Method and apparatus for managing HARQ feedback in wireless communication system

Abstract

The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. The principal object of embodiments herein is to disclose methods and systems for managing Hybrid Automatic Repeat Request (HARQ) feedback in a Non-Terrestrial Network (NTN). Another object of embodiments herein is to disclose methods and systems for managing Non-Terrestrial Network (NTN) operation for Multicast and Broadcast Services (MBS) multicast in an RRC_INACTIVE state.

Description

METHOD AND APPARATUS FOR MANAGING HARQ FEEDBACK IN WIRELESS COMMUNICATION SYSTEM

[0001] Embodiments disclosed herein relate to wireless communication networks and more particularly, to methods and systems for performing Hybrid Automatic Repeat Request (HARQ) operations for Non-Terrestrial Network (NTN).

[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 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] Non-Terrestrial Networks (NTNs) provide a non-terrestrial access to the User Equipment (UE) and may comprise of an NTN payload (for example, a satellite) and an NTN Gateway. The NTN payload has a service link to the UE, and the NTN Gateway has a feeder link to the NTN Payload. The NTN can be deployed to provide coverage with at least one of earth-moving cell, quasi-earth-fixed cell and earth-fixed cell. Further, there is a need to accommodate the propagation delay in NTNs, for example, Round-Trip-Time (RTT) for the service link.

[0009] New Radio Multicast and Broadcast Service (NR MBS) services can refer to multicast services where intended common contents are targeted to a group of User Equipment (UEs) which have joined the multicast group in the multicast coverage area and broadcast services where intended contents may be targeted to all the UEs in the broadcast coverage area.

[0010] Two delivery methods are envisioned for Fifth Generation (5G) MBS service, from the viewpoint of a 5G Core Network (CN):

[0011] - an individual MBS traffic delivery method, and

[0012] - a shared MBS traffic delivery method.

[0013] For the individual MBS traffic delivery method, the CN receives a single copy of MBS data packets and delivers separate copies of those MBS data packets to individual UEs via per-UE Protocol Data Unit (PDU) sessions. For the shared MBS traffic delivery method, the 5G CN receives a single copy of MBS data packets and delivers a single copy of those MBS packets to a Radio Access Node (RAN), which then delivers the MBS packets to one or multiple UEs. The RAN delivers the MBS data to the UEs using either Point-to-Point delivery (PTP) or Point-to-Multipoint (PTM) delivery. Further, at the UE, the MBS bearer can comprise a common Packet Data Convergence Protocol　(PDCP)　entity with PTP, PTM or a combination of PTP and PTM legs or Radio Link Control (RLC) entities.

[0014] The MAC entity includes a Hybrid Automatic Repeat Request (HARQ)　entity for each Serving Cell, which maintains a plurality of parallel HARQ processes. Each HARQ process is associated with a HARQ process identifier. The HARQ entity directs the HARQ information and associated Transport Blocks (TBs) received on the Downlink Shared Channel (DL-SCH) to the corresponding HARQ processes. There are a number of parallel DL HARQ processes per HARQ entity. The dedicated broadcast HARQ process is used for broadcast control channels (BCCH). If the physical layer is not configured for downlink spatial multiplexing, the HARQ process supports one TB. If the physical layer is configured for downlink spatial multiplexing, the HARQ process supports one or two TBs.

[0015] For NTN downlink, HARQ feedback can be enabled or disabled per HARQ process. Disabling HARQ feedback allows scheduling a HARQ process before one HARQ RTT has elapsed since last scheduled.

[0016] HARQ processes are also needed to support MBS multicast; for example, for transmission and / or retransmission on PTM, for transmission and / or retransmission on PTP and for initial transmission on PTM followed by retransmission on PTP. HARQ feedback can be configured by the Radio Resource Control (RRC) signalling and can be enabled or disabled by the scheduling of the Downlink Control Information (DCI) and / or by the indication included in the DCI. HARQ feedback can be ACK / NACK type (also termed as first HARQ-ACK reporting mode) or NACK only type (also termed as second HARQ-ACK reporting mode) and is configured by the RRC signalling.

[0017] There is a possible deployment for NTN data through MBS multicast in a serving cell that is part of the NTN. In this scenario, it is possible that the HARQ process or processes is / are configured with the disabled HARQ feedback, while the MBS multicast configuration for a specific MBS multicast service addressed to a G-RNTI or a G-CSRNTI or a configured downlink allocation may be configured to support HARQ feedback generation. This leads to an ambiguity as how to determine the HARQ feedback generation in this case, as there are two conflicting configurations.

[0018] Hence, there is a need in the art for solutions which will overcome the above mentioned drawback(s), among others.

[0019] The principal object of embodiments herein is to disclose methods and systems for managing Hybrid Automatic Repeat Request (HARQ) feedback in a Non-Terrestrial Network (NTN).

[0020] Another object of embodiments herein is to disclose methods and systems for managing Non-Terrestrial Network (NTN) operation for Multicast and Broadcast Services (MBS) multicast in an RRC_INACTIVE state.

[0021] Another object of embodiments herein is to specify the HARQ process behaviour for determining HARQ feedback generation, where service data on NTN is received through MBS multicast in at least one serving cell that is part of the NTN.

[0022] Another object of the embodiments herein is to enable Point-to-Point delivery (PTP) retransmission(s) for the Point-to-Multipoint (PTM) transmission for MBS multicast in at least one serving cell that is part of the NTN.

[0023] Another object of the embodiments herein is to disclose methods and systems for availing of retransmissions, when the　HARQ process is configured with disabled HARQ feedback by NTN configuration, and the DRX timer (HARQ-RTT-TimerDL-NTN)　is not operated.

[0024] In an embodiment, a method performed by a user equipment (UE) is provided. The method includes identifying that a transmission takes place for in a Hybrid Automatic Repeat Request (HARQ) process; in case that the HARQ process is configured with disabled HARQ feedback and is not associated with a transmission indicated with a Group-Radio Network Temporary Identifier (G-RNTI) or a Group-Configured Scheduling-RNTI (G-CS-RNTI) or a configured downlink assignment for Multicast and Broadcast Services (MBS) multicast, identifying whether a parameter harq-FeedbackEnablingforSPSactive is configured with a value true and the transmission is a first transmission on the configured downlink assignment after activation of the configured downlink assignment; in case that the parameter harq-FeedbackEnablingforSPSactive is configured with the value true and the transmission is the first transmission on the configured downlink assignment after activation of the configured downlink assignment, instructing, by a Medium Access Control (MAC) layer of the UE, a physical layer of the UE to generate at least one acknowledgement of data in a transport block (TB); and in case that either the parameter harq-FeedbackEnablingforSPSactive is not configured with the value true or the transmission is not the first transmission on the configured downlink assignment after activation of the configured downlink assignment, determining, by the MAC layer, not to instruct the physical layer to generate the at least one acknowledgement of data in the TB.

[0025] In an embodiment, a UE is provided. The UE includes at least one transceiver; at least one processor communicatively coupled to the at least one transceiver; and at least one memory, communicatively coupled to the at least one processor, storing instructions executable by the at least one processor individually or in any combination to cause the UE to: identify that a transmission takes place for in a Hybrid Automatic Repeat Request (HARQ) process, in case that the HARQ process is configured with disabled HARQ feedback and is not associated with a transmission indicated with a Group-Radio Network Temporary Identifier (G-RNTI) or a Group-Configured Scheduling-RNTI (G-CS-RNTI) or a configured downlink assignment for Multicast and Broadcast Services (MBS) multicast, identify whether a parameter harq-FeedbackEnablingforSPSactive is configured with a value true and the transmission is a first transmission on the configured downlink assignment after activation of the configured downlink assignment, in case that the parameter harq-FeedbackEnablingforSPSactive is configured with the value true and the transmission is the first transmission on the configured downlink assignment after activation of the configured downlink assignment, instruct, by a Medium Access Control (MAC) layer of the UE, a physical layer of the UE to generate at least one acknowledgement of data in a transport block (TB), and in case that either the parameter harq-FeedbackEnablingforSPSactive is not configured with the value true or the transmission is not the first transmission on the configured downlink assignment after activation of the configured downlink assignment, determine, by the MAC layer, not to instruct the physical layer to generate the at least one acknowledgement of data in the TB.

[0026] Accordingly, the embodiments herein provide a method for managing Hybrid Automatic Repeat Request (HARQ) feedback in a Non-Terrestrial Network (NTN). The method comprises instructing, by a Medium Access Control (MAC) layer of a User Equipment (UE) to a physical layer of the UE, to generate at least one acknowledgement of data in a transport block (TB) in a transmission, if the following conditions are satisfied: a HARQ process is configured with disabled HARQ feedback, and the HARQ process is not associated with the transmission indicated with one of a Group-Radio Network Temporary Identifier (G-RNTI); a Group-Configured Scheduling-RNTI (G-CS-RNTI); and a configured downlink assignment for Multicast and Broadcast Services (MBS) multicast; and a parameter harq-FeedbackEnablingforSPSactive in a Radio Resource Control (RRC) configuration is configured with a value 'true', and the transmission is a first transmission on a configured downlink assignment after activation of a configured downlink assignment. The method further comprises instructing, by the MAC layer of the UE to the physical layer of the UE, to not generate at least one acknowledgement of data in the TB in the transmission, if the following conditions are satisfied: the HARQ process is configured with disabled HARQ feedback, and the HARQ process is not associated with the transmission indicated with one of the G-RNTI; the G-CS-RNTI; and the configured downlink assignment for MBS multicast; and the parameter harq-FeedbackEnablingforSPSactive in the RRC configuration is not configured with a value 'true', and the transmission is not the first transmission on the configured downlink assignment after activation of a configured downlink assignment.

