Enhancement of packet data convergence protocol duplication framework

Abstract

Example embodiments of the present disclosure are directed to enhancement of a packet data convergence protocol, PDCP, duplication framework A method comprises determining that a packet from a packet data convergence protocol, PDCP, entity of the first apparatus is to be duplicated on a plurality of radio link control, RLC, entities of the first apparatus; assigning, based on the determination by at least one linked RLC entity, duplicated PDCP packets across a plurality of radio link control, RLC, entities of the first apparatus with a common RLC sequence number, SN; and transmitting the duplicated PDCP packets with the common RLC SN to a second apparatus.

Description

ENHANCEMENT OF PACKET DATA CONVERGENCE PROTOCOL DUPLICATION FRAMEWORKFIELD

[0001] Various example embodiments of the present disclosure generally relate to the field of telecommunication and in particular, to methods, devices, apparatuses and computer readable storage medium for enhanced packet data convergence protocol (PDCP) duplication.BACKGROUND

[0002] With the progression towards 6G networks, enhancing the reliability and efficiency of data transmission is critical. In this case, PDCP duplication improves transmission reliability by duplicating packets and sending them over multiple paths to mitigate the impact of link failures or delays. As 6G networks introduce more complex and dynamic scenarios, enhancing PDCP duplication is essential to meet the performance requirements of different kinds of application scenarios.SUMMARY

[0003] In a first aspect of the present disclosure, there is provided a first apparatus. The first apparatus comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus to: determine that a packet from a PDCP entity of the first apparatus is to be duplicated on a plurality of RLC entities of the first apparatus; assign, based on the determination by at least one linked RLC entity, duplicated PDCP packets across a plurality of RLC entities of the first apparatus with a common RLC SN; and transmit the duplicated PDCP packets with the common RLC SN to a second apparatus.

[0004] In a second aspect of the present disclosure, there is provided a second apparatus. The second apparatus comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the second apparatus to: receive, at a plurality of RLC entities of the second apparatus, duplicated PDCP packets from a first apparatus; cause the duplicated PDCP packets to be delivered from the plurality of RLC entities to at least one linked RLC entity of the second apparatus; inaccordance with a determination that the duplicated PDCP packets are assigned with a common RLC SN, re-assemble, by the at least one linked RLC entity, an RLC data unit based on at least one duplicated PDCP packet of the duplicated PDCP packets; and cause the reassembled RLC data unit to be sent to a PDCP entity of the second apparatus.

[0005] In a third aspect of the present disclosure, there is provided a first apparatus. The first apparatus comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus to: determine that a packet from a PDCP entity of the first apparatus is to be duplicated on a plurality of RLC entities of the first apparatus; assign, by the PDCP entity based on the determination, duplicated PDCP packets across a plurality of RLC entities of the first apparatus with a common RLC SN; and transmit the duplicated PDCP packets with the common RLC SN to a second apparatus.

[0006] In a fourth aspect of the present disclosure, there is provided a second apparatus. The second apparatus comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the second apparatus to: receive, at a plurality of RLC entities of the second apparatus, duplicated PDCP packets from a first apparatus; in accordance with a determination that the duplicated PDCP packets are assigned with a common RLC SN, re-assemble, by a PDCP entity of the second apparatus, an RLC data unit based on at least one duplicated PDCP packet of the duplicated PDCP packets.

[0007] In a fifth aspect of the present disclosure, there is provided a first apparatus. The first apparatus comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus to: determine a mapping between RLC SNs and PDCP SNs; in accordance with a determination that a packet from a PDCP entity of the first apparatus is to be duplicated on a plurality of RLC entities of the first apparatus, determine, by a plurality of RLC entities, a same RLC SN of duplicated PDCP packets across the plurality of RLC entities based on the mapping and a PDCP SN of the duplicated PDCP packets; and transmit the duplicated PDCP packets with the same RLC SN to a second apparatus.

[0008] In a sixth aspect of the present disclosure, there is provided a second apparatus. The second apparatus comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the second apparatusto: receive duplicated PDCP packets from a first apparatus; and in accordance with a determination that the duplicated PDCP packets are with a same RLC SN, re-assemble an RLC data unit based on at least one duplicated PDCP packet of the duplicated PDCP packets.

[0009] In a seventh aspect of the present disclosure, there is provided a method. The method comprises: determining that a packet from a PDCP entity of the first apparatus is to be duplicated on a plurality of RLC entities of the first apparatus; assigning, based on the determination by at least one linked RLC entity, duplicated PDCP packets across a plurality of RLC entities of the first apparatus with a common RLC SN; and transmitting the duplicated PDCP packets with the common RLC SN to a second apparatus.

[0010] In an eighth aspect of the present disclosure, there is provided a method. The method comprises: receiving, at a plurality of RLC entities of the second apparatus, duplicated PDCP packets from a first apparatus; causing the duplicated PDCP packets to be delivered from the plurality of RLC entities to at least one linked RLC entity of the second apparatus; in accordance with a determination that the duplicated PDCP packets are assigned with a common RLC SN, re-assembling by the at least one linked RLC entity, an RLC data unit based on at least one duplicated PDCP packet of the duplicated PDCP packets; and causing the reassembled RLC data unit to be sent to a PDCP entity of the second apparatus.

[0011] In a ninth aspect of the present disclosure, there is provided a method. The method comprises: determining that a packet from a PDCP entity of the first apparatus is to be duplicated on a plurality of RLC entities of the first apparatus; assigning, by the PDCP entity based on the determination, duplicated PDCP packets across a plurality of RLC entities of the first apparatus with a common RLC SN; and transmitting the duplicated PDCP packets with the common RLC SN to a second apparatus.

[0012] In a tenth aspect of the present disclosure, there is provided a method. The method comprises: receiving, at a plurality of RLC entities of the second apparatus, duplicated PDCP packets from a first apparatus; in accordance with a determination that the duplicated PDCP packets are assigned with a common RLC SN, re-assembling by a PDCP entity of the second apparatus, an RLC data unit based on at least one duplicated PDCP packet of the duplicated PDCP packets.

[0013] In an eleventh aspect of the present disclosure, there is provided a method. Themethod comprises: determining a mapping between RLC SNs and PDCP SNs; in accordance with a determination that a packet from a PDCP entity of the first apparatus is to be duplicated on a plurality of RLC entities of the first apparatus, determining by a plurality of RLC entities, a same RLC SN of duplicated PDCP packets across the plurality of RLC entities based on the mapping and a PDCP SN of the duplicated PDCP packets; and transmitting the duplicated PDCP packets with the same RLC SN to a second apparatus.

[0014] In a twelfth aspect of the present disclosure, there is provided a method. The method comprises: receiving duplicated PDCP packets from a first apparatus; and in accordance with a determination that the duplicated PDCP packets are with a same RLC SN, re-assembling an RLC data unit based on at least one duplicated PDCP packet of the duplicated PDCP packets.

[0015] In a thirteenth aspect of the present disclosure, there is provided a first apparatus. The first apparatus comprises means for determining that a packet from a PDCP entity of the first apparatus is to be duplicated on a plurality of RLC entities of the first apparatus; means for assigning, based on the determination by at least one linked RLC entity, duplicated PDCP packets across a plurality of RLC entities of the first apparatus with a common RLC SN; and means for transmitting the duplicated PDCP packets with the common RLC SN to a second apparatus.

[0016] In a fourteenth aspect of the present disclosure, there is provided a second apparatus. The second apparatus comprises means for receiving, at a plurality of RLC entities of the second apparatus, duplicated PDCP packets from a first apparatus; means for causing the duplicated PDCP packets to be delivered from the plurality of RLC entities to at least one linked RLC entity of the second apparatus; means for in accordance with a determination that the duplicated PDCP packets are assigned with a common RLC SN, reassembling by the at least one linked RLC entity, an RLC data unit based on at least one duplicated PDCP packet of the duplicated PDCP packets; and means for causing the reassembled RLC data unit to be sent to a PDCP entity of the second apparatus.

[0017] In a fifteenth aspect of the present disclosure, there is provided a first apparatus. The first apparatus comprises means for determining that a packet from a PDCP entity of the first apparatus is to be duplicated on a plurality of RLC entities of the first apparatus; means for assigning, by the PDCP entity based on the determination, duplicated PDCPpackets across a plurality of RLC entities of the first apparatus with a common RLC SN; and means for transmitting the duplicated PDCP packets with the common RLC SN to a second apparatus.

[0018] In a sixteenth aspect of the present disclosure, there is provided a second apparatus. The second apparatus comprises means for receiving, at a plurality of RLC entities of the second apparatus, duplicated PDCP packets from a first apparatus; means for in accordance with a determination that the duplicated PDCP packets are assigned with a common RLC SN, re-assembling by a PDCP entity of the second apparatus, an RLC data unit based on at least one duplicated PDCP packet of the duplicated PDCP packets.

[0019] In a seventeenth aspect of the present disclosure, there is provided a first apparatus. The first apparatus comprises means for determining a mapping between RLC SNs and PDCP SNs; means for in accordance with a determination that a packet from a PDCP entity of the first apparatus is to be duplicated on a plurality of RLC entities of the first apparatus, determining by a plurality of RLC entities, a same RLC SN of duplicated PDCP packets across the plurality of RLC entities based on the mapping and a PDCP SN of the duplicated PDCP packets; and means for transmitting the duplicated PDCP packets with the same RLC SN to a second apparatus.

[0020] In an eighteenth aspect of the present disclosure, there is provided a second apparatus. The second apparatus comprises means for receiving duplicated PDCP packets from a first apparatus; and means for in accordance with a determination that the duplicated PDCP packets are with a same RLC SN, re-assembling an RLC data unit based on at least one duplicated PDCP packet of the duplicated PDCP packets.

[0021] In a nineteenth aspect of the present disclosure, there is provided a computer readable medium. The computer readable medium comprises instructions stored thereon for causing an apparatus to perform at least the method according to any of the seventh, eighth, ninth, tenth, eleventh, or twelfth aspect.

