Method and apparatus for delay status reporting in a wireless communication system

Abstract

The disclosure relates to a 5th generation (5G) or 6th generation (6G) communication system for supporting a higher data transmission rate. Embodiments disclosed herein describe a method and User Equipment (UE) (100) for delay status reporting (DSR) in Extended Reality (XR) within a communication system. The method involves the UE identifying Packet Data Convergence Protocol (PDCP) Service Data Units (SDUs) for DSR at a transmitting PDCP entity. The UE receives a PSI-based SDU discard deactivation indication and detects whether a discard timer for low importance is active for the PDCP SDUs. The method further includes the UE determining the PDCP SDUs as delay-critical for DSR when the discard timer for low importance is active. This solution prioritizes delay-sensitive data in XR applications, ensuring timely transmission and reducing the risk of data loss in the communication system.

Description

[Rectified under Rule 91, 20.02.2025]METHOD AND APPARATUS FOR DELAY STATUS REPORTING IN A WIRELESS COMMUNICATION SYSTEM

[0001] The present application relates to communication systems and more specifically relates to delay status reporting (DSR) for Extended Reality (XR) in a communication system.

[0002] 5G mobile communication technologies define broad frequency bands such that high transmission rates and new services are possible, and can be implemented not only in "Sub 6GHz" bands such as 3.5GHz, but also in "Above 6GHz" bands referred to as mmWave including 28GHz and 39GHz. In addition, it has been considered to implement 6G mobile communication technologies (referred to as Beyond 5G systems) in terahertz (THz) bands (for example, 95GHz to 3THz bands) in order to accomplish transmission rates fifty times faster than 5G mobile communication technologies and ultra-low latencies one-tenth of 5G mobile communication technologies.

[0003] At the beginning of the development of 5G mobile communication technologies, in order to support services and to satisfy performance requirements in connection with enhanced Mobile BroadBand (eMBB), Ultra Reliable Low Latency Communications (URLLC), and massive Machine-Type Communications (mMTC), there has been ongoing standardization regarding beamforming and massive MIMO for mitigating radio-wave path loss and increasing radio-wave transmission distances in mmWave, supporting numerologies (for example, operating multiple subcarrier spacings) for efficiently utilizing mmWave resources and dynamic operation of slot formats, initial access technologies for supporting multi-beam transmission and broadbands, definition and operation of BWP (BandWidth Part), new channel coding methods such as a LDPC (Low Density Parity Check) code for large amount of data transmission and a polar code for highly reliable transmission of control information, L2 pre-processing, and network slicing for providing a dedicated network specialized to a specific service.

[0004] Currently, there are ongoing discussions regarding improvement and performance enhancement of initial 5G mobile communication technologies in view of services to be supported by 5G mobile communication technologies, and there has been physical layer standardization regarding technologies such as V2X (Vehicle-to-everything) for aiding driving determination by autonomous vehicles based on information regarding positions and states of vehicles transmitted by the vehicles and for enhancing user convenience, NR-U (New Radio Unlicensed) aimed at system operations conforming to various regulation-related requirements in unlicensed bands, NR UE Power Saving, Non-Terrestrial Network (NTN) which is UE-satellite direct communication for providing coverage in an area in which communication with terrestrial networks is unavailable, and positioning.

[0005] Moreover, there has been ongoing standardization in air interface architecture / protocol regarding technologies such as Industrial Internet of Things (IIoT) for supporting new services through interworking and convergence with other industries, IAB (Integrated Access and Backhaul) for providing a node for network service area expansion by supporting a wireless backhaul link and an access link in an integrated manner, mobility enhancement including conditional handover and DAPS (Dual Active Protocol Stack) handover, and two-step random access for simplifying random access procedures (2-step RACH for NR). There also has been ongoing standardization in system architecture / service regarding a 5G baseline architecture (for example, service based architecture or service based interface) for combining Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC) for receiving services based on UE positions.

[0006] As 5G mobile communication systems are commercialized, connected devices that have been exponentially increasing will be connected to communication networks, and it is accordingly expected that enhanced functions and performances of 5G mobile communication systems and integrated operations of connected devices will be necessary. To this end, new research is scheduled in connection with eXtended Reality (XR) for efficiently supporting AR (Augmented Reality), VR (Virtual Reality), MR (Mixed Reality) and the like, 5G performance improvement and complexity reduction by utilizing Artificial Intelligence (AI) and Machine Learning (ML), AI service support, metaverse service support, and drone communication.

[0007] Furthermore, such development of 5G mobile communication systems will serve as a basis for developing not only new waveforms for providing coverage in terahertz bands of 6G mobile communication technologies, multi-antenna transmission technologies such as Full Dimensional MIMO (FD-MIMO), array antennas and large-scale antennas, metamaterial-based lenses and antennas for improving coverage of terahertz band signals, high-dimensional space multiplexing technology using OAM (Orbital Angular Momentum), and RIS (Reconfigurable Intelligent Surface), but also full-duplex technology for increasing frequency efficiency of 6G mobile communication technologies and improving system networks, AI-based communication technology for implementing system optimization by utilizing satellites and AI (Artificial Intelligence) from the design stage and internalizing end-to-end AI support functions, and next-generation distributed computing technology for implementing services at levels of complexity exceeding the limit of UE operation capability by utilizing ultra-high-performance communication and computing resources.

[0008] The present disclosure provides method and apparatus for delay status reporting in a wireless communication system.

[0009] According to an aspect of an exemplary embodiment, there is provided a communication method in a wireless communication.

[0010] Aspects of the present disclosure provide an efficient communication methods in a wireless communication system.

[0011] This invention is illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:

[0012] FIG 1 is a block diagram of a UE (100) for an enhanced SDU discard mechanism for the XR in a communication system according to embodiments as disclosed herein.

[0013] FIG 2 is a flowchart (200) that illustrates a method for the Delay Status Reporting (DSR) for the XR in the communication system according to embodiments as disclosed herein.

[0014] FIG 3 is a flowchart (300) that illustrates a method for determining PDCP SDUs as the delay critical PDCP SDUs for the Delay Status Reporting (DSR) for the XR in the communication system according to embodiments as disclosed herein.

[0015] FIG 4 is a flowchart (400) that illustrates a mechanism for reporting capability information of the UE (100) to support the delay critical and non-delay critical data according to embodiments as disclosed herein.

[0016] Figure 5 illustrates various hardware components of a UE, according to the embodiments as disclosed herein; and

[0017] Figure 6 illustrates various hardware components of a BS (base station) according to the embodiments as disclosed herein.