[0027] Accordingly, the embodiments herein provide a method for managing Non-Terrestrial Network (NTN) operation for Multicast and Broadcast Services (MBS) multicast in an RRC_INACTIVE state. The method comprises setting, by a User Equipment (UE), HARQ-RTT-TimerDL-NTN for a Hybrid Automatic Repeat Request (HARQ) process equal to a sum of a drx-HARQ-RTT-TimerDL, and a latest available UE-gNB RTT (Round Trip Time) value, if the following conditions are satisfied: drx-HARQ-RTT-TimerDL-PTM is configured for multicast in RRC_INACTIVE for the UE; the UE supports ptm-RetransmissionInactive; and Physical Downlink Control Channel (PDCCH) is indicated on a NTN. The method further comprises starting a drx-HARQ-RTT TimerDL-PTM-NTN for the HARQ process in a first symbol after end of a multicast transmission.

[0028] Accordingly, the embodiments herein provide a User Equipment (UE) in a Non-Terrestrial Network (NTN), wherein the UE comprises a Medium Access Control (MAC) layer; and a physical layer. The MAC layer is configured to instruct the physical layer, to generate at least one acknowledgement of data in a transport block (TB) in a transmission, if the following conditions are satisfied: a HARQ process is configured with disabled HARQ feedback, and the HARQ process is not associated with the transmission indicated with one of a Group-Radio Network Temporary Identifier (G-RNTI); a Group-Configured Scheduling-RNTI (G-CS-RNTI); and a configured downlink assignment for Multicast and Broadcast Services (MBS) multicast; and a parameter harq-FeedbackEnablingforSPSactive in a Radio Resource Control (RRC) configuration is configured with a value 'true', and the transmission is a first transmission on a configured downlink assignment after activation of a configured downlink assignment. The MAC layer is configured to instruct the physical layer, to generate at least one acknowledgement of data in a transport block (TB) in a transmission, if the following conditions are satisfied: the HARQ process is configured with disabled HARQ feedback, and the HARQ process is not associated with the transmission indicated with one of the G-RNTI; the G-CS-RNTI; and the configured downlink assignment for MBS multicast; and the parameter harq-FeedbackEnablingforSPSactive in the RRC configuration is not configured with a value 'true', and the transmission is not the first transmission on the configured downlink assignment after activation of a configured downlink assignment.

[0029] Accordingly, the embodiments herein provide a User Equipment (UE) in a Non-Terrestrial Network (NTN). The UE can be configured to set a HARQ-RTT-TimerDL-NTN for a Hybrid Automatic Repeat Request (HARQ) process equal to a sum of a drx-HARQ-RTT-TimerDL, and a latest available UE-gNB RTT (Round Trip Time) value, if the following conditions are satisfied: drx-HARQ-RTT-TimerDL-PTM is configured for multicast in RRC_INACTIVE for the UE; the UE supports ptm-RetransmissionInactive; and Physical Downlink Control Channel (PDCCH) is indicated on a NTN. The UE is further configured to start a drx-HARQ-RTT TimerDL-PTM-NTN for the HARQ process in a first symbol after end of a multicast transmission.

[0030] 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 at least one embodiment 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 without departing from the spirit thereof, and the embodiments herein include all such modifications.

[0031] Embodiments herein are 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 following illustratory drawings. Embodiments herein are illustrated by way of examples in the accompanying drawings, and in which:

[0032] FIGs. 1A and 1B illustrate a UE in an NTN, according to embodiments as disclosed herein;

[0033] FIGs. 2A and 2B illustrate the determination for the HARQ feedback generation for service data on NTN through MBS multicast in at least one serving cell that is part of the NTN, according to embodiments as disclosed herein;

[0034] FIG. 3 is a flowchart depicting the process of the UE managing the HARQ feedback in the NTN, according to embodiments as disclosed herein;

[0035] FIG. 4 is a flowchart depicting the process of managing NTN operations for MBS multicast in an RRC_INACTIVE state, according to embodiments as disclosed herein; and

[0036] FIG. 5 is a flowchart illustrating the determination for the HARQ feedback generation for service data on NTN through MBS multicast in at least one serving cell that is part of the NTN, wherein PTP retransmission for MBS multicast transmission is performed, according to embodiments as disclosed herein.

[0037] 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. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.

[0038] For the purposes of interpreting this specification, the definitions (as defined herein) will apply and whenever appropriate the terms used in singular will also include the plural and vice versa. It is to be understood that the terminology used herein is for the purposes of describing particular embodiments only and is not intended to be limiting. The terms "comprising", "having" and "including" are to be construed as open-ended terms unless otherwise noted.

[0039] The words / phrases "exemplary", "example", "illustration", "in an instance", "and the like", "and so on", "etc.", "etcetera", "e.g.," , "i.e.," are merely used herein to mean "serving as an example, instance, or illustration." Any embodiment or implementation of the present subject matter described herein using the words / phrases "exemplary", "example", "illustration", "in an instance", "and the like", "and so on", "etc.", "etcetera", "e.g.," , "i.e.," is not necessarily to be construed as preferred or advantageous over other embodiments.

[0040] Embodiments herein 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 managers, units, modules, hardware components or the like, are physically implemented by analog and / or digital circuits such as logic gates, integrated circuits, microprocessors, microcontrollers, memory circuits, passive electronic components, active electronic components, optical components, hardwired circuits and the like, and may optionally be driven by a 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 disclosure.　Likewise, the blocks of the embodiments may be physically combined into more complex blocks without departing from the scope of the disclosure.

[0041] It should be noted that elements in the drawings are illustrated for the purposes of this description and ease of understanding and may not have necessarily been drawn to scale. For example, the flowcharts / sequence diagrams illustrate the method in terms of the steps required for understanding of aspects of the embodiments as disclosed herein. Furthermore, in terms of the construction of the device, one or more components of the device may have been represented in the drawings by conventional symbols, and the drawings may show only those specific details that are pertinent to understanding the present embodiments so as not to obscure the drawings with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. Furthermore, in terms of the system, one or more components / modules which comprise the system may have been represented in the drawings by conventional symbols, and the drawings may show only those specific details that are pertinent to understanding the present embodiments so as not to obscure the drawings with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.

[0042] 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 modifications, equivalents, and substitutes in addition to those which are particularly set out in the accompanying drawings and the corresponding description. Usage of words such as first, second, third etc., to describe components / elements / steps is for the purposes of this description and should not be construed as sequential ordering / placement / occurrence unless specified otherwise.

[0043] The embodiments herein achieve methods and systems for managing Hybrid Automatic Repeat Request (HARQ) feedback in a Non-Terrestrial Network (NTN). Referring now to the drawings, and more particularly to FIGS. 1A through 5, where similar reference characters denote corresponding features consistently throughout the figures, there are shown embodiments.

[0044] Note that the terminology "transmission" or "PDSCH transmission" as referred to herein refers to a "downlink reception" from the UE perspective.

[0045] FIGs. 1A and 1B illustrate a UE in an NTN. The UE 100, as depicted, comprises a processing module 101, at least one memory 102, and at least one transceiver 103. The UE 100 further comprises a physical layer 100A, and a Medium Access Control (MAC) layer 100B.

[0046] The processing module 101 can be at least one of a single processor, a plurality of processors, multiple homogeneous or heterogeneous cores, multiple Central Processing Units (CPUs) of different kinds, microcontrollers, special media, and other accelerators. The processing module 101 may be an Application Processor (AP), 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).

[0047] In an embodiment herein, the at least one transceiver 103 is configured to enable communication between the UE, and at least one external entity through a network or cloud. The transceiver 103 through which the UE 100 and the at least one external entity communicate may include wired and / or wireless communication medium compatible with one or more different communication protocols. The transceiver 103 may be configured for communication through a network. The network may comprise, but are not limited to, Global Positioning System (GPS), Global System for Mobile Communications (GSM), Local Area Network (LAN), Wireless Fidelity (Wi-Fi) compatibility, Bluetooth Low Energy (BLE), Near-field Communication (NFC), and so on. The wireless communication may further comprise one or more of Bluetooth, Zonal Intercommunication Global Standard (ZigBee), short-range wireless communication such as Ultra-wideband (UWB), medium-range wireless communication such as Wi-Fi, or long-range wireless communication such as Third Generation (3G), Fourth Generation (4G), Fifth Generation (5G), Sixth Generation (6G), or Worldwide Interoperability for Microwave Access (WiMAX), according to the usage environment.

[0048] In the embodiment shown herein, the at least one memory 102 may comprise one or more volatile and non-volatile memory components that are capable of storing data and instructions to be executed. Examples of the at least one memory 102 can be, but are not limited to, NAND, embedded Multimedia Card (eMMC), Secure Digital (SD) cards, Universal Serial Bus (USB), Serial Advanced Technology Attachment (SATA), solid-state drive (SSD), and so on. The at least one memory 102 may also include one or more computer-readable storage media. Examples of 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 at least one 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 to mean that the at least one memory 102 is non-movable. In certain examples, a non-transitory storage medium may store data that can, over time, change (for example, in Random Access Memory (RAM) or cache).