[0022] 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

[0023] Some example embodiments will now be described with reference to the accompanying drawings, where:

[0024] FIG. 1 illustrates an example communication environment in which example embodiments of the present disclosure can be implemented;

[0025] FIG. 2 illustrates a schematic diagram of a PDCP duplication up to four RLC entities from transmitter perspective;

[0026] FIG. 3 illustrates a schematic diagram of a PDCP duplication up to four RLC entities from receiver perspective;

[0027] FIG. 4 illustrates an example signaling flow of enhanced PDCP duplication according to some example embodiments of the present disclosure;

[0028] FIG. 5 illustrates a schematic diagram of a PDCP duplication with separate linked RLC entity from transmitter perspective according to some example embodiments of the present disclosure;

[0029] FIG. 6 illustrates a schematic diagram of a PDCP duplication with common linked RLC entity from transmitter perspective according to some example embodiments of the present disclosure;

[0030] FIG. 7 illustrates a schematic diagram of a PDCP duplication with common linked RLC entity from receiver perspective according to some example embodiments of the present disclosure;

[0031] FIG. 8 illustrates a schematic diagram of a PDCP duplication with separate linked RLC entity from receiver perspective according to some example embodiments of the present disclosure;

[0032] FIG. 9 illustrates a schematic diagram of duplication RLC activation or deactivation medium access control-control element (MAC CE) according to some example embodiments of the present disclosure;

[0033] FIG. 10 illustrates a schematic diagram of an example scenario of RLC protocol data unit (PDU) with SN according to some example embodiments of the present disclosure;

[0034] FIG. 11 illustrates a schematic diagram of reassembling a segmented PDU fromassociated RLC entities according to some example embodiments of the present disclosure;

[0035] FIG. 12 illustrates another example signaling flow of enhanced PDCP duplication according to some example embodiments of the present disclosure;

[0036] FIG. 13 illustrates another example signaling flow of enhanced PDCP duplication according to some example embodiments of the present disclosure;

[0037] FIG. 14 illustrates a flowchart of enhanced PDCP duplication from transmitter perspective according to some example embodiments of the present disclosure;

[0038] FIG. 15 illustrates a flowchart of enhanced PDCP duplication from receiver perspective according to some example embodiments of the present disclosure;

[0039] FIG. 16 illustrates a flowchart of a method implemented at a first apparatus in accordance with some example embodiments of the present disclosure;

[0040] FIG. 17 illustrates a flowchart of a method implemented at a second apparatus in accordance with some example embodiments of the present disclosure;

[0041] FIG. 18 illustrates a flowchart of a method implemented at a first apparatus in accordance with some example embodiments of the present disclosure;

[0042] FIG. 19 illustrates a flowchart of a method implemented at a second apparatus in accordance with some example embodiments of the present disclosure;

[0043] FIG. 20 illustrates a flowchart of a method implemented at a first apparatus in accordance with some example embodiments of the present disclosure;

[0044] FIG. 21 illustrates a flowchart of a method implemented at a second apparatus in accordance with some example embodiments of the present disclosure;

[0045] FIG. 22 illustrates a simplified block diagram of a device that is suitable for implementing example embodiments of the present disclosure; and

[0046] FIG. 23 illustrates a block diagram of an example computer readable medium in accordance with some example embodiments of the present disclosure.

[0047] Throughout the drawings, the same or similar reference numerals represent the same or similar element.DETAILED DESCRIPTION

[0048] 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.

[0049] 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.

[0050] 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.

[0051] It shall be understood that although the terms “first,” “second,”..., etc. in front of noun(s) and the like may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another and they do not limit the order of the noun(s). 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.

[0052] As used herein, “at least one of the following: ” and “at least one of ” and similar wording, where the list of two or more elements 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.

[0053] As used herein, unless stated explicitly, performing a step “in response to A” does not indicate that the step is performed immediately after “A” occurs and one or more intervening steps may be included.

[0054] The terminology used herein is for the purpose of describing particular embodiments only 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.

[0055] 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.

[0056] 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.

[0057] 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 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), 5.5G, the sixth generation (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.

[0058] As used herein, the term “network device” refers to a node in a communication network via which a terminal device accesses the network and receives 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), an evolved NodeB (eNodeB or eNB), an NR NB (also referred to as a gNB), a Remote Radio Unit (RRU), a radio header (RH), a remote radio head (RRH), a relay, an Integrated Access and Backhaul (IAB) node, a low power node such as a femto, a pico, a non-terrestrial network (NTN) or non-ground network device such as a satellite network device, a low earth orbit (LEO) satellite and a geosynchronous earth orbit (GEO) satellite, an aircraft network device, and so forth, depending on the applied terminology and technology. In some example embodiments, radio access network (RAN) split architecture comprises a Centralized Unit (CU) and a Distributed Unit (DU) at an IAB donor node. An IAB node comprises a Mobile Terminal (IAB-MT) part that behaves like a UE toward the parent node, and a DU part of an IAB node behaves like a base station toward the next-hop IAB node.

[0059] 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 (loT) 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. The terminal device may also correspond to a Mobile Termination (MT) part of an IAB node (e.g., a relay node). In the following description, the terms “terminal device”, “communication device”, “terminal”, “user equipment” and “UE” may be used interchangeably.

[0060] As used herein, the term “resource,” “transmission resource,” “resource block,” “physical resource block” (PRB), “uplink resource,” or “downlink resource” may refer to any resource for performing a communication, for example, a communication between a terminal device and a network device, 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 combination of the time, frequency, space and / or code domain 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.

[0061] As used herein, the term "PDCP" refers to the packet data convergence protocol layer in cellular network architectures. The PDCP layer is responsible for functions such as header compression to optimize data transmission, encryption and integrity protection to ensure secure communication, and the management of data delivery over reliable and unreliable links. For example, in 5G networks, PDCP enables efficient handling of both user and control plane data, contributing to enhanced network performance and security.

[0062] As used herein, the term "RLC" refers to the radio Link control layer in cellular network architectures. The RLC layer provides key functionalities such as segmentation and reassembly of data packets, retransmission of lost data, and delivery of data in sequence to upper layers. For example, in 5G, the RLC layer supports various modes of operation — transparent, unacknowledged, and acknowledged — enabling flexibility to adapt to different Quality of Service (QoS) requirements and ensuring reliable data transfer in diverse communication scenarios.

[0063] As used herein, the term "MCG" refers to the master cell group in dual connectivity or multi-connectivity scenarios in cellular networks. The MCG typically represents the primary connection between the user equipment (UE) and the network, anchored on a master node, which is usually part of the core network’s radio access network (RAN). For example, in a dual connectivity setup, the MCG handles critical control signaling and a portion of the data transmission, ensuring a stable and robust communication link for the UE while allowing secondary connections to enhance throughput and reliability.

[0064] As used herein, the term "SCG" refers to the secondary cell group in dual connectivity or multi -connectivity scenarios in cellular networks. The SCG represents a group of cells associated with a secondary node, which supplements the primary connection provided by the MCG. For example, in a dual connectivity setup, the SCG facilitates additional data transmission and resource utilization to improve overall network performance, enhance throughput, and ensure service continuity, especially in scenarios with high data demands or challenging radio conditions.

[0065] FIG. 1 illustrates 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 first apparatus 110 and a second apparatus 120, can communicate with each other. In the example of FIG. 1, the first apparatus 110 may be a transmitter and the second apparatus 120 may be a receiver. In some examples, the first apparatus 110 may include a terminal device, for example, may be UE, and the second apparatus 120 may include a network device serving the terminal device, for example, may be a base station serving the UE. Alternatively, the first apparatus 110 may include a network device and the second apparatus 120 may include a terminal device. The serving area of the first apparatus 110 and the secondapparatus 120 may be called a cell 102.

[0066] 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. It is noted that although illustrated as a transmitter, the first apparatus 110 may be another device than a transmitter. Although illustrated as a receiver, the second apparatus 120 may be another device than a receiver.

[0067] In the following, for the purpose of illustration, some example embodiments are described with the first apparatus 110 operating as a transmitter and the second apparatus 120 operating as a receiver. However, in some example embodiments, operations described in connection with a transmitter may be implemented at a receiver or other device, and operations described in connection with a receiver may be implemented at a transmitter or other device.

[0068] In some example embodiments, a transmission direction from the first apparatus 110 to the second apparatus 120 is referred to as a downlink (DL) or an uplink (UL). In DL, the first apparatus 110 is a transmitting (TX) device (or a transmitter) and the second apparatus 120 is a receiving (RX) device (or a receiver). In UL, the first apparatus 110 is a TX device (or a transmitter) and the second apparatus 120 is a RX device (or a receiver).

[0069] Communications in the communication environment 100 may be implemented according to any proper communication protocol(s), comprising, but not limited to, cellular communication protocols, wireless local network communication protocols such as Institute for Electrical and Electronics Engineers (IEEE) 802.11 and the like, and / or any other protocols currently known or to be developed in the future. Moreover, the communication may utilize any proper wireless communication technology, comprising but not limited to: Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Frequency Division Duplex (FDD), Time Division Duplex (TDD), Multiple-Input Multiple-Output (MIMO), Orthogonal Frequency Division Multiple (OFDM), Discrete Fourier Transform spread OFDM (DFT-s-OFDM) and / or any other technologies currently known or to be developedin the future.

[0070] PDCP duplication was introduced in new radio (NR) as part of the first release (Rel. 15) to increase reliability for ultra reliable & low latency communication (URLLC) types of applications. This will continue to play an important role in XR pose information, 6G reliability use cases, etc.

[0071] In the initial release of 5G NR, PDCP duplication can be configured with up to two RLC entities for one radio bearer. Each PDCP PDU is duplicated with one copy mapped to the primary logical channel and one copy to the associated logical channel. Since each logical channel has its own RLC entity, there will be two RLC entities associated with the same radio bearer. MAC control elements (MAC CE) can be used to enable / disable PDCP duplication.

[0072] The framework was extended to support up to four RLC entities (carrier aggregation (CA) and dual connectivity (DC) based duplication). Reference is made to FIG. 2 and FIG. 3. FIG. 2 illustrates a schematic diagram of PDCP duplication supporting up to four RLC entities from a transmitter perspective, and FIG. 3 illustrates a schematic diagram of PDCP duplication supporting up to four RLC entities from receiver perspective. Thus, simultaneous duplication across carriers and sites can be handled, unlike earlier releases where either carrier aggregation or dual connectivity could be used in the uplink but not simultaneously. The enhanced PDCP duplication can be activated / deactivated by MAC control elements like earlier release. As shown in FIG. 2, at transmitter perspective, the packet with the same PDCP SN is copied to a plurality of RLC entities including RLC 1, RLC 2, RLC 3, and RLC 4. As shown in FIG. 3, at receiver perspective, when the PDCP entity receives the packet with the same PDCP SN from multiple RLC entities, there may be lot of duplicate packets which are discarded by PDCP entity.

[0073] When PDCP duplication is configured and activated, each of the associated RLC entities works independently. As all the associated RLC entities work independently, the status reporting, retransmission and reassembly are performed independently. In this case, when PDCP duplication is enabled or activated, there are different problems as detailed below.

[0074] On the one hand, radio resources wastage may be caused due to unnecessary transmission or retransmission. When PDCP duplication is configured, multiple RLC entities operate independently leading to quite many redundant RLC packet transmissionsor retransmissions even after the PDCP entity has received the packet successfully. This leads to waste of radio resources and bandwidth. For example, when a segment or complete RLC PDU is successfully received from one of the RLC entities (primary or associated) and the same segment or complete PDU is missed or not yet received from other RLC entities, then there is no need by the receiver to request its transmission peer for transmission or retransmission of the same RLC segment using RLC ARQ mechanism (as the same packet is received via other RLC entity).

