WO2025200026A1

WO2025200026A1 - Pdcp duplication

Info

Publication number: WO2025200026A1
Application number: PCT/CN2024/085067
Authority: WO
Inventors: Benoist Pierre Sebire; Chunli Wu; Sunyoung Lee
Original assignee: Nokia Shanghai Bell Co Ltd; Nokia Solutions and Networks Oy; Nokia Technologies Oy
Current assignee: Nokia Shanghai Bell Co Ltd; Nokia Solutions and Networks Oy; Nokia Technologies Oy
Priority date: 2024-03-29
Filing date: 2024-03-29
Publication date: 2025-10-02
Anticipated expiration: 2026-09-29

Abstract

Embodiments of the present disclosure relate to packet data convergence protocol (PDCP) duplication. In an aspect, a terminal device determines a change of a priority level of a logical channel (LCH) of a radio bearer (RB). If the priority level increases, the terminal device activates PDCP duplication for the RB. If the priority level decreases, the terminal device deactivates PDCP duplication for the RB.

Description

PDCP DUPLICATION

FIELD

Various example embodiments relate to the field of communications and in particular, to devices, methods, apparatuses, and computer readable storage media for packet data convergence protocol (PDCP) duplication.

BACKGROUND

In communication technology, there is a constant evolution ongoing in order to provide efficient and reliable solutions for utilizing wireless communication networks. Each new generation has its own technical challenges for handling different situations and processes that are needed to connect and serve devices connected to wireless networks. To meet the demand for increased wireless data traffic since the deployment of 4th generation (4G) communication systems, efforts have been made to develop an improved 5th generation (5G) , pre-5G, 5G-advanced communication system, or a 6th generation (6G) system. The new communication systems can support various types of service applications for terminal devices.

PDCP duplication (also referred to as PDCP packet duplication) is introduced as a means to increase reliability and reduce latency. With PDCP duplication, one or more secondary RLC entities (i.e. one or more secondary legs) may be used to transmit duplicates. However, there are still some open problems in the PDCP duplication that will be studied in the near future.

SUMMARY

In general, example embodiments of the present disclosure provide a solution related to PDCP duplication.

In a first aspect, there is provided a terminal device. The terminal device comprises at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the terminal device at least to: determine a change of a priority level of a logical channel (LCH) of a radio bearer (RB) ; and one of the following: based on determining that the priority level increases or a priority value of the LCH decreases, activate packet data convergence protocol (PDCP) duplication for the RB; or based on determining that the priority level decreases or a priority value of the LCH increases, deactivate PDCP duplication for the RB.

In a second aspect, there is provided a network device. The network device comprises at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the network device at least to: determine one or more thresholds of a priority level of a logical channel (LCH) of a radio bearer (RB) , the one or more thresholds being used for a terminal device to activate or deactivate packet data convergence protocol (PDCP) duplication for the RB; and transmit the one or more thresholds to the terminal device.

In a third aspect, there is provided a method. The method comprises determining, at a terminal device, a change of a priority level of a logical channel (LCH) of a radio bearer (RB) ; and one of the following: based on determining that the priority level increases or a priority value of the LCH decreases, activating, at the terminal device, packet data convergence protocol (PDCP) duplication for the RB; or based on determining that the priority level decreases or a priority value of the LCH increases, deactivating, at the terminal device, PDCP duplication for the RB.

In a fourth aspect, there is provided a method. The method comprises determining, at a network device, one or more thresholds of a priority level of a logical channel (LCH) of a radio bearer (RB) , the one or more thresholds being used for a terminal device to activate or deactivate packet data convergence protocol (PDCP) duplication for the RB; and transmitting, at the network device, the one or more thresholds to the terminal device.

In a fifth aspect, there is provided an apparatus. The apparatus comprises means for determining, at a terminal device, a change of a priority level of a logical channel (LCH) of a radio bearer (RB) ; and one of the following: means for, based on determining that the priority level increases or a priority value of the LCH decreases, activating, at the terminal device, packet data convergence protocol (PDCP) duplication for the RB; or means for, based on determining that the priority level decreases or a priority value of the LCH increases, deactivating, at the terminal device, PDCP duplication for the RB.

In a sixth aspect, there is provided an apparatus. The apparatus comprises means for determining, at a network device, one or more thresholds of a priority level of a logical channel (LCH) of a radio bearer (RB) , the one or more thresholds being used for a terminal device to activate or deactivate packet data convergence protocol (PDCP) duplication for the RB;and means for transmitting, at the network device, the one or more thresholds to the terminal device.

In a seventh aspect, there is provided a non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the method according to any one of the above third and fourth aspects.

In an eighth aspect, there is provided a computer program comprising instructions, which, when executed by an apparatus, cause the apparatus at least to perform at least the method according to any one of the above third and fourth aspects.

In a ninth aspect, there is provided a terminal device. The terminal device comprises determining circuitry configured to determine a change of a priority level of a logical channel (LCH) of a radio bearer (RB) ; and one of the following: activating circuitry configured to, based on determining that the priority level increases or a priority value of the LCH decreases, activate packet data convergence protocol (PDCP) duplication for the RB; or deactivating circuitry configured to, based on determining that the priority level decreases or a priority value of the LCH increases, deactivate PDCP duplication for the RB.

In a tenth aspect, there is provided a network device. The network device comprises determining circuitry configured to determine one or more thresholds of a priority level of a logical channel (LCH) of a radio bearer (RB) , the one or more thresholds being used for a terminal device to activate or deactivate packet data convergence protocol (PDCP) duplication for the RB; and transmitting circuitry configured to transmit the one or more thresholds to the terminal device.

