated for the second importance level, and the PDCP entity 130 may indicate, to a third MAC entity, a third PDCP data volume corresponding to the second importance level as a predetermine value (for example, 0) . The third MAC entity is associated with a third RLC entity other than the primary RLC entity. In some embodiments, the PDCP entity 130 may indicate, to a fourth MAC entity, a fourth PDCP data volume corresponding to the second importance level as the predetermine value. The fourth MAC entity is associated with a fourth RLC entity deactivated for the PDCP duplication.

In an example, if the PDCP duplication is deactivated for an importance, the PDCP entity may indicate the PDCP data volume to the MAC entity associated with the primary RLC entity. Further, the PDCP entity may indicate the PDCP data volume corresponding to the importance as 0 to the MAC entity associated with the RLC entity other than the primary RLC entity activated for PDCP duplication. The PDCP entity may indicate the PDCP data volume corresponding to the importance as 0 to the MAC entity associated with RLC entity deactivated for PDCP duplication.

In general, in accordance with some embodiments of the present disclosure, when performing PDCP data volume calculation, if PDCP duplication is activated for an importance level, the packet with the importance level shall be included in the PDCP data volume associated with the activated RLC entity. If PDCP duplication is deactivated for an importance level, the packet with the importance level shall be excluded in the PDCP data volume associated with the activated secondary RLC entity. Therefore, PDCP data volume may be calculated as expected.

In some scenarios, congestion or other issue may occur and one or more packets may expect to be discarded. Reference is made to FIG. 8, which illustrates a signaling flow 800 of packet discard in accordance with some embodiments of the present disclosure. For the purposes of discussion, the signaling flow 800 will be discussed with reference to FIG. 1, for example, by using the terminal device 110 and the network device 120.

In some embodiments, the terminal device 110 may receive (804) an indication of an event or a packet discard indication transmitted (802) from the network device 120. The event may be a congestion occurring in the communication environment 100 or any other event which requires discarding of packets. In some embodiments, the terminal device 110 may detect (806) that the event occurs.

In response to the detection of the event or the packer discard indication, the terminal device 110 may discard (808) a first duplicated packet generated by PDCP duplication of a first packet. The first duplicated packet may be discarded based on at least one of: an importance level of the first packet, a radio bearer associated with the first packet, or an RLC entity associated with the first duplicated packet.

For example, when congestion or other issues happen, the network device 120 may indicate the terminal device 110 to perform packet discard (e.g., importance-based discard via RRC/SDAP Control PDU/PDCP Control PDU/MCA CE) , or the terminal device 110 may determine that packet discard (e.g., importance-based discard) should be performed.

In some embodiments, the first duplicated packet may be discarded before a second duplicated packet generated by PDCP duplication of a second packet, and an importance level of the second packet is higher than the importance level of the first packet. In other words, a packet (for example, a SDU, a PDU, or a PDU set) with less importance shall be discarded first.

In some embodiments, the first packet may be associated with a primary RLC entity and the first duplicated packet is associated with an RLC entity different from the primary RLC entity and the first duplicated packet is discarded before the first packet. If PDCP duplication is activated (e.g., for DRB/RLC entity/importance) , a duplicated packet (for example, a duplicated PDU or PDU set) associated with the RLC entity other than the primary RLC entity activated for PDCP duplication shall be discarded before the packet (for example, a PDU or PDU set) associated with primary RLC entity.

In some embodiments, the terminal device 110 may receive from the network device 120 discard information indicating an order in which different duplicated packets are to be discarded. In such embodiments, the first duplicated packet is discarded further based on the discard information. For example, the network device 120 may indicate the terminal device 110 which DRB/RLC entities/importance should be discarded before others. In some embodiments, the discard information is received in e.g., RRC, SDAP Control PDU, PDCP Control PDU, or MCA CE. For example, the network device 120 may indicate the terminal device 110 which DRB/RLC entities/importance should be discarded before others via RRC, SDAP Control PDU, PDCP Control PDU, or MCA CE.