[0075] On the other hand, increased latency in transferring packet to higher layers may be caused due to completely independent operation of RLC entities. When PDCP duplication is enabled, the primary and the associated RLC entities work independently to re-assemble the segmented RLC service data units (SDUs). There is possibility that individual RLC entity may not be able to form and send the re-assembled complete RLC SDU to PDCP due to missing segments, due to scheduling by gNB, packet lost, poor signaling conditions, congestion, errors, and the like. In this case, all RLC entities together may re-assemble the complete RLC SDU. Therefore, the current behavior of independent working of RLC entities results in delay in re-assembly to form the complete RLC SDU and sending the packets to the PDCP entity, which is not ideal for latency critical applications. With the possibility of enabling the re-assembly of RLC packet using the segments from primary RLC entity and the associated RLC entities together, the latency of the packet can be reduced. For example, when only the first half of the segment is successfully received from the first primary RLC entity and only the remaining half of the segment of the same duplicated RLC SDU is received from the associated RLC entity, it means that none of the RLC entity may form the complete RLC SDU since it waits for the remaining packet segments on the respective RLC entity. This results in delay in assembling the complete RLC SDU and sending it to the PDCP entity. In this case, increased latency is caused since each RLC entity needs to wait until RLC ARQ retransmission window expires.

[0076] In accordance with some example embodiments of the present disclosure, there is provided a solution for enhanced PDCP duplication procedure. In particular, the first apparatus determines that a packet from a PDCP entity of the first apparatus is to be duplicated on a plurality of RLC entities of the first apparatus. The duplicated PDCP packets across a plurality of RLC entities of the first apparatus obtain a common RLC SN, for example, assigned by linked RLC entity or PDCP entity, or determined by the RLCentity itself. The first apparatus transmits the duplicated PDCP packets with the common RLC SN to a second apparatus. Then the second apparatus re-assemble an RLC data unit after receiving the duplicated PDCP packets. With the enhanced PDCP duplication provided by the present disclosure, the redundancies in transmission or retransmission and the redundancies re-assembly of RLC packets can be reduced. In this case, the usage of radio resources can be optimized and the latency of transmission to packet to higher layer can be reduced.

[0077] Example embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. It is noted that the following accompanying drawings may be implemented separately or in any suitable combination, which is not limited in the present disclosure.

[0078] FIG. 4 illustrates an example signaling flow 400 of enhanced PDCP duplication according to some example embodiments of the present disclosure. For the purpose of discussion, the signaling flow 400 will be described with reference to FIG. 1, for example, by using the first apparatus 110 and the second apparatus 120. In some example embodiments, the first apparatus 110 may be a transmitter. In some example embodiments, the second apparatus may be a receiver. For example, the first apparatus 110 may be a terminal device, such as UE, and the second apparatus 120 may be a network device, such as a base station. Alternatively, the first apparatus 110 may be a network device and the second apparatus may be a terminal device. In the following descriptions, the linked RLC entity may refer to a new entity or an abstract layer which is similar to RLC protocol but may handle packets from multiple underlying RLC entities together. In some example embodiments, the linked RLC entity may refer to an RLC aggregator entity. In some example embodiments, the functionality of the logical linked RLC entity may be kept in PDCP layer.

[0079] The first apparatus 110 determines (4010) that a packet from a PDCP entity of the first apparatus 110 is to be duplicated on a plurality of RLC entities of the first apparatus 110.

[0080] In some example embodiments, the first apparatus 110 may indicate (4015) to the second apparatus 120 via a capability reporting, that an assignment of the common RLC SN for the duplicated PDCP packets is supported by the first apparatus 110. For example, the first apparatus 110 may report its support for enhanced PDCP duplication (i.e.coordination of RLC entities when duplication is activated) via UE capability reporting or some other form of reporting. For example, the enhanced PDCP duplication may be achieved by at least one linked RLC entity introduced between the PDCP layer and the RLC layer. Alternatively, the at least one linked RLC entity may be a function provided by either the PDCP layer or the RLC layer.

[0081] In some example embodiments, in a case where at least one linked RLC entity is introduced between the PDCP layer and the RLC layer at both the first apparatus 110 (e.g., a transmitter) and the second apparatus 120 (e.g., a receiver), if an indication received from the first apparatus 110 indicating that an enhanced PDCP duplication is activated at the first apparatus 110, the second apparatus 120 may activate (4020) the at least one linked RLC entity of the second apparatus 120. In other words, if enhanced PDCP duplication is activated, the linked RLC entity may also be activated at the second apparatus 120 by mapping with the RLC entities indicated as activated in the RLC activation or deactivation MAC CE for the corresponding cell group.

[0082] The first apparatus 110 assigns (4025), based on the determination by at least one linked RLC entity, duplicated PDCP packets across a plurality of RLC entities of the first apparatus 110 with a common RLC SN.

[0083] In some example embodiments, if the enhanced PDCP duplication is enabled, the first apparatus 110 may ensure that the RLC SN assigned to the duplicated PDCP packet is the same across the primary and the associated RLC entities. In some other example embodiments, PDCP PDU may be processed by the at least one linked RLC entity which is responsible for coordination of the RLC entities. In addition, the at least one linked RLC entity may handle the RLC SN assignment for the RLC SDU (i.e., PDCP PDU) and handling of transmitter window. In some other example embodiments, to enable the continuous RLC SN assignment on the primary RLC entity, the associated RLC entity, which is to carry the duplicated packet only (if PDCP duplication is enabled), may begin assigning the RLC SN from any valid number within the valid RLC SN range.

[0084] In some example embodiments, the at least one linked RLC entity of the first apparatus 110 along with the RLC SN assignment may perform processing of the RLC status report for all the mapped RLC entities, Tx window operations. In this case, the primary and the associated RLC entities may offload these procedures. In some example embodiments, if the RLC PDU is formed and received by the primary and associated RLCentities, the RLC PDU may be transparently forward to the corresponding mapped logical channel.

[0085] Details of the arrangement of at least one linked RLC entity from a transmitter perspective will be further discussed with reference to FIGS. 5-6.

[0086] In some example embodiments, at the first apparatus 110, the at least one linked RLC entity may be operated between the PDCP entity (i.e., the PDCP layer) and the plurality of RLC entities (i.e., the RLC layer). Alternatively, the at least one linked RLC may be a function provided by either the PDCP entity (i.e., the PDCP layer) or the plurality of RLC entities (i.e., the RLC layer)

[0087] FIG. 5 illustrates a schematic diagram of a PDCP duplication with separate linked RLC entities for MCG and SCG from transmitter perspective, according to some example embodiments of the present disclosure, and FIG. 6 illustrates a schematic diagram of a PDCP duplication with a common linked RLC entity across MCG and SCG from transmitter perspective, according to some example embodiments of the present disclosure.

[0088] In some example embodiments, at the first apparatus 110, the at least one linked RLC entity may include a first linked RLC entity and a second linked RLC entity. In some example embodiments, a first portion of RLC entities of a first cell group may be associated with the first linked RLC entity and a second portion of RLC entities of a second cell group may be associated with the second linked RLC entity. For example, as shown in FIG. 5, the first linked RLC entity may be linked RLC entity 510 and the second linked RLC entity may be linked RLC entity 520, and RLC#1 and RLC#2 are associated with the linked RLC entity 510, while RLC#3 and RLC#4 are associated with the linked RLC entity 520.

[0089] For example, as shown in FIG. 5, a linked RLC entity 510 for MCG is between the PDCP entity and the plurality of RLC entities including RLC#1 and RLC#2, and a linked RLC entity 520 for SCG is operated between the PDCP entity and the plurality of RLC entities including RLC#3 and RLC#4. In this case, the linked RLC entity 510 and the linked RLC entity 520 may assign RLC SN for the same duplicated packet and shares with all the associated RLC entities including RLC#1, RLC#2, RLC#3, and RLC#4.

[0090] In some other example embodiments, at the first apparatus 110, the at least one linked RLC entity may include a common linked RLC entity. In some exampleembodiments, the plurality of RLC entities of a plurality of cell groups is associated with the common linked RLC entity. For example, as shown in FIG. 6, the common linked RLC entity may be linked RLC entity 610, and the plurality of RLC entities of the plurality of cell groups including RLC#1, RLC#2, RLC#3, and RLC#4 are associated with the linked RLC entity 610.

[0091] Alternatively, as shown in FIG. 6, a linked RLC entity 610 for both MCG and SCG is operated between the PDCP entity and the plurality of RLC entities including RLC#1, RLC#2, RLC#3, and RLC#4. In this case, the linked RLC entity 610 may assign RLC SN for the same duplicated packet and shares with all the associated RLC entities including RLC#1, RLC#2, RLC#3, and RLC#4. In some example embodiments, the linked RLC entity may allocate the common RLC SN to the duplicated packet sent via multiple RLC entities, transmitter window operation and retransmission procedure.

[0092] In some example embodiments, the first apparatus 110 may indicate (4030) as in FIG. 4, to the second apparatus 120 via layer 2 (L2) signalling that a PDCP duplication may be activated at the first apparatus 110. As an example, the first apparatus 110 may indicate (4030) to the second apparatus 120 via MAC CE that a PDCP duplication is activated at the first apparatus 110. For example, referring to FIG. 9, which illustrates a schematic diagram of duplication RLC activation or deactivation MAC CE according to some example embodiments of the present disclosure. As shown in FIG. 9, each of the RLCo, RLCi, and RLC2 represents the associated RLC entity for duplication.

[0093] In some example embodiments, a data radio bearer (DRB) may be indicated in the MAC CE. In this case, when DRB is configured for enhanced PDCP duplication procedure, the linked RLC entity may also be activated at the transmitter, which is mapped to the primary and all the activated associated RLC entities for duplication. For example, when a DRB is configured for PDCP duplication, the second apparatus 120 may also configure enhanced PDCP duplication (i.e. coordination of RLC entities) based on the UE capability. In some other example embodiments, if the MAC CE indicates that an associated RLC entity is deactivated, the corresponding mapping may be removed from the linked RLC entity.

[0094] Referring back to FIG. 4, the first apparatus 110 transmits (4035) the duplicated PDCP packets with the common RLC SN to the second apparatus 120. In other words, the second apparatus 120 receives (4035), at a plurality of RLC entities of the secondapparatus 120, duplicated PDCP packets from the first apparatus 110. The second apparatus causes (4040) the duplicated PDCP packets to be delivered from the plurality of RLC entities to at least one linked RLC entity of the second apparatus 120.

[0095] In other words, the RLC PDUs received from the primary and the associated RLC entities by the respective RLC entities may be forwarded to the linked RLC entity for reassembly. In addition, duplicate packet detection, re-assembly, receiver window operation, and RLC status reporting may be performed by the linked RLC entity, and the RLC SDU may be sent to higher layers.