It is to be understood that the summary section is not intended to identify key or essential features of embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become easily comprehensible through the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

Some example embodiments will now be described with reference to the accompanying drawings, in which:

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

FIG. 1B illustrates a schematic diagram of PDCP duplication associated with some embodiments of the present disclosure;

FIG. 2 illustrates a signaling flow between a terminal device and a network device according to some example embodiments of the present disclosure;

FIG. 3 illustrates a flowchart of a method implemented at a terminal device according to some embodiments of the present disclosure;

FIG. 4 illustrates a flowchart of a method implemented at a network device according to some embodiments of the present disclosure;

FIG. 5 illustrates a simplified block diagram of a device that is suitable for implementing some example embodiments of the present disclosure; and

FIG. 6 illustrates a block diagram of an example of a computer readable medium in accordance with some 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 for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. The disclosure described herein 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.

References in the present disclosure to “one embodiment, ” “an embodiment, ” “an example embodiment, ” and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

It shall be understood that although the terms “first” and “second” etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and/or” includes any and all combinations of one or more of the listed terms.

The terminology used herein is for the purpose of describing particular embodiments and is not intended to be limiting of example embodiments. As used herein, the singular forms “a” , “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” , “comprising” , “has” , “having” , “includes” and/or “including” , when used herein, specify the presence of stated features, elements, and/or components etc., but do not preclude the presence or addition of one or more other features, elements, components and/or combinations thereof. As used herein, “at least one of the following: <a list of two or more elements>” and “at least one of <a list of two or more elements>” and similar wording, where the list of two or more elements are joined by “and” or “or” , mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.

As used in this application, the term “circuitry” may refer to one or more or all of the following:

(a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and

(b) combinations of hardware circuits and software, such as (as applicable) :

(i) a combination of analog and/or digital hardware circuit (s) with software/firmware and

(ii) any portions of hardware processor (s) with software (including digital signal processor (s) ) , software, and memory (ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and

(c) hardware circuit (s) and or processor (s) , such as a microprocessor (s) or a portion of a microprocessor (s) , that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and/or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

As used herein, the term “communication network” refers to a network following any suitable communication standards, such as new radio (NR) , long term evolution (LTE) , LTE-advanced (LTE-A) , wideband code division multiple access (WCDMA) , high-speed packet access (HSPA) , narrow band internet of things (NB-IoT) and so on. Furthermore, the communications between a terminal device and a network device in the communication network may be performed according to any suitable generation communication protocols, including, but not limited to, the third generation (3G) , the 4G, 4.5G, 5G, or 6G communication protocols, and/or any other protocols either currently known or to be developed in the future. Embodiments of the present disclosure may be applied in various communication systems. Given the rapid development in communications, there will of course also be future type communication technologies and systems with which the present disclosure may be embodied. It should not be seen as limiting the scope of the present disclosure to only the aforementioned system.

As used herein, the term “network device” refers to a node in a communication network via which a terminal device can access the communication network and receive services therefrom. The network device may refer to a base station (BS) or an access point (AP) , for example, a node B (NodeB or NB) , a radio access network (RAN) node, an evolved NodeB (eNodeB or eNB) , an NR NB (also referred to as a gNB) , a remote radio unit (RRU) , a radio header (RH) , an infrastructure device for a V2X (vehicle-to-everything) communication, a transmission and reception point (TRP) , a reception point (RP) , a remote radio head (RRH) , a relay, an integrated access and backhaul (IAB) node, a low power node such as a femto BS, a pico BS, and so forth, depending on the applied terminology and technology.

The term “terminal device” refers to any end device that may be capable of wireless communication. By way of example rather than limitation, a terminal device may also be referred to as a communication device, user equipment (UE) , a subscriber station (SS) , a portable subscriber station, a mobile station (MS) , or an access terminal (AT) . The terminal device may include, but not limited to, a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones, a tablet, a wearable terminal device, a personal digital assistant (PDA) , portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE) , laptop-mounted equipment (LME) , USB dongles, smart devices, wireless customer-premises equipment (CPE) , an Internet of Things (IoT) device, a watch or other wearable, a head-mounted display (HMD) , a vehicle, a drone, a medical device and applications (e.g., remote surgery) , an industrial device and applications (e.g., a robot and/or other wireless devices operating in an industrial and/or an automated processing chain contexts) , a consumer electronics device, a device operating on commercial and/or industrial wireless networks, and the like. In the following description, the terms “terminal device” , “communication device” , “terminal” , “user equipment” and “UE” may be used interchangeably.

As described above, PDCP duplication was introduced in new radio (NR) release 15 (Rel-15) as a means to increase reliability and reduce latency. With PDCP duplication, a secondary radio link control (RLC) entity (i.e. a secondary leg) may be used to transmit duplicates. Moreover, more than one secondary leg was later introduced for ultra-reliable low latency communication (URLLC) in release 16 (Rel-16) .

In addition, UL scheduling enhancement to enable high extended reality (XR) capacity while meeting delay requirements or avoiding too-late protocol data units (PDUs) has been discussed. The PDCP duplication-related latency issue has been noticed. However, as of now, there is no effective way to address this issue.

Moreover, the inventors notice that logical channel priority (LCP) priority adjustment is indeed a time-critical operation. LCP has been specified in the third-generation partnership project (3GPP) technical specification (TS) 38.321. LCP enhancements were already discussed in release 18 (Rel-18) but no agreement was reached due to the increased complexity. Both UE and chipset vendors were hesitant to introduce a delay component in the loop (s) that allocates resources.

In view of the above, optimizing the PDCP duplication is still an important issue to be solved. Especially, the possible interaction between the PDCP duplication and the LCH priority adjustment may need to be investigated.

According to embodiments of the present disclosure, there is provided a scheme for PDCP duplication. With this scheme, a terminal device determines a change of a priority level of an LCH of an RB. If the priority level increases, the terminal device activates PDCP duplication for the RB. If the priority level decreases, the terminal device deactivates PDCP duplication for the RB.

By activating or deactivating PDCP duplication based on the change of the priority level of the LCH, the terminal device can transmit data to the network device in time, hence increasing the chances of having urgent data reaching the network device without extra delay and overhead. In this way, it is allowed to improve the flexibility of data reporting, and thus improve transmission efficiency.

