Feed back expansion for multicast-broadcast service

Abstract

To provide a hybrid automatic retransmission request (HARQ) feed back transmission method.SOLUTION: A system, a method, and a device for a mobile communication are provided. A user terminal (UE) receives a multicast-broadcast service (MBS) transport block, and the UE is corresponded to a defined state. The defined state can be made to a RRC non-active or an idle state. The UE determines a transmission of a hybrid automatic retransmission request (HARQ) feed back to the MBS transport block to be received. Sequentially, the UE transmits an instruction of the HARQ feed back.SELECTED DRAWING: Figure 18

Description

[Technical field]

[0001] The present disclosure relates to methods for Hybrid Automatic Repeat Request (HARQ) feedback transmission and methods for Channel State Information (CSI) feedback reporting. [Background technology]

[0002] Generally described, computing devices and communication networks can be used to exchange information. In a typical application, a computing device can request / transmit data to another computing device via a communication network. More specifically, computing devices can use a wireless communication network to exchange information or establish a communication channel.

[0003] A wireless communications network may include a wide variety of devices that include components for accessing the wireless communications network or that access the wireless communications network, and such devices may utilize the wireless communications network to facilitate interaction with other devices that can access the wireless communications network or to facilitate interaction over the wireless communications network with devices that utilize other communications networks. Summary of the Invention

[0004] Some embodiments of the present disclosure provide a method for hybrid automatic repeat request (HARQ) feedback transmission, including receiving a Multicast Broadcast Service (MBS) transport block from a base station via a downlink data channel, determining that a received power level of a reference signal is greater than a predefined threshold, and transmitting HARQ feedback associated with the received MBS transport block.

[0005] Some embodiments of the present disclosure provide a method for hybrid automatic repeat request (HARQ) feedback transmission, the method including: receiving, by a UE, a Multicast Broadcast Service (MBS) transport block corresponding to a defined state; determining, by the UE, to transmit HARQ feedback for the received MBS transport block; and transmitting the HARQ feedback using a random access process based on whether the UE is in the defined state.

[0006] In some embodiments of the present disclosure, a method for channel state information (CSI) feedback reporting is provided, which includes receiving a logical control channel associated with a multicast broadcast service (MBS) over a downlink data channel, the logical control channel carrying control information including CSI configuration parameters for CSI measurements and CSI reporting, the CSI reporting being associated with the MBS, measuring, by a UE, one or more reference signals based on the CSI configuration parameters, and transmitting a CSI report based on the measured one or more reference signals and based on the CSI configuration parameters.

[0007] In some embodiments of the present disclosure, a method for channel state information (CSI) feedback reporting is provided, the method including receiving CSI configuration parameters, the CSI configuration parameters including a first CSI configuration parameter associated with a multicast broadcast service (MBS) and a second CSI configuration parameter associated with a unicast service. measuring one or more first reference signals based on the first CSI configuration parameters; measuring one or more second reference signals based on the second CSI configuration parameters; transmitting a first CSI report associated with the one or more MBSs based on the measurements of the first reference signals; and transmitting a second CSI report associated with the one or more unicast services based on the measurements of the second reference signals.

[0008] In some embodiments of the present disclosure, an apparatus for a mobile communication network is provided, the apparatus including a memory storing instructions and a processor configured to execute the instructions, which performs the following operations: receive channel state information (CSI) configuration parameters, the CSI configuration parameters including a first CSI configuration parameter associated with a multicast broadcast service (MBS) and a second CSI configuration parameter associated with a unicast service, measure one or more first reference signals based on the first CSI configuration parameters, measure one or more second reference signals based on the second CSI configuration parameters, transmit a first CSI report associated with the one or more MBSs based on the measurement of the first reference signals, and transmit a second CSI report associated with the one or more unicast services based on the measurement of the second reference signals.

[0009] In some embodiments of the present disclosure, a system for mobile communications is provided, including a base station configured to transmit channel state information (CSI) configuration parameters to a user equipment (UE), the CSI configuration parameters including a first CSI configuration parameter associated with a multicast broadcast service (MBS) and a second CSI configuration parameter associated with a unicast service, and the UE configured to measure one or more first reference signals based on the first CSI configuration parameter and measure one or more second reference signals based on the second CSI configuration parameter.

[0010] In some embodiments of the present disclosure, a non-transitory computer-readable medium is provided. The non-transitory computer-readable medium stores a set of instructions executable by at least one processor of a device in a mobile communication system to perform a method. The method includes receiving channel state information (CSI) configuration parameters, the CSI configuration parameters including a first CSI configuration parameter associated with a multicast broadcast service (MBS) and a second CSI configuration parameter associated with a unicast service, measuring one or more first reference signals based on the first CSI configuration parameters, measuring one or more second reference signals based on the second CSI configuration parameters, transmitting a first CSI report associated with the one or more MBSs based on the measurement of the first reference signal, and transmitting a second CSI report associated with the one or more unicast services based on the measurement of the second reference signal.

[0011] In some embodiments of the present disclosure, a non-transitory computer-readable medium is provided. The non-transitory computer-readable medium stores a set of instructions executable by at least one processor of a device in a mobile communication system to perform a method. The method includes transmitting channel state information (CSI) configuration parameters including a first CSI configuration parameter associated with a multicast broadcast service (MBS) and a second CSI configuration parameter associated with a unicast service, and the UE is configured to measure one or more first reference signals based on the first CSI configuration parameter and measure one or more second reference signals based on the second CSI configuration parameter. [Brief description of the drawings]

[0012] [Figure 1] 1 illustrates an example of a system for mobile communications in accordance with some aspects of one or more exemplary embodiments of the present disclosure. [Diagram 2]2A and 2B illustrate example radio protocol stacks for a user plane in accordance with some aspects of one or more example embodiments of the present disclosure. [Diagram 3] 3A, 3B, and 3C illustrate example mappings between logical channels and transport channels in the downlink in accordance with some aspects of one or more example embodiments of the present disclosure. [Figure 4] 4A, 4B, and 4C illustrate example mappings between transport channels and physical channels in the downlink in accordance with some aspects of one or more example embodiments of the present disclosure. [Diagram 5] 5A, 5B, 5C, and 5D illustrate example radio protocol stacks for NR sidelink communications in accordance with some aspects of one or more exemplary embodiments of the present disclosure. [Figure 6] 1 illustrates exemplary physical signals in the downlink, uplink, and sidelink in accordance with some aspects of one or more exemplary embodiments of the present disclosure. [Figure 7] 1 illustrates examples of Radio Resource Control (RRC) states and transitions between different RRC states, in accordance with some aspects of one or more example embodiments of the present disclosure. [Figure 8] 1 illustrates an example frame structure and physical resources in accordance with some aspects of one or more example embodiments of the present disclosure. [Figure 9] 1 illustrates example component carrier configurations in different carrier aggregation scenarios in accordance with some aspects of one or more example embodiments of the present disclosure. [Figure 10] 1 illustrates an exemplary bandwidth portion configuration and switching in accordance with some aspects of one or more exemplary embodiments of the present disclosure. [Figure 11] 1 illustrates an exemplary four-step contention-based and contention-free random access process in accordance with some aspects of one or more exemplary embodiments of the present disclosure. [Figure 12]1 illustrates an example two-step contention-based and contention-free random access process in accordance with some aspects of one or more example embodiments of the present disclosure. [Figure 13] 1 illustrates an example time and frequency structure of a synchronization signal and a Physical Broadcast Channel (PBCH) block (SSB), in accordance with some aspects of one or more example embodiments of the present disclosure. [Figure 14] 1 illustrates an example of an SSB burst transmission according to some aspects of one or more exemplary embodiments of the present disclosure. [Figure 15] 1 illustrates example components of a user terminal and a base station for transmission and / or reception in accordance with some aspects of one or more example embodiments of the present disclosure. [Figure 16] 1 illustrates an example process according to some aspects of one or more example embodiments of the present disclosure. [Figure 17] 1 illustrates an example process according to some aspects of one or more example embodiments of the present disclosure. [Figure 18] 1 illustrates an example process according to some aspects of one or more example embodiments of the present disclosure. [Figure 19] 1 illustrates an example process according to some aspects of one or more example embodiments of the present disclosure. [Figure 20] 1 illustrates an example process according to some aspects of one or more example embodiments of the present disclosure. [Figure 21] 1 illustrates an example process according to some aspects of one or more example embodiments of the present disclosure. [Figure 22] 1 illustrates an example process according to some aspects of one or more example embodiments of the present disclosure. [Figure 23] 1 illustrates an example process according to some aspects of one or more example embodiments of the present disclosure. [Figure 24] 1 illustrates an example process according to some aspects of one or more example embodiments of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The following disclosure provides many different embodiments or examples for implementing different features of the provided subject matter. To simplify the disclosure, specific examples of configurations are described below. These are merely examples and are not intended to be limiting.

[0014] Terms such as "first", "second", etc. may be used herein to describe various elements, but these elements should not be limited by these terms. These terms are used to distinguish one element from another. For example, a first element can be referred to as a second element, and similarly, a second element can be referred to as a first element, without departing from the scope of the embodiment.

[0015] 1 illustrates an example of a mobile communication system 100 according to some aspects of one or more exemplary embodiments of the present disclosure. The mobile communication system 100 may be operated by a wireless communication system operator, such as a Mobile Network Operator (MNO), a private network operator, a Multiple System Operator (MSO), an Internet of Things (IoT) network operator, etc., and may provide services such as voice, data (e.g., wireless Internet access), messaging, vehicular communication services such as vehicle-to-everything (V2X) communication services, safety services, mission-critical services, IoT, Industrial IoT (IIOT), and other services in residential, commercial, or industrial environments.

[0016] The mobile communication system 100 may enable various types of applications having different requirements in terms of latency, reliability, throughput, etc. Examples of supported applications include enhanced mobile broadband (eMBB), ultra-reliable low-latency communications (URLLC), and massive machine-type communications (mMTC). eMBB can support stable connections with high peak data rates, as well as moderate rates for cell-edge users. URLLC can support applications with stringent requirements in terms of latency and reliability, and moderate requirements in terms of data rates. An exemplary mMTC application includes a network of vast numbers of IoT devices that are only sporadically active and transmit small data payloads.

[0017] The mobile communication system 100 may include a radio access network (RAN) portion and a core network portion. The example shown in FIG. 1 illustrates a Next Generation RAN (NG-RAN) 105 and a 5G Core Network (5GC) 110 as examples of the RAN and the core network, respectively. Other examples of the RAN and the core network may be implemented without departing from the scope of the present disclosure. Other examples of the RAN include an Evolved Universal Terrestrial Radio Access Network (EUTRAN), a Universal Terrestrial Radio Access Network (UTRAN), and the like. Other examples of the core network include an Evolved Packet Core (EPC), a UMTS Core Network (UCN), and the like. The RAN implements a radio access technology (RAT) and resides between a user equipment (UE) 125 (e.g., UE 125A-UE 125E) and the core network. Examples of such RATs include New Radio (NR), Long Term Evolution (LTE), also known as Evolved Universal Terrestrial Radio Access (EUTRA), Universal Mobile Telecommunication System (UMTS), and the like. The RAT of the exemplary system 100 for mobile communications may be NR. The core network exists between the RAN and one or more external networks (e.g., data networks) and provides mobility management, authentication, session management, bearer security, and the like. The NG-RAN 105 is responsible for functions such as setting up the UE 125 and applying different Quality of Service (QoS). The functional layer between the UE 125 and the RAN (e.g., the NG-RAN 105) may be referred to as an Access Stratum (AS), and the functional layer between the UE 125 and the core network (e.g., the 5GC 110) may be referred to as a Non-Access Stratum (NAS).

[0018] The UE 125 may include wireless transmitting and receiving components for communication with one or more nodes in the RAN, one or more relay nodes, or one or more other UEs, etc. Examples of the UE 125 include, but are not limited to, a smartphone, a tablet, a laptop, a computer, a wireless transmitting and / or receiving unit in a vehicle, a V2X or vehicle-to-vehicle (V2V) device, a wireless sensor, an IoT device, an IIOT device, etc. Other names may be used for the UE 125, such as a mobile station (MS), terminal equipment, terminal node, client device, mobile device, etc. Still further, the UE 125 may also include components or subcomponents integrated into other devices, such as a vehicle, to provide wireless communication capabilities with nodes in the RAN, other UEs, satellite communications, as described herein. Such other devices may have other functions or functions in addition to wireless communications. Thus, reference to a UE may include individual components that enable wireless communications as well as an entire device incorporating components for enabling wireless communications.

[0019] The RAN may include nodes (e.g., base stations) for communication with UEs. For example, the NG-RAN 105 of the mobile communication system 100 may include nodes for communication with the UEs 125. Different names may be used for the RAN nodes depending, for example, on the RAT used for the RAN. The RAN nodes may be referred to as Node Bs (NBs) in a RAN using a UMTS RAT. The RAN nodes may be referred to as Evolved Node Bs (eNBs) in a RAN using an LTE / EUTRA RAT. In the illustrative example of the mobile communication system 100 of FIG. 1, the nodes of the NG-RAN 105 may be either Next Generation Node Bs (gNBs) 115 (e.g., gNBs 115A, gNBs 115B) or Next Generation Evolved Node Bs (ng-eNBs) 120 (e.g., ng-eNBs 120A, ng-eNBs 120B). In this specification, the terms base station, RAN node, gNB, and ng-eNB may be used interchangeably. The gNB 115 may provide NR user plane and control plane protocol terminations towards the UE 125. The ng-eNB 120 may provide E-UTRA user plane and control plane protocol terminations towards the UE 125. The interface between the gNB 115 and the UE 125 or between the ng-eNB 120 and the UE 125 may be referred to as a Uu interface. The Uu interface may be established with a user plane protocol stack and a control plane protocol stack. For the Uu interface, the direction from the base station (e.g., gNB 115 or ng-eNB 120) to the UE 125 may be referred to as a downlink, and the direction from the UE 125 to the base station (e.g., gNB 115 or ng-eNB 120) may be referred to as an uplink.

[0020] The gNB 115 and the ng-eNB 120 may be interconnected with each other by an Xn interface. The Xn interface may include an Xn User Plane (Xn-U) interface and an Xn Control Plane (Xn-C) interface. The transport network layer of the Xn-U interface may be built on Internet Protocol (IP) transport, and General Packet Radio Service (GPRS) Tunneling Protocol (GTP) may be used on top of User Datagram Protocol (UDP) / IP to carry user plane protocol data units (PDUs). Xn-U may provide non-guaranteed delivery of user plane PDUs and may support data forwarding and flow control. The transport network layer of the Xn-C interface may be built on Stream Control Transport Protocol (SCTP) on top of IP. The application layer signaling protocol may be XnAP (Xn Application Layer Protocol). The SCTP layer can provide guaranteed delivery of application layer messages. At the transport IP layer, point-to-point transmission can be used to deliver signaling PDUs. The Xn-C interface can support Xn interface management, UE mobility management including context transfer and RAN paging, and dual connectivity.

[0021] The gNB 115 and the ng-eNB 120 may also be connected to the 5GC 110 using an NG interface, more specifically to an Access and Mobility Management Function (AMF) 130 (e.g., AMF 130A, AMF 130B) of the 5GC 110 using an NG-C interface, and to a User Plane Function (UPF) 135 (e.g., UPF 135A, UPF 135B) of the 5GC 110 using an NG-U interface. The transport network layer of the NG-U interface may be built on IP transport, and the GTP protocol may be used on top of UDP / IP to carry user plane PDUs between the NG-RAN nodes (e.g., gNB 115 or ng-eNB 120) and the UPF 135. The NG-U may provide non-guaranteed delivery of user plane PDUs between the NG-RAN nodes and the UPF. The transport network layer of the NG-C interface may be built on IP transport. SCTP may be added on top of IP for reliable transport of signaling messages. The application layer signaling protocol may be referred to as NGAP (NG Application Protocol). The SCTP layer may provide guaranteed delivery of application layer messages. For transport, IP layer point-to-point transmission may be used to deliver signaling PDUs. The NG-C interface may provide the following functions: NG interface management, UE context management, UE mobility management, transport of NAS messages, paging, PDU session management, configuration transfer, and alert message transmission.