In general, in accordance with some embodiments of the present disclosure, if congestion or other issues happen, duplicated packets with a higher priority may be discarded. If congestion or other issues happen, PDCP duplication for a lower importance may be deactivated. Therefore, duplicated packets may be discarded first when congestion happens.

FIG. 9 illustrates a flowchart of a communication method 900 implemented a terminal device in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 900 will be described from the perspective of a terminal device, for example, the terminal device 110.

At block 910, the terminal device receives, from a network device, a duplication information indicating an activation state of Packet Data Convergence Protocol (PDCP) duplication for a plurality of importance levels, the duplication information further indicating a Quality of Service (QoS) flow with which the plurality of importance levels is associated.

At block 920, the terminal device determines, at least based on the duplication information, whether the PDCP duplication is activated for a first importance level of the plurality of importance levels.

At block 930, the terminal device in accordance with a determination that the PDCP duplication is activated for the first importance level, duplicate s, by a PDCP entity of the terminal device, a first packet within the QoS flow for submitting to a plurality of radio link control (RLC) entities of the terminal device, the first packet having the first importance level.

In some example embodiments, the terminal device may determine whether the duplication information indicate an activation of the PDCP duplication for the first importance level; determine whether the PDCP duplication is activated for a radio bearer associated with the QoS flow; and in accordance with a determination that the duplication information indicates the activation of the PDCP duplication for the first importance level and/or that the PDCP duplication is activated for the radio bearer, determine that the PDCP duplication is activated for the first importance level.

In some example embodiments, in accordance with a determination that the PDCP duplication is deactivated for the first importance level, the terminal device may indicate a secondary RLC entity of the plurality of RLC entities, by the PDCP entity, to discard a duplicated packet corresponding to the first packet.

In some example embodiments, the terminal device may determine, at least based on the duplication information, whether the PDCP duplication is deactivated for a second importance level of the plurality of importance levels; and in accordance with a determination that the PDCP duplication is deactivated for the second importance level, submit, by the PDCP entity, a second packet within the QoS flow to a primary RLC entity without duplication of the second packet, the second packet having the second importance level.

In some example embodiments, the terminal device may transmit, to the network device, assistance information comprising at least one of: the number of the plurality of importance levels, or a suggestion on one or more importance levels for which the PDCP duplication is activated.

In some example embodiments, the duplication information comprises at least one of: a plurality of fields corresponding to the plurality of importance levels, wherein a field of the plurality of fields indicates the activation state for the corresponding importance level, or an indication of a reference level for partitioning the plurality of importance levels according to whether the PDCP duplication is activated.

In some example embodiments, the duplication information may be received in at least one of: a radio resource control (RRC) message, a media access control (MAC) control element (CE) , a PDCP Control Protocol Data Unit (PDU) , or a Service Data Adaptation Protocol (SDAP) Control PDU.

In some example embodiments, the MAC CE may further comprise an identification of a radio bearer associated with the QoS flow.

In some example embodiments, the PDCP Control PDU may further comprise a type indication that the PDCP Control PDU is used for the PDCP duplication.

In some example embodiments, the SDAP Control PDU may further comprise a type indication that the PDCP Control PDU is used for the PDCP duplication.

In some example embodiments, for each importance level of the plurality of importance levels, the duplication information may further indicate whether the PDCP duplication is activated for each secondary RLC entity, and the plurality of RLC entity comprises a primary RLC entity and at least one RLC entity for which the PDCP duplication for the first importance level is activated.

In some example embodiments, the plurality of RLC entities may comprise a primary RLC entity and at least a first RLC entity other than the primary RLC entity, and the terminal device performs at least one of: indicating, by the PDCP entity to a first media access control (MAC) entity, a first PDCP data volume corresponding to the first importance level, wherein the first MAC entity is associated with the first RLC entity, and the first PDCP data volume excludes a data volume of a control packet, or indicating, by the PDCP entity to a second MAC entity, a second PDCP data volume corresponding to the first importance level as a predetermine value, wherein the second MAC entity is associated with a second RLC entity deactivated for the PDCP duplication.