Hereinafter, principles and embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Reference is first made to FIG. 1A, which illustrates an example environment 100 in which example embodiments of the present disclosure can be implemented.

The environment 100, which may be a part of a communication network, comprises a terminal device 110 and a network device 120 communicating with each other. The communication between the terminal device 110 and the network device 120 may be direct or indirect. As an example, the terminal device 110 and the network device 120 may communicate with one or more further devices not shown in FIG. 1A.

To transmit data and/or control information, the terminal device 110 may perform communications with the network device 120. A link from the network device 120 to the terminal device 110 is referred to as a downlink (DL) , while a link from the terminal device 110 to the network device 120 is referred to as an uplink (UL) .

Although the terminal device 110 and the network device 120 are described in the communication environment 100 of FIG. 1A, embodiments of the present disclosure may equally apply to any other suitable communication devices in communication with one another. That is, embodiments of the present disclosure are not limited to the exemplary scenarios of FIG. 1A. In this regard, it is noted that although the terminal device is schematically depicted as a mobile phone and the network device 120 is schematically depicted as a base station in FIG. 1A, it is understood that these depictions are exemplary in nature without suggesting any limitation. In other embodiments, the first device 110 and the network device 120 may be any other communication devices, for example, any other wireless communication devices.

It is to be understood that the particular number of various communication devices and the particular number of various communication links as shown in FIG. 1A is for illustration purpose only without suggesting any limitations. The communication environment 100 may include any suitable number of communication devices and any suitable number of communication links for implementing embodiments of the present disclosure. In addition, it should be appreciated that there may be various wireless as well as wireline communications (if needed) among all of the communication devices.

The communications in the environment 100 may follow any suitable communication standards or protocols, which are already in existence or to be developed in the future, such as Universal Mobile Telecommunications System (UMTS) , long term evolution (LTE) , LTE-Advanced (LTE-A) , the fifth generation (5G) New Radio (NR) , 6G, Wireless Fidelity (Wi-Fi) and Worldwide Interoperability for Microwave Access (WiMAX) standards, and employs any suitable communication technologies, including, for example, Multiple-Input Multiple-Output (MIMO) , Orthogonal Frequency Division Multiplexing (OFDM) , time division multiplexing (TDM) , frequency division multiplexing (FDM) , code division multiplexing (CDM) , Bluetooth, ZigBee, and machine type communication (MTC) , enhanced mobile broadband (eMBB) , massive machine type communication (mMTC) , ultra-reliable low latency communication (URLLC) , Carrier Aggregation (CA) , Dual Connectivity (DC) , and New Radio Unlicensed (NR-U) technologies.

FIG. 1B illustrates a schematic diagram of PDCP duplication associated with some embodiments of the present disclosure. As shown in FIG. 1B, a primary RLC entity and a secondary RLC entity may be used for data transmission. The secondary RLC entity may be used to transmit data duplicates.

FIG. 2 illustrates a signaling flow 200 between a terminal device and a network device according to some example embodiments of the present disclosure. For the purpose of discussion, the signaling flow 200 will be described with reference to FIG. 1A.

As shown in FIG. 2, at 205, the terminal device 110 determines a change of a priority level of an LCH of an RB. For example, the terminal device 110 may determine a change of a priority value of the LCH, which reflects the change of the priority level of the LCH. A higher priority level may correspond to a lower priority value. For example, the RB may be configured with PDCP duplication. As an example, the LCH may comprise a primary LCH of the RB. In this case, the PDCP duplication may be associated with the priority level change of the primary LCH. Alternatively or additionally, the LCH may comprise a secondary LCH, for example, a specific secondary LCH or a selected secondary LCH. Hereinafter, taking the change of the priority of the primary LCH as an example to discuss some embodiments for PDCP duplication, it should be appreciated that similar steps or features can be equally or similarly applicable to the change of the priority of the secondary LCH.

In some example embodiments, the terminal device 110 may determine the change of the priority level of the primary LCH in a variety of approaches. As an example, the terminal device 110 may receive an indication indicating the change of the priority level of the primary LCH from the network device 120, and then on this basis, the terminal device 110 may determine that the priority level of the primary LCH may be changed. As another example, the change of the priority level of the primary LCH may be determined by the terminal device 110 itself, without an indication associated with the change from the network device 120. As an example implementation, the terminal device 110 may determine that the priority level of the primary LCH may need to be changed based on a delay criterion associated with buffered data. For example, if the remaining time for the buffered data is less than (or equal to) a first time threshold, the terminal device 110 may determine to increase the priority level of the primary LCH. If the remaining time for the buffered data exceeds a second time threshold, the terminal device 110 may determine to decrease the priority level of the primary LCH. The above time threshold (s) may be pre-defined or configured by the network device 120. As another example implementation, the terminal device 110 may determine that the priority level of the primary LCH may need to be changed based on the amount of the buffered data. For example, the terminal device 110 may increase the priority level of the primary LCH if the amount of the buffered data is above a first data threshold, and decrease the priority level of the primary LCH if the amount of the buffered data is below a second data threshold. The above data threshold (s) may be pre-defined or configured by the network device 120.

Then, as shown in FIG. 2, at 210, the terminal device 110 activates PDCP duplication for the RB if the priority level of the primary LCH increases, or deactivates PDCP duplication for the RB if the priority level of the primary LCH decreases. In other words, the terminal device 110 may activate PDCP duplication for the RB if the priority value of the primary LCH decreases, or deactivate PDCP duplication for the RB if the priority value of the primary LCH increases. It is to be understood that hereinafter, taking the expressions that the priority level of the primary LCH increases or decreases as an example to discuss some embodiments, it should be appreciated that similar steps or features can be equally or similarly applicable to the expressions that the priority value of the primary LCH decreases or increases respectively. The activation or the deactivation of the PDCP duplication may be performed considering one or more priority thresholds of the primary LCH.

