Feedback extension for multicast broadcast services

Abstract

Providing a Hybrid Automatic Resend Request (HARQ) feedback transmission method. [Solution] The HARQ feedback transmission method includes: the UE receiving MBS data from a base station via a downlink data channel; the UE receiving first information from the base station to determine whether to transmit HARQ feedback to the MBS data before receiving the MBS data; the UE determining whether to transmit HARQ feedback to the MBS data based on the first information; and the UE transmitting HARQ feedback to the MBS data in accordance with the determination.

Description

Technical Field

[0001] The present disclosure relates to a method for hybrid automatic repeat request (HARQ) feedback transmission and a method for channel state information (CSI) feedback reporting.

Background Art

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

[0003] A wireless communication network can include components for accessing the wireless communication network or can include a variety of devices accessing it. Such devices can utilize the wireless communication network to facilitate interaction with other devices that can access the wireless communication network or to facilitate interaction with devices utilizing other communication networks via the wireless communication network.

Summary of the Invention

[0004] In some embodiments of the present disclosure, a method for hybrid automatic repeat request (HARQ) feedback transmission is provided. The method includes receiving, from a base station, a multicast broadcast service (MBS) transport block via a downlink data channel, determining that a received power level of a reference signal is greater than a predetermined threshold, and transmitting HARQ feedback associated with the received MBS transport block.

[0005] In some embodiments of the present disclosure, a method for hybrid automatic retransmission request (HARQ) feedback transmission is provided. The method includes: a UE receiving a multicast broadcast service (MBS) transport block corresponding to a defined state; the UE deciding 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 a defined state.

[0006] In some embodiments of the present disclosure, a method for reporting channel status information (CSI) feedback is provided. The method 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 measurement and CSI reporting, the CSI report being associated with the MBS, and measuring one or more reference signals by a UE 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 this disclosure, a method for reporting channel status information (CSI) feedback is provided. The method involves receiving CSI configuration parameters, the CSI configuration parameters being a first CSI configuration parameter associated with a multicast broadcast service (MBS) and a second CSI configuration parameter associated with a unicast service. The system includes receiving, measuring one or more first reference signals based on a first CSI configuration parameter, measuring one or more second reference signals based on a second CSI configuration parameter, transmitting a first CSI report associated with one or more MBS based on the measurement of the first reference signals, and transmitting a second CSI report associated with one or more unicast services based on the measurement of the second reference signals.

[0008] In some embodiments of the present disclosure, a device for a mobile communications network is provided. The device includes a memory for storing instructions and a processor configured to execute instructions, and by executing the instructions, it receives channel state information (CSI) configuration parameters, the CSI configuration parameters include a first CSI configuration parameter associated with a multicast broadcast service (MBS) and a second CSI configuration parameter associated with a unicast service; 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 one or more MBS based on the measurement of the first reference signals; and transmits a second CSI report associated with 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. The system includes a base station configured to transmit CSI configuration parameters to a user terminal (UE), including first channel state information (CSI) configuration parameters associated with a multicast broadcast service (MBS) and second CSI configuration parameters associated with a unicast service; and a UE configured to measure one or more first reference signals based on the first CSI configuration parameters and one or more second reference signals based on the second CSI configuration parameters.

[0010] In some embodiments of the present disclosure, a non-temporary computer-readable medium is provided. The non-temporary computer-readable medium stores a set of instructions that can be executed 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 parameter; measuring one or more second reference signals based on the second CSI configuration parameter; transmitting a first CSI report associated with one or more MBS based on the measurement of the first reference signals; and transmitting a second CSI report associated with one or more unicast services based on the measurement of the second reference signals.

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

[0012] [Figure 1] An example of a mobile communications system according to some aspects of one or more exemplary embodiments of this disclosure is shown. [Figure 2]Figures 2A and 2B show examples of wireless protocol stacks for a user plane according to some aspects of one or more exemplary embodiments of the present disclosure. [Figure 3] Figures 3A, 3B, and 3C illustrate exemplary mappings between logical channels and transport channels in a downlink according to some aspects of one or more exemplary embodiments of the present disclosure. [Figure 4] Figures 4A, 4B, and 4C show exemplary mappings between transport channels and physical channels in a downlink according to some aspects of one or more exemplary embodiments of the present disclosure. [Figure 5] Figures 5A, 5B, 5C, and 5D show examples of radio protocol stacks for NR sidelink communication according to some aspects of one or more exemplary embodiments of the present disclosure. [Figure 6] The following are exemplary physical signals in the downlink, uplink, and sidelink according to some aspects of one or more exemplary embodiments of the present disclosure. [Figure 7] Examples of radio resource control (RRC) states and transitions between different RRC states are shown in some aspects of one or more exemplary embodiments of the present disclosure. [Figure 8] This document illustrates exemplary frame structures and physical resources according to some aspects of one or more exemplary embodiments of the present disclosure. [Figure 9] This disclosure shows exemplary component carrier configurations in different carrier aggregation scenarios according to some aspects of one or more exemplary embodiments of this disclosure. [Figure 10] This document illustrates exemplary bandwidth subconfigurations and switching configurations according to some aspects of one or more exemplary embodiments of the present disclosure. [Figure 11] This disclosure illustrates an exemplary four-step competition-based and non-competitive random access process according to some aspects of one or more exemplary embodiments of this disclosure. [Figure 12]An exemplary two-step contention-based and contention-free random access process according to some aspects of one or more exemplary embodiments of the present disclosure is shown. [Figure 13] 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 is shown. [Figure 14] An example of SSB burst transmission according to some aspects of one or more exemplary embodiments of the present disclosure is shown. [Figure 15] Exemplary components of a user terminal and a base station for transmission and / or reception according to some aspects of one or more exemplary embodiments of the present disclosure are shown. [Figure 16] An exemplary process according to some aspects of one or more exemplary embodiments of the present disclosure is shown. [Figure 17] An exemplary process according to some aspects of one or more exemplary embodiments of the present disclosure is shown. [Figure 18] An exemplary process according to some aspects of one or more exemplary embodiments of the present disclosure is shown. [Figure 19] An exemplary process according to some aspects of one or more exemplary embodiments of the present disclosure is shown. [Figure 20] An exemplary process according to some aspects of one or more exemplary embodiments of the present disclosure is shown. [Figure 21] An exemplary process according to some aspects of one or more exemplary embodiments of the present disclosure is shown. [Figure 22] An exemplary process according to some aspects of one or more exemplary embodiments of the present disclosure is shown. [Figure 23] An exemplary process according to some aspects of one or more exemplary embodiments of the present disclosure is shown. [Figure 24] An exemplary process according to some aspects of one or more exemplary embodiments of the present disclosure is shown.

Mode for Carrying Out the Invention

[0013] The following disclosure provides many different embodiments or examples for implementing different features of the provided subject matter. To simplify the present disclosure, specific examples of the configuration 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, without departing from the scope of the embodiment, the first element can be referred to as the second element, and similarly, the second element can be referred to as the first element.

[0015] FIG. 1 shows 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 can 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 can provide services such as voice, data (e.g., wireless Internet access), messaging, vehicle communication services such as vehicle-to-everything (V2X) communication services, security services, mission-critical services, services in residential, commercial or industrial environments such as IoT, industrial IoT (IIoT), etc.

[0016] The mobile communication system 100 can enable various types of applications with different requirements regarding latency, reliability, throughput, etc. Examples of supported applications include enhanced mobile broadband (eMBB), ultra-high reliability low latency communication (URLLC), and massive machine-type communication (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 regarding latency and reliability, and moderate requirements regarding data rates. An exemplary mMTC application includes a network of a huge number of IoT devices that are only sporadically active and transmit small data payloads.

[0017] A mobile communications system 100 may include a radio access network (RAN) portion and a core network portion. The example shown in Figure 1 illustrates a next-generation RAN (NG-RAN) 105 and a 5G core network (5GC) 110 as examples of the RAN and core network, respectively. Other examples of RANs and core networks may be implemented without departing from the scope of this disclosure. Other examples of RANs include an advanced universal terrestrial radio access network (EUTRAN) and a universal terrestrial radio access network (UTRAN). Other examples of core networks include an advanced packet core (EPC) and a UMTS core network (UCN). The RAN implements radio access technology (RAT) and resides between user terminals (UEs) 125 (e.g., UE125A to UE125E) 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), and Universal Mobile Telecommunication System (UMTS). The RAT of an exemplary mobile communications system 100 may be NR. The core network exists between the RAN and one or more external networks (e.g., data networks) and handles mobility management, authentication, session management, and bearer management. It is responsible for functions such as networking and the application of different quality of service (QoS). The functional layer between UE125 and RAN (e.g., NG-RAN105) is sometimes referred to as the access layer (AS), and the functional layer between UE125 and the core network (e.g., 5GC110) is sometimes referred to as the non-access layer (NAS).

[0018] UE125 may include wireless transmission and reception components for communication with one or more nodes in the RAN, one or more relay nodes, or one or more other UEs. Examples of UE125 include, but are not limited to, smartphones, tablets, laptops, computers, wireless transmission and / or reception units in vehicles, V2X or vehicle-to-vehicle (V2V) devices, wireless sensors, IoT devices, IIoT devices, etc. Other names may be used for UE125, such as mobile station (MS), terminal equipment, terminal node, client device, and mobile device. Furthermore, UE125 may also include components or sub-components integrated into other devices, such as vehicles, to provide wireless communication capabilities with nodes in the RAN, other UEs, and satellite communications, as described herein. Such other devices may have other functions or more functions in addition to wireless communication. Thus, references to UE may include individual components that enable wireless communication, as well as entire devices incorporating components that enable wireless communication.

[0019] A RAN may include nodes (e.g., base stations) for communication with the UE. For example, the NG-RAN 105 of the mobile communication system 100 may include nodes for communication with the UE 125. Different names may be used for RAN nodes depending on the RAT used in the RAN. A RAN node may be referred to as node B (NB) in a RAN using the UMTS RAT. A RAN node may be referred to as advanced node B (eNB) in a RAN using the LTE / EUTRA RAT. In the exemplary example of the mobile communication system 100 in Figure 1, the nodes of NG-RAN 105 may be either next-generation node B (gNB) 115 (e.g., gNB115A, gNB115B) or next-generation advanced node B (ng-eNB) 120 (e.g., ng-eNB120A, ng-eNB120B). In this specification, the terms base station, RAN node, gNB, and ng-eNB may be used interchangeably. The gNB115 can provide NR user plane and control plane protocol termination to the UE125. The ng-eNB120 can provide E-UTRA user plane and control plane protocol termination to the UE125. The interface between the gNB115 and the UE125 or between the ng-eNB120 and the UE125 may be referred to as a Uu interface. The Uu interface may be established with the user plane protocol stack and the control plane protocol stack. In the case of a Uu interface, the direction from the base station (e.g., gNB115 or ng-eNB120) to the UE125 may be referred to as a downlink, and the direction from the UE125 to the base station (e.g., gNB115 or ng-eNB120) may be referred to as an uplink.