[0049] The UE 100 can manage the HARQ feedback in the NTN. The processing module 101 can check if a HARQ process is configured with disabled HARQ feedback, and the HARQ process is not associated with a transmission indicated with one of a Group-Radio Network Temporary Identifier (G-RNTI); a Group-Configured Scheduling-RNTI (G-CS-RNTI) (i.e., a first condition). The HARQ process can be configured with disabled HARQ feedback for a serving cell that is part of the NTN. The processing module 101 can further check if a configured downlink assignment for Multicast and Broadcast Services (MBS) multicast; and a parameterharq-FeedbackEnablingforSPSactivein a Radio Resource Control (RRC) configuration is configured with a value 'true', and the transmission is a first transmission on a configured downlink assignment after activation of a configured downlink assignment (i.e., a second condition). If both the first and second conditions are satisfied, the MAC layer 100A can instruct the physical layer 100B to generate at least one acknowledgement of data in a transport block (TB) in the transmission. If at least one of the first condition, or the second condition are not satisfied, the MAC layer 100A can instruct the physical layer 100 to not generate at least one acknowledgement of data in the TB in the transmission. In an embodiment herein, the generated acknowledgement can be a positive acknowledgement (ACK) when data in the TB has been successfully decoded. In an embodiment herein, the generated acknowledgement can be a negative acknowledgment (NACK), when data in the TB has not been successfully decoded.

[0050] In an embodiment herein, if the HARQ process is associated with the transmission indicated with one of the G-RNTI; the G-CS-RNTI; and the configured downlink assignment for MBS multicast, the MAC layer 100A can instruct the physical layer 100B to generate at least one acknowledgement for the data in the TB, irrespective of any other listed condition of the HARQ process is configured with disabled HARQ feedback, whether transmission is the first or not the first transmission on the configured downlink assignment after activation of the configured downlink assignment, and whether harq-FeedbackEnablingforSPSactive is configured with a value true or not.

[0051] In an embodiment herein, if the HARQ process is configured with disabled HARQ feedback (for example, for a serving cell that is part of NTN) and is not associated with a transmission indicated with a G-RNTI or a G-CS-RNTI or a configured downlink assignment for MBS multicast and if the parameter 'harq-FeedbackEnablingforSPSactive' is configured with a value 'true' and if the transmission is the first transmission on the configured downlink assignment after activation of the configured downlink assignment, the MAC layer 100A instructs the physical layer 100B to generate acknowledgement(s) of the data in this TB.

[0052] In an embodiment herein, if the HARQ process is configured with disabled HARQ feedback (for example, for a serving cell that is part of NTN) and is not associated with a transmission indicated with a G-RNTI or a G-CS-RNTI or a configured downlink assignment for MBS multicast and if either 'harq-FeedbackEnablingforSPSactive' is not configured with a value true or the transmission is not the first transmission on the configured downlink assignment after activation of the configured downlink assignment, the MAC layer 100A instructs the physical layer 100B to not generate acknowledgement(s) of the data in this TB.

[0053] In an embodiment herein, if the HARQ process is configured with enabled HARQ feedback (for example, for a serving cell that is part of NTN) and is not associated with a transmission indicated with a G-RNTI or a G-CS-RNTI or a configured downlink assignment for MBS multicast, the MAC layer 100A instructs the physical layer 100B to generate acknowledgement(s) of the data in this TB.

[0054] In an embodiment herein, if the HARQ process is configured with disabled HARQ feedback (for example, for a serving cell that is part of NTN) and is associated with a transmission indicated with a G-RNTI or a G-CS-RNTI or a configured downlink assignment for MBS multicast, the MAC layer 100A can decide on HARQ feedback generation, based on the MBS multicast configuration for HARQ feedback for a specific service. In an example, a configuration parameter 'harq-FeedbackEnablerMulticast' may be set to "enabled", thereby implying that the HARQ feedback is generated. 'harq-FeedbackEnablerMulticast' may be set to "DCI-enabler", thereby implying as to whether HARQ feedback is generated or not generated is based on the scheduling of the Downlink Control Information (DCI) (for example, scheduled by multicast DCI format 4_1 associated with the G-RNTI or the G-CS-RNTI) and / or by the indication included in the DCI (for example, an indication by the multicast DCI format 4_2 associated with the G-RNTI for multicast or the G-CS-RNTI). Further, if FeedbackEnablerMulticast is not configured or not set, the MAC layer 100A may determine that the HARQ feedback is not to be generated.

[0055] In an embodiment herein, if the HARQ process is configured with enabled HARQ feedback (for example, for a serving cell that is part of NTN) and is associated with a transmission indicated with a G-RNTI or a G-CS-RNTI or a configured downlink assignment for MBS multicast, the MAC layer 100A can make a determination of the HARQ feedback generation, based on the MBS multicast configuration for HARQ feedback for specific service　(for example, by a configuration parameter 'harq-FeedbackEnablerMulticast'). 'harq-FeedbackEnablerMulticast' may be set to "enabled" implying the HARQ feedback is generated. 'harq-FeedbackEnablerMulticast' may be set to "DCI-enabler" implying as to whether HARQ feedback is to be generated or not generated, based on the scheduling of the DCI (for example, scheduled by multicast DCI format 4_1 associated with the G-RNTI or the G-CS-RNTI) and / or by the indication included in the DCI (for example an indication by the multicast DCI format 4_2 associated with the G-RNTI for multicast or the G-CS-RNTI). Further, if FeedbackEnablerMulticast is not configured or not set, the MAC layer 100A may determine that the HARQ feedback is not to be generated.

[0056] In an embodiment herein (as depicted in FIG. 2), an example MAC specification TS 38.321 for the determination of HARQ feedback generation is provided for addressing the case of HARQ feedback being disabled, as follows:

[0057] Example 1:

[0058] 5.3.2.2 HARQ process

[0059] When a transmission takes place for the HARQ process, one or two (in case of downlink spatial multiplexing) TBs and the associated HARQ information are received from the HARQ entity.

[0060] For each received TB and associated HARQ information, the HARQ process shall:

[0061] 1> if the NDI, when provided, has been toggled compared to the value of the previous received transmission corresponding to this TB; or

[0062] 1> if the HARQ process is equal to the broadcast process, and this is the first received transmission for the TB according to the system information schedule indicated by RRC; or

[0063] 1> if the HARQ process is associated with a transmission indicated with a MCCH-RNTI for MBS broadcast, and this is the first received transmission for the TB according to the broadcast MCCH schedule indicated by RRC; or

[0064] 1> if the HARQ process is associated with a transmission indicated with a Multicast MCCH-RNTI for MBS multicast in RRC_INACTIVE, and this is the first received transmission for the TB according to the multicast MCCH schedule indicated by RRC; or

[0065] 1> if the HARQ process is associated with a transmission indicated with a G-RNTI for MBS broadcast, and this is the first received transmission for the TB according to the MTCH schedule indicated by RRC or according to the scheduling indicated by DCI as specified in TS 38.214 [7]; or

[0066] 1> if this is the very first received transmission for this TB (i.e. there is no previous NDI for this TB):

[0067] 2> consider this transmission to be a new transmission.

[0068] 1> else:

[0069] 2> consider this transmission to be a retransmission.

[0070] The MAC entity then shall:

[0071] 1> if this is a new transmission:

[0072] 2> attempt to decode the received data.

[0073] 1> else if this is a retransmission:

[0074] 2> if the data for this TB has not yet been successfully decoded:

[0075] 3> instruct the physical layer to combine the received data with the data currently in the soft buffer for this TB and attempt to decode the combined data.

[0076] 1> if the data which the MAC entity attempted to decode was successfully decoded for this TB; or

[0077] 1> if the data for this TB was successfully decoded before:

[0078] 2> if the HARQ process is equal to the broadcast process:

[0079] 3> deliver the decoded MAC PDU to upper layers.

[0080] 2> else if this is the first successful decoding of the data for this TB:

[0081] 3> deliver the decoded MAC PDU to the disassembly and demultiplexing entity.

[0082] 1> else:

[0083] 2> instruct the physical layer to replace the data in the soft buffer for this TB with the data which the MAC entity attempted to decode.

[0084] 1> if the HARQ process is associated with a transmission indicated with a Temporary C-RNTI and the Contention Resolution is not yet successful (see clause 5.1.5); or

[0085] 1> if the HARQ process is associated with a transmission indicated with a MSGB-RNTI and the Random Access procedure is not yet successfully completed (see clause 5.1.4a); or

[0086] 1> if the HARQ process is equal to the broadcast process; or

[0087] 1> if the HARQ process is associated with a transmission indicated with a MCCH-RNTI or a G-RNTI for MBS broadcast; or

[0088] 1> if the HARQ process is associated with a transmission indicated with a Multicast MCCH-RNTI for MBS multicast; or

[0089] 1> if the HARQ process is associated with a transmission indicated with a G-RNTI or a G-CS-RNTI or a configured downlink assignment for MBS multicast and HARQ feedback is disabled for this G-RNTI or G-CS-RNTI or the corresponding G-CS-RNTI, as specified in clause 18 of TS 38.213 [6]; or

[0090] 1> if the HARQ process is associated with a transmission indicated with a G-RNTI or a G-CS-RNTI or a configured downlink assignment for MBS multicast and NACK only HARQ feedback is used for this G-RNTI or G-CS-RNTI or the corresponding G-CS-RNTI and the data for this TB is successfully decoded and the transmission is not the first transmission of PDSCH where the configured downlink assignment was (re-)initialized; or

[0091] 1> if the timeAlignmentTimer, associated with the TAG containing the Serving Cell on which the HARQ feedback is to be transmitted, is stopped or expired, and the Serving Cell is not configured with two TAGs, and if the cg-SDT-TimeAlignmentTimer, if configured, is not running; or

[0092] 1> if the Serving Cell on which the HARQ feedback is to be transmitted is configured with two TAGs and if the timeAlignmentTimer of the TAG, associated with the TCI state(s) used for transmitting the HARQ feedback, is stopped or expired:

[0093] 2> not instruct the physical layer to generate acknowledgement(s) of the data in this TB.