[0018] In an aspect, the objects are achieved by providing a method for DSR for (XR) in a communication system. The method includes identifying, by a UE, PDCP SDUs for the DSR at a transmitting PDCP entity of the UE. Further, the method includes detecting, by the UE, whether a discard timer for low importance is running for the PDCP SDUs. Furthermore, the method includes determining, by the UE, the PDCP SDUs as delay-critical PDCP SDUs for the DSR, when the discard timer for low importance is running for the PDCP SDUs.

[0019] In an embodiment, the PDCP SDUs are determined as the delay-critical PDCP SDUs for the DSR based on the reception of PDU Set Importance (PSI)-based SDU discard deactivation indication by the UE.

[0020] In an embodiment, the PDCP SDUs are determined as the delay-critical PDCP SDUs for the DSR based on a comparison of a remaining time for the PDCP SDUs against a predefined or configured remaining time threshold for the discard timer for low importance.

[0021] In an embodiment, a remaining time for the PDCP SDUs is less than a predefined or configured remaining time threshold until expiration of the discard timer for low importance.

[0022] In an embodiment, the PDCP SDUs are determined as the delay-critical PDCP SDUs for the DSR based on PDCP SDUs including non-delay critical data being ahead of PDCP SDUs including delay critical data in the PDCP buffer.

[0023] In an embodiment, the method includes determining, by the UE, whether a PDU-Set discard configuration is active and classifying, by the UE, all the PDCP SDUs, comprising both stored and newly received PDCP SDUs, within a PDU Set. The PDU Set includes at least one PDCP SDUs as the delay-critical PDCP SDUs. Further, the method includes transmitting, by the UE, a delay-critical indication for a corresponding PDCP PDU to lower layers from the PDCP entity when PDCP data PDU has already submitted to the lower layers of the UE.

[0024] In an embodiment, the method includes determining, by the UE, capability information of the UE for including non-delay critical data ahead of delay critical data in a buffer size calculation for the DSR; and transmitting, by the UE, the capability information to a network apparatus in the communication system.

[0025] In an aspect, the objects are achieved by providing a UE for performing the DSR for the XR in a communication system. The UE includes a memory, a processor, and a DSR controller connected to the memory and the processor. The DSR controller identifies PDCP Service Data Units (SDUs) for the DSR at a transmitting Packet Data Convergence Protocol (PDCP) entity of the UE, detects whether a discard timer for low importance is running for the PDCP SDUs and determines the PDCP SDUs as delay-critical PDCP SDUs for the DSR, when the discard timer for low importance is running for the PDCP SDUs.

[0026] In an embodiment, the UE includes, DSR controller determines whether a PDU-Set discard configuration is active, classifies all the PDCP SDUs, comprising both stored and newly received PDCP SDUs, within a PDU Set, wherein the PDU Set includes at least one PDCP SDU, as the delay-critical PDCP SDU and transmits a delay-critical indication for a corresponding PDCP PDU to lower layers from the PDCP entity (105) when PDCP data PDU has already submitted to the lower layers (such the RLC layer (106), the MAC layer (107), and the PHY layer (108)) from the PDCP entity (105).

[0027] In an embodiment, the UE includes, PDCP SDUs are determined as the delay-critical PDCP SDUs for the DSR based on the reception of PDU Set Importance (PSI)- based SDU discard deactivation indication by the UE.

[0028] In an embodiment, the UE includes, PDCP SDUs are determined as the delay-critical PDCP SDUs based on a comparison of a remaining time for the discard timer for low importance for the PDCP SDUs against a configured remaining time threshold.

[0029] In an embodiment, the UE includes, a remaining time until expiration of the discard timer for low importance for the PDCP SDUs is less than a configured remaining time threshold.

[0030] In an embodiment, the UE includes, PDCP SDUs are determined as the delay-critical PDCP SDUs for the DSR based on PDCP SDUs including non-delay critical data being ahead of PDCP SDUs including delay critical data in the PDCP buffer.

[0031] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein, and the embodiments herein include all such modifications.

[0032] The present application is based on and claims priority from Indian Provisional Application Number 202441003717, filed on 18th January 2024, the disclosure of which is hereby incorporated by reference herein.

[0033] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. Also, the various embodiments described herein are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments. The term "or" as used herein, refers to a non-exclusive or, unless otherwise indicated. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein can be practiced and to further enable those skilled in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.

[0034] As is existing in the field, embodiments may be described and illustrated in terms of blocks which carry out a described function or functions. These blocks, which may be referred to herein as units or modules or the like, are physically implemented by analog or digital circuits such as logic gates, integrated circuits, microprocessors, microcontrollers, memory circuits, passive electronic components, active electronic components, optical components, hardwired circuits, or the like, and may optionally be driven by firmware. The circuits may, for example, be embodied in one or more semiconductor chips, or on substrate supports such as printed circuit boards and the like. The circuits constituting a block may be implemented by dedicated hardware, or by a processor (e.g., one or more programmed microprocessors and associated circuitry), or by a combination of dedicated hardware to perform some functions of the block and a processor to perform other functions of the block. Each block of the embodiments may be physically separated into two or more interacting and discrete blocks without departing from the scope of the invention. Likewise, the blocks of the embodiments may be physically combined into more complex blocks without departing from the scope of the invention

[0035] The accompanying drawings are used to help easily understand various technical features and it should be understood that the embodiments presented herein are not limited by the accompanying drawings. As such, the present disclosure should be construed to extend to any alterations, equivalents and substitutes in addition to those which are particularly set out in the accompanying drawings. Although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are generally only used to distinguish one element from another.

[0036] In the rapidly evolving landscape of wireless communication, the integration of XR applications poses unique challenges, particularly in terms of ensuring timely data delivery and efficient network resource utilization. Extended reality applications, which encompass augmented reality (AR), virtual reality (VR), and mixed reality (MR), demand high data throughput and low latency to provide seamless user experiences. The existing system, as defined in the 3GPP TS 38.323 v1800 standard, attempts to address these demands through a PDU Set Importance (PSI)-based discard mechanism. However, this system has notable limitations that can hinder the performance of XR applications, especially when it comes to handling packet discard and delay status reporting.

[0037] One significant drawback of the current PSI-based discard mechanism is its inability to adapt to changing network conditions, particularly after congestion has subsided. When congestion triggers the PSI-based SDU discard activation, discard timers for low importance packets are initiated. These timers, however, continue to run even after the network congestion is resolved, leading to unnecessary early discards of packets that might otherwise have been successfully transmitted. This premature discard not only results in data loss but also prevents these packets from being considered in delay status reporting (DSR). Consequently, the network fails to accurately assess the delay status of these packets, impairing its ability to allocate uplink resources effectively and potentially degrading the overall quality of service for XR applications.