In some example embodiments, only one priority threshold (also referred to as a first threshold) may be configured and used for activating and deactivating PDCP duplication. In some implementations, the terminal device 110 may activate PDCP duplication for the RB if the priority level of the primary LCH is higher than or equal to the first threshold, and deactivate PDCP duplication for the RB if the priority level of the primary LCH is lower than the first threshold. For example, the terminal device 110 may activate PDCP duplication on one or more secondary LCHs (for example, all secondary LCH (s) ) if the priority level of the primary LCH is higher than or equal to the first threshold, and deactivate PDCP duplication on one or more secondary LCHs (for example, all secondary LCH (s) ) if the priority level of the primary LCH is lower than the first threshold. In other words, considering that a higher priority level corresponds to a lower priority value, if the priority value of the primary LCH is higher than the priority value threshold, PDCP duplication may be deactivated, for example, on all secondary LCHs, and if the priority value of the primary LCH is lower than or equal to the priority value threshold, PDCP duplication may become active, for example, on all secondary LCHs. Alternatively or additionally, in some other implementations, the terminal device 110 may activate PDCP duplication for the RB if the priority level of the primary LCH is higher than the first threshold, and deactivate PDCP duplication for the RB if the priority level of the primary LCH is lower than or equal the first threshold. The implementation details are similar, and for the purpose of simplification, the details will be omitted.

In some example embodiments, two different priority thresholds (also referred to as a first threshold and a second threshold) may be configured and used for activating and deactivating PDCP duplication respectively. The terminal device 110 may activate PDCP duplication for the RB if the priority level of the primary LCH is not less than (or higher than) the first threshold, and deactivate PDCP duplication for the RB if the priority level of the primary LCH is lower than (or not more than) the second threshold. For example, the terminal device 110 may activate PDCP duplication on one or more secondary LCHs (for example, all secondary LCH (s) ) if the priority level of the primary LCH is not less than (or higher than) to the first threshold, and deactivate PDCP duplication on one or more secondary LCHs (for example, all secondary LCH (s) ) if the priority level of the primary LCH is lower than (or not more than) the second threshold. In other words, as an example implementation, considering that a higher priority level corresponds to a lower priority value, a first priority value threshold may be configured for PDCP duplication to become active from deactivated, and a second priority value threshold may be configured for PDCP duplication to become deactivated from active. In this case, once PDCP duplication is deactivated, as long as the priority value of the primary LCH remains not less than (or higher than) the first priority value threshold, PDCP duplication may remain deactivated, and once PDCP duplication is activated, as long as the priority value remains lower than (or not more than) the second priority value threshold, PDCP duplication may remain active.

In some example embodiments where multiple secondary LCHs are configured for the RB with PDCP duplication, a plurality priority thresholds may be configured and used for activating or deactivating PDCP duplication on different secondary LCHs respectively. For example, the terminal device 110 may activate PDCP duplication on a first number of secondary LCHs (i.e., a first set of secondary LCHs) if the priority level of the primary LCH is not less than (or higher than) to a third threshold, and activate PDCP duplication on a second number of secondary LCHs (i.e., a second set of secondary LCHs) if the priority level of the primary LCH is not less than (or higher than) a fourth threshold. The secondary LCHs may be selected to be activated based on their identities. As an example, the third threshold may be configured for PDCP duplication on the first secondary LCH, and the fourth threshold may be configured for PDCP duplication on the second secondary LCH. As a possible result, the higher the priority level increases on the primary LCH, the larger the number of secondary LCHs used for PDCP duplication. Alternatively or additionally, the terminal device 110 may deactivate PDCP duplication on a third number of secondary LCHs, if the priority level of the primary LCH is lower than (or not more than) a fifth threshold, and deactivate PDCP duplication on a fourth number of secondary LCHs if the priority level of the primary LCH is lower than (or not more than) a sixth threshold. The implementation details are similar, and for the purpose of simplification, the details will be omitted.

The above one or more priority thresholds may be configured in multiple ways. For example, as shown in FIG. 2, at 215, the network device 120 may determine the above one or more priority thresholds, and at 220, transmit the above one or more priority thresholds to the terminal device 110. The one or more priority thresholds may be transmitted via an RRC signaling, and/or a MAC CE. For example, a respective one of the one or more priority thresholds may be indicated by an absolute value of the respective priority threshold. As another example, a respective one of the one or more priority thresholds may be indicated by a difference value (i.e. a delta) relative to a previous priority level. Alternatively or additionally, the above one or more priority thresholds may be pre-defined.

In some example embodiments, the above terminal device-based PDCP duplication may be limited to the case when the network device 120 is not congested, for example, when protocol data unit (PDU) set importance (PSI) based discarding is not activated. In other words, in this case, the terminal device 110 may activate PDCP duplication for the RB if it determines that the network device 120 is not congested. The terminal device 110 may determine that the network device 120 is not congested if PSI-based discarding is not activated.

In some example embodiments, different propriety thresholds may be configured when the network device 120 is congested or not. In this case, a respective one of the above one or more priority thresholds may comprise a first target threshold when the network device 120 is congested, or a second target threshold when the network device 120 is not congested.

According to some embodiments with reference to FIG. 2, by configuring an RB with PDCP duplication (and optionally the appropriate priority threshold (s) ) , a priority change of the primary LCH that takes place at the terminal device can be automatically accompanied by the activation or deactivation of PDCP duplication. This increases the chances of having urgent data reaching the network device without the extra delay and overhead caused by downlink MAC CE (s) . Otherwise, by the time the network device realizes that an LCH needs to increase its priority and sends a MAC CE in DL to activate PDCP duplication, the corresponding data might have already been discarded.