[0096] Details of the arrangement of at least one linked RLC entity from receiver perspective will be further discussed with reference to FIGS. 7-8.

[0097] In some example embodiments, at the second apparatus 120, the at least one linked RLC entity may be operated between the PDCP entity (i.e., the PDCP layer) and the plurality of RLC entities (i.e., the RLC layer). Alternatively, the at least one linked RLC may be a function provided by either the PDCP entity (i.e., the PDCP layer) or the plurality of RLC entities (i.e., the RLC layer)

[0098] FIG. 7 illustrates a schematic diagram of a PDCP duplication with common linked RLC entity across MCG and SCG from receiver perspective, according to some example embodiments of the present disclosure, and FIG. 8 illustrates a schematic diagram of a PDCP duplication with separate linked RLC entity for MCG and SCG from receiver perspective, according to some example embodiments of the present disclosure.

[0099] For example, as shown in FIG. 7, a linked RLC entity 710 for both MCG and SCG is between the PDCP entity and the plurality of RLC entities including RLC#1, RLC#2, RLC#3, and RLC#4.

[0100] Alternatively, as shown in FIG. 8, a linked RLC entity 810 for MCG is between the PDCP entity and the plurality of RLC entities including RLC#1 and RLC#2, and a linked RLC entity 820 for SCG is between the PDCP entity and the plurality of RLC entities including RLC#3 and RLC#4.

[0101] In some example embodiments, the linked RLC entity may be used to enable reassembly of RLC packets using RLC segments from multiple RLC entities. In some other example embodiments, the linked RLC entity may be used to handle receiver window operations and RLC status reporting.

[0102] In some example embodiments, at the second apparatus 120, the at least one linked RLC entity may include a common linked RLC entity. In some example embodiments, the plurality of RLC entities of a plurality of cell groups is associated with the common linked RLC entity. For example, as shown in FIG. 7, the common linked RLC entity may be linked RLC entity 710, and the plurality of RLC entities of the plurality of cell groups including RLC#1, RLC#2, RLC#3, and RLC#4 are associated with the linked RLC entity 710. In some example embodiments, the common linked RLC entity may be more suitable in cases where PDCP and RLC are together, for example, at UE side. In addition, the common linked RLC entity may be benefit in assembling the RLC SDU from maximum number of associated RLC entities.

[0103] In some example embodiments, at the second apparatus 120, the at least one linked RLC entity may include a first linked RLC entity and a second linked RLC entity. In some example embodiments, a first portion of RLC entities of a first cell group may be associated with the first linked RLC entity and a second portion of RLC entities of a second cell group may be associated with the second linked RLC entity. For example, as shown in FIG. 8, the first linked RLC entity may be linked RLC entity 810 and the second linked RLC entity may be linked RLC entity 820, and RLC#1 and RLC#2 are associated with the linked RLC entity 810, while RLC#3 and RLC#4 are associated with the linked RLC entity 820. In some example embodiments, the separate linked RLC entity may be suitable for any kind of deployment, in UL or DL. In some example embodiments, the reassembly may be limited to the MCG or the SCG.

[0104] As described above, if the duplicated PDCP packets are assigned with a common RLC SN, the second apparatus 120 re-assembles (4045) as in FIG. 4, by the at least one linked RLC entity, an RLC data unit based on at least one duplicated PDCP packet of the duplicated PDCP packets. In other words, if the enhanced PDCP duplication is enabled, re-assembly may be done commonly across the primary and the associated RLC entity, which is enabled by the same RLC SN being assigned to the duplicated packet at the first apparatus 110.

[0105] In some example embodiments, if the RLC data unit is completely re-assembled based on a duplicated PDCP packet from a first RLC entity in the plurality of RLC entities, the second apparatus 120 may discard duplicated PDCP packets from other RLC entities in the plurality of RLC entities. In other words, if a duplicate RLC PDU is received, itmay be discarded by the Linked RLC entity.

[0106] In some example embodiments, if the RLC data unit is not completely reassembled based on a duplicated PDCP packet from a first RLC entity in the plurality of RLC entities, the second apparatus 120 may determine whether a lacking portion of the RLC data unit is obtainable from one or more other RLC entities in the plurality of RLC entities. In addition, if the lacking portion of the RLC data unit is obtainable, the second apparatus 120 may re-assemble (4045) the RLC data unit based on the duplicated PDCP packet from the first RLC entity and duplicated PDCP packets from the one or more other RLC entities.

[0107] In some example embodiments, if an RLC status report is triggered, the second apparatus 120 may retrieve a status of a receiver window from the at least one linked RLC entity. In addition, the second apparatus 120 may generate the RLC status report based on the retrieved status within the receiver window. In some example embodiments, the RLC status report may be limited to the highest SN received from the plurality of RLC entities. In other words, if the primary or the associated RLC entity triggers the status report, the status of the receiver window may be retrieved from the linked RLC entity, and the status report may be transmitted to the first apparatus 110. In addition, the status report may be limited to the highest SN received by the triggered RLC entity, for example, ACK_SN field limited to the highest SN received by this RLC entity.

[0108] In some example embodiments, if the RLC data unit is completely re-assembled based on at least one duplicated PDCP packet in the duplicated PDCP packets assigned with the common RLC SN, the second apparatus 120 may indicate (4050) as in FIG. 4, in the RLC status report, an acknowledgement (ACK) for the duplicated PDCP packets. For example, if the complete or segmented SN is successfully received by at least one RLC entity, ACK may be transmitted for complete or segmented SN for all the primary and the associated RLC entities.

[0109] In some other example embodiments, if no duplicated PDCP packet in the duplicated PDCP packets is available for re-assembling the RLC data unit individually, the second apparatus 120 may indicate (4050) as in FIG. 4, in the RLC status report, a non-acknowledgement (NACK) for the duplicated PDCP packets. For example, if the part of the SN or complete SN is not received by any of the RLC entity, NACK may be transmitted to all the primary and the associated RLC entities.

[0110] After the RLC data unit is completely re-assembled, the second apparatus 120 causes (4055), as in FIG. 4, the reassembled RLC data unit to be sent to a PDCP entity of the second apparatus 120. In other words, if the complete RLC SDU is formed after reassembly, the RLC SDU is transmitted to the PDCP entity.[OHl] In some example embodiments, an individual RLC entities may not achieve the complete SDU, but the linked RLC entity may achieve the complete SDU, and an example is shown referring to FIG. 10 and FIG. 11. FIG. 10 illustrates a schematic diagram of an example scenario of RLC packet data unit (PDU) with SN according to some example embodiments of the present disclosure, FIG. 11 illustrates a schematic diagram of reassembling a segmented PDU from associated RLC entities according to some example embodiments of the present disclosure. As shown in FIG. 10, a RLC SDU with SN: 0 of size 100 bytes is duplicated and transmitted in all the RLC entities. As for a first RLC entity 1010, only 0 to 50 bytes are received; as for a second RLC entity 1020, only 60 to 100 bytes are received; and for a third RLC entity 1030, 0 to 70 bytes are received. Referring to FIG. 11, none of the first RLC entity 1010 (primary RLC entity) and the second RLC entity 1020 (associated RLC entity) may assemble the complete RLC SDU. However, the linked RLC entity 1110 may assemble the complete RLC SDU 1120. The assembled complete RLC SDU 1120 is formed from the segments received from all associated RLC entities in the linked RLC entity 1110.

[0112] FIG. 12 illustrates another example signaling flow 1200 of enhanced PDCP duplication according to some example embodiments of the present disclosure. In this case, PDCP may itself have the RLC SN assigned and share to associated RLC entities. For the purpose of discussion, the signaling flow 1200 will be described with reference to FIG. 1, for example, by using the first apparatus 110 and the second apparatus 120. In some example embodiments, the first apparatus 110 may be a transmitter. In some example embodiments, the second apparatus may be a receiver. For example, the first apparatus 110 may be a terminal device, such as UE, and the second apparatus 120 may be a network device, such as a base station. Alternatively, the first apparatus 110 may be a network device and the second apparatus may be a terminal device. In the following descriptions, the linked RLC entity may refer to a new entity or an abstract layer which is similar as RLC protocol but may handle packets from multiple underlying RLC entities together. In some example embodiments, the linked RLC entity may refer to an RLC aggregator entity.

[0113] The first apparatus 110 determines (12010) that a packet from a PDCP entity of the first apparatus 110 is to be duplicated on a plurality of RLC entities of the first apparatus 110. In some example embodiments, the first apparatus 110 may indicate (12015), to the second apparatus 120 via MAC CE, that a PDCP duplication is activated at the first apparatus 110. As an example, the first apparatus 110 may indicate (12015) to the second apparatus 120 via MAC CE that a PDCP duplication is activated at the first apparatus 110. In some example embodiments, a DRB is indicated in the MAC CE. In some example embodiments, if an indication received from the first apparatus 110 indicates that a PDCP duplication is activated at the first apparatus 110, the second apparatus 120 may activate the data re-assembly at the PDCP entity.

[0114] The first apparatus 110 assigns (12020), by the PDCP entity based on the determination, duplicated PDCP packets across a plurality of RLC entities of the first apparatus 110 with a common RLC SN. In some example embodiments, the first apparatus 110 may indicate (12025), to the second apparatus 120 via a capability reporting, that an assignment of the common RLC SN for the duplicated PDCP packets is supported by the first apparatus 110.

[0115] The first apparatus 110 transmits (12030) the duplicated PDCP packets with the common RLC SN to a second apparatus 120. In other words, the second apparatus 120 receives (12030), at a plurality of RLC entities of the second apparatus 120, duplicated PDCP packets from a first apparatus 110. If the duplicated PDCP packets are assigned with a common RLC SN, the second apparatus 120 re-assembles (12035), by a PDCP entity of the second apparatus 120, an RLC data unit based on at least one duplicated PDCP packet of the duplicated PDCP packets.

[0116] In some example embodiments, if the RLC data unit is completely re-assembled based on a duplicated PDCP packet from a first RLC entity in the plurality of RLC entities, the second apparatus 120 may discard duplicated PDCP packets from other RLC entities in the plurality of RLC entities.

[0117] In some example embodiments, if the RLC data unit is not completely reassembled based on a duplicated PDCP packet from a first RLC entity in the plurality of RLC entities, the second apparatus 120 may determine whether a lacking portion of the RLC data unit is obtainable from one or more other RLC entities in the plurality of RLC entities. In addition, if the lacking portion of the RLC data unit is obtainable, the secondapparatus 120 may re-assemble (12035) the RLC data unit based on the duplicated PDCP packet from the first RLC entity and duplicated PDCP packets from the one or more other RLC entities.