[0020] The gNB115 and ng-eNB120 can be interconnected 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-Purpose Packet Radio Services (GPRS) Tunneling Protocol (GTP) may be used over User Datagram Protocol (UDP) / IP to carry User Plane Protocol Data Units (PDUs). Xn-U can provide unguaranteed delivery of User Plane PDUs and can support data transfer and flow control. The transport network layer of the Xn-C interface may be built on Stream Control Transport Protocol (SCTP) over IP. The application layer signaling protocol is XnAP (Xn Application It is sometimes referred to as the SCTP Protocol. The SCTP layer can provide guaranteed delivery of application layer messages. In the transport IP layer, point-to-point transmission may be used to deliver signaling PDUs. The Xn-C interface can support Xn interface management, UE mobility management including context forwarding and RAN paging, and dual connectivity.

[0021] The gNB115 and ng-eNB120 can also be connected to the 5GC110 using the NG interface, more specifically to the 5GC110's Access and Mobility Management Function (AMF) 130 (e.g., AMF130A, AMF130B) using the NG-C interface, and to the 5GC110's User Plane Function (UPF) 135 (e.g., UPF135A, UPF135B) using the 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 UDP / IP to transport user plane PDUs between the NG-RAN node (e.g., gNB115 or ng-eNB120) and the UPF 135. The NG-U can provide unguaranteed delivery of user plane PDUs between the NG-RAN node 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 is sometimes referred to as NGAP (NG Application Protocol). The SCTP layer can provide guaranteed delivery of application layer messages. In transport, IP layer point-to-point transmission may be used to deliver signaling PDUs. The NG-C interface can provide the following functions: NG interface management, UE context management, UE mobility management, NAS message transport, paging, PDU session management, configuration transfer, and alert message transmission.

[0022] The gNB115 or ng-eNB120 provides the following functions: wireless resource management functions such as wireless bearer control, wireless admission control, connectivity mobility control, dynamic allocation of resources to UEs on both uplink and downlink (e.g., scheduling), IP and Ethernet header compression, data encryption and integrity protection, AMF selection in the UE attachment when routing to the 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, connectivity setup and release, scheduling and transmission of paging messages (e.g., originating from the AMF). It can host one or more of the following: scheduling and transmission of system broadcast information; measurement and measurement reporting configuration for mobility and scheduling; transport level packet marking on uplinks; session management; support for network slicing; QoS flow management and mapping to data radio bearers; UE support in RRC inactive state; distribution function for NAS messages; radio access network sharing; dual connectivity; tight interworking between NR and E-UTRA; and security and radio configuration maintenance for user plane 5G systems (5GS) cellular IoT (CIoT) optimization.

[0023] The AMF130 offers one of the following features: NAS signaling termination, NAS signaling security, AS security control, CN node inter-signaling for mobility between 3GPP® access networks, idle mode UE reachability (including control and execution of paging retransmission), registered area management, support for intra-system and inter-system mobility, access authentication, access authorization including roaming right checks, mobility management control (subscriptions and policies), network slicing support, Session Management Function (SMF) selection, and 5GS CIoT optimization selection. It can host multiple devices.

[0024] The UPF135 can host one or more of the following functions: anchor points for intra-RAT / inter-RAT mobility (when applicable), external PDU session points for interconnection to data networks, user plane portions of packet routing and forwarding, packet inspection and policy rule enforcement, traffic usage reporting, uplink classifiers to support routing of traffic flows to data networks, branching points to support multi-homed PDU sessions, and QoS processing for the user plane, such as packet filtering, gating, UL / DL rate enforcement, uplink traffic validation (mapping service data flows (SDF) to QoS flows), downlink packet buffering, and downlink data notification triggering.

[0025] As shown in Figure 1, NG-RAN105 can support a PC5 interface between two UE125s (e.g., UE125A and UE125B). On the PC5 interface, the direction of communication between the two UEs (e.g., from UE125A to UE125B, or vice versa) is sometimes referred to as a sidelink. Sidelink transmission and reception via the PC5 interface may be supported when the UE125 is within the coverage of NG-RAN105, and when the UE125 is outside the coverage of NG-RAN105, regardless of the RRC state the UE is in. Support for V2X services via the PC5 interface may be provided by NR sidelink communication and / or V2X sidelink communication.

[0026] PC5-S signaling can be used to establish a unicast link using direct communication request / acceptance 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, the UE can send its source layer 2 ID for the PC5 unicast link to a peer UE, for example, the UE that received the destination ID from the upper layer. The pair of source layer 2 ID and destination layer 2 ID can uniquely identify the unicast link. The receiving UE can verify that the destination ID belongs to it and accept the unicast link establishment request from the source UE. During the PC5 unicast link establishment procedure, the PC5-RRC procedure on the access stratum may be called for UE sidelink context establishment, as well as for AS layer configuration, capability exchange, etc. PC5-RRC signaling can enable the exchange of UE capabilities and AS layer configurations, such as sidelink radio bearer configuration, between pairs of UEs on 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 layer 2IDs and destination layer 2IDs in an AS. Unicast transmission mode may be characterized by support for one PC5-RRC connection between peer UEs for the pair, transmission and reception of control information and user traffic between peer UEs in the sidelink, support for sidelink HARQ feedback, support for sidelink transmission power control, support for RLC response mode (AM), and detection of radio link failures for the PC5-RRC connection. Groupcast transmission may be characterized by transmission and reception of user traffic between UEs belonging to a group in the sidelink, and support for sidelink HARQ feedback. Broadcast transmission may be characterized by transmission and reception of user traffic between UEs in the sidelink.

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

[0029] Figures 2A and 2B show examples of radio protocol stacks for the user plane and control plane, respectively, according to some aspects of one or more exemplary embodiments of the present disclosure. As shown in Figure 2A, the protocol stack for the user plane of the Uu interface (between UE125 and gNB115) includes Service Data Adaptive Protocol (SDAP) 201 and SDAP211, Packet Data Convergence Protocol (PDCP) 202 and PDCP212, Radio Link Control (RLC) 203 and RLC213, MAC204 and MAC214 sublayers of Layer 2, and Physical (PHY) 205 and PHY215 layers (Layer 1 is also referred to as L1).

[0030] PHY205 and PHY215 provide transport channels 244 to MAC204 and MAC214 sublayers. MAC204 and MAC214 sublayers provide logical channels 243 to RLC203 and RLC213 sublayers. RLC203 and RLC213 sublayers provide RLC channels 242 to PDCP202 and PCP212 sublayers. PDCP202 and PDCP212 sublayers provide radio bearers 241 to SDAP201 and SDAP211 sublayers. 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. SDAP201 and SDAP211 sublayers provide QoS flows 240 to 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 to and from transport blocks (TBs) delivered to and from the physical layer on the transport channel, scheduling information reporting, error correction via Hybrid Automatic Retransmission Request (HARQ) (one HARQ entity per cell in the case of carrier aggregation (CA)), and dynamic scheduling. This includes prioritizing between UEs using UE-Ring, prioritizing between logical channels of a single UE using Logical Channel Prioritization (LCP), prioritizing between overlapping resources of a single UE, and padding. A single MAC entity can support multiple numerologies, transmission timings, and cells. Mapping restrictions in Logical Channel Prioritization control which of the numerologies (multiple), cells (multiple), and transmission timings (multiple) a logical channel can use.

[0032] The HARQ function can ensure delivery between peer entities at Layer 1. A single HARQ process can support one TB if the physical layer is not configured for downlink / uplink spatial multiplexing, and a single HARQ process can support one or more 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), non-response mode (UM), and response mode (AM). The RLC configuration may be per logical channel, independent of numerology and / or transmission duration, and automatic retransmission requests (ARQs) may operate on either the numerology and / or transmission duration in which the logical channel is configured.

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

[0035] An automatic retransmission request within the RLC203 or RLC213 sublayer may have the following characteristics: The ARQ retransmits the RLC SDU or RLC SDU segment based on the RLC status report. Polling for the RLC status report may be used when required by the 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 sublayer may include data (user plane or control plane) transfer, maintenance of PDCP sequence numbers (SNs), 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 discarding, routing for split bearers, replication, sorting and in-order delivery, out-of-order delivery, and replication discarding.

[0037] The primary services and functions of SDAP201 or SDAP211 include mapping QoS flows to data radio bearers and marking QoS flow IDs (QFIs) in both downlink and uplink packets. A single protocol entity of SDAP may be configured for each individual PDU session.

[0038] As shown in Figure 2B, the protocol stack of the control plane of the Uu interface (between UE125 and gNB115) includes the PHY layer (layer 1), the MAC sublayer, RLC sublayer, and PDCP sublayer of layer 2 as described above, and further, the RRC206 sublayer and RRC216 sublayer. The main services and functions of the RRC206 sublayer and RRC216 sublayer on the Uu interface are related to system information of the AS and NAS. This includes broadcast, paging initiated by 5GC or NG-RAN, establishment, maintenance, and release of RRC connectivity 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 forwarding, UE cell selection and reselection, and control of cell selection and reselection, and inter-RAT mobility), QoS management functions, UE measurement reporting and reporting control, radio link failure detection and recovery from radio link failure, and NAS message forwarding from NAS to UE / UE to NAS. The NAS207 and NAS227 layers are control protocols (terminated at the network-side AMF) that perform functions such as authentication, mobility management, and security control.

[0039] The RRC sublayer sidelink-specific services and functions on the Uu interface include configuring sidelink resource allocation via system information or dedicated signaling, reporting UE sidelink information, configuring and reporting sidelink-related measurements, and reporting UE-supported information for SL traffic patterns(s).

[0040] Figures 3A, 3B, and 3C show exemplary mappings between logical channels and transport channels in downlink, uplink, and sidelink, respectively, according to some aspects of one or more exemplary embodiments of the present disclosure. Different types of data transfer services may be provided by the MAC. Each logical channel type can be defined by the type of information being transferred. Logical channels can be classified into two groups: control channels and traffic channels. Control channels may be used for transferring control plane information only. A broadcast control channel (BCCH) is a downlink channel for broadcasting system control information. A paging control channel (PCCH) is a downlink channel for carrying paging messages. A 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 RRC connectivity to the network. A dedicated control channel (DCCH) is a point-to-point bidirectional channel for transmitting dedicated control information between the UE and the network and may be used by UEs with RRC connectivity. Traffic channels may be used for transferring 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. DTCHs can exist on both uplinks and downlinks. A sidelink control channel (SCCH) is a sidelink channel for transmitting control information (e.g., PC5-RRC messages and PC5-S messages) from one UE to another(s). A sidelink traffic channel (STCH) is a sidelink channel for transmitting user information from one UE to another(s). A sidelink broadcast control channel (SBCCH) is a sidelink channel for broadcasting sidelink system information from one UE to another(s).