[0038] To overcome these limitations, the proposed invention introduces an enhanced method and UE for delay status reporting and packet discard handling tailored for XR in wireless networks. This method involves a more dynamic approach to managing discard timers and delay status reporting. Upon receiving a PSI-based SDU discard deactivation indication from the network, the UE is empowered to reassess the running discard timers for low importance PDCP SDUs. The UE can either incorporate these PDCP SDUs into the delay status report, thereby providing the network with a more comprehensive view of the packet delay landscape, or it can stop the existing discard timer and initiate a new one with a recalibrated timer value that reflects the current network conditions. This flexibility ensures that packets are not prematurely discarded and that the network can make informed scheduling decisions, enhancing the performance and reliability of XR applications in wireless networks.

[0039] Extended Reality (XR), an umbrella term that encompasses Virtual Reality (VR), Augmented Reality (AR), and Mixed Reality (MR), represents a transformative advancement in human-computer interaction. This technology, which is a significant component of 5G and 5G-Advanced communication systems, is poised to revolutionize the way individuals engage with digital environments, offering immersive experiences that blend real and virtual worlds. The XR is also considered for the development of digital twins and the meta-universe, promising to enhance various sectors including entertainment, education, healthcare, and remote work.

[0040] Despite its potential, the integration of XR services into existing and future wireless networks presents numerous challenges. The 3GPP New Radio (NR) framework, which is tasked with supporting XR, accommodate the demanding requirements of these applications, including high data rates, ultra-low latency, and power-efficient connectivity. As XR applications become more prevalent, the pressure on network infrastructure to efficiently manage these requirements intensifies.

[0041] A Protocol Data Convergence Protocol (PDCP) layer is responsible for various functionalities, such as Service Data Unit (SDU) discard, ciphering, integrity protection, header compression, reordering, deciphering, integrity verification, duplicate discarding, and header decompression. These functions are used for maintaining the security, efficiency, and reliability of data transmission in wireless networks.

[0042] However, the existing mechanisms employed by the PDCP for handling SDUs, particularly the SDU discard process, are not well-suited for the unique demands of XR applications. XR services often involve tightly coupled frame or PDU Set transmissions rather than the typical one-to-one mapping of IP packets to PDCP SDUs. This discrepancy can lead to inefficiencies, especially in scenarios of network congestion where the allocation of transmission resources become scarce.

[0043] In such congested environments, there is a need for differential treatment of PDCP SDUs based on their importance, referred to as PDU Set Importance (PSI).

[0044] It is desired to address the above-mentioned disadvantages or other short- comings or at least provide a useful alternative.

[0045] The principal object of the invention herein is to provide a method and a User Equipment (UE) for delay status reporting and packet discard handling mechanisms for extended reality in wireless networks.

[0046] Another objective of the invention herein is to consider non-delay-critical PDCP SDUs for the DSR reporting.

[0047] Yet another objective of the invention herein is to handle timers for the non-delay-critical PDCP SDUs in different scenarios.

[0048] Referring now to the drawings, and more particularly to FIGS. 1 to 3, there are shown preferred embodiments.

[0049] FIG 1 is a block diagram of a UE (100) for an enhanced SDU discard mechanism for the XR in a communication system. The UE (100) includes a processor (101), a memory (102), a communicator (103), and the DSR controller (104).

[0050] The UE (100) described herein can be smartphones, tablets, laptops, wearables, Internet of Things (IoT) devices, smart home devices, television, connected car, and USB modems, and the like mobile phone, a personal digital assistance (PDA), etc. These devices are equipped with various sensors and interfaces to support XR applications, such as accelerometers, gyroscopes, cameras, and microphones, enabling immersive user experiences. The XR applications may include augmented reality (AR), virtual reality (VR), and mixed reality (MR), which require high data rates and low latency to function effectively. Further, the UE (100) may support edge computing capabilities, allowing it to offload computationally intensive tasks to nearby servers, reducing the processing burden on the device itself.

[0051] The UE (100) includes a protocol stack of mobile communication systems like a Packet data convergence protocol (PDCP) layer / entity (105), a Radio Link Control (RLC) layer / entity (106), a Medium Access Control (MAC) layer / entity (107), and a Physical (PHY) layer / entity (108). The PDCP layer / entity (105) is responsible for header compression, encryption, and integrity protection of data packets, ensuring secure and efficient data transmission. The RLC layer (106) manages the segmentation and reassembly of data packets, as well as error correction through Automatic Repeat reQuest (ARQ) mechanisms, which are used for maintaining data integrity in XR applications. The MAC layer (107) handles the scheduling and prioritization of data packets, coordinating access to the shared wireless medium to optimize network resource utilization. The PHY layer (108) is responsible for the modulation and demodulation of signals, as well as the transmission and reception of data over the air interface, utilizing advanced techniques such as OFDM (Orthogonal Frequency Division Multiplexing) and beamforming to enhance signal quality and coverage.

[0052] The processor (101) is responsible for executing instructions and managing the overall operation of the UE (100), including the enhanced SDU discard mechanism. The processor (101) communicates with the memory (102), the communicator (103) and the DSR controller (104). The processor (101) is configured to execute instructions stored in the memory (102) and to perform various processes for real-time data processing in XR applications. The processor (101) may include one or a plurality of processors, maybe a general-purpose processor, such as a central processing unit (CPU), an application processor (AP), or the like, a graphics-only processing unit such as a graphics processing unit (GPU), a visual processing unit (VPU), and / or an Artificial intelligence (AI) dedicated processor such as a neural processing unit (NPU).

[0053] The memory (102) stores the operating system, application software, and temporary data used by the processor (101). The memory (102) stores Physical Downlink Control Channel (PDCCH) information, Downlink Control Information (DCI) information, and Physical Downlink Shared Channel (PDSCH) information. The memory (102) stores instructions to be executed by the processor (101). The memory (102) may include non-volatile storage elements. Examples of such non-volatile storage elements may include magnetic hard discs, optical discs, floppy discs, flash memories, or forms of electrically programmable memories (EPROM) or electrically erasable and programmable (EEPROM) memories. In addition, the memory (102) may, in some examples, be considered a non-transitory storage medium. The term "non-transitory" may indicate that the storage medium is not embodied in a carrier wave or a propagated signal. However, the term "non-transitory" should not be interpreted that the memory (102) is non-movable. In some examples, the memory (102) can be configured to store larger amounts of information than the memory. In an example, a non-transitory storage medium may store data that can, over time, change (e.g., in Random Access Memory (RAM) or cache).