[0022] The gNB 115 or ng-eNB 120 performs the following functions: radio bearer control, radio admission control, connection mobility control, radio resource management functions such as dynamic allocation of resources (e.g., scheduling) to UEs in both uplink and downlink, IP and Ethernet header compression, data encryption and integrity protection, selection of an AMF at UE attachment when routing to an AMF cannot be determined from information provided by the UE, routing of user plane data to UPF(s), routing of control plane information to AMF, connection setup and release, scheduling and transmission of paging messages (e.g., P2P messages originating from the AMF, etc.), and transmission of UE-originated AMF messages (e.g., P2P messages originating from the AMF). The 5G LTE-RPC can host one or more of the following: scheduling and transmission of system broadcast information (including LTE-RPC), measurement and measurement reporting configuration for mobility and scheduling, transport level packet marking in the uplink, session management, support for network slicing, QoS flow management and mapping to data radio bearers, support for UE in RRC inactive state, delivery function for NAS messages, radio access network sharing, dual connectivity, tight interworking between NR and E-UTRA, and maintaining security and radio configuration for User Plane 5G System (5GS) Cellular IoT (CIoT) optimization.

[0023] The AMF 130 performs one of the following functions: NAS signaling termination, NAS signaling security, AS security control, CN inter-node signaling for mobility between 3GPP access networks, idle mode UE reachability (including control and execution of paging retransmissions), registration area management, support for intra-system and inter-system mobility, access authentication, access authorization including checking roaming rights, mobility management control (subscription and policy), support for network slicing, Session Management Function (SMF) selection, 5GS CIoT optimization selection or Can host multiple.

[0024] The UPF 135 may host one or more of the following functions: anchor point for intra / inter-RAT mobility (when applicable), external PDU session point of interconnection to data network, packet routing and forwarding, user plane part of packet inspection and policy rule enforcement, traffic usage reporting, uplink classifier to support routing of traffic flows to data network, branching point to support multi-homed PDU sessions, QoS processing for user plane, e.g., packet filtering, gating, UL / DL rate enforcement, uplink traffic validation (service data flow (SDF) to QoS flow mapping), downlink packet buffering, and downlink data notification triggering.

[0025] As shown in FIG. 1, the NG-RAN 105 may support a PC5 interface between two UEs 125 (e.g., UE 125A and UE 125B). In the PC5 interface, the direction of communication between the two UEs (e.g., from UE 125A to UE 125B or vice versa) may be referred to as a sidelink. Regardless of which RRC state the UE is in, sidelink transmission and reception over the PC5 interface may be supported when the UE 125 is within the coverage of the NG-RAN 105 and when the UE 125 is out of the coverage of the NG-RAN 105. Support for V2X services over the PC5 interface may be provided by NR sidelink communication and / or V2X sidelink communication.

[0026] PC5-S signaling may be used for unicast link establishment with direct communication request / accept messages. A UE may self-assign its source layer 2 ID for a PC5 unicast link, for example based on the V2X service type. During the unicast link establishment procedure, a UE may send its source layer 2 ID for a PC5 unicast link to a peer UE, for example, a UE for which a destination ID was received from a higher layer. The source layer 2 ID and destination layer 2 ID pair may uniquely identify a unicast link. The receiving UE may verify that the destination ID belongs to it and may accept the unicast link establishment request from the source UE. During the PC5 unicast link establishment procedure, PC5-RRC procedures on the access stratum may be invoked for UE sidelink context establishment as well as for AS layer configuration, capability exchange, etc. PC5-RRC signaling may enable UE capabilities and AS layer configuration, such as sidelink radio bearer configuration, to be exchanged between a pair of UEs for which a PC5 unicast link is established.

[0027] NR sidelink communication can support one of three types of transmission modes (e.g., unicast transmission, groupcast transmission, and broadcast transmission) for a pair of source and destination layer 2 IDs in an AS. The unicast transmission mode may be characterized by the support of one PC5-RRC connection between peer UEs for the pair, the transmission and reception of control information and user traffic between peer UEs in the sidelink, the support of sidelink HARQ feedback, the support of sidelink transmit power control, the support of RLC acknowledged mode (AM), and the detection of radio link failure for the PC5-RRC connection. The groupcast transmission may be characterized by the transmission and reception of user traffic between UEs belonging to a group in the sidelink and the support of sidelink HARQ feedback. The broadcast transmission may be characterized by the transmission and reception of user traffic between UEs in the sidelink.

[0028] The source Layer 2 ID, destination Layer 2 ID, and PC5 link identifier are used for NR sidelink communication. The source layer 2 ID may be a link layer identity that identifies a device or group of devices that is the recipient of the sidelink communication frame. The destination layer 2 ID may be a link layer identity that identifies a device that originates the sidelink communication frame. In some examples, the source layer 2 ID and the destination layer 2 ID may be assigned by a management function in the core network. The source layer 2 ID may identify the sender of the data in the NR sidelink communication. The source layer 2 ID may be 24 bits long and may be split into two bit strings in the medium access control (MAC) layer. One bit string may be the LSB portion (8 bits) of the source layer 2 ID and may be forwarded to the sender's physical layer. This may identify the source of the intended data in the sidelink control information and may be used for packet filtering at the receiver's physical layer, and the second bit string may be the MSB portion (16 bits) of the source layer 2 ID and may be carried in the MAC header. This may be used for packet filtering at the receiver's MAC layer. The destination layer 2 ID may identify the target of the data in the NR sidelink communication. For NR sidelink communication, the destination layer 2 ID may be 24 bits long and may be split into two bit strings at the MAC layer. One bit string may be the LSB part (16 bits) of the destination layer 2 ID and may be forwarded to the sender's physical layer. This may identify the target of the intended data in the sidelink control information and may be used for packet filtering at the receiver's physical layer, and the second bit string may be the MSB part (8 bits) of the destination layer 2 ID and may be carried in the MAC header. This may be used for packet filtering at the receiver's MAC layer. The PC5 link identifier may uniquely identify a PC5 unicast link in the UE for the lifetime of the PC5 unicast link. The PC5 link identifier may be used to indicate the PC5 unicast link on which a sidelink radio link failure (RLF) declaration has been made and the PC5-RRC connection has been released.

[0029] 2A and 2B illustrate example radio protocol stacks for the user plane and control plane, respectively, in accordance with some aspects of one or more example embodiments of the present disclosure. As shown in FIG. 2A, the protocol stack for the user plane of the Uu interface (between the UE 125 and the gNB 115) includes Service Data Adaptation Protocol (SDAP) 201 and SDAP 211, Packet Data Convergence Protocol (PDCP) 202 and PDCP 212, Radio Link Control (RLC) 203 and RLC 213, MAC 204 and MAC 214 sublayers of Layer 2, and Physical (PHY) 205 and PHY 215 layers (Layer 1 is also referred to as L1).

[0030] The PHY 205 and PHY 215 provide transport channels 244 to the MAC 204 and MAC 214 sublayers. The MAC 204 and MAC 214 sublayers provide logical channels 243 to the RLC 203 and RLC 213 sublayers. The RLC 203 and RLC 213 sublayers provide RLC channels 242 to the PDCP 202 and PCP 212 sublayers. The PDCP 202 and PDCP 212 sublayers provide radio bearers 241 to the SDAP 201 and SDAP 211 sublayers. The radio bearers can be classified into two groups: Data Radio Bearers (DRBs) for user plane data and Signaling Radio Bearers (SRBs) for control plane data. The SDAP 201 and SDAP 211 sublayers provide QoS flows 240 to the 5GC.

[0031] The main services and functions of the MAC204 or MAC214 sublayer are mapping between logical channels and transport channels, multiplexing / demultiplexing of MAC Service Data Units (SDUs) belonging to one or different logical channels into / from Transport Blocks (TBs) delivered on the transport channels to / from the physical layer, scheduling information reporting, error correction with Hybrid Automatic Repeat Request (HARQ) (one HARQ entity per cell in case of Carrier Aggregation (CA)), dynamic scheduling, and the like. The MAC entity supports multiple numerologies, cell(s), and transmission timing(s) for a single UE. ...

[0032] The HARQ function may ensure delivery between peer entities at Layer 1. A single HARQ process may support one TB if the physical layer is not configured for downlink / uplink spatial multiplexing, and a single HARQ process may support one or multiple TBs if the physical layer is configured for downlink / uplink spatial multiplexing.

[0033] The RLC203 or RLC213 sublayer can support three transmission modes: Transparent Mode (TM), Unacknowledged Mode (UM), and Acknowledged Mode (AM). The RLC configuration may be per logical channel independent of numerology and / or transmission duration, and Automatic Repeat Request (ARQ) may operate for any numerology and / or transmission duration for which the logical channel is configured.

[0034] The main services and functions of the RLC203 or RLC213 sub-layer depend on the transmission mode (e.g., TM, UM, or AM) and may include transport of higher layer PDUs, sequence numbering independent of the sequence numbering in PDCP (UM and AM), error correction via ARQ (AM only), segmentation (AM and UM) and re-segmentation (AM only) of RLC SDUs, reassembly of SDUs (AM and UM), duplicate detection (AM only), RLC SDU discard (AM and UM), RLC re-establishment, and protocol error detection (AM only).

[0035] An automatic repeat request in the RLC 203 or RLC 213 sub-layer may have the following characteristics: ARQ retransmits RLC SDUs or RLC SDU segments based on an RLC status report. Polling of RLC status reports may be used when required by RLC. The RLC receiver may also trigger an RLC status report after detecting a missing RLC SDU or RLC SDU segment.

[0036] The main services and functions of the PDCP202 or PDCP212 sub-layer may include forwarding of data (user plane or control plane), maintenance of the PDCP sequence number (SN), header compression and decompression using the Robust Header Compression (ROHC) protocol, header compression and decompression using the EHC protocol, encryption and decryption, integrity protection and integrity verification, timer-based SDU discard, routing for split bearers, duplication, reordering and in-order delivery, out-of-order delivery, and duplication discarding.

[0037] The main services and functions of the SDAP 201 or SDAP 211 include mapping between QoS flows and data radio bearers, and marking of QoS Flow ID (QFI) in both downlink and uplink packets. A single protocol entity of the SDAP may be configured for each individual PDU session.

[0038] As shown in Figure 2B, the control plane protocol stack of the Uu interface (between the UE 125 and the gNB 115) includes a PHY layer (Layer 1), the MAC, RLC, and PDCP sublayers of Layer 2 as described above, and further the RRC 206 and RRC 216 sublayers. The main services and functions of the RRC 206 and RRC 216 sublayers on the Uu interface are the transmission and reception of AS and NAS related system information. Broadcast, paging initiated by 5GC or NG-RAN, establishment, maintenance, and release of RRC connection between UE and NG-RAN (including adding, modifying, and releasing carrier aggregation, and adding, modifying, and releasing dual connectivity within NR or between E-UTRA and NR), security functions including key management, establishment, configuration, maintenance, and release of SRB and DRB, mobility functions (including handover and context transfer, UE cell selection and reselection, and control of cell selection and reselection, and inter-RAT mobility), QoS management functions, UE measurement reporting and control of reporting, detection of radio link failure and recovery from radio link failure, and NAS message transfer from NAS to UE / from UE to NAS. The NAS207 and NAS227 layers are control protocols (terminated in the AMF on the network side) that perform functions such as authentication, mobility management, and security control.

[0039] Sidelink specific services and functions of the RRC sublayer over the Uu interface include configuration of sidelink resource allocation via system information or dedicated signaling, reporting of UE sidelink information, sidelink related measurement configuration and reporting, and reporting of UE assistance information for SL traffic pattern(s).

[0040] 3A, 3B, and 3C show example mappings between logical channels and transport channels in the downlink, uplink, and sidelink, respectively, according to some aspects of one or more example embodiments of the present disclosure. Different types of data transfer services may be provided by the MAC. Each logical channel type may be defined by what type of information is transferred. The logical channels may be classified into two groups: control channels and traffic channels. The control channels may be used for transfer of control plane information only. The Broadcast Control Channel (BCCH) is a downlink channel for broadcasting system control information. The Paging Control Channel (PCCH) is a downlink channel that carries paging messages. The Common Control Channel (CCCH) is a channel for transmitting control information between the UE and the network. This channel may be used for UEs that do not have an RRC connection with the network. The Dedicated Control Channel (DCCH) is a point-to-point bidirectional channel that transmits dedicated control information between the UE and the network and may be used by UEs that have an RRC connection. The traffic channels may be used for transfer of user plane information only. A Dedicated Traffic Channel (DTCH) is a point-to-point channel dedicated to one UE for the transfer of user information. A DTCH can exist in both uplink and downlink. A Sidelink Control Channel (SCCH) is a sidelink channel for transmitting control information (e.g., PC5-RRC and PC5-S messages) from one UE to other UE(s). A Sidelink Traffic Channel (STCH) is a sidelink channel for transmitting user information from one UE to other UE(s). A Sidelink Broadcast Control Channel (SBCCH) is a sidelink channel for broadcasting sidelink system information from one UE to other UE(s).

[0041] Downlink transport channel types include Broadcast Channel (BCH), Downlink Shared Channel (DL-SCH), and Paging Channel (PCH). The BCH may be characterized by a fixed predefined transport format and the requirement to be broadcast in the entire coverage area of ​​a cell, either as a single message or by beamforming different BCH instances. The DL-SCH may be characterized by support for HARQ, support for dynamic link adaptation by varying modulation, coding, and transmit power, the possibility of being broadcast in the entire cell, the possibility of using beamforming, support for both dynamic and semi-static resource allocation, and support for UE discontinuous reception (DRX) to enable UE power savings. The DL-SCH may be characterized by support for HARQ, support for dynamic link adaptation by varying modulation, coding, and transmit power, the possibility of being broadcast in the entire cell, the possibility of using beamforming, support for both dynamic and semi-static resource allocation, and support for UE discontinuous reception (DRX) to enable UE power savings. The PCH may be characterized by support for dynamic link adaptation by varying modulation, coding, and transmit power, the possibility of being broadcast in the entire cell, the possibility of using beamforming, support for both dynamic and semi-static resource allocation, and support for UE discontinuous reception (DRX) to enable UE power saving. The PCH may be characterized by support for UE discontinuous reception (DRX) to enable UE power saving (DRX cycle is indicated to the UE by the network), the requirement to be broadcast in the entire coverage area of ​​the cell, either as a single message or by beamforming different BCH instances, and being mapped to physical resources that may also be dynamically used for traffic / other control channels.

[0042] In the downlink, the following connections may exist between logical channels and transport channels: BCCH may be mapped to BCH, BCCH may be mapped to DL-SCH, PCCH may be mapped to PCH, CCCH may be mapped to DL-SCH, DCCH may be mapped to DL-SCH, and DTCH may be mapped to DL-SCH.

[0043] Uplink transport channel types include the Uplink Shared Channel (UL-SCH) and the Random Access Channel(s) (RACH). The UL-SCH may be characterized by the possibility of using beamforming, support for dynamic link adaptation by varying the transmit power and potentially modulation and coding, support for HARQ, and support for both dynamic and semi-static resource allocation. The RACH may be characterized by limited control information and collision risk.

[0044] In the uplink, the following connections may exist between logical channels and transport channels: CCCH may be mapped to UL-SCH, DCCH may be mapped to UL-SCH, and DTCH may be mapped to UL-SCH.