[0118] In some example embodiments, if an RLC status report is triggered, the second apparatus 120 may retrieve a status of a receiver window from the PDCP entity. In addition, the second apparatus 120 may generate the RLC status report based on the retrieved status within the receiver window. In some example embodiments, the RLC status report may be limited to the highest SN received from the plurality of RLC entities.

[0119] In some example embodiments, if the RLC data unit is completely re-assembled based on at least one duplicated PDCP packet in the duplicated PDCP packets assigned with the common RLC SN, the second apparatus 120 may indicate (12040), in the RLC status report, an acknowledgement for the duplicated PDCP packets. In some other example embodiments, if no duplicated PDCP packet in the duplicated PDCP packets is available for re-assembling the RLC data unit individually, the second apparatus 120 may indicate (12040), in the RLC status report, a non-acknowledgement for the duplicated PDCP packets.

[0120] FIG. 13 illustrates another example signaling flow 1300 of enhanced PDCP duplication according to some example embodiments of the present disclosure. In this case, associated RLC entity by itself may derive RLC SN based on PDCP SN, for example, first duplicated PDCP PDUs SN maps to RLC SN 0 and so on. For the purpose of discussion, the signaling flow 1300 will be described with reference to FIG. 1, for example, by using the first apparatus 110 and the second apparatus 120. In some example embodiments, the first apparatus 110 may be a transmitter. In some example embodiments, the second apparatus may be a receiver. For example, the first apparatus 110 may be a terminal device, such as UE, and the second apparatus 120 may be a network device, such as a base station. Alternatively, the first apparatus 110 may be a network device and the second apparatus may be a terminal device. In the following descriptions, the linked RLC entity may refer to a new entity or an abstract layer which is similar as RLC protocol but may handle packets from multiple underlying RLC entities together. In some example embodiments, the linked RLC entity may refer to an RLC aggregator entity.

[0121] The first apparatus 110 determines (13010) a mapping between RLC SNs and PDCP SNs. In some example embodiments the first apparatus 110 may indicate, to thesecond apparatus 120 via MAC CE that a PDCP duplication is activated at the first apparatus 110. For example, the first apparatus 110 may indicate to the second apparatus 120 via MAC CE that a PDCP duplication is activated at the first apparatus 110. In some example embodiments, a DRB may be indicated in the MAC CE. In some example embodiments, if an indication received from the first apparatus 110 indicates that a PDCP duplication is activated at the first apparatus 110, the second apparatus 120 may activate the data re-assembly at the PDCP entity.

[0122] If a packet from a PDCP entity of the first apparatus 110 is to be duplicated on a plurality of RLC entities of the first apparatus 110, the first apparatus 110 determines (13020), by a plurality of RLC entities, a same RLC SN of duplicated PDCP packets across the plurality of RLC entities based on the mapping and a PDCP SN of the duplicated PDCP packets.

[0123] The first apparatus 110 transmits (13030) the duplicated PDCP packets with the same RLC SN to a second apparatus 120. In other words, the second apparatus 120 receives (13030) duplicated PDCP packets from a first apparatus 110. If the duplicated PDCP packets are with a same RLC SN, the second apparatus 120 re-assembles (13035) an RLC data unit based on at least one duplicated PDCP packet of the duplicated PDCP packets.

[0124] In some example embodiments, if the RLC data unit is completely re-assembled based on a duplicated PDCP packet from a first RLC entity in the plurality of RLC entities, the second apparatus 120 may discard duplicated PDCP packets from other RLC entities in the plurality of RLC entities.

[0125] In some example embodiments, if the RLC data unit is not completely reassembled based on a duplicated PDCP packet from a first RLC entity in the plurality of RLC entities, the second apparatus 120 may determine whether a lacking portion of the RLC data unit is obtainable from one or more other RLC entities in the plurality of RLC entities. In addition, if the lacking portion of the RLC data unit is obtainable, the second apparatus may re-assemble (13035) the RLC data unit based on the duplicated PDCP packet from the first RLC entity and duplicated PDCP packets from the one or more other RLC entities.

[0126] In some example embodiments, if the RLC data unit is completely re-assembled based on at least one duplicated PDCP packet in the duplicated PDCP packets assignedwith the common RLC SN, the second apparatus 120 may indicate (13040), in the RLC status report, an acknowledgement for the duplicated PDCP packets. In some other example embodiments, if no duplicated PDCP packet in the duplicated PDCP packets is available for re-assembling the RLC data unit individually, the second apparatus 120 may indicate (13040), in the RLC status report, a non-acknowledgement for the duplicated PDCP packets.

[0127] FIG. 14 illustrates a flowchart of enhanced PDCP duplication from transmitter perspective according to some example embodiments of the present disclosure. For the purpose of discussion, the method 1400 will be described from the perspective of the first apparatus 110 in FIG. 1.

[0128] At block 1410, the first apparatus 110 receives a packet by PDCP from a higher layer. At block 1420, the first apparatus 110 determines whether enhanced PDCP duplication is enabled. If the enhanced PDCP duplication is not enabled, at block 1430, the first apparatus 110 sends the packet to the corresponding RLC entity. If the enhanced PDCP duplication is enabled, at block 1440, the first apparatus 110 sends the packet to the corresponding linked RLC entity. In addition, at block 1450, the first apparatus 110 assigns a SN and sends to each of primary and the associated RLC entities.

[0129] FIG. 15 illustrates a flowchart of enhanced PDCP duplication from receiver perspective according to some example embodiments of the present disclosure. For the purpose of discussion, the method 1500 will be described from the perspective of the second apparatus 120 in FIG. 1.

[0130] At block 1510, the second apparatus 120 receives the duplicated packet by associated RLC entity. At block 1520, the second apparatus 120 determines whether enhanced PDCP duplication is enabled. If the enhanced PDCP duplication is not enabled, at block 1530, the second apparatus 120 sends the packet to the corresponding PDCP entity. If the PDCP duplication is enabled, at block 1540, the second apparatus 120 sends the packet to the corresponding linked RLC entity. In addition, at block 1550, the second apparatus 120 performs reassembly of segment received from multiple associated RLC entity and sends the complete RLC SDU to PDCP.

[0131] With the foregoing embodiments, since the re-assembly of the RLC PDU may be done collectively for all the associated RLC entities, it is beneficial to faster processing of packets and sent to higher layer. Moreover, in cell coverage areas where interferenceis more or device in mobility state or in poor signaling coverage areas where RLC NACKs are more in some of the associated RLC entities, such associated RLC entities may be deactivated from the PDCP duplicated dynamically. In addition, the solution provided in the present disclosure is beneficial to avoid transmission or retransmission of packet, even if packet is received by at least one associated RLC entity. In this case, radio resources are saved. Furthermore, it is easier to detect infringement and easy to implement when sending unique segments for a packet to each of the associated RLC entities. For example, it may verify if complete PDU can be assembled and sent to higher layer, PDCP, and it may verify the status report if the packet is ACK’ed. In addition, as the linked RLC entity is aware of the packet data rate, ACK, NACK or the like, for each of the associated RLC entity, an artificial machine learning (AIML) model may be used in linked RLC entity to monitor the data rate, ACK / NACK pattern etc., which may be used to detect the redundant or need for additional RLC entity based on which some of the associated RLC entities may be activated or deactivated dynamically.

[0132] FIG. 16 shows a flowchart of an example method 1600 implemented at a first apparatus in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 1600 will be described from the perspective of the first apparatus 110 in FIG. 1.

[0133] At block 1610, the first apparatus determines that a packet from a PDCP entity of the first apparatus is to be duplicated on a plurality of RLC entities of the first apparatus.

[0134] At block 1620, the first apparatus assigns, based on the determination by at least one linked RLC entity, duplicated PDCP packets across a plurality of RLC entities of the first apparatus with a common RLC SN.

[0135] At block 1630, the first apparatus transmits the duplicated PDCP packets with the common RLC SN to a second apparatus.

[0136] In some example embodiments, the at least one linked RLC entity is operated between the PDCP entity and the plurality of RLC entities or as a function provided by either the PDCP entity or the plurality of RLC entities.

[0137] In some example embodiments, the at least one linked RLC entity comprises a common linked RLC entity, and wherein the plurality of RLC entities of a plurality of cell groups is associated with the common linked RLC entity.

[0138] In some example embodiments, the at least one linked RLC entity comprises a first linked RLC entity and a second linked RLC entity. In some example embodiments, a first portion of RLC entities of a first cell group is associated with the first linked RLC entity and a second portion of RLC entities of a second cell group is associated with the second linked RLC entity.

[0139] In some example embodiments, the method 1600 further comprises: indicating, to the second apparatus via a capability reporting, that an assignment of the common RLC SN for the duplicated PDCP packets is supported by the first apparatus.

[0140] In some example embodiments, the method 1600 further comprises: indicating, to the second apparatus via layer 2, L2, signalling that a PDCP duplication is activated at the first apparatus. In some example embodiments, the L2 signalling comprises medium access control elements, MAC CE.

[0141] In some example embodiments, a data radio bearer, DRB, is indicated in the MAC CE.

[0142] In some example embodiments, the first apparatus comprises a transmitter and the second apparatus comprises a receiver.

[0143] FIG. 17 shows a flowchart of an example method 1700 implemented at a second apparatus in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 1700 will be described from the perspective of the second apparatus 120 in FIG. 1.

[0144] At block 1710, the second apparatus 120 receives, at a plurality of RLC entities of the second apparatus, duplicated PDCP packets from a first apparatus.

[0145] At block 1720, the second apparatus 120 causes the duplicated PDCP packets to be delivered from the plurality of RLC entities to at least one linked RLC entity of the second apparatus.

[0146] At block 1730, in accordance with a determination that the duplicated PDCP packets are assigned with a common RLC SN, the second apparatus 120 re-assembles by the at least one linked RLC entity, an RLC data unit based on at least one duplicated PDCP packet of the duplicated PDCP packets.

[0147] At block 1740, the second apparatus 120 causes the reassembled RLC data unitto be sent to a PDCP entity of the second apparatus.

[0148] In some example embodiments, the method 1700 further comprises: in accordance with a determination that an indication received from the first apparatus indicating that a PDCP duplication is activated at the first apparatus, activating the at least one linked RLC entity of the second apparatus.

[0149] In some example embodiments, the method 1700 further comprises: in accordance with a determination that the RLC data unit is completely re-assembled based on a duplicated PDCP packet from a first RLC entity in the plurality of RLC entities, discarding duplicated PDCP packets from other RLC entities in the plurality of RLC entities.

[0150] In some example embodiments, the method 1700 further comprises: in accordance with a determination that the RLC data unit is not completely re-assembled based on a duplicated PDCP packet from a first RLC entity in the plurality of RLC entities, determining whether a lacking portion of the RLC data unit is obtainable from one or more other RLC entities in the plurality of RLC entities; and in accordance with a determination that the lacking portion of the RLC data unit is obtainable, re-assembling the RLC data unit based on the duplicated PDCP packet from the first RLC entity and duplicated PDCP packets from the one or more other RLC entities.