[0054] The communicator (103) facilitates wireless communication with the network, supporting various communication protocols such as LTE, 5G, 6G and Wi-Fi, and it may include multiple antennas for MIMO (Multiple Input Multiple Output) operations to enhance data throughput and reliability. Further, the communicator (103) is configured for communicating internally between internal hardware components and with external devices (client device) via one or more networks. The communicator (103) includes an electronic circuit specific to a standard that enables wired or wireless communication.

[0055] The DSR controller (104) is a specialized hardware designed to manage the discard and retransmission of SDUs (Service Data Units) based on the PSI, ensuring that XR data streams are delivered with minimal latency and packet loss. The DSR controller (104) handles the discard of SDUs based on their importance and urgency, ensuring that data is transmitted in a timely manner. When the DSR controller (104) initiates a process to identify which PDCP SDUs are considered delay-critical. This identification is used for maintaining a quality of service in scenarios where network resources are constrained or when the UE (100) is operating in a challenging environment.

[0056] Upon receiving the PSI based SDU discard deactivation indication, the DSR controller (104) determines whether a discard timer for low importance SDUs is currently active. This discard timer is a mechanism that helps manage a lifecycle of PDCP SDUs by discarding those deemed not relevant after a time period (e.g. packet delay budget). However, in cases where the timer is running, the DSR controller (104) assesses whether the PDCP SDUs should be classified or reclassified as delay-critical. This classification is based on a comparison of the remaining time of the discard timer for the SDUs against a predefined or configured threshold. When the remaining time until the expiration of the discard timer is less than this threshold, the SDUs are tagged as delay-critical, indicating that they require immediate attention to prevent data loss.

[0057] In an embodiment, the DSR controller (104) evaluates the urgency of the SDUs. The predefined or configured remaining time threshold serves as a benchmark for determining the data. By ensuring that SDUs with a remaining time below this threshold are prioritized, the proposed invention can effectively manage network resources and optimize data transmission. This solution enhances the reliability of data delivery and supports the seamless operation of applications that rely on timely data exchange. Further, the XR-DSR controller's (104) ability to dynamically adjust the priority of the PDCP SDUs based on real-time conditions is a key feature that enhances the overall performance and efficiency of the UE (100) in various network scenarios.

[0058] The DSR controller (104) determines whether a PDU-Set discard configuration is active and classifies all the PDCP SDUs, within a PDU Set as the delay-critical PDCP SDUs. Wherein, the PDCP SDUs includes both stored and newly received PDCP SDUs and the PDU Set includes at least one PDCP SDU. The DSR controller (104) transmits a delay-critical indication for a corresponding PDCP PDU to lower layers (such the RLC layer (106), the MAC layer (107), and the PHY layer (108)) from the PDCP entity (105) when PDCP data PDU has already submitted to the lower layers of the UE (100). The DSR controller (104) manages the data transmission within a communication system by evaluating the status of the PDU-Set discard configuration. This configuration is used for optimizing network performance, particularly in scenarios. By determining whether this configuration is active, the DSR controller (104) can make informed decisions about how to handle the data packets, known as PDCP SDUs, that are part of a PDU Set. These PDCP SDUs encompass both the data packets that have been stored previously and those that are newly received, ensuring that all relevant data is considered in the decision-making process. Within the PDU Set, the DSR controller (104) identifies the PDCP SDUs as delay-critical. This classification maintains the quality of service, especially for applications that require low latency, such as voice over IP or real-time video streaming. By prioritizing these delay-critical PDCP SDUs, the DSR controller (104) ensures that they are processed and transmitted with minimal delay, thereby enhancing the user experience and maintaining the integrity of time-sensitive communications. Once the PDCP data PDUs have been submitted to the lower layers of the UE (100), the DSR controller (104) transmits a delay-critical indication to these layers. This indication serves as a signal to the lower layers that the corresponding PDCP PDU requires expedited handling. By doing so, the DSR controller (104) facilitates a seamless flow of data through the network, minimizing potential bottlenecks and ensuring that critical data reaches its destination promptly.

[0059] The DSR controller (104) determines capability of the UE (100) for including non-delay critical data ahead of delay critical data in a buffer size calculation for the DSR. The capability pertains to the UE's ability to prioritize non-delay critical data over delay-critical data, a feature that can significantly optimize the data handling process. By prioritizing non-delay critical data, the system can ensure that resources are allocated more effectively, reducing potential bottlenecks and improving overall network performance. Further, the DSR controller (104) transmits the capability information to a network apparatus in the communication system. This transmission of capability information allows the network apparatus to adjust its operations based on the specific capabilities of the UE (100). Such adjustments can include modifying scheduling algorithms, reallocating bandwidth, or altering the prioritization of data packets. This dynamic interaction between the UE (100) and the network apparatus ensures that the communication system remains adaptable and responsive to varying conditions and requirements.

[0060] In an embodiment, the DSR controller (104) is designed for a specific XR service, a specific XR radio bearer, a specific XR QoS flow, or collectively for the XR services, XR radio bearers, or XR QoS flows. The DSR controller (104) includes at least one of the following: a congestion threshold of the PSI value (e.g., below which the PSI-based discard handling is applicable), a list of PSI values (for which the PSI-based discard handling is applicable and / or for which the PSI-based discard handling is not applicable), a list of applicable QoS flows or DRBs to which the PSI-based discard handling is applicable, and a list of timers for discard timer(s) or discard timer for low importance(s) pertaining to the different values of PSI values for the relevant DRB(s).

[0061] FIG 2 is a flowchart (200) that illustrates a method for the DSR for the XR in the communication system.

[0062] At step 201, the method includes identifying by the UE (100) PDCP SDUs for the DSR at a transmitting PDCP entity (105) of the UE (100). This involves scanning the buffer of the PDCP entity (105) to detect SDUs that are marked for potential retransmission or have been flagged as requiring handling due to their role in the DSR process. The identification process may utilize metadata tags or information associated with the SDU(s), which indicate their priority level or importance level and relevance to the DSR.

[0063] At step 202, the method includes receiving by the UE (100) a PSI-based SDUs discard deactivation indication. PSI-based SDU discard activation indication is typically sent by the network to inform the UE (100) that the SDU discard should be differentially pursued based on the PSI so as the important or critical SDUs can be prioritized for transmission (for example, in congestion scenario). PSI-based SDU discard deactivation indication is typically sent by the network to inform the UE (100) that the SDU discard can be performed irrespective of the PSI (for example, in non-congestion scenario). The PSI-based SDU discard activation or PSI-based SDU discard deactivation indication is derived from the network's assessment of the current traffic load and the importance of maintaining data flows. The UE (100) processes this indication by updating its internal discard policies.