[0045] Sidelink transport channel types include a Sidelink Broadcast Channel (SL-BCH) and a Sidelink Shared Channel (SL-SCH). The SL-BCH may be characterized by a predefined transport format. The SL-SCH may be characterized by support for unicast, groupcast, and broadcast transmissions, support for both UE autonomous resource selection and scheduled resource allocation by the NG-RAN, support for both dynamic and semi-static resource allocation when the UE is allocated resources by the NG-RAN, support for HARQ, and support for dynamic link adaptation by varying transmit power, modulation, and coding.

[0046] In the sidelink, the following connections may exist between logical channels and transport channels: SCCH may be mapped to SL-SCH, STCH may be mapped to SL-SCH, and SBCCH may be mapped to SL-BCH.

[0047] 4A, 4B, and 4C show example mappings between transport channels and physical channels in the downlink, uplink, and sidelink, respectively, according to some aspects of one or more example embodiments of the present disclosure. The physical channels in the downlink include a physical downlink shared channel (PDSCH), a physical downlink control channel (PDCCH), and a physical broadcast channel (PBCH). The PCH and DL-SCH transport channels are mapped to the PDSCH. The BCH transport channel is mapped to the PBCH. No transport channel is mapped to the PDCCH, and downlink control information (DCI) is carried thereon.

[0048] The physical channels in the uplink include the Physical Uplink Shared Channel (PUSCH), the Physical Uplink Control Channel (PUCCH), and the Physical Random Access Channel (PRACH). The UL-SCH transport channel may be mapped to the PUSCH, and the RACH transport channel may be mapped to the PRACH. The PUCCH is not mapped to any transport channel, and carries uplink control information (UCI).

[0049] The physical channels in the sidelink include the physical sidelink shared channel (PSSCH), the physical sidelink control channel (PSCCH), the physical sidelink feedback channel (PSFCH), and the physical sidelink broadcast channel (PSBCH). The physical sidelink control channel (PSCCH) may indicate the resources and other transmission parameters used by the UE for the PSSCH. The physical sidelink shared channel (PSSCH) may transmit TBs of the data itself, as well as control information for the HARQ procedure and channel state information (CSI) feedback triggering, etc. At least six orthogonal frequency division multiplexing (OFDM) symbols in a slot may be used for the PSSCH transmission. The physical sidelink feedback channel (PSFCH) may carry HARQ feedback over the sidelink from the UE that is the intended recipient of the PSSCH transmission to the UE that performed the transmission. The PSFCH sequence may be transmitted in one PRB that is repeated across two OFDM symbols near the end of the sidelink resources in the slot. The SL-SCH transport channel may be mapped to the PSSCH. The SL-BCH may be mapped to the PSBCH. No transport channel is mapped to the PSFCH, but sidelink feedback control information (SFCI) may be mapped to the PSFCH. No transport channel is mapped to the PSCCH, but sidelink control information (SCI) may be mapped to the PSCCH.

[0050] 5A, 5B, 5C, and 5D illustrate examples of radio protocol stacks for NR sidelink communication according to some aspects of one or more exemplary embodiments of the present disclosure. The AS protocol stack for the user plane (i.e., for STCH) in the PC5 interface may consist of SDAP, PDCP, RLC, and MAC sublayers, and a physical layer. The user plane protocol stack is shown in FIG. 5A. The AS protocol stack for SBCCH in the PC5 interface may consist of RRC, RLC, MAC sublayers, and a physical layer, as shown in FIG. 5B below. For support of the PC5-S protocol, PC5-S sits on top of the PDCP, RLC, and MAC sublayers, and the physical layer in the control plane protocol stack for SCCH for PC5-S, as shown in FIG. 5C. The AS protocol stack for the control plane for SCCH for RRC in the PC5 interface consists of RRC, PDCP, RLC, and MAC sublayers, and a physical layer. The control plane protocol stack for SCCH for RRC is shown in FIG. 5D.

[0051] Sidelink Radio Bearers (SLRBs) may be classified into two groups: Sidelink Data Radio Bearers (SL DRBs) for user plane data and Sidelink Signaling Radio Bearers (SL SRBs) for control plane data. Separate SL SRBs using different SCCHs may be configured for PC5-RRC and PC5-S signaling, respectively.

[0052] The MAC sublayer may provide the following services and functions over the PC5 interface: radio resource selection, packet filtering, priority handling between uplink and sidelink transmissions for a given UE, and sidelink CSI reporting. Due to the limitation of logical channel prioritization in the MAC, sidelink logical channels belonging to the same destination may not be prioritized. Only the source and destination Layer 2 IDs can be multiplexed into the MAC PDU for all unicast, groupcast, and broadcast transmissions that may be associated with a destination. For packet filtering, the SL-SCH contains both the source and destination Layer 2 IDs. A MAC header may be added to the MAC PDU. A Logical Channel Identifier (LCID) contained within the MAC sub-header may uniquely identify a logical channel within the combination of a source Layer 2 ID and a destination Layer 2 ID.

[0053] The services and functions of the RLC sublayer may be supported for the sidelink. Both RLC unacknowledged mode (UM) and acknowledged mode (AM) may be used for unicast transmission, while only UM may be used for groupcast or broadcast transmission. In the case of UM, only one-way transmission may be supported for groupcast and broadcast.

[0054] The PDCP sub-layer services and functions for the Uu interface may be supported for the sidelink with some restrictions, namely, out-of-order delivery may only be supported for unicast transmission and duplication may not be supported over the PC5 interface.

[0055] The SDAP sublayer may provide the following services and functions over the PC5 interface: mapping between QoS flows and sidelink data radio bearers: There may be one SDAP entity per destination for one of unicast, groupcast and broadcast associated with the destination.

[0056] The RRC sublayer may provide the following services and functions over the PC5 interface: transfer of PC5-RRC messages between peer UEs, maintenance and release of PC5-RRC connections between two UEs, detection of sidelink radio link failure of PC5-RRC connections based on indications from MAC or RLC. A PC5-RRC connection may be a logical connection between two UEs for a pair of source layer 2 ID and destination layer 2 ID that may be considered to be established after a corresponding PC5 unicast link is established. There may be a one-to-one correspondence between PC5-RRC connections and PC5 unicast links. A UE may have multiple PC5-RRC connections with one or multiple UEs for different pairs of source layer 2 ID and destination layer 2 ID. Separate PC5-RRC procedures and messages may be used for the UE to transfer UE capabilities and sidelink configurations, including SL-DRB configurations, to a peer UE. Both peer UEs may exchange their own UE capabilities and sidelink configurations using separate bidirectional procedures in both sidelink directions.

[0057] FIG. 6 illustrates example physical signals in the downlink, uplink, and sidelink according to some aspects of one or more example embodiments of the present disclosure. Demodulation reference signals (DM-RS) may be used in the downlink, uplink, and sidelink and may be used for channel estimation. DM-RS is a UE-specific reference signal that may be transmitted along with a physical channel in the downlink, uplink, or sidelink and may be used for channel estimation and coherent detection of the physical channel. Phase tracking reference signals (PT-RS) may be used in the downlink, uplink, and sidelink and may be used to track phase and mitigate performance loss due to phase noise. PT-RS may be primarily used to estimate and minimize the impact of common phase error (CPE) on system performance. Due to phase noise characteristics, PT-RS signals may have low density in the frequency domain and high density in the time domain. PT-RS may occur when the network configures PT-RS to exist in combination with DM-RS. Positioning Reference Signals (PRS) can be used in the downlink for positioning using different positioning technologies. The PRS is used to correlate the received signal from the base station with a local replica in the receiver. The CSI-RS may be used to measure the delay of downlink transmission by correlating the CSI-RS with the UE's UE-specific CSI-RS. The CSI-RS may be used in the downlink and sidelink. The CSI-RS may be used for channel state estimation, reference signal received power (RSRP) measurement for mobility and beam management, time / frequency tracking for demodulation, among others. The CSI-RS may be configured UE-specific, but multiple users may share the same CSI-RS resource. The UE may determine the CSI reports and transfer them to the base station in the uplink using PUCCH or PUSCH. The CSI reports may be carried in the sidelink MAC control element (CE). The primary synchronization signal (PSS) and secondary synchronization signal (SSS) may be used for radio frame synchronization. The PSS and SSS may be used for cell search procedure during initial attach or for mobility purposes. The sounding reference signal (SRS) may be used in the uplink for uplink channel estimation. Similar to the CSI-RS, the SRS may serve as a QCL reference for other physical channels such that they may be configured and transmitted quasi-collocated with the SRS. Sidelink PSS (S-PSS) and Sidelink SSS (S-SSS) may be used in the sidelink for sidelink synchronization.

[0058] 7 illustrates an example of radio resource control (RRC) states and transitions between different RRC states according to some aspects of one or more example embodiments of the present disclosure. A UE may be in one of three RRC states: an RRC connected state 710, an RRC idle state 720, and an RRC inactive state 730. After powering on, the UE may be in the RRC idle state 720, and the UE may use initial access to establish a connection with the network via an RRC connection establishment procedure, perform data transfer, and / or make / receive voice calls. Once an RRC connection is established, the UE may be in the RRC connected state 710. The UE may transition from the RRC idle state 720 to the RRC connected state 710 or from the RRC connected state 710 to the RRC idle state 720 using an RRC connection establishment / release procedure 740.

[0059] The RRC inactive state 730 may be used to reduce signaling load and latency resulting from frequent transitions from the RRC connected state 710 to the RRC idle state 720 when the UE transmits frequent small data. In the RRC inactive state 730, the AS context may be stored by both the UE and the gNB. This may result in a faster state transition from the RRC inactive state 730 to the RRC connected state 710. The UE may transition from the RRC inactive state 730 to the RRC connected state 710 or from the RRC connected state 710 to the RRC inactive state 730 using an RRC connection resume / deactivation procedure 760. The UE may transition from the RRC inactive state 730 to the RRC idle state 720 using an RRC connection release procedure 750.

[0060] FIG. 8 illustrates an example frame structure and physical resources according to some aspects of one or more example embodiments of the present disclosure. Downlink or uplink or sidelink transmissions may be organized into frames of 10 ms duration consisting of 10 (0-9) 1 ms subframes. Each subframe may consist of k slots (k=1, 2, 4, ...), where the number of slots per subframe k may depend on the subcarrier spacing of the carrier on which the transmission takes place. The slot duration may be 14 (0-13) symbols with normal cyclic prefix (CP) and 12 symbols with extended CP, and may scale in time as a function of the subcarrier spacing used such that there is an integer number of slots in a subframe. FIG. 8 illustrates a resource grid in the time and frequency domain. Each element of the resource grid, which includes one symbol in time and one subcarrier in frequency, is referred to as a resource element (RE). A resource block (RB) may be defined as 12 consecutive subcarriers in the frequency domain.

[0061] In some examples, with non-slot-based scheduling, transmission of a packet may occur over a portion of a slot, e.g., 2, 4, or 7 OFDM symbols, which may be referred to as a minislot. Minislots may be used for low latency application examples such as URLLC and operation in unlicensed bands. In some embodiments, minislots may also be used for fast flexible scheduling of services (e.g., preemption of URLLC over eMBB).

[0062] FIG. 9 illustrates example component carrier configurations in different carrier aggregation scenarios according to some aspects of one or more example embodiments of the present disclosure. In carrier aggregation (CA), two or more component carriers (CCs) may be aggregated. A UE may receive or transmit simultaneously on one or more CCs depending on its capabilities. CA may be supported for both contiguous and non-contiguous CCs in the same band or on different bands, as shown in FIG. 9. The gNB and the UE may communicate using a serving cell. The serving cell may be associated with at least one downlink CC (e.g., may be associated with only one downlink CC or may be associated with a downlink CC and an uplink CC). The serving cell may be a primary cell (PCell) or a secondary cCell (SCell).

[0063] The UE can adjust the timing of its uplink transmission using an uplink timing control procedure. A timing advance (TA) can be used to adjust the uplink frame timing relative to the downlink frame timing. The gNB can determine a desired timing advance setting and provide it to the UE. The UE can use the provided TA to determine its uplink transmission timing relative to the UE's observed downlink receive timing.

[0064] In the RRC connected state, the gNB may be responsible for maintaining the timing advance to keep L1 synchronized. Serving cells with uplinks to which the same timing advance is applied and using the same timing reference cell are grouped into a Timing Advance Group (TAG). A TAG may contain at least one serving cell with a configured uplink. The mapping of serving cells to TAGs may be configured by RRC. For a primary TAG, the UE may use the PCell as the timing reference cell, except for shared spectrum channel access where in some cases the SCell may also be used as the timing reference cell. For a secondary TAG, the UE may use any of the activated SCells of this TAG as the timing reference cell and may not change it unless necessary.

[0065] A timing advance update may be signaled by the gNB to the UE via a MAC CE command, which may restart a TAG-specific timer that may indicate whether L1 may be synchronized or not; when the timer is running, L1 may be considered synchronized, otherwise L1 may be considered unsynchronized (uplink transmissions may only be made on the PRACH).

[0066] A UE with single timing advance capability for CA can simultaneously receive and / or transmit on multiple CCs corresponding to multiple serving cells (multiple serving cells grouped into one TAG) sharing the same timing advance. A UE with multiple timing advance capability for CA can simultaneously receive and / or transmit on multiple CCs corresponding to multiple serving cells (multiple serving cells grouped into multiple TAGs) with different timing advances. The NG-RAN may ensure that each TAG includes at least one serving cell. Non-CA A capable UE may receive on a single CC and may transmit on a single CC corresponding to only one serving cell (one serving cell in one TAG).

[0067] The multi-carrier nature of the physical layer in case of CA may be exposed to the MAC layer and one HARQ entity may be required per serving cell. If CA is configured, the UE may have one RRC connection with the network. Upon RRC connection establishment / re-establishment / handover, one serving cell (e.g., PCell) may provide NAS mobility information. Depending on the UE capabilities, the SCell may be configured to form a set of serving cells together with the PCell. The configured set of serving cells for a UE may consist of one PCell and one or more SCells. Reconfiguration, addition, and removal of SCells may be done by RRC.

[0068] In a dual connectivity scenario, a UE may be configured with multiple cells including a Master Cell Group (MCG) for communication with a master base station, a Secondary Cell Group (SCG) for communication with a secondary base station, and two MAC entities, i.e., one MAC entity for the MCG for communication with the master base station and one MAC entity for the SCG for communication with the secondary base station.

[0069] FIG. 10 illustrates an example bandwidth portion configuration and switching according to some aspects of one or more example embodiments of the present disclosure. A UE may be configured with one or more bandwidth portions (BWPs) 1010 (e.g., 1010A, 1010B) on a given component carrier. In some examples, one of the one or more bandwidth portions may be active at a time. The active bandwidth portion may define the UE's operating bandwidth within the operating bandwidth of the cell. For initial access and until the UE's configuration in the cell is received, an initial bandwidth portion 1020 determined from system information may be used. With bandwidth adaptation (BA), for example, through BWP switching 1040, the UE's reception and transmission bandwidth may not be as large as the cell's bandwidth and may be adjusted. For example, the width may be commanded to vary (e.g., to shrink during periods of low activity to save power), the location may move in the frequency domain (e.g., to increase scheduling flexibility), and the subcarrier spacing may be commanded to vary (e.g., to enable different services). The first active BWP 1030 may be the active BWP upon RRC (re)configuration for the PCell or activation of the SCell.