[0094] 1> else if the HARQ process is configured with disabled HARQ feedback and is not associated with a transmission indicated with a G-RNTI or a G-CS-RNTI or a configured downlink assignment for MBS multicast:

[0095] 2> if harq-FeedbackEnablingforSPSactive is configured with a value true and the transmission is the first transmission on the configured downlink assignment after activation of the configured downlink assignment:

[0096] 3> instruct the physical layer to generate acknowledgement(s) of the data in this TB.

[0097] 2> else:

[0098] 3> not instruct the physical layer to generate acknowledgement(s) of the data in this TB.

[0099] 1> else:

[0100] 2> instruct the physical layer to generate acknowledgement(s) of the data in this TB.

[0101] The MAC entity shall ignore NDI received in all downlink assignments on PDCCH for its Temporary C-RNTI when determining if NDI on PDCCH for its C-RNTI has been toggled compared to the value in the previous transmission.

[0102] NOTE: If the MAC entity receives a retransmission with a TB size different from the last TB size signaled for this TB, the UE behavior is left up to the UE implementation.

[0103] In an embodiment herein, service data reception on the NTN through MBS multicast can be configured and / or allowed only in RRC_CONNECTED state in at least one serving cell that is part of the NTN. Further, if the HARQ feedback is disabled for the service data reception on the NTN through the MBS multicast, the UE 100 in RRC_CONNECTED state may be configured to receive the retransmissions for the service data on the NTN through MBS multicast that are meant for the other UE(s) which are in RRC_CONNECTED state. The UE 100 may be signaled in the paging or group paging message, while the UE 100 is in RRC_IDLE / RRC_INACTIVE state about the activation of the MBS multicast session in the at least one serving cell that is part of the NTN. The processing module 101 may then establish or resume a RRC connection, and transit to the RRC_CONNECTED state to avail the service data reception on the NTN through MBS multicast.

[0104] In an embodiment herein, the UE 100 may go through a handover across an NTN and a Terrestrial Network (TN) (for example, from NTN to TN or from TN to NTN) to achieve service continuity for the MBS multicast service.

[0105] The processing module 101 can manage NTN operations for MBS multicast in an RRC_INACTIVE state. The processing module 101 can check for the following conditions:

[0106] - if drx-HARQ-RTT-TimerDL-PTM has been configured for multicast in RRC_INACTIVE for the UE 100 (i.e., a third condition);

[0107] - if the UE supports ptm-RetransmissionInactive (i.e., a fourth condition); and

[0108] - if Physical Downlink Control Channel (PDCCH) is indicated on an NTN (i.e., a fifth condition).

[0109] If the third, fourth, and fifth conditions are satisfied, the processing module 101 can set HARQ-RTT-TimerDL-NTN for the HARQ process equal to a sum of a drx-HARQ-RTT-TimerDL, and a latest available UE-gNB RTT (Round Trip Time) value. The processing module 101 can further start a drx-HARQ-RTT-TimerDL-PTM-NTN for the HARQ process in a first symbol after end of the multicast transmission.

[0110] In an embodiment herein, service data reception on the NTN through MBS multicast in the RRC_INACTIVE state is configured and / or allowed in at least one serving cell that is part of the NTN. The configuration may be provided through a RRCRelease with suspendConfig and / or multicast MCCH message on a serving cell that is part of the NTN. Further, HARQ feedback is disabled or considered as disabled for the service data reception on the NTN through the MBS multicast in the RRC_INACTIVE state. Furthermore, the UE 100 in RRC_INACTIVE state may be configured by the processing module 101, to receive the retransmissions for the service data on the NTN through MBS multicast that are meant for the other UE(s) which are in RRC_CONNECTED state.

[0111] In an embodiment herein, the UE 100 may be signaled in the paging or group paging message, while the UE 100 is in RRC_INACTIVE state about the activation of the MBS multicast session in the at least one serving cell that is part of the NTN. For an MBS multicast service that is not configured to be received in RRC_INACTIVE state, the UE 100 may then establish or resume a RRC connection and transit to the RRC_CONNECTED state to avail the service data reception on the NTN through MBS multicast. For an MBS multicast service that is configured to be received in RRC_INACTIVE state, the UE 100 may then continue in the RRC_INACTIVE state and avail the service data reception on the NTN through the MBS multicast.

[0112] In an embodiment herein, service data reception on the NTN through MBS multicast in RRC_INACTIVE state is not configured and / or not allowed in a serving cell that is part of the NTN.

[0113] In an embodiment herein, service data reception on the NTN through MBS broadcast in at least one of RRC_CONNECTED, RRC_INACTIVE and RRC_IDLE state can be configured and / or allowed in a serving cell that is part of the NTN. Further, if the HARQ process is configured with enabled HARQ feedback (for example, for a serving cell that is part of NTN) and is associated with a transmission indicated with a G-RNTI or MCCH-RNTI for MBS broadcast, the UE 100 does not generate a HARQ feedback. Further, if the HARQ process is configured with disabled HARQ feedback (for example, for a serving cell that is part of NTN) and is associated with a transmission indicated with a G-RNTI or MCCH-RNTI for MBS broadcast, the UE 100 does not generate a HARQ feedback.

[0114] In an embodiment herein, service data reception on the NTN through MBS broadcast in at least one of RRC_CONNECTED, RRC_INACTIVE and RRC_IDLE state is not configured and / or not allowed in a serving cell that is part of the NTN.

[0115] In an embodiment herein, for service data reception for the NTN through MBS multicast in RRC_INACTIVE state, if for the UE 100, drx-HARQ-RTT-TimerDL-PTM is configured for multicast in RRC_INACTIVE, and the UE 100 supports ptm-RetransmissionInactive, and if the PDCCH is indicated on a non-terrestrial network, then the processing module 101 sets HARQ-RTT-TimerDL-NTN for the corresponding HARQ process, equal to drx-HARQ-RTT-TimerDL plus the latest available UE-gNB RTT value. The processing module 101 can start the drx-HARQ-RTT-TimerDL-PTM-NTN for the corresponding HARQ process in the first symbol after the end of the corresponding multicast transmission. This is illustrated with an example as follows:

[0116] Example 2:

[0117] 1> ifdrx-HARQ-RTT-TimerDL-PTMis configured for multicast in RRC_INACTIVE:

[0118] 2> if the PDCCH is indicated on a non-terrestrial network and the UE supportsptm-RetransmissionInactive:

[0119] 3> setHARQ-RTT-TimerDL-NTNfor the corresponding HARQ process equal todrx-HARQ-RTT-TimerDLplus the latest available UE-gNB RTT value;

[0120] 3> start thedrx-HARQ-RTT-TimerDL-PTM-NTNfor the corresponding HARQ process in the first symbol after the end of the corresponding multicast transmission.

[0121] In an embodiment herein, if the HARQ process is configured with disabled HARQ feedback (for example for a serving cell that is part of NTN) and is associated with a transmission indicated with a G-RNTI or a G-CS-RNTI or a configured downlink assignment for MBS multicast, the processing module 101 does not apply disabled HARQ feedback for the HARQ process for MBS multicast SPS (re-)activation and / or deactivation (or release). That is, in spite of HARQ process being configured with disabled HARQ feedback, the disabled HARQ feedback is not applicable for MBS multicast SPS (re-)activation and / or SPS deactivation. The UE further provides HARQ feedback for the first PDSCH transmission after MBS multicast SPS (re-)activation and / or for the DCI format indicating SPS deactivation. The processing module 101 can set the HARQ-RTT-TimerDL-PTM-NTN for the corresponding HARQ process equal to drx-HARQ-RTT-TimerDL-PTM plus the latest available UE-gNB RTT value. Further, the processing module 101 can start the HARQ-RTT-TimerDL-PTM-NTN for the corresponding HARQ process in the first symbol after the end of the corresponding transmission carrying the DL HARQ feedback.

[0122] In an embodiment herein, if the HARQ process is configured with disabled HARQ feedback (for example for a serving cell that is part of NTN) and is associated with a transmission indicated with a G-RNTI or a G-CS-RNTI or a configured downlink assignment for MBS multicast, the disabled HARQ feedback for the HARQ process is not applicable for MBS multicast SPS (re-)activation and / or SPS deactivation, the processing module 101 provides the HARQ feedback for the first PDSCH transmission after MBS multicast SPS (re-)activation and / or for the DCI format indicating SPS deactivation as the ACK-NACK (i.e., first HARQ-ACK reporting mode). That is, if the UE receives the PDSCH transmission after MBS multicast SPS activation and / or for the DCI format indicating SPS deactivation, the processing module 101 provides an ACK as HARQ feedback. If the UE does not receive the PDSCH transmission after MBS multicast SPS (re-)activation, the processing module 101 can provide a NACK as HARQ feedback. The processing module 101 can set the HARQ-RTT-TimerDL-PTM-NTN for the corresponding HARQ process equal to drx-HARQ-RTT-TimerDL-PTM plus the latest available UE-gNB RTT value. Further, the processing module 101 can start the HARQ-RTT-TimerDL-PTM-NTN for the corresponding HARQ process in the first symbol after the end of the corresponding transmission carrying the DL HARQ feedback.