[0064] At step 203, the method includes determining by the UE (100) whether a discard timer for low importance is running for the PDCP SDUs. This involves checking the status of timers associated with the SDUs, which are set based on the SDU's priority and the network's discard policy. The UE (100) may utilize a hierarchical timer management system, where different classes of SDUs have distinct timer settings. If the timer is active, the UE (100) evaluates whether the SDU should be retained or discarded, taking into account factors such as network congestion and the SDU's role in ongoing communication sessions.

[0065] At step 204, the method includes determining by the UE (100) the PDCP SDUs as delay-critical PDCP SDUs for the DSR. This determination is based on criteria such as the SDU's role in real-time applications, its priority level, its importance level, its position in the data buffer, its packet delay budget and the current state of the network. The UE (100) may employ machine learning algorithms to dynamically assess the criticality of each SDU, adjusting its classification in real-time. Delay-critical SDUs are then marked for expedited processing and transmission, ensuring that they are prioritized over less critical data in the communication pipeline.

[0066] At step 205, if PDU-Set discard configuration is active, the method includes determining whether the determined PDCP SDUs as delay-critical PDCP SDUs for the DSR have a discard timer for low importance running, which is important for DSR at a transmitting PDCP entity (105) of the UE (100). This step involves cross-referencing the discard configuration settings with the current status of each SDU's timer. The UE (100) may implement a decision matrix that considers both the discard configuration and the SDU's criticality to decide whether to override the timer. This ensures that delay-critical SDUs are not prematurely discarded, maintaining the integrity of the DSR process.

[0067] At step 206, the method includes the UE (100) classifying all the PDCP SDUs, comprising both stored and newly received PDCP SDUs within a PDU Set. This classification process involves sorting SDUs into categories based on their priority, delay sensitivity, and relevance to ongoing communication sessions. The UE (100) may utilize a multi-tiered classification system that allows for fine-grained control over SDU handling. This system can dynamically adjust classifications in response to changes in network conditions or application requirements, ensuring optimal data flow management.

[0068] At step 207, the method includes the UE (100) transmitting a delay-critical indication for a corresponding PDCP PDU to lower layers from the PDCP entity (105) when a PDCP data PDU has already been submitted to the lower layers of the UE (100). This ensures that delay-critical data is transmitted with minimal latency, supporting the requirements of real-time applications and maintaining the quality of service.

[0069] In an embodiment, the method includes the UE (100) may also adjust the scheduling and transmission parameters for these PDUs, prioritizing them in the transmission queue

[0070] FIG. 3 is a flowchart (300) that illustrates a method for determining PDCP SDUs as the delay critical PDCP SDUs for the DSR for the XR in the communication system.

[0071] At step 301, the method including by the UE (100), PDCP SDUs are determined as the delay-critical PDCP SDUs for the DSR based on the reception of PSI-based SDU discard deactivation indication by the UE (100).

[0072] At step 302, the method including by the UE (100), based on a comparison of a remaining time for the discard timer for low importance for the PDCP SDUs against a configured remaining time threshold.

[0073] At step 303, the method including by the UE (100), remaining time until expiration of the discard timer for low importance for the PDCP SDUs is less than a configured remaining time threshold.

[0074] At step 304, the method including by the UE (100), PDCP SDUs are determined as the delay-critical PDCP SDUs for the DSR based on PDCP SDUs including non-delay critical data being ahead of PDCP SDUs including delay critical data in the PDCP buffer.

[0075] FIG. 4 is a flowchart (400) illustrates a mechanism for reporting capability information of the UE (100) to support delay critical and non-delay critical data.

[0076] At step 401, the method including by the UE (100) determines capability of the UE (100) for including non-delay critical data ahead of delay critical data in a buffer size calculation for the DSR. This determination process involves the UE assessing its current hardware and software configurations, such as processor speed, memory capacity, and available bandwidth. The UE may utilize built-in sensors and diagnostic tools to gather this information, ensuring that the data reported is accurate and reflective of its current state. Further, the UE may consider historical data usage patterns and predictive analytics to enhance the accuracy of its capability assessment, allowing for more efficient buffer size calculations that prioritize non-delay critical data.

[0077] At step 402, the method including by the UE (100) transmits the capability information to a network apparatus in the communication system. This transmission is typically carried out using a secure and reliable communication protocol to ensure that the data is not compromised during transit. The UE may employ encryption techniques to protect the integrity and confidentiality of the capability information. Once received, the network apparatus can analyze the data to adjust its resource allocation strategies, potentially using machine learning algorithms to predict future network conditions and optimize data handling. This step is crucial for maintaining an adaptive and responsive communication system that can dynamically adjust to the varying demands of different data types.

[0078] In an embodiment, upon PSI-based SDU discard is deactivated, the transmitting PDCP entity (105) stops the discard timer for low importance (if running) for the PDCP SDU and starts the discard timer with the remaining value of the discard timer low importance for the PDCP SDU. Further, the PDCP SDU is considered for the DSR reporting when the remaining time of the discard timer becomes lower than the configured remaining time threshold of the logical channel Group (LCG) to which the PDCP SDU pertains.

[0079] In an embodiment, upon PSI-based SDU discard is deactivated, the transmitting PDCP entity (105) stops the discard timer for low importance (if running) for the PDCP SDU and starts the discard timer with a value of (configured discard timer value minus elapsed time duration of the discard timer low importance) for the PDCP SDU. Further, the PDCP SDU is considered for the DSR reporting when the remaining time of the discard timer becomes lower than the configured remaining time threshold of the LCG to which the PDCP SDU pertains.

[0080] In an embodiment, upon PSI-based SDU discard is deactivated, the transmitting PDCP entity (105) stops the discard timer for low importance (if running) for the PDCP SDU and starts the discard timer with a value of (configured discard timer value minus remaining time duration of the discard timer low importance) for the PDCP SDU. Further, the PDCP SDU is considered for the DSR reporting when the remaining time of the discard timer becomes lower than the configured remaining time threshold of the LCG to which the PDCP SDU pertains.

[0081] In an embodiment, upon PSI-based SDU discard is deactivated, the transmitting PDCP entity (105) stops the discard timer for low importance (if running) for the PDCP SDU and starts the discard timer with a value of configured discard timer value for the PDCP SDU. Further, the PDCP SDU is considered for the DSR reporting when the remaining time of the discard timer becomes lower than the configured remaining time threshold of the LCG to which the PDCP SDU pertains.