[0070] For a downlink BWP or an uplink BWP in a set of downlink BWP or uplink BWP, respectively, the UE may be provided with the following configuration parameters: subcarrier spacing (SCS), cyclic prefix, common RB and adjacent RBs, index in the set of downlink BWP or uplink BWP by each BWP-Id, a set of BWP common parameters and a set of BWP-specific parameters. The BWP may be associated with an OFDM numerology according to the configured subcarrier spacing and cyclic prefix for the BWP. For the serving cell, the UE may be provided with a default downlink BWP among the configured downlink BWPs. If the UE is not provided with a default downlink BWP, the default downlink BWP may be the initial downlink BWP.

[0071] A downlink BWP may be associated with a BWP inactivity timer. If a BWP inactivity timer associated with an active downlink BWP expires and a default downlink BWP is configured, the UE may perform a BWP switch to the default BWP. If a BWP inactivity timer associated with an active downlink BWP expires and a default downlink BWP is configured, the UE may perform a BWP switch to the default BWP. If not, the UE may perform a BWP switch to the initial downlink BWP.

[0072] FIG. 11 illustrates an example 4-step contention-based random access (CBRA) process and contention-free random access (CFRA) process according to some aspects of one or more example embodiments of the present disclosure. FIG. 12 illustrates an example 2-step contention-based random access (CBRA) process and contention-free random access (CFRA) process according to some aspects of one or more example embodiments of the present disclosure. The random access procedure can be triggered by multiple events, such as initial access from an RRC idle state, an RRC connection re-establishment procedure, downlink or uplink data arrival during an RRC connected state when the uplink synchronization status is "unsynchronized", uplink data arrival during an RRC connected state when there are no PUCCH resources for a Scheduling Request (SR) available, an SR failure, a request by RRC upon synchronization reconfiguration (e.g., handover), a transition from an RRC inactive state to establish time alignment for a secondary TAG, a request for other system information (SI), beam failure recovery (BFR), and consistent uplink listen-before-talk (LBT) failure on the PCell.

[0073] Two types of random access (RA) procedures can be supported: a four-step RA type using MSG1 and a two-step RA type using MSGA. Both types of RA procedures can support contention-based random access (CBRA) and contention-free random access (CFRA), as shown in Figures 11 and 12.

[0074] The UE may select the type of random access at the start of the random access procedure based on the network configuration. If CFRA resources are not configured, the RSRP threshold may be used by the UE to select between the 2-step RA type and the 4-step RA type. If CFRA resources for the 4-step RA type are configured, the UE may perform random access with the 4-step RA type. If CFRA resources for the 2-step RA type are configured, the UE may perform random access with the 2-step RA type.

[0075] MSG1 for the four-step RA type may consist of a preamble on the PRACH (step 1 of CBRA in FIG. 11). After MSG1 transmission, the UE may monitor for a response from the network within a configured window (step 2 of CBRA in FIG. 11). In the case of CFRA, a dedicated preamble for MSG1 transmission may be assigned by the network (step 0 of CFRA in FIG. 11) and upon receiving a random access response (RAR) from the network, the UE may terminate the random access procedure as shown in FIG. 11 (steps 1 and 2 of CFRA in FIG. 11). In the case of CBRA, upon receiving a random access response (step 2 of CBRA in FIG. 11), the UE may transmit MSG3 using the uplink grant scheduled in the random access response (step 3 of CBRA in FIG. 11) and monitor for contention resolution as shown in FIG. 11 (step 4 of CBRA in FIG. 11). If contention resolution is not successful after MSG3 (re)transmission(s), the UE may return to MSG1 transmission.

[0076] The two-step RA type MSGA may include a preamble on PRACH and a payload on PUSCH (e.g., step A of CBRA in FIG. 12). After MSGA transmission, the UE may monitor for a response from the network within a configured window. For CFRA, a dedicated preamble and PUSCH resources may be configured for MSGA transmission (steps 0 and A of CFRA in FIG. 12), and upon receiving a network response (step B of CFRA in FIG. 12), the UE may monitor for a response from the network within a configured window as shown in FIG. 12. In the case of CBRA, if the contention resolution is successful when receiving a network response (step B of CBRA in FIG. 12), the UE may terminate the random access procedure as shown in FIG. 12, whereas if a fallback indication is received in MSGB, the UE may perform MSG3 transmission using the uplink grant scheduled in the fallback indication and monitor contention resolution. If contention resolution is not successful after MSG3 (re)transmission(s), the UE may return to MSGA transmission.

[0077] FIG. 13 illustrates an exemplary time and frequency structure of a synchronization signal and a physical broadcast channel (PBCH) block (SSB) according to some aspects of one or more exemplary embodiments of the present disclosure. The SS / PBCH block (SSB) may consist of a primary synchronization signal and a secondary synchronization signal (PSS, SSS), each occupying one symbol and 127 subcarriers (e.g., subcarrier numbers 56-182 in FIG. 13), and a PBCH on one symbol that spans three OFDM symbols and 240 subcarriers but leaves an unused portion in the middle for the SSS as shown in FIG. 13. The possible time positions of the SSBs within a half-frame may be determined by the subcarrier spacing, and the periodicity of the half-frames during which the SSBs are transmitted may be configured by the network. During a half-frame, different SSBs may be transmitted in different spatial directions (i.e., using different beams that span the coverage area of ​​the cell).

[0078] The PBCH may be used to carry a Master Information Block (MIB) used by the UE during cell search and initial access procedures. The UE may first decode the PBCH / MIB to receive other system information. The MIB may provide the UE with the parameters required to acquire System Information Block 1 (SIB1), more specifically, the information required to monitor the PDCCH for scheduling the PDSCH carrying SIB1. The MIB may also indicate cell barring status information. The MIB and SIB1 may be collectively referred to as Minimum System Information (SI), and SIB1 may be referred to as Remaining Minimum System Information (RMSI). The other System Information Blocks (SIBs) (e.g., SIB2, SIB3, ..., SIB10, and SIBpos) may be referred to as other SIs. Other SI may be broadcast periodically on the DL-SCH, broadcast on demand on the DL-SCH (e.g., upon request from a UE in RRC idle, RRC inactive, or RRC connected state), or sent in a dedicated manner to UEs in RRC connected state on the DL-SCH (e.g., if configured by the network, upon request from a UE in RRC connected state, or when the UE has an active BWP that does not have a configured common search space).

[0079] FIG. 14 illustrates an example SSB burst transmission according to some aspects of one or more example embodiments of the present disclosure. The SSB burst may include N SSBs (e.g., SSB_1, SSB_2, ..., SSB_N), where each SSB of the N SSBs may correspond to a beam (e.g., beam_1, beam_2, ..., beam_N). The SSB burst may be transmitted according to a periodicity (e.g., SSB burst period). During a contention-based random access process, the UE may perform a random access resource selection process, where the UE first selects an SSB before selecting an RA preamble. The UE may select an SSB with an RSRP above a configured threshold. In some embodiments, the UE may select any SSB if an SSB with an RSRP above a configured threshold is not available. A set of random access preambles may be associated with the SSB. After selecting the SSB, the UE may select a random access preamble from the set of random access preambles associated with the SSB, and may transmit the selected random access preamble to initiate the random access process.

[0080] In some embodiments, one beam of the N beams may be associated with a CSI-RS resource (e.g., CSI-RS_1, CSI-RS_2, ..., CSI-RS_N). The UE may measure the CSI-RS resources and may select a CSI-RS having an RSRP above a configured threshold. The UE may select a random access preamble corresponding to the selected CSI-RS and may transmit the selected random access process to initiate the random access process. If there is no random access preamble associated with the selected CSI-RS, the UE may select a random access preamble corresponding to an SSB quasi-co-located with the selected CSI-RS.

[0081] In some embodiments, based on the UE measurements of CSI-RS resources and the UE CSI report, the base station may determine a transmission configuration indication (TCI) state and may indicate the TCI state to the UE, and the UE may use the indicated TCI state for reception of downlink control information (e.g., via PDCCH) or data (e.g., via PDSCH). The UE may use the indicated TCI state to use an appropriate beam for reception of data or control information. The indication of the TCI state may use RRC configuration or may be a combination of RRC signaling and dynamic signaling (e.g., via MAC Control Element (MAC CE) and / or based on values ​​of fields in the downlink control information that schedules downlink transmissions). The TCI state may indicate a quasi-co-location (QCL) relationship between a downlink reference signal, such as a CSI-RS, and a DM-RS associated with a downlink control or data channel (e.g., PDCCH or PDSCH, respectively).

[0082] In some embodiments, the UE may be configured with a list of up to M TCI state configurations using physical downlink shared channel (PDSCH) configuration parameters to decode PDSCH according to a detected PDCCH with DCI intended for the UE and a given serving cell, where M may depend on the UE capabilities. Each TCI-State may include parameters to configure a QCL relationship between one or two downlink reference signals and a DM-RS port of PDSCH, a DM-RS port of PDCCH, or a CSI-RS port(s) of CSI-RS resources. The quasi-collocation relationship may be configured by one or more RRC parameters. The quasi-collocation type corresponding to each DL RS may take one of the following values: "QCL-TypeA": {Doppler shift, Doppler spread, average delay, delay spread}, "QCL-TypeB": {Doppler shift, Doppler spread}, "QCL-TypeC": {Doppler shift, average delay}, "QCL-TypeD": {Spatial Rx parameters}. The UE may receive an activation command (eg, MAC CE) used to map the TCI state to a codepoint of the DCI field.

[0083] FIG. 15 illustrates example components of a user terminal and a base station for transmission and / or reception in accordance with some aspects of one or more example embodiments of the present disclosure. In one embodiment, the example components of FIG. 15 may be considered to be illustrative of functional blocks of an example base station 1505. In another embodiment, the example components of FIG. 15 may be considered to be illustrative of functional blocks of an example user equipment (UE) 1500. Thus, the components illustrated in FIG. 15 are not necessarily limited to either a UE or a base station.

[0084] 15, an antenna 1510 may be used for transmission or reception of electromagnetic signals. The antenna 1510 may include one or more antenna elements, and may be used in multiple-input multiple-output (MIMO) configurations, multiple-input single-output (MISO) configurations, and single-input multiple-output (SIMO) configurations. In some embodiments, the antenna 1510 may enable massive MIMO configurations with tens or hundreds of antenna elements. The antenna 1510 may enable other multi-antenna techniques such as beamforming. In some examples, depending on the capabilities of the UE 1500 or the type of the UE 1500 (e.g., a low complexity UE), the UE 1500 may only support a single antenna.

[0085] The transceiver 1520 can communicate wireless links described herein bidirectionally via the antenna 1510. For example, the transceiver 1520 may represent a wireless transceiver in a UE and may communicate bidirectionally with a wireless transceiver in a base station, or vice versa. The transceiver 1520 may include a modem for modulating packets, providing the modulated packets to the antenna 1510 for transmission, and demodulating packets received from the antenna 1510.

[0086] The memory 1530 may include RAM and ROM. The memory 1530 may store computer readable computer executable code 1535 including instructions that, when executed, cause the processor to perform various functions described herein. In some examples, the memory 1530 may include a basic input / output system (BIOS) that may control basic hardware or software operations such as interaction with peripheral components or devices, among other things.

[0087] The processor 1540 may include a hardware device having processing capabilities (e.g., a general purpose processor, a digital signal processor (DSP), a central processing unit (CPU), a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a programmable logic device, discrete gate or transistor logic components, discrete hardware components, or any combination thereof). In some examples, the processor 1540 may be configured to operate a memory using a memory controller. In other examples, a memory controller may be integrated into the processor 1540. The processor 1540 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 1530) to cause the UE 1500 or the base station 1505 to perform various functions.

[0088] The CPU 1550 may perform basic arithmetic, logical, control, and input / output (I / O) operations specified by computer instructions in the memory 1530. The UE 1500 and / or base station 1505 may include additional peripheral components such as a graphics processing unit (GPU) 1560 and a global positioning system (GPS) 1570. The GPU 1560 is dedicated circuitry for rapid manipulation and modification of the memory 1530 to accelerate processing performance of the UE 1500 and / or base station 1505. The GPS 1570 may be used, for example, to enable location-based services or other services based on the geographic location of the UE 1500.

[0089] In some examples, a UE 1500 (apparatus) may be configured or programmed for channel state information (CSI) report transmission in a mobile communication network. The UE 1500 may include a memory (e.g., memory 1530 of FIG. 15) that stores instructions (e.g., code 1535 of FIG. 15) and a processor (e.g., processor 1540 of FIG. 15) configured to execute the instructions to receive CSI configuration parameters. The CSI configuration parameters may include a first CSI configuration parameter associated with a multicast broadcast service (MBS) and a second CSI configuration parameter associated with a unicast service. The processor measures one or more first reference signals based on the first CSI configuration parameter, measures one or more second reference signals based on the second CSI configuration parameter, transmits a first CSI report associated with the one or more MBSs based on the measurement of the first reference signal, and transmits a first CSI report associated with the one or more unicast services based on the measurement of the second reference signal. In these examples, a memory (e.g., memory 1530) of the UE 1500 may store computer program code (e.g., code 1535) executable by a processor (e.g., CPU 1550) to perform functions of the UE 1500.

[0090] In some examples, the base station 1505 may be configured or programmed for CSI report transmission in a mobile communication network. The base station 1505 may include a memory (e.g., memory 1530 of FIG. 15) storing instructions (e.g., code 1535 of FIG. 15) and a processor (e.g., processor 1540 of FIG. 15) configured to execute the instructions to transmit CSI configuration parameters to a UE (e.g., UE 1500). The CSI configuration parameters may include a first CSI configuration parameter associated with the MBS and a second CSI configuration parameter associated with the unicast service. The UE may be configured to measure one or more first reference signals based on the first CSI configuration parameter and measure one or more second reference signals based on the second CSI configuration parameter. The processor may be configured to execute the instructions to transmit downlink control information indicating a request for transmission of at least one of the first CSI report or the second CSI report. The downlink control information may trigger the UE to generate and / or transmit at least one of the first CSI report or the second CSI report. In these examples, a memory (e.g., memory 1530) of the base station 1505 may store computer program code (e.g., code 1535) executable by a processor (e.g., CPU 1550) to perform functions of the base station 1505.

[0091] In some examples, the UE 1500 and the base station 1505 are included in a system for mobile communication. The base station may be configured or programmed to transmit CSI configuration parameters to the UE. The CSI configuration parameters may include a first CSI configuration parameter associated with the MBS and a second CSI configuration parameter associated with the unicast service. In this system, the UE may be configured or programmed to measure one or more first reference signals based on the first CSI configuration parameter and measure one or more second reference signals based on the second CSI configuration parameter.

[0092] In some examples, MBS services may be enabled via single-cell transmission. MBS may be transmitted within the coverage of a single cell. One or more multicast / broadcast control channels (e.g., MCCH) and one or more multicast / broadcast data channels (e.g., MTCH) may be mapped onto the DL-SCH. Scheduling may be performed by the gNB. Multicast / broadcast control channel and multicast / broadcast data channel transmissions may be indicated by logical channel specific RNTIs on the PDCCH. In some examples, a one-to-one mapping between a service identifier, such as a Temporary Mobile Group Identifier (TMGI), and a RAN level identifier, such as a Group Identifier (G-RNTI), may be used for reception of the DL-SCH to which the multicast / broadcast data channel may be mapped. In some examples, a single transmission may be used for the DL-SCH associated with the multicast / broadcast control channel and / or multicast / broadcast data channel transmissions, HARQ or RLC retransmissions may not be used, and / or RLC unacknowledged mode (RLC UM) may be used. In other examples, some feedback (eg, HARQ feedback or RLC feedback) may be used for transmission over a multicast / broadcast control channel and / or a multicast / broadcast data channel.