[0041] Downlink transport channel types include broadcast channels (BCH), downlink shared channels (DL-SCH), and paging channels (PCH). BCH may be characterized by a fixed, predefined transport format and the requirement to be broadcast across the entire cell coverage area, either as a single message or by beamforming different BCH instances. DL-SCH may be characterized by support for HARQ, support for dynamic link adaptation by varying modulation, coding, and transmission power, the possibility of broadcasting across the entire cell, the possibility of using beamforming, support for both dynamic and semi-static resource allocation, and support for UE intermittent reception (DRX) to enable UE power saving. PCH may be characterized by support for dynamic link adaptation by varying the tuning, coding, and transmission power, the possibility of broadcasting across the entire cell, the possibility of using beamforming, support for both dynamic and semi-static resource allocation, and support for UE intermittent reception (DRX) to enable UE power saving. PCH may be characterized by support for UE intermittent reception (DRX) to enable UE power saving (DRX cycles are indicated to the UE by the network), and by mapping the requirement to be broadcast across the entire cell coverage area as a single message or by beamforming different BCH instances to physical resources that can also be dynamically used for traffic / other control channels.

[0042] In the downlink, the following connections may exist between the logical channel and the transport channel: 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 uplink shared channels (UL-SCH) and random access channels (RACH). UL-SCH may be characterized by the possibility of using beamforming, support for dynamic link adaptation by varying transmission power and potentially modulation and coding, support for HARQ, and support for both dynamic and semi-static resource allocation. RACH may be characterized by limited control information and collision risk.

[0044] In the uplink, the following connections may exist between the logical channel and the transport channel: 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 sidelink broadcast channels (SL-BCH) and sidelink shared channels (SL-SCH). SL-BCH may be characterized by a predefined transport format. SL-SCH may be characterized by support for unicast transmission, groupcast transmission, and broadcast transmission; support for both UE autonomous resource selection and scheduled resource allocation by NG-RAN; support for both dynamic and semi-static resource allocation when UEs are allocated resources by NG-RAN; support for HARQ; and support for dynamic link adaptation by varying transmission power, modulation, and coding.

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

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

[0048] Physical channels in an uplink include the physical uplink shared channel (PUSCH), the physical uplink control channel (PUCCH), and the physical random access channel (PRACH). UL-SCH transport channels may be mapped to PUSCH, and RACH transport channels may be mapped to PRACH. No transport channel is mapped to PUCCH; instead, uplink control information (UCI) is transmitted.

[0049] Physical channels in a sidelink include the Physical Sidelink Shared Channel (PSSCH), Physical Sidelink Control Channel (PSCCH), Physical Sidelink Feedback Channel (PSFCH), and Physical Sidelink Broadcast Channel (PSBCH). The Physical Sidelink Control Channel (PSCCH) may indicate resources and other transmission parameters used by the UE for the PSSCH. The Physical Sidelink Shared Channel (PSSCH) may transmit the TB of the data itself, as well as control information for HARQ procedures and Channel State Information (CSI) feedback triggers, etc. At least six orthogonal frequency division multiplexing (OFDM) symbols in a slot may be used for PSSCH transmission. The Physical Sidelink Feedback Channel (PSFCH) can carry HARQ feedback over the sidelink from the UE that is the intended receiver of the PSSCH transmission to the UE that performed the transmission. The PSFCH sequence may be transmitted within a single PRB 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. SL-BCH can be mapped to PSBCH. Transport channels are not mapped to PSFCH, but side-link feedback control information (SFCI) can be mapped to PSFCH. Transport channels are not mapped to PSCCH, but side-link control information (SCI) can be mapped to it.

[0050] Figures 5A, 5B, 5C, and 5D show 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 the STCH) in the PC5 interface may consist of SDAP, PDCP, RLC, and MAC sublayers, and a physical layer. The protocol stack for the user plane is shown in Figure 5A. The AS protocol stack for the SBCCH in the PC5 interface may consist of RRC, RLC, MAC sublayers, and a physical layer, as shown in Figure 5B below. For support of the PC5-S protocol, the PC5-S is located above the PDCP, RLC, and MAC sublayers, and the physical layer in the control plane protocol stack for the SCCH for PC5-S, as shown in Figure 5C. The AS protocol stack for the control plane for the SCCH for RRC in the PC5 interface consists of RRC, PDCP, RLC, and MAC sublayers, and a physical layer. The protocol stack for the control plane of the SCCH for RRC is shown in Figure 5D.

[0051] Sidelink radio bearers (SLRBs) can 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 via the PC5 interface: radio resource selection, packet filtering, priority processing between uplink and sidelink transmissions for a given UE, and sidelink CSI reporting. Due to limitations in logical channel prioritization in MAC, sidelinks belonging to the same destination may be subject to different prioritization. Only the source channel can be multiplexed into MAC PDUs for all unicast, groupcast, and broadcast transmissions that may be associated with the destination. For packet filtering, the SL-SCH includes both source layer 2ID and destination layer 2ID portions. A MAC header may be added to the MAC PDU. The logical channel identifier (LCID) contained within the MAC subheader can uniquely identify a logical channel within the range of combinations of source layer 2IDs and destination layer 2IDs.

[0053] RLC sublayer services and functions may be supported for sidelinks. Both RLC non-response mode (UM) and response mode (AM) may be used in unicast transmissions, but only UM may be used in groupcast or broadcast transmissions. In the case of UM, only unidirectional transmission may be supported for groupcast and broadcast.

[0054] The PDCP sub-layer services and functions for the Uu interface may be supported for sidelinks, but with some limitations, namely, out-of-order delivery may only be supported for unicast transmission, and replication may not be supported via the PC5 interface.

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

[0056] The RRC sublayer can provide the following services and functions via the PC5 interface: forwarding PC5-RRC messages between peer UEs, maintaining and releasing PC5-RRC connections between two UEs, and detecting sidelink radio link failures in PC5-RRC connections based on instructions from MAC or RLC. A PC5-RRC connection can be a logical connection between two UEs for a pair of source layer 2IDs and destination layer 2IDs, which can be considered established after the corresponding PC5 unicast link has been established. There can be a one-to-one correspondence between a PC5-RRC connection and a PC5 unicast link. A UE may have multiple PC5-RRC connections with one or more UEs for different pairs of source layer 2IDs and destination layer 2IDs. Separate PC5-RRC procedures and messages may be used by a UE to forward UE capabilities and sidelink configurations, including SL-DRB configurations, to a peer UE. Both peer UEs can exchange their own UE capabilities and sidelink configurations using separate bidirectional procedures in both sidelink directions.

[0057] Figure 6 shows exemplary physical signals in the downlink, uplink, and sidelink according to some aspects of one or more exemplary embodiments of the present disclosure. A demodulated reference signal (DM-RS) may be used in the downlink, uplink, and sidelink and may be used for channel estimation. The DM-RS is a UE-specific reference signal that can be transmitted with the physical channel in the downlink, uplink, or sidelink and may be used for channel estimation and coherent detection of the physical channel. A phase-tracking reference signal (PT-RS) may be used in the downlink, uplink, and sidelink and may be used to track the phase and mitigate performance loss due to phase noise. The PT-RS may be used primarily to estimate and minimize the impact of common phase error (CPE) on system performance. Due to its phase noise characteristics, the PT-RS signal may have low density in the frequency domain and high density in the time domain. The PT-RS may occur in combination with the DM-RS when the network is configured to have a PT-RS. A positioning reference signal (PRS) may be used in the downlink for positioning using different positioning techniques. The PRS uses a signal received from a base station to pair with a local replica in the receiver. It can be used to measure the delay of downlink transmission by causing interference. Channel status information reference signals (CSI-RS) can be used in downlink and sidelink. CSI-RS can be used, among other things, for channel status estimation, reference signal received power (RSRP) measurement for mobility and beam management, and time / frequency tracking for demodulation. CSI-RS can be configured UE-specific, but multiple users can share the same CSI-RS resource. The UE can determine the CSI report and transmit them to the base station in uplink using PUCCH or PUSCH. CSI reports can be carried in the sidelink MAC control element (CE). Primary synchronization signals (PSS) and secondary synchronization signals (SSS) can be used for radio frame synchronization. PSS and SSS can be used for cell discovery procedures during initial attachment or for mobility purposes. Sounding reference signals (SRS) can be used in uplink for uplink channel estimation. Similar to CSI-RS, SRS can act as a QCL reference for other physical channels so that they can be configured and transmitted in a pseudo-colocated manner with SRS. Sidelink PSS (S-PSS) and sidelink SSS (S-SSS) can be used in sidelinks for sidelink synchronization.

[0058] Figure 7 shows examples of radio resource control (RRC) states and transitions between different RRC states according to some aspects of one or more exemplary embodiments of the present disclosure. The UE can be in one of three RRC states: RRC connected state 710, RRC idle state 720, and RRC inactive state 730. After power-on, the UE may be in the RRC idle state 720, in which case the UE may use initial access and, via the RRC connection establishment procedure, establish a connection with the network, perform data transfers, 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 the RRC connection establishment / release procedure 740.

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

[0060] Figure 8 shows an exemplary frame structure and physical resources according to some aspects of one or more exemplary embodiments of the present disclosure. Downlink, uplink, or sidelink transmissions may be organized into frames with a duration of 10 ms, each consisting of 10 (0 to 9) 1 ms subframes. Each subframe may consist of k slots (k = 1, 2, 4, ...), where the number of slots k per subframe may depend on the subcarrier spacing of the carrier being transmitted. Slot durations may be 14 (0 to 13) symbols with a normally cyclic prefix (CP) and 12 symbols with an extended CP, and may scale in time as a function of the subcarrier spacing used, such that there are an integer number of slots in a subframe. Figure 8 shows a resource grid in the time and frequency domains. Each element of the resource grid, including 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, using non-slot-based scheduling, packet transmission may occur across a portion of a slot, for example, within two, four, or seven OFDM symbols, which may be referred to as minislots. Minislots may be used for low-latency application examples such as URLLC and for operation in unlicensed bandwidth. In some embodiments, minislots may also be used for fast, flexible scheduling of services (e.g., URLLC preemption via eMBB).

[0062] Figure 9 shows exemplary component carrier configurations in different carrier aggregation scenarios according to some aspects of one or more exemplary 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 continuous and discontinuous CCs in the same band or on different bands, as shown in Figure 9. gNBs and UEs may communicate using serving cells. A serving cell may be associated with at least one downlink CC (e.g., it may be associated with only one downlink CC, or it may be associated with both a downlink CC and an uplink CC). A 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) may be used to adjust the uplink frame timing relative to the downlink frame timing. The gNB can determine the desired timing advance setting and provide it to the UE. The UE may use the provided TA to determine its uplink transmission timing relative to the UE's observed downlink receive timing.