In some example embodiments, the PDCP duplication may be deactivated for the second importance level, and the terminal device may perform at least one of: indicating, by the PDCP entity to a third MAC entity, a third PDCP data volume corresponding to the second importance level as a predetermine value, wherein the third MAC entity is associated with a third RLC entity other than the primary RLC entity, or indicating, by the PDCP entity to a fourth MAC entity, a fourth PDCP data volume corresponding to the second importance level as the predetermine value, wherein the fourth MAC entity is associated with a fourth RLC entity deactivated for the PDCP duplication.

FIG. 10 illustrates a flowchart of a communication method 1000 implemented at a network device in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 1000 will be described from the perspective of a network device, for example, the network device 120 in FIG. 1.

At block 1010, the network device transmits, to a terminal device, a duplication information indicating an activation state of Packet Data Convergence Protocol (PDCP) duplication for a plurality of importance levels, the duplication information further indicating a Quality of Service (QoS) flow with which the plurality of importance levels is associated.

In some example embodiments, the network device may receive, from the terminal device, assistance information comprising at least one of: the number of the plurality of importance levels, or a suggestion on one or more importance levels for which the PDCP duplication is activated.

In some example embodiments, the duplication information may comprise at least one of: a plurality of fields corresponding to the plurality of importance levels, wherein a field of the plurality of fields indicates the activation state for the corresponding importance level, or an indication of a reference level for partitioning the plurality of importance levels according to whether the PDCP duplication is activated.

In some example embodiments, for each importance level of the plurality of importance levels, the duplication information may further indicate whether the PDCP duplication is activated for each secondary RLC entity.

FIG. 11 illustrates a flowchart of a communication method 1100 implemented at a terminal device in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 1100 will be described from the perspective of a terminal device, for example, the terminal device 110 in FIG. 1.

At block 1110, in response to an event or a packet discard indication from a network device, the terminal device discards a first duplicated packet generated by Packet Data Convergence Protocol (PDCP) duplication of a first packet based on at least one of: an importance level of the first packet, a radio bearer associated with the first packet, or a radio link control (RLC) entity associated with the first duplicated packet.

In some example embodiments, the first duplicated packet may be discarded before a second duplicated packet generated by PDCP duplication of a second packet, and an importance level of the second packet is higher than the importance level of the first packet.

In some example embodiments, the first packet may be associated with a primary RLC entity and the first duplicated packet is associated with an RLC entity different from the primary RLC entity and the first duplicated packet is discarded before the first packet.

In some example embodiments, the terminal device may receive, from the network device, a discard information indicating an order in which different duplicated packets are to be discarded, and wherein the first duplicated packet is discarded further based on the discard information.

In some example embodiments, the discard information may be received in at least one of: a radio resource control (RRC) message, a media access control (MAC) control element (CE) , a PDCP Control Protocol Data Unit (PDU) , or a Service Data Adaptation Protocol (SDAP) Control PDU.

FIG. 12 illustrates a flowchart of a communication method 1200 implemented at a network device in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 1200 will be described from the perspective of a network device, for example, the network device 120 in FIG. 1.

At block 1210, the network device transmits, to a terminal device, at least one of: a packet discard indication to discard at least one duplicated packet generated by Packet Data Convergence Protocol (PDCP) duplication of a packet, or a discard information indicating an order in which different duplicated packets are to be discarded.

In some example embodiments, the discard information may be transmitted in at least one of: a radio resource control (RRC) message, a media access control (MAC) control element (CE) , a PDCP Control Protocol Data Unit (PDU) , or a Service Data Adaptation Protocol (SDAP) Control PDU.

FIG. 13 is a simplified block diagram of a device 1300 that is suitable for implementing embodiments of the present disclosure. The device 1300 can be considered as a further example implementation of any of the devices as shown in FIG. 1. Accordingly, the device 1300 can be implemented at or as at least a part of the terminal device 110 or the network device 120.