[0093] In some examples, for a multicast / broadcast data channel, the following scheduling information is provided: A scheduling cycle, a multicast / broadcast data channel on duration (e.g., the duration the UE waits to receive a PDCCH after waking up from DRX), and a multicast / broadcast data channel inactivity timer (e.g., the duration the UE waits to successfully decode a PDCCH, failing which it re-enters DRX, since the last successful decoding of a PDCCH indicating the DL-SCH to which this multicast / broadcast data channel is mapped) may be provided on the multicast / broadcast control channel.

[0094] In some examples, the one or more UE identities may relate to the MBS transmission. The one or more identities may include at least one of one or more first RNTIs identifying a transmission of a multicast / broadcast control channel and one or more second RNTIs identifying a transmission of a multicast / broadcast data channel. The one or more first RNTIs identifying a transmission of a multicast / broadcast control channel may include a single-cell RNTI (SC-RNTI, other names may be used). The one or more second RNTIs identifying a transmission of a multicast / broadcast data channel may include a G-RNTI (nG-RNTI, other names may be used).

[0095] In some examples, one or more logical channels may be related to MBS transmission. The one or more logical channels may include a multicast / broadcast control channel. The multicast / broadcast control channel may be a point-to-multipoint downlink channel used to transmit MBS control information from the network to the UE for one or more multicast / broadcast data channels. This channel may be used by UEs that receive or are interested in receiving the MBS. The one or more logical channels may include a multicast / broadcast data channel. This channel may be a point-to-multipoint downlink channel for transmitting MBS traffic data from the network.

[0096] In some examples, a procedure may be used by the UE to inform the RAN that the UE is receiving or is interested in receiving MBS service(s) via an MBS radio bearer, and if so, inform the 5G RAN of the priority of MBS vs. unicast reception or receive-only mode MBS service(s) reception. An example is shown in FIG. 16. The UE may transmit a message (e.g., MBS interest indication message) to inform the RAN that the UE is receiving / interested in receiving or no longer receiving / not interested in receiving MBS service(s). The UE may transmit the message, for example, based on receiving one or more messages (e.g., SIB message or unicast RRC message) from the network indicating one or more MBS service area identifiers of the current and / or adjacent carrier frequencies.

[0097] In some examples, a UE may consider an MBS service to be part of an MBS service of interest if the UE is capable of receiving the MBS service (e.g., via a single cell point-to-multipoint mechanism), and / or if the UE is receiving or is interested in receiving the MBS service via a bearer associated with the MBS service, and / or if one session of the MBS service is in progress or about to start, and / or if at least one of one or more MBS service identifiers indicated by the network is of interest to the UE.

[0098] In some examples, control information for reception of MBS services may be provided on a particular logical channel (e.g., the MCCH). The MCCH may carry information about ongoing MBS sessions as well as when each session may be scheduled, e.g., schedule The UE may carry one or more configuration messages indicating a polling period, a scheduling window, and a starting offset. The one or more configuration messages may provide information about neighboring cells carrying MBS sessions that may be ongoing on the current cell. In some examples, the UE may receive a single MBS service at a time or two or more MBS services in parallel.

[0099] In some examples, MCCH information (e.g., information transmitted in a message transmitted over the MCCH) may be transmitted periodically using a configurable repetition period. The MCCH transmission (and associated radio resources and MCS) may be indicated on the PDCCH.

[0100] In some examples, modification of MCCH information may occur in a particular radio frame / subframe / slot and / or a modification period may be used. For example, within a modification period, the same MCCH information may be transmitted multiple times as defined by its scheduling (based on the repetition period). The modification period boundary may be defined by a SFN value, SFN mod m=0, where m is the number of radio frames that includes the modification period. The modification period may be configured by SIB or by RRC signaling.

[0101] In some examples, when the network changes (a part of) the MCCH information, it may notify the UE about the change in the first subframe / slot that may be used for MCCH transmission during the repetition period. Upon receiving the change notification, the UE that is interested in receiving the MBS service may acquire the new MCCH information starting from the same subframe / slot. The UE may apply the previously acquired MCCH information until it acquires the new MCCH information.

[0102] In one example, the system information block (SIB) may include information required to obtain control information associated with the transmission of the MBS, which may include at least one of one or more discontinuous reception (DRX) parameters for monitoring scheduling information of the control information related transmission of the MBS, a scheduling period and an offset of the scheduling information of the control information related transmission of the MBS, a modification period for modifying the content of the control information related transmission of the MBS, repetition information for repetition of the control information related transmission of the MBS, etc.

[0103] In one example, an information element (IE) may provide configuration parameters indicating, for example, a list of ongoing MBS sessions transmitted over one or more bearers for each MBS session, one or more associated RNTIs (e.g., G-RNTI, other names may be used), and scheduling information. The configuration parameters may include at least one of one or more timer values ​​(e.g., inactivity timer or on-duration timer) for discontinuous reception (DRX), an RNTI for scrambling scheduling and transmission of a multicast / broadcast traffic channel (e.g., MTCH, other names may be used), the ongoing MBS sessions, one or more power control parameters, one or more scheduling periodicity and / or offset values ​​for one or more MBS traffic channels, information about a list of neighbor cells, etc.

[0104] Exemplary embodiments may enable RAN functionality for broadcast / multicast for UEs in RRC_CONNECTED, RRC_IDLE, and RRC_INACTIVE states. A group scheduling mechanism may be used to enable UEs to receive broadcast / multicast services. In some examples, broadcast / multicast services may be enabled to operate simultaneously with unicast reception. In some examples, broadcast / multicast service delivery may be combined with multicast (PTM) and unicast (PTM) with service continuity for a given UE. In some examples, the coordination function may reside in the gNB-CU. In some examples, the reliability of the broadcast / multicast service may be improved by UL feedback. The level of reliability may be based on the requirements of the application / service provided. In some examples, the broadcast / multicast transmission area may be dynamically controlled within one gNB-DU.

[0105] In some examples, Multicast and Broadcast Services (MBS) services may be provided using a Point-to-Multipoint (PTM), e.g., Single Cell Point-to-Multipoint (SC-PTM) framework. The SC-PTM framework may also be used for one or more of Mission Critical Push-to-Talk (MCPTT), Internet of Things (IoT), and Vehicle-to-Everything (V2X) communications. In some examples of the Single Cell Point-to-Multipoint framework, a gNB may use a Physical Downlink Shared Channel (PDSCH) to transmit broadcast data and control information to a group of UEs via one or more cells. In some examples, data of the MBS service may be transmitted on the PDSCH using a first RNTI, e.g., a group-specific Radio Network Temporary Identifier (e.g., G-RNTI), and control information associated with the MBS service may be transmitted on the PDSCH using a second RNTI, e.g., a Single Cell Point-to-Multipoint Radio Network Temporary Identifier (e.g., SC-RNTI).

[0106] In some examples, such as shown in FIG. 17, to receive a single-cell point-to-multipoint transmission, the UE may receive one or more of MBS broadcast control information, e.g., received using a broadcast channel (e.g., System Information Block (SIB)), a multicast control channel (e.g., Single Cell Multicast Control Channel (SC-MCCH)), and a multicast traffic channel (e.g., Single Cell Multicast Traffic Channel (SC-MTCH)). For example, the MBS broadcast control information (e.g., transmitted via the SIB) may indicate how to receive a multicast control channel (e.g., SC-MCCH) carrying MBS-related control information. The multicast control channel may indicate available MBS service identifiers (e.g., Temporary Mobile Group Identities (TMGIs)) and how to receive a multicast traffic channel (e.g., SC-MTCH). The multicast control channel may further indicate a RAN identifier (such as a Group Radio Network Temporary Identifier (G-RNTI)) associated with the MBS service identifier (e.g., TMGI). For example, the multicast control channel may indicate a mapping between the TMGI and the G-RNTI. The information carried by the multicast control channel may remain unchanged within the modification period or may change based on the modification period. The multicast control channel information may be repeated within the modification period based on the repetition period. The MBS broadcast control information may indicate the modification period and / or the repetition period. The multicast traffic channel may be used to transfer data of the MBS service. The multicast control channel (e.g., SC-MCCH) may carry a message (e.g., SCPTM configuration message) including configuration parameters for receiving MBS data via the MBS traffic channel. The configuration parameters may indicate ongoing MBS sessions and information for which each session may be scheduled. The configuration parameters may include a neighbor cell list for potential neighbors that provide the same Temporary Mobile Group Identity (TMGI).

[0107] In some examples, the UE may initially discover and subscribe to an MBS service through application layer signaling or by other means, such as pre-provisioning in the device. Such service discovery signaling / provisioning may include providing some service identifiers for the subscribed MBS services to the UE. E. In some examples, the service identifier may be a Temporary Mobile Group Identity (TMGI).

[0108] In some examples, when a UE in RRC_CONNECTED state receives a PDSCH carrying MBS data, the UE may feedback an ACK for successfully receiving the PDSCH or a NACK for not successfully receiving the PDSCH in the form of uplink control information (UCI). The UE may determine a PUCCH resource set according to the size of the UCI information. In some examples, the UE may determine a PUCCH resource from the resource set by using a PUCCH resource indicator field of the DCI that schedules the PDSCH carrying MBS data. In some examples, the gNB may perform unicast-based retransmission based on the feedback on the PUCCH resources of each UE, or the gNB may perform multicast-based retransmission if the gNB receives at least one NACK feedback.

[0109] In some examples, multiple UEs may share a common NACK resource for HARQ feedback of MBS data. In a NACK-only feedback mode, if the UE does not successfully receive the corresponding MBS PDSCH, the UE may feedback a NACK, otherwise the UE may not provide feedback. In some examples, the gNB may configure a PUCCH resource to carry only NACKs. In some examples, when the gNB receives at least one NACK feedback in a NACK resource, for example, based on energy detection, the gNB may perform a multicast-based retransmission.

[0110] In some examples, both HARQ ACK and HARQ NACK feedback may be used. In some examples, the UE may transmit only NACKs using, for example, shared PUCCH resources.

[0111] In some examples, a UE-specific ACK / NACK mechanism may be used. The UE can send an ACK if the packet is received correctly and a NACK if it is received incorrectly. Each UE has separate resources for transmitting the ACK / NACK.

[0112] In some examples, a group NACK mechanism may be used. A UE may send a NACK if a packet is received incorrectly and may not provide feedback if the packet is received correctly. Multiple UEs may share the same resource for transmitting NACKs.

[0113] In some examples, autonomous / blind retransmission without or with feedback for aggregated PDSCHs may be used: the transmitter may autonomously retransmit data without waiting for feedback or bundled feedback for an aggregated set of PDSCHs for the same TB.

[0114] In some examples, a multicast retransmission based on group NACK may be used: A transmitter may retransmit data if there is a NACK from at least one UE that was unable to successfully decode the data.

[0115] In some examples, retransmissions may be multicast or unicast based on UE-specific ACK / NACK feedback. The transmitter may retransmit data by using the G-RNTI PDSCH or C-RNTI PDSCH, for example, based on the number of UEs that failed to receive the initial transmission.

[0116] In some examples, CSI (e.g., CQI, PMI, RI, RSRP / RSRQ, SINR, SRI, CRI, interference conditions) feedback can improve performance through adaptive link adaptation in changing communication environments or to assist in management / operation of UE groupings.

[0117] In some examples, a UE receiving a PTM transmission may have its own UL resources for transmitting the corresponding HARQ feedback, and in some examples, the PUCCH resources for the PTM HARQ feedback may be dedicated to the PTM HARQ feedback.

[0118] In some examples, PUCCH resources may be shared by PTM HARQ feedback and PTP HARQ feedback.

[0119] In some examples, the UE may use separate HARQ feedback codebooks for PTM and PTP transmissions.

[0120] In some examples, the HARQ feedback codebook may include HARQ feedback for both PTM and PTP transmissions.

[0121] In some examples, CSI feedback (e.g., CQI / PMI / RI) may be used to improve PTM transmission reliability with higher resource efficiency. With CSI feedback, the gNB can know the rough direction of the UE and what is the correct MCS to be used. In some examples, a PTM-specific CSI-RS with a different scrambling ID compared to the PTP CSI-RS may be configured, and the UE can measure and report PTM-specific channel related information. In some examples, the UEs in a PTM group may be configured with one or more CSI-RS for PTM and corresponding CSI reporting configurations.

[0122] In some examples, UE feedback, such as positive or negative acknowledgements (e.g., HARQ positive / negative acknowledgements or higher layer (e.g., RLC and / or PDCP) positive / negative acknowledgements), can improve reliability for receiving multicast and broadcast services (MBS) services.

[0123] In some examples, MBS services may be provided using point-to-multipoint (PTM) transmission in a cell. A physical downlink shared channel (PDSCH) of a cell may be used to transmit multicast / broadcast data and control information by a base station to a group of UEs. For example, data of the MBS service may be transmitted over the PDSCH with a first RNTI (e.g., a group-specific radio network temporary identifier (G-RNTI)), and control information may be transmitted over the PDSCH with a second RNTI (e.g., a single-cell point-to-multipoint (SC-PTM) radio network temporary identifier (SC-RNTI)). In some examples, reliability of the MBS service may be improved by using a HARQ mechanism and by transmitting HARQ and CSI feedback.

[0124] In some examples, a wide range of MBS use cases may be used, including MBS services, mission-critical communications, Internet of Things (IoT), and vehicle-to-everything (V2X), etc. Some MBS use cases may include transmission of periodic or aperiodic traffic with low to high data rates targeted to a few to thousands of UEs in a cell. In some examples, reliability requirements may vary depending on the MBS use case and / or deployment scenario (e.g., HARQ-based retransmissions or CSI feedback). ) UE feedback mechanisms may vary based on MBS use cases and / or deployment scenarios.

[0125] In some examples, the retransmissions may be at the PDCP and / or RLC sublayer. RLC and / or PDCP retransmissions may be sufficient for some use cases, and PHY / MAC-based retransmissions (e.g., HARQ-based retransmissions) may not be required. In some examples, RLC and / or PDCP retransmissions may not meet the required latency and efficiency for some of the MBS use cases. In some examples, it may be necessary to support HARQ for MBS transmission. In some examples, the UE may report CSI feedback to improve the efficiency and reliability of the MBS transmission. In some examples, the UE and the base station may support HARQ for MBS transmission on the PDSCH, and the UE may transmit HARQ feedback (e.g., HARQ ACK / NAK) and CSI feedback to the base station to improve the reliability and efficiency of the MBS service.

[0126] An exemplary retransmission mechanism involving retransmissions in PDCP / RLC or MAC / PHY (e.g., HARQ-based retransmissions) is shown in FIG. 18. In the exemplary retransmission mechanism, the UE can support blind retransmissions of MTCH data using resources scheduled / configured based on the MCCH. The UE may not transmit HARQ feedback and may use a small number of retransmissions that may be configured based on higher layer retransmissions, e.g., PDCP or RLC retransmissions. In the exemplary retransmission mechanism, the UE can support synchronous HARQ retransmissions based on UE feedback. Resources for retransmissions may be pre-determined / pre-configured at the time of the first transmission, and resources for retransmissions may be used based on UE feedback, if necessary. In some examples, synchronous HARQ retransmissions may be used by UEs in an RRC connected state. In some examples, synchronous HARQ retransmissions may be used by UEs in an RRC connected state, inactive state, or idle state, which may improve power efficiency since resources used by possible retransmissions are pre-configured and may be used by the UE without monitoring extra PDCCH for scheduling resources for retransmissions. In an exemplary retransmission mechanism, asynchronous HARQ with incremental redundancy (IR) may be used, where retransmissions may be dynamically scheduled using downlink control information (e.g., as in unicast). This process may be more spectrally efficient. UEs that have not received a previous transmission may monitor the PDCCH until they receive the retransmitted packet. In some examples, the UE may use one or more of the retransmission mechanisms described above.