FIG. 3 illustrates a flowchart 300 of a method implemented at a terminal device according to some embodiments of the present disclosure. For the purpose of discussion, the method 300 will be described from the perspective of the terminal device 110 with reference to FIG. 1A.

At block 310, the terminal device 110 determines a change of a priority level of a logical channel (LCH) of a radio bearer (RB) .

At block 320, the terminal device 110, based on determining that the priority level increases, activates packet data convergence protocol (PDCP) duplication for the RB, or based on determining that the priority level decreases, deactivates PDCP duplication for the RB.

In some example embodiments, the primary LCH may comprise a primary LCH of the RB.

In some example embodiments, to activate PDCP duplication for the RB, the terminal device 110 may, based on determining that the priority level is higher than or equal to a first threshold, activate PDCP duplication for the RB. In some example embodiments, to activate PDCP duplication for the RB, the terminal device 110 may activate PDCP duplication on one or more secondary LCHs. In some example embodiments, to deactivate PDCP duplication for the RB, the terminal device 110 may, based on determining that the priority level is lower than the first threshold, deactivate PDCP duplication for the RB. In some example embodiments, to deactivate PDCP duplication for the RB, the terminal device 110 may, based on determining that the priority level is lower than a second threshold, deactivate PDCP duplication for the RB. In some example embodiments, to deactivate PDCP duplication for the RB, the terminal device 110 may deactivate PDCP duplication on one or more secondary LCHs.

In some example embodiments, to activate PDCP duplication for the RB, the terminal device 110 may, based on determining that the priority level is higher than or equal to a third threshold, activate PDCP duplication on a first number of secondary LCHs, and based on determining that the priority level is higher than or equal to a fourth threshold, activate PDCP duplication on a second number of secondary LCHs. In some example embodiments, to deactivate PDCP duplication for the RB, the terminal device 110 may, based on determining that the priority level is lower than a fifth threshold, deactivate PDCP duplication on a third number of secondary LCHs, and based on determining that the priority level is lower than a sixth threshold, deactivate PDCP duplication on a fourth number of secondary LCHs.

In some example embodiments, at least one of the first threshold, the second threshold, the third threshold, the fourth threshold, the fifth threshold, or the sixth threshold may be received from a network device 120. In some example embodiments, at least one of the first threshold, the second threshold, the third threshold, the fourth threshold, the fifth threshold, or the sixth threshold may be received via at least one of the following: a radio resource control (RRC) signaling; or a media access control control element (MAC CE) . In some example embodiments, a respective threshold of the first threshold, the second threshold, the third threshold, the fourth threshold, the fifth threshold, or the sixth threshold may be indicated by one of the following: an absolute value of the respective threshold; or a difference value relative to a previous priority level.

In some example embodiments, to activate PDCP duplication for the RB, the terminal device 110 may, based on determining that a network device 120 is not congested, activate PDCP duplication for the RB. In some example embodiments, to determine that the network device 120 is not congested, the terminal device may determine that protocol data unit (PDU) set importance (PSI) based discarding is not activated.

In some example embodiments, a respective threshold of the first threshold, the second threshold, the third threshold, the fourth threshold, the fifth threshold, or the sixth threshold may comprise one of the following: a first target threshold when a network device 120 is congested; or a second target threshold when the network device 120 is not congested.

In some example embodiments, to determine the change of the priority level of the primary LCH, the terminal device 110 may determine the change of the priority level based on an indication indicating the change from a network device 120.

In some example embodiments, to determine the change of the priority level of the primary LCH, the terminal device 110 may determine the change of the priority level at the terminal device without an indication associated with the change from a network device 120. In some example embodiments, to determine the change of the priority level of the primary LCH, the terminal device 110 may determine the change of the priority level based on one of the following: a delay criterion associated with buffered data; or an amount of the buffered data.

In some example embodiments, to determine that the priority level increases, the terminal device may determine that a priority value of the LCH decreases, and/or to determine that the priority level decreases, the terminal device 110 may determine that a priority value of the LCH increases.

FIG. 4 illustrates a flowchart 400 of a method implemented at a network device according to some embodiments of the present disclosure. For the purpose of discussion, the method 400 will be described from the perspective of the network device 120 with reference to FIG. 1A.

At block 410, the network device 120 determines one or more thresholds of a priority level of a logical channel (LCH) of a radio bearer (RB) , the one or more thresholds being used for a terminal device 110 to activate or deactivate packet data convergence protocol (PDCP) duplication for the RB.

At block 420, the network device 120 transmits the one or more thresholds to the terminal device 110.

In some example embodiments, the one or more thresholds may be transmitted via at least one of the following: a radio resource control (RRC) signaling; or a media access control control element (MAC CE) .

In some example embodiments, a respective threshold of the one or more thresholds may be indicated by one of the following: an absolute value of the respective threshold; or a difference value relative to a previous priority level.

In some example embodiments, a respective threshold of the one or more thresholds may comprise one of the following: a first target threshold when the network device 120 is congested; or a second target threshold when the network device 120 is not congested.

In some example embodiments, the one or more thresholds may comprise a first threshold, and the terminal device 110 may activate PDCP duplication for the RB if the priority level is higher than or equal to the first threshold. In some example embodiments, the terminal device 110 may activate PDCP duplication on one or more secondary LCHs. In some example embodiments, the terminal device 110 may deactivate PDCP duplication for the RB if the priority level is lower than the first threshold. In some example embodiments, the one or more thresholds further comprise a second threshold, and the terminal device 110 may deactivate PDCP duplication for the RB if the priority level is lower than the second threshold. In some example embodiments, the terminal device 110 may deactivate PDCP duplication on one or more secondary LCHs.

In some example embodiments, the one or more thresholds may comprise a third threshold and a fourth threshold, and the terminal device 110 may activate PDCP duplication on a first number of secondary LCHs if the priority level is higher than or equal to the third threshold, and the terminal device 110 may activate PDCP duplication on a second number of secondary LCHs if the priority level is higher than or equal to the fourth threshold.