[0064] In an RRC-connected state, the gNB may be responsible for maintaining the timing advance to keep L1 synchronized. Serving cells that have uplinks to which the same timing advance applies and use the same timing reference cell are grouped into a timing advance group (TAG). A TAG may contain at least one serving cell with configured uplinks. The mapping of serving cells to a TAG may be configured by the RRC. In the case of a primary TAG, the UE may use a PCell as the timing reference cell, except for shared spectral channel access, where in some cases a SCell may also be used as the timing reference cell. In 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] Timing advance updates can be signaled to the UE by the gNB via a MAC CE command. Such a command may restart a TAG-specific timer that indicates whether L1 can be synchronized or not. When the timer is running, L1 can be considered synchronized; otherwise, L1 can be considered asynchronous (in which case uplink transmission can only occur over 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 within one TAG) that share 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 within multiple TAGs) that have different timing advances. NG-RAN can ensure that each TAG contains at least one serving cell. Non-CA A compatible UE may receive on a single CC and transmit on a single CC corresponding to only one serving cell (one serving cell in one TAG).

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

[0068] In a dual-connection scenario, the UE may consist of multiple cells, including a master cell group (MCG) for communication with the master base station, a secondary cell group (SCG) for communication with secondary base stations, and two MAC entities: 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 stations.

[0069] Figure 10 shows exemplary bandwidth portion configurations and switching according to some aspects of one or more exemplary embodiments of the present disclosure. A UE may consist of 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 can define the operating bandwidth of the UE within the operating bandwidth of the cell. For initial access and until the configuration of the UE in the cell is received, an initial bandwidth portion 1020 determined from system information may be used. Using bandwidth adaptation (BA), for example, through BWP switching 1040, the receive and transmit bandwidth of the UE may be adjusted, and may not be as large as the cell bandwidth. For example, the width may be commanded to vary (e.g., to reduce during periods of low activity to conserve power), the position 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 BWP1030 may be the active BWP during RRC(re)configuration for PCell or activation of SCell.

[0070] For each downlink BWP or uplink BWP in a set of downlink BWPs, the UE may be provided with the following configuration parameters: subcarrier spacing (SCS), cyclic prefix, common RB and multiple neighboring RBs, an index in the set of downlink BWPs or uplink BWPs by each BWP-Id, a set of BWP common parameters, and a set of BWP-specific parameters. A BWP may be associated with OFDM numerology according to the configured subcarrier spacing and cyclic prefix for the BWP. In the case of a serving cell, the UE may be provided by the 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 can be associated with a BWP inactivity timer. If the BWP inactivity timer associated with an active downlink BWP expires and a default downlink BWP is configured, the UE can perform a BWP switch to the default BWP. If not, the UE can perform a BWP switch to the initial downlink BWP.

[0072] Figure 11 shows an exemplary four-step competition-based random access (CBRA) process and a non-compete random access (CFRA) process according to some aspects of one or more exemplary embodiments of the present disclosure. Figure 12 shows an exemplary two-step competition-based random access (CBRA) process and a non-compete random access (CFRA) process according to some aspects of one or more exemplary embodiments of the present disclosure. A random access procedure may be triggered by a number of events, e.g., initial access from an RRC idle state, an RRC connection re-establishment procedure, downlink or uplink data arrival in an RRC connection state when the uplink synchronization status is "asynchronous", uplink data arrival in an RRC connection state when there are no available PUCCH resources for a scheduling request (SR), SR failure, a request by the RRC during synchronous 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 fault recovery (BFR), or a consistent uplink listen before talk (LBT) failure on the PCell.

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

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

[0075] A 4-step RA type MSG1 may consist of a preamble on PRACH (step 1 of CBRA in Figure 11). After MSG1 transmission, the UE can monitor for responses from the network within a configured window (step 2 of CBRA in Figure 11). In the case of CFRA, a dedicated preamble for MSG1 transmission may be allocated by the network (step 0 of CFRA in Figure 11), and upon receiving a Random Access Response (RAR) from the network, the UE may terminate the random access procedure as shown in Figure 11 (steps 1 and 2 of CFRA in Figure 11). In the case of CBRA, upon receiving a Random Access Response (step 2 of CBRA in Figure 11), the UE transmits MSG3 using the scheduled uplink authorization in the Random Access Response (step 3 of CBRA in Figure 11) and can monitor for conflict resolution as shown in Figure 11 (step 4 of CBRA in Figure 11). If conflict resolution is unsuccessful after MSG3(re)transmission(s), the UE can return to MSG1 transmission.

[0076] A two-step RA type MSGA can include a preamble on PRACH and a payload on PUSCH (e.g., step A of CBRA in Figure 12). After the MSGA transmission, the UE can monitor responses from the network within a configured window. With respect to CFRA, dedicated preamble and PUSCH resources may be configured for MSGA transmission (steps 0 and A of CFRA in Figure 12), and upon receiving a network response (step B of CFRA in Figure 12), the UE can, as shown in Figure 12, The random access procedure can be terminated. In the case of CBRA, if conflict resolution is successful when a network response is received (step B of CBRA in Figure 12), the UE can terminate the random access procedure as shown in Figure 12. On the other hand, if a fallback instruction is received in MSGB, the UE can perform an MSG3 transmission using the uplink grant scheduled in the fallback instruction and monitor the conflict resolution. If conflict resolution is unsuccessful after MSG3(re)transmission(s), the UE can return to MSGA transmission.

[0077] Figure 13 shows 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. An 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 Figure 13), and a PBCH on one symbol spanning three OFDM symbols and 240 subcarriers, but leaving an unused portion in the center for the SSS as shown in Figure 13. The possible time positions of an SSB within a half-frame may be determined by the subcarrier spacing, and the periodicity of the half-frame in which the SSB is transmitted may be configured by the network. Within a half-frame, different SSBs may be transmitted in different spatial directions (i.e., using different beams extending over the cell's coverage area).

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

[0079] Figure 14 shows an exemplary SSB burst transmission according to some aspects of one or more exemplary embodiments of the present disclosure. An SSB burst may include N SSBs (e.g., SSB_1, SSB_2, ..., SSB_N), where each of the N SSBs may correspond to a beam (e.g., beam_1, beam_2, ..., beam_N). An SSB burst may be transmitted according to a periodicity (e.g., SSB burst duration). During a competition-based random access process, a UE may perform a random access resource selection process, in which the UE first selects an SSB before selecting an RA preamble. The UE may select an SSB having an RSRP above a configured threshold. In some embodiments, the UE may select any SSB if no SSB with an RSRP above a configured threshold is available. A set of random access preambles may be associated with an SSB. After selecting an SSB, the UE may select a random access preamble from the set of random access preambles associated with the SSB and transmit the selected random access preamble to initiate the random access process.

[0080] In some embodiments, one 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 can measure the CSI-RS resources and select a CSI-RS having an RSRP above a configured threshold. The UE can select a random access preamble corresponding to the selected CSI-RS and 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 can select a random access preamble corresponding to a quasi-colocated SSB with the selected CSI-RS.

[0081] In some embodiments, based on UE measurements of CSI-RS resources and UE CSI reports, the base station may determine a Transmission Configuration Indication (TCI) state and indicate the TCI state to the UE, which can then use the indicated TCI state to receive downlink control information (e.g., via PDCCH) or data (e.g., via PDSCH). The UE can use the indicated TCI state to use the appropriate beam for receiving data or control information. The indication of a TCI state may use an RRC configuration or a combination of RRC signaling and dynamic signaling (e.g., via MAC control elements (MAC CE) and / or based on the value of a field in the downlink control information that schedules downlink transmissions). The TCI state may indicate a quasi-collocation (QCL) relationship between a downlink reference signal, such as 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 consist of a list of up to M TCI state configurations, using physical downlink shared channel (PDSCH) configuration parameters, to decode the PDSCH according to a detected PDCCH having a DCI for the UE and a given serving cell, where M may depend on the UE capability. Each TCI-State may include one or two downlink reference signals and parameters for configuring a QCL relationship between the DM-RS port of the PDSCH, the DM-RS port of the PDCCH, or the CSI-RS port(s) of a CSI-RS resource. The quasi-collocation relationship may consist of 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, mean delay, delay spread}, "QCL-TypeB": {Doppler shift, Doppler spread}, "QCL-TypeC": {Doppler shift, mean delay}, "QCL-TypeD": {Spatial Rx parameter}. The UE may receive activation commands (e.g., MAC CE) used to map TCI states to code points in the DCI fields.

[0083] Figure 15 shows exemplary components of a user terminal and a base station for transmission and / or reception, according to some aspects of one or more exemplary embodiments of the present disclosure. In one embodiment, the exemplary components of Figure 15 can be considered exemplary functional blocks of an exemplary base station 1505. In another embodiment, the exemplary components of Figure 15 can be considered exemplary functional blocks of an exemplary user terminal (UE) 1500. Thus, the components shown in Figure 15 are not necessarily limited to either a UE or a base station.

[0084] Referring to Figure 15, the antenna 1510 may be used for transmitting or receiving electromagnetic signals. The antenna 1510 may include one or more antenna elements and may be configured in multiple-input multiple-output (MIMO), multiple-input single-output (MISO), and single-input multiple-output (SIMO) configurations. This may enable different input / output antenna configurations, including those mentioned above. In some embodiments, antenna 1510 may enable large-scale MIMO configurations with tens or hundreds of antenna elements. Antenna 1510 may enable other multi-antenna techniques such as beamforming. In some examples, depending on the capabilities of UE1500 or the type of UE1500 (e.g., low-complexity UE), UE1500 may support only a single antenna.

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

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

[0087] The processor 1540 may include hardware devices with processing capabilities (e.g., general-purpose processors, digital signal processors (DSPs), central processing units (CPUs), microcontrollers, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), programmable logic devices, discrete gate or transistor logic components, discrete hardware components, or any combination thereof). In some examples, the processor 1540 may be configured to operate memory using a memory controller. In other examples, the memory controller may be integrated into the processor 1540. The processor 1540 may be configured to execute computer-readable instructions stored in memory (e.g., memory 1530) to cause the UE 1500 or base station 1505 to perform various functions.

[0088] The CPU 1550 can perform basic arithmetic, logical, control, and input / output (I / O) operations specified by computer instructions in 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 operation and modification of memory 1530 to accelerate the 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 geographical location of the UE 1500.

[0089] In some examples, the UE1500 (device) may be configured or programmed for the transmission of channel status information (CSI) reports in a mobile communications network. The UE1500 may include a memory (e.g., memory 1530 in Figure 15) for storing instructions (e.g., code 1535 in Figure 15) and a processor (e.g., processor 1540 in Figure 15) configured to execute 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 parameters, measures one or more second reference signals based on the second CSI configuration parameters, transmits a first CSI report associated with one or more MBS based on the measurement of the first reference signals, and transmits one or more unicast service reports based on the measurement of the second reference signals. It is further configured to execute instructions for transmitting a second CSI report associated with the service. In these examples, the memory of the UE1500 (e.g., memory 1530) may store computer program code (e.g., code 1535) that can be executed by the processor (e.g., CPU 1550) to perform the functions of the UE1500.