[0127] In some examples, if the RAN receives a negative acknowledgement (NACK) from only a few and / or known UEs, the RAN may retransmit the data to those UEs via unicast, otherwise the retransmission may be multicast, in which case UEs that have already received the data may ignore such retransmission. In some examples, with synchronous HARQ retransmissions, the UE may identify and avoid retransmitting MBS transport blocks that have already been received.

[0128] In some examples, when a UE is configured with HARQ feedback for MBS data, the configuration of such HARQ feedback across UEs may take into account the coverage and number of UEs, as well as trade-offs between QoS / reliability requirements for MBS services and UE power savings and signaling overhead.

[0129] In some examples, various MBS services may be available for a UE. Some of the MBS services may include long-term transmission of periodic traffic. In some examples, MBS services may be delivered to UEs in all RRC states. In some examples, UEs in RRC idle / inactive state may use their own RRC state to trigger data retransmissions when necessary. UEs in RRC idle and inactive states may receive the MBS data and, if configured, provide feedback to the network.

[0130] In some examples, the UE can provide higher layer, e.g., PDCP / RLC feedback for MBS data delivery when configured by the network. In some examples, the UE can be configured to provide higher layer, e.g., PDCP / RLC feedback for MBS data delivery issues. In some examples, the UE can provide HARQ feedback for MBS data when the UE is in one of various defined RRC states. For example, the UE may be in an RRC idle state or an RRC inactive state and can provide HARQ feedback when configured by the network. In some examples, the UE can provide HARQ feedback for MBS data when configured by the network. Exemplary options (i), (ii), (iii), and (iv) for HARQ feedback in connected, idle, and inactive states are shown in FIG. 19. In some examples, a UE in all RRC states including idle / inactive can be configured to provide HARQ feedback. In some examples, the UE can transition to an RRC connected state to provide HARQ feedback (e.g., option (i) in FIG. 19).

[0131] In some examples, HARQ feedback from RRC idle / inactive UEs may be supported. In one example, UEs in RRC idle or inactive may return to the RRC connection to send their negative feedback regarding MBS data reception. In one example, UEs in RRC idle or inactive may send HARQ feedback without retuning to the RRC connected state (e.g., options (ii), (iii) and (iv) in FIG. 19). In some examples, for MBS HARQ, the RAN may configure UEs in RRC idle or inactive to send HARQ feedback without retuning to the RRC connected state. For example, for UEs in RRC idle and inactive states, the UEs may use PRACH to convey HARQ NACKs to the RAN, and PRACH resources may be reserved to enable contention-free access. In some examples, some common PUCCH resources may be configured to be used by such UEs to send their feedback. In some examples, UEs in RRC idle or inactive states may use contention-free RACH to send HARQ NACKs for a given MBS service. The NACK for one or more MBS services may be transmitted via payload in a selected or designated message based on a particular RACH implementation. For example, according to a two-step RACH implementation, the NACK may be included as payload in message A. In another example, according to a four-step RACH implementation, the NACK may be included as payload in message 3. In some examples, the RAN may configure different preamble codes associated with different MBS services as part of the MBS configuration, and the UE may indicate its NACK for the MBS service by transmitting a PRACH with the corresponding preamble.In some examples, UEs in idle or inactive state may be configured with common PUCCH resources for transmitting NACK feedback, and UEs in connected state may reuse and share their PUCCH for unicast services for transmitting their MBS feedback.

[0132] In some examples, the number of UEs receiving the MBS may be large and the network may need to limit the amount of feedback it receives. In some examples, HARQ feedback transmission from the UE for the MBS may be limited to transmitting NACKs based on network / RRC configuration. For example, the UE may not receive HARQ feedback because the HARQ feedback is NACKs only. The packet may also receive a configuration parameter indicating whether the packet may be transmitted for ACK and NACK only, or for both ACK and NACK.

[0133] In some examples, HARQ feedback transmission from UEs for MBS may be limited to UEs that are within a configured distance from the base station or based on a threshold on received reference signal received power (RSRP) level.

[0134] In some examples, the CSI feedback may be transmitted by the UE to optimize the MCS level and MIMO configuration of the MBS data. In some examples, the CSI feedback may be configured UE-specifically and the network may request CSI feedback from a subset of UEs at a certain time.

[0135] In some examples, the network may indicate CSI-RS resources for the UE to measure for MBS data, and the configured CSI-RS resources may be different from those used for unicast, e.g., MBS data may not be beamformed or may have a wider beam than unicast data transmitted to different UEs in the MBS group. In the absence of such configuration or quasi-colocation (QCL) information, the UE may assume that MSB data is transmitted co-located with SSB.

[0136] In some examples, the RAN may indicate CSI-RS resources / ports for the UE to measure for CSI feedback. Such indication may be sent as a unicast RRC message to the UEs instructed to transmit CSI feedback or may be included in a common MBS configuration available to all UEs.

[0137] In some examples, UEs may transmit their CSI feedback based on the MBS data when they are in an RRC connected state.

[0138] In some examples, given the nature of MBS data transmission, periodic CSI feedback may have limited use and may require some multiplexing and design considerations in the PUCCH configuration. In some examples, MBS CSI feedback may be based on DCI-triggered aperiodic CSI feedback.

[0139] In some examples, the network may instruct the UEs to transmit their CSI feedback using a common set of PUCCH resources or based on message 3 / A of the 4 / 2-step RACH using one of the designated PRACH resources. In some examples, the subset of UEs for transmitting CSI feedback may be selected randomly using a randomization seed and / or based on their received signals from the base station. In some examples, the RAN may decide to change transmission parameters based on the CSI feedback. The CSI feedback may be spread over a time window, so different UEs may transmit their feedback at different times and may use a randomization seed.

[0140] In an example embodiment as shown in FIG. 20, the UE may receive one or more messages (e.g., RRC messages) including configuration parameters. The configuration parameters may include configuration parameters for a reference signal. The configuration parameters for the reference signal may indicate radio resources for the reference signal. In some examples, the UE may receive a dedicated RRC message including configuration parameters for the reference signal. In some examples, the UE may receive a broadcast message (e.g., a SIB message) including configuration parameters for the reference signal. In some examples, the reference signal may include a channel state information reference signal (CSI-RS). In some examples, the reference signal may include a synchronization signal (SSB) reference signal.

[0141] The UE may measure the reference signal (e.g., measure a radio resource indicated by the reference signal) based on a configuration parameter of the reference signal. The reference signal may be used by the UE to determine whether to transmit HARQ feedback or not to transmit HARQ feedback. In one example, the reference signal may be used by the UE to determine whether to transmit HARQ feedback or not to transmit HARQ feedback for a received transport block associated with a service type (e.g., a Multicast and Broadcast Services (MBS) service type). The UE may measure a reference signal and may determine a received power level associated with the reference signal (e.g., a reference signal received power (RSRP) of the reference signal. The UE may determine whether the reference signal received power (RSRP) of the reference signal is above a threshold. The UE may determine that the reference signal received power is above a threshold based on the reference signal measurement. In some demonstrative examples, the threshold may have a predetermined value. In some examples, the UE may receive one or more configuration parameters indicative of the threshold. In one example, the UE may be in an RRC idle state or an RRC inactive state. The UE may receive a broadcast message (e.g., a SIB) including one or more configuration parameters indicative of the threshold. In one example, the UE may be in an RRC connected state. The UE may receive an RRC message including one or more configuration parameters indicative of the threshold.

[0142] The UE may receive a downlink data channel (e.g., a PDSCH) carrying a downlink transport block. The downlink transport block may be an MBS transport block. The UE may receive the downlink MBS transport block via a traffic channel (e.g., a Multicast Traffic Channel (MTCH) logical channel) associated with the MBS service. For example, the UE may receive control information indicating scheduling information for the MBS transport block (e.g., via a control channel such as a Multicast Control Channel (MCCH)) and may receive the downlink MBS transport block using scheduling information indicated by the control information.

[0143] The UE may determine whether the received downlink MBS transport block is successfully received. The UE may determine whether to transmit HARQ feedback associated with the downlink MBS transport block based on comparing the reference signal received power with a threshold. For example, the UE may determine to transition HARQ feedback associated with the received downlink MBS transport block based on the reference signal received power being greater than a threshold. For example, the UE may determine to transition HARQ feedback associated with the received downlink MBS transport block based on the reference signal received power being greater than a threshold and based on the HARQ feedback being a negative acknowledgement. For example, the UE may transmit HARQ feedback only if the reference signal received power is greater than a threshold and the HARQ feedback is a NACK. The UE may transmit HARQ feedback associated with the downlink transport block via an uplink control channel. In some examples, the uplink control channel may be specific to the MBS service. In some examples, the uplink control channel may be shared between MBS data and unicast data. In some examples, based on the transmission of the HARQ feedback, the UE may receive a retransmission of the downlink MBS transport block.

[0144] In an exemplary embodiment as shown in FIG. 21, the UE may be in a specified state, such as an RRC inactive state or an RRC idle state. The UE may receive MBS transport blocks while in the RRC inactive state or the RRC idle state. For example, The UE may receive the downlink MBS transport block using radio resources scheduled by control information associated with the MBS service (e.g., control information carried by a multicast control channel (e.g., MCCH)). The UE may determine whether the downlink MBS transport block is correctly received (e.g., using a decoding process and / or based on error detection using a cyclic redundancy check (CRC) code). The UE may decide to transmit HARQ feedback for the MBS transport block. For example, the UE may decide to transmit HARQ feedback based on the HARQ feedback being a negative acknowledgement. For example, the UE may decide to transmit HARQ feedback based on the HARQ feedback being a negative acknowledgement and based on comparing a received power level of a reference signal to a threshold. Based on the decision to transmit HARQ feedback for the transport block and based on the UE being in an RRC idle state or an RRC inactive state, the UE may transmit the HARQ feedback using a random access process (e.g., a two-step random access process or a four-step random access process) or may transmit an indication of the HARQ feedback. For example, one or more messages of the random access process may be used to carry HARQ feedback or an indication of HARQ feedback.

[0145] In some examples, the UE may transition to an RRC connected state based on a random access process.

[0146] In some examples, the UE may remain in an RRC inactive state or an RRC idle state (e.g., the UE's RRC state prior to the indication of HARQ feedback via the random access process) after or before completion of the random access process and after transmission of the HARQ feedback or an indication of HARQ feedback.

[0147] In some examples, the UE may transition from an RRC inactive state or an RRC idle state (e.g., the UE's RRC state prior to the indication of HARQ feedback via the random access process) to an RRC connected state based on the random access process (e.g., after completion of the random access process). After transitioning to the RRC connected state, the UE may transmit HARQ feedback associated with the MBS transport block via an uplink control channel. For example, the UE may receive configuration parameters for the uplink control channel via message 4 (in a four-step random access process) or message B (in a two-step random access process).

[0148] In some examples, the UE may transmit a random access preamble to initiate a random access process. The random access preamble may indicate HARQ feedback. For example, one or more first random access preambles may be configured / preconfigured as a negative acknowledgement (NACK). For example, one or more first random access preambles may be configured / preconfigured as a negative acknowledgement (NACK), and one or more second random access preambles may be configured / preconfigured as an acknowledgement (ACK). The base station may determine HARQ feedback for the UE based on the random access preamble used in the random access process. For example, the UE may receive a configuration parameter indicating which preambles are used for ACK or NACK indication via a broadcast message (e.g., SIB) or via dedicated RRC signaling indicating that one or more first random access preambles may be used to indicate NACK and / or one or more second random access preambles may be used to indicate ACK.

[0149] In some examples, the random access preamble used for the random access process may indicate that the start of the random access process may be for providing HARQ feedback.

[0150] In some examples, the indication of HARQ feedback may be based on message 3 of the four-step random access process. For example, the payload of message 3 may indicate HARQ feedback.

[0151] In some examples, the indication of HARQ feedback may be based on message A of a two-step random access process. For example, the payload of message A may indicate HARQ feedback.

[0152] In an example embodiment as shown in FIG. 22, based on the decision to transmit HARQ feedback for a transport block and based on the UE being in an RRC idle or RRC inactive state, the UE may transmit HARQ feedback or may transmit an indication of HARQ feedback using an uplink control channel. The UE may transmit HARQ feedback or may transmit an indication of HARQ feedback using an uplink control channel while remaining in an RRC idle or RRC inactive state. The uplink control channel may be commonly configured for a group of UEs (e.g., for a group of UEs in an RRC idle and / or RRC inactive state). In some examples, the UE may receive configuration parameters for the uplink control channel via a broadcast message (e.g., SIB). The configuration parameters may indicate radio resources for the uplink control channel.

[0153] In an example embodiment as shown in FIG. 23, a UE may receive a logical control channel (e.g., a multicast control channel (MCCH)) associated with an MBS service. The UE may receive the logical control channel over a physical downlink data channel (e.g., a PDSCH). The downlink data channel associated with the MBS service may be associated with a first RNTI (e.g., an SC-RNTI). In some examples, the UE may receive scheduling information for reception of a downlink data channel used for transmission of the logical control channel, for example, based on one or more broadcast messages (e.g., SIB messages). The logical control channel may carry control information for receiving the MBS service. For example, the control information may include CSI configuration parameters associated with the MBS service. The CSI configuration parameters may include parameters for CSI measurement and CSI reporting. For example, the CSI configuration parameters may indicate radio resources for CSI measurement and CSI reporting. The CSI reporting may be associated with the MBS service and may be used by the base station for scheduling and transmission of the MBS data. The UE may measure one or more reference signals based on the CSI configuration parameters indicated by the CSI configuration parameters (e.g., carried by the MCCH). The UE may transmit a CSI report based on the CSI measurements and based on the CSI configuration parameters (e.g., carried by the MCCH). In one example, the UE may transmit a CSI report based on a DCI indicating a request / trigger for transmission of a CSI report (e.g., an aperiodic CSI report) or based on radio resources for periodic CSI reporting (e.g., configured by the CSI configuration parameters).

[0154] In an example embodiment as shown in FIG. 24, the UE may receive one or more messages (e.g., one or more RRC messages, one or more broadcast messages, etc.) that include CSI configuration parameters. The CSI configuration parameters may include CSI configuration parameters for measuring a first CSI reference signal and / or a first CS associated with the MBS service. The CSI configuration parameters may include first CSI configuration parameters for reporting the I report associated with the one or more unicast services. The CSI configuration parameters may include second CSI configuration parameters for measuring a second CSI reference signal and / or for reporting a second CSI report associated with the one or more unicast services. The UE may measure the one or more first reference signals based on the first CSI configuration parameters. For example, the first CSI configuration parameters may indicate first radio resources of the one or more first reference signals, and the UE may measure the one or more first reference signals by measuring the first radio resources. The UE may measure the one or more second reference signals based on the second CSI configuration parameters. For example, the second CSI configuration parameters may indicate second radio resources of the one or more second reference signals, and the UE may measure the one or more second reference signals by measuring the second radio resources. The UE may generate a first CSI report associated with the one or more MBS services based on the measurements of the one or more first reference signals. The UE may generate a second CSI report associated with one or more unicast services based on measurements of one or more second reference signals. In some examples, the transmission of the first CSI report and / or the transmission of the second CSI report may be based on receiving one or more DCIs indicating a request / triggering for the transmission of the first CSI report and / or the transmission of the second CSI report. For example, a CSI request field of the one or more DCIs may indicate a request / triggering for the transmission of the first CSI report and / or the transmission of the second CSI report. In some examples, the transmission of the first CSI report and / or the transmission of the second CSI report may be based on a periodic CSI report. For example, the first CSI configuration parameter or the second CSI configuration parameter may indicate a radio resource for the first CSI report or the second CSI report.

[0155] In one embodiment, a user equipment (UE) may determine that a received power level of a reference signal is greater than a threshold. The UE may receive a Multicast Broadcast Service (MBS) transport block from a base station via a downlink data channel. The UE may transmit HARQ feedback associated with the MBS transport block to the base station based on the received power level of the reference signal being greater than the threshold.