[0151] In some example embodiments, the method 1700 further comprises: in accordance with a determination that an RLC status report is triggered, retrieving a status of a receiver window from the at least one linked RLC entity; and generating the RLC status report based on the retrieved status within the receiver window.

[0152] In some example embodiments, the method 1700 further comprises: in accordance with a determination that the RLC data unit is completely re-assembled based on at least one duplicated PDCP packet in the duplicated PDCP packets assigned with the common RLC SN, indicating in the RLC status report, an acknowledgement for the duplicated PDCP packets.

[0153] In some example embodiments, the method 1700 further comprises: in accordance with a determination that no duplicated PDCP packet in the duplicated PDCP packets is available for re-assembling the RLC data unit individually, indicating in the RLC status report, a non-acknowledgement for the duplicated PDCP packets.

[0154] In some example embodiments, the RLC status report is limited to the highest SNreceived from the plurality of RLC entities.

[0155] In some example embodiments, the at least one linked RLC entity is operated between the PDCP entity and the plurality of RLC entities or as a function provided by either the PDCP entity or the plurality of RLC entities.

[0156] In some example embodiments, the at least one linked RLC entity comprises a common linked RLC entity, and wherein the plurality of RLC entities of a plurality of cell groups is associated with the common linked RLC entity.

[0157] In some example embodiments, the at least one linked RLC entity comprises a first linked RLC entity and a second linked RLC entity. In some example embodiments, a first portion of RLC entities of a first cell group is associated with the first linked RLC entity and a second portion of RLC entities of a second cell group is associated with the second linked RLC entity.

[0158] In some example embodiments, the first apparatus comprises a transmitter and the second apparatus comprises a receiver.

[0159] FIG. 18 shows a flowchart of an example method 1800 implemented at a first apparatus in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 1800 will be described from the perspective of the first apparatus 110 in FIG. 1.

[0160] At block 1810, the first apparatus 110 determines that a packet from a PDCP entity of the first apparatus is to be duplicated on a plurality of RLC entities of the first apparatus.

[0161] At block 1820, the first apparatus 110 assigns, by the PDCP entity based on the determination, duplicated PDCP packets across a plurality of RLC entities of the first apparatus with a common RLC SN.

[0162] At block 1830, the first apparatus 110 transmits the duplicated PDCP packets with the common RLC SN to a second apparatus.

[0163] In some example embodiments, the method 1800 further comprises: indicating, to the second apparatus via a capability reporting, that an assignment of the common RLC SN for the duplicated PDCP packets is supported by the first apparatus.

[0164] In some example embodiments, the method 1800 further comprises: indicating,to the second apparatus via lay 2, L2, signalling that a PDCP duplication is activated at the first apparatus. In some example embodiments, the L2 signalling comprises medium access control control elements, MAC CE.

[0165] In some example embodiments, a data radio bearer, DRB, is indicated in the MAC CE.

[0166] In some example embodiments, the first apparatus comprises a transmitter and the second apparatus comprises a receiver.

[0167] FIG. 19 shows a flowchart of an example method 1900 implemented at a second apparatus in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 1900 will be described from the perspective of the second apparatus 120 in FIG. 1.

[0168] At block 1910, the second apparatus receives, at a plurality of RLC entities of the second apparatus, duplicated PDCP packets from a first apparatus.

[0169] At block 1920, in accordance with a determination that the duplicated PDCP packets are assigned with a common RLC SN, the second apparatus re-assembles by a PDCP entity of the second apparatus, an RLC data unit based on at least one duplicated PDCP packet of the duplicated PDCP packets.

[0170] In some example embodiments, the method 1900 further comprises: in accordance with a determination that an indication received from the first apparatus indicating that a PDCP duplication is activated at the first apparatus, activating the data re-assembly at the PDCP entity.

[0171] In some example embodiments, the method 1900 further comprises: in accordance with a determination that the RLC data unit is completely re-assembled based on a duplicated PDCP packet from a first RLC entity in the plurality of RLC entities, discarding duplicated PDCP packets from other RLC entities in the plurality of RLC entities.

[0172] In some example embodiments, the method 1900 further comprises: in accordance with a determination that the RLC data unit is not completely re-assembled based on a duplicated PDCP packet from a first RLC entity in the plurality of RLC entities, determining whether a lacking portion of the RLC data unit is obtainable from one or more other RLC entities in the plurality of RLC entities; and in accordance with a determinationthat the lacking portion of the RLC data unit is obtainable, re-assembling the RLC data unit based on the duplicated PDCP packet from the first RLC entity and duplicated PDCP packets from the one or more other RLC entities.

[0173] In some example embodiments, the method 1900 further comprises: in accordance with a determination that an RLC status report is triggered, retrieving a status of a receiver window from the PDCP entity; and generating the RLC status report based on the retrieved status within the receiver window.

[0174] In some example embodiments, the method 1900 further comprises: in accordance with a determination that the RLC data unit is completely re-assembled based on at least one duplicated PDCP packet in the duplicated PDCP packets assigned with the common RLC SN, indicating in the RLC status report, an acknowledgement for the duplicated PDCP packets.

[0175] In some example embodiments, the method 1900 further comprises: in accordance with a determination that no duplicated PDCP packet in the duplicated PDCP packets is available for re-assembling the RLC data unit individually, indicating in the RLC status report, a non-acknowledgement for the duplicated PDCP packets.

[0176] In some example embodiments, the RLC status report is limited to the highest SN received from the plurality of RLC entities.

[0177] In some example embodiments, the first apparatus comprises a transmitter and the second apparatus comprises a receiver.

[0178] FIG. 20 shows a flowchart of an example method 2000 implemented at a first apparatus in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 2000 will be described from the perspective of the first apparatus 110 in FIG. 1.

[0179] At block 2010, the first apparatus determines a mapping between RLC SNs and PDCP SNs.

[0180] At block 2020, in accordance with a determination that a packet from a PDCP entity of the first apparatus is to be duplicated on a plurality of RLC entities of the first apparatus, the first apparatus determines by a plurality of RLC entities, a same RLC SN of duplicated PDCP packets across the plurality of RLC entities based on the mapping anda PDCP SN of the duplicated PDCP packets.

[0181] At block 2030, the first apparatus transmits the duplicated PDCP packets with the same RLC SN to a second apparatus.

[0182] In some example embodiments, the method 2000 further comprises: indicating, to the second apparatus via lay 2, L2, signalling that a PDCP duplication is activated at the first apparatus. In some example embodiments, the L2 signalling comprises medium access control control elements, MAC CE.

[0183] In some example embodiments, a data radio bearer, DRB, is indicated in the MAC CE.

[0184] In some example embodiments, the first apparatus comprises a transmitter and the second apparatus comprises a receiver.

[0185] FIG. 21 shows a flowchart of an example method 2100 implemented at a second apparatus in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 2100 will be described from the perspective of the second apparatus 120 in FIG. 1.

[0186] At block 2110, the second apparatus 120 receives duplicated PDCP packets from a first apparatus.

[0187] At block 2120, in accordance with a determination that the duplicated PDCP packets are with a same RLC SN, the second apparatus 120 re-assembles an RLC data unit based on at least one duplicated PDCP packet of the duplicated PDCP packets.

[0188] In some example embodiments, the method 2100 further comprises: in accordance with a determination that an indication received from the first apparatus indicating that a PDCP duplication is activated at the first apparatus, activating the data re-assembly at the PDCP entity.

[0189] In some example embodiments, the method 2100 further comprises: in accordance with a determination that the RLC data unit is completely re-assembled based on a duplicated PDCP packet from a first RLC entity in the plurality of RLC entities, discarding duplicated PDCP packets from other RLC entities in the plurality of RLC entities.

[0190] In some example embodiments, the method 2100 further comprises: in accordance with a determination that the RLC data unit is not completely re-assembled based on aduplicated PDCP packet from a first RLC entity in the plurality of RLC entities, determining whether a lacking portion of the RLC data unit is obtainable from one or more other RLC entities in the plurality of RLC entities; and in accordance with a determination that the lacking portion of the RLC data unit is obtainable, re-assembling the RLC data unit based on the duplicated PDCP packet from the first RLC entity and duplicated PDCP packets from the one or more other RLC entities.

[0191] In some example embodiments, the method 2100 further comprises: in accordance with a determination that the RLC data unit is completely re-assembled based on at least one duplicated PDCP packet in the duplicated PDCP packets assigned with the common RLC SN, indicating in the RLC status report, an acknowledgement for the duplicated PDCP packets.

[0192] In some example embodiments, the method 2100 further comprises: in accordance with a determination that no duplicated PDCP packet in the duplicated PDCP packets is available for re-assembling the RLC data unit individually, indicating in the RLC status report, a non-acknowledgement for the duplicated PDCP packets.

[0193] In some example embodiments, the first apparatus comprises a transmitter and the second apparatus comprises a receiver.

[0194] In some example embodiments, a first apparatus capable of performing any of the method 1600 (for example, the first apparatus 110 in FIG. 1) may comprise means for performing the respective operations of the method 1600. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The first apparatus may be implemented as or included in the first apparatus 110 in FIG. 1.

[0195] In some example embodiments, the first apparatus comprises means for determining that a packet from a PDCP entity of the first apparatus is to be duplicated on a plurality of RLC entities of the first apparatus; means for assigning, based on the determination by at least one linked RLC entity, duplicated PDCP packets across a plurality of RLC entities of the first apparatus with a common RLC SN; and means for transmitting the duplicated PDCP packets with the common RLC SN to a second apparatus.

[0196] In some example embodiments, the at least one linked RLC entity is operated between the PDCP entity and the plurality of RLC entities or as a function provided byeither the PDCP entity or the plurality of RLC entities.

[0197] In some example embodiments, the at least one linked RLC entity comprises a common linked RLC entity, and wherein the plurality of RLC entities of a plurality of cell groups is associated with the common linked RLC entity.

[0198] In some example embodiments, the at least one linked RLC entity comprises a first linked RLC entity and a second linked RLC entity, and wherein a first portion of RLC entities of a first cell group is associated with the first linked RLC entity and a second portion of RLC entities of a second cell group is associated with the second linked RLC entity.

[0199] In some example embodiments, the first apparatus further comprises: means for indicating, to the second apparatus via a capability reporting, that an assignment of the common RLC SN for the duplicated PDCP packets is supported by the first apparatus.

[0200] In some example embodiments, the first apparatus further comprises: means for indicating, to the second apparatus via layer 2, L2, signalling that a PDCP duplication is activated at the first apparatus. In some example embodiments, the L2 signalling comprises medium access control control elements, MAC CE.

[0201] In some example embodiments, a data radio bearer, DRB, is indicated in the MAC CE.