In some example embodiments, the one or more thresholds comprise a fifth threshold and a sixth threshold, and the terminal device 110 may deactivate PDCP duplication on a third number of secondary LCHs if the priority level is lower than the fifth threshold, and the terminal device 110 may deactivate PDCP duplication on a fourth number of secondary LCHs if the priority level is lower than the sixth threshold.

In some example embodiments, the network device 120 may further transmit, to the terminal device 110, an indication indicating a change of the priority level of the primary LCH.

In some example embodiments, an apparatus capable of performing the method 300 (for example, the terminal device 110) may comprise means for performing the respective steps of the method 300. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

In some example embodiments, the apparatus comprises means for determining a change of a priority level of a logical channel (LCH) of a radio bearer (RB) ; and one of the following: means for based on determining that the priority level increases, activating packet data convergence protocol (PDCP) duplication for the RB; or means for based on determining that the priority level decreases, deactivating PDCP duplication for the RB.

In some example embodiments, the primary LCH comprises a primary LCH of the RB.

In some example embodiments, the means for activating PDCP duplication for the RB comprises: means for, based on determining that the priority level is higher than or equal to a first threshold, activating PDCP duplication for the RB. In some example embodiments, the means for activating PDCP duplication for the RB comprises means for activating PDCP duplication on one or more secondary LCHs. In some example embodiments, the means for deactivating PDCP duplication for the RB comprises means for, based on determining that the priority level is lower than the first threshold, deactivating PDCP duplication for the RB. In some example embodiments, the means for deactivating PDCP duplication for the RB comprises means for, based on determining that the priority level is lower than a second threshold, deactivating PDCP duplication for the RB. In some example embodiments, the means for deactivating PDCP duplication for the RB comprise means for deactivating PDCP duplication on one or more secondary LCHs.

In some example embodiments, the means for activating PDCP duplication for the RB comprises means for, based on determining that the priority level is higher than or equal to a third threshold, activating PDCP duplication on a first number of secondary LCHs; and means for, based on determining that the priority level is higher than or equal to a fourth threshold, activating PDCP duplication on a second number of secondary LCHs.

In some example embodiments, the means for deactivating PDCP duplication for the RB comprises means for, based on determining that the priority level is lower than a fifth threshold, deactivating PDCP duplication on a third number of secondary LCHs; and means for, based on determining that the priority level is lower than a sixth threshold, deactivating PDCP duplication on a fourth number of secondary LCHs.

In some example embodiments, at least one of the first threshold, the second threshold, the third threshold, the fourth threshold, the fifth threshold, or the sixth threshold is received from a network device. In some example embodiments, at least one of the first threshold, the second threshold, the third threshold, the fourth threshold, the fifth threshold, or the sixth threshold is received via at least one of the following: a radio resource control (RRC) signaling; or a media access control control element (MAC CE) . In some example embodiments, a respective threshold of the first threshold, the second threshold, the third threshold, the fourth threshold, the fifth threshold, or the sixth threshold is indicated by one of the following: an absolute value of the respective threshold; or a difference value relative to a previous priority level.

In some example embodiments, the means for activating PDCP duplication for the RB comprises means for, based on determining that a network device is not congested, activating PDCP duplication for the RB. In some example embodiments, the means for determining that the network device is not congested comprises means for determining that protocol data unit (PDU) set importance (PSI) based discarding is not activated.

In some example embodiments, a respective threshold of the first threshold, the second threshold, the third threshold, the fourth threshold, the fifth threshold, or the sixth threshold comprises one of the following: a first target threshold when a network device is congested; or a second target threshold when the network device is not congested.

In some example embodiments, the means for determining the change of the priority level of the primary LCH comprises means for determining the change of the priority level based on an indication indicating the change from a network device.

In some example embodiments, the means for determining the change of the priority level of the primary LCH comprises means for determining the change of the priority level at the terminal device without an indication associated with the change from a network device. In some example embodiments, the means for determining the change of the priority level of the primary LCH comprises means for determining the change of the priority level based on one of the following: a delay criterion associated with buffered data; or an amount of the buffered data.

In some example embodiments, the means for determining that the priority level increases comprises means for determining that a priority value of the LCH decreases and/or the means for determining that the priority level decreases comprises means for determining that a priority value of the LCH increases.

In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of the method 300. In some embodiments, the means comprises at least one processor and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

In some example embodiments, an apparatus capable of performing the method 400 (for example, the network device 120) may comprise means for performing the respective steps of the method 400. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

In some example embodiments, the apparatus comprises means for determining one or more thresholds of a priority level of a logical channel (LCH) of a radio bearer (RB) , the one or more thresholds being used for a terminal device to activate or deactivate packet data convergence protocol (PDCP) duplication for the RB; and means for transmitting the one or more thresholds to the terminal device.

In some example embodiments, the one or more thresholds are transmitted via at least one of the following: a radio resource control (RRC) signaling; or a media access control control element (MAC CE) .

In some example embodiments, a respective threshold of the one or more thresholds is indicated by one of the following: an absolute value of the respective threshold; or a difference value relative to a previous priority level.

In some example embodiments, a respective threshold of the one or more thresholds comprises one of the following: a first target threshold when the network device is congested; or a second target threshold when the network device is not congested.

In some example embodiments, the primary LCH comprises a primary LCH of the RB.

In some example embodiments, the one or more thresholds comprise a first threshold, and the terminal device activates PDCP duplication for the RB if the priority level is higher than or equal to the first threshold. In some example embodiments, the terminal device activates PDCP duplication on one or more secondary LCHs. In some example embodiments, the terminal device deactivates PDCP duplication for the RB if the priority level is lower than the first threshold. In some example embodiments, the one or more thresholds further comprise a second threshold, and the terminal device deactivates PDCP duplication for the RB if the priority level is lower than the second threshold. In some example embodiments, the terminal device deactivates PDCP duplication on one or more secondary LCHs.