As shown, the device 1300 includes a processor 1310, a memory 1320 coupled to the processor 1310, a suitable transceiver 1340 coupled to the processor 1310, and a communication interface coupled to the transceiver 1340. The memory 1310 stores at least a part of a program 1330. The transceiver 1340 may be for bidirectional communications or a unidirectional communication based on requirements. The transceiver 1340 may include at least one of a transmitter 1342 and a receiver 1344. The transmitter 1342 and the receiver 1344 may be functional modules or physical entities. The transceiver 1340 has at least one antenna to facilitate communication, though in practice an Access Node mentioned in this application may have several ones. The communication interface may represent any interface that is necessary for communication with other network elements, such as X2/Xn interface for bidirectional communications between eNBs/gNBs, S1/NG interface for communication between a Mobility Management Entity (MME) /Access and Mobility Management Function (AMF) /SGW/UPF and the eNB/gNB, Un interface for communication between the eNB/gNB and a relay node (RN) , or Uu interface for communication between the eNB/gNB and a terminal device.

The program 1330 is assumed to include program instructions that, when executed by the associated processor 1310, enable the device 1300 to operate in accordance with the embodiments of the present disclosure, as discussed herein with reference to FIGS. 1 to 12. The embodiments herein may be implemented by computer software executable by the processor 1310 of the device 1300, or by hardware, or by a combination of software and hardware. The processor 1310 may be configured to implement various embodiments of the present disclosure. Furthermore, a combination of the processor 1310 and memory 1320 may form processing means 1350 adapted to implement various embodiments of the present disclosure.

The memory 1320 may be of any type suitable to the local technical network and may be implemented using any suitable data storage technology, such as a non-transitory computer readable storage medium, semiconductor based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory, as non-limiting examples. While only one memory 1320 is shown in the device 1300, there may be several physically distinct memory modules in the device 1300. The processor 1310 may be of any type suitable to the local technical network, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 1300 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

According to embodiments of the present disclosure, a terminal device comprising a circuitry is provided. The circuitry is configured to: receive, from a network device, a duplication information indicating an activation state of Packet Data Convergence Protocol (PDCP) duplication for a plurality of importance levels, the duplication information further indicating a Quality of Service (QoS) flow with which the plurality of importance levels is associated; determine, at least based on the duplication information, whether the PDCP duplication is activated for a first importance level of the plurality of importance levels; and in accordance with a determination that the PDCP duplication is activated for the first importance level, duplicate, by a PDCP entity of the terminal device, a first packet within the QoS flow for submitting to a plurality of radio link control (RLC) entities of the terminal device, the first packet having the first importance level. According to embodiments of the present disclosure, the circuitry may be configured to perform any method implemented by the terminal device as discussed above.

According to embodiments of the present disclosure, a network device comprising a circuitry is provided. The circuitry is configured to: transmit, to a terminal device, a duplication information indicating an activation state of Packet Data Convergence Protocol (PDCP) duplication for a plurality of importance levels, the duplication information further indicating a Quality of Service (QoS) flow with which the plurality of importance levels is associated. According to embodiments of the present disclosure, the circuitry may be configured to perform any method implemented by the network device as discussed above.

According to embodiments of the present disclosure, a terminal device comprising a circuitry is provided. The circuitry is configured to: in response to an event or a packet discard indication from a network device, discard a first duplicated packet generated by Packet Data Convergence Protocol (PDCP) duplication of a first packet based on at least one of: an importance level of the first packet, a radio bearer associated with the first packet, or a radio link control (RLC) entity associated with the first duplicated packet. According to embodiments of the present disclosure, the circuitry may be configured to perform any method implemented by the terminal device as discussed above.

According to embodiments of the present disclosure, a network device comprising a circuitry is provided. The circuitry is configured to: a packet discard indication to discard at least one duplicated packet generated by Packet Data Convergence Protocol (PDCP) duplication of a packet, or a discard information indicating an order in which different duplicated packets are to be discarded. According to embodiments of the present disclosure, the circuitry may be configured to perform any method implemented by the network device as discussed above.