[0082] In an embodiment, the transmitting PDCP entity (105) considers the PDCP SDU(s) with a running discard timer for low importance for delay-critical PDCP data volume in the non-congestion scenario. More particularly, a delay-critical PDCP SDU is re-defined as the PDCP SDU for which the remaining time till discard timer or discard timer for low importance (if PSI-based SDU discard is deactivated) expiry is less than a remaining time threshold. If the pdu-SetDiscard is configured, all PDCP SDUs (including both already stored PDCP SDUs and newly received PDCP SDUs) belonging to the PDU Set to which at least one delay-critical PDCP SDU belongs are considered as delay-critical PDCP SDUs. If the corresponding PDCP Data PDU has already been submitted to lower layers, the delay-critical indication for the PDCP Data PDU is provided to lower layers.

[0083] In an embodiment, the transmitting PDCP entity (105) considers the PDCP SDU(s) with a running discard timer for low importance for delay-critical PDCP data volume in both the congestion and non-congestion scenarios. Further, a delay-critical PDCP SDU is re-defined as the PDCP SDU for which the remaining time till discard timer or discard timer for low importance expiry is less than a remaining time threshold. If the pdu-SetDiscard is configured, all the PDCP SDUs (including both already stored the PDCP SDUs and newly received PDCP SDUs) belonging to the PDU Set to which at least one delay-critical PDCP SDU belongs are considered as delay-critical PDCP SDUs. If the corresponding PDCP Data PDU has already been submitted to the lower layers, the delay-critical indication for the PDCP Data PDU is provided to the lower layers.

[0084] In an embodiment, when the PSI-based SDU discard is deactivated, the transmitting PDCP entity (105) appends the discard timer for low importance (if running) for the PDCP SDU with an additional time duration. This additional duration appended may be one of the following:

[0085] 1. The configured discard timer value minus the configured discard timer low importance value.

[0086] 2. The configured discard timer value minus the elapsed time duration of the discard timer low importance of the PDCP SDU.

[0087] 3. The configured discard timer value minus the remaining time duration of the discard timer low importance of the PDCP SDU.

[0088] 4. The configured discard timer value.

[0089] These configurations ensure that the discard timer is adjusted appropriately based on the importance and timing of the PDCP SDU.

[0090] In an embodiment, the PDCP SDU is considered for the DSR reporting when the remaining time of the discard timer for low importance becomes lower than the configured remaining time threshold of the LCG to which the PDCP SDU pertains. Upon deactivation of the PSI-based SDU discard, the transmitting PDCP entity (105) continues the discard timer for low importance, if it is running. Upon the timer's expiry, the PDCP SDU is discarded.

[0091] In an embodiment, when the PSI-based SDU discard is deactivated, the transmitting PDCP entity (105) considers the PDCP SDU for which the discard timer for low importance is running for the DSR, such as when considering the buffer size reporting in the DSR MAC control element. In an embodiment, the PDCP SDU may be considered for the DSR reporting when the remaining time of the discard timer for low importance becomes lower than the configured remaining time threshold of the LCG to which the PDCP SDU pertains.

[0092] In an embodiment, it is left up to the UE implementation to handle the case that upon PSI-based SDU discard is deactivated, the PDCP SDU for which discard timer for low importance is running (e.g. whether considering for the buffer size reporting in the DSR MAC control element, whether discarding or not discarding the PDCP SDU upon timer expiry and so on)

[0093] In an embodiment, when the PSI-based SDU discard is activated, such as in a congestion scenario, the transmitting PDCP entity (105) stops the discard timer (if it is running) for the PDCP SDU associated with low importance packets. Subsequently, the discard timer for low importance is initiated and started with the remaining value of the discard timer for an associated PDCP SDU. Further, the PDCP SDU may not be considered for the DSR reporting.

[0094] In an embodiment, when the PSI-based SDU discard is activated, such as in a congestion scenario, the transmitting PDCP entity (105) stops the discard timer (if it is running) for the PDCP SDU related to low importance packets. Subsequently, the discard timer for low importance is initiated and started with a value calculated as the configured discard timer for low importance minus the elapsed time duration of the discard timer, provided this results in a positive number, for an associated PDCP SDU. Further, the PDCP SDU may not be considered for the DSR reporting.

[0095] In an embodiment, when the PSI-based SDU discard is activated, such as in a congestion scenario, the transmitting PDCP entity (105) stops the discard timer (if it is running) for the PDCP SDU associated with low importance packets. Subsequently, a discard timer for low importance is initiated and started with a value calculated as the configured discard timer for low importance minus the remaining time duration of the original discard timer, provided this calculation results in a positive number, for the PDCP SDU. Further, the PDCP SDU may not be considered for the DSR reporting.

[0096] In an embodiment, when the PSI-based SDU discard is activated, such as in a congestion scenario, the transmitting PDCP entity (105) stops the discard timer (if it is running) for the PDCP SDU associated with low importance packets. Subsequently, a discard timer for low importance is initiated and started with a value corresponding to the configured discard timer for low importance for the PDCP SDU. Further, the PDCP SDU may be excluded from consideration for the DSR reporting.

[0097] In an embodiment, when the PSI-based SDU discard is activated, such as in a congestion scenario, the transmitting PDCP entity (105) subtracts a time duration from the discard timer (if it is running) for the PDCP SDU related to low importance packets. The subtracted duration may be one of the following: the configured discard timer value minus the configured discard timer low importance value, or simply the configured discard timer low importance value. If the result after subtraction is negative or zero, the PDCP SDU is discarded.

[0098] In an embodiment, upon PSI-based SDU discard is activated (e.g., in a congestion scenario), for a PDU Set if at least one PDCP SDU is having a discard timer running and at least one PDCP SDU is having a discard timer for low importance running, the transmitting PDCP entity discards all the PDCP SDUs of the PDU Set when a discard timer for low importance is expired.

[0099] In an embodiment, upon PSI-based SDU discard is activated (e.g., in a congestion scenario), for a PDU Set if at least one PDCP SDU is having a discard timer running and at least one PDCP SDU is having a discard timer for low importance running, the transmitting PDCP entity discards all the PDCP SDUs of the PDU Set when at least one of the timer is expired.