[0123] In an embodiment herein, if the HARQ process is configured with disabled HARQ feedback (for example, for a serving cell that is part of NTN) and is associated with a transmission indicated with a G-RNTI or a G-CS-RNTI or a configured downlink assignment for MBS multicast, the disabled HARQ feedback for the HARQ process is not applicable for MBS multicast SPS (re-)activation, the processing module 101 can provide the HARQ feedback for the first PDSCH transmission after MBS multicast SPS (re-)activation as the NACK only (i.e., second HARQ-ACK reporting mode). That is, if the UE receives the PDSCH transmission after MBS multicast SPS (re-)activation, the processing module 101 does not provide any HARQ feedback. If the UE does not receive the PDSCH transmission after MBS multicast SPS activation, the processing module 101 can provide a NACK as HARQ feedback. The processing module 101 can set the HARQ-RTT-TimerDL-PTM-NTN for the corresponding HARQ process equal to drx-HARQ-RTT-TimerDL-PTM plus the latest available UE-gNB RTT value. Further, the processing module 101 can start the HARQ-RTT-TimerDL-PTM-NTN for the corresponding HARQ process in the first symbol after the end of the corresponding transmission carrying the DL HARQ feedback.

[0124] In an embodiment herein, if the HARQ process is configured with disabled HARQ feedback (for example for a serving cell that is part of NTN) and is associated with a transmission indicated with a G-RNTI or a G-CS-RNTI or a configured downlink assignment for MBS multicast, the processing module 101 can provide the HARQ feedback for the DCI formats having associated HARQ feedback information without scheduling a PDSCH reception for the UE. The processing module 101 can set the HARQ-RTT-TimerDL-PTM-NTN for the corresponding HARQ process equal to drx-HARQ-RTT-TimerDL-PTM plus the latest available UE-gNB RTT value. Further, the processing module 101 can start the HARQ-RTT-TimerDL-PTM-NTN for the corresponding HARQ process in the first symbol after the end of the corresponding transmission carrying the DL HARQ feedback.

[0125] In an embodiment herein, if the HARQ process is configured with disabled HARQ feedback (for example, for a serving cell that is part of NTN) and is associated with a transmission indicated with a G-RNTI or a G-CS-RNTI or a configured downlink assignment for MBS multicast, and the PDSCH HARQ-ACK codebook for multicast HARQ feedback is set as dynamic, the processing module 101 can provide the HARQ feedback for the first PDSCH reception after (re-)activation of the multicast SPS or for the DCI formats without scheduling a PDSCH reception for the UE 100. The processing module 101 can set the HARQ-RTT-TimerDL-PTM-NTN for the corresponding HARQ process equal to drx-HARQ-RTT-TimerDL-PTM plus the latest available UE-gNB RTT value. Further, the processing module 101 can start the HARQ-RTT-TimerDL-PTM-NTN for the corresponding HARQ process in the first symbol after the end of the corresponding transmission carrying the DL HARQ feedback.

[0126] In an embodiment herein, if the HARQ process is configured with disabled HARQ feedback (for example, for a serving cell that is part of NTN) and is associated with a transmission indicated with a G-RNTI or a G-CS-RNTI or a configured downlink assignment for MBS multicast, and the PDSCH HARQ-ACK codebook for multicast HARQ feedback is set as semi-static, the processing module 101 can provide the HARQ feedback for the first PDSCH reception after (re-)activation of the multicast SPS or for the DCI formats without scheduling a PDSCH reception for the UE 100. The processing module 101 can set the HARQ-RTT-TimerDL-PTM-NTN for the corresponding HARQ process equal to drx-HARQ-RTT-TimerDL-PTM plus the latest available UE-gNB RTT value. Further, the processing module 101 can start the HARQ-RTT-TimerDL-PTM-NTN for the corresponding HARQ process in the first symbol after the end of the corresponding transmission carrying the DL HARQ feedback.

[0127] In an embodiment herein, for the service data reception for NTN through MBS multicast on at least one serving cell that is part of NTN, when a second reporting mode for HARQ-ACK feedback is configured (i.e., NACK only) and NACK HARQ feedback is converted to ACK / NACK HARQ feedback, the processing module 101 can consider that the first reporting mode is applicable for HARQ feedback. The processing module 101 can further set the HARQ-RTT-TimerDL-PTM-NTN for the corresponding HARQ process equal to drx-HARQ-RTT-TimerDL-PTM plus the latest available UE-gNB RTT value. Further, the processing module 101 can start the HARQ-RTT-TimerDL-PTM-NTN for the corresponding HARQ process in the first symbol after the end of the corresponding transmission carrying the DL HARQ feedback.

[0128] In an embodiment herein, for the service data reception for NTN through MBS multicast on at least one serving cell that is part of the NTN when first reporting mode for HARQ-ACK feedback is configured (i.e., ACK-NACK) and NACK HARQ feedback is converted to ACK / NACK HARQ feedback, the processing module 101 can set the HARQ-RTT-TimerDL-PTM-NTN for the corresponding HARQ process equal to drx-HARQ-RTT-TimerDL-PTM plus the latest available UE-gNB RTT value. Further, the processing module 101 can start the HARQ-RTT-TimerDL-PTM-NTN for the corresponding HARQ process in the first symbol after the end of the corresponding transmission carrying the DL HARQ feedback.

[0129] Embodiments herein can make a determination for the HARQ feedback generation for service data on NTN through MBS multicast in at least one serving cell that is part of the NTN, wherein PTP retransmission for MBS multicast transmission is performed. Note that the terminology "transmission" or "Physical Downlink Shared Channel (PDSCH) transmission" as referred to herein refers to a "downlink reception" from the UE perspective.

[0130] In an embodiment herein, if the HARQ process is configured with disabled HARQ feedback (for example, for a serving cell that is part of NTN) and is associated with a transmission indicated with a Cell-Radio Network Temporary Identifier (C-RNTI) or a Configured Scheduling-RNTI (CS-RNTI) or a Temporary C-RNTI (T-C-RNTI) or a configured downlink assignment for unicast and if the parameter harq-FeedbackEnablingforSPSactive is configured with a value true and if the transmission is the first transmission on the configured downlink assignment after activation of the configured downlink assignment, the Medium Access Layer (MAC) layer of the UE 100 can instruct the physical layer to generate acknowledgement(s) of the data in this transport block (TB).

[0131] In an embodiment herein, if the HARQ process is configured with disabled HARQ feedback (for example, for a serving cell that is part of NTN) and is associated with a transmission indicated with a C-RNTI or a CS-RNTI or a T-C-RNTI or a configured downlink assignment for unicast and if either harq-FeedbackEnablingforSPSactive is not configured with a value true or the transmission is not the first transmission on the configured downlink assignment after activation of the configured downlink assignment, the MAC layer of the UE 100 can instruct the physical layer to not generate acknowledgement(s) of the data in this TB.

[0132] In an embodiment herein, if the HARQ process is configured with enabled HARQ feedback (for example, for a serving cell that is part of NTN) and is associated with a transmission indicated with a C-RNTI or a CS-RNTI or a T-C-RNTI or a configured downlink assignment for unicast, the MAC layer of the UE 100 can instruct the physical layer to generate acknowledgement(s) of the data in this TB.

[0133] In an embodiment herein (as depicted in FIG. 5), an example MAC specification TS 38.321 for the determination of HARQ feedback generation is provided for addressing the case where HARQ feedback is disabled.

[0134] Example 3:

[0135] 5.3.2.2 HARQ process

[0136] When a transmission takes place for the HARQ process, one or two (in case of downlink spatial multiplexing) TBs and the associated HARQ information are received from the HARQ entity.

[0137] For each received TB and associated HARQ information, the HARQ process shall:

[0138] 1> if the NDI, when provided, has been toggled compared to the value of the previous received transmission corresponding to this TB; or

[0139] 1> if the HARQ process is equal to the broadcast process, and this is the first received transmission for the TB according to the system information schedule indicated by RRC; or

[0140] 1> if the HARQ process is associated with a transmission indicated with a MCCH-RNTI for MBS broadcast, and this is the first received transmission for the TB according to the broadcast MCCH schedule indicated by RRC; or

[0141] 1> if the HARQ process is associated with a transmission indicated with a Multicast MCCH-RNTI for MBS multicast in RRC_INACTIVE, and this is the first received transmission for the TB according to the multicast MCCH schedule indicated by RRC; or

[0142] 1> if the HARQ process is associated with a transmission indicated with a G-RNTI for MBS broadcast, and this is the first received transmission for the TB according to the MTCH schedule indicated by RRC or according to the scheduling indicated by DCI as specified in TS 38.214; or

[0143] 1> if this is the very first received transmission for this TB (i.e. there is no previous NDI for this TB):

[0144] 2> consider this transmission to be a new transmission.

[0145] 1> else:

[0146] 2> consider this transmission to be a retransmission.

[0147] The MAC entity then shall:

[0148] 1> if this is a new transmission:

[0149] 2> attempt to decode the received data.

[0150] 1> else if this is a retransmission:

[0151] 2> if the data for this TB has not yet been successfully decoded:

[0152] 3> instruct the physical layer to combine the received data with the data currently in the soft buffer for this TB and attempt to decode the combined data.

[0153] 1> if the data which the MAC entity attempted to decode was successfully decoded for this TB; or

[0154] 1> if the data for this TB was successfully decoded before:

[0155] 2> if the HARQ process is equal to the broadcast process:

[0156] 3> deliver the decoded MAC PDU to upper layers.