[0090] In some examples, base station 1505 may be configured or programmed for CSI report transmission in a mobile communications network. Base station 1505 may include a memory (e.g., memory 1530 in Figure 15) for storing instructions (e.g., code 1535 in Figure 15) and a processor (e.g., processor 1540 in Figure 15) configured to execute instructions for transmitting 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 one or more second reference signals based on the second CSI configuration parameter. The processor may be configured to execute instructions for transmitting downlink control information indicating a request for transmission of at least one of the first or second CSI reports. Downlink control information may trigger the UE to generate and / or transmit at least one of a first CSI report or a second CSI report. In these examples, the memory of the base station 1505 (e.g., memory 1530) may store computer program code (e.g., code 1535) that can be executed by a processor (e.g., CPU 1550) to perform the functions of the base station 1505.

[0091] In some examples, the UE1500 and base station 1505 are included in a system for mobile communications. 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 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., MCCHs) and one or more multicast / broadcast data channels (e.g., MTCHs) may be mapped onto a DL-SCH. Scheduling may be performed by a 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 service identifiers, such as temporary mobile group identifiers (TMGIs), and RAN level identifiers, such as group identifiers (G-RNTIs), may be used for receiving DL-SCHs to which multicast / broadcast data channels may be mapped. In some examples, a single transmission may be used for DL-SCHs associated with multicast / broadcast control channel and / or multicast / broadcast data channel transmissions, HARQ or RLC retransmission may not be used, and / or RLC non-response mode (RLC UM) may be used. In other examples, some form of feedback (e.g., HARQ feedback or RLC feedback) may be used for transmission over multicast / broadcast control channels and / or multicast / broadcast data channels.

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

[0094] In some cases, one or more UE identifiers may be related to MBS transmission. One or more identifiers may include at least one of one or more first RNTIs that identify multicast / broadcast control channel transmissions and one or more second RNTIs that identify multicast / broadcast data channel transmissions. One or more first RNTIs that identify multicast / broadcast control channel transmissions may include single-cell RNTIs (SC-RNTIs, other names may be used). One or more second RNTIs that identify multicast / broadcast data channel transmissions may include G-RNTIs (nG-RNTIs, other names may be used).

[0095] In some cases, one or more logical channels may be involved in MBS transmission. One or more logical channels may include a multicast / broadcast control channel. A 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 a UE that receives or is interested in receiving MBS. 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 cases, a procedure may be used by the UE to notify the RAN that the UE is receiving or interested in receiving MBS services(s) via an MBS radio bearer, and if so, to notify the 5G RAN of the priority for receiving MBS services(s) in MBS-versus-unicast or receive-only mode. An example is shown in Figure 16. The UE may transmit a message (e.g., an MBS interest indication message) to notify the RAN that the UE is receiving / interested in receiving MBS services(s), or no longer receiving / not interested in receiving MBS services(s). The UE may transmit a message based, for example, on receiving one or more messages (e.g., an SIB message or a unicast RRC message) from the network indicating one or more MBS service area identifiers for the current and / or adjacent carrier frequencies.

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

[0098] In some cases, control information for receiving MBS services may be provided on a specific logical channel (e.g., MCCH). The MCCH provides information about ongoing MBS sessions, as well as (corresponding) information about when each session may be scheduled, e.g., schedule One or more configuration messages may be carried, indicating the ringing period, scheduling window, and start offset. One or more configuration messages may provide information about neighboring cells that may be 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 cases, MCCH information (e.g., information transmitted in messages sent via MCCH) may be transmitted periodically using a configurable repetition period. MCCH transmissions (and associated radio resources and MCS) may be shown on PDCCH.

[0100] In some cases, changes to MCCH information may occur in a specific radio frame / subframe / slot, and / or a change period may be used. For example, within a change period, the same MCCH information may be transmitted multiple times, as defined by its scheduling (based on an iteration period). A change period boundary may be defined by an SFN value where SFN mod m = 0, where m is the number of radio frames containing the change period. The change period may be constructed by SIB or by RRC signaling.

[0101] In some cases, when the network modifies some of the MCCH information, it may notify the UE of the changes in a first subframe / slot that can be used for MCCH transmission during the iteration period. Upon receiving the change notification, a UE interested in receiving MBS services may obtain the new MCCH information starting from the same subframe / slot. The UE can apply the previously obtained MCCH information until it obtains the new MCCH information.

[0102] For example, a System Information Block (SIB) may include information necessary to obtain control information associated with MBS transmissions. This information may include at least one of the following: one or more intermittent reception (DRX) parameters for monitoring scheduling information for MBS control information-related transmissions; scheduling period and offset for scheduling information for MBS control information-related transmissions; change period for changes in the content of MBS control information-related transmissions; and repetition information for repetition of MBS control information-related transmissions.

[0103] For example, an information element (IE) may provide configuration parameters indicating, for instance, a list of ongoing MBS sessions transmitted through 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 the following: one or more timer values ​​for intermittent reception (DRX) (e.g., inactivity timer or on-duration timer), RNTIs for scheduling and scrambling transmission of multicast / broadcast traffic channels (e.g., MTCH, other names may be used), 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, and information about a list of neighbor cells.

[0104] Exemplary embodiments may enable RAN functionality for broadcast / multicast for UEs in the 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 able to operate concurrently with unicast reception. In some examples, broadcast / multicast service delivery may be multicast (PTM) and unicast with service continuity for a given UE. It can be dynamically changed to and from Nicast (PTP). In some examples, coordination functions may reside within the gNB-CU. In some examples, the reliability of broadcast / multicast services can 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 can be dynamically controlled within a single gNB-DU.

[0105] In some examples, multicast and broadcast service (MBS) services may be provided using point-to-multipoint (PTM), for example, a single-cell point-to-multipoint (SC-PTM) framework. The SC-PTM framework may also be used for one or more of the following: 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 through one or more cells. In some examples, data for MBS services may be transmitted over the PDSCH using a first RNTI, for example, a group-specific radio network ephemeral identifier (e.g., G-RNTI), and control information associated with the MBS service may be transmitted over the PDSCH using a second RNTI, for example, a single-cell point-to-multipoint radio network ephemeral identifier (e.g., SC-RNTI).

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

[0107] In some cases, the UE can first discover and subscribe to MBS services through application layer signaling or other means, such as pre-provisioning on the device. Such service discovery signaling / provisioning provides the UE with certain service identifiers for the subscribed MBS services. This may be provided to E. In some cases, the service identifier may be a temporary mobile group identifier (TMGI).

[0108] In some examples, when a UE in the RRC_CONNECTED state receives a PDSCH carrying MBS data, the UE may provide feedback in the form of Uplink Control Information (UCI) indicating successful reception of the PDSCH or a NACK indicating unsuccessful reception of the PDSCH. The UE can determine the PUCCH resource set by the size of the UCI information. In some examples, the UE may determine the PUCCH resource from the resource set by using the 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 feedback on each UE's PUCCH resource, 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, a UE may provide NACK feedback if it fails to successfully receive the corresponding MBS PDSCH; otherwise, it may not provide feedback. In some examples, a gNB may configure a PUCCH resource that carries only NACKs. In some examples, a gNB may perform multicast-based retransmission when it receives at least one NACK feedback on the NACK resource, for example, based on energy detection.

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

[0111] In some cases, UE-specific ACK / NACK mechanisms may be used. A UE can send an ACK if the packet was received correctly, and a NACK if it was received incorrectly. Each UE has separate resources for transmitting ACKs / NACKs.

[0112] In some cases, 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 resources to transmit the NACK.

[0113] In some cases, autonomous / blind retransmission with or without feedback may be used for aggregated PDSCHs. 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 cases, multicast retransmission based on group NACKs 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 cases, retransmission may be multicast or unicast based on UE-specific ACK / NACK feedback. The transmitter may retransmit the data by using a 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 cases, CSI (e.g., CQI, PMI, RI, RSRP / RSRQ, SINR, SRI, CRI, interference state) feedback can improve performance through adaptive link adaptation in changing communication environments or to assist in the management / operation of UE grouping.

[0117] In some cases, a UE receiving a PTM transmission may have its own UL resource for sending the corresponding HARQ feedback. In some cases, a PUCCH resource for PTM HARQ feedback may be dedicated to PTM HARQ feedback.

[0118] In some cases, PUCCH resources can be shared through PTM HARQ feedback and PTP HARQ feedback.

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

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

[0121] In some cases, CSI feedback (e.g., CQI / PMI / RI) can be used to improve PTM transmission reliability with greater resource efficiency. CSI feedback allows the gNB to know the general direction of the UE and what the correct MCS should be used. In some cases, a PTM-specific CSI-RS with a different scrambling ID compared to the PTP CSI-RS may be configured, allowing the UE to measure and report PTM-specific channel relation information. In some cases, a UE within a PTM group may consist of one or more CSI-RSs for the PTM and corresponding CSI reporting configurations.

[0122] In some cases, UE feedback, such as acknowledgments or denials (e.g., HARQ acknowledgments / denials or higher-layer acknowledgments / denials (such as RLC and / or PDCP)), can improve the reliability of receiving multicast and broadcast service (MBS) services.

[0123] In some cases, MBS services may be provided using point-to-multipoint (PTM) transmission within a cell. The cell's physical downlink shared channel (PDSCH) may be used by the base station to transmit multicast / broadcast data and control information to a group of UEs. For example, MBS service data may be transmitted via the PDSCH using a first RNTI (e.g., a group-specific radio network temporary identifier (G-RNTI)), and control information may be transmitted via the PDSCH using a second RNTI (e.g., a single-cell point-to-multipoint (SC-PTM) radio network temporary identifier (SC-RNTI)). In some cases, the reliability of MBS services 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, the Internet of Things (IoT), and vehicle-to-everything (V2X). Some MBS use cases may involve the transmission of periodic or aperiodic traffic with low to high data rates targeting several to thousands of UEs within a cell. In some examples, reliability requirements may vary depending on the MBS use case and / or deployment scenario (e.g., for HARQ-based retransmission or CSI feedback). The UE feedback mechanism may vary depending on the MBS use case and / or deployment scenario.