[0202] In some example embodiments, the first apparatus comprises a transmitter and the second apparatus comprises a receiver.

[0203] In some example embodiments, a second apparatus capable of performing any of the method 1700 (for example, the second apparatus 120 in FIG. 1) may comprise means for performing the respective operations of the method 1700. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The second apparatus may be implemented as or included in the second apparatus 120 in FIG. 1.

[0204] In some example embodiments, the second apparatus comprises means for receiving, at a plurality of RLC entities of the second apparatus, duplicated PDCP packets from a first apparatus; means for causing the duplicated PDCP packets to be delivered from the plurality of RLC entities to at least one linked RLC entity of the second apparatus;means for in accordance with a determination that the duplicated PDCP packets are assigned with a common RLC SN, re-assembling by the at least one linked RLC entity, an RLC data unit based on at least one duplicated PDCP packet of the duplicated PDCP packets; and means for causing the reassembled RLC data unit to be sent to a PDCP entity of the second apparatus.

[0205] In some example embodiments, the second apparatus further comprises: means for in accordance with a determination that an indication received from the first apparatus indicating that a PDCP duplication is activated at the first apparatus, activating the at least one linked RLC entity of the second apparatus.

[0206] In some example embodiments, the second apparatus further comprises: means for in accordance with a determination that the RLC data unit is completely re-assembled based on a duplicated PDCP packet from a first RLC entity in the plurality of RLC entities, discarding duplicated PDCP packets from other RLC entities in the plurality of RLC entities.

[0207] In some example embodiments, the second apparatus further comprises: means for in accordance with a determination that the RLC data unit is not completely reassembled based on a duplicated PDCP packet from a first RLC entity in the plurality of RLC entities, determining whether a lacking portion of the RLC data unit is obtainable from one or more other RLC entities in the plurality of RLC entities; and means for in accordance with a determination that the lacking portion of the RLC data unit is obtainable, re-assembling the RLC data unit based on the duplicated PDCP packet from the first RLC entity and duplicated PDCP packets from the one or more other RLC entities.

[0208] In some example embodiments, the second apparatus further comprises: means for in accordance with a determination that an RLC status report is triggered, retrieving a status of a receiver window from the at least one linked RLC entity; and means for generating the RLC status report based on the retrieved status within the receiver window.

[0209] In some example embodiments, the second apparatus further comprises: means for in accordance with a determination that the RLC data unit is completely re-assembled based on at least one duplicated PDCP packet in the duplicated PDCP packets assigned with the common RLC SN, indicating in the RLC status report, an acknowledgement for the duplicated PDCP packets.

[0210] In some example embodiments, the second apparatus further comprises: means for in accordance with a determination that no duplicated PDCP packet in the duplicated PDCP packets is available for re-assembling the RLC data unit individually, indicating in the RLC status report, a non-acknowledgement for the duplicated PDCP packets.

[0211] In some example embodiments, the RLC status report is limited to the highest SN received from the plurality of RLC entities.

[0212] In some example embodiments, the at least one linked RLC entity is operated between the PDCP entity and the plurality of RLC entities or as a function provided by either the PDCP entity or the plurality of RLC entities.

[0213] In some example embodiments, the at least one linked RLC entity comprises a common linked RLC entity, and wherein the plurality of RLC entities of a plurality of cell groups is associated with the common linked RLC entity.

[0214] In some example embodiments, the at least one linked RLC entity comprises a first linked RLC entity and a second linked RLC entity, and wherein a first portion of RLC entities of a first cell group is associated with the first linked RLC entity and a second portion of RLC entities of a second cell group is associated with the second linked RLC entity.

[0215] In some example embodiments, the first apparatus comprises a transmitter and the second apparatus comprises a receiver.

[0216] In some example embodiments, a first apparatus capable of performing any of the method 1800 (for example, the first apparatus 110 in FIG. 1) may comprise means for performing the respective operations of the method 1800. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The first apparatus may be implemented as or included in the first apparatus 110 in FIG. 1.

[0217] In some example embodiments, the first apparatus comprises means for determining that a packet from a PDCP entity of the first apparatus is to be duplicated on a plurality of RLC entities of the first apparatus; means for assigning, by the PDCP entity based on the determination, duplicated PDCP packets across a plurality of RLC entities of the first apparatus with a common RLC SN; and means for transmitting the duplicated PDCP packets with the common RLC SN to a second apparatus.

[0218] In some example embodiments, the first apparatus further comprises: means for indicating, to the second apparatus via a capability reporting, that an assignment of the common RLC SN for the duplicated PDCP packets is supported by the first apparatus.

[0219] In some example embodiments, the first apparatus further comprises: means for indicating, to the second apparatus via layer 2, L2, signalling that a PDCP duplication is activated at the first apparatus. In some example embodiments, the L2 signalling comprises medium access control control elements, MAC CE.

[0220] In some example embodiments, a data radio bearer, DRB, is indicated in the MAC CE.

[0221] In some example embodiments, the first apparatus comprises a transmitter and the second apparatus comprises a receiver.

[0222] In some example embodiments, a second apparatus capable of performing any of the method 1900 (for example, the second apparatus 120 in FIG. 1) may comprise means for performing the respective operations of the method 1900. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The second apparatus may be implemented as or included in the second apparatus 120 in FIG. 1.

[0223] In some example embodiments, the second apparatus comprises means for receiving, at a plurality of RLC entities of the second apparatus, duplicated PDCP packets from a first apparatus; means for in accordance with a determination that the duplicated PDCP packets are assigned with a common RLC SN, re-assembling by a PDCP entity of the second apparatus, an RLC data unit based on at least one duplicated PDCP packet of the duplicated PDCP packets.

[0224] In some example embodiments, the second apparatus further comprises: means for in accordance with a determination that an indication received from the first apparatus indicating that a PDCP duplication is activated at the first apparatus, activating the data re-assembly at the PDCP entity.

[0225] In some example embodiments, the second apparatus further comprises: means for in accordance with a determination that the RLC data unit is completely re-assembled based on a duplicated PDCP packet from a first RLC entity in the plurality of RLC entities, discarding duplicated PDCP packets from other RLC entities in the plurality of RLCentities.

[0226] In some example embodiments, the second apparatus further comprises: means for in accordance with a determination that the RLC data unit is not completely reassembled based on a duplicated PDCP packet from a first RLC entity in the plurality of RLC entities, determining whether a lacking portion of the RLC data unit is obtainable from one or more other RLC entities in the plurality of RLC entities; and means for in accordance with a determination that the lacking portion of the RLC data unit is obtainable, re-assembling the RLC data unit based on the duplicated PDCP packet from the first RLC entity and duplicated PDCP packets from the one or more other RLC entities.

[0227] In some example embodiments, the second apparatus further comprises: means for in accordance with a determination that an RLC status report is triggered, retrieving a status of a receiver window from the PDCP entity; and means for generating the RLC status report based on the retrieved status within the receiver window.

[0228] In some example embodiments, the second apparatus further comprises: means for in accordance with a determination that the RLC data unit is completely re-assembled based on at least one duplicated PDCP packet in the duplicated PDCP packets assigned with the common RLC SN, indicating in the RLC status report, an acknowledgement for the duplicated PDCP packets.

[0229] In some example embodiments, the second apparatus further comprises: means for in accordance with a determination that no duplicated PDCP packet in the duplicated PDCP packets is available for re-assembling the RLC data unit individually, indicating in the RLC status report, a non-acknowledgement for the duplicated PDCP packets.

[0230] In some example embodiments, the RLC status report is limited to the highest SN received from the plurality of RLC entities.

[0231] In some example embodiments, the first apparatus comprises a transmitter and the second apparatus comprises a receiver.

[0232] In some example embodiments, a first apparatus capable of performing any of the method 2000 (for example, the first apparatus 110 in FIG. 1) may comprise means for performing the respective operations of the method 2000. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The first apparatus may be implemented as or included in the firstapparatus 110 in FIG. 1.

[0233] In some example embodiments, the first apparatus comprises means for determining a mapping between RLC SNs and PDCP SNs; means for in accordance with a determination that a packet from a PDCP entity of the first apparatus is to be duplicated on a plurality of RLC entities of the first apparatus, determining by a plurality of RLC entities, a same RLC SN of duplicated PDCP packets across the plurality of RLC entities based on the mapping and a PDCP SN of the duplicated PDCP packets; and means for transmitting the duplicated PDCP packets with the same RLC SN to a second apparatus.

[0234] In some example embodiments, the first apparatus further comprises: means for indicating, to the second apparatus via layer 2, L2, signalling that a PDCP duplication is activated at the first apparatus. In some example embodiments, the L2 signalling comprises medium access control control elements, MAC CE.

[0235] In some example embodiments, a data radio bearer, DRB, is indicated in the MAC CE.

[0236] In some example embodiments, the first apparatus comprises a transmitter and the second apparatus comprises a receiver.

[0237] In some example embodiments, a second apparatus capable of performing any of the method 2100 (for example, the second apparatus 120 in FIG. 1) may comprise means for performing the respective operations of the method 2100. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The second apparatus may be implemented as or included in the second apparatus 120 in FIG. 1.

[0238] In some example embodiments, the second apparatus comprises means for receiving duplicated PDCP packets from a first apparatus; and means for in accordance with a determination that the duplicated PDCP packets are with a same RLC SN, reassembling an RLC data unit based on at least one duplicated PDCP packet of the duplicated PDCP packets.

[0239] In some example embodiments, the second apparatus further comprises: means for in accordance with a determination that an indication received from the first apparatus indicating that a PDCP duplication is activated at the first apparatus, activating the data re-assembly at the PDCP entity.

[0240] In some example embodiments, the second apparatus further comprises: means for in accordance with a determination that the RLC data unit is completely re-assembled based on a duplicated PDCP packet from a first RLC entity in the plurality of RLC entities, discarding duplicated PDCP packets from other RLC entities in the plurality of RLC entities.

[0241] In some example embodiments, the second apparatus further comprises: means for in accordance with a determination that the RLC data unit is not completely reassembled based on a duplicated PDCP packet from a first RLC entity in the plurality of RLC entities, determining whether a lacking portion of the RLC data unit is obtainable from one or more other RLC entities in the plurality of RLC entities; and means for in accordance with a determination that the lacking portion of the RLC data unit is obtainable, re-assembling the RLC data unit based on the duplicated PDCP packet from the first RLC entity and duplicated PDCP packets from the one or more other RLC entities.

[0242] In some example embodiments, the second apparatus further comprises: means for in accordance with a determination that the RLC data unit is completely re-assembled based on at least one duplicated PDCP packet in the duplicated PDCP packets assigned with the common RLC SN, indicating in the RLC status report, an acknowledgement for the duplicated PDCP packets.