[0157] 2> else if this is the first successful decoding of the data for this TB:

[0158] 3> deliver the decoded MAC PDU to the disassembly and demultiplexing entity.

[0159] 1> else:

[0160] 2> instruct the physical layer to replace the data in the soft buffer for this TB with the data which the MAC entity attempted to decode.

[0161] 1> if the HARQ process is associated with a transmission indicated with a Temporary C-RNTI and the Contention Resolution is not yet successful (see clause 5.1.5); or

[0162] 1> if the HARQ process is associated with a transmission indicated with a MSGB-RNTI and the Random Access procedure is not yet successfully completed (see clause 5.1.4a); or

[0163] 1> if the HARQ process is equal to the broadcast process; or

[0164] 1> if the HARQ process is associated with a transmission indicated with a MCCH-RNTI or a G-RNTI for MBS broadcast; or

[0165] 1> if the HARQ process is associated with a transmission indicated with a Multicast MCCH-RNTI for MBS multicast; or

[0166] 1> if the HARQ process is associated with a transmission indicated with a G-RNTI or a G-CS-RNTI or a configured downlink assignment for MBS multicast and HARQ feedback is disabled for this G-RNTI or G-CS-RNTI or the corresponding G-CS-RNTI, as specified in clause 18 of TS 38.213 [6]; or

[0167] 1> if the HARQ process is associated with a transmission indicated with a G-RNTI or a G-CS-RNTI or a configured downlink assignment for MBS multicast and NACK only HARQ feedback is used for this G-RNTI or G-CS-RNTI or the corresponding G-CS-RNTI and the data for this TB is successfully decoded and the transmission is not the first transmission of PDSCH where the configured downlink assignment was (re-)initialised; or

[0168] 1> if thetimeAlignmentTimer, associated with the TAG containing the Serving Cell on which the HARQ feedback is to be transmitted, is stopped or expired, and the Serving Cell is not configured with two TAGs, and if thecg-SDT-TimeAlignmentTimer, if configured, is not running; or

[0169] 1> if the Serving Cell on which the HARQ feedback is to be transmitted is configured with two TAGs and if thetimeAlignmentTimerof the TAG, associated with the TCI state(s) used for transmitting the HARQ feedback, is stopped or expired:

[0170] 2> not instruct the physical layer to generate acknowledgement(s) of the data in this TB.

[0171] 1> else if the HARQ process is configured with disabled HARQ feedback and is associated with a transmission indicated with a C-RNTI or a CS-RNTI or a T-C-RNTI or a configured downlink assignment for unicast:

[0172] 2> if harq-FeedbackEnablingforSPSactive is configured with a value true and the transmission is the first transmission on the configured downlink assignment after activation of the configured downlink assignment:

[0173] 3> instruct the physical layer to generate acknowledgement(s) of the data in this TB.

[0174] 2> else:

[0175] 3> not instruct the physical layer to generate acknowledgement(s) of the data in this TB.

[0176] 1> else:

[0177] 2> instruct the physical layer to generate acknowledgement(s) of the data in this TB.

[0178] The MAC entity shall ignore NDI received in all downlink assignments on PDCCH for its Temporary C-RNTI when determining if NDI on PDCCH for its C-RNTI has been toggled compared to the value in the previous transmission.

[0179] NOTE: If the MAC entity receives a retransmission with a TB size different from the last TB size signalled for this TB, the UE behavior is left up to UE implementation.

[0180] In an embodiment herein, the multicast HARQ configuration can have precedence over the unicast HARQ configuration (for example, for Non-Terrestrial Network, NTN), when the HARQ process is associated with a transmission indicated with a G-RNTI or a G-CS-RNTI or a configured downlink assignment for MBS multicast.

[0181] In an embodiment herein, the multicast HARQ configuration can have precedence over the unicast HARQ configuration (for example, for Terrestrial Network, TN), when the HARQ process is associated with a transmission indicated with a G-RNTI or a G-CS-RNTI or a configured downlink assignment for MBS multicast.

[0182] In an embodiment herein, HARQ configuration parameters HARQ-feedbackEnabling-disablingperHARQprocess and harq-FeedbackEnablingforSPSactive　can be associated with　the NTN.

[0183] In an embodiment herein, HARQ configuration parameters HARQ-feedbackEnabling-disablingperHARQprocess and harq-FeedbackEnablingforSPSactive　can be associated with　the Terrestrial Network.

[0184] In an embodiment herein, if harq-FeedbackEnablingforSPSactive is set as enabled, the HARQ process is associated with a transmission indicated with a G-RNTI or a G-CS-RNTI or a configured downlink assignment for MBS multicast, and the transmission is the first transmission on the configured downlink assignment after activation of the configured downlink assignment, the MAC entity of the UE 100 can instruct the physical layer to generate acknowledgement(s) of the data in this TB, when at least one of the following conditions is satisfied:

[0185] - The UE is configured for the G-RNTI or G-CS-RNTI by harq-FeedbackEnablerMulticast with a value set to 'enabled'.

[0186] - The UE is provided harq-FeedbackEnablerMulticast with a value set to 'dci-enabler' for a G-RNTI for multicast or a G-CS-RNTI, and the PDSCH receptions are scheduled by multicast DCI format 4_1 associated with the G-RNTI or the G-CS-RNTI.

[0187] - The UE is provided harq-FeedbackEnablerMulticast with a value set to 'dci-enabler' for a G-RNTI for multicast or a G-CS-RNTI, and the PDSCH receptions are scheduled or activated by multicast DCI format 4_2 based on an indication by the multicast DCI format 4_2 associated with the G-RNTI for multicast or the G-CS-RNTI .

[0188] In an embodiment herein, if harq-FeedbackEnablingforSPSactive is set as enabled, the HARQ process is associated with a transmission indicated with a G-RNTI or a G-CS-RNTI or a configured downlink assignment for MBS multicast, and the transmission is the first transmission on the configured downlink assignment after activation of the configured downlink assignment, the MAC entity of the UE 100 can skip instructing the physical layer to generate acknowledgement(s) of the data in this TB, when none of the following conditions are satisfied:

[0189] - The UE is configured for the G-RNTI or G-CS-RNTI by harq-FeedbackEnablerMulticast with a value set to 'enabled'.

[0190] - The UE is provided harq-FeedbackEnablerMulticast with a value set to 'dci-enabler' for a G-RNTI for multicast or a G-CS-RNTI, and the PDSCH receptions are scheduled by multicast DCI format 4_1 associated with the G-RNTI or the G-CS-RNTI.

[0191] - The UE is provided harq-FeedbackEnablerMulticast with a value set to 'dci-enabler' for a G-RNTI for multicast or a G-CS-RNTI, and the PDSCH receptions scheduled or activated by multicast DCI format 4_2 based on an indication by the multicast DCI format 4_2 associated with the G-RNTI for multicast or the G-CS-RNTI.

[0192] In an embodiment herein, if harq-FeedbackEnablingforSPSactive is set as enabled, if the HARQ process is associated with a transmission indicated with a G-RNTI or a G-CS-RNTI or a configured downlink assignment for MBS multicast, and the transmission is for the (multicast) SPS PDSCH release indication by DCI format 4_1 with counter DAI field value of 1, the MAC entity of the UE 100 can instruct the physical layer to generate acknowledgement(s) of the data in this TB.

[0193] In an embodiment herein, if the HARQ process is configured with disabled HARQ feedback (for example, for a serving cell that is part of NTN), if the HARQ process is associated with a transmission indicated with a G-RNTI or a G-CS-RNTI or a configured downlink assignment for MBS multicast, and the transmission is for the (multicast) SPS PDSCH release indication by DCI format 4_1 with counter DAI field value of 1, the MAC entity of the UE 100 can instruct the physical layer to generate acknowledgement(s) of the data in this TB.

[0194] In an embodiment herein, if the HARQ process is configured with disabled HARQ feedback (for example, for a serving cell that is part of NTN), if the HARQ process is associated with a transmission for the (unicast) SPS PDSCH release indication by DCI format 1_0 with counter DAI field value of 1, the MAC entity of the UE 100 can instruct the physical layer to generate acknowledgement(s) of the data in this TB.

[0195] In an embodiment herein, if harq-FeedbackEnablingforSPSactive is set as disabled, if the HARQ process is associated with a transmission for the (unicast) SPS PDSCH release indication by DCI format 1_0 with counter DAI field value of 1, the MAC entity of the UE 100 can instruct the physical layer to generate acknowledgement(s) of the data in this TB.

[0196] In an embodiment herein, if the HARQ process is configured with disabled HARQ feedback (for example, for a serving cell that is part of NTN) and is associated with a transmission indicated with a C-RNTI or a CS-RNTI or a T-CS-RNTI or a configured downlink assignment for unicast and if the transmission is the unicast or PTP retransmission of the PTM transmission of MBS multicast addressed by G-RNTI or G-CS-RNTI or configured downlink assignment of MBS multicast, the MAC entity of the UE 100 can instruct the physical layer to generate acknowledgement(s) of the data in this TB. Further, the MAC entity can set the HARQ-RTT-TimerDL-NTN for the corresponding HARQ process equal to drx-HARQ-RTT-TimerDL plus the latest available UE-gNB RTT value. The MAC entity can also start the HARQ-RTT-TimerDL-NTN for the corresponding HARQ process in the first symbol after the end of the corresponding transmission carrying the DL HARQ feedback.