[0100] In an embodiment, upon PSI-based SDU discard is deactivated (e.g., in a non-congestion scenario), for a PDU Set if at least one PDCP SDU is having a discard timer running and at least one PDCP SDU is having a discard timer for low importance running, the transmitting PDCP entity discards all the PDCP SDUs of the PDU Set when a discard timer is expired.

[0101] In an embodiment, when the PSI-based SDU discard is deactivated (e.g. in a non-congestion scenario), for a PDU Set if at least one PDCP SDU is having a discard timer running and at least one PDCP SDU is having a discard timer for low importance running, the transmitting PDCP entity discards all the PDCP SDUs of the PDU Set when a discard timer is expired.

[0102] In an embodiment, upon PSI-based SDU discard is deactivated (non-congestion scenario), for a PDU Set if at least one PDCP SDU is having a discard timer running and at least one PDCP SDU is having a discard timer for low importance running, the transmitting PDCP entity discards all the PDCP SDUs of the PDU Set when a discard timer for low importance is expired.

[0103] In an embodiment, upon PSI-based SDU discard is activated (e.g., in a congestion scenario), for a PDU Set if at least one PDCP SDU is having a discard timer running and at least one PDCP SDU is having a discard timer for low importance running, the transmitting PDCP entity (105) discards all the PDCP SDUs of the PDU Set when a discard timer for low importance is expired or a discard timer is expired or at least one of the timer is expired.

[0104] In one embodiment, the transmitting PDCP entity (105) evaluates the PDCP SDU(s) with a running discard timer as having low importance for delay-critical PDCP data volume in a non-congestion scenario. More specifically, a delay-critical PDCP SDU is redefined as the PDCP SDU for which the remaining time until the discard timer, or the discard timer for low importance (if the PSI-based SDU discard is deactivated), expires is less than a remaining time threshold.

[0105] In an embodiment, the transmitting PDCP entity (105) considers the PDCP SDU(s) with running discard timer for low importance for delay critical PDCP data volume in both the congestion and non-congestion scenario. More particularly, a delay-critical PDCP SDU is re-defined as the PDCP SDU for which the remaining time till discard timer or discard timer for low importance expiry is less than a remaining time threshold.

[0106] In an embodiment, the UE (100) also support including non-delay critical data ahead of delay critical data in the buffer size calculation for the DSR, which is a capability indicated to the NW.

[0107] In an embodiment, there may be one or more instances of discard timer for low importance. These different instances of timers for low importance may have same or differently configured or pre-specified timer values.

[0108] In an embodiment, discard timer for low importance may corresponds to one or more modes of communication for XR sevices (e.g. in a multi-model communication).

[0109] In an embodiment, discard timer for low importance may corresponds to one or more QoS flows for XR sevices (e.g. QoS flows carrying less critical data or QoS flows carrying data with higher latency bounds).

[0110] In an embodiment, discard timer for low importance may also correspond to discard timer values configured and / or utilized in the non-congestion scenarios.

[0111] Hence, the proposed invention introduces an innovative solution to the DSR mechanisms tailored for the XR applications. Unlike existing systems, in which the non-delay critical SDUs are not be reported in the DSR but use up the grants scheduled by the network, this invention focuses on optimizing the reporting of the DSR by considering the non-delay-critical PDCP SDUs. By doing so, it ensures that the network can prioritize and manage data packets based on their urgency and relevance to the XR experience, thereby enhancing the overall performance and user experience.

[0112] Figure 5 illustrates various hardware components of a UE, according to the embodiments as disclosed herein.

[0113] As shown in FIGURE 5, the base station according to an embodiment may include a transceiver 510, a memory 520, and a processor 530. The transceiver 510, the memory 520, and the processor 530 of the base station may operate according to a communication method of the base station described above. However, the components of the base station are not limited thereto. For example, the base station may include more or fewer components than those described above. In addition, the processor 530, the transceiver 510, and the memory 520 may be implemented as a single chip. Also, the processor 530 may include at least one processor. In addition, the UE of Figure 5 correspond to the UE of the Figure 1.

[0114] The transceiver 510 collectively refers to a base station receiver and a base station transmitter, and may transmit / receive a signal to / from a terminal(UE) or a network entity. The signal transmitted or received to or from the terminal or a network entity may include control information and data. The transceiver 510 may include a RF transmitter for up-converting and amplifying a frequency of a transmitted signal, and a RF receiver for amplifying low-noise and down-converting a frequency of a received signal. However, this is only an example of the transceiver 510 and components of the transceiver 510 are not limited to the RF transmitter and the RF receiver.

[0115] Also, the transceiver 510 may receive and output, to the processor 530, a signal through a wireless channel, and transmit a signal output from the processor 530 through the wireless channel.

[0116] The memory 520 may store a program and data required for operations of the base station. Also, the memory 520 may store control information or data included in a signal obtained by the base station. The memory 520 may be a storage medium, such as read-only memory (ROM), random access memory (RAM), a hard disk, a CD-ROM, and a DVD, or a combination of storage media.

[0117] The processor 530 may control a series of processes such that the base station operates as described above. For example, the transceiver 510 may receive a data signal including a control signal transmitted by the terminal, and the processor 530 may determine a result of receiving the control signal and the data signal transmitted by the terminal.

[0118] Figure 6 illustrates various hardware components of a base station according to the embodiments as disclosed herein.

[0119] As shown in figure 6, the UE according to an embodiment may include a transceiver 610, a memory 620, and a processor 630. The transceiver 610, the memory 620, and the processor 630 of the UE may operate according to a communication method of the UE described above. However, the components of the UE are not limited thereto. For example, the UE may include more or fewer components than those described above. In addition, the processor 630, the transceiver 610, and the memory 620 may be implemented as a single chip. Also, the processor 630 may include at least one processor.

[0120] The transceiver 610 collectively refers to a UE receiver and a UE transmitter, and may transmit / receive a signal to / from a base station or a network entity. The signal transmitted or received to or from the base station or a network entity may include control information and data. The transceiver 610 may include a RF transmitter for up-converting and amplifying a frequency of a transmitted signal, and a RF receiver for amplifying low-noise and down-converting a frequency of a received signal. However, this is only an example of the transceiver 610 and components of the transceiver 610 are not limited to the RF transmitter and the RF receiver.

[0121] Also, the transceiver 610 may receive and output, to the processor 630, a signal through a wireless channel, and transmit a signal output from the processor 630 through the wireless channel.

[0122] The memory 620 may store a program and data required for operations of the UE. Also, the memory 620 may store control information or data included in a signal obtained by the UE. The memory 620 may be a storage medium, such as read-only memory (ROM), random access memory (RAM), a hard disk, a CD-ROM, and a DVD, or a combination of storage media.