[0156] In some embodiments, the UE may receive a retransmission of the MBS transport block based on the HARQ feedback being a negative acknowledgement.

[0157] In some embodiments, transmitting the HARQ feedback associated with the transport block may be further based on the HARQ feedback being a negative acknowledgement.

[0158] In some embodiments, a user equipment (UE) may be in a radio resource control (RRC) connected state.

[0159] In some embodiments, a user equipment (UE) may be in one of a radio resource control (RRC) inactive state and an RRC idle state.

[0160] In some embodiments, the UE may receive a configuration parameter indicating a radio resource of a reference signal. The UE may measure the reference signal using the configuration parameter. In some embodiments, receiving the configuration parameter may be via one of a broadcast message and a radio resource control (RRC) dedicated message. In some embodiments, the broadcast message may be a system information block (SIB) message.

[0161] In some embodiments, the UE may receive a configuration parameter indicating the threshold. In some embodiments, receiving the configuration parameter may be via one of a broadcast message and a radio resource control (RRC) dedicated message. The broadcast message may be a system information block (SIB) message.

[0162] In one embodiment, a user equipment (UE) may receive a multicast broadcast service (MBS) transport block in a radio resource control (RRC) inactive state or an RRC idle state. The UE may determine to transmit HARQ feedback for the received MBS transport block. Based on the determination and based on the UE being in an RRC inactive state or an RRC idle state, the UE may transmit an indication of the HARQ feedback using a random access process.

[0163] In some embodiments, the UE may transition from an RRC inactive state or an RRC idle state to an RRC connected state using a random access process. The UE may transmit HARQ feedback for the MBS transport block after transitioning to the RRC connected state. The UE may transmit HARQ feedback after transitioning to the RRC connected state via an uplink control channel.

[0164] In some embodiments, the random access process may include transmitting a random access preamble, which may indicate HARQ feedback. In some embodiments, the user equipment (UE) may remain in a radio resource control (RRC) inactive state or an RRC idle state after transmitting the random access preamble.

[0165] In some embodiments, the UE may receive a configuration parameter indicating that the one or more first random access preambles are for a negative acknowledgement. In some embodiments, the UE may receive a configuration parameter indicating that the one or more second random access preambles are for a positive acknowledgement. In some embodiments, the UE may receive a broadcast message including the configuration parameter. In some embodiments, the broadcast message may be a system information block (SIB) message.

[0166] In some embodiments, the random access process may be a two-step random access process. The transmission of the indication of HARQ feedback may be based on message A of the random access process.

[0167] In some embodiments, the random access process may be a four-step random access process. The transmission of the indication of HARQ feedback may be based on message 3 of the random access process.

[0168] In some embodiments, the user equipment (UE) may remain in a radio resource control (RRC) inactive state or an RRC idle state after transmission of the HARQ feedback indication.

[0169] In some embodiments, the random access process may include transmitting a random access preamble that indicates that the random access process is for providing HARQ feedback.

[0170] In some embodiments, the HARQ feedback may be a negative acknowledgment.

[0171] In some embodiments, the determination to transmit HARQ feedback for the received MBS transport block may be based on the HARQ feedback being a negative acknowledgement.

[0172] In one embodiment, a UE in a radio resource control (RRC) inactive state or an RRC idle state may receive a multicast broadcast service (MBS) transport block. The UE may determine to transmit HARQ feedback for the received MBS transport block. Based on the determination and based on the UE being in an RRC inactive state or an RRC idle state, the UE may transmit an indication of the HARQ feedback using an uplink control channel, which may be a common uplink control channel for multiple UEs in an RRC inactive state or an RRC idle state.

[0173] In some embodiments, the UE may receive one or more broadcast messages including configuration parameters for the uplink control channel. In some embodiments, the one or more broadcast messages may include a system information block (SIB) message. In some embodiments, the configuration parameters may indicate radio resources for the uplink control channel.

[0174] In some embodiments, the HARQ feedback may be a negative acknowledgment.

[0175] In some embodiments, the determination to transmit HARQ feedback for the received MBS transport block may be based on the HARQ feedback being a negative acknowledgement.

[0176] In some embodiments, transmitting the indication of HARQ feedback may be while remaining in an RRC inactive state or an RRC idle state.

[0177] In one embodiment, the UE may receive a logical control channel associated with a Multicast Broadcast Service (MBS) service over the downlink data channel, where the logical control channel may carry control information including CSI configuration parameters for CSI measurements and CSI reports, where the CSI reports may be associated with the MBS service. The UE may measure one or more reference signals based on the CSI configuration parameters. The UE may transmit a CSI report based on the measurements of the reference signals and based on the CSI configuration parameters.

[0178] In some embodiments, the logical control channel may be a logical multicast control channel (MCCH). In some embodiments, the UE may receive scheduling information for reception of the MCCH.

[0179] In some embodiments, the control information may further include scheduling information for reception of a Multicast Broadcast Service (MBS).

[0180] In some embodiments, a channel state information (CSI) configuration parameter may indicate radio resources for one or more reference signals.

[0181] In some embodiments, the UE may receive downlink control information indicating a request for transmission of a channel state information (CSI) report.

[0182] In some embodiments, the UE may transmit a channel state information (CSI) report based on a periodic CSI resource. The CSI configuration parameter may indicate periodic CSI reporting.

[0183] In one embodiment, a user equipment (UE) receives CSI configuration parameters including a first CSI configuration parameter associated with a multicast broadcast service (MBS) service and a second CSI configuration parameter associated with a unicast service. The UE may measure one or more first reference signals based on the first CSI configuration parameter. The UE may measure one or more second reference signals based on the second CSI configuration parameter. The UE may transmit a first CSI report associated with one or more MBS services based on the measurement of the first reference signal. The UE may transmit a second CSI report associated with one or more unicast services based on the measurement of the second reference signal.

[0184] In some embodiments, the first channel state information (CSI) configuration parameter may indicate a first radio resource of one or more first reference signals, and the second CSI configuration parameter may indicate a second radio resource of one or more second reference signals.

[0185] In some embodiments, the UE may receive first downlink control information indicating a first request for transmission of a first CSI report, and the UE may receive second downlink control information indicating a second request for transmission of a second CSI report.

[0186] The example blocks and modules described in this disclosure with respect to various example embodiments may be implemented or performed using a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. Examples of general purpose processors include, but are not limited to, a microprocessor, any conventional processor, controller, microcontroller, or state machine. In some examples, a processor may be implemented using a combination of devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration).

[0187] The functions described in this disclosure may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. Instructions or code may be stored on or transmitted to a computer-readable medium for implementation of the functions. Other examples for implementation of the functions disclosed herein are also within the scope of this disclosure. Implementation of the functions may be through physically co-located or distributed elements (e.g., in various locations), including being distributed such that portions of the functions are implemented in different physical locations.

[0188] Computer-readable media includes, but is not limited to, non-transitory computer storage media. Non-transitory storage media can be accessed by general-purpose or special-purpose computers. Examples of non-transitory storage media include, but are not limited to, random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), flash memory, compact disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, and the like. Non-transitory media can be used to carry or store desired program code means (e.g., instructions and / or data structures) and can be accessed by general-purpose or special-purpose computers or general-purpose or special-purpose processors. In some examples, the software / program code can be transmitted from a remote source (e.g., a website, a server, etc.) using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave. In such examples, coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are within the definition of media. Combinations of the above examples are also included within the scope of computer-readable media.

[0189] As used in this disclosure, the use of the term "or" in a list of items refers to an inclusive list. A list of items may be preceded by a phrase such as "at least one of" or "one or more of." For example, a list of at least one of A, B, or C includes A or B or C or AB (i.e., A and B) or AC or BC or ABC (i.e., A and B and C). Also, as used in this disclosure, the phrase "based on" preceding a list of conditions should not be construed as "based only on" the set of conditions, but rather as "based at least in part on" the set of conditions. For example, a result described as "based on condition A" could be based on both condition A and condition B without departing from the scope of this disclosure.

[0190] In this specification, the terms "comprise", "include" or "contain" may be used interchangeably, have the same meaning, and should be interpreted as inclusive and open-ended. The terms "comprise", "include" or "contain" may be used before a list of elements to indicate that at least all of the recited elements in the list are present, but other elements not in the list may also be present. For example, if A contains B and C, then both {B,C} and {B,C,D} are within the scope of A.

[0191] The present disclosure describes exemplary configurations in conjunction with the accompanying drawings, which do not represent all examples that may be implemented or all configurations within the scope of the present disclosure. The term "exemplary" should not be interpreted as "preferred" or "advantageous compared to other examples," but rather as "example, instance, or example." By reading this disclosure, including the description of the embodiments and the drawings, it will be understood by those skilled in the art that the technology disclosed herein may be implemented using alternative embodiments. Those skilled in the art will understand that the embodiments described herein, or specific features of the embodiments, may be combined to arrive at yet other embodiments for implementing the technology described in the present disclosure. Thus, the present disclosure is not limited to the examples and designs described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0192] Supplementary Note 1. A method of Hybrid Automatic Repeat Request (HARQ) feedback transmission, comprising: receiving, by a user equipment (UE) via a downlink data channel, a multicast broadcast service (MBS) transport block; determining, by the UE, that a received power level of a reference signal is greater than a predetermined threshold; and transmitting, by the UE, HARQ feedback associated with the received MBS transport block.

[0193] Supplementary Note 2. The method of Supplementary Note 1, wherein the HARQ feedback corresponds to a negative acknowledgment.

[0194] Supplementary Note 3. The method of Supplementary Note 2, further comprising receiving a retransmission of the MBS transport block in response to the HARQ feedback.

[0195] Supplementary Note 4. The method of Supplementary Note 1, wherein the state of the user equipment (UE) corresponds to a radio resource control (RRC) connection state.

[0196] Supplementary Note 5. The method of Supplementary Note 1, wherein the state of the user equipment (UE) corresponds to at least one of a radio resource control (RRC) inactive state and an RRC idle state.

[0197] Receiving a configuration parameter indicating a radio resource of the reference signal; 2. The method of claim 1, further comprising measuring the reference signal using the configuration parameters.

[0198] Supplementary Note 7. The method of Supplementary Note 6, wherein receiving the configuration parameters includes receiving the configuration parameters via one of a broadcast message and a radio resource control (RRC) dedicated message.

[0199] Supplementary Note 8. The method of Supplementary Note 7, wherein the broadcast message is a System Information Block (SIB) message.

[0200] Clause 9. The method of clause 1, further comprising receiving configuration parameters including the predetermined threshold.

[0201] Supplementary Note 10. The method of Supplementary Note 9, wherein receiving the configuration parameters includes receiving the configuration parameters via one of a broadcast message and a Radio Resource Control (RRC) dedicated message.

[0202] Addition 11. The method of Addition 10, wherein the broadcast message is a System Information Block (SIB) message.

[0203] Addition 12. A method of Hybrid Automatic Repeat Request (HARQ) feedback transmission, comprising: receiving, by a user equipment (UE), a multicast broadcast service (MBS) transport block, the UE corresponding to a defined state; determining to transmit HARQ feedback for the received MBS transport block; and transmitting the HARQ feedback using a random access process based on the UE being in the defined state.

[0204] Supplementary Note 13. Transitioning to an RRC connected state using the random access process; 13. The method of claim 12, further comprising: after transitioning to the RRC connected state, transmitting the HARQ feedback for the MBS transport block.

[0205] Supplementary Note 14. The method of Supplementary Note 13, wherein said transmitting the HARQ feedback includes transmitting the HARQ feedback over an uplink control channel.

[0206] Supplementary Note 15. The method of Supplementary Note 12, wherein transmitting the HARQ feedback using a random access process includes transmitting a random access preamble, the random access preamble corresponding to the HARQ feedback.

[0207] Supplementary Note 16. The method of Supplementary Note 15, wherein the user equipment (UE) remains in the defined state after transmitting the random access preamble.

[0208] Supplementary Note 17. The method of Supplementary Note 12, further comprising receiving, by the UE, configuration parameters.

[0209] Supplementary Note 18. The method of Supplementary Note 17, wherein receiving the configuration by the UE includes receiving a configuration parameter indicating that one or more first random access preambles are for a negative acknowledgement.

[0210] Supplementary Note 19. The method of Supplementary Note 17, wherein receiving configuration parameters by the UE includes receiving a configuration parameter indicating that one or more second random access preambles are for acknowledgment.

[0211] Supplementary Note 20. The method of Supplementary Note 17, wherein receiving, by the UE, the configuration parameters includes receiving a broadcast message including the configuration parameters.

[0212] Addition 21. The method of addition 20, wherein the broadcast message is a system information block (SIB) message.

[0213] Addendum 22. The method of Addendum 12, wherein the random access process is a two-step random access process.

[0214] Addition 23. The method of addition 22, wherein the transmission of the indication of hybrid automatic repeat request (HARQ) feedback is based on message A of the two-step random access process.

[0215] Addendum 24. The method of Addendum 12, wherein the random access process is a four-step random access process.

[0216] Addendum 25. The method of Addendum 24, wherein the transmission of the indication of Hybrid Automatic Repeat Request (HARQ) feedback is based on message 3 of the four-step random access process.

[0217] Supplementary Note 26. The method of Supplementary Note 12, wherein the defined states include at least one of a radio resource control (RRC) inactive state or an RRC idle state.

[0218] Addition 27. The method of Addition 12, wherein the Hybrid Automatic Repeat Request (HARQ) feedback includes a negative acknowledgment.

[0219] Supplementary Note 28. The method of Supplementary Note 12, wherein determining to transmit the HARQ feedback for the received Multicast Transport Service (MBS) transport block is based on the HARQ feedback being a negative acknowledgement.

[0220] Addition 29. A method of hybrid automatic repeat request (HARQ) feedback transmission, comprising: receiving a Multicast Broadcast Service (MBS) transport block by a user equipment (UE) in a defined Radio Resource Control (RRC) state; determining to transmit HARQ feedback for the received MBS transport block; transmitting an indication of the HARQ feedback using an uplink control channel based on the UE being in the defined state, the uplink control channel being a common uplink control channel for use by multiple UEs in the defined state.

[0221] Supplementary Note 30. The method of Supplementary Note 29, further comprising receiving, by the user equipment (UE), one or more broadcast messages including configuration parameters for the uplink control channel.

[0222] Addition 31. The method of Addition 30, wherein the one or more broadcast messages include a system information block (SIB) message.

[0223] Addition 32. The method of Addition 28, wherein the configuration parameters indicate the radio resources of the uplink control channel.

[0224] Addendum 33. The method of Addendum 29, wherein the HARQ feedback includes a negative acknowledgement.

[0225] Supplementary Note 34. The method of Supplementary Note 29, wherein determining to transmit HARQ feedback for the received MBS transport block includes determining to transmit the HARQ feedback if the HARQ feedback includes a negative acknowledgement.

[0226] Supplementary Note 35. The method of Supplementary Note 29, wherein transmitting the indication of HARQ feedback occurs while the UE remains in the defined state.

[0227] Addition 36. A method for channel state information (CSI) feedback reporting, comprising: receiving a logical control channel associated with a Multicast Broadcast Service (MBS) service over a downlink data channel, the logical control channel carries control information including CSI configuration parameters for CSI measurement and CSI reporting; receiving the CSI report associated with the MBS service; measuring one or more reference signals based on the CSI configuration parameters; and transmitting a CSI report based on the measurement of the reference signal and the CSI configuration parameters.

[0228] Addendum 37. The method of Addendum 36, wherein the logical control channel is a logical multicast control channel (MCCH).

[0229] Addendum 38. The method of Addendum 37, further comprising receiving scheduling information for reception of the logical multicast control channel (MCCH).