In some example embodiments, the one or more thresholds comprise a third threshold and a fourth threshold, and the terminal device activates PDCP duplication on a first number of secondary LCHs if the priority level is higher than or equal to the third threshold, and the terminal device activates PDCP duplication on a second number of secondary LCHs if the priority level is higher than or equal to the fourth threshold.

In some example embodiments, the one or more thresholds comprise a fifth threshold and a sixth threshold, and the terminal device deactivates PDCP duplication on a third number of secondary LCHs if the priority level is lower than the fifth threshold, and the terminal device deactivates PDCP duplication on a fourth number of secondary LCHs if the priority level is lower than the sixth threshold.

In some example embodiments, the apparatus further comprises means for transmitting, to the terminal device, an indication indicating a change of the priority level of the primary LCH.

In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of the method 400. In some embodiments, the means comprises at least one processor and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

FIG. 5 illustrates a simplified block diagram of a device 500 that is suitable for implementing some example embodiments of the present disclosure. The device 500 may be provided to implement the communication device, for example, the terminal device 110, or the network device 120 as shown in FIG. 1A. As shown, the device 500 includes one or more processors 510, one or more memories 520 coupled to the processor 510, and one or more communication modules 540 coupled to the processor 510.

The communication module 540 is for bidirectional communications. The communication module 540 has at least one antenna to facilitate communication. The communication interface may represent any interface that is necessary for communication with other network elements.

The processor 510 may be of any type suitable to the local technical network and may include one or more of the following: general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 500 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.

The memory 520 may include one or more non-volatile memories and one or more volatile memories. Examples of the non-volatile memories include, but are not limited to, a Read Only Memory (ROM) 524, an electrically programmable read only memory (EPROM) , a flash memory, a hard disk, a compact disc (CD) , a digital video disk (DVD) , and other magnetic storage and/or optical storage. Examples of the volatile memories include, but are not limited to, a random access memory (RAM) 522 and other volatile memories that will not last in the power-down duration.

A computer program 530 includes computer executable instructions that are executed by the associated processor 510. The program 530 may be stored in the ROM 524. The processor 510 may perform any suitable actions and processing by loading the program 530 into the RAM 522.

The embodiments of the present disclosure may be implemented by means of the program 530 so that the device 500 may perform any process of the disclosure as discussed with reference to FIG. 2. The embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

In some example embodiments, the program 530 may be tangibly contained in a computer readable medium which may be included in the device 500 (such as in the memory 520) or other storage devices that are accessible by the device 500. The device 500 may load the program 530 from the computer readable medium to the RAM 522 for execution. The computer readable medium may include any types of tangible non-volatile storage, such as ROM, EPROM, a flash memory, a hard disk, CD, DVD, and the like.

FIG. 6 illustrates a block diagram of an example of a computer readable medium 600 in accordance with some example embodiments of the present disclosure. The computer readable medium 600 has the program 530 stored thereon. It is noted that although the computer readable medium 600 is depicted in form of CD or DVD in FIG. 6, the computer readable medium 600 may be in any other form suitable for carrying or holding the program 530.

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

The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, being executed in a device on a target real or virtual processor, to carry out the method as described above with reference to any of FIGS. 3 and 4. 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.

In the context of the present disclosure, the computer program codes or related data may be carried by any suitable carrier to enable the device, apparatus or processor to perform various processes and operations as described above. Examples of the carrier include a signal, computer readable medium, and the like.

The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the computer readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM) , a read-only memory (ROM) , an erasable programmable read-only memory (EPROM or Flash memory) , an optical fiber, a portable compact disc read-only memory (CD-ROM) , an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. The term “non-transitory, ” as used herein, is a limitation of the medium itself (i.e., tangible, not a signal) as opposed to a limitation on data storage persistency (e.g., RAM vs.ROM) .

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

Claims

A terminal device comprising:

at least one processor; and

at least one memory storing instructions that, when executed by the at least one processor, cause the terminal device at least to:

determine a change of a priority level of a logical channel (LCH) of a radio bearer (RB) ; and

one of the following:

based on determining that the priority level increases, activate packet data convergence protocol (PDCP) duplication for the RB; or

based on determining that the priority level decreases, deactivate PDCP duplication for the RB.
The terminal device of claim 1, wherein the primary LCH comprises a primary LCH of the RB.
The terminal device of claim 2, wherein activating PDCP duplication for the RB comprises:

based on determining that the priority level is higher than or equal to a first threshold, activating PDCP duplication for the RB.
The terminal device of claim 3, wherein activating PDCP duplication for the RB comprises:

activating PDCP duplication on one or more secondary LCHs.
The terminal device of claim 3, wherein deactivating PDCP duplication for the RB comprises:

based on determining that the priority level is lower than the first threshold, deactivating PDCP duplication for the RB.
The terminal device of claim 3, wherein deactivating PDCP duplication for the RB comprises:

based on determining that the priority level is lower than a second threshold, deactivating PDCP duplication for the RB.
The terminal device of claim 5 or 6, wherein deactivating PDCP duplication for the RB comprises:

deactivating PDCP duplication on one or more secondary LCHs.
The terminal device of claim 2, wherein activating PDCP duplication for the RB comprises:

based on determining that the priority level is higher than or equal to a third threshold, activating PDCP duplication on a first number of secondary LCHs; and

based on determining that the priority level is higher than or equal to a fourth threshold, activating PDCP duplication on a second number of secondary LCHs.
The terminal device of claim 2 or 8, wherein deactivating PDCP duplication for the RB comprises:

based on determining that the priority level is lower than a fifth threshold, deactivating PDCP duplication on a third number of secondary LCHs; and