[0197] In an embodiment herein, if the HARQ process is configured with disabled HARQ feedback (for example, for a serving cell that is part of NTN) and is associated with a transmission indicated with a C-RNTI or a CS-RNTI or a T-CS-RNTI or a configured downlink assignment for unicast and if the transmission is the unicast or PTP retransmission of the PTM transmission of MBS multicast addressed by G-RNTI or G-CS-RNTI or configured downlink assignment of MBS multicast, the MAC entity of the UE 100 can instruct the physical layer to generate acknowledgement(s) of the data in this TB, when at least one of the following conditions are satisfied:

[0198] - The UE is configured for the G-RNTI or G-CS-RNTI by harq-FeedbackEnablerMulticast with a value set to 'enabled'.

[0199] - The UE is provided harq-FeedbackEnablerMulticast with a value set to 'dci-enabler' for a G-RNTI for multicast or a G-CS-RNTI, and the PDSCH receptions are scheduled by multicast DCI format 4_1 associated with the G-RNTI or the G-CS-RNTI.

[0200] - The UE is provided harq-FeedbackEnablerMulticast with a value set to 'dci-enabler' for a G-RNTI for multicast or a G-CS-RNTI, and the PDSCH receptions are scheduled or activated by multicast DCI format 4_2 based on an indication by the multicast DCI format 4_2 associated with the G-RNTI for multicast or the G-CS-RNTI .

[0201] - The UE is provided with a SPS PDSCH release indication by DCI format 4_1 with counter DAI field value of 1.

[0202] Further, the MAC entity can set theHARQ-RTT-TimerDL-NTNfor the corresponding HARQ process equal todrx-HARQ-RTT-TimerDLplus the latest available UE-gNB RTT value. the MAC entity can also start the HARQ-RTT-TimerDL-NTN for the corresponding HARQ process in the first symbol after the end of the corresponding transmission carrying the DL HARQ feedback.

[0203] In an embodiment herein, an example of PTP / unicast transmission for PTM transmission for MBS multicast, determination of HARQ feedback and setting / starting of the NTN timers is provided as shown below:

[0204] Example 4:

[0205] 1> if a DRX group is in Active Time:

[0206] 2> monitor the PDCCH on the Serving Cells in this DRX group as specified in TS 38.213 [6];

[0207] 2> if the PDCCH indicates a DL transmission; or

[0208] 2> if the PDCCH indicates a one-shot HARQ feedback as specified in clause 9.1.4 of TS 38.213 [6]; or

[0209] 2> if the PDCCH indicates a retransmission of HARQ feedback as specified in clause 9.1.5 of TS 38.213 [6]:

[0210] 3> if this Serving Cell is configured withdownlinkHARQ-FeedbackDisabled:

[0211] 4> if the corresponding HARQ process is configured with HARQ feedback enabled or the DL transmission is the retransmission for the PTM transmission for MBS multicast:

[0212] 5> setHARQ-RTT-TimerDL-NTNfor the corresponding HARQ process equal todrx-HARQ-RTT-TimerDLplus the latest available UE-gNB RTT value;

[0213] 5> start theHARQ-RTT-TimerDL-NTNfor the corresponding HARQ process in the first symbol after the end of the corresponding transmission carrying the DL HARQ feedback.

[0214] 3> else:

[0215] 4> start or restart thedrx-HARQ-RTT-TimerDLfor the corresponding HARQ process(es) whose HARQ feedback is reported in the first symbol after the end of the corresponding transmission carrying the DL HARQ feedback.

[0216] In an embodiment herein, an example of PTP / unicast transmission for PTM transmission for MBS multicast, determination of HARQ feedback and setting / starting of the NTN timers is provided as shown below:

[0217] Example 5:

[0218] When DRX is configured, the MAC entity shall:

[0219] 1> if a MAC PDU is received in a configured downlink assignment for unicast:

[0220] 2> if this Serving Cell is configured withdownlinkHARQ-FeedbackDisabled:

[0221] 3> if the corresponding HARQ process is configured with HARQ feedback enabled or the configured downlink assignment for unicast is the retransmission for the PTM transmission for MBS multicast:

[0222] 4> setHARQ-RTT-TimerDL-NTNfor the corresponding HARQ process equal todrx-HARQ-RTT-TimerDLplus the latest available UE-gNB RTT value;

[0223] 4> start theHARQ-RTT-TimerDL-NTNfor the corresponding HARQ process in the first symbol after the end of the corresponding transmission carrying the DL HARQ feedback.

[0224] 2> else:

[0225] 3> start thedrx-HARQ-RTT-TimerDLfor the corresponding HARQ process in the first symbol after the end of the corresponding transmission carrying the DL HARQ feedback.

[0226] 2> stop thedrx-RetransmissionTimerDLfor the corresponding HARQ process;

[0227] 2> stop thedrx-RetransmissionTimerDL-PTMfor the corresponding HARQ process.

[0228] FIGs. 2A and 2B illustrate the determination for the HARQ feedback generation for service data on NTN through MBS multicast in at least one serving cell that is part of the NTN. Consider that the UE is receiving service data for NTN through MBS multicast on at least one serving cell that is part of the NTN. In step 201, the processing module 101 checks if the HARQ process is configured with disabled HARQ feedback (for example, for a serving cell that is part of the NTN), and is not associated with a transmission indicated with a G-RNTI or a G-CS-RNTI or a configured downlink assignment for MBS multicast.

[0229] If the HARQ process is configured with disabled HARQ feedback (for example, for a serving cell that is part of the NTN), and is not associated with a transmission indicated with a G-RNTI or a G-CS-RNTI or a configured downlink assignment for MBS multicast, in step 202, the processing module 101 further checks if harq-FeedbackEnablingforSPSactive is configured with the value 'true' and the transmission is the first transmission on the configured downlink assignment. If harq-FeedbackEnablingforSPSactive is configured with the value 'true' and the transmission is the first transmission on the configured downlink assignment, in step 203, the MAC layer 100A instructs the physical layer to generate acknowledgements of the data in this TB. If harq-FeedbackEnablingforSPSactive is not configured with the value 'true' and / or the transmission is not the first transmission on the configured downlink assignment, in step 204, the MAC layer 100A does not instruct the physical layer to generate acknowledgements of the data in this TB.

[0230] If the HARQ process is not configured with disabled HARQ feedback (for example, for a serving cell that is part of the NTN), and / or is associated with a transmission indicated with a G-RNTI or a G-CS-RNTI or a configured downlink assignment for MBS multicast, in step 205, the processing module 101 determines the HARQ feedback generation, in accordance with a configuration parameter harq-FeedbackEnablerMulticast. In step 206, the processing module 101 can check if the harq-FeedbackEnablerMulticast is set as enabled, or set as DCI-enabler, and DCI indicates providing HARQ feedback. If the harq-FeedbackEnablerMulticast is set as enabled, or set as DCI-enabler, and DCI indicates providing HARQ feedback, in step 203, the MAC layer 100A instructs the physical layer to generate acknowledgements of the data in this TB. If the harq-FeedbackEnablerMulticast is not set as enabled, and / or not set as DCI-enabler, and DCI does not indicate providing HARQ feedback, in step 204, the MAC layer 100A does not instruct the physical layer to generate acknowledgements of the data in this TB. The various actions in method 200 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed in FIGs. 2A and 2B may be omitted.

[0231] FIG. 3 is a flowchart depicting the process of the UE managing the HARQ feedback in the NTN. In step 301, the processing module 101 checks the first condition and the second condition. The first condition comprises checking if a HARQ process is configured with disabled HARQ feedback, and the HARQ process is not associated with a transmission indicated with one of G-RNTI; and G-CS-RNTI. The second condition comprises checking if a configured downlink assignment for Multicast and Broadcast Services (MBS) multicast; and a parameter harq-FeedbackEnablingforSPSactive in a Radio Resource Control (RRC) configuration is configured with a value 'true', and the transmission is a first transmission on a configured downlink assignment after activation of a configured downlink assignment. If both the first and second conditions are satisfied, in step 302, the MAC layer 100A instructs the physical layer 100B to generate at least one acknowledgement of data in a transport block (TB) in the transmission. If at least one of the first condition, or the second condition are not satisfied, in step 303, the MAC layer 100A instructs the physical layer 100 to not generate at least one acknowledgement of data in the TB in the transmission. In an embodiment herein, the generated acknowledgement can be the positive acknowledgement (ACK) (when data in the TB has been successfully decoded), or a negative acknowledgment (NACK) (when data in the TB has not been successfully decoded). The various actions in method 300 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed in FIG. 3 may be omitted.

[0232] FIG. 4 is a flowchart depicting the process of managing NTN operations for MBS multicast in an RRC_INACTIVE state. In step 401, the processing module 101 checks for the third, fourth, and fifth conditions. The third condition comprises checking if drx-HARQ-RTT-TimerDL-PTM has been configured for multicast in RRC_INACTIVE for the UE 100. The fourth condition comprises checking if the UE supports ptm-RetransmissionInactive. The fifth condition comprises checking if PDCCH is indicated on a NTN. If the third, fourth, and fifth conditions are satisfied, in step 402, the processing module 101 sets HARQ-RTT-TimerDL-NTN for the HARQ process equal to a sum of a drx-HARQ-RTT-TimerDL, and a latest available UE-gNB RTT value. In step 403, the processing module 101 further starts a drx-HARQ-RTT-TimerDL-PTM-NTN for the HARQ process in the first symbol after the end of the multicast transmission. The various actions in method 400 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed in FIG. 4 may be omitted.