[0230] Addendum 39. The method of Addendum 36, wherein the control information further includes scheduling information for reception of a Multicast Broadcast Service (MBS).

[0231] Addition 40. The method of Addition 36, wherein a channel state information (CSI) configuration parameter indicates radio resources for the one or more reference signals.

[0232] Supplementary Note 41. The method of Supplementary Note 36, further comprising the user equipment (UE) receiving downlink control information indicating a request for transmission of the channel state information (CSI) report.

[0233] Supplementary Note 42. The method of Supplementary Note 36, wherein transmitting the channel state information (CSI) report includes transmitting the CSI report based on a periodic CSI resource, and the CSI configuration parameters include the periodic CSI resource.

[0234] Addition 43. A method for channel state information (CSI) feedback reporting, comprising: receiving, by a user equipment (UE), CSI configuration parameters, the CSI configuration parameters comprising: The first associated with the Multicast Broadcast Service (MBS) service CSI configuration parameters; and a second CSI configuration parameter associated with the unicast service. measuring one or more first reference signals based on the first CSI configuration parameters; measuring one or more second reference signals based on the second CSI configuration parameters; transmitting a first CSI report associated with one or more MBS services based on the measurement of the first reference signal; and transmitting a second CSI report associated with one or more unicast services based on the measurement of the second reference signal.

[0235] Addition 44. The first channel state information (CSI) configuration parameter indicates a first radio resource of the one or more first reference signals; 44. The method of claim 43, wherein the second CSI configuration parameter indicates a second radio resource for the one or more second reference signals.

[0236] Addition 45. Receiving, by the user equipment (UE), first downlink control information indicating a first request for transmission of the first channel state information (CSI) report; 44. The method of claim 43, further comprising receiving second downlink control information indicating a second request for transmission of the second CSI report.

[0237] Addendum 46. An apparatus for use in wireless communications, comprising: an antenna for use in transmitting electromagnetic signals; a memory for maintaining computer readable code; a processor for executing the computer readable code, the computer readable code configuring the apparatus to: receiving a Multicast Broadcast Service (MBS) transport block, the UE corresponding to a defined state; determining to transmit HARQ feedback for the received MBS transport block; and transmitting the HARQ feedback using a random access process based on the UE being in the defined state.

[0238] Addendum 47. The device comprises: transitioning to an RRC connected state using the random access procedure; 47. The apparatus of claim 46, further configured for: after transitioning to the RRC connected state, transmitting the HARQ feedback for the MBS transport block.

[0239] Supplementary Note 48. The apparatus of Supplementary Note 47, wherein the apparatus transmits the HARQ feedback over an uplink control channel.

[0240] Supplementary Note 49. The apparatus of Supplementary Note 46, wherein the apparatus transmits a random access preamble, the random access preamble corresponding to the HARQ feedback.

[0241] Clause 50. The apparatus of claim 49, wherein the apparatus remains in the defined state after transmitting the random access preamble.

[0242] Clause 51. The apparatus of clause 46, wherein the apparatus receives configuration parameters.

[0243] Addendum 52. The apparatus of Addendum 51, wherein the configuration parameter indicates that the one or more first random access preambles are for a negative acknowledgement.

[0244] Addendum 53. The apparatus of Addendum 51, wherein the configuration parameter indicates that the one or more second random access preambles are for positive acknowledgement.

[0245] Clause 54. The apparatus of clause 51, wherein the apparatus receives a broadcast message including the configuration parameters.

[0246] Addition 55. The apparatus of Addition 54, wherein the broadcast message is a system information block (SIB) message.

[0247] Clause 56. The apparatus of Clause 46, wherein the random access process is a two-step random access process.

[0248] Addition 57. The apparatus of Addition 56, wherein the transmission of the indication of hybrid automatic repeat request (HARQ) feedback is based on message A of the two-step random access process.

[0249] Clause 58. The apparatus of Clause 46, wherein the random access process is a four-step random access process.

[0250] Addition 59. The apparatus of Addition 46, wherein the transmission of the indication of Hybrid Automatic Repeat Request (HARQ) feedback is based on message 3 of the four-step random access process.

[0251] Clause 60. The apparatus of clause 46, wherein the defined states include at least one of a radio resource control (RRC) inactive state or an RRC idle state.

[0252] Addition 61. The apparatus of Addition 46, wherein the HARQ feedback includes a negative acknowledgment.

[0253] Supplementary Note 62. The apparatus of Supplementary Note 46, wherein the apparatus transmits the HARQ feedback for the received Multicast Transport Service (MBS) transport block based on the HARQ feedback being a negative acknowledgement.

[0254] Addendum 63. An apparatus for use in wireless communications, comprising: an antenna for use in transmitting electromagnetic signals; a memory for maintaining computer readable code; a processor for executing the computer readable code, the computer readable code configuring the device to: receiving, via a downlink data channel, a logical control channel associated with a Multicast Broadcast Service (MBS) service, the logical control channel carrying control information including CSI configuration parameters for CSI measurements and CSI reports, the CSI reports being associated with the MBS service; measuring one or more reference signals based on the CSI configuration parameters; and transmitting a CSI report based on the measurements of the reference signals and the CSI configuration parameters.

[0255] Supplementary Note 64. The logical control channel is a logical multicast control channel (MCCH). 64. The apparatus of claim 63.

[0256] Addition 65. The apparatus of Addition 63, wherein the apparatus receives scheduling information for reception of the logical multicast control channel (MCCH).

[0257] Addendum 66. The apparatus of Addendum 63, wherein the control information further includes scheduling information for reception of a Multicast Broadcast Service (MBS).

[0258] Addition 67. The apparatus of Addition 63, wherein a channel state information (CSI) configuration parameter indicates radio resources for the one or more reference signals.

[0259] Appendix 68. The apparatus of Appendix 63, wherein the apparatus receives downlink control information indicating a request for transmission of the channel state information (CSI) report.

[0260] Supplementary Note 69. The apparatus of Supplementary Note 63, wherein the apparatus transmits the CSI report based on a periodic CSI resource, and the CSI configuration parameters include the periodic CSI resource.

[0261] 70. The method of claim 43, further comprising receiving downlink control information indicating a request for transmission of at least one of the first CSI report or the second CSI report by the UE.

[0262] Supplementary Note 71. The method of Supplementary Note 43, further comprising generating, by the UE, the first CSI report and the second CSI report.

[0263] Addendum 72. A base station for a mobile communication system, comprising: A memory for storing instructions; and a processor configured to execute the instructions to transmit channel state information (CSI) configuration parameters to a user equipment (UE), the channel state information (CSI) configuration parameters including a first CSI configuration parameter associated with a multicast broadcast service (MBS) and a second CSI configuration parameter associated with a unicast service; the UE is configured to measure one or more first reference signals based on the first CSI configuration parameters and to measure one or more second reference signals based on the second CSI configuration parameters.

[0264] 73. The base station of claim 72, wherein the processor is configured to execute the instructions to transmit downlink control information indicating a request for transmission of at least one of the first CSI report or the second CSI report.

[0265] 74. The base station of claim 72, wherein the downlink control information triggers the UE to generate at least one of the first CSI report or the second CSI report.

[0266] A method of hybrid automatic repeat request (HARQ) feedback reception, comprising: transmitting, by a base station, a multicast broadcast service (MBS) transport block over a downlink data channel; receiving, by the base station, HARQ feedback associated with the transmitted MBS transport block.

[0267] A method for receiving Hybrid Automatic Repeat Request (HARQ) feedback, comprising: , transmitting, by a base station, a Multicast Broadcast Service (MBS) transport block that can be received by a user equipment (UE) corresponding to a defined state; receiving HARQ feedback for the MBS transport block transmitted based on the UE being in the defined state, wherein the MBS transport block is transmitted by transmitting the HARQ feedback using a random access process.

[0268] A method of hybrid automatic repeat request (HARQ) feedback reception, comprising: transmitting, by a base station, a Multicast Broadcast Service (MBS) transport block that is receivable by a user equipment (UE) that is in a defined Radio Resource Control (RRC) state; and receiving an indication of the HARQ feedback using an uplink control channel, the indication being transmitted based on the UE being in the defined state, the uplink control channel being a common uplink control channel for use by multiple UEs.

[0269] Addition 78. A method of channel state information (CSI) feedback reception, comprising: transmitting, by a base station, a logical control channel associated with a multicast broadcast service (MBS) over a downlink data channel, the logical control channel carrying control information including CSI configuration parameters for CSI measurements and CSI reports, the CSI reports being associated with the MBS; transmitting one or more reference signals; and receiving a CSI report based on the measurement of at least one of the one or more reference signals and the CSI configuration parameter.

[0270] Addition 79. A method of channel state information (CSI) feedback reception, comprising: Transmitting, by a base station, a CSI configuration parameter, the CSI configuration parameter comprising: a first CSI configuration parameter associated with a multicast broadcast service (MBS); and a second CSI configuration parameter associated with the unicast service. transmitting one or more first reference signals based on the first CSI configuration parameter; transmitting one or more second reference signals based on the second CSI configuration parameters; receiving a first CSI report associated with one or more MBSs based on a measurement of at least one of the one or more first reference signals; and receiving a second CSI report associated with one or more unicast services based on the measurement of at least one of the one or more second reference signals.

[0271] This application claims the benefit of U.S. Provisional Application No. 63 / 090,409, entitled "FEEDBACK ENHANCEMENT FOR MULTICAST BROADCAST SERVICES," filed on October 12, 2020. U.S. Provisional Application No. 63 / 090,409 is incorporated herein by reference.

Claims

1. 1. A method for Hybrid Automatic Repeat Request (HARQ) feedback transmission, comprising: receiving, by a user equipment (UE) via a downlink data channel, a Multicast Broadcast Service (MBS) transport block; determining, by the UE, that a received power level of a reference signal is greater than a predefined threshold; and transmitting, by the UE, HARQ feedback associated with the received MBS transport block.

2. The method of claim 1 , wherein the HARQ feedback corresponds to a negative acknowledgment.

3. The method of claim 2 , further comprising receiving a retransmission of the MBS transport block in response to the HARQ feedback.

4. The method of claim 1 , wherein the user equipment (UE) state corresponds to a radio resource control (RRC) connected state.

5. 2. The method of claim 1, wherein the state of the user equipment (UE) corresponds to at least one of a radio resource control (RRC) inactive state and an RRC idle state.

6. receiving a configuration parameter indicative of a radio resource of the reference signal; The method of claim 1 , further comprising: measuring the reference signal using the configuration parameters.

7. The method of claim 6 , wherein receiving the configuration parameters comprises receiving the configuration parameters via one of a broadcast message and a radio resource control (RRC) dedicated message.

8. The method of claim 7 , wherein the broadcast message is a system information block (SIB) message.

9. The method of claim 1 , further comprising receiving a configuration parameter comprising the predetermined threshold.

10. 10. The method of claim 9, wherein receiving the configuration parameters comprises receiving the configuration parameters via one of a broadcast message and a radio resource control (RRC) dedicated message.

11. The method of claim 10 , wherein the broadcast message is a system information block (SIB) message.

12. 1. A method for Hybrid Automatic Repeat Request (HARQ) feedback transmission, comprising: receiving, by a user equipment (UE), a Multicast Broadcast Service (MBS) transport block, the UE corresponding to a defined state; determining to transmit HARQ feedback for the received MBS transport block; and transmitting the HARQ feedback using a random access process based on the UE being in the defined state.

13. transitioning to an RRC connected state using the random access procedure; The method of claim 12, further comprising: after transitioning to the RRC connected state, transmitting the HARQ feedback for the MBS transport block.

14. The method of claim 13 , wherein the transmitting the HARQ feedback comprises transmitting the HARQ feedback over an uplink control channel.

15. The method of claim 12 , wherein transmitting the HARQ feedback using a random access process includes transmitting a random access preamble, the random access preamble corresponding to the HARQ feedback.

16. The method of claim 15, wherein the user equipment (UE) remains in the defined state after transmitting the random access preamble.

17. The method of claim 12 , further comprising receiving, by the UE, configuration parameters.

18. 20. The method of claim 17, wherein receiving the configuration by the UE includes receiving a configuration parameter indicating that one or more first random access preambles are for a negative acknowledgement.

19. 20. The method of claim 17, wherein receiving, by the UE, a configuration parameter includes receiving a configuration parameter indicating that the one or more second random access preambles are for acknowledgment.

20. The method of claim 17 , wherein receiving, by the UE, the configuration parameters comprises receiving a broadcast message including the configuration parameters.

21. 21. The method of claim 20, wherein the broadcast message is a system information block (SIB) message.

22. The method of claim 12 , wherein the random access process is a two-step random access process.

23. 23. The method of claim 22, wherein the transmission of the indication of the Hybrid Automatic Repeat Request (HARQ) feedback is based on message A of the two-step random access process.

24. The method of claim 12 , wherein the random access process is a four-step random access process.

25. 25. The method of claim 24, wherein the transmission of the indication of Hybrid Automatic Repeat Request (HARQ) feedback is based on message 3 of the four-step random access process.

26. 13. The method of claim 12, wherein the defined state includes at least one of a radio resource control (RRC) inactive state or the RRC idle state.

27. The hybrid automatic repeat request (HARQ) feedback includes a negative acknowledgment. Item 13. The method according to item 12.

28. 13. The method of claim 12, wherein determining to transmit the HARQ feedback for the received Multicast Transport Service (MBS) transport block is based on the HARQ feedback being a negative acknowledgement.

29. 1. A method for Hybrid Automatic Repeat Request (HARQ) feedback transmission, comprising: receiving a Multicast Broadcast Service (MBS) transport block by a user equipment (UE) in a defined Radio Resource Control (RRC) state; determining to transmit HARQ feedback for the received MBS transport block; transmitting an indication of the HARQ feedback using an uplink control channel based on the UE being in the defined state, the uplink control channel being a common uplink control channel for use by multiple UEs in the defined state.

30. 30. The method of claim 29, further comprising receiving, by the user equipment (UE), one or more broadcast messages including configuration parameters for the uplink control channel.

31. 31. The method of claim 30, wherein the one or more broadcast messages include a system information block (SIB) message.

32. 30. The method of claim 28, wherein the configuration parameters indicate the radio resources of the uplink control channel.

33. 30. The method of claim 29, wherein the HARQ feedback comprises a negative acknowledgment.

34. 30. The method of claim 29, wherein determining to transmit HARQ feedback for the received MBS transport block comprises determining to transmit the HARQ feedback if the HARQ feedback includes a negative acknowledgement.

35. 30. The method of claim 29, wherein transmitting the indication of the HARQ feedback occurs while the UE remains in the defined state.

36. 1. A method for Hybrid Automatic Repeat Request (HARQ) feedback reception, comprising: transmitting, by a base station, a Multicast Broadcast Service (MBS) transport block over a downlink data channel; receiving, by the base station, HARQ feedback associated with the transmitted MBS transport block.

37. 1. A method for Hybrid Automatic Repeat Request (HARQ) feedback reception, comprising: transmitting, by a base station, a Multicast Broadcast Service (MBS) transport block that can be received by a user equipment (UE) corresponding to a defined state; receiving HARQ feedback for the MBS transport block transmitted based on the UE being in the defined state, the MBS transport block receiving the HARQ feedback using a random access process. The method is transmitted by transmitting a block.

38. 1. A method for channel state information (CSI) feedback reception, comprising: Transmitting, by a base station, a logical control channel associated with a multicast broadcast service (MBS) via a downlink data channel, the logical control channel carrying control information including CSI configuration parameters for CSI measurement and CSI reporting, the CSI reporting being associated with the MBS; Transmitting one or more reference signals; receiving a CSI report based on measurements of at least one of the one or more reference signals and the CSI configuration parameters.

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