[0125] In some cases, retransmission may occur at the PDCP and / or RLC sublayers. RLC and / or PDCP retransmission may be sufficient for some use cases, and PHY / MAC-based retransmission (e.g., HARQ-based retransmission) may not be required. In some cases, RLC and / or PDCP retransmission may not meet the latency and efficiency requirements for some MBS use cases. In some cases, it may be necessary to support HARQ for MBS transmission. In some cases, the UE may report CSI feedback to improve the efficiency and reliability of MBS transmission. In some cases, the UE and base station may support HARQ for MBS transmission over 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] Figure 18 shows an exemplary retransmission mechanism involving retransmission in PDCP / RLC or MAC / PHY (e.g., HARQ-based retransmission). In the exemplary retransmission mechanism, the UE can support blind retransmission of MTCH data using resources scheduled / configured based on MCCH. The UE may not transmit HARQ feedback and may use a small number of retransmissions that may be configured based on higher-layer retransmission, e.g., PDCP or RLC retransmission. In the exemplary retransmission mechanism, the UE can support synchronous HARQ retransmission based on UE feedback. Resources for retransmission may be predetermined / preconfigured at the time of the initial transmission, and resources for retransmission may be used based on UE feedback if necessary. In some examples, synchronous HARQ retransmission may be used by a UE in an RRC connected state. In some examples, synchronous HARQ retransmission may be used by a UE in an RRC connected state, inactive state, or idle state, and power efficiency can be improved because resources used by possible retransmissions are preconfigured and can be used by the UE without having to monitor extra PDCCHs to find scheduling resources for retransmission. In an exemplary retransmission mechanism, an asynchronous HARQ with incremental redundancy (IR) may be used, where retransmissions can be dynamically scheduled using downlink control information (e.g., unicast). This process may be more spectrally efficient. A UE that has not received the previous transmission may monitor the PDCCH until it receives the retransmitted packet. In some examples, a UE may use one or more of the retransmission mechanisms described above.

[0127] In some cases, if a RAN receives a negative acknowledgment (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 cases, using synchronous HARQ retransmission, UEs may identify already received MBS transport blocks and avoid retransmission.

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

[0129] In some cases, various MBS services may be available for the UE. Some of the MBS services may include long-distance transmission of periodic traffic. In some cases, MBS services may be delivered to all UEs in the RRC state. In some cases, UEs in the RRC idle / inactive state may trigger data retransmission if necessary. These feedbacks can be transmitted to the network. UEs in an RRC idle and inactive state can receive MBS data and, if configured, provide feedback to the network.

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

[0131] In some examples, HARQ feedback from UEs while RRC idle / inactive may be supported. In one example, an RRC idle or inactive UE may return to the RRC connection to send their negative feedback regarding MBS data reception. In one example, an RRC idle or inactive UE may send HARQ feedback without retuning to the RRC connection state (e.g., options (ii), (iii), and (iv) in Figure 19). In some examples, for MBS HARQ, the RAN may configure an RRC idle or inactive UE to send HARQ feedback without retuning to the RRC connection state. For example, for an RRC idle and inactive UE, the UE may use PRACH to carry a HARQ NACK to the RAN, and the PRACH resource may be reserved to allow conflict-free access. In some examples, some common PUCCH resources may be configured to be used by such UE to send their feedback. In some examples, an RRC idle or inactive UE may use conflict-free RACH to send a HARQ NACK for a given MBS service. A NACK for one or more MBS services may be transmitted via a payload in a selected or specified message, depending on the specific RACH implementation. For example, according to a two-step RACH implementation, the NACK may be included as a payload in message A. In another example, according to a four-step RACH implementation, the NACK may be included as a 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 an MBS service by transmitting a PRACH along with the corresponding preamble.In some examples, idle or inactive UEs may be configured to use a common PUCCH resource to send NACK feedback, and connected UEs may reuse and share their PUCCHs for a unicast service to send their MBS feedback.

[0132] In some cases, 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 cases, HARQ feedback transmission from UEs for the MBS may be limited to NACK transmission based on the network / RRC configuration. For example, UEs may choose to limit HARQ feedback to NACK only. Configuration parameters may be received indicating whether the data can be transmitted for one purpose or for both ACK and NACK.

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

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

[0135] In some cases, the network may indicate a CSI-RS resource for the UE to measure MBS data, and the configured CSI-RS resource may differ from one used for unicast; for example, MBS data may not be beamformed or may have a wider beam than unicast data transmitted to different UEs within an MBS group. In the absence of such configuration or quasi-collocation (QCL) information, the UE may assume that MSB data is transmitted collated with SSB.

[0136] In some cases, the RAN may indicate a CSI-RS resource / port for the UE to measure for CSI feedback. Such instructions may be sent as a unicast RRC message to the UE instructed to send CSI feedback, or they may be included in a common MBS configuration available to all UEs.

[0137] In some cases, UEs may send their CSI feedback based on MBS data when they are in an RRC connection state.

[0138] In some cases, 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 cases, MBS CSI feedback may be based on DCI-triggered aperiodic CSI feedback.

[0139] In some examples, the network may instruct UEs to send their CSI feedback using a common set of PUCCH resources or based on message 3 / A of a 4 / 2 step RACH using one of the specified PRACH resources. In some examples, a subset of UEs to send CSI feedback may be selected randomly using a randomized seed and / or based on their received signals from base stations. In some examples, the RAN may decide to modify transmission parameters based on the CSI feedback. CSI feedback may be spread across time windows, so different UEs may send their feedback at different times, and a randomized seed may be used.

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

[0141] A UE can measure a reference signal based on its configuration parameters (for example, by measuring the radio resources indicated by the reference signal). The reference signal may be used by the UE to determine whether or not to transmit HARQ feedback. For example, the reference signal may be used by the UE to determine whether or not to transmit HARQ feedback for a received transport block associated with a service type (e.g., multicast and broadcast service (MBS) service type). The UE may measure a reference signal and determine the received power level associated with the reference signal (e.g., the 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 / greater than a threshold. Based on the reference signal measurement, the UE may determine that the reference signal received power is above / greater than a threshold. In some exemplary cases, the threshold may have a predetermined value. In some examples, the UE may receive one or more configuration parameters indicating 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., SIB) containing one or more configuration parameters indicating the threshold. In one example, the UE may be in an RRC connected state. The UE may receive an RRC message containing one or more configuration parameters indicating the threshold.

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

[0143] The UE can determine whether the received downlink MBS transport block was successfully received. The UE can determine whether to transmit the HARQ feedback associated with the downlink MBS transport block based on a comparison of the reference signal received power with a threshold. For example, based on the reference signal received power being greater than the threshold, the UE may decide to transition the HARQ feedback associated with the received downlink MBS transport block. For example, the UE may decide to transition the HARQ feedback associated with the received downlink MBS transport block based on the reference signal received power being greater than the threshold AND the HARQ feedback being a negative response. For example, the UE may transmit the HARQ feedback only if the reference signal received power is greater than the threshold and the HARQ feedback is a NACK. The UE may transmit the 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 cases, based on the transmission of HARQ feedback, the UE may receive a retransmission of the downlink MBS transport block.

[0144] In an exemplary embodiment as shown in Figure 21, the UE may be in a specified state, such as an RRC inactive state or an RRC idle state. The UE may receive an MBS transport block while in an RRC inactive state or an RRC idle state. For example, U E may receive a 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)). UE can determine whether the downlink MBS transport block has been received correctly (e.g., using a decoding process and / or based on error detection using a cyclic redundancy check (CRC) code). UE may decide to transmit HARQ feedback for the MBS transport block. For example, UE may decide to transmit HARQ feedback based on the fact that the HARQ feedback is a negative response. For example, UE may decide to transmit HARQ feedback based on the fact that the HARQ feedback is a negative response and based on comparing the received power level of a reference signal to a threshold. Based on the decision to transmit HARQ feedback for a transport block and based on the fact that UE is in an RRC idle or RRC inactive state, UE may transmit HARQ feedback or an instruction for HARQ feedback using a random access process (e.g., a two-step random access process or a four-step random access process). For example, one or more messages in a random access process may be used to transmit HARQ feedback or instructions for HARQ feedback.

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

[0146] In some cases, the UE may remain in an RRC inactive or RRC idle state (e.g., the RRC state of the UE before the HARQ feedback instruction via the random access process) after or before the completion of the random access process and after the transmission of HARQ feedback or HARQ feedback instructions.

[0147] In some examples, the UE may transition from an RRC inactive or RRC idle state (e.g., the UE's RRC state before instruction for HARQ feedback via the random access process) to an RRC connected state based on the random access process (e.g., after the 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 the uplink control channel. For example, the UE may receive configuration parameters for the uplink control channel via message 4 (in a 4-step random access process) or message B (in a 2-step random access process).

[0148] In some cases, a 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 negation response (NACK), and one or more second random access preambles may be configured / preconfigured as an acknowledgment (ACK). The base station may determine the HARQ feedback for the UE based on the random access preambles used in the random access process. For example, the UE may receive configuration parameters indicating which preambles are used for ACK or NACK indications 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 a NACK and / or that one or more second random access preambles may be used to indicate an ACK.

[0149] In some examples, a random access preamble used for a random access process may indicate that the initiation of the random access process may provide HARQ feedback.

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

[0151] In some examples, the instruction for 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 exemplary embodiments such as those shown in Figure 22, based on a 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 transmit instructions for HARQ feedback using an uplink control channel. The UE may transmit HARQ feedback or transmit instructions for HARQ feedback using an uplink control channel while remaining in an RRC idle or RRC inactive state. An uplink control channel may be configured in common 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 the radio resources of the uplink control channel.

[0153] In an exemplary embodiment as shown in Figure 23, the UE may receive a logical control channel (e.g., a multicast control channel (MCCH)) associated with the MBS service. The UE may receive the logical control channel via 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 receiving the downlink data channel used for transmitting 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 report may be associated with the MBS service and may be used by the base station for scheduling and transmission of MBS data. The UE may measure one or more reference signals based on CSI configuration parameters indicated by CSI configuration parameters (e.g., carried by MCCH). The UE may transmit a CSI report based on the CSI measurement and based on the CSI configuration parameters (e.g., carried by MCCH). In one example, the UE may transmit a CSI report based on a DCI indicating a request / trigger for the transmission of a CSI report (e.g., a periodic CSI report), or based on a radio resource for a periodic CSI report (e.g., configured by the CSI configuration parameters).

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

[0155] In one embodiment, a user terminal (UE) can determine that the received power level of a reference signal is greater than a threshold. The UE may receive a multicast broadcast service (MBS) transport block from the base station via the downlink data channel. Based on the fact that the received power level of the reference signal is greater than the threshold, the UE may transmit HARQ feedback associated with the MBS transport block to the base station.

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

[0157] In some embodiments, transmitting HARQ feedback associated with a transport block may be based further on the fact that the HARQ feedback is a negative response.

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

[0159] In some embodiments, the user terminal (UE) may be in one of the following states: Radio Resource Control (RRC) inactive state or RRC idle state.

[0160] In some embodiments, the UE can receive configuration parameters indicating the radio resources of a reference signal. The UE can use the configuration parameters to measure the reference signal. In some embodiments, the reception of the configuration parameters 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 configuration parameters indicating thresholds. In some embodiments, receiving configuration parameters may be via one of the following: a broadcast message and a radio resource control (RRC) dedicated message. Loadcast messages can be System Information Block (SIB) messages.