[0233] FIG. 5 is a flowchart illustrating the determination for the HARQ feedback generation for service data on NTN through MBS multicast in at least one serving cell that is part of the NTN, wherein PTP retransmission for MBS multicast transmission is performed. In step 501, the UE 100 receives service data for NTN through MBS multicast on at least one serving cell that is part of the NTN. In step 502, the UE 100 checks if a sixth condition is satisfied. The sixth condition can comprise checking if the HARQ process configured with disabled HARQ feedback, is associated with a C-RNTI or a CS-RNTI or a T-C-RNTI or a configured downlink assignment, and the transmission is a unicast or PTP retransmission of the PTM transmission of MBS multicast addressed by G-RNTI or G-CS-RNTI or configured downlink assignment of MBS multicast. If the sixth condition is not satisfied, in step 503, the UE 100 does not instruct the physical layer to generate acknowledgement(s) of the data in this TB. If the sixth condition is satisfied, in step 504, the UE 100 instructs the physical layer to generate acknowledgement(s) of the data in this TB. The various actions in method 500 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed in FIG. 5 may be omitted.

[0234] 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.

[0235] The embodiments disclosed herein describe methods and systems for managing Hybrid Automatic Repeat Request (HARQ) feedback in a Non-Terrestrial Network (NTN). 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 for example, 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 for example, hardware means like for example, an ASIC, or a combination of hardware and software means, for example, 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, for example, using a plurality of CPUs.

[0236] 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 embodiments and examples, those skilled in the art will recognize that the embodiments and examples disclosed herein can be practiced with modification within the scope of the embodiments as described herein.

Claims

1.A method performed by a User Equipment (UE) in a wireless communication system, the method comprising:identifying that a transmission takes place for in a Hybrid Automatic Repeat Request (HARQ) process;in case that the HARQ process is configured with disabled HARQ feedback and is not associated with a transmission indicated with a Group-Radio Network Temporary Identifier (G-RNTI) or a Group-Configured Scheduling-RNTI (G-CS-RNTI) or a configured downlink assignment for Multicast and Broadcast Services (MBS) multicast, identifying whether a parameterharq-FeedbackEnablingforSPSactiveis configured with a value true and the transmission is a first transmission on the configured downlink assignment after activation of the configured downlink assignment;in case that the parameterharq-FeedbackEnablingforSPSactiveis configured with the value true and the transmission is the first transmission on the configured downlink assignment after activation of the configured downlink assignment, instructing, by a Medium Access Control (MAC) layer of the UE, a physical layer of the UE to generate at least one acknowledgement of data in a transport block (TB); andin case that either the parameterharq-FeedbackEnablingforSPSactiveis not configured with the value true or the transmission is not the first transmission on the configured downlink assignment after activation of the configured downlink assignment, determining, by the MAC layer, not to instruct the physical layer to generate the at least one acknowledgement of data in the TB.2.The method of claim 1, further comprising:in case that the HARQ process is associated with a transmission indicated with a Temporary Cell-Radio Network Temporary Identifier (C-RNTI) and a contention resolution is not successful, determining, by the MAC layer, not to instruct the physical layer to generate the at least one acknowledgement of data in the TB.3.The method of claim 1, further comprising:in case that the HARQ process is associated with a transmission indicated with a Temporary Cell-Radio Network Temporary Identifier (C-RNTI) and a contention resolution is not successful, determining, by the MAC layer, not to instruct the physical layer to generate the at least one acknowledgement of data in the TB.4.The method of claim 1, further comprising:in case that the HARQ process is equal to a broadcast process, determining, by the MAC layer, not to instruct the physical layer to generate the at least one acknowledgement of data in the TB.5.The method of claim 1, further comprising:in case that HARQ process is associated with a transmission indicated with a MBS Control Channel-Radio Network Temporary Identifier (MCCH-RNTI) or a Group-Radio Network Temporary Identifier (G-RNTI) for MBS broadcast, determining, by the MAC layer, not to instruct the physical layer to generate the at least one acknowledgement of data in the TB.6.The method of claim 1, further comprising:in case that the HARQ process is associated with a transmission indicated with the G-RNTI or the G-CS-RNTI or the configured downlink assignment for MBS multicast and HARQ feedback is disabled for the G-RNTI or the G-CS-RNTI or the corresponding G-CS-RNTI, determining, by the MAC layer, not to instruct the physical layer to generate the at least one acknowledgement of data in the TB.7.The method of claim 1, further comprising:in case that the HARQ process is associated with a transmission indicated with the G-RNTI or the G-CS-RNTI or the configured downlink assignment for MBS multicast and negative acknowledgment (NACK) only HARQ feedback is used for the G-RNTI or the G-CS-RNTI or the corresponding G-CS-RNTI and the data for the TB is successfully decoded and the transmission is not the first transmission of Physical Downlink Shared Channel (PDSCH) where the configured downlink assignment was initialised, determining, by the MAC layer, not to instruct the physical layer to generate the at least one acknowledgement of data in the TB.8.The method of claim 1, further comprising:in case that a parametertimeAlignmentTimer, associated with a Timing Advance Group (TAG) containing a Serving Cell on which the HARQ feedback is to be transmitted, is stopped or expired and in case that a parametercg-SDT-TimeAlignmentTimeris not running, determining, by the MAC layer, not to instruct the physical layer to generate the at least one acknowledgement of data in the TB.9.A user equipment (UE) comprising:at least one transceiver;at least one processor communicatively coupled to the at least one transceiver; andat least one memory, communicatively coupled to the at least one processor, storing instructions executable by the at least one processor individually or in any combination to cause the UE to:identify that a transmission takes place for in a Hybrid Automatic Repeat Request (HARQ) process,in case that the HARQ process is configured with disabled HARQ feedback and is not associated with a transmission indicated with a Group-Radio Network Temporary Identifier (G-RNTI) or a Group-Configured Scheduling-RNTI (G-CS-RNTI) or a configured downlink assignment for Multicast and Broadcast Services (MBS) multicast, identify whether a parameterharq-FeedbackEnablingforSPSactiveis configured with a value true and the transmission is a first transmission on the configured downlink assignment after activation of the configured downlink assignment,in case that the parameterharq-FeedbackEnablingforSPSactiveis configured with the value true and the transmission is the first transmission on the configured downlink assignment after activation of the configured downlink assignment, instruct, by a Medium Access Control (MAC) layer of the UE, a physical layer of the UE to generate at least one acknowledgement of data in a transport block (TB), andin case that either the parameterharq-FeedbackEnablingforSPSactiveis not configured with the value true or the transmission is not the first transmission on the configured downlink assignment after activation of the configured downlink assignment, determine, by the MAC layer, not to instruct the physical layer to generate the at least one acknowledgement of data in the TB.10.The UE of claim 9, wherein the instructions executable by the at least one processor individually or in any combination further cause the UE to:in case that the HARQ process is associated with a transmission indicated with a Temporary Cell-Radio Network Temporary Identifier (C-RNTI) and a contention resolution is not successful, determining, by the MAC layer, not to instruct the physical layer to generate the at least one acknowledgement of data in the TB.11.The UE of claim 9, wherein the instructions executable by the at least one processor individually or in any combination further cause the UE to:in case that the HARQ process is associated with a transmission indicated with a Temporary Cell-Radio Network Temporary Identifier (C-RNTI) and a contention resolution is not successful, determining, by the MAC layer, not to instruct the physical layer to generate the at least one acknowledgement of data in the TB.12.The UE of claim 9, wherein the instructions executable by the at least one processor individually or in any combination further cause the UE to:in case that the HARQ process is equal to a broadcast process, determining, by the MAC layer, not to instruct the physical layer to generate the at least one acknowledgement of data in the TB.13.The UE of claim 9, wherein the instructions executable by the at least one processor individually or in any combination further cause the UE to:in case that HARQ process is associated with a transmission indicated with a MBS Control Channel-Radio Network Temporary Identifier (MCCH-RNTI) or a Group-Radio Network Temporary Identifier (G-RNTI) for MBS broadcast, determining, by the MAC layer, not to instruct the physical layer to generate the at least one acknowledgement of data in the TB.14.The UE of claim 9, wherein the instructions executable by the at least one processor individually or in any combination further cause the UE to:in case that the HARQ process is associated with a transmission indicated with the G-RNTI or the G-CS-RNTI or the configured downlink assignment for MBS multicast and HARQ feedback is disabled for the G-RNTI or the G-CS-RNTI or the corresponding G-CS-RNTI, determining, by the MAC layer, not to instruct the physical layer to generate the at least one acknowledgement of data in the TB.15.The UE of claim 9, wherein the instructions executable by the at least one processor individually or in any combination further cause the UE to:in case that:the HARQ process is associated with a transmission indicated with the G-RNTI or the G-CS-RNTI or the configured downlink assignment for MBS multicast and negative acknowledgment (NACK) only HARQ feedback is used for the G-RNTI or the G-CS-RNTI or the corresponding G-CS-RNTI and the data for the TB is successfully decoded and the transmission is not the first transmission of Physical Downlink Shared Channel (PDSCH) where the configured downlink assignment was initialised, ora parametertimeAlignmentTimer, associated with a Timing Advance Group (TAG) containing a Serving Cell on which the HARQ feedback is to be transmitted, is stopped or expired and in case that a parametercg-SDT-TimeAlignmentTimeris not running,determining, by the MAC layer, not to instruct the physical layer to generate the at least one acknowledgement of data in the TB.

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