The term “circuitry” used herein may refer to hardware circuits and/or combinations of hardware circuits and software. For example, the circuitry may be a combination of analog and/or digital hardware circuits with software/firmware. As a further example, the circuitry may be any portions of hardware processors with software including digital signal processor (s) , software, and memory (ies) that work together to cause an apparatus, such as a terminal device or a network device, to perform various functions. In a still further example, the circuitry may be hardware circuits and or processors, such as a microprocessor or a portion of a microprocessor, that requires software/firmware for operation, but the software may not be present when it is not needed for operation. As used herein, the term circuitry also covers an implementation of merely a hardware circuit or processor (s) or a portion of a hardware circuit or processor (s) and its (or their) accompanying software and/or firmware.

In summary, embodiments of the present disclosure provide the following aspects.

In an aspect, it is proposed a terminal device comprising: a processor configured to cause the terminal device to: receive, from a network device, a duplication information indicating an activation state of Packet Data Convergence Protocol (PDCP) duplication for a plurality of importance levels, the duplication information further indicating a Quality of Service (QoS) flow with which the plurality of importance levels is associated; determine, at least based on the duplication information, whether the PDCP duplication is activated for a first importance level of the plurality of importance levels; and in accordance with a determination that the PDCP duplication is activated for the first importance level, duplicate, by a PDCP entity of the terminal device, a first packet within the QoS flow for submitting to a plurality of radio link control (RLC) entities of the terminal device, the first packet having the first importance level.

In some embodiments, the terminal device is further caused to: determine whether the duplication information indicate an activation of the PDCP duplication for the first importance level; determine whether the PDCP duplication is activated for a radio bearer associated with the QoS flow; and in accordance with a determination that the duplication information indicates the activation of the PDCP duplication for the first importance level and/or that the PDCP duplication is activated for the radio bearer, determine that the PDCP duplication is activated for the first importance level.

In some embodiments, the terminal device is further caused to: in accordance with a determination that the PDCP duplication is deactivated for the first importance level, indicate a secondary RLC entity of the plurality of RLC entities, by the PDCP entity, to discard a duplicated packet corresponding to the first packet.

In some embodiments, the terminal device is further caused to: determine, at least based on the duplication information, whether the PDCP duplication is deactivated for a second importance level of the plurality of importance levels; and in accordance with a determination that the PDCP duplication is deactivated for the second importance level, submit, by the PDCP entity, a second packet within the QoS flow to a primary RLC entity without duplication of the second packet, the second packet having the second importance level.

In some embodiments, the terminal device is further caused to: transmit, to the network device, assistance information comprising at least one of: the number of the plurality of importance levels, or a suggestion on one or more importance levels for which the PDCP duplication is activated.

In some embodiments, the duplication information comprises at least one of: a plurality of fields corresponding to the plurality of importance levels, wherein a field of the plurality of fields indicates the activation state for the corresponding importance level, or an indication of a reference level for partitioning the plurality of importance levels according to whether the PDCP duplication is activated.

In some embodiments, the duplication information is received in at least one of: a radio resource control (RRC) message, a media access control (MAC) control element (CE) , a PDCP Control Protocol Data Unit (PDU) , or a Service Data Adaptation Protocol (SDAP) Control PDU.

In some embodiments, the MAC CE further comprises an identification of a radio bearer associated with the QoS flow.

In some embodiments, the PDCP Control PDU further comprises a type indication that the PDCP Control PDU is used for the PDCP duplication.

In some embodiments, the SDAP Control PDU further comprises a type indication that the PDCP Control PDU is used for the PDCP duplication.

In some embodiments, for each importance level of the plurality of importance levels, the duplication information further indicates whether the PDCP duplication is activated for each secondary RLC entity, and the plurality of RLC entity comprises a primary RLC entity and at least one RLC entity for which the PDCP duplication for the first importance level is activated.

In some embodiments, the plurality of RLC entities comprises a primary RLC entity and at least a first RLC entity other than the primary RLC entity, and the terminal device is further caused to perform at least one of: indicating, by the PDCP entity to a first media access control (MAC) entity, a first PDCP data volume corresponding to the first importance level, wherein the first MAC entity is associated with the first RLC entity, and the first PDCP data volume excludes a data volume of a control packet, or indicating, by the PDCP entity to a second MAC entity, a second PDCP data volume corresponding to the first importance level as a predetermine value, wherein the second MAC entity is associated with a second RLC entity deactivated for the PDCP duplication.