[0162] In one embodiment, a user terminal (UE) may receive a multicast broadcast service (MBS) transport block while the Radio Resource Control (RRC) is inactive or idle. The UE may decide to transmit HARQ feedback for the received MBS transport block. Based on this decision, and based on the fact that the UE is in an RRC inactive or idle state, the UE may transmit the HARQ feedback instruction using a random access process.

[0163] In some embodiments, the UE can transition from an RRC inactive or RRC idle state to an RRC connected state using a random access process. After transitioning to the RRC connected state, the UE can transmit HARQ feedback to the MBS transport block. 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 contain HARQ feedback. In some embodiments, the user terminal (UE) may remain in a radio resource control (RRC) inactive or RRC idle state after transmitting the random access preamble.

[0165] In some embodiments, the UE may receive configuration parameters indicating that one or more first random access preambles are for negative responses. In some embodiments, the UE may receive configuration parameters indicating that one or more second random access preambles are for positive responses. In some embodiments, the UE may receive a broadcast message containing configuration parameters. 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. Transmission of HARQ feedback instructions 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. Transmission of HARQ feedback instructions may be based on message 3 of the random access process.

[0168] In some embodiments, the user terminal (UE) may remain in a Radio Resource Control (RRC) inactive or RRC idle state after the transmission of HARQ feedback instructions.

[0169] In some embodiments, the random access process may include transmitting a random access preamble indicating that the random access process is intended to provide HARQ feedback.

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

[0171] In some embodiments, the decision to transmit HARQ feedback for a received MBS transport block may be based on the fact that the HARQ feedback is a negative response.

[0172] In one embodiment, a UE in a Radio Resource Control (RRC) inactive or RRC idle state may receive a Multicast Broadcast Service (MBS) transport block. The UE may decide to transmit HARQ feedback for the received MBS transport block. Based on this decision, and based on the UE being in an RRC inactive or RRC idle state, the UE may transmit instructions for HARQ feedback using an uplink control channel, which may be a common uplink control channel for multiple UEs in an RRC inactive or RRC idle state.

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

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

[0175] In some embodiments, the decision to transmit HARQ feedback for a received MBS transport block may be based on the fact that the HARQ feedback is a negative response.

[0176] In some embodiments, HARQ feedback instructions may be transmitted while the RRC remains in an inactive or idle state.

[0177] In one embodiment, the UE may receive a logical control channel associated with a multicast broadcast service (MBS) service via a downlink data channel, the logical control channel may carry control information including CSI configuration parameters for CSI measurement and CSI reporting, and the CSI report 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 measurement 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 receiving the MCCH.

[0179] In some embodiments, the control information may further include scheduling information for receiving multicast broadcast services (MBS).

[0180] In some embodiments, the channel status information (CSI) configuration parameter may indicate one or more reference signal radio resources.

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

[0182] In some embodiments, the UE may transmit channel status information (CSI) reports based on periodic CSI resources. CSI configuration parameters may indicate periodic CSI reports.

[0183] In one embodiment, a user terminal (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 a first CSI configuration parameter. The UE may measure one or more second reference signals based on a 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 signals. The UE may transmit a second CSI report associated with one or more unicast services based on the measurement of the second reference signals.

[0184] In some embodiments, a first channel status information (CSI) configuration parameter may indicate a first radio resource of one or more first reference signals, and a 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 exemplary blocks and modules described herein with respect to various exemplary embodiments may be implemented or run using general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, 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, microprocessors, any conventional processor, controllers, microcontrollers, or state machines. In some examples, the 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 working with a DSP core, or any other such configuration).

[0187] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. Instructions or code may be stored or transmitted on a computer-readable medium for the implementation of the function. Other examples for implementations of the functions disclosed herein are also within the scope of this disclosure. Implementations of the function may be via physically colocate or distributed elements (e.g., at various locations), including the distribution of parts of the function so as to be implemented at different physical locations.

[0188] Computer-readable media include, but are not limited to, non-temporary computer storage media. Non-temporary storage media may be accessed by general-purpose or dedicated computers. Examples of non-temporary 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. Non-temporary media may be used to carry or store desired program code means (e.g., instructions and / or data structures) and may be accessed by general-purpose or dedicated computers or general-purpose or dedicated processors. In some examples, software / program code may be transmitted from a remote source (e.g., a website, 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. The combinations in the examples above are also within the realm of computer-readable media.

[0189] As used in this disclosure, the use of the term "or" in the list of items is comprehensive. This indicates a list of items. A list of items may be preceded by a phrase such as “at least one of the following” or “one or more of the following.” 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, when used in this disclosure, the phrase “based on” preceding a list of conditions should not be interpreted as “based solely on” the set of conditions, but rather as “based at least partially on” the set of conditions. For example, a result described as “based on condition A” may 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,” and “contain” may be used interchangeably, have the same meaning, and should be interpreted comprehensively and open-ended. The terms “comprise,” “include,” and “contain” may be used before a list of elements and indicate that at least all of the enumerated elements in the list are present, but other elements not in the list may also be present. For example, if A includes B and C, then both {B,C} and {B,C,D} are within the scope of A.

[0191] This disclosure describes exemplary configurations, in relation to the accompanying drawings, which may not represent all possible implementations or all configurations within the scope of this disclosure. The term “exemplary” should not be interpreted as “preferred” or “advantageous compared to other examples,” but rather as “exemplary, example, or illustration.” By reading this disclosure, including the description of embodiments and 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 by combining the embodiments described herein, or certain features of the embodiments, further other embodiments for carrying out the technology described herein may be obtained. Accordingly, this disclosure should be given the broadest scope that is consistent with the principles and novel features disclosed herein, and is not limited to the examples and designs described herein.

[0192] Note 1. A method for hybrid automatic retransmission request (HARQ) feedback transmission, The user terminal (UE) receives a multicast broadcast service (MBS) transport block via the downlink data channel, The aforementioned UE determines that the received power level of the reference signal is greater than a predetermined threshold, A method comprising transmitting HARQ feedback associated with the received MBS transport block by the UE.

[0193] Note 2. The HARQ feedback described above corresponds to the method described in Note 1, which corresponds to a negative response.

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

[0195] Note 4. The state of the user terminal (UE) is the method described in Note 1, which corresponds to the wireless resource control (RRC) connection state.

[0196] Note 5. The method according to Note 1, wherein the state of the user terminal (UE) corresponds to at least one of the following: the Radio Resource Control (RRC) inactive state and the RRC idle state.

[0197] Note 6. Receiving configuration parameters indicating the wireless resources of the aforementioned reference signal, The method according to Appendix 1, further comprising measuring the reference signal using the aforementioned configuration parameters.

[0198] Note 7. The method according to 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] Note 8. The broadcast message is a System Information Block (SIB) message, as described in Note 7.

[0200] Appendix 9. The method according to Appendix 1, further comprising receiving configuration parameters including the predetermined threshold.

[0201] Note 10. The method according to 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] Note 11. The method described in Note 10, wherein the broadcast message is a System Information Block (SIB) message.

[0203] Appendix 12. A method for hybrid automatic retransmission request (HARQ) feedback transmission, The user terminal (UE) receives a multicast broadcast service (MBS) transport block, and the UE receives a block corresponding to a defined state. Deciding to transmit HARQ feedback for the received MBS transport block, A method comprising transmitting the HARQ feedback using a random access process based on the fact that the UE is in the defined state.

[0204] Note 13. Transitioning to the RRC connection state using the aforementioned random access process, The method according to Appendix 12, further comprising transmitting the HARQ feedback for the MBS transport block after transitioning to the RRC connection state.

[0205] Note 14. The method according to Note 13, wherein the transmission of the HARQ feedback includes transmitting the HARQ feedback via an uplink control channel.

[0206] Note 15. Transmitting the HARQ feedback using a random access process includes transmitting a random access preamble, the random access preamble corresponding to the HARQ feedback, as described in Note 12.

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

[0208] Appendix 17. The method according to Appendix 12, further comprising receiving configuration parameters by the UE.

[0209] Appendix 18. The method according to Appendix 17, wherein receiving the configuration by the UE includes receiving configuration parameters indicating that one or more first random access preambles are for a negative response.

[0210] Note 19. The method according to Note 17, wherein receiving configuration parameters by the UE includes receiving configuration parameters indicating that one or more second random access preambles are for affirmative responses.

[0211] Appendix 20. The method according to Appendix 17, wherein receiving configuration parameters by the UE includes receiving a broadcast message containing the configuration parameters.

[0212] Note 21. The method described in Note 20, wherein the broadcast message is a System Information Block (SIB) message.

[0213] Note 22. The method described in Note 12, wherein the random access process is a two-step random access process.

[0214] Note 23. The transmission of the instruction for the Hybrid Automatic Retransmission Request (HARQ) feedback is the method described in Note 22, based on message A of the two-step random access process.

[0215] Note 24. The random access process is a four-step random access process as described in Note 12.

[0216] Note 25. The transmission of the instruction for the Hybrid Automatic Retransmission Request (HARQ) feedback is the method described in Note 24, based on message 3 of the four-step random access process.

[0217] Note 26. The method according to Note 12, wherein the defined state includes at least one of the following: a Radio Resource Control (RRC) inactive state or the RRC idle state.

[0218] Note 27. The Hybrid Automatic Resend Request (HARQ) feedback is the method described in Note 12, including a negative response.

[0219] Note 28. The method according to Note 12, wherein the decision to transmit the HARQ feedback for the received multicast transport service (MBS) transport block is based on the fact that the HARQ feedback is a negative response.

[0220] Appendix 29. A method for hybrid automatic retransmission request (HARQ) feedback transmission, A user terminal (UE) in a defined Radio Resource Control (RRC) state receives a Multicast Broadcast Service (MBS) transport block, It is decided to transmit HARQ feedback for the received MBS transport block, A method comprising transmitting instructions for the HARQ feedback using an uplink control channel based on the UE being in the defined state, wherein the uplink control channel is a common uplink control channel for use by a plurality of UEs in the defined state.

[0221] Appendix 30. The method according to Appendix 29, further comprising receiving one or more broadcast messages containing the configuration parameters of the uplink control channel by the user terminal (UE).

[0222] Note 31. The method according to Note 30, wherein the one or more broadcast messages include a System Information Block (SIB) message.

[0223] Note 32. The configuration parameters are as described in Note 28, wherein the configuration parameters indicate the wireless resources of the uplink control channel.

[0224] Note 33. HARQ feedback is as described in Note 29, including negative responses.

[0225] Appendix 34. The method according to Appendix 29, wherein deciding to transmit HARQ feedback for the received MBS transport block includes deciding to transmit the HARQ feedback if the HARQ feedback includes a negative response.

[0226] Note 35. The method described in Note 29, wherein the transmission of the HARQ feedback instructions is performed while the UE remains in the defined state.