[0243] In some example embodiments, the second apparatus further comprises: means for in accordance with a determination that no duplicated PDCP packet in the duplicated PDCP packets is available for re-assembling the RLC data unit individually, indicating in the RLC status report, a non-acknowledgement for the duplicated PDCP packets.

[0244] In some example embodiments, the first apparatus comprises a transmitter and the second apparatus comprises a receiver.

[0245] FIG. 22 is a simplified block diagram of a device 2200 that is suitable for implementing example embodiments of the present disclosure. The device 2200 may be provided to implement a communication device, for example, the first apparatus 110 or the second apparatus 120 as shown in FIG. 1. As shown, the device 2200 includes one or more processors 2210, one or more memories 2220 coupled to the processor 2210, and one or more communication modules 2240 coupled to the processor 2210.

[0246] The communication module 2240 is for bidirectional communications. Thecommunication module 2240 has one or more communication interfaces to facilitate communication with one or more other modules or devices. The communication interfaces may represent any interface that is necessary for communication with other network elements. In some example embodiments, the communication module 2240 may include at least one antenna.

[0247] The processor 2210 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 2200 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.

[0248] The memory 2220 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) 2224, an electrically programmable read only memory (EPROM), a flash memory, a hard disk, a compact disc (CD), a digital video disk (DVD), an optical disk, a laser disk, and other magnetic storage and / or optical storage. Examples of the volatile memories include, but are not limited to, a random-access memory (RAM) 2222 and other volatile memories that will not last in the power-down duration.

[0249] A computer program 2230 includes computer executable instructions that are executed by the associated processor 2210. The instructions of the program 2230 may include instructions for performing operations / acts of some example embodiments of the present disclosure. The program 2230 may be stored in the memory, e.g., the ROM 2224. The processor 2210 may perform any suitable actions and processing by loading the program 2230 into the RAM 2222.

[0250] The example embodiments of the present disclosure may be implemented by means of the program 2230 so that the device 2200 may perform any process of the disclosure as discussed with reference to FIG. 4 to FIG. 21. The example embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

[0251] In some example embodiments, the program 2230 may be tangibly contained in a computer readable medium which may be included in the device 2200 (such as in thememory 2220) or other storage devices that are accessible by the device 2200. The device 2200 may load the program 2230 from the computer readable medium to the RAM 2222 for execution. In some example embodiments, the computer readable medium may include any types of non-transitory storage medium, such as ROM, EPROM, a flash memory, a hard disk, CD, DVD, and the like. 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).

[0252] FIG. 23 shows an example of the computer readable medium 2300 which may be in form of CD, DVD or other optical storage disk. The computer readable medium 2300 has the program 2230 stored thereon.

[0253] 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, and other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. Although 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.

[0254] Some example embodiments of the present disclosure also provide at least one computer program product tangibly stored on a computer readable medium, such as a non-transitory computer readable medium. The computer program product includes computerexecutable instructions, such as those included in program modules, being executed in a device on a target physical or virtual processor, to carry out any of the methods as described above. 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.

[0255] Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. The program code may be provided to a processor or controller of a general-purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program code, 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.

[0256] In the context of the present disclosure, the computer program code 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.

[0257] 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.

[0258] Further, although 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, although 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. Unless explicitly stated, certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, unless explicitly stated, various features that are described in the context ofa single embodiment may also be implemented in a plurality of embodiments separately or in any suitable sub-combination.

[0259] 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

WE CLAIM:

1. A first apparatus comprising:at least one processor; andat least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus to:determine that a packet from a packet data convergence protocol, PDCP, entity of the first apparatus is to be duplicated on a plurality of radio link control, RLC, entities of the first apparatus;assign, based on the determination by at least one linked RLC entity, duplicated PDCP packets across a plurality of radio link control, RLC, entities of the first apparatus with a common RLC sequence number, SN; andtransmit the duplicated PDCP packets with the common RLC SN to a second apparatus.

2. The first apparatus of claim 1, wherein the at least one linked RLC entity is operated between the PDCP entity and the plurality of RLC entities or as a function provided by either the PDCP entity or the plurality of RLC entities.

3. The first apparatus of claim 1 or 2, wherein the at least one linked RLC entity comprises a common linked RLC entity, and wherein the plurality of RLC entities of a plurality of cell groups is associated with the common linked RLC entity.

4. The first apparatus of claim 1 or 2, wherein the at least one linked RLC entity comprises a first linked RLC entity and a second linked RLC entity, and wherein a first portion of RLC entities of a first cell group is associated with the first linked RLC entity and a second portion of RLC entities of a second cell group is associated with the second linked RLC entity.

5. The first apparatus of any of claims 1-4, wherein the first apparatus is caused to: indicate, to the second apparatus via a capability reporting, that an assignment of the common RLC SN for the duplicated PDCP packets is supported by the first apparatus.

6. The first apparatus of any of claims 1-5, wherein the first apparatus is caused to: indicate, to the second apparatus via layer 2, L2, signalling that a PDCP duplication is activated at the first apparatus, wherein the L2 signalling comprises medium access control element, MAC CE.

7. The first apparatus of claim 6, wherein a data radio bearer, DRB, is indicated in the MAC CE.

8. The first apparatus of any of claims 1-7, wherein the first apparatus comprises a transmitter and the second apparatus comprises a receiver.

9. A second apparatus comprising:at least one processor; andat least one memory storing instructions that, when executed by the at least one processor, cause the second apparatus to:receive, at a plurality of RLC entities of the second apparatus, duplicated PDCP packets from a first apparatus;cause the duplicated PDCP packets to be delivered from the plurality of RLC entities to at least one linked RLC entity of the second apparatus;in accordance with a determination that the duplicated PDCP packets are assigned with a common RLC SN, re-assemble, by the at least one linked RLC entity, an RLC data unit based on at least one duplicated PDCP packet of the duplicated PDCP packets; andcause the reassembled RLC data unit to be sent to a PDCP entity of the second apparatus.

10. The second apparatus of claim 9, wherein the second apparatus is caused to: in accordance with a determination that an indication received from the first apparatus indicating that a PDCP duplication is activated at the first apparatus, activate the at least one linked RLC entity of the second apparatus.

11. The second apparatus of claim 9 or 10, wherein the second apparatus is caused to: in accordance with a determination that the RLC data unit is completely re-assembled based on a duplicated PDCP packet from a first RLC entity in the plurality of RLC entities, discard duplicated PDCP packets from other RLC entities in the plurality of RLC entities.

12. The second apparatus of claim 11, wherein the second apparatus is caused to: in accordance with a determination that the RLC data unit is not completely reassembled based on a duplicated PDCP packet from a first RLC entity in the plurality of RLC entities, determine whether a lacking portion of the RLC data unit is obtainable from one or more other RLC entities in the plurality of RLC entities; andin accordance with a determination that the lacking portion of the RLC data unit is obtainable, re-assemble the RLC data unit based on the duplicated PDCP packet from the first RLC entity and duplicated PDCP packets from the one or more other RLC entities.

13. The second apparatus of any of claims 9-12, wherein the second apparatus is caused to:in accordance with a determination that an RLC status report is triggered, retrieve a status of a receiver window from the at least one linked RLC entity; andgenerate the RLC status report based on the retrieved status within the receiver window.

14. The second apparatus of claim 13, wherein the second apparatus is caused to: in accordance with a determination that the RLC data unit is completely re-assembled based on at least one duplicated PDCP packet in the duplicated PDCP packets assigned with the common RLC SN, indicate, in the RLC status report, an acknowledgement for the duplicated PDCP packets.

15. The second apparatus of claim 13, wherein the second apparatus is caused to: in accordance with a determination that no duplicated PDCP packet in the duplicated PDCP packets is available for re-assembling the RLC data unit individually, indicate, in the RLC status report, a non-acknowledgement for the duplicated PDCP packets.

16. The second apparatus of any of claims 13-15, wherein the RLC status report is limited to the highest SN received from the plurality of RLC entities.

17. The second apparatus of any of claims 9-16, wherein the at least one linked RLC entity is between the PDCP entity and the plurality of RLC entities or as a function provided by either the PDCP entity or the plurality of RLC entities.

18. The second apparatus of any of claims 9-17, wherein the at least one linked RLC entity comprises a common linked RLC entity, and wherein the plurality of RLC entities of a plurality of cell groups is associated with the common linked RLC entity.

19. The second apparatus of any of claims 9-17, wherein the at least one linked RLC entity comprises a first linked RLC entity and a second linked RLC entity, and wherein a first portion of RLC entities of a first cell group is associated with the first linked RLC entity and a second portion of RLC entities of a second cell group is associated with the second linked RLC entity.

20. The second apparatus of any of claims 13-19, wherein the first apparatus comprises a transmitter and the second apparatus comprises a receiver.

21. A method comprising:determining, at a first apparatus, that a packet from a packet data convergence protocol, PDCP, entity of the first apparatus is to be duplicated on a plurality of radio link control, RLC, entities of the first apparatus;assigning, based on the determination by at least one linked RLC entity, duplicated PDCP packets across a plurality of radio link control, RLC, entities of the first apparatus with a common RLC sequence number, SN; andtransmitting the duplicated PDCP packets with the common RLC SN to a second apparatus.

22. A method comprising:receiving, at a plurality of RLC entities of the second apparatus, duplicated PDCP packets from a first apparatus;causing the duplicated PDCP packets to be delivered from the plurality of RLC entities to at least one linked RLC entity of the second apparatus;in accordance with a determination that the duplicated PDCP packets are assigned with a common RLC SN, re-assembling by the at least one linked RLC entity, an RLC data unit based on at least one duplicated PDCP packet of the duplicated PDCP packets; andcausing the reassembled RLC data unit to be sent to a PDCP entity of the second apparatus.

23. A first apparatus comprising:means for determining that a packet from a packet data convergence protocol, PDCP, entity of the first apparatus is to be duplicated on a plurality of radio link control, RLC, entities of the first apparatus;means for assigning, based on the determination by at least one linked RLC entity, duplicated PDCP packets across a plurality of radio link control, RLC, entities of the first apparatus with a common RLC sequence number, SN; andmeans for transmitting the duplicated PDCP packets with the common RLC SN to a second apparatus.

24. A second apparatus comprising:means for receiving, at a plurality of RLC entities of the second apparatus, duplicated PDCP packets from a first apparatus;means for causing the duplicated PDCP packets to be delivered from the plurality of RLC entities to at least one linked RLC entity of the second apparatus;means for in accordance with a determination that the duplicated PDCP packets are assigned with a common RLC SN, re-assembling by the at least one linked RLC entity, an RLC data unit based on at least one duplicated PDCP packet of the duplicated PDCP packets; andmeans for causing the reassembled RLC data unit to be sent to a PDCP entity of the second apparatus.

25. A computer readable medium comprising instructions stored thereon for causing an apparatus at least to perform the method of claim 21 or the method of claim 22.

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