In some embodiments, the PDCP duplication is deactivated for the second importance level, and the terminal device is further caused to perform at least one of: indicating, by the PDCP entity to a third MAC entity, a third PDCP data volume corresponding to the second importance level as a predetermine value, wherein the third MAC entity is associated with a third RLC entity other than the primary RLC entity, or indicating, by the PDCP entity to a fourth MAC entity, a fourth PDCP data volume corresponding to the second importance level as the predetermine value, wherein the fourth MAC entity is associated with a fourth RLC entity deactivated for the PDCP duplication.

In an aspect, it is proposed a network device. The network device comprises: a processor configured to cause the network device to: transmit, to a terminal device, a duplication information indicating an activation state of Packet Data Convergence Protocol (PDCP) duplication for a plurality of importance levels, the duplication information further indicating a Quality of Service (QoS) flow with which the plurality of importance levels is associated.

In some embodiments, the network device is further caused to: receive, from the terminal device, assistance information comprising at least one of: the number of the plurality of importance levels, or a suggestion on one or more importance levels for which the PDCP duplication is activated.

In some embodiments, for each importance level of the plurality of importance levels, the duplication information further indicates whether the PDCP duplication is activated for each secondary RLC entity.

In an aspect, it is proposed a terminal device. The terminal device comprises: a processor configured to cause the terminal device to: in response to an event or a packet discard indication from a network device, discard a first duplicated packet generated by Packet Data Convergence Protocol (PDCP) duplication of a first packet based on at least one of: an importance level of the first packet, a radio bearer associated with the first packet, or a radio link control (RLC) entity associated with the first duplicated packet.

In some embodiments, the first duplicated packet is discarded before a second duplicated packet generated by PDCP duplication of a second packet, and an importance level of the second packet is higher than the importance level of the first packet.

In some embodiments, the first packet is associated with a primary RLC entity and the first duplicated packet is associated with an RLC entity different from the primary RLC entity and the first duplicated packet is discarded before the first packet.

In some embodiments, the terminal device is further caused to: receive, from the network device, a discard information indicating an order in which different duplicated packets are to be discarded, and wherein the first duplicated packet is discarded further based on the discard information.

In some embodiments, the discard information is received in at least one of: a radio resource control (RRC) message, a media access control (MAC) control element (CE) , a PDCP Control Protocol Data Unit (PDU) , or a Service Data Adaptation Protocol (SDAP) Control PDU.

In an aspect, it is proposed a network device. The network device comprises: a processor configured to cause the network device to transmit, to a terminal device, at least one of: a packet discard indication to discard at least one duplicated packet generated by Packet Data Convergence Protocol (PDCP) duplication of a packet, or a discard information indicating an order in which different duplicated packets are to be discarded.

In some embodiments, the discard information is transmitted in at least one of: a radio resource control (RRC) message, a media access control (MAC) control element (CE) , a PDCP Control Protocol Data Unit (PDU) , or a Service Data Adaptation Protocol (SDAP) Control PDU.

In an aspect, a terminal device comprises at least one processor; and at least one memory coupled to the at least one processor and storing instructions thereon, the instructions, when executed by the at least one processor, causing the device to perform the method implemented by the terminal device discussed above.

In an aspect, a network device comprises at least one processor; and at least one memory coupled to the at least one processor and storing instructions thereon, the instructions, when executed by the at least one processor, causing the device to perform the method implemented by the network device discussed above.

In an aspect, it is provided a computer readable medium having instructions stored thereon, the instructions, when executed on at least one processor, causing the at least one processor to perform the method implemented by the terminal device discussed above.

In an aspect, it is provided a computer readable medium having instructions stored thereon, the instructions, when executed on at least one processor, causing the at least one processor to perform the method implemented by the network device discussed above.

In an aspect, it is provided a computer program comprising instructions, the instructions, when executed on at least one processor, causing the at least one processor to perform the method implemented by the terminal device discussed above.

In an aspect, it is provided a computer program comprising instructions, the instructions, when executed on at least one processor, causing the at least one processor to perform the method implemented by the network device discussed above.

Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representation, it will be appreciated that the blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, being executed in a device on a target real or virtual processor, to carry out the process or method as described above with reference to FIGS. 1 to 13. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the processor or controller, cause the functions/operations specified in the flowcharts and/or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

The above program code may be embodied on a machine readable medium, which may be any tangible medium that may contain, or store a program for use by or in connection 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. A machine readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the machine readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM) , a read-only memory (ROM) , an erasable programmable read-only memory (EPROM or Flash memory) , an optical fiber, a portable compact disc read-only memory (CD-ROM) , an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable sub-combination.

Although the present disclosure has been described in language specific to structural features and/or methodological acts, it is to be understood that the present disclosure 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

A terminal device comprising:

a processor configured to cause the terminal device to:

receive, from a network device, a duplication information indicating an activation state of Packet Data Convergence Protocol (PDCP) duplication for a plurality of importance levels, the duplication information further indicating a Quality of Service (QoS) flow with which the plurality of importance levels is associated;

determine, at least based on the duplication information, whether the PDCP duplication is activated for a first importance level of the plurality of importance levels; and

in accordance with a determination that the PDCP duplication is activated for the first importance level, duplicate, by a PDCP entity of the terminal device, a first packet within the QoS flow for submitting to a plurality of radio link control (RLC) entities of the terminal device, the first packet having the first importance level.
The terminal device of claim 1, wherein the terminal device is further caused to:

determine whether the duplication information indicate an activation of the PDCP duplication for the first importance level;

determine whether the PDCP duplication is activated for a radio bearer associated with the QoS flow; and

in accordance with a determination that the duplication information indicates the activation of the PDCP duplication for the first importance level and/or that the PDCP duplication is activated for the radio bearer, determine that the PDCP duplication is activated for the first importance level.
The terminal device of claim 1, wherein the terminal device is further caused to:

in accordance with a determination that the PDCP duplication is deactivated for the first importance level, indicate a secondary RLC entity of the plurality of RLC entities, by the PDCP entity, to discard a duplicated packet corresponding to the first packet.
The terminal device of claim 1, wherein the terminal device is further caused to:

determine, at least based on the duplication information, whether the PDCP duplication is deactivated for a second importance level of the plurality of importance levels; and

in accordance with a determination that the PDCP duplication is deactivated for the second importance level, submit, by the PDCP entity, a second packet within the QoS flow to a primary RLC entity without duplication of the second packet, the second packet having the second importance level.
The terminal device of claim 1, wherein the terminal device is further caused to:

transmit, to the network device, assistance information comprising at least one of:

the number of the plurality of importance levels, or

a suggestion on one or more importance levels for which the PDCP duplication is activated.
The terminal device of claim 1, wherein the duplication information comprises at least one of:

a plurality of fields corresponding to the plurality of importance levels, wherein a field of the plurality of fields indicates the activation state for the corresponding importance level, or

an indication of a reference level for partitioning the plurality of importance levels according to whether the PDCP duplication is activated.
The terminal device of claim 6, wherein the duplication information is received in at least one of:

a radio resource control (RRC) message,

a media access control (MAC) control element (CE) ,

a PDCP Control Protocol Data Unit (PDU) , or

a Service Data Adaptation Protocol (SDAP) Control PDU.
The terminal device of claim 7, wherein the MAC CE further comprises an identification of a radio bearer associated with the QoS flow,

the PDCP Control PDU further comprises a type indication that the PDCP Control PDU is used for the PDCP duplication, or

the SDAP Control PDU further comprises a type indication that the PDCP Control PDU is used for the PDCP duplication.
The terminal device of claim 1, wherein for each importance level of the plurality of importance levels, the duplication information further indicates whether the PDCP duplication is activated for each secondary RLC entity, and

the plurality of RLC entity comprises a primary RLC entity and at least one RLC entity for which the PDCP duplication for the first importance level is activated.
The terminal device of claim 1, wherein the plurality of RLC entities comprises a primary RLC entity and at least a first RLC entity other than the primary RLC entity, and the terminal device is further caused to perform at least one of:

indicating, by the PDCP entity to a first media access control (MAC) entity, a first PDCP data volume corresponding to the first importance level, wherein the first MAC entity is associated with the first RLC entity, and the first PDCP data volume excludes a data volume of a control packet, or

indicating, by the PDCP entity to a second MAC entity, a second PDCP data volume corresponding to the first importance level as a predetermine value, wherein the second MAC entity is associated with a second RLC entity deactivated for the PDCP duplication.
The terminal device of claim 4, wherein the PDCP duplication is deactivated for the second importance level, and the terminal device is further caused to perform at least one of:

indicating, by the PDCP entity to a third MAC entity, a third PDCP data volume corresponding to the second importance level as a predetermine value, wherein the third MAC entity is associated with a third RLC entity other than the primary RLC entity, or

indicating, by the PDCP entity to a fourth MAC entity, a fourth PDCP data volume corresponding to the second importance level as the predetermine value, wherein the fourth MAC entity is associated with a fourth RLC entity deactivated for the PDCP duplication.
A network device comprising:

a processor configured to cause the network device to:

transmit, to a terminal device, a duplication information indicating an activation state of Packet Data Convergence Protocol (PDCP) duplication for a plurality of importance levels, the duplication information further indicating a Quality of Service (QoS) flow with which the plurality of importance levels is associated.
The network device of claim 12, wherein the duplication information comprises at least one of:

a plurality of fields corresponding to the plurality of importance levels, wherein a field of the plurality of fields indicates the activation state for the corresponding importance level, or

an indication of a reference level for partitioning the plurality of importance levels according to whether the PDCP duplication is activated.
A terminal device comprising:

a processor configured to cause the terminal device to:

in response to an event or a packet discard indication from a network device, discard a first duplicated packet generated by Packet Data Convergence Protocol (PDCP) duplication of a first packet based on at least one of:

an importance level of the first packet,

a radio bearer associated with the first packet, or

a radio link control (RLC) entity associated with the first duplicated packet.
The terminal device of claim 14, wherein the first duplicated packet is discarded before a second duplicated packet generated by PDCP duplication of a second packet, and an importance level of the second packet is higher than the importance level of the first packet, and/or

wherein the first packet is associated with a primary RLC entity and the first duplicated packet is associated with an RLC entity different from the primary RLC entity and the first duplicated packet is discarded before the first packet.
The terminal device of claim 14, wherein the terminal device is further caused to:

receive, from the network device, discard information indicating an order in which different duplicated packets are to be discarded, and

wherein the first duplicated packet is discarded further based on the discard information.
A network device comprising:

a processor configured to cause the network device to transmit, to a terminal device, at least one of:

a packet discard indication to discard at least one duplicated packet generated by Packet Data Convergence Protocol (PDCP) duplication of a packet, or

a discard information indicating an order in which different duplicated packets are to be discarded.
A communication method implemented at a terminal device, comprising:

receiving, from a network device, a duplication information indicating an activation state of Packet Data Convergence Protocol (PDCP) duplication for a plurality of importance levels, the duplication information further indicating a Quality of Service (QoS) flow with which the plurality of importance levels is associated;

determining, at least based on the duplication information, whether the PDCP duplication is activated for a first importance level of the plurality of importance levels; and

in accordance with a determination that the PDCP duplication is activated for the first importance level, duplicating, by a PDCP entity of the terminal device, a first packet within the QoS flow for submitting to a plurality of radio link control (RLC) entities of the terminal device, the first packet having the first importance level.
A communication method implemented at a network device, comprising:

transmitting, to a terminal device, a duplication information indicating an activation state of Packet Data Convergence Protocol (PDCP) duplication for a plurality of importance levels, the duplication information further indicating a Quality of Service (QoS) flow with which the plurality of importance levels is associated.
A communication method implemented at a terminal device, comprising:

in response to an event or a packet discard indication from a network device, discarding a first duplicated packet generated by Packet Data Convergence Protocol (PDCP) duplication of a first packet based on at least one of:

an importance level of the first packet,

a radio bearer associated with the first packet, or

a radio link control (RLC) entity associated with the first duplicated packet.