[0227] Appendix 36. A method for reporting channel status information (CSI) feedback, Receiving a logical control channel associated with a multicast broadcast service (MBS) service via a downlink data channel, The logic control channel carries control information including CSI configuration parameters for CSI measurement and CSI reporting. The aforementioned CSI report is associated with the aforementioned MBS service, and is received. Based on the CSI configuration parameters, one or more reference signals are measured, A method comprising transmitting a CSI report based on the measurement of the reference signal and the CSI configuration parameters.

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

[0229] Appendix 38. The method according to Appendix 37, further comprising receiving scheduling information for receiving the logical multicast control channel (MCCH).

[0230] Appendix 39. The method according to Appendix 36, wherein the control information further includes scheduling information for receiving multicast broadcast services (MBS).

[0231] Note 40. Channel status information (CSI) configuration parameters are those that indicate the radio resources of one or more reference signals, as described in Note 36.

[0232] Appendix 41. The method according to Appendix 36, further comprising the user terminal (UE) receiving downlink control information indicating a request for transmission of the channel status information (CSI) report.

[0233] Note 42. The method according to Note 36, wherein transmitting the channel status 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] Appendix 43. A method for reporting channel status information (CSI) feedback, The user terminal (UE) receives CSI configuration parameters, and the CSI configuration parameters are: The first Multicast Broadcast Service (MBS) service CSI configuration parameters, Receiving, including the 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, Based on the measurement of the first reference signal, a first CSI report associated with one or more MBS services is transmitted; A method comprising transmitting a second CSI report associated with one or more unicast services based on the measurement of the second reference signal.

[0235] Note 44. The first channel status information (CSI) configuration parameter indicates the first radio resource of the one or more first reference signals. The method described in Appendix 43, wherein the second CSI configuration parameter indicates a second radio resource of the one or more second reference signals.

[0236] Note 45. The user terminal (UE) receives first downlink control information indicating a first request for transmission of the first channel status information (CSI) report, The method according to Appendix 43, further comprising receiving second downlink control information indicating a second request for transmission of the second CSI report.

[0237] Note 46. Device for use in wireless communication, Antennas for use in the transmission of electromagnetic signals, Memory for maintaining computer-readable code, The device includes a processor for executing the computer-readable code, and the computer-readable code is provided to the device. Receiving a multicast broadcast service (MBS) transport block, wherein the UE receives a defined state corresponding to the receiving state. Deciding to transmit HARQ feedback for the received MBS transport block, A device that, based on the fact that the UE is in the defined state, transmits the HARQ feedback using a random access process.

[0238] Note 47. The above-mentioned device is Using the aforementioned random access process, transition to the RRC connection state, The apparatus according to Appendix 46, further configured to transmit the HARQ feedback for the MBS transport block after transitioning to the RRC connection state.

[0239] Note 48. The apparatus is the apparatus described in Note 47, which transmits the HARQ feedback via the uplink control channel.

[0240] Note 49. The apparatus described in Note 46 transmits a random access preamble, the random access preamble corresponds to the HARQ feedback.

[0241] Appendix 50. The apparatus described in Appendix 49, which remains in the defined state after transmitting the random access preamble.

[0242] Note 51. The device is the device described in Note 46 that receives configuration parameters.

[0243] Note 52. The apparatus as described in Note 51, wherein the configuration parameters indicate that one or more first random access preambles are for negative responses.

[0244] Appendix 53. The apparatus as described in Appendix 51, wherein the configuration parameters indicate that one or more second random access preambles are for affirmative responses.

[0245] Appendix 54. The device is the device described in Appendix 51, which receives a broadcast message containing the configuration parameters.

[0246] Note 55. The broadcast message is a System Information Block (SIB) message, as described in Note 54 for the device.

[0247] Note 56. The apparatus described in Note 46, wherein the random access process is a two-step random access process.

[0248] Note 57. The transmission of the instruction for the Hybrid Automatic Retransmission Request (HARQ) feedback is performed by the apparatus described in Note 56, based on message A of the two-step random access process.

[0249] Note 58. The apparatus described in Note 46, wherein the random access process is a four-step random access process.

[0250] Note 59. The transmission of the instruction for the Hybrid Automatic Retransmission Request (HARQ) feedback is performed by the apparatus described in Note 46, based on message 3 of the four-step random access process.

[0251] Appendix 60. The apparatus as described in Appendix 46, wherein the defined state includes at least one of the following: a Radio Resource Control (RRC) inactive state or the RRC idle state.

[0252] Note 61. The HARQ feedback is the apparatus described in Note 46, including a negative response.

[0253] Note 62. The apparatus described in Note 46 transmits the HARQ feedback for the received multicast transport service (MBS) transport block based on the fact that the HARQ feedback is a negative response.

[0254] Note 63. Device for use in wireless communication, Antennas for use in the transmission of electromagnetic signals, Memory for maintaining computer-readable code, The device includes a processor for executing the computer-readable code, wherein the computer-readable code is provided to the device. Receiving a logical control channel associated with a multicast broadcast service (MBS) service via a downlink data channel, wherein the logical control channel carries control information including CSI configuration parameters for CSI measurement and CSI reporting, and the CSI report is associated with the MBS service, and is received. Based on the CSI configuration parameters, one or more reference signals are measured, A device that transmits a CSI report based on the measurement of the reference signal and the CSI configuration parameters.

[0255] Appendix 64. The logical control channel is a logical multicast control channel (MCCH). The apparatus according to Appendix 63.

[0256] Appendix 65. The apparatus according to Appendix 63, which receives scheduling information for receiving the logical multicast control channel (MCCH).

[0257] Appendix 66. The apparatus according to Appendix 63, wherein the control information further includes scheduling information for receiving a multicast broadcast service (MBS).

[0258] Appendix 67. The channel state information (CSI) configuration parameter indicates a radio resource of the one or more reference signals in the apparatus according to Appendix 63.

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

[0260] Appendix 69. The apparatus according to Appendix 63, which transmits the CSI report based on a periodic CSI resource, and the CSI configuration parameter includes the periodic CSI resource.

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

[0262] Appendix 71. The method according to Appendix 43, further comprising generating, by the UE, the first CSI report and the second CSI report.

[0263] A base station for a mobile communication system, the base station includes a memory for storing instructions, A processor configured to execute instructions for transmitting channel state information (CSI) configuration parameters to a user terminal (UE), 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 one or more second reference signals based on the second CSI configuration parameters, wherein the UE is a base station.

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

[0265] Appendix 74. The base station as described in Appendix 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] Appendix 75. A method for receiving Hybrid Automatic Resend Request (HARQ) feedback, The base station transmits multicast broadcast service (MBS) transport blocks over the downlink data channel, A method comprising receiving HARQ feedback associated with the transmitted MBS transport block by the base station.

[0267] Note 76. Method for receiving Hybrid Automatic Resend Request (HARQ) feedback. , The base station transmits multicast broadcast service (MBS) transport blocks that can be received by user terminals (UEs) corresponding to defined states, A method comprising 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] Appendix 77. A method for receiving Hybrid Automatic Resend Request (HARQ) feedback, The base station transmits multicast broadcast service (MBS) transport blocks that can be received by user terminals (UEs) in a defined radio resource control (RRC) state, A method comprising receiving instructions for the HARQ feedback using an uplink control channel, wherein the instructions are transmitted based on the UE being in the defined state, and the uplink control channel is a common uplink control channel for use by multiple UEs.

[0269] Appendix 78. A method for receiving channel status information (CSI) feedback, The base station transmits a logical control channel associated with a multicast broadcast service (MBS) via a downlink data channel, wherein the logical control channel carries control information including CSI configuration parameters for CSI measurement and CSI reporting, and the CSI report is transmitted in association with the MBS. Transmitting one or more reference signals, A method comprising receiving a CSI report based on a measurement of at least one of the one or more reference signals and the CSI configuration parameters.

[0270] Appendix 79. A method for receiving channel status information (CSI) feedback, The base station transmits CSI configuration parameters, and the CSI configuration parameters are: The first CSI configuration parameter associated with the multicast broadcast service (MBS), The transmission includes a second CSI configuration parameter associated with the unicast service, Transmitting one or more first reference signals based on the first CSI configuration parameters, Transmitting one or more second reference signals based on the second CSI configuration parameters, Receiving a first CSI report associated with one or more MBS based on a measurement of at least one of the one or more first reference signals, A method comprising receiving a second CSI report associated with one or more unicast services based on a 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 12 October 2020. U.S. Provisional Application No. 63 / 090,409 is incorporated herein by reference.

Claims

1. A method for hybrid automatic retransmission request (HARQ) feedback transmission, The user terminal (UE) receives multicast broadcast service (MBS) data from the base station via the downlink data channel, Prior to receiving the MBS data, the UE receives first information from the base station for determining whether or not to transmit HARQ feedback to the MBS data. The UE determines, based on the first information, whether or not to transmit the HARQ feedback to the MBS data, The UE transmits the HARQ feedback to the MBS data in accordance with the determination. Methods that include...

2. The HARQ feedback corresponds to a negative response. The method according to claim 1.

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

4. The method according to claim 1, wherein the state of the user terminal (UE) corresponds to the wireless resource control connection state.

5. The method according to claim 1, wherein the state of the user terminal (UE) corresponds to at least one of the wireless resource control inactive state and the RRC idle state.

6. Receiving second information indicating whether the HARQ feedback transmits only negative responses or both positive and negative responses, Based on the second piece of information, it is determined whether to transmit only negative responses or both positive and negative responses. The method according to claim 1, further comprising:

7. The method according to claim 6, wherein the reception of the second information includes receiving the second information via one of a broadcast message and a message dedicated to radio resource control.

8. A user terminal (UE), Receiving means for receiving multicast broadcast service (MBS) data from a base station via a downlink data channel, comprising: receiving means for receiving first information from the base station prior to receiving the MBS data for determining whether or not to transmit hybrid automatic retransmission request (HARQ) feedback for the MBS data; A determination means for determining whether or not to transmit the HARQ feedback to the MBS data based on the first information, A transmission means for transmitting the HARQ feedback to the MBS data based on the determination, UE, including.

9. A method for receiving Hybrid Automatic Resend Request (HARQ) feedback, The base station transmits multicast broadcast service (MBS) data to the user terminal (UE) via the downlink data channel, Prior to the transmission of the MBS data, the base station has the UE respond to the MBS data. The first information for determining whether or not to transmit HARQ feedback is transmitted to the UE, The base station receives the HARQ feedback for the MBS data from the UE based on the first information, A method that includes this.

10. It is a base station, A transmission means for transmitting multicast broadcast service (MBS) data to a user terminal (UE) via a downlink data channel, comprising: a transmission means for transmitting to the UE, prior to the transmission of the MBS data, first information for determining whether the UE transmits a hybrid automatic retransmission request (HARQ) feedback for the MBS data; Based on the first information, a receiving means for receiving the HARQ feedback from the UE to the MBS data, Base stations including this one.

Images