[0123] The processor 630 may control a series of processes such that the UE operates as described above. For example, the transceiver 610 may receive a data signal including a control signal transmitted by the base station or the network entity, and the processor 630 may determine a result of receiving the control signal and the data signal transmitted by the base station or the network entity.

[0124] One of the key aspects of the proposed invention is its ability to handle timers for non-delay-critical PDCP SDUs across various scenarios as described above. In existing systems, timers are not optimized for the specific requirements of the XR applications, potentially leading to inefficiencies and degraded performance. By tailoring the management of these timers, the invention ensures that non-delay-critical data is processed in a manner that does not interfere with the timely delivery of critical data. The invention allows for a more balanced and efficient use of network resources, ultimately leading to improved XR application performance. The technical advantages of this invention are significant. By implementing an efficient approach to delay status reporting, the invention not only enhances the performance of the UE (100) and network infrastructure but also ensures a more seamless and immersive XR experience. The ability to prioritize data based on its delay sensitivity means that the XR applications can operate with reduced latency and increased reliability.

[0125] The various actions, acts, blocks, steps, or the like in the flow charts may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some of the actions, acts, blocks, steps, or the like may be omitted, added, modified, skipped, or the like without departing from the scope of the invention.

[0126] The embodiments disclosed herein can be implemented through at least one software program running on at least one hardware device and performing network management functions to control the network elements. The elements include blocks which can be at least one of a hardware device, or a combination of hardware device and software module.

[0127] The embodiment disclosed herein describes systems and methods for ensuring that the 5G system is able to provide MPS to specific services (such as, but not limited to, SMS over 5GS and EPS). Therefore, it is understood that the scope of the protection is extended to such a program and in addition to a computer readable means having a message therein, such computer readable storage means contain program code means for implementation of one or more steps of the method, when the program runs on a server or mobile device or any suitable programmable device. The method is implemented in at least one embodiment through or together with a software program written in e.g., Very high speed integrated circuit Hardware Description Language (VHDL) another programming language, or implemented by one or more VHDL or several software modules being executed on at least one hardware device. The hardware device can be any kind of portable device that can be programmed. The device may also include means which could be e.g., hardware means like e.g., an ASIC, or a combination of hardware and software means, e.g. an ASIC and an FPGA, or at least one microprocessor and at least one memory with software modules located therein. The method embodiments described herein could be implemented partly in hardware and partly in software. Alternatively, the invention may be implemented on different hardware devices, e.g., using a plurality of CPUs.

[0128] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and / or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

Claims

1.A method for delay status reporting (DSR) for Extended Reality (XR) in a communication system, comprising:identifying, by a User Equipment (UE), PDCP Service Data Units (SDUs) for the DSR at a transmitting Packet Data Convergence Protocol (PDCP) entity of the UE;detecting, by the UE, whether a discard timer for low importance is running for the PDCP SDUs; anddetermining, by the UE, the PDCP SDUs as delay-critical PDCP SDUs for the DSR, when the discard timer for low importance is running for the PDCP SDUs.2.The method of claim 1, wherein the PDCP SDUs are determined as the delay-critical PDCP SDUs for the DSR based on the reception of PDU Set Importance (PSI)-based SDU discard deactivation indication by the UE.3.The method of claim 1, wherein the PDCP SDUs are determined as the delay-critical PDCP SDUs for the DSR based on a comparison of a remaining time for the discard timer for low importance for the PDCP SDUs against a configured remaining time threshold.4.The method of claim 3, wherein a remaining time until expiration of the discard timer for low importance for the PDCP SDUs is less than a configured remaining time threshold.5.The method of claim 1, wherein the PDCP SDUs are determined as the delay-critical PDCP SDUs for the DSR based on PDCP SDUs including non-delay critical data being ahead of PDCP SDUs including delay critical data in the PDCP buffer.6.The method of claim 1, comprising:determining, by the UE, whether a PDU-Set discard configuration is active;classifying, by the UE, all the PDCP SDUs, comprising both stored and newly received PDCP SDUs, within a PDU Set, wherein the PDU Set includes at least one PDCP SDU, as the delay-critical PDCP SDUs; andtransmitting, by the UE, a delay-critical indication for a corresponding PDCP PDU to lower layers from the PDCP entity when PDCP data PDU has already submitted to the lower layers of the UE.7.The method as claimed in claim 1, comprising:determining, by the UE, capability of the UE for including non-delay critical data ahead of delay critical data in a buffer size calculation for the DSR; andtransmitting, by the UE, the capability information to a network apparatus in the communication system.8.A User Equipment (UE) for delay status reporting (DSR) for Extended Reality (XR) in a communication system, comprising:a memory;a processor; anda DSR controller, connected to the memory and the processor, wherein the DSR controller:identifies PDCP Service Data Units (SDUs) for the DSR at a transmitting Packet Data Convergence Protocol (PDCP) entity of the UE;detects whether a discard timer for low importance is running for the PDCP SDUs; anddetermine the PDCP SDUs as delay-critical PDCP SDUs for the DSR, when the discard timer for low importance is running for the PDCP SDUs.9.The UE of claim 8, wherein the PDCP SDUs are determined as the delay-critical PDCP SDUs for the DSR based on the reception of PDU Set Importance (PSI)-based SDU discard deactivation indication by the UE.10.The UE of claim 8, wherein the PDCP SDUs are determined as the delay-critical PDCP SDUs based on a comparison of a remaining time for the discard timer for low importance for the PDCP SDUs against a configured remaining time threshold.11.The UE of claim 10, wherein a remaining time until expiration of the discard timer for low importance for the PDCP SDUs is less than a configured remaining time threshold.12.The UE of claim 8, wherein the PDCP SDUs are determined as the delay-critical PDCP SDUs for the DSR based on PDCP SDUs including non-delay critical data being ahead of PDCP SDUs including delay critical data in the PDCP buffer.13.The UE of claim 8, wherein the DSR controller:determines whether a PDU-Set discard configuration is active;classifies all the PDCP SDUs, comprising both stored and newly received PDCP SDUs, within a PDU Set, wherein the PDU Set includes at least one PDCP SDU, as the delay-critical PDCP SDUs; andtransmits a delay-critical indication for a corresponding PDCP PDU to lower layers from the PDCP entity when PDCP data PDU has already submitted to the lower layers of the UE.14.The UE of claim 8, wherein the DSR controller:determines capability of the UE for including non-delay critical data ahead of delay critical data in a buffer size calculation for the DSR; andtransmits the capability information to a network apparatus in the communication system.

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