based on determining that the priority level is lower than a sixth threshold, deactivating PDCP duplication on a fourth number of secondary LCHs.
The terminal device of any of claims 3-9, wherein at least one of the first threshold, the second threshold, the third threshold, the fourth threshold, the fifth threshold, or the sixth threshold is received from a network device.
The terminal device of claim 10, wherein at least one of the first threshold, the second threshold, the third threshold, the fourth threshold, the fifth threshold, or the sixth threshold is received via at least one of the following:

a radio resource control (RRC) signaling; or

a media access control control element (MAC CE) .
The terminal device of claim 10 or 11, wherein a respective threshold of the first threshold, the second threshold, the third threshold, the fourth threshold, the fifth threshold, or the sixth threshold is indicated by one of the following:

an absolute value of the respective threshold; or

a difference value relative to a previous priority level.
The terminal device of any of claims 1-12, wherein activating PDCP duplication for the RB comprises:

based on determining that a network device is not congested, activating PDCP duplication for the RB.
The terminal device of claim 13, wherein determining that the network device is not congested comprises:

determining that protocol data unit (PDU) set importance (PSI) based discarding is not activated.
The terminal device of any of claims 3-9, wherein a respective threshold of the first threshold, the second threshold, the third threshold, the fourth threshold, the fifth threshold, or the sixth threshold comprises one of the following:

a first target threshold when a network device is congested; or

a second target threshold when the network device is not congested.
The terminal device of any of claims 1-15, wherein determining the change of the priority level of the primary LCH comprises:

determining the change of the priority level based on an indication indicating the change from a network device.
The terminal device of any of claims 1-15, wherein determining the change of the priority level of the primary LCH comprises:

determining the change of the priority level at the terminal device without an indication associated with the change from a network device.
The terminal device of claim 17, wherein determining the change of the priority level of the primary LCH comprises:

determining the change of the priority level based on one of the following:

a delay criterion associated with buffered data; or

an amount of the buffered data.
The terminal device of claim 1, wherein at least one of:

determining that the priority level increases comprises determining that a priority value of the LCH decreases; or

determining that the priority level decreases comprises determining that a priority value of the LCH increases.
A network device comprising:

at least one processor; and

at least one memory storing instructions that, when executed by the at least one processor, cause the network device at least to:

determine one or more thresholds of a priority level of a logical channel (LCH) of a radio bearer (RB) , the one or more thresholds being used for a terminal device to activate or deactivate packet data convergence protocol (PDCP) duplication for the RB; and

transmit the one or more thresholds to the terminal device.
The network device of claim 20, wherein the one or more thresholds are transmitted via at least one of the following:

a radio resource control (RRC) signaling; or

a media access control control element (MAC CE) .
The network device of claim 20 or 21, wherein a respective threshold of the one or more thresholds is indicated by one of the following:

an absolute value of the respective threshold; or

a difference value relative to a previous priority level.
The network device of any of claims 20-22, wherein a respective threshold of the one or more thresholds comprises one of the following:

a first target threshold when the network device is congested; or

a second target threshold when the network device is not congested.
The network device of any of claims 20-23, wherein the primary LCH comprises a primary LCH of the RB.
The network device of claim 24, wherein the one or more thresholds comprise a first threshold, and the terminal device activates PDCP duplication for the RB if the priority level is higher than or equal to the first threshold.
The network device of claim 25, wherein the terminal device activates PDCP duplication on one or more secondary LCHs.
The network device of claim 25, wherein the terminal device deactivates PDCP duplication for the RB if the priority level is lower than the first threshold.
The network device of claim 25, wherein the one or more thresholds further comprise a second threshold, and the terminal device deactivates PDCP duplication for the RB if the priority level is lower than the second threshold.
The network device of claim 27 or 28, wherein the terminal device deactivates PDCP duplication on one or more secondary LCHs.
The network device of claim 24, wherein the one or more thresholds comprise a third threshold and a fourth threshold, and the terminal device activates PDCP duplication on a first number of secondary LCHs if the priority level is higher than or equal to the third threshold, and the terminal device activates PDCP duplication on a second number of secondary LCHs if the priority level is higher than or equal to the fourth threshold.
The network device of claim 24 or 30, wherein the one or more thresholds comprise a fifth threshold and a sixth threshold, and the terminal device deactivates PDCP duplication on a third number of secondary LCHs if the priority level is lower than the fifth threshold, and the terminal device deactivates PDCP duplication on a fourth number of secondary LCHs if the priority level is lower than the sixth threshold.
The network device of any of claims 24-31, wherein the network device is further caused to:

transmit, to the terminal device, an indication indicating a change of the priority level of the primary LCH.
A method comprising:

determining, at a terminal device, a change of a priority level of a logical channel (LCH) of a radio bearer (RB) ; and

one of the following:

based on determining that the priority level increases, activating, at the terminal device, packet data convergence protocol (PDCP) duplication for the RB; or

based on determining that the priority level decreases, deactivating, at the terminal device, PDCP duplication for the RB.
A method comprising:

determining, at a network device, one or more thresholds of a priority level of a logical channel (LCH) of a radio bearer (RB) , the one or more thresholds being used for a terminal device to activate or deactivate packet data convergence protocol (PDCP) duplication for the RB; and

transmitting, at the network device, the one or more thresholds to the terminal device.
An apparatus comprising:

means for determining, at a terminal device, a change of a priority level of a logical channel (LCH) of a radio bearer (RB) ; and

one of the following:

means for, based on determining that the priority level increases, activating, at the terminal device, packet data convergence protocol (PDCP) duplication for the RB; or

means for, based on determining that the priority level decreases, deactivating, at the terminal device, PDCP duplication for the RB.
An apparatus comprising:

means for determining, at a network device, one or more thresholds of a priority level of a logical channel (LCH) of a radio bearer (RB) , the one or more thresholds being used for a terminal device to activate or deactivate packet data convergence protocol (PDCP) duplication for the RB; and

means for transmitting, at the network device, the one or more thresholds to the terminal device.
A non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the method of claim 